310 files changed, 17034 insertions, 6802 deletions
diff --git a/BUILD b/BUILD
index 1615486f..8b1046b9 100644
--- a/BUILD
+++ b/BUILD
@@ -266,6 +266,7 @@ cc_library(
         "src/google/protobuf/compiler/java/java_enum_field_lite.cc",
         "src/google/protobuf/compiler/java/java_enum_lite.cc",
         "src/google/protobuf/compiler/java/java_extension.cc",
+        "src/google/protobuf/compiler/java/java_extension_lite.cc",
         "src/google/protobuf/compiler/java/java_field.cc",
         "src/google/protobuf/compiler/java/java_file.cc",
         "src/google/protobuf/compiler/java/java_generator.cc",
@@ -376,6 +377,8 @@ RELATIVE_TEST_PROTOS = [
     "google/protobuf/unittest_preserve_unknown_enum.proto",
     "google/protobuf/unittest_preserve_unknown_enum2.proto",
     "google/protobuf/unittest_proto3_arena.proto",
+    "google/protobuf/unittest_proto3_arena_lite.proto",
+    "google/protobuf/unittest_proto3_lite.proto",
     "google/protobuf/unittest_well_known_types.proto",
     "google/protobuf/util/internal/testdata/anys.proto",
     "google/protobuf/util/internal/testdata/books.proto",
@@ -436,6 +439,7 @@ cc_test(
         "src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc",
         "src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc",
         "src/google/protobuf/compiler/cpp/cpp_unittest.cc",
+        "src/google/protobuf/compiler/cpp/metadata_test.cc",
         "src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc",
         "src/google/protobuf/compiler/importer_unittest.cc",
         "src/google/protobuf/compiler/java/java_doc_comment_unittest.cc",
@@ -460,7 +464,9 @@ cc_test(
         "src/google/protobuf/message_unittest.cc",
         "src/google/protobuf/no_field_presence_test.cc",
         "src/google/protobuf/preserve_unknown_enum_test.cc",
+        "src/google/protobuf/proto3_arena_lite_unittest.cc",
         "src/google/protobuf/proto3_arena_unittest.cc",
+        "src/google/protobuf/proto3_lite_unittest.cc",
         "src/google/protobuf/reflection_ops_unittest.cc",
         "src/google/protobuf/repeated_field_reflection_unittest.cc",
         "src/google/protobuf/repeated_field_unittest.cc",
@@ -535,9 +541,9 @@ java_library(
         "java/util/src/main/java/com/google/protobuf/util/*.java",
     ]),
     deps = [
-      "protobuf_java",
-      "//external:gson",
-      "//external:guava",
+        "protobuf_java",
+        "//external:gson",
+        "//external:guava",
     ],
     visibility = ["//visibility:public"],
 )
@@ -558,6 +564,7 @@ py_library(
             "python/google/protobuf/internal/test_util.py",
         ],
     ),
+    srcs_version = "PY2AND3",
     imports = ["python"],
 )
 
@@ -642,6 +649,7 @@ py_proto_library(
     include = "src",
     default_runtime = "",
     protoc = ":protoc",
+    srcs_version = "PY2AND3",
     deps = [":protobuf_python"],
 )
 
@@ -654,6 +662,7 @@ py_proto_library(
     include = "python",
     default_runtime = ":protobuf_python",
     protoc = ":protoc",
+    srcs_version = "PY2AND3",
     deps = [":python_common_test_protos"],
 )
 
diff --git a/Makefile.am b/Makefile.am
index cadc7d8d..3e988816 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -9,7 +9,7 @@ AUTOMAKE_OPTIONS = foreign
 SUBDIRS = . src
 
 # Always include gmock in distributions.
-DIST_SUBDIRS = $(subdirs) src conformance
+DIST_SUBDIRS = $(subdirs) src conformance benchmarks
 
 # Build gmock before we build protobuf tests.  We don't add gmock to SUBDIRS
 # because then "make check" would also build and run all of gmock's own tests,
@@ -36,6 +36,10 @@ clean-local:
 	  echo "Making clean in conformance"; \
 	  cd conformance && $(MAKE) $(AM_MAKEFLAGS) clean; \
 	fi; \
+	if test -e benchmarks/Makefile; then \
+	  echo "Making clean in benchmarks"; \
+	  cd benchmarks && $(MAKE) $(AM_MAKEFLAGS) clean; \
+	fi; \
 	if test -e objectivec/DevTools; then \
 	  echo "Cleaning any ObjC pyc files"; \
 	  rm -f objectivec/DevTools/*.pyc; \
@@ -154,6 +158,7 @@ csharp_EXTRA_DIST=                                                           \
   csharp/src/Google.Protobuf/Reflection/MethodDescriptor.cs                  \
   csharp/src/Google.Protobuf/Reflection/OneofAccessor.cs                     \
   csharp/src/Google.Protobuf/Reflection/OneofDescriptor.cs                   \
+  csharp/src/Google.Protobuf/Reflection/OriginalNameAttribute.cs             \
   csharp/src/Google.Protobuf/Reflection/PackageDescriptor.cs                 \
   csharp/src/Google.Protobuf/Reflection/PartialClasses.cs                    \
   csharp/src/Google.Protobuf/Reflection/ReflectionUtil.cs                    \
diff --git a/benchmarks/Makefile.am b/benchmarks/Makefile.am
new file mode 100644
index 00000000..1e162eb1
--- /dev/null
+++ b/benchmarks/Makefile.am
@@ -0,0 +1,66 @@
+
+benchmarks_protoc_inputs =                                     \
+  benchmarks.proto                                             \
+  benchmark_messages_proto3.proto
+
+benchmarks_protoc_inputs_proto2 =                              \
+  benchmark_messages_proto2.proto
+
+benchmarks_protoc_outputs =                                    \
+  benchmarks.pb.cc                                             \
+  benchmarks.pb.h                                              \
+  benchmark_messages_proto3.pb.cc                              \
+  benchmark_messages_proto3.pb.h
+
+benchmarks_protoc_outputs_proto2 =                             \
+  benchmark_messages_proto2.pb.cc                              \
+  benchmark_messages_proto2.pb.h
+
+bin_PROGRAMS = generate-datasets
+
+generate_datasets_LDADD = $(top_srcdir)/src/libprotobuf.la
+generate_datasets_SOURCES = generate_datasets.cc
+generate_datasets_CPPFLAGS = -I$(top_srcdir)/src -I$(srcdir)
+nodist_generate_datasets_SOURCES =                             \
+  $(benchmarks_protoc_outputs)                                 \
+  $(benchmarks_protoc_outputs_proto2)
+
+# Explicit deps because BUILT_SOURCES are only done before a "make all/check"
+# so a direct "make test_cpp" could fail if parallel enough.
+# See: https://www.gnu.org/software/automake/manual/html_node/Built-Sources-Example.html#Recording-Dependencies-manually
+generate_datasets-generate_datasets.$(OBJEXT): benchmarks.pb.h
+
+$(benchmarks_protoc_outputs): protoc_middleman
+$(benchmarks_protoc_outputs_proto2): protoc_middleman2
+
+CLEANFILES =                                                   \
+  $(benchmarks_protoc_outputs)                                 \
+  $(benchmarks_protoc_outputs_proto2)                          \
+  protoc_middleman                                             \
+  protoc_middleman2                                            \
+  dataset.*
+
+if USE_EXTERNAL_PROTOC
+
+protoc_middleman: $(benchmarks_protoc_inputs)
+	$(PROTOC) -I$(srcdir) -I$(top_srcdir) --cpp_out=. $(benchmarks_protoc_inputs)
+	touch protoc_middleman
+
+protoc_middleman2: $(benchmarks_protoc_inputs_proto2)
+	$(PROTOC) -I$(srcdir) -I$(top_srcdir) --cpp_out=. $(benchmarks_protoc_inputs_proto2)
+	touch protoc_middleman2
+
+else
+
+# We have to cd to $(srcdir) before executing protoc because $(protoc_inputs) is
+# relative to srcdir, which may not be the same as the current directory when
+# building out-of-tree.
+protoc_middleman: $(top_srcdir)/src/protoc$(EXEEXT) $(benchmarks_protoc_inputs) $(well_known_type_protoc_inputs)
+	oldpwd=`pwd` && ( cd $(srcdir) && $$oldpwd/../src/protoc$(EXEEXT) -I. -I$(top_srcdir)/src --cpp_out=$$oldpwd $(benchmarks_protoc_inputs) )
+	touch protoc_middleman
+
+protoc_middleman2: $(top_srcdir)/src/protoc$(EXEEXT) $(benchmarks_protoc_inputs_proto2) $(well_known_type_protoc_inputs)
+	oldpwd=`pwd` && ( cd $(srcdir) && $$oldpwd/../src/protoc$(EXEEXT) -I. -I$(top_srcdir)/src --cpp_out=$$oldpwd $(benchmarks_protoc_inputs_proto2) )
+	touch protoc_middleman
+
+endif
diff --git a/benchmarks/README.md b/benchmarks/README.md
new file mode 100644
index 00000000..c9027805
--- /dev/null
+++ b/benchmarks/README.md
@@ -0,0 +1,28 @@
+
+# Protocol Buffers Benchmarks
+
+This directory contains benchmarking schemas and data sets that you
+can use to test a variety of performance scenarios against your
+protobuf language runtime.
+
+The schema for the datasets is described in `benchmarks.proto`.
+
+Generate the data sets like so:
+
+```
+$ make
+$ ./generate-datasets
+Wrote dataset: dataset.google_message1_proto3.pb
+Wrote dataset: dataset.google_message1_proto2.pb
+Wrote dataset: dataset.google_message2.pb
+$
+```
+
+Each data set will be written to its own file.  Benchmarks will
+likely want to run several benchmarks against each data set (parse,
+serialize, possibly JSON, possibly using different APIs, etc).
+
+We would like to add more data sets.  In general we will favor data sets
+that make the overall suite diverse without being too large or having
+too many similar tests.  Ideally everyone can run through the entire
+suite without the test run getting too long.
diff --git a/benchmarks/google_speed.proto b/benchmarks/benchmark_messages_proto2.proto
index 16f6d678..01f67a1a 100644
--- a/benchmarks/google_speed.proto
+++ b/benchmarks/benchmark_messages_proto2.proto
@@ -1,11 +1,14 @@
+// Benchmark messages for proto2.
+
 syntax = "proto2";
 
-package benchmarks;
+package benchmarks.proto2;
+option java_package = "com.google.protobuf.benchmarks";
 
-option java_outer_classname = "GoogleSpeed";
+// This is the default, but we specify it here explicitly.
 option optimize_for = SPEED;
 
-message SpeedMessage1 {
+message GoogleMessage1 {
   required string field1 = 1;
   optional string field9 = 9;
   optional string field18 = 18;
@@ -40,7 +43,7 @@ message SpeedMessage1 {
   optional int32 field23 = 23 [default=0];
   optional bool field24 = 24 [default=false];
   optional int32 field25 = 25 [default=0];
-  optional SpeedMessage1SubMessage field15 = 15;
+  optional GoogleMessage1SubMessage field15 = 15;
   optional bool field78 = 78;
   optional int32 field67 = 67 [default=0];
   optional int32 field68 = 68;
@@ -49,7 +52,7 @@ message SpeedMessage1 {
   optional int32 field131 = 131 [default=0];
 }
 
-message SpeedMessage1SubMessage {
+message GoogleMessage1SubMessage {
   optional int32 field1 = 1 [default=0];
   optional int32 field2 = 2 [default=0];
   optional int32 field3 = 3 [default=0];
@@ -72,7 +75,7 @@ message SpeedMessage1SubMessage {
   optional uint64 field300 = 300;
 }
 
-message SpeedMessage2 {
+message GoogleMessage2 {
   optional string field1 = 1;
   optional int64 field3 = 3;
   optional int64 field4 = 4;
@@ -112,7 +115,7 @@ message SpeedMessage2 {
     repeated int32 field73 = 73;
     optional int32 field20 = 20 [default=0];
     optional string field24 = 24;
-    optional SpeedMessage2GroupedMessage field31 = 31;
+    optional GoogleMessage2GroupedMessage field31 = 31;
   }
   repeated string field128 = 128;
   optional int64 field131 = 131;
@@ -123,7 +126,7 @@ message SpeedMessage2 {
   optional bool field206 = 206 [default=false];
 }
 
-message SpeedMessage2GroupedMessage {
+message GoogleMessage2GroupedMessage {
   optional float field1 = 1;
   optional float field2 = 2;
   optional float field3 = 3 [default=0.0];
diff --git a/benchmarks/benchmark_messages_proto3.proto b/benchmarks/benchmark_messages_proto3.proto
new file mode 100644
index 00000000..32f58698
--- /dev/null
+++ b/benchmarks/benchmark_messages_proto3.proto
@@ -0,0 +1,76 @@
+// Benchmark messages for proto3.
+
+syntax = "proto3";
+
+package benchmarks.proto3;
+option java_package = "com.google.protobuf.benchmarks";
+
+// This is the default, but we specify it here explicitly.
+option optimize_for = SPEED;
+
+message GoogleMessage1 {
+  string field1 = 1;
+  string field9 = 9;
+  string field18 = 18;
+  bool field80 = 80;
+  bool field81 = 81;
+  int32 field2 = 2;
+  int32 field3 = 3;
+  int32 field280 = 280;
+  int32 field6 = 6;
+  int64 field22 = 22;
+  string field4 = 4;
+  repeated fixed64 field5 = 5;
+  bool field59 = 59;
+  string field7 = 7;
+  int32 field16 = 16;
+  int32 field130 = 130;
+  bool field12 = 12;
+  bool field17 = 17;
+  bool field13 = 13;
+  bool field14 = 14;
+  int32 field104 = 104;
+  int32 field100 = 100;
+  int32 field101 = 101;
+  string field102 = 102;
+  string field103 = 103;
+  int32 field29 = 29;
+  bool field30 = 30;
+  int32 field60 = 60;
+  int32 field271 = 271;
+  int32 field272 = 272;
+  int32 field150 = 150;
+  int32 field23 = 23;
+  bool field24 = 24;
+  int32 field25 = 25;
+  GoogleMessage1SubMessage field15 = 15;
+  bool field78 = 78;
+  int32 field67 = 67;
+  int32 field68 = 68;
+  int32 field128 = 128;
+  string field129 = 129;
+  int32 field131 = 131;
+}
+
+message GoogleMessage1SubMessage {
+  int32 field1 = 1;
+  int32 field2 = 2;
+  int32 field3 = 3;
+  string field15 = 15;
+  bool field12 = 12;
+  int64 field13 = 13;
+  int64 field14 = 14;
+  int32 field16 = 16;
+  int32 field19 = 19;
+  bool field20  = 20;
+  bool field28 = 28;
+  fixed64 field21 = 21;
+  int32 field22 = 22;
+  bool field23 = 23;
+  bool field206 = 206;
+  fixed32 field203 = 203;
+  int32 field204 = 204;
+  string field205 = 205;
+  uint64 field207 = 207;
+  uint64 field300 = 300;
+}
diff --git a/benchmarks/benchmarks.proto b/benchmarks/benchmarks.proto
new file mode 100644
index 00000000..51c0b548
--- /dev/null
+++ b/benchmarks/benchmarks.proto
@@ -0,0 +1,63 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+package benchmarks;
+option java_package = "com.google.protobuf.benchmarks";
+
+message BenchmarkDataset {
+  // Name of the benchmark dataset.  This should be unique across all datasets.
+  // Should only contain word characters: [a-zA-Z0-9_]
+  string name = 1;
+
+  // Fully-qualified name of the protobuf message for this dataset.
+  // It will be one of the messages defined benchmark_messages_proto2.proto
+  // or benchmark_messages_proto3.proto.
+  //
+  // Implementations that do not support reflection can implement this with
+  // an explicit "if/else" chain that lists every known message defined
+  // in those files.
+  string message_name = 2;
+
+  // The payload(s) for this dataset.  They should be parsed or serialized
+  // in sequence, in a loop, ie.
+  //
+  //  while (!benchmarkDone) {  // Benchmark runner decides when to exit.
+  //    for (i = 0; i < benchmark.payload.length; i++) {
+  //      parse(benchmark.payload[i])
+  //    }
+  //  }
+  //
+  // This is intended to let datasets include a variety of data to provide
+  // potentially more realistic results than just parsing the same message
+  // over and over.  A single message parsed repeatedly could yield unusually
+  // good branch prediction performance.
+  repeated bytes payload = 3;
+}
diff --git a/benchmarks/generate_datasets.cc b/benchmarks/generate_datasets.cc
new file mode 100644
index 00000000..61e7adf1
--- /dev/null
+++ b/benchmarks/generate_datasets.cc
@@ -0,0 +1,117 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <fstream>
+#include <iostream>
+#include "benchmarks.pb.h"
+
+using benchmarks::BenchmarkDataset;
+using google::protobuf::Descriptor;
+using google::protobuf::DescriptorPool;
+using google::protobuf::Message;
+using google::protobuf::MessageFactory;
+
+std::set<std::string> names;
+
+const char *file_prefix = "dataset.";
+const char *file_suffix = ".pb";
+
+void WriteFileWithPayloads(const std::string& name,
+                           const std::string& message_name,
+                           const std::vector<std::string>& payload) {
+  if (!names.insert(name).second) {
+    std::cerr << "Duplicate test name: " << name << "\n";
+    abort();
+  }
+
+  // First verify that this message name exists in our set of benchmark messages
+  // and that these payloads are valid for the given message.
+  const Descriptor* d =
+      DescriptorPool::generated_pool()->FindMessageTypeByName(message_name);
+
+  if (!d) {
+    std::cerr << "For dataset " << name << ", no such message: "
+              << message_name << "\n";
+    abort();
+  }
+
+  Message* m = MessageFactory::generated_factory()->GetPrototype(d)->New();
+
+  for (size_t i = 0; i < payload.size(); i++) {
+    if (!m->ParseFromString(payload[i])) {
+      std::cerr << "For dataset " << name << ", payload[" << i << "] fails "
+                << "to parse\n";
+      abort();
+    }
+  }
+
+  BenchmarkDataset dataset;
+  dataset.set_name(name);
+  dataset.set_message_name(message_name);
+  for (size_t i = 0; i < payload.size(); i++) {
+    dataset.add_payload()->assign(payload[i]);
+  }
+
+  std::ofstream writer;
+  std::string fname = file_prefix + name + file_suffix;
+  writer.open(fname.c_str());
+  dataset.SerializeToOstream(&writer);
+  writer.close();
+
+  std::cerr << "Wrote dataset: " << fname << "\n";
+}
+
+void WriteFile(const std::string& name, const std::string& message_name,
+               const std::string& payload) {
+  std::vector<std::string> payloads;
+  payloads.push_back(payload);
+  WriteFileWithPayloads(name, message_name, payloads);
+}
+
+std::string ReadFile(const std::string& name) {
+  std::ifstream file(name.c_str());
+  GOOGLE_CHECK(file.is_open()) << "Couldn't find file '" << name <<
+                                  "', please make sure you are running "
+                                  "this command from the benchmarks/ "
+                                  "directory.\n";
+  return std::string((std::istreambuf_iterator<char>(file)),
+                     std::istreambuf_iterator<char>());
+}
+
+int main() {
+  WriteFile("google_message1_proto3", "benchmarks.proto3.GoogleMessage1",
+            ReadFile("google_message1.dat"));
+  WriteFile("google_message1_proto2", "benchmarks.proto2.GoogleMessage1",
+            ReadFile("google_message1.dat"));
+
+  // Not in proto3 because it has a group, which is not supported.
+  WriteFile("google_message2", "benchmarks.proto2.GoogleMessage2",
+            ReadFile("google_message2.dat"));
+}
diff --git a/cmake/extract_includes.bat.in b/cmake/extract_includes.bat.in
index c76973c9..b593e0c9 100644
--- a/cmake/extract_includes.bat.in
+++ b/cmake/extract_includes.bat.in
@@ -23,7 +23,6 @@ copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\command_line_
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\cpp\cpp_generator.h include\google\protobuf\compiler\cpp\cpp_generator.h
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\csharp\csharp_generator.h include\google\protobuf\compiler\csharp\csharp_generator.h
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\csharp\csharp_names.h include\google\protobuf\compiler\csharp\csharp_names.h
-copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\csharp\csharp_options.h include\google\protobuf\compiler\csharp\csharp_options.h
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\importer.h include\google\protobuf\compiler\importer.h
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\java\java_generator.h include\google\protobuf\compiler\java\java_generator.h
 copy ${PROTOBUF_SOURCE_WIN32_PATH}\..\src\google\protobuf\compiler\java\java_names.h include\google\protobuf\compiler\java\java_names.h
diff --git a/cmake/tests.cmake b/cmake/tests.cmake
index 941f33d8..76fdf8ef 100644
--- a/cmake/tests.cmake
+++ b/cmake/tests.cmake
@@ -52,6 +52,8 @@ set(tests_protos
   google/protobuf/unittest_preserve_unknown_enum.proto
   google/protobuf/unittest_preserve_unknown_enum2.proto
   google/protobuf/unittest_proto3_arena.proto
+  google/protobuf/unittest_proto3_arena_lite.proto
+  google/protobuf/unittest_proto3_lite.proto
   google/protobuf/unittest_well_known_types.proto
   google/protobuf/util/internal/testdata/anys.proto
   google/protobuf/util/internal/testdata/books.proto
@@ -116,6 +118,7 @@ set(tests_files
   ${protobuf_source_dir}/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/cpp/cpp_unittest.cc
+  ${protobuf_source_dir}/src/google/protobuf/compiler/cpp/metadata_test.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/importer_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/compiler/java/java_doc_comment_unittest.cc
@@ -140,7 +143,9 @@ set(tests_files
   ${protobuf_source_dir}/src/google/protobuf/message_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/no_field_presence_test.cc
   ${protobuf_source_dir}/src/google/protobuf/preserve_unknown_enum_test.cc
+  ${protobuf_source_dir}/src/google/protobuf/proto3_arena_lite_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/proto3_arena_unittest.cc
+  ${protobuf_source_dir}/src/google/protobuf/proto3_lite_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/reflection_ops_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/repeated_field_reflection_unittest.cc
   ${protobuf_source_dir}/src/google/protobuf/repeated_field_unittest.cc
diff --git a/configure.ac b/configure.ac
index 33a6c64d..d56a7047 100644
--- a/configure.ac
+++ b/configure.ac
@@ -180,5 +180,5 @@ export CFLAGS
 export CXXFLAGS
 AC_CONFIG_SUBDIRS([gmock])
 
-AC_CONFIG_FILES([Makefile src/Makefile conformance/Makefile protobuf.pc protobuf-lite.pc])
+AC_CONFIG_FILES([Makefile src/Makefile benchmarks/Makefile conformance/Makefile protobuf.pc protobuf-lite.pc])
 AC_OUTPUT
diff --git a/conformance/failure_list_ruby.txt b/conformance/failure_list_ruby.txt
index ade0ff4c..7c12da06 100644
--- a/conformance/failure_list_ruby.txt
+++ b/conformance/failure_list_ruby.txt
@@ -80,7 +80,6 @@ JsonInput.Int32FieldMaxFloatValue.JsonOutput
 JsonInput.Int32FieldMaxFloatValue.ProtobufOutput
 JsonInput.Int32FieldMinFloatValue.JsonOutput
 JsonInput.Int32FieldMinFloatValue.ProtobufOutput
-JsonInput.Int32FieldMinValue.JsonOutput
 JsonInput.Int32FieldStringValue.JsonOutput
 JsonInput.Int32FieldStringValue.ProtobufOutput
 JsonInput.Int32FieldStringValueEscaped.JsonOutput
@@ -125,7 +124,6 @@ JsonInput.OptionalUint64Wrapper.ProtobufOutput
 JsonInput.OptionalWrapperTypesWithNonDefaultValue.JsonOutput
 JsonInput.OptionalWrapperTypesWithNonDefaultValue.ProtobufOutput
 JsonInput.OriginalProtoFieldName.JsonOutput
-JsonInput.OriginalProtoFieldName.ProtobufOutput
 JsonInput.PrimitiveRepeatedField.JsonOutput
 JsonInput.PrimitiveRepeatedField.ProtobufOutput
 JsonInput.RepeatedBoolWrapper.JsonOutput
diff --git a/csharp/src/AddressBook/AddPerson.cs b/csharp/src/AddressBook/AddPerson.cs
index 6eeb9f6e..62d1788d 100644
--- a/csharp/src/AddressBook/AddPerson.cs
+++ b/csharp/src/AddressBook/AddPerson.cs
@@ -73,13 +73,13 @@ namespace Google.Protobuf.Examples.AddressBook
                 switch (type)
                 {
                     case "mobile":
-                        phoneNumber.Type = Person.Types.PhoneType.MOBILE;
+                        phoneNumber.Type = Person.Types.PhoneType.Mobile;
                         break;
                     case "home":
-                        phoneNumber.Type = Person.Types.PhoneType.HOME;
+                        phoneNumber.Type = Person.Types.PhoneType.Home;
                         break;
                     case "work":
-                        phoneNumber.Type = Person.Types.PhoneType.WORK;
+                        phoneNumber.Type = Person.Types.PhoneType.Work;
                         break;
                     default:
                         output.Write("Unknown phone type. Using default.");
diff --git a/csharp/src/AddressBook/Addressbook.cs b/csharp/src/AddressBook/Addressbook.cs
index 166dd49a..362e1cb6 100644
--- a/csharp/src/AddressBook/Addressbook.cs
+++ b/csharp/src/AddressBook/Addressbook.cs
@@ -228,9 +228,9 @@ namespace Google.Protobuf.Examples.AddressBook {
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     public static partial class Types {
       public enum PhoneType {
-        MOBILE = 0,
-        HOME = 1,
-        WORK = 2,
+        [pbr::OriginalName("MOBILE")] Mobile = 0,
+        [pbr::OriginalName("HOME")] Home = 1,
+        [pbr::OriginalName("WORK")] Work = 2,
       }
 
       [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -273,7 +273,7 @@ namespace Google.Protobuf.Examples.AddressBook {
 
         /// <summary>Field number for the "type" field.</summary>
         public const int TypeFieldNumber = 2;
-        private global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType type_ = global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType.MOBILE;
+        private global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType type_ = 0;
         public global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType Type {
           get { return type_; }
           set {
@@ -300,7 +300,7 @@ namespace Google.Protobuf.Examples.AddressBook {
         public override int GetHashCode() {
           int hash = 1;
           if (Number.Length != 0) hash ^= Number.GetHashCode();
-          if (Type != global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType.MOBILE) hash ^= Type.GetHashCode();
+          if (Type != 0) hash ^= Type.GetHashCode();
           return hash;
         }
 
@@ -313,7 +313,7 @@ namespace Google.Protobuf.Examples.AddressBook {
             output.WriteRawTag(10);
             output.WriteString(Number);
           }
-          if (Type != global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType.MOBILE) {
+          if (Type != 0) {
             output.WriteRawTag(16);
             output.WriteEnum((int) Type);
           }
@@ -324,7 +324,7 @@ namespace Google.Protobuf.Examples.AddressBook {
           if (Number.Length != 0) {
             size += 1 + pb::CodedOutputStream.ComputeStringSize(Number);
           }
-          if (Type != global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType.MOBILE) {
+          if (Type != 0) {
             size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Type);
           }
           return size;
@@ -337,7 +337,7 @@ namespace Google.Protobuf.Examples.AddressBook {
           if (other.Number.Length != 0) {
             Number = other.Number;
           }
-          if (other.Type != global::Google.Protobuf.Examples.AddressBook.Person.Types.PhoneType.MOBILE) {
+          if (other.Type != 0) {
             Type = other.Type;
           }
         }
diff --git a/csharp/src/AddressBook/ListPeople.cs b/csharp/src/AddressBook/ListPeople.cs
index 3979430f..3758c1bc 100644
--- a/csharp/src/AddressBook/ListPeople.cs
+++ b/csharp/src/AddressBook/ListPeople.cs
@@ -55,13 +55,13 @@ namespace Google.Protobuf.Examples.AddressBook
                 {
                     switch (phoneNumber.Type)
                     {
-                        case Person.Types.PhoneType.MOBILE:
+                        case Person.Types.PhoneType.Mobile:
                             Console.Write("  Mobile phone #: ");
                             break;
-                        case Person.Types.PhoneType.HOME:
+                        case Person.Types.PhoneType.Home:
                             Console.Write("  Home phone #: ");
                             break;
-                        case Person.Types.PhoneType.WORK:
+                        case Person.Types.PhoneType.Work:
                             Console.Write("  Work phone #: ");
                             break;
                     }
diff --git a/csharp/src/Google.Protobuf.Conformance/Conformance.cs b/csharp/src/Google.Protobuf.Conformance/Conformance.cs
index 7d85d28c..1674a673 100644
--- a/csharp/src/Google.Protobuf.Conformance/Conformance.cs
+++ b/csharp/src/Google.Protobuf.Conformance/Conformance.cs
@@ -199,15 +199,15 @@ namespace Conformance {
   }
   #region Enums
   public enum WireFormat {
-    UNSPECIFIED = 0,
-    PROTOBUF = 1,
-    JSON = 2,
+    [pbr::OriginalName("UNSPECIFIED")] Unspecified = 0,
+    [pbr::OriginalName("PROTOBUF")] Protobuf = 1,
+    [pbr::OriginalName("JSON")] Json = 2,
   }
 
   public enum ForeignEnum {
-    FOREIGN_FOO = 0,
-    FOREIGN_BAR = 1,
-    FOREIGN_BAZ = 2,
+    [pbr::OriginalName("FOREIGN_FOO")] ForeignFoo = 0,
+    [pbr::OriginalName("FOREIGN_BAR")] ForeignBar = 1,
+    [pbr::OriginalName("FOREIGN_BAZ")] ForeignBaz = 2,
   }
 
   #endregion
@@ -278,7 +278,7 @@ namespace Conformance {
 
     /// <summary>Field number for the "requested_output_format" field.</summary>
     public const int RequestedOutputFormatFieldNumber = 3;
-    private global::Conformance.WireFormat requestedOutputFormat_ = global::Conformance.WireFormat.UNSPECIFIED;
+    private global::Conformance.WireFormat requestedOutputFormat_ = 0;
     /// <summary>
     ///  Which format should the testee serialize its message to?
     /// </summary>
@@ -328,7 +328,7 @@ namespace Conformance {
       int hash = 1;
       if (payloadCase_ == PayloadOneofCase.ProtobufPayload) hash ^= ProtobufPayload.GetHashCode();
       if (payloadCase_ == PayloadOneofCase.JsonPayload) hash ^= JsonPayload.GetHashCode();
-      if (RequestedOutputFormat != global::Conformance.WireFormat.UNSPECIFIED) hash ^= RequestedOutputFormat.GetHashCode();
+      if (RequestedOutputFormat != 0) hash ^= RequestedOutputFormat.GetHashCode();
       hash ^= (int) payloadCase_;
       return hash;
     }
@@ -346,7 +346,7 @@ namespace Conformance {
         output.WriteRawTag(18);
         output.WriteString(JsonPayload);
       }
-      if (RequestedOutputFormat != global::Conformance.WireFormat.UNSPECIFIED) {
+      if (RequestedOutputFormat != 0) {
         output.WriteRawTag(24);
         output.WriteEnum((int) RequestedOutputFormat);
       }
@@ -360,7 +360,7 @@ namespace Conformance {
       if (payloadCase_ == PayloadOneofCase.JsonPayload) {
         size += 1 + pb::CodedOutputStream.ComputeStringSize(JsonPayload);
       }
-      if (RequestedOutputFormat != global::Conformance.WireFormat.UNSPECIFIED) {
+      if (RequestedOutputFormat != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) RequestedOutputFormat);
       }
       return size;
@@ -370,7 +370,7 @@ namespace Conformance {
       if (other == null) {
         return;
       }
-      if (other.RequestedOutputFormat != global::Conformance.WireFormat.UNSPECIFIED) {
+      if (other.RequestedOutputFormat != 0) {
         RequestedOutputFormat = other.RequestedOutputFormat;
       }
       switch (other.PayloadCase) {
@@ -1044,7 +1044,7 @@ namespace Conformance {
 
     /// <summary>Field number for the "optional_nested_enum" field.</summary>
     public const int OptionalNestedEnumFieldNumber = 21;
-    private global::Conformance.TestAllTypes.Types.NestedEnum optionalNestedEnum_ = global::Conformance.TestAllTypes.Types.NestedEnum.FOO;
+    private global::Conformance.TestAllTypes.Types.NestedEnum optionalNestedEnum_ = 0;
     public global::Conformance.TestAllTypes.Types.NestedEnum OptionalNestedEnum {
       get { return optionalNestedEnum_; }
       set {
@@ -1054,7 +1054,7 @@ namespace Conformance {
 
     /// <summary>Field number for the "optional_foreign_enum" field.</summary>
     public const int OptionalForeignEnumFieldNumber = 22;
-    private global::Conformance.ForeignEnum optionalForeignEnum_ = global::Conformance.ForeignEnum.FOREIGN_FOO;
+    private global::Conformance.ForeignEnum optionalForeignEnum_ = 0;
     public global::Conformance.ForeignEnum OptionalForeignEnum {
       get { return optionalForeignEnum_; }
       set {
@@ -2079,8 +2079,8 @@ namespace Conformance {
       if (OptionalBytes.Length != 0) hash ^= OptionalBytes.GetHashCode();
       if (optionalNestedMessage_ != null) hash ^= OptionalNestedMessage.GetHashCode();
       if (optionalForeignMessage_ != null) hash ^= OptionalForeignMessage.GetHashCode();
-      if (OptionalNestedEnum != global::Conformance.TestAllTypes.Types.NestedEnum.FOO) hash ^= OptionalNestedEnum.GetHashCode();
-      if (OptionalForeignEnum != global::Conformance.ForeignEnum.FOREIGN_FOO) hash ^= OptionalForeignEnum.GetHashCode();
+      if (OptionalNestedEnum != 0) hash ^= OptionalNestedEnum.GetHashCode();
+      if (OptionalForeignEnum != 0) hash ^= OptionalForeignEnum.GetHashCode();
       if (OptionalStringPiece.Length != 0) hash ^= OptionalStringPiece.GetHashCode();
       if (OptionalCord.Length != 0) hash ^= OptionalCord.GetHashCode();
       if (recursiveMessage_ != null) hash ^= RecursiveMessage.GetHashCode();
@@ -2247,11 +2247,11 @@ namespace Conformance {
         output.WriteRawTag(154, 1);
         output.WriteMessage(OptionalForeignMessage);
       }
-      if (OptionalNestedEnum != global::Conformance.TestAllTypes.Types.NestedEnum.FOO) {
+      if (OptionalNestedEnum != 0) {
         output.WriteRawTag(168, 1);
         output.WriteEnum((int) OptionalNestedEnum);
       }
-      if (OptionalForeignEnum != global::Conformance.ForeignEnum.FOREIGN_FOO) {
+      if (OptionalForeignEnum != 0) {
         output.WriteRawTag(176, 1);
         output.WriteEnum((int) OptionalForeignEnum);
       }
@@ -2492,10 +2492,10 @@ namespace Conformance {
       if (optionalForeignMessage_ != null) {
         size += 2 + pb::CodedOutputStream.ComputeMessageSize(OptionalForeignMessage);
       }
-      if (OptionalNestedEnum != global::Conformance.TestAllTypes.Types.NestedEnum.FOO) {
+      if (OptionalNestedEnum != 0) {
         size += 2 + pb::CodedOutputStream.ComputeEnumSize((int) OptionalNestedEnum);
       }
-      if (OptionalForeignEnum != global::Conformance.ForeignEnum.FOREIGN_FOO) {
+      if (OptionalForeignEnum != 0) {
         size += 2 + pb::CodedOutputStream.ComputeEnumSize((int) OptionalForeignEnum);
       }
       if (OptionalStringPiece.Length != 0) {
@@ -2719,10 +2719,10 @@ namespace Conformance {
         }
         OptionalForeignMessage.MergeFrom(other.OptionalForeignMessage);
       }
-      if (other.OptionalNestedEnum != global::Conformance.TestAllTypes.Types.NestedEnum.FOO) {
+      if (other.OptionalNestedEnum != 0) {
         OptionalNestedEnum = other.OptionalNestedEnum;
       }
-      if (other.OptionalForeignEnum != global::Conformance.ForeignEnum.FOREIGN_FOO) {
+      if (other.OptionalForeignEnum != 0) {
         OptionalForeignEnum = other.OptionalForeignEnum;
       }
       if (other.OptionalStringPiece.Length != 0) {
@@ -3448,13 +3448,13 @@ namespace Conformance {
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     public static partial class Types {
       public enum NestedEnum {
-        FOO = 0,
-        BAR = 1,
-        BAZ = 2,
+        [pbr::OriginalName("FOO")] Foo = 0,
+        [pbr::OriginalName("BAR")] Bar = 1,
+        [pbr::OriginalName("BAZ")] Baz = 2,
         /// <summary>
         ///  Intentionally negative.
         /// </summary>
-        NEG = -1,
+        [pbr::OriginalName("NEG")] Neg = -1,
       }
 
       [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
diff --git a/csharp/src/Google.Protobuf.Conformance/Program.cs b/csharp/src/Google.Protobuf.Conformance/Program.cs
index f3f7e295..19827c48 100644
--- a/csharp/src/Google.Protobuf.Conformance/Program.cs
+++ b/csharp/src/Google.Protobuf.Conformance/Program.cs
@@ -109,10 +109,10 @@ namespace Google.Protobuf.Conformance
             {
                 switch (request.RequestedOutputFormat)
                 {
-                    case global::Conformance.WireFormat.JSON:
+                    case global::Conformance.WireFormat.Json:
                         var formatter = new JsonFormatter(new JsonFormatter.Settings(false, typeRegistry));
                         return new ConformanceResponse { JsonPayload = formatter.Format(message) };
-                    case global::Conformance.WireFormat.PROTOBUF:
+                    case global::Conformance.WireFormat.Protobuf:
                         return new ConformanceResponse { ProtobufPayload = message.ToByteString() };
                     default:
                         throw new Exception("Unsupported request output format: " + request.PayloadCase);
diff --git a/csharp/src/Google.Protobuf.Test/FieldCodecTest.cs b/csharp/src/Google.Protobuf.Test/FieldCodecTest.cs
index 38ba227f..c616470e 100644
--- a/csharp/src/Google.Protobuf.Test/FieldCodecTest.cs
+++ b/csharp/src/Google.Protobuf.Test/FieldCodecTest.cs
@@ -58,7 +58,7 @@ namespace Google.Protobuf
             new FieldCodecTestData<float>(FieldCodec.ForFloat(100), 1234.5f, "Float"),
             new FieldCodecTestData<double>(FieldCodec.ForDouble(100), 1234567890.5d, "Double"),
             new FieldCodecTestData<ForeignEnum>(
-                FieldCodec.ForEnum(100, t => (int) t, t => (ForeignEnum) t), ForeignEnum.FOREIGN_BAZ, "Enum"),
+                FieldCodec.ForEnum(100, t => (int) t, t => (ForeignEnum) t), ForeignEnum.ForeignBaz, "Enum"),
             new FieldCodecTestData<ForeignMessage>(
                 FieldCodec.ForMessage(100, ForeignMessage.Parser), new ForeignMessage { C = 10 }, "Message"),
         };
diff --git a/csharp/src/Google.Protobuf.Test/GeneratedMessageTest.cs b/csharp/src/Google.Protobuf.Test/GeneratedMessageTest.cs
index 5c2a052b..8b153d69 100644
--- a/csharp/src/Google.Protobuf.Test/GeneratedMessageTest.cs
+++ b/csharp/src/Google.Protobuf.Test/GeneratedMessageTest.cs
@@ -66,13 +66,13 @@ namespace Google.Protobuf
             Assert.AreEqual(0, message.SingleFixed32);
             Assert.AreEqual(0L, message.SingleFixed64);
             Assert.AreEqual(0.0f, message.SingleFloat);
-            Assert.AreEqual(ForeignEnum.FOREIGN_UNSPECIFIED, message.SingleForeignEnum);
+            Assert.AreEqual(ForeignEnum.ForeignUnspecified, message.SingleForeignEnum);
             Assert.IsNull(message.SingleForeignMessage);
-            Assert.AreEqual(ImportEnum.IMPORT_ENUM_UNSPECIFIED, message.SingleImportEnum);
+            Assert.AreEqual(ImportEnum.Unspecified, message.SingleImportEnum);
             Assert.IsNull(message.SingleImportMessage);
             Assert.AreEqual(0, message.SingleInt32);
             Assert.AreEqual(0L, message.SingleInt64);
-            Assert.AreEqual(TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED, message.SingleNestedEnum);
+            Assert.AreEqual(TestAllTypes.Types.NestedEnum.Unspecified, message.SingleNestedEnum);
             Assert.IsNull(message.SingleNestedMessage);
             Assert.IsNull(message.SinglePublicImportMessage);
             Assert.AreEqual(0, message.SingleSfixed32);
@@ -145,13 +145,13 @@ namespace Google.Protobuf
                 SingleFixed32 = 23,
                 SingleFixed64 = 1234567890123,
                 SingleFloat = 12.25f,
-                SingleForeignEnum = ForeignEnum.FOREIGN_BAR,
+                SingleForeignEnum = ForeignEnum.ForeignBar,
                 SingleForeignMessage = new ForeignMessage { C = 10 },
-                SingleImportEnum = ImportEnum.IMPORT_BAZ,
+                SingleImportEnum = ImportEnum.ImportBaz,
                 SingleImportMessage = new ImportMessage { D = 20 },
                 SingleInt32 = 100,
                 SingleInt64 = 3210987654321,
-                SingleNestedEnum = TestAllTypes.Types.NestedEnum.FOO,
+                SingleNestedEnum = TestAllTypes.Types.NestedEnum.Foo,
                 SingleNestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 35 },
                 SinglePublicImportMessage = new PublicImportMessage { E = 54 },
                 SingleSfixed32 = -123,
@@ -179,13 +179,13 @@ namespace Google.Protobuf
                 RepeatedFixed32 = { uint.MaxValue, 23 },
                 RepeatedFixed64 = { ulong.MaxValue, 1234567890123 },
                 RepeatedFloat = { 100f, 12.25f },
-                RepeatedForeignEnum = { ForeignEnum.FOREIGN_FOO, ForeignEnum.FOREIGN_BAR },
+                RepeatedForeignEnum = { ForeignEnum.ForeignFoo, ForeignEnum.ForeignBar },
                 RepeatedForeignMessage = { new ForeignMessage(), new ForeignMessage { C = 10 } },
-                RepeatedImportEnum = { ImportEnum.IMPORT_BAZ, ImportEnum.IMPORT_ENUM_UNSPECIFIED },
+                RepeatedImportEnum = { ImportEnum.ImportBaz, ImportEnum.Unspecified },
                 RepeatedImportMessage = { new ImportMessage { D = 20 }, new ImportMessage { D = 25 } },
                 RepeatedInt32 = { 100, 200 },
                 RepeatedInt64 = { 3210987654321, long.MaxValue },
-                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.FOO, TestAllTypes.Types.NestedEnum.NEG },
+                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.Foo, TestAllTypes.Types.NestedEnum.Neg },
                 RepeatedNestedMessage = { new TestAllTypes.Types.NestedMessage { Bb = 35 }, new TestAllTypes.Types.NestedMessage { Bb = 10 } },
                 RepeatedPublicImportMessage = { new PublicImportMessage { E = 54 }, new PublicImportMessage { E = -1 } },
                 RepeatedSfixed32 = { -123, 123 },
@@ -224,8 +224,8 @@ namespace Google.Protobuf
                     { 5, new ForeignMessage() },
                 },
                 MapInt32Enum = {
-                    { 1, MapEnum.MAP_ENUM_BAR },
-                    { 2000, MapEnum.MAP_ENUM_FOO }
+                    { 1, MapEnum.Bar },
+                    { 2000, MapEnum.Foo }
                 }
             };
 
@@ -249,7 +249,7 @@ namespace Google.Protobuf
             Assert.AreEqual(1, parsed.MapInt32Bytes.Count);
             Assert.AreEqual(ByteString.Empty, parsed.MapInt32Bytes[0]);
         }
-        
+
         [Test]
         public void MapWithOnlyValue()
         {
@@ -449,7 +449,7 @@ namespace Google.Protobuf
                 SingleFloat = 12.25f,
                 SingleInt32 = 100,
                 SingleInt64 = 3210987654321,
-                SingleNestedEnum = TestAllTypes.Types.NestedEnum.FOO,
+                SingleNestedEnum = TestAllTypes.Types.NestedEnum.Foo,
                 SingleSfixed32 = -123,
                 SingleSfixed64 = -12345678901234,
                 SingleSint32 = -456,
@@ -479,7 +479,7 @@ namespace Google.Protobuf
                 RepeatedFloat = { 100f, 12.25f },
                 RepeatedInt32 = { 100, 200 },
                 RepeatedInt64 = { 3210987654321, long.MaxValue },
-                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.FOO, TestAllTypes.Types.NestedEnum.NEG },
+                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.Foo, TestAllTypes.Types.NestedEnum.Neg },
                 RepeatedSfixed32 = { -123, 123 },
                 RepeatedSfixed64 = { -12345678901234, 12345678901234 },
                 RepeatedSint32 = { -456, 100 },
@@ -670,7 +670,7 @@ namespace Google.Protobuf
         {
             // 130, 3 is the message tag
             // 1 is the data length - but there's no data.
-            var data = new byte[] { 130, 3, 1 };            
+            var data = new byte[] { 130, 3, 1 };
             Assert.Throws<InvalidProtocolBufferException>(() => TestAllTypes.Parser.ParseFrom(data));
         }
 
@@ -720,4 +720,4 @@ namespace Google.Protobuf
             Assert.AreEqual("{ \"c\": 31 }", writer.ToString());
         }
     }
-}
+}
+\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf.Test/JsonFormatterTest.cs b/csharp/src/Google.Protobuf.Test/JsonFormatterTest.cs
index 344d727b..0b6cd7e6 100644
--- a/csharp/src/Google.Protobuf.Test/JsonFormatterTest.cs
+++ b/csharp/src/Google.Protobuf.Test/JsonFormatterTest.cs
@@ -75,13 +75,13 @@ namespace Google.Protobuf
                 SingleFixed32 = 23,
                 SingleFixed64 = 1234567890123,
                 SingleFloat = 12.25f,
-                SingleForeignEnum = ForeignEnum.FOREIGN_BAR,
+                SingleForeignEnum = ForeignEnum.ForeignBar,
                 SingleForeignMessage = new ForeignMessage { C = 10 },
-                SingleImportEnum = ImportEnum.IMPORT_BAZ,
+                SingleImportEnum = ImportEnum.ImportBaz,
                 SingleImportMessage = new ImportMessage { D = 20 },
                 SingleInt32 = 100,
                 SingleInt64 = 3210987654321,
-                SingleNestedEnum = TestAllTypes.Types.NestedEnum.FOO,
+                SingleNestedEnum = TestAllTypes.Types.NestedEnum.Foo,
                 SingleNestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 35 },
                 SinglePublicImportMessage = new PublicImportMessage { E = 54 },
                 SingleSfixed32 = -123,
@@ -174,14 +174,14 @@ namespace Google.Protobuf
         [Test]
         public void UnknownEnumValueNumeric_RepeatedField()
         {
-            var message = new TestAllTypes { RepeatedForeignEnum = { ForeignEnum.FOREIGN_BAZ, (ForeignEnum) 100, ForeignEnum.FOREIGN_FOO } };
+            var message = new TestAllTypes { RepeatedForeignEnum = { ForeignEnum.ForeignBaz, (ForeignEnum) 100, ForeignEnum.ForeignFoo } };
             AssertJson("{ 'repeatedForeignEnum': [ 'FOREIGN_BAZ', 100, 'FOREIGN_FOO' ] }", JsonFormatter.Default.Format(message));
         }
 
         [Test]
         public void UnknownEnumValueNumeric_MapField()
         {
-            var message = new TestMap { MapInt32Enum = { { 1, MapEnum.MAP_ENUM_FOO }, { 2, (MapEnum) 100 }, { 3, MapEnum.MAP_ENUM_BAR } } };
+            var message = new TestMap { MapInt32Enum = { { 1, MapEnum.Foo }, { 2, (MapEnum) 100 }, { 3, MapEnum.Bar } } };
             AssertJson("{ 'mapInt32Enum': { '1': 'MAP_ENUM_FOO', '2': 100, '3': 'MAP_ENUM_BAR' } }", JsonFormatter.Default.Format(message));
         }
 
diff --git a/csharp/src/Google.Protobuf.Test/JsonParserTest.cs b/csharp/src/Google.Protobuf.Test/JsonParserTest.cs
index d21da58a..684f52b4 100644
--- a/csharp/src/Google.Protobuf.Test/JsonParserTest.cs
+++ b/csharp/src/Google.Protobuf.Test/JsonParserTest.cs
@@ -142,8 +142,8 @@ namespace Google.Protobuf
         [TestCase(typeof(DoubleValue), "1.5", 1.5d)]
         public void Wrappers_Standalone(System.Type wrapperType, string json, object expectedValue)
         {
-            IMessage parsed = (IMessage) Activator.CreateInstance(wrapperType);
-            IMessage expected = (IMessage) Activator.CreateInstance(wrapperType);
+            IMessage parsed = (IMessage)Activator.CreateInstance(wrapperType);
+            IMessage expected = (IMessage)Activator.CreateInstance(wrapperType);
             JsonParser.Default.Merge(parsed, "null");
             Assert.AreEqual(expected, parsed);
 
@@ -640,7 +640,7 @@ namespace Google.Protobuf
             var parsed = Timestamp.Parser.ParseJson(json);
             Assert.AreEqual(WrapInQuotes(expectedFormatted), parsed.ToString());
         }
-        
+
         [Test]
         [TestCase("2015-10-09 14:46:23.123456789Z", Description = "No T between date and time")]
         [TestCase("2015/10/09T14:46:23.123456789Z", Description = "Wrong date separators")]
@@ -886,9 +886,9 @@ namespace Google.Protobuf
         }
 
         [Test]
-        [TestCase("\"FOREIGN_BAR\"", ForeignEnum.FOREIGN_BAR)]
-        [TestCase("5", ForeignEnum.FOREIGN_BAR)]
-        [TestCase("100", (ForeignEnum) 100)]
+        [TestCase("\"FOREIGN_BAR\"", ForeignEnum.ForeignBar)]
+        [TestCase("5", ForeignEnum.ForeignBar)]
+        [TestCase("100", (ForeignEnum)100)]
         public void EnumValid(string value, ForeignEnum expectedValue)
         {
             string json = "{ \"singleForeignEnum\": " + value + " }";
@@ -922,4 +922,4 @@ namespace Google.Protobuf
             return '"' + text + '"';
         }
     }
-}
+}
+\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf.Test/Reflection/DescriptorsTest.cs b/csharp/src/Google.Protobuf.Test/Reflection/DescriptorsTest.cs
index 086a4e98..52d5a676 100644
--- a/csharp/src/Google.Protobuf.Test/Reflection/DescriptorsTest.cs
+++ b/csharp/src/Google.Protobuf.Test/Reflection/DescriptorsTest.cs
@@ -195,7 +195,7 @@ namespace Google.Protobuf.Reflection
             Assert.AreEqual(value, enumType.Values[1]);
             Assert.AreEqual("FOREIGN_FOO", value.Name);
             Assert.AreEqual(4, value.Number);
-            Assert.AreEqual((int) ForeignEnum.FOREIGN_FOO, value.Number);
+            Assert.AreEqual((int) ForeignEnum.ForeignFoo, value.Number);
             Assert.AreEqual(value, enumType.FindValueByNumber(4));
             Assert.Null(enumType.FindValueByName("NO_SUCH_VALUE"));
             for (int i = 0; i < enumType.Values.Count; i++)
diff --git a/csharp/src/Google.Protobuf.Test/Reflection/FieldAccessTest.cs b/csharp/src/Google.Protobuf.Test/Reflection/FieldAccessTest.cs
index 936e41c6..a488af30 100644
--- a/csharp/src/Google.Protobuf.Test/Reflection/FieldAccessTest.cs
+++ b/csharp/src/Google.Protobuf.Test/Reflection/FieldAccessTest.cs
@@ -128,7 +128,7 @@ namespace Google.Protobuf.Reflection
             fields[TestAllTypes.SingleInt32FieldNumber].Accessor.SetValue(message, 500);
             fields[TestAllTypes.SingleStringFieldNumber].Accessor.SetValue(message, "It's a string");
             fields[TestAllTypes.SingleBytesFieldNumber].Accessor.SetValue(message, ByteString.CopyFrom(99, 98, 97));
-            fields[TestAllTypes.SingleForeignEnumFieldNumber].Accessor.SetValue(message, ForeignEnum.FOREIGN_FOO);
+            fields[TestAllTypes.SingleForeignEnumFieldNumber].Accessor.SetValue(message, ForeignEnum.ForeignFoo);
             fields[TestAllTypes.SingleForeignMessageFieldNumber].Accessor.SetValue(message, new ForeignMessage { C = 12345 });
             fields[TestAllTypes.SingleDoubleFieldNumber].Accessor.SetValue(message, 20150701.5);
 
@@ -138,7 +138,7 @@ namespace Google.Protobuf.Reflection
                 SingleInt32 = 500,
                 SingleString = "It's a string",
                 SingleBytes = ByteString.CopyFrom(99, 98, 97),
-                SingleForeignEnum = ForeignEnum.FOREIGN_FOO,
+                SingleForeignEnum = ForeignEnum.ForeignFoo,
                 SingleForeignMessage = new ForeignMessage { C = 12345 },
                 SingleDouble = 20150701.5
             };
diff --git a/csharp/src/Google.Protobuf.Test/SampleMessages.cs b/csharp/src/Google.Protobuf.Test/SampleMessages.cs
index 8a9c7f86..ffa4e2a7 100644
--- a/csharp/src/Google.Protobuf.Test/SampleMessages.cs
+++ b/csharp/src/Google.Protobuf.Test/SampleMessages.cs
@@ -54,13 +54,13 @@ namespace Google.Protobuf
                 SingleFixed32 = 23,
                 SingleFixed64 = 1234567890123,
                 SingleFloat = 12.25f,
-                SingleForeignEnum = ForeignEnum.FOREIGN_BAR,
+                SingleForeignEnum = ForeignEnum.ForeignBar,
                 SingleForeignMessage = new ForeignMessage { C = 10 },
-                SingleImportEnum = ImportEnum.IMPORT_BAZ,
+                SingleImportEnum = ImportEnum.ImportBaz,
                 SingleImportMessage = new ImportMessage { D = 20 },
                 SingleInt32 = 100,
                 SingleInt64 = 3210987654321,
-                SingleNestedEnum = TestAllTypes.Types.NestedEnum.FOO,
+                SingleNestedEnum = TestAllTypes.Types.NestedEnum.Foo,
                 SingleNestedMessage = new TestAllTypes.Types.NestedMessage { Bb = 35 },
                 SinglePublicImportMessage = new PublicImportMessage { E = 54 },
                 SingleSfixed32 = -123,
@@ -76,13 +76,13 @@ namespace Google.Protobuf
                 RepeatedFixed32 = { UInt32.MaxValue, 23 },
                 RepeatedFixed64 = { UInt64.MaxValue, 1234567890123 },
                 RepeatedFloat = { 100f, 12.25f },
-                RepeatedForeignEnum = { ForeignEnum.FOREIGN_FOO, ForeignEnum.FOREIGN_BAR },
+                RepeatedForeignEnum = { ForeignEnum.ForeignFoo, ForeignEnum.ForeignBar },
                 RepeatedForeignMessage = { new ForeignMessage(), new ForeignMessage { C = 10 } },
-                RepeatedImportEnum = { ImportEnum.IMPORT_BAZ, ImportEnum.IMPORT_ENUM_UNSPECIFIED },
+                RepeatedImportEnum = { ImportEnum.ImportBaz, ImportEnum.Unspecified },
                 RepeatedImportMessage = { new ImportMessage { D = 20 }, new ImportMessage { D = 25 } },
                 RepeatedInt32 = { 100, 200 },
                 RepeatedInt64 = { 3210987654321, Int64.MaxValue },
-                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.FOO, TestAllTypes.Types.NestedEnum.NEG },
+                RepeatedNestedEnum = { TestAllTypes.Types.NestedEnum.Foo, TestAllTypes.Types.NestedEnum.Neg },
                 RepeatedNestedMessage = { new TestAllTypes.Types.NestedMessage { Bb = 35 }, new TestAllTypes.Types.NestedMessage { Bb = 10 } },
                 RepeatedPublicImportMessage = { new PublicImportMessage { E = 54 }, new PublicImportMessage { E = -1 } },
                 RepeatedSfixed32 = { -123, 123 },
@@ -92,8 +92,8 @@ namespace Google.Protobuf
                 RepeatedString = { "foo", "bar" },
                 RepeatedUint32 = { UInt32.MaxValue, UInt32.MinValue },
                 RepeatedUint64 = { UInt64.MaxValue, UInt32.MinValue },
-                OneofString = "Oneof string"                
+                OneofString = "Oneof string"
             };
         }
     }
-}
+}
+\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf.Test/TestCornerCases.cs b/csharp/src/Google.Protobuf.Test/TestCornerCases.cs
index 03fa1855..248f5fa9 100644
--- a/csharp/src/Google.Protobuf.Test/TestCornerCases.cs
+++ b/csharp/src/Google.Protobuf.Test/TestCornerCases.cs
@@ -43,8 +43,8 @@ namespace Google.Protobuf
             NegativeEnumMessage msg = new NegativeEnumMessage
             {
                 Value = NegativeEnum.MinusOne,
-                Values = { NegativeEnum.NEGATIVE_ENUM_ZERO, NegativeEnum.MinusOne, NegativeEnum.FiveBelow },
-                PackedValues = { NegativeEnum.NEGATIVE_ENUM_ZERO, NegativeEnum.MinusOne, NegativeEnum.FiveBelow }
+                Values = { NegativeEnum.Zero, NegativeEnum.MinusOne, NegativeEnum.FiveBelow },
+                PackedValues = { NegativeEnum.Zero, NegativeEnum.MinusOne, NegativeEnum.FiveBelow }
             };
 
             Assert.AreEqual(58, msg.CalculateSize());
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
index 27c04787..3ba4a2b6 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/MapUnittestProto3.cs
@@ -164,9 +164,9 @@ namespace Google.Protobuf.TestProtos {
   }
   #region Enums
   public enum MapEnum {
-    MAP_ENUM_FOO = 0,
-    MAP_ENUM_BAR = 1,
-    MAP_ENUM_BAZ = 2,
+    [pbr::OriginalName("MAP_ENUM_FOO")] Foo = 0,
+    [pbr::OriginalName("MAP_ENUM_BAR")] Bar = 1,
+    [pbr::OriginalName("MAP_ENUM_BAZ")] Baz = 2,
   }
 
   #endregion
@@ -1358,7 +1358,7 @@ namespace Google.Protobuf.TestProtos {
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     public static partial class Types {
       public enum Type {
-        TYPE_FOO = 0,
+        [pbr::OriginalName("TYPE_FOO")] Foo = 0,
       }
 
     }
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
index 7b824dc7..263e17c0 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestImportProto3.cs
@@ -42,10 +42,10 @@ namespace Google.Protobuf.TestProtos {
   }
   #region Enums
   public enum ImportEnum {
-    IMPORT_ENUM_UNSPECIFIED = 0,
-    IMPORT_FOO = 7,
-    IMPORT_BAR = 8,
-    IMPORT_BAZ = 9,
+    [pbr::OriginalName("IMPORT_ENUM_UNSPECIFIED")] Unspecified = 0,
+    [pbr::OriginalName("IMPORT_FOO")] ImportFoo = 7,
+    [pbr::OriginalName("IMPORT_BAR")] ImportBar = 8,
+    [pbr::OriginalName("IMPORT_BAZ")] ImportBaz = 9,
   }
 
   #endregion
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
index 586f01c8..7d4451b0 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestIssues.cs
@@ -66,14 +66,14 @@ namespace UnitTest.Issues.TestProtos {
   }
   #region Enums
   public enum NegativeEnum {
-    NEGATIVE_ENUM_ZERO = 0,
-    FiveBelow = -5,
-    MinusOne = -1,
+    [pbr::OriginalName("NEGATIVE_ENUM_ZERO")] Zero = 0,
+    [pbr::OriginalName("FiveBelow")] FiveBelow = -5,
+    [pbr::OriginalName("MinusOne")] MinusOne = -1,
   }
 
   public enum DeprecatedEnum {
-    DEPRECATED_ZERO = 0,
-    one = 1,
+    [pbr::OriginalName("DEPRECATED_ZERO")] DeprecatedZero = 0,
+    [pbr::OriginalName("one")] One = 1,
   }
 
   #endregion
@@ -356,7 +356,7 @@ namespace UnitTest.Issues.TestProtos {
 
     /// <summary>Field number for the "value" field.</summary>
     public const int ValueFieldNumber = 1;
-    private global::UnitTest.Issues.TestProtos.NegativeEnum value_ = global::UnitTest.Issues.TestProtos.NegativeEnum.NEGATIVE_ENUM_ZERO;
+    private global::UnitTest.Issues.TestProtos.NegativeEnum value_ = 0;
     public global::UnitTest.Issues.TestProtos.NegativeEnum Value {
       get { return value_; }
       set {
@@ -401,7 +401,7 @@ namespace UnitTest.Issues.TestProtos {
 
     public override int GetHashCode() {
       int hash = 1;
-      if (Value != global::UnitTest.Issues.TestProtos.NegativeEnum.NEGATIVE_ENUM_ZERO) hash ^= Value.GetHashCode();
+      if (Value != 0) hash ^= Value.GetHashCode();
       hash ^= values_.GetHashCode();
       hash ^= packedValues_.GetHashCode();
       return hash;
@@ -412,7 +412,7 @@ namespace UnitTest.Issues.TestProtos {
     }
 
     public void WriteTo(pb::CodedOutputStream output) {
-      if (Value != global::UnitTest.Issues.TestProtos.NegativeEnum.NEGATIVE_ENUM_ZERO) {
+      if (Value != 0) {
         output.WriteRawTag(8);
         output.WriteEnum((int) Value);
       }
@@ -422,7 +422,7 @@ namespace UnitTest.Issues.TestProtos {
 
     public int CalculateSize() {
       int size = 0;
-      if (Value != global::UnitTest.Issues.TestProtos.NegativeEnum.NEGATIVE_ENUM_ZERO) {
+      if (Value != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Value);
       }
       size += values_.CalculateSize(_repeated_values_codec);
@@ -434,7 +434,7 @@ namespace UnitTest.Issues.TestProtos {
       if (other == null) {
         return;
       }
-      if (other.Value != global::UnitTest.Issues.TestProtos.NegativeEnum.NEGATIVE_ENUM_ZERO) {
+      if (other.Value != 0) {
         Value = other.Value;
       }
       values_.Add(other.values_);
@@ -620,7 +620,7 @@ namespace UnitTest.Issues.TestProtos {
 
     /// <summary>Field number for the "EnumValue" field.</summary>
     public const int EnumValueFieldNumber = 5;
-    private global::UnitTest.Issues.TestProtos.DeprecatedEnum enumValue_ = global::UnitTest.Issues.TestProtos.DeprecatedEnum.DEPRECATED_ZERO;
+    private global::UnitTest.Issues.TestProtos.DeprecatedEnum enumValue_ = 0;
     [global::System.ObsoleteAttribute()]
     public global::UnitTest.Issues.TestProtos.DeprecatedEnum EnumValue {
       get { return enumValue_; }
@@ -665,7 +665,7 @@ namespace UnitTest.Issues.TestProtos {
       hash ^= primitiveArray_.GetHashCode();
       if (messageValue_ != null) hash ^= MessageValue.GetHashCode();
       hash ^= messageArray_.GetHashCode();
-      if (EnumValue != global::UnitTest.Issues.TestProtos.DeprecatedEnum.DEPRECATED_ZERO) hash ^= EnumValue.GetHashCode();
+      if (EnumValue != 0) hash ^= EnumValue.GetHashCode();
       hash ^= enumArray_.GetHashCode();
       return hash;
     }
@@ -685,7 +685,7 @@ namespace UnitTest.Issues.TestProtos {
         output.WriteMessage(MessageValue);
       }
       messageArray_.WriteTo(output, _repeated_messageArray_codec);
-      if (EnumValue != global::UnitTest.Issues.TestProtos.DeprecatedEnum.DEPRECATED_ZERO) {
+      if (EnumValue != 0) {
         output.WriteRawTag(40);
         output.WriteEnum((int) EnumValue);
       }
@@ -702,7 +702,7 @@ namespace UnitTest.Issues.TestProtos {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(MessageValue);
       }
       size += messageArray_.CalculateSize(_repeated_messageArray_codec);
-      if (EnumValue != global::UnitTest.Issues.TestProtos.DeprecatedEnum.DEPRECATED_ZERO) {
+      if (EnumValue != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) EnumValue);
       }
       size += enumArray_.CalculateSize(_repeated_enumArray_codec);
@@ -724,7 +724,7 @@ namespace UnitTest.Issues.TestProtos {
         MessageValue.MergeFrom(other.MessageValue);
       }
       messageArray_.Add(other.messageArray_);
-      if (other.EnumValue != global::UnitTest.Issues.TestProtos.DeprecatedEnum.DEPRECATED_ZERO) {
+      if (other.EnumValue != 0) {
         EnumValue = other.EnumValue;
       }
       enumArray_.Add(other.enumArray_);
@@ -1435,7 +1435,7 @@ namespace UnitTest.Issues.TestProtos {
     public const int NameFieldNumber = 1;
     private string name_ = "";
     /// <summary>
-    ///  json_name field options are not properly handled during deserialization
+    ///  Message for testing the effects for of the json_name option
     /// </summary>
     public string Name {
       get { return name_; }
diff --git a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
index d8465448..b8d159bb 100644
--- a/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
+++ b/csharp/src/Google.Protobuf.Test/TestProtos/UnittestProto3.cs
@@ -193,39 +193,39 @@ namespace Google.Protobuf.TestProtos {
   }
   #region Enums
   public enum ForeignEnum {
-    FOREIGN_UNSPECIFIED = 0,
-    FOREIGN_FOO = 4,
-    FOREIGN_BAR = 5,
-    FOREIGN_BAZ = 6,
+    [pbr::OriginalName("FOREIGN_UNSPECIFIED")] ForeignUnspecified = 0,
+    [pbr::OriginalName("FOREIGN_FOO")] ForeignFoo = 4,
+    [pbr::OriginalName("FOREIGN_BAR")] ForeignBar = 5,
+    [pbr::OriginalName("FOREIGN_BAZ")] ForeignBaz = 6,
   }
 
   /// <summary>
   ///  Test an enum that has multiple values with the same number.
   /// </summary>
   public enum TestEnumWithDupValue {
-    TEST_ENUM_WITH_DUP_VALUE_UNSPECIFIED = 0,
-    FOO1 = 1,
-    BAR1 = 2,
-    BAZ = 3,
-    FOO2 = 1,
-    BAR2 = 2,
+    [pbr::OriginalName("TEST_ENUM_WITH_DUP_VALUE_UNSPECIFIED")] Unspecified = 0,
+    [pbr::OriginalName("FOO1")] Foo1 = 1,
+    [pbr::OriginalName("BAR1")] Bar1 = 2,
+    [pbr::OriginalName("BAZ")] Baz = 3,
+    [pbr::OriginalName("FOO2")] Foo2 = 1,
+    [pbr::OriginalName("BAR2")] Bar2 = 2,
   }
 
   /// <summary>
   ///  Test an enum with large, unordered values.
   /// </summary>
   public enum TestSparseEnum {
-    TEST_SPARSE_ENUM_UNSPECIFIED = 0,
-    SPARSE_A = 123,
-    SPARSE_B = 62374,
-    SPARSE_C = 12589234,
-    SPARSE_D = -15,
-    SPARSE_E = -53452,
+    [pbr::OriginalName("TEST_SPARSE_ENUM_UNSPECIFIED")] Unspecified = 0,
+    [pbr::OriginalName("SPARSE_A")] SparseA = 123,
+    [pbr::OriginalName("SPARSE_B")] SparseB = 62374,
+    [pbr::OriginalName("SPARSE_C")] SparseC = 12589234,
+    [pbr::OriginalName("SPARSE_D")] SparseD = -15,
+    [pbr::OriginalName("SPARSE_E")] SparseE = -53452,
     /// <summary>
     ///  In proto3, value 0 must be the first one specified
     ///  SPARSE_F = 0;
     /// </summary>
-    SPARSE_G = 2,
+    [pbr::OriginalName("SPARSE_G")] SparseG = 2,
   }
 
   #endregion
@@ -505,7 +505,7 @@ namespace Google.Protobuf.TestProtos {
 
     /// <summary>Field number for the "single_nested_enum" field.</summary>
     public const int SingleNestedEnumFieldNumber = 21;
-    private global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum singleNestedEnum_ = global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED;
+    private global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum singleNestedEnum_ = 0;
     public global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum SingleNestedEnum {
       get { return singleNestedEnum_; }
       set {
@@ -515,7 +515,7 @@ namespace Google.Protobuf.TestProtos {
 
     /// <summary>Field number for the "single_foreign_enum" field.</summary>
     public const int SingleForeignEnumFieldNumber = 22;
-    private global::Google.Protobuf.TestProtos.ForeignEnum singleForeignEnum_ = global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED;
+    private global::Google.Protobuf.TestProtos.ForeignEnum singleForeignEnum_ = 0;
     public global::Google.Protobuf.TestProtos.ForeignEnum SingleForeignEnum {
       get { return singleForeignEnum_; }
       set {
@@ -525,7 +525,7 @@ namespace Google.Protobuf.TestProtos {
 
     /// <summary>Field number for the "single_import_enum" field.</summary>
     public const int SingleImportEnumFieldNumber = 23;
-    private global::Google.Protobuf.TestProtos.ImportEnum singleImportEnum_ = global::Google.Protobuf.TestProtos.ImportEnum.IMPORT_ENUM_UNSPECIFIED;
+    private global::Google.Protobuf.TestProtos.ImportEnum singleImportEnum_ = 0;
     public global::Google.Protobuf.TestProtos.ImportEnum SingleImportEnum {
       get { return singleImportEnum_; }
       set {
@@ -892,9 +892,9 @@ namespace Google.Protobuf.TestProtos {
       if (singleNestedMessage_ != null) hash ^= SingleNestedMessage.GetHashCode();
       if (singleForeignMessage_ != null) hash ^= SingleForeignMessage.GetHashCode();
       if (singleImportMessage_ != null) hash ^= SingleImportMessage.GetHashCode();
-      if (SingleNestedEnum != global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED) hash ^= SingleNestedEnum.GetHashCode();
-      if (SingleForeignEnum != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) hash ^= SingleForeignEnum.GetHashCode();
-      if (SingleImportEnum != global::Google.Protobuf.TestProtos.ImportEnum.IMPORT_ENUM_UNSPECIFIED) hash ^= SingleImportEnum.GetHashCode();
+      if (SingleNestedEnum != 0) hash ^= SingleNestedEnum.GetHashCode();
+      if (SingleForeignEnum != 0) hash ^= SingleForeignEnum.GetHashCode();
+      if (SingleImportEnum != 0) hash ^= SingleImportEnum.GetHashCode();
       if (singlePublicImportMessage_ != null) hash ^= SinglePublicImportMessage.GetHashCode();
       hash ^= repeatedInt32_.GetHashCode();
       hash ^= repeatedInt64_.GetHashCode();
@@ -1003,15 +1003,15 @@ namespace Google.Protobuf.TestProtos {
         output.WriteRawTag(162, 1);
         output.WriteMessage(SingleImportMessage);
       }
-      if (SingleNestedEnum != global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED) {
+      if (SingleNestedEnum != 0) {
         output.WriteRawTag(168, 1);
         output.WriteEnum((int) SingleNestedEnum);
       }
-      if (SingleForeignEnum != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (SingleForeignEnum != 0) {
         output.WriteRawTag(176, 1);
         output.WriteEnum((int) SingleForeignEnum);
       }
-      if (SingleImportEnum != global::Google.Protobuf.TestProtos.ImportEnum.IMPORT_ENUM_UNSPECIFIED) {
+      if (SingleImportEnum != 0) {
         output.WriteRawTag(184, 1);
         output.WriteEnum((int) SingleImportEnum);
       }
@@ -1115,13 +1115,13 @@ namespace Google.Protobuf.TestProtos {
       if (singleImportMessage_ != null) {
         size += 2 + pb::CodedOutputStream.ComputeMessageSize(SingleImportMessage);
       }
-      if (SingleNestedEnum != global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED) {
+      if (SingleNestedEnum != 0) {
         size += 2 + pb::CodedOutputStream.ComputeEnumSize((int) SingleNestedEnum);
       }
-      if (SingleForeignEnum != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (SingleForeignEnum != 0) {
         size += 2 + pb::CodedOutputStream.ComputeEnumSize((int) SingleForeignEnum);
       }
-      if (SingleImportEnum != global::Google.Protobuf.TestProtos.ImportEnum.IMPORT_ENUM_UNSPECIFIED) {
+      if (SingleImportEnum != 0) {
         size += 2 + pb::CodedOutputStream.ComputeEnumSize((int) SingleImportEnum);
       }
       if (singlePublicImportMessage_ != null) {
@@ -1231,13 +1231,13 @@ namespace Google.Protobuf.TestProtos {
         }
         SingleImportMessage.MergeFrom(other.SingleImportMessage);
       }
-      if (other.SingleNestedEnum != global::Google.Protobuf.TestProtos.TestAllTypes.Types.NestedEnum.NESTED_ENUM_UNSPECIFIED) {
+      if (other.SingleNestedEnum != 0) {
         SingleNestedEnum = other.SingleNestedEnum;
       }
-      if (other.SingleForeignEnum != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (other.SingleForeignEnum != 0) {
         SingleForeignEnum = other.SingleForeignEnum;
       }
-      if (other.SingleImportEnum != global::Google.Protobuf.TestProtos.ImportEnum.IMPORT_ENUM_UNSPECIFIED) {
+      if (other.SingleImportEnum != 0) {
         SingleImportEnum = other.SingleImportEnum;
       }
       if (other.singlePublicImportMessage_ != null) {
@@ -1526,14 +1526,14 @@ namespace Google.Protobuf.TestProtos {
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     public static partial class Types {
       public enum NestedEnum {
-        NESTED_ENUM_UNSPECIFIED = 0,
-        FOO = 1,
-        BAR = 2,
-        BAZ = 3,
+        [pbr::OriginalName("NESTED_ENUM_UNSPECIFIED")] Unspecified = 0,
+        [pbr::OriginalName("FOO")] Foo = 1,
+        [pbr::OriginalName("BAR")] Bar = 2,
+        [pbr::OriginalName("BAZ")] Baz = 3,
         /// <summary>
         ///  Intentionally negative.
         /// </summary>
-        NEG = -1,
+        [pbr::OriginalName("NEG")] Neg = -1,
       }
 
       [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
@@ -2793,7 +2793,7 @@ namespace Google.Protobuf.TestProtos {
 
     /// <summary>Field number for the "EnumField" field.</summary>
     public const int EnumFieldFieldNumber = 3;
-    private global::Google.Protobuf.TestProtos.ForeignEnum enumField_ = global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED;
+    private global::Google.Protobuf.TestProtos.ForeignEnum enumField_ = 0;
     public global::Google.Protobuf.TestProtos.ForeignEnum EnumField {
       get { return enumField_; }
       set {
@@ -2873,7 +2873,7 @@ namespace Google.Protobuf.TestProtos {
       int hash = 1;
       if (PrimitiveField != 0) hash ^= PrimitiveField.GetHashCode();
       if (StringField.Length != 0) hash ^= StringField.GetHashCode();
-      if (EnumField != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) hash ^= EnumField.GetHashCode();
+      if (EnumField != 0) hash ^= EnumField.GetHashCode();
       if (messageField_ != null) hash ^= MessageField.GetHashCode();
       hash ^= repeatedPrimitiveField_.GetHashCode();
       hash ^= repeatedStringField_.GetHashCode();
@@ -2895,7 +2895,7 @@ namespace Google.Protobuf.TestProtos {
         output.WriteRawTag(18);
         output.WriteString(StringField);
       }
-      if (EnumField != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (EnumField != 0) {
         output.WriteRawTag(24);
         output.WriteEnum((int) EnumField);
       }
@@ -2917,7 +2917,7 @@ namespace Google.Protobuf.TestProtos {
       if (StringField.Length != 0) {
         size += 1 + pb::CodedOutputStream.ComputeStringSize(StringField);
       }
-      if (EnumField != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (EnumField != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) EnumField);
       }
       if (messageField_ != null) {
@@ -2940,7 +2940,7 @@ namespace Google.Protobuf.TestProtos {
       if (other.StringField.Length != 0) {
         StringField = other.StringField;
       }
-      if (other.EnumField != global::Google.Protobuf.TestProtos.ForeignEnum.FOREIGN_UNSPECIFIED) {
+      if (other.EnumField != 0) {
         EnumField = other.EnumField;
       }
       if (other.messageField_ != null) {
@@ -3370,7 +3370,7 @@ namespace Google.Protobuf.TestProtos {
 
     /// <summary>Field number for the "sparse_enum" field.</summary>
     public const int SparseEnumFieldNumber = 1;
-    private global::Google.Protobuf.TestProtos.TestSparseEnum sparseEnum_ = global::Google.Protobuf.TestProtos.TestSparseEnum.TEST_SPARSE_ENUM_UNSPECIFIED;
+    private global::Google.Protobuf.TestProtos.TestSparseEnum sparseEnum_ = 0;
     public global::Google.Protobuf.TestProtos.TestSparseEnum SparseEnum {
       get { return sparseEnum_; }
       set {
@@ -3395,7 +3395,7 @@ namespace Google.Protobuf.TestProtos {
 
     public override int GetHashCode() {
       int hash = 1;
-      if (SparseEnum != global::Google.Protobuf.TestProtos.TestSparseEnum.TEST_SPARSE_ENUM_UNSPECIFIED) hash ^= SparseEnum.GetHashCode();
+      if (SparseEnum != 0) hash ^= SparseEnum.GetHashCode();
       return hash;
     }
 
@@ -3404,7 +3404,7 @@ namespace Google.Protobuf.TestProtos {
     }
 
     public void WriteTo(pb::CodedOutputStream output) {
-      if (SparseEnum != global::Google.Protobuf.TestProtos.TestSparseEnum.TEST_SPARSE_ENUM_UNSPECIFIED) {
+      if (SparseEnum != 0) {
         output.WriteRawTag(8);
         output.WriteEnum((int) SparseEnum);
       }
@@ -3412,7 +3412,7 @@ namespace Google.Protobuf.TestProtos {
 
     public int CalculateSize() {
       int size = 0;
-      if (SparseEnum != global::Google.Protobuf.TestProtos.TestSparseEnum.TEST_SPARSE_ENUM_UNSPECIFIED) {
+      if (SparseEnum != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) SparseEnum);
       }
       return size;
@@ -3422,7 +3422,7 @@ namespace Google.Protobuf.TestProtos {
       if (other == null) {
         return;
       }
-      if (other.SparseEnum != global::Google.Protobuf.TestProtos.TestSparseEnum.TEST_SPARSE_ENUM_UNSPECIFIED) {
+      if (other.SparseEnum != 0) {
         SparseEnum = other.SparseEnum;
       }
     }
diff --git a/csharp/src/Google.Protobuf/Google.Protobuf.csproj b/csharp/src/Google.Protobuf/Google.Protobuf.csproj
index ef524baf..5557612a 100644
--- a/csharp/src/Google.Protobuf/Google.Protobuf.csproj
+++ b/csharp/src/Google.Protobuf/Google.Protobuf.csproj
@@ -117,6 +117,7 @@
     <Compile Include="Reflection\MethodDescriptor.cs" />
     <Compile Include="Reflection\OneofAccessor.cs" />
     <Compile Include="Reflection\OneofDescriptor.cs" />
+    <Compile Include="Reflection\OriginalNameAttribute.cs" />
     <Compile Include="Reflection\PackageDescriptor.cs" />
     <Compile Include="Reflection\PartialClasses.cs" />
     <Compile Include="Reflection\ReflectionUtil.cs" />
diff --git a/csharp/src/Google.Protobuf/Google.Protobuf.nuspec b/csharp/src/Google.Protobuf/Google.Protobuf.nuspec
index f51bc89a..2892b8bf 100644
--- a/csharp/src/Google.Protobuf/Google.Protobuf.nuspec
+++ b/csharp/src/Google.Protobuf/Google.Protobuf.nuspec
@@ -33,10 +33,12 @@
         <dependency id="System.Linq.Expressions" version="4.0.0" />
         <dependency id="System.ObjectModel" version="4.0.0" />
         <dependency id="System.Reflection" version="4.0.0" />
+        <dependency id="System.Reflection.Extensions" version="4.0.0" />
         <dependency id="System.Runtime" version="4.0.0" />
         <dependency id="System.Runtime.Extensions" version="4.0.0" />
         <dependency id="System.Text.Encoding" version="4.0.0" />
         <dependency id="System.Text.RegularExpressions" version="4.0.0" />
+        <dependency id="System.Threading" version="4.0.0" />
       </group>
     </dependencies>
   </metadata>
diff --git a/csharp/src/Google.Protobuf/JsonFormatter.cs b/csharp/src/Google.Protobuf/JsonFormatter.cs
index cbd9366c..73a4f64b 100644
--- a/csharp/src/Google.Protobuf/JsonFormatter.cs
+++ b/csharp/src/Google.Protobuf/JsonFormatter.cs
@@ -39,6 +39,7 @@ using Google.Protobuf.WellKnownTypes;
 using System.IO;
 using System.Linq;
 using System.Collections.Generic;
+using System.Reflection;
 
 namespace Google.Protobuf
 {
@@ -420,9 +421,10 @@ namespace Google.Protobuf
             }
             else if (value is System.Enum)
             {
-                if (System.Enum.IsDefined(value.GetType(), value))
+                string name = OriginalEnumValueHelper.GetOriginalName(value);
+                if (name != null)
                 {
-                    WriteString(writer, value.ToString());
+                    WriteString(writer, name);
                 }
                 else
                 {
@@ -877,5 +879,44 @@ namespace Google.Protobuf
                 TypeRegistry = ProtoPreconditions.CheckNotNull(typeRegistry, nameof(typeRegistry));
             }
         }
+
+        // Effectively a cache of mapping from enum values to the original name as specified in the proto file,
+        // fetched by reflection.
+        // The need for this is unfortunate, as is its unbounded size, but realistically it shouldn't cause issues.
+        private static class OriginalEnumValueHelper
+        {
+            // TODO: In the future we might want to use ConcurrentDictionary, at the point where all
+            // the platforms we target have it.
+            private static readonly Dictionary<System.Type, Dictionary<object, string>> dictionaries
+                = new Dictionary<System.Type, Dictionary<object, string>>();
+            
+            internal static string GetOriginalName(object value)
+            {
+                var enumType = value.GetType();
+                Dictionary<object, string> nameMapping;
+                lock (dictionaries)
+                {
+                    if (!dictionaries.TryGetValue(enumType, out nameMapping))
+                    {
+                        nameMapping = GetNameMapping(enumType);
+                        dictionaries[enumType] = nameMapping;
+                    }
+                }
+
+                string originalName;
+                // If this returns false, originalName will be null, which is what we want.
+                nameMapping.TryGetValue(value, out originalName);
+                return originalName;
+            }
+
+            private static Dictionary<object, string> GetNameMapping(System.Type enumType) =>
+                enumType.GetTypeInfo().DeclaredFields
+                    .Where(f => f.IsStatic)
+                    .ToDictionary(f => f.GetValue(null),
+                                  f => f.GetCustomAttributes<OriginalNameAttribute>()
+                                        .FirstOrDefault()
+                                        // If the attribute hasn't been applied, fall back to the name of the field.
+                                        ?.Name ?? f.Name);
+        }
     }
 }
diff --git a/csharp/src/Google.Protobuf/Reflection/Descriptor.cs b/csharp/src/Google.Protobuf/Reflection/Descriptor.cs
index 7de7b5fc..fa138dfe 100644
--- a/csharp/src/Google.Protobuf/Reflection/Descriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/Descriptor.cs
@@ -80,7 +80,7 @@ namespace Google.Protobuf.Reflection {
             "EhMKC291dHB1dF90eXBlGAMgASgJEi8KB29wdGlvbnMYBCABKAsyHi5nb29n",
             "bGUucHJvdG9idWYuTWV0aG9kT3B0aW9ucxIfChBjbGllbnRfc3RyZWFtaW5n",
             "GAUgASgIOgVmYWxzZRIfChBzZXJ2ZXJfc3RyZWFtaW5nGAYgASgIOgVmYWxz",
-            "ZSKuBQoLRmlsZU9wdGlvbnMSFAoMamF2YV9wYWNrYWdlGAEgASgJEhwKFGph",
+            "ZSKHBQoLRmlsZU9wdGlvbnMSFAoMamF2YV9wYWNrYWdlGAEgASgJEhwKFGph",
             "dmFfb3V0ZXJfY2xhc3NuYW1lGAggASgJEiIKE2phdmFfbXVsdGlwbGVfZmls",
             "ZXMYCiABKAg6BWZhbHNlEiwKHWphdmFfZ2VuZXJhdGVfZXF1YWxzX2FuZF9o",
             "YXNoGBQgASgIOgVmYWxzZRIlChZqYXZhX3N0cmluZ19jaGVja191dGY4GBsg",
@@ -91,54 +91,53 @@ namespace Google.Protobuf.Reflection {
             "cHlfZ2VuZXJpY19zZXJ2aWNlcxgSIAEoCDoFZmFsc2USGQoKZGVwcmVjYXRl",
             "ZBgXIAEoCDoFZmFsc2USHwoQY2NfZW5hYmxlX2FyZW5hcxgfIAEoCDoFZmFs",
             "c2USGQoRb2JqY19jbGFzc19wcmVmaXgYJCABKAkSGAoQY3NoYXJwX25hbWVz",
-            "cGFjZRglIAEoCRIrCh9qYXZhbmFub191c2VfZGVwcmVjYXRlZF9wYWNrYWdl",
-            "GCYgASgIQgIYARJDChR1bmludGVycHJldGVkX29wdGlvbhjnByADKAsyJC5n",
+            "cGFjZRglIAEoCRJDChR1bmludGVycHJldGVkX29wdGlvbhjnByADKAsyJC5n",
             "b29nbGUucHJvdG9idWYuVW5pbnRlcnByZXRlZE9wdGlvbiI6CgxPcHRpbWl6",
             "ZU1vZGUSCQoFU1BFRUQQARINCglDT0RFX1NJWkUQAhIQCgxMSVRFX1JVTlRJ",
-            "TUUQAyoJCOgHEICAgIACIuYBCg5NZXNzYWdlT3B0aW9ucxImChdtZXNzYWdl",
-            "X3NldF93aXJlX2Zvcm1hdBgBIAEoCDoFZmFsc2USLgofbm9fc3RhbmRhcmRf",
-            "ZGVzY3JpcHRvcl9hY2Nlc3NvchgCIAEoCDoFZmFsc2USGQoKZGVwcmVjYXRl",
-            "ZBgDIAEoCDoFZmFsc2USEQoJbWFwX2VudHJ5GAcgASgIEkMKFHVuaW50ZXJw",
-            "cmV0ZWRfb3B0aW9uGOcHIAMoCzIkLmdvb2dsZS5wcm90b2J1Zi5VbmludGVy",
-            "cHJldGVkT3B0aW9uKgkI6AcQgICAgAIimAMKDEZpZWxkT3B0aW9ucxI6CgVj",
-            "dHlwZRgBIAEoDjIjLmdvb2dsZS5wcm90b2J1Zi5GaWVsZE9wdGlvbnMuQ1R5",
-            "cGU6BlNUUklORxIOCgZwYWNrZWQYAiABKAgSPwoGanN0eXBlGAYgASgOMiQu",
-            "Z29vZ2xlLnByb3RvYnVmLkZpZWxkT3B0aW9ucy5KU1R5cGU6CUpTX05PUk1B",
-            "TBITCgRsYXp5GAUgASgIOgVmYWxzZRIZCgpkZXByZWNhdGVkGAMgASgIOgVm",
-            "YWxzZRITCgR3ZWFrGAogASgIOgVmYWxzZRJDChR1bmludGVycHJldGVkX29w",
+            "TUUQAyoJCOgHEICAgIACSgQIJhAnIuYBCg5NZXNzYWdlT3B0aW9ucxImChdt",
+            "ZXNzYWdlX3NldF93aXJlX2Zvcm1hdBgBIAEoCDoFZmFsc2USLgofbm9fc3Rh",
+            "bmRhcmRfZGVzY3JpcHRvcl9hY2Nlc3NvchgCIAEoCDoFZmFsc2USGQoKZGVw",
+            "cmVjYXRlZBgDIAEoCDoFZmFsc2USEQoJbWFwX2VudHJ5GAcgASgIEkMKFHVu",
+            "aW50ZXJwcmV0ZWRfb3B0aW9uGOcHIAMoCzIkLmdvb2dsZS5wcm90b2J1Zi5V",
+            "bmludGVycHJldGVkT3B0aW9uKgkI6AcQgICAgAIimAMKDEZpZWxkT3B0aW9u",
+            "cxI6CgVjdHlwZRgBIAEoDjIjLmdvb2dsZS5wcm90b2J1Zi5GaWVsZE9wdGlv",
+            "bnMuQ1R5cGU6BlNUUklORxIOCgZwYWNrZWQYAiABKAgSPwoGanN0eXBlGAYg",
+            "ASgOMiQuZ29vZ2xlLnByb3RvYnVmLkZpZWxkT3B0aW9ucy5KU1R5cGU6CUpT",
+            "X05PUk1BTBITCgRsYXp5GAUgASgIOgVmYWxzZRIZCgpkZXByZWNhdGVkGAMg",
+            "ASgIOgVmYWxzZRITCgR3ZWFrGAogASgIOgVmYWxzZRJDChR1bmludGVycHJl",
+            "dGVkX29wdGlvbhjnByADKAsyJC5nb29nbGUucHJvdG9idWYuVW5pbnRlcnBy",
+            "ZXRlZE9wdGlvbiIvCgVDVHlwZRIKCgZTVFJJTkcQABIICgRDT1JEEAESEAoM",
+            "U1RSSU5HX1BJRUNFEAIiNQoGSlNUeXBlEg0KCUpTX05PUk1BTBAAEg0KCUpT",
+            "X1NUUklORxABEg0KCUpTX05VTUJFUhACKgkI6AcQgICAgAIijQEKC0VudW1P",
+            "cHRpb25zEhMKC2FsbG93X2FsaWFzGAIgASgIEhkKCmRlcHJlY2F0ZWQYAyAB",
+            "KAg6BWZhbHNlEkMKFHVuaW50ZXJwcmV0ZWRfb3B0aW9uGOcHIAMoCzIkLmdv",
+            "b2dsZS5wcm90b2J1Zi5VbmludGVycHJldGVkT3B0aW9uKgkI6AcQgICAgAIi",
+            "fQoQRW51bVZhbHVlT3B0aW9ucxIZCgpkZXByZWNhdGVkGAEgASgIOgVmYWxz",
+            "ZRJDChR1bmludGVycHJldGVkX29wdGlvbhjnByADKAsyJC5nb29nbGUucHJv",
+            "dG9idWYuVW5pbnRlcnByZXRlZE9wdGlvbioJCOgHEICAgIACInsKDlNlcnZp",
+            "Y2VPcHRpb25zEhkKCmRlcHJlY2F0ZWQYISABKAg6BWZhbHNlEkMKFHVuaW50",
+            "ZXJwcmV0ZWRfb3B0aW9uGOcHIAMoCzIkLmdvb2dsZS5wcm90b2J1Zi5Vbmlu",
+            "dGVycHJldGVkT3B0aW9uKgkI6AcQgICAgAIiegoNTWV0aG9kT3B0aW9ucxIZ",
+            "CgpkZXByZWNhdGVkGCEgASgIOgVmYWxzZRJDChR1bmludGVycHJldGVkX29w",
             "dGlvbhjnByADKAsyJC5nb29nbGUucHJvdG9idWYuVW5pbnRlcnByZXRlZE9w",
-            "dGlvbiIvCgVDVHlwZRIKCgZTVFJJTkcQABIICgRDT1JEEAESEAoMU1RSSU5H",
-            "X1BJRUNFEAIiNQoGSlNUeXBlEg0KCUpTX05PUk1BTBAAEg0KCUpTX1NUUklO",
-            "RxABEg0KCUpTX05VTUJFUhACKgkI6AcQgICAgAIijQEKC0VudW1PcHRpb25z",
-            "EhMKC2FsbG93X2FsaWFzGAIgASgIEhkKCmRlcHJlY2F0ZWQYAyABKAg6BWZh",
-            "bHNlEkMKFHVuaW50ZXJwcmV0ZWRfb3B0aW9uGOcHIAMoCzIkLmdvb2dsZS5w",
-            "cm90b2J1Zi5VbmludGVycHJldGVkT3B0aW9uKgkI6AcQgICAgAIifQoQRW51",
-            "bVZhbHVlT3B0aW9ucxIZCgpkZXByZWNhdGVkGAEgASgIOgVmYWxzZRJDChR1",
-            "bmludGVycHJldGVkX29wdGlvbhjnByADKAsyJC5nb29nbGUucHJvdG9idWYu",
-            "VW5pbnRlcnByZXRlZE9wdGlvbioJCOgHEICAgIACInsKDlNlcnZpY2VPcHRp",
-            "b25zEhkKCmRlcHJlY2F0ZWQYISABKAg6BWZhbHNlEkMKFHVuaW50ZXJwcmV0",
-            "ZWRfb3B0aW9uGOcHIAMoCzIkLmdvb2dsZS5wcm90b2J1Zi5VbmludGVycHJl",
-            "dGVkT3B0aW9uKgkI6AcQgICAgAIiegoNTWV0aG9kT3B0aW9ucxIZCgpkZXBy",
-            "ZWNhdGVkGCEgASgIOgVmYWxzZRJDChR1bmludGVycHJldGVkX29wdGlvbhjn",
-            "ByADKAsyJC5nb29nbGUucHJvdG9idWYuVW5pbnRlcnByZXRlZE9wdGlvbioJ",
-            "COgHEICAgIACIp4CChNVbmludGVycHJldGVkT3B0aW9uEjsKBG5hbWUYAiAD",
-            "KAsyLS5nb29nbGUucHJvdG9idWYuVW5pbnRlcnByZXRlZE9wdGlvbi5OYW1l",
-            "UGFydBIYChBpZGVudGlmaWVyX3ZhbHVlGAMgASgJEhoKEnBvc2l0aXZlX2lu",
-            "dF92YWx1ZRgEIAEoBBIaChJuZWdhdGl2ZV9pbnRfdmFsdWUYBSABKAMSFAoM",
-            "ZG91YmxlX3ZhbHVlGAYgASgBEhQKDHN0cmluZ192YWx1ZRgHIAEoDBIXCg9h",
-            "Z2dyZWdhdGVfdmFsdWUYCCABKAkaMwoITmFtZVBhcnQSEQoJbmFtZV9wYXJ0",
-            "GAEgAigJEhQKDGlzX2V4dGVuc2lvbhgCIAIoCCLVAQoOU291cmNlQ29kZUlu",
-            "Zm8SOgoIbG9jYXRpb24YASADKAsyKC5nb29nbGUucHJvdG9idWYuU291cmNl",
-            "Q29kZUluZm8uTG9jYXRpb24ahgEKCExvY2F0aW9uEhAKBHBhdGgYASADKAVC",
-            "AhABEhAKBHNwYW4YAiADKAVCAhABEhgKEGxlYWRpbmdfY29tbWVudHMYAyAB",
-            "KAkSGQoRdHJhaWxpbmdfY29tbWVudHMYBCABKAkSIQoZbGVhZGluZ19kZXRh",
-            "Y2hlZF9jb21tZW50cxgGIAMoCSKnAQoRR2VuZXJhdGVkQ29kZUluZm8SQQoK",
-            "YW5ub3RhdGlvbhgBIAMoCzItLmdvb2dsZS5wcm90b2J1Zi5HZW5lcmF0ZWRD",
-            "b2RlSW5mby5Bbm5vdGF0aW9uGk8KCkFubm90YXRpb24SEAoEcGF0aBgBIAMo",
-            "BUICEAESEwoLc291cmNlX2ZpbGUYAiABKAkSDQoFYmVnaW4YAyABKAUSCwoD",
-            "ZW5kGAQgASgFQlgKE2NvbS5nb29nbGUucHJvdG9idWZCEERlc2NyaXB0b3JQ",
-            "cm90b3NIAVoKZGVzY3JpcHRvcqICA0dQQqoCGkdvb2dsZS5Qcm90b2J1Zi5S",
-            "ZWZsZWN0aW9u"));
+            "dGlvbioJCOgHEICAgIACIp4CChNVbmludGVycHJldGVkT3B0aW9uEjsKBG5h",
+            "bWUYAiADKAsyLS5nb29nbGUucHJvdG9idWYuVW5pbnRlcnByZXRlZE9wdGlv",
+            "bi5OYW1lUGFydBIYChBpZGVudGlmaWVyX3ZhbHVlGAMgASgJEhoKEnBvc2l0",
+            "aXZlX2ludF92YWx1ZRgEIAEoBBIaChJuZWdhdGl2ZV9pbnRfdmFsdWUYBSAB",
+            "KAMSFAoMZG91YmxlX3ZhbHVlGAYgASgBEhQKDHN0cmluZ192YWx1ZRgHIAEo",
+            "DBIXCg9hZ2dyZWdhdGVfdmFsdWUYCCABKAkaMwoITmFtZVBhcnQSEQoJbmFt",
+            "ZV9wYXJ0GAEgAigJEhQKDGlzX2V4dGVuc2lvbhgCIAIoCCLVAQoOU291cmNl",
+            "Q29kZUluZm8SOgoIbG9jYXRpb24YASADKAsyKC5nb29nbGUucHJvdG9idWYu",
+            "U291cmNlQ29kZUluZm8uTG9jYXRpb24ahgEKCExvY2F0aW9uEhAKBHBhdGgY",
+            "ASADKAVCAhABEhAKBHNwYW4YAiADKAVCAhABEhgKEGxlYWRpbmdfY29tbWVu",
+            "dHMYAyABKAkSGQoRdHJhaWxpbmdfY29tbWVudHMYBCABKAkSIQoZbGVhZGlu",
+            "Z19kZXRhY2hlZF9jb21tZW50cxgGIAMoCSKnAQoRR2VuZXJhdGVkQ29kZUlu",
+            "Zm8SQQoKYW5ub3RhdGlvbhgBIAMoCzItLmdvb2dsZS5wcm90b2J1Zi5HZW5l",
+            "cmF0ZWRDb2RlSW5mby5Bbm5vdGF0aW9uGk8KCkFubm90YXRpb24SEAoEcGF0",
+            "aBgBIAMoBUICEAESEwoLc291cmNlX2ZpbGUYAiABKAkSDQoFYmVnaW4YAyAB",
+            "KAUSCwoDZW5kGAQgASgFQlgKE2NvbS5nb29nbGUucHJvdG9idWZCEERlc2Ny",
+            "aXB0b3JQcm90b3NIAVoKZGVzY3JpcHRvcqICA0dQQqoCGkdvb2dsZS5Qcm90",
+            "b2J1Zi5SZWZsZWN0aW9u"));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
@@ -152,7 +151,7 @@ namespace Google.Protobuf.Reflection {
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.EnumValueDescriptorProto), global::Google.Protobuf.Reflection.EnumValueDescriptorProto.Parser, new[]{ "Name", "Number", "Options" }, null, null, null),
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.ServiceDescriptorProto), global::Google.Protobuf.Reflection.ServiceDescriptorProto.Parser, new[]{ "Name", "Method", "Options" }, null, null, null),
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.MethodDescriptorProto), global::Google.Protobuf.Reflection.MethodDescriptorProto.Parser, new[]{ "Name", "InputType", "OutputType", "Options", "ClientStreaming", "ServerStreaming" }, null, null, null),
-            new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.FileOptions), global::Google.Protobuf.Reflection.FileOptions.Parser, new[]{ "JavaPackage", "JavaOuterClassname", "JavaMultipleFiles", "JavaGenerateEqualsAndHash", "JavaStringCheckUtf8", "OptimizeFor", "GoPackage", "CcGenericServices", "JavaGenericServices", "PyGenericServices", "Deprecated", "CcEnableArenas", "ObjcClassPrefix", "CsharpNamespace", "JavananoUseDeprecatedPackage", "UninterpretedOption" }, null, new[]{ typeof(global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode) }, null),
+            new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.FileOptions), global::Google.Protobuf.Reflection.FileOptions.Parser, new[]{ "JavaPackage", "JavaOuterClassname", "JavaMultipleFiles", "JavaGenerateEqualsAndHash", "JavaStringCheckUtf8", "OptimizeFor", "GoPackage", "CcGenericServices", "JavaGenericServices", "PyGenericServices", "Deprecated", "CcEnableArenas", "ObjcClassPrefix", "CsharpNamespace", "UninterpretedOption" }, null, new[]{ typeof(global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode) }, null),
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.MessageOptions), global::Google.Protobuf.Reflection.MessageOptions.Parser, new[]{ "MessageSetWireFormat", "NoStandardDescriptorAccessor", "Deprecated", "MapEntry", "UninterpretedOption" }, null, null, null),
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.FieldOptions), global::Google.Protobuf.Reflection.FieldOptions.Parser, new[]{ "Ctype", "Packed", "Jstype", "Lazy", "Deprecated", "Weak", "UninterpretedOption" }, null, new[]{ typeof(global::Google.Protobuf.Reflection.FieldOptions.Types.CType), typeof(global::Google.Protobuf.Reflection.FieldOptions.Types.JSType) }, null),
             new pbr::GeneratedClrTypeInfo(typeof(global::Google.Protobuf.Reflection.EnumOptions), global::Google.Protobuf.Reflection.EnumOptions.Parser, new[]{ "AllowAlias", "Deprecated", "UninterpretedOption" }, null, null, null),
@@ -1291,7 +1290,7 @@ namespace Google.Protobuf.Reflection {
 
     /// <summary>Field number for the "label" field.</summary>
     public const int LabelFieldNumber = 4;
-    private global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label label_ = global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label.LABEL_OPTIONAL;
+    private global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label label_ = 0;
     public global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label Label {
       get { return label_; }
       set {
@@ -1301,7 +1300,7 @@ namespace Google.Protobuf.Reflection {
 
     /// <summary>Field number for the "type" field.</summary>
     public const int TypeFieldNumber = 5;
-    private global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type type_ = global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type.TYPE_DOUBLE;
+    private global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type type_ = 0;
     /// <summary>
     ///  If type_name is set, this need not be set.  If both this and type_name
     ///  are set, this must be one of TYPE_ENUM, TYPE_MESSAGE or TYPE_GROUP.
@@ -1429,8 +1428,8 @@ namespace Google.Protobuf.Reflection {
       int hash = 1;
       if (Name.Length != 0) hash ^= Name.GetHashCode();
       if (Number != 0) hash ^= Number.GetHashCode();
-      if (Label != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label.LABEL_OPTIONAL) hash ^= Label.GetHashCode();
-      if (Type != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type.TYPE_DOUBLE) hash ^= Type.GetHashCode();
+      if (Label != 0) hash ^= Label.GetHashCode();
+      if (Type != 0) hash ^= Type.GetHashCode();
       if (TypeName.Length != 0) hash ^= TypeName.GetHashCode();
       if (Extendee.Length != 0) hash ^= Extendee.GetHashCode();
       if (DefaultValue.Length != 0) hash ^= DefaultValue.GetHashCode();
@@ -1457,11 +1456,11 @@ namespace Google.Protobuf.Reflection {
         output.WriteRawTag(24);
         output.WriteInt32(Number);
       }
-      if (Label != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label.LABEL_OPTIONAL) {
+      if (Label != 0) {
         output.WriteRawTag(32);
         output.WriteEnum((int) Label);
       }
-      if (Type != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type.TYPE_DOUBLE) {
+      if (Type != 0) {
         output.WriteRawTag(40);
         output.WriteEnum((int) Type);
       }
@@ -1495,10 +1494,10 @@ namespace Google.Protobuf.Reflection {
       if (Number != 0) {
         size += 1 + pb::CodedOutputStream.ComputeInt32Size(Number);
       }
-      if (Label != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label.LABEL_OPTIONAL) {
+      if (Label != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Label);
       }
-      if (Type != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type.TYPE_DOUBLE) {
+      if (Type != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Type);
       }
       if (TypeName.Length != 0) {
@@ -1532,10 +1531,10 @@ namespace Google.Protobuf.Reflection {
       if (other.Number != 0) {
         Number = other.Number;
       }
-      if (other.Label != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Label.LABEL_OPTIONAL) {
+      if (other.Label != 0) {
         Label = other.Label;
       }
-      if (other.Type != global::Google.Protobuf.Reflection.FieldDescriptorProto.Types.Type.TYPE_DOUBLE) {
+      if (other.Type != 0) {
         Type = other.Type;
       }
       if (other.TypeName.Length != 0) {
@@ -1624,59 +1623,59 @@ namespace Google.Protobuf.Reflection {
         ///  0 is reserved for errors.
         ///  Order is weird for historical reasons.
         /// </summary>
-        TYPE_DOUBLE = 1,
-        TYPE_FLOAT = 2,
+        [pbr::OriginalName("TYPE_DOUBLE")] Double = 1,
+        [pbr::OriginalName("TYPE_FLOAT")] Float = 2,
         /// <summary>
         ///  Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT64 if
         ///  negative values are likely.
         /// </summary>
-        TYPE_INT64 = 3,
-        TYPE_UINT64 = 4,
+        [pbr::OriginalName("TYPE_INT64")] Int64 = 3,
+        [pbr::OriginalName("TYPE_UINT64")] Uint64 = 4,
         /// <summary>
         ///  Not ZigZag encoded.  Negative numbers take 10 bytes.  Use TYPE_SINT32 if
         ///  negative values are likely.
         /// </summary>
-        TYPE_INT32 = 5,
-        TYPE_FIXED64 = 6,
-        TYPE_FIXED32 = 7,
-        TYPE_BOOL = 8,
-        TYPE_STRING = 9,
+        [pbr::OriginalName("TYPE_INT32")] Int32 = 5,
+        [pbr::OriginalName("TYPE_FIXED64")] Fixed64 = 6,
+        [pbr::OriginalName("TYPE_FIXED32")] Fixed32 = 7,
+        [pbr::OriginalName("TYPE_BOOL")] Bool = 8,
+        [pbr::OriginalName("TYPE_STRING")] String = 9,
         /// <summary>
         ///  Tag-delimited aggregate.
         /// </summary>
-        TYPE_GROUP = 10,
+        [pbr::OriginalName("TYPE_GROUP")] Group = 10,
         /// <summary>
         ///  Length-delimited aggregate.
         /// </summary>
-        TYPE_MESSAGE = 11,
+        [pbr::OriginalName("TYPE_MESSAGE")] Message = 11,
         /// <summary>
         ///  New in version 2.
         /// </summary>
-        TYPE_BYTES = 12,
-        TYPE_UINT32 = 13,
-        TYPE_ENUM = 14,
-        TYPE_SFIXED32 = 15,
-        TYPE_SFIXED64 = 16,
+        [pbr::OriginalName("TYPE_BYTES")] Bytes = 12,
+        [pbr::OriginalName("TYPE_UINT32")] Uint32 = 13,
+        [pbr::OriginalName("TYPE_ENUM")] Enum = 14,
+        [pbr::OriginalName("TYPE_SFIXED32")] Sfixed32 = 15,
+        [pbr::OriginalName("TYPE_SFIXED64")] Sfixed64 = 16,
         /// <summary>
         ///  Uses ZigZag encoding.
         /// </summary>
-        TYPE_SINT32 = 17,
+        [pbr::OriginalName("TYPE_SINT32")] Sint32 = 17,
         /// <summary>
         ///  Uses ZigZag encoding.
         /// </summary>
-        TYPE_SINT64 = 18,
+        [pbr::OriginalName("TYPE_SINT64")] Sint64 = 18,
       }
 
       internal enum Label {
         /// <summary>
         ///  0 is reserved for errors
         /// </summary>
-        LABEL_OPTIONAL = 1,
-        LABEL_REQUIRED = 2,
+        [pbr::OriginalName("LABEL_OPTIONAL")] Optional = 1,
+        [pbr::OriginalName("LABEL_REQUIRED")] Required = 2,
         /// <summary>
         ///  TODO(sanjay): Should we add LABEL_MAP?
         /// </summary>
-        LABEL_REPEATED = 3,
+        [pbr::OriginalName("LABEL_REPEATED")] Repeated = 3,
       }
 
     }
@@ -2563,7 +2562,6 @@ namespace Google.Protobuf.Reflection {
       ccEnableArenas_ = other.ccEnableArenas_;
       objcClassPrefix_ = other.objcClassPrefix_;
       csharpNamespace_ = other.csharpNamespace_;
-      javananoUseDeprecatedPackage_ = other.javananoUseDeprecatedPackage_;
       uninterpretedOption_ = other.uninterpretedOption_.Clone();
     }
 
@@ -2666,7 +2664,7 @@ namespace Google.Protobuf.Reflection {
 
     /// <summary>Field number for the "optimize_for" field.</summary>
     public const int OptimizeForFieldNumber = 9;
-    private global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode optimizeFor_ = global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode.SPEED;
+    private global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode optimizeFor_ = 0;
     public global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode OptimizeFor {
       get { return optimizeFor_; }
       set {
@@ -2790,21 +2788,6 @@ namespace Google.Protobuf.Reflection {
       }
     }
 
-    /// <summary>Field number for the "javanano_use_deprecated_package" field.</summary>
-    public const int JavananoUseDeprecatedPackageFieldNumber = 38;
-    private bool javananoUseDeprecatedPackage_;
-    /// <summary>
-    ///  Whether the nano proto compiler should generate in the deprecated non-nano
-    ///  suffixed package.
-    /// </summary>
-    [global::System.ObsoleteAttribute()]
-    public bool JavananoUseDeprecatedPackage {
-      get { return javananoUseDeprecatedPackage_; }
-      set {
-        javananoUseDeprecatedPackage_ = value;
-      }
-    }
-
     /// <summary>Field number for the "uninterpreted_option" field.</summary>
     public const int UninterpretedOptionFieldNumber = 999;
     private static readonly pb::FieldCodec<global::Google.Protobuf.Reflection.UninterpretedOption> _repeated_uninterpretedOption_codec
@@ -2842,7 +2825,6 @@ namespace Google.Protobuf.Reflection {
       if (CcEnableArenas != other.CcEnableArenas) return false;
       if (ObjcClassPrefix != other.ObjcClassPrefix) return false;
       if (CsharpNamespace != other.CsharpNamespace) return false;
-      if (JavananoUseDeprecatedPackage != other.JavananoUseDeprecatedPackage) return false;
       if(!uninterpretedOption_.Equals(other.uninterpretedOption_)) return false;
       return true;
     }
@@ -2854,7 +2836,7 @@ namespace Google.Protobuf.Reflection {
       if (JavaMultipleFiles != false) hash ^= JavaMultipleFiles.GetHashCode();
       if (JavaGenerateEqualsAndHash != false) hash ^= JavaGenerateEqualsAndHash.GetHashCode();
       if (JavaStringCheckUtf8 != false) hash ^= JavaStringCheckUtf8.GetHashCode();
-      if (OptimizeFor != global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode.SPEED) hash ^= OptimizeFor.GetHashCode();
+      if (OptimizeFor != 0) hash ^= OptimizeFor.GetHashCode();
       if (GoPackage.Length != 0) hash ^= GoPackage.GetHashCode();
       if (CcGenericServices != false) hash ^= CcGenericServices.GetHashCode();
       if (JavaGenericServices != false) hash ^= JavaGenericServices.GetHashCode();
@@ -2863,7 +2845,6 @@ namespace Google.Protobuf.Reflection {
       if (CcEnableArenas != false) hash ^= CcEnableArenas.GetHashCode();
       if (ObjcClassPrefix.Length != 0) hash ^= ObjcClassPrefix.GetHashCode();
       if (CsharpNamespace.Length != 0) hash ^= CsharpNamespace.GetHashCode();
-      if (JavananoUseDeprecatedPackage != false) hash ^= JavananoUseDeprecatedPackage.GetHashCode();
       hash ^= uninterpretedOption_.GetHashCode();
       return hash;
     }
@@ -2881,7 +2862,7 @@ namespace Google.Protobuf.Reflection {
         output.WriteRawTag(66);
         output.WriteString(JavaOuterClassname);
       }
-      if (OptimizeFor != global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode.SPEED) {
+      if (OptimizeFor != 0) {
         output.WriteRawTag(72);
         output.WriteEnum((int) OptimizeFor);
       }
@@ -2929,10 +2910,6 @@ namespace Google.Protobuf.Reflection {
         output.WriteRawTag(170, 2);
         output.WriteString(CsharpNamespace);
       }
-      if (JavananoUseDeprecatedPackage != false) {
-        output.WriteRawTag(176, 2);
-        output.WriteBool(JavananoUseDeprecatedPackage);
-      }
       uninterpretedOption_.WriteTo(output, _repeated_uninterpretedOption_codec);
     }
 
@@ -2953,7 +2930,7 @@ namespace Google.Protobuf.Reflection {
       if (JavaStringCheckUtf8 != false) {
         size += 2 + 1;
       }
-      if (OptimizeFor != global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode.SPEED) {
+      if (OptimizeFor != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) OptimizeFor);
       }
       if (GoPackage.Length != 0) {
@@ -2980,9 +2957,6 @@ namespace Google.Protobuf.Reflection {
       if (CsharpNamespace.Length != 0) {
         size += 2 + pb::CodedOutputStream.ComputeStringSize(CsharpNamespace);
       }
-      if (JavananoUseDeprecatedPackage != false) {
-        size += 2 + 1;
-      }
       size += uninterpretedOption_.CalculateSize(_repeated_uninterpretedOption_codec);
       return size;
     }
@@ -3006,7 +2980,7 @@ namespace Google.Protobuf.Reflection {
       if (other.JavaStringCheckUtf8 != false) {
         JavaStringCheckUtf8 = other.JavaStringCheckUtf8;
       }
-      if (other.OptimizeFor != global::Google.Protobuf.Reflection.FileOptions.Types.OptimizeMode.SPEED) {
+      if (other.OptimizeFor != 0) {
         OptimizeFor = other.OptimizeFor;
       }
       if (other.GoPackage.Length != 0) {
@@ -3033,9 +3007,6 @@ namespace Google.Protobuf.Reflection {
       if (other.CsharpNamespace.Length != 0) {
         CsharpNamespace = other.CsharpNamespace;
       }
-      if (other.JavananoUseDeprecatedPackage != false) {
-        JavananoUseDeprecatedPackage = other.JavananoUseDeprecatedPackage;
-      }
       uninterpretedOption_.Add(other.uninterpretedOption_);
     }
 
@@ -3102,10 +3073,6 @@ namespace Google.Protobuf.Reflection {
             CsharpNamespace = input.ReadString();
             break;
           }
-          case 304: {
-            JavananoUseDeprecatedPackage = input.ReadBool();
-            break;
-          }
           case 7994: {
             uninterpretedOption_.AddEntriesFrom(input, _repeated_uninterpretedOption_codec);
             break;
@@ -3125,15 +3092,15 @@ namespace Google.Protobuf.Reflection {
         /// <summary>
         ///  Generate complete code for parsing, serialization,
         /// </summary>
-        SPEED = 1,
+        [pbr::OriginalName("SPEED")] Speed = 1,
         /// <summary>
         ///  etc.
         /// </summary>
-        CODE_SIZE = 2,
+        [pbr::OriginalName("CODE_SIZE")] CodeSize = 2,
         /// <summary>
         ///  Generate code using MessageLite and the lite runtime.
         /// </summary>
-        LITE_RUNTIME = 3,
+        [pbr::OriginalName("LITE_RUNTIME")] LiteRuntime = 3,
       }
 
     }
@@ -3436,7 +3403,7 @@ namespace Google.Protobuf.Reflection {
 
     /// <summary>Field number for the "ctype" field.</summary>
     public const int CtypeFieldNumber = 1;
-    private global::Google.Protobuf.Reflection.FieldOptions.Types.CType ctype_ = global::Google.Protobuf.Reflection.FieldOptions.Types.CType.STRING;
+    private global::Google.Protobuf.Reflection.FieldOptions.Types.CType ctype_ = 0;
     /// <summary>
     ///  The ctype option instructs the C++ code generator to use a different
     ///  representation of the field than it normally would.  See the specific
@@ -3469,7 +3436,7 @@ namespace Google.Protobuf.Reflection {
 
     /// <summary>Field number for the "jstype" field.</summary>
     public const int JstypeFieldNumber = 6;
-    private global::Google.Protobuf.Reflection.FieldOptions.Types.JSType jstype_ = global::Google.Protobuf.Reflection.FieldOptions.Types.JSType.JS_NORMAL;
+    private global::Google.Protobuf.Reflection.FieldOptions.Types.JSType jstype_ = 0;
     /// <summary>
     ///  The jstype option determines the JavaScript type used for values of the
     ///  field.  The option is permitted only for 64 bit integral and fixed types
@@ -3591,9 +3558,9 @@ namespace Google.Protobuf.Reflection {
 
     public override int GetHashCode() {
       int hash = 1;
-      if (Ctype != global::Google.Protobuf.Reflection.FieldOptions.Types.CType.STRING) hash ^= Ctype.GetHashCode();
+      if (Ctype != 0) hash ^= Ctype.GetHashCode();
       if (Packed != false) hash ^= Packed.GetHashCode();
-      if (Jstype != global::Google.Protobuf.Reflection.FieldOptions.Types.JSType.JS_NORMAL) hash ^= Jstype.GetHashCode();
+      if (Jstype != 0) hash ^= Jstype.GetHashCode();
       if (Lazy != false) hash ^= Lazy.GetHashCode();
       if (Deprecated != false) hash ^= Deprecated.GetHashCode();
       if (Weak != false) hash ^= Weak.GetHashCode();
@@ -3606,7 +3573,7 @@ namespace Google.Protobuf.Reflection {
     }
 
     public void WriteTo(pb::CodedOutputStream output) {
-      if (Ctype != global::Google.Protobuf.Reflection.FieldOptions.Types.CType.STRING) {
+      if (Ctype != 0) {
         output.WriteRawTag(8);
         output.WriteEnum((int) Ctype);
       }
@@ -3622,7 +3589,7 @@ namespace Google.Protobuf.Reflection {
         output.WriteRawTag(40);
         output.WriteBool(Lazy);
       }
-      if (Jstype != global::Google.Protobuf.Reflection.FieldOptions.Types.JSType.JS_NORMAL) {
+      if (Jstype != 0) {
         output.WriteRawTag(48);
         output.WriteEnum((int) Jstype);
       }
@@ -3635,13 +3602,13 @@ namespace Google.Protobuf.Reflection {
 
     public int CalculateSize() {
       int size = 0;
-      if (Ctype != global::Google.Protobuf.Reflection.FieldOptions.Types.CType.STRING) {
+      if (Ctype != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Ctype);
       }
       if (Packed != false) {
         size += 1 + 1;
       }
-      if (Jstype != global::Google.Protobuf.Reflection.FieldOptions.Types.JSType.JS_NORMAL) {
+      if (Jstype != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Jstype);
       }
       if (Lazy != false) {
@@ -3661,13 +3628,13 @@ namespace Google.Protobuf.Reflection {
       if (other == null) {
         return;
       }
-      if (other.Ctype != global::Google.Protobuf.Reflection.FieldOptions.Types.CType.STRING) {
+      if (other.Ctype != 0) {
         Ctype = other.Ctype;
       }
       if (other.Packed != false) {
         Packed = other.Packed;
       }
-      if (other.Jstype != global::Google.Protobuf.Reflection.FieldOptions.Types.JSType.JS_NORMAL) {
+      if (other.Jstype != 0) {
         Jstype = other.Jstype;
       }
       if (other.Lazy != false) {
@@ -3729,24 +3696,24 @@ namespace Google.Protobuf.Reflection {
         /// <summary>
         ///  Default mode.
         /// </summary>
-        STRING = 0,
-        CORD = 1,
-        STRING_PIECE = 2,
+        [pbr::OriginalName("STRING")] String = 0,
+        [pbr::OriginalName("CORD")] Cord = 1,
+        [pbr::OriginalName("STRING_PIECE")] StringPiece = 2,
       }
 
       internal enum JSType {
         /// <summary>
         ///  Use the default type.
         /// </summary>
-        JS_NORMAL = 0,
+        [pbr::OriginalName("JS_NORMAL")] JsNormal = 0,
         /// <summary>
         ///  Use JavaScript strings.
         /// </summary>
-        JS_STRING = 1,
+        [pbr::OriginalName("JS_STRING")] JsString = 1,
         /// <summary>
         ///  Use JavaScript numbers.
         /// </summary>
-        JS_NUMBER = 2,
+        [pbr::OriginalName("JS_NUMBER")] JsNumber = 2,
       }
 
     }
diff --git a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
index de6e5717..6c6f6ee0 100644
--- a/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
+++ b/csharp/src/Google.Protobuf/Reflection/FieldDescriptor.cs
@@ -133,41 +133,41 @@ namespace Google.Protobuf.Reflection
         {
             switch (type)
             {
-                case FieldDescriptorProto.Types.Type.TYPE_DOUBLE:
+                case FieldDescriptorProto.Types.Type.Double:
                     return FieldType.Double;
-                case FieldDescriptorProto.Types.Type.TYPE_FLOAT:
+                case FieldDescriptorProto.Types.Type.Float:
                     return FieldType.Float;
-                case FieldDescriptorProto.Types.Type.TYPE_INT64:
+                case FieldDescriptorProto.Types.Type.Int64:
                     return FieldType.Int64;
-                case FieldDescriptorProto.Types.Type.TYPE_UINT64:
+                case FieldDescriptorProto.Types.Type.Uint64:
                     return FieldType.UInt64;
-                case FieldDescriptorProto.Types.Type.TYPE_INT32:
+                case FieldDescriptorProto.Types.Type.Int32:
                     return FieldType.Int32;
-                case FieldDescriptorProto.Types.Type.TYPE_FIXED64:
+                case FieldDescriptorProto.Types.Type.Fixed64:
                     return FieldType.Fixed64;
-                case FieldDescriptorProto.Types.Type.TYPE_FIXED32:
+                case FieldDescriptorProto.Types.Type.Fixed32:
                     return FieldType.Fixed32;
-                case FieldDescriptorProto.Types.Type.TYPE_BOOL:
+                case FieldDescriptorProto.Types.Type.Bool:
                     return FieldType.Bool;
-                case FieldDescriptorProto.Types.Type.TYPE_STRING:
+                case FieldDescriptorProto.Types.Type.String:
                     return FieldType.String;
-                case FieldDescriptorProto.Types.Type.TYPE_GROUP:
+                case FieldDescriptorProto.Types.Type.Group:
                     return FieldType.Group;
-                case FieldDescriptorProto.Types.Type.TYPE_MESSAGE:
+                case FieldDescriptorProto.Types.Type.Message:
                     return FieldType.Message;
-                case FieldDescriptorProto.Types.Type.TYPE_BYTES:
+                case FieldDescriptorProto.Types.Type.Bytes:
                     return FieldType.Bytes;
-                case FieldDescriptorProto.Types.Type.TYPE_UINT32:
+                case FieldDescriptorProto.Types.Type.Uint32:
                     return FieldType.UInt32;
-                case FieldDescriptorProto.Types.Type.TYPE_ENUM:
+                case FieldDescriptorProto.Types.Type.Enum:
                     return FieldType.Enum;
-                case FieldDescriptorProto.Types.Type.TYPE_SFIXED32:
+                case FieldDescriptorProto.Types.Type.Sfixed32:
                     return FieldType.SFixed32;
-                case FieldDescriptorProto.Types.Type.TYPE_SFIXED64:
+                case FieldDescriptorProto.Types.Type.Sfixed64:
                     return FieldType.SFixed64;
-                case FieldDescriptorProto.Types.Type.TYPE_SINT32:
+                case FieldDescriptorProto.Types.Type.Sint32:
                     return FieldType.SInt32;
-                case FieldDescriptorProto.Types.Type.TYPE_SINT64:
+                case FieldDescriptorProto.Types.Type.Sint64:
                     return FieldType.SInt64;
                 default:
                     throw new ArgumentException("Invalid type specified");
@@ -177,7 +177,7 @@ namespace Google.Protobuf.Reflection
         /// <summary>
         /// Returns <c>true</c> if this field is a repeated field; <c>false</c> otherwise.
         /// </summary>
-        public bool IsRepeated => Proto.Label == FieldDescriptorProto.Types.Label.LABEL_REPEATED;
+        public bool IsRepeated => Proto.Label == FieldDescriptorProto.Types.Label.Repeated;
 
         /// <summary>
         /// Returns <c>true</c> if this field is a map field; <c>false</c> otherwise.
diff --git a/csharp/src/Google.Protobuf/Reflection/OriginalNameAttribute.cs b/csharp/src/Google.Protobuf/Reflection/OriginalNameAttribute.cs
new file mode 100644
index 00000000..27f9ab98
--- /dev/null
+++ b/csharp/src/Google.Protobuf/Reflection/OriginalNameAttribute.cs
@@ -0,0 +1,58 @@
+#region Copyright notice and license
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+
+using System;
+
+namespace Google.Protobuf.Reflection
+{
+    /// <summary>
+    /// Specifies the original name (in the .proto file) of a named element,
+    /// such as an enum value.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Field)]
+    public class OriginalNameAttribute : Attribute
+    {
+        /// <summary>
+        /// The name of the element in the .proto file.
+        /// </summary>
+        public string Name { get; set; }
+
+        /// <summary>
+        /// Constructs a new attribute instance for the given name.
+        /// </summary>
+        /// <param name="name">The name of the element in the .proto file.</param>
+        public OriginalNameAttribute(string name)
+        {
+            Name = ProtoPreconditions.CheckNotNull(name, nameof(name));
+        }
+    }
+}
+\ No newline at end of file
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
index 48cd99a1..871a383f 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Any.cs
@@ -24,9 +24,10 @@ namespace Google.Protobuf.WellKnownTypes {
       byte[] descriptorData = global::System.Convert.FromBase64String(
           string.Concat(
             "Chlnb29nbGUvcHJvdG9idWYvYW55LnByb3RvEg9nb29nbGUucHJvdG9idWYi",
-            "JgoDQW55EhAKCHR5cGVfdXJsGAEgASgJEg0KBXZhbHVlGAIgASgMQksKE2Nv",
-            "bS5nb29nbGUucHJvdG9idWZCCEFueVByb3RvUAGgAQGiAgNHUEKqAh5Hb29n",
-            "bGUuUHJvdG9idWYuV2VsbEtub3duVHlwZXNiBnByb3RvMw=="));
+            "JgoDQW55EhAKCHR5cGVfdXJsGAEgASgJEg0KBXZhbHVlGAIgASgMQnIKE2Nv",
+            "bS5nb29nbGUucHJvdG9idWZCCEFueVByb3RvUAFaJWdpdGh1Yi5jb20vZ29s",
+            "YW5nL3Byb3RvYnVmL3B0eXBlcy9hbnmgAQGiAgNHUEKqAh5Hb29nbGUuUHJv",
+            "dG9idWYuV2VsbEtub3duVHlwZXNiBnByb3RvMw=="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
@@ -38,8 +39,36 @@ namespace Google.Protobuf.WellKnownTypes {
   }
   #region Messages
   /// <summary>
-  ///  `Any` contains an arbitrary serialized message along with a URL
-  ///  that describes the type of the serialized message.
+  ///  `Any` contains an arbitrary serialized protocol buffer message along with a
+  ///  URL that describes the type of the serialized message.
+  ///
+  ///  Protobuf library provides support to pack/unpack Any values in the form
+  ///  of utility functions or additional generated methods of the Any type.
+  ///
+  ///  Example 1: Pack and unpack a message in C++.
+  ///
+  ///      Foo foo = ...;
+  ///      Any any;
+  ///      any.PackFrom(foo);
+  ///      ...
+  ///      if (any.UnpackTo(&amp;foo)) {
+  ///        ...
+  ///      }
+  ///
+  ///  Example 2: Pack and unpack a message in Java.
+  ///
+  ///      Foo foo = ...;
+  ///      Any any = Any.pack(foo);
+  ///      ...
+  ///      if (any.is(Foo.class)) {
+  ///        foo = any.unpack(Foo.class);
+  ///      }
+  ///
+  ///  The pack methods provided by protobuf library will by default use
+  ///  'type.googleapis.com/full.type.name' as the type URL and the unpack
+  ///  methods only use the fully qualified type name after the last '/'
+  ///  in the type URL, for example "foo.bar.com/x/y.z" will yield type
+  ///  name "y.z".
   ///
   ///  JSON
   ///  ====
@@ -102,7 +131,7 @@ namespace Google.Protobuf.WellKnownTypes {
     private string typeUrl_ = "";
     /// <summary>
     ///  A URL/resource name whose content describes the type of the
-    ///  serialized message.
+    ///  serialized protocol buffer message.
     ///
     ///  For URLs which use the schema `http`, `https`, or no schema, the
     ///  following restrictions and interpretations apply:
@@ -110,6 +139,8 @@ namespace Google.Protobuf.WellKnownTypes {
     ///  * If no schema is provided, `https` is assumed.
     ///  * The last segment of the URL's path must represent the fully
     ///    qualified name of the type (as in `path/google.protobuf.Duration`).
+    ///    The name should be in a canonical form (e.g., leading "." is
+    ///    not accepted).
     ///  * An HTTP GET on the URL must yield a [google.protobuf.Type][]
     ///    value in binary format, or produce an error.
     ///  * Applications are allowed to cache lookup results based on the
@@ -132,7 +163,7 @@ namespace Google.Protobuf.WellKnownTypes {
     public const int ValueFieldNumber = 2;
     private pb::ByteString value_ = pb::ByteString.Empty;
     /// <summary>
-    ///  Must be valid serialized data of the above specified type.
+    ///  Must be a valid serialized protocol buffer of the above specified type.
     /// </summary>
     public pb::ByteString Value {
       get { return value_; }
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
index de7aea3a..e568a2c9 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Api.cs
@@ -185,7 +185,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "syntax" field.</summary>
     public const int SyntaxFieldNumber = 7;
-    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2;
+    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = 0;
     /// <summary>
     ///  The source syntax of the service.
     /// </summary>
@@ -225,7 +225,7 @@ namespace Google.Protobuf.WellKnownTypes {
       if (Version.Length != 0) hash ^= Version.GetHashCode();
       if (sourceContext_ != null) hash ^= SourceContext.GetHashCode();
       hash ^= mixins_.GetHashCode();
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) hash ^= Syntax.GetHashCode();
+      if (Syntax != 0) hash ^= Syntax.GetHashCode();
       return hash;
     }
 
@@ -249,7 +249,7 @@ namespace Google.Protobuf.WellKnownTypes {
         output.WriteMessage(SourceContext);
       }
       mixins_.WriteTo(output, _repeated_mixins_codec);
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         output.WriteRawTag(56);
         output.WriteEnum((int) Syntax);
       }
@@ -269,7 +269,7 @@ namespace Google.Protobuf.WellKnownTypes {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(SourceContext);
       }
       size += mixins_.CalculateSize(_repeated_mixins_codec);
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Syntax);
       }
       return size;
@@ -294,7 +294,7 @@ namespace Google.Protobuf.WellKnownTypes {
         SourceContext.MergeFrom(other.SourceContext);
       }
       mixins_.Add(other.mixins_);
-      if (other.Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (other.Syntax != 0) {
         Syntax = other.Syntax;
       }
     }
@@ -458,7 +458,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "syntax" field.</summary>
     public const int SyntaxFieldNumber = 7;
-    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2;
+    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = 0;
     /// <summary>
     ///  The source syntax of this method.
     /// </summary>
@@ -498,7 +498,7 @@ namespace Google.Protobuf.WellKnownTypes {
       if (ResponseTypeUrl.Length != 0) hash ^= ResponseTypeUrl.GetHashCode();
       if (ResponseStreaming != false) hash ^= ResponseStreaming.GetHashCode();
       hash ^= options_.GetHashCode();
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) hash ^= Syntax.GetHashCode();
+      if (Syntax != 0) hash ^= Syntax.GetHashCode();
       return hash;
     }
 
@@ -528,7 +528,7 @@ namespace Google.Protobuf.WellKnownTypes {
         output.WriteBool(ResponseStreaming);
       }
       options_.WriteTo(output, _repeated_options_codec);
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         output.WriteRawTag(56);
         output.WriteEnum((int) Syntax);
       }
@@ -552,7 +552,7 @@ namespace Google.Protobuf.WellKnownTypes {
         size += 1 + 1;
       }
       size += options_.CalculateSize(_repeated_options_codec);
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Syntax);
       }
       return size;
@@ -578,7 +578,7 @@ namespace Google.Protobuf.WellKnownTypes {
         ResponseStreaming = other.ResponseStreaming;
       }
       options_.Add(other.options_);
-      if (other.Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (other.Syntax != 0) {
         Syntax = other.Syntax;
       }
     }
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
index 73e221d4..f17358f4 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Duration.cs
@@ -25,9 +25,10 @@ namespace Google.Protobuf.WellKnownTypes {
           string.Concat(
             "Ch5nb29nbGUvcHJvdG9idWYvZHVyYXRpb24ucHJvdG8SD2dvb2dsZS5wcm90",
             "b2J1ZiIqCghEdXJhdGlvbhIPCgdzZWNvbmRzGAEgASgDEg0KBW5hbm9zGAIg",
-            "ASgFQlAKE2NvbS5nb29nbGUucHJvdG9idWZCDUR1cmF0aW9uUHJvdG9QAaAB",
-            "AaICA0dQQqoCHkdvb2dsZS5Qcm90b2J1Zi5XZWxsS25vd25UeXBlc2IGcHJv",
-            "dG8z"));
+            "ASgFQnwKE2NvbS5nb29nbGUucHJvdG9idWZCDUR1cmF0aW9uUHJvdG9QAVoq",
+            "Z2l0aHViLmNvbS9nb2xhbmcvcHJvdG9idWYvcHR5cGVzL2R1cmF0aW9uoAEB",
+            "ogIDR1BCqgIeR29vZ2xlLlByb3RvYnVmLldlbGxLbm93blR5cGVzYgZwcm90",
+            "bzM="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
index 6cad4124..e08ea240 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Empty.cs
@@ -24,9 +24,10 @@ namespace Google.Protobuf.WellKnownTypes {
       byte[] descriptorData = global::System.Convert.FromBase64String(
           string.Concat(
             "Chtnb29nbGUvcHJvdG9idWYvZW1wdHkucHJvdG8SD2dvb2dsZS5wcm90b2J1",
-            "ZiIHCgVFbXB0eUJQChNjb20uZ29vZ2xlLnByb3RvYnVmQgpFbXB0eVByb3Rv",
-            "UAGgAQH4AQGiAgNHUEKqAh5Hb29nbGUuUHJvdG9idWYuV2VsbEtub3duVHlw",
-            "ZXNiBnByb3RvMw=="));
+            "ZiIHCgVFbXB0eUJ5ChNjb20uZ29vZ2xlLnByb3RvYnVmQgpFbXB0eVByb3Rv",
+            "UAFaJ2dpdGh1Yi5jb20vZ29sYW5nL3Byb3RvYnVmL3B0eXBlcy9lbXB0eaAB",
+            "AfgBAaICA0dQQqoCHkdvb2dsZS5Qcm90b2J1Zi5XZWxsS25vd25UeXBlc2IG",
+            "cHJvdG8z"));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs b/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
index 2ba2b96f..6f0a64d6 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/FieldMask.cs
@@ -86,7 +86,7 @@ namespace Google.Protobuf.WellKnownTypes {
   ///  operation applies to all fields (as if a FieldMask of all fields
   ///  had been specified).
   ///
-  ///  Note that a field mask does not necessarily applies to the
+  ///  Note that a field mask does not necessarily apply to the
   ///  top-level response message. In case of a REST get operation, the
   ///  field mask applies directly to the response, but in case of a REST
   ///  list operation, the mask instead applies to each individual message
@@ -159,6 +159,33 @@ namespace Google.Protobuf.WellKnownTypes {
   ///      {
   ///        mask: "user.displayName,photo"
   ///      }
+  ///
+  ///  # Field Masks and Oneof Fields
+  ///
+  ///  Field masks treat fields in oneofs just as regular fields. Consider the
+  ///  following message:
+  ///
+  ///      message SampleMessage {
+  ///        oneof test_oneof {
+  ///          string name = 4;
+  ///          SubMessage sub_message = 9;
+  ///        }
+  ///      }
+  ///
+  ///  The field mask can be:
+  ///
+  ///      mask {
+  ///        paths: "name"
+  ///      }
+  ///
+  ///  Or:
+  ///
+  ///      mask {
+  ///        paths: "sub_message"
+  ///      }
+  ///
+  ///  Note that oneof type names ("test_oneof" in this case) cannot be used in
+  ///  paths.
   /// </summary>
   [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
   public sealed partial class FieldMask : pb::IMessage<FieldMask> {
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
index 8e2ce8cf..edc8940d 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Struct.cs
@@ -34,9 +34,10 @@ namespace Google.Protobuf.WellKnownTypes {
             "ABIwCgpsaXN0X3ZhbHVlGAYgASgLMhouZ29vZ2xlLnByb3RvYnVmLkxpc3RW",
             "YWx1ZUgAQgYKBGtpbmQiMwoJTGlzdFZhbHVlEiYKBnZhbHVlcxgBIAMoCzIW",
             "Lmdvb2dsZS5wcm90b2J1Zi5WYWx1ZSobCglOdWxsVmFsdWUSDgoKTlVMTF9W",
-            "QUxVRRAAQk4KE2NvbS5nb29nbGUucHJvdG9idWZCC1N0cnVjdFByb3RvUAGg",
-            "AQGiAgNHUEKqAh5Hb29nbGUuUHJvdG9idWYuV2VsbEtub3duVHlwZXNiBnBy",
-            "b3RvMw=="));
+            "QUxVRRAAQoEBChNjb20uZ29vZ2xlLnByb3RvYnVmQgtTdHJ1Y3RQcm90b1AB",
+            "WjFnaXRodWIuY29tL2dvbGFuZy9wcm90b2J1Zi9wdHlwZXMvc3RydWN0O3N0",
+            "cnVjdHBioAEBogIDR1BCqgIeR29vZ2xlLlByb3RvYnVmLldlbGxLbm93blR5",
+            "cGVzYgZwcm90bzM="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(new[] {typeof(global::Google.Protobuf.WellKnownTypes.NullValue), }, new pbr::GeneratedClrTypeInfo[] {
@@ -59,7 +60,7 @@ namespace Google.Protobuf.WellKnownTypes {
     /// <summary>
     ///  Null value.
     /// </summary>
-    NULL_VALUE = 0,
+    [pbr::OriginalName("NULL_VALUE")] NullValue = 0,
   }
 
   #endregion
@@ -108,7 +109,7 @@ namespace Google.Protobuf.WellKnownTypes {
         = new pbc::MapField<string, global::Google.Protobuf.WellKnownTypes.Value>.Codec(pb::FieldCodec.ForString(10), pb::FieldCodec.ForMessage(18, global::Google.Protobuf.WellKnownTypes.Value.Parser), 10);
     private readonly pbc::MapField<string, global::Google.Protobuf.WellKnownTypes.Value> fields_ = new pbc::MapField<string, global::Google.Protobuf.WellKnownTypes.Value>();
     /// <summary>
-    ///  Map of dynamically typed values.
+    ///  Unordered map of dynamically typed values.
     /// </summary>
     public pbc::MapField<string, global::Google.Protobuf.WellKnownTypes.Value> Fields {
       get { return fields_; }
@@ -234,7 +235,7 @@ namespace Google.Protobuf.WellKnownTypes {
     ///  Represents a null value.
     /// </summary>
     public global::Google.Protobuf.WellKnownTypes.NullValue NullValue {
-      get { return kindCase_ == KindOneofCase.NullValue ? (global::Google.Protobuf.WellKnownTypes.NullValue) kind_ : global::Google.Protobuf.WellKnownTypes.NullValue.NULL_VALUE; }
+      get { return kindCase_ == KindOneofCase.NullValue ? (global::Google.Protobuf.WellKnownTypes.NullValue) kind_ : 0; }
       set {
         kind_ = value;
         kindCase_ = KindOneofCase.NullValue;
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
index 318b0f61..053b88bd 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Timestamp.cs
@@ -25,9 +25,10 @@ namespace Google.Protobuf.WellKnownTypes {
           string.Concat(
             "Ch9nb29nbGUvcHJvdG9idWYvdGltZXN0YW1wLnByb3RvEg9nb29nbGUucHJv",
             "dG9idWYiKwoJVGltZXN0YW1wEg8KB3NlY29uZHMYASABKAMSDQoFbmFub3MY",
-            "AiABKAVCVAoTY29tLmdvb2dsZS5wcm90b2J1ZkIOVGltZXN0YW1wUHJvdG9Q",
-            "AaABAfgBAaICA0dQQqoCHkdvb2dsZS5Qcm90b2J1Zi5XZWxsS25vd25UeXBl",
-            "c2IGcHJvdG8z"));
+            "AiABKAVCgQEKE2NvbS5nb29nbGUucHJvdG9idWZCDlRpbWVzdGFtcFByb3Rv",
+            "UAFaK2dpdGh1Yi5jb20vZ29sYW5nL3Byb3RvYnVmL3B0eXBlcy90aW1lc3Rh",
+            "bXCgAQH4AQGiAgNHUEKqAh5Hb29nbGUuUHJvdG9idWYuV2VsbEtub3duVHlw",
+            "ZXNiBnByb3RvMw=="));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
index 8faa1d1c..657c2464 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Type.cs
@@ -79,11 +79,11 @@ namespace Google.Protobuf.WellKnownTypes {
     /// <summary>
     ///  Syntax `proto2`.
     /// </summary>
-    SYNTAX_PROTO2 = 0,
+    [pbr::OriginalName("SYNTAX_PROTO2")] Proto2 = 0,
     /// <summary>
     ///  Syntax `proto3`.
     /// </summary>
-    SYNTAX_PROTO3 = 1,
+    [pbr::OriginalName("SYNTAX_PROTO3")] Proto3 = 1,
   }
 
   #endregion
@@ -188,7 +188,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "syntax" field.</summary>
     public const int SyntaxFieldNumber = 6;
-    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2;
+    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = 0;
     /// <summary>
     ///  The source syntax.
     /// </summary>
@@ -226,7 +226,7 @@ namespace Google.Protobuf.WellKnownTypes {
       hash ^= oneofs_.GetHashCode();
       hash ^= options_.GetHashCode();
       if (sourceContext_ != null) hash ^= SourceContext.GetHashCode();
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) hash ^= Syntax.GetHashCode();
+      if (Syntax != 0) hash ^= Syntax.GetHashCode();
       return hash;
     }
 
@@ -246,7 +246,7 @@ namespace Google.Protobuf.WellKnownTypes {
         output.WriteRawTag(42);
         output.WriteMessage(SourceContext);
       }
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         output.WriteRawTag(48);
         output.WriteEnum((int) Syntax);
       }
@@ -263,7 +263,7 @@ namespace Google.Protobuf.WellKnownTypes {
       if (sourceContext_ != null) {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(SourceContext);
       }
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Syntax);
       }
       return size;
@@ -285,7 +285,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
         SourceContext.MergeFrom(other.SourceContext);
       }
-      if (other.Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (other.Syntax != 0) {
         Syntax = other.Syntax;
       }
     }
@@ -371,7 +371,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "kind" field.</summary>
     public const int KindFieldNumber = 1;
-    private global::Google.Protobuf.WellKnownTypes.Field.Types.Kind kind_ = global::Google.Protobuf.WellKnownTypes.Field.Types.Kind.TYPE_UNKNOWN;
+    private global::Google.Protobuf.WellKnownTypes.Field.Types.Kind kind_ = 0;
     /// <summary>
     ///  The field type.
     /// </summary>
@@ -384,7 +384,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "cardinality" field.</summary>
     public const int CardinalityFieldNumber = 2;
-    private global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality cardinality_ = global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality.CARDINALITY_UNKNOWN;
+    private global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality cardinality_ = 0;
     /// <summary>
     ///  The field cardinality.
     /// </summary>
@@ -526,8 +526,8 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public override int GetHashCode() {
       int hash = 1;
-      if (Kind != global::Google.Protobuf.WellKnownTypes.Field.Types.Kind.TYPE_UNKNOWN) hash ^= Kind.GetHashCode();
-      if (Cardinality != global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality.CARDINALITY_UNKNOWN) hash ^= Cardinality.GetHashCode();
+      if (Kind != 0) hash ^= Kind.GetHashCode();
+      if (Cardinality != 0) hash ^= Cardinality.GetHashCode();
       if (Number != 0) hash ^= Number.GetHashCode();
       if (Name.Length != 0) hash ^= Name.GetHashCode();
       if (TypeUrl.Length != 0) hash ^= TypeUrl.GetHashCode();
@@ -544,11 +544,11 @@ namespace Google.Protobuf.WellKnownTypes {
     }
 
     public void WriteTo(pb::CodedOutputStream output) {
-      if (Kind != global::Google.Protobuf.WellKnownTypes.Field.Types.Kind.TYPE_UNKNOWN) {
+      if (Kind != 0) {
         output.WriteRawTag(8);
         output.WriteEnum((int) Kind);
       }
-      if (Cardinality != global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality.CARDINALITY_UNKNOWN) {
+      if (Cardinality != 0) {
         output.WriteRawTag(16);
         output.WriteEnum((int) Cardinality);
       }
@@ -585,10 +585,10 @@ namespace Google.Protobuf.WellKnownTypes {
 
     public int CalculateSize() {
       int size = 0;
-      if (Kind != global::Google.Protobuf.WellKnownTypes.Field.Types.Kind.TYPE_UNKNOWN) {
+      if (Kind != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Kind);
       }
-      if (Cardinality != global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality.CARDINALITY_UNKNOWN) {
+      if (Cardinality != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Cardinality);
       }
       if (Number != 0) {
@@ -620,10 +620,10 @@ namespace Google.Protobuf.WellKnownTypes {
       if (other == null) {
         return;
       }
-      if (other.Kind != global::Google.Protobuf.WellKnownTypes.Field.Types.Kind.TYPE_UNKNOWN) {
+      if (other.Kind != 0) {
         Kind = other.Kind;
       }
-      if (other.Cardinality != global::Google.Protobuf.WellKnownTypes.Field.Types.Cardinality.CARDINALITY_UNKNOWN) {
+      if (other.Cardinality != 0) {
         Cardinality = other.Cardinality;
       }
       if (other.Number != 0) {
@@ -712,79 +712,79 @@ namespace Google.Protobuf.WellKnownTypes {
         /// <summary>
         ///  Field type unknown.
         /// </summary>
-        TYPE_UNKNOWN = 0,
+        [pbr::OriginalName("TYPE_UNKNOWN")] TypeUnknown = 0,
         /// <summary>
         ///  Field type double.
         /// </summary>
-        TYPE_DOUBLE = 1,
+        [pbr::OriginalName("TYPE_DOUBLE")] TypeDouble = 1,
         /// <summary>
         ///  Field type float.
         /// </summary>
-        TYPE_FLOAT = 2,
+        [pbr::OriginalName("TYPE_FLOAT")] TypeFloat = 2,
         /// <summary>
         ///  Field type int64.
         /// </summary>
-        TYPE_INT64 = 3,
+        [pbr::OriginalName("TYPE_INT64")] TypeInt64 = 3,
         /// <summary>
         ///  Field type uint64.
         /// </summary>
-        TYPE_UINT64 = 4,
+        [pbr::OriginalName("TYPE_UINT64")] TypeUint64 = 4,
         /// <summary>
         ///  Field type int32.
         /// </summary>
-        TYPE_INT32 = 5,
+        [pbr::OriginalName("TYPE_INT32")] TypeInt32 = 5,
         /// <summary>
         ///  Field type fixed64.
         /// </summary>
-        TYPE_FIXED64 = 6,
+        [pbr::OriginalName("TYPE_FIXED64")] TypeFixed64 = 6,
         /// <summary>
         ///  Field type fixed32.
         /// </summary>
-        TYPE_FIXED32 = 7,
+        [pbr::OriginalName("TYPE_FIXED32")] TypeFixed32 = 7,
         /// <summary>
         ///  Field type bool.
         /// </summary>
-        TYPE_BOOL = 8,
+        [pbr::OriginalName("TYPE_BOOL")] TypeBool = 8,
         /// <summary>
         ///  Field type string.
         /// </summary>
-        TYPE_STRING = 9,
+        [pbr::OriginalName("TYPE_STRING")] TypeString = 9,
         /// <summary>
         ///  Field type group. Proto2 syntax only, and deprecated.
         /// </summary>
-        TYPE_GROUP = 10,
+        [pbr::OriginalName("TYPE_GROUP")] TypeGroup = 10,
         /// <summary>
         ///  Field type message.
         /// </summary>
-        TYPE_MESSAGE = 11,
+        [pbr::OriginalName("TYPE_MESSAGE")] TypeMessage = 11,
         /// <summary>
         ///  Field type bytes.
         /// </summary>
-        TYPE_BYTES = 12,
+        [pbr::OriginalName("TYPE_BYTES")] TypeBytes = 12,
         /// <summary>
         ///  Field type uint32.
         /// </summary>
-        TYPE_UINT32 = 13,
+        [pbr::OriginalName("TYPE_UINT32")] TypeUint32 = 13,
         /// <summary>
         ///  Field type enum.
         /// </summary>
-        TYPE_ENUM = 14,
+        [pbr::OriginalName("TYPE_ENUM")] TypeEnum = 14,
         /// <summary>
         ///  Field type sfixed32.
         /// </summary>
-        TYPE_SFIXED32 = 15,
+        [pbr::OriginalName("TYPE_SFIXED32")] TypeSfixed32 = 15,
         /// <summary>
         ///  Field type sfixed64.
         /// </summary>
-        TYPE_SFIXED64 = 16,
+        [pbr::OriginalName("TYPE_SFIXED64")] TypeSfixed64 = 16,
         /// <summary>
         ///  Field type sint32.
         /// </summary>
-        TYPE_SINT32 = 17,
+        [pbr::OriginalName("TYPE_SINT32")] TypeSint32 = 17,
         /// <summary>
         ///  Field type sint64.
         /// </summary>
-        TYPE_SINT64 = 18,
+        [pbr::OriginalName("TYPE_SINT64")] TypeSint64 = 18,
       }
 
       /// <summary>
@@ -794,19 +794,19 @@ namespace Google.Protobuf.WellKnownTypes {
         /// <summary>
         ///  For fields with unknown cardinality.
         /// </summary>
-        CARDINALITY_UNKNOWN = 0,
+        [pbr::OriginalName("CARDINALITY_UNKNOWN")] Unknown = 0,
         /// <summary>
         ///  For optional fields.
         /// </summary>
-        CARDINALITY_OPTIONAL = 1,
+        [pbr::OriginalName("CARDINALITY_OPTIONAL")] Optional = 1,
         /// <summary>
         ///  For required fields. Proto2 syntax only.
         /// </summary>
-        CARDINALITY_REQUIRED = 2,
+        [pbr::OriginalName("CARDINALITY_REQUIRED")] Required = 2,
         /// <summary>
         ///  For repeated fields.
         /// </summary>
-        CARDINALITY_REPEATED = 3,
+        [pbr::OriginalName("CARDINALITY_REPEATED")] Repeated = 3,
       }
 
     }
@@ -900,7 +900,7 @@ namespace Google.Protobuf.WellKnownTypes {
 
     /// <summary>Field number for the "syntax" field.</summary>
     public const int SyntaxFieldNumber = 5;
-    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2;
+    private global::Google.Protobuf.WellKnownTypes.Syntax syntax_ = 0;
     /// <summary>
     ///  The source syntax.
     /// </summary>
@@ -936,7 +936,7 @@ namespace Google.Protobuf.WellKnownTypes {
       hash ^= enumvalue_.GetHashCode();
       hash ^= options_.GetHashCode();
       if (sourceContext_ != null) hash ^= SourceContext.GetHashCode();
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) hash ^= Syntax.GetHashCode();
+      if (Syntax != 0) hash ^= Syntax.GetHashCode();
       return hash;
     }
 
@@ -955,7 +955,7 @@ namespace Google.Protobuf.WellKnownTypes {
         output.WriteRawTag(34);
         output.WriteMessage(SourceContext);
       }
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         output.WriteRawTag(40);
         output.WriteEnum((int) Syntax);
       }
@@ -971,7 +971,7 @@ namespace Google.Protobuf.WellKnownTypes {
       if (sourceContext_ != null) {
         size += 1 + pb::CodedOutputStream.ComputeMessageSize(SourceContext);
       }
-      if (Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (Syntax != 0) {
         size += 1 + pb::CodedOutputStream.ComputeEnumSize((int) Syntax);
       }
       return size;
@@ -992,7 +992,7 @@ namespace Google.Protobuf.WellKnownTypes {
         }
         SourceContext.MergeFrom(other.SourceContext);
       }
-      if (other.Syntax != global::Google.Protobuf.WellKnownTypes.Syntax.SYNTAX_PROTO2) {
+      if (other.Syntax != 0) {
         Syntax = other.Syntax;
       }
     }
diff --git a/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs b/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
index d6796d1a..c8867d0e 100644
--- a/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
+++ b/csharp/src/Google.Protobuf/WellKnownTypes/Wrappers.cs
@@ -29,10 +29,10 @@ namespace Google.Protobuf.WellKnownTypes {
             "KAMiHAoLVUludDY0VmFsdWUSDQoFdmFsdWUYASABKAQiGwoKSW50MzJWYWx1",
             "ZRINCgV2YWx1ZRgBIAEoBSIcCgtVSW50MzJWYWx1ZRINCgV2YWx1ZRgBIAEo",
             "DSIaCglCb29sVmFsdWUSDQoFdmFsdWUYASABKAgiHAoLU3RyaW5nVmFsdWUS",
-            "DQoFdmFsdWUYASABKAkiGwoKQnl0ZXNWYWx1ZRINCgV2YWx1ZRgBIAEoDEJT",
-            "ChNjb20uZ29vZ2xlLnByb3RvYnVmQg1XcmFwcGVyc1Byb3RvUAGgAQH4AQGi",
-            "AgNHUEKqAh5Hb29nbGUuUHJvdG9idWYuV2VsbEtub3duVHlwZXNiBnByb3Rv",
-            "Mw=="));
+            "DQoFdmFsdWUYASABKAkiGwoKQnl0ZXNWYWx1ZRINCgV2YWx1ZRgBIAEoDEJ/",
+            "ChNjb20uZ29vZ2xlLnByb3RvYnVmQg1XcmFwcGVyc1Byb3RvUAFaKmdpdGh1",
+            "Yi5jb20vZ29sYW5nL3Byb3RvYnVmL3B0eXBlcy93cmFwcGVyc6ABAfgBAaIC",
+            "A0dQQqoCHkdvb2dsZS5Qcm90b2J1Zi5XZWxsS25vd25UeXBlc2IGcHJvdG8z"));
       descriptor = pbr::FileDescriptor.FromGeneratedCode(descriptorData,
           new pbr::FileDescriptor[] { },
           new pbr::GeneratedClrTypeInfo(null, new pbr::GeneratedClrTypeInfo[] {
diff --git a/docs/swift/DesignDoc.md b/docs/swift/DesignDoc.md
new file mode 100644
index 00000000..364a4d3f
--- /dev/null
+++ b/docs/swift/DesignDoc.md
@@ -0,0 +1,674 @@
+# Protocol Buffers in Swift
+
+## Objective
+
+This document describes the user-facing API and internal implementation of
+proto2 and proto3 messages in Apple’s Swift programming language.
+
+One of the key goals of protobufs is to provide idiomatic APIs for each
+language. In that vein, **interoperability with Objective-C is a non-goal of
+this proposal.** Protobuf users who need to pass messages between Objective-C
+and Swift code in the same application should use the existing Objective-C proto
+library. The goal of the effort described here is to provide an API for protobuf
+messages that uses features specific to Swift—optional types, algebraic
+enumerated types, value types, and so forth—in a natural way that will delight,
+rather than surprise, users of the language.
+
+## Naming
+
+*   By convention, both typical protobuf message names and Swift structs/classes
+    are `UpperCamelCase`, so for most messages, the name of a message can be the
+    same as the name of its generated type. (However, see the discussion below
+    about prefixes under [Packages](#packages).)
+
+*   Enum cases in protobufs typically are `UPPERCASE_WITH_UNDERSCORES`, whereas
+    in Swift they are `lowerCamelCase` (as of the Swift 3 API design
+    guidelines). We will transform the names to match Swift convention, using
+    a whitelist similar to the Objective-C compiler plugin to handle commonly
+    used acronyms.
+
+*   Typical fields in proto messages are `lowercase_with_underscores`, while in
+    Swift they are `lowerCamelCase`. We will transform the names to match
+    Swift convention by removing the underscores and uppercasing the subsequent
+    letter.
+
+## Swift reserved words
+
+Swift has a large set of reserved words—some always reserved and some
+contextually reserved (that is, they can be used as identifiers in contexts
+where they would not be confused). As of Swift 2.2, the set of always-reserved
+words is:
+
+```
+_, #available, #column, #else, #elseif, #endif, #file, #function, #if, #line,
+#selector, as, associatedtype, break, case, catch, class, continue, default,
+defer, deinit, do, dynamicType, else, enum, extension, fallthrough, false, for,
+func, guard, if, import, in, init, inout, internal, is, let, nil, operator,
+private, protocol, public, repeat, rethrows, return, self, Self, static,
+struct, subscript, super, switch, throw, throws, true, try, typealias, var,
+where, while
+```
+
+The set of contextually reserved words is:
+
+```
+associativity, convenience, dynamic, didSet, final, get, infix, indirect,
+lazy, left, mutating, none, nonmutating, optional, override, postfix,
+precedence, prefix, Protocol, required, right, set, Type, unowned, weak,
+willSet
+```
+
+It is possible to use any reserved word as an identifier by escaping it with
+backticks (for example, ``let `class` = 5``). Other name-mangling schemes would
+require us to transform the names themselves (for example, by appending an
+underscore), which requires us to then ensure that the new name does not collide
+with something else in the same namespace.
+
+While the backtick feature may not be widely known by all Swift developers, a
+small amount of user education can address this and it seems like the best
+approach. We can unconditionally surround all property names with backticks to
+simplify generation.
+
+Some remapping will still be required, though, to avoid collisions between
+generated properties and the names of methods and properties defined in the base
+protocol/implementation of messages.
+
+# Features of Protocol Buffers
+
+This section describes how the features of the protocol buffer syntaxes (proto2
+and proto3) map to features in Swift—what the code generated from a proto will
+look like, and how it will be implemented in the underlying library.
+
+## Packages
+
+Modules are the main form of namespacing in Swift, but they are not declared
+using syntactic constructs like namespaces in C++ or packages in Java. Instead,
+they are tied to build targets in Xcode (or, in the future with open-source
+Swift, declarations in a Swift Package Manager manifest). They also do not
+easily support nesting submodules (Clang module maps support this, but pure
+Swift does not yet provide a way to define submodules).
+
+We will generate types with fully-qualified underscore-delimited names. For
+example, a message `Baz` in package `foo.bar` would generate a struct named
+`Foo_Bar_Baz`. For each fully-qualified proto message, there will be exactly one
+unique type symbol emitted in the generated binary.
+
+Users are likely to balk at the ugliness of underscore-delimited names for every
+generated type. To improve upon this situation, we will add a new string file
+level option, `swift_package_typealias`, that can be added to `.proto` files.
+When present, this will cause `typealias`es to be added to the generated Swift
+messages that replace the package name prefix with the provided string. For
+example, the following `.proto` file:
+
+```protobuf
+option swift_package_typealias = "FBP";
+package foo.bar;
+
+message Baz {
+  // Message fields
+}
+```
+
+would generate the following Swift source:
+
+```swift
+public struct Foo_Bar_Baz {
+  // Message fields and other methods
+}
+
+typealias FBPBaz = Foo_Bar_Baz
+```
+
+It should be noted that this type alias is recorded in the generated
+`.swiftmodule` so that code importing the module can refer to it, but it does
+not cause a new symbol to be generated in the compiled binary (i.e., we do not
+risk compiled size bloat by adding `typealias`es for every type).
+
+Other strategies to handle packages that were considered and rejected can be
+found in [Appendix A](#appendix-a-rejected-strategies-to-handle-packages).
+
+## Messages
+
+Proto messages are natural value types and we will generate messages as structs
+instead of classes. Users will benefit from Swift’s built-in behavior with
+regard to mutability. We will define a `ProtoMessage` protocol that defines the
+common methods and properties for all messages (such as serialization) and also
+lets users treat messages polymorphically. Any shared method implementations
+that do not differ between individual messages can be implemented in a protocol
+extension.
+
+The backing storage itself for fields of a message will be managed by a
+`ProtoFieldStorage` type that uses an internal dictionary keyed by field number,
+and whose values are the value of the field with that number (up-cast to Swift’s
+`Any` type). This class will provide type-safe getters and setters so that
+generated messages can manipulate this storage, and core serialization logic
+will live here as well. Furthermore, factoring the storage out into a separate
+type, rather than inlining the fields as stored properties in the message
+itself, lets us implement copy-on-write efficiently to support passing around
+large messages. (Furthermore, because the messages themselves are value types,
+inlining fields is not possible if the fields are submessages of the same type,
+or a type that eventually includes a submessage of the same type.)
+
+### Required fields (proto2 only)
+
+Required fields in proto2 messages seem like they could be naturally represented
+by non-optional properties in Swift, but this presents some problems/concerns.
+
+Serialization APIs permit partial serialization, which allows required fields to
+remain unset. Furthermore, other language APIs still provide `has*` and `clear*`
+methods for required fields, and knowing whether a property has a value when the
+message is in memory is still useful.
+
+For example, an e-mail draft message may have the “to” address required on the
+wire, but when the user constructs it in memory, it doesn’t make sense to force
+a value until they provide one. We only want to force a value to be present when
+the message is serialized to the wire. Using non-optional properties prevents
+this use case, and makes client usage awkward because the user would be forced
+to select a sentinel or placeholder value for any required fields at the time
+the message was created.
+
+### Default values
+
+In proto2, fields can have a default value specified that may be a value other
+than the default value for its corresponding language type (for example, a
+default value of 5 instead of 0 for an integer). When reading a field that is
+not explicitly set, the user expects to get that value. This makes Swift
+optionals (i.e., `Foo?`) unsuitable for fields in general. Unfortunately, we
+cannot implement our own “enhanced optional” type without severely complicating
+usage (Swift’s use of type inference and its lack of implicit conversions would
+require manual unwrapping of every property value).
+
+Instead, we can use **implicitly unwrapped optionals.** For example, a property
+generated for a field of type `int32` would have Swift type `Int32!`. These
+properties would behave with the following characteristics, which mirror the
+nil-resettable properties used elsewhere in Apple’s SDKs (for example,
+`UIView.tintColor`):
+
+*   Assigning a non-nil value to a property sets the field to that value.
+*   Assigning nil to a property clears the field (its internal representation is
+    nilled out).
+*   Reading the value of a property returns its value if it is set, or returns
+    its default value if it is not set. Reading a property never returns nil.
+
+The final point in the list above implies that the optional cannot be checked to
+determine if the field is set to a value other than its default: it will never
+be nil. Instead, we must provide `has*` methods for each field to allow the user
+to check this. These methods will be public in proto2. In proto3, these methods
+will be private (if generated at all), since the user can test the returned
+value against the zero value for that type.
+
+### Autocreation of nested messages
+
+For convenience, dotting into an unset field representing a nested message will
+return an instance of that message with default values. As in the Objective-C
+implementation, this does not actually cause the field to be set until the
+returned message is mutated. Fortunately, thanks to the way mutability of value
+types is implemented in Swift, the language automatically handles the
+reassignment-on-mutation for us. A static singleton instance containing default
+values can be associated with each message that can be returned when reading, so
+copies are only made by the Swift runtime when mutation occurs. For example,
+given the following proto:
+
+```protobuf
+message Node {
+  Node child = 1;
+  string value = 2 [default = "foo"];
+}
+```
+
+The following Swift code would act as commented, where setting deeply nested
+properties causes the copies and mutations to occur as the assignment statement
+is unwound:
+
+```swift
+var node = Node()
+
+let s = node.child.child.value
+// 1. node.child returns the "default Node".
+// 2. Reading .child on the result of (1) returns the same default Node.
+// 3. Reading .value on the result of (2) returns the default value "foo".
+
+node.child.child.value = "bar"
+// 4. Setting .value on the default Node causes a copy to be made and sets
+//    the property on that copy. Subsequently, the language updates the
+//    value of "node.child.child" to point to that copy.
+// 5. Updating "node.child.child" in (4) requires another copy, because
+//    "node.child" was also the instance of the default node. The copy is
+//    assigned back to "node.child".
+// 6. Setting "node.child" in (5) is a simple value reassignment, since
+//    "node" is a mutable var.
+```
+
+In other words, the generated messages do not internally have to manage parental
+relationships to backfill the appropriate properties on mutation. Swift provides
+this for free.
+
+## Scalar value fields
+
+Proto scalar value fields will map to Swift types in the following way:
+
+.proto Type | Swift Type
+----------- | -------------------
+`double`    | `Double`
+`float`     | `Float`
+`int32`     | `Int32`
+`int64`     | `Int64`
+`uint32`    | `UInt32`
+`uint64`    | `UInt64`
+`sint32`    | `Int32`
+`sint64`    | `Int64`
+`fixed32`   | `UInt32`
+`fixed64`   | `UInt64`
+`sfixed32`  | `Int32`
+`sfixed64`  | `Int64`
+`bool`      | `Bool`
+`string`    | `String`
+`bytes`     | `Foundation.NSData`
+
+The proto spec defines a number of integral types that map to the same Swift
+type; for example, `intXX`, `sintXX`, and `sfixedXX` are all signed integers,
+and `uintXX` and `fixedXX` are both unsigned integers. No other language
+implementation distinguishes these further, so we do not do so either. The
+rationale is that the various types only serve to distinguish how the value is
+**encoded on the wire**; once loaded in memory, the user is not concerned about
+these variations.
+
+Swift’s lack of implicit conversions among types will make it slightly annoying
+to use these types in a context expecting an `Int`, or vice-versa, but since
+this is a data-interchange format with explicitly-sized fields, we should not
+hide that information from the user. Users will have to explicitly write
+`Int(message.myField)`, for example.
+
+## Embedded message fields
+
+Embedded message fields can be represented using an optional variable of the
+generated message type. Thus, the message
+
+```protobuf
+message Foo {
+  Bar bar = 1;
+}
+```
+
+would be represented in Swift as
+
+```swift
+public struct Foo: ProtoMessage {
+  public var bar: Bar! {
+    get { ... }
+    set { ... }
+  }
+}
+```
+
+If the user explicitly sets `bar` to nil, or if it was never set when read from
+the wire, retrieving the value of `bar` would return a default, statically
+allocated instance of `Bar` containing default values for its fields. This
+achieves the desired behavior for default values in the same way that scalar
+fields are designed, and also allows users to deep-drill into complex object
+graphs to get or set fields without checking for nil at each step.
+
+## Enum fields
+
+The design and implementation of enum fields will differ somewhat drastically
+depending on whether the message being generated is a proto2 or proto3 message.
+
+### proto2 enums
+
+For proto2, we do not need to be concerned about unknown enum values, so we can
+use the simple raw-value enum syntax provided by Swift. So the following enum in
+proto2:
+
+```protobuf
+enum ContentType {
+  TEXT = 0;
+  IMAGE = 1;
+}
+```
+
+would become this Swift enum:
+
+```swift
+public enum ContentType: Int32, NilLiteralConvertible {
+  case text = 0
+  case image = 1
+
+  public init(nilLiteral: ()) {
+    self = .text
+  }
+}
+```
+
+See below for the discussion about `NilLiteralConvertible`.
+
+### proto3 enums
+
+For proto3, we need to be able to preserve unknown enum values that may come
+across the wire so that they can be written back if unmodified. We can
+accomplish this in Swift by using a case with an associated value for unknowns.
+So the following enum in proto3:
+
+```protobuf
+enum ContentType {
+  TEXT = 0;
+  IMAGE = 1;
+}
+```
+
+would become this Swift enum:
+
+```swift
+public enum ContentType: RawRepresentable, NilLiteralConvertible {
+  case text
+  case image
+  case UNKNOWN_VALUE(Int32)
+
+  public typealias RawValue = Int32
+
+  public init(nilLiteral: ()) {
+    self = .text
+  }
+
+  public init(rawValue: RawValue) {
+    switch rawValue {
+      case 0: self = .text
+      case 1: self = .image
+      default: self = .UNKNOWN_VALUE(rawValue)
+  }
+
+  public var rawValue: RawValue {
+    switch self {
+      case .text: return 0
+      case .image: return 1
+      case .UNKNOWN_VALUE(let value): return value
+    }
+  }
+}
+```
+
+Note that the use of a parameterized case prevents us from inheriting from the
+raw `Int32` type; Swift does not allow an enum with a raw type to have cases
+with arguments. Instead, we must implement the raw value initializer and
+computed property manually. The `UNKNOWN_VALUE` case is explicitly chosen to be
+"ugly" so that it stands out and does not conflict with other possible case
+names.
+
+Using this approach, proto3 consumers must always have a default case or handle
+the `.UNKNOWN_VALUE` case to satisfy case exhaustion in a switch statement; the
+Swift compiler considers it an error if switch statements are not exhaustive.
+
+### NilLiteralConvertible conformance
+
+This is required to clean up the usage of enum-typed properties in switch
+statements. Unlike other field types, enum properties cannot be
+implicitly-unwrapped optionals without requiring that uses in switch statements
+be explicitly unwrapped. For example, if we consider a message with the enum
+above, this usage will fail to compile:
+
+```swift
+// Without NilLiteralConvertible conformance on ContentType
+public struct SomeMessage: ProtoMessage {
+  public var contentType: ContentType! { ... }
+}
+
+// ERROR: no case named text or image
+switch someMessage.contentType {
+  case .text: { ... }
+  case .image: { ... }
+}
+```
+
+Even though our implementation guarantees that `contentType` will never be nil,
+if it is an optional type, its cases would be `some` and `none`, not the cases
+of the underlying enum type. In order to use it in this context, the user must
+write `someMessage.contentType!` in their switch statement.
+
+Making the enum itself `NilLiteralConvertible` permits us to make the property
+non-optional, so the user can still set it to nil to clear it (i.e., reset it to
+its default value), while eliminating the need to explicitly unwrap it in a
+switch statement.
+
+```swift
+// With NilLiteralConvertible conformance on ContentType
+public struct SomeMessage: ProtoMessage {
+  // Note that the property type is no longer optional
+  public var contentType: ContentType { ... }
+}
+
+// OK: Compiles and runs as expected
+switch someMessage.contentType {
+  case .text: { ... }
+  case .image: { ... }
+}
+
+// The enum can be reset to its default value this way
+someMessage.contentType = nil
+```
+
+One minor oddity with this approach is that nil will be auto-converted to the
+default value of the enum in any context, not just field assignment. In other
+words, this is valid:
+
+```swift
+func foo(contentType: ContentType) { ... }
+foo(nil) // Inside foo, contentType == .text
+```
+
+That being said, the advantage of being able to simultaneously support
+nil-resettability and switch-without-unwrapping outweighs this side effect,
+especially if appropriately documented. It is our hope that a new form of
+resettable properties will be added to Swift that eliminates this inconsistency.
+Some community members have already drafted or sent proposals for review that
+would benefit our designs:
+
+*   [SE-0030: Property Behaviors]
+    (https://github.com/apple/swift-evolution/blob/master/proposals/0030-property-behavior-decls.md)
+*   [Drafted: Resettable Properties]
+    (https://github.com/patters/swift-evolution/blob/master/proposals/0000-resettable-properties.md)
+
+### Enum aliases
+
+The `allow_alias` option in protobuf slightly complicates the use of Swift enums
+to represent that type, because raw values of cases in an enum must be unique.
+Swift lets us define static variables in an enum that alias actual cases. For
+example, the following protobuf enum:
+
+```protobuf
+enum Foo {
+  option allow_alias = true;
+  BAR = 0;
+  BAZ = 0;
+}
+```
+
+will be represented in Swift as:
+
+```swift
+public enum Foo: Int32, NilLiteralConvertible {
+  case bar = 0
+  static public let baz = bar
+
+  // ... etc.
+}
+
+// Can still use .baz shorthand to reference the alias in contexts
+// where the type is inferred
+```
+
+That is, we use the first name as the actual case and use static variables for
+the other aliases. One drawback to this approach is that the static aliases
+cannot be used as cases in a switch statement (the compiler emits the error
+*“Enum case ‘baz’ not found in type ‘Foo’”*). However, in our own code bases,
+there are only a few places where enum aliases are not mere renamings of an
+older value, but they also don’t appear to be the type of value that one would
+expect to switch on (for example, a group of named constants representing
+metrics rather than a set of options), so this restriction is not significant.
+
+This strategy also implies that changing the name of an enum and adding the old
+name as an alias below the new name will be a breaking change in the generated
+Swift code.
+
+## Oneof types
+
+The `oneof` feature represents a “variant/union” data type that maps nicely to
+Swift enums with associated values (algebraic types). These fields can also be
+accessed independently though, and, specifically in the case of proto2, it’s
+reasonable to expect access to default values when accessing a field that is not
+explicitly set.
+
+Taking all this into account, we can represent a `oneof` in Swift with two sets
+of constructs:
+
+*   Properties in the message that correspond to the `oneof` fields.
+*   A nested enum named after the `oneof` and which provides the corresponding
+    field values as case arguments.
+
+This approach fulfills the needs of proto consumers by providing a
+Swift-idiomatic way of simultaneously checking which field is set and accessing
+its value, providing individual properties to access the default values
+(important for proto2), and safely allows a field to be moved into a `oneof`
+without breaking clients.
+
+Consider the following proto:
+
+```protobuf
+message MyMessage {
+  oneof record {
+    string name = 1 [default = "unnamed"];
+    int32 id_number = 2 [default = 0];
+  }
+}
+```
+
+In Swift, we would generate an enum, a property for that enum, and properties
+for the fields themselves:
+
+```swift
+public struct MyMessage: ProtoMessage {
+  public enum Record: NilLiteralConvertible {
+    case name(String)
+    case idNumber(Int32)
+    case NOT_SET
+
+    public init(nilLiteral: ()) { self = .NOT_SET }
+  }
+
+  // This is the "Swifty" way of accessing the value
+  public var record: Record { ... }
+
+  // Direct access to the underlying fields
+  public var name: String! { ... }
+  public var idNumber: Int32! { ... }
+}
+```
+
+This makes both usage patterns possible:
+
+```swift
+// Usage 1: Case-based dispatch
+switch message.record {
+  case .name(let name):
+    // Do something with name if it was explicitly set
+  case .idNumber(let id):
+    // Do something with id_number if it was explicitly set
+  case .NOT_SET:
+    // Do something if it’s not set
+}
+
+// Usage 2: Direct access for default value fallback
+// Sets the label text to the name if it was explicitly set, or to
+// "unnamed" (the default value for the field) if id_number was set
+// instead
+let myLabel = UILabel()
+myLabel.text = message.name
+```
+
+As with proto enums, the generated `oneof` enum conforms to
+`NilLiteralConvertible` to avoid switch statement issues. Setting the property
+to nil will clear it (i.e., reset it to `NOT_SET`).
+
+## Unknown Fields (proto2 only)
+
+To be written.
+
+## Extensions (proto2 only)
+
+To be written.
+
+## Reflection and Descriptors
+
+We will not include reflection or descriptors in the first version of the Swift
+library. The use cases for reflection on mobile are not as strong and the static
+data to represent the descriptors would add bloat when we wish to keep the code
+size small.
+
+In the future, we will investigate whether they can be included as extensions
+which might be able to be excluded from a build and/or automatically dead
+stripped by the compiler if they are not used.
+
+## Appendix A: Rejected strategies to handle packages
+
+### Each package is its own Swift module
+
+Each proto package could be declared as its own Swift module, replacing dots
+with underscores (e.g., package `foo.bar` becomes module `Foo_Bar`). Then, users
+would simply import modules containing whatever proto modules they want to use
+and refer to the generated types by their short names.
+
+**This solution is simply not possible, however.** Swift modules cannot
+circularly reference each other, but there is no restriction against proto
+packages doing so. Circular imports are forbidden (e.g., `foo.proto` importing
+`bar.proto` importing `foo.proto`), but nothing prevents package `foo` from
+using a type in package `bar` which uses a different type in package `foo`, as
+long as there is no import cycle. If these packages were generated as Swift
+modules, then `Foo` would contain an `import Bar` statement and `Bar` would
+contain an `import Foo` statement, and there is no way to compile this.
+
+### Ad hoc namespacing with structs
+
+We can “fake” namespaces in Swift by declaring empty structs with private
+initializers. Since modules are constructed based on compiler arguments, not by
+syntactic constructs, and because there is no pure Swift way to define
+submodules (even though Clang module maps support this), there is no
+source-drive way to group generated code into namespaces aside from this
+approach.
+
+Types can be added to those intermediate package structs using Swift extensions.
+For example, a message `Baz` in package `foo.bar` could be represented in Swift
+as follows:
+
+```swift
+public struct Foo {
+  private init() {}
+}
+
+public extension Foo {
+  public struct Bar {
+    private init() {}
+  }
+}
+
+public extension Foo.Bar {
+  public struct Baz {
+    // Message fields and other methods
+  }
+}
+
+let baz = Foo.Bar.Baz()
+```
+
+Each of these constructs would actually be defined in a separate file; Swift
+lets us keep them separate and add multiple structs to a single “namespace”
+through extensions.
+
+Unfortunately, these intermediate structs generate symbols of their own
+(metatype information in the data segment). This becomes problematic if multiple
+build targets contain Swift sources generated from different messages in the
+same package. At link time, these symbols would collide, resulting in multiple
+definition errors.
+
+This approach also has the disadvantage that there is no automatic “short” way
+to refer to the generated messages at the deepest nesting levels; since this use
+of structs is a hack around the lack of namespaces, there is no equivalent to
+import (Java) or using (C++) to simplify this. Users would have to declare type
+aliases to make this cleaner, or we would have to generate them for users.
diff --git a/docs/third_party.md b/docs/third_party.md
new file mode 100644
index 00000000..69ed6a38
--- /dev/null
+++ b/docs/third_party.md
@@ -0,0 +1,147 @@
+# Third-Party Add-ons for Protocol Buffers
+
+This page lists code related to Protocol Buffers which is developed and maintained by third parties.  You may find this code useful, but note that **these projects are not affiliated with or endorsed by Google (unless explicitly marked)**; try them at your own risk.  Also note that many projects here are in the early stages of development and not production-ready.
+
+If you have a project that should be listed here, please [send us a pull request](https://github.com/google/protobuf/pulls) to update this page.
+
+## Programming Languages
+
+These are projects we know about implementing Protocol Buffers for other programming languages:
+* Action Script: http://code.google.com/p/protobuf-actionscript3/
+* Action Script: https://code.google.com/p/protoc-gen-as3/
+* Action Script: https://github.com/matrix3d/JProtoc
+* C: https://github.com/protobuf-c/protobuf-c
+* C: http://koti.kapsi.fi/jpa/nanopb/
+* C: https://github.com/cloudwu/pbc/
+* C: https://github.com/haberman/upb/wiki
+* C: https://github.com/squidfunk/protobluff
+* C++: https://github.com/google/protobuf (Google-official implementation)
+* C/C++: http://spbc.sf.net/
+* C#: http://code.google.com/p/protobuf-csharp-port
+* C#: http://code.google.com/p/protosharp/
+* C#: https://silentorbit.com/protobuf/
+* C#/.NET/WCF/VB: http://code.google.com/p/protobuf-net/
+* Clojure: http://github.com/ninjudd/clojure-protobuf
+* Common Lisp: http://www.prism.gatech.edu/~ndantam3/docs/s-protobuf/
+* Common Lisp: http://github.com/brown/protobuf
+* D: https://github.com/msoucy/dproto
+* D: http://256.makerslocal.org/wiki/index.php/ProtocolBuffer
+* D: https://github.com/opticron/ProtocolBuffer
+* Dart: https://github.com/dart-lang/dart-protobuf (runtime) https://github.com/dart-lang/dart-protoc-plugin (code generator)
+* Delphi: http://sourceforge.net/projects/protobuf-delphi/
+* Delphi: http://fundementals.sourceforge.net/dl.html
+* Elixir: https://github.com/jeremyong/exprotoc
+* Erlang: http://github.com/ngerakines/erlang_protobuffs/tree/master
+* Erlang: http://piqi.org/
+* Erlang: https://code.google.com/p/protoc-gen-erl/
+* Erlang: https://github.com/basho/erlang_protobuffs
+* Go: https://github.com/golang/protobuf (Google-official implementation)
+* Go: http://code.google.com/p/goprotobuf/
+* Go: https://github.com/akunspy/gopbuf
+* Haskell: http://hackage.haskell.org/package/hprotoc
+* Haxe: https://github.com/Atry/protoc-gen-haxe
+* Java: https://github.com/google/protobuf (Google-official implementation)
+* Java/Android: https://github.com/square/wire
+* Java ME: http://code.google.com/p/protobuf-javame/
+* Java ME: http://swingme.sourceforge.net/encode.shtml
+* Java ME: http://github.com/ponderingpanda/protobuf-j2me
+* Java ME: http://code.google.com/p/protobuf-j2me/
+* Javascript: http://code.google.com/p/protobuf-js/
+* Javascript: http://github.com/sirikata/protojs
+* Javascript: https://github.com/dcodeIO/ProtoBuf.js
+* Javascript: http://code.google.com/p/protobuf-for-node/
+* Javascript: http://code.google.com/p/protostuff/
+* Julia: https://github.com/tanmaykm/ProtoBuf.jl
+* Lua: http://code.google.com/p/protoc-gen-lua/
+* Lua: http://github.com/indygreg/lua-protobuf
+* Lua: https://github.com/Neopallium/lua-pb
+* Matlab: http://code.google.com/p/protobuf-matlab/
+* Mercury: http://code.google.com/p/protobuf-mercury/
+* Objective C: http://code.google.com/p/protobuf-objc/
+* Objective C: https://github.com/alexeyxo/protobuf-objc
+* OCaml: http://piqi.org/
+* Perl: http://groups.google.com/group/protobuf-perl
+* Perl: http://search.cpan.org/perldoc?Google::ProtocolBuffers
+* Perl/XS: http://code.google.com/p/protobuf-perlxs/
+* PHP: http://code.google.com/p/pb4php/
+* PHP: https://github.com/allegro/php-protobuf/
+* PHP: https://github.com/chobie/php-protocolbuffers
+* PHP: http://drslump.github.com/Protobuf-PHP
+* Prolog: http://www.swi-prolog.org/pldoc/package/protobufs.html
+* Python: https://github.com/google/protobuf (Google-official implementation)
+* Python: http://eigenein.github.com/protobuf/
+* R: http://cran.r-project.org/package=RProtoBuf
+* Ruby: http://code.google.com/p/ruby-protobuf/
+* Ruby: http://github.com/mozy/ruby-protocol-buffers
+* Ruby: https://github.com/bmizerany/beefcake/tree/master/lib/beefcake
+* Ruby: https://github.com/localshred/protobuf
+* Rust: https://github.com/stepancheg/rust-protobuf/
+* Scala: http://github.com/jeffplaisance/scala-protobuf
+* Scala: http://code.google.com/p/protobuf-scala
+* Scala: https://github.com/SandroGrzicic/ScalaBuff
+* Scala: http://trueaccord.github.io/ScalaPB/
+* Swift: https://github.com/alexeyxo/protobuf-swift
+* Vala: https://launchpad.net/protobuf-vala
+* Visual Basic: http://code.google.com/p/protobuf-net/
+
+## RPC Implementations
+
+GRPC (http://www.grpc.io/) is Google's RPC implementation for Protocol Buffers. There are other third-party RPC implementations as well.  Some of these actually work with Protocol Buffers service definitions (defined using the `service` keyword in `.proto` files) while others just use Protocol Buffers message objects.
+
+* https://github.com/grpc/grpc (C++, Node.js, Python, Ruby, Objective-C, PHP, C#, Google-official implementation)
+* http://zeroc.com/ice.html (Multiple languages)
+* http://code.google.com/p/protobuf-net/ (C#/.NET/WCF/VB)
+* https://launchpad.net/txprotobuf/ (Python)
+* https://github.com/modeswitch/protobuf-rpc (Python)
+* http://code.google.com/p/protobuf-socket-rpc/ (Java, Python)
+* http://code.google.com/p/proto-streamer/ (Java)
+* http://code.google.com/p/server1/ (C++)
+* http://deltavsoft.com/RcfUserGuide/Protobufs (C++)
+* http://code.google.com/p/protobuf-mina-rpc/ (Python client, Java server)
+* http://code.google.com/p/casocklib/ (C++)
+* http://code.google.com/p/cxf-protobuf/ (Java)
+* http://code.google.com/p/protobuf-remote/ (C++/C#)
+* http://code.google.com/p/protobuf-rpc-pro/ (Java)
+* https://code.google.com/p/protorpc/ (Go/C++)
+* https://code.google.com/p/eneter-protobuf-serializer/ (Java/.NET)
+* http://www.deltavsoft.com/RCFProto.html (C++/Java/Python/C#)
+* https://github.com/robbinfan/claire-protorpc (C++)
+* https://github.com/BaiduPS/sofa-pbrpc (C++)
+* https://github.com/ebencheung/arab (C++)
+* http://code.google.com/p/protobuf-csharp-rpc/ (C#)
+* https://github.com/thesamet/rpcz (C++/Python, based on ZeroMQ)
+* https://github.com/w359405949/libmaid (C++, Python)
+* https://github.com/madwyn/libpbrpc (C++)
+
+## Other Utilities
+
+There are miscellaneous other things you may find useful as a Protocol Buffers developer.
+
+* [NetBeans IDE plugin](http://code.google.com/p/protobuf-netbeans-plugin/)
+* [Wireshark/Ethereal packet sniffer plugin](http://code.google.com/p/protobuf-wireshark/)
+* [Alternate encodings (JSON, XML, HTML) for Java protobufs](http://code.google.com/p/protobuf-java-format/)
+* [Another JSON encoder/decoder for Java](https://github.com/sijuv/protobuf-codec)
+* [Editor for serialized protobufs](http://code.google.com/p/protobufeditor/)
+* [Intellij IDEA plugin](http://github.com/nnmatveev/idea-plugin-protobuf)
+* [TextMate syntax highlighting](http://github.com/michaeledgar/protobuf-tmbundle)
+* [Oracle PL SQL plugin](http://code.google.com/p/protocol-buffer-plsql/)
+* [Eclipse editor for protobuf (from Google)](http://code.google.com/p/protobuf-dt/)
+* [C++ Builder compatible protobuf](https://github.com/saadware/protobuf-cppbuilder)
+* Maven Protocol Compiler Plugin
+    * https://github.com/sergei-ivanov/maven-protoc-plugin/
+    * http://igor-petruk.github.com/protobuf-maven-plugin/
+    * http://code.google.com/p/maven-protoc-plugin/
+    * https://github.com/os72/protoc-jar-maven-plugin
+* [Documentation generator plugin (Markdown/HTML/DocBook/...)](https://github.com/estan/protoc-gen-doc)
+* [DocBook generator for .proto files](http://code.google.com/p/protoc-gen-docbook/)
+* [Protobuf for nginx module](https://github.com/dbcode/protobuf-nginx/)
+* [RSpec matchers and Cucumber step defs for testing Protocol Buffers](https://github.com/connamara/protobuf_spec)
+* [Sbt plugin for Protocol Buffers](https://github.com/Atry/sbt-cppp)
+* [Gradle Protobuf Plugin](https://github.com/aantono/gradle-plugin-protobuf)
+* [Multi-platform executable JAR and Java API for protoc](https://github.com/os72/protoc-jar)
+* [Python scripts to convert between Protocol Buffers and JSON](https://github.com/NextTuesday/py-pb-converters)
+* [Visual Studio Language Service support for Protocol Buffers](http://visualstudiogallery.msdn.microsoft.com/4bc0f38c-b058-4e05-ae38-155e053c19c5)
+* [C++ library for serialization/de-serialization between Protocol Buffers and JSON.](https://github.com/yinqiwen/pbjson)
+* [ProtoBuf with Java EE7 Expression Language 3.0; pure Java ProtoBuf Parser and Builder.](https://github.com/protobufel/protobuf-el)
+* [Notepad++ Syntax Highlighting for .proto files](https://github.com/chai2010/notepadplus-protobuf)
+* [Linter for .proto files](https://github.com/ckaznocha/protoc-gen-lint)
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
index 9f418f2b..03c0d579 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -50,17 +50,23 @@ import java.util.Map;
  *
  * @author kenton@google.com Kenton Varda
  */
-public abstract class AbstractMessage extends AbstractMessageLite
-                                      implements Message {
+public abstract class AbstractMessage
+    // TODO(dweis): Update GeneratedMessage to parameterize with MessageType and BuilderType.
+    extends AbstractMessageLite
+    implements Message {
+  
+  @Override
   public boolean isInitialized() {
     return MessageReflection.isInitialized(this);
   }
 
 
+  @Override
   public List<String> findInitializationErrors() {
     return MessageReflection.findMissingFields(this);
   }
 
+  @Override
   public String getInitializationErrorString() {
     return MessageReflection.delimitWithCommas(findInitializationErrors());
   }
@@ -83,12 +89,14 @@ public abstract class AbstractMessage extends AbstractMessageLite
     return TextFormat.printToString(this);
   }
 
+  @Override
   public void writeTo(final CodedOutputStream output) throws IOException {
     MessageReflection.writeMessageTo(this, getAllFields(), output, false);
   }
 
   protected int memoizedSize = -1;
 
+  @Override
   public int getSerializedSize() {
     int size = memoizedSize;
     if (size != -1) {
@@ -288,8 +296,8 @@ public abstract class AbstractMessage extends AbstractMessageLite
    * other methods.
    */
   @SuppressWarnings("unchecked")
-  public static abstract class Builder<BuilderType extends Builder>
-      extends AbstractMessageLite.Builder<BuilderType>
+  public static abstract class Builder<BuilderType extends Builder<BuilderType>>
+      extends AbstractMessageLite.Builder
       implements Message.Builder {
     // The compiler produces an error if this is not declared explicitly.
     @Override
@@ -314,6 +322,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
       throw new UnsupportedOperationException("clearOneof() is not implemented.");
     }
 
+    @Override
     public BuilderType clear() {
       for (final Map.Entry<FieldDescriptor, Object> entry :
            getAllFields().entrySet()) {
@@ -322,14 +331,22 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public List<String> findInitializationErrors() {
       return MessageReflection.findMissingFields(this);
     }
 
+    @Override
     public String getInitializationErrorString() {
       return MessageReflection.delimitWithCommas(findInitializationErrors());
     }
+    
+    @Override
+    protected BuilderType internalMergeFrom(AbstractMessageLite other) {
+      return mergeFrom((Message) other);
+    }
 
+    @Override
     public BuilderType mergeFrom(final Message other) {
       if (other.getDescriptorForType() != getDescriptorForType()) {
         throw new IllegalArgumentException(
@@ -407,6 +424,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
       setUnknownFields(
         UnknownFieldSet.newBuilder(getUnknownFields())
@@ -415,17 +433,19 @@ public abstract class AbstractMessage extends AbstractMessageLite
       return (BuilderType) this;
     }
 
+    @Override
     public Message.Builder getFieldBuilder(final FieldDescriptor field) {
       throw new UnsupportedOperationException(
           "getFieldBuilder() called on an unsupported message type.");
     }
 
-    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field,
-        int index) {
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
       throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on an unsupported message type.");
     }
 
+    @Override
     public String toString() {
       return TextFormat.printToString(this);
     }
@@ -462,7 +482,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
     @Override
     public BuilderType mergeFrom(final ByteString data)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data);
+      return (BuilderType) super.mergeFrom(data);
     }
 
     @Override
@@ -470,20 +490,20 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final ByteString data,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
     }
 
     @Override
     public BuilderType mergeFrom(final byte[] data)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data);
+      return (BuilderType) super.mergeFrom(data);
     }
 
     @Override
     public BuilderType mergeFrom(
         final byte[] data, final int off, final int len)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, off, len);
+      return (BuilderType) super.mergeFrom(data, off, len);
     }
 
     @Override
@@ -491,7 +511,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final byte[] data,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
     }
 
     @Override
@@ -499,13 +519,13 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final byte[] data, final int off, final int len,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
-      return super.mergeFrom(data, off, len, extensionRegistry);
+      return (BuilderType) super.mergeFrom(data, off, len, extensionRegistry);
     }
 
     @Override
     public BuilderType mergeFrom(final InputStream input)
         throws IOException {
-      return super.mergeFrom(input);
+      return (BuilderType) super.mergeFrom(input);
     }
 
     @Override
@@ -513,7 +533,7 @@ public abstract class AbstractMessage extends AbstractMessageLite
         final InputStream input,
         final ExtensionRegistryLite extensionRegistry)
         throws IOException {
-      return super.mergeFrom(input, extensionRegistry);
+      return (BuilderType) super.mergeFrom(input, extensionRegistry);
     }
 
     @Override
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java b/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
index 12384983..43736dd1 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java
@@ -43,9 +43,13 @@ import java.util.Collection;
  *
  * @author kenton@google.com Kenton Varda
  */
-public abstract class AbstractMessageLite implements MessageLite {
+public abstract class AbstractMessageLite<
+    MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+    BuilderType extends AbstractMessageLite.Builder<MessageType, BuilderType>> 
+        implements MessageLite {
   protected int memoizedHashCode = 0;
-
+  
+  @Override
   public ByteString toByteString() {
     try {
       final ByteString.CodedBuilder out =
@@ -59,6 +63,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     }
   }
 
+  @Override
   public byte[] toByteArray() {
     try {
       final byte[] result = new byte[getSerializedSize()];
@@ -73,6 +78,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     }
   }
 
+  @Override
   public void writeTo(final OutputStream output) throws IOException {
     final int bufferSize =
         CodedOutputStream.computePreferredBufferSize(getSerializedSize());
@@ -82,6 +88,7 @@ public abstract class AbstractMessageLite implements MessageLite {
     codedOutput.flush();
   }
 
+  @Override
   public void writeDelimitedTo(final OutputStream output) throws IOException {
     final int serialized = getSerializedSize();
     final int bufferSize = CodedOutputStream.computePreferredBufferSize(
@@ -120,25 +127,27 @@ public abstract class AbstractMessageLite implements MessageLite {
    * other methods.
    */
   @SuppressWarnings("unchecked")
-  public static abstract class Builder<BuilderType extends Builder>
+  public abstract static class Builder<
+      MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+      BuilderType extends Builder<MessageType, BuilderType>>
       implements MessageLite.Builder {
     // The compiler produces an error if this is not declared explicitly.
     @Override
     public abstract BuilderType clone();
 
-    public BuilderType mergeFrom(final CodedInputStream input)
-                                 throws IOException {
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
       return mergeFrom(input, ExtensionRegistryLite.getEmptyRegistry());
     }
 
     // Re-defined here for return type covariance.
+    @Override
     public abstract BuilderType mergeFrom(
-        final CodedInputStream input,
-        final ExtensionRegistryLite extensionRegistry)
+        final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
         throws IOException;
 
-    public BuilderType mergeFrom(final ByteString data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
         mergeFrom(input);
@@ -153,9 +162,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final ByteString data,
-        final ExtensionRegistryLite extensionRegistry)
+        final ByteString data, final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
@@ -171,14 +180,14 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
-    public BuilderType mergeFrom(final byte[] data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
       return mergeFrom(data, 0, data.length);
     }
 
-    public BuilderType mergeFrom(final byte[] data, final int off,
-                                 final int len)
-                                 throws InvalidProtocolBufferException {
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final int off, final int len)
+        throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input =
             CodedInputStream.newInstance(data, off, len);
@@ -194,15 +203,17 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
-    public BuilderType mergeFrom(
-        final byte[] data,
-        final ExtensionRegistryLite extensionRegistry)
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       return mergeFrom(data, 0, data.length, extensionRegistry);
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final byte[] data, final int off, final int len,
+        final byte[] data,
+        final int off,
+        final int len,
         final ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       try {
@@ -220,6 +231,7 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public BuilderType mergeFrom(final InputStream input) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput);
@@ -227,10 +239,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       return (BuilderType) this;
     }
 
+    @Override
     public BuilderType mergeFrom(
-        final InputStream input,
-        final ExtensionRegistryLite extensionRegistry)
-        throws IOException {
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput, extensionRegistry);
       codedInput.checkLastTagWas(0);
@@ -292,10 +303,9 @@ public abstract class AbstractMessageLite implements MessageLite {
       }
     }
 
+    @Override
     public boolean mergeDelimitedFrom(
-        final InputStream input,
-        final ExtensionRegistryLite extensionRegistry)
-        throws IOException {
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
       final int firstByte = input.read();
       if (firstByte == -1) {
         return false;
@@ -306,11 +316,24 @@ public abstract class AbstractMessageLite implements MessageLite {
       return true;
     }
 
-    public boolean mergeDelimitedFrom(final InputStream input)
-        throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
       return mergeDelimitedFrom(input,
           ExtensionRegistryLite.getEmptyRegistry());
     }
+    
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public BuilderType mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+            "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+        
+      return internalMergeFrom((MessageType) other);
+    }
+    
+    protected abstract BuilderType internalMergeFrom(MessageType message);
 
     /**
      * Construct an UninitializedMessageException reporting missing fields in
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractParser.java b/java/core/src/main/java/com/google/protobuf/AbstractParser.java
index 1a4c6311..66b0ee3b 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractParser.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractParser.java
@@ -78,26 +78,27 @@ public abstract class AbstractParser<MessageType extends MessageLite>
   private static final ExtensionRegistryLite EMPTY_REGISTRY
       = ExtensionRegistryLite.getEmptyRegistry();
 
+  @Override
   public MessageType parsePartialFrom(CodedInputStream input)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(CodedInputStream input,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(input, extensionRegistry));
   }
 
-  public MessageType parseFrom(CodedInputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(CodedInputStream input) throws InvalidProtocolBufferException {
     return parseFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(ByteString data,
-                                      ExtensionRegistryLite extensionRegistry)
-    throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
     MessageType message;
     try {
       CodedInputStream input = data.newCodedInput();
@@ -113,24 +114,25 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     }
   }
 
-  public MessageType parsePartialFrom(ByteString data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(ByteString data) throws InvalidProtocolBufferException {
     return parsePartialFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(ByteString data,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(parsePartialFrom(data, extensionRegistry));
   }
 
-  public MessageType parseFrom(ByteString data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(ByteString data) throws InvalidProtocolBufferException {
     return parseFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(byte[] data, int off, int len,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     try {
       CodedInputStream input = CodedInputStream.newInstance(data, off, len);
@@ -146,47 +148,50 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     }
   }
 
+  @Override
   public MessageType parsePartialFrom(byte[] data, int off, int len)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(data, off, len, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(byte[] data,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return parsePartialFrom(data, 0, data.length, extensionRegistry);
   }
 
-  public MessageType parsePartialFrom(byte[] data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(byte[] data) throws InvalidProtocolBufferException {
     return parsePartialFrom(data, 0, data.length, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(byte[] data, int off, int len,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(data, off, len, extensionRegistry));
   }
 
+  @Override
   public MessageType parseFrom(byte[] data, int off, int len)
       throws InvalidProtocolBufferException {
     return parseFrom(data, off, len, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(byte[] data,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return parseFrom(data, 0, data.length, extensionRegistry);
   }
 
-  public MessageType parseFrom(byte[] data)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(byte[] data) throws InvalidProtocolBufferException {
     return parseFrom(data, EMPTY_REGISTRY);
   }
 
-  public MessageType parsePartialFrom(InputStream input,
-                                      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parsePartialFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     CodedInputStream codedInput = CodedInputStream.newInstance(input);
     MessageType message = parsePartialFrom(codedInput, extensionRegistry);
@@ -198,26 +203,26 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     return message;
   }
 
-  public MessageType parsePartialFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parsePartialFrom(InputStream input) throws InvalidProtocolBufferException {
     return parsePartialFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseFrom(InputStream input,
-                               ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialFrom(input, extensionRegistry));
   }
 
-  public MessageType parseFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseFrom(InputStream input) throws InvalidProtocolBufferException {
     return parseFrom(input, EMPTY_REGISTRY);
   }
 
+  @Override
   public MessageType parsePartialDelimitedFrom(
-      InputStream input,
-      ExtensionRegistryLite extensionRegistry)
+      InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     int size;
     try {
@@ -233,21 +238,21 @@ public abstract class AbstractParser<MessageType extends MessageLite>
     return parsePartialFrom(limitedInput, extensionRegistry);
   }
 
+  @Override
   public MessageType parsePartialDelimitedFrom(InputStream input)
       throws InvalidProtocolBufferException {
     return parsePartialDelimitedFrom(input, EMPTY_REGISTRY);
   }
 
-  public MessageType parseDelimitedFrom(
-      InputStream input,
-      ExtensionRegistryLite extensionRegistry)
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
       throws InvalidProtocolBufferException {
     return checkMessageInitialized(
         parsePartialDelimitedFrom(input, extensionRegistry));
   }
 
-  public MessageType parseDelimitedFrom(InputStream input)
-      throws InvalidProtocolBufferException {
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input) throws InvalidProtocolBufferException {
     return parseDelimitedFrom(input, EMPTY_REGISTRY);
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java b/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
index bb6446b2..b17db6e0 100644
--- a/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
+++ b/java/core/src/main/java/com/google/protobuf/AbstractProtobufList.java
@@ -34,19 +34,25 @@ import com.google.protobuf.Internal.ProtobufList;
 
 import java.util.AbstractList;
 import java.util.Collection;
+import java.util.List;
+import java.util.RandomAccess;
 
 /**
  * An abstract implementation of {@link ProtobufList} which manages mutability semantics. All mutate
- * methods are check if the list is mutable before proceeding. Subclasses must invoke
+ * methods must check if the list is mutable before proceeding. Subclasses must invoke
  * {@link #ensureIsMutable()} manually when overriding those methods.
+ * <p>
+ * This implementation assumes all subclasses are array based, supporting random access.
  */
 abstract class AbstractProtobufList<E> extends AbstractList<E> implements ProtobufList<E> {
 
+  protected static final int DEFAULT_CAPACITY = 10;
+
   /**
    * Whether or not this list is modifiable.
    */
   private boolean isMutable;
-  
+
   /**
    * Constructs a mutable list by default.
    */
@@ -55,6 +61,44 @@ abstract class AbstractProtobufList<E> extends AbstractList<E> implements Protob
   }
 
   @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof List)) {
+      return false;
+    }
+    // Handle lists that do not support RandomAccess as efficiently as possible by using an iterator
+    // based approach in our super class. Otherwise our index based approach will avoid those
+    // allocations.
+    if (!(o instanceof RandomAccess)) {
+      return super.equals(o);
+    }
+
+    List<?> other = (List<?>) o;
+    final int size = size();
+    if (size != other.size()) {
+      return false;
+    }
+    for (int i = 0; i < size; i++) {
+      if (!get(i).equals(other.get(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    final int size = size();
+    int hashCode = 1;
+    for (int i = 0; i < size; i++) {
+      hashCode = (31 * hashCode) + get(i).hashCode();
+    }
+    return hashCode;
+  }
+
+  @Override
   public boolean add(E e) {
     ensureIsMutable();
     return super.add(e);
diff --git a/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java b/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
index 70e042f5..8b2820b6 100644
--- a/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/BooleanArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.BooleanList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -45,8 +44,6 @@ import java.util.RandomAccess;
 final class BooleanArrayList
     extends AbstractProtobufList<Boolean> implements BooleanList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final BooleanArrayList EMPTY_LIST = new BooleanArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -60,7 +57,7 @@ final class BooleanArrayList
    * The backing store for the list.
    */
   private boolean[] array;
-  
+
   /**
    * The size of the list distinct from the length of the array. That is, it is the number of
    * elements set in the list.
@@ -71,35 +68,57 @@ final class BooleanArrayList
    * Constructs a new mutable {@code BooleanArrayList} with default capacity.
    */
   BooleanArrayList() {
-    this(DEFAULT_CAPACITY);
+    this(new boolean[DEFAULT_CAPACITY], 0);
   }
 
   /**
-   * Constructs a new mutable {@code BooleanArrayList} with the provided capacity.
+   * Constructs a new mutable {@code BooleanArrayList}.
    */
-  BooleanArrayList(int capacity) {
-    array = new boolean[capacity];
-    size = 0;
+  private BooleanArrayList(boolean[] array, int size) {
+    this.array = array;
+    this.size = size;
   }
-
-  /**
-   * Constructs a new mutable {@code BooleanArrayList} containing the same elements as
-   * {@code other}.
-   */
-  BooleanArrayList(List<Boolean> other) {
-    if (other instanceof BooleanArrayList) {
-      BooleanArrayList list = (BooleanArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new boolean[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof BooleanArrayList)) {
+      return super.equals(o);
+    }
+    BooleanArrayList other = (BooleanArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final boolean[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
   }
-  
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Internal.hashBoolean(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public BooleanList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new BooleanArrayList(Arrays.copyOf(array, capacity), size);
+  }
+
   @Override
   public Boolean get(int index) {
     return getBoolean(index);
diff --git a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
index b92394b8..ad174d0f 100644
--- a/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
+++ b/java/core/src/main/java/com/google/protobuf/CodedOutputStream.java
@@ -30,11 +30,18 @@
 
 package com.google.protobuf;
 
+import static java.lang.Math.max;
+
 import com.google.protobuf.Utf8.UnpairedSurrogateException;
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.lang.reflect.Field;
+import java.nio.BufferOverflowException;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import java.security.AccessController;
+import java.security.PrivilegedExceptionAction;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -50,23 +57,21 @@ import java.util.logging.Logger;
  *
  * <p>This class is totally unsynchronized.
  */
-public final class CodedOutputStream {
+public abstract class CodedOutputStream extends ByteOutput {
   private static final Logger logger = Logger.getLogger(CodedOutputStream.class.getName());
+  private static final sun.misc.Unsafe UNSAFE = getUnsafe();
+  private static final boolean HAS_UNSAFE_ARRAY_OPERATIONS = supportsUnsafeArrayOperations();
+  private static final long ARRAY_BASE_OFFSET = byteArrayBaseOffset();
 
-  private static final int LITTLE_ENDIAN_64_SIZE = 8;
+  private static final int FIXED_32_SIZE = 4;
+  private static final int FIXED_64_SIZE = 8;
+  private static final int MAX_VARINT_SIZE = 10;
 
   /**
    * @deprecated Use {@link #computeFixed32SizeNoTag(int)} instead.
    */
-  @Deprecated public static final int LITTLE_ENDIAN_32_SIZE = 4;
-
-  // TODO(dweis): Consider migrating to a ByteBuffer.
-  private final byte[] buffer;
-  private final int limit;
-  private int position;
-  private int totalBytesWritten = 0;
-
-  private final OutputStream output;
+  @Deprecated
+  public static final int LITTLE_ENDIAN_32_SIZE = FIXED_32_SIZE;
 
   /**
    * The buffer size used in {@link #newInstance(OutputStream)}.
@@ -87,34 +92,27 @@ public final class CodedOutputStream {
     return dataLength;
   }
 
-  private CodedOutputStream(final byte[] buffer, final int offset, final int length) {
-    output = null;
-    this.buffer = buffer;
-    position = offset;
-    limit = offset + length;
-  }
-
-  private CodedOutputStream(final OutputStream output, final byte[] buffer) {
-    this.output = output;
-    this.buffer = buffer;
-    position = 0;
-    limit = buffer.length;
-  }
-
   /**
-   * Create a new {@code CodedOutputStream} wrapping the given
-   * {@code OutputStream}.
+   * Create a new {@code CodedOutputStream} wrapping the given {@code OutputStream}.
+   *
+   * <p> NOTE: The provided {@link OutputStream} <strong>MUST NOT</strong> retain access or
+   * modify the provided byte arrays. Doing so may result in corrupted data, which would be
+   * difficult to debug.
    */
   public static CodedOutputStream newInstance(final OutputStream output) {
     return newInstance(output, DEFAULT_BUFFER_SIZE);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} wrapping the given
-   * {@code OutputStream} with a given buffer size.
+   * Create a new {@code CodedOutputStream} wrapping the given {@code OutputStream} with a given
+   * buffer size.
+   *
+   * <p> NOTE: The provided {@link OutputStream} <strong>MUST NOT</strong> retain access or
+   * modify the provided byte arrays. Doing so may result in corrupted data, which would be
+   * difficult to debug.
    */
   public static CodedOutputStream newInstance(final OutputStream output, final int bufferSize) {
-    return new CodedOutputStream(output, new byte[bufferSize]);
+    return new OutputStreamEncoder(output, bufferSize);
   }
 
   /**
@@ -137,160 +135,144 @@ public final class CodedOutputStream {
    */
   public static CodedOutputStream newInstance(
       final byte[] flatArray, final int offset, final int length) {
-    return new CodedOutputStream(flatArray, offset, length);
+    return new ArrayEncoder(flatArray, offset, length);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} that writes to the given ByteBuffer.
+   * Create a new {@code CodedOutputStream} that writes to the given {@link ByteBuffer}.
    */
   public static CodedOutputStream newInstance(ByteBuffer byteBuffer) {
-    return newInstance(byteBuffer, DEFAULT_BUFFER_SIZE);
+    if (byteBuffer.hasArray()) {
+      return new NioHeapEncoder(byteBuffer);
+    }
+    return new NioEncoder(byteBuffer);
   }
 
   /**
-   * Create a new {@code CodedOutputStream} that writes to the given ByteBuffer.
+   * Create a new {@code CodedOutputStream} that writes to the given {@link ByteBuffer}.
+   *
+   * @deprecated the size parameter is no longer used since use of an internal buffer is useless
+   * (and wasteful) when writing to a {@link ByteBuffer}. Use {@link #newInstance(ByteBuffer)}
+   * instead.
    */
-  public static CodedOutputStream newInstance(ByteBuffer byteBuffer, int bufferSize) {
-    return newInstance(new ByteBufferOutputStream(byteBuffer), bufferSize);
+  @Deprecated
+  public static CodedOutputStream newInstance(ByteBuffer byteBuffer,
+      @SuppressWarnings("unused") int unused) {
+    return newInstance(byteBuffer);
   }
 
-  private static class ByteBufferOutputStream extends OutputStream {
-    private final ByteBuffer byteBuffer;
-
-    public ByteBufferOutputStream(ByteBuffer byteBuffer) {
-      this.byteBuffer = byteBuffer;
+  /**
+   * Create a new {@code CodedOutputStream} that writes to the provided {@link ByteOutput}.
+   *
+   * <p> NOTE: The {@link ByteOutput} <strong>MUST NOT</strong> modify the provided buffers. Doing
+   * so may result in corrupted data, which would be difficult to debug.
+   *
+   * @param byteOutput the output target for encoded bytes.
+   * @param bufferSize the size of the internal scratch buffer to be used for string encoding.
+   * Setting this to {@code 0} will disable buffering, requiring an allocation for each encoded
+   * string.
+   */
+  static CodedOutputStream newInstance(ByteOutput byteOutput, int bufferSize) {
+    if (bufferSize < 0) {
+      throw new IllegalArgumentException("bufferSize must be positive");
     }
 
-    @Override
-    public void write(int b) throws IOException {
-      byteBuffer.put((byte) b);
-    }
+    return new ByteOutputEncoder(byteOutput, bufferSize);
+  }
 
-    @Override
-    public void write(byte[] data, int offset, int length) throws IOException {
-      byteBuffer.put(data, offset, length);
-    }
+  // Disallow construction outside of this class.
+  private CodedOutputStream() {
   }
 
   // -----------------------------------------------------------------
 
   /** Encode and write a tag. */
-  public void writeTag(final int fieldNumber, final int wireType) throws IOException {
-    writeRawVarint32(WireFormat.makeTag(fieldNumber, wireType));
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeTag(int fieldNumber, int wireType) throws IOException;
 
   /** Write an {@code int32} field, including tag, to the stream. */
-  public void writeInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeInt32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeInt32(int fieldNumber, int value) throws IOException;
 
   /** Write a {@code uint32} field, including tag, to the stream. */
-  public void writeUInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeUInt32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt32(int fieldNumber, int value) throws IOException;
 
   /** Write a {@code sint32} field, including tag, to the stream. */
-  public void writeSInt32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeSInt32NoTag(value);
+  public final void writeSInt32(final int fieldNumber, final int value) throws IOException {
+    writeUInt32(fieldNumber, encodeZigZag32(value));
   }
 
   /** Write a {@code fixed32} field, including tag, to the stream. */
-  public void writeFixed32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeFixed32NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed32(int fieldNumber, int value) throws IOException;
 
   /** Write an {@code sfixed32} field, including tag, to the stream. */
-  public void writeSFixed32(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeSFixed32NoTag(value);
+  public final void writeSFixed32(final int fieldNumber, final int value) throws IOException {
+    writeFixed32(fieldNumber, value);
   }
 
   /** Write an {@code int64} field, including tag, to the stream. */
-  public void writeInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeInt64NoTag(value);
+  public final void writeInt64(final int fieldNumber, final long value) throws IOException {
+    writeUInt64(fieldNumber, value);
   }
 
   /** Write a {@code uint64} field, including tag, to the stream. */
-  public void writeUInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeUInt64NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt64(int fieldNumber, long value) throws IOException;
 
   /** Write an {@code sint64} field, including tag, to the stream. */
-  public void writeSInt64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeSInt64NoTag(value);
+  public final void writeSInt64(final int fieldNumber, final long value) throws IOException {
+    writeUInt64(fieldNumber, encodeZigZag64(value));
   }
 
   /** Write a {@code fixed64} field, including tag, to the stream. */
-  public void writeFixed64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeFixed64NoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed64(int fieldNumber, long value) throws IOException;
 
   /** Write an {@code sfixed64} field, including tag, to the stream. */
-  public void writeSFixed64(final int fieldNumber, final long value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeSFixed64NoTag(value);
+  public final void writeSFixed64(final int fieldNumber, final long value) throws IOException {
+    writeFixed64(fieldNumber, value);
   }
 
   /** Write a {@code float} field, including tag, to the stream. */
-  public void writeFloat(final int fieldNumber, final float value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
-    writeFloatNoTag(value);
+  public final void writeFloat(final int fieldNumber, final float value) throws IOException {
+    writeFixed32(fieldNumber, Float.floatToRawIntBits(value));
   }
 
   /** Write a {@code double} field, including tag, to the stream. */
-  public void writeDouble(final int fieldNumber, final double value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
-    writeDoubleNoTag(value);
+  public final void writeDouble(final int fieldNumber, final double value) throws IOException {
+    writeFixed64(fieldNumber, Double.doubleToRawLongBits(value));
   }
 
   /** Write a {@code bool} field, including tag, to the stream. */
-  public void writeBool(final int fieldNumber, final boolean value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeBoolNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBool(int fieldNumber, boolean value) throws IOException;
 
   /**
    * Write an enum field, including tag, to the stream. The provided value is the numeric
    * value used to represent the enum value on the wire (not the enum ordinal value).
    */
-  public void writeEnum(final int fieldNumber, final int value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
-    writeEnumNoTag(value);
+  public final void writeEnum(final int fieldNumber, final int value) throws IOException {
+    writeInt32(fieldNumber, value);
   }
 
   /** Write a {@code string} field, including tag, to the stream. */
-  public void writeString(final int fieldNumber, final String value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeStringNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeString(int fieldNumber, String value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeBytesNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBytes(int fieldNumber, ByteString value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteArrayNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteArray(int fieldNumber, byte[] value) throws IOException;
 
   /** Write a {@code bytes} field, including tag, to the stream. */
-  public void writeByteArray(
-      final int fieldNumber, final byte[] value, final int offset, final int length)
-      throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteArrayNoTag(value, offset, length);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteArray(int fieldNumber, byte[] value, int offset, int length)
+      throws IOException;
 
   /**
    * Write a {@code bytes} field, including tag, to the stream.
@@ -302,67 +284,36 @@ public final class CodedOutputStream {
    * of a ByteBuffer, you can call
    * {@code writeByteBuffer(fieldNumber, byteBuffer.slice())}.
    */
-  public void writeByteBuffer(final int fieldNumber, final ByteBuffer value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeByteBufferNoTag(value);
-  }
-
-  /** Write a single byte. */
-  public void writeRawByte(final byte value) throws IOException {
-    if (position == limit) {
-      refreshBuffer();
-    }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeByteBuffer(int fieldNumber, ByteBuffer value) throws IOException;
 
-    buffer[position++] = value;
-    ++totalBytesWritten;
+  /**
+   * Write a single byte.
+   */
+  public final void writeRawByte(final byte value) throws IOException {
+    write(value);
   }
 
   /** Write a single byte, represented by an integer value. */
-  public void writeRawByte(final int value) throws IOException {
-    writeRawByte((byte) value);
+  public final void writeRawByte(final int value) throws IOException {
+    write((byte) value);
   }
 
   /** Write an array of bytes. */
-  public void writeRawBytes(final byte[] value) throws IOException {
-    writeRawBytes(value, 0, value.length);
+  public final void writeRawBytes(final byte[] value) throws IOException {
+    write(value, 0, value.length);
   }
 
-  /** Write part of an array of bytes. */
-  public void writeRawBytes(final byte[] value, int offset, int length) throws IOException {
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      System.arraycopy(value, offset, buffer, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      System.arraycopy(value, offset, buffer, position, bytesWritten);
-      offset += bytesWritten;
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      if (length <= limit) {
-        // Fits in new buffer.
-        System.arraycopy(value, offset, buffer, 0, length);
-        position = length;
-      } else {
-        // Write is very big.  Let's do it all at once.
-        output.write(value, offset, length);
-      }
-      totalBytesWritten += length;
-    }
+  /**
+   * Write part of an array of bytes.
+   */
+  public final void writeRawBytes(final byte[] value, int offset, int length) throws IOException {
+    write(value, offset, length);
   }
 
   /** Write a byte string. */
-  public void writeRawBytes(final ByteString value) throws IOException {
-    writeRawBytes(value, 0, value.size());
+  public final void writeRawBytes(final ByteString value) throws IOException {
+    value.writeTo(this);
   }
 
   /**
@@ -374,155 +325,138 @@ public final class CodedOutputStream {
    * write the remaining bytes of a ByteBuffer, you can call
    * {@code writeRawBytes(byteBuffer.slice())}.
    */
-  public void writeRawBytes(final ByteBuffer value) throws IOException {
-    if (value.hasArray()) {
-      writeRawBytes(value.array(), value.arrayOffset(), value.capacity());
-    } else {
-      ByteBuffer duplicated = value.duplicate();
-      duplicated.clear();
-      writeRawBytesInternal(duplicated);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeRawBytes(final ByteBuffer value) throws IOException;
 
   /** Write an embedded message field, including tag, to the stream. */
-  public void writeMessage(final int fieldNumber, final MessageLite value) throws IOException {
-    writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
-    writeMessageNoTag(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessage(final int fieldNumber, final MessageLite value)
+      throws IOException;
 
   /**
    * Write a MessageSet extension field to the stream.  For historical reasons,
    * the wire format differs from normal fields.
    */
-  public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
-      throws IOException {
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
-    writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
-    writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+      throws IOException;
 
   /**
    * Write an unparsed MessageSet extension field to the stream.  For
    * historical reasons, the wire format differs from normal fields.
    */
-  public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
-      throws IOException {
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
-    writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
-    writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
-    writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+      throws IOException;
 
   // -----------------------------------------------------------------
 
   /** Write an {@code int32} field to the stream. */
-  public void writeInt32NoTag(final int value) throws IOException {
-    if (value >= 0) {
-      writeRawVarint32(value);
-    } else {
-      // Must sign-extend.
-      writeRawVarint64(value);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeInt32NoTag(final int value) throws IOException;
 
   /** Write a {@code uint32} field to the stream. */
-  public void writeUInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt32NoTag(int value) throws IOException;
 
   /** Write a {@code sint32} field to the stream. */
-  public void writeSInt32NoTag(final int value) throws IOException {
-    writeRawVarint32(encodeZigZag32(value));
+  public final void writeSInt32NoTag(final int value) throws IOException {
+    writeUInt32NoTag(encodeZigZag32(value));
   }
 
   /** Write a {@code fixed32} field to the stream. */
-  public void writeFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed32NoTag(int value) throws IOException;
 
   /** Write a {@code sfixed32} field to the stream. */
-  public void writeSFixed32NoTag(final int value) throws IOException {
-    writeRawLittleEndian32(value);
+  public final void writeSFixed32NoTag(final int value) throws IOException {
+    writeFixed32NoTag(value);
   }
 
   /** Write an {@code int64} field to the stream. */
-  public void writeInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(value);
+  public final void writeInt64NoTag(final long value) throws IOException {
+    writeUInt64NoTag(value);
   }
 
   /** Write a {@code uint64} field to the stream. */
-  public void writeUInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeUInt64NoTag(long value) throws IOException;
 
   /** Write a {@code sint64} field to the stream. */
-  public void writeSInt64NoTag(final long value) throws IOException {
-    writeRawVarint64(encodeZigZag64(value));
+  public final void writeSInt64NoTag(final long value) throws IOException {
+    writeUInt64NoTag(encodeZigZag64(value));
   }
 
   /** Write a {@code fixed64} field to the stream. */
-  public void writeFixed64NoTag(final long value) throws IOException {
-    writeRawLittleEndian64(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeFixed64NoTag(long value) throws IOException;
 
   /** Write a {@code sfixed64} field to the stream. */
-  public void writeSFixed64NoTag(final long value) throws IOException {
-    writeRawLittleEndian64(value);
+  public final void writeSFixed64NoTag(final long value) throws IOException {
+    writeFixed64NoTag(value);
   }
 
   /** Write a {@code float} field to the stream. */
-  public void writeFloatNoTag(final float value) throws IOException {
-    writeRawLittleEndian32(Float.floatToRawIntBits(value));
+  public final void writeFloatNoTag(final float value) throws IOException {
+    writeFixed32NoTag(Float.floatToRawIntBits(value));
   }
 
   /** Write a {@code double} field to the stream. */
-  public void writeDoubleNoTag(final double value) throws IOException {
-    writeRawLittleEndian64(Double.doubleToRawLongBits(value));
+  public final void writeDoubleNoTag(final double value) throws IOException {
+    writeFixed64NoTag(Double.doubleToRawLongBits(value));
   }
 
   /** Write a {@code bool} field to the stream. */
-  public void writeBoolNoTag(final boolean value) throws IOException {
-    writeRawByte(value ? 1 : 0);
+  public final void writeBoolNoTag(final boolean value) throws IOException {
+    write((byte) (value ? 1 : 0));
   }
 
   /**
    * Write an enum field to the stream. The provided value is the numeric
    * value used to represent the enum value on the wire (not the enum ordinal value).
    */
-  public void writeEnumNoTag(final int value) throws IOException {
+  public final void writeEnumNoTag(final int value) throws IOException {
     writeInt32NoTag(value);
   }
 
   /** Write a {@code string} field to the stream. */
   // TODO(dweis): Document behavior on ill-formed UTF-16 input.
-  public void writeStringNoTag(final String value) throws IOException {
-    try {
-      efficientWriteStringNoTag(value);
-    } catch (UnpairedSurrogateException e) {
-      logger.log(Level.WARNING,
-          "Converting ill-formed UTF-16. Your Protocol Buffer will not round trip correctly!", e);
-      inefficientWriteStringNoTag(value);
-    }
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeStringNoTag(String value) throws IOException;
 
   /** Write a {@code bytes} field to the stream. */
-  public void writeBytesNoTag(final ByteString value) throws IOException {
-    writeRawVarint32(value.size());
-    writeRawBytes(value);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeBytesNoTag(final ByteString value) throws IOException;
 
   /** Write a {@code bytes} field to the stream. */
-  public void writeByteArrayNoTag(final byte[] value) throws IOException {
-    writeRawVarint32(value.length);
-    writeRawBytes(value);
+  public final void writeByteArrayNoTag(final byte[] value) throws IOException {
+    writeByteArrayNoTag(value, 0, value.length);
   }
 
   /** Write an embedded message field to the stream. */
-  public void writeMessageNoTag(final MessageLite value) throws IOException {
-    writeRawVarint32(value.getSerializedSize());
-    value.writeTo(this);
-  }
+  // Abstract to avoid overhead of additional virtual method calls.
+  public abstract void writeMessageNoTag(final MessageLite value) throws IOException;
+
+  //=================================================================
+
+  @ExperimentalApi
+  @Override
+  public abstract void write(byte value) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void write(byte[] value, int offset, int length) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void writeLazy(byte[] value, int offset, int length) throws IOException;
+
+  @Override
+  public abstract void write(ByteBuffer value) throws IOException;
+
+  @ExperimentalApi
+  @Override
+  public abstract void writeLazy(ByteBuffer value) throws IOException;
 
   // =================================================================
   // =================================================================
@@ -727,7 +661,7 @@ public final class CodedOutputStream {
 
   /** Compute the number of bytes that would be needed to encode a tag. */
   public static int computeTagSize(final int fieldNumber) {
-    return computeRawVarint32Size(WireFormat.makeTag(fieldNumber, 0));
+    return computeUInt32SizeNoTag(WireFormat.makeTag(fieldNumber, 0));
   }
 
   /**
@@ -736,10 +670,10 @@ public final class CodedOutputStream {
    */
   public static int computeInt32SizeNoTag(final int value) {
     if (value >= 0) {
-      return computeRawVarint32Size(value);
+      return computeUInt32SizeNoTag(value);
     } else {
       // Must sign-extend.
-      return 10;
+      return MAX_VARINT_SIZE;
     }
   }
 
@@ -748,7 +682,19 @@ public final class CodedOutputStream {
    * {@code uint32} field.
    */
   public static int computeUInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(value);
+    if ((value & (~0 <<  7)) == 0) {
+      return 1;
+    }
+    if ((value & (~0 << 14)) == 0) {
+      return 2;
+    }
+    if ((value & (~0 << 21)) == 0) {
+      return 3;
+    }
+    if ((value & (~0 << 28)) == 0) {
+      return 4;
+    }
+    return 5;
   }
 
   /**
@@ -756,7 +702,7 @@ public final class CodedOutputStream {
    * {@code sint32} field.
    */
   public static int computeSInt32SizeNoTag(final int value) {
-    return computeRawVarint32Size(encodeZigZag32(value));
+    return computeUInt32SizeNoTag(encodeZigZag32(value));
   }
 
   /**
@@ -764,7 +710,7 @@ public final class CodedOutputStream {
    * {@code fixed32} field.
    */
   public static int computeFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -772,7 +718,7 @@ public final class CodedOutputStream {
    * {@code sfixed32} field.
    */
   public static int computeSFixed32SizeNoTag(@SuppressWarnings("unused") final int unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -780,15 +726,33 @@ public final class CodedOutputStream {
    * {@code int64} field, including tag.
    */
   public static int computeInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(value);
+    return computeUInt64SizeNoTag(value);
   }
 
   /**
    * Compute the number of bytes that would be needed to encode a
    * {@code uint64} field, including tag.
    */
-  public static int computeUInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(value);
+  public static int computeUInt64SizeNoTag(long value) {
+    // handle two popular special cases up front ...
+    if ((value & (~0L << 7)) == 0L) {
+      return 1;
+    }
+    if (value < 0L) {
+      return 10;
+    }
+    // ... leaving us with 8 remaining, which we can divide and conquer
+    int n = 2;
+    if ((value & (~0L << 35)) != 0L) {
+      n += 4; value >>>= 28;
+    }
+    if ((value & (~0L << 21)) != 0L) {
+      n += 2; value >>>= 14;
+    }
+    if ((value & (~0L << 14)) != 0L) {
+      n += 1;
+    }
+    return n;
   }
 
   /**
@@ -796,7 +760,7 @@ public final class CodedOutputStream {
    * {@code sint64} field.
    */
   public static int computeSInt64SizeNoTag(final long value) {
-    return computeRawVarint64Size(encodeZigZag64(value));
+    return computeUInt64SizeNoTag(encodeZigZag64(value));
   }
 
   /**
@@ -804,7 +768,7 @@ public final class CodedOutputStream {
    * {@code fixed64} field.
    */
   public static int computeFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -812,7 +776,7 @@ public final class CodedOutputStream {
    * {@code sfixed64} field.
    */
   public static int computeSFixed64SizeNoTag(@SuppressWarnings("unused") final long unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -820,7 +784,7 @@ public final class CodedOutputStream {
    * {@code float} field, including tag.
    */
   public static int computeFloatSizeNoTag(@SuppressWarnings("unused") final float unused) {
-    return LITTLE_ENDIAN_32_SIZE;
+    return FIXED_32_SIZE;
   }
 
   /**
@@ -828,7 +792,7 @@ public final class CodedOutputStream {
    * {@code double} field, including tag.
    */
   public static int computeDoubleSizeNoTag(@SuppressWarnings("unused") final double unused) {
-    return LITTLE_ENDIAN_64_SIZE;
+    return FIXED_64_SIZE;
   }
 
   /**
@@ -862,7 +826,7 @@ public final class CodedOutputStream {
       length = bytes.length;
     }
 
-    return computeRawVarint32Size(length) + length;
+    return computeLengthDelimitedFieldSize(length);
   }
 
   /**
@@ -870,8 +834,7 @@ public final class CodedOutputStream {
    * message stored in lazy field.
    */
   public static int computeLazyFieldSizeNoTag(final LazyFieldLite value) {
-    final int size = value.getSerializedSize();
-    return computeRawVarint32Size(size) + size;
+    return computeLengthDelimitedFieldSize(value.getSerializedSize());
   }
 
   /**
@@ -879,7 +842,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeBytesSizeNoTag(final ByteString value) {
-    return computeRawVarint32Size(value.size()) + value.size();
+    return computeLengthDelimitedFieldSize(value.size());
   }
 
   /**
@@ -887,7 +850,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeByteArraySizeNoTag(final byte[] value) {
-    return computeRawVarint32Size(value.length) + value.length;
+    return computeLengthDelimitedFieldSize(value.length);
   }
 
   /**
@@ -895,7 +858,7 @@ public final class CodedOutputStream {
    * {@code bytes} field.
    */
   public static int computeByteBufferSizeNoTag(final ByteBuffer value) {
-    return computeRawVarint32Size(value.capacity()) + value.capacity();
+    return computeLengthDelimitedFieldSize(value.capacity());
   }
 
   /**
@@ -903,8 +866,11 @@ public final class CodedOutputStream {
    * message field.
    */
   public static int computeMessageSizeNoTag(final MessageLite value) {
-    final int size = value.getSerializedSize();
-    return computeRawVarint32Size(size) + size;
+    return computeLengthDelimitedFieldSize(value.getSerializedSize());
+  }
+
+  private static int computeLengthDelimitedFieldSize(int fieldLength) {
+    return computeUInt32SizeNoTag(fieldLength) + fieldLength;
   }
 
   /**
@@ -943,25 +909,13 @@ public final class CodedOutputStream {
    * Flushes the stream and forces any buffered bytes to be written.  This
    * does not flush the underlying OutputStream.
    */
-  public void flush() throws IOException {
-    if (output != null) {
-      refreshBuffer();
-    }
-  }
+  public abstract void flush() throws IOException;
 
   /**
    * If writing to a flat array, return the space left in the array.
    * Otherwise, throws {@code UnsupportedOperationException}.
    */
-  public int spaceLeft() {
-    if (output == null) {
-      return limit - position;
-    } else {
-      throw new UnsupportedOperationException(
-          "spaceLeft() can only be called on CodedOutputStreams that are "
-              + "writing to a flat array.");
-    }
-  }
+  public abstract int spaceLeft();
 
   /**
    * Verifies that {@link #spaceLeft()} returns zero.  It's common to create
@@ -970,7 +924,7 @@ public final class CodedOutputStream {
    * after writing verifies that the message was actually as big as expected,
    * which can help catch bugs.
    */
-  public void checkNoSpaceLeft() {
+  public final void checkNoSpaceLeft() {
     if (spaceLeft() != 0) {
       throw new IllegalStateException("Did not write as much data as expected.");
     }
@@ -1001,183 +955,31 @@ public final class CodedOutputStream {
    * returned value is not guaranteed to be accurate if exceptions have been
    * found in the middle of writing.
    */
-  public int getTotalBytesWritten() {
-    return totalBytesWritten;
-  }
+  public abstract int getTotalBytesWritten();
 
   // =================================================================
 
-  /**
-   * Internal helper that writes the current buffer to the output. The
-   * buffer position is reset to its initial value when this returns.
-   */
-  private void refreshBuffer() throws IOException {
-    if (output == null) {
-      // We're writing to a single buffer.
-      throw new OutOfSpaceException();
-    }
+  /** Write a {@code bytes} field to the stream. Visible for testing. */
+  abstract void writeByteArrayNoTag(final byte[] value, final int offset, final int length)
+      throws IOException;
 
-    // Since we have an output stream, this is our buffer
-    // and buffer offset == 0
-    output.write(buffer, 0, position);
-    position = 0;
-  }
+  final void inefficientWriteStringNoTag(String value, UnpairedSurrogateException cause)
+      throws IOException {
+    logger.log(Level.WARNING,
+        "Converting ill-formed UTF-16. Your Protocol Buffer will not round trip correctly!", cause);
 
-  /** Write a {@code string} field to the stream. */
-  private void inefficientWriteStringNoTag(final String value) throws IOException {
     // Unfortunately there does not appear to be any way to tell Java to encode
     // UTF-8 directly into our buffer, so we have to let it create its own byte
     // array and then copy.
     // TODO(dweis): Consider using nio Charset methods instead.
     final byte[] bytes = value.getBytes(Internal.UTF_8);
-    writeRawVarint32(bytes.length);
-    writeRawBytes(bytes);
-  }
-
-  /**
-   * Write a {@code string} field to the stream efficiently. If the {@code string} is malformed,
-   * this method rolls back its changes and throws an {@link UnpairedSurrogateException} with the
-   * intent that the caller will catch and retry with {@link #inefficientWriteStringNoTag(String)}.
-   *
-   * @param value the string to write to the stream
-   *
-   * @throws UnpairedSurrogateException when {@code value} is ill-formed UTF-16.
-   */
-  private void efficientWriteStringNoTag(final String value) throws IOException {
-    // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
-    // and at most 3 times of it. We take advantage of this in both branches below.
-    final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
-    final int maxLengthVarIntSize = computeRawVarint32Size(maxLength);
-
-    // If we are streaming and the potential length is too big to fit in our buffer, we take the
-    // slower path. Otherwise, we're good to try the fast path.
-    if (output != null && maxLengthVarIntSize + maxLength > limit - position) {
-      // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
-      // does the same internally and then does *another copy* to return a byte[] of exactly the
-      // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
-      // UTF-8 encoded bytes.
-      final byte[] encodedBytes = new byte[maxLength];
-      int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
-      writeRawVarint32(actualLength);
-      writeRawBytes(encodedBytes, 0, actualLength);
-    } else {
-      // Optimize for the case where we know this length results in a constant varint length as this
-      // saves a pass for measuring the length of the string.
-      final int minLengthVarIntSize = computeRawVarint32Size(value.length());
-      int oldPosition = position;
-      final int length;
-      try {
-        if (minLengthVarIntSize == maxLengthVarIntSize) {
-          position = oldPosition + minLengthVarIntSize;
-          int newPosition = Utf8.encode(value, buffer, position, limit - position);
-          // Since this class is stateful and tracks the position, we rewind and store the state,
-          // prepend the length, then reset it back to the end of the string.
-          position = oldPosition;
-          length = newPosition - oldPosition - minLengthVarIntSize;
-          writeRawVarint32(length);
-          position = newPosition;
-        } else {
-          length = Utf8.encodedLength(value);
-          writeRawVarint32(length);
-          position = Utf8.encode(value, buffer, position, limit - position);
-        }
-      } catch (UnpairedSurrogateException e) {
-        // Be extra careful and restore the original position for retrying the write with the less
-        // efficient path.
-        position = oldPosition;
-        throw e;
-      } catch (ArrayIndexOutOfBoundsException e) {
-        throw new OutOfSpaceException(e);
-      }
-      totalBytesWritten += length;
-    }
-  }
-
-  /** Write a ByteBuffer that isn't backed by an array. */
-  private void writeRawBytesInternal(final ByteBuffer value) throws IOException {
-    int length = value.remaining();
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      value.get(buffer, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      value.get(buffer, position, bytesWritten);
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      while (length > limit) {
-        // Copy data into the buffer before writing it to OutputStream.
-        // TODO(xiaofeng): Introduce ZeroCopyOutputStream to avoid this copy.
-        value.get(buffer, 0, limit);
-        output.write(buffer, 0, limit);
-        length -= limit;
-        totalBytesWritten += limit;
-      }
-      value.get(buffer, 0, length);
-      position = length;
-      totalBytesWritten += length;
-    }
-  }
-
-  /** Write a {@code bytes} field to the stream. Visible for testing. */
-  void writeByteArrayNoTag(final byte[] value, final int offset, final int length)
-      throws IOException {
-    writeRawVarint32(length);
-    writeRawBytes(value, offset, length);
-  }
-
-  /**
-   * Write a {@code bytes} field to the stream.  This method will write all
-   * content of the ByteBuffer regardless of the current position and limit
-   * (i.e., the number of bytes to be written is value.capacity(), not
-   * value.remaining()). Furthermore, this method doesn't alter the state of
-   * the passed-in ByteBuffer. Its position, limit, mark, etc. will remain
-   * unchanged. If you only want to write the remaining bytes of a ByteBuffer,
-   * you can call {@code writeByteBufferNoTag(byteBuffer.slice())}.
-   */
-  private void writeByteBufferNoTag(final ByteBuffer value) throws IOException {
-    writeRawVarint32(value.capacity());
-    writeRawBytes(value);
-  }
-
-  /** Write part of a byte string. */
-  private void writeRawBytes(final ByteString value, int offset, int length) throws IOException {
-    if (limit - position >= length) {
-      // We have room in the current buffer.
-      value.copyTo(buffer, offset, position, length);
-      position += length;
-      totalBytesWritten += length;
-    } else {
-      // Write extends past current buffer.  Fill the rest of this buffer and
-      // flush.
-      final int bytesWritten = limit - position;
-      value.copyTo(buffer, offset, position, bytesWritten);
-      offset += bytesWritten;
-      length -= bytesWritten;
-      position = limit;
-      totalBytesWritten += bytesWritten;
-      refreshBuffer();
-
-      // Now deal with the rest.
-      // Since we have an output stream, this is our buffer
-      // and buffer offset == 0
-      if (length <= limit) {
-        // Fits in new buffer.
-        value.copyTo(buffer, offset, 0, length);
-        position = length;
-      } else {
-        value.writeTo(output, offset, length);
-      }
-      totalBytesWritten += length;
+    try {
+      writeUInt32NoTag(bytes.length);
+      writeLazy(bytes, 0, bytes.length);
+    } catch (IndexOutOfBoundsException e) {
+      throw new OutOfSpaceException(e);
+    } catch (OutOfSpaceException e) {
+      throw e;
     }
   }
 
@@ -1189,7 +991,7 @@ public final class CodedOutputStream {
    * @deprecated groups are deprecated.
    */
   @Deprecated
-  public void writeGroup(final int fieldNumber, final MessageLite value) throws IOException {
+  public final void writeGroup(final int fieldNumber, final MessageLite value) throws IOException {
     writeTag(fieldNumber, WireFormat.WIRETYPE_START_GROUP);
     writeGroupNoTag(value);
     writeTag(fieldNumber, WireFormat.WIRETYPE_END_GROUP);
@@ -1201,7 +1003,7 @@ public final class CodedOutputStream {
    * @deprecated groups are deprecated.
    */
   @Deprecated
-  public void writeGroupNoTag(final MessageLite value) throws IOException {
+  public final void writeGroupNoTag(final MessageLite value) throws IOException {
     value.writeTo(this);
   }
 
@@ -1232,16 +1034,8 @@ public final class CodedOutputStream {
    * @deprecated use {@link #writeUInt32NoTag} instead.
    */
   @Deprecated
-  public void writeRawVarint32(int value) throws IOException {
-    while (true) {
-      if ((value & ~0x7F) == 0) {
-        writeRawByte(value);
-        return;
-      } else {
-        writeRawByte((value & 0x7F) | 0x80);
-        value >>>= 7;
-      }
-    }
+  public final void writeRawVarint32(int value) throws IOException {
+    writeUInt32NoTag(value);
   }
 
   /**
@@ -1250,16 +1044,8 @@ public final class CodedOutputStream {
    * @deprecated use {@link #writeUInt64NoTag} instead.
    */
   @Deprecated
-  public void writeRawVarint64(long value) throws IOException {
-    while (true) {
-      if ((value & ~0x7FL) == 0) {
-        writeRawByte((int) value);
-        return;
-      } else {
-        writeRawByte(((int) value & 0x7F) | 0x80);
-        value >>>= 7;
-      }
-    }
+  public final void writeRawVarint64(long value) throws IOException {
+    writeUInt64NoTag(value);
   }
 
   /**
@@ -1271,19 +1057,7 @@ public final class CodedOutputStream {
    */
   @Deprecated
   public static int computeRawVarint32Size(final int value) {
-    if ((value & (~0 << 7)) == 0) {
-      return 1;
-    }
-    if ((value & (~0 << 14)) == 0) {
-      return 2;
-    }
-    if ((value & (~0 << 21)) == 0) {
-      return 3;
-    }
-    if ((value & (~0 << 28)) == 0) {
-      return 4;
-    }
-    return 5;
+    return computeUInt32SizeNoTag(value);
   }
 
   /**
@@ -1293,27 +1067,7 @@ public final class CodedOutputStream {
    */
   @Deprecated
   public static int computeRawVarint64Size(long value) {
-    // handle two popular special cases up front ...
-    if ((value & (~0L << 7)) == 0L) {
-      return 1;
-    }
-    if (value < 0L) {
-      return 10;
-    }
-    // ... leaving us with 8 remaining, which we can divide and conquer
-    int n = 2;
-    if ((value & (~0L << 35)) != 0L) {
-      n += 4;
-      value >>>= 28;
-    }
-    if ((value & (~0L << 21)) != 0L) {
-      n += 2;
-      value >>>= 14;
-    }
-    if ((value & (~0L << 14)) != 0L) {
-      n += 1;
-    }
-    return n;
+    return computeUInt64SizeNoTag(value);
   }
 
   /**
@@ -1322,11 +1076,8 @@ public final class CodedOutputStream {
    * @deprecated Use {@link #writeFixed32NoTag} instead.
    */
   @Deprecated
-  public void writeRawLittleEndian32(final int value) throws IOException {
-    writeRawByte((value) & 0xFF);
-    writeRawByte((value >> 8) & 0xFF);
-    writeRawByte((value >> 16) & 0xFF);
-    writeRawByte((value >> 24) & 0xFF);
+  public final void writeRawLittleEndian32(final int value) throws IOException {
+    writeFixed32NoTag(value);
   }
 
   /**
@@ -1335,14 +1086,1579 @@ public final class CodedOutputStream {
    * @deprecated Use {@link #writeFixed64NoTag} instead.
    */
   @Deprecated
-  public void writeRawLittleEndian64(final long value) throws IOException {
-    writeRawByte((int) (value) & 0xFF);
-    writeRawByte((int) (value >> 8) & 0xFF);
-    writeRawByte((int) (value >> 16) & 0xFF);
-    writeRawByte((int) (value >> 24) & 0xFF);
-    writeRawByte((int) (value >> 32) & 0xFF);
-    writeRawByte((int) (value >> 40) & 0xFF);
-    writeRawByte((int) (value >> 48) & 0xFF);
-    writeRawByte((int) (value >> 56) & 0xFF);
+  public final void writeRawLittleEndian64(final long value) throws IOException {
+    writeFixed64NoTag(value);
+  }
+
+  // =================================================================
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a byte array.
+   */
+  private static class ArrayEncoder extends CodedOutputStream {
+    private final byte[] buffer;
+    private final int offset;
+    private final int limit;
+    private int position;
+
+    ArrayEncoder(byte[] buffer, int offset, int length) {
+      if (buffer == null) {
+        throw new NullPointerException("buffer");
+      }
+      if ((offset | length | (buffer.length - (offset + length))) < 0) {
+        throw new IllegalArgumentException(String.format(
+            "Array range is invalid. Buffer.length=%d, offset=%d, length=%d",
+            buffer.length, offset, length));
+      }
+      this.buffer = buffer;
+      this.offset = offset;
+      position = offset;
+      limit = offset + length;
+    }
+
+    @Override
+    public final void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public final void writeInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeInt32NoTag(value);
+    }
+
+    @Override
+    public final void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt32NoTag(value);
+    }
+
+    @Override
+    public final void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      writeFixed32NoTag(value);
+    }
+
+    @Override
+    public final void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt64NoTag(value);
+    }
+
+    @Override
+    public final void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      writeFixed64NoTag(value);
+    }
+
+    @Override
+    public final void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      write((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public final void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public final void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public final void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public final void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public final void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public final void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public final void writeByteArrayNoTag(final byte[] value, int offset, int length)
+        throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public final void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public final void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public final void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public final void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public final void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public final void write(byte value) throws IOException {
+      try {
+        buffer[position++] = value;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(new IndexOutOfBoundsException(
+            String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public final void writeUInt32NoTag(int value) throws IOException {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS && spaceLeft() >= MAX_VARINT_SIZE) {
+        long pos = ARRAY_BASE_OFFSET + position;
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            position++;
+            return;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) ((value & 0x7F) | 0x80));
+            position++;
+            value >>>= 7;
+          }
+        }
+      } else {
+        try {
+          while (true) {
+            if ((value & ~0x7F) == 0) {
+              buffer[position++] = (byte) value;
+              return;
+            } else {
+              buffer[position++] = (byte) ((value & 0x7F) | 0x80);
+              value >>>= 7;
+            }
+          }
+        } catch (IndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(
+              new IndexOutOfBoundsException(
+                  String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+        }
+      }
+    }
+
+    @Override
+    public final void writeFixed32NoTag(int value) throws IOException {
+      try {
+        buffer[position++] = (byte) (value & 0xFF);
+        buffer[position++] = (byte) ((value >> 8) & 0xFF);
+        buffer[position++] = (byte) ((value >> 16) & 0xFF);
+        buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void writeUInt64NoTag(long value) throws IOException {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS && spaceLeft() >= MAX_VARINT_SIZE) {
+        long pos = ARRAY_BASE_OFFSET + position;
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            position++;
+            return;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) (((int) value & 0x7F) | 0x80));
+            position++;
+            value >>>= 7;
+          }
+        }
+      } else {
+        try {
+          while (true) {
+            if ((value & ~0x7FL) == 0) {
+              buffer[position++] = (byte) value;
+              return;
+            } else {
+              buffer[position++] = (byte) (((int) value & 0x7F) | 0x80);
+              value >>>= 7;
+            }
+          }
+        } catch (IndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(
+              new IndexOutOfBoundsException(
+                  String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+        }
+      }
+    }
+
+    @Override
+    public final void writeFixed64NoTag(long value) throws IOException {
+      try {
+        buffer[position++] = (byte) ((int) (value) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 8) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 16) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 24) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 32) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 40) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 48) & 0xFF);
+        buffer[position++] = (byte) ((int) (value >> 56) & 0xFF);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, 1)));
+      }
+    }
+
+    @Override
+    public final void write(byte[] value, int offset, int length) throws IOException {
+      try {
+        System.arraycopy(value, offset, buffer, position, length);
+        position += length;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, length)));
+      }
+    }
+
+    @Override
+    public final void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public final void write(ByteBuffer value) throws IOException {
+      final int length = value.remaining();
+      try {
+        value.get(buffer, position, length);
+        position += length;
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(
+            new IndexOutOfBoundsException(
+                String.format("Pos: %d, limit: %d, len: %d", position, limit, length)));
+      }
+    }
+
+    @Override
+    public final void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    @Override
+    public final void writeStringNoTag(String value) throws IOException {
+      final int oldPosition = position;
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          position = oldPosition + minLengthVarIntSize;
+          int newPosition = Utf8.encode(value, buffer, position, spaceLeft());
+          // Since this class is stateful and tracks the position, we rewind and store the state,
+          // prepend the length, then reset it back to the end of the string.
+          position = oldPosition;
+          int length = newPosition - oldPosition - minLengthVarIntSize;
+          writeUInt32NoTag(length);
+          position = newPosition;
+        } else {
+          int length = Utf8.encodedLength(value);
+          writeUInt32NoTag(length);
+          position = Utf8.encode(value, buffer, position, spaceLeft());
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change - we fall back to inefficient path.
+        position = oldPosition;
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() {
+      // Do nothing.
+    }
+
+    @Override
+    public final int spaceLeft() {
+      return limit - position;
+    }
+
+    @Override
+    public final int getTotalBytesWritten() {
+      return position - offset;
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a heap {@link ByteBuffer}. Writes are
+   * done directly to the underlying array. The buffer position is only updated after a flush.
+   */
+  private static final class NioHeapEncoder extends ArrayEncoder {
+    private final ByteBuffer byteBuffer;
+    private int initialPosition;
+
+    NioHeapEncoder(ByteBuffer byteBuffer) {
+      super(byteBuffer.array(), byteBuffer.arrayOffset() + byteBuffer.position(),
+          byteBuffer.remaining());
+      this.byteBuffer = byteBuffer;
+      this.initialPosition = byteBuffer.position();
+    }
+
+    @Override
+    public void flush() {
+      // Update the position on the buffer.
+      byteBuffer.position(initialPosition + getTotalBytesWritten());
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that writes directly to a {@link ByteBuffer}.
+   */
+  private static final class NioEncoder extends CodedOutputStream {
+    private final ByteBuffer originalBuffer;
+    private final ByteBuffer buffer;
+    private final int initialPosition;
+
+    NioEncoder(ByteBuffer buffer) {
+      this.originalBuffer = buffer;
+      this.buffer = buffer.duplicate().order(ByteOrder.LITTLE_ENDIAN);
+      initialPosition = buffer.position();
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      writeFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      writeUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      writeFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      write((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      try {
+        buffer.put(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      try {
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            buffer.put((byte) value);
+            return;
+          } else {
+            buffer.put((byte) ((value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeFixed32NoTag(int value) throws IOException {
+      try {
+        buffer.putInt(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      try {
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            buffer.put((byte) value);
+            return;
+          } else {
+            buffer.put((byte) (((int) value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeFixed64NoTag(long value) throws IOException {
+      try {
+        buffer.putLong(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length) throws IOException {
+      try {
+        buffer.put(value, offset, length);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      try {
+        buffer.put(value);
+      } catch (BufferOverflowException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      final int startPos = buffer.position();
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxEncodedSize = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxEncodedSize);
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          // Save the current position and increment past the length field. We'll come back
+          // and write the length field after the encoding is complete.
+          final int startOfBytes = buffer.position() + minLengthVarIntSize;
+          buffer.position(startOfBytes);
+
+          // Encode the string.
+          encode(value);
+
+          // Now go back to the beginning and write the length.
+          int endOfBytes = buffer.position();
+          buffer.position(startPos);
+          writeUInt32NoTag(endOfBytes - startOfBytes);
+
+          // Reposition the buffer past the written data.
+          buffer.position(endOfBytes);
+        } else {
+          final int length = Utf8.encodedLength(value);
+          writeUInt32NoTag(length);
+          encode(value);
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change and convert to an IOException.
+        buffer.position(startPos);
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IllegalArgumentException e) {
+        // Thrown by buffer.position() if out of range.
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() {
+      // Update the position of the original buffer.
+      originalBuffer.position(buffer.position());
+    }
+
+    @Override
+    public int spaceLeft() {
+      return buffer.remaining();
+    }
+
+    @Override
+    public int getTotalBytesWritten() {
+      return buffer.position() - initialPosition;
+    }
+
+    private void encode(String value) throws IOException {
+      try {
+        Utf8.encodeUtf8(value, buffer);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+  }
+
+  /**
+   * Abstract base class for buffered encoders.
+   */
+  private abstract static class AbstractBufferedEncoder extends CodedOutputStream {
+    final byte[] buffer;
+    final int limit;
+    int position;
+    int totalBytesWritten;
+
+    AbstractBufferedEncoder(int bufferSize) {
+      if (bufferSize < 0) {
+        throw new IllegalArgumentException("bufferSize must be >= 0");
+      }
+      // As an optimization, we require that the buffer be able to store at least 2
+      // varints so that we can buffer any integer write (tag + value). This reduces the
+      // number of range checks for a single write to 1 (i.e. if there is not enough space
+      // to buffer the tag+value, flush and then buffer it).
+      this.buffer = new byte[max(bufferSize, MAX_VARINT_SIZE * 2)];
+      this.limit = buffer.length;
+    }
+
+    @Override
+    public final int spaceLeft() {
+      throw new UnsupportedOperationException(
+          "spaceLeft() can only be called on CodedOutputStreams that are "
+              + "writing to a flat array or ByteBuffer.");
+    }
+
+    @Override
+    public final int getTotalBytesWritten() {
+      return totalBytesWritten;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void buffer(byte value) {
+      buffer[position++] = value;
+      totalBytesWritten++;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferTag(final int fieldNumber, final int wireType) {
+      bufferUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferInt32NoTag(final int value) {
+      if (value >= 0) {
+        bufferUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        bufferUInt64NoTag(value);
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferUInt32NoTag(int value) {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS) {
+        final long originalPos = ARRAY_BASE_OFFSET + position;
+        long pos = originalPos;
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            break;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) ((value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+        int delta = (int) (pos - originalPos);
+        position += delta;
+        totalBytesWritten += delta;
+      } else {
+        while (true) {
+          if ((value & ~0x7F) == 0) {
+            buffer[position++] = (byte) value;
+            totalBytesWritten++;
+            return;
+          } else {
+            buffer[position++] = (byte) ((value & 0x7F) | 0x80);
+            totalBytesWritten++;
+            value >>>= 7;
+          }
+        }
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferUInt64NoTag(long value) {
+      if (HAS_UNSAFE_ARRAY_OPERATIONS) {
+        final long originalPos = ARRAY_BASE_OFFSET + position;
+        long pos = originalPos;
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            UNSAFE.putByte(buffer, pos++, (byte) value);
+            break;
+          } else {
+            UNSAFE.putByte(buffer, pos++, (byte) (((int) value & 0x7F) | 0x80));
+            value >>>= 7;
+          }
+        }
+        int delta = (int) (pos - originalPos);
+        position += delta;
+        totalBytesWritten += delta;
+      } else {
+        while (true) {
+          if ((value & ~0x7FL) == 0) {
+            buffer[position++] = (byte) value;
+            totalBytesWritten++;
+            return;
+          } else {
+            buffer[position++] = (byte) (((int) value & 0x7F) | 0x80);
+            totalBytesWritten++;
+            value >>>= 7;
+          }
+        }
+      }
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferFixed32NoTag(int value) {
+      buffer[position++] = (byte) (value & 0xFF);
+      buffer[position++] = (byte) ((value >> 8) & 0xFF);
+      buffer[position++] = (byte) ((value >> 16) & 0xFF);
+      buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      totalBytesWritten += FIXED_32_SIZE;
+    }
+
+    /**
+     * This method does not perform bounds checking on the array. Checking array bounds is the
+     * responsibility of the caller.
+     */
+    final void bufferFixed64NoTag(long value) {
+      buffer[position++] = (byte) (value & 0xFF);
+      buffer[position++] = (byte) ((value >> 8) & 0xFF);
+      buffer[position++] = (byte) ((value >> 16) & 0xFF);
+      buffer[position++] = (byte) ((value >> 24) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 32) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 40) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 48) & 0xFF);
+      buffer[position++] = (byte) ((int) (value >> 56) & 0xFF);
+      totalBytesWritten += FIXED_64_SIZE;
+    }
+  }
+
+  /**
+   * A {@link CodedOutputStream} that decorates a {@link ByteOutput}. It internal buffer only to
+   * support string encoding operations. All other writes are just passed through to the
+   * {@link ByteOutput}.
+   */
+  private static final class ByteOutputEncoder extends AbstractBufferedEncoder {
+    private final ByteOutput out;
+
+    ByteOutputEncoder(ByteOutput out, int bufferSize) {
+      super(bufferSize);
+      if (out == null) {
+        throw new NullPointerException("out");
+      }
+      this.out = out;
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_32_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_64_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + 1);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      buffer((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      if (position == limit) {
+        doFlush();
+      }
+
+      buffer(value);
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32NoTag(final int value) throws IOException {
+      flushIfNotAvailable(FIXED_32_SIZE);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64NoTag(final long value) throws IOException {
+      flushIfNotAvailable(FIXED_64_SIZE);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+      // and at most 3 times of it. We take advantage of this in both branches below.
+      final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+      final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+
+      // If we are streaming and the potential length is too big to fit in our buffer, we take the
+      // slower path.
+      if (maxLengthVarIntSize + maxLength > limit) {
+        // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
+        // does the same internally and then does *another copy* to return a byte[] of exactly the
+        // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
+        // UTF-8 encoded bytes.
+        final byte[] encodedBytes = new byte[maxLength];
+        int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
+        writeUInt32NoTag(actualLength);
+        writeLazy(encodedBytes, 0, actualLength);
+        return;
+      }
+
+      // Fast path: we have enough space available in our buffer for the string...
+      if (maxLengthVarIntSize + maxLength > limit - position) {
+        // Flush to free up space.
+        doFlush();
+      }
+
+      final int oldPosition = position;
+      try {
+        // Optimize for the case where we know this length results in a constant varint length as
+        // this saves a pass for measuring the length of the string.
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+
+        if (minLengthVarIntSize == maxLengthVarIntSize) {
+          position = oldPosition + minLengthVarIntSize;
+          int newPosition = Utf8.encode(value, buffer, position, limit - position);
+          // Since this class is stateful and tracks the position, we rewind and store the state,
+          // prepend the length, then reset it back to the end of the string.
+          position = oldPosition;
+          int length = newPosition - oldPosition - minLengthVarIntSize;
+          bufferUInt32NoTag(length);
+          position = newPosition;
+          totalBytesWritten += length;
+        } else {
+          int length = Utf8.encodedLength(value);
+          bufferUInt32NoTag(length);
+          position = Utf8.encode(value, buffer, position, length);
+          totalBytesWritten += length;
+        }
+      } catch (UnpairedSurrogateException e) {
+        // Roll back the change and convert to an IOException.
+        totalBytesWritten -= position - oldPosition;
+        position = oldPosition;
+
+        // TODO(nathanmittler): We should throw an IOException here instead.
+        inefficientWriteStringNoTag(value, e);
+      } catch (IndexOutOfBoundsException e) {
+        throw new OutOfSpaceException(e);
+      }
+    }
+
+    @Override
+    public void flush() throws IOException {
+      if (position > 0) {
+        // Flush the buffer.
+        doFlush();
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length) throws IOException {
+      flush();
+      out.write(value, offset, length);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      flush();
+      out.writeLazy(value, offset, length);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      flush();
+      int length = value.remaining();
+      out.write(value);
+      totalBytesWritten += length;
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      flush();
+      int length = value.remaining();
+      out.writeLazy(value);
+      totalBytesWritten += length;
+    }
+
+    private void flushIfNotAvailable(int requiredSize) throws IOException {
+      if (limit - position < requiredSize) {
+        doFlush();
+      }
+    }
+
+    private void doFlush() throws IOException {
+      out.write(buffer, 0, position);
+      position = 0;
+    }
+  }
+
+  /**
+   * An {@link CodedOutputStream} that decorates an {@link OutputStream}. It performs internal
+   * buffering to optimize writes to the {@link OutputStream}.
+   */
+  private static final class OutputStreamEncoder extends AbstractBufferedEncoder {
+    private final OutputStream out;
+
+    OutputStreamEncoder(OutputStream out, int bufferSize) {
+      super(bufferSize);
+      if (out == null) {
+        throw new NullPointerException("out");
+      }
+      this.out = out;
+    }
+
+    @Override
+    public void writeTag(final int fieldNumber, final int wireType) throws IOException {
+      writeUInt32NoTag(WireFormat.makeTag(fieldNumber, wireType));
+    }
+
+    @Override
+    public void writeInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferInt32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32(final int fieldNumber, final int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_32_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED32);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE * 2);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64(final int fieldNumber, final long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + FIXED_64_SIZE);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_FIXED64);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeBool(final int fieldNumber, final boolean value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE + 1);
+      bufferTag(fieldNumber, WireFormat.WIRETYPE_VARINT);
+      buffer((byte) (value ? 1 : 0));
+    }
+
+    @Override
+    public void writeString(final int fieldNumber, final String value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeStringNoTag(value);
+    }
+
+    @Override
+    public void writeBytes(final int fieldNumber, final ByteString value) throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeBytesNoTag(value);
+    }
+
+    @Override
+    public void writeByteArray(final int fieldNumber, final byte[] value) throws IOException {
+      writeByteArray(fieldNumber, value, 0, value.length);
+    }
+
+    @Override
+    public void writeByteArray(
+        final int fieldNumber, final byte[] value, final int offset, final int length)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeByteArrayNoTag(value, offset, length);
+    }
+
+    @Override
+    public void writeByteBuffer(final int fieldNumber, final ByteBuffer value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeUInt32NoTag(value.capacity());
+      writeRawBytes(value);
+    }
+
+    @Override
+    public void writeBytesNoTag(final ByteString value) throws IOException {
+      writeUInt32NoTag(value.size());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void writeByteArrayNoTag(final byte[] value, int offset, int length) throws IOException {
+      writeUInt32NoTag(length);
+      write(value, offset, length);
+    }
+
+    @Override
+    public void writeRawBytes(final ByteBuffer value) throws IOException {
+      if (value.hasArray()) {
+        write(value.array(), value.arrayOffset(), value.capacity());
+      } else {
+        ByteBuffer duplicated = value.duplicate();
+        duplicated.clear();
+        write(duplicated);
+      }
+    }
+
+    @Override
+    public void writeMessage(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(fieldNumber, WireFormat.WIRETYPE_LENGTH_DELIMITED);
+      writeMessageNoTag(value);
+    }
+
+    @Override
+    public void writeMessageSetExtension(final int fieldNumber, final MessageLite value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeMessage(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeRawMessageSetExtension(final int fieldNumber, final ByteString value)
+        throws IOException {
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_START_GROUP);
+      writeUInt32(WireFormat.MESSAGE_SET_TYPE_ID, fieldNumber);
+      writeBytes(WireFormat.MESSAGE_SET_MESSAGE, value);
+      writeTag(WireFormat.MESSAGE_SET_ITEM, WireFormat.WIRETYPE_END_GROUP);
+    }
+
+    @Override
+    public void writeMessageNoTag(final MessageLite value) throws IOException {
+      writeUInt32NoTag(value.getSerializedSize());
+      value.writeTo(this);
+    }
+
+    @Override
+    public void write(byte value) throws IOException {
+      if (position == limit) {
+        doFlush();
+      }
+
+      buffer(value);
+    }
+
+    @Override
+    public void writeInt32NoTag(int value) throws IOException {
+      if (value >= 0) {
+        writeUInt32NoTag(value);
+      } else {
+        // Must sign-extend.
+        writeUInt64NoTag(value);
+      }
+    }
+
+    @Override
+    public void writeUInt32NoTag(int value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt32NoTag(value);
+    }
+
+    @Override
+    public void writeFixed32NoTag(final int value) throws IOException {
+      flushIfNotAvailable(FIXED_32_SIZE);
+      bufferFixed32NoTag(value);
+    }
+
+    @Override
+    public void writeUInt64NoTag(long value) throws IOException {
+      flushIfNotAvailable(MAX_VARINT_SIZE);
+      bufferUInt64NoTag(value);
+    }
+
+    @Override
+    public void writeFixed64NoTag(final long value) throws IOException {
+      flushIfNotAvailable(FIXED_64_SIZE);
+      bufferFixed64NoTag(value);
+    }
+
+    @Override
+    public void writeStringNoTag(String value) throws IOException {
+      try {
+        // UTF-8 byte length of the string is at least its UTF-16 code unit length (value.length()),
+        // and at most 3 times of it. We take advantage of this in both branches below.
+        final int maxLength = value.length() * Utf8.MAX_BYTES_PER_CHAR;
+        final int maxLengthVarIntSize = computeUInt32SizeNoTag(maxLength);
+
+        // If we are streaming and the potential length is too big to fit in our buffer, we take the
+        // slower path.
+        if (maxLengthVarIntSize + maxLength > limit) {
+          // Allocate a byte[] that we know can fit the string and encode into it. String.getBytes()
+          // does the same internally and then does *another copy* to return a byte[] of exactly the
+          // right size. We can skip that copy and just writeRawBytes up to the actualLength of the
+          // UTF-8 encoded bytes.
+          final byte[] encodedBytes = new byte[maxLength];
+          int actualLength = Utf8.encode(value, encodedBytes, 0, maxLength);
+          writeUInt32NoTag(actualLength);
+          writeLazy(encodedBytes, 0, actualLength);
+          return;
+        }
+
+        // Fast path: we have enough space available in our buffer for the string...
+        if (maxLengthVarIntSize + maxLength > limit - position) {
+          // Flush to free up space.
+          doFlush();
+        }
+
+        // Optimize for the case where we know this length results in a constant varint length as
+        // this saves a pass for measuring the length of the string.
+        final int minLengthVarIntSize = computeUInt32SizeNoTag(value.length());
+        int oldPosition = position;
+        final int length;
+        try {
+          if (minLengthVarIntSize == maxLengthVarIntSize) {
+            position = oldPosition + minLengthVarIntSize;
+            int newPosition = Utf8.encode(value, buffer, position, limit - position);
+            // Since this class is stateful and tracks the position, we rewind and store the
+            // state, prepend the length, then reset it back to the end of the string.
+            position = oldPosition;
+            length = newPosition - oldPosition - minLengthVarIntSize;
+            bufferUInt32NoTag(length);
+            position = newPosition;
+          } else {
+            length = Utf8.encodedLength(value);
+            bufferUInt32NoTag(length);
+            position = Utf8.encode(value, buffer, position, length);
+          }
+          totalBytesWritten += length;
+        } catch (UnpairedSurrogateException e) {
+          // Be extra careful and restore the original position for retrying the write with the
+          // less efficient path.
+          totalBytesWritten -= position - oldPosition;
+          position = oldPosition;
+          throw e;
+        } catch (ArrayIndexOutOfBoundsException e) {
+          throw new OutOfSpaceException(e);
+        }
+      } catch (UnpairedSurrogateException e) {
+        inefficientWriteStringNoTag(value, e);
+      }
+    }
+
+    @Override
+    public void flush() throws IOException {
+      if (position > 0) {
+        // Flush the buffer.
+        doFlush();
+      }
+    }
+
+    @Override
+    public void write(byte[] value, int offset, int length)
+        throws IOException {
+      if (limit - position >= length) {
+        // We have room in the current buffer.
+        System.arraycopy(value, offset, buffer, position, length);
+        position += length;
+        totalBytesWritten += length;
+      } else {
+        // Write extends past current buffer.  Fill the rest of this buffer and
+        // flush.
+        final int bytesWritten = limit - position;
+        System.arraycopy(value, offset, buffer, position, bytesWritten);
+        offset += bytesWritten;
+        length -= bytesWritten;
+        position = limit;
+        totalBytesWritten += bytesWritten;
+        doFlush();
+
+        // Now deal with the rest.
+        // Since we have an output stream, this is our buffer
+        // and buffer offset == 0
+        if (length <= limit) {
+          // Fits in new buffer.
+          System.arraycopy(value, offset, buffer, 0, length);
+          position = length;
+        } else {
+          // Write is very big.  Let's do it all at once.
+          out.write(value, offset, length);
+        }
+        totalBytesWritten += length;
+      }
+    }
+
+    @Override
+    public void writeLazy(byte[] value, int offset, int length) throws IOException {
+      write(value, offset, length);
+    }
+
+    @Override
+    public void write(ByteBuffer value) throws IOException {
+      int length = value.remaining();
+      if (limit - position >= length) {
+        // We have room in the current buffer.
+        value.get(buffer, position, length);
+        position += length;
+        totalBytesWritten += length;
+      } else {
+        // Write extends past current buffer.  Fill the rest of this buffer and
+        // flush.
+        final int bytesWritten = limit - position;
+        value.get(buffer, position, bytesWritten);
+        length -= bytesWritten;
+        position = limit;
+        totalBytesWritten += bytesWritten;
+        doFlush();
+
+        // Now deal with the rest.
+        // Since we have an output stream, this is our buffer
+        // and buffer offset == 0
+        while (length > limit) {
+          // Copy data into the buffer before writing it to OutputStream.
+          value.get(buffer, 0, limit);
+          out.write(buffer, 0, limit);
+          length -= limit;
+          totalBytesWritten += limit;
+        }
+        value.get(buffer, 0, length);
+        position = length;
+        totalBytesWritten += length;
+      }
+    }
+
+    @Override
+    public void writeLazy(ByteBuffer value) throws IOException {
+      write(value);
+    }
+
+    private void flushIfNotAvailable(int requiredSize) throws IOException {
+      if (limit - position < requiredSize) {
+        doFlush();
+      }
+    }
+
+    private void doFlush() throws IOException {
+      out.write(buffer, 0, position);
+      position = 0;
+    }
+  }
+
+  /**
+   * Gets the {@code sun.misc.Unsafe} instance, or {@code null} if not available on this
+   * platform.
+   */
+  private static sun.misc.Unsafe getUnsafe() {
+    sun.misc.Unsafe unsafe = null;
+    try {
+      unsafe = AccessController.doPrivileged(new PrivilegedExceptionAction<sun.misc.Unsafe>() {
+        @Override
+        public sun.misc.Unsafe run() throws Exception {
+          Class<sun.misc.Unsafe> k = sun.misc.Unsafe.class;
+
+          for (Field f : k.getDeclaredFields()) {
+            f.setAccessible(true);
+            Object x = f.get(null);
+            if (k.isInstance(x)) {
+              return k.cast(x);
+            }
+          }
+          // The sun.misc.Unsafe field does not exist.
+          return null;
+        }
+      });
+    } catch (Throwable e) {
+      // Catching Throwable here due to the fact that Google AppEngine raises NoClassDefFoundError
+      // for Unsafe.
+    }
+
+    logger.log(Level.FINEST, "sun.misc.Unsafe: {}",
+        unsafe != null ? "available" : "unavailable");
+    return unsafe;
+  }
+
+  /**
+   * Indicates whether or not unsafe array operations are supported on this platform.
+   */
+  // TODO(nathanmittler): Add support for Android's MemoryBlock.
+  private static boolean supportsUnsafeArrayOperations() {
+    boolean supported = false;
+    if (UNSAFE != null) {
+      try {
+        UNSAFE.getClass().getMethod("arrayBaseOffset", Class.class);
+        UNSAFE.getClass().getMethod("putByte", Object.class, long.class, byte.class);
+        supported = true;
+      } catch (Throwable e) {
+        // Do nothing.
+      }
+    }
+    logger.log(Level.FINEST, "Unsafe array operations: {}",
+        supported ? "available" : "unavailable");
+    return supported;
+  }
+
+  /**
+   * Get the base offset for byte arrays, or {@code -1} if {@code sun.misc.Unsafe} is not
+   * available.
+   */
+  private static <T> int byteArrayBaseOffset() {
+    return HAS_UNSAFE_ARRAY_OPERATIONS ? UNSAFE.arrayBaseOffset(byte[].class) : -1;
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/Descriptors.java b/java/core/src/main/java/com/google/protobuf/Descriptors.java
index e303e138..e00ea342 100644
--- a/java/core/src/main/java/com/google/protobuf/Descriptors.java
+++ b/java/core/src/main/java/com/google/protobuf/Descriptors.java
@@ -74,16 +74,28 @@ public final class Descriptors {
    */
   public static final class FileDescriptor extends GenericDescriptor {
     /** Convert the descriptor to its protocol message representation. */
-    public FileDescriptorProto toProto() { return proto; }
+    @Override
+    public FileDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the file name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Returns this object. */
-    public FileDescriptor getFile() { return this; }
+    @Override
+    public FileDescriptor getFile() {
+      return this;
+    }
 
     /** Returns the same as getName(). */
-    public String getFullName() { return proto.getName(); }
+    @Override
+    public String getFullName() {
+      return proto.getName();
+    }
 
     /**
      * Get the proto package name.  This is the package name given by the
@@ -582,10 +594,16 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public DescriptorProto toProto() { return proto; }
+    @Override
+    public DescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name, within the proto language's
@@ -598,10 +616,16 @@ public final class Descriptors {
      * </pre>
      * {@code Baz}'s full name is "foo.bar.Baz".
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** If this is a nested type, get the outer descriptor, otherwise null. */
     public Descriptor getContainingType() { return containingType; }
@@ -875,19 +899,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public FieldDescriptorProto toProto() { return proto; }
+    @Override
+    public FieldDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the field's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Get the field's number. */
-    public int getNumber() { return proto.getNumber(); }
+    @Override
+    public int getNumber() {
+      return proto.getNumber();
+    }
 
     /**
      * Get the field's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the JSON name of this field. */
     public String getJsonName() {
@@ -901,17 +937,22 @@ public final class Descriptors {
     public JavaType getJavaType() { return type.getJavaType(); }
 
     /** For internal use only. */
+    @Override
     public WireFormat.JavaType getLiteJavaType() {
       return getLiteType().getJavaType();
     }
 
     /** Get the {@code FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the field's declared type. */
     public Type getType() { return type; }
 
     /** For internal use only. */
+    @Override
     public WireFormat.FieldType getLiteType() {
       return table[type.ordinal()];
     }
@@ -953,6 +994,7 @@ public final class Descriptors {
     }
 
     /** Is this field declared repeated? */
+    @Override
     public boolean isRepeated() {
       return proto.getLabel() == FieldDescriptorProto.Label.LABEL_REPEATED;
     }
@@ -960,6 +1002,7 @@ public final class Descriptors {
     /** Does this field have the {@code [packed = true]} option or is this field
      *  packable in proto3 and not explicitly setted to unpacked?
      */
+    @Override
     public boolean isPacked() {
       if (!isPackable()) {
         return false;
@@ -1048,6 +1091,7 @@ public final class Descriptors {
     }
 
     /** For enum fields, gets the field's type. */
+    @Override
     public EnumDescriptor getEnumType() {
       if (getJavaType() != JavaType.ENUM) {
         throw new UnsupportedOperationException(
@@ -1066,6 +1110,7 @@ public final class Descriptors {
      * @return negative, zero, or positive if {@code this} is less than,
      *         equal to, or greater than {@code other}, respectively.
      */
+    @Override
     public int compareTo(final FieldDescriptor other) {
       if (other.containingType != containingType) {
         throw new IllegalArgumentException(
@@ -1466,8 +1511,8 @@ public final class Descriptors {
      * For internal use only.  This is to satisfy the FieldDescriptorLite
      * interface.
      */
-    public MessageLite.Builder internalMergeFrom(
-        MessageLite.Builder to, MessageLite from) {
+    @Override
+    public MessageLite.Builder internalMergeFrom(MessageLite.Builder to, MessageLite from) {
       // FieldDescriptors are only used with non-lite messages so we can just
       // down-cast and call mergeFrom directly.
       return ((Message.Builder) to).mergeFrom((Message) from);
@@ -1487,19 +1532,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public EnumDescriptorProto toProto() { return proto; }
+    @Override
+    public EnumDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** If this is a nested type, get the outer descriptor, otherwise null. */
     public Descriptor getContainingType() { return containingType; }
@@ -1533,6 +1590,7 @@ public final class Descriptors {
      * @param number The value's number.
      * @return the value's descriptor, or {@code null} if not found.
      */
+    @Override
     public EnumValueDescriptor findValueByNumber(final int number) {
       return file.pool.enumValuesByNumber.get(
         new DescriptorPool.DescriptorIntPair(this, number));
@@ -1659,13 +1717,22 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public EnumValueDescriptorProto toProto() { return proto; }
+    @Override
+    public EnumValueDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the value's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /** Get the value's number. */
-    public int getNumber() { return proto.getNumber(); }
+    @Override
+    public int getNumber() {
+      return proto.getNumber();
+    }
 
     @Override
     public String toString() { return proto.getName(); }
@@ -1674,10 +1741,16 @@ public final class Descriptors {
      * Get the value's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the value's enum type. */
     public EnumDescriptor getType() { return type; }
@@ -1745,19 +1818,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public ServiceDescriptorProto toProto() { return proto; }
+    @Override
+    public ServiceDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the type's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the type's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the {@code ServiceOptions}, defined in {@code descriptor.proto}. */
     public ServiceOptions getOptions() { return proto.getOptions(); }
@@ -1835,19 +1920,31 @@ public final class Descriptors {
     public int getIndex() { return index; }
 
     /** Convert the descriptor to its protocol message representation. */
-    public MethodDescriptorProto toProto() { return proto; }
+    @Override
+    public MethodDescriptorProto toProto() {
+      return proto;
+    }
 
     /** Get the method's unqualified name. */
-    public String getName() { return proto.getName(); }
+    @Override
+    public String getName() {
+      return proto.getName();
+    }
 
     /**
      * Get the method's fully-qualified name.
      * @see Descriptors.Descriptor#getFullName()
      */
-    public String getFullName() { return fullName; }
+    @Override
+    public String getFullName() {
+      return fullName;
+    }
 
     /** Get the {@link FileDescriptor} containing this descriptor. */
-    public FileDescriptor getFile() { return file; }
+    @Override
+    public FileDescriptor getFile() {
+      return file;
+    }
 
     /** Get the method's service type. */
     public ServiceDescriptor getService() { return service; }
@@ -2248,10 +2345,22 @@ public final class Descriptors {
      * that has the same name as an existing package.
      */
     private static final class PackageDescriptor extends GenericDescriptor {
-      public Message toProto()        { return file.toProto(); }
-      public String getName()         { return name;           }
-      public String getFullName()     { return fullName;       }
-      public FileDescriptor getFile() { return file;           }
+      @Override
+      public Message toProto() {
+        return file.toProto();
+      }
+      @Override
+      public String getName() {
+        return name;
+      }
+      @Override
+      public String getFullName() {
+        return fullName;
+      }
+      @Override
+      public FileDescriptor getFile() {
+        return file;
+      }
 
       PackageDescriptor(final String name, final String fullName,
                         final FileDescriptor file) {
diff --git a/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java b/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
index bcc9d6ee..a9543b83 100644
--- a/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/DoubleArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.DoubleList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -45,8 +44,6 @@ import java.util.RandomAccess;
 final class DoubleArrayList
     extends AbstractProtobufList<Double> implements DoubleList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final DoubleArrayList EMPTY_LIST = new DoubleArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -71,32 +68,56 @@ final class DoubleArrayList
    * Constructs a new mutable {@code DoubleArrayList} with default capacity.
    */
   DoubleArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code DoubleArrayList} with the provided capacity.
-   */
-  DoubleArrayList(int capacity) {
-    array = new double[capacity];
-    size = 0;
+    this(new double[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code DoubleArrayList} containing the same elements as {@code other}.
    */
-  DoubleArrayList(List<Double> other) {
-    if (other instanceof DoubleArrayList) {
-      DoubleArrayList list = (DoubleArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new double[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private DoubleArrayList(double[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof DoubleArrayList)) {
+      return super.equals(o);
+    }
+    DoubleArrayList other = (DoubleArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final double[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      long bits = Double.doubleToLongBits(array[i]);
+      result = (31 * result) + Internal.hashLong(bits);
+    }
+    return result;
+  }
+
+  @Override
+  public DoubleList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new DoubleArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/DynamicMessage.java b/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
index 3ea1b688..859a9e8f 100644
--- a/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/DynamicMessage.java
@@ -156,18 +156,22 @@ public final class DynamicMessage extends AbstractMessage {
   // -----------------------------------------------------------------
   // Implementation of Message interface.
 
+  @Override
   public Descriptor getDescriptorForType() {
     return type;
   }
 
+  @Override
   public DynamicMessage getDefaultInstanceForType() {
     return getDefaultInstance(type);
   }
 
+  @Override
   public Map<FieldDescriptor, Object> getAllFields() {
     return fields.getAllFields();
   }
 
+  @Override
   public boolean hasOneof(OneofDescriptor oneof) {
     verifyOneofContainingType(oneof);
     FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -177,16 +181,19 @@ public final class DynamicMessage extends AbstractMessage {
     return true;
   }
 
+  @Override
   public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
     verifyOneofContainingType(oneof);
     return oneofCases[oneof.getIndex()];
   }
 
+  @Override
   public boolean hasField(FieldDescriptor field) {
     verifyContainingType(field);
     return fields.hasField(field);
   }
 
+  @Override
   public Object getField(FieldDescriptor field) {
     verifyContainingType(field);
     Object result = fields.getField(field);
@@ -202,16 +209,19 @@ public final class DynamicMessage extends AbstractMessage {
     return result;
   }
 
+  @Override
   public int getRepeatedFieldCount(FieldDescriptor field) {
     verifyContainingType(field);
     return fields.getRepeatedFieldCount(field);
   }
 
+  @Override
   public Object getRepeatedField(FieldDescriptor field, int index) {
     verifyContainingType(field);
     return fields.getRepeatedField(field, index);
   }
 
+  @Override
   public UnknownFieldSet getUnknownFields() {
     return unknownFields;
   }
@@ -264,19 +274,22 @@ public final class DynamicMessage extends AbstractMessage {
     return size;
   }
 
+  @Override
   public Builder newBuilderForType() {
     return new Builder(type);
   }
 
+  @Override
   public Builder toBuilder() {
     return newBuilderForType().mergeFrom(this);
   }
 
+  @Override
   public Parser<DynamicMessage> getParserForType() {
     return new AbstractParser<DynamicMessage>() {
+      @Override
       public DynamicMessage parsePartialFrom(
-          CodedInputStream input,
-          ExtensionRegistryLite extensionRegistry)
+          CodedInputStream input, ExtensionRegistryLite extensionRegistry)
           throws InvalidProtocolBufferException {
         Builder builder = newBuilder(type);
         try {
@@ -370,6 +383,7 @@ public final class DynamicMessage extends AbstractMessage {
       }
     }
 
+    @Override
     public DynamicMessage build() {
       if (!isInitialized()) {
         throw newUninitializedMessageException(
@@ -394,6 +408,7 @@ public final class DynamicMessage extends AbstractMessage {
       return buildPartial();
     }
 
+    @Override
     public DynamicMessage buildPartial() {
       fields.makeImmutable();
       DynamicMessage result =
@@ -411,22 +426,27 @@ public final class DynamicMessage extends AbstractMessage {
       return result;
     }
 
+    @Override
     public boolean isInitialized() {
       return DynamicMessage.isInitialized(type, fields);
     }
 
+    @Override
     public Descriptor getDescriptorForType() {
       return type;
     }
 
+    @Override
     public DynamicMessage getDefaultInstanceForType() {
       return getDefaultInstance(type);
     }
 
+    @Override
     public Map<FieldDescriptor, Object> getAllFields() {
       return fields.getAllFields();
     }
 
+    @Override
     public Builder newBuilderForField(FieldDescriptor field) {
       verifyContainingType(field);
 
@@ -438,6 +458,7 @@ public final class DynamicMessage extends AbstractMessage {
       return new Builder(field.getMessageType());
     }
 
+    @Override
     public boolean hasOneof(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -447,11 +468,13 @@ public final class DynamicMessage extends AbstractMessage {
       return true;
     }
 
+    @Override
     public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       return oneofCases[oneof.getIndex()];
     }
 
+    @Override
     public Builder clearOneof(OneofDescriptor oneof) {
       verifyOneofContainingType(oneof);
       FieldDescriptor field = oneofCases[oneof.getIndex()];
@@ -461,11 +484,13 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public boolean hasField(FieldDescriptor field) {
       verifyContainingType(field);
       return fields.hasField(field);
     }
 
+    @Override
     public Object getField(FieldDescriptor field) {
       verifyContainingType(field);
       Object result = fields.getField(field);
@@ -481,6 +506,7 @@ public final class DynamicMessage extends AbstractMessage {
       return result;
     }
 
+    @Override
     public Builder setField(FieldDescriptor field, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -505,6 +531,7 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public Builder clearField(FieldDescriptor field) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -519,24 +546,27 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public int getRepeatedFieldCount(FieldDescriptor field) {
       verifyContainingType(field);
       return fields.getRepeatedFieldCount(field);
     }
 
+    @Override
     public Object getRepeatedField(FieldDescriptor field, int index) {
       verifyContainingType(field);
       return fields.getRepeatedField(field, index);
     }
 
-    public Builder setRepeatedField(FieldDescriptor field,
-                                    int index, Object value) {
+    @Override
+    public Builder setRepeatedField(FieldDescriptor field, int index, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
       fields.setRepeatedField(field, index, value);
       return this;
     }
 
+    @Override
     public Builder addRepeatedField(FieldDescriptor field, Object value) {
       verifyContainingType(field);
       ensureIsMutable();
@@ -544,10 +574,12 @@ public final class DynamicMessage extends AbstractMessage {
       return this;
     }
 
+    @Override
     public UnknownFieldSet getUnknownFields() {
       return unknownFields;
     }
 
+    @Override
     public Builder setUnknownFields(UnknownFieldSet unknownFields) {
       if (getDescriptorForType().getFile().getSyntax()
           == Descriptors.FileDescriptor.Syntax.PROTO3) {
diff --git a/java/core/src/main/java/com/google/protobuf/Extension.java b/java/core/src/main/java/com/google/protobuf/Extension.java
index 68d29f33..08ec5b45 100644
--- a/java/core/src/main/java/com/google/protobuf/Extension.java
+++ b/java/core/src/main/java/com/google/protobuf/Extension.java
@@ -42,6 +42,7 @@ public abstract class Extension<ContainingType extends MessageLite, Type>
   public abstract Descriptors.FieldDescriptor getDescriptor();
 
   /** Returns whether or not this extension is a Lite Extension. */
+  @Override
   final boolean isLite() {
     return false;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/FieldSet.java b/java/core/src/main/java/com/google/protobuf/FieldSet.java
index 47924b65..4e89709f 100644
--- a/java/core/src/main/java/com/google/protobuf/FieldSet.java
+++ b/java/core/src/main/java/com/google/protobuf/FieldSet.java
@@ -120,6 +120,25 @@ final class FieldSet<FieldDescriptorType extends
   public boolean isImmutable() {
     return isImmutable;
   }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof FieldSet)) {
+      return false;
+    }
+    
+    FieldSet<?> other = (FieldSet<?>) o;
+    return other.fields.equals(other.fields);
+  }
+  
+  @Override
+  public int hashCode() {
+    return fields.hashCode();
+  }
 
   /**
    * Clones the FieldSet. The returned FieldSet will be mutable even if the
diff --git a/java/core/src/main/java/com/google/protobuf/FloatArrayList.java b/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
index 033b5eed..63cb6d77 100644
--- a/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/FloatArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.FloatList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class FloatArrayList extends AbstractProtobufList<Float> implements FloatList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final FloatArrayList EMPTY_LIST = new FloatArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class FloatArrayList extends AbstractProtobufList<Float> implements FloatL
    * Constructs a new mutable {@code FloatArrayList} with default capacity.
    */
   FloatArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code FloatArrayList} with the provided capacity.
-   */
-  FloatArrayList(int capacity) {
-    array = new float[capacity];
-    size = 0;
+    this(new float[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code FloatArrayList} containing the same elements as {@code other}.
    */
-  FloatArrayList(List<Float> other) {
-    if (other instanceof FloatArrayList) {
-      FloatArrayList list = (FloatArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new float[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private FloatArrayList(float[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof FloatArrayList)) {
+      return super.equals(o);
+    }
+    FloatArrayList other = (FloatArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final float[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Float.floatToIntBits(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public FloatList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new FloatArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
index a50afe55..790cb622 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessage.java
@@ -80,6 +80,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     unknownFields = builder.getUnknownFields();
   }
 
+  @Override
   public Parser<? extends GeneratedMessage> getParserForType() {
     throw new UnsupportedOperationException(
         "This is supposed to be overridden by subclasses.");
@@ -102,7 +103,7 @@ public abstract class GeneratedMessage extends AbstractMessage
    */
   protected abstract FieldAccessorTable internalGetFieldAccessorTable();
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Descriptor getDescriptorForType() {
     return internalGetFieldAccessorTable().descriptor;
   }
@@ -191,7 +192,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     return true;
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Map<FieldDescriptor, Object> getAllFields() {
     return Collections.unmodifiableMap(
         getAllFieldsMutable(/* getBytesForString = */ false));
@@ -212,22 +213,22 @@ public abstract class GeneratedMessage extends AbstractMessage
         getAllFieldsMutable(/* getBytesForString = */ true));
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean hasOneof(final OneofDescriptor oneof) {
     return internalGetFieldAccessorTable().getOneof(oneof).has(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
     return internalGetFieldAccessorTable().getOneof(oneof).get(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean hasField(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field).has(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Object getField(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field).get(this);
   }
@@ -244,19 +245,19 @@ public abstract class GeneratedMessage extends AbstractMessage
     return internalGetFieldAccessorTable().getField(field).getRaw(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public int getRepeatedFieldCount(final FieldDescriptor field) {
     return internalGetFieldAccessorTable().getField(field)
       .getRepeatedCount(this);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public Object getRepeatedField(final FieldDescriptor field, final int index) {
     return internalGetFieldAccessorTable().getField(field)
       .getRepeated(this, index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public UnknownFieldSet getUnknownFields() {
     throw new UnsupportedOperationException(
         "This is supposed to be overridden by subclasses.");
@@ -380,7 +381,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   }
 
   @SuppressWarnings("unchecked")
-  public abstract static class Builder <BuilderType extends Builder>
+  public abstract static class Builder <BuilderType extends Builder<BuilderType>>
       extends AbstractMessage.Builder<BuilderType> {
 
     private BuilderParent builderParent;
@@ -444,6 +445,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Called by the initialization and clear code paths to allow subclasses to
      * reset any of their builtin fields back to the initial values.
      */
+    @Override
     public BuilderType clear() {
       unknownFields = UnknownFieldSet.getDefaultInstance();
       onChanged();
@@ -457,12 +459,12 @@ public abstract class GeneratedMessage extends AbstractMessage
      */
     protected abstract FieldAccessorTable internalGetFieldAccessorTable();
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Descriptor getDescriptorForType() {
       return internalGetFieldAccessorTable().descriptor;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Map<FieldDescriptor, Object> getAllFields() {
       return Collections.unmodifiableMap(getAllFieldsMutable());
     }
@@ -510,39 +512,38 @@ public abstract class GeneratedMessage extends AbstractMessage
       return result;
     }
 
-    public Message.Builder newBuilderForField(
-        final FieldDescriptor field) {
+    @Override
+    public Message.Builder newBuilderForField(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).newBuilder();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Message.Builder getFieldBuilder(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).getBuilder(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field,
-        int index) {
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
       return internalGetFieldAccessorTable().getField(field).getRepeatedBuilder(
           this, index);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasOneof(final OneofDescriptor oneof) {
       return internalGetFieldAccessorTable().getOneof(oneof).has(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public FieldDescriptor getOneofFieldDescriptor(final OneofDescriptor oneof) {
       return internalGetFieldAccessorTable().getOneof(oneof).get(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasField(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field).has(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Object getField(final FieldDescriptor field) {
       Object object = internalGetFieldAccessorTable().getField(field).get(this);
       if (field.isRepeated()) {
@@ -554,52 +555,52 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
     }
 
-    public BuilderType setField(final FieldDescriptor field,
-                                final Object value) {
+    @Override
+    public BuilderType setField(final FieldDescriptor field, final Object value) {
       internalGetFieldAccessorTable().getField(field).set(this, value);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clearField(final FieldDescriptor field) {
       internalGetFieldAccessorTable().getField(field).clear(this);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clearOneof(final OneofDescriptor oneof) {
       internalGetFieldAccessorTable().getOneof(oneof).clear(this);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public int getRepeatedFieldCount(final FieldDescriptor field) {
       return internalGetFieldAccessorTable().getField(field)
           .getRepeatedCount(this);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public Object getRepeatedField(final FieldDescriptor field,
-                                   final int index) {
+    @Override
+    public Object getRepeatedField(final FieldDescriptor field, final int index) {
       return internalGetFieldAccessorTable().getField(field)
           .getRepeated(this, index);
     }
 
-    public BuilderType setRepeatedField(final FieldDescriptor field,
-                                        final int index, final Object value) {
+    @Override
+    public BuilderType setRepeatedField(
+        final FieldDescriptor field, final int index, final Object value) {
       internalGetFieldAccessorTable().getField(field)
         .setRepeated(this, index, value);
       return (BuilderType) this;
     }
 
-    public BuilderType addRepeatedField(final FieldDescriptor field,
-                                        final Object value) {
+    @Override
+    public BuilderType addRepeatedField(final FieldDescriptor field, final Object value) {
       internalGetFieldAccessorTable().getField(field).addRepeated(this, value);
       return (BuilderType) this;
     }
 
-    public BuilderType setUnknownFields(
-        final UnknownFieldSet unknownFields) {
+    @Override
+    public BuilderType setUnknownFields(final UnknownFieldSet unknownFields) {
       this.unknownFields = unknownFields;
       onChanged();
       return (BuilderType) this;
@@ -616,7 +617,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean isInitialized() {
       for (final FieldDescriptor field : getDescriptorForType().getFields()) {
         // Check that all required fields are present.
@@ -646,7 +647,7 @@ public abstract class GeneratedMessage extends AbstractMessage
       return true;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final UnknownFieldSet getUnknownFields() {
       return unknownFields;
     }
@@ -670,7 +671,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      */
     private class BuilderParentImpl implements BuilderParent {
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void markDirty() {
         onChanged();
       }
@@ -735,6 +736,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   public interface ExtendableMessageOrBuilder<
       MessageType extends ExtendableMessage> extends MessageOrBuilder {
     // Re-define for return type covariance.
+    @Override
     Message getDefaultInstanceForType();
 
     /** Check if a singular extension is present. */
@@ -795,6 +797,8 @@ public abstract class GeneratedMessage extends AbstractMessage
       extends GeneratedMessage
       implements ExtendableMessageOrBuilder<MessageType> {
 
+    private static final long serialVersionUID = 1L;
+
     private final FieldSet<FieldDescriptor> extensions;
 
     protected ExtendableMessage() {
@@ -821,9 +825,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -831,7 +834,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -842,10 +845,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -867,11 +869,10 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extensionLite,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1105,7 +1106,7 @@ public abstract class GeneratedMessage extends AbstractMessage
   @SuppressWarnings("unchecked")
   public abstract static class ExtendableBuilder<
         MessageType extends ExtendableMessage,
-        BuilderType extends ExtendableBuilder>
+        BuilderType extends ExtendableBuilder<MessageType, BuilderType>>
       extends Builder<BuilderType>
       implements ExtendableMessageOrBuilder<MessageType> {
 
@@ -1157,9 +1158,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1167,7 +1167,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extensionLite) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
@@ -1178,9 +1178,8 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extensionLite) {
+    @Override
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extensionLite) {
       Extension<MessageType, Type> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1202,10 +1201,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extensionLite,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extensionLite, final int index) {
       Extension<MessageType, List<Type>> extension = checkNotLite(extensionLite);
 
       verifyExtensionContainingType(extension);
@@ -1458,10 +1456,9 @@ public abstract class GeneratedMessage extends AbstractMessage
     // obtained.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
-          //@Override (Java 1.6 override semantics, but we must support 1.5)
+          @Override
           public FieldDescriptor loadDescriptor() {
-            return scope.getDescriptorForType().getExtensions()
-                .get(descriptorIndex);
+            return scope.getDescriptorForType().getExtensions().get(descriptorIndex);
           }
         },
         singularType,
@@ -1489,6 +1486,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     private volatile FieldDescriptor descriptor;
     protected abstract FieldDescriptor loadDescriptor();
 
+    @Override
     public FieldDescriptor getDescriptor() {
       if (descriptor == null) {
         synchronized (this) {
@@ -1518,6 +1516,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     // obtained.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
+          @Override
           protected FieldDescriptor loadDescriptor() {
             return scope.getDescriptorForType().findFieldByName(name);
           }
@@ -1544,17 +1543,18 @@ public abstract class GeneratedMessage extends AbstractMessage
     // used to obtain the extension's FieldDescriptor.
     return new GeneratedExtension<ContainingType, Type>(
         new CachedDescriptorRetriever() {
+          @Override
           protected FieldDescriptor loadDescriptor() {
             try {
-              Class clazz =
-                  singularType.getClassLoader().loadClass(descriptorOuterClass);
-              FileDescriptor file =
-                  (FileDescriptor) clazz.getField("descriptor").get(null);
+              Class clazz = singularType.getClassLoader().loadClass(descriptorOuterClass);
+              FileDescriptor file = (FileDescriptor) clazz.getField("descriptor").get(null);
               return file.findExtensionByName(extensionName);
             } catch (Exception e) {
               throw new RuntimeException(
-                  "Cannot load descriptors: " + descriptorOuterClass +
-                  " is not a valid descriptor class name", e);
+                  "Cannot load descriptors: "
+                      + descriptorOuterClass
+                      + " is not a valid descriptor class name",
+                  e);
             }
           }
         },
@@ -1636,12 +1636,13 @@ public abstract class GeneratedMessage extends AbstractMessage
       if (descriptorRetriever != null) {
         throw new IllegalStateException("Already initialized.");
       }
-      descriptorRetriever = new ExtensionDescriptorRetriever() {
-          //@Override (Java 1.6 override semantics, but we must support 1.5)
-          public FieldDescriptor getDescriptor() {
-            return descriptor;
-          }
-        };
+      descriptorRetriever =
+          new ExtensionDescriptorRetriever() {
+            @Override
+            public FieldDescriptor getDescriptor() {
+              return descriptor;
+            }
+          };
     }
 
     private ExtensionDescriptorRetriever descriptorRetriever;
@@ -1651,6 +1652,7 @@ public abstract class GeneratedMessage extends AbstractMessage
     private final Method enumGetValueDescriptor;
     private final ExtensionType extensionType;
 
+    @Override
     public FieldDescriptor getDescriptor() {
       if (descriptorRetriever == null) {
         throw new IllegalStateException(
@@ -1663,10 +1665,12 @@ public abstract class GeneratedMessage extends AbstractMessage
      * If the extension is an embedded message or group, returns the default
      * instance of the message.
      */
+    @Override
     public Message getMessageDefaultInstance() {
       return messageDefaultInstance;
     }
 
+    @Override
     protected ExtensionType getExtensionType() {
       return extensionType;
     }
@@ -1677,7 +1681,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * EnumValueDescriptors but the native accessors use the generated enum
      * type.
      */
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     protected Object fromReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
@@ -1702,7 +1706,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Like {@link #fromReflectionType(Object)}, but if the type is a repeated
      * type, this converts a single element.
      */
-    // @Override
+    @Override
     protected Object singularFromReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
       switch (descriptor.getJavaType()) {
@@ -1726,7 +1730,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * EnumValueDescriptors but the native accessors use the generated enum
      * type.
      */
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     protected Object toReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
@@ -1750,7 +1754,7 @@ public abstract class GeneratedMessage extends AbstractMessage
      * Like {@link #toReflectionType(Object)}, but if the type is a repeated
      * type, this converts a single element.
      */
-    // @Override
+    @Override
     protected Object singularToReflectionType(final Object value) {
       FieldDescriptor descriptor = getDescriptor();
       switch (descriptor.getJavaType()) {
@@ -1761,22 +1765,22 @@ public abstract class GeneratedMessage extends AbstractMessage
       }
     }
 
-    // @Override
+    @Override
     public int getNumber() {
       return getDescriptor().getNumber();
     }
 
-    // @Override
+    @Override
     public WireFormat.FieldType getLiteType() {
       return getDescriptor().getLiteType();
     }
 
-    // @Override
+    @Override
     public boolean isRepeated() {
       return getDescriptor().isRepeated();
     }
 
-    // @Override
+    @Override
     @SuppressWarnings("unchecked")
     public Type getDefaultValue() {
       if (isRepeated()) {
@@ -2126,49 +2130,57 @@ public abstract class GeneratedMessage extends AbstractMessage
         return ((Internal.EnumLite) invokeOrDie(caseMethodBuilder, builder)).getNumber();
       }
 
+      @Override
       public Object get(final GeneratedMessage message) {
         return invokeOrDie(getMethod, message);
       }
+      @Override
       public Object get(GeneratedMessage.Builder builder) {
         return invokeOrDie(getMethodBuilder, builder);
       }
+      @Override
       public Object getRaw(final GeneratedMessage message) {
         return get(message);
       }
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
+      @Override
       public void set(final Builder builder, final Object value) {
         invokeOrDie(setMethod, builder, value);
       }
-      public Object getRepeated(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeated(final GeneratedMessage message, final int index) {
         throw new UnsupportedOperationException(
           "getRepeatedField() called on a singular field.");
       }
-      public Object getRepeatedRaw(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeatedRaw(final GeneratedMessage message, final int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldRaw() called on a singular field.");
       }
+      @Override
       public Object getRepeated(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedField() called on a singular field.");
       }
-      public Object getRepeatedRaw(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Object getRepeatedRaw(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldRaw() called on a singular field.");
       }
-      public void setRepeated(final Builder builder, final int index,
-          final Object value) {
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
         throw new UnsupportedOperationException(
           "setRepeatedField() called on a singular field.");
       }
+      @Override
       public void addRepeated(final Builder builder, final Object value) {
         throw new UnsupportedOperationException(
           "addRepeatedField() called on a singular field.");
       }
+      @Override
       public boolean has(final GeneratedMessage message) {
         if (!hasHasMethod) {
           if (isOneofField) {
@@ -2178,6 +2190,7 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
         return (Boolean) invokeOrDie(hasMethod, message);
       }
+      @Override
       public boolean has(GeneratedMessage.Builder builder) {
         if (!hasHasMethod) {
           if (isOneofField) {
@@ -2187,27 +2200,32 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
         return (Boolean) invokeOrDie(hasMethodBuilder, builder);
       }
+      @Override
       public int getRepeatedCount(final GeneratedMessage message) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldSize() called on a singular field.");
       }
+      @Override
       public int getRepeatedCount(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldSize() called on a singular field.");
       }
+      @Override
       public void clear(final Builder builder) {
         invokeOrDie(clearMethod, builder);
       }
+      @Override
       public Message.Builder newBuilder() {
         throw new UnsupportedOperationException(
           "newBuilderForField() called on a non-Message type.");
       }
+      @Override
       public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getFieldBuilder() called on a non-Message type.");
       }
-      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on a non-Message type.");
       }
@@ -2251,18 +2269,23 @@ public abstract class GeneratedMessage extends AbstractMessage
         clearMethod = getMethodOrDie(builderClass, "clear" + camelCaseName);
       }
 
+      @Override
       public Object get(final GeneratedMessage message) {
         return invokeOrDie(getMethod, message);
       }
+      @Override
       public Object get(GeneratedMessage.Builder builder) {
         return invokeOrDie(getMethodBuilder, builder);
       }
+      @Override
       public Object getRaw(final GeneratedMessage message) {
         return get(message);
       }
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
+      @Override
       public void set(final Builder builder, final Object value) {
         // Add all the elements individually.  This serves two purposes:
         // 1) Verifies that each element has the correct type.
@@ -2273,54 +2296,64 @@ public abstract class GeneratedMessage extends AbstractMessage
           addRepeated(builder, element);
         }
       }
-      public Object getRepeated(final GeneratedMessage message,
-                                final int index) {
+      @Override
+      public Object getRepeated(final GeneratedMessage message, final int index) {
         return invokeOrDie(getRepeatedMethod, message, index);
       }
+      @Override
       public Object getRepeated(GeneratedMessage.Builder builder, int index) {
         return invokeOrDie(getRepeatedMethodBuilder, builder, index);
       }
+      @Override
       public Object getRepeatedRaw(GeneratedMessage message, int index) {
         return getRepeated(message, index);
       }
-      public Object getRepeatedRaw(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Object getRepeatedRaw(GeneratedMessage.Builder builder, int index) {
         return getRepeated(builder, index);
       }
-      public void setRepeated(final Builder builder,
-                              final int index, final Object value) {
+      @Override
+      public void setRepeated(final Builder builder, final int index, final Object value) {
         invokeOrDie(setRepeatedMethod, builder, index, value);
       }
+      @Override
       public void addRepeated(final Builder builder, final Object value) {
         invokeOrDie(addRepeatedMethod, builder, value);
       }
+      @Override
       public boolean has(final GeneratedMessage message) {
         throw new UnsupportedOperationException(
           "hasField() called on a repeated field.");
       }
+      @Override
       public boolean has(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "hasField() called on a repeated field.");
       }
+      @Override
       public int getRepeatedCount(final GeneratedMessage message) {
         return (Integer) invokeOrDie(getCountMethod, message);
       }
+      @Override
       public int getRepeatedCount(GeneratedMessage.Builder builder) {
         return (Integer) invokeOrDie(getCountMethodBuilder, builder);
       }
+      @Override
       public void clear(final Builder builder) {
         invokeOrDie(clearMethod, builder);
       }
+      @Override
       public Message.Builder newBuilder() {
         throw new UnsupportedOperationException(
           "newBuilderForField() called on a non-Message type.");
       }
+      @Override
       public Message.Builder getBuilder(GeneratedMessage.Builder builder) {
         throw new UnsupportedOperationException(
           "getFieldBuilder() called on a non-Message type.");
       }
-      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder,
-          int index) {
+      @Override
+      public Message.Builder getRepeatedBuilder(GeneratedMessage.Builder builder, int index) {
         throw new UnsupportedOperationException(
           "getRepeatedFieldBuilder() called on a non-Message type.");
       }
@@ -2357,6 +2390,7 @@ public abstract class GeneratedMessage extends AbstractMessage
             field.getNumber());
       }
 
+      @Override
       public Object get(GeneratedMessage message) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(message); i++) {
@@ -2365,6 +2399,7 @@ public abstract class GeneratedMessage extends AbstractMessage
         return Collections.unmodifiableList(result);
       }
 
+      @Override
       public Object get(Builder builder) {
         List result = new ArrayList();
         for (int i = 0; i < getRepeatedCount(builder); i++) {
@@ -2373,14 +2408,17 @@ public abstract class GeneratedMessage extends AbstractMessage
         return Collections.unmodifiableList(result);
       }
 
+      @Override
       public Object getRaw(GeneratedMessage message) {
         return get(message);
       }
 
+      @Override
       public Object getRaw(GeneratedMessage.Builder builder) {
         return get(builder);
       }
 
+      @Override
       public void set(Builder builder, Object value) {
         clear(builder);
         for (Object entry : (List) value) {
@@ -2388,63 +2426,76 @@ public abstract class GeneratedMessage extends AbstractMessage
         }
       }
 
+      @Override
       public Object getRepeated(GeneratedMessage message, int index) {
         return getMapField(message).getList().get(index);
       }
 
+      @Override
       public Object getRepeated(Builder builder, int index) {
         return getMapField(builder).getList().get(index);
       }
 
+      @Override
       public Object getRepeatedRaw(GeneratedMessage message, int index) {
         return getRepeated(message, index);
       }
 
+      @Override
       public Object getRepeatedRaw(Builder builder, int index) {
         return getRepeated(builder, index);
       }
 
+      @Override
       public void setRepeated(Builder builder, int index, Object value) {
         getMutableMapField(builder).getMutableList().set(index, (Message) value);
       }
 
+      @Override
       public void addRepeated(Builder builder, Object value) {
         getMutableMapField(builder).getMutableList().add((Message) value);
       }
 
+      @Override
       public boolean has(GeneratedMessage message) {
         throw new UnsupportedOperationException(
             "hasField() is not supported for repeated fields.");
       }
 
+      @Override
       public boolean has(Builder builder) {
         throw new UnsupportedOperationException(
             "hasField() is not supported for repeated fields.");
       }
 
+      @Override
       public int getRepeatedCount(GeneratedMessage message) {
         return getMapField(message).getList().size();
       }
 
+      @Override
       public int getRepeatedCount(Builder builder) {
         return getMapField(builder).getList().size();
       }
 
+      @Override
       public void clear(Builder builder) {
         getMutableMapField(builder).getMutableList().clear();
       }
 
+      @Override
       public com.google.protobuf.Message.Builder newBuilder() {
         return mapEntryMessageDefaultInstance.newBuilderForType();
       }
 
+      @Override
       public com.google.protobuf.Message.Builder getBuilder(Builder builder) {
         throw new UnsupportedOperationException(
             "Nested builder not supported for map fields.");
       }
 
-      public com.google.protobuf.Message.Builder getRepeatedBuilder(
-          Builder builder, int index) {
+      @Override
+      public com.google.protobuf.Message.Builder getRepeatedBuilder(Builder builder, int index) {
         throw new UnsupportedOperationException(
             "Nested builder not supported for map fields.");
       }
diff --git a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
index 12a1472d..c5adc5ad 100644
--- a/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/GeneratedMessageLite.java
@@ -31,6 +31,7 @@
 package com.google.protobuf;
 
 import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
+import com.google.protobuf.GeneratedMessageLite.EqualsVisitor.NotEqualsException;
 import com.google.protobuf.Internal.BooleanList;
 import com.google.protobuf.Internal.DoubleList;
 import com.google.protobuf.Internal.FloatList;
@@ -59,24 +60,27 @@ import java.util.Map;
 public abstract class GeneratedMessageLite<
     MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
     BuilderType extends GeneratedMessageLite.Builder<MessageType, BuilderType>> 
-        extends AbstractMessageLite {
+        extends AbstractMessageLite<MessageType, BuilderType> {
 
   /** For use by generated code only. Lazily initialized to reduce allocations. */
-  protected UnknownFieldSetLite unknownFields = null;
+  protected UnknownFieldSetLite unknownFields = UnknownFieldSetLite.getDefaultInstance();
   
   /** For use by generated code only.  */
   protected int memoizedSerializedSize = -1;
   
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final Parser<MessageType> getParserForType() {
     return (Parser<MessageType>) dynamicMethod(MethodToInvoke.GET_PARSER);
   }
 
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final MessageType getDefaultInstanceForType() {
     return (MessageType) dynamicMethod(MethodToInvoke.GET_DEFAULT_INSTANCE);
   }
 
+  @Override
   @SuppressWarnings("unchecked") // Guaranteed by runtime.
   public final BuilderType newBuilderForType() {
     return (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
@@ -99,7 +103,65 @@ public abstract class GeneratedMessageLite<
     return MessageLiteToString.toString(this, super.toString());
   }
 
+  @SuppressWarnings("unchecked") // Guaranteed by runtime
+  @Override
+  public int hashCode() {
+    if (memoizedHashCode == 0) {
+      HashCodeVisitor visitor = new HashCodeVisitor();
+      visit(visitor, (MessageType) this);
+      memoizedHashCode = visitor.hashCode;
+    }
+    return memoizedHashCode;
+  }
+  
+  @SuppressWarnings("unchecked") // Guaranteed by runtime
+  int hashCode(HashCodeVisitor visitor) {
+    if (memoizedHashCode == 0) {
+      int inProgressHashCode = visitor.hashCode;
+      visitor.hashCode = 0;
+      visit(visitor, (MessageType) this);
+      memoizedHashCode = visitor.hashCode;
+      visitor.hashCode = inProgressHashCode;
+    }
+    return memoizedHashCode;
+  }
+  
+  @SuppressWarnings("unchecked") // Guaranteed by isInstance + runtime
+  @Override
+  public boolean equals(Object other) {
+    if (this == other) {
+      return true;
+    }
+    
+    if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+      return false;
+    }
+    
+    try {
+      visit(EqualsVisitor.INSTANCE, (MessageType) other);
+    } catch (NotEqualsException e) {
+      return false;
+    }
+    return true;
+  }
+  
+  /**
+   * Same as {@link #equals(Object)} but throws {@code NotEqualsException}.
+   */
+  @SuppressWarnings("unchecked") // Guaranteed by isInstance + runtime
+  boolean equals(EqualsVisitor visitor, MessageLite other) {
+    if (this == other) {
+      return true;
+    }
+    
+    if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+      return false;
+    }
 
+    visit(visitor, (MessageType) other);
+    return true;
+  }
+  
   // The general strategy for unknown fields is to use an UnknownFieldSetLite that is treated as
   // mutable during the parsing constructor and immutable after. This allows us to avoid
   // any unnecessary intermediary allocations while reducing the generated code size.
@@ -108,7 +170,7 @@ public abstract class GeneratedMessageLite<
    * Lazily initializes unknown fields.
    */
   private final void ensureUnknownFieldsInitialized() {
-    if (unknownFields == null) {
+    if (unknownFields == UnknownFieldSetLite.getDefaultInstance()) {
       unknownFields = UnknownFieldSetLite.newInstance();
     }
   }
@@ -147,18 +209,18 @@ public abstract class GeneratedMessageLite<
   /**
    * Called by subclasses to complete parsing. For use by generated code only.
    */
-  protected void doneParsing() {
-    if (unknownFields == null) {
-      unknownFields = UnknownFieldSetLite.getDefaultInstance();
-    } else {
-      unknownFields.makeImmutable();
-    }
+  protected void makeImmutable() {
+    dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
+
+    unknownFields.makeImmutable();
   }
 
+  @Override
   public final boolean isInitialized() {
     return dynamicMethod(MethodToInvoke.IS_INITIALIZED, Boolean.TRUE) != null;
   }
 
+  @Override
   public final BuilderType toBuilder() {
     BuilderType builder = (BuilderType) dynamicMethod(MethodToInvoke.NEW_BUILDER);
     builder.mergeFrom((MessageType) this);
@@ -172,11 +234,14 @@ public abstract class GeneratedMessageLite<
    * For use by generated code only.
    */
   public static enum MethodToInvoke {
+    // Rely on/modify instance state
     IS_INITIALIZED,
-    PARSE_PARTIAL_FROM,
-    MERGE_FROM,
+    VISIT,
+    MERGE_FROM_STREAM,
     MAKE_IMMUTABLE,
-    NEW_INSTANCE,
+
+    // Rely on static state
+    NEW_MUTABLE_INSTANCE,
     NEW_BUILDER,
     GET_DEFAULT_INSTANCE,
     GET_PARSER;
@@ -188,17 +253,18 @@ public abstract class GeneratedMessageLite<
    * builders in the runtime. This method bundles those operations to reduce the generated methods
    * count.
    * <ul>
-   * <li>{@code PARSE_PARTIAL_FROM} is parameterized with an {@link CodedInputStream} and
+   * <li>{@code MERGE_FROM_STREAM} is parameterized with an {@link CodedInputStream} and
    * {@link ExtensionRegistryLite}. It consumes the input stream, parsing the contents into the
    * returned protocol buffer. If parsing throws an {@link InvalidProtocolBufferException}, the
-   * implementation wraps it in a RuntimeException
-   * <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer
+   * implementation wraps it in a RuntimeException.
+   * <li>{@code NEW_INSTANCE} returns a new instance of the protocol buffer that has not yet been
+   * made immutable. See {@code MAKE_IMMUTABLE}.
    * <li>{@code IS_INITIALIZED} is parameterized with a {@code Boolean} detailing whether to
    * memoize. It returns {@code null} for false and the default instance for true. We optionally
    * memoize to support the Builder case, where memoization is not desired.
    * <li>{@code NEW_BUILDER} returns a {@code BuilderType} instance.
-   * <li>{@code MERGE_FROM} is parameterized with a {@code MessageType} and merges the fields from
-   * that instance into this instance.
+   * <li>{@code VISIT} is parameterized with a {@code Visitor} and a {@code MessageType} and
+   * recursively iterates through the fields side by side between this and the instance.
    * <li>{@code MAKE_IMMUTABLE} sets all internal fields to an immutable state.
    * </ul>
    * This method, plus the implementation of the Builder, enables the Builder class to be proguarded
@@ -222,6 +288,11 @@ public abstract class GeneratedMessageLite<
     return dynamicMethod(method, null, null);
   }
 
+  void visit(Visitor visitor, MessageType other) {
+    dynamicMethod(MethodToInvoke.VISIT, visitor, other);
+    unknownFields = visitor.visitUnknownFields(unknownFields, other.unknownFields);
+  }
+  
   /**
    * Merge some unknown fields into the {@link UnknownFieldSetLite} for this
    * message.
@@ -236,7 +307,7 @@ public abstract class GeneratedMessageLite<
   public abstract static class Builder<
       MessageType extends GeneratedMessageLite<MessageType, BuilderType>,
       BuilderType extends Builder<MessageType, BuilderType>>
-          extends AbstractMessageLite.Builder<BuilderType> {
+          extends AbstractMessageLite.Builder<MessageType, BuilderType> {
 
     private final MessageType defaultInstance;
     protected MessageType instance;
@@ -244,7 +315,8 @@ public abstract class GeneratedMessageLite<
 
     protected Builder(MessageType defaultInstance) {
       this.defaultInstance = defaultInstance;
-      this.instance = (MessageType) defaultInstance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
+      this.instance =
+          (MessageType) defaultInstance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
       isBuilt = false;
     }
 
@@ -254,26 +326,27 @@ public abstract class GeneratedMessageLite<
      */
     protected void copyOnWrite() {
       if (isBuilt) {
-        MessageType newInstance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
-        newInstance.dynamicMethod(MethodToInvoke.MERGE_FROM, instance);
+        MessageType newInstance =
+            (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
+        newInstance.visit(MergeFromVisitor.INSTANCE, instance);
         instance = newInstance;
         isBuilt = false;
       }
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final boolean isInitialized() {
       return GeneratedMessageLite.isInitialized(instance, false /* shouldMemoize */);
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final BuilderType clear() {
       // No need to copy on write since we're dropping the instance anyways.
-      instance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_INSTANCE);
+      instance = (MessageType) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
       return (BuilderType) this;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public BuilderType clone() {
       BuilderType builder =
           (BuilderType) getDefaultInstanceForType().newBuilderForType();
@@ -281,20 +354,19 @@ public abstract class GeneratedMessageLite<
       return builder;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public MessageType buildPartial() {
       if (isBuilt) {
         return instance;
       }
       
-      instance.dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
-      instance.unknownFields.makeImmutable();
+      instance.makeImmutable();
       
       isBuilt = true;
       return instance;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final MessageType build() {
       MessageType result = buildPartial();
       if (!result.isInitialized()) {
@@ -303,32 +375,36 @@ public abstract class GeneratedMessageLite<
       return result;
     }
     
+    @Override
+    protected BuilderType internalMergeFrom(MessageType message) {
+      return mergeFrom(message);
+    }
+    
     /** All subclasses implement this. */
     public BuilderType mergeFrom(MessageType message) {
       copyOnWrite();
-      instance.dynamicMethod(MethodToInvoke.MERGE_FROM, message);
+      instance.visit(MergeFromVisitor.INSTANCE, message);
       return (BuilderType) this;
     }
     
+    @Override
     public MessageType getDefaultInstanceForType() {
       return defaultInstance;
     }
     
+    @Override
     public BuilderType mergeFrom(
         com.google.protobuf.CodedInputStream input,
         com.google.protobuf.ExtensionRegistryLite extensionRegistry)
-        throws java.io.IOException {
-      MessageType parsedMessage = null;
+        throws IOException {
+      copyOnWrite();
       try {
-        parsedMessage = parsePartialFrom(
-            (MessageType) getDefaultInstanceForType(), input, extensionRegistry);
-      } catch (InvalidProtocolBufferException e) {
-        parsedMessage = (MessageType) e.getUnfinishedMessage();
-        throw e;
-      } finally {
-        if (parsedMessage != null) {
-          mergeFrom(parsedMessage);
+        instance.dynamicMethod(MethodToInvoke.MERGE_FROM_STREAM, input, extensionRegistry);
+      } catch (RuntimeException e) {
+        if (e.getCause() instanceof IOException) {
+          throw (IOException) e.getCause();
         }
+        throw e;
       }
       return (BuilderType) this;
     }
@@ -384,6 +460,12 @@ public abstract class GeneratedMessageLite<
       }
       extensions.mergeFrom(((ExtendableMessage) other).extensions);
     }
+
+    @Override
+    final void visit(Visitor visitor, MessageType other) {
+      super.visit(visitor, other);
+      extensions = visitor.visitExtensions(extensions, other.extensions);
+    }
     
     /**
      * Parse an unknown field or an extension. For use by generated code only.
@@ -521,9 +603,8 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
       GeneratedExtension<MessageType, Type> extensionLite =
           checkIsLite(extension);
       
@@ -532,7 +613,7 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extension) {
       GeneratedExtension<MessageType, List<Type>> extensionLite =
@@ -543,10 +624,9 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
       GeneratedExtension<MessageType, Type> extensionLite =
           checkIsLite(extension);
       
@@ -560,11 +640,10 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get one element of a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extension,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extension, final int index) {
       GeneratedExtension<MessageType, List<Type>> extensionLite =
           checkIsLite(extension);
 
@@ -579,8 +658,8 @@ public abstract class GeneratedMessageLite<
     }
 
     @Override
-    protected final void doneParsing() {
-      super.doneParsing();
+    protected final void makeImmutable() {
+      super.makeImmutable();
       
       extensions.makeImmutable();
     }
@@ -669,7 +748,7 @@ public abstract class GeneratedMessageLite<
       instance.extensions = extensions;
     }
 
-    // @Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     protected void copyOnWrite() {
       if (!isBuilt) {
         return;
@@ -679,7 +758,7 @@ public abstract class GeneratedMessageLite<
       instance.extensions = instance.extensions.clone();
     }
 
-    // @Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final MessageType buildPartial() {
       if (isBuilt) {
         return instance;
@@ -701,33 +780,30 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Check if a singular extension is present. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
-    public final <Type> boolean hasExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    @Override
+    public final <Type> boolean hasExtension(final ExtensionLite<MessageType, Type> extension) {
       return instance.hasExtension(extension);
     }
 
     /** Get the number of elements in a repeated extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public final <Type> int getExtensionCount(
         final ExtensionLite<MessageType, List<Type>> extension) {
       return instance.getExtensionCount(extension);
     }
 
     /** Get the value of an extension. */
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     @SuppressWarnings("unchecked")
-    public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, Type> extension) {
+    public final <Type> Type getExtension(final ExtensionLite<MessageType, Type> extension) {
       return instance.getExtension(extension);
     }
 
     /** Get one element of a repeated extension. */
+    @Override
     @SuppressWarnings("unchecked")
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
     public final <Type> Type getExtension(
-        final ExtensionLite<MessageType, List<Type>> extension,
-        final int index) {
+        final ExtensionLite<MessageType, List<Type>> extension, final int index) {
       return instance.getExtension(extension, index);
     }
 
@@ -859,37 +935,44 @@ public abstract class GeneratedMessageLite<
     final boolean isRepeated;
     final boolean isPacked;
 
+    @Override
     public int getNumber() {
       return number;
     }
 
+    @Override
     public WireFormat.FieldType getLiteType() {
       return type;
     }
 
+    @Override
     public WireFormat.JavaType getLiteJavaType() {
       return type.getJavaType();
     }
 
+    @Override
     public boolean isRepeated() {
       return isRepeated;
     }
 
+    @Override
     public boolean isPacked() {
       return isPacked;
     }
 
+    @Override
     public Internal.EnumLiteMap<?> getEnumType() {
       return enumTypeMap;
     }
 
+    @Override
     @SuppressWarnings("unchecked")
-    public MessageLite.Builder internalMergeFrom(
-        MessageLite.Builder to, MessageLite from) {
+    public MessageLite.Builder internalMergeFrom(MessageLite.Builder to, MessageLite from) {
       return ((Builder) to).mergeFrom((GeneratedMessageLite) from);
     }
 
 
+    @Override
     public int compareTo(ExtensionDescriptor other) {
       return number - other.number;
     }
@@ -984,6 +1067,7 @@ public abstract class GeneratedMessageLite<
     }
 
     /** Get the field number. */
+    @Override
     public int getNumber() {
       return descriptor.getNumber();
     }
@@ -993,6 +1077,7 @@ public abstract class GeneratedMessageLite<
      * If the extension is an embedded message or group, returns the default
      * instance of the message.
      */
+    @Override
     public MessageLite getMessageDefaultInstance() {
       return messageDefaultInstance;
     }
@@ -1047,14 +1132,17 @@ public abstract class GeneratedMessageLite<
       }
     }
 
+    @Override
     public FieldType getLiteType() {
       return descriptor.getLiteType();
     }
 
+    @Override
     public boolean isRepeated() {
       return descriptor.isRepeated;
     }
 
+    @Override
     public Type getDefaultValue() {
       return defaultValue;
     }
@@ -1139,112 +1227,72 @@ public abstract class GeneratedMessageLite<
   protected static final <T extends GeneratedMessageLite<T, ?>> boolean isInitialized(
       T message, boolean shouldMemoize) {
     return message.dynamicMethod(MethodToInvoke.IS_INITIALIZED, shouldMemoize) != null;
-  }
+  } 
   
   protected static final <T extends GeneratedMessageLite<T, ?>> void makeImmutable(T message) {
     message.dynamicMethod(MethodToInvoke.MAKE_IMMUTABLE);
   }
-  
-  protected static IntList newIntList() {
-    return new IntArrayList();
-  }
-  
-  protected static IntList newIntListWithCapacity(int capacity) {
-    return new IntArrayList(capacity);
-  }
-  
-  protected static IntList newIntList(List<Integer> toCopy) {
-    return new IntArrayList(toCopy);
-  }
-  
+
   protected static IntList emptyIntList() {
     return IntArrayList.emptyList();
   }
 
-  protected static LongList newLongList() {
-    return new LongArrayList();
+  protected static IntList mutableCopy(IntList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
 
-  protected static LongList newLongListWithCapacity(int capacity) {
-    return new LongArrayList(capacity);
-  }
-  
-  protected static LongList newLongList(List<Long> toCopy) {
-    return new LongArrayList(toCopy);
-  }
-  
   protected static LongList emptyLongList() {
     return LongArrayList.emptyList();
   }
   
-  protected static FloatList newFloatList() {
-    return new FloatArrayList();
+  protected static LongList mutableCopy(LongList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static FloatList newFloatListWithCapacity(int capacity) {
-    return new FloatArrayList(capacity);
-  }
-  
-  protected static FloatList newFloatList(List<Float> toCopy) {
-    return new FloatArrayList(toCopy);
-  }
-  
+
   protected static FloatList emptyFloatList() {
     return FloatArrayList.emptyList();
   }
   
-  protected static DoubleList newDoubleList() {
-    return new DoubleArrayList();
+  protected static FloatList mutableCopy(FloatList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static DoubleList newDoubleListWithCapacity(int capacity) {
-    return new DoubleArrayList(capacity);
-  }
-  
-  protected static DoubleList newDoubleList(List<Double> toCopy) {
-    return new DoubleArrayList(toCopy);
-  }
-  
+
   protected static DoubleList emptyDoubleList() {
     return DoubleArrayList.emptyList();
   }
   
-  protected static BooleanList newBooleanList() {
-    return new BooleanArrayList();
-  }
-  
-  protected static BooleanList newBooleanListWithCapacity(int capacity) {
-    return new BooleanArrayList(capacity);
+  protected static DoubleList mutableCopy(DoubleList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
-  protected static BooleanList newBooleanList(List<Boolean> toCopy) {
-    return new BooleanArrayList(toCopy);
-  }
-  
+
   protected static BooleanList emptyBooleanList() {
     return BooleanArrayList.emptyList();
   }
   
-  protected static <E> ProtobufList<E> newProtobufList() {
-    return new ProtobufArrayList<E>();
-  }
-  
-  protected static <E> ProtobufList<E> newProtobufList(List<E> toCopy) {
-    return new ProtobufArrayList<E>(toCopy);
-  }
-  
-  protected static <E> ProtobufList<E> newProtobufListWithCapacity(int capacity) {
-    return new ProtobufArrayList<E>(capacity);
+  protected static BooleanList mutableCopy(BooleanList list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
   }
-  
+
   protected static <E> ProtobufList<E> emptyProtobufList() {
     return ProtobufArrayList.emptyList();
   }
-
-  protected static LazyStringArrayList emptyLazyStringArrayList() {
-    return LazyStringArrayList.emptyList();
-  }
   
+  protected static <E> ProtobufList<E> mutableCopy(ProtobufList<E> list) {
+    int size = list.size();
+    return list.mutableCopyWithCapacity(
+        size == 0 ? AbstractProtobufList.DEFAULT_CAPACITY : size * 2);
+  }
+
   /**
    * A {@link Parser} implementation that delegates to the default instance.
    * <p>
@@ -1274,10 +1322,11 @@ public abstract class GeneratedMessageLite<
   static <T extends GeneratedMessageLite<T, ?>> T parsePartialFrom(
       T instance, CodedInputStream input, ExtensionRegistryLite extensionRegistry)
           throws InvalidProtocolBufferException {
-    T result;
+    @SuppressWarnings("unchecked") // Guaranteed by protoc
+    T result = (T) instance.dynamicMethod(MethodToInvoke.NEW_MUTABLE_INSTANCE);
     try {
-      result = (T) instance.dynamicMethod(
-          MethodToInvoke.PARSE_PARTIAL_FROM, input, extensionRegistry);
+      result.dynamicMethod(MethodToInvoke.MERGE_FROM_STREAM, input, extensionRegistry);
+      result.makeImmutable();
     } catch (RuntimeException e) {
       if (e.getCause() instanceof InvalidProtocolBufferException) {
         throw (InvalidProtocolBufferException) e.getCause();
@@ -1454,4 +1503,740 @@ public abstract class GeneratedMessageLite<
     }
     return message;
   }
+
+  /**
+   * An abstract visitor that the generated code calls into that we use to implement various
+   * features. Fields that are not members of oneofs are always visited. Members of a oneof are only
+   * visited when they are the set oneof case value on the "other" proto. The visitOneofNotSet
+   * method is invoked if other's oneof case is not set.
+   */
+  protected interface Visitor {
+    boolean visitBoolean(boolean minePresent, boolean mine, boolean otherPresent, boolean other);
+    int visitInt(boolean minePresent, int mine, boolean otherPresent, int other);
+    double visitDouble(boolean minePresent, double mine, boolean otherPresent, double other);
+    float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other);
+    long visitLong(boolean minePresent, long mine, boolean otherPresent, long other);
+    String visitString(boolean minePresent, String mine, boolean otherPresent, String other);
+    ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other);
+
+    Object visitOneofBoolean(boolean minePresent, Object mine, Object other);
+    Object visitOneofInt(boolean minePresent, Object mine, Object other);
+    Object visitOneofDouble(boolean minePresent, Object mine, Object other);
+    Object visitOneofFloat(boolean minePresent, Object mine, Object other);
+    Object visitOneofLong(boolean minePresent, Object mine, Object other);
+    Object visitOneofString(boolean minePresent, Object mine, Object other);
+    Object visitOneofByteString(boolean minePresent, Object mine, Object other);
+    Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other);
+    Object visitOneofMessage(boolean minePresent, Object mine, Object other);
+    void visitOneofNotSet(boolean minePresent);
+    
+    /**
+     * Message fields use null sentinals.
+     */
+    <T extends MessageLite> T visitMessage(T mine, T other);
+    LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other);
+
+    <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other);
+    BooleanList visitBooleanList(BooleanList mine, BooleanList other);
+    IntList visitIntList(IntList mine, IntList other);
+    DoubleList visitDoubleList(DoubleList mine, DoubleList other);
+    FloatList visitFloatList(FloatList mine, FloatList other);
+    LongList visitLongList(LongList mine, LongList other);
+    FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine, FieldSet<ExtensionDescriptor> other);
+    UnknownFieldSetLite visitUnknownFields(UnknownFieldSetLite mine, UnknownFieldSetLite other);
+    <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other);
+  }
+
+  /**
+   * Implements equals. Throws a {@link NotEqualsException} when not equal.
+   */
+  static class EqualsVisitor implements Visitor {
+
+    static final class NotEqualsException extends RuntimeException {}
+
+    static final EqualsVisitor INSTANCE = new EqualsVisitor();
+
+    static final NotEqualsException NOT_EQUALS = new NotEqualsException();
+
+    private EqualsVisitor() {}
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      if (minePresent != otherPresent || mine != other) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      if (minePresent != otherPresent || !mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      if (minePresent != otherPresent || !mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent && ((GeneratedMessageLite<?, ?>) mine).equals(this, (MessageLite) other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+    
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      if (minePresent) {
+        throw NOT_EQUALS;
+      }
+    }
+
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      if (mine == null && other == null) {
+        return null;
+      }
+
+      if (mine == null || other == null) {
+        throw NOT_EQUALS;
+      }
+
+      ((GeneratedMessageLite<?, ?>) mine).equals(this, other);
+
+      return mine;
+    }
+    
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      if (!minePresent && !otherPresent) {
+        return mine;
+      } else if (minePresent && otherPresent && mine.equals(other)) {
+        return mine;
+      }
+      throw NOT_EQUALS;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      if (!mine.equals(other)) {
+        throw NOT_EQUALS;
+      }
+      return mine;
+    }
+  }
+
+  /**
+   * Implements hashCode by accumulating state.
+   */
+  private static class HashCodeVisitor implements Visitor {
+
+    // The caller must ensure that the visitor is invoked parameterized with this and this such that
+    // other is this. This is required due to how oneof cases are handled. See the class comment
+    // on Visitor for more information.
+    
+    private int hashCode = 0;
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      hashCode = (53 * hashCode) + Internal.hashBoolean(mine);
+      return mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      hashCode = (53 * hashCode) + mine;
+      return mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(Double.doubleToLongBits(mine));
+      return mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      hashCode = (53 * hashCode) + Float.floatToIntBits(mine);
+      return mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(mine);
+      return mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashBoolean(((Boolean) mine));
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + (Integer) mine;
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashLong(Double.doubleToLongBits((Double) mine));
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Float.floatToIntBits((Float) mine);
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + Internal.hashLong((Long) mine);
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      return visitMessage((MessageLite) mine, (MessageLite) other);
+    }
+
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      if (minePresent) {
+        throw new IllegalStateException(); // Can't happen if other == this. 
+      }
+    }
+
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      final int protoHash;
+      if (mine != null) {
+        if (mine instanceof GeneratedMessageLite) {
+          protoHash = ((GeneratedMessageLite) mine).hashCode(this);
+        } else {
+          protoHash = mine.hashCode();
+        }
+      } else {
+        protoHash = 37;
+      }
+      hashCode = (53 * hashCode) + protoHash;
+      return mine;
+    }
+
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+    
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      hashCode = (53 * hashCode) + mine.hashCode();
+      return mine;
+    }
+  }
+
+  /**
+   * Implements field merging semantics over the visitor interface.
+   */
+  protected static class MergeFromVisitor implements Visitor {
+
+    public static final MergeFromVisitor INSTANCE = new MergeFromVisitor();
+
+    private MergeFromVisitor() {}
+
+    @Override
+    public boolean visitBoolean(
+        boolean minePresent, boolean mine, boolean otherPresent, boolean other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public int visitInt(boolean minePresent, int mine, boolean otherPresent, int other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public double visitDouble(
+        boolean minePresent, double mine, boolean otherPresent, double other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public float visitFloat(boolean minePresent, float mine, boolean otherPresent, float other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public long visitLong(boolean minePresent, long mine, boolean otherPresent, long other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public String visitString(
+        boolean minePresent, String mine, boolean otherPresent, String other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public ByteString visitByteString(
+        boolean minePresent, ByteString mine, boolean otherPresent, ByteString other) {
+      return otherPresent ? other : mine;
+    }
+
+    @Override
+    public Object visitOneofBoolean(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofInt(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofDouble(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofFloat(boolean minePresent, Object mine, Object other) {
+      return other;
+    }
+
+    @Override
+    public Object visitOneofLong(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofString(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofByteString(boolean minePresent, Object mine, Object other) {
+      return other;      
+    }
+
+    @Override
+    public Object visitOneofLazyMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent) {
+        LazyFieldLite lazy = (LazyFieldLite) mine;
+        lazy.merge((LazyFieldLite) other);
+        return lazy;
+      }
+      return other;
+    }
+    
+    @Override
+    public Object visitOneofMessage(boolean minePresent, Object mine, Object other) {
+      if (minePresent) {
+        return visitMessage((MessageLite) mine, (MessageLite) other);
+      }
+      return other;
+    }
+    
+    @Override
+    public void visitOneofNotSet(boolean minePresent) {
+      return;
+    }
+
+    @SuppressWarnings("unchecked") // Guaranteed by runtime.
+    @Override
+    public <T extends MessageLite> T visitMessage(T mine, T other) {
+      if (mine != null && other != null) {
+        return (T) mine.toBuilder().mergeFrom(other).build();
+      }
+
+      return mine != null ? mine : other;
+    }
+
+    @Override
+    public LazyFieldLite visitLazyMessage(
+        boolean minePresent, LazyFieldLite mine, boolean otherPresent, LazyFieldLite other) {
+      // LazyFieldLite's are never null so we can just copy across. Necessary to avoid leakage
+      // from builder into immutable message.
+      // TODO(dweis): Change to null sentinels?
+      mine.merge(other);
+      return mine;
+    }
+
+    @Override
+    public <T> ProtobufList<T> visitList(ProtobufList<T> mine, ProtobufList<T> other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public BooleanList visitBooleanList(BooleanList mine, BooleanList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public IntList visitIntList(IntList mine, IntList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public DoubleList visitDoubleList(DoubleList mine, DoubleList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public FloatList visitFloatList(FloatList mine, FloatList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public LongList visitLongList(LongList mine, LongList other) {
+      int size = mine.size();
+      int otherSize = other.size();
+      if (size > 0 && otherSize > 0) {
+        if (!mine.isModifiable()) {
+          mine = mine.mutableCopyWithCapacity(size + otherSize);
+        }
+        mine.addAll(other);
+      }
+      
+      return size > 0 ? mine : other;
+    }
+
+    @Override
+    public FieldSet<ExtensionDescriptor> visitExtensions(
+        FieldSet<ExtensionDescriptor> mine,
+        FieldSet<ExtensionDescriptor> other) {
+      if (mine.isImmutable()) {
+        mine = mine.clone();
+      }
+      mine.mergeFrom(other);
+      return mine;
+    }
+
+    @Override
+    public UnknownFieldSetLite visitUnknownFields(
+        UnknownFieldSetLite mine,
+        UnknownFieldSetLite other) {
+      return other == UnknownFieldSetLite.getDefaultInstance()
+          ? mine : UnknownFieldSetLite.mutableCopyOf(mine, other);
+    }
+    
+    @Override
+    public <K, V> MapFieldLite<K, V> visitMap(MapFieldLite<K, V> mine, MapFieldLite<K, V> other) {
+      mine.mergeFrom(other);
+      return mine;
+    }
+  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/IntArrayList.java b/java/core/src/main/java/com/google/protobuf/IntArrayList.java
index f4e68ed8..6d6ece5a 100644
--- a/java/core/src/main/java/com/google/protobuf/IntArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/IntArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.IntList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class IntArrayList extends AbstractProtobufList<Integer> implements IntList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final IntArrayList EMPTY_LIST = new IntArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class IntArrayList extends AbstractProtobufList<Integer> implements IntLis
    * Constructs a new mutable {@code IntArrayList} with default capacity.
    */
   IntArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code IntArrayList} with the provided capacity.
-   */
-  IntArrayList(int capacity) {
-    array = new int[capacity];
-    size = 0;
+    this(new int[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code IntArrayList} containing the same elements as {@code other}.
    */
-  IntArrayList(List<Integer> other) {
-    if (other instanceof IntArrayList) {
-      IntArrayList list = (IntArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new int[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private IntArrayList(int[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof IntArrayList)) {
+      return super.equals(o);
+    }
+    IntArrayList other = (IntArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final int[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + array[i];
+    }
+    return result;
+  }
+
+  @Override
+  public IntList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new IntArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/Internal.java b/java/core/src/main/java/com/google/protobuf/Internal.java
index abf7ddd6..d1de375e 100644
--- a/java/core/src/main/java/com/google/protobuf/Internal.java
+++ b/java/core/src/main/java/com/google/protobuf/Internal.java
@@ -41,6 +41,7 @@ import java.util.Arrays;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.RandomAccess;
 import java.util.Set;
 
 /**
@@ -457,10 +458,13 @@ public final class Internal {
     public static <T extends EnumLite> Converter<Integer, T> newEnumConverter(
         final EnumLiteMap<T> enumMap, final T unrecognizedValue) {
       return new Converter<Integer, T>() {
+        @Override
         public T doForward(Integer value) {
           T result = enumMap.findValueByNumber(value);
           return result == null ? unrecognizedValue : result;
         }
+
+        @Override
         public Integer doBackward(T value) {
           return value.getNumber();
         }
@@ -573,8 +577,10 @@ public final class Internal {
   /**
    * Extends {@link List} to add the capability to make the list immutable and inspect if it is
    * modifiable.
+   * <p>
+   * All implementations must support efficient random access.
    */
-  public static interface ProtobufList<E> extends List<E> {
+  public static interface ProtobufList<E> extends List<E>, RandomAccess {
 
     /**
      * Makes this list immutable. All subsequent modifications will throw an
@@ -586,6 +592,11 @@ public final class Internal {
      * Returns whether this list can be modified via the publicly accessible {@link List} methods.
      */
     boolean isModifiable();
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    ProtobufList<E> mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -600,14 +611,20 @@ public final class Internal {
     int getInt(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Integer)} but more efficient in that it doesn't box the element.
      */
     void addInt(int element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Integer)} but more efficient in that it doesn't box the element.
      */
     int setInt(int index, int element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    IntList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -622,14 +639,20 @@ public final class Internal {
     boolean getBoolean(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Boolean)} but more efficient in that it doesn't box the element.
      */
     void addBoolean(boolean element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Boolean)} but more efficient in that it doesn't box the element.
      */
     boolean setBoolean(int index, boolean element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    BooleanList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -644,14 +667,20 @@ public final class Internal {
     long getLong(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Long)} but more efficient in that it doesn't box the element.
      */
     void addLong(long element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Long)} but more efficient in that it doesn't box the element.
      */
     long setLong(int index, long element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    LongList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -666,14 +695,20 @@ public final class Internal {
     double getDouble(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Double)} but more efficient in that it doesn't box the element.
      */
     void addDouble(double element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Double)} but more efficient in that it doesn't box the element.
      */
     double setDouble(int index, double element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    DoubleList mutableCopyWithCapacity(int capacity);
   }
 
   /**
@@ -688,13 +723,19 @@ public final class Internal {
     float getFloat(int index);
 
     /**
-     * Like {@link #add(Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #add(Float)} but more efficient in that it doesn't box the element.
      */
     void addFloat(float element);
 
     /**
-     * Like {@link #set(int, Object)} but more efficient in that it doesn't box the element.
+     * Like {@link #set(int, Float)} but more efficient in that it doesn't box the element.
      */
     float setFloat(int index, float element);
+
+    /**
+     * Returns a mutable clone of this list with the specified capacity.
+     */
+    @Override
+    FloatList mutableCopyWithCapacity(int capacity);
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyField.java b/java/core/src/main/java/com/google/protobuf/LazyField.java
index 3da8b900..98e13ca1 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyField.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyField.java
@@ -95,12 +95,12 @@ public class LazyField extends LazyFieldLite {
       this.entry = entry;
     }
 
-    // @Override
+    @Override
     public K getKey() {
       return entry.getKey();
     }
 
-    // @Override
+    @Override
     public Object getValue() {
       LazyField field = entry.getValue();
       if (field == null) {
@@ -113,7 +113,7 @@ public class LazyField extends LazyFieldLite {
       return entry.getValue();
     }
 
-    // @Override
+    @Override
     public Object setValue(Object value) {
       if (!(value instanceof MessageLite)) {
         throw new IllegalArgumentException(
@@ -131,13 +131,13 @@ public class LazyField extends LazyFieldLite {
       this.iterator = iterator;
     }
 
-    // @Override
+    @Override
     public boolean hasNext() {
       return iterator.hasNext();
     }
 
+    @Override
     @SuppressWarnings("unchecked")
-    // @Override
     public Entry<K, Object> next() {
       Entry<K, ?> entry = iterator.next();
       if (entry.getValue() instanceof LazyField) {
@@ -146,7 +146,7 @@ public class LazyField extends LazyFieldLite {
       return (Entry<K, Object>) entry;
     }
 
-    // @Override
+    @Override
     public void remove() {
       iterator.remove();
     }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java b/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
index 016ec20d..2febaace 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyFieldLite.java
@@ -135,6 +135,43 @@ public class LazyFieldLite {
     return lf;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof LazyFieldLite)) {
+      return false;
+    }
+
+    LazyFieldLite other = (LazyFieldLite) o;
+    
+    // Lazy fields do not work well with equals... If both are delayedBytes, we do not have a
+    // mechanism to deserialize them so we rely on bytes equality. Otherwise we coerce into an
+    // actual message (if necessary) and call equals on the message itself. This implies that two
+    // messages can by unequal but then be turned equal simply be invoking a getter on a lazy field.
+    MessageLite value1 = value;
+    MessageLite value2 = other.value;
+    if (value1 == null && value2 == null) {
+      return toByteString().equals(other.toByteString());
+    } else if (value1 != null && value2 != null) {
+      return value1.equals(value2);
+    } else if (value1 != null) {
+      return value1.equals(other.getValue(value1.getDefaultInstanceForType()));
+    } else {
+      return getValue(value2.getDefaultInstanceForType()).equals(value2);
+    }
+  }
+  
+  @Override
+  public int hashCode() {
+    // We can't provide a memoizable hash code for lazy fields. The byte strings may have different
+    // hash codes but evaluate to equivalent messages. And we have no facility for constructing
+    // a message here if we were not already holding a value.
+    return 1;
+  }
+  
   /**
    * Determines whether this LazyFieldLite instance represents the default instance of this type.
    */
@@ -340,6 +377,8 @@ public class LazyFieldLite {
    * parsed. Be careful when using this method.
    */
   public int getSerializedSize() {
+    // We *must* return delayed bytes size if it was ever set because the dependent messages may
+    // have memoized serialized size based off of it.
     if (memoizedBytes != null) {
       return memoizedBytes.size();
     } else if (delayedBytes != null) {
@@ -358,6 +397,8 @@ public class LazyFieldLite {
     if (memoizedBytes != null) {
       return memoizedBytes;
     }
+    // We *must* return delayed bytes if it was set because the dependent messages may have
+    // memoized serialized size based off of it.
     if (delayedBytes != null) {
       return delayedBytes;
     }
diff --git a/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java b/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
index 68c430cf..d474c51e 100644
--- a/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/LazyStringArrayList.java
@@ -64,7 +64,7 @@ import java.util.RandomAccess;
  */
 public class LazyStringArrayList extends AbstractProtobufList<String>
     implements LazyStringList, RandomAccess {
-  
+
   private static final LazyStringArrayList EMPTY_LIST = new LazyStringArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -80,11 +80,11 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
   private final List<Object> list;
 
   public LazyStringArrayList() {
-    list = new ArrayList<Object>();
+    this(DEFAULT_CAPACITY);
   }
 
   public LazyStringArrayList(int intialCapacity) {
-    list = new ArrayList<Object>(intialCapacity);
+    this(new ArrayList<Object>(intialCapacity));
   }
 
   public LazyStringArrayList(LazyStringList from) {
@@ -93,7 +93,21 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
   }
 
   public LazyStringArrayList(List<String> from) {
-    list = new ArrayList<Object>(from);
+    this(new ArrayList<Object>(from));
+  }
+  
+  private LazyStringArrayList(ArrayList<Object> list) {
+    this.list = list;
+  }
+
+  @Override
+  public LazyStringArrayList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size()) {
+      throw new IllegalArgumentException();
+    }
+    ArrayList<Object> newList = new ArrayList<Object>(capacity);
+    newList.addAll(list);
+    return new LazyStringArrayList(newList);
   }
 
   @Override
@@ -170,7 +184,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return ret;
   }
 
-  // @Override
+  @Override
   public boolean addAllByteString(Collection<? extends ByteString> values) {
     ensureIsMutable();
     boolean ret = list.addAll(values);
@@ -178,7 +192,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return ret;
   }
 
-  // @Override
+  @Override
   public boolean addAllByteArray(Collection<byte[]> c) {
     ensureIsMutable();
     boolean ret = list.addAll(c);
@@ -201,14 +215,14 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     modCount++;
   }
 
-  // @Override
+  @Override
   public void add(ByteString element) {
     ensureIsMutable();
     list.add(element);
     modCount++;
   }
   
-  // @Override
+  @Override
   public void add(byte[] element) {
     ensureIsMutable();
     list.add(element);
@@ -220,7 +234,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return list.get(index);
   }
   
-  // @Override
+  @Override
   public ByteString getByteString(int index) {
     Object o = list.get(index);
     ByteString b = asByteString(o);
@@ -230,7 +244,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return b;
   }
   
-  // @Override
+  @Override
   public byte[] getByteArray(int index) {
     Object o = list.get(index);
     byte[] b = asByteArray(o);
@@ -240,7 +254,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return b;
   }
 
-  // @Override
+  @Override
   public void set(int index, ByteString s) {
     setAndReturn(index, s);
   }
@@ -250,7 +264,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     return list.set(index, s);
   }
 
-  // @Override
+  @Override
   public void set(int index, byte[] s) {
     setAndReturn(index, s);
   }
@@ -290,12 +304,12 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
 
-  // @Override
+  @Override
   public List<?> getUnderlyingElements() {
     return Collections.unmodifiableList(list);
   }
 
-  // @Override
+  @Override
   public void mergeFrom(LazyStringList other) {
     ensureIsMutable();
     for (Object o : other.getUnderlyingElements()) {
@@ -349,7 +363,7 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
   
-  // @Override
+  @Override
   public List<byte[]> asByteArrayList() {
     return new ByteArrayListView(this);
   }
@@ -393,12 +407,12 @@ public class LazyStringArrayList extends AbstractProtobufList<String>
     }
   }
 
-  // @Override
+  @Override
   public List<ByteString> asByteStringList() {
     return new ByteStringListView(this);
   }
 
-  // @Override
+  @Override
   public LazyStringList getUnmodifiableView() {
     if (isModifiable()) {
       return new UnmodifiableLazyStringList(this);
diff --git a/java/core/src/main/java/com/google/protobuf/LongArrayList.java b/java/core/src/main/java/com/google/protobuf/LongArrayList.java
index ebe62029..bc4475d1 100644
--- a/java/core/src/main/java/com/google/protobuf/LongArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/LongArrayList.java
@@ -34,7 +34,6 @@ import com.google.protobuf.Internal.LongList;
 
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.List;
 import java.util.RandomAccess;
 
 /**
@@ -44,8 +43,6 @@ import java.util.RandomAccess;
  */
 final class LongArrayList extends AbstractProtobufList<Long> implements LongList, RandomAccess {
   
-  private static final int DEFAULT_CAPACITY = 10;
-  
   private static final LongArrayList EMPTY_LIST = new LongArrayList();
   static {
     EMPTY_LIST.makeImmutable();
@@ -70,32 +67,55 @@ final class LongArrayList extends AbstractProtobufList<Long> implements LongList
    * Constructs a new mutable {@code LongArrayList} with default capacity.
    */
   LongArrayList() {
-    this(DEFAULT_CAPACITY);
-  }
-
-  /**
-   * Constructs a new mutable {@code LongArrayList} with the provided capacity.
-   */
-  LongArrayList(int capacity) {
-    array = new long[capacity];
-    size = 0;
+    this(new long[DEFAULT_CAPACITY], 0);
   }
 
   /**
    * Constructs a new mutable {@code LongArrayList} containing the same elements as {@code other}.
    */
-  LongArrayList(List<Long> other) {
-    if (other instanceof LongArrayList) {
-      LongArrayList list = (LongArrayList) other;
-      array = list.array.clone();
-      size = list.size;
-    } else {
-      size = other.size();
-      array = new long[size];
-      for (int i = 0; i < size; i++) {
-        array[i] = other.get(i);
+  private LongArrayList(long[] array, int size) {
+    this.array = array;
+    this.size = size;
+  }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    if (!(o instanceof IntArrayList)) {
+      return super.equals(o);
+    }
+    LongArrayList other = (LongArrayList) o;
+    if (size != other.size) {
+      return false;
+    }
+    
+    final long[] arr = other.array;
+    for (int i = 0; i < size; i++) {
+      if (array[i] != arr[i]) {
+        return false;
       }
     }
+    
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = 1;
+    for (int i = 0; i < size; i++) {
+      result = (31 * result) + Internal.hashLong(array[i]);
+    }
+    return result;
+  }
+
+  @Override
+  public LongList mutableCopyWithCapacity(int capacity) {
+    if (capacity < size) {
+      throw new IllegalArgumentException();
+    }
+    return new LongArrayList(Arrays.copyOf(array, capacity), size);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/MapEntryLite.java b/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
index bcffa946..12c64abb 100644
--- a/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
+++ b/java/core/src/main/java/com/google/protobuf/MapEntryLite.java
@@ -41,7 +41,8 @@ import java.io.IOException;
  * 
  * Protobuf internal. Users shouldn't use.
  */
-public class MapEntryLite<K, V> extends AbstractMessageLite {
+public class MapEntryLite<K, V>
+    extends AbstractMessageLite<MapEntryLite<K, V>, MapEntryLite.Builder<K, V>> {
   private static class Metadata<K, V> {
     public final MapEntryLite<K, V> defaultInstance;
     public final WireFormat.FieldType keyType;
@@ -233,7 +234,7 @@ public class MapEntryLite<K, V> extends AbstractMessageLite {
    * Builder used to create {@link MapEntryLite} messages.
    */
   public static class Builder<K, V>
-      extends AbstractMessageLite.Builder<Builder<K, V>> {
+      extends AbstractMessageLite.Builder<MapEntryLite<K, V>, Builder<K, V>> {
     private final Metadata<K, V> metadata;
     private K key;
     private V value;
@@ -327,5 +328,10 @@ public class MapEntryLite<K, V> extends AbstractMessageLite {
       this.value = entry.value;
       return this;
     }
+
+    @Override
+    protected Builder<K, V> internalMergeFrom(MapEntryLite<K, V> message) {
+      throw new UnsupportedOperationException();
+    }
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MapField.java b/java/core/src/main/java/com/google/protobuf/MapField.java
index b290993c..907f0f71 100644
--- a/java/core/src/main/java/com/google/protobuf/MapField.java
+++ b/java/core/src/main/java/com/google/protobuf/MapField.java
@@ -93,15 +93,18 @@ public class MapField<K, V> implements MutabilityOracle {
       this.defaultEntry = defaultEntry;
     }
     
+    @Override
     public Message convertKeyAndValueToMessage(K key, V value) {
       return defaultEntry.newBuilderForType().setKey(key).setValue(value).buildPartial();
     }
     
+    @Override
     public void convertMessageToKeyAndValue(Message message, Map<K, V> map) {
       MapEntry<K, V> entry = (MapEntry<K, V>) message;
       map.put(entry.getKey(), entry.getValue());
     }
 
+    @Override
     public Message getMessageDefaultInstance() {
       return defaultEntry;
     }
diff --git a/java/core/src/main/java/com/google/protobuf/Message.java b/java/core/src/main/java/com/google/protobuf/Message.java
index 9516d71f..94590fb9 100644
--- a/java/core/src/main/java/com/google/protobuf/Message.java
+++ b/java/core/src/main/java/com/google/protobuf/Message.java
@@ -51,6 +51,7 @@ import java.util.Map;
 public interface Message extends MessageLite, MessageOrBuilder {
 
   // (From MessageLite, re-declared here only for return type covariance.)
+  @Override
   Parser<? extends Message> getParserForType();
 
 
@@ -97,7 +98,10 @@ public interface Message extends MessageLite, MessageOrBuilder {
   // Builders
 
   // (From MessageLite, re-declared here only for return type covariance.)
+  @Override
   Builder newBuilderForType();
+
+  @Override
   Builder toBuilder();
 
   /**
@@ -106,6 +110,7 @@ public interface Message extends MessageLite, MessageOrBuilder {
   interface Builder extends MessageLite.Builder, MessageOrBuilder {
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Builder clear();
 
     /**
@@ -131,18 +136,27 @@ public interface Message extends MessageLite, MessageOrBuilder {
 
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Message build();
+
+    @Override
     Message buildPartial();
+
+    @Override
     Builder clone();
+
+    @Override
     Builder mergeFrom(CodedInputStream input) throws IOException;
-    Builder mergeFrom(CodedInputStream input,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws IOException;
+
+    @Override
+    Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
 
     /**
      * Get the message's type's descriptor.
      * See {@link Message#getDescriptorForType()}.
      */
+    @Override
     Descriptors.Descriptor getDescriptorForType();
 
     /**
@@ -240,27 +254,39 @@ public interface Message extends MessageLite, MessageOrBuilder {
 
     // (From MessageLite.Builder, re-declared here only for return type
     // covariance.)
+    @Override
     Builder mergeFrom(ByteString data) throws InvalidProtocolBufferException;
-    Builder mergeFrom(ByteString data,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
     Builder mergeFrom(byte[] data) throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data, int off, int len)
-                      throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
-    Builder mergeFrom(byte[] data, int off, int len,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
+    Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException;
+
+    @Override
     Builder mergeFrom(InputStream input) throws IOException;
-    Builder mergeFrom(InputStream input,
-                      ExtensionRegistryLite extensionRegistry)
-                      throws IOException;
-    boolean mergeDelimitedFrom(InputStream input)
-                               throws IOException;
-    boolean mergeDelimitedFrom(InputStream input,
-                               ExtensionRegistryLite extensionRegistry)
-                               throws IOException;
+
+    @Override
+    Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
+
+    @Override
+    boolean mergeDelimitedFrom(InputStream input) throws IOException;
+
+    @Override
+    boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException;
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MessageLite.java b/java/core/src/main/java/com/google/protobuf/MessageLite.java
index 798b7943..88f531df 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageLite.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageLite.java
@@ -295,6 +295,27 @@ public interface MessageLite extends MessageLiteOrBuilder {
     Builder mergeFrom(InputStream input,
                       ExtensionRegistryLite extensionRegistry)
                       throws IOException;
+    
+    /**
+     * Merge {@code other} into the message being built.  {@code other} must
+     * have the exact same type as {@code this} (i.e.
+     * {@code getClass().equals(getDefaultInstanceForType().getClass())}).
+     *
+     * Merging occurs as follows.  For each field:<br>
+     * * For singular primitive fields, if the field is set in {@code other},
+     *   then {@code other}'s value overwrites the value in this message.<br>
+     * * For singular message fields, if the field is set in {@code other},
+     *   it is merged into the corresponding sub-message of this message
+     *   using the same merging rules.<br>
+     * * For repeated fields, the elements in {@code other} are concatenated
+     *   with the elements in this message.
+     * * For oneof groups, if the other message has one of the fields set,
+     *   the group of this message is cleared and replaced by the field
+     *   of the other message, so that the oneof constraint is preserved.
+     *
+     * This is equivalent to the {@code Message::MergeFrom} method in C++.
+     */
+    Builder mergeFrom(MessageLite other);
 
     /**
      * Like {@link #mergeFrom(InputStream)}, but does not read until EOF.
diff --git a/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java b/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
index 2a6e0e30..43847651 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageLiteToString.java
@@ -30,23 +30,24 @@
 
 package com.google.protobuf;
 
-import java.lang.reflect.Field;
 import java.lang.reflect.Method;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
+import java.util.TreeSet;
 
 /**
  * Helps generate {@link String} representations of {@link MessageLite} protos.
  */
+// TODO(dweis): Fix map fields.
 final class MessageLiteToString {
-  /**
-   * Suffix for *_FIELD_NUMBER fields. This is used to reflectively detect proto fields that should
-   * be toString()ed.
-   */
-  private static final String FIELD_NUMBER_NAME_SUFFIX = "_FIELD_NUMBER";
 
+  private static final String LIST_SUFFIX = "List";
+  private static final String BUILDER_LIST_SUFFIX = "OrBuilderList";
+  private static final String BYTES_SUFFIX = "Bytes";
+  
   /**
    * Returns a {@link String} representation of the {@link MessageLite} object.  The first line of
    * the {@code String} representation representation includes a comment string to uniquely identify
@@ -73,52 +74,70 @@ final class MessageLiteToString {
     // Build a map of method name to method. We're looking for methods like getFoo(), hasFoo(), and
     // getFooList() which might be useful for building an object's string representation.
     Map<String, Method> nameToNoArgMethod = new HashMap<String, Method>();
+    Map<String, Method> nameToMethod = new HashMap<String, Method>();
+    Set<String> getters = new TreeSet<String>();
     for (Method method : messageLite.getClass().getDeclaredMethods()) {
+      nameToMethod.put(method.getName(), method);
       if (method.getParameterTypes().length == 0) {
         nameToNoArgMethod.put(method.getName(), method);
+
+        if (method.getName().startsWith("get")) {
+          getters.add(method.getName());
+        }
       }
     }
 
-    for (Field field : messageLite.getClass().getDeclaredFields()) {
-      String fieldName = field.getName();
-      // Skip all fields that aren't in a format like "FOO_BAR_FIELD_NUMBER"
-      if (!fieldName.endsWith(FIELD_NUMBER_NAME_SUFFIX)) {
-        continue;
+    for (String getter : getters) {
+      String suffix = getter.replaceFirst("get", "");
+      if (suffix.endsWith(LIST_SUFFIX) && !suffix.endsWith(BUILDER_LIST_SUFFIX)) {
+        String camelCase = suffix.substring(0, 1).toLowerCase()
+            + suffix.substring(1, suffix.length() - LIST_SUFFIX.length());
+        // Try to reflectively get the value and toString() the field as if it were repeated. This
+        // only works if the method names have not be proguarded out or renamed.
+        Method listMethod = nameToNoArgMethod.get("get" + suffix);
+        if (listMethod != null) {
+          printField(
+              buffer,
+              indent,
+              camelCaseToSnakeCase(camelCase),
+              GeneratedMessageLite.invokeOrDie(listMethod, messageLite));
+          continue;
+        }
       }
 
-      // For "FOO_BAR_FIELD_NUMBER" his would be "FOO_BAR"
-      String upperUnderscore =
-          fieldName.substring(0, fieldName.length() - FIELD_NUMBER_NAME_SUFFIX.length());
-
-      // For "FOO_BAR_FIELD_NUMBER" his would be "FooBar"
-      String upperCamelCaseName = upperUnderscoreToUpperCamel(upperUnderscore);
+      Method setter = nameToMethod.get("set" + suffix);
+      if (setter == null) {
+        continue;
+      }
+      if (suffix.endsWith(BYTES_SUFFIX)
+          && nameToNoArgMethod.containsKey(
+              "get" + suffix.substring(0, suffix.length() - "Bytes".length()))) {
+        // Heuristic to skip bytes based accessors for string fields.
+        continue;
+      }
+      
+      String camelCase = suffix.substring(0, 1).toLowerCase() + suffix.substring(1);
 
       // Try to reflectively get the value and toString() the field as if it were optional. This
       // only works if the method names have not be proguarded out or renamed.
-      Method getMethod = nameToNoArgMethod.get("get" + upperCamelCaseName);
-      Method hasMethod = nameToNoArgMethod.get("has" + upperCamelCaseName);
-      if (getMethod != null && hasMethod != null) {
-        if ((Boolean) GeneratedMessageLite.invokeOrDie(hasMethod, messageLite)) {
+      Method getMethod = nameToNoArgMethod.get("get" + suffix);
+      Method hasMethod = nameToNoArgMethod.get("has" + suffix);
+      // TODO(dweis): Fix proto3 semantics.
+      if (getMethod != null) {
+        Object value = GeneratedMessageLite.invokeOrDie(getMethod, messageLite);
+        final boolean hasValue = hasMethod == null
+            ? !isDefaultValue(value)
+            : (Boolean) GeneratedMessageLite.invokeOrDie(hasMethod, messageLite);
+         // TODO(dweis): This doesn't stop printing oneof case twice: value and enum style.
+        if (hasValue) {
           printField(
               buffer,
               indent,
-              upperUnderscore.toLowerCase(),
-              GeneratedMessageLite.invokeOrDie(getMethod, messageLite));
+              camelCaseToSnakeCase(camelCase),
+              value);
         }
         continue;
       }
-
-      // Try to reflectively get the value and toString() the field as if it were repeated. This
-      // only works if the method names have not be proguarded out or renamed.
-      Method listMethod = nameToNoArgMethod.get("get" + upperCamelCaseName + "List");
-      if (listMethod != null) {
-        printField(
-            buffer,
-            indent,
-            upperUnderscore.toLowerCase(),
-            GeneratedMessageLite.invokeOrDie(listMethod, messageLite));
-        continue;
-      }
     }
 
     if (messageLite instanceof GeneratedMessageLite.ExtendableMessage) {
@@ -130,10 +149,39 @@ final class MessageLiteToString {
       }
     }
 
-    if (((GeneratedMessageLite) messageLite).unknownFields != null) {
-      ((GeneratedMessageLite) messageLite).unknownFields.printWithIndent(buffer, indent);
+    if (((GeneratedMessageLite<?, ?>) messageLite).unknownFields != null) {
+      ((GeneratedMessageLite<?, ?>) messageLite).unknownFields.printWithIndent(buffer, indent);
     }
   }
+  
+  private static boolean isDefaultValue(Object o) {
+    if (o instanceof Boolean) {
+      return !((Boolean) o);
+    }
+    if (o instanceof Integer) {
+      return ((Integer) o) == 0;
+    }
+    if (o instanceof Float) {
+      return ((Float) o) == 0f;
+    }
+    if (o instanceof Double) {
+      return ((Double) o) == 0d;
+    }
+    if (o instanceof String) {
+      return o.equals("");
+    }
+    if (o instanceof ByteString) {
+      return o.equals(ByteString.EMPTY);
+    }
+    if (o instanceof MessageLite) { // Can happen in oneofs.
+      return o == ((MessageLite) o).getDefaultInstanceForType();
+    }
+    if (o instanceof java.lang.Enum<?>) { // Catches oneof enums.
+      return ((java.lang.Enum<?>) o).ordinal() == 0;
+    }
+    
+    return false;
+  }
 
   /**
    * Formats a text proto field.
@@ -166,7 +214,7 @@ final class MessageLiteToString {
       buffer.append(": \"").append(TextFormatEscaper.escapeBytes((ByteString) object)).append('"');
     } else if (object instanceof GeneratedMessageLite) {
       buffer.append(" {");
-      reflectivePrintWithIndent((GeneratedMessageLite) object, buffer, indent + 2);
+      reflectivePrintWithIndent((GeneratedMessageLite<?, ?>) object, buffer, indent + 2);
       buffer.append("\n");
       for (int i = 0; i < indent; i++) {
         buffer.append(' ');
@@ -176,25 +224,16 @@ final class MessageLiteToString {
       buffer.append(": ").append(object.toString());
     }
   }
-
-  /**
-   * A Guava-less implementation of:
-   * {@code CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.UPPER_CAMEL, upperUnderscore)}
-   */
-  private static String upperUnderscoreToUpperCamel(String upperUnderscore) {
-    String upperCamelCaseName = "";
-    boolean nextCharacterShouldBeUpper = true;
-    for (int i = 0; i < upperUnderscore.length(); i++) {
-      char ch = upperUnderscore.charAt(i);
-      if (ch == '_') {
-        nextCharacterShouldBeUpper = true;
-      } else if (nextCharacterShouldBeUpper){
-        upperCamelCaseName += Character.toUpperCase(ch);
-        nextCharacterShouldBeUpper = false;
-      } else {
-        upperCamelCaseName += Character.toLowerCase(ch);
+  
+  private static final String camelCaseToSnakeCase(String camelCase) {
+    StringBuilder builder = new StringBuilder();
+    for (int i = 0; i < camelCase.length(); i++) {
+      char ch = camelCase.charAt(i);
+      if (Character.isUpperCase(ch)) {
+        builder.append("_");
       }
+      builder.append(Character.toLowerCase(ch));
     }
-    return upperCamelCaseName;
+    return builder.toString();
   }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java b/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
index f0fc4859..5e7d7821 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageOrBuilder.java
@@ -42,7 +42,7 @@ import java.util.Map;
 public interface MessageOrBuilder extends MessageLiteOrBuilder {
 
   // (From MessageLite, re-declared here only for return type covariance.)
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   Message getDefaultInstanceForType();
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/MessageReflection.java b/java/core/src/main/java/com/google/protobuf/MessageReflection.java
index de4bfd3e..7b791d9e 100644
--- a/java/core/src/main/java/com/google/protobuf/MessageReflection.java
+++ b/java/core/src/main/java/com/google/protobuf/MessageReflection.java
@@ -364,12 +364,14 @@ class MessageReflection {
      * Finishes the merge and returns the underlying object.
      */
     Object finish();
+    
   }
 
   static class BuilderAdapter implements MergeTarget {
 
     private final Message.Builder builder;
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       return builder.getDescriptorForType();
     }
@@ -378,6 +380,7 @@ class MessageReflection {
       this.builder = builder;
     }
 
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return builder.getField(field);
     }
@@ -387,25 +390,27 @@ class MessageReflection {
       return builder.hasField(field);
     }
 
-    public MergeTarget setField(Descriptors.FieldDescriptor field,
-        Object value) {
+    @Override
+    public MergeTarget setField(Descriptors.FieldDescriptor field, Object value) {
       builder.setField(field, value);
       return this;
     }
 
+    @Override
     public MergeTarget clearField(Descriptors.FieldDescriptor field) {
       builder.clearField(field);
       return this;
     }
 
+    @Override
     public MergeTarget setRepeatedField(
         Descriptors.FieldDescriptor field, int index, Object value) {
       builder.setRepeatedField(field, index, value);
       return this;
     }
 
-    public MergeTarget addRepeatedField(
-        Descriptors.FieldDescriptor field, Object value) {
+    @Override
+    public MergeTarget addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
       builder.addRepeatedField(field, value);
       return this;
     }
@@ -426,25 +431,30 @@ class MessageReflection {
       return builder.getOneofFieldDescriptor(oneof);
     }
 
+    @Override
     public ContainerType getContainerType() {
       return ContainerType.MESSAGE;
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByName(
         ExtensionRegistry registry, String name) {
       return registry.findImmutableExtensionByName(name);
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByNumber(
-        ExtensionRegistry registry, Descriptors.Descriptor containingType,
-        int fieldNumber) {
+        ExtensionRegistry registry, Descriptors.Descriptor containingType, int fieldNumber) {
       return registry.findImmutableExtensionByNumber(containingType,
           fieldNumber);
     }
 
-    public Object parseGroup(CodedInputStream input,
+    @Override
+    public Object parseGroup(
+        CodedInputStream input,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -463,9 +473,12 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessage(CodedInputStream input,
+    @Override
+    public Object parseMessage(
+        CodedInputStream input,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -484,9 +497,12 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessageFromBytes(ByteString bytes,
+    @Override
+    public Object parseMessageFromBytes(
+        ByteString bytes,
         ExtensionRegistryLite extensionRegistry,
-        Descriptors.FieldDescriptor field, Message defaultInstance)
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
         throws IOException {
       Message.Builder subBuilder;
       // When default instance is not null. The field is an extension field.
@@ -505,8 +521,9 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public MergeTarget newMergeTargetForField(Descriptors.FieldDescriptor field,
-        Message defaultInstance) {
+    @Override
+    public MergeTarget newMergeTargetForField(
+        Descriptors.FieldDescriptor field, Message defaultInstance) {
       if (defaultInstance != null) {
         return new BuilderAdapter(
             defaultInstance.newBuilderForType());
@@ -515,8 +532,8 @@ class MessageReflection {
       }
     }
 
-    public WireFormat.Utf8Validation
-        getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
+    @Override
+    public WireFormat.Utf8Validation getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
       if (descriptor.needsUtf8Check()) {
         return WireFormat.Utf8Validation.STRICT;
       }
@@ -528,9 +545,11 @@ class MessageReflection {
       return WireFormat.Utf8Validation.LOOSE;
     }
 
+    @Override
     public Object finish() {
       return builder.buildPartial();
     }
+    
   }
 
 
@@ -542,38 +561,43 @@ class MessageReflection {
       this.extensions = extensions;
     }
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       throw new UnsupportedOperationException(
           "getDescriptorForType() called on FieldSet object");
     }
 
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return extensions.getField(field);
     }
 
+    @Override
     public boolean hasField(Descriptors.FieldDescriptor field) {
       return extensions.hasField(field);
     }
 
-    public MergeTarget setField(Descriptors.FieldDescriptor field,
-        Object value) {
+    @Override
+    public MergeTarget setField(Descriptors.FieldDescriptor field, Object value) {
       extensions.setField(field, value);
       return this;
     }
 
+    @Override
     public MergeTarget clearField(Descriptors.FieldDescriptor field) {
       extensions.clearField(field);
       return this;
     }
 
+    @Override
     public MergeTarget setRepeatedField(
         Descriptors.FieldDescriptor field, int index, Object value) {
       extensions.setRepeatedField(field, index, value);
       return this;
     }
 
-    public MergeTarget addRepeatedField(
-        Descriptors.FieldDescriptor field, Object value) {
+    @Override
+    public MergeTarget addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
       extensions.addRepeatedField(field, value);
       return this;
     }
@@ -594,25 +618,31 @@ class MessageReflection {
       return null;
     }
 
+    @Override
     public ContainerType getContainerType() {
       return ContainerType.EXTENSION_SET;
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByName(
         ExtensionRegistry registry, String name) {
       return registry.findImmutableExtensionByName(name);
     }
 
+    @Override
     public ExtensionRegistry.ExtensionInfo findExtensionByNumber(
-        ExtensionRegistry registry, Descriptors.Descriptor containingType,
-        int fieldNumber) {
+        ExtensionRegistry registry, Descriptors.Descriptor containingType, int fieldNumber) {
       return registry.findImmutableExtensionByNumber(containingType,
           fieldNumber);
     }
 
-    public Object parseGroup(CodedInputStream input,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseGroup(
+        CodedInputStream input,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =
           defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
@@ -625,9 +655,13 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessage(CodedInputStream input,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseMessage(
+        CodedInputStream input,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =
           defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
@@ -640,9 +674,13 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
-    public Object parseMessageFromBytes(ByteString bytes,
-        ExtensionRegistryLite registry, Descriptors.FieldDescriptor field,
-        Message defaultInstance) throws IOException {
+    @Override
+    public Object parseMessageFromBytes(
+        ByteString bytes,
+        ExtensionRegistryLite registry,
+        Descriptors.FieldDescriptor field,
+        Message defaultInstance)
+        throws IOException {
       Message.Builder subBuilder =  defaultInstance.newBuilderForType();
       if (!field.isRepeated()) {
         Message originalMessage = (Message) getField(field);
@@ -654,14 +692,15 @@ class MessageReflection {
       return subBuilder.buildPartial();
     }
 
+    @Override
     public MergeTarget newMergeTargetForField(
         Descriptors.FieldDescriptor descriptor, Message defaultInstance) {
       throw new UnsupportedOperationException(
           "newMergeTargetForField() called on FieldSet object");
     }
 
-    public WireFormat.Utf8Validation
-        getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
+    @Override
+    public WireFormat.Utf8Validation getUtf8Validation(Descriptors.FieldDescriptor descriptor) {
       if (descriptor.needsUtf8Check()) {
         return WireFormat.Utf8Validation.STRICT;
       }
@@ -669,10 +708,12 @@ class MessageReflection {
       return WireFormat.Utf8Validation.LOOSE;
     }
 
+    @Override
     public Object finish() {
       throw new UnsupportedOperationException(
           "finish() called on FieldSet object");
     }
+    
   }
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java b/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
index d2f82ac5..81255ec2 100644
--- a/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
+++ b/java/core/src/main/java/com/google/protobuf/ProtobufArrayList.java
@@ -38,7 +38,7 @@ import java.util.List;
 /**
  * Implements {@link ProtobufList} for non-primitive and {@link String} types.
  */
-class ProtobufArrayList<E> extends AbstractProtobufList<E> {
+final class ProtobufArrayList<E> extends AbstractProtobufList<E> {
 
   private static final ProtobufArrayList<Object> EMPTY_LIST = new ProtobufArrayList<Object>();
   static {
@@ -51,17 +51,23 @@ class ProtobufArrayList<E> extends AbstractProtobufList<E> {
   }
   
   private final List<E> list;
-  
+
   ProtobufArrayList() {
-    list = new ArrayList<E>();
+    this(new ArrayList<E>(DEFAULT_CAPACITY));
   }
   
-  ProtobufArrayList(List<E> toCopy) {
-    list = new ArrayList<E>(toCopy);
+  private ProtobufArrayList(List<E> list) {
+    this.list = list;
   }
-  
-  ProtobufArrayList(int capacity) {
-    list = new ArrayList<E>(capacity);
+
+  @Override
+  public ProtobufArrayList<E> mutableCopyWithCapacity(int capacity) {
+    if (capacity < size()) {
+      throw new IllegalArgumentException();
+    }
+    List<E> newList = new ArrayList<E>(capacity);
+    newList.addAll(list);
+    return new ProtobufArrayList<E>(newList);
   }
   
   @Override
diff --git a/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java b/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
index 0c8df989..a596d301 100644
--- a/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
+++ b/java/core/src/main/java/com/google/protobuf/ProtocolMessageEnum.java
@@ -42,6 +42,7 @@ public interface ProtocolMessageEnum extends Internal.EnumLite {
   /**
    * Return the value's numeric value as defined in the .proto file.
    */
+  @Override
   int getNumber();
 
   /**
diff --git a/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java b/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
index f91cdbce..29f567dc 100644
--- a/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/RepeatedFieldBuilder.java
@@ -579,7 +579,7 @@ public class RepeatedFieldBuilder
     }
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void markDirty() {
     onChanged();
   }
@@ -621,10 +621,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public MType get(int index) {
       return builder.getMessage(index);
     }
@@ -654,10 +656,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public BType get(int index) {
       return builder.getBuilder(index);
     }
@@ -687,10 +691,12 @@ public class RepeatedFieldBuilder
       this.builder = builder;
     }
 
+    @Override
     public int size() {
       return this.builder.getCount();
     }
 
+    @Override
     public IType get(int index) {
       return builder.getMessageOrBuilder(index);
     }
diff --git a/java/core/src/main/java/com/google/protobuf/RpcUtil.java b/java/core/src/main/java/com/google/protobuf/RpcUtil.java
index 694b8d13..f7d555ae 100644
--- a/java/core/src/main/java/com/google/protobuf/RpcUtil.java
+++ b/java/core/src/main/java/com/google/protobuf/RpcUtil.java
@@ -71,6 +71,7 @@ public final class RpcUtil {
       final Class<Type> originalClass,
       final Type defaultInstance) {
     return new RpcCallback<Message>() {
+      @Override
       public void run(final Message parameter) {
         Type typedParameter;
         try {
@@ -107,8 +108,9 @@ public final class RpcUtil {
     return new RpcCallback<ParameterType>() {
       private boolean alreadyCalled = false;
 
+      @Override
       public void run(final ParameterType parameter) {
-        synchronized(this) {
+        synchronized (this) {
           if (alreadyCalled) {
             throw new AlreadyCalledException();
           }
diff --git a/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
index aba65e32..941b5def 100644
--- a/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
+++ b/java/core/src/main/java/com/google/protobuf/SingleFieldBuilder.java
@@ -234,7 +234,7 @@ public class SingleFieldBuilder
     }
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void markDirty() {
     onChanged();
   }
diff --git a/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java b/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
index dff19328..409fec10 100644
--- a/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
+++ b/java/core/src/main/java/com/google/protobuf/SmallSortedMap.java
@@ -411,22 +411,22 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
       this.value = value;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public K getKey() {
       return key;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public V getValue() {
       return value;
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public int compareTo(Entry other) {
       return getKey().compareTo(other.getKey());
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public V setValue(V newValue) {
       checkMutable();
       final V oldValue = this.value;
@@ -535,13 +535,13 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
     private boolean nextCalledBeforeRemove;
     private Iterator<Map.Entry<K, V>> lazyOverflowIterator;
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public boolean hasNext() {
       return (pos + 1) < entryList.size() ||
           getOverflowIterator().hasNext();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public Map.Entry<K, V> next() {
       nextCalledBeforeRemove = true;
       // Always increment pos so that we know whether the last returned value
@@ -552,7 +552,7 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
       return getOverflowIterator().next();
     }
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public void remove() {
       if (!nextCalledBeforeRemove) {
         throw new IllegalStateException("remove() was called before next()");
@@ -588,31 +588,83 @@ class SmallSortedMap<K extends Comparable<K>, V> extends AbstractMap<K, V> {
    */
   private static class EmptySet {
 
-    private static final Iterator<Object> ITERATOR = new Iterator<Object>() {
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public boolean hasNext() {
-        return false;
-      }
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public Object next() {
-        throw new NoSuchElementException();
-      }
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public void remove() {
-        throw new UnsupportedOperationException();
-      }
-    };
+    private static final Iterator<Object> ITERATOR =
+        new Iterator<Object>() {
+          @Override
+          public boolean hasNext() {
+            return false;
+          }
+          @Override
+          public Object next() {
+            throw new NoSuchElementException();
+          }
+          @Override
+          public void remove() {
+            throw new UnsupportedOperationException();
+          }
+        };
 
-    private static final Iterable<Object> ITERABLE = new Iterable<Object>() {
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
-      public Iterator<Object> iterator() {
-        return ITERATOR;
-      }
-    };
+    private static final Iterable<Object> ITERABLE =
+        new Iterable<Object>() {
+          @Override
+          public Iterator<Object> iterator() {
+            return ITERATOR;
+          }
+        };
 
     @SuppressWarnings("unchecked")
     static <T> Iterable<T> iterable() {
       return (Iterable<T>) ITERABLE;
     }
   }
+  
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) {
+      return true;
+    }
+    
+    if (!(o instanceof SmallSortedMap)) {
+      return super.equals(o);
+    }
+    
+    SmallSortedMap<?, ?> other = (SmallSortedMap<?, ?>) o;
+    final int size = size();
+    if (size != other.size()) {
+      return false;
+    }
+    
+    // Best effort try to avoid allocating an entry set.
+    final int numArrayEntries = getNumArrayEntries();
+    if (numArrayEntries != other.getNumArrayEntries()) {
+      return entrySet().equals(other.entrySet());
+    }
+    
+    for (int i = 0; i < numArrayEntries; i++) {
+      if (!getArrayEntryAt(i).equals(other.getArrayEntryAt(i))) {
+        return false;
+      }
+    }
+    
+    if (numArrayEntries != size) {
+      return overflowEntries.equals(other.overflowEntries);
+    }
+    
+    
+    return true;
+  }
+  
+  @Override
+  public int hashCode() {
+    int h = 0;
+    final int listSize = getNumArrayEntries();
+    for (int i = 0; i < listSize; i++) {
+      h += entryList.get(i).hashCode();
+    }
+    // Avoid the iterator allocation if possible.
+    if (getNumOverflowEntries() > 0) {
+      h += overflowEntries.hashCode();
+    }
+    return h;
+  }
 }
diff --git a/java/core/src/main/java/com/google/protobuf/TextFormat.java b/java/core/src/main/java/com/google/protobuf/TextFormat.java
index edf114fa..c1c328fc 100644
--- a/java/core/src/main/java/com/google/protobuf/TextFormat.java
+++ b/java/core/src/main/java/com/google/protobuf/TextFormat.java
@@ -965,11 +965,13 @@ public final class TextFormat {
      */
     public boolean consumeBoolean() throws ParseException {
       if (currentToken.equals("true")
+          || currentToken.equals("True")
           || currentToken.equals("t")
           || currentToken.equals("1")) {
         nextToken();
         return true;
       } else if (currentToken.equals("false")
+          || currentToken.equals("False")
           || currentToken.equals("f")
           || currentToken.equals("0")) {
         nextToken();
diff --git a/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java b/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
index 7cd2250e..c906420d 100644
--- a/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
+++ b/java/core/src/main/java/com/google/protobuf/UnknownFieldSet.java
@@ -76,6 +76,7 @@ public final class UnknownFieldSet implements MessageLite {
   public static UnknownFieldSet getDefaultInstance() {
     return defaultInstance;
   }
+  @Override
   public UnknownFieldSet getDefaultInstanceForType() {
     return defaultInstance;
   }
@@ -126,6 +127,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   /** Serializes the set and writes it to {@code output}. */
+  @Override
   public void writeTo(final CodedOutputStream output) throws IOException {
     for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
       entry.getValue().writeTo(entry.getKey(), output);
@@ -146,6 +148,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message to a {@code ByteString} and returns it. This is
    * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public ByteString toByteString() {
     try {
       final ByteString.CodedBuilder out =
@@ -163,6 +166,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message to a {@code byte} array and returns it.  This is
    * just a trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public byte[] toByteArray() {
     try {
       final byte[] result = new byte[getSerializedSize()];
@@ -181,12 +185,14 @@ public final class UnknownFieldSet implements MessageLite {
    * Serializes the message and writes it to {@code output}.  This is just a
    * trivial wrapper around {@link #writeTo(CodedOutputStream)}.
    */
+  @Override
   public void writeTo(final OutputStream output) throws IOException {
     final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
     writeTo(codedOutput);
     codedOutput.flush();
   }
 
+  @Override
   public void writeDelimitedTo(OutputStream output) throws IOException {
     final CodedOutputStream codedOutput = CodedOutputStream.newInstance(output);
     codedOutput.writeRawVarint32(getSerializedSize());
@@ -195,6 +201,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   /** Get the number of bytes required to encode this set. */
+  @Override
   public int getSerializedSize() {
     int result = 0;
     for (final Map.Entry<Integer, Field> entry : fields.entrySet()) {
@@ -228,6 +235,7 @@ public final class UnknownFieldSet implements MessageLite {
     return result;
   }
 
+  @Override
   public boolean isInitialized() {
     // UnknownFieldSets do not have required fields, so they are always
     // initialized.
@@ -258,10 +266,12 @@ public final class UnknownFieldSet implements MessageLite {
     return newBuilder().mergeFrom(input).build();
   }
 
+  @Override
   public Builder newBuilderForType() {
     return newBuilder();
   }
 
+  @Override
   public Builder toBuilder() {
     return newBuilder().mergeFrom(this);
   }
@@ -329,6 +339,7 @@ public final class UnknownFieldSet implements MessageLite {
      * in undefined behavior and can cause a {@code NullPointerException} to be
      * thrown.
      */
+    @Override
     public UnknownFieldSet build() {
       getFieldBuilder(0);  // Force lastField to be built.
       final UnknownFieldSet result;
@@ -341,6 +352,7 @@ public final class UnknownFieldSet implements MessageLite {
       return result;
     }
 
+    @Override
     public UnknownFieldSet buildPartial() {
       // No required fields, so this is the same as build().
       return build();
@@ -353,6 +365,7 @@ public final class UnknownFieldSet implements MessageLite {
           new UnknownFieldSet(fields));
     }
 
+    @Override
     public UnknownFieldSet getDefaultInstanceForType() {
       return UnknownFieldSet.getDefaultInstance();
     }
@@ -364,6 +377,7 @@ public final class UnknownFieldSet implements MessageLite {
     }
 
     /** Reset the builder to an empty set. */
+    @Override
     public Builder clear() {
       reinitialize();
       return this;
@@ -487,6 +501,7 @@ public final class UnknownFieldSet implements MessageLite {
      * Parse an entire message from {@code input} and merge its fields into
      * this set.
      */
+    @Override
     public Builder mergeFrom(final CodedInputStream input) throws IOException {
       while (true) {
         final int tag = input.readTag();
@@ -536,8 +551,8 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
-    public Builder mergeFrom(final ByteString data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = data.newCodedInput();
         mergeFrom(input);
@@ -557,8 +572,8 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
-    public Builder mergeFrom(final byte[] data)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input = CodedInputStream.newInstance(data);
         mergeFrom(input);
@@ -578,6 +593,7 @@ public final class UnknownFieldSet implements MessageLite {
      * set being built.  This is just a small wrapper around
      * {@link #mergeFrom(CodedInputStream)}.
      */
+    @Override
     public Builder mergeFrom(final InputStream input) throws IOException {
       final CodedInputStream codedInput = CodedInputStream.newInstance(input);
       mergeFrom(codedInput);
@@ -585,8 +601,8 @@ public final class UnknownFieldSet implements MessageLite {
       return this;
     }
 
-    public boolean mergeDelimitedFrom(InputStream input)
-        throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(InputStream input) throws IOException {
       final int firstByte = input.read();
       if (firstByte == -1) {
         return false;
@@ -597,30 +613,29 @@ public final class UnknownFieldSet implements MessageLite {
       return true;
     }
 
-    public boolean mergeDelimitedFrom(
-        InputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public boolean mergeDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeDelimitedFrom(input);
     }
 
-    public Builder mergeFrom(
-        CodedInputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public Builder mergeFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(input);
     }
 
-    public Builder mergeFrom(
-        ByteString data,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data);
     }
 
-    public Builder mergeFrom(byte[] data, int off, int len)
-        throws InvalidProtocolBufferException {
+    @Override
+    public Builder mergeFrom(byte[] data, int off, int len) throws InvalidProtocolBufferException {
       try {
         final CodedInputStream input =
             CodedInputStream.newInstance(data, off, len);
@@ -636,29 +651,37 @@ public final class UnknownFieldSet implements MessageLite {
       }
     }
 
-    public Builder mergeFrom(
-        byte[] data,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data);
     }
 
-    public Builder mergeFrom(
-        byte[] data, int off, int len,
-        ExtensionRegistryLite extensionRegistry)
+    @Override
+    public Builder mergeFrom(byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(data, off, len);
     }
 
-    public Builder mergeFrom(
-        InputStream input,
-        ExtensionRegistryLite extensionRegistry) throws IOException {
+    @Override
+    public Builder mergeFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+        throws IOException {
       // UnknownFieldSet has no extensions.
       return mergeFrom(input);
     }
 
+    @Override
+    public Builder mergeFrom(MessageLite m) {
+      if (m instanceof UnknownFieldSet) {
+        return mergeFrom((UnknownFieldSet) m);
+      }
+      throw new IllegalArgumentException(
+          "mergeFrom(MessageLite) can only merge messages of the same type.");
+    }
+
+    @Override
     public boolean isInitialized() {
       // UnknownFieldSets do not have required fields, so they are always
       // initialized.
@@ -987,6 +1010,7 @@ public final class UnknownFieldSet implements MessageLite {
    * Parser to implement MessageLite interface.
    */
   public static final class Parser extends AbstractParser<UnknownFieldSet> {
+    @Override
     public UnknownFieldSet parsePartialFrom(
         CodedInputStream input, ExtensionRegistryLite extensionRegistry)
         throws InvalidProtocolBufferException {
@@ -1004,6 +1028,7 @@ public final class UnknownFieldSet implements MessageLite {
   }
 
   private static final Parser PARSER = new Parser();
+  @Override
   public final Parser getParserForType() {
     return PARSER;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java b/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
index 5257c5a2..30e87911 100644
--- a/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
+++ b/java/core/src/main/java/com/google/protobuf/UnmodifiableLazyStringList.java
@@ -68,42 +68,42 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return list.size();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public ByteString getByteString(int index) {
     return list.getByteString(index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void add(ByteString element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void set(int index, ByteString element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean addAllByteString(Collection<? extends ByteString> element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public byte[] getByteArray(int index) {
     return list.getByteArray(index);
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void add(byte[] element) {
     throw new UnsupportedOperationException();
   }
   
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void set(int index, byte[] element) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public boolean addAllByteArray(Collection<byte[]> element) {
     throw new UnsupportedOperationException();
   }
@@ -113,47 +113,47 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return new ListIterator<String>() {
       ListIterator<String> iter = list.listIterator(index);
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasNext() {
         return iter.hasNext();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String next() {
         return iter.next();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasPrevious() {
         return iter.hasPrevious();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String previous() {
         return iter.previous();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public int nextIndex() {
         return iter.nextIndex();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public int previousIndex() {
         return iter.previousIndex();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void remove() {
         throw new UnsupportedOperationException();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void set(String o) {
         throw new UnsupportedOperationException();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void add(String o) {
         throw new UnsupportedOperationException();
       }
@@ -165,45 +165,45 @@ public class UnmodifiableLazyStringList extends AbstractList<String>
     return new Iterator<String>() {
       Iterator<String> iter = list.iterator();
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public boolean hasNext() {
         return iter.hasNext();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public String next() {
         return iter.next();
       }
 
-      //@Override (Java 1.6 override semantics, but we must support 1.5)
+      @Override
       public void remove() {
         throw new UnsupportedOperationException();
       }
     };
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<?> getUnderlyingElements() {
     // The returned value is already unmodifiable.
     return list.getUnderlyingElements();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void mergeFrom(LazyStringList other) {
     throw new UnsupportedOperationException();
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<byte[]> asByteArrayList() {
     return Collections.unmodifiableList(list.asByteArrayList());
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public List<ByteString> asByteStringList() {
     return Collections.unmodifiableList(list.asByteStringList());
   }
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public LazyStringList getUnmodifiableView() {
     return this;
   }
diff --git a/java/core/src/main/java/com/google/protobuf/WireFormat.java b/java/core/src/main/java/com/google/protobuf/WireFormat.java
index 8dbe1ae3..6a58b081 100644
--- a/java/core/src/main/java/com/google/protobuf/WireFormat.java
+++ b/java/core/src/main/java/com/google/protobuf/WireFormat.java
@@ -116,16 +116,24 @@ public final class WireFormat {
     FIXED32 (JavaType.INT        , WIRETYPE_FIXED32         ),
     BOOL    (JavaType.BOOLEAN    , WIRETYPE_VARINT          ),
     STRING  (JavaType.STRING     , WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     GROUP   (JavaType.MESSAGE    , WIRETYPE_START_GROUP     ) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     MESSAGE (JavaType.MESSAGE    , WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     BYTES   (JavaType.BYTE_STRING, WIRETYPE_LENGTH_DELIMITED) {
-      public boolean isPackable() { return false; }
+      @Override
+      public boolean isPackable() {
+        return false; }
     },
     UINT32  (JavaType.INT        , WIRETYPE_VARINT          ),
     ENUM    (JavaType.ENUM       , WIRETYPE_VARINT          ),
@@ -170,18 +178,21 @@ public final class WireFormat {
   enum Utf8Validation {
     /** Eagerly parses to String; silently accepts invalid UTF8 bytes. */
     LOOSE {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readString();
       }
     },
     /** Eagerly parses to String; throws an IOException on invalid bytes. */
     STRICT {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readStringRequireUtf8();
       }
     },
     /** Keep data as ByteString; validation/conversion to String is lazy. */
     LAZY {
+      @Override
       Object readString(CodedInputStream input) throws IOException {
         return input.readBytes();
       }
diff --git a/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java b/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
index 1e57b647..7dc9fc15 100644
--- a/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/AbstractMessageTest.java
@@ -64,35 +64,44 @@ public class AbstractMessageTest extends TestCase {
       this.wrappedMessage = wrappedMessage;
     }
 
+    @Override
     public Descriptors.Descriptor getDescriptorForType() {
       return wrappedMessage.getDescriptorForType();
     }
+    @Override
     public AbstractMessageWrapper getDefaultInstanceForType() {
       return new AbstractMessageWrapper(
         wrappedMessage.getDefaultInstanceForType());
     }
+    @Override
     public Map<Descriptors.FieldDescriptor, Object> getAllFields() {
       return wrappedMessage.getAllFields();
     }
+    @Override
     public boolean hasField(Descriptors.FieldDescriptor field) {
       return wrappedMessage.hasField(field);
     }
+    @Override
     public Object getField(Descriptors.FieldDescriptor field) {
       return wrappedMessage.getField(field);
     }
+    @Override
     public int getRepeatedFieldCount(Descriptors.FieldDescriptor field) {
       return wrappedMessage.getRepeatedFieldCount(field);
     }
-    public Object getRepeatedField(
-        Descriptors.FieldDescriptor field, int index) {
+    @Override
+    public Object getRepeatedField(Descriptors.FieldDescriptor field, int index) {
       return wrappedMessage.getRepeatedField(field, index);
     }
+    @Override
     public UnknownFieldSet getUnknownFields() {
       return wrappedMessage.getUnknownFields();
     }
+    @Override
     public Builder newBuilderForType() {
       return new Builder(wrappedMessage.newBuilderForType());
     }
+    @Override
     public Builder toBuilder() {
       return new Builder(wrappedMessage.toBuilder());
     }
@@ -104,65 +113,80 @@ public class AbstractMessageTest extends TestCase {
         this.wrappedBuilder = wrappedBuilder;
       }
 
+      @Override
       public AbstractMessageWrapper build() {
         return new AbstractMessageWrapper(wrappedBuilder.build());
       }
+      @Override
       public AbstractMessageWrapper buildPartial() {
         return new AbstractMessageWrapper(wrappedBuilder.buildPartial());
       }
+      @Override
       public Builder clone() {
         return new Builder(wrappedBuilder.clone());
       }
+      @Override
       public boolean isInitialized() {
         return clone().buildPartial().isInitialized();
       }
+      @Override
       public Descriptors.Descriptor getDescriptorForType() {
         return wrappedBuilder.getDescriptorForType();
       }
+      @Override
       public AbstractMessageWrapper getDefaultInstanceForType() {
         return new AbstractMessageWrapper(
           wrappedBuilder.getDefaultInstanceForType());
       }
+      @Override
       public Map<Descriptors.FieldDescriptor, Object> getAllFields() {
         return wrappedBuilder.getAllFields();
       }
+      @Override
       public Builder newBuilderForField(Descriptors.FieldDescriptor field) {
         return new Builder(wrappedBuilder.newBuilderForField(field));
       }
+      @Override
       public boolean hasField(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.hasField(field);
       }
+      @Override
       public Object getField(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.getField(field);
       }
+      @Override
       public Builder setField(Descriptors.FieldDescriptor field, Object value) {
         wrappedBuilder.setField(field, value);
         return this;
       }
+      @Override
       public Builder clearField(Descriptors.FieldDescriptor field) {
         wrappedBuilder.clearField(field);
         return this;
       }
+      @Override
       public int getRepeatedFieldCount(Descriptors.FieldDescriptor field) {
         return wrappedBuilder.getRepeatedFieldCount(field);
       }
-      public Object getRepeatedField(
-          Descriptors.FieldDescriptor field, int index) {
+      @Override
+      public Object getRepeatedField(Descriptors.FieldDescriptor field, int index) {
         return wrappedBuilder.getRepeatedField(field, index);
       }
-      public Builder setRepeatedField(Descriptors.FieldDescriptor field,
-                                      int index, Object value) {
+      @Override
+      public Builder setRepeatedField(Descriptors.FieldDescriptor field, int index, Object value) {
         wrappedBuilder.setRepeatedField(field, index, value);
         return this;
       }
-      public Builder addRepeatedField(
-          Descriptors.FieldDescriptor field, Object value) {
+      @Override
+      public Builder addRepeatedField(Descriptors.FieldDescriptor field, Object value) {
         wrappedBuilder.addRepeatedField(field, value);
         return this;
       }
+      @Override
       public UnknownFieldSet getUnknownFields() {
         return wrappedBuilder.getUnknownFields();
       }
+      @Override
       public Builder setUnknownFields(UnknownFieldSet unknownFields) {
         wrappedBuilder.setUnknownFields(unknownFields);
         return this;
@@ -172,6 +196,7 @@ public class AbstractMessageTest extends TestCase {
         return wrappedBuilder.getFieldBuilder(field);
       }
     }
+    @Override
     public Parser<? extends Message> getParserForType() {
       return wrappedMessage.getParserForType();
     }
diff --git a/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java b/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
index b8ad1fe4..24b96c60 100644
--- a/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/BooleanArrayListTest.java
@@ -73,20 +73,6 @@ public class BooleanArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    BooleanArrayList copy = new BooleanArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new BooleanArrayList(BooleanArrayList.emptyList());
-    assertEquals(BooleanArrayList.emptyList(), copy);
-    
-    copy = new BooleanArrayList(asList(false, false, true));
-    assertEquals(asList(false, false, true), copy);
-
-    copy = new BooleanArrayList(Collections.<Boolean>emptyList());
-    assertEquals(BooleanArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(true, false, false, true));
     Iterator<Boolean> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java b/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
index a1d6f1be..ca940ced 100644
--- a/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
+++ b/java/core/src/test/java/com/google/protobuf/CodedInputStreamTest.java
@@ -81,10 +81,12 @@ public class CodedInputStreamTest extends TestCase {
       this.blockSize = blockSize;
     }
 
+    @Override
     public int read(byte[] b) throws IOException {
       return super.read(b, 0, Math.min(b.length, blockSize));
     }
 
+    @Override
     public int read(byte[] b, int off, int len) throws IOException {
       return super.read(b, off, Math.min(len, blockSize));
     }
diff --git a/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java b/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
index 6018ea55..33aa4357 100644
--- a/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
+++ b/java/core/src/test/java/com/google/protobuf/CodedOutputStreamTest.java
@@ -30,6 +30,7 @@
 
 package com.google.protobuf;
 
+import com.google.protobuf.CodedOutputStream.OutOfSpaceException;
 import protobuf_unittest.UnittestProto.SparseEnumMessage;
 import protobuf_unittest.UnittestProto.TestAllTypes;
 import protobuf_unittest.UnittestProto.TestPackedTypes;
@@ -50,118 +51,180 @@ import java.util.List;
  * @author kenton@google.com Kenton Varda
  */
 public class CodedOutputStreamTest extends TestCase {
-  /**
-   * Helper to construct a byte array from a bunch of bytes.  The inputs are
-   * actually ints so that I can use hex notation and not get stupid errors
-   * about precision.
-   */
-  private byte[] bytes(int... bytesAsInts) {
-    byte[] bytes = new byte[bytesAsInts.length];
-    for (int i = 0; i < bytesAsInts.length; i++) {
-      bytes[i] = (byte) bytesAsInts[i];
-    }
-    return bytes;
+  private interface Coder {
+    CodedOutputStream stream();
+
+    byte[] toByteArray();
+
+    OutputType getOutputType();
   }
 
-  /** Arrays.asList() does not work with arrays of primitives.  :( */
-  private List<Byte> toList(byte[] bytes) {
-    List<Byte> result = new ArrayList<Byte>();
-    for (byte b : bytes) {
-      result.add(b);
+  private static final class OutputStreamCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final ByteArrayOutputStream output;
+
+    OutputStreamCoder(int size) {
+      output = new ByteArrayOutputStream();
+      stream = CodedOutputStream.newInstance(output, size);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      return output.toByteArray();
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.STREAM;
     }
-    return result;
   }
 
-  private void assertEqualBytes(byte[] a, byte[] b) {
-    assertEquals(toList(a), toList(b));
+  private static final class ArrayCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final byte[] bytes;
+
+    ArrayCoder(int size) {
+      bytes = new byte[size];
+      stream = CodedOutputStream.newInstance(bytes);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      return Arrays.copyOf(bytes, stream.getTotalBytesWritten());
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.ARRAY;
+    }
   }
 
-  /**
-   * Writes the given value using writeRawVarint32() and writeRawVarint64() and
-   * checks that the result matches the given bytes.
-   */
-  private void assertWriteVarint(byte[] data, long value) throws Exception {
-    // Only test 32-bit write if the value fits into an int.
-    if (value == (int) value) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint32((int) value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
+  private static final class NioHeapCoder implements Coder {
+    private final CodedOutputStream stream;
+    private final ByteBuffer buffer;
+    private final int initialPosition;
 
-      // Also try computing size.
-      assertEquals(data.length,
-                   CodedOutputStream.computeRawVarint32Size((int) value));
+    NioHeapCoder(int size) {
+      this(size, 0);
     }
 
-    {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint64(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
+    NioHeapCoder(int size, int initialPosition) {
+      this.initialPosition = initialPosition;
+      buffer = ByteBuffer.allocate(size);
+      buffer.position(initialPosition);
+      stream = CodedOutputStream.newInstance(buffer);
+    }
 
-      // Also try computing size.
-      assertEquals(data.length,
-                   CodedOutputStream.computeRawVarint64Size(value));
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
     }
 
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      // Only test 32-bit write if the value fits into an int.
-      if (value == (int) value) {
-        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-        CodedOutputStream output =
-          CodedOutputStream.newInstance(rawOutput, blockSize);
-        output.writeRawVarint32((int) value);
-        output.flush();
-        assertEqualBytes(data, rawOutput.toByteArray());
-      }
+    @Override
+    public byte[] toByteArray() {
+      ByteBuffer dup = buffer.duplicate();
+      dup.position(initialPosition);
+      dup.limit(buffer.position());
 
-      {
-        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-        CodedOutputStream output =
-          CodedOutputStream.newInstance(rawOutput, blockSize);
-        output.writeRawVarint64(value);
-        output.flush();
-        assertEqualBytes(data, rawOutput.toByteArray());
-      }
+      byte[] bytes = new byte[dup.remaining()];
+      dup.get(bytes);
+      return bytes;
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.NIO_HEAP;
     }
   }
 
-  private void assertVarintRoundTrip(long value) throws Exception {
-    {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint64(value);
-      output.flush();
-      byte[] bytes = rawOutput.toByteArray();
-      assertEquals(bytes.length, CodedOutputStream.computeRawVarint64Size(value));
-      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
-      assertEquals(value, input.readRawVarint64());
+  private static final class NioDirectCoder implements Coder {
+    private final int initialPosition;
+    private final CodedOutputStream stream;
+    private final ByteBuffer buffer;
+
+    NioDirectCoder(int size) {
+      this(size, 0);
     }
 
-    if (value == (int) value) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-      output.writeRawVarint32((int) value);
-      output.flush();
-      byte[] bytes = rawOutput.toByteArray();
-      assertEquals(bytes.length, CodedOutputStream.computeRawVarint32Size((int) value));
-      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
-      assertEquals(value, input.readRawVarint32());
+    NioDirectCoder(int size, int initialPosition) {
+      this.initialPosition = initialPosition;
+      buffer = ByteBuffer.allocateDirect(size);
+      buffer.position(initialPosition);
+      stream = CodedOutputStream.newInstance(buffer);
+    }
+
+    @Override
+    public CodedOutputStream stream() {
+      return stream;
+    }
+
+    @Override
+    public byte[] toByteArray() {
+      ByteBuffer dup = buffer.duplicate();
+      dup.position(initialPosition);
+      dup.limit(buffer.position());
+
+      byte[] bytes = new byte[dup.remaining()];
+      dup.get(bytes);
+      return bytes;
+    }
+
+    @Override
+    public OutputType getOutputType() {
+      return OutputType.NIO_DIRECT;
     }
   }
 
+  private enum OutputType {
+    ARRAY() {
+      @Override
+      Coder newCoder(int size) {
+        return new ArrayCoder(size);
+      }
+    },
+    NIO_HEAP() {
+      @Override
+      Coder newCoder(int size) {
+        return new NioHeapCoder(size);
+      }
+    },
+    NIO_DIRECT() {
+      @Override
+      Coder newCoder(int size) {
+        return new NioDirectCoder(size);
+      }
+    },
+    STREAM() {
+      @Override
+      Coder newCoder(int size) {
+        return new OutputStreamCoder(size);
+      }
+    };
+
+    abstract Coder newCoder(int size);
+  }
+
   /** Checks that invariants are maintained for varint round trip input and output. */
   public void testVarintRoundTrips() throws Exception {
-    assertVarintRoundTrip(0L);
-    for (int bits = 0; bits < 64; bits++) {
-      long value = 1L << bits;
-      assertVarintRoundTrip(value);
-      assertVarintRoundTrip(value + 1);
-      assertVarintRoundTrip(value - 1);
-      assertVarintRoundTrip(-value);
+    for (OutputType outputType : OutputType.values()) {
+      assertVarintRoundTrip(outputType, 0L);
+      for (int bits = 0; bits < 64; bits++) {
+        long value = 1L << bits;
+        assertVarintRoundTrip(outputType, value);
+        assertVarintRoundTrip(outputType, value + 1);
+        assertVarintRoundTrip(outputType, value - 1);
+        assertVarintRoundTrip(outputType, -value);
+      }
     }
   }
 
@@ -173,70 +236,25 @@ public class CodedOutputStreamTest extends TestCase {
     // 14882
     assertWriteVarint(bytes(0xa2, 0x74), (0x22 << 0) | (0x74 << 7));
     // 2961488830
-    assertWriteVarint(bytes(0xbe, 0xf7, 0x92, 0x84, 0x0b),
-      (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
-      (0x0bL << 28));
+    assertWriteVarint(
+        bytes(0xbe, 0xf7, 0x92, 0x84, 0x0b),
+        (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) | (0x0bL << 28));
 
     // 64-bit
     // 7256456126
-    assertWriteVarint(bytes(0xbe, 0xf7, 0x92, 0x84, 0x1b),
-      (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) |
-      (0x1bL << 28));
+    assertWriteVarint(
+        bytes(0xbe, 0xf7, 0x92, 0x84, 0x1b),
+        (0x3e << 0) | (0x77 << 7) | (0x12 << 14) | (0x04 << 21) | (0x1bL << 28));
     // 41256202580718336
     assertWriteVarint(
-      bytes(0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49),
-      (0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) |
-      (0x43L << 28) | (0x49L << 35) | (0x24L << 42) | (0x49L << 49));
+        bytes(0x80, 0xe6, 0xeb, 0x9c, 0xc3, 0xc9, 0xa4, 0x49),
+        (0x00 << 0) | (0x66 << 7) | (0x6b << 14) | (0x1c << 21) | (0x43L << 28) | (0x49L << 35)
+        | (0x24L << 42) | (0x49L << 49));
     // 11964378330978735131
     assertWriteVarint(
-      bytes(0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01),
-      (0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) |
-      (0x3bL << 28) | (0x56L << 35) | (0x00L << 42) |
-      (0x05L << 49) | (0x26L << 56) | (0x01L << 63));
-  }
-
-  /**
-   * Parses the given bytes using writeRawLittleEndian32() and checks
-   * that the result matches the given value.
-   */
-  private void assertWriteLittleEndian32(byte[] data, int value)
-                                         throws Exception {
-    ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-    output.writeRawLittleEndian32(value);
-    output.flush();
-    assertEqualBytes(data, rawOutput.toByteArray());
-
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      rawOutput = new ByteArrayOutputStream();
-      output = CodedOutputStream.newInstance(rawOutput, blockSize);
-      output.writeRawLittleEndian32(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
-    }
-  }
-
-  /**
-   * Parses the given bytes using writeRawLittleEndian64() and checks
-   * that the result matches the given value.
-   */
-  private void assertWriteLittleEndian64(byte[] data, long value)
-                                         throws Exception {
-    ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-    CodedOutputStream output = CodedOutputStream.newInstance(rawOutput);
-    output.writeRawLittleEndian64(value);
-    output.flush();
-    assertEqualBytes(data, rawOutput.toByteArray());
-
-    // Try different block sizes.
-    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
-      rawOutput = new ByteArrayOutputStream();
-      output = CodedOutputStream.newInstance(rawOutput, blockSize);
-      output.writeRawLittleEndian64(value);
-      output.flush();
-      assertEqualBytes(data, rawOutput.toByteArray());
-    }
+        bytes(0x9b, 0xa8, 0xf9, 0xc2, 0xbb, 0xd6, 0x80, 0x85, 0xa6, 0x01),
+        (0x1b << 0) | (0x28 << 7) | (0x79 << 14) | (0x42 << 21) | (0x3bL << 28) | (0x56L << 35)
+        | (0x00L << 42) | (0x05L << 49) | (0x26L << 56) | (0x01L << 63));
   }
 
   /** Tests writeRawLittleEndian32() and writeRawLittleEndian64(). */
@@ -245,141 +263,138 @@ public class CodedOutputStreamTest extends TestCase {
     assertWriteLittleEndian32(bytes(0xf0, 0xde, 0xbc, 0x9a), 0x9abcdef0);
 
     assertWriteLittleEndian64(
-      bytes(0xf0, 0xde, 0xbc, 0x9a, 0x78, 0x56, 0x34, 0x12),
-      0x123456789abcdef0L);
+        bytes(0xf0, 0xde, 0xbc, 0x9a, 0x78, 0x56, 0x34, 0x12), 0x123456789abcdef0L);
     assertWriteLittleEndian64(
-      bytes(0x78, 0x56, 0x34, 0x12, 0xf0, 0xde, 0xbc, 0x9a),
-      0x9abcdef012345678L);
+        bytes(0x78, 0x56, 0x34, 0x12, 0xf0, 0xde, 0xbc, 0x9a), 0x9abcdef012345678L);
   }
 
   /** Test encodeZigZag32() and encodeZigZag64(). */
   public void testEncodeZigZag() throws Exception {
-    assertEquals(0, CodedOutputStream.encodeZigZag32( 0));
+    assertEquals(0, CodedOutputStream.encodeZigZag32(0));
     assertEquals(1, CodedOutputStream.encodeZigZag32(-1));
-    assertEquals(2, CodedOutputStream.encodeZigZag32( 1));
+    assertEquals(2, CodedOutputStream.encodeZigZag32(1));
     assertEquals(3, CodedOutputStream.encodeZigZag32(-2));
     assertEquals(0x7FFFFFFE, CodedOutputStream.encodeZigZag32(0x3FFFFFFF));
     assertEquals(0x7FFFFFFF, CodedOutputStream.encodeZigZag32(0xC0000000));
     assertEquals(0xFFFFFFFE, CodedOutputStream.encodeZigZag32(0x7FFFFFFF));
     assertEquals(0xFFFFFFFF, CodedOutputStream.encodeZigZag32(0x80000000));
 
-    assertEquals(0, CodedOutputStream.encodeZigZag64( 0));
+    assertEquals(0, CodedOutputStream.encodeZigZag64(0));
     assertEquals(1, CodedOutputStream.encodeZigZag64(-1));
-    assertEquals(2, CodedOutputStream.encodeZigZag64( 1));
+    assertEquals(2, CodedOutputStream.encodeZigZag64(1));
     assertEquals(3, CodedOutputStream.encodeZigZag64(-2));
-    assertEquals(0x000000007FFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x000000003FFFFFFFL));
-    assertEquals(0x000000007FFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0xFFFFFFFFC0000000L));
-    assertEquals(0x00000000FFFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x000000007FFFFFFFL));
-    assertEquals(0x00000000FFFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0xFFFFFFFF80000000L));
-    assertEquals(0xFFFFFFFFFFFFFFFEL,
-                 CodedOutputStream.encodeZigZag64(0x7FFFFFFFFFFFFFFFL));
-    assertEquals(0xFFFFFFFFFFFFFFFFL,
-                 CodedOutputStream.encodeZigZag64(0x8000000000000000L));
+    assertEquals(0x000000007FFFFFFEL, CodedOutputStream.encodeZigZag64(0x000000003FFFFFFFL));
+    assertEquals(0x000000007FFFFFFFL, CodedOutputStream.encodeZigZag64(0xFFFFFFFFC0000000L));
+    assertEquals(0x00000000FFFFFFFEL, CodedOutputStream.encodeZigZag64(0x000000007FFFFFFFL));
+    assertEquals(0x00000000FFFFFFFFL, CodedOutputStream.encodeZigZag64(0xFFFFFFFF80000000L));
+    assertEquals(0xFFFFFFFFFFFFFFFEL, CodedOutputStream.encodeZigZag64(0x7FFFFFFFFFFFFFFFL));
+    assertEquals(0xFFFFFFFFFFFFFFFFL, CodedOutputStream.encodeZigZag64(0x8000000000000000L));
 
     // Some easier-to-verify round-trip tests.  The inputs (other than 0, 1, -1)
     // were chosen semi-randomly via keyboard bashing.
-    assertEquals(0,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(0)));
-    assertEquals(1,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(1)));
-    assertEquals(-1,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-1)));
-    assertEquals(14927,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(14927)));
-    assertEquals(-3612,
-      CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-3612)));
-
-    assertEquals(0,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(0)));
-    assertEquals(1,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(1)));
-    assertEquals(-1,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-1)));
-    assertEquals(14927,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(14927)));
-    assertEquals(-3612,
-      CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-3612)));
-
-    assertEquals(856912304801416L,
-      CodedOutputStream.encodeZigZag64(
-        CodedInputStream.decodeZigZag64(
-          856912304801416L)));
-    assertEquals(-75123905439571256L,
-      CodedOutputStream.encodeZigZag64(
-        CodedInputStream.decodeZigZag64(
-          -75123905439571256L)));
+    assertEquals(0, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(0)));
+    assertEquals(1, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(1)));
+    assertEquals(-1, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-1)));
+    assertEquals(14927, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(14927)));
+    assertEquals(-3612, CodedOutputStream.encodeZigZag32(CodedInputStream.decodeZigZag32(-3612)));
+
+    assertEquals(0, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(0)));
+    assertEquals(1, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(1)));
+    assertEquals(-1, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-1)));
+    assertEquals(14927, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(14927)));
+    assertEquals(-3612, CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-3612)));
+
+    assertEquals(
+        856912304801416L,
+        CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(856912304801416L)));
+    assertEquals(
+        -75123905439571256L,
+        CodedOutputStream.encodeZigZag64(CodedInputStream.decodeZigZag64(-75123905439571256L)));
   }
 
   /** Tests writing a whole message with every field type. */
   public void testWriteWholeMessage() throws Exception {
+    final byte[] expectedBytes = TestUtil.getGoldenMessage().toByteArray();
     TestAllTypes message = TestUtil.getAllSet();
 
-    byte[] rawBytes = message.toByteArray();
-    assertEqualBytes(TestUtil.getGoldenMessage().toByteArray(), rawBytes);
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      assertEqualBytes(outputType, expectedBytes, rawBytes);
+    }
 
     // Try different block sizes.
     for (int blockSize = 1; blockSize < 256; blockSize *= 2) {
-      ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
-      CodedOutputStream output =
-        CodedOutputStream.newInstance(rawOutput, blockSize);
-      message.writeTo(output);
-      output.flush();
-      assertEqualBytes(rawBytes, rawOutput.toByteArray());
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, expectedBytes, coder.toByteArray());
     }
   }
 
-  /** Tests writing a whole message with every packed field type. Ensures the
-   * wire format of packed fields is compatible with C++. */
+  /**
+   * Tests writing a whole message with every packed field type. Ensures the
+   * wire format of packed fields is compatible with C++.
+   */
   public void testWriteWholePackedFieldsMessage() throws Exception {
+    byte[] expectedBytes = TestUtil.getGoldenPackedFieldsMessage().toByteArray();
     TestPackedTypes message = TestUtil.getPackedSet();
 
-    byte[] rawBytes = message.toByteArray();
-    assertEqualBytes(TestUtil.getGoldenPackedFieldsMessage().toByteArray(),
-                     rawBytes);
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      assertEqualBytes(outputType, expectedBytes, rawBytes);
+    }
   }
 
-  /** Test writing a message containing a negative enum value. This used to
+  /**
+   * Test writing a message containing a negative enum value. This used to
    * fail because the size was not properly computed as a sign-extended varint.
    */
   public void testWriteMessageWithNegativeEnumValue() throws Exception {
-    SparseEnumMessage message = SparseEnumMessage.newBuilder()
-        .setSparseEnum(TestSparseEnum.SPARSE_E) .build();
+    SparseEnumMessage message =
+        SparseEnumMessage.newBuilder().setSparseEnum(TestSparseEnum.SPARSE_E).build();
     assertTrue(message.getSparseEnum().getNumber() < 0);
-    byte[] rawBytes = message.toByteArray();
-    SparseEnumMessage message2 = SparseEnumMessage.parseFrom(rawBytes);
-    assertEquals(TestSparseEnum.SPARSE_E, message2.getSparseEnum());
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(message.getSerializedSize());
+      message.writeTo(coder.stream());
+      coder.stream().flush();
+      byte[] rawBytes = coder.toByteArray();
+      SparseEnumMessage message2 = SparseEnumMessage.parseFrom(rawBytes);
+      assertEquals(TestSparseEnum.SPARSE_E, message2.getSparseEnum());
+    }
   }
 
   /** Test getTotalBytesWritten() */
   public void testGetTotalBytesWritten() throws Exception {
-    final int BUFFER_SIZE = 4 * 1024;
-    ByteArrayOutputStream outputStream = new ByteArrayOutputStream(BUFFER_SIZE);
-    CodedOutputStream codedStream = CodedOutputStream.newInstance(outputStream);
+    Coder coder = OutputType.STREAM.newCoder(4 * 1024);
+
+    // Write some some bytes (more than the buffer can hold) and verify that totalWritten
+    // is correct.
     byte[] value = "abcde".getBytes(Internal.UTF_8);
     for (int i = 0; i < 1024; ++i) {
-      codedStream.writeRawBytes(value, 0, value.length);
+      coder.stream().writeRawBytes(value, 0, value.length);
     }
+    assertEquals(value.length * 1024, coder.stream().getTotalBytesWritten());
+
+    // Now write an encoded string.
     String string =
         "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";
     // Ensure we take the slower fast path.
-    assertTrue(CodedOutputStream.computeRawVarint32Size(string.length())
-        != CodedOutputStream.computeRawVarint32Size(string.length() * Utf8.MAX_BYTES_PER_CHAR));
-    
-    codedStream.writeStringNoTag(string);
+    assertTrue(CodedOutputStream.computeUInt32SizeNoTag(string.length())
+        != CodedOutputStream.computeUInt32SizeNoTag(string.length() * Utf8.MAX_BYTES_PER_CHAR));
+
+    coder.stream().writeStringNoTag(string);
     int stringSize = CodedOutputStream.computeStringSizeNoTag(string);
-    
-    // Make sure we have written more bytes than the buffer could hold. This is
-    // to make the test complete.
-    assertTrue(codedStream.getTotalBytesWritten() > BUFFER_SIZE);
-    
+
     // Verify that the total bytes written is correct
-    assertEquals((value.length * 1024) + stringSize, codedStream.getTotalBytesWritten());
+    assertEquals((value.length * 1024) + stringSize, coder.stream().getTotalBytesWritten());
   }
-  
+
   // TODO(dweis): Write a comprehensive test suite for CodedOutputStream that covers more than just
   //    this case.
   public void testWriteStringNoTag_fastpath() throws Exception {
@@ -390,14 +405,16 @@ public class CodedOutputStreamTest extends TestCase {
       string += threeBytesPer;
     }
     // These checks ensure we will tickle the slower fast path.
-    assertEquals(1, CodedOutputStream.computeRawVarint32Size(string.length()));
+    assertEquals(1, CodedOutputStream.computeUInt32SizeNoTag(string.length()));
     assertEquals(
-        2, CodedOutputStream.computeRawVarint32Size(string.length() * Utf8.MAX_BYTES_PER_CHAR));
+        2, CodedOutputStream.computeUInt32SizeNoTag(string.length() * Utf8.MAX_BYTES_PER_CHAR));
     assertEquals(bufferSize, string.length() * Utf8.MAX_BYTES_PER_CHAR);
-    
-    CodedOutputStream output =
-        CodedOutputStream.newInstance(ByteBuffer.allocate(bufferSize), bufferSize);
-    output.writeStringNoTag(string);
+
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(bufferSize + 2);
+      coder.stream().writeStringNoTag(string);
+      coder.stream().flush();
+    }
   }
 
   public void testWriteToByteBuffer() throws Exception {
@@ -464,83 +481,296 @@ public class CodedOutputStreamTest extends TestCase {
     byte[] destination = new byte[4];
     CodedOutputStream codedStream = CodedOutputStream.newInstance(destination);
     codedStream.writeByteArrayNoTag(fullArray, 2, 2);
-    assertEqualBytes(bytes(0x02, 0x33, 0x44, 0x00), destination);
+    assertEqualBytes(OutputType.ARRAY, bytes(0x02, 0x33, 0x44, 0x00), destination);
     assertEquals(3, codedStream.getTotalBytesWritten());
   }
-  
+
+  public void testSerializeUtf8_MultipleSmallWrites() throws Exception {
+    final String source = "abcdefghijklmnopqrstuvwxyz";
+
+    // Generate the expected output if the source string is written 2 bytes at a time.
+    ByteArrayOutputStream expectedBytesStream = new ByteArrayOutputStream();
+    for (int pos = 0; pos < source.length(); pos += 2) {
+      String substr = source.substring(pos, pos + 2);
+      expectedBytesStream.write(2);
+      expectedBytesStream.write(substr.getBytes(Internal.UTF_8));
+    }
+    final byte[] expectedBytes = expectedBytesStream.toByteArray();
+
+    // For each output type, write the source string 2 bytes at a time and verify the output.
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(expectedBytes.length);
+      for (int pos = 0; pos < source.length(); pos += 2) {
+        String substr = source.substring(pos, pos + 2);
+        coder.stream().writeStringNoTag(substr);
+      }
+      coder.stream().flush();
+      assertEqualBytes(outputType, expectedBytes, coder.toByteArray());
+    }
+  }
+
   public void testSerializeInvalidUtf8() throws Exception {
-    String[] invalidStrings = new String[] {
-        newString(Character.MIN_HIGH_SURROGATE),
-        "foobar" + newString(Character.MIN_HIGH_SURROGATE),
-        newString(Character.MIN_LOW_SURROGATE),
+    String[] invalidStrings = new String[] {newString(Character.MIN_HIGH_SURROGATE),
+        "foobar" + newString(Character.MIN_HIGH_SURROGATE), newString(Character.MIN_LOW_SURROGATE),
         "foobar" + newString(Character.MIN_LOW_SURROGATE),
-        newString(Character.MIN_HIGH_SURROGATE, Character.MIN_HIGH_SURROGATE)
-    };
-    
+        newString(Character.MIN_HIGH_SURROGATE, Character.MIN_HIGH_SURROGATE)};
+
     CodedOutputStream outputWithStream = CodedOutputStream.newInstance(new ByteArrayOutputStream());
     CodedOutputStream outputWithArray = CodedOutputStream.newInstance(new byte[10000]);
+    CodedOutputStream outputWithByteBuffer =
+        CodedOutputStream.newInstance(ByteBuffer.allocate(10000));
     for (String s : invalidStrings) {
       // TODO(dweis): These should all fail; instead they are corrupting data.
       CodedOutputStream.computeStringSizeNoTag(s);
       outputWithStream.writeStringNoTag(s);
       outputWithArray.writeStringNoTag(s);
+      outputWithByteBuffer.writeStringNoTag(s);
     }
   }
-  
-  private static String newString(char... chars) {
-    return new String(chars);
+
+  // TODO(nathanmittler): This test can be deleted once we properly throw IOException while
+  // encoding invalid UTF-8 strings.
+  public void testSerializeInvalidUtf8FollowedByOutOfSpace() throws Exception {
+    final int notEnoughBytes = 4;
+    CodedOutputStream outputWithArray = CodedOutputStream.newInstance(new byte[notEnoughBytes]);
+    CodedOutputStream outputWithByteBuffer =
+        CodedOutputStream.newInstance(ByteBuffer.allocate(notEnoughBytes));
+
+    String invalidString = newString(Character.MIN_HIGH_SURROGATE, 'f', 'o', 'o', 'b', 'a', 'r');
+    try {
+      outputWithArray.writeStringNoTag(invalidString);
+      fail("Expected OutOfSpaceException");
+    } catch (OutOfSpaceException e) {
+      assertTrue(e.getCause() instanceof IndexOutOfBoundsException);
+    }
+    try {
+      outputWithByteBuffer.writeStringNoTag(invalidString);
+      fail("Expected OutOfSpaceException");
+    } catch (OutOfSpaceException e) {
+      assertTrue(e.getCause() instanceof IndexOutOfBoundsException);
+    }
   }
 
   /** Regression test for https://github.com/google/protobuf/issues/292 */
   public void testCorrectExceptionThrowWhenEncodingStringsWithoutEnoughSpace() throws Exception {
     String testCase = "Foooooooo";
-    assertEquals(CodedOutputStream.computeRawVarint32Size(testCase.length()),
-        CodedOutputStream.computeRawVarint32Size(testCase.length() * 3));
+    assertEquals(
+        CodedOutputStream.computeUInt32SizeNoTag(testCase.length()),
+        CodedOutputStream.computeUInt32SizeNoTag(testCase.length() * 3));
     assertEquals(11, CodedOutputStream.computeStringSize(1, testCase));
     // Tag is one byte, varint describing string length is 1 byte, string length is 9 bytes.
     // An array of size 1 will cause a failure when trying to write the varint.
-    for (int i = 0; i < 11; i++) {
-      CodedOutputStream output = CodedOutputStream.newInstance(new byte[i]);
-      try {
-        output.writeString(1, testCase);
-        fail("Should have thrown an out of space exception");
-      } catch (CodedOutputStream.OutOfSpaceException expected) {}
+    for (OutputType outputType :
+        new OutputType[] {OutputType.ARRAY, OutputType.NIO_HEAP, OutputType.NIO_DIRECT}) {
+      for (int i = 0; i < 11; i++) {
+        Coder coder = outputType.newCoder(i);
+        try {
+          coder.stream().writeString(1, testCase);
+          fail("Should have thrown an out of space exception");
+        } catch (CodedOutputStream.OutOfSpaceException expected) {
+        }
+      }
     }
   }
-  
+
   public void testDifferentStringLengths() throws Exception {
     // Test string serialization roundtrip using strings of the following lengths,
     // with ASCII and Unicode characters requiring different UTF-8 byte counts per
     // char, hence causing the length delimiter varint to sometimes require more
     // bytes for the Unicode strings than the ASCII string of the same length.
     int[] lengths = new int[] {
-            0,
-            1,
-            (1 << 4) - 1,  // 1 byte for ASCII and Unicode
-            (1 << 7) - 1,  // 1 byte for ASCII, 2 bytes for Unicode
-            (1 << 11) - 1, // 2 bytes for ASCII and Unicode
-            (1 << 14) - 1, // 2 bytes for ASCII, 3 bytes for Unicode
-            (1 << 17) - 1, // 3 bytes for ASCII and Unicode
+        0,
+        1,
+        (1 << 4) - 1, // 1 byte for ASCII and Unicode
+        (1 << 7) - 1, // 1 byte for ASCII, 2 bytes for Unicode
+        (1 << 11) - 1, // 2 bytes for ASCII and Unicode
+        (1 << 14) - 1, // 2 bytes for ASCII, 3 bytes for Unicode
+        (1 << 17) - 1,
+        // 3 bytes for ASCII and Unicode
     };
-    for (int i : lengths) {
-      testEncodingOfString('q', i);      // 1 byte per char
-      testEncodingOfString('\u07FF', i); // 2 bytes per char
-      testEncodingOfString('\u0981', i); // 3 bytes per char
+    for (OutputType outputType : OutputType.values()) {
+      for (int i : lengths) {
+        testEncodingOfString(outputType, 'q', i); // 1 byte per char
+        testEncodingOfString(outputType, '\u07FF', i); // 2 bytes per char
+        testEncodingOfString(outputType, '\u0981', i); // 3 bytes per char
+      }
     }
   }
 
-  private void testEncodingOfString(char c, int length) throws Exception {
+  public void testNioEncodersWithInitialOffsets() throws Exception {
+    String value = "abc";
+    for (Coder coder : new Coder[] {new NioHeapCoder(10, 2), new NioDirectCoder(10, 2)}) {
+      coder.stream().writeStringNoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(coder.getOutputType(), new byte[]{3, 'a', 'b', 'c'}, coder.toByteArray());
+    }
+  }
+
+  /**
+   * Parses the given bytes using writeRawLittleEndian32() and checks
+   * that the result matches the given value.
+   */
+  private static void assertWriteLittleEndian32(byte[] data, int value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(data.length);
+      coder.stream().writeFixed32NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(outputType, data, coder.toByteArray());
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      coder.stream().writeFixed32NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+    }
+  }
+
+  /**
+   * Parses the given bytes using writeRawLittleEndian64() and checks
+   * that the result matches the given value.
+   */
+  private static void assertWriteLittleEndian64(byte[] data, long value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      Coder coder = outputType.newCoder(data.length);
+      coder.stream().writeFixed64NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(outputType, data, coder.toByteArray());
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      Coder coder = OutputType.STREAM.newCoder(blockSize);
+      coder.stream().writeFixed64NoTag(value);
+      coder.stream().flush();
+      assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+    }
+  }
+
+  private static String newString(char... chars) {
+    return new String(chars);
+  }
+
+  private static void testEncodingOfString(OutputType outputType, char c, int length)
+      throws Exception {
     String fullString = fullString(c, length);
-    TestAllTypes testAllTypes = TestAllTypes.newBuilder()
-        .setOptionalString(fullString)
-        .build();
+    TestAllTypes testAllTypes = TestAllTypes.newBuilder().setOptionalString(fullString).build();
+    Coder coder = outputType.newCoder(testAllTypes.getSerializedSize());
+    testAllTypes.writeTo(coder.stream());
+    coder.stream().flush();
     assertEquals(
-        fullString, TestAllTypes.parseFrom(testAllTypes.toByteArray()).getOptionalString());
+        "OuputType: " + outputType,
+        fullString,
+        TestAllTypes.parseFrom(coder.toByteArray()).getOptionalString());
   }
 
-  private String fullString(char c, int length) {
+  private static String fullString(char c, int length) {
     char[] result = new char[length];
     Arrays.fill(result, c);
     return new String(result);
   }
+
+  /**
+   * Helper to construct a byte array from a bunch of bytes.  The inputs are
+   * actually ints so that I can use hex notation and not get stupid errors
+   * about precision.
+   */
+  private static byte[] bytes(int... bytesAsInts) {
+    byte[] bytes = new byte[bytesAsInts.length];
+    for (int i = 0; i < bytesAsInts.length; i++) {
+      bytes[i] = (byte) bytesAsInts[i];
+    }
+    return bytes;
+  }
+
+  /** Arrays.asList() does not work with arrays of primitives.  :( */
+  private static List<Byte> toList(byte[] bytes) {
+    List<Byte> result = new ArrayList<Byte>();
+    for (byte b : bytes) {
+      result.add(b);
+    }
+    return result;
+  }
+
+  private static void assertEqualBytes(OutputType outputType, byte[] a, byte[] b) {
+    assertEquals(outputType.name(), toList(a), toList(b));
+  }
+
+  /**
+   * Writes the given value using writeRawVarint32() and writeRawVarint64() and
+   * checks that the result matches the given bytes.
+   */
+  private static void assertWriteVarint(byte[] data, long value) throws Exception {
+    for (OutputType outputType : OutputType.values()) {
+      // Only test 32-bit write if the value fits into an int.
+      if (value == (int) value) {
+        Coder coder = outputType.newCoder(10);
+        coder.stream().writeUInt32NoTag((int) value);
+        coder.stream().flush();
+        assertEqualBytes(outputType, data, coder.toByteArray());
+
+        // Also try computing size.
+        assertEquals(data.length, CodedOutputStream.computeUInt32SizeNoTag((int) value));
+      }
+
+      {
+        Coder coder = outputType.newCoder(10);
+        coder.stream().writeUInt64NoTag(value);
+        coder.stream().flush();
+        assertEqualBytes(outputType, data, coder.toByteArray());
+
+        // Also try computing size.
+        assertEquals(data.length, CodedOutputStream.computeUInt64SizeNoTag(value));
+      }
+    }
+
+    // Try different block sizes.
+    for (int blockSize = 1; blockSize <= 16; blockSize *= 2) {
+      // Only test 32-bit write if the value fits into an int.
+      if (value == (int) value) {
+        Coder coder = OutputType.STREAM.newCoder(blockSize);
+        coder.stream().writeUInt64NoTag((int) value);
+        coder.stream().flush();
+        assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+
+        ByteArrayOutputStream rawOutput = new ByteArrayOutputStream();
+        CodedOutputStream output = CodedOutputStream.newInstance(rawOutput, blockSize);
+        output.writeUInt32NoTag((int) value);
+        output.flush();
+        assertEqualBytes(OutputType.STREAM, data, rawOutput.toByteArray());
+      }
+
+      {
+        Coder coder = OutputType.STREAM.newCoder(blockSize);
+        coder.stream().writeUInt64NoTag(value);
+        coder.stream().flush();
+        assertEqualBytes(OutputType.STREAM, data, coder.toByteArray());
+      }
+    }
+  }
+
+  private static void assertVarintRoundTrip(OutputType outputType, long value) throws Exception {
+    {
+      Coder coder = outputType.newCoder(10);
+      coder.stream().writeUInt64NoTag(value);
+      coder.stream().flush();
+      byte[] bytes = coder.toByteArray();
+      assertEquals(
+          outputType.name(), bytes.length, CodedOutputStream.computeUInt64SizeNoTag(value));
+      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
+      assertEquals(outputType.name(), value, input.readRawVarint64());
+    }
+
+    if (value == (int) value) {
+      Coder coder = outputType.newCoder(10);
+      coder.stream().writeUInt32NoTag((int) value);
+      coder.stream().flush();
+      byte[] bytes = coder.toByteArray();
+      assertEquals(
+          outputType.name(), bytes.length, CodedOutputStream.computeUInt32SizeNoTag((int) value));
+      CodedInputStream input = CodedInputStream.newInstance(new ByteArrayInputStream(bytes));
+      assertEquals(outputType.name(), value, input.readRawVarint32());
+    }
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java b/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
index d3deaa07..85b418c4 100644
--- a/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/DoubleArrayListTest.java
@@ -73,20 +73,6 @@ public class DoubleArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    DoubleArrayList copy = new DoubleArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new DoubleArrayList(DoubleArrayList.emptyList());
-    assertEquals(DoubleArrayList.emptyList(), copy);
-    
-    copy = new DoubleArrayList(asList(1D, 2D, 3D));
-    assertEquals(asList(1D, 2D, 3D), copy);
-
-    copy = new DoubleArrayList(Collections.<Double>emptyList());
-    assertEquals(DoubleArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1D, 2D, 3D, 4D));
     Iterator<Double> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java b/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
index a5e65424..88a75743 100644
--- a/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/FloatArrayListTest.java
@@ -73,20 +73,6 @@ public class FloatArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    FloatArrayList copy = new FloatArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new FloatArrayList(FloatArrayList.emptyList());
-    assertEquals(FloatArrayList.emptyList(), copy);
-    
-    copy = new FloatArrayList(asList(1F, 2F, 3F));
-    assertEquals(asList(1F, 2F, 3F), copy);
-
-    copy = new FloatArrayList(Collections.<Float>emptyList());
-    assertEquals(FloatArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1F, 2F, 3F, 4F));
     Iterator<Float> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java b/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
index a92ba374..b7eaebf5 100644
--- a/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
+++ b/java/core/src/test/java/com/google/protobuf/ForceFieldBuildersPreRun.java
@@ -41,7 +41,7 @@ package com.google.protobuf;
  */
 public class ForceFieldBuildersPreRun implements Runnable {
 
-  //@Override (Java 1.6 override semantics, but we must support 1.5)
+  @Override
   public void run() {
     GeneratedMessage.enableAlwaysUseFieldBuildersForTesting();
   }
diff --git a/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java b/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
index 8cd1f38d..a9b8b638 100644
--- a/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
+++ b/java/core/src/test/java/com/google/protobuf/GeneratedMessageTest.java
@@ -723,7 +723,7 @@ public class GeneratedMessageTest extends TestCase {
 
   public void testLiteExtensionMessageOrBuilder() throws Exception {
     TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    TestUtil.setAllExtensions(builder);
+    TestUtilLite.setAllExtensions(builder);
     TestUtil.assertAllExtensionsSet(builder);
 
     TestAllExtensionsLite message = builder.build();
@@ -732,8 +732,8 @@ public class GeneratedMessageTest extends TestCase {
 
   public void testLiteExtensionRepeatedSetters() throws Exception {
     TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    TestUtil.setAllExtensions(builder);
-    TestUtil.modifyRepeatedExtensions(builder);
+    TestUtilLite.setAllExtensions(builder);
+    TestUtilLite.modifyRepeatedExtensions(builder);
     TestUtil.assertRepeatedExtensionsModified(builder);
 
     TestAllExtensionsLite message = builder.build();
@@ -760,7 +760,7 @@ public class GeneratedMessageTest extends TestCase {
   }
 
   public void testLiteExtensionCopy() throws Exception {
-    TestAllExtensionsLite original = TestUtil.getAllLiteExtensionsSet();
+    TestAllExtensionsLite original = TestUtilLite.getAllLiteExtensionsSet();
     TestAllExtensionsLite copy =
         TestAllExtensionsLite.newBuilder(original).build();
     TestUtil.assertAllExtensionsSet(copy);
diff --git a/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java b/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
index 3733eb30..efb8f3e2 100644
--- a/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/IntArrayListTest.java
@@ -72,20 +72,6 @@ public class IntArrayListTest extends TestCase {
     list.makeImmutable();
     assertImmutable(list);
   }
-  
-  public void testCopyConstructor() {
-    IntArrayList copy = new IntArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new IntArrayList(IntArrayList.emptyList());
-    assertEquals(IntArrayList.emptyList(), copy);
-    
-    copy = new IntArrayList(asList(1, 2, 3));
-    assertEquals(asList(1, 2, 3), copy);
-
-    copy = new IntArrayList(Collections.<Integer>emptyList());
-    assertEquals(IntArrayList.emptyList(), copy);
-  }
 
   public void testModificationWithIteration() {
     list.addAll(asList(1, 2, 3, 4));
diff --git a/java/core/src/test/java/com/google/protobuf/LiteTest.java b/java/core/src/test/java/com/google/protobuf/LiteTest.java
index 9e503cc3..88c3e0b2 100644
--- a/java/core/src/test/java/com/google/protobuf/LiteTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LiteTest.java
@@ -33,17 +33,25 @@ package com.google.protobuf;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 
+import com.google.protobuf.UnittestImportLite.ImportEnumLite;
+import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
 import com.google.protobuf.UnittestLite;
 import com.google.protobuf.UnittestLite.ForeignEnumLite;
 import com.google.protobuf.UnittestLite.ForeignMessageLite;
 import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
 import com.google.protobuf.UnittestLite.TestAllTypesLite;
+import com.google.protobuf.UnittestLite.TestAllTypesLite.NestedEnum;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.NestedMessage;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.OneofFieldCase;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.OptionalGroup;
 import com.google.protobuf.UnittestLite.TestAllTypesLite.RepeatedGroup;
 import com.google.protobuf.UnittestLite.TestAllTypesLiteOrBuilder;
 import com.google.protobuf.UnittestLite.TestNestedExtensionLite;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Bar;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.BarPrime;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.Foo;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.TestOneofEquals;
+import protobuf_unittest.lite_equals_and_hash.LiteEqualsAndHash.TestRecursiveOneof;
 
 import junit.framework.TestCase;
 
@@ -59,6 +67,7 @@ import java.io.ObjectOutputStream;
  * @author kenton@google.com Kenton Varda
  */
 public class LiteTest extends TestCase {
+  @Override
   public void setUp() throws Exception {
     // Test that nested extensions are initialized correctly even if the outer
     // class has not been accessed directly.  This was once a bug with lite
@@ -302,11 +311,9 @@ public class LiteTest extends TestCase {
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         message.getOptionalForeignMessage());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on foreignMessage.
-    assertEquals(3, builder.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), builder.getOptionalForeignMessage());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getOptionalForeignMessage());
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         message.getOptionalForeignMessage());
@@ -314,7 +321,7 @@ public class LiteTest extends TestCase {
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         builder.getOptionalForeignMessage());
-    assertEquals(3, messageAfterBuild.getOptionalForeignMessage().getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getOptionalForeignMessage());
 
     message = builder.build();
     OptionalGroup optionalGroup = OptionalGroup.newBuilder()
@@ -339,17 +346,15 @@ public class LiteTest extends TestCase {
     builder.setOptionalGroup(optionalGroupBuilder);
     assertEquals(
         OptionalGroup.getDefaultInstance(), message.getOptionalGroup());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on optionalGroup.
-    assertEquals(3, builder.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), builder.getOptionalGroup());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), messageAfterBuild.getOptionalGroup());
     assertEquals(
         OptionalGroup.getDefaultInstance(), message.getOptionalGroup());
     builder.clearOptionalGroup();
     assertEquals(
         OptionalGroup.getDefaultInstance(), builder.getOptionalGroup());
-    assertEquals(3, messageAfterBuild.getOptionalGroup().getA());
+    assertEquals(optionalGroupBuilder.build(), messageAfterBuild.getOptionalGroup());
 
     message = builder.build();
     builder.setOptionalInt32(1);
@@ -400,17 +405,16 @@ public class LiteTest extends TestCase {
     assertEquals(
         NestedMessage.getDefaultInstance(),
         message.getOptionalLazyMessage());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, builder.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), builder.getOptionalLazyMessage());
     messageAfterBuild = builder.build();
-    assertEquals(3, messageAfterBuild.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getOptionalLazyMessage());
     assertEquals(
         NestedMessage.getDefaultInstance(),
         message.getOptionalLazyMessage());
     builder.clearOptionalLazyMessage();
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getOptionalLazyMessage());
-    assertEquals(3, messageAfterBuild.getOptionalLazyMessage().getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getOptionalLazyMessage());
 
     message = builder.build();
     builder.setOptionalSfixed32(1);
@@ -1100,8 +1104,7 @@ public class LiteTest extends TestCase {
     assertEquals(0, message.getRepeatedForeignMessageCount());
     builder.setRepeatedForeignMessage(
         0, ForeignMessageLite.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, messageAfterBuild.getRepeatedForeignMessage(0).getC());
+    assertEquals(foreignMessageBuilder.build(), messageAfterBuild.getRepeatedForeignMessage(0));
     assertEquals(
         ForeignMessageLite.getDefaultInstance(),
         builder.getRepeatedForeignMessage(0));
@@ -1114,8 +1117,7 @@ public class LiteTest extends TestCase {
     builder.setRepeatedForeignMessage(0, foreignMessageBuilder);
     assertEquals(
         foreignMessage, messageAfterBuild.getRepeatedForeignMessage(0));
-    // LITE_RUNTIME doesn't implement equals so we compare on a property.
-    assertEquals(3, builder.getRepeatedForeignMessage(0).getC());
+    assertEquals(foreignMessageBuilder.build(), builder.getRepeatedForeignMessage(0));
     builder.clearRepeatedForeignMessage();
 
     message = builder.build();
@@ -1148,9 +1150,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedGroupCount());
     builder.setRepeatedGroup(0, RepeatedGroup.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedGroup(0).getA());
+    assertEquals(repeatedGroupBuilder.build(), messageAfterBuild.getRepeatedGroup(0));
     assertEquals(
         RepeatedGroup.getDefaultInstance(), builder.getRepeatedGroup(0));
     builder.clearRepeatedGroup();
@@ -1160,9 +1160,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedGroupCount());
     builder.setRepeatedGroup(0, RepeatedGroup.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedGroup(0).getA());
+    assertEquals(repeatedGroupBuilder.build(), messageAfterBuild.getRepeatedGroup(0));
     assertEquals(
         RepeatedGroup.getDefaultInstance(), builder.getRepeatedGroup(0));
     builder.clearRepeatedGroup();
@@ -1210,9 +1208,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedLazyMessageCount());
     builder.setRepeatedLazyMessage(0, NestedMessage.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedLazyMessage(0).getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getRepeatedLazyMessage(0));
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getRepeatedLazyMessage(0));
     builder.clearRepeatedLazyMessage();
@@ -1222,9 +1218,7 @@ public class LiteTest extends TestCase {
     messageAfterBuild = builder.build();
     assertEquals(0, message.getRepeatedLazyMessageCount());
     builder.setRepeatedLazyMessage(0, NestedMessage.getDefaultInstance());
-    // LITE_RUNTIME doesn't implement equals so we compare on a property and
-    // ensure the property isn't set on repeatedGroup.
-    assertEquals(3, messageAfterBuild.getRepeatedLazyMessage(0).getBb());
+    assertEquals(nestedMessageBuilder.build(), messageAfterBuild.getRepeatedLazyMessage(0));
     assertEquals(
         NestedMessage.getDefaultInstance(), builder.getRepeatedLazyMessage(0));
     builder.clearRepeatedLazyMessage();
@@ -1456,7 +1450,7 @@ public class LiteTest extends TestCase {
         .setOptionalFloat(2.72f)
         .setOptionalDouble(3.14)
         .build();
-    assertToStringEquals("optional_float: 2.72\noptional_double: 3.14", proto);
+    assertToStringEquals("optional_double: 3.14\noptional_float: 2.72", proto);
   }
 
   public void testToStringStringFields() throws Exception {
@@ -1511,7 +1505,7 @@ public class LiteTest extends TestCase {
             .setC(3))
         .build();
     assertToStringEquals(
-        "optional_foreign_message {\n  c: 3\n}\noptional_foreign_enum: FOREIGN_LITE_BAR",
+        "optional_foreign_enum: FOREIGN_LITE_BAR\noptional_foreign_message {\n  c: 3\n}",
         proto);
   }
 
@@ -1546,6 +1540,27 @@ public class LiteTest extends TestCase {
         "1: 123\n18: \"\\b\\a\"\n21: 3\n44: \"spam\"\n44: \"eggs\"",
         messageWithUnknownFields);
   }
+  
+  public void testToStringLazyMessage() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.newBuilder().setBb(1).build())
+        .build();
+    assertToStringEquals("optional_lazy_message {\n  bb: 1\n}", message);
+  }
+  
+  public void testToStringGroup() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOptionalGroup(OptionalGroup.newBuilder().setA(1).build())
+        .build();
+    assertToStringEquals("optional_group {\n  a: 1\n}", message);
+  }
+  
+  public void testToStringOneof() throws Exception {
+    TestAllTypesLite message = TestAllTypesLite.newBuilder()
+        .setOneofString("hello")
+        .build();
+    assertToStringEquals("oneof_string: \"hello\"", message);
+  }
 
   // Asserts that the toString() representation of the message matches the expected. This verifies
   // the first line starts with a comment; but, does not factor in said comment as part of the
@@ -1598,4 +1613,617 @@ public class LiteTest extends TestCase {
     assertEquals(11, message.getOneofLazyNestedMessage().getBb());
     assertEquals(22L, message.getOneofLazyNestedMessage().getCc());
   }
+
+  public void testMergeFromStream_repeatedField() throws Exception {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder()
+        .addRepeatedString("hello");
+    builder.mergeFrom(CodedInputStream.newInstance(builder.build().toByteArray()));
+
+    assertEquals(2, builder.getRepeatedStringCount());
+  }
+
+  public void testMergeFromStream_invalidBytes() throws Exception {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder()
+        .setDefaultBool(true);
+    try {
+      builder.mergeFrom(CodedInputStream.newInstance("Invalid bytes".getBytes(Internal.UTF_8)));
+      fail();
+    } catch (InvalidProtocolBufferException expected) {}
+  }
+  
+  public void testMergeFrom_sanity() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    byte[] bytes = one.toByteArray();
+    TestAllTypesLite two = TestAllTypesLite.parseFrom(bytes);
+    
+    one = one.toBuilder().mergeFrom(one).build();
+    two = two.toBuilder().mergeFrom(bytes).build();
+    assertEquals(one, two);
+    assertEquals(two, one);
+    assertEquals(one.hashCode(), two.hashCode());
+  }
+  
+  public void testEquals_notEqual() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    byte[] bytes = one.toByteArray();
+    TestAllTypesLite two = one.toBuilder().mergeFrom(one).mergeFrom(bytes).build();
+    
+    assertFalse(one.equals(two));
+    assertFalse(two.equals(one));
+    
+    assertFalse(one.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(one));
+    
+    TestAllTypesLite oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setDefaultUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalBool(true)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalCord("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalCordBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalDouble(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalFloat(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalImportEnum(ImportEnumLite.IMPORT_LITE_BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalInt32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalInt64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalNestedEnum(NestedEnum.BAR)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSfixed32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSfixed64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalSint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringPiece("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalStringPieceBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalUint64(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofLazyNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofString("")
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofStringBytes(ByteString.EMPTY)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOneofUint32(0)
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalForeignMessage(ForeignMessageLite.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalGroup(OptionalGroup.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalPublicImportMessage(PublicImportMessageLite.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .setOptionalLazyMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+    oneFieldSet = TestAllTypesLite.newBuilder()
+        .addRepeatedLazyMessage(NestedMessage.getDefaultInstance())
+        .build();
+    assertFalse(oneFieldSet.equals(TestAllTypesLite.getDefaultInstance()));
+    assertFalse(TestAllTypesLite.getDefaultInstance().equals(oneFieldSet));
+  }
+
+  public void testEquals() throws Exception {
+    // Check that two identical objs are equal.
+    Foo foo1a = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo1"))
+        .build();
+    Foo foo1b = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo1"))
+        .build();
+    Foo foo2 = Foo.newBuilder()
+        .setValue(1)
+        .addBar(Bar.newBuilder().setName("foo2"))
+        .build();
+
+    // Check that equals is doing value rather than object equality.
+    assertEquals(foo1a, foo1b);
+    assertEquals(foo1a.hashCode(), foo1b.hashCode());
+
+    // Check that a diffeent object is not equal.
+    assertFalse(foo1a.equals(foo2));
+
+    // Check that two objects which have different types but the same field values are not
+    // considered to be equal.
+    Bar bar = Bar.newBuilder().setName("bar").build();
+    BarPrime barPrime = BarPrime.newBuilder().setName("bar").build();
+    assertFalse(bar.equals(barPrime));
+  }
+
+  public void testOneofEquals() throws Exception {
+    TestOneofEquals.Builder builder = TestOneofEquals.newBuilder();
+    TestOneofEquals message1 = builder.build();
+    // Set message2's name field to default value. The two messages should be different when we
+    // check with the oneof case.
+    builder.setName("");
+    TestOneofEquals message2 = builder.build();
+    assertFalse(message1.equals(message2));
+  }
+  
+  public void testEquals_sanity() throws Exception {
+    TestAllTypesLite one = TestUtilLite.getAllLiteSetBuilder().build();
+    TestAllTypesLite two = TestAllTypesLite.parseFrom(one.toByteArray());
+    assertEquals(one, two);
+    assertEquals(one.hashCode(), two.hashCode());
+    
+    assertEquals(
+        one.toBuilder().mergeFrom(two).build(),
+        two.toBuilder().mergeFrom(two.toByteArray()).build());
+  }
+
+  public void testEqualsAndHashCodeWithUnknownFields() throws InvalidProtocolBufferException {
+    Foo fooWithOnlyValue = Foo.newBuilder()
+        .setValue(1)
+        .build();
+
+    Foo fooWithValueAndExtension = fooWithOnlyValue.toBuilder()
+        .setValue(1)
+        .setExtension(Bar.fooExt, Bar.newBuilder()
+            .setName("name")
+            .build())
+        .build();
+
+    Foo fooWithValueAndUnknownFields = Foo.parseFrom(fooWithValueAndExtension.toByteArray());
+
+    assertEqualsAndHashCodeAreFalse(fooWithOnlyValue, fooWithValueAndUnknownFields);
+    assertEqualsAndHashCodeAreFalse(fooWithValueAndExtension, fooWithValueAndUnknownFields);
+  }
+  
+  // Test to ensure we avoid a class cast exception with oneofs.
+  public void testEquals_oneOfMessages() {
+    TestAllTypesLite mine = TestAllTypesLite.newBuilder()
+        .setOneofString("Hello")
+        .build();
+    
+    TestAllTypesLite other = TestAllTypesLite.newBuilder()
+        .setOneofNestedMessage(NestedMessage.getDefaultInstance())
+        .build();
+    
+    assertFalse(mine.equals(other));
+    assertFalse(other.equals(mine));
+  }
+
+  private void assertEqualsAndHashCodeAreFalse(Object o1, Object o2) {
+    assertFalse(o1.equals(o2));
+    assertFalse(o1.hashCode() == o2.hashCode());
+  }
+
+  public void testRecursiveHashcode() {
+    // This tests that we don't infinite loop.
+    TestRecursiveOneof.getDefaultInstance().hashCode();
+  }
 }
diff --git a/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java b/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
index 1bd094f7..0a8f9ed2 100644
--- a/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/LongArrayListTest.java
@@ -73,20 +73,6 @@ public class LongArrayListTest extends TestCase {
     assertImmutable(list);
   }
   
-  public void testCopyConstructor() {
-    LongArrayList copy = new LongArrayList(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new LongArrayList(LongArrayList.emptyList());
-    assertEquals(LongArrayList.emptyList(), copy);
-    
-    copy = new LongArrayList(asList(1L, 2L, 3L));
-    assertEquals(asList(1L, 2L, 3L), copy);
-
-    copy = new LongArrayList(Collections.<Long>emptyList());
-    assertEquals(LongArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1L, 2L, 3L, 4L));
     Iterator<Long> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ParserTest.java b/java/core/src/test/java/com/google/protobuf/ParserTest.java
index 9d4b6b94..30842d2c 100644
--- a/java/core/src/test/java/com/google/protobuf/ParserTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ParserTest.java
@@ -179,16 +179,16 @@ public class ParserTest extends TestCase {
   public void testParseExtensions() throws Exception {
     assertRoundTripEquals(TestUtil.getAllExtensionsSet(),
                           TestUtil.getExtensionRegistry());
-    assertRoundTripEquals(TestUtil.getAllLiteExtensionsSet(),
-                          TestUtil.getExtensionRegistryLite());
+    assertRoundTripEquals(
+        TestUtilLite.getAllLiteExtensionsSet(), TestUtilLite.getExtensionRegistryLite());
   }
 
   public void testParsePacked() throws Exception {
     assertRoundTripEquals(TestUtil.getPackedSet());
     assertRoundTripEquals(TestUtil.getPackedExtensionsSet(),
                           TestUtil.getExtensionRegistry());
-    assertRoundTripEquals(TestUtil.getLitePackedExtensionsSet(),
-                          TestUtil.getExtensionRegistryLite());
+    assertRoundTripEquals(
+        TestUtilLite.getLitePackedExtensionsSet(), TestUtilLite.getExtensionRegistryLite());
   }
 
   public void testParseDelimitedTo() throws Exception {
@@ -198,8 +198,7 @@ public class ParserTest extends TestCase {
     normalMessage.writeDelimitedTo(output);
 
     // Write MessageLite with packed extension fields.
-    TestPackedExtensionsLite packedMessage =
-        TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite packedMessage = TestUtilLite.getLitePackedExtensionsSet();
     packedMessage.writeDelimitedTo(output);
 
     InputStream input = new ByteArrayInputStream(output.toByteArray());
@@ -208,8 +207,9 @@ public class ParserTest extends TestCase {
         normalMessage.getParserForType().parseDelimitedFrom(input));
     assertMessageEquals(
         packedMessage,
-        packedMessage.getParserForType().parseDelimitedFrom(
-            input, TestUtil.getExtensionRegistryLite()));
+        packedMessage
+            .getParserForType()
+            .parseDelimitedFrom(input, TestUtilLite.getExtensionRegistryLite()));
   }
 
   public void testParseUnknownFields() throws Exception {
diff --git a/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java b/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
index 245c3dee..3f45e226 100644
--- a/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ProtobufArrayListTest.java
@@ -63,20 +63,6 @@ public class ProtobufArrayListTest extends TestCase {
     assertImmutable(ProtobufArrayList.<Integer>emptyList());
   }
   
-  public void testCopyConstructor() {
-    ProtobufArrayList<Integer> copy = new ProtobufArrayList<Integer>(TERTIARY_LIST);
-    assertEquals(TERTIARY_LIST, copy);
-
-    copy = new ProtobufArrayList<Integer>(IntArrayList.emptyList());
-    assertEquals(ProtobufArrayList.emptyList(), copy);
-    
-    copy = new ProtobufArrayList<Integer>(asList(1, 2, 3));
-    assertEquals(asList(1, 2, 3), copy);
-
-    copy = new ProtobufArrayList<Integer>(Collections.<Integer>emptyList());
-    assertEquals(ProtobufArrayList.emptyList(), copy);
-  }
-  
   public void testModificationWithIteration() {
     list.addAll(asList(1, 2, 3, 4));
     Iterator<Integer> iterator = list.iterator();
diff --git a/java/core/src/test/java/com/google/protobuf/ServiceTest.java b/java/core/src/test/java/com/google/protobuf/ServiceTest.java
index 7f3439d0..b902737d 100644
--- a/java/core/src/test/java/com/google/protobuf/ServiceTest.java
+++ b/java/core/src/test/java/com/google/protobuf/ServiceTest.java
@@ -175,12 +175,14 @@ public class ServiceTest extends TestCase {
     MethodDescriptor fooMethod =
         ServiceWithNoOuter.getDescriptor().findMethodByName("Foo");
     MessageWithNoOuter request = MessageWithNoOuter.getDefaultInstance();
-    RpcCallback<Message> callback = new RpcCallback<Message>() {
-      public void run(Message parameter) {
-        // No reason this should be run.
-        fail();
-      }
-    };
+    RpcCallback<Message> callback =
+        new RpcCallback<Message>() {
+          @Override
+          public void run(Message parameter) {
+            // No reason this should be run.
+            fail();
+          }
+        };
     RpcCallback<TestAllTypes> specializedCallback =
         RpcUtil.specializeCallback(callback);
 
@@ -290,7 +292,9 @@ public class ServiceTest extends TestCase {
     public boolean isCalled() { return called; }
 
     public void reset() { called = false; }
-    public void run(Type message) { called = true; }
+    @Override
+    public void run(Type message) {
+      called = true; }
   }
 
   /** Implementation of the wrapsCallback() argument matcher. */
@@ -301,6 +305,7 @@ public class ServiceTest extends TestCase {
       this.callback = callback;
     }
 
+    @Override
     @SuppressWarnings("unchecked")
     public boolean matches(Object actual) {
       if (!(actual instanceof RpcCallback)) {
@@ -313,6 +318,7 @@ public class ServiceTest extends TestCase {
       return callback.isCalled();
     }
 
+    @Override
     public void appendTo(StringBuffer buffer) {
       buffer.append("wrapsCallback(mockCallback)");
     }
diff --git a/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java b/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
index 366086d3..e96ecd65 100644
--- a/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
+++ b/java/core/src/test/java/com/google/protobuf/SmallSortedMapTest.java
@@ -56,14 +56,17 @@ public class SmallSortedMapTest extends TestCase {
       this.value = value;
     }
 
+    @Override
     public K getKey() {
       return key;
     }
 
+    @Override
     public V getValue() {
       return value;
     }
 
+    @Override
     public V setValue(V value) {
       V oldValue = this.value;
       this.value = value;
diff --git a/java/core/src/test/java/com/google/protobuf/TestUtil.java b/java/core/src/test/java/com/google/protobuf/TestUtil.java
index 53d65428..08b2a76d 100644
--- a/java/core/src/test/java/com/google/protobuf/TestUtil.java
+++ b/java/core/src/test/java/com/google/protobuf/TestUtil.java
@@ -30,8 +30,6 @@
 
 package com.google.protobuf;
 
-import static com.google.protobuf.UnittestLite.OptionalGroup_extension_lite;
-import static com.google.protobuf.UnittestLite.RepeatedGroup_extension_lite;
 import static com.google.protobuf.UnittestLite.defaultBoolExtensionLite;
 import static com.google.protobuf.UnittestLite.defaultBytesExtensionLite;
 import static com.google.protobuf.UnittestLite.defaultCordExtensionLite;
@@ -216,12 +214,7 @@ import static protobuf_unittest.UnittestProto.repeatedUint32Extension;
 import static protobuf_unittest.UnittestProto.repeatedUint64Extension;
 
 import com.google.protobuf.UnittestImportLite.ImportEnumLite;
-import com.google.protobuf.UnittestImportLite.ImportMessageLite;
-import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
-import com.google.protobuf.UnittestLite;
 import com.google.protobuf.UnittestLite.ForeignEnumLite;
-import com.google.protobuf.UnittestLite.ForeignMessageLite;
-import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
 import com.google.protobuf.UnittestLite.TestAllExtensionsLiteOrBuilder;
 import com.google.protobuf.UnittestLite.TestAllTypesLite;
 import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
@@ -287,16 +280,6 @@ public final class TestUtil {
   }
 
   /**
-   * Get a {@code TestAllTypesLite.Builder} with all fields set as they would be by
-   * {@link #setAllFields(TestAllTypesLite.Builder)}.
-   */
-  public static TestAllTypesLite.Builder getAllLiteSetBuilder() {
-    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder();
-    setAllFields(builder);
-    return builder;
-  }
-
-  /**
    * Get a {@code TestAllExtensions} with all fields set as they would be by
    * {@link #setAllExtensions(TestAllExtensions.Builder)}.
    */
@@ -306,12 +289,6 @@ public final class TestUtil {
     return builder.build();
   }
 
-  public static TestAllExtensionsLite getAllLiteExtensionsSet() {
-    TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
-    setAllExtensions(builder);
-    return builder.build();
-  }
-
   public static TestPackedTypes getPackedSet() {
     TestPackedTypes.Builder builder = TestPackedTypes.newBuilder();
     setPackedFields(builder);
@@ -330,157 +307,6 @@ public final class TestUtil {
     return builder.build();
   }
 
-  public static TestPackedExtensionsLite getLitePackedExtensionsSet() {
-    TestPackedExtensionsLite.Builder builder =
-        TestPackedExtensionsLite.newBuilder();
-    setPackedExtensions(builder);
-    return builder.build();
-  }
-  
-  /**
-   * Set every field of {@code builder} to the values expected by
-   * {@code assertAllFieldsSet()}.
-   */
-  public static void setAllFields(TestAllTypesLite.Builder builder) {
-    builder.setOptionalInt32   (101);
-    builder.setOptionalInt64   (102);
-    builder.setOptionalUint32  (103);
-    builder.setOptionalUint64  (104);
-    builder.setOptionalSint32  (105);
-    builder.setOptionalSint64  (106);
-    builder.setOptionalFixed32 (107);
-    builder.setOptionalFixed64 (108);
-    builder.setOptionalSfixed32(109);
-    builder.setOptionalSfixed64(110);
-    builder.setOptionalFloat   (111);
-    builder.setOptionalDouble  (112);
-    builder.setOptionalBool    (true);
-    builder.setOptionalString  ("115");
-    builder.setOptionalBytes   (toBytes("116"));
-
-    builder.setOptionalGroup(
-        TestAllTypesLite.OptionalGroup.newBuilder().setA(117).build());
-    builder.setOptionalNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
-    builder.setOptionalForeignMessage(
-        ForeignMessageLite.newBuilder().setC(119).build());
-    builder.setOptionalImportMessage(
-        ImportMessageLite.newBuilder().setD(120).build());
-    builder.setOptionalPublicImportMessage(
-        PublicImportMessageLite.newBuilder().setE(126).build());
-    builder.setOptionalLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
-
-    builder.setOptionalNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
-    builder.setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
-    builder.setOptionalImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
-
-    builder.setOptionalStringPiece("124");
-    builder.setOptionalCord("125");
-
-    // -----------------------------------------------------------------
-
-    builder.addRepeatedInt32   (201);
-    builder.addRepeatedInt64   (202);
-    builder.addRepeatedUint32  (203);
-    builder.addRepeatedUint64  (204);
-    builder.addRepeatedSint32  (205);
-    builder.addRepeatedSint64  (206);
-    builder.addRepeatedFixed32 (207);
-    builder.addRepeatedFixed64 (208);
-    builder.addRepeatedSfixed32(209);
-    builder.addRepeatedSfixed64(210);
-    builder.addRepeatedFloat   (211);
-    builder.addRepeatedDouble  (212);
-    builder.addRepeatedBool    (true);
-    builder.addRepeatedString  ("215");
-    builder.addRepeatedBytes   (toBytes("216"));
-
-    builder.addRepeatedGroup(
-        TestAllTypesLite.RepeatedGroup.newBuilder().setA(217).build());
-    builder.addRepeatedNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
-    builder.addRepeatedForeignMessage(
-        ForeignMessageLite.newBuilder().setC(219).build());
-    builder.addRepeatedImportMessage(
-        ImportMessageLite.newBuilder().setD(220).build());
-    builder.addRepeatedLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
-
-    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAR);
-    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR);
-    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAR);
-
-    builder.addRepeatedStringPiece("224");
-    builder.addRepeatedCord("225");
-
-    // Add a second one of each field.
-    builder.addRepeatedInt32   (301);
-    builder.addRepeatedInt64   (302);
-    builder.addRepeatedUint32  (303);
-    builder.addRepeatedUint64  (304);
-    builder.addRepeatedSint32  (305);
-    builder.addRepeatedSint64  (306);
-    builder.addRepeatedFixed32 (307);
-    builder.addRepeatedFixed64 (308);
-    builder.addRepeatedSfixed32(309);
-    builder.addRepeatedSfixed64(310);
-    builder.addRepeatedFloat   (311);
-    builder.addRepeatedDouble  (312);
-    builder.addRepeatedBool    (false);
-    builder.addRepeatedString  ("315");
-    builder.addRepeatedBytes   (toBytes("316"));
-
-    builder.addRepeatedGroup(
-        TestAllTypesLite.RepeatedGroup.newBuilder().setA(317).build());
-    builder.addRepeatedNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
-    builder.addRepeatedForeignMessage(
-        ForeignMessageLite.newBuilder().setC(319).build());
-    builder.addRepeatedImportMessage(
-        ImportMessageLite.newBuilder().setD(320).build());
-    builder.addRepeatedLazyMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
-
-    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
-    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
-    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
-
-    builder.addRepeatedStringPiece("324");
-    builder.addRepeatedCord("325");
-
-    // -----------------------------------------------------------------
-
-    builder.setDefaultInt32   (401);
-    builder.setDefaultInt64   (402);
-    builder.setDefaultUint32  (403);
-    builder.setDefaultUint64  (404);
-    builder.setDefaultSint32  (405);
-    builder.setDefaultSint64  (406);
-    builder.setDefaultFixed32 (407);
-    builder.setDefaultFixed64 (408);
-    builder.setDefaultSfixed32(409);
-    builder.setDefaultSfixed64(410);
-    builder.setDefaultFloat   (411);
-    builder.setDefaultDouble  (412);
-    builder.setDefaultBool    (false);
-    builder.setDefaultString  ("415");
-    builder.setDefaultBytes   (toBytes("416"));
-
-    builder.setDefaultNestedEnum (TestAllTypesLite.NestedEnum.FOO);
-    builder.setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_FOO);
-    builder.setDefaultImportEnum (ImportEnumLite.IMPORT_LITE_FOO);
-
-    builder.setDefaultStringPiece("424");
-    builder.setDefaultCord("425");
-
-    builder.setOneofUint32(601);
-    builder.setOneofNestedMessage(
-        TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
-    builder.setOneofString("603");
-    builder.setOneofBytes(toBytes("604"));
-  }
-
   /**
    * Set every field of {@code message} to the values expected by
    * {@code assertAllFieldsSet()}.
@@ -1370,23 +1196,13 @@ public final class TestUtil {
     return registry.getUnmodifiable();
   }
 
-  public static ExtensionRegistryLite getExtensionRegistryLite() {
-    ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
-    registerAllExtensionsLite(registry);
-    return registry.getUnmodifiable();
-  }
-
   /**
    * Register all of {@code TestAllExtensions}'s extensions with the
    * given {@link ExtensionRegistry}.
    */
   public static void registerAllExtensions(ExtensionRegistry registry) {
     UnittestProto.registerAllExtensions(registry);
-    registerAllExtensionsLite(registry);
-  }
-
-  public static void registerAllExtensionsLite(ExtensionRegistryLite registry) {
-    UnittestLite.registerAllExtensions(registry);
+    TestUtilLite.registerAllExtensionsLite(registry);
   }
 
   /**
@@ -2180,195 +1996,6 @@ public final class TestUtil {
   // Lite extensions
 
   /**
-   * Set every field of {@code message} to the values expected by
-   * {@code assertAllExtensionsSet()}.
-   */
-  public static void setAllExtensions(TestAllExtensionsLite.Builder message) {
-    message.setExtension(optionalInt32ExtensionLite   , 101);
-    message.setExtension(optionalInt64ExtensionLite   , 102L);
-    message.setExtension(optionalUint32ExtensionLite  , 103);
-    message.setExtension(optionalUint64ExtensionLite  , 104L);
-    message.setExtension(optionalSint32ExtensionLite  , 105);
-    message.setExtension(optionalSint64ExtensionLite  , 106L);
-    message.setExtension(optionalFixed32ExtensionLite , 107);
-    message.setExtension(optionalFixed64ExtensionLite , 108L);
-    message.setExtension(optionalSfixed32ExtensionLite, 109);
-    message.setExtension(optionalSfixed64ExtensionLite, 110L);
-    message.setExtension(optionalFloatExtensionLite   , 111F);
-    message.setExtension(optionalDoubleExtensionLite  , 112D);
-    message.setExtension(optionalBoolExtensionLite    , true);
-    message.setExtension(optionalStringExtensionLite  , "115");
-    message.setExtension(optionalBytesExtensionLite   , toBytes("116"));
-
-    message.setExtension(optionalGroupExtensionLite,
-      OptionalGroup_extension_lite.newBuilder().setA(117).build());
-    message.setExtension(optionalNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
-    message.setExtension(optionalForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(119).build());
-    message.setExtension(optionalImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(120).build());
-    message.setExtension(optionalPublicImportMessageExtensionLite,
-      PublicImportMessageLite.newBuilder().setE(126).build());
-    message.setExtension(optionalLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
-
-    message.setExtension(optionalNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
-    message.setExtension(optionalForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-    message.setExtension(optionalImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
-
-    message.setExtension(optionalStringPieceExtensionLite, "124");
-    message.setExtension(optionalCordExtensionLite, "125");
-
-    // -----------------------------------------------------------------
-
-    message.addExtension(repeatedInt32ExtensionLite   , 201);
-    message.addExtension(repeatedInt64ExtensionLite   , 202L);
-    message.addExtension(repeatedUint32ExtensionLite  , 203);
-    message.addExtension(repeatedUint64ExtensionLite  , 204L);
-    message.addExtension(repeatedSint32ExtensionLite  , 205);
-    message.addExtension(repeatedSint64ExtensionLite  , 206L);
-    message.addExtension(repeatedFixed32ExtensionLite , 207);
-    message.addExtension(repeatedFixed64ExtensionLite , 208L);
-    message.addExtension(repeatedSfixed32ExtensionLite, 209);
-    message.addExtension(repeatedSfixed64ExtensionLite, 210L);
-    message.addExtension(repeatedFloatExtensionLite   , 211F);
-    message.addExtension(repeatedDoubleExtensionLite  , 212D);
-    message.addExtension(repeatedBoolExtensionLite    , true);
-    message.addExtension(repeatedStringExtensionLite  , "215");
-    message.addExtension(repeatedBytesExtensionLite   , toBytes("216"));
-
-    message.addExtension(repeatedGroupExtensionLite,
-      RepeatedGroup_extension_lite.newBuilder().setA(217).build());
-    message.addExtension(repeatedNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
-    message.addExtension(repeatedForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(219).build());
-    message.addExtension(repeatedImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(220).build());
-    message.addExtension(repeatedLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
-
-    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAR);
-    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
-    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAR);
-
-    message.addExtension(repeatedStringPieceExtensionLite, "224");
-    message.addExtension(repeatedCordExtensionLite, "225");
-
-    // Add a second one of each field.
-    message.addExtension(repeatedInt32ExtensionLite   , 301);
-    message.addExtension(repeatedInt64ExtensionLite   , 302L);
-    message.addExtension(repeatedUint32ExtensionLite  , 303);
-    message.addExtension(repeatedUint64ExtensionLite  , 304L);
-    message.addExtension(repeatedSint32ExtensionLite  , 305);
-    message.addExtension(repeatedSint64ExtensionLite  , 306L);
-    message.addExtension(repeatedFixed32ExtensionLite , 307);
-    message.addExtension(repeatedFixed64ExtensionLite , 308L);
-    message.addExtension(repeatedSfixed32ExtensionLite, 309);
-    message.addExtension(repeatedSfixed64ExtensionLite, 310L);
-    message.addExtension(repeatedFloatExtensionLite   , 311F);
-    message.addExtension(repeatedDoubleExtensionLite  , 312D);
-    message.addExtension(repeatedBoolExtensionLite    , false);
-    message.addExtension(repeatedStringExtensionLite  , "315");
-    message.addExtension(repeatedBytesExtensionLite   , toBytes("316"));
-
-    message.addExtension(repeatedGroupExtensionLite,
-      RepeatedGroup_extension_lite.newBuilder().setA(317).build());
-    message.addExtension(repeatedNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
-    message.addExtension(repeatedForeignMessageExtensionLite,
-      ForeignMessageLite.newBuilder().setC(319).build());
-    message.addExtension(repeatedImportMessageExtensionLite,
-      ImportMessageLite.newBuilder().setD(320).build());
-    message.addExtension(repeatedLazyMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
-
-    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
-    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
-
-    message.addExtension(repeatedStringPieceExtensionLite, "324");
-    message.addExtension(repeatedCordExtensionLite, "325");
-
-    // -----------------------------------------------------------------
-
-    message.setExtension(defaultInt32ExtensionLite   , 401);
-    message.setExtension(defaultInt64ExtensionLite   , 402L);
-    message.setExtension(defaultUint32ExtensionLite  , 403);
-    message.setExtension(defaultUint64ExtensionLite  , 404L);
-    message.setExtension(defaultSint32ExtensionLite  , 405);
-    message.setExtension(defaultSint64ExtensionLite  , 406L);
-    message.setExtension(defaultFixed32ExtensionLite , 407);
-    message.setExtension(defaultFixed64ExtensionLite , 408L);
-    message.setExtension(defaultSfixed32ExtensionLite, 409);
-    message.setExtension(defaultSfixed64ExtensionLite, 410L);
-    message.setExtension(defaultFloatExtensionLite   , 411F);
-    message.setExtension(defaultDoubleExtensionLite  , 412D);
-    message.setExtension(defaultBoolExtensionLite    , false);
-    message.setExtension(defaultStringExtensionLite  , "415");
-    message.setExtension(defaultBytesExtensionLite   , toBytes("416"));
-
-    message.setExtension(defaultNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.FOO);
-    message.setExtension(defaultForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_FOO);
-    message.setExtension(defaultImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_FOO);
-
-    message.setExtension(defaultStringPieceExtensionLite, "424");
-    message.setExtension(defaultCordExtensionLite, "425");
-
-    message.setExtension(oneofUint32ExtensionLite, 601);
-    message.setExtension(oneofNestedMessageExtensionLite,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
-    message.setExtension(oneofStringExtensionLite, "603");
-    message.setExtension(oneofBytesExtensionLite, toBytes("604"));
-  }
-
-  // -------------------------------------------------------------------
-
-  /**
-   * Modify the repeated extensions of {@code message} to contain the values
-   * expected by {@code assertRepeatedExtensionsModified()}.
-   */
-  public static void modifyRepeatedExtensions(
-      TestAllExtensionsLite.Builder message) {
-    message.setExtension(repeatedInt32ExtensionLite   , 1, 501);
-    message.setExtension(repeatedInt64ExtensionLite   , 1, 502L);
-    message.setExtension(repeatedUint32ExtensionLite  , 1, 503);
-    message.setExtension(repeatedUint64ExtensionLite  , 1, 504L);
-    message.setExtension(repeatedSint32ExtensionLite  , 1, 505);
-    message.setExtension(repeatedSint64ExtensionLite  , 1, 506L);
-    message.setExtension(repeatedFixed32ExtensionLite , 1, 507);
-    message.setExtension(repeatedFixed64ExtensionLite , 1, 508L);
-    message.setExtension(repeatedSfixed32ExtensionLite, 1, 509);
-    message.setExtension(repeatedSfixed64ExtensionLite, 1, 510L);
-    message.setExtension(repeatedFloatExtensionLite   , 1, 511F);
-    message.setExtension(repeatedDoubleExtensionLite  , 1, 512D);
-    message.setExtension(repeatedBoolExtensionLite    , 1, true);
-    message.setExtension(repeatedStringExtensionLite  , 1, "515");
-    message.setExtension(repeatedBytesExtensionLite   , 1, toBytes("516"));
-
-    message.setExtension(repeatedGroupExtensionLite, 1,
-      RepeatedGroup_extension_lite.newBuilder().setA(517).build());
-    message.setExtension(repeatedNestedMessageExtensionLite, 1,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(518).build());
-    message.setExtension(repeatedForeignMessageExtensionLite, 1,
-      ForeignMessageLite.newBuilder().setC(519).build());
-    message.setExtension(repeatedImportMessageExtensionLite, 1,
-      ImportMessageLite.newBuilder().setD(520).build());
-    message.setExtension(repeatedLazyMessageExtensionLite, 1,
-      TestAllTypesLite.NestedMessage.newBuilder().setBb(527).build());
-
-    message.setExtension(repeatedNestedEnumExtensionLite , 1, TestAllTypesLite.NestedEnum.FOO);
-    message.setExtension(repeatedForeignEnumExtensionLite, 1, ForeignEnumLite.FOREIGN_LITE_FOO);
-    message.setExtension(repeatedImportEnumExtensionLite , 1, ImportEnumLite.IMPORT_LITE_FOO);
-
-    message.setExtension(repeatedStringPieceExtensionLite, 1, "524");
-    message.setExtension(repeatedCordExtensionLite, 1, "525");
-  }
-
-  // -------------------------------------------------------------------
-
-  /**
    * Assert (using {@code junit.framework.Assert}} that all extensions of
    * {@code message} are set to the values assigned by {@code setAllExtensions}.
    */
@@ -2867,38 +2494,6 @@ public final class TestUtil {
     assertEqualsExactType("525", message.getExtension(repeatedCordExtensionLite, 1));
   }
 
-  public static void setPackedExtensions(TestPackedExtensionsLite.Builder message) {
-    message.addExtension(packedInt32ExtensionLite   , 601);
-    message.addExtension(packedInt64ExtensionLite   , 602L);
-    message.addExtension(packedUint32ExtensionLite  , 603);
-    message.addExtension(packedUint64ExtensionLite  , 604L);
-    message.addExtension(packedSint32ExtensionLite  , 605);
-    message.addExtension(packedSint64ExtensionLite  , 606L);
-    message.addExtension(packedFixed32ExtensionLite , 607);
-    message.addExtension(packedFixed64ExtensionLite , 608L);
-    message.addExtension(packedSfixed32ExtensionLite, 609);
-    message.addExtension(packedSfixed64ExtensionLite, 610L);
-    message.addExtension(packedFloatExtensionLite   , 611F);
-    message.addExtension(packedDoubleExtensionLite  , 612D);
-    message.addExtension(packedBoolExtensionLite    , true);
-    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
-    // Add a second one of each field.
-    message.addExtension(packedInt32ExtensionLite   , 701);
-    message.addExtension(packedInt64ExtensionLite   , 702L);
-    message.addExtension(packedUint32ExtensionLite  , 703);
-    message.addExtension(packedUint64ExtensionLite  , 704L);
-    message.addExtension(packedSint32ExtensionLite  , 705);
-    message.addExtension(packedSint64ExtensionLite  , 706L);
-    message.addExtension(packedFixed32ExtensionLite , 707);
-    message.addExtension(packedFixed64ExtensionLite , 708L);
-    message.addExtension(packedSfixed32ExtensionLite, 709);
-    message.addExtension(packedSfixed64ExtensionLite, 710L);
-    message.addExtension(packedFloatExtensionLite   , 711F);
-    message.addExtension(packedDoubleExtensionLite  , 712D);
-    message.addExtension(packedBoolExtensionLite    , false);
-    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
-  }
-
   public static void assertPackedExtensionsSet(TestPackedExtensionsLite message) {
     Assert.assertEquals(2, message.getExtensionCount(packedInt32ExtensionLite   ));
     Assert.assertEquals(2, message.getExtensionCount(packedInt64ExtensionLite   ));
@@ -4250,7 +3845,7 @@ public final class TestUtil {
 
     private int invalidations;
 
-    //@Override (Java 1.6 override semantics, but we must support 1.5)
+    @Override
     public void markDirty() {
       invalidations++;
     }
diff --git a/java/core/src/test/java/com/google/protobuf/TestUtilLite.java b/java/core/src/test/java/com/google/protobuf/TestUtilLite.java
new file mode 100644
index 00000000..8f33fa14
--- /dev/null
+++ b/java/core/src/test/java/com/google/protobuf/TestUtilLite.java
@@ -0,0 +1,559 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import static com.google.protobuf.UnittestLite.OptionalGroup_extension_lite;
+import static com.google.protobuf.UnittestLite.RepeatedGroup_extension_lite;
+import static com.google.protobuf.UnittestLite.defaultBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultCordExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultStringExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.defaultUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofStringExtensionLite;
+import static com.google.protobuf.UnittestLite.oneofUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalCordExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalForeignMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalGroupExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalLazyMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalPublicImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalStringExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.optionalUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.packedDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.packedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.packedInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.packedUint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedBoolExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedBytesExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedCordExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedDoubleExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedFloatExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedForeignEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedForeignMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedGroupExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedImportEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedImportMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedInt32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedInt64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedLazyMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedNestedEnumExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedNestedMessageExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSfixed32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSfixed64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedSint64ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedStringExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedStringPieceExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedUint32ExtensionLite;
+import static com.google.protobuf.UnittestLite.repeatedUint64ExtensionLite;
+
+import com.google.protobuf.UnittestImportLite.ImportEnumLite;
+import com.google.protobuf.UnittestImportLite.ImportMessageLite;
+import com.google.protobuf.UnittestImportPublicLite.PublicImportMessageLite;
+import com.google.protobuf.UnittestLite.ForeignEnumLite;
+import com.google.protobuf.UnittestLite.ForeignMessageLite;
+import com.google.protobuf.UnittestLite.TestAllExtensionsLite;
+import com.google.protobuf.UnittestLite.TestAllTypesLite;
+import com.google.protobuf.UnittestLite.TestPackedExtensionsLite;
+
+/**
+ * Contains methods for setting fields of {@code TestAllTypesLite}, {@code TestAllExtensionsLite},
+ * and {@code TestPackedExtensionsLite}. This is analogous to the functionality in TestUtil.java but
+ * does not depend on the presence of any non-lite protos.
+ *
+ * <p>This code is not to be used outside of {@code com.google.protobuf} and
+ * subpackages.
+ */
+public final class TestUtilLite {
+  private TestUtilLite() {}
+
+  /** Helper to convert a String to ByteString. */
+  static ByteString toBytes(String str) {
+    return ByteString.copyFrom(str.getBytes(Internal.UTF_8));
+  }
+
+  /**
+   * Get a {@code TestAllTypesLite.Builder} with all fields set as they would be by
+   * {@link #setAllFields(TestAllTypesLite.Builder)}.
+   */
+  public static TestAllTypesLite.Builder getAllLiteSetBuilder() {
+    TestAllTypesLite.Builder builder = TestAllTypesLite.newBuilder();
+    setAllFields(builder);
+    return builder;
+  }
+
+  /**
+   * Get a {@code TestAllExtensionsLite} with all fields set as they would be by
+   * {@link #setAllExtensions(TestAllExtensionsLite.Builder)}.
+   */
+  public static TestAllExtensionsLite getAllLiteExtensionsSet() {
+    TestAllExtensionsLite.Builder builder = TestAllExtensionsLite.newBuilder();
+    setAllExtensions(builder);
+    return builder.build();
+  }
+
+  public static TestPackedExtensionsLite getLitePackedExtensionsSet() {
+    TestPackedExtensionsLite.Builder builder = TestPackedExtensionsLite.newBuilder();
+    setPackedExtensions(builder);
+    return builder.build();
+  }
+  
+  /**
+   * Set every field of {@code builder} to the values expected by
+   * {@code assertAllFieldsSet()}.
+   */
+  public static void setAllFields(TestAllTypesLite.Builder builder) {
+    builder.setOptionalInt32   (101);
+    builder.setOptionalInt64   (102);
+    builder.setOptionalUint32  (103);
+    builder.setOptionalUint64  (104);
+    builder.setOptionalSint32  (105);
+    builder.setOptionalSint64  (106);
+    builder.setOptionalFixed32 (107);
+    builder.setOptionalFixed64 (108);
+    builder.setOptionalSfixed32(109);
+    builder.setOptionalSfixed64(110);
+    builder.setOptionalFloat   (111);
+    builder.setOptionalDouble  (112);
+    builder.setOptionalBool    (true);
+    builder.setOptionalString  ("115");
+    builder.setOptionalBytes   (toBytes("116"));
+
+    builder.setOptionalGroup(
+        TestAllTypesLite.OptionalGroup.newBuilder().setA(117).build());
+    builder.setOptionalNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
+    builder.setOptionalForeignMessage(
+        ForeignMessageLite.newBuilder().setC(119).build());
+    builder.setOptionalImportMessage(
+        ImportMessageLite.newBuilder().setD(120).build());
+    builder.setOptionalPublicImportMessage(
+        PublicImportMessageLite.newBuilder().setE(126).build());
+    builder.setOptionalLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
+
+    builder.setOptionalNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
+    builder.setOptionalForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
+    builder.setOptionalImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
+
+    builder.setOptionalStringPiece("124");
+    builder.setOptionalCord("125");
+
+    // -----------------------------------------------------------------
+
+    builder.addRepeatedInt32   (201);
+    builder.addRepeatedInt64   (202);
+    builder.addRepeatedUint32  (203);
+    builder.addRepeatedUint64  (204);
+    builder.addRepeatedSint32  (205);
+    builder.addRepeatedSint64  (206);
+    builder.addRepeatedFixed32 (207);
+    builder.addRepeatedFixed64 (208);
+    builder.addRepeatedSfixed32(209);
+    builder.addRepeatedSfixed64(210);
+    builder.addRepeatedFloat   (211);
+    builder.addRepeatedDouble  (212);
+    builder.addRepeatedBool    (true);
+    builder.addRepeatedString  ("215");
+    builder.addRepeatedBytes   (toBytes("216"));
+
+    builder.addRepeatedGroup(
+        TestAllTypesLite.RepeatedGroup.newBuilder().setA(217).build());
+    builder.addRepeatedNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
+    builder.addRepeatedForeignMessage(
+        ForeignMessageLite.newBuilder().setC(219).build());
+    builder.addRepeatedImportMessage(
+        ImportMessageLite.newBuilder().setD(220).build());
+    builder.addRepeatedLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
+
+    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAR);
+    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAR);
+    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAR);
+
+    builder.addRepeatedStringPiece("224");
+    builder.addRepeatedCord("225");
+
+    // Add a second one of each field.
+    builder.addRepeatedInt32   (301);
+    builder.addRepeatedInt64   (302);
+    builder.addRepeatedUint32  (303);
+    builder.addRepeatedUint64  (304);
+    builder.addRepeatedSint32  (305);
+    builder.addRepeatedSint64  (306);
+    builder.addRepeatedFixed32 (307);
+    builder.addRepeatedFixed64 (308);
+    builder.addRepeatedSfixed32(309);
+    builder.addRepeatedSfixed64(310);
+    builder.addRepeatedFloat   (311);
+    builder.addRepeatedDouble  (312);
+    builder.addRepeatedBool    (false);
+    builder.addRepeatedString  ("315");
+    builder.addRepeatedBytes   (toBytes("316"));
+
+    builder.addRepeatedGroup(
+        TestAllTypesLite.RepeatedGroup.newBuilder().setA(317).build());
+    builder.addRepeatedNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
+    builder.addRepeatedForeignMessage(
+        ForeignMessageLite.newBuilder().setC(319).build());
+    builder.addRepeatedImportMessage(
+        ImportMessageLite.newBuilder().setD(320).build());
+    builder.addRepeatedLazyMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
+
+    builder.addRepeatedNestedEnum (TestAllTypesLite.NestedEnum.BAZ);
+    builder.addRepeatedForeignEnum(ForeignEnumLite.FOREIGN_LITE_BAZ);
+    builder.addRepeatedImportEnum (ImportEnumLite.IMPORT_LITE_BAZ);
+
+    builder.addRepeatedStringPiece("324");
+    builder.addRepeatedCord("325");
+
+    // -----------------------------------------------------------------
+
+    builder.setDefaultInt32   (401);
+    builder.setDefaultInt64   (402);
+    builder.setDefaultUint32  (403);
+    builder.setDefaultUint64  (404);
+    builder.setDefaultSint32  (405);
+    builder.setDefaultSint64  (406);
+    builder.setDefaultFixed32 (407);
+    builder.setDefaultFixed64 (408);
+    builder.setDefaultSfixed32(409);
+    builder.setDefaultSfixed64(410);
+    builder.setDefaultFloat   (411);
+    builder.setDefaultDouble  (412);
+    builder.setDefaultBool    (false);
+    builder.setDefaultString  ("415");
+    builder.setDefaultBytes   (toBytes("416"));
+
+    builder.setDefaultNestedEnum (TestAllTypesLite.NestedEnum.FOO);
+    builder.setDefaultForeignEnum(ForeignEnumLite.FOREIGN_LITE_FOO);
+    builder.setDefaultImportEnum (ImportEnumLite.IMPORT_LITE_FOO);
+
+    builder.setDefaultStringPiece("424");
+    builder.setDefaultCord("425");
+
+    builder.setOneofUint32(601);
+    builder.setOneofNestedMessage(
+        TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
+    builder.setOneofString("603");
+    builder.setOneofBytes(toBytes("604"));
+  }
+
+  /**
+   * Get an unmodifiable {@link ExtensionRegistryLite} containing all the
+   * extensions of {@code TestAllExtensionsLite}.
+   */
+  public static ExtensionRegistryLite getExtensionRegistryLite() {
+    ExtensionRegistryLite registry = ExtensionRegistryLite.newInstance();
+    registerAllExtensionsLite(registry);
+    return registry.getUnmodifiable();
+  }
+
+  /**
+   * Register all of {@code TestAllExtensionsLite}'s extensions with the
+   * given {@link ExtensionRegistryLite}.
+   */
+  public static void registerAllExtensionsLite(ExtensionRegistryLite registry) {
+    UnittestLite.registerAllExtensions(registry);
+  }
+
+  // ===================================================================
+  // Lite extensions
+
+  /**
+   * Set every field of {@code message} to the values expected by
+   * {@code assertAllExtensionsSet()}.
+   */
+  public static void setAllExtensions(TestAllExtensionsLite.Builder message) {
+    message.setExtension(optionalInt32ExtensionLite   , 101);
+    message.setExtension(optionalInt64ExtensionLite   , 102L);
+    message.setExtension(optionalUint32ExtensionLite  , 103);
+    message.setExtension(optionalUint64ExtensionLite  , 104L);
+    message.setExtension(optionalSint32ExtensionLite  , 105);
+    message.setExtension(optionalSint64ExtensionLite  , 106L);
+    message.setExtension(optionalFixed32ExtensionLite , 107);
+    message.setExtension(optionalFixed64ExtensionLite , 108L);
+    message.setExtension(optionalSfixed32ExtensionLite, 109);
+    message.setExtension(optionalSfixed64ExtensionLite, 110L);
+    message.setExtension(optionalFloatExtensionLite   , 111F);
+    message.setExtension(optionalDoubleExtensionLite  , 112D);
+    message.setExtension(optionalBoolExtensionLite    , true);
+    message.setExtension(optionalStringExtensionLite  , "115");
+    message.setExtension(optionalBytesExtensionLite   , toBytes("116"));
+
+    message.setExtension(optionalGroupExtensionLite,
+      OptionalGroup_extension_lite.newBuilder().setA(117).build());
+    message.setExtension(optionalNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(118).build());
+    message.setExtension(optionalForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(119).build());
+    message.setExtension(optionalImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(120).build());
+    message.setExtension(optionalPublicImportMessageExtensionLite,
+      PublicImportMessageLite.newBuilder().setE(126).build());
+    message.setExtension(optionalLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(127).build());
+
+    message.setExtension(optionalNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
+    message.setExtension(optionalForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+    message.setExtension(optionalImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
+
+    message.setExtension(optionalStringPieceExtensionLite, "124");
+    message.setExtension(optionalCordExtensionLite, "125");
+
+    // -----------------------------------------------------------------
+
+    message.addExtension(repeatedInt32ExtensionLite   , 201);
+    message.addExtension(repeatedInt64ExtensionLite   , 202L);
+    message.addExtension(repeatedUint32ExtensionLite  , 203);
+    message.addExtension(repeatedUint64ExtensionLite  , 204L);
+    message.addExtension(repeatedSint32ExtensionLite  , 205);
+    message.addExtension(repeatedSint64ExtensionLite  , 206L);
+    message.addExtension(repeatedFixed32ExtensionLite , 207);
+    message.addExtension(repeatedFixed64ExtensionLite , 208L);
+    message.addExtension(repeatedSfixed32ExtensionLite, 209);
+    message.addExtension(repeatedSfixed64ExtensionLite, 210L);
+    message.addExtension(repeatedFloatExtensionLite   , 211F);
+    message.addExtension(repeatedDoubleExtensionLite  , 212D);
+    message.addExtension(repeatedBoolExtensionLite    , true);
+    message.addExtension(repeatedStringExtensionLite  , "215");
+    message.addExtension(repeatedBytesExtensionLite   , toBytes("216"));
+
+    message.addExtension(repeatedGroupExtensionLite,
+      RepeatedGroup_extension_lite.newBuilder().setA(217).build());
+    message.addExtension(repeatedNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(218).build());
+    message.addExtension(repeatedForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(219).build());
+    message.addExtension(repeatedImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(220).build());
+    message.addExtension(repeatedLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(227).build());
+
+    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAR);
+    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
+    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAR);
+
+    message.addExtension(repeatedStringPieceExtensionLite, "224");
+    message.addExtension(repeatedCordExtensionLite, "225");
+
+    // Add a second one of each field.
+    message.addExtension(repeatedInt32ExtensionLite   , 301);
+    message.addExtension(repeatedInt64ExtensionLite   , 302L);
+    message.addExtension(repeatedUint32ExtensionLite  , 303);
+    message.addExtension(repeatedUint64ExtensionLite  , 304L);
+    message.addExtension(repeatedSint32ExtensionLite  , 305);
+    message.addExtension(repeatedSint64ExtensionLite  , 306L);
+    message.addExtension(repeatedFixed32ExtensionLite , 307);
+    message.addExtension(repeatedFixed64ExtensionLite , 308L);
+    message.addExtension(repeatedSfixed32ExtensionLite, 309);
+    message.addExtension(repeatedSfixed64ExtensionLite, 310L);
+    message.addExtension(repeatedFloatExtensionLite   , 311F);
+    message.addExtension(repeatedDoubleExtensionLite  , 312D);
+    message.addExtension(repeatedBoolExtensionLite    , false);
+    message.addExtension(repeatedStringExtensionLite  , "315");
+    message.addExtension(repeatedBytesExtensionLite   , toBytes("316"));
+
+    message.addExtension(repeatedGroupExtensionLite,
+      RepeatedGroup_extension_lite.newBuilder().setA(317).build());
+    message.addExtension(repeatedNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(318).build());
+    message.addExtension(repeatedForeignMessageExtensionLite,
+      ForeignMessageLite.newBuilder().setC(319).build());
+    message.addExtension(repeatedImportMessageExtensionLite,
+      ImportMessageLite.newBuilder().setD(320).build());
+    message.addExtension(repeatedLazyMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(327).build());
+
+    message.addExtension(repeatedNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.BAZ);
+    message.addExtension(repeatedForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+    message.addExtension(repeatedImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_BAZ);
+
+    message.addExtension(repeatedStringPieceExtensionLite, "324");
+    message.addExtension(repeatedCordExtensionLite, "325");
+
+    // -----------------------------------------------------------------
+
+    message.setExtension(defaultInt32ExtensionLite   , 401);
+    message.setExtension(defaultInt64ExtensionLite   , 402L);
+    message.setExtension(defaultUint32ExtensionLite  , 403);
+    message.setExtension(defaultUint64ExtensionLite  , 404L);
+    message.setExtension(defaultSint32ExtensionLite  , 405);
+    message.setExtension(defaultSint64ExtensionLite  , 406L);
+    message.setExtension(defaultFixed32ExtensionLite , 407);
+    message.setExtension(defaultFixed64ExtensionLite , 408L);
+    message.setExtension(defaultSfixed32ExtensionLite, 409);
+    message.setExtension(defaultSfixed64ExtensionLite, 410L);
+    message.setExtension(defaultFloatExtensionLite   , 411F);
+    message.setExtension(defaultDoubleExtensionLite  , 412D);
+    message.setExtension(defaultBoolExtensionLite    , false);
+    message.setExtension(defaultStringExtensionLite  , "415");
+    message.setExtension(defaultBytesExtensionLite   , toBytes("416"));
+
+    message.setExtension(defaultNestedEnumExtensionLite, TestAllTypesLite.NestedEnum.FOO);
+    message.setExtension(defaultForeignEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_FOO);
+    message.setExtension(defaultImportEnumExtensionLite, ImportEnumLite.IMPORT_LITE_FOO);
+
+    message.setExtension(defaultStringPieceExtensionLite, "424");
+    message.setExtension(defaultCordExtensionLite, "425");
+
+    message.setExtension(oneofUint32ExtensionLite, 601);
+    message.setExtension(oneofNestedMessageExtensionLite,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(602).build());
+    message.setExtension(oneofStringExtensionLite, "603");
+    message.setExtension(oneofBytesExtensionLite, toBytes("604"));
+  }
+
+  // -------------------------------------------------------------------
+
+  /**
+   * Modify the repeated extensions of {@code message} to contain the values
+   * expected by {@code assertRepeatedExtensionsModified()}.
+   */
+  public static void modifyRepeatedExtensions(
+      TestAllExtensionsLite.Builder message) {
+    message.setExtension(repeatedInt32ExtensionLite   , 1, 501);
+    message.setExtension(repeatedInt64ExtensionLite   , 1, 502L);
+    message.setExtension(repeatedUint32ExtensionLite  , 1, 503);
+    message.setExtension(repeatedUint64ExtensionLite  , 1, 504L);
+    message.setExtension(repeatedSint32ExtensionLite  , 1, 505);
+    message.setExtension(repeatedSint64ExtensionLite  , 1, 506L);
+    message.setExtension(repeatedFixed32ExtensionLite , 1, 507);
+    message.setExtension(repeatedFixed64ExtensionLite , 1, 508L);
+    message.setExtension(repeatedSfixed32ExtensionLite, 1, 509);
+    message.setExtension(repeatedSfixed64ExtensionLite, 1, 510L);
+    message.setExtension(repeatedFloatExtensionLite   , 1, 511F);
+    message.setExtension(repeatedDoubleExtensionLite  , 1, 512D);
+    message.setExtension(repeatedBoolExtensionLite    , 1, true);
+    message.setExtension(repeatedStringExtensionLite  , 1, "515");
+    message.setExtension(repeatedBytesExtensionLite   , 1, toBytes("516"));
+
+    message.setExtension(repeatedGroupExtensionLite, 1,
+      RepeatedGroup_extension_lite.newBuilder().setA(517).build());
+    message.setExtension(repeatedNestedMessageExtensionLite, 1,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(518).build());
+    message.setExtension(repeatedForeignMessageExtensionLite, 1,
+      ForeignMessageLite.newBuilder().setC(519).build());
+    message.setExtension(repeatedImportMessageExtensionLite, 1,
+      ImportMessageLite.newBuilder().setD(520).build());
+    message.setExtension(repeatedLazyMessageExtensionLite, 1,
+      TestAllTypesLite.NestedMessage.newBuilder().setBb(527).build());
+
+    message.setExtension(repeatedNestedEnumExtensionLite , 1, TestAllTypesLite.NestedEnum.FOO);
+    message.setExtension(repeatedForeignEnumExtensionLite, 1, ForeignEnumLite.FOREIGN_LITE_FOO);
+    message.setExtension(repeatedImportEnumExtensionLite , 1, ImportEnumLite.IMPORT_LITE_FOO);
+
+    message.setExtension(repeatedStringPieceExtensionLite, 1, "524");
+    message.setExtension(repeatedCordExtensionLite, 1, "525");
+  }
+
+  public static void setPackedExtensions(TestPackedExtensionsLite.Builder message) {
+    message.addExtension(packedInt32ExtensionLite   , 601);
+    message.addExtension(packedInt64ExtensionLite   , 602L);
+    message.addExtension(packedUint32ExtensionLite  , 603);
+    message.addExtension(packedUint64ExtensionLite  , 604L);
+    message.addExtension(packedSint32ExtensionLite  , 605);
+    message.addExtension(packedSint64ExtensionLite  , 606L);
+    message.addExtension(packedFixed32ExtensionLite , 607);
+    message.addExtension(packedFixed64ExtensionLite , 608L);
+    message.addExtension(packedSfixed32ExtensionLite, 609);
+    message.addExtension(packedSfixed64ExtensionLite, 610L);
+    message.addExtension(packedFloatExtensionLite   , 611F);
+    message.addExtension(packedDoubleExtensionLite  , 612D);
+    message.addExtension(packedBoolExtensionLite    , true);
+    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAR);
+    // Add a second one of each field.
+    message.addExtension(packedInt32ExtensionLite   , 701);
+    message.addExtension(packedInt64ExtensionLite   , 702L);
+    message.addExtension(packedUint32ExtensionLite  , 703);
+    message.addExtension(packedUint64ExtensionLite  , 704L);
+    message.addExtension(packedSint32ExtensionLite  , 705);
+    message.addExtension(packedSint64ExtensionLite  , 706L);
+    message.addExtension(packedFixed32ExtensionLite , 707);
+    message.addExtension(packedFixed64ExtensionLite , 708L);
+    message.addExtension(packedSfixed32ExtensionLite, 709);
+    message.addExtension(packedSfixed64ExtensionLite, 710L);
+    message.addExtension(packedFloatExtensionLite   , 711F);
+    message.addExtension(packedDoubleExtensionLite  , 712D);
+    message.addExtension(packedBoolExtensionLite    , false);
+    message.addExtension(packedEnumExtensionLite, ForeignEnumLite.FOREIGN_LITE_BAZ);
+  }
+}
diff --git a/java/core/src/test/java/com/google/protobuf/TextFormatTest.java b/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
index 3f47d924..63c17cd0 100644
--- a/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/TextFormatTest.java
@@ -775,11 +775,14 @@ public class TextFormatTest extends TestCase {
   public void testParseBoolean() throws Exception {
     String goodText =
         "repeated_bool: t  repeated_bool : 0\n" +
-        "repeated_bool :f repeated_bool:1";
+        "repeated_bool :f repeated_bool:1\n" +
+        "repeated_bool: False repeated_bool: True";
     String goodTextCanonical =
         "repeated_bool: true\n" +
         "repeated_bool: false\n" +
         "repeated_bool: false\n" +
+        "repeated_bool: true\n" +
+        "repeated_bool: false\n" +
         "repeated_bool: true\n";
     TestAllTypes.Builder builder = TestAllTypes.newBuilder();
     TextFormat.merge(goodText, builder);
diff --git a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
index 8c9dcafe..32380f70 100644
--- a/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
+++ b/java/core/src/test/java/com/google/protobuf/UnknownFieldSetTest.java
@@ -50,6 +50,7 @@ import java.util.Map;
  * @author kenton@google.com (Kenton Varda)
  */
 public class UnknownFieldSetTest extends TestCase {
+  @Override
   public void setUp() throws Exception {
     descriptor = TestAllTypes.getDescriptor();
     allFields = TestUtil.getAllSet();
diff --git a/java/core/src/test/java/com/google/protobuf/WireFormatTest.java b/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
index b3aabb8f..e66b371c 100644
--- a/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
+++ b/java/core/src/test/java/com/google/protobuf/WireFormatTest.java
@@ -132,7 +132,7 @@ public class WireFormatTest extends TestCase {
     // so if we serialize a TestAllExtensions then parse it as TestAllTypes
     // it should work.
 
-    TestAllExtensionsLite message = TestUtil.getAllLiteExtensionsSet();
+    TestAllExtensionsLite message = TestUtilLite.getAllLiteExtensionsSet();
     ByteString rawBytes = message.toByteString();
     assertEquals(rawBytes.size(), message.getSerializedSize());
 
@@ -144,7 +144,7 @@ public class WireFormatTest extends TestCase {
   public void testSerializePackedExtensionsLite() throws Exception {
     // TestPackedTypes and TestPackedExtensions should have compatible wire
     // formats; check that they serialize to the same string.
-    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite message = TestUtilLite.getLitePackedExtensionsSet();
     ByteString rawBytes = message.toByteString();
 
     TestPackedTypes message2 = TestUtil.getPackedSet();
@@ -190,7 +190,7 @@ public class WireFormatTest extends TestCase {
     TestAllTypes message = TestUtil.getAllSet();
     ByteString rawBytes = message.toByteString();
 
-    ExtensionRegistryLite registry_lite = TestUtil.getExtensionRegistryLite();
+    ExtensionRegistryLite registry_lite = TestUtilLite.getExtensionRegistryLite();
 
     TestAllExtensionsLite message2 =
       TestAllExtensionsLite.parseFrom(rawBytes, registry_lite);
@@ -208,10 +208,10 @@ public class WireFormatTest extends TestCase {
 
   public void testParsePackedExtensionsLite() throws Exception {
     // Ensure that packed extensions can be properly parsed.
-    TestPackedExtensionsLite message = TestUtil.getLitePackedExtensionsSet();
+    TestPackedExtensionsLite message = TestUtilLite.getLitePackedExtensionsSet();
     ByteString rawBytes = message.toByteString();
 
-    ExtensionRegistryLite registry = TestUtil.getExtensionRegistryLite();
+    ExtensionRegistryLite registry = TestUtilLite.getExtensionRegistryLite();
 
     TestPackedExtensionsLite message2 =
         TestPackedExtensionsLite.parseFrom(rawBytes, registry);
diff --git a/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto b/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
index f75484de..6eef42c5 100644
--- a/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
+++ b/java/core/src/test/proto/com/google/protobuf/lite_equals_and_hash.proto
@@ -34,9 +34,6 @@ syntax = "proto2";
 
 package protobuf_unittest.lite_equals_and_hash;
 
-// This proto definition is used to test that java_generate_equals_and_hash
-// works correctly with the LITE_RUNTIME.
-option java_generate_equals_and_hash = true;
 option optimize_for = LITE_RUNTIME;
 
 message TestOneofEquals {
diff --git a/java/lite/generate-sources-build.xml b/java/lite/generate-sources-build.xml
new file mode 100644
index 00000000..89c21c13
--- /dev/null
+++ b/java/lite/generate-sources-build.xml
@@ -0,0 +1,20 @@
+<project name="generate-sources">
+    <echo message="Running protoc ..."/>
+    <mkdir dir="${generated.sources.lite.dir}"/>
+    <exec executable="${protoc}">
+        <arg value="--java_out=lite:${generated.sources.lite.dir}"/>
+        <arg value="--proto_path=${protobuf.source.dir}"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/any.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/api.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/descriptor.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/duration.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/empty.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/field_mask.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/source_context.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/struct.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/timestamp.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/type.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/wrappers.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/compiler/plugin.proto"/>
+    </exec>
+</project>
diff --git a/java/lite/generate-test-sources-build.xml b/java/lite/generate-test-sources-build.xml
new file mode 100644
index 00000000..cdd1ee89
--- /dev/null
+++ b/java/lite/generate-test-sources-build.xml
@@ -0,0 +1,43 @@
+<project name="generate-test-sources">
+    <mkdir dir="${generated.testsources.lite.dir}"/>
+    <exec executable="${protoc}">
+        <arg value="--java_out=lite:${generated.testsources.lite.dir}"/>
+        <arg value="--proto_path=${protobuf.source.dir}"/>
+        <arg value="--proto_path=${test.proto.dir}"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import_public.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_mset.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_mset_wire_format.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_optimize_for.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_custom_options.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_lite.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import_lite.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import_public_lite.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_lite_imports_nonlite.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_enormous_descriptor.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_no_generic_services.proto"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/unittest_well_known_types.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/lazy_fields_lite.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/lite_equals_and_hash.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/multiple_files_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/nested_builders_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/nested_extension.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/nested_extension_lite.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/non_nested_extension.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/non_nested_extension_lite.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/outer_class_name_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/outer_class_name_test2.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/outer_class_name_test3.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/test_bad_identifiers.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/test_check_utf8.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/test_check_utf8_size.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/test_custom_options.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/any_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/field_presence_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/map_for_proto2_lite_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/map_for_proto2_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/map_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/map_initialization_order_test.proto"/>
+    </exec>
+</project>
diff --git a/java/lite/pom.xml b/java/lite/pom.xml
index 70c7d047..23cb4f78 100644
--- a/java/lite/pom.xml
+++ b/java/lite/pom.xml
@@ -50,7 +50,7 @@
             <phase>generate-sources</phase>
             <configuration>
               <target>
-                <ant antfile="${core.root}/generate-sources-build.xml"/>
+                <ant antfile="generate-sources-build.xml"/>
               </target>
             </configuration>
             <goals>
@@ -64,7 +64,7 @@
             <phase>generate-test-sources</phase>
             <configuration>
               <target>
-                <ant antfile="${core.root}/generate-test-sources-build.xml"/>
+                <ant antfile="generate-test-sources-build.xml"/>
               </target>
             </configuration>
             <goals>
@@ -78,8 +78,8 @@
       <plugin>
         <artifactId>maven-compiler-plugin</artifactId>
         <configuration>
-          <generatedSourcesDirectory>${generated.sources.dir}</generatedSourcesDirectory>
-          <generatedTestSourcesDirectory>${generated.testsources.dir}</generatedTestSourcesDirectory>
+          <generatedSourcesDirectory>${generated.sources.lite.dir}</generatedSourcesDirectory>
+          <generatedTestSourcesDirectory>${generated.testsources.lite.dir}</generatedTestSourcesDirectory>
           <includes>
             <include>**/AbstractMessageLite.java</include>
             <include>**/AbstractParser.java</include>
diff --git a/java/pom.xml b/java/pom.xml
index 787bc534..e8dc5ded 100644
--- a/java/pom.xml
+++ b/java/pom.xml
@@ -33,6 +33,8 @@
     <test.proto.dir>src/test/proto</test.proto.dir>
     <generated.sources.dir>${project.build.directory}/generated-sources</generated.sources.dir>
     <generated.testsources.dir>${project.build.directory}/generated-test-sources</generated.testsources.dir>
+    <generated.sources.lite.dir>${project.build.directory}/generated-sources-lite</generated.sources.lite.dir>
+    <generated.testsources.lite.dir>${project.build.directory}/generated-test-sources-lite</generated.testsources.lite.dir>
   </properties>
 
   <licenses>
diff --git a/java/src/main/java/com/google/protobuf/AbstractMessage.java b/java/src/main/java/com/google/protobuf/AbstractMessage.java
new file mode 100644
index 00000000..03c0d579
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/AbstractMessage.java
@@ -0,0 +1,553 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import com.google.protobuf.Descriptors.EnumValueDescriptor;
+import com.google.protobuf.Descriptors.FieldDescriptor;
+import com.google.protobuf.Descriptors.OneofDescriptor;
+import com.google.protobuf.Internal.EnumLite;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * A partial implementation of the {@link Message} interface which implements
+ * as many methods of that interface as possible in terms of other methods.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public abstract class AbstractMessage
+    // TODO(dweis): Update GeneratedMessage to parameterize with MessageType and BuilderType.
+    extends AbstractMessageLite
+    implements Message {
+  
+  @Override
+  public boolean isInitialized() {
+    return MessageReflection.isInitialized(this);
+  }
+
+
+  @Override
+  public List<String> findInitializationErrors() {
+    return MessageReflection.findMissingFields(this);
+  }
+
+  @Override
+  public String getInitializationErrorString() {
+    return MessageReflection.delimitWithCommas(findInitializationErrors());
+  }
+
+  /** TODO(jieluo): Clear it when all subclasses have implemented this method. */
+  @Override
+  public boolean hasOneof(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException("hasOneof() is not implemented.");
+  }
+
+  /** TODO(jieluo): Clear it when all subclasses have implemented this method. */
+  @Override
+  public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+    throw new UnsupportedOperationException(
+        "getOneofFieldDescriptor() is not implemented.");
+  }
+
+  @Override
+  public final String toString() {
+    return TextFormat.printToString(this);
+  }
+
+  @Override
+  public void writeTo(final CodedOutputStream output) throws IOException {
+    MessageReflection.writeMessageTo(this, getAllFields(), output, false);
+  }
+
+  protected int memoizedSize = -1;
+
+  @Override
+  public int getSerializedSize() {
+    int size = memoizedSize;
+    if (size != -1) {
+      return size;
+    }
+
+    memoizedSize = MessageReflection.getSerializedSize(this, getAllFields());
+    return memoizedSize;
+  }
+
+  @Override
+  public boolean equals(final Object other) {
+    if (other == this) {
+      return true;
+    }
+    if (!(other instanceof Message)) {
+      return false;
+    }
+    final Message otherMessage = (Message) other;
+    if (getDescriptorForType() != otherMessage.getDescriptorForType()) {
+      return false;
+    }
+    return compareFields(getAllFields(), otherMessage.getAllFields()) &&
+        getUnknownFields().equals(otherMessage.getUnknownFields());
+  }
+
+  @Override
+  public int hashCode() {
+    int hash = memoizedHashCode;
+    if (hash == 0) {
+      hash = 41;
+      hash = (19 * hash) + getDescriptorForType().hashCode();
+      hash = hashFields(hash, getAllFields());
+      hash = (29 * hash) + getUnknownFields().hashCode();
+      memoizedHashCode = hash;
+    }
+    return hash;
+  }
+  
+  private static ByteString toByteString(Object value) {
+    if (value instanceof byte[]) {
+      return ByteString.copyFrom((byte[]) value);
+    } else {
+      return (ByteString) value;
+    }
+  }
+ 
+  /**
+   * Compares two bytes fields. The parameters must be either a byte array or a
+   * ByteString object. They can be of different type though.
+   */
+  private static boolean compareBytes(Object a, Object b) {
+    if (a instanceof byte[] && b instanceof byte[]) {
+      return Arrays.equals((byte[])a, (byte[])b);
+    }
+    return toByteString(a).equals(toByteString(b));
+  }
+  
+  /**
+   * Converts a list of MapEntry messages into a Map used for equals() and
+   * hashCode().
+   */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static Map convertMapEntryListToMap(List list) {
+    if (list.isEmpty()) {
+      return Collections.emptyMap();
+    }
+    Map result = new HashMap();
+    Iterator iterator = list.iterator();
+    Message entry = (Message) iterator.next();
+    Descriptors.Descriptor descriptor = entry.getDescriptorForType();
+    Descriptors.FieldDescriptor key = descriptor.findFieldByName("key");
+    Descriptors.FieldDescriptor value = descriptor.findFieldByName("value");
+    Object fieldValue = entry.getField(value);
+    if (fieldValue instanceof EnumValueDescriptor) {
+      fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+    }
+    result.put(entry.getField(key), fieldValue);
+    while (iterator.hasNext()) {
+      entry = (Message) iterator.next();
+      fieldValue = entry.getField(value);
+      if (fieldValue instanceof EnumValueDescriptor) {
+        fieldValue = ((EnumValueDescriptor) fieldValue).getNumber();
+      }
+      result.put(entry.getField(key), fieldValue);
+    }
+    return result;
+  }
+  
+  /**
+   * Compares two map fields. The parameters must be a list of MapEntry
+   * messages.
+   */
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static boolean compareMapField(Object a, Object b) {
+    Map ma = convertMapEntryListToMap((List) a);
+    Map mb = convertMapEntryListToMap((List) b);
+    return MapFieldLite.equals(ma, mb);
+  }
+  
+  /**
+   * Compares two set of fields.
+   * This method is used to implement {@link AbstractMessage#equals(Object)}
+   * and {@link AbstractMutableMessage#equals(Object)}. It takes special care
+   * of bytes fields because immutable messages and mutable messages use
+   * different Java type to reprensent a bytes field and this method should be
+   * able to compare immutable messages, mutable messages and also an immutable
+   * message to a mutable message.
+   */
+  static boolean compareFields(Map<FieldDescriptor, Object> a,
+      Map<FieldDescriptor, Object> b) {
+    if (a.size() != b.size()) {
+      return false;
+    }
+    for (FieldDescriptor descriptor : a.keySet()) {
+      if (!b.containsKey(descriptor)) {
+        return false;
+      }
+      Object value1 = a.get(descriptor);
+      Object value2 = b.get(descriptor);
+      if (descriptor.getType() == FieldDescriptor.Type.BYTES) {
+        if (descriptor.isRepeated()) {
+          List list1 = (List) value1;
+          List list2 = (List) value2;
+          if (list1.size() != list2.size()) {
+            return false;
+          }
+          for (int i = 0; i < list1.size(); i++) {
+            if (!compareBytes(list1.get(i), list2.get(i))) {
+              return false;
+            }
+          }
+        } else {
+          // Compares a singular bytes field.
+          if (!compareBytes(value1, value2)) {
+            return false;
+          }
+        }
+      } else if (descriptor.isMapField()) {
+        if (!compareMapField(value1, value2)) {
+          return false;
+        }
+      } else {
+        // Compare non-bytes fields.
+        if (!value1.equals(value2)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+  
+  /**
+   * Calculates the hash code of a map field. {@code value} must be a list of
+   * MapEntry messages.
+   */
+  @SuppressWarnings("unchecked")
+  private static int hashMapField(Object value) {
+    return MapFieldLite.calculateHashCodeForMap(convertMapEntryListToMap((List) value));
+  }
+
+  /** Get a hash code for given fields and values, using the given seed. */
+  @SuppressWarnings("unchecked")
+  protected static int hashFields(int hash, Map<FieldDescriptor, Object> map) {
+    for (Map.Entry<FieldDescriptor, Object> entry : map.entrySet()) {
+      FieldDescriptor field = entry.getKey();
+      Object value = entry.getValue();
+      hash = (37 * hash) + field.getNumber();
+      if (field.isMapField()) {
+        hash = (53 * hash) + hashMapField(value);
+      } else if (field.getType() != FieldDescriptor.Type.ENUM){
+        hash = (53 * hash) + value.hashCode();
+      } else if (field.isRepeated()) {
+        List<? extends EnumLite> list = (List<? extends EnumLite>) value;
+        hash = (53 * hash) + Internal.hashEnumList(list);
+      } else {
+        hash = (53 * hash) + Internal.hashEnum((EnumLite) value);
+      }
+    }
+    return hash;
+  }
+
+  /**
+   * Package private helper method for AbstractParser to create
+   * UninitializedMessageException with missing field information.
+   */
+  @Override
+  UninitializedMessageException newUninitializedMessageException() {
+    return Builder.newUninitializedMessageException(this);
+  }
+
+  // =================================================================
+
+  /**
+   * A partial implementation of the {@link Message.Builder} interface which
+   * implements as many methods of that interface as possible in terms of
+   * other methods.
+   */
+  @SuppressWarnings("unchecked")
+  public static abstract class Builder<BuilderType extends Builder<BuilderType>>
+      extends AbstractMessageLite.Builder
+      implements Message.Builder {
+    // The compiler produces an error if this is not declared explicitly.
+    @Override
+    public abstract BuilderType clone();
+
+    /** TODO(jieluo): Clear it when all subclasses have implemented this method. */
+    @Override
+    public boolean hasOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("hasOneof() is not implemented.");
+    }
+
+    /** TODO(jieluo): Clear it when all subclasses have implemented this method. */
+    @Override
+    public FieldDescriptor getOneofFieldDescriptor(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException(
+          "getOneofFieldDescriptor() is not implemented.");
+    }
+
+    /** TODO(jieluo): Clear it when all subclasses have implemented this method. */
+    @Override
+    public BuilderType clearOneof(OneofDescriptor oneof) {
+      throw new UnsupportedOperationException("clearOneof() is not implemented.");
+    }
+
+    @Override
+    public BuilderType clear() {
+      for (final Map.Entry<FieldDescriptor, Object> entry :
+           getAllFields().entrySet()) {
+        clearField(entry.getKey());
+      }
+      return (BuilderType) this;
+    }
+
+    @Override
+    public List<String> findInitializationErrors() {
+      return MessageReflection.findMissingFields(this);
+    }
+
+    @Override
+    public String getInitializationErrorString() {
+      return MessageReflection.delimitWithCommas(findInitializationErrors());
+    }
+    
+    @Override
+    protected BuilderType internalMergeFrom(AbstractMessageLite other) {
+      return mergeFrom((Message) other);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final Message other) {
+      if (other.getDescriptorForType() != getDescriptorForType()) {
+        throw new IllegalArgumentException(
+          "mergeFrom(Message) can only merge messages of the same type.");
+      }
+
+      // Note:  We don't attempt to verify that other's fields have valid
+      //   types.  Doing so would be a losing battle.  We'd have to verify
+      //   all sub-messages as well, and we'd have to make copies of all of
+      //   them to insure that they don't change after verification (since
+      //   the Message interface itself cannot enforce immutability of
+      //   implementations).
+      // TODO(kenton):  Provide a function somewhere called makeDeepCopy()
+      //   which allows people to make secure deep copies of messages.
+
+      for (final Map.Entry<FieldDescriptor, Object> entry :
+           other.getAllFields().entrySet()) {
+        final FieldDescriptor field = entry.getKey();
+        if (field.isRepeated()) {
+          for (final Object element : (List)entry.getValue()) {
+            addRepeatedField(field, element);
+          }
+        } else if (field.getJavaType() == FieldDescriptor.JavaType.MESSAGE) {
+          final Message existingValue = (Message)getField(field);
+          if (existingValue == existingValue.getDefaultInstanceForType()) {
+            setField(field, entry.getValue());
+          } else {
+            setField(field,
+              existingValue.newBuilderForType()
+                .mergeFrom(existingValue)
+                .mergeFrom((Message)entry.getValue())
+                .build());
+          }
+        } else {
+          setField(field, entry.getValue());
+        }
+      }
+
+      mergeUnknownFields(other.getUnknownFields());
+
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input)
+                                 throws IOException {
+      return mergeFrom(input, ExtensionRegistry.getEmptyRegistry());
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final CodedInputStream input,
+        final ExtensionRegistryLite extensionRegistry)
+        throws IOException {
+      final UnknownFieldSet.Builder unknownFields =
+        UnknownFieldSet.newBuilder(getUnknownFields());
+      while (true) {
+        final int tag = input.readTag();
+        if (tag == 0) {
+          break;
+        }
+
+        MessageReflection.BuilderAdapter builderAdapter =
+            new MessageReflection.BuilderAdapter(this);
+        if (!MessageReflection.mergeFieldFrom(input, unknownFields,
+                                              extensionRegistry,
+                                              getDescriptorForType(),
+                                              builderAdapter,
+                                              tag)) {
+          // end group tag
+          break;
+        }
+      }
+      setUnknownFields(unknownFields.build());
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeUnknownFields(final UnknownFieldSet unknownFields) {
+      setUnknownFields(
+        UnknownFieldSet.newBuilder(getUnknownFields())
+                       .mergeFrom(unknownFields)
+                       .build());
+      return (BuilderType) this;
+    }
+
+    @Override
+    public Message.Builder getFieldBuilder(final FieldDescriptor field) {
+      throw new UnsupportedOperationException(
+          "getFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public Message.Builder getRepeatedFieldBuilder(final FieldDescriptor field, int index) {
+      throw new UnsupportedOperationException(
+          "getRepeatedFieldBuilder() called on an unsupported message type.");
+    }
+
+    @Override
+    public String toString() {
+      return TextFormat.printToString(this);
+    }
+
+    /**
+     * Construct an UninitializedMessageException reporting missing fields in
+     * the given message.
+     */
+    protected static UninitializedMessageException
+        newUninitializedMessageException(Message message) {
+      return new UninitializedMessageException(
+          MessageReflection.findMissingFields(message));
+    }
+
+    // ===============================================================
+    // The following definitions seem to be required in order to make javac
+    // not produce weird errors like:
+    //
+    // java/com/google/protobuf/DynamicMessage.java:203: types
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> and
+    //   com.google.protobuf.AbstractMessage.Builder<
+    //     com.google.protobuf.DynamicMessage.Builder> are incompatible; both
+    //   define mergeFrom(com.google.protobuf.ByteString), but with unrelated
+    //   return types.
+    //
+    // Strangely, these lines are only needed if javac is invoked separately
+    // on AbstractMessage.java and AbstractMessageLite.java.  If javac is
+    // invoked on both simultaneously, it works.  (Or maybe the important
+    // point is whether or not DynamicMessage.java is compiled together with
+    // AbstractMessageLite.java -- not sure.)  I suspect this is a compiler
+    // bug.
+
+    @Override
+    public BuilderType mergeFrom(final ByteString data)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final ByteString data,
+        final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final byte[] data, final int off, final int len)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, off, len);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final byte[] data,
+        final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final byte[] data, final int off, final int len,
+        final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return (BuilderType) super.mergeFrom(data, off, len, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final InputStream input)
+        throws IOException {
+      return (BuilderType) super.mergeFrom(input);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final InputStream input,
+        final ExtensionRegistryLite extensionRegistry)
+        throws IOException {
+      return (BuilderType) super.mergeFrom(input, extensionRegistry);
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input)
+        throws IOException {
+      return super.mergeDelimitedFrom(input);
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(
+        final InputStream input,
+        final ExtensionRegistryLite extensionRegistry)
+        throws IOException {
+      return super.mergeDelimitedFrom(input, extensionRegistry);
+    }
+  }
+}
diff --git a/java/src/main/java/com/google/protobuf/AbstractMessageLite.java b/java/src/main/java/com/google/protobuf/AbstractMessageLite.java
new file mode 100644
index 00000000..43736dd1
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/AbstractMessageLite.java
@@ -0,0 +1,386 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import java.io.FilterInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Collection;
+
+/**
+ * A partial implementation of the {@link MessageLite} interface which
+ * implements as many methods of that interface as possible in terms of other
+ * methods.
+ *
+ * @author kenton@google.com Kenton Varda
+ */
+public abstract class AbstractMessageLite<
+    MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+    BuilderType extends AbstractMessageLite.Builder<MessageType, BuilderType>> 
+        implements MessageLite {
+  protected int memoizedHashCode = 0;
+  
+  @Override
+  public ByteString toByteString() {
+    try {
+      final ByteString.CodedBuilder out =
+        ByteString.newCodedBuilder(getSerializedSize());
+      writeTo(out.getCodedOutput());
+      return out.build();
+    } catch (IOException e) {
+      throw new RuntimeException(
+        "Serializing to a ByteString threw an IOException (should " +
+        "never happen).", e);
+    }
+  }
+
+  @Override
+  public byte[] toByteArray() {
+    try {
+      final byte[] result = new byte[getSerializedSize()];
+      final CodedOutputStream output = CodedOutputStream.newInstance(result);
+      writeTo(output);
+      output.checkNoSpaceLeft();
+      return result;
+    } catch (IOException e) {
+      throw new RuntimeException(
+        "Serializing to a byte array threw an IOException " +
+        "(should never happen).", e);
+    }
+  }
+
+  @Override
+  public void writeTo(final OutputStream output) throws IOException {
+    final int bufferSize =
+        CodedOutputStream.computePreferredBufferSize(getSerializedSize());
+    final CodedOutputStream codedOutput =
+        CodedOutputStream.newInstance(output, bufferSize);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+  @Override
+  public void writeDelimitedTo(final OutputStream output) throws IOException {
+    final int serialized = getSerializedSize();
+    final int bufferSize = CodedOutputStream.computePreferredBufferSize(
+        CodedOutputStream.computeRawVarint32Size(serialized) + serialized);
+    final CodedOutputStream codedOutput =
+        CodedOutputStream.newInstance(output, bufferSize);
+    codedOutput.writeRawVarint32(serialized);
+    writeTo(codedOutput);
+    codedOutput.flush();
+  }
+
+
+  /**
+   * Package private helper method for AbstractParser to create
+   * UninitializedMessageException.
+   */
+  UninitializedMessageException newUninitializedMessageException() {
+    return new UninitializedMessageException(this);
+  }
+
+  protected static void checkByteStringIsUtf8(ByteString byteString)
+      throws IllegalArgumentException {
+    if (!byteString.isValidUtf8()) {
+      throw new IllegalArgumentException("Byte string is not UTF-8.");
+    }
+  }
+
+  protected static <T> void addAll(final Iterable<T> values,
+      final Collection<? super T> list) {
+    Builder.addAll(values, list);
+  }
+  
+  /**
+   * A partial implementation of the {@link Message.Builder} interface which
+   * implements as many methods of that interface as possible in terms of
+   * other methods.
+   */
+  @SuppressWarnings("unchecked")
+  public abstract static class Builder<
+      MessageType extends AbstractMessageLite<MessageType, BuilderType>,
+      BuilderType extends Builder<MessageType, BuilderType>>
+      implements MessageLite.Builder {
+    // The compiler produces an error if this is not declared explicitly.
+    @Override
+    public abstract BuilderType clone();
+
+    @Override
+    public BuilderType mergeFrom(final CodedInputStream input) throws IOException {
+      return mergeFrom(input, ExtensionRegistryLite.getEmptyRegistry());
+    }
+
+    // Re-defined here for return type covariance.
+    @Override
+    public abstract BuilderType mergeFrom(
+        final CodedInputStream input, final ExtensionRegistryLite extensionRegistry)
+        throws IOException;
+
+    @Override
+    public BuilderType mergeFrom(final ByteString data) throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(
+          "Reading from a ByteString threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final ByteString data, final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input = data.newCodedInput();
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(
+          "Reading from a ByteString threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data) throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length);
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final int off, final int len)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input =
+            CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(
+          "Reading from a byte array threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    @Override
+    public BuilderType mergeFrom(final byte[] data, final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      return mergeFrom(data, 0, data.length, extensionRegistry);
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final byte[] data,
+        final int off,
+        final int len,
+        final ExtensionRegistryLite extensionRegistry)
+        throws InvalidProtocolBufferException {
+      try {
+        final CodedInputStream input =
+            CodedInputStream.newInstance(data, off, len);
+        mergeFrom(input, extensionRegistry);
+        input.checkLastTagWas(0);
+        return (BuilderType) this;
+      } catch (InvalidProtocolBufferException e) {
+        throw e;
+      } catch (IOException e) {
+        throw new RuntimeException(
+          "Reading from a byte array threw an IOException (should " +
+          "never happen).", e);
+      }
+    }
+
+    @Override
+    public BuilderType mergeFrom(final InputStream input) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput);
+      codedInput.checkLastTagWas(0);
+      return (BuilderType) this;
+    }
+
+    @Override
+    public BuilderType mergeFrom(
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final CodedInputStream codedInput = CodedInputStream.newInstance(input);
+      mergeFrom(codedInput, extensionRegistry);
+      codedInput.checkLastTagWas(0);
+      return (BuilderType) this;
+    }
+
+    /**
+     * An InputStream implementations which reads from some other InputStream
+     * but is limited to a particular number of bytes.  Used by
+     * mergeDelimitedFrom().  This is intentionally package-private so that
+     * UnknownFieldSet can share it.
+     */
+    static final class LimitedInputStream extends FilterInputStream {
+      private int limit;
+
+      LimitedInputStream(InputStream in, int limit) {
+        super(in);
+        this.limit = limit;
+      }
+
+      @Override
+      public int available() throws IOException {
+        return Math.min(super.available(), limit);
+      }
+
+      @Override
+      public int read() throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        final int result = super.read();
+        if (result >= 0) {
+          --limit;
+        }
+        return result;
+      }
+
+      @Override
+      public int read(final byte[] b, final int off, int len)
+                      throws IOException {
+        if (limit <= 0) {
+          return -1;
+        }
+        len = Math.min(len, limit);
+        final int result = super.read(b, off, len);
+        if (result >= 0) {
+          limit -= result;
+        }
+        return result;
+      }
+
+      @Override
+      public long skip(final long n) throws IOException {
+        final long result = super.skip(Math.min(n, limit));
+        if (result >= 0) {
+          limit -= result;
+        }
+        return result;
+      }
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(
+        final InputStream input, final ExtensionRegistryLite extensionRegistry) throws IOException {
+      final int firstByte = input.read();
+      if (firstByte == -1) {
+        return false;
+      }
+      final int size = CodedInputStream.readRawVarint32(firstByte, input);
+      final InputStream limitedInput = new LimitedInputStream(input, size);
+      mergeFrom(limitedInput, extensionRegistry);
+      return true;
+    }
+
+    @Override
+    public boolean mergeDelimitedFrom(final InputStream input) throws IOException {
+      return mergeDelimitedFrom(input,
+          ExtensionRegistryLite.getEmptyRegistry());
+    }
+    
+    @Override
+    @SuppressWarnings("unchecked") // isInstance takes care of this
+    public BuilderType mergeFrom(final MessageLite other) {
+      if (!getDefaultInstanceForType().getClass().isInstance(other)) {
+        throw new IllegalArgumentException(
+            "mergeFrom(MessageLite) can only merge messages of the same type.");
+      }
+        
+      return internalMergeFrom((MessageType) other);
+    }
+    
+    protected abstract BuilderType internalMergeFrom(MessageType message);
+
+    /**
+     * Construct an UninitializedMessageException reporting missing fields in
+     * the given message.
+     */
+    protected static UninitializedMessageException
+        newUninitializedMessageException(MessageLite message) {
+      return new UninitializedMessageException(message);
+    }
+
+    /**
+     * Adds the {@code values} to the {@code list}.  This is a helper method
+     * used by generated code.  Users should ignore it.
+     *
+     * @throws NullPointerException if {@code values} or any of the elements of
+     * {@code values} is null. When that happens, some elements of
+     * {@code values} may have already been added to the result {@code list}.
+     */
+    protected static <T> void addAll(final Iterable<T> values,
+                                     final Collection<? super T> list) {
+      if (values == null) {
+        throw new NullPointerException();
+      }
+      if (values instanceof LazyStringList) {
+        // For StringOrByteStringLists, check the underlying elements to avoid
+        // forcing conversions of ByteStrings to Strings.
+        checkForNullValues(((LazyStringList) values).getUnderlyingElements());
+        list.addAll((Collection<T>) values);
+      } else if (values instanceof Collection) {
+        checkForNullValues(values);
+        list.addAll((Collection<T>) values);
+      } else {
+        for (final T value : values) {
+          if (value == null) {
+            throw new NullPointerException();
+          }
+          list.add(value);
+        }
+      }
+    }
+
+    private static void checkForNullValues(final Iterable<?> values) {
+      for (final Object value : values) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+      }
+    }
+  }
+}
diff --git a/java/src/main/java/com/google/protobuf/AbstractParser.java b/java/src/main/java/com/google/protobuf/AbstractParser.java
new file mode 100644
index 00000000..66b0ee3b
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/AbstractParser.java
@@ -0,0 +1,258 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import com.google.protobuf.AbstractMessageLite.Builder.LimitedInputStream;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * A partial implementation of the {@link Parser} interface which implements
+ * as many methods of that interface as possible in terms of other methods.
+ *
+ * Note: This class implements all the convenience methods in the
+ * {@link Parser} interface. See {@link Parser} for related javadocs.
+ * Subclasses need to implement
+ * {@link Parser#parsePartialFrom(CodedInputStream, ExtensionRegistryLite)}
+ *
+ * @author liujisi@google.com (Pherl Liu)
+ */
+public abstract class AbstractParser<MessageType extends MessageLite>
+    implements Parser<MessageType> {
+  /**
+   * Creates an UninitializedMessageException for MessageType.
+   */
+  private UninitializedMessageException
+      newUninitializedMessageException(MessageType message) {
+    if (message instanceof AbstractMessageLite) {
+      return ((AbstractMessageLite) message).newUninitializedMessageException();
+    }
+    return new UninitializedMessageException(message);
+  }
+
+  /**
+   * Helper method to check if message is initialized.
+   *
+   * @throws InvalidProtocolBufferException if it is not initialized.
+   * @return The message to check.
+   */
+  private MessageType checkMessageInitialized(MessageType message)
+      throws InvalidProtocolBufferException {
+    if (message != null && !message.isInitialized()) {
+      throw newUninitializedMessageException(message)
+          .asInvalidProtocolBufferException()
+          .setUnfinishedMessage(message);
+    }
+    return message;
+  }
+
+  private static final ExtensionRegistryLite EMPTY_REGISTRY
+      = ExtensionRegistryLite.getEmptyRegistry();
+
+  @Override
+  public MessageType parsePartialFrom(CodedInputStream input)
+      throws InvalidProtocolBufferException {
+    return parsePartialFrom(input, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseFrom(CodedInputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(input, extensionRegistry));
+  }
+
+  @Override
+  public MessageType parseFrom(CodedInputStream input) throws InvalidProtocolBufferException {
+    return parseFrom(input, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parsePartialFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    MessageType message;
+    try {
+      CodedInputStream input = data.newCodedInput();
+      message = parsePartialFrom(input, extensionRegistry);
+      try {
+        input.checkLastTagWas(0);
+      } catch (InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(message);
+      }
+      return message;
+    } catch (InvalidProtocolBufferException e) {
+      throw e;
+    }
+  }
+
+  @Override
+  public MessageType parsePartialFrom(ByteString data) throws InvalidProtocolBufferException {
+    return parsePartialFrom(data, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseFrom(ByteString data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(parsePartialFrom(data, extensionRegistry));
+  }
+
+  @Override
+  public MessageType parseFrom(ByteString data) throws InvalidProtocolBufferException {
+    return parseFrom(data, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parsePartialFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    try {
+      CodedInputStream input = CodedInputStream.newInstance(data, off, len);
+      MessageType message = parsePartialFrom(input, extensionRegistry);
+      try {
+        input.checkLastTagWas(0);
+      } catch (InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(message);
+      }
+      return message;
+    } catch (InvalidProtocolBufferException e) {
+      throw e;
+    }
+  }
+
+  @Override
+  public MessageType parsePartialFrom(byte[] data, int off, int len)
+      throws InvalidProtocolBufferException {
+    return parsePartialFrom(data, off, len, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parsePartialFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return parsePartialFrom(data, 0, data.length, extensionRegistry);
+  }
+
+  @Override
+  public MessageType parsePartialFrom(byte[] data) throws InvalidProtocolBufferException {
+    return parsePartialFrom(data, 0, data.length, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseFrom(
+      byte[] data, int off, int len, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(data, off, len, extensionRegistry));
+  }
+
+  @Override
+  public MessageType parseFrom(byte[] data, int off, int len)
+      throws InvalidProtocolBufferException {
+    return parseFrom(data, off, len, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseFrom(byte[] data, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return parseFrom(data, 0, data.length, extensionRegistry);
+  }
+
+  @Override
+  public MessageType parseFrom(byte[] data) throws InvalidProtocolBufferException {
+    return parseFrom(data, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parsePartialFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    CodedInputStream codedInput = CodedInputStream.newInstance(input);
+    MessageType message = parsePartialFrom(codedInput, extensionRegistry);
+    try {
+      codedInput.checkLastTagWas(0);
+    } catch (InvalidProtocolBufferException e) {
+      throw e.setUnfinishedMessage(message);
+    }
+    return message;
+  }
+
+  @Override
+  public MessageType parsePartialFrom(InputStream input) throws InvalidProtocolBufferException {
+    return parsePartialFrom(input, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialFrom(input, extensionRegistry));
+  }
+
+  @Override
+  public MessageType parseFrom(InputStream input) throws InvalidProtocolBufferException {
+    return parseFrom(input, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parsePartialDelimitedFrom(
+      InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    int size;
+    try {
+      int firstByte = input.read();
+      if (firstByte == -1) {
+        return null;
+      }
+      size = CodedInputStream.readRawVarint32(firstByte, input);
+    } catch (IOException e) {
+      throw new InvalidProtocolBufferException(e.getMessage());
+    }
+    InputStream limitedInput = new LimitedInputStream(input, size);
+    return parsePartialFrom(limitedInput, extensionRegistry);
+  }
+
+  @Override
+  public MessageType parsePartialDelimitedFrom(InputStream input)
+      throws InvalidProtocolBufferException {
+    return parsePartialDelimitedFrom(input, EMPTY_REGISTRY);
+  }
+
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input, ExtensionRegistryLite extensionRegistry)
+      throws InvalidProtocolBufferException {
+    return checkMessageInitialized(
+        parsePartialDelimitedFrom(input, extensionRegistry));
+  }
+
+  @Override
+  public MessageType parseDelimitedFrom(InputStream input) throws InvalidProtocolBufferException {
+    return parseDelimitedFrom(input, EMPTY_REGISTRY);
+  }
+}
diff --git a/java/src/main/java/com/google/protobuf/AbstractProtobufList.java b/java/src/main/java/com/google/protobuf/AbstractProtobufList.java
new file mode 100644
index 00000000..b17db6e0
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/AbstractProtobufList.java
@@ -0,0 +1,180 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+import com.google.protobuf.Internal.ProtobufList;
+
+import java.util.AbstractList;
+import java.util.Collection;
+import java.util.List;
+import java.util.RandomAccess;
+
+/**
+ * An abstract implementation of {@link ProtobufList} which manages mutability semantics. All mutate
+ * methods must check if the list is mutable before proceeding. Subclasses must invoke
+ * {@link #ensureIsMutable()} manually when overriding those methods.
+ * <p>
+ * This implementation assumes all subclasses are array based, supporting random access.
+ */
+abstract class AbstractProtobufList<E> extends AbstractList<E> implements ProtobufList<E> {
+
+  protected static final int DEFAULT_CAPACITY = 10;
+
+  /**
+   * Whether or not this list is modifiable.
+   */
+  private boolean isMutable;
+
+  /**
+   * Constructs a mutable list by default.
+   */
+  AbstractProtobufList() {
+    isMutable = true;
+  }
+
+  @Override
+  public boolean equals(Object o) {
+    if (o == this) {
+      return true;
+    }
+    if (!(o instanceof List)) {
+      return false;
+    }
+    // Handle lists that do not support RandomAccess as efficiently as possible by using an iterator
+    // based approach in our super class. Otherwise our index based approach will avoid those
+    // allocations.
+    if (!(o instanceof RandomAccess)) {
+      return super.equals(o);
+    }
+
+    List<?> other = (List<?>) o;
+    final int size = size();
+    if (size != other.size()) {
+      return false;
+    }
+    for (int i = 0; i < size; i++) {
+      if (!get(i).equals(other.get(i))) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    final int size = size();
+    int hashCode = 1;
+    for (int i = 0; i < size; i++) {
+      hashCode = (31 * hashCode) + get(i).hashCode();
+    }
+    return hashCode;
+  }
+
+  @Override
+  public boolean add(E e) {
+    ensureIsMutable();
+    return super.add(e);
+  }
+
+  @Override
+  public void add(int index, E element) {
+    ensureIsMutable();
+    super.add(index, element);
+  }
+
+  @Override
+  public boolean addAll(Collection<? extends E> c) {
+    ensureIsMutable();
+    return super.addAll(c);
+  }
+  
+  @Override
+  public boolean addAll(int index, Collection<? extends E> c) {
+    ensureIsMutable();
+    return super.addAll(index, c);
+  }
+
+  @Override
+  public void clear() {
+    ensureIsMutable();
+    super.clear();
+  }
+  
+  @Override
+  public boolean isModifiable() {
+    return isMutable;
+  }
+  
+  @Override
+  public final void makeImmutable() {
+    isMutable = false;
+  }
+  
+  @Override
+  public E remove(int index) {
+    ensureIsMutable();
+    return super.remove(index);
+  }
+  
+  @Override
+  public boolean remove(Object o) {
+    ensureIsMutable();
+    return super.remove(o);
+  }
+  
+  @Override
+  public boolean removeAll(Collection<?> c) {
+    ensureIsMutable();
+    return super.removeAll(c);
+  }
+  
+  @Override
+  public boolean retainAll(Collection<?> c) {
+    ensureIsMutable();
+    return super.retainAll(c);
+  }
+  
+  @Override
+  public E set(int index, E element) {
+    ensureIsMutable();
+    return super.set(index, element);
+  }
+  
+  /**
+   * Throws an {@link UnsupportedOperationException} if the list is immutable. Subclasses are
+   * responsible for invoking this method on mutate operations.
+   */
+  protected void ensureIsMutable() {
+    if (!isMutable) {
+      throw new UnsupportedOperationException();
+    }
+  }
+}
diff --git a/java/src/main/java/com/google/protobuf/BlockingRpcChannel.java b/java/src/main/java/com/google/protobuf/BlockingRpcChannel.java
new file mode 100644
index 00000000..d535efb9
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/BlockingRpcChannel.java
@@ -0,0 +1,51 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+/**
+ * <p>Abstract interface for a blocking RPC channel.  {@code BlockingRpcChannel}
+ * is the blocking equivalent to {@link RpcChannel}.
+ *
+ * @author kenton@google.com Kenton Varda
+ * @author cpovirk@google.com Chris Povirk
+ */
+public interface BlockingRpcChannel {
+  /**
+   * Call the given method of the remote service and blocks until it returns.
+   * {@code callBlockingMethod()} is the blocking equivalent to
+   * {@link RpcChannel#callMethod}.
+   */
+  Message callBlockingMethod(
+      Descriptors.MethodDescriptor method,
+      RpcController controller,
+      Message request,
+      Message responsePrototype) throws ServiceException;
+}
diff --git a/java/src/main/java/com/google/protobuf/BlockingService.java b/java/src/main/java/com/google/protobuf/BlockingService.java
new file mode 100644
index 00000000..d01f0b8f
--- /dev/null
+++ b/java/src/main/java/com/google/protobuf/BlockingService.java
@@ -0,0 +1,64 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package com.google.protobuf;
+
+/**
+ * Blocking equivalent to {@link Service}.
+ *
+ * @author kenton@google.com Kenton Varda
+ * @author cpovirk@google.com Chris Povirk
+ */
+public interface BlockingService {
+  /**
+   * Equivalent to {@link Service#getDescriptorForType}.
+   */
+  Descriptors.ServiceDescriptor getDescriptorForType();
+
+  /**
+   * Equivalent to {@link Service#callMethod}, except that
+   * {@code callBlockingMethod()} returns the result of the RPC or throws a
+   * {@link ServiceException} if there is a failure, rather than passing the
+   * information to a callback.
+   */
+  Message callBlockingMethod(Descriptors.MethodDescriptor method,
+                             RpcController controller,
+                             Message request) throws ServiceException;
+
+  /**
+   * Equivalent to {@link Service#getRequestPrototype}.
+   */
+  Message getRequestPrototype(Descriptors.MethodDescriptor method);
+
+  /**
+   * Equivalent to {@link Service#getResponsePrototype}.
+   */
+  Message getResponsePrototype(Descriptors.MethodDescriptor method);
+}
diff --git a/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java b/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java
index d6a2f6fa..668d65ab 100644
--- a/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java
+++ b/java/util/src/main/java/com/google/protobuf/util/FieldMaskTree.java
@@ -264,7 +264,11 @@ class FieldMaskTree {
             }
           }
         } else {
-          destination.setField(field, source.getField(field));
+          if (source.hasField(field) || !options.replacePrimitiveFields()) {
+            destination.setField(field, source.getField(field));
+          } else {
+            destination.clearField(field);
+          }
         }
       }
     }
diff --git a/java/util/src/main/java/com/google/protobuf/util/FieldMaskUtil.java b/java/util/src/main/java/com/google/protobuf/util/FieldMaskUtil.java
index 0b3060a7..96961521 100644
--- a/java/util/src/main/java/com/google/protobuf/util/FieldMaskUtil.java
+++ b/java/util/src/main/java/com/google/protobuf/util/FieldMaskUtil.java
@@ -211,14 +211,19 @@ public class FieldMaskUtil {
   public static FieldMask normalize(FieldMask mask) {
     return new FieldMaskTree(mask).toFieldMask();
   }
-  
+
   /**
-   * Creates an union of two FieldMasks.
+   * Creates a union of two or more FieldMasks.
    */
-  public static FieldMask union(FieldMask mask1, FieldMask mask2) {
-    return new FieldMaskTree(mask1).mergeFromFieldMask(mask2).toFieldMask();
+  public static FieldMask union(
+      FieldMask firstMask, FieldMask secondMask, FieldMask... otherMasks) {
+    FieldMaskTree maskTree = new FieldMaskTree(firstMask).mergeFromFieldMask(secondMask);
+    for (FieldMask mask : otherMasks) {
+      maskTree.mergeFromFieldMask(mask);
+    }
+    return maskTree.toFieldMask();
   }
-  
+
   /**
    * Calculates the intersection of two FieldMasks.
    */
@@ -237,6 +242,9 @@ public class FieldMaskUtil {
   public static final class MergeOptions {
     private boolean replaceMessageFields = false;
     private boolean replaceRepeatedFields = false;
+    // TODO(b/28277137): change the default behavior to always replace primitive fields after
+    // fixing all failing TAP tests.
+    private boolean replacePrimitiveFields = false;
 
     /**
      * Whether to replace message fields (i.e., discard existing content in
@@ -257,7 +265,23 @@ public class FieldMaskUtil {
     public boolean replaceRepeatedFields() {
       return replaceRepeatedFields;
     }
-    
+
+    /**
+     * Whether to replace primitive (non-repeated and non-message) fields in
+     * destination message fields with the source primitive fields (i.e., if the
+     * field is set in the source, the value is copied to the
+     * destination; if the field is unset in the source, the field is cleared
+     * from the destination) when merging.
+     *
+     * <p>Default behavior is to always set the value of the source primitive
+     * field to the destination primitive field, and if the source field is
+     * unset, the default value of the source field is copied to the
+     * destination.
+     */
+    public boolean replacePrimitiveFields() {
+      return replacePrimitiveFields;
+    }
+
     public void setReplaceMessageFields(boolean value) {
       replaceMessageFields = value;
     }
@@ -265,10 +289,15 @@ public class FieldMaskUtil {
     public void setReplaceRepeatedFields(boolean value) {
       replaceRepeatedFields = value;
     }
+
+    public void setReplacePrimitiveFields(boolean value) {
+      replacePrimitiveFields = value;
+    }
   }
-  
+
   /**
-   * Merges fields specified by a FieldMask from one message to another.
+   * Merges fields specified by a FieldMask from one message to another with the
+   * specified merge options.
    */
   public static void merge(FieldMask mask, Message source,
       Message.Builder destination, MergeOptions options) {
diff --git a/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java b/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java
index 618e0072..3ee0fc6e 100644
--- a/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java
+++ b/java/util/src/test/java/com/google/protobuf/util/FieldMaskTreeTest.java
@@ -237,5 +237,25 @@ public class FieldMaskTreeTest extends TestCase {
     builder.getPayloadBuilder().setOptionalUint32(2000);
     new FieldMaskTree().addFieldPath("payload").merge(clearedSource, builder, options);
     assertEquals(false, builder.hasPayload());
+
+    // Test merging unset primitive fields.
+    builder = source.toBuilder();
+    builder.getPayloadBuilder().clearOptionalInt32();
+    NestedTestAllTypes sourceWithPayloadInt32Unset = builder.build();
+    builder = source.toBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.optional_int32")
+        .merge(sourceWithPayloadInt32Unset, builder, options);
+    assertEquals(true, builder.getPayload().hasOptionalInt32());
+    assertEquals(0, builder.getPayload().getOptionalInt32());
+
+    // Change to clear unset primitive fields.
+    options.setReplacePrimitiveFields(true);
+    builder = source.toBuilder();
+    new FieldMaskTree()
+        .addFieldPath("payload.optional_int32")
+        .merge(sourceWithPayloadInt32Unset, builder, options);
+    assertEquals(true, builder.hasPayload());
+    assertEquals(false, builder.getPayload().hasOptionalInt32());
   }
 }
diff --git a/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java b/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java
index a312fc33..194f7b9c 100644
--- a/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java
+++ b/java/util/src/test/java/com/google/protobuf/util/FieldMaskUtilTest.java
@@ -152,6 +152,15 @@ public class FieldMaskUtilTest extends TestCase {
     FieldMask result = FieldMaskUtil.union(mask1, mask2);
     assertEquals("bar,foo", FieldMaskUtil.toString(result));
   }
+
+  public void testUnion_usingVarArgs() throws Exception {
+    FieldMask mask1 = FieldMaskUtil.fromString("foo");
+    FieldMask mask2 = FieldMaskUtil.fromString("foo.bar,bar.quz");
+    FieldMask mask3 = FieldMaskUtil.fromString("bar.quz");
+    FieldMask mask4 = FieldMaskUtil.fromString("bar");
+    FieldMask result = FieldMaskUtil.union(mask1, mask2, mask3, mask4);
+    assertEquals("bar,foo", FieldMaskUtil.toString(result));
+  }
   
   public void testIntersection() throws Exception {
     // Only test a simple case here and expect
diff --git a/js/binary/utils.js b/js/binary/utils.js
index 875ff955..51405553 100644
--- a/js/binary/utils.js
+++ b/js/binary/utils.js
@@ -568,6 +568,56 @@ jspb.utils.hash64ArrayToDecimalStrings = function(hashes, signed) {
 
 
 /**
+ * Converts a signed or unsigned decimal string into its hash string
+ * representation.
+ * @param {string} dec
+ * @return {string}
+ */
+jspb.utils.decimalStringToHash64 = function(dec) {
+  goog.asserts.assert(dec.length > 0);
+
+  // Check for minus sign.
+  var minus = false;
+  if (dec[0] === '-') {
+    minus = true;
+    dec = dec.slice(1);
+  }
+
+  // Store result as a byte array.
+  var resultBytes = [0, 0, 0, 0, 0, 0, 0, 0];
+
+  // Set result to m*result + c.
+  function muladd(m, c) {
+    for (var i = 0; i < 8 && (m !== 1 || c > 0); i++) {
+      var r = m * resultBytes[i] + c;
+      resultBytes[i] = r & 0xFF;
+      c = r >>> 8;
+    }
+  }
+
+  // Negate the result bits.
+  function neg() {
+    for (var i = 0; i < 8; i++) {
+      resultBytes[i] = (~resultBytes[i]) & 0xFF;
+    }
+  }
+
+  // For each decimal digit, set result to 10*result + digit.
+  for (var i = 0; i < dec.length; i++) {
+    muladd(10, jspb.utils.DIGITS.indexOf(dec[i]));
+  }
+
+  // If there's a minus sign, convert into two's complement.
+  if (minus) {
+    neg();
+    muladd(1, 1);
+  }
+
+  return String.fromCharCode.apply(null, resultBytes);
+};
+
+
+/**
  * Converts an 8-character hash string into its hexadecimal representation.
  * @param {string} hash
  * @return {string}
diff --git a/js/binary/utils_test.js b/js/binary/utils_test.js
index 518d7597..d27e5ea2 100644
--- a/js/binary/utils_test.js
+++ b/js/binary/utils_test.js
@@ -197,6 +197,41 @@ describe('binaryUtilsTest', function() {
     assertEquals('123456789123456789', result[2]);
   });
 
+  /*
+   * Going from decimal strings to hash strings should be lossless.
+   */
+  it('testDecimalToHashConversion', function() {
+    var result;
+    var convert = jspb.utils.decimalStringToHash64;
+
+    result = convert('0');
+    assertEquals(String.fromCharCode.apply(null,
+      [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00]), result);
+
+    result = convert('-1');
+    assertEquals(String.fromCharCode.apply(null,
+      [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]), result);
+
+    result = convert('18446744073709551615');
+    assertEquals(String.fromCharCode.apply(null,
+      [0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF]), result);
+
+    result = convert('9223372036854775808');
+    assertEquals(String.fromCharCode.apply(null,
+      [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80]), result);
+
+    result = convert('-9223372036854775808');
+    assertEquals(String.fromCharCode.apply(null,
+      [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x80]), result);
+
+    result = convert('123456789123456789');
+    assertEquals(String.fromCharCode.apply(null,
+      [0x15, 0x5F, 0xD0, 0xAC, 0x4B, 0x9B, 0xB6, 0x01]), result);
+
+    result = convert('-123456789123456789');
+    assertEquals(String.fromCharCode.apply(null,
+      [0xEB, 0xA0, 0x2F, 0x53, 0xB4, 0x64, 0x49, 0xFE]), result);
+  });
 
   /**
    * Going from hash strings to hex strings should be lossless.
diff --git a/js/gulpfile.js b/js/gulpfile.js
index 7e44aa76..c5220153 100644
--- a/js/gulpfile.js
+++ b/js/gulpfile.js
@@ -1,7 +1,11 @@
 var gulp = require('gulp');
-var exec = require('child_process').exec;
+var execFile = require('child_process').execFile;
 var glob = require('glob');
 
+function exec(command, cb) {
+  execFile('sh', ['-c', command], cb);
+}
+
 var protoc = process.env.PROTOC || '../src/protoc';
 
 gulp.task('genproto_closure', function (cb) {
diff --git a/js/package.json b/js/package.json
index 6418e507..c16417ca 100644
--- a/js/package.json
+++ b/js/package.json
@@ -13,7 +13,7 @@
     "glob": "~6.0.4"
   },
   "scripts": {
-    "test": "./node_modules/gulp/bin/gulp.js test"
+    "test": "node ./node_modules/gulp/bin/gulp.js test"
   },
   "repository": {
     "type": "git",
diff --git a/objectivec/DevTools/full_mac_build.sh b/objectivec/DevTools/full_mac_build.sh
index 4d4930dc..ff51d9f0 100755
--- a/objectivec/DevTools/full_mac_build.sh
+++ b/objectivec/DevTools/full_mac_build.sh
@@ -26,8 +26,9 @@ OPTIONS:
          Issue a clean before the normal build.
    -a, --autogen
          Start by rerunning autogen & configure.
-   -r, --regenerate-cpp-descriptors
-         The descriptor.proto is checked in generated, cause it to regenerate.
+   -r, --regenerate-descriptors
+         Run generate_descriptor_proto.sh to regenerate all the checked in
+         proto sources.
    -j #, --jobs #
          Force the number of parallel jobs (useful for debugging build issues).
    --core-only
@@ -71,7 +72,7 @@ fi
 
 DO_AUTOGEN=no
 DO_CLEAN=no
-REGEN_CPP_DESCRIPTORS=no
+REGEN_DESCRIPTORS=no
 CORE_ONLY=no
 DO_XCODE_IOS_TESTS=yes
 DO_XCODE_OSX_TESTS=yes
@@ -88,8 +89,8 @@ while [[ $# != 0 ]]; do
     -a | --autogen )
       DO_AUTOGEN=yes
       ;;
-    -r | --regenerate-cpp-descriptors )
-      REGEN_CPP_DESCRIPTORS=yes
+    -r | --regenerate-descriptors )
+      REGEN_DESCRIPTORS=yes
       ;;
     -j | --jobs )
       shift
@@ -164,8 +165,8 @@ if [[ "${DO_CLEAN}" == "yes" ]] ; then
   fi
 fi
 
-if [[ "${REGEN_CPP_DESCRIPTORS}" == "yes" ]] ; then
-  header "Regenerating the C++ descriptor sources."
+if [[ "${REGEN_DESCRIPTORS}" == "yes" ]] ; then
+  header "Regenerating the descriptor sources."
   ./generate_descriptor_proto.sh -j "${NUM_MAKE_JOBS}"
 fi
 
@@ -184,29 +185,8 @@ else
   cd ..
 fi
 
-header "Ensuring the ObjC descriptors are current."
-# Find the newest input file (protos, compiler, and the generator script).
-# (these patterns catch some extra stuff, but better to over sample than under)
-readonly NewestInput=$(find \
-   src/google/protobuf/*.proto \
-   src/.libs src/*.la src/protoc \
-   objectivec/generate_well_known_types.sh \
-      -type f -print0 \
-      | xargs -0 stat -f "%m %N" \
-      | sort -n | tail -n1 | cut -f2- -d" ")
-# Find the oldest output file.
-readonly OldestOutput=$(find \
-      "${ProtoRootDir}/objectivec/google" \
-      -type f -print0 \
-      | xargs -0 stat -f "%m %N" \
-      | sort -n -r | tail -n1 | cut -f2- -d" ")
-# If the newest input is newer than the oldest output, regenerate.
-if [[ "${NewestInput}" -nt "${OldestOutput}" ]] ; then
-  echo ">> Newest input is newer than oldest output, regenerating."
-  objectivec/generate_well_known_types.sh -j "${NUM_MAKE_JOBS}"
-else
-  echo ">> Newest input is older than oldest output, no need to regenerating."
-fi
+# Ensure the WKT sources checked in are current.
+objectivec/generate_well_known_types.sh --check-only -j "${NUM_MAKE_JOBS}"
 
 header "Checking on the ObjC Runtime Code"
 objectivec/DevTools/pddm_tests.py
diff --git a/objectivec/GPBCodedOutputStream.h b/objectivec/GPBCodedOutputStream.h
index e67efd2d..8272880d 100644
--- a/objectivec/GPBCodedOutputStream.h
+++ b/objectivec/GPBCodedOutputStream.h
@@ -112,7 +112,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a double for the given field number.
 - (void)writeDouble:(int32_t)fieldNumber value:(double)value;
-/// Write a packaged array of double for the given field number.
+/// Write a packed array of double for the given field number.
 - (void)writeDoubleArray:(int32_t)fieldNumber
                   values:(GPBDoubleArray *)values
                      tag:(uint32_t)tag;
@@ -121,7 +121,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a float for the given field number.
 - (void)writeFloat:(int32_t)fieldNumber value:(float)value;
-/// Write a packaged array of float for the given field number.
+/// Write a packed array of float for the given field number.
 - (void)writeFloatArray:(int32_t)fieldNumber
                  values:(GPBFloatArray *)values
                     tag:(uint32_t)tag;
@@ -130,7 +130,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a uint64_t for the given field number.
 - (void)writeUInt64:(int32_t)fieldNumber value:(uint64_t)value;
-/// Write a packaged array of uint64_t for the given field number.
+/// Write a packed array of uint64_t for the given field number.
 - (void)writeUInt64Array:(int32_t)fieldNumber
                   values:(GPBUInt64Array *)values
                      tag:(uint32_t)tag;
@@ -139,7 +139,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int64_t for the given field number.
 - (void)writeInt64:(int32_t)fieldNumber value:(int64_t)value;
-/// Write a packaged array of int64_t for the given field number.
+/// Write a packed array of int64_t for the given field number.
 - (void)writeInt64Array:(int32_t)fieldNumber
                  values:(GPBInt64Array *)values
                     tag:(uint32_t)tag;
@@ -148,7 +148,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int32_t for the given field number.
 - (void)writeInt32:(int32_t)fieldNumber value:(int32_t)value;
-/// Write a packaged array of int32_t for the given field number.
+/// Write a packed array of int32_t for the given field number.
 - (void)writeInt32Array:(int32_t)fieldNumber
                  values:(GPBInt32Array *)values
                     tag:(uint32_t)tag;
@@ -157,7 +157,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a uint32_t for the given field number.
 - (void)writeUInt32:(int32_t)fieldNumber value:(uint32_t)value;
-/// Write a packaged array of uint32_t for the given field number.
+/// Write a packed array of uint32_t for the given field number.
 - (void)writeUInt32Array:(int32_t)fieldNumber
                   values:(GPBUInt32Array *)values
                      tag:(uint32_t)tag;
@@ -166,7 +166,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a uint64_t for the given field number.
 - (void)writeFixed64:(int32_t)fieldNumber value:(uint64_t)value;
-/// Write a packaged array of uint64_t for the given field number.
+/// Write a packed array of uint64_t for the given field number.
 - (void)writeFixed64Array:(int32_t)fieldNumber
                    values:(GPBUInt64Array *)values
                       tag:(uint32_t)tag;
@@ -175,7 +175,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a uint32_t for the given field number.
 - (void)writeFixed32:(int32_t)fieldNumber value:(uint32_t)value;
-/// Write a packaged array of uint32_t for the given field number.
+/// Write a packed array of uint32_t for the given field number.
 - (void)writeFixed32Array:(int32_t)fieldNumber
                    values:(GPBUInt32Array *)values
                       tag:(uint32_t)tag;
@@ -184,7 +184,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int32_t for the given field number.
 - (void)writeSInt32:(int32_t)fieldNumber value:(int32_t)value;
-/// Write a packaged array of int32_t for the given field number.
+/// Write a packed array of int32_t for the given field number.
 - (void)writeSInt32Array:(int32_t)fieldNumber
                   values:(GPBInt32Array *)values
                      tag:(uint32_t)tag;
@@ -193,7 +193,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int64_t for the given field number.
 - (void)writeSInt64:(int32_t)fieldNumber value:(int64_t)value;
-/// Write a packaged array of int64_t for the given field number.
+/// Write a packed array of int64_t for the given field number.
 - (void)writeSInt64Array:(int32_t)fieldNumber
                   values:(GPBInt64Array *)values
                      tag:(uint32_t)tag;
@@ -202,7 +202,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int64_t for the given field number.
 - (void)writeSFixed64:(int32_t)fieldNumber value:(int64_t)value;
-/// Write a packaged array of int64_t for the given field number.
+/// Write a packed array of int64_t for the given field number.
 - (void)writeSFixed64Array:(int32_t)fieldNumber
                     values:(GPBInt64Array *)values
                        tag:(uint32_t)tag;
@@ -211,7 +211,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int32_t for the given field number.
 - (void)writeSFixed32:(int32_t)fieldNumber value:(int32_t)value;
-/// Write a packaged array of int32_t for the given field number.
+/// Write a packed array of int32_t for the given field number.
 - (void)writeSFixed32Array:(int32_t)fieldNumber
                     values:(GPBInt32Array *)values
                        tag:(uint32_t)tag;
@@ -220,7 +220,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a BOOL for the given field number.
 - (void)writeBool:(int32_t)fieldNumber value:(BOOL)value;
-/// Write a packaged array of BOOL for the given field number.
+/// Write a packed array of BOOL for the given field number.
 - (void)writeBoolArray:(int32_t)fieldNumber
                 values:(GPBBoolArray *)values
                    tag:(uint32_t)tag;
@@ -229,7 +229,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 /// Write a int32_t for the given field number.
 - (void)writeEnum:(int32_t)fieldNumber value:(int32_t)value;
-/// Write a packaged array of int32_t for the given field number.
+/// Write a packed array of int32_t for the given field number.
 - (void)writeEnumArray:(int32_t)fieldNumber
                 values:(GPBEnumArray *)values
                    tag:(uint32_t)tag;
@@ -293,7 +293,7 @@ NS_ASSUME_NONNULL_END
 //%PDDM-DEFINE _WRITE_PACKABLE_DECLS(NAME, ARRAY_TYPE, TYPE)
 //%/// Write a TYPE for the given field number.
 //%- (void)write##NAME:(int32_t)fieldNumber value:(TYPE)value;
-//%/// Write a packaged array of TYPE for the given field number.
+//%/// Write a packed array of TYPE for the given field number.
 //%- (void)write##NAME##Array:(int32_t)fieldNumber
 //%       NAME$S     values:(GPB##ARRAY_TYPE##Array *)values
 //%       NAME$S        tag:(uint32_t)tag;
diff --git a/objectivec/GPBMessage.m b/objectivec/GPBMessage.m
index 0e1599dc..8134e259 100644
--- a/objectivec/GPBMessage.m
+++ b/objectivec/GPBMessage.m
@@ -2603,9 +2603,13 @@ static void MergeRepeatedNotPackedFieldFromCodedInputStream(
       size_t fieldOffset = field->description_->offset;
       switch (fieldDataType) {
         case GPBDataTypeBool: {
-          BOOL *selfValPtr = (BOOL *)&selfStorage[fieldOffset];
-          BOOL *otherValPtr = (BOOL *)&otherStorage[fieldOffset];
-          if (*selfValPtr != *otherValPtr) {
+          // Bools are stored in has_bits to avoid needing explicit space in
+          // the storage structure.
+          // (the field number passed to the HasIvar helper doesn't really
+          // matter since the offset is never negative)
+          BOOL selfValue = GPBGetHasIvar(self, (int32_t)(fieldOffset), 0);
+          BOOL otherValue = GPBGetHasIvar(other, (int32_t)(fieldOffset), 0);
+          if (selfValue != otherValue) {
             return NO;
           }
           break;
@@ -2714,8 +2718,12 @@ static void MergeRepeatedNotPackedFieldFromCodedInputStream(
       size_t fieldOffset = field->description_->offset;
       switch (fieldDataType) {
         case GPBDataTypeBool: {
-          BOOL *valPtr = (BOOL *)&storage[fieldOffset];
-          result = prime * result + *valPtr;
+          // Bools are stored in has_bits to avoid needing explicit space in
+          // the storage structure.
+          // (the field number passed to the HasIvar helper doesn't really
+          // matter since the offset is never negative)
+          BOOL value = GPBGetHasIvar(self, (int32_t)(fieldOffset), 0);
+          result = prime * result + value;
           break;
         }
         case GPBDataTypeSFixed32:
diff --git a/objectivec/Tests/GPBMessageTests.m b/objectivec/Tests/GPBMessageTests.m
index 43546156..89d1fce2 100644
--- a/objectivec/Tests/GPBMessageTests.m
+++ b/objectivec/Tests/GPBMessageTests.m
@@ -1947,4 +1947,76 @@
                  EnumTestMsg_MyEnum_NegTwo);
 }
 
+- (void)testOneBasedEnumHolder {
+  // Test case for https://github.com/google/protobuf/issues/1453
+  // Message with no explicit defaults, but a non zero default for an enum.
+  MessageWithOneBasedEnum *enumMsg = [MessageWithOneBasedEnum message];
+  XCTAssertEqual(enumMsg.enumField, MessageWithOneBasedEnum_OneBasedEnum_One);
+}
+
+- (void)testBoolOffsetUsage {
+  // Bools use storage within has_bits; this test ensures that this is honored
+  // in all places where things should crash or fail based on reading out of
+  // field storage instead.
+  BoolOnlyMessage *msg1 = [BoolOnlyMessage message];
+  BoolOnlyMessage *msg2 = [BoolOnlyMessage message];
+
+  msg1.boolField1 = YES;
+  msg2.boolField1 = YES;
+  msg1.boolField3 = YES;
+  msg2.boolField3 = YES;
+  msg1.boolField5 = YES;
+  msg2.boolField5 = YES;
+  msg1.boolField7 = YES;
+  msg2.boolField7 = YES;
+  msg1.boolField9 = YES;
+  msg2.boolField9 = YES;
+  msg1.boolField11 = YES;
+  msg2.boolField11 = YES;
+  msg1.boolField13 = YES;
+  msg2.boolField13 = YES;
+  msg1.boolField15 = YES;
+  msg2.boolField15 = YES;
+  msg1.boolField17 = YES;
+  msg2.boolField17 = YES;
+  msg1.boolField19 = YES;
+  msg2.boolField19 = YES;
+  msg1.boolField21 = YES;
+  msg2.boolField21 = YES;
+  msg1.boolField23 = YES;
+  msg2.boolField23 = YES;
+  msg1.boolField25 = YES;
+  msg2.boolField25 = YES;
+  msg1.boolField27 = YES;
+  msg2.boolField27 = YES;
+  msg1.boolField29 = YES;
+  msg2.boolField29 = YES;
+  msg1.boolField31 = YES;
+  msg2.boolField31 = YES;
+
+  msg1.boolField32 = YES;
+  msg2.boolField32 = YES;
+
+  XCTAssertTrue(msg1 != msg2); // Different pointers.
+  XCTAssertEqual([msg1 hash], [msg2 hash]);
+  XCTAssertEqualObjects(msg1, msg2);
+
+  BoolOnlyMessage *msg1Prime = [[msg1 copy] autorelease];
+  XCTAssertTrue(msg1Prime != msg1); // Different pointers.
+  XCTAssertEqual([msg1 hash], [msg1Prime hash]);
+  XCTAssertEqualObjects(msg1, msg1Prime);
+
+  // Field set in one, but not the other means they don't match (even if
+  // set to default value).
+  msg1Prime.boolField2 = NO;
+  XCTAssertNotEqualObjects(msg1Prime, msg1);
+  // And when set to different values.
+  msg1.boolField2 = YES;
+  XCTAssertNotEqualObjects(msg1Prime, msg1);
+  // And then they match again.
+  msg1.boolField2 = NO;
+  XCTAssertEqualObjects(msg1Prime, msg1);
+  XCTAssertEqual([msg1 hash], [msg1Prime hash]);
+}
+
 @end
diff --git a/objectivec/Tests/unittest_objc.proto b/objectivec/Tests/unittest_objc.proto
index 9483cb1d..f6ab6a24 100644
--- a/objectivec/Tests/unittest_objc.proto
+++ b/objectivec/Tests/unittest_objc.proto
@@ -401,3 +401,49 @@ message EnumTestMsg {
 
   repeated MyEnum mumble = 4;
 }
+
+// Test case for https://github.com/google/protobuf/issues/1453
+// Message with no explicit defaults, but a non zero default for an enum.
+message MessageWithOneBasedEnum {
+  enum OneBasedEnum {
+    ONE = 1;
+    TWO = 2;
+  }
+  optional OneBasedEnum enum_field = 1;
+}
+
+// Message with all bools for testing things related to bool storage.
+message BoolOnlyMessage {
+  optional bool bool_field_1 = 1;
+  optional bool bool_field_2 = 2;
+  optional bool bool_field_3 = 3;
+  optional bool bool_field_4 = 4;
+  optional bool bool_field_5 = 5;
+  optional bool bool_field_6 = 6;
+  optional bool bool_field_7 = 7;
+  optional bool bool_field_8 = 8;
+  optional bool bool_field_9 = 9;
+  optional bool bool_field_10 = 10;
+  optional bool bool_field_11 = 11;
+  optional bool bool_field_12 = 12;
+  optional bool bool_field_13 = 13;
+  optional bool bool_field_14 = 14;
+  optional bool bool_field_15 = 15;
+  optional bool bool_field_16 = 16;
+  optional bool bool_field_17 = 17;
+  optional bool bool_field_18 = 18;
+  optional bool bool_field_19 = 19;
+  optional bool bool_field_20 = 20;
+  optional bool bool_field_21 = 21;
+  optional bool bool_field_22 = 22;
+  optional bool bool_field_23 = 23;
+  optional bool bool_field_24 = 24;
+  optional bool bool_field_25 = 25;
+  optional bool bool_field_26 = 26;
+  optional bool bool_field_27 = 27;
+  optional bool bool_field_28 = 28;
+  optional bool bool_field_29 = 29;
+  optional bool bool_field_30 = 30;
+  optional bool bool_field_31 = 31;
+  optional bool bool_field_32 = 32;
+}
diff --git a/objectivec/generate_well_known_types.sh b/objectivec/generate_well_known_types.sh
index be9b38a5..36c34603 100755
--- a/objectivec/generate_well_known_types.sh
+++ b/objectivec/generate_well_known_types.sh
@@ -12,6 +12,13 @@ set -eu
 readonly ScriptDir=$(dirname "$(echo $0 | sed -e "s,^\([^/]\),$(pwd)/\1,")")
 readonly ProtoRootDir="${ScriptDir}/.."
 
+# Flag for continuous integration to check that everything is current.
+CHECK_ONLY=0
+if [[ $# -ge 1 && ( "$1" == "--check-only" ) ]] ; then
+  CHECK_ONLY=1
+  shift
+fi
+
 pushd "${ProtoRootDir}" > /dev/null
 
 if test ! -e src/google/protobuf/stubs/common.h; then
@@ -46,4 +53,24 @@ declare -a RUNTIME_PROTO_FILES=( \
   google/protobuf/type.proto \
   google/protobuf/wrappers.proto)
 
-./protoc --objc_out="${ProtoRootDir}/objectivec" ${RUNTIME_PROTO_FILES[@]}
+# Generate to a temp directory to see if they match.
+TMP_DIR=$(mktemp -d)
+trap "rm -rf ${TMP_DIR}" EXIT
+./protoc --objc_out="${TMP_DIR}" ${RUNTIME_PROTO_FILES[@]}
+set +e
+diff -r "${TMP_DIR}/google" "${ProtoRootDir}/objectivec/google" > /dev/null
+if [[ $? -eq 0 ]] ; then
+  echo "Generated source for WellKnownTypes is current."
+  exit 0
+fi
+set -e
+
+# If check only mode, error out.
+if [[ "${CHECK_ONLY}" == 1 ]] ; then
+  echo "ERROR: The WKTs need to be regenerated! Run $0"
+  exit 1
+fi
+
+# Copy them over.
+echo "Copying over updated WellKnownType sources."
+cp -r "${TMP_DIR}/google/." "${ProtoRootDir}/objectivec/google/"
diff --git a/objectivec/google/protobuf/Any.pbobjc.h b/objectivec/google/protobuf/Any.pbobjc.h
index 79ec0fb7..4002a989 100644
--- a/objectivec/google/protobuf/Any.pbobjc.h
+++ b/objectivec/google/protobuf/Any.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -33,8 +36,36 @@ typedef GPB_ENUM(GPBAny_FieldNumber) {
   GPBAny_FieldNumber_Value = 2,
 };
 
-/// `Any` contains an arbitrary serialized message along with a URL
-/// that describes the type of the serialized message.
+/// `Any` contains an arbitrary serialized protocol buffer message along with a
+/// URL that describes the type of the serialized message.
+///
+/// Protobuf library provides support to pack/unpack Any values in the form
+/// of utility functions or additional generated methods of the Any type.
+///
+/// Example 1: Pack and unpack a message in C++.
+///
+///     Foo foo = ...;
+///     Any any;
+///     any.PackFrom(foo);
+///     ...
+///     if (any.UnpackTo(&foo)) {
+///       ...
+///     }
+///
+/// Example 2: Pack and unpack a message in Java.
+///
+///     Foo foo = ...;
+///     Any any = Any.pack(foo);
+///     ...
+///     if (any.is(Foo.class)) {
+///       foo = any.unpack(Foo.class);
+///     }
+///
+/// The pack methods provided by protobuf library will by default use
+/// 'type.googleapis.com/full.type.name' as the type URL and the unpack
+/// methods only use the fully qualified type name after the last '/'
+/// in the type URL, for example "foo.bar.com/x/y.z" will yield type
+/// name "y.z".
 ///
 ///
 /// JSON
@@ -67,7 +98,7 @@ typedef GPB_ENUM(GPBAny_FieldNumber) {
 @interface GPBAny : GPBMessage
 
 /// A URL/resource name whose content describes the type of the
-/// serialized message.
+/// serialized protocol buffer message.
 ///
 /// For URLs which use the schema `http`, `https`, or no schema, the
 /// following restrictions and interpretations apply:
@@ -75,6 +106,8 @@ typedef GPB_ENUM(GPBAny_FieldNumber) {
 /// * If no schema is provided, `https` is assumed.
 /// * The last segment of the URL's path must represent the fully
 ///   qualified name of the type (as in `path/google.protobuf.Duration`).
+///   The name should be in a canonical form (e.g., leading "." is
+///   not accepted).
 /// * An HTTP GET on the URL must yield a [google.protobuf.Type][]
 ///   value in binary format, or produce an error.
 /// * Applications are allowed to cache lookup results based on the
@@ -87,7 +120,7 @@ typedef GPB_ENUM(GPBAny_FieldNumber) {
 /// used with implementation specific semantics.
 @property(nonatomic, readwrite, copy, null_resettable) NSString *typeURL;
 
-/// Must be valid serialized data of the above specified type.
+/// Must be a valid serialized protocol buffer of the above specified type.
 @property(nonatomic, readwrite, copy, null_resettable) NSData *value;
 
 @end
@@ -96,4 +129,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Any.pbobjc.m b/objectivec/google/protobuf/Any.pbobjc.m
index 7cbf0def..6a1bf894 100644
--- a/objectivec/google/protobuf/Any.pbobjc.m
+++ b/objectivec/google/protobuf/Any.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Any.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBAnyRoot
 
 @implementation GPBAnyRoot
@@ -85,4 +88,6 @@ typedef struct GPBAny__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Api.pbobjc.h b/objectivec/google/protobuf/Api.pbobjc.h
index 3f7e99c6..d66df629 100644
--- a/objectivec/google/protobuf/Api.pbobjc.h
+++ b/objectivec/google/protobuf/Api.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 @class GPBMethod;
@@ -254,4 +257,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Api.pbobjc.m b/objectivec/google/protobuf/Api.pbobjc.m
index 2b2f62ea..45a06e60 100644
--- a/objectivec/google/protobuf/Api.pbobjc.m
+++ b/objectivec/google/protobuf/Api.pbobjc.m
@@ -7,6 +7,9 @@
 #import "google/protobuf/Type.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBApiRoot
 
 @implementation GPBApiRoot
@@ -340,4 +343,6 @@ typedef struct GPBMixin__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Duration.pbobjc.h b/objectivec/google/protobuf/Duration.pbobjc.h
index 3685a614..29888d6c 100644
--- a/objectivec/google/protobuf/Duration.pbobjc.h
+++ b/objectivec/google/protobuf/Duration.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -93,4 +96,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Duration.pbobjc.m b/objectivec/google/protobuf/Duration.pbobjc.m
index bb79c7a3..7dd6b64a 100644
--- a/objectivec/google/protobuf/Duration.pbobjc.m
+++ b/objectivec/google/protobuf/Duration.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Duration.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBDurationRoot
 
 @implementation GPBDurationRoot
@@ -80,4 +83,6 @@ typedef struct GPBDuration__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Empty.pbobjc.h b/objectivec/google/protobuf/Empty.pbobjc.h
index 6651ef71..f33db017 100644
--- a/objectivec/google/protobuf/Empty.pbobjc.h
+++ b/objectivec/google/protobuf/Empty.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -45,4 +48,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Empty.pbobjc.m b/objectivec/google/protobuf/Empty.pbobjc.m
index 5d7f8f19..88753aaf 100644
--- a/objectivec/google/protobuf/Empty.pbobjc.m
+++ b/objectivec/google/protobuf/Empty.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Empty.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBEmptyRoot
 
 @implementation GPBEmptyRoot
@@ -56,4 +59,6 @@ typedef struct GPBEmpty__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/FieldMask.pbobjc.h b/objectivec/google/protobuf/FieldMask.pbobjc.h
index 931f664c..73cbd8a5 100644
--- a/objectivec/google/protobuf/FieldMask.pbobjc.h
+++ b/objectivec/google/protobuf/FieldMask.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -81,7 +84,7 @@ typedef GPB_ENUM(GPBFieldMask_FieldNumber) {
 /// operation applies to all fields (as if a FieldMask of all fields
 /// had been specified).
 ///
-/// Note that a field mask does not necessarily applies to the
+/// Note that a field mask does not necessarily apply to the
 /// top-level response message. In case of a REST get operation, the
 /// field mask applies directly to the response, but in case of a REST
 /// list operation, the mask instead applies to each individual message
@@ -154,6 +157,33 @@ typedef GPB_ENUM(GPBFieldMask_FieldNumber) {
 ///     {
 ///       mask: "user.displayName,photo"
 ///     }
+///
+/// # Field Masks and Oneof Fields
+///
+/// Field masks treat fields in oneofs just as regular fields. Consider the
+/// following message:
+///
+///     message SampleMessage {
+///       oneof test_oneof {
+///         string name = 4;
+///         SubMessage sub_message = 9;
+///       }
+///     }
+///
+/// The field mask can be:
+///
+///     mask {
+///       paths: "name"
+///     }
+///
+/// Or:
+///
+///     mask {
+///       paths: "sub_message"
+///     }
+///
+/// Note that oneof type names ("test_oneof" in this case) cannot be used in
+/// paths.
 @interface GPBFieldMask : GPBMessage
 
 /// The set of field mask paths.
@@ -167,4 +197,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/FieldMask.pbobjc.m b/objectivec/google/protobuf/FieldMask.pbobjc.m
index 36fc758e..8c241afc 100644
--- a/objectivec/google/protobuf/FieldMask.pbobjc.m
+++ b/objectivec/google/protobuf/FieldMask.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/FieldMask.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBFieldMaskRoot
 
 @implementation GPBFieldMaskRoot
@@ -69,4 +72,6 @@ typedef struct GPBFieldMask__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/SourceContext.pbobjc.h b/objectivec/google/protobuf/SourceContext.pbobjc.h
index 67b6d479..8775348e 100644
--- a/objectivec/google/protobuf/SourceContext.pbobjc.h
+++ b/objectivec/google/protobuf/SourceContext.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -46,4 +49,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/SourceContext.pbobjc.m b/objectivec/google/protobuf/SourceContext.pbobjc.m
index 4e8bf3d2..95007126 100644
--- a/objectivec/google/protobuf/SourceContext.pbobjc.m
+++ b/objectivec/google/protobuf/SourceContext.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/SourceContext.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBSourceContextRoot
 
 @implementation GPBSourceContextRoot
@@ -69,4 +72,6 @@ typedef struct GPBSourceContext__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Struct.pbobjc.h b/objectivec/google/protobuf/Struct.pbobjc.h
index e2388e22..3924b4b7 100644
--- a/objectivec/google/protobuf/Struct.pbobjc.h
+++ b/objectivec/google/protobuf/Struct.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 @class GPBListValue;
@@ -67,7 +70,7 @@ typedef GPB_ENUM(GPBStruct_FieldNumber) {
 /// The JSON representation for `Struct` is JSON object.
 @interface GPBStruct : GPBMessage
 
-/// Map of dynamically typed values.
+/// Unordered map of dynamically typed values.
 @property(nonatomic, readwrite, strong, null_resettable) NSMutableDictionary<NSString*, GPBValue*> *fields;
 /// The number of items in @c fields without causing the array to be created.
 @property(nonatomic, readonly) NSUInteger fields_Count;
@@ -159,4 +162,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Struct.pbobjc.m b/objectivec/google/protobuf/Struct.pbobjc.m
index 0601a4b2..60940027 100644
--- a/objectivec/google/protobuf/Struct.pbobjc.m
+++ b/objectivec/google/protobuf/Struct.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Struct.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBStructRoot
 
 @implementation GPBStructRoot
@@ -265,4 +268,6 @@ typedef struct GPBListValue__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Timestamp.pbobjc.h b/objectivec/google/protobuf/Timestamp.pbobjc.h
index b66b323a..925dca84 100644
--- a/objectivec/google/protobuf/Timestamp.pbobjc.h
+++ b/objectivec/google/protobuf/Timestamp.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -105,4 +108,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Timestamp.pbobjc.m b/objectivec/google/protobuf/Timestamp.pbobjc.m
index 14161159..f35e435d 100644
--- a/objectivec/google/protobuf/Timestamp.pbobjc.m
+++ b/objectivec/google/protobuf/Timestamp.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Timestamp.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBTimestampRoot
 
 @implementation GPBTimestampRoot
@@ -80,4 +83,6 @@ typedef struct GPBTimestamp__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Type.pbobjc.h b/objectivec/google/protobuf/Type.pbobjc.h
index efaeab39..590d970b 100644
--- a/objectivec/google/protobuf/Type.pbobjc.h
+++ b/objectivec/google/protobuf/Type.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 @class GPBAny;
@@ -365,4 +368,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Type.pbobjc.m b/objectivec/google/protobuf/Type.pbobjc.m
index 175c0233..5554a222 100644
--- a/objectivec/google/protobuf/Type.pbobjc.m
+++ b/objectivec/google/protobuf/Type.pbobjc.m
@@ -7,6 +7,9 @@
 #import "google/protobuf/SourceContext.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBTypeRoot
 
 @implementation GPBTypeRoot
@@ -685,4 +688,6 @@ typedef struct GPBOption__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Wrappers.pbobjc.h b/objectivec/google/protobuf/Wrappers.pbobjc.h
index 0ca439a8..46510500 100644
--- a/objectivec/google/protobuf/Wrappers.pbobjc.h
+++ b/objectivec/google/protobuf/Wrappers.pbobjc.h
@@ -9,6 +9,9 @@
 
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 CF_EXTERN_C_BEGIN
 
 NS_ASSUME_NONNULL_BEGIN
@@ -174,4 +177,6 @@ NS_ASSUME_NONNULL_END
 
 CF_EXTERN_C_END
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/objectivec/google/protobuf/Wrappers.pbobjc.m b/objectivec/google/protobuf/Wrappers.pbobjc.m
index b1b5be69..5cc6c2e4 100644
--- a/objectivec/google/protobuf/Wrappers.pbobjc.m
+++ b/objectivec/google/protobuf/Wrappers.pbobjc.m
@@ -5,6 +5,9 @@
 #import "google/protobuf/Wrappers.pbobjc.h"
 // @@protoc_insertion_point(imports)
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+
 #pragma mark - GPBWrappersRoot
 
 @implementation GPBWrappersRoot
@@ -412,4 +415,6 @@ typedef struct GPBBytesValue__storage_ {
 @end
 
 
+#pragma clang diagnostic pop
+
 // @@protoc_insertion_point(global_scope)
diff --git a/php/tests/autoload.php b/php/tests/autoload.php
new file mode 100644
index 00000000..af88ba01
--- /dev/null
+++ b/php/tests/autoload.php
@@ -0,0 +1,4 @@
+<?php
+
+require_once('test.pb.php');
+require_once('test_util.php');
diff --git a/python/google/protobuf/descriptor.py b/python/google/protobuf/descriptor.py
index 5f613c88..3209b34d 100755
--- a/python/google/protobuf/descriptor.py
+++ b/python/google/protobuf/descriptor.py
@@ -783,6 +783,8 @@ class FileDescriptor(DescriptorBase):
   serialized_pb: (str) Byte string of serialized
     descriptor_pb2.FileDescriptorProto.
   dependencies: List of other FileDescriptors this FileDescriptor depends on.
+  public_dependencies: A list of FileDescriptors, subset of the dependencies
+    above, which were declared as "public".
   message_types_by_name: Dict of message names of their descriptors.
   enum_types_by_name: Dict of enum names and their descriptors.
   extensions_by_name: Dict of extension names and their descriptors.
@@ -794,7 +796,8 @@ class FileDescriptor(DescriptorBase):
     _C_DESCRIPTOR_CLASS = _message.FileDescriptor
 
     def __new__(cls, name, package, options=None, serialized_pb=None,
-                dependencies=None, syntax=None, pool=None):
+                dependencies=None, public_dependencies=None,
+                syntax=None, pool=None):
       # FileDescriptor() is called from various places, not only from generated
       # files, to register dynamic proto files and messages.
       if serialized_pb:
@@ -805,7 +808,8 @@ class FileDescriptor(DescriptorBase):
         return super(FileDescriptor, cls).__new__(cls)
 
   def __init__(self, name, package, options=None, serialized_pb=None,
-               dependencies=None, syntax=None, pool=None):
+               dependencies=None, public_dependencies=None,
+               syntax=None, pool=None):
     """Constructor."""
     super(FileDescriptor, self).__init__(options, 'FileOptions')
 
@@ -822,6 +826,7 @@ class FileDescriptor(DescriptorBase):
     self.enum_types_by_name = {}
     self.extensions_by_name = {}
     self.dependencies = (dependencies or [])
+    self.public_dependencies = (public_dependencies or [])
 
     if (api_implementation.Type() == 'cpp' and
         self.serialized_pb is not None):
diff --git a/python/google/protobuf/descriptor_pool.py b/python/google/protobuf/descriptor_pool.py
index 3e80795c..20a33701 100644
--- a/python/google/protobuf/descriptor_pool.py
+++ b/python/google/protobuf/descriptor_pool.py
@@ -319,6 +319,7 @@ class DescriptorPool(object):
     if file_proto.name not in self._file_descriptors:
       built_deps = list(self._GetDeps(file_proto.dependency))
       direct_deps = [self.FindFileByName(n) for n in file_proto.dependency]
+      public_deps = [direct_deps[i] for i in file_proto.public_dependency]
 
       file_descriptor = descriptor.FileDescriptor(
           pool=self,
@@ -327,7 +328,8 @@ class DescriptorPool(object):
           syntax=file_proto.syntax,
           options=file_proto.options,
           serialized_pb=file_proto.SerializeToString(),
-          dependencies=direct_deps)
+          dependencies=direct_deps,
+          public_dependencies=public_deps)
       if _USE_C_DESCRIPTORS:
         # When using C++ descriptors, all objects defined in the file were added
         # to the C++ database when the FileDescriptor was built above.
diff --git a/python/google/protobuf/internal/api_implementation.py b/python/google/protobuf/internal/api_implementation.py
index ffcf7511..460a4a6c 100755
--- a/python/google/protobuf/internal/api_implementation.py
+++ b/python/google/protobuf/internal/api_implementation.py
@@ -32,6 +32,7 @@
 """
 
 import os
+import warnings
 import sys
 
 try:
@@ -78,6 +79,11 @@ _implementation_type = os.getenv('PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION',
 if _implementation_type != 'python':
   _implementation_type = 'cpp'
 
+if 'PyPy' in sys.version and _implementation_type == 'cpp':
+  warnings.warn('PyPy does not work yet with cpp protocol buffers. '
+                'Falling back to the python implementation.')
+  _implementation_type = 'python'
+
 # This environment variable can be used to switch between the two
 # 'cpp' implementations, overriding the compile-time constants in the
 # _api_implementation module. Right now only '2' is supported. Any other
diff --git a/python/google/protobuf/internal/descriptor_pool_test.py b/python/google/protobuf/internal/descriptor_pool_test.py
index 4b1811d8..6a13e0bc 100644
--- a/python/google/protobuf/internal/descriptor_pool_test.py
+++ b/python/google/protobuf/internal/descriptor_pool_test.py
@@ -51,6 +51,7 @@ from google.protobuf.internal import descriptor_pool_test1_pb2
 from google.protobuf.internal import descriptor_pool_test2_pb2
 from google.protobuf.internal import factory_test1_pb2
 from google.protobuf.internal import factory_test2_pb2
+from google.protobuf.internal import more_messages_pb2
 from google.protobuf import descriptor
 from google.protobuf import descriptor_database
 from google.protobuf import descriptor_pool
@@ -60,11 +61,8 @@ from google.protobuf import symbol_database
 
 class DescriptorPoolTest(unittest.TestCase):
 
-  def CreatePool(self):
-    return descriptor_pool.DescriptorPool()
-
   def setUp(self):
-    self.pool = self.CreatePool()
+    self.pool = descriptor_pool.DescriptorPool()
     self.factory_test1_fd = descriptor_pb2.FileDescriptorProto.FromString(
         factory_test1_pb2.DESCRIPTOR.serialized_pb)
     self.factory_test2_fd = descriptor_pb2.FileDescriptorProto.FromString(
@@ -275,10 +273,13 @@ class DescriptorPoolTest(unittest.TestCase):
     self.testFindMessageTypeByName()
 
   def testComplexNesting(self):
+    more_messages_desc = descriptor_pb2.FileDescriptorProto.FromString(
+        more_messages_pb2.DESCRIPTOR.serialized_pb)
     test1_desc = descriptor_pb2.FileDescriptorProto.FromString(
         descriptor_pool_test1_pb2.DESCRIPTOR.serialized_pb)
     test2_desc = descriptor_pb2.FileDescriptorProto.FromString(
         descriptor_pool_test2_pb2.DESCRIPTOR.serialized_pb)
+    self.pool.Add(more_messages_desc)
     self.pool.Add(test1_desc)
     self.pool.Add(test2_desc)
     TEST1_FILE.CheckFile(self, self.pool)
@@ -350,25 +351,15 @@ class DescriptorPoolTest(unittest.TestCase):
     _CheckDefaultValues(message_class())
 
 
-@unittest.skipIf(api_implementation.Type() != 'cpp',
-                 'explicit tests of the C++ implementation')
-class CppDescriptorPoolTest(DescriptorPoolTest):
-  # TODO(amauryfa): remove when descriptor_pool.DescriptorPool() creates true
-  # C++ descriptor pool object for C++ implementation.
-
-  def CreatePool(self):
-    # pylint: disable=g-import-not-at-top
-    from google.protobuf.pyext import _message
-    return _message.DescriptorPool()
-
-
 class ProtoFile(object):
 
-  def __init__(self, name, package, messages, dependencies=None):
+  def __init__(self, name, package, messages, dependencies=None,
+               public_dependencies=None):
     self.name = name
     self.package = package
     self.messages = messages
     self.dependencies = dependencies or []
+    self.public_dependencies = public_dependencies or []
 
   def CheckFile(self, test, pool):
     file_desc = pool.FindFileByName(self.name)
@@ -376,6 +367,8 @@ class ProtoFile(object):
     test.assertEqual(self.package, file_desc.package)
     dependencies_names = [f.name for f in file_desc.dependencies]
     test.assertEqual(self.dependencies, dependencies_names)
+    public_dependencies_names = [f.name for f in file_desc.public_dependencies]
+    test.assertEqual(self.public_dependencies, public_dependencies_names)
     for name, msg_type in self.messages.items():
       msg_type.CheckType(test, None, name, file_desc)
 
@@ -613,18 +606,9 @@ class AddDescriptorTest(unittest.TestCase):
       pool.FindFileContainingSymbol(
           'protobuf_unittest.TestAllTypes')
 
-  def _GetDescriptorPoolClass(self):
-    # Test with both implementations of descriptor pools.
-    if api_implementation.Type() == 'cpp':
-      # pylint: disable=g-import-not-at-top
-      from google.protobuf.pyext import _message
-      return _message.DescriptorPool
-    else:
-      return descriptor_pool.DescriptorPool
-
   def testEmptyDescriptorPool(self):
-    # Check that an empty DescriptorPool() contains no message.
-    pool = self._GetDescriptorPoolClass()()
+    # Check that an empty DescriptorPool() contains no messages.
+    pool = descriptor_pool.DescriptorPool()
     proto_file_name = descriptor_pb2.DESCRIPTOR.name
     self.assertRaises(KeyError, pool.FindFileByName, proto_file_name)
     # Add the above file to the pool
@@ -636,7 +620,7 @@ class AddDescriptorTest(unittest.TestCase):
 
   def testCustomDescriptorPool(self):
     # Create a new pool, and add a file descriptor.
-    pool = self._GetDescriptorPoolClass()()
+    pool = descriptor_pool.DescriptorPool()
     file_desc = descriptor_pb2.FileDescriptorProto(
         name='some/file.proto', package='package')
     file_desc.message_type.add(name='Message')
@@ -757,7 +741,9 @@ TEST2_FILE = ProtoFile(
              ExtensionField(1001, 'DescriptorPoolTest1')),
         ]),
     },
-    dependencies=['google/protobuf/internal/descriptor_pool_test1.proto'])
+    dependencies=['google/protobuf/internal/descriptor_pool_test1.proto',
+                  'google/protobuf/internal/more_messages.proto'],
+    public_dependencies=['google/protobuf/internal/more_messages.proto'])
 
 
 if __name__ == '__main__':
diff --git a/python/google/protobuf/internal/descriptor_pool_test2.proto b/python/google/protobuf/internal/descriptor_pool_test2.proto
index e3fa660c..a218eccb 100644
--- a/python/google/protobuf/internal/descriptor_pool_test2.proto
+++ b/python/google/protobuf/internal/descriptor_pool_test2.proto
@@ -33,6 +33,7 @@ syntax = "proto2";
 package google.protobuf.python.internal;
 
 import "google/protobuf/internal/descriptor_pool_test1.proto";
+import public "google/protobuf/internal/more_messages.proto";
 
 
 message DescriptorPoolTest3 {
diff --git a/python/google/protobuf/internal/message_factory_test.py b/python/google/protobuf/internal/message_factory_test.py
index 54b1f688..7bb7d1ac 100644
--- a/python/google/protobuf/internal/message_factory_test.py
+++ b/python/google/protobuf/internal/message_factory_test.py
@@ -131,6 +131,60 @@ class MessageFactoryTest(unittest.TestCase):
       self.assertEqual('test1', msg1.Extensions[ext1])
       self.assertEqual('test2', msg1.Extensions[ext2])
 
+  def testDuplicateExtensionNumber(self):
+    pool = descriptor_pool.DescriptorPool()
+    factory = message_factory.MessageFactory(pool=pool)
+
+    # Add Container message.
+    f = descriptor_pb2.FileDescriptorProto()
+    f.name = 'google/protobuf/internal/container.proto'
+    f.package = 'google.protobuf.python.internal'
+    msg = f.message_type.add()
+    msg.name = 'Container'
+    rng = msg.extension_range.add()
+    rng.start = 1
+    rng.end = 10
+    pool.Add(f)
+    msgs = factory.GetMessages([f.name])
+    self.assertIn('google.protobuf.python.internal.Container', msgs)
+
+    # Extend container.
+    f = descriptor_pb2.FileDescriptorProto()
+    f.name = 'google/protobuf/internal/extension.proto'
+    f.package = 'google.protobuf.python.internal'
+    f.dependency.append('google/protobuf/internal/container.proto')
+    msg = f.message_type.add()
+    msg.name = 'Extension'
+    ext = msg.extension.add()
+    ext.name = 'extension_field'
+    ext.number = 2
+    ext.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL
+    ext.type_name = 'Extension'
+    ext.extendee = 'Container'
+    pool.Add(f)
+    msgs = factory.GetMessages([f.name])
+    self.assertIn('google.protobuf.python.internal.Extension', msgs)
+
+    # Add Duplicate extending the same field number.
+    f = descriptor_pb2.FileDescriptorProto()
+    f.name = 'google/protobuf/internal/duplicate.proto'
+    f.package = 'google.protobuf.python.internal'
+    f.dependency.append('google/protobuf/internal/container.proto')
+    msg = f.message_type.add()
+    msg.name = 'Duplicate'
+    ext = msg.extension.add()
+    ext.name = 'extension_field'
+    ext.number = 2
+    ext.label = descriptor_pb2.FieldDescriptorProto.LABEL_OPTIONAL
+    ext.type_name = 'Duplicate'
+    ext.extendee = 'Container'
+    pool.Add(f)
+
+    with self.assertRaises(Exception) as cm:
+      factory.GetMessages([f.name])
+
+    self.assertIsInstance(cm.exception, (AssertionError, ValueError))
+
 
 if __name__ == '__main__':
   unittest.main()
diff --git a/python/google/protobuf/internal/message_test.py b/python/google/protobuf/internal/message_test.py
index 1232ccc9..4ee31d8e 100755
--- a/python/google/protobuf/internal/message_test.py
+++ b/python/google/protobuf/internal/message_test.py
@@ -57,18 +57,18 @@ try:
 except ImportError:
   import unittest
 
-from google.protobuf.internal import _parameterized
+from google.protobuf import map_unittest_pb2
+from google.protobuf import unittest_pb2
+from google.protobuf import unittest_proto3_arena_pb2
 from google.protobuf import descriptor_pb2
 from google.protobuf import descriptor_pool
-from google.protobuf import map_unittest_pb2
 from google.protobuf import message_factory
 from google.protobuf import text_format
-from google.protobuf import unittest_pb2
-from google.protobuf import unittest_proto3_arena_pb2
 from google.protobuf.internal import api_implementation
 from google.protobuf.internal import packed_field_test_pb2
 from google.protobuf.internal import test_util
 from google.protobuf import message
+from google.protobuf.internal import _parameterized
 
 if six.PY3:
   long = int
@@ -1265,7 +1265,10 @@ class Proto3Test(unittest.TestCase):
     self.assertFalse(-2**33 in msg.map_int64_int64)
     self.assertFalse(123 in msg.map_uint32_uint32)
     self.assertFalse(2**33 in msg.map_uint64_uint64)
+    self.assertFalse(123 in msg.map_int32_double)
+    self.assertFalse(False in msg.map_bool_bool)
     self.assertFalse('abc' in msg.map_string_string)
+    self.assertFalse(111 in msg.map_int32_bytes)
     self.assertFalse(888 in msg.map_int32_enum)
 
     # Accessing an unset key returns the default.
@@ -1273,7 +1276,12 @@ class Proto3Test(unittest.TestCase):
     self.assertEqual(0, msg.map_int64_int64[-2**33])
     self.assertEqual(0, msg.map_uint32_uint32[123])
     self.assertEqual(0, msg.map_uint64_uint64[2**33])
+    self.assertEqual(0.0, msg.map_int32_double[123])
+    self.assertTrue(isinstance(msg.map_int32_double[123], float))
+    self.assertEqual(False, msg.map_bool_bool[False])
+    self.assertTrue(isinstance(msg.map_bool_bool[False], bool))
     self.assertEqual('', msg.map_string_string['abc'])
+    self.assertEqual(b'', msg.map_int32_bytes[111])
     self.assertEqual(0, msg.map_int32_enum[888])
 
     # It also sets the value in the map
@@ -1281,7 +1289,10 @@ class Proto3Test(unittest.TestCase):
     self.assertTrue(-2**33 in msg.map_int64_int64)
     self.assertTrue(123 in msg.map_uint32_uint32)
     self.assertTrue(2**33 in msg.map_uint64_uint64)
+    self.assertTrue(123 in msg.map_int32_double)
+    self.assertTrue(False in msg.map_bool_bool)
     self.assertTrue('abc' in msg.map_string_string)
+    self.assertTrue(111 in msg.map_int32_bytes)
     self.assertTrue(888 in msg.map_int32_enum)
 
     self.assertIsInstance(msg.map_string_string['abc'], six.text_type)
@@ -1587,6 +1598,21 @@ class Proto3Test(unittest.TestCase):
     matching_dict = {2: 4, 3: 6, 4: 8}
     self.assertMapIterEquals(msg.map_int32_int32.items(), matching_dict)
 
+  def testMapItems(self):
+    # Map items used to have strange behaviors when use c extension. Because
+    # [] may reorder the map and invalidate any exsting iterators.
+    # TODO(jieluo): Check if [] reordering the map is a bug or intended
+    # behavior.
+    msg = map_unittest_pb2.TestMap()
+    msg.map_string_string['local_init_op'] = ''
+    msg.map_string_string['trainable_variables'] = ''
+    msg.map_string_string['variables'] = ''
+    msg.map_string_string['init_op'] = ''
+    msg.map_string_string['summaries'] = ''
+    items1 = msg.map_string_string.items()
+    items2 = msg.map_string_string.items()
+    self.assertEqual(items1, items2)
+
   def testMapIterationClearMessage(self):
     # Iterator needs to work even if message and map are deleted.
     msg = map_unittest_pb2.TestMap()
diff --git a/python/google/protobuf/internal/proto_builder_test.py b/python/google/protobuf/internal/proto_builder_test.py
index 822ad895..36dfbfde 100644
--- a/python/google/protobuf/internal/proto_builder_test.py
+++ b/python/google/protobuf/internal/proto_builder_test.py
@@ -40,6 +40,7 @@ try:
   import unittest2 as unittest
 except ImportError:
   import unittest
+
 from google.protobuf import descriptor_pb2
 from google.protobuf import descriptor_pool
 from google.protobuf import proto_builder
diff --git a/python/google/protobuf/internal/python_message.py b/python/google/protobuf/internal/python_message.py
index 87f60666..f8f73dd2 100755
--- a/python/google/protobuf/internal/python_message.py
+++ b/python/google/protobuf/internal/python_message.py
@@ -56,7 +56,14 @@ import struct
 import weakref
 
 import six
-import six.moves.copyreg as copyreg
+try:
+  import six.moves.copyreg as copyreg
+except ImportError:
+  # On some platforms, for example gMac, we run native Python because there is
+  # nothing like hermetic Python. This means lesser control on the system and
+  # the six.moves package may be missing (is missing on 20150321 on gMac). Be
+  # extra conservative and try to load the old replacement if it fails.
+  import copy_reg as copyreg
 
 # We use "as" to avoid name collisions with variables.
 from google.protobuf.internal import containers
@@ -490,6 +497,9 @@ def _AddInitMethod(message_descriptor, cls):
       if field is None:
         raise TypeError("%s() got an unexpected keyword argument '%s'" %
                         (message_descriptor.name, field_name))
+      if field_value is None:
+        # field=None is the same as no field at all.
+        continue
       if field.label == _FieldDescriptor.LABEL_REPEATED:
         copy = field._default_constructor(self)
         if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE:  # Composite
@@ -889,17 +899,6 @@ def _AddClearExtensionMethod(cls):
   cls.ClearExtension = ClearExtension
 
 
-def _AddClearMethod(message_descriptor, cls):
-  """Helper for _AddMessageMethods()."""
-  def Clear(self):
-    # Clear fields.
-    self._fields = {}
-    self._unknown_fields = ()
-    self._oneofs = {}
-    self._Modified()
-  cls.Clear = Clear
-
-
 def _AddHasExtensionMethod(cls):
   """Helper for _AddMessageMethods()."""
   def HasExtension(self, extension_handle):
@@ -999,16 +998,6 @@ def _AddUnicodeMethod(unused_message_descriptor, cls):
   cls.__unicode__ = __unicode__
 
 
-def _AddSetListenerMethod(cls):
-  """Helper for _AddMessageMethods()."""
-  def SetListener(self, listener):
-    if listener is None:
-      self._listener = message_listener_mod.NullMessageListener()
-    else:
-      self._listener = listener
-  cls._SetListener = SetListener
-
-
 def _BytesForNonRepeatedElement(value, field_number, field_type):
   """Returns the number of bytes needed to serialize a non-repeated element.
   The returned byte count includes space for tag information and any
@@ -1288,6 +1277,32 @@ def _AddWhichOneofMethod(message_descriptor, cls):
   cls.WhichOneof = WhichOneof
 
 
+def _Clear(self):
+  # Clear fields.
+  self._fields = {}
+  self._unknown_fields = ()
+  self._oneofs = {}
+  self._Modified()
+
+
+def _DiscardUnknownFields(self):
+  self._unknown_fields = []
+  for field, value in self.ListFields():
+    if field.cpp_type == _FieldDescriptor.CPPTYPE_MESSAGE:
+      if field.label == _FieldDescriptor.LABEL_REPEATED:
+        for sub_message in value:
+          sub_message.DiscardUnknownFields()
+      else:
+        value.DiscardUnknownFields()
+
+
+def _SetListener(self, listener):
+  if listener is None:
+    self._listener = message_listener_mod.NullMessageListener()
+  else:
+    self._listener = listener
+
+
 def _AddMessageMethods(message_descriptor, cls):
   """Adds implementations of all Message methods to cls."""
   _AddListFieldsMethod(message_descriptor, cls)
@@ -1296,12 +1311,10 @@ def _AddMessageMethods(message_descriptor, cls):
   if message_descriptor.is_extendable:
     _AddClearExtensionMethod(cls)
     _AddHasExtensionMethod(cls)
-  _AddClearMethod(message_descriptor, cls)
   _AddEqualsMethod(message_descriptor, cls)
   _AddStrMethod(message_descriptor, cls)
   _AddReprMethod(message_descriptor, cls)
   _AddUnicodeMethod(message_descriptor, cls)
-  _AddSetListenerMethod(cls)
   _AddByteSizeMethod(message_descriptor, cls)
   _AddSerializeToStringMethod(message_descriptor, cls)
   _AddSerializePartialToStringMethod(message_descriptor, cls)
@@ -1309,6 +1322,10 @@ def _AddMessageMethods(message_descriptor, cls):
   _AddIsInitializedMethod(message_descriptor, cls)
   _AddMergeFromMethod(cls)
   _AddWhichOneofMethod(message_descriptor, cls)
+  # Adds methods which do not depend on cls.
+  cls.Clear = _Clear
+  cls.DiscardUnknownFields = _DiscardUnknownFields
+  cls._SetListener = _SetListener
 
 
 def _AddPrivateHelperMethods(message_descriptor, cls):
@@ -1518,3 +1535,14 @@ class _ExtensionDict(object):
       Extension field descriptor.
     """
     return self._extended_message._extensions_by_name.get(name, None)
+
+  def _FindExtensionByNumber(self, number):
+    """Tries to find a known extension with the field number.
+
+    Args:
+      number: Extension field number.
+
+    Returns:
+      Extension field descriptor.
+    """
+    return self._extended_message._extensions_by_number.get(number, None)
diff --git a/python/google/protobuf/internal/reflection_test.py b/python/google/protobuf/internal/reflection_test.py
index 9e61ea0e..6dc2fffe 100755
--- a/python/google/protobuf/internal/reflection_test.py
+++ b/python/google/protobuf/internal/reflection_test.py
@@ -120,11 +120,13 @@ class ReflectionTest(unittest.TestCase):
     proto = unittest_pb2.TestAllTypes(
         optional_int32=24,
         optional_double=54.321,
-        optional_string='optional_string')
+        optional_string='optional_string',
+        optional_float=None)
 
     self.assertEqual(24, proto.optional_int32)
     self.assertEqual(54.321, proto.optional_double)
     self.assertEqual('optional_string', proto.optional_string)
+    self.assertFalse(proto.HasField("optional_float"))
 
   def testRepeatedScalarConstructor(self):
     # Constructor with only repeated scalar types should succeed.
@@ -132,12 +134,14 @@ class ReflectionTest(unittest.TestCase):
         repeated_int32=[1, 2, 3, 4],
         repeated_double=[1.23, 54.321],
         repeated_bool=[True, False, False],
-        repeated_string=["optional_string"])
+        repeated_string=["optional_string"],
+        repeated_float=None)
 
     self.assertEqual([1, 2, 3, 4], list(proto.repeated_int32))
     self.assertEqual([1.23, 54.321], list(proto.repeated_double))
     self.assertEqual([True, False, False], list(proto.repeated_bool))
     self.assertEqual(["optional_string"], list(proto.repeated_string))
+    self.assertEqual([], list(proto.repeated_float))
 
   def testRepeatedCompositeConstructor(self):
     # Constructor with only repeated composite types should succeed.
@@ -188,7 +192,8 @@ class ReflectionTest(unittest.TestCase):
         repeated_foreign_message=[
             unittest_pb2.ForeignMessage(c=-43),
             unittest_pb2.ForeignMessage(c=45324),
-            unittest_pb2.ForeignMessage(c=12)])
+            unittest_pb2.ForeignMessage(c=12)],
+        optional_nested_message=None)
 
     self.assertEqual(24, proto.optional_int32)
     self.assertEqual('optional_string', proto.optional_string)
@@ -205,6 +210,7 @@ class ReflectionTest(unittest.TestCase):
          unittest_pb2.ForeignMessage(c=45324),
          unittest_pb2.ForeignMessage(c=12)],
         list(proto.repeated_foreign_message))
+    self.assertFalse(proto.HasField("optional_nested_message"))
 
   def testConstructorTypeError(self):
     self.assertRaises(
diff --git a/python/google/protobuf/internal/text_format_test.py b/python/google/protobuf/internal/text_format_test.py
index 8ce0a44f..ab2bf05b 100755
--- a/python/google/protobuf/internal/text_format_test.py
+++ b/python/google/protobuf/internal/text_format_test.py
@@ -250,6 +250,36 @@ class TextFormatTest(TextFormatBase):
     message.c = 123
     self.assertEqual('c: 123\n', str(message))
 
+  def testPrintField(self, message_module):
+    message = message_module.TestAllTypes()
+    field = message.DESCRIPTOR.fields_by_name['optional_float']
+    value = message.optional_float
+    out = text_format.TextWriter(False)
+    text_format.PrintField(field, value, out)
+    self.assertEqual('optional_float: 0.0\n', out.getvalue())
+    out.close()
+    # Test Printer
+    out = text_format.TextWriter(False)
+    printer = text_format._Printer(out)
+    printer.PrintField(field, value)
+    self.assertEqual('optional_float: 0.0\n', out.getvalue())
+    out.close()
+
+  def testPrintFieldValue(self, message_module):
+    message = message_module.TestAllTypes()
+    field = message.DESCRIPTOR.fields_by_name['optional_float']
+    value = message.optional_float
+    out = text_format.TextWriter(False)
+    text_format.PrintFieldValue(field, value, out)
+    self.assertEqual('0.0', out.getvalue())
+    out.close()
+    # Test Printer
+    out = text_format.TextWriter(False)
+    printer = text_format._Printer(out)
+    printer.PrintFieldValue(field, value)
+    self.assertEqual('0.0', out.getvalue())
+    out.close()
+
   def testParseAllFields(self, message_module):
     message = message_module.TestAllTypes()
     test_util.SetAllFields(message)
@@ -616,6 +646,26 @@ class Proto2Tests(TextFormatBase):
         '  text: \"bar\"\n'
         '}\n')
 
+  def testPrintMessageSetByFieldNumber(self):
+    out = text_format.TextWriter(False)
+    message = unittest_mset_pb2.TestMessageSetContainer()
+    ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
+    ext2 = unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
+    message.message_set.Extensions[ext1].i = 23
+    message.message_set.Extensions[ext2].str = 'foo'
+    text_format.PrintMessage(message, out, use_field_number=True)
+    self.CompareToGoldenText(
+        out.getvalue(),
+        '1 {\n'
+        '  1545008 {\n'
+        '    15: 23\n'
+        '  }\n'
+        '  1547769 {\n'
+        '    25: \"foo\"\n'
+        '  }\n'
+        '}\n')
+    out.close()
+
   def testPrintMessageSetAsOneLine(self):
     message = unittest_mset_pb2.TestMessageSetContainer()
     ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
@@ -656,6 +706,48 @@ class Proto2Tests(TextFormatBase):
     self.assertEqual(23, message.message_set.Extensions[ext1].i)
     self.assertEqual('foo', message.message_set.Extensions[ext2].str)
 
+  def testParseMessageByFieldNumber(self):
+    message = unittest_pb2.TestAllTypes()
+    text = ('34: 1\n'
+            'repeated_uint64: 2\n')
+    text_format.Parse(text, message, allow_field_number=True)
+    self.assertEqual(1, message.repeated_uint64[0])
+    self.assertEqual(2, message.repeated_uint64[1])
+
+    message = unittest_mset_pb2.TestMessageSetContainer()
+    text = ('1 {\n'
+            '  1545008 {\n'
+            '    15: 23\n'
+            '  }\n'
+            '  1547769 {\n'
+            '    25: \"foo\"\n'
+            '  }\n'
+            '}\n')
+    text_format.Parse(text, message, allow_field_number=True)
+    ext1 = unittest_mset_pb2.TestMessageSetExtension1.message_set_extension
+    ext2 = unittest_mset_pb2.TestMessageSetExtension2.message_set_extension
+    self.assertEqual(23, message.message_set.Extensions[ext1].i)
+    self.assertEqual('foo', message.message_set.Extensions[ext2].str)
+
+    # Can't parse field number without set allow_field_number=True.
+    message = unittest_pb2.TestAllTypes()
+    text = '34:1\n'
+    six.assertRaisesRegex(
+        self,
+        text_format.ParseError,
+        (r'1:1 : Message type "\w+.TestAllTypes" has no field named '
+         r'"34".'),
+        text_format.Parse, text, message)
+
+    # Can't parse if field number is not found.
+    text = '1234:1\n'
+    six.assertRaisesRegex(
+        self,
+        text_format.ParseError,
+        (r'1:1 : Message type "\w+.TestAllTypes" has no field named '
+         r'"1234".'),
+        text_format.Parse, text, message, allow_field_number=True)
+
   def testPrintAllExtensions(self):
     message = unittest_pb2.TestAllExtensions()
     test_util.SetAllExtensions(message)
@@ -696,6 +788,7 @@ class Proto2Tests(TextFormatBase):
     text = ('message_set {\n'
             '  [unknown_extension] {\n'
             '    i: 23\n'
+            '    bin: "\xe0"'
             '    [nested_unknown_ext]: {\n'
             '      i: 23\n'
             '      test: "test_string"\n'
diff --git a/python/google/protobuf/internal/type_checkers.py b/python/google/protobuf/internal/type_checkers.py
index f30ca6a8..1be3ad9a 100755
--- a/python/google/protobuf/internal/type_checkers.py
+++ b/python/google/protobuf/internal/type_checkers.py
@@ -109,6 +109,16 @@ class TypeChecker(object):
     return proposed_value
 
 
+class TypeCheckerWithDefault(TypeChecker):
+
+  def __init__(self, default_value, *acceptable_types):
+    TypeChecker.__init__(self, acceptable_types)
+    self._default_value = default_value
+
+  def DefaultValue(self):
+    return self._default_value
+
+
 # IntValueChecker and its subclasses perform integer type-checks
 # and bounds-checks.
 class IntValueChecker(object):
@@ -212,12 +222,13 @@ _VALUE_CHECKERS = {
     _FieldDescriptor.CPPTYPE_INT64: Int64ValueChecker(),
     _FieldDescriptor.CPPTYPE_UINT32: Uint32ValueChecker(),
     _FieldDescriptor.CPPTYPE_UINT64: Uint64ValueChecker(),
-    _FieldDescriptor.CPPTYPE_DOUBLE: TypeChecker(
-        float, int, long),
-    _FieldDescriptor.CPPTYPE_FLOAT: TypeChecker(
-        float, int, long),
-    _FieldDescriptor.CPPTYPE_BOOL: TypeChecker(bool, int),
-    _FieldDescriptor.CPPTYPE_STRING: TypeChecker(bytes),
+    _FieldDescriptor.CPPTYPE_DOUBLE: TypeCheckerWithDefault(
+        0.0, float, int, long),
+    _FieldDescriptor.CPPTYPE_FLOAT: TypeCheckerWithDefault(
+        0.0, float, int, long),
+    _FieldDescriptor.CPPTYPE_BOOL: TypeCheckerWithDefault(
+        False, bool, int),
+    _FieldDescriptor.CPPTYPE_STRING: TypeCheckerWithDefault(b'', bytes),
     }
 
 
diff --git a/python/google/protobuf/internal/unknown_fields_test.py b/python/google/protobuf/internal/unknown_fields_test.py
index bb2748e4..84073f1c 100755
--- a/python/google/protobuf/internal/unknown_fields_test.py
+++ b/python/google/protobuf/internal/unknown_fields_test.py
@@ -119,6 +119,26 @@ class UnknownFieldsTest(unittest.TestCase):
     message.ParseFromString(self.all_fields.SerializeToString())
     self.assertNotEqual(self.empty_message, message)
 
+  def testDiscardUnknownFields(self):
+    self.empty_message.DiscardUnknownFields()
+    self.assertEqual(b'', self.empty_message.SerializeToString())
+    # Test message field and repeated message field.
+    message = unittest_pb2.TestAllTypes()
+    other_message = unittest_pb2.TestAllTypes()
+    other_message.optional_string = 'discard'
+    message.optional_nested_message.ParseFromString(
+        other_message.SerializeToString())
+    message.repeated_nested_message.add().ParseFromString(
+        other_message.SerializeToString())
+    self.assertNotEqual(
+        b'', message.optional_nested_message.SerializeToString())
+    self.assertNotEqual(
+        b'', message.repeated_nested_message[0].SerializeToString())
+    message.DiscardUnknownFields()
+    self.assertEqual(b'', message.optional_nested_message.SerializeToString())
+    self.assertEqual(
+        b'', message.repeated_nested_message[0].SerializeToString())
+
 
 class UnknownFieldsAccessorsTest(unittest.TestCase):
 
diff --git a/python/google/protobuf/internal/well_known_types.py b/python/google/protobuf/internal/well_known_types.py
index d35fcc5f..7c5dffd0 100644
--- a/python/google/protobuf/internal/well_known_types.py
+++ b/python/google/protobuf/internal/well_known_types.py
@@ -82,10 +82,14 @@ class Any(object):
     msg.ParseFromString(self.value)
     return True
 
+  def TypeName(self):
+    """Returns the protobuf type name of the inner message."""
+    # Only last part is to be used: b/25630112
+    return self.type_url.split('/')[-1]
+
   def Is(self, descriptor):
     """Checks if this Any represents the given protobuf type."""
-    # Only last part is to be used: b/25630112
-    return self.type_url.split('/')[-1] == descriptor.full_name
+    return self.TypeName() == descriptor.full_name
 
 
 class Timestamp(object):
diff --git a/python/google/protobuf/internal/well_known_types_test.py b/python/google/protobuf/internal/well_known_types_test.py
index 18329205..2f32ac99 100644
--- a/python/google/protobuf/internal/well_known_types_test.py
+++ b/python/google/protobuf/internal/well_known_types_test.py
@@ -610,6 +610,14 @@ class AnyTest(unittest.TestCase):
       raise AttributeError('%s should not have Pack method.' %
                            msg_descriptor.full_name)
 
+  def testMessageName(self):
+    # Creates and sets message.
+    submessage = any_test_pb2.TestAny()
+    submessage.int_value = 12345
+    msg = any_pb2.Any()
+    msg.Pack(submessage)
+    self.assertEqual(msg.TypeName(), 'google.protobuf.internal.TestAny')
+
   def testPackWithCustomTypeUrl(self):
     submessage = any_test_pb2.TestAny()
     submessage.int_value = 12345
diff --git a/python/google/protobuf/message.py b/python/google/protobuf/message.py
index de2f5697..606f735f 100755
--- a/python/google/protobuf/message.py
+++ b/python/google/protobuf/message.py
@@ -255,6 +255,9 @@ class Message(object):
   def ClearExtension(self, extension_handle):
     raise NotImplementedError
 
+  def DiscardUnknownFields(self):
+    raise NotImplementedError
+
   def ByteSize(self):
     """Returns the serialized size of this message.
     Recursively calls ByteSize() on all contained messages.
diff --git a/python/google/protobuf/pyext/descriptor.cc b/python/google/protobuf/pyext/descriptor.cc
index 07550706..23557538 100644
--- a/python/google/protobuf/pyext/descriptor.cc
+++ b/python/google/protobuf/pyext/descriptor.cc
@@ -200,8 +200,8 @@ static PyObject* GetOrBuildOptions(const DescriptorClass *descriptor) {
   // read-only instance.
   const Message& options(descriptor->options());
   const Descriptor *message_type = options.GetDescriptor();
-  PyObject* message_class(cdescriptor_pool::GetMessageClass(
-      pool, message_type));
+  CMessageClass* message_class(
+      cdescriptor_pool::GetMessageClass(pool, message_type));
   if (message_class == NULL) {
     // The Options message was not found in the current DescriptorPool.
     // In this case, there cannot be extensions to these options, and we can
@@ -215,7 +215,8 @@ static PyObject* GetOrBuildOptions(const DescriptorClass *descriptor) {
                  message_type->full_name().c_str());
     return NULL;
   }
-  ScopedPyObjectPtr value(PyEval_CallObject(message_class, NULL));
+  ScopedPyObjectPtr value(
+      PyEval_CallObject(message_class->AsPyObject(), NULL));
   if (value == NULL) {
     return NULL;
   }
@@ -433,11 +434,11 @@ static PyObject* GetConcreteClass(PyBaseDescriptor* self, void *closure) {
   // which contains this descriptor.
   // This might not be the one you expect! For example the returned object does
   // not know about extensions defined in a custom pool.
-  PyObject* concrete_class(cdescriptor_pool::GetMessageClass(
+  CMessageClass* concrete_class(cdescriptor_pool::GetMessageClass(
       GetDescriptorPool_FromPool(_GetDescriptor(self)->file()->pool()),
       _GetDescriptor(self)));
   Py_XINCREF(concrete_class);
-  return concrete_class;
+  return concrete_class->AsPyObject();
 }
 
 static PyObject* GetFieldsByName(PyBaseDescriptor* self, void *closure) {
diff --git a/python/google/protobuf/pyext/descriptor_pool.cc b/python/google/protobuf/pyext/descriptor_pool.cc
index 0bc76bc9..1faff96b 100644
--- a/python/google/protobuf/pyext/descriptor_pool.cc
+++ b/python/google/protobuf/pyext/descriptor_pool.cc
@@ -190,8 +190,8 @@ PyObject* FindMessageByName(PyDescriptorPool* self, PyObject* arg) {
 
 // Add a message class to our database.
 int RegisterMessageClass(PyDescriptorPool* self,
-                         const Descriptor *message_descriptor,
-                         PyObject *message_class) {
+                         const Descriptor* message_descriptor,
+                         CMessageClass* message_class) {
   Py_INCREF(message_class);
   typedef PyDescriptorPool::ClassesByMessageMap::iterator iterator;
   std::pair<iterator, bool> ret = self->classes_by_descriptor->insert(
@@ -205,8 +205,8 @@ int RegisterMessageClass(PyDescriptorPool* self,
 }
 
 // Retrieve the message class added to our database.
-PyObject *GetMessageClass(PyDescriptorPool* self,
-                          const Descriptor *message_descriptor) {
+CMessageClass* GetMessageClass(PyDescriptorPool* self,
+                               const Descriptor* message_descriptor) {
   typedef PyDescriptorPool::ClassesByMessageMap::iterator iterator;
   iterator ret = self->classes_by_descriptor->find(message_descriptor);
   if (ret == self->classes_by_descriptor->end()) {
diff --git a/python/google/protobuf/pyext/descriptor_pool.h b/python/google/protobuf/pyext/descriptor_pool.h
index 16bc910c..2a42c112 100644
--- a/python/google/protobuf/pyext/descriptor_pool.h
+++ b/python/google/protobuf/pyext/descriptor_pool.h
@@ -42,6 +42,9 @@ class MessageFactory;
 
 namespace python {
 
+// The (meta) type of all Messages classes.
+struct CMessageClass;
+
 // Wraps operations to the global DescriptorPool which contains information
 // about all messages and fields.
 //
@@ -78,7 +81,7 @@ typedef struct PyDescriptorPool {
   //
   // Descriptor pointers stored here are owned by the DescriptorPool above.
   // Python references to classes are owned by this PyDescriptorPool.
-  typedef hash_map<const Descriptor*, PyObject*> ClassesByMessageMap;
+  typedef hash_map<const Descriptor*, CMessageClass*> ClassesByMessageMap;
   ClassesByMessageMap* classes_by_descriptor;
 
   // Cache the options for any kind of descriptor.
@@ -101,14 +104,14 @@ const Descriptor* FindMessageTypeByName(PyDescriptorPool* self,
 // On error, returns -1 with a Python exception set.
 int RegisterMessageClass(PyDescriptorPool* self,
                          const Descriptor* message_descriptor,
-                         PyObject* message_class);
+                         CMessageClass* message_class);
 
 // Retrieves the Python class registered with the given message descriptor.
 //
 // Returns a *borrowed* reference if found, otherwise returns NULL with an
 // exception set.
-PyObject* GetMessageClass(PyDescriptorPool* self,
-                          const Descriptor* message_descriptor);
+CMessageClass* GetMessageClass(PyDescriptorPool* self,
+                               const Descriptor* message_descriptor);
 
 // The functions below are also exposed as methods of the DescriptorPool type.
 
diff --git a/python/google/protobuf/pyext/extension_dict.cc b/python/google/protobuf/pyext/extension_dict.cc
index 555bd293..21bbb8c2 100644
--- a/python/google/protobuf/pyext/extension_dict.cc
+++ b/python/google/protobuf/pyext/extension_dict.cc
@@ -130,7 +130,7 @@ PyObject* subscript(ExtensionDict* self, PyObject* key) {
 
   if (descriptor->label() == FieldDescriptor::LABEL_REPEATED) {
     if (descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      PyObject *message_class = cdescriptor_pool::GetMessageClass(
+      CMessageClass* message_class = cdescriptor_pool::GetMessageClass(
           cmessage::GetDescriptorPoolForMessage(self->parent),
           descriptor->message_type());
       if (message_class == NULL) {
@@ -239,6 +239,21 @@ PyObject* _FindExtensionByName(ExtensionDict* self, PyObject* name) {
   }
 }
 
+PyObject* _FindExtensionByNumber(ExtensionDict* self, PyObject* number) {
+  ScopedPyObjectPtr extensions_by_number(PyObject_GetAttrString(
+      reinterpret_cast<PyObject*>(self->parent), "_extensions_by_number"));
+  if (extensions_by_number == NULL) {
+    return NULL;
+  }
+  PyObject* result = PyDict_GetItem(extensions_by_number.get(), number);
+  if (result == NULL) {
+    Py_RETURN_NONE;
+  } else {
+    Py_INCREF(result);
+    return result;
+  }
+}
+
 ExtensionDict* NewExtensionDict(CMessage *parent) {
   ExtensionDict* self = reinterpret_cast<ExtensionDict*>(
       PyType_GenericAlloc(&ExtensionDict_Type, 0));
@@ -271,6 +286,8 @@ static PyMethodDef Methods[] = {
   EDMETHOD(HasExtension, METH_O, "Checks if the object has an extension."),
   EDMETHOD(_FindExtensionByName, METH_O,
            "Finds an extension by name."),
+  EDMETHOD(_FindExtensionByNumber, METH_O,
+           "Finds an extension by field number."),
   { NULL, NULL }
 };
 
diff --git a/python/google/protobuf/pyext/extension_dict.h b/python/google/protobuf/pyext/extension_dict.h
index 1e7f6f7b..049d2e45 100644
--- a/python/google/protobuf/pyext/extension_dict.h
+++ b/python/google/protobuf/pyext/extension_dict.h
@@ -123,6 +123,12 @@ PyObject* ClearExtension(ExtensionDict* self,
 // Returns a new reference.
 PyObject* _FindExtensionByName(ExtensionDict* self, PyObject* name);
 
+// Gets an extension from the dict given the extension field number as
+// opposed to descriptor.
+//
+// Returns a new reference.
+PyObject* _FindExtensionByNumber(ExtensionDict* self, PyObject* number);
+
 }  // namespace extension_dict
 }  // namespace python
 }  // namespace protobuf
diff --git a/python/google/protobuf/pyext/map_container.cc b/python/google/protobuf/pyext/map_container.cc
index df9138a4..e022406d 100644
--- a/python/google/protobuf/pyext/map_container.cc
+++ b/python/google/protobuf/pyext/map_container.cc
@@ -32,6 +32,11 @@
 
 #include <google/protobuf/pyext/map_container.h>
 
+#include <memory>
+#ifndef _SHARED_PTR_H
+#include <google/protobuf/stubs/shared_ptr.h>
+#endif
+
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/scoped_ptr.h>
@@ -70,7 +75,7 @@ class MapReflectionFriend {
 struct MapIterator {
   PyObject_HEAD;
 
-  scoped_ptr< ::google::protobuf::MapIterator> iter;
+  google::protobuf::scoped_ptr< ::google::protobuf::MapIterator> iter;
 
   // A pointer back to the container, so we can notice changes to the version.
   // We own a ref on this.
@@ -610,8 +615,7 @@ static PyObject* GetCMessage(MessageMapContainer* self, Message* message) {
   PyObject* ret = PyDict_GetItem(self->message_dict, key.get());
 
   if (ret == NULL) {
-    CMessage* cmsg = cmessage::NewEmptyMessage(self->subclass_init,
-                                               message->GetDescriptor());
+    CMessage* cmsg = cmessage::NewEmptyMessage(self->message_class);
     ret = reinterpret_cast<PyObject*>(cmsg);
 
     if (cmsg == NULL) {
@@ -634,7 +638,7 @@ static PyObject* GetCMessage(MessageMapContainer* self, Message* message) {
 
 PyObject* NewMessageMapContainer(
     CMessage* parent, const google::protobuf::FieldDescriptor* parent_field_descriptor,
-    PyObject* concrete_class) {
+    CMessageClass* message_class) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
     return NULL;
   }
@@ -669,8 +673,8 @@ PyObject* NewMessageMapContainer(
                         "Could not allocate message dict.");
   }
 
-  Py_INCREF(concrete_class);
-  self->subclass_init = concrete_class;
+  Py_INCREF(message_class);
+  self->message_class = message_class;
 
   if (self->key_field_descriptor == NULL ||
       self->value_field_descriptor == NULL) {
@@ -763,6 +767,7 @@ static void MessageMapDealloc(PyObject* _self) {
   MessageMapContainer* self = GetMessageMap(_self);
   self->owner.reset();
   Py_DECREF(self->message_dict);
+  Py_DECREF(self->message_class);
   Py_TYPE(_self)->tp_free(_self);
 }
 
diff --git a/python/google/protobuf/pyext/map_container.h b/python/google/protobuf/pyext/map_container.h
index 27ee6dbd..b11dfa34 100644
--- a/python/google/protobuf/pyext/map_container.h
+++ b/python/google/protobuf/pyext/map_container.h
@@ -55,6 +55,7 @@ using internal::shared_ptr;
 namespace python {
 
 struct CMessage;
+struct CMessageClass;
 
 // This struct is used directly for ScalarMap, and is the base class of
 // MessageMapContainer, which is used for MessageMap.
@@ -104,8 +105,8 @@ struct MapContainer {
 };
 
 struct MessageMapContainer : public MapContainer {
-  // A callable that is used to create new child messages.
-  PyObject* subclass_init;
+  // The type used to create new child messages.
+  CMessageClass* message_class;
 
   // A dict mapping Message* -> CMessage.
   PyObject* message_dict;
@@ -132,7 +133,7 @@ extern PyObject* NewScalarMapContainer(
 // field descriptor.
 extern PyObject* NewMessageMapContainer(
     CMessage* parent, const FieldDescriptor* parent_field_descriptor,
-    PyObject* concrete_class);
+    CMessageClass* message_class);
 
 }  // namespace python
 }  // namespace protobuf
diff --git a/python/google/protobuf/pyext/message.cc b/python/google/protobuf/pyext/message.cc
index 6d7b2b0f..83c151ff 100644
--- a/python/google/protobuf/pyext/message.cc
+++ b/python/google/protobuf/pyext/message.cc
@@ -98,31 +98,6 @@ static PyObject* PythonMessage_class;
 static PyObject* kEmptyWeakref;
 static PyObject* WKT_classes = NULL;
 
-// Defines the Metaclass of all Message classes.
-// It allows us to cache some C++ pointers in the class object itself, they are
-// faster to extract than from the type's dictionary.
-
-struct PyMessageMeta {
-  // This is how CPython subclasses C structures: the base structure must be
-  // the first member of the object.
-  PyHeapTypeObject super;
-
-  // C++ descriptor of this message.
-  const Descriptor* message_descriptor;
-
-  // Owned reference, used to keep the pointer above alive.
-  PyObject* py_message_descriptor;
-
-  // The Python DescriptorPool used to create the class. It is needed to resolve
-  // fields descriptors, including extensions fields; its C++ MessageFactory is
-  // used to instantiate submessages.
-  // This can be different from DESCRIPTOR.file.pool, in the case of a custom
-  // DescriptorPool which defines new extensions.
-  // We own the reference, because it's important to keep the descriptors and
-  // factory alive.
-  PyDescriptorPool* py_descriptor_pool;
-};
-
 namespace message_meta {
 
 static int InsertEmptyWeakref(PyTypeObject* base);
@@ -173,10 +148,6 @@ static int AddDescriptors(PyObject* cls, const Descriptor* descriptor) {
   }
 
   // For each enum set cls.<enum name> = EnumTypeWrapper(<enum descriptor>).
-  //
-  // The enum descriptor we get from
-  // <messagedescriptor>.enum_types_by_name[name]
-  // which was built previously.
   for (int i = 0; i < descriptor->enum_type_count(); ++i) {
     const EnumDescriptor* enum_descriptor = descriptor->enum_type(i);
     ScopedPyObjectPtr enum_type(
@@ -309,7 +280,7 @@ static PyObject* New(PyTypeObject* type,
   if (result == NULL) {
     return NULL;
   }
-  PyMessageMeta* newtype = reinterpret_cast<PyMessageMeta*>(result.get());
+  CMessageClass* newtype = reinterpret_cast<CMessageClass*>(result.get());
 
   // Insert the empty weakref into the base classes.
   if (InsertEmptyWeakref(
@@ -338,7 +309,7 @@ static PyObject* New(PyTypeObject* type,
 
   // Add the message to the DescriptorPool.
   if (cdescriptor_pool::RegisterMessageClass(newtype->py_descriptor_pool,
-                                             descriptor, result.get()) < 0) {
+                                             descriptor, newtype) < 0) {
     return NULL;
   }
 
@@ -349,7 +320,7 @@ static PyObject* New(PyTypeObject* type,
   return result.release();
 }
 
-static void Dealloc(PyMessageMeta *self) {
+static void Dealloc(CMessageClass *self) {
   Py_DECREF(self->py_message_descriptor);
   Py_DECREF(self->py_descriptor_pool);
   Py_TYPE(self)->tp_free(reinterpret_cast<PyObject*>(self));
@@ -378,10 +349,10 @@ static int InsertEmptyWeakref(PyTypeObject *base_type) {
 
 }  // namespace message_meta
 
-PyTypeObject PyMessageMeta_Type = {
+PyTypeObject CMessageClass_Type = {
   PyVarObject_HEAD_INIT(&PyType_Type, 0)
   FULL_MODULE_NAME ".MessageMeta",     // tp_name
-  sizeof(PyMessageMeta),               // tp_basicsize
+  sizeof(CMessageClass),               // tp_basicsize
   0,                                   // tp_itemsize
   (destructor)message_meta::Dealloc,   // tp_dealloc
   0,                                   // tp_print
@@ -419,16 +390,16 @@ PyTypeObject PyMessageMeta_Type = {
   message_meta::New,                   // tp_new
 };
 
-static PyMessageMeta* CheckMessageClass(PyTypeObject* cls) {
-  if (!PyObject_TypeCheck(cls, &PyMessageMeta_Type)) {
+static CMessageClass* CheckMessageClass(PyTypeObject* cls) {
+  if (!PyObject_TypeCheck(cls, &CMessageClass_Type)) {
     PyErr_Format(PyExc_TypeError, "Class %s is not a Message", cls->tp_name);
     return NULL;
   }
-  return reinterpret_cast<PyMessageMeta*>(cls);
+  return reinterpret_cast<CMessageClass*>(cls);
 }
 
 static const Descriptor* GetMessageDescriptor(PyTypeObject* cls) {
-  PyMessageMeta* type = CheckMessageClass(cls);
+  CMessageClass* type = CheckMessageClass(cls);
   if (type == NULL) {
     return NULL;
   }
@@ -783,9 +754,9 @@ namespace cmessage {
 
 PyDescriptorPool* GetDescriptorPoolForMessage(CMessage* message) {
   // No need to check the type: the type of instances of CMessage is always
-  // an instance of PyMessageMeta. Let's prove it with a debug-only check.
+  // an instance of CMessageClass. Let's prove it with a debug-only check.
   GOOGLE_DCHECK(PyObject_TypeCheck(message, &CMessage_Type));
-  return reinterpret_cast<PyMessageMeta*>(Py_TYPE(message))->py_descriptor_pool;
+  return reinterpret_cast<CMessageClass*>(Py_TYPE(message))->py_descriptor_pool;
 }
 
 MessageFactory* GetFactoryForMessage(CMessage* message) {
@@ -1090,6 +1061,10 @@ int InitAttributes(CMessage* self, PyObject* kwargs) {
                    PyString_AsString(name));
       return -1;
     }
+    if (value == Py_None) {
+      // field=None is the same as no field at all.
+      continue;
+    }
     if (descriptor->is_map()) {
       ScopedPyObjectPtr map(GetAttr(self, name));
       const FieldDescriptor* value_descriptor =
@@ -1220,9 +1195,9 @@ int InitAttributes(CMessage* self, PyObject* kwargs) {
 
 // Allocates an incomplete Python Message: the caller must fill self->message,
 // self->owner and eventually self->parent.
-CMessage* NewEmptyMessage(PyObject* type, const Descriptor *descriptor) {
+CMessage* NewEmptyMessage(CMessageClass* type) {
   CMessage* self = reinterpret_cast<CMessage*>(
-      PyType_GenericAlloc(reinterpret_cast<PyTypeObject*>(type), 0));
+      PyType_GenericAlloc(&type->super.ht_type, 0));
   if (self == NULL) {
     return NULL;
   }
@@ -1242,7 +1217,7 @@ CMessage* NewEmptyMessage(PyObject* type, const Descriptor *descriptor) {
 // Creates a new C++ message and takes ownership.
 static PyObject* New(PyTypeObject* cls,
                      PyObject* unused_args, PyObject* unused_kwargs) {
-  PyMessageMeta* type = CheckMessageClass(cls);
+  CMessageClass* type = CheckMessageClass(cls);
   if (type == NULL) {
     return NULL;
   }
@@ -1258,8 +1233,7 @@ static PyObject* New(PyTypeObject* cls,
     return NULL;
   }
 
-  CMessage* self = NewEmptyMessage(reinterpret_cast<PyObject*>(type),
-                                   message_descriptor);
+  CMessage* self = NewEmptyMessage(type);
   if (self == NULL) {
     return NULL;
   }
@@ -2023,10 +1997,34 @@ static PyObject* RegisterExtension(PyObject* cls,
     PyErr_SetString(PyExc_TypeError, "no extensions_by_number on class");
     return NULL;
   }
+
   ScopedPyObjectPtr number(PyObject_GetAttrString(extension_handle, "number"));
   if (number == NULL) {
     return NULL;
   }
+
+  // If the extension was already registered by number, check that it is the
+  // same.
+  existing_extension = PyDict_GetItem(extensions_by_number.get(), number.get());
+  if (existing_extension != NULL) {
+    const FieldDescriptor* existing_extension_descriptor =
+        GetExtensionDescriptor(existing_extension);
+    if (existing_extension_descriptor != descriptor) {
+      const Descriptor* msg_desc = GetMessageDescriptor(
+          reinterpret_cast<PyTypeObject*>(cls));
+      PyErr_Format(
+          PyExc_ValueError,
+          "Extensions \"%s\" and \"%s\" both try to extend message type "
+          "\"%s\" with field number %ld.",
+          existing_extension_descriptor->full_name().c_str(),
+          descriptor->full_name().c_str(),
+          msg_desc->full_name().c_str(),
+          PyInt_AsLong(number.get()));
+      return NULL;
+    }
+    // Nothing else to do.
+    Py_RETURN_NONE;
+  }
   if (PyDict_SetItem(extensions_by_number.get(), number.get(),
                      extension_handle) < 0) {
     return NULL;
@@ -2166,6 +2164,12 @@ static PyObject* ListFields(CMessage* self) {
   return all_fields.release();
 }
 
+static PyObject* DiscardUnknownFields(CMessage* self) {
+  AssureWritable(self);
+  self->message->DiscardUnknownFields();
+  Py_RETURN_NONE;
+}
+
 PyObject* FindInitializationErrors(CMessage* self) {
   Message* message = self->message;
   vector<string> errors;
@@ -2309,14 +2313,13 @@ PyObject* InternalGetSubMessage(
   const Message& sub_message = reflection->GetMessage(
       *self->message, field_descriptor, pool->message_factory);
 
-  PyObject *message_class = cdescriptor_pool::GetMessageClass(
+  CMessageClass* message_class = cdescriptor_pool::GetMessageClass(
       pool, field_descriptor->message_type());
   if (message_class == NULL) {
     return NULL;
   }
 
-  CMessage* cmsg = cmessage::NewEmptyMessage(message_class,
-                                             sub_message.GetDescriptor());
+  CMessage* cmsg = cmessage::NewEmptyMessage(message_class);
   if (cmsg == NULL) {
     return NULL;
   }
@@ -2585,6 +2588,8 @@ static PyMethodDef Methods[] = {
     "Clears a message field." },
   { "CopyFrom", (PyCFunction)CopyFrom, METH_O,
     "Copies a protocol message into the current message." },
+  { "DiscardUnknownFields", (PyCFunction)DiscardUnknownFields, METH_NOARGS,
+    "Discards the unknown fields." },
   { "FindInitializationErrors", (PyCFunction)FindInitializationErrors,
     METH_NOARGS,
     "Finds unset required fields." },
@@ -2654,7 +2659,7 @@ PyObject* GetAttr(CMessage* self, PyObject* name) {
     const Descriptor* entry_type = field_descriptor->message_type();
     const FieldDescriptor* value_type = entry_type->FindFieldByName("value");
     if (value_type->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      PyObject* value_class = cdescriptor_pool::GetMessageClass(
+      CMessageClass* value_class = cdescriptor_pool::GetMessageClass(
           GetDescriptorPoolForMessage(self), value_type->message_type());
       if (value_class == NULL) {
         return NULL;
@@ -2677,7 +2682,7 @@ PyObject* GetAttr(CMessage* self, PyObject* name) {
   if (field_descriptor->label() == FieldDescriptor::LABEL_REPEATED) {
     PyObject* py_container = NULL;
     if (field_descriptor->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE) {
-      PyObject *message_class = cdescriptor_pool::GetMessageClass(
+      CMessageClass* message_class = cdescriptor_pool::GetMessageClass(
           GetDescriptorPoolForMessage(self), field_descriptor->message_type());
       if (message_class == NULL) {
         return NULL;
@@ -2749,7 +2754,7 @@ int SetAttr(CMessage* self, PyObject* name, PyObject* value) {
 }  // namespace cmessage
 
 PyTypeObject CMessage_Type = {
-  PyVarObject_HEAD_INIT(&PyMessageMeta_Type, 0)
+  PyVarObject_HEAD_INIT(&CMessageClass_Type, 0)
   FULL_MODULE_NAME ".CMessage",        // tp_name
   sizeof(CMessage),                    // tp_basicsize
   0,                                   //  tp_itemsize
@@ -2864,12 +2869,12 @@ bool InitProto2MessageModule(PyObject *m) {
   // Initialize constants defined in this file.
   InitGlobals();
 
-  PyMessageMeta_Type.tp_base = &PyType_Type;
-  if (PyType_Ready(&PyMessageMeta_Type) < 0) {
+  CMessageClass_Type.tp_base = &PyType_Type;
+  if (PyType_Ready(&CMessageClass_Type) < 0) {
     return false;
   }
   PyModule_AddObject(m, "MessageMeta",
-                     reinterpret_cast<PyObject*>(&PyMessageMeta_Type));
+                     reinterpret_cast<PyObject*>(&CMessageClass_Type));
 
   if (PyType_Ready(&CMessage_Type) < 0) {
     return false;
@@ -3077,9 +3082,10 @@ bool InitProto2MessageModule(PyObject *m) {
 }  // namespace protobuf
 
 static PyMethodDef ModuleMethods[] = {
-    {"SetAllowOversizeProtos",
-     (PyCFunction)google::protobuf::python::cmessage::SetAllowOversizeProtos,
-     METH_O, "Enable/disable oversize proto parsing."},
+  {"SetAllowOversizeProtos",
+    (PyCFunction)google::protobuf::python::cmessage::SetAllowOversizeProtos,
+    METH_O, "Enable/disable oversize proto parsing."},
+  { NULL, NULL}
 };
 
 #if PY_MAJOR_VERSION >= 3
diff --git a/python/google/protobuf/pyext/message.h b/python/google/protobuf/pyext/message.h
index c2b62649..9dce198f 100644
--- a/python/google/protobuf/pyext/message.h
+++ b/python/google/protobuf/pyext/message.h
@@ -116,12 +116,43 @@ typedef struct CMessage {
 
 extern PyTypeObject CMessage_Type;
 
+
+// The (meta) type of all Messages classes.
+// It allows us to cache some C++ pointers in the class object itself, they are
+// faster to extract than from the type's dictionary.
+
+struct CMessageClass {
+  // This is how CPython subclasses C structures: the base structure must be
+  // the first member of the object.
+  PyHeapTypeObject super;
+
+  // C++ descriptor of this message.
+  const Descriptor* message_descriptor;
+
+  // Owned reference, used to keep the pointer above alive.
+  PyObject* py_message_descriptor;
+
+  // The Python DescriptorPool used to create the class. It is needed to resolve
+  // fields descriptors, including extensions fields; its C++ MessageFactory is
+  // used to instantiate submessages.
+  // This can be different from DESCRIPTOR.file.pool, in the case of a custom
+  // DescriptorPool which defines new extensions.
+  // We own the reference, because it's important to keep the descriptors and
+  // factory alive.
+  PyDescriptorPool* py_descriptor_pool;
+
+  PyObject* AsPyObject() {
+    return reinterpret_cast<PyObject*>(this);
+  }
+};
+
+
 namespace cmessage {
 
 // Internal function to create a new empty Message Python object, but with empty
 // pointers to the C++ objects.
 // The caller must fill self->message, self->owner and eventually self->parent.
-CMessage* NewEmptyMessage(PyObject* type, const Descriptor* descriptor);
+CMessage* NewEmptyMessage(CMessageClass* type);
 
 // Release a submessage from its proto tree, making it a new top-level messgae.
 // A new message will be created if this is a read-only default instance.
diff --git a/python/google/protobuf/pyext/repeated_composite_container.cc b/python/google/protobuf/pyext/repeated_composite_container.cc
index b01123b4..4f339e77 100644
--- a/python/google/protobuf/pyext/repeated_composite_container.cc
+++ b/python/google/protobuf/pyext/repeated_composite_container.cc
@@ -107,8 +107,7 @@ static int UpdateChildMessages(RepeatedCompositeContainer* self) {
   for (Py_ssize_t i = child_length; i < message_length; ++i) {
     const Message& sub_message = reflection->GetRepeatedMessage(
         *(self->message), self->parent_field_descriptor, i);
-    CMessage* cmsg = cmessage::NewEmptyMessage(self->subclass_init,
-                                               sub_message.GetDescriptor());
+    CMessage* cmsg = cmessage::NewEmptyMessage(self->child_message_class);
     ScopedPyObjectPtr py_cmsg(reinterpret_cast<PyObject*>(cmsg));
     if (cmsg == NULL) {
       return -1;
@@ -140,8 +139,7 @@ static PyObject* AddToAttached(RepeatedCompositeContainer* self,
   Message* sub_message =
       message->GetReflection()->AddMessage(message,
                                            self->parent_field_descriptor);
-  CMessage* cmsg = cmessage::NewEmptyMessage(self->subclass_init,
-                                             sub_message->GetDescriptor());
+  CMessage* cmsg = cmessage::NewEmptyMessage(self->child_message_class);
   if (cmsg == NULL)
     return NULL;
 
@@ -168,7 +166,7 @@ static PyObject* AddToReleased(RepeatedCompositeContainer* self,
 
   // Create a new Message detached from the rest.
   PyObject* py_cmsg = PyEval_CallObjectWithKeywords(
-      self->subclass_init, NULL, kwargs);
+      self->child_message_class->AsPyObject(), NULL, kwargs);
   if (py_cmsg == NULL)
     return NULL;
 
@@ -506,7 +504,7 @@ int SetOwner(RepeatedCompositeContainer* self,
 PyObject *NewContainer(
     CMessage* parent,
     const FieldDescriptor* parent_field_descriptor,
-    PyObject *concrete_class) {
+    CMessageClass* concrete_class) {
   if (!CheckFieldBelongsToMessage(parent_field_descriptor, parent->message)) {
     return NULL;
   }
@@ -523,7 +521,7 @@ PyObject *NewContainer(
   self->parent_field_descriptor = parent_field_descriptor;
   self->owner = parent->owner;
   Py_INCREF(concrete_class);
-  self->subclass_init = concrete_class;
+  self->child_message_class = concrete_class;
   self->child_messages = PyList_New(0);
 
   return reinterpret_cast<PyObject*>(self);
@@ -531,7 +529,7 @@ PyObject *NewContainer(
 
 static void Dealloc(RepeatedCompositeContainer* self) {
   Py_CLEAR(self->child_messages);
-  Py_CLEAR(self->subclass_init);
+  Py_CLEAR(self->child_message_class);
   // TODO(tibell): Do we need to call delete on these objects to make
   // sure their destructors are called?
   self->owner.reset();
diff --git a/python/google/protobuf/pyext/repeated_composite_container.h b/python/google/protobuf/pyext/repeated_composite_container.h
index 442ce7e3..25463037 100644
--- a/python/google/protobuf/pyext/repeated_composite_container.h
+++ b/python/google/protobuf/pyext/repeated_composite_container.h
@@ -58,6 +58,7 @@ using internal::shared_ptr;
 namespace python {
 
 struct CMessage;
+struct CMessageClass;
 
 // A RepeatedCompositeContainer can be in one of two states: attached
 // or released.
@@ -94,8 +95,8 @@ typedef struct RepeatedCompositeContainer {
   // calling Clear() or ClearField() on the parent.
   Message* message;
 
-  // A callable that is used to create new child messages.
-  PyObject* subclass_init;
+  // The type used to create new child messages.
+  CMessageClass* child_message_class;
 
   // A list of child messages.
   PyObject* child_messages;
@@ -110,7 +111,7 @@ namespace repeated_composite_container {
 PyObject *NewContainer(
     CMessage* parent,
     const FieldDescriptor* parent_field_descriptor,
-    PyObject *concrete_class);
+    CMessageClass *child_message_class);
 
 // Appends a new CMessage to the container and returns it.  The
 // CMessage is initialized using the content of kwargs.
diff --git a/python/google/protobuf/text_format.py b/python/google/protobuf/text_format.py
index a6f41ca8..6f1e3c8b 100755
--- a/python/google/protobuf/text_format.py
+++ b/python/google/protobuf/text_format.py
@@ -99,7 +99,7 @@ class TextWriter(object):
 
 def MessageToString(message, as_utf8=False, as_one_line=False,
                     pointy_brackets=False, use_index_order=False,
-                    float_format=None):
+                    float_format=None, use_field_number=False):
   """Convert protobuf message to text format.
 
   Floating point values can be formatted compactly with 15 digits of
@@ -118,15 +118,16 @@ def MessageToString(message, as_utf8=False, as_one_line=False,
       field number order.
     float_format: If set, use this to specify floating point number formatting
       (per the "Format Specification Mini-Language"); otherwise, str() is used.
+    use_field_number: If True, print field numbers instead of names.
 
   Returns:
     A string of the text formatted protocol buffer message.
   """
   out = TextWriter(as_utf8)
-  PrintMessage(message, out, as_utf8=as_utf8, as_one_line=as_one_line,
-               pointy_brackets=pointy_brackets,
-               use_index_order=use_index_order,
-               float_format=float_format)
+  printer = _Printer(out, 0, as_utf8, as_one_line,
+                     pointy_brackets, use_index_order, float_format,
+                     use_field_number)
+  printer.PrintMessage(message)
   result = out.getvalue()
   out.close()
   if as_one_line:
@@ -142,133 +143,187 @@ def _IsMapEntry(field):
 
 def PrintMessage(message, out, indent=0, as_utf8=False, as_one_line=False,
                  pointy_brackets=False, use_index_order=False,
-                 float_format=None):
-  fields = message.ListFields()
-  if use_index_order:
-    fields.sort(key=lambda x: x[0].index)
-  for field, value in fields:
-    if _IsMapEntry(field):
-      for key in sorted(value):
-        # This is slow for maps with submessage entires because it copies the
-        # entire tree.  Unfortunately this would take significant refactoring
-        # of this file to work around.
-        #
-        # TODO(haberman): refactor and optimize if this becomes an issue.
-        entry_submsg = field.message_type._concrete_class(
-            key=key, value=value[key])
-        PrintField(field, entry_submsg, out, indent, as_utf8, as_one_line,
-                   pointy_brackets=pointy_brackets,
-                   use_index_order=use_index_order, float_format=float_format)
-    elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
-      for element in value:
-        PrintField(field, element, out, indent, as_utf8, as_one_line,
-                   pointy_brackets=pointy_brackets,
-                   use_index_order=use_index_order,
-                   float_format=float_format)
-    else:
-      PrintField(field, value, out, indent, as_utf8, as_one_line,
-                 pointy_brackets=pointy_brackets,
-                 use_index_order=use_index_order,
-                 float_format=float_format)
+                 float_format=None, use_field_number=False):
+  printer = _Printer(out, indent, as_utf8, as_one_line,
+                     pointy_brackets, use_index_order, float_format,
+                     use_field_number)
+  printer.PrintMessage(message)
 
 
 def PrintField(field, value, out, indent=0, as_utf8=False, as_one_line=False,
                pointy_brackets=False, use_index_order=False, float_format=None):
-  """Print a single field name/value pair.  For repeated fields, the value
-  should be a single element.
-  """
-
-  out.write(' ' * indent)
-  if field.is_extension:
-    out.write('[')
-    if (field.containing_type.GetOptions().message_set_wire_format and
-        field.type == descriptor.FieldDescriptor.TYPE_MESSAGE and
-        field.label == descriptor.FieldDescriptor.LABEL_OPTIONAL):
-      out.write(field.message_type.full_name)
-    else:
-      out.write(field.full_name)
-    out.write(']')
-  elif field.type == descriptor.FieldDescriptor.TYPE_GROUP:
-    # For groups, use the capitalized name.
-    out.write(field.message_type.name)
-  else:
-    out.write(field.name)
-
-  if field.cpp_type != descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
-    # The colon is optional in this case, but our cross-language golden files
-    # don't include it.
-    out.write(': ')
-
-  PrintFieldValue(field, value, out, indent, as_utf8, as_one_line,
-                  pointy_brackets=pointy_brackets,
-                  use_index_order=use_index_order,
-                  float_format=float_format)
-  if as_one_line:
-    out.write(' ')
-  else:
-    out.write('\n')
+  """Print a single field name/value pair."""
+  printer = _Printer(out, indent, as_utf8, as_one_line,
+                     pointy_brackets, use_index_order, float_format)
+  printer.PrintField(field, value)
 
 
 def PrintFieldValue(field, value, out, indent=0, as_utf8=False,
                     as_one_line=False, pointy_brackets=False,
                     use_index_order=False,
                     float_format=None):
-  """Print a single field value (not including name).  For repeated fields,
-  the value should be a single element."""
+  """Print a single field value (not including name)."""
+  printer = _Printer(out, indent, as_utf8, as_one_line,
+                     pointy_brackets, use_index_order, float_format)
+  printer.PrintFieldValue(field, value)
 
-  if pointy_brackets:
-    openb = '<'
-    closeb = '>'
-  else:
-    openb = '{'
-    closeb = '}'
-
-  if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
-    if as_one_line:
-      out.write(' %s ' % openb)
-      PrintMessage(value, out, indent, as_utf8, as_one_line,
-                   pointy_brackets=pointy_brackets,
-                   use_index_order=use_index_order,
-                   float_format=float_format)
-      out.write(closeb)
-    else:
-      out.write(' %s\n' % openb)
-      PrintMessage(value, out, indent + 2, as_utf8, as_one_line,
-                   pointy_brackets=pointy_brackets,
-                   use_index_order=use_index_order,
-                   float_format=float_format)
-      out.write(' ' * indent + closeb)
-  elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_ENUM:
-    enum_value = field.enum_type.values_by_number.get(value, None)
-    if enum_value is not None:
-      out.write(enum_value.name)
+
+class _Printer(object):
+  """Text format printer for protocol message."""
+
+  def __init__(self, out, indent=0, as_utf8=False, as_one_line=False,
+               pointy_brackets=False, use_index_order=False, float_format=None,
+               use_field_number=False):
+    """Initialize the Printer.
+
+    Floating point values can be formatted compactly with 15 digits of
+    precision (which is the most that IEEE 754 "double" can guarantee)
+    using float_format='.15g'. To ensure that converting to text and back to a
+    proto will result in an identical value, float_format='.17g' should be used.
+
+    Args:
+      out: To record the text format result.
+      indent: The indent level for pretty print.
+      as_utf8: Produce text output in UTF8 format.
+      as_one_line: Don't introduce newlines between fields.
+      pointy_brackets: If True, use angle brackets instead of curly braces for
+        nesting.
+      use_index_order: If True, print fields of a proto message using the order
+        defined in source code instead of the field number. By default, use the
+        field number order.
+      float_format: If set, use this to specify floating point number formatting
+        (per the "Format Specification Mini-Language"); otherwise, str() is
+        used.
+      use_field_number: If True, print field numbers instead of names.
+    """
+    self.out = out
+    self.indent = indent
+    self.as_utf8 = as_utf8
+    self.as_one_line = as_one_line
+    self.pointy_brackets = pointy_brackets
+    self.use_index_order = use_index_order
+    self.float_format = float_format
+    self.use_field_number = use_field_number
+
+  def PrintMessage(self, message):
+    """Convert protobuf message to text format.
+
+    Args:
+      message: The protocol buffers message.
+    """
+    fields = message.ListFields()
+    if self.use_index_order:
+      fields.sort(key=lambda x: x[0].index)
+    for field, value in fields:
+      if _IsMapEntry(field):
+        for key in sorted(value):
+          # This is slow for maps with submessage entires because it copies the
+          # entire tree.  Unfortunately this would take significant refactoring
+          # of this file to work around.
+          #
+          # TODO(haberman): refactor and optimize if this becomes an issue.
+          entry_submsg = field.message_type._concrete_class(
+              key=key, value=value[key])
+          self.PrintField(field, entry_submsg)
+      elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+        for element in value:
+          self.PrintField(field, element)
+      else:
+        self.PrintField(field, value)
+
+  def PrintField(self, field, value):
+    """Print a single field name/value pair."""
+    out = self.out
+    out.write(' ' * self.indent)
+    if self.use_field_number:
+      out.write(str(field.number))
     else:
-      out.write(str(value))
-  elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
-    out.write('\"')
-    if isinstance(value, six.text_type):
-      out_value = value.encode('utf-8')
+      if field.is_extension:
+        out.write('[')
+        if (field.containing_type.GetOptions().message_set_wire_format and
+            field.type == descriptor.FieldDescriptor.TYPE_MESSAGE and
+            field.label == descriptor.FieldDescriptor.LABEL_OPTIONAL):
+          out.write(field.message_type.full_name)
+        else:
+          out.write(field.full_name)
+        out.write(']')
+      elif field.type == descriptor.FieldDescriptor.TYPE_GROUP:
+        # For groups, use the capitalized name.
+        out.write(field.message_type.name)
+      else:
+        out.write(field.name)
+
+    if field.cpp_type != descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+      # The colon is optional in this case, but our cross-language golden files
+      # don't include it.
+      out.write(': ')
+
+    self.PrintFieldValue(field, value)
+    if self.as_one_line:
+      out.write(' ')
     else:
-      out_value = value
-    if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
-      # We need to escape non-UTF8 chars in TYPE_BYTES field.
-      out_as_utf8 = False
+      out.write('\n')
+
+  def PrintFieldValue(self, field, value):
+    """Print a single field value (not including name).
+
+    For repeated fields, the value should be a single element.
+
+    Args:
+      field: The descriptor of the field to be printed.
+      value: The value of the field.
+    """
+    out = self.out
+    if self.pointy_brackets:
+      openb = '<'
+      closeb = '>'
     else:
-      out_as_utf8 = as_utf8
-    out.write(text_encoding.CEscape(out_value, out_as_utf8))
-    out.write('\"')
-  elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
-    if value:
-      out.write('true')
+      openb = '{'
+      closeb = '}'
+
+    if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+      if self.as_one_line:
+        out.write(' %s ' % openb)
+        self.PrintMessage(value)
+        out.write(closeb)
+      else:
+        out.write(' %s\n' % openb)
+        self.indent += 2
+        self.PrintMessage(value)
+        self.indent -= 2
+        out.write(' ' * self.indent + closeb)
+    elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_ENUM:
+      enum_value = field.enum_type.values_by_number.get(value, None)
+      if enum_value is not None:
+        out.write(enum_value.name)
+      else:
+        out.write(str(value))
+    elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
+      out.write('\"')
+      if isinstance(value, six.text_type):
+        out_value = value.encode('utf-8')
+      else:
+        out_value = value
+      if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
+        # We need to escape non-UTF8 chars in TYPE_BYTES field.
+        out_as_utf8 = False
+      else:
+        out_as_utf8 = self.as_utf8
+      out.write(text_encoding.CEscape(out_value, out_as_utf8))
+      out.write('\"')
+    elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
+      if value:
+        out.write('true')
+      else:
+        out.write('false')
+    elif field.cpp_type in _FLOAT_TYPES and self.float_format is not None:
+      out.write('{1:{0}}'.format(self.float_format, value))
     else:
-      out.write('false')
-  elif field.cpp_type in _FLOAT_TYPES and float_format is not None:
-    out.write('{1:{0}}'.format(float_format, value))
-  else:
-    out.write(str(value))
+      out.write(str(value))
 
 
-def Parse(text, message, allow_unknown_extension=False):
+def Parse(text, message,
+          allow_unknown_extension=False, allow_field_number=False):
   """Parses an text representation of a protocol message into a message.
 
   Args:
@@ -276,6 +331,7 @@ def Parse(text, message, allow_unknown_extension=False):
     message: A protocol buffer message to merge into.
     allow_unknown_extension: if True, skip over missing extensions and keep
       parsing
+    allow_field_number: if True, both field number and field name are allowed.
 
   Returns:
     The same message passed as argument.
@@ -285,10 +341,12 @@ def Parse(text, message, allow_unknown_extension=False):
   """
   if not isinstance(text, str):
     text = text.decode('utf-8')
-  return ParseLines(text.split('\n'), message, allow_unknown_extension)
+  return ParseLines(text.split('\n'), message, allow_unknown_extension,
+                    allow_field_number)
 
 
-def Merge(text, message, allow_unknown_extension=False):
+def Merge(text, message, allow_unknown_extension=False,
+          allow_field_number=False):
   """Parses an text representation of a protocol message into a message.
 
   Like Parse(), but allows repeated values for a non-repeated field, and uses
@@ -299,6 +357,7 @@ def Merge(text, message, allow_unknown_extension=False):
     message: A protocol buffer message to merge into.
     allow_unknown_extension: if True, skip over missing extensions and keep
       parsing
+    allow_field_number: if True, both field number and field name are allowed.
 
   Returns:
     The same message passed as argument.
@@ -306,10 +365,12 @@ def Merge(text, message, allow_unknown_extension=False):
   Raises:
     ParseError: On text parsing problems.
   """
-  return MergeLines(text.split('\n'), message, allow_unknown_extension)
+  return MergeLines(text.split('\n'), message, allow_unknown_extension,
+                    allow_field_number)
 
 
-def ParseLines(lines, message, allow_unknown_extension=False):
+def ParseLines(lines, message, allow_unknown_extension=False,
+               allow_field_number=False):
   """Parses an text representation of a protocol message into a message.
 
   Args:
@@ -317,6 +378,7 @@ def ParseLines(lines, message, allow_unknown_extension=False):
     message: A protocol buffer message to merge into.
     allow_unknown_extension: if True, skip over missing extensions and keep
       parsing
+    allow_field_number: if True, both field number and field name are allowed.
 
   Returns:
     The same message passed as argument.
@@ -324,11 +386,12 @@ def ParseLines(lines, message, allow_unknown_extension=False):
   Raises:
     ParseError: On text parsing problems.
   """
-  _ParseOrMerge(lines, message, False, allow_unknown_extension)
-  return message
+  parser = _Parser(allow_unknown_extension, allow_field_number)
+  return parser.ParseLines(lines, message)
 
 
-def MergeLines(lines, message, allow_unknown_extension=False):
+def MergeLines(lines, message, allow_unknown_extension=False,
+               allow_field_number=False):
   """Parses an text representation of a protocol message into a message.
 
   Args:
@@ -336,6 +399,7 @@ def MergeLines(lines, message, allow_unknown_extension=False):
     message: A protocol buffer message to merge into.
     allow_unknown_extension: if True, skip over missing extensions and keep
       parsing
+    allow_field_number: if True, both field number and field name are allowed.
 
   Returns:
     The same message passed as argument.
@@ -343,146 +407,272 @@ def MergeLines(lines, message, allow_unknown_extension=False):
   Raises:
     ParseError: On text parsing problems.
   """
-  _ParseOrMerge(lines, message, True, allow_unknown_extension)
-  return message
+  parser = _Parser(allow_unknown_extension, allow_field_number)
+  return parser.MergeLines(lines, message)
 
 
-def _ParseOrMerge(lines,
-                  message,
-                  allow_multiple_scalars,
-                  allow_unknown_extension=False):
-  """Converts an text representation of a protocol message into a message.
+class _Parser(object):
+  """Text format parser for protocol message."""
 
-  Args:
-    lines: Lines of a message's text representation.
-    message: A protocol buffer message to merge into.
-    allow_multiple_scalars: Determines if repeated values for a non-repeated
-      field are permitted, e.g., the string "foo: 1 foo: 2" for a
-      required/optional field named "foo".
-    allow_unknown_extension: if True, skip over missing extensions and keep
-      parsing
+  def __init__(self, allow_unknown_extension=False, allow_field_number=False):
+    self.allow_unknown_extension = allow_unknown_extension
+    self.allow_field_number = allow_field_number
 
-  Raises:
-    ParseError: On text parsing problems.
-  """
-  tokenizer = _Tokenizer(lines)
-  while not tokenizer.AtEnd():
-    _MergeField(tokenizer, message, allow_multiple_scalars,
-                allow_unknown_extension)
+  def ParseFromString(self, text, message):
+    """Parses an text representation of a protocol message into a message."""
+    if not isinstance(text, str):
+      text = text.decode('utf-8')
+    return self.ParseLines(text.split('\n'), message)
 
+  def ParseLines(self, lines, message):
+    """Parses an text representation of a protocol message into a message."""
+    self._allow_multiple_scalars = False
+    self._ParseOrMerge(lines, message)
+    return message
 
-def _MergeField(tokenizer,
-                message,
-                allow_multiple_scalars,
-                allow_unknown_extension=False):
-  """Merges a single protocol message field into a message.
+  def MergeFromString(self, text, message):
+    """Merges an text representation of a protocol message into a message."""
+    return self._MergeLines(text.split('\n'), message)
 
-  Args:
-    tokenizer: A tokenizer to parse the field name and values.
-    message: A protocol message to record the data.
-    allow_multiple_scalars: Determines if repeated values for a non-repeated
-      field are permitted, e.g., the string "foo: 1 foo: 2" for a
-      required/optional field named "foo".
-    allow_unknown_extension: if True, skip over missing extensions and keep
-      parsing.
+  def MergeLines(self, lines, message):
+    """Merges an text representation of a protocol message into a message."""
+    self._allow_multiple_scalars = True
+    self._ParseOrMerge(lines, message)
+    return message
 
-  Raises:
-    ParseError: In case of text parsing problems.
-  """
-  message_descriptor = message.DESCRIPTOR
-  if (hasattr(message_descriptor, 'syntax') and
-      message_descriptor.syntax == 'proto3'):
-    # Proto3 doesn't represent presence so we can't test if multiple
-    # scalars have occurred.  We have to allow them.
-    allow_multiple_scalars = True
-  if tokenizer.TryConsume('['):
-    name = [tokenizer.ConsumeIdentifier()]
-    while tokenizer.TryConsume('.'):
-      name.append(tokenizer.ConsumeIdentifier())
-    name = '.'.join(name)
-
-    if not message_descriptor.is_extendable:
-      raise tokenizer.ParseErrorPreviousToken(
-          'Message type "%s" does not have extensions.' %
-          message_descriptor.full_name)
-    # pylint: disable=protected-access
-    field = message.Extensions._FindExtensionByName(name)
-    # pylint: enable=protected-access
-    if not field:
-      if allow_unknown_extension:
-        field = None
-      else:
-        raise tokenizer.ParseErrorPreviousToken(
-            'Extension "%s" not registered.' % name)
-    elif message_descriptor != field.containing_type:
-      raise tokenizer.ParseErrorPreviousToken(
-          'Extension "%s" does not extend message type "%s".' % (
-              name, message_descriptor.full_name))
+  def _ParseOrMerge(self, lines, message):
+    """Converts an text representation of a protocol message into a message.
 
-    tokenizer.Consume(']')
+    Args:
+      lines: Lines of a message's text representation.
+      message: A protocol buffer message to merge into.
 
-  else:
-    name = tokenizer.ConsumeIdentifier()
-    field = message_descriptor.fields_by_name.get(name, None)
-
-    # Group names are expected to be capitalized as they appear in the
-    # .proto file, which actually matches their type names, not their field
-    # names.
-    if not field:
-      field = message_descriptor.fields_by_name.get(name.lower(), None)
-      if field and field.type != descriptor.FieldDescriptor.TYPE_GROUP:
-        field = None
-
-    if (field and field.type == descriptor.FieldDescriptor.TYPE_GROUP and
-        field.message_type.name != name):
-      field = None
-
-    if not field:
-      raise tokenizer.ParseErrorPreviousToken(
-          'Message type "%s" has no field named "%s".' % (
-              message_descriptor.full_name, name))
-
-  if field:
-    if not allow_multiple_scalars and field.containing_oneof:
-      # Check if there's a different field set in this oneof.
-      # Note that we ignore the case if the same field was set before, and we
-      # apply allow_multiple_scalars to non-scalar fields as well.
-      which_oneof = message.WhichOneof(field.containing_oneof.name)
-      if which_oneof is not None and which_oneof != field.name:
+    Raises:
+      ParseError: On text parsing problems.
+    """
+    tokenizer = _Tokenizer(lines)
+    while not tokenizer.AtEnd():
+      self._MergeField(tokenizer, message)
+
+  def _MergeField(self, tokenizer, message):
+    """Merges a single protocol message field into a message.
+
+    Args:
+      tokenizer: A tokenizer to parse the field name and values.
+      message: A protocol message to record the data.
+
+    Raises:
+      ParseError: In case of text parsing problems.
+    """
+    message_descriptor = message.DESCRIPTOR
+    if (hasattr(message_descriptor, 'syntax') and
+        message_descriptor.syntax == 'proto3'):
+      # Proto3 doesn't represent presence so we can't test if multiple
+      # scalars have occurred.  We have to allow them.
+      self._allow_multiple_scalars = True
+    if tokenizer.TryConsume('['):
+      name = [tokenizer.ConsumeIdentifier()]
+      while tokenizer.TryConsume('.'):
+        name.append(tokenizer.ConsumeIdentifier())
+      name = '.'.join(name)
+
+      if not message_descriptor.is_extendable:
+        raise tokenizer.ParseErrorPreviousToken(
+            'Message type "%s" does not have extensions.' %
+            message_descriptor.full_name)
+      # pylint: disable=protected-access
+      field = message.Extensions._FindExtensionByName(name)
+      # pylint: enable=protected-access
+      if not field:
+        if self.allow_unknown_extension:
+          field = None
+        else:
+          raise tokenizer.ParseErrorPreviousToken(
+              'Extension "%s" not registered.' % name)
+      elif message_descriptor != field.containing_type:
         raise tokenizer.ParseErrorPreviousToken(
-            'Field "%s" is specified along with field "%s", another member of '
-            'oneof "%s" for message type "%s".' % (
-                field.name, which_oneof, field.containing_oneof.name,
-                message_descriptor.full_name))
+            'Extension "%s" does not extend message type "%s".' % (
+                name, message_descriptor.full_name))
+
+      tokenizer.Consume(']')
 
-    if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
-      tokenizer.TryConsume(':')
-      merger = _MergeMessageField
     else:
-      tokenizer.Consume(':')
-      merger = _MergeScalarField
-
-    if (field.label == descriptor.FieldDescriptor.LABEL_REPEATED
-        and tokenizer.TryConsume('[')):
-      # Short repeated format, e.g. "foo: [1, 2, 3]"
-      while True:
-        merger(tokenizer, message, field, allow_multiple_scalars,
-               allow_unknown_extension)
-        if tokenizer.TryConsume(']'): break
-        tokenizer.Consume(',')
+      name = tokenizer.ConsumeIdentifier()
+      if self.allow_field_number and name.isdigit():
+        number = ParseInteger(name, True, True)
+        field = message_descriptor.fields_by_number.get(number, None)
+        if not field and message_descriptor.is_extendable:
+          field = message.Extensions._FindExtensionByNumber(number)
+      else:
+        field = message_descriptor.fields_by_name.get(name, None)
+
+        # Group names are expected to be capitalized as they appear in the
+        # .proto file, which actually matches their type names, not their field
+        # names.
+        if not field:
+          field = message_descriptor.fields_by_name.get(name.lower(), None)
+          if field and field.type != descriptor.FieldDescriptor.TYPE_GROUP:
+            field = None
+
+        if (field and field.type == descriptor.FieldDescriptor.TYPE_GROUP and
+            field.message_type.name != name):
+          field = None
+
+      if not field:
+        raise tokenizer.ParseErrorPreviousToken(
+            'Message type "%s" has no field named "%s".' % (
+                message_descriptor.full_name, name))
+
+    if field:
+      if not self._allow_multiple_scalars and field.containing_oneof:
+        # Check if there's a different field set in this oneof.
+        # Note that we ignore the case if the same field was set before, and we
+        # apply _allow_multiple_scalars to non-scalar fields as well.
+        which_oneof = message.WhichOneof(field.containing_oneof.name)
+        if which_oneof is not None and which_oneof != field.name:
+          raise tokenizer.ParseErrorPreviousToken(
+              'Field "%s" is specified along with field "%s", another member '
+              'of oneof "%s" for message type "%s".' % (
+                  field.name, which_oneof, field.containing_oneof.name,
+                  message_descriptor.full_name))
+
+      if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+        tokenizer.TryConsume(':')
+        merger = self._MergeMessageField
+      else:
+        tokenizer.Consume(':')
+        merger = self._MergeScalarField
+
+      if (field.label == descriptor.FieldDescriptor.LABEL_REPEATED
+          and tokenizer.TryConsume('[')):
+        # Short repeated format, e.g. "foo: [1, 2, 3]"
+        while True:
+          merger(tokenizer, message, field)
+          if tokenizer.TryConsume(']'): break
+          tokenizer.Consume(',')
+
+      else:
+        merger(tokenizer, message, field)
+
+    else:  # Proto field is unknown.
+      assert self.allow_unknown_extension
+      _SkipFieldContents(tokenizer)
+
+    # For historical reasons, fields may optionally be separated by commas or
+    # semicolons.
+    if not tokenizer.TryConsume(','):
+      tokenizer.TryConsume(';')
+
+  def _MergeMessageField(self, tokenizer, message, field):
+    """Merges a single scalar field into a message.
+
+    Args:
+      tokenizer: A tokenizer to parse the field value.
+      message: The message of which field is a member.
+      field: The descriptor of the field to be merged.
+
+    Raises:
+      ParseError: In case of text parsing problems.
+    """
+    is_map_entry = _IsMapEntry(field)
 
+    if tokenizer.TryConsume('<'):
+      end_token = '>'
     else:
-      merger(tokenizer, message, field, allow_multiple_scalars,
-             allow_unknown_extension)
+      tokenizer.Consume('{')
+      end_token = '}'
+
+    if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+      if field.is_extension:
+        sub_message = message.Extensions[field].add()
+      elif is_map_entry:
+        # pylint: disable=protected-access
+        sub_message = field.message_type._concrete_class()
+      else:
+        sub_message = getattr(message, field.name).add()
+    else:
+      if field.is_extension:
+        sub_message = message.Extensions[field]
+      else:
+        sub_message = getattr(message, field.name)
+      sub_message.SetInParent()
+
+    while not tokenizer.TryConsume(end_token):
+      if tokenizer.AtEnd():
+        raise tokenizer.ParseErrorPreviousToken('Expected "%s".' % (end_token,))
+      self._MergeField(tokenizer, sub_message)
+
+    if is_map_entry:
+      value_cpptype = field.message_type.fields_by_name['value'].cpp_type
+      if value_cpptype == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
+        value = getattr(message, field.name)[sub_message.key]
+        value.MergeFrom(sub_message.value)
+      else:
+        getattr(message, field.name)[sub_message.key] = sub_message.value
 
-  else:  # Proto field is unknown.
-    assert allow_unknown_extension
-    _SkipFieldContents(tokenizer)
+  def _MergeScalarField(self, tokenizer, message, field):
+    """Merges a single scalar field into a message.
 
-  # For historical reasons, fields may optionally be separated by commas or
-  # semicolons.
-  if not tokenizer.TryConsume(','):
-    tokenizer.TryConsume(';')
+    Args:
+      tokenizer: A tokenizer to parse the field value.
+      message: A protocol message to record the data.
+      field: The descriptor of the field to be merged.
+
+    Raises:
+      ParseError: In case of text parsing problems.
+      RuntimeError: On runtime errors.
+    """
+    _ = self.allow_unknown_extension
+    value = None
+
+    if field.type in (descriptor.FieldDescriptor.TYPE_INT32,
+                      descriptor.FieldDescriptor.TYPE_SINT32,
+                      descriptor.FieldDescriptor.TYPE_SFIXED32):
+      value = tokenizer.ConsumeInt32()
+    elif field.type in (descriptor.FieldDescriptor.TYPE_INT64,
+                        descriptor.FieldDescriptor.TYPE_SINT64,
+                        descriptor.FieldDescriptor.TYPE_SFIXED64):
+      value = tokenizer.ConsumeInt64()
+    elif field.type in (descriptor.FieldDescriptor.TYPE_UINT32,
+                        descriptor.FieldDescriptor.TYPE_FIXED32):
+      value = tokenizer.ConsumeUint32()
+    elif field.type in (descriptor.FieldDescriptor.TYPE_UINT64,
+                        descriptor.FieldDescriptor.TYPE_FIXED64):
+      value = tokenizer.ConsumeUint64()
+    elif field.type in (descriptor.FieldDescriptor.TYPE_FLOAT,
+                        descriptor.FieldDescriptor.TYPE_DOUBLE):
+      value = tokenizer.ConsumeFloat()
+    elif field.type == descriptor.FieldDescriptor.TYPE_BOOL:
+      value = tokenizer.ConsumeBool()
+    elif field.type == descriptor.FieldDescriptor.TYPE_STRING:
+      value = tokenizer.ConsumeString()
+    elif field.type == descriptor.FieldDescriptor.TYPE_BYTES:
+      value = tokenizer.ConsumeByteString()
+    elif field.type == descriptor.FieldDescriptor.TYPE_ENUM:
+      value = tokenizer.ConsumeEnum(field)
+    else:
+      raise RuntimeError('Unknown field type %d' % field.type)
+
+    if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
+      if field.is_extension:
+        message.Extensions[field].append(value)
+      else:
+        getattr(message, field.name).append(value)
+    else:
+      if field.is_extension:
+        if not self._allow_multiple_scalars and message.HasExtension(field):
+          raise tokenizer.ParseErrorPreviousToken(
+              'Message type "%s" should not have multiple "%s" extensions.' %
+              (message.DESCRIPTOR.full_name, field.full_name))
+        else:
+          message.Extensions[field] = value
+      else:
+        if not self._allow_multiple_scalars and message.HasField(field.name):
+          raise tokenizer.ParseErrorPreviousToken(
+              'Message type "%s" should not have multiple "%s" fields.' %
+              (message.DESCRIPTOR.full_name, field.name))
+        else:
+          setattr(message, field.name, value)
 
 
 def _SkipFieldContents(tokenizer):
@@ -555,10 +745,10 @@ def _SkipFieldValue(tokenizer):
   Raises:
     ParseError: In case an invalid field value is found.
   """
-  # String tokens can come in multiple adjacent string literals.
+  # String/bytes tokens can come in multiple adjacent string literals.
   # If we can consume one, consume as many as we can.
-  if tokenizer.TryConsumeString():
-    while tokenizer.TryConsumeString():
+  if tokenizer.TryConsumeByteString():
+    while tokenizer.TryConsumeByteString():
       pass
     return
 
@@ -569,132 +759,6 @@ def _SkipFieldValue(tokenizer):
     raise ParseError('Invalid field value: ' + tokenizer.token)
 
 
-def _MergeMessageField(tokenizer, message, field, allow_multiple_scalars,
-                       allow_unknown_extension):
-  """Merges a single scalar field into a message.
-
-  Args:
-    tokenizer: A tokenizer to parse the field value.
-    message: The message of which field is a member.
-    field: The descriptor of the field to be merged.
-    allow_multiple_scalars: Determines if repeated values for a non-repeated
-      field are permitted, e.g., the string "foo: 1 foo: 2" for a
-      required/optional field named "foo".
-    allow_unknown_extension: if True, skip over missing extensions and keep
-      parsing.
-
-  Raises:
-    ParseError: In case of text parsing problems.
-  """
-  is_map_entry = _IsMapEntry(field)
-
-  if tokenizer.TryConsume('<'):
-    end_token = '>'
-  else:
-    tokenizer.Consume('{')
-    end_token = '}'
-
-  if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
-    if field.is_extension:
-      sub_message = message.Extensions[field].add()
-    elif is_map_entry:
-      # pylint: disable=protected-access
-      sub_message = field.message_type._concrete_class()
-    else:
-      sub_message = getattr(message, field.name).add()
-  else:
-    if field.is_extension:
-      sub_message = message.Extensions[field]
-    else:
-      sub_message = getattr(message, field.name)
-    sub_message.SetInParent()
-
-  while not tokenizer.TryConsume(end_token):
-    if tokenizer.AtEnd():
-      raise tokenizer.ParseErrorPreviousToken('Expected "%s".' % (end_token,))
-    _MergeField(tokenizer, sub_message, allow_multiple_scalars,
-                allow_unknown_extension)
-
-  if is_map_entry:
-    value_cpptype = field.message_type.fields_by_name['value'].cpp_type
-    if value_cpptype == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
-      value = getattr(message, field.name)[sub_message.key]
-      value.MergeFrom(sub_message.value)
-    else:
-      getattr(message, field.name)[sub_message.key] = sub_message.value
-
-
-def _MergeScalarField(tokenizer, message, field, allow_multiple_scalars,
-                      allow_unknown_extension):
-  """Merges a single scalar field into a message.
-
-  Args:
-    tokenizer: A tokenizer to parse the field value.
-    message: A protocol message to record the data.
-    field: The descriptor of the field to be merged.
-    allow_multiple_scalars: Determines if repeated values for a non-repeated
-      field are permitted, e.g., the string "foo: 1 foo: 2" for a
-      required/optional field named "foo".
-    allow_unknown_extension: Unused, just here for consistency with
-      _MergeMessageField.
-
-  Raises:
-    ParseError: In case of text parsing problems.
-    RuntimeError: On runtime errors.
-  """
-  _ = allow_unknown_extension
-  value = None
-
-  if field.type in (descriptor.FieldDescriptor.TYPE_INT32,
-                    descriptor.FieldDescriptor.TYPE_SINT32,
-                    descriptor.FieldDescriptor.TYPE_SFIXED32):
-    value = tokenizer.ConsumeInt32()
-  elif field.type in (descriptor.FieldDescriptor.TYPE_INT64,
-                      descriptor.FieldDescriptor.TYPE_SINT64,
-                      descriptor.FieldDescriptor.TYPE_SFIXED64):
-    value = tokenizer.ConsumeInt64()
-  elif field.type in (descriptor.FieldDescriptor.TYPE_UINT32,
-                      descriptor.FieldDescriptor.TYPE_FIXED32):
-    value = tokenizer.ConsumeUint32()
-  elif field.type in (descriptor.FieldDescriptor.TYPE_UINT64,
-                      descriptor.FieldDescriptor.TYPE_FIXED64):
-    value = tokenizer.ConsumeUint64()
-  elif field.type in (descriptor.FieldDescriptor.TYPE_FLOAT,
-                      descriptor.FieldDescriptor.TYPE_DOUBLE):
-    value = tokenizer.ConsumeFloat()
-  elif field.type == descriptor.FieldDescriptor.TYPE_BOOL:
-    value = tokenizer.ConsumeBool()
-  elif field.type == descriptor.FieldDescriptor.TYPE_STRING:
-    value = tokenizer.ConsumeString()
-  elif field.type == descriptor.FieldDescriptor.TYPE_BYTES:
-    value = tokenizer.ConsumeByteString()
-  elif field.type == descriptor.FieldDescriptor.TYPE_ENUM:
-    value = tokenizer.ConsumeEnum(field)
-  else:
-    raise RuntimeError('Unknown field type %d' % field.type)
-
-  if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
-    if field.is_extension:
-      message.Extensions[field].append(value)
-    else:
-      getattr(message, field.name).append(value)
-  else:
-    if field.is_extension:
-      if not allow_multiple_scalars and message.HasExtension(field):
-        raise tokenizer.ParseErrorPreviousToken(
-            'Message type "%s" should not have multiple "%s" extensions.' %
-            (message.DESCRIPTOR.full_name, field.full_name))
-      else:
-        message.Extensions[field] = value
-    else:
-      if not allow_multiple_scalars and message.HasField(field.name):
-        raise tokenizer.ParseErrorPreviousToken(
-            'Message type "%s" should not have multiple "%s" fields.' %
-            (message.DESCRIPTOR.full_name, field.name))
-      else:
-        setattr(message, field.name, value)
-
-
 class _Tokenizer(object):
   """Protocol buffer text representation tokenizer.
 
@@ -925,9 +989,9 @@ class _Tokenizer(object):
     self.NextToken()
     return result
 
-  def TryConsumeString(self):
+  def TryConsumeByteString(self):
     try:
-      self.ConsumeString()
+      self.ConsumeByteString()
       return True
     except ParseError:
       return False
diff --git a/ruby/Gemfile.lock b/ruby/Gemfile.lock
index 27e57506..d0eb9cc4 100644
--- a/ruby/Gemfile.lock
+++ b/ruby/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    google-protobuf (3.0.0.alpha.5.0)
+    google-protobuf (3.0.0.alpha.5.0.5)
 
 GEM
   remote: https://rubygems.org/
diff --git a/ruby/README.md b/ruby/README.md
index 16474322..f28e05a7 100644
--- a/ruby/README.md
+++ b/ruby/README.md
@@ -32,23 +32,25 @@ documentation may be found in the RubyDoc comments (`call-seq` tags) in the
 source, and we plan to release separate, more detailed, documentation at a
 later date.
 
-    require 'google/protobuf'
+```ruby
+require 'google/protobuf'
 
-    # generated from my_proto_types.proto with protoc:
-    #  $ protoc --ruby_out=. my_proto_types.proto
-    require 'my_proto_types'
+# generated from my_proto_types.proto with protoc:
+#  $ protoc --ruby_out=. my_proto_types.proto
+require 'my_proto_types'
 
-    mymessage = MyTestMessage.new(:field1 => 42, :field2 => ["a", "b", "c"])
-    mymessage.field1 = 43
-    mymessage.field2.push("d")
-    mymessage.field3 = SubMessage.new(:foo => 100)
+mymessage = MyTestMessage.new(:field1 => 42, :field2 => ["a", "b", "c"])
+mymessage.field1 = 43
+mymessage.field2.push("d")
+mymessage.field3 = SubMessage.new(:foo => 100)
 
-    encoded_data = MyTestMessage.encode(mymessage)
-    decoded = MyTestMessage.decode(encoded_data)
-    assert decoded == mymessage
+encoded_data = MyTestMessage.encode(mymessage)
+decoded = MyTestMessage.decode(encoded_data)
+assert decoded == mymessage
 
-    puts "JSON:"
-    puts MyTestMessage.encode_json(mymessage)
+puts "JSON:"
+puts MyTestMessage.encode_json(mymessage)
+```
 
 Installation from Source (Building Gem)
 ---------------------------------------
diff --git a/ruby/Rakefile b/ruby/Rakefile
index 8eb7a2df..fa29c315 100644
--- a/ruby/Rakefile
+++ b/ruby/Rakefile
@@ -5,6 +5,40 @@ require "rake/testtask"
 
 spec = Gem::Specification.load("google-protobuf.gemspec")
 
+well_known_protos = %w[
+  google/protobuf/any.proto
+  google/protobuf/api.proto
+  google/protobuf/duration.proto
+  google/protobuf/empty.proto
+  google/protobuf/field_mask.proto
+  google/protobuf/source_context.proto
+  google/protobuf/struct.proto
+  google/protobuf/timestamp.proto
+  google/protobuf/type.proto
+  google/protobuf/wrappers.proto
+]
+
+# These are omitted for now because we don't support proto2.
+proto2_protos = %w[
+  google/protobuf/descriptor.proto
+  google/protobuf/compiler/plugin.proto
+]
+
+genproto_output = []
+
+# We won't have access to .. from within docker, but the proto files
+# will be there, thanks to the :genproto rule dependency for gem:native.
+unless ENV['IN_DOCKER'] == 'true'
+  well_known_protos.each do |proto_file|
+    input_file = "../src/" + proto_file
+    output_file = "lib/" + proto_file.sub(/\.proto$/, ".rb")
+    genproto_output << output_file
+    file output_file => input_file do |file_task|
+      sh "../src/protoc -I../src --ruby_out=lib #{input_file}"
+    end
+  end
+end
+
 if RUBY_PLATFORM == "java"
   if `which mvn` == ''
     raise ArgumentError, "maven needs to be installed"
@@ -30,37 +64,16 @@ else
 
   task 'gem:windows' do
     require 'rake_compiler_dock'
-    RakeCompilerDock.sh "bundle && rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.6"
+    RakeCompilerDock.sh "bundle && IN_DOCKER=true rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.5:2.0.0"
   end
-end
-
-well_known_protos = %w[
-  google/protobuf/any.proto
-  google/protobuf/api.proto
-  google/protobuf/duration.proto
-  google/protobuf/empty.proto
-  google/protobuf/field_mask.proto
-  google/protobuf/source_context.proto
-  google/protobuf/struct.proto
-  google/protobuf/timestamp.proto
-  google/protobuf/type.proto
-  google/protobuf/wrappers.proto
-]
-
-# These are omitted for now because we don't support proto2.
-proto2_protos = %w[
-  google/protobuf/descriptor.proto
-  google/protobuf/compiler/plugin.proto
-]
-
-genproto_output = []
 
-well_known_protos.each do |proto_file|
-  input_file = "../src/" + proto_file
-  output_file = "lib/" + proto_file.sub(/\.proto$/, ".rb")
-  genproto_output << output_file
-  file output_file => input_file do |file_task|
-    sh "../src/protoc -I../src --ruby_out=lib #{input_file}"
+  if RUBY_PLATFORM =~ /darwin/
+    task 'gem:native' do
+      system "rake genproto"
+      system "rake cross native gem RUBY_CC_VERSION=2.3.0:2.2.2:2.1.5:2.0.0"
+    end
+  else
+    task 'gem:native' => [:genproto, 'gem:windows']
   end
 end
 
diff --git a/ruby/ext/google/protobuf_c/defs.c b/ruby/ext/google/protobuf_c/defs.c
index 96ef4953..7e93bafb 100644
--- a/ruby/ext/google/protobuf_c/defs.c
+++ b/ruby/ext/google/protobuf_c/defs.c
@@ -255,6 +255,10 @@ void Descriptor_free(void* _self) {
     upb_handlers_unref(self->json_serialize_handlers,
                        &self->json_serialize_handlers);
   }
+  if (self->json_serialize_handlers_preserve) {
+    upb_handlers_unref(self->json_serialize_handlers_preserve,
+                       &self->json_serialize_handlers_preserve);
+  }
   xfree(self);
 }
 
@@ -278,6 +282,7 @@ VALUE Descriptor_alloc(VALUE klass) {
   self->json_fill_method = NULL;
   self->pb_serialize_handlers = NULL;
   self->json_serialize_handlers = NULL;
+  self->json_serialize_handlers_preserve = NULL;
   self->typeclass_references = rb_ary_new();
   return ret;
 }
diff --git a/ruby/ext/google/protobuf_c/encode_decode.c b/ruby/ext/google/protobuf_c/encode_decode.c
index c2c369eb..f6bea50f 100644
--- a/ruby/ext/google/protobuf_c/encode_decode.c
+++ b/ruby/ext/google/protobuf_c/encode_decode.c
@@ -656,7 +656,6 @@ static const upb_json_parsermethod *msgdef_jsonparsermethod(Descriptor* desc) {
 #define STACK_ENV_STACKBYTES 4096
 typedef struct {
   upb_env env;
-  upb_seededalloc alloc;
   const char* ruby_error_template;
   char allocbuf[STACK_ENV_STACKBYTES];
 } stackenv;
@@ -681,16 +680,12 @@ static bool env_error_func(void* ud, const upb_status* status) {
 
 static void stackenv_init(stackenv* se, const char* errmsg) {
   se->ruby_error_template = errmsg;
-  upb_env_init(&se->env);
-  upb_seededalloc_init(&se->alloc, &se->allocbuf, STACK_ENV_STACKBYTES);
-  upb_env_setallocfunc(
-      &se->env, upb_seededalloc_getallocfunc(&se->alloc), &se->alloc);
+  upb_env_init2(&se->env, se->allocbuf, sizeof(se->allocbuf), NULL);
   upb_env_seterrorfunc(&se->env, env_error_func, se);
 }
 
 static void stackenv_uninit(stackenv* se) {
   upb_env_uninit(&se->env);
-  upb_seededalloc_uninit(&se->alloc);
 }
 
 /*
@@ -1130,13 +1125,23 @@ static const upb_handlers* msgdef_pb_serialize_handlers(Descriptor* desc) {
   return desc->pb_serialize_handlers;
 }
 
-static const upb_handlers* msgdef_json_serialize_handlers(Descriptor* desc) {
-  if (desc->json_serialize_handlers == NULL) {
-    desc->json_serialize_handlers =
-        upb_json_printer_newhandlers(
-            desc->msgdef, &desc->json_serialize_handlers);
+static const upb_handlers* msgdef_json_serialize_handlers(
+    Descriptor* desc, bool preserve_proto_fieldnames) {
+  if (preserve_proto_fieldnames) {
+    if (desc->json_serialize_handlers == NULL) {
+      desc->json_serialize_handlers =
+          upb_json_printer_newhandlers(
+              desc->msgdef, true, &desc->json_serialize_handlers);
+    }
+    return desc->json_serialize_handlers;
+  } else {
+    if (desc->json_serialize_handlers_preserve == NULL) {
+      desc->json_serialize_handlers_preserve =
+          upb_json_printer_newhandlers(
+              desc->msgdef, false, &desc->json_serialize_handlers_preserve);
+    }
+    return desc->json_serialize_handlers_preserve;
   }
-  return desc->json_serialize_handlers;
 }
 
 /*
@@ -1181,16 +1186,33 @@ VALUE Message_encode(VALUE klass, VALUE msg_rb) {
  *
  * Encodes the given message object into its serialized JSON representation.
  */
-VALUE Message_encode_json(VALUE klass, VALUE msg_rb) {
+VALUE Message_encode_json(int argc, VALUE* argv, VALUE klass) {
   VALUE descriptor = rb_ivar_get(klass, descriptor_instancevar_interned);
   Descriptor* desc = ruby_to_Descriptor(descriptor);
-
+  VALUE msg_rb;
+  VALUE preserve_proto_fieldnames = Qfalse;
   stringsink sink;
+
+  if (argc < 1 || argc > 2) {
+    rb_raise(rb_eArgError, "Expected 1 or 2 arguments.");
+  }
+
+  msg_rb = argv[0];
+
+  if (argc == 2) {
+    VALUE hash_args = argv[1];
+    if (TYPE(hash_args) != T_HASH) {
+      rb_raise(rb_eArgError, "Expected hash arguments.");
+    }
+    preserve_proto_fieldnames = rb_hash_lookup2(
+        hash_args, ID2SYM(rb_intern("preserve_proto_fieldnames")), Qfalse);
+  }
+
   stringsink_init(&sink);
 
   {
     const upb_handlers* serialize_handlers =
-        msgdef_json_serialize_handlers(desc);
+        msgdef_json_serialize_handlers(desc, RTEST(preserve_proto_fieldnames));
     upb_json_printer* printer;
     stackenv se;
     VALUE ret;
diff --git a/ruby/ext/google/protobuf_c/message.c b/ruby/ext/google/protobuf_c/message.c
index 283939c9..e16250f3 100644
--- a/ruby/ext/google/protobuf_c/message.c
+++ b/ruby/ext/google/protobuf_c/message.c
@@ -151,32 +151,30 @@ VALUE Message_method_missing(int argc, VALUE* argv, VALUE _self) {
     name_len--;
   }
 
-  // Check for a oneof name first.
-  o = upb_msgdef_ntoo(self->descriptor->msgdef,
-                                          name, name_len);
+  // See if this name corresponds to either a oneof or field in this message.
+  if (!upb_msgdef_lookupname(self->descriptor->msgdef, name, name_len, &f,
+                             &o)) {
+    return rb_call_super(argc, argv);
+  }
+
   if (o != NULL) {
+    // This is a oneof -- return which field inside the oneof is set.
     if (setter) {
       rb_raise(rb_eRuntimeError, "Oneof accessors are read-only.");
     }
     return which_oneof_field(self, o);
-  }
-
-  // Otherwise, check for a field with that name.
-  f = upb_msgdef_ntof(self->descriptor->msgdef,
-                                          name, name_len);
-
-  if (f == NULL) {
-    return rb_call_super(argc, argv);
-  }
-
-  if (setter) {
-    if (argc < 2) {
-      rb_raise(rb_eArgError, "No value provided to setter.");
-    }
-    layout_set(self->descriptor->layout, Message_data(self), f, argv[1]);
-    return Qnil;
   } else {
-    return layout_get(self->descriptor->layout, Message_data(self), f);
+    // This is a field -- get or set the field's value.
+    assert(f);
+    if (setter) {
+      if (argc < 2) {
+        rb_raise(rb_eArgError, "No value provided to setter.");
+      }
+      layout_set(self->descriptor->layout, Message_data(self), f, argv[1]);
+      return Qnil;
+    } else {
+      return layout_get(self->descriptor->layout, Message_data(self), f);
+    }
   }
 }
 
@@ -475,7 +473,7 @@ VALUE build_class_from_descriptor(Descriptor* desc) {
   rb_define_singleton_method(klass, "decode", Message_decode, 1);
   rb_define_singleton_method(klass, "encode", Message_encode, 1);
   rb_define_singleton_method(klass, "decode_json", Message_decode_json, 1);
-  rb_define_singleton_method(klass, "encode_json", Message_encode_json, 1);
+  rb_define_singleton_method(klass, "encode_json", Message_encode_json, -1);
   rb_define_singleton_method(klass, "descriptor", Message_descriptor, 0);
 
   return klass;
diff --git a/ruby/ext/google/protobuf_c/protobuf.h b/ruby/ext/google/protobuf_c/protobuf.h
index 21ce7bb3..2834c894 100644
--- a/ruby/ext/google/protobuf_c/protobuf.h
+++ b/ruby/ext/google/protobuf_c/protobuf.h
@@ -115,6 +115,7 @@ struct Descriptor {
   const upb_json_parsermethod* json_fill_method;
   const upb_handlers* pb_serialize_handlers;
   const upb_handlers* json_serialize_handlers;
+  const upb_handlers* json_serialize_handlers_preserve;
   // Handlers hold type class references for sub-message fields directly in some
   // cases. We need to keep these rooted because they might otherwise be
   // collected.
@@ -498,7 +499,7 @@ VALUE Message_descriptor(VALUE klass);
 VALUE Message_decode(VALUE klass, VALUE data);
 VALUE Message_encode(VALUE klass, VALUE msg_rb);
 VALUE Message_decode_json(VALUE klass, VALUE data);
-VALUE Message_encode_json(VALUE klass, VALUE msg_rb);
+VALUE Message_encode_json(int argc, VALUE* argv, VALUE klass);
 
 VALUE Google_Protobuf_deep_copy(VALUE self, VALUE obj);
 
diff --git a/ruby/ext/google/protobuf_c/upb.c b/ruby/ext/google/protobuf_c/upb.c
index b2a69b66..74a2a1db 100644
--- a/ruby/ext/google/protobuf_c/upb.c
+++ b/ruby/ext/google/protobuf_c/upb.c
@@ -12,7 +12,7 @@ typedef struct {
 } str_t;
 
 static str_t *newstr(const char *data, size_t len) {
-  str_t *ret = malloc(sizeof(*ret) + len);
+  str_t *ret = upb_gmalloc(sizeof(*ret) + len);
   if (!ret) return NULL;
   ret->len = len;
   memcpy(ret->str, data, len);
@@ -20,7 +20,7 @@ static str_t *newstr(const char *data, size_t len) {
   return ret;
 }
 
-static void freestr(str_t *s) { free(s); }
+static void freestr(str_t *s) { upb_gfree(s); }
 
 /* isalpha() etc. from <ctype.h> are locale-dependent, which we don't want. */
 static bool upb_isbetween(char c, char low, char high) {
@@ -65,6 +65,22 @@ static bool upb_isident(const char *str, size_t len, bool full, upb_status *s) {
   return !start;
 }
 
+static bool upb_isoneof(const upb_refcounted *def) {
+  return def->vtbl == &upb_oneofdef_vtbl;
+}
+
+static bool upb_isfield(const upb_refcounted *def) {
+  return def->vtbl == &upb_fielddef_vtbl;
+}
+
+static const upb_oneofdef *upb_trygetoneof(const upb_refcounted *def) {
+  return upb_isoneof(def) ? (const upb_oneofdef*)def : NULL;
+}
+
+static const upb_fielddef *upb_trygetfield(const upb_refcounted *def) {
+  return upb_isfield(def) ? (const upb_fielddef*)def : NULL;
+}
+
 
 /* upb_def ********************************************************************/
 
@@ -72,14 +88,39 @@ upb_deftype_t upb_def_type(const upb_def *d) { return d->type; }
 
 const char *upb_def_fullname(const upb_def *d) { return d->fullname; }
 
+const char *upb_def_name(const upb_def *d) {
+  const char *p;
+
+  if (d->fullname == NULL) {
+    return NULL;
+  } else if ((p = strrchr(d->fullname, '.')) == NULL) {
+    /* No '.' in the name, return the full string. */
+    return d->fullname;
+  } else {
+    /* Return one past the last '.'. */
+    return p + 1;
+  }
+}
+
 bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s) {
   assert(!upb_def_isfrozen(def));
-  if (!upb_isident(fullname, strlen(fullname), true, s)) return false;
-  free((void*)def->fullname);
-  def->fullname = upb_strdup(fullname);
+  if (!upb_isident(fullname, strlen(fullname), true, s)) {
+    return false;
+  }
+
+  fullname = upb_gstrdup(fullname);
+  if (!fullname) {
+    upb_upberr_setoom(s);
+    return false;
+  }
+
+  upb_gfree((void*)def->fullname);
+  def->fullname = fullname;
   return true;
 }
 
+const upb_filedef *upb_def_file(const upb_def *d) { return d->file; }
+
 upb_def *upb_def_dup(const upb_def *def, const void *o) {
   switch (def->type) {
     case UPB_DEF_MSG:
@@ -102,11 +143,12 @@ static bool upb_def_init(upb_def *def, upb_deftype_t type,
   def->type = type;
   def->fullname = NULL;
   def->came_from_user = false;
+  def->file = NULL;
   return true;
 }
 
 static void upb_def_uninit(upb_def *def) {
-  free((void*)def->fullname);
+  upb_gfree((void*)def->fullname);
 }
 
 static const char *msgdef_name(const upb_msgdef *m) {
@@ -243,8 +285,19 @@ static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
   int i;
   uint32_t selector;
   int n = upb_msgdef_numfields(m);
-  upb_fielddef **fields = malloc(n * sizeof(*fields));
-  if (!fields) return false;
+  upb_fielddef **fields;
+
+  if (n == 0) {
+    m->selector_count = UPB_STATIC_SELECTOR_COUNT;
+    m->submsg_field_count = 0;
+    return true;
+  }
+
+  fields = upb_gmalloc(n * sizeof(*fields));
+  if (!fields) {
+    upb_upberr_setoom(s);
+    return false;
+  }
 
   m->submsg_field_count = 0;
   for(i = 0, upb_msg_field_begin(&j, m);
@@ -253,7 +306,7 @@ static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
     upb_fielddef *f = upb_msg_iter_field(&j);
     assert(f->msg.def == m);
     if (!upb_validate_field(f, s)) {
-      free(fields);
+      upb_gfree(fields);
       return false;
     }
     if (upb_fielddef_issubmsg(f)) {
@@ -313,15 +366,12 @@ static bool assign_msg_indices(upb_msgdef *m, upb_status *s) {
 #undef TRY
 #endif
 
-  free(fields);
+  upb_gfree(fields);
   return true;
 }
 
-bool upb_def_freeze(upb_def *const* defs, int n, upb_status *s) {
-  int i;
-  int maxdepth;
-  bool ret;
-  upb_status_clear(s);
+bool _upb_def_validate(upb_def *const*defs, size_t n, upb_status *s) {
+  size_t i;
 
   /* First perform validation, in two passes so we can check that we have a
    * transitive closure without needing to search. */
@@ -347,8 +397,9 @@ bool upb_def_freeze(upb_def *const* defs, int n, upb_status *s) {
   /* Second pass of validation.  Also assign selector bases and indexes, and
    * compact tables. */
   for (i = 0; i < n; i++) {
-    upb_msgdef *m = upb_dyncast_msgdef_mutable(defs[i]);
-    upb_enumdef *e = upb_dyncast_enumdef_mutable(defs[i]);
+    upb_def *def = defs[i];
+    upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
+    upb_enumdef *e = upb_dyncast_enumdef_mutable(def);
     if (m) {
       upb_inttable_compact(&m->itof);
       if (!assign_msg_indices(m, s)) {
@@ -359,23 +410,31 @@ bool upb_def_freeze(upb_def *const* defs, int n, upb_status *s) {
     }
   }
 
-  /* Def graph contains FieldDefs between each MessageDef, so double the
-   * limit. */
-  maxdepth = UPB_MAX_MESSAGE_DEPTH * 2;
-
-  /* Validation all passed; freeze the defs. */
-  ret = upb_refcounted_freeze((upb_refcounted * const *)defs, n, s, maxdepth);
-  assert(!(s && ret != upb_ok(s)));
-  return ret;
+  return true;
 
 err:
   for (i = 0; i < n; i++) {
-    defs[i]->came_from_user = false;
+    upb_def *def = defs[i];
+    def->came_from_user = false;
   }
   assert(!(s && upb_ok(s)));
   return false;
 }
 
+bool upb_def_freeze(upb_def *const* defs, size_t n, upb_status *s) {
+  /* Def graph contains FieldDefs between each MessageDef, so double the
+   * limit. */
+  const size_t maxdepth = UPB_MAX_MESSAGE_DEPTH * 2;
+
+  if (!_upb_def_validate(defs, n, s)) {
+    return false;
+  }
+
+
+  /* Validation all passed; freeze the objects. */
+  return upb_refcounted_freeze((upb_refcounted *const*)defs, n, s, maxdepth);
+}
+
 
 /* upb_enumdef ****************************************************************/
 
@@ -384,21 +443,26 @@ static void upb_enumdef_free(upb_refcounted *r) {
   upb_inttable_iter i;
   upb_inttable_begin(&i, &e->iton);
   for( ; !upb_inttable_done(&i); upb_inttable_next(&i)) {
-    /* To clean up the upb_strdup() from upb_enumdef_addval(). */
-    free(upb_value_getcstr(upb_inttable_iter_value(&i)));
+    /* To clean up the upb_gstrdup() from upb_enumdef_addval(). */
+    upb_gfree(upb_value_getcstr(upb_inttable_iter_value(&i)));
   }
   upb_strtable_uninit(&e->ntoi);
   upb_inttable_uninit(&e->iton);
   upb_def_uninit(upb_enumdef_upcast_mutable(e));
-  free(e);
+  upb_gfree(e);
 }
 
+const struct upb_refcounted_vtbl upb_enumdef_vtbl = {NULL, &upb_enumdef_free};
+
 upb_enumdef *upb_enumdef_new(const void *owner) {
-  static const struct upb_refcounted_vtbl vtbl = {NULL, &upb_enumdef_free};
-  upb_enumdef *e = malloc(sizeof(*e));
+  upb_enumdef *e = upb_gmalloc(sizeof(*e));
   if (!e) return NULL;
-  if (!upb_def_init(upb_enumdef_upcast_mutable(e), UPB_DEF_ENUM, &vtbl, owner))
+
+  if (!upb_def_init(upb_enumdef_upcast_mutable(e), UPB_DEF_ENUM,
+                    &upb_enumdef_vtbl, owner)) {
     goto err2;
+  }
+
   if (!upb_strtable_init(&e->ntoi, UPB_CTYPE_INT32)) goto err2;
   if (!upb_inttable_init(&e->iton, UPB_CTYPE_CSTR)) goto err1;
   return e;
@@ -406,7 +470,7 @@ upb_enumdef *upb_enumdef_new(const void *owner) {
 err1:
   upb_strtable_uninit(&e->ntoi);
 err2:
-  free(e);
+  upb_gfree(e);
   return NULL;
 }
 
@@ -434,6 +498,10 @@ const char *upb_enumdef_fullname(const upb_enumdef *e) {
   return upb_def_fullname(upb_enumdef_upcast(e));
 }
 
+const char *upb_enumdef_name(const upb_enumdef *e) {
+  return upb_def_name(upb_enumdef_upcast(e));
+}
+
 bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
                              upb_status *s) {
   return upb_def_setfullname(upb_enumdef_upcast_mutable(e), fullname, s);
@@ -441,27 +509,36 @@ bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
 
 bool upb_enumdef_addval(upb_enumdef *e, const char *name, int32_t num,
                         upb_status *status) {
+  char *name2;
+
   if (!upb_isident(name, strlen(name), false, status)) {
     return false;
   }
+
   if (upb_enumdef_ntoiz(e, name, NULL)) {
     upb_status_seterrf(status, "name '%s' is already defined", name);
     return false;
   }
+
   if (!upb_strtable_insert(&e->ntoi, name, upb_value_int32(num))) {
     upb_status_seterrmsg(status, "out of memory");
     return false;
   }
-  if (!upb_inttable_lookup(&e->iton, num, NULL) &&
-      !upb_inttable_insert(&e->iton, num, upb_value_cstr(upb_strdup(name)))) {
-    upb_status_seterrmsg(status, "out of memory");
-    upb_strtable_remove(&e->ntoi, name, NULL);
-    return false;
+
+  if (!upb_inttable_lookup(&e->iton, num, NULL)) {
+    name2 = upb_gstrdup(name);
+    if (!name2 || !upb_inttable_insert(&e->iton, num, upb_value_cstr(name2))) {
+      upb_status_seterrmsg(status, "out of memory");
+      upb_strtable_remove(&e->ntoi, name, NULL);
+      return false;
+    }
   }
+
   if (upb_enumdef_numvals(e) == 1) {
     bool ok = upb_enumdef_setdefault(e, num, NULL);
     UPB_ASSERT_VAR(ok, ok);
   }
+
   return true;
 }
 
@@ -537,7 +614,7 @@ static void visitfield(const upb_refcounted *r, upb_refcounted_visit *visit,
     visit(r, upb_msgdef_upcast2(upb_fielddef_containingtype(f)), closure);
   }
   if (upb_fielddef_containingoneof(f)) {
-    visit(r, upb_oneofdef_upcast2(upb_fielddef_containingoneof(f)), closure);
+    visit(r, upb_oneofdef_upcast(upb_fielddef_containingoneof(f)), closure);
   }
   if (upb_fielddef_subdef(f)) {
     visit(r, upb_def_upcast(upb_fielddef_subdef(f)), closure);
@@ -548,9 +625,9 @@ static void freefield(upb_refcounted *r) {
   upb_fielddef *f = (upb_fielddef*)r;
   upb_fielddef_uninit_default(f);
   if (f->subdef_is_symbolic)
-    free(f->sub.name);
+    upb_gfree(f->sub.name);
   upb_def_uninit(upb_fielddef_upcast_mutable(f));
-  free(f);
+  upb_gfree(f);
 }
 
 static const char *enumdefaultstr(const upb_fielddef *f) {
@@ -606,12 +683,14 @@ static bool enumdefaultint32(const upb_fielddef *f, int32_t *val) {
   return false;
 }
 
+const struct upb_refcounted_vtbl upb_fielddef_vtbl = {visitfield, freefield};
+
 upb_fielddef *upb_fielddef_new(const void *o) {
-  static const struct upb_refcounted_vtbl vtbl = {visitfield, freefield};
-  upb_fielddef *f = malloc(sizeof(*f));
+  upb_fielddef *f = upb_gmalloc(sizeof(*f));
   if (!f) return NULL;
-  if (!upb_def_init(upb_fielddef_upcast_mutable(f), UPB_DEF_FIELD, &vtbl, o)) {
-    free(f);
+  if (!upb_def_init(upb_fielddef_upcast_mutable(f), UPB_DEF_FIELD,
+                    &upb_fielddef_vtbl, o)) {
+    upb_gfree(f);
     return NULL;
   }
   f->msg.def = NULL;
@@ -662,7 +741,7 @@ upb_fielddef *upb_fielddef_dup(const upb_fielddef *f, const void *owner) {
     srcname = f->sub.def ? upb_def_fullname(f->sub.def) : NULL;
   }
   if (srcname) {
-    char *newname = malloc(strlen(f->sub.def->fullname) + 2);
+    char *newname = upb_gmalloc(strlen(f->sub.def->fullname) + 2);
     if (!newname) {
       upb_fielddef_unref(newf, owner);
       return NULL;
@@ -670,7 +749,7 @@ upb_fielddef *upb_fielddef_dup(const upb_fielddef *f, const void *owner) {
     strcpy(newname, ".");
     strcat(newname, f->sub.def->fullname);
     upb_fielddef_setsubdefname(newf, newname, NULL);
-    free(newname);
+    upb_gfree(newname);
   }
 
   return newf;
@@ -777,11 +856,12 @@ const char *upb_fielddef_containingtypename(upb_fielddef *f) {
 }
 
 static void release_containingtype(upb_fielddef *f) {
-  if (f->msg_is_symbolic) free(f->msg.name);
+  if (f->msg_is_symbolic) upb_gfree(f->msg.name);
 }
 
 bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
                                         upb_status *s) {
+  char *name_copy;
   assert(!upb_fielddef_isfrozen(f));
   if (upb_fielddef_containingtype(f)) {
     upb_status_seterrmsg(s, "field has already been added to a message.");
@@ -789,8 +869,15 @@ bool upb_fielddef_setcontainingtypename(upb_fielddef *f, const char *name,
   }
   /* TODO: validate name (upb_isident() doesn't quite work atm because this name
    * may have a leading "."). */
+
+  name_copy = upb_gstrdup(name);
+  if (!name_copy) {
+    upb_upberr_setoom(s);
+    return false;
+  }
+
   release_containingtype(f);
-  f->msg.name = upb_strdup(name);
+  f->msg.name = name_copy;
   f->msg_is_symbolic = true;
   return true;
 }
@@ -1191,7 +1278,7 @@ static bool upb_subdef_typecheck(upb_fielddef *f, const upb_def *subdef,
 
 static void release_subdef(upb_fielddef *f) {
   if (f->subdef_is_symbolic) {
-    free(f->sub.name);
+    upb_gfree(f->sub.name);
   } else if (f->sub.def) {
     upb_unref2(f->sub.def, f);
   }
@@ -1221,15 +1308,23 @@ bool upb_fielddef_setenumsubdef(upb_fielddef *f, const upb_enumdef *subdef,
 
 bool upb_fielddef_setsubdefname(upb_fielddef *f, const char *name,
                                 upb_status *s) {
+  char *name_copy;
   assert(!upb_fielddef_isfrozen(f));
   if (!upb_fielddef_hassubdef(f)) {
     upb_status_seterrmsg(s, "field type does not accept a subdef");
     return false;
   }
+
+  name_copy = upb_gstrdup(name);
+  if (!name_copy) {
+    upb_upberr_setoom(s);
+    return false;
+  }
+
   /* TODO: validate name (upb_isident() doesn't quite work atm because this name
    * may have a leading "."). */
   release_subdef(f);
-  f->sub.name = upb_strdup(name);
+  f->sub.name = name_copy;
   f->subdef_is_symbolic = true;
   return true;
 }
@@ -1263,7 +1358,7 @@ bool upb_fielddef_haspresence(const upb_fielddef *f) {
   /* Primitive field: return true unless there is a message that specifies
    * presence should not exist. */
   if (f->msg_is_symbolic || !f->msg.def) return true;
-  return f->msg.def->primitives_have_presence;
+  return f->msg.def->syntax == UPB_SYNTAX_PROTO2;
 }
 
 bool upb_fielddef_hassubdef(const upb_fielddef *f) {
@@ -1299,38 +1394,39 @@ static void visitmsg(const upb_refcounted *r, upb_refcounted_visit *visit,
       !upb_msg_oneof_done(&o);
       upb_msg_oneof_next(&o)) {
     upb_oneofdef *f = upb_msg_iter_oneof(&o);
-    visit(r, upb_oneofdef_upcast2(f), closure);
+    visit(r, upb_oneofdef_upcast(f), closure);
   }
 }
 
 static void freemsg(upb_refcounted *r) {
   upb_msgdef *m = (upb_msgdef*)r;
-  upb_strtable_uninit(&m->ntoo);
   upb_strtable_uninit(&m->ntof);
   upb_inttable_uninit(&m->itof);
   upb_def_uninit(upb_msgdef_upcast_mutable(m));
-  free(m);
+  upb_gfree(m);
 }
 
+const struct upb_refcounted_vtbl upb_msgdef_vtbl = {visitmsg, freemsg};
+
 upb_msgdef *upb_msgdef_new(const void *owner) {
-  static const struct upb_refcounted_vtbl vtbl = {visitmsg, freemsg};
-  upb_msgdef *m = malloc(sizeof(*m));
+  upb_msgdef *m = upb_gmalloc(sizeof(*m));
   if (!m) return NULL;
-  if (!upb_def_init(upb_msgdef_upcast_mutable(m), UPB_DEF_MSG, &vtbl, owner))
+
+  if (!upb_def_init(upb_msgdef_upcast_mutable(m), UPB_DEF_MSG, &upb_msgdef_vtbl,
+                    owner)) {
     goto err2;
-  if (!upb_inttable_init(&m->itof, UPB_CTYPE_PTR)) goto err3;
-  if (!upb_strtable_init(&m->ntof, UPB_CTYPE_PTR)) goto err2;
-  if (!upb_strtable_init(&m->ntoo, UPB_CTYPE_PTR)) goto err1;
+  }
+
+  if (!upb_inttable_init(&m->itof, UPB_CTYPE_PTR)) goto err2;
+  if (!upb_strtable_init(&m->ntof, UPB_CTYPE_PTR)) goto err1;
   m->map_entry = false;
-  m->primitives_have_presence = true;
+  m->syntax = UPB_SYNTAX_PROTO2;
   return m;
 
 err1:
-  upb_strtable_uninit(&m->ntof);
-err2:
   upb_inttable_uninit(&m->itof);
-err3:
-  free(m);
+err2:
+  upb_gfree(m);
   return NULL;
 }
 
@@ -1345,7 +1441,7 @@ upb_msgdef *upb_msgdef_dup(const upb_msgdef *m, const void *owner) {
                            upb_def_fullname(upb_msgdef_upcast(m)),
                            NULL);
   newm->map_entry = m->map_entry;
-  newm->primitives_have_presence = m->primitives_have_presence;
+  newm->syntax = m->syntax;
   UPB_ASSERT_VAR(ok, ok);
   for(upb_msg_field_begin(&i, m);
       !upb_msg_field_done(&i);
@@ -1379,11 +1475,28 @@ const char *upb_msgdef_fullname(const upb_msgdef *m) {
   return upb_def_fullname(upb_msgdef_upcast(m));
 }
 
+const char *upb_msgdef_name(const upb_msgdef *m) {
+  return upb_def_name(upb_msgdef_upcast(m));
+}
+
 bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname,
                             upb_status *s) {
   return upb_def_setfullname(upb_msgdef_upcast_mutable(m), fullname, s);
 }
 
+bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax) {
+  if (syntax != UPB_SYNTAX_PROTO2 && syntax != UPB_SYNTAX_PROTO3) {
+    return false;
+  }
+
+  m->syntax = syntax;
+  return true;
+}
+
+upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m) {
+  return m->syntax;
+}
+
 /* Helper: check that the field |f| is safe to add to msgdef |m|. Set an error
  * on status |s| and return false if not. */
 static bool check_field_add(const upb_msgdef *m, const upb_fielddef *f,
@@ -1394,9 +1507,11 @@ static bool check_field_add(const upb_msgdef *m, const upb_fielddef *f,
   } else if (upb_fielddef_name(f) == NULL || upb_fielddef_number(f) == 0) {
     upb_status_seterrmsg(s, "field name or number were not set");
     return false;
-  } else if (upb_msgdef_ntofz(m, upb_fielddef_name(f)) ||
-             upb_msgdef_itof(m, upb_fielddef_number(f))) {
-    upb_status_seterrmsg(s, "duplicate field name or number for field");
+  } else if (upb_msgdef_itof(m, upb_fielddef_number(f))) {
+    upb_status_seterrmsg(s, "duplicate field number");
+    return false;
+  } else if (upb_strtable_lookup(&m->ntof, upb_fielddef_name(f), NULL)) {
+    upb_status_seterrmsg(s, "name conflicts with existing field or oneof");
     return false;
   }
   return true;
@@ -1457,8 +1572,8 @@ bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
   } else if (upb_oneofdef_name(o) == NULL) {
     upb_status_seterrmsg(s, "oneofdef name was not set");
     return false;
-  } else if (upb_msgdef_ntooz(m, upb_oneofdef_name(o))) {
-    upb_status_seterrmsg(s, "duplicate oneof name");
+  } else if (upb_strtable_lookup(&m->ntof, upb_oneofdef_name(o), NULL)) {
+    upb_status_seterrmsg(s, "name conflicts with existing field or oneof");
     return false;
   }
 
@@ -1475,7 +1590,7 @@ bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
 
   /* Add oneof itself first. */
   o->parent = m;
-  upb_strtable_insert(&m->ntoo, upb_oneofdef_name(o), upb_value_ptr(o));
+  upb_strtable_insert(&m->ntof, upb_oneofdef_name(o), upb_value_ptr(o));
   upb_ref2(o, m);
   upb_ref2(m, o);
 
@@ -1490,11 +1605,6 @@ bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
   return true;
 }
 
-void upb_msgdef_setprimitiveshavepresence(upb_msgdef *m, bool have_presence) {
-  assert(!upb_msgdef_isfrozen(m));
-  m->primitives_have_presence = have_presence;
-}
-
 const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i) {
   upb_value val;
   return upb_inttable_lookup32(&m->itof, i, &val) ?
@@ -1504,23 +1614,47 @@ const upb_fielddef *upb_msgdef_itof(const upb_msgdef *m, uint32_t i) {
 const upb_fielddef *upb_msgdef_ntof(const upb_msgdef *m, const char *name,
                                     size_t len) {
   upb_value val;
-  return upb_strtable_lookup2(&m->ntof, name, len, &val) ?
-      upb_value_getptr(val) : NULL;
+
+  if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
+    return NULL;
+  }
+
+  return upb_trygetfield(upb_value_getptr(val));
 }
 
 const upb_oneofdef *upb_msgdef_ntoo(const upb_msgdef *m, const char *name,
                                     size_t len) {
   upb_value val;
-  return upb_strtable_lookup2(&m->ntoo, name, len, &val) ?
-      upb_value_getptr(val) : NULL;
+
+  if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
+    return NULL;
+  }
+
+  return upb_trygetoneof(upb_value_getptr(val));
+}
+
+bool upb_msgdef_lookupname(const upb_msgdef *m, const char *name, size_t len,
+                           const upb_fielddef **f, const upb_oneofdef **o) {
+  upb_value val;
+
+  if (!upb_strtable_lookup2(&m->ntof, name, len, &val)) {
+    return false;
+  }
+
+  *o = upb_trygetoneof(upb_value_getptr(val));
+  *f = upb_trygetfield(upb_value_getptr(val));
+  assert((*o != NULL) ^ (*f != NULL));  /* Exactly one of the two should be set. */
+  return true;
 }
 
 int upb_msgdef_numfields(const upb_msgdef *m) {
-  return upb_strtable_count(&m->ntof);
+  /* The number table contains only fields. */
+  return upb_inttable_count(&m->itof);
 }
 
 int upb_msgdef_numoneofs(const upb_msgdef *m) {
-  return upb_strtable_count(&m->ntoo);
+  /* The name table includes oneofs, and the number table does not. */
+  return upb_strtable_count(&m->ntof) - upb_inttable_count(&m->itof);
 }
 
 void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry) {
@@ -1551,10 +1685,21 @@ void upb_msg_field_iter_setdone(upb_msg_field_iter *iter) {
 }
 
 void upb_msg_oneof_begin(upb_msg_oneof_iter *iter, const upb_msgdef *m) {
-  upb_strtable_begin(iter, &m->ntoo);
+  upb_strtable_begin(iter, &m->ntof);
+  /* We need to skip past any initial fields. */
+  while (!upb_strtable_done(iter) &&
+         !upb_isoneof(upb_value_getptr(upb_strtable_iter_value(iter)))) {
+    upb_strtable_next(iter);
+  }
 }
 
-void upb_msg_oneof_next(upb_msg_oneof_iter *iter) { upb_strtable_next(iter); }
+void upb_msg_oneof_next(upb_msg_oneof_iter *iter) {
+  /* We need to skip past fields to return only oneofs. */
+  do {
+    upb_strtable_next(iter);
+  } while (!upb_strtable_done(iter) &&
+           !upb_isoneof(upb_value_getptr(upb_strtable_iter_value(iter))));
+}
 
 bool upb_msg_oneof_done(const upb_msg_oneof_iter *iter) {
   return upb_strtable_done(iter);
@@ -1587,26 +1732,36 @@ static void freeoneof(upb_refcounted *r) {
   upb_oneofdef *o = (upb_oneofdef*)r;
   upb_strtable_uninit(&o->ntof);
   upb_inttable_uninit(&o->itof);
-  upb_def_uninit(upb_oneofdef_upcast_mutable(o));
-  free(o);
+  upb_gfree((void*)o->name);
+  upb_gfree(o);
 }
 
+const struct upb_refcounted_vtbl upb_oneofdef_vtbl = {visitoneof, freeoneof};
+
 upb_oneofdef *upb_oneofdef_new(const void *owner) {
-  static const struct upb_refcounted_vtbl vtbl = {visitoneof, freeoneof};
-  upb_oneofdef *o = malloc(sizeof(*o));
+  upb_oneofdef *o = upb_gmalloc(sizeof(*o));
+
+  if (!o) {
+    return NULL;
+  }
+
   o->parent = NULL;
-  if (!o) return NULL;
-  if (!upb_def_init(upb_oneofdef_upcast_mutable(o), UPB_DEF_ONEOF, &vtbl,
-                    owner))
+  o->name = NULL;
+
+  if (!upb_refcounted_init(upb_oneofdef_upcast_mutable(o), &upb_oneofdef_vtbl,
+                           owner)) {
     goto err2;
+  }
+
   if (!upb_inttable_init(&o->itof, UPB_CTYPE_PTR)) goto err2;
   if (!upb_strtable_init(&o->ntof, UPB_CTYPE_PTR)) goto err1;
+
   return o;
 
 err1:
   upb_inttable_uninit(&o->itof);
 err2:
-  free(o);
+  upb_gfree(o);
   return NULL;
 }
 
@@ -1615,8 +1770,7 @@ upb_oneofdef *upb_oneofdef_dup(const upb_oneofdef *o, const void *owner) {
   upb_oneof_iter i;
   upb_oneofdef *newo = upb_oneofdef_new(owner);
   if (!newo) return NULL;
-  ok = upb_def_setfullname(upb_oneofdef_upcast_mutable(newo),
-                           upb_def_fullname(upb_oneofdef_upcast(o)), NULL);
+  ok = upb_oneofdef_setname(newo, upb_oneofdef_name(o), NULL);
   UPB_ASSERT_VAR(ok, ok);
   for (upb_oneof_begin(&i, o); !upb_oneof_done(&i); upb_oneof_next(&i)) {
     upb_fielddef *f = upb_fielddef_dup(upb_oneof_iter_field(&i), &f);
@@ -1628,17 +1782,28 @@ upb_oneofdef *upb_oneofdef_dup(const upb_oneofdef *o, const void *owner) {
   return newo;
 }
 
-const char *upb_oneofdef_name(const upb_oneofdef *o) {
-  return upb_def_fullname(upb_oneofdef_upcast(o));
-}
+const char *upb_oneofdef_name(const upb_oneofdef *o) { return o->name; }
 
-bool upb_oneofdef_setname(upb_oneofdef *o, const char *fullname,
-                             upb_status *s) {
+bool upb_oneofdef_setname(upb_oneofdef *o, const char *name, upb_status *s) {
+  assert(!upb_oneofdef_isfrozen(o));
   if (upb_oneofdef_containingtype(o)) {
     upb_status_seterrmsg(s, "oneof already added to a message");
     return false;
   }
-  return upb_def_setfullname(upb_oneofdef_upcast_mutable(o), fullname, s);
+
+  if (!upb_isident(name, strlen(name), true, s)) {
+    return false;
+  }
+
+  name = upb_gstrdup(name);
+  if (!name) {
+    upb_status_seterrmsg(s, "One of memory");
+    return false;
+  }
+
+  upb_gfree((void*)o->name);
+  o->name = name;
+  return true;
 }
 
 const upb_msgdef *upb_oneofdef_containingtype(const upb_oneofdef *o) {
@@ -1757,276 +1922,191 @@ void upb_oneof_iter_setdone(upb_oneof_iter *iter) {
   upb_inttable_iter_setdone(iter);
 }
 
+/* upb_filedef ****************************************************************/
 
-#include <stdlib.h>
-#include <stdio.h>
-#include <string.h>
-
-typedef struct cleanup_ent {
-  upb_cleanup_func *cleanup;
-  void *ud;
-  struct cleanup_ent *next;
-} cleanup_ent;
-
-static void *seeded_alloc(void *ud, void *ptr, size_t oldsize, size_t size);
-
-/* Default allocator **********************************************************/
-
-/* Just use realloc, keeping all allocated blocks in a linked list to destroy at
- * the end. */
-
-typedef struct mem_block {
-  /* List is doubly-linked, because in cases where realloc() moves an existing
-   * block, we need to be able to remove the old pointer from the list
-   * efficiently. */
-  struct mem_block *prev, *next;
-#ifndef NDEBUG
-  size_t size;  /* Doesn't include mem_block structure. */
-#endif
-} mem_block;
-
-typedef struct {
-  mem_block *head;
-} default_alloc_ud;
-
-static void *default_alloc(void *_ud, void *ptr, size_t oldsize, size_t size) {
-  default_alloc_ud *ud = _ud;
-  mem_block *from, *block;
-  void *ret;
-  UPB_UNUSED(oldsize);
-
-  from = ptr ? (void*)((char*)ptr - sizeof(mem_block)) : NULL;
-
-#ifndef NDEBUG
-  if (from) {
-    assert(oldsize <= from->size);
-  }
-#endif
-
-  /* TODO(haberman): we probably need to provide even better alignment here,
-   * like 16-byte alignment of the returned data pointer. */
-  block = realloc(from, size + sizeof(mem_block));
-  if (!block) return NULL;
-  ret = (char*)block + sizeof(*block);
-
-#ifndef NDEBUG
-  block->size = size;
-#endif
+static void visitfiledef(const upb_refcounted *r, upb_refcounted_visit *visit,
+                         void *closure) {
+  const upb_filedef *f = (const upb_filedef*)r;
+  size_t i;
 
-  if (from) {
-    if (block != from) {
-      /* The block was moved, so pointers in next and prev blocks must be
-       * updated to its new location. */
-      if (block->next) block->next->prev = block;
-      if (block->prev) block->prev->next = block;
-      if (ud->head == from) ud->head = block;
-    }
-  } else {
-    /* Insert at head of linked list. */
-    block->prev = NULL;
-    block->next = ud->head;
-    if (block->next) block->next->prev = block;
-    ud->head = block;
+  for(i = 0; i < upb_filedef_defcount(f); i++) {
+    visit(r, upb_def_upcast(upb_filedef_def(f, i)), closure);
   }
-
-  return ret;
 }
 
-static void default_alloc_cleanup(void *_ud) {
-  default_alloc_ud *ud = _ud;
-  mem_block *block = ud->head;
+static void freefiledef(upb_refcounted *r) {
+  upb_filedef *f = (upb_filedef*)r;
+  size_t i;
 
-  while (block) {
-    void *to_free = block;
-    block = block->next;
-    free(to_free);
+  for(i = 0; i < upb_filedef_depcount(f); i++) {
+    upb_filedef_unref(upb_filedef_dep(f, i), f);
   }
-}
 
+  upb_inttable_uninit(&f->defs);
+  upb_inttable_uninit(&f->deps);
+  upb_gfree((void*)f->name);
+  upb_gfree((void*)f->package);
+  upb_gfree(f);
+}
 
-/* Standard error functions ***************************************************/
+const struct upb_refcounted_vtbl upb_filedef_vtbl = {visitfiledef, freefiledef};
 
-static bool default_err(void *ud, const upb_status *status) {
-  UPB_UNUSED(ud);
-  UPB_UNUSED(status);
-  return false;
-}
+upb_filedef *upb_filedef_new(const void *owner) {
+  upb_filedef *f = upb_gmalloc(sizeof(*f));
 
-static bool write_err_to(void *ud, const upb_status *status) {
-  upb_status *copy_to = ud;
-  upb_status_copy(copy_to, status);
-  return false;
-}
+  if (!f) {
+    return NULL;
+  }
 
+  f->package = NULL;
+  f->name = NULL;
+  f->syntax = UPB_SYNTAX_PROTO2;
 
-/* upb_env ********************************************************************/
+  if (!upb_refcounted_init(upb_filedef_upcast_mutable(f), &upb_filedef_vtbl,
+                           owner)) {
+    goto err;
+  }
 
-void upb_env_init(upb_env *e) {
-  default_alloc_ud *ud = (default_alloc_ud*)&e->default_alloc_ud;
-  e->ok_ = true;
-  e->bytes_allocated = 0;
-  e->cleanup_head = NULL;
+  if (!upb_inttable_init(&f->defs, UPB_CTYPE_CONSTPTR)) {
+    goto err;
+  }
 
-  ud->head = NULL;
+  if (!upb_inttable_init(&f->deps, UPB_CTYPE_CONSTPTR)) {
+    goto err2;
+  }
 
-  /* Set default functions. */
-  upb_env_setallocfunc(e, default_alloc, ud);
-  upb_env_seterrorfunc(e, default_err, NULL);
-}
+  return f;
 
-void upb_env_uninit(upb_env *e) {
-  cleanup_ent *ent = e->cleanup_head;
 
-  while (ent) {
-    ent->cleanup(ent->ud);
-    ent = ent->next;
-  }
+err2:
+  upb_inttable_uninit(&f->defs);
 
-  /* Must do this after running cleanup functions, because this will delete
-     the memory we store our cleanup entries in! */
-  if (e->alloc == default_alloc) {
-    default_alloc_cleanup(e->alloc_ud);
-  }
+err:
+  upb_gfree(f);
+  return NULL;
 }
 
-UPB_FORCEINLINE void upb_env_setallocfunc(upb_env *e, upb_alloc_func *alloc,
-                                          void *ud) {
-  e->alloc = alloc;
-  e->alloc_ud = ud;
+const char *upb_filedef_name(const upb_filedef *f) {
+  return f->name;
 }
 
-UPB_FORCEINLINE void upb_env_seterrorfunc(upb_env *e, upb_error_func *func,
-                                          void *ud) {
-  e->err = func;
-  e->err_ud = ud;
+const char *upb_filedef_package(const upb_filedef *f) {
+  return f->package;
 }
 
-void upb_env_reporterrorsto(upb_env *e, upb_status *status) {
-  e->err = write_err_to;
-  e->err_ud = status;
+upb_syntax_t upb_filedef_syntax(const upb_filedef *f) {
+  return f->syntax;
 }
 
-bool upb_env_ok(const upb_env *e) {
-  return e->ok_;
+size_t upb_filedef_defcount(const upb_filedef *f) {
+  return upb_inttable_count(&f->defs);
 }
 
-bool upb_env_reporterror(upb_env *e, const upb_status *status) {
-  e->ok_ = false;
-  return e->err(e->err_ud, status);
+size_t upb_filedef_depcount(const upb_filedef *f) {
+  return upb_inttable_count(&f->deps);
 }
 
-bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud) {
-  cleanup_ent *ent = upb_env_malloc(e, sizeof(cleanup_ent));
-  if (!ent) return false;
-
-  ent->cleanup = func;
-  ent->ud = ud;
-  ent->next = e->cleanup_head;
-  e->cleanup_head = ent;
-
-  return true;
-}
+const upb_def *upb_filedef_def(const upb_filedef *f, size_t i) {
+  upb_value v;
 
-void *upb_env_malloc(upb_env *e, size_t size) {
-  e->bytes_allocated += size;
-  if (e->alloc == seeded_alloc) {
-    /* This is equivalent to the next branch, but allows inlining for a
-     * measurable perf benefit. */
-    return seeded_alloc(e->alloc_ud, NULL, 0, size);
+  if (upb_inttable_lookup32(&f->defs, i, &v)) {
+    return upb_value_getconstptr(v);
   } else {
-    return e->alloc(e->alloc_ud, NULL, 0, size);
+    return NULL;
   }
 }
 
-void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size) {
-  char *ret;
-  assert(oldsize <= size);
-  ret = e->alloc(e->alloc_ud, ptr, oldsize, size);
-
-#ifndef NDEBUG
-  /* Overwrite non-preserved memory to ensure callers are passing the oldsize
-   * that they truly require. */
-  memset(ret + oldsize, 0xff, size - oldsize);
-#endif
+const upb_filedef *upb_filedef_dep(const upb_filedef *f, size_t i) {
+  upb_value v;
 
-  return ret;
+  if (upb_inttable_lookup32(&f->deps, i, &v)) {
+    return upb_value_getconstptr(v);
+  } else {
+    return NULL;
+  }
 }
 
-size_t upb_env_bytesallocated(const upb_env *e) {
-  return e->bytes_allocated;
+bool upb_filedef_setname(upb_filedef *f, const char *name, upb_status *s) {
+  name = upb_gstrdup(name);
+  if (!name) {
+    upb_upberr_setoom(s);
+    return false;
+  }
+  upb_gfree((void*)f->name);
+  f->name = name;
+  return true;
 }
 
-
-/* upb_seededalloc ************************************************************/
-
-/* Be conservative and choose 16 in case anyone is using SSE. */
-static const size_t maxalign = 16;
-
-static size_t align_up(size_t size) {
-  return ((size + maxalign - 1) / maxalign) * maxalign;
+bool upb_filedef_setpackage(upb_filedef *f, const char *package,
+                            upb_status *s) {
+  if (!upb_isident(package, strlen(package), true, s)) return false;
+  package = upb_gstrdup(package);
+  if (!package) {
+    upb_upberr_setoom(s);
+    return false;
+  }
+  upb_gfree((void*)f->package);
+  f->package = package;
+  return true;
 }
 
-UPB_FORCEINLINE static void *seeded_alloc(void *ud, void *ptr, size_t oldsize,
-                                          size_t size) {
-  upb_seededalloc *a = ud;
-
-  size = align_up(size);
-
-  assert(a->mem_limit >= a->mem_ptr);
+bool upb_filedef_setsyntax(upb_filedef *f, upb_syntax_t syntax,
+                           upb_status *s) {
+  UPB_UNUSED(s);
+  if (syntax != UPB_SYNTAX_PROTO2 &&
+      syntax != UPB_SYNTAX_PROTO3) {
+    upb_status_seterrmsg(s, "Unknown syntax value.");
+    return false;
+  }
+  f->syntax = syntax;
 
-  if (oldsize == 0 && size <= (size_t)(a->mem_limit - a->mem_ptr)) {
-    /* Fast path: we can satisfy from the initial allocation. */
-    void *ret = a->mem_ptr;
-    a->mem_ptr += size;
-    return ret;
-  } else {
-    char *chptr = ptr;
-    /* Slow path: fallback to other allocator. */
-    a->need_cleanup = true;
-    /* Is `ptr` part of the user-provided initial block? Don't pass it to the
-     * default allocator if so; otherwise, it may try to realloc() the block. */
-    if (chptr >= a->mem_base && chptr < a->mem_limit) {
-      void *ret;
-      assert(chptr + oldsize <= a->mem_limit);
-      ret = a->alloc(a->alloc_ud, NULL, 0, size);
-      if (ret) memcpy(ret, ptr, oldsize);
-      return ret;
-    } else {
-      return a->alloc(a->alloc_ud, ptr, oldsize, size);
+  {
+    /* Set all messages in this file to match. */
+    size_t i;
+    for (i = 0; i < upb_filedef_defcount(f); i++) {
+      /* Casting const away is safe since all defs in mutable filedef must
+       * also be mutable. */
+      upb_def *def = (upb_def*)upb_filedef_def(f, i);
+
+      upb_msgdef *m = upb_dyncast_msgdef_mutable(def);
+      if (m) {
+        m->syntax = syntax;
+      }
     }
   }
-}
-
-void upb_seededalloc_init(upb_seededalloc *a, void *mem, size_t len) {
-  default_alloc_ud *ud = (default_alloc_ud*)&a->default_alloc_ud;
-  a->mem_base = mem;
-  a->mem_ptr = mem;
-  a->mem_limit = (char*)mem + len;
-  a->need_cleanup = false;
-  a->returned_allocfunc = false;
 
-  ud->head = NULL;
-
-  upb_seededalloc_setfallbackalloc(a, default_alloc, ud);
+  return true;
 }
 
-void upb_seededalloc_uninit(upb_seededalloc *a) {
-  if (a->alloc == default_alloc && a->need_cleanup) {
-    default_alloc_cleanup(a->alloc_ud);
+bool upb_filedef_adddef(upb_filedef *f, upb_def *def, const void *ref_donor,
+                        upb_status *s) {
+  if (def->file) {
+    upb_status_seterrmsg(s, "Def is already part of another filedef.");
+    return false;
   }
-}
 
-UPB_FORCEINLINE void upb_seededalloc_setfallbackalloc(upb_seededalloc *a,
-                                                      upb_alloc_func *alloc,
-                                                      void *ud) {
-  assert(!a->returned_allocfunc);
-  a->alloc = alloc;
-  a->alloc_ud = ud;
+  if (upb_inttable_push(&f->defs, upb_value_constptr(def))) {
+    def->file = f;
+    upb_ref2(def, f);
+    if (ref_donor) upb_def_unref(def, ref_donor);
+    if (def->type == UPB_DEF_MSG) {
+      upb_downcast_msgdef_mutable(def)->syntax = f->syntax;
+    }
+    return true;
+  } else {
+    upb_upberr_setoom(s);
+    return false;
+  }
 }
 
-upb_alloc_func *upb_seededalloc_getallocfunc(upb_seededalloc *a) {
-  a->returned_allocfunc = true;
-  return seeded_alloc;
+bool upb_filedef_adddep(upb_filedef *f, const upb_filedef *dep) {
+  if (upb_inttable_push(&f->deps, upb_value_constptr(dep))) {
+    /* Regular ref instead of ref2 because files can't form cycles. */
+    upb_filedef_ref(dep, f);
+    return true;
+  } else {
+    return false;
+  }
 }
 /*
 ** TODO(haberman): it's unclear whether a lot of the consistency checks should
@@ -2034,10 +2114,16 @@ upb_alloc_func *upb_seededalloc_getallocfunc(upb_seededalloc *a) {
 */
 
 
-#include <stdlib.h>
 #include <string.h>
 
 
+static void *upb_calloc(size_t size) {
+  void *mem = upb_gmalloc(size);
+  if (mem) {
+    memset(mem, 0, size);
+  }
+  return mem;
+}
 
 /* Defined for the sole purpose of having a unique pointer value for
  * UPB_NO_CLOSURE. */
@@ -2057,8 +2143,8 @@ static void freehandlers(upb_refcounted *r) {
 
   upb_inttable_uninit(&h->cleanup_);
   upb_msgdef_unref(h->msg, h);
-  free(h->sub);
-  free(h);
+  upb_gfree(h->sub);
+  upb_gfree(h);
 }
 
 static void visithandlers(const upb_refcounted *r, upb_refcounted_visit *visit,
@@ -2308,14 +2394,20 @@ upb_handlers *upb_handlers_new(const upb_msgdef *md, const void *owner) {
   assert(upb_msgdef_isfrozen(md));
 
   extra = sizeof(upb_handlers_tabent) * (md->selector_count - 1);
-  h = calloc(sizeof(*h) + extra, 1);
+  h = upb_calloc(sizeof(*h) + extra);
   if (!h) return NULL;
 
   h->msg = md;
   upb_msgdef_ref(h->msg, h);
   upb_status_clear(&h->status_);
-  h->sub = calloc(md->submsg_field_count, sizeof(*h->sub));
-  if (!h->sub) goto oom;
+
+  if (md->submsg_field_count > 0) {
+    h->sub = upb_calloc(md->submsg_field_count * sizeof(*h->sub));
+    if (!h->sub) goto oom;
+  } else {
+    h->sub = 0;
+  }
+
   if (!upb_refcounted_init(upb_handlers_upcast_mutable(h), &vtbl, owner))
     goto oom;
   if (!upb_inttable_init(&h->cleanup_, UPB_CTYPE_FPTR)) goto oom;
@@ -2730,7 +2822,6 @@ bool upb_byteshandler_setendstr(upb_byteshandler *h,
 
 
 #include <setjmp.h>
-#include <stdlib.h>
 
 static void freeobj(upb_refcounted *o);
 
@@ -2806,8 +2897,31 @@ void upb_unlock();
 /* UPB_DEBUG_REFS mode counts on being able to malloc() memory in some
  * code-paths that can normally never fail, like upb_refcounted_ref().  Since
  * we have no way to propagage out-of-memory errors back to the user, and since
- * these errors can only occur in UPB_DEBUG_REFS mode, we immediately fail. */
-#define CHECK_OOM(predicate) if (!(predicate)) { assert(predicate); exit(1); }
+ * these errors can only occur in UPB_DEBUG_REFS mode, we use an allocator that
+ * immediately aborts on failure (avoiding the global allocator, which might
+ * inject failures). */
+
+#include <stdlib.h>
+
+static void *upb_debugrefs_allocfunc(upb_alloc *alloc, void *ptr,
+                                     size_t oldsize, size_t size) {
+  UPB_UNUSED(alloc);
+  UPB_UNUSED(oldsize);
+  if (size == 0) {
+    free(ptr);
+    return NULL;
+  } else {
+    void *ret = realloc(ptr, size);
+
+    if (!ret) {
+      abort();
+    }
+
+    return ret;
+  }
+}
+
+upb_alloc upb_alloc_debugrefs = {&upb_debugrefs_allocfunc};
 
 typedef struct {
   int count;  /* How many refs there are (duplicates only allowed for ref2). */
@@ -2815,8 +2929,7 @@ typedef struct {
 } trackedref;
 
 static trackedref *trackedref_new(bool is_ref2) {
-  trackedref *ret = malloc(sizeof(*ret));
-  CHECK_OOM(ret);
+  trackedref *ret = upb_malloc(&upb_alloc_debugrefs, sizeof(*ret));
   ret->count = 1;
   ret->is_ref2 = is_ref2;
   return ret;
@@ -2841,15 +2954,15 @@ static void track(const upb_refcounted *r, const void *owner, bool ref2) {
     ref->count++;
   } else {
     trackedref *ref = trackedref_new(ref2);
-    bool ok = upb_inttable_insertptr(r->refs, owner, upb_value_ptr(ref));
-    CHECK_OOM(ok);
+    upb_inttable_insertptr2(r->refs, owner, upb_value_ptr(ref),
+                            &upb_alloc_debugrefs);
     if (ref2) {
       /* We know this cast is safe when it is a ref2, because it's coming from
        * another refcounted object. */
       const upb_refcounted *from = owner;
       assert(!upb_inttable_lookupptr(from->ref2s, r, NULL));
-      ok = upb_inttable_insertptr(from->ref2s, r, upb_value_ptr(NULL));
-      CHECK_OOM(ok);
+      upb_inttable_insertptr2(from->ref2s, r, upb_value_ptr(NULL),
+                              &upb_alloc_debugrefs);
     }
   }
   upb_unlock();
@@ -2907,7 +3020,6 @@ static void getref2s(const upb_refcounted *owner, upb_inttable *tab) {
     upb_value v;
     upb_value count;
     trackedref *ref;
-    bool ok;
     bool found;
 
     upb_refcounted *to = (upb_refcounted*)upb_inttable_iter_key(&i);
@@ -2918,8 +3030,7 @@ static void getref2s(const upb_refcounted *owner, upb_inttable *tab) {
     ref = upb_value_getptr(v);
     count = upb_value_int32(ref->count);
 
-    ok = upb_inttable_insertptr(tab, to, count);
-    CHECK_OOM(ok);
+    upb_inttable_insertptr2(tab, to, count, &upb_alloc_debugrefs);
   }
   upb_unlock();
 }
@@ -2945,21 +3056,19 @@ static void visit_check(const upb_refcounted *obj, const upb_refcounted *subobj,
   assert(removed);
   newcount = upb_value_getint32(v) - 1;
   if (newcount > 0) {
-    upb_inttable_insert(ref2, (uintptr_t)subobj, upb_value_int32(newcount));
+    upb_inttable_insert2(ref2, (uintptr_t)subobj, upb_value_int32(newcount),
+                         &upb_alloc_debugrefs);
   }
 }
 
 static void visit(const upb_refcounted *r, upb_refcounted_visit *v,
                   void *closure) {
-  bool ok;
-
   /* In DEBUG_REFS mode we know what existing ref2 refs there are, so we know
    * exactly the set of nodes that visit() should visit.  So we verify visit()'s
    * correctness here. */
   check_state state;
   state.obj = r;
-  ok = upb_inttable_init(&state.ref2, UPB_CTYPE_INT32);
-  CHECK_OOM(ok);
+  upb_inttable_init2(&state.ref2, UPB_CTYPE_INT32, &upb_alloc_debugrefs);
   getref2s(r, &state.ref2);
 
   /* This should visit any children in the ref2 table. */
@@ -2967,32 +3076,22 @@ static void visit(const upb_refcounted *r, upb_refcounted_visit *v,
 
   /* This assertion will fail if the visit() function missed any children. */
   assert(upb_inttable_count(&state.ref2) == 0);
-  upb_inttable_uninit(&state.ref2);
+  upb_inttable_uninit2(&state.ref2, &upb_alloc_debugrefs);
   if (r->vtbl->visit) r->vtbl->visit(r, v, closure);
 }
 
-static bool trackinit(upb_refcounted *r) {
-  r->refs = malloc(sizeof(*r->refs));
-  r->ref2s = malloc(sizeof(*r->ref2s));
-  if (!r->refs || !r->ref2s) goto err1;
-
-  if (!upb_inttable_init(r->refs, UPB_CTYPE_PTR)) goto err1;
-  if (!upb_inttable_init(r->ref2s, UPB_CTYPE_PTR)) goto err2;
-  return true;
-
-err2:
-  upb_inttable_uninit(r->refs);
-err1:
-  free(r->refs);
-  free(r->ref2s);
-  return false;
+static void trackinit(upb_refcounted *r) {
+  r->refs = upb_malloc(&upb_alloc_debugrefs, sizeof(*r->refs));
+  r->ref2s = upb_malloc(&upb_alloc_debugrefs, sizeof(*r->ref2s));
+  upb_inttable_init2(r->refs, UPB_CTYPE_PTR, &upb_alloc_debugrefs);
+  upb_inttable_init2(r->ref2s, UPB_CTYPE_PTR, &upb_alloc_debugrefs);
 }
 
 static void trackfree(const upb_refcounted *r) {
-  upb_inttable_uninit(r->refs);
-  upb_inttable_uninit(r->ref2s);
-  free(r->refs);
-  free(r->ref2s);
+  upb_inttable_uninit2(r->refs, &upb_alloc_debugrefs);
+  upb_inttable_uninit2(r->ref2s, &upb_alloc_debugrefs);
+  upb_free(&upb_alloc_debugrefs, r->refs);
+  upb_free(&upb_alloc_debugrefs, r->ref2s);
 }
 
 #else
@@ -3015,9 +3114,8 @@ static void checkref(const upb_refcounted *r, const void *owner, bool ref2) {
   UPB_UNUSED(ref2);
 }
 
-static bool trackinit(upb_refcounted *r) {
+static void trackinit(upb_refcounted *r) {
   UPB_UNUSED(r);
-  return true;
 }
 
 static void trackfree(const upb_refcounted *r) {
@@ -3127,12 +3225,12 @@ static upb_refcounted *pop(tarjan *t) {
 }
 
 static void tarjan_newgroup(tarjan *t) {
-  uint32_t *group = malloc(sizeof(*group));
+  uint32_t *group = upb_gmalloc(sizeof(*group));
   if (!group) oom(t);
   /* Push group and empty group leader (we'll fill in leader later). */
   if (!upb_inttable_push(&t->groups, upb_value_ptr(group)) ||
       !upb_inttable_push(&t->groups, upb_value_ptr(NULL))) {
-    free(group);
+    upb_gfree(group);
     oom(t);
   }
   *group = 0;
@@ -3307,7 +3405,7 @@ static bool freeze(upb_refcounted *const*roots, int n, upb_status *s,
       if (obj == move) {
         /* Removing the last object from a group. */
         assert(*obj->group == obj->individual_count);
-        free(obj->group);
+        upb_gfree(obj->group);
       } else {
         obj->next = move->next;
         /* This may decrease to zero; we'll collect GRAY objects (if any) that
@@ -3363,7 +3461,7 @@ static bool freeze(upb_refcounted *const*roots, int n, upb_status *s,
         /* We eagerly free() the group's count (since we can't easily determine
          * the group's remaining size it's the easiest way to ensure it gets
          * done). */
-        free(obj->group);
+        upb_gfree(obj->group);
 
         /* Visit to release ref2's (done in a separate pass since release_ref2
          * depends on o->group being unmodified so it can test merged()). */
@@ -3383,7 +3481,7 @@ err4:
   if (!ret) {
     upb_inttable_begin(&iter, &t.groups);
     for(; !upb_inttable_done(&iter); upb_inttable_next(&iter))
-      free(upb_value_getptr(upb_inttable_iter_value(&iter)));
+      upb_gfree(upb_value_getptr(upb_inttable_iter_value(&iter)));
   }
   upb_inttable_uninit(&t.groups);
 err3:
@@ -3407,7 +3505,7 @@ static void merge(upb_refcounted *r, upb_refcounted *from) {
 
   if (merged(r, from)) return;
   *r->group += *from->group;
-  free(from->group);
+  upb_gfree(from->group);
   base = from;
 
   /* Set all refcount pointers in the "from" chain to the merged refcount.
@@ -3441,7 +3539,7 @@ static void unref(const upb_refcounted *r) {
   if (unrefgroup(r->group)) {
     const upb_refcounted *o;
 
-    free(r->group);
+    upb_gfree(r->group);
 
     /* In two passes, since release_ref2 needs a guarantee that any subobjs
      * are alive. */
@@ -3485,13 +3583,10 @@ bool upb_refcounted_init(upb_refcounted *r,
   r->vtbl = vtbl;
   r->individual_count = 0;
   r->is_frozen = false;
-  r->group = malloc(sizeof(*r->group));
+  r->group = upb_gmalloc(sizeof(*r->group));
   if (!r->group) return false;
   *r->group = 0;
-  if (!trackinit(r)) {
-    free(r->group);
-    return false;
-  }
+  trackinit(r);
   upb_refcounted_ref(r, owner);
   return true;
 }
@@ -3550,15 +3645,16 @@ void upb_refcounted_checkref(const upb_refcounted *r, const void *owner) {
 bool upb_refcounted_freeze(upb_refcounted *const*roots, int n, upb_status *s,
                            int maxdepth) {
   int i;
+  bool ret;
   for (i = 0; i < n; i++) {
     assert(!roots[i]->is_frozen);
   }
-  return freeze(roots, n, s, maxdepth);
+  ret = freeze(roots, n, s, maxdepth);
+  assert(!s || ret == upb_ok(s));
+  return ret;
 }
 
 
-#include <stdlib.h>
-
 /* Fallback implementation if the shim is not specialized by the JIT. */
 #define SHIM_WRITER(type, ctype)                                              \
   bool upb_shim_set ## type (void *c, const void *hd, ctype val) {            \
@@ -3584,14 +3680,14 @@ bool upb_shim_set(upb_handlers *h, const upb_fielddef *f, size_t offset,
   upb_handlerattr attr = UPB_HANDLERATTR_INITIALIZER;
   bool ok;
 
-  upb_shim_data *d = malloc(sizeof(*d));
+  upb_shim_data *d = upb_gmalloc(sizeof(*d));
   if (!d) return false;
   d->offset = offset;
   d->hasbit = hasbit;
 
   upb_handlerattr_sethandlerdata(&attr, d);
   upb_handlerattr_setalwaysok(&attr, true);
-  upb_handlers_addcleanup(h, d, free);
+  upb_handlers_addcleanup(h, d, upb_gfree);
 
 #define TYPE(u, l) \
   case UPB_TYPE_##u: \
@@ -3642,7 +3738,6 @@ const upb_shim_data *upb_shim_getdata(const upb_handlers *h, upb_selector_t s,
 }
 
 
-#include <stdlib.h>
 #include <string.h>
 
 static void upb_symtab_free(upb_refcounted *r) {
@@ -3654,13 +3749,17 @@ static void upb_symtab_free(upb_refcounted *r) {
     upb_def_unref(def, s);
   }
   upb_strtable_uninit(&s->symtab);
-  free(s);
+  upb_gfree(s);
 }
 
-
 upb_symtab *upb_symtab_new(const void *owner) {
   static const struct upb_refcounted_vtbl vtbl = {NULL, &upb_symtab_free};
-  upb_symtab *s = malloc(sizeof(*s));
+
+  upb_symtab *s = upb_gmalloc(sizeof(*s));
+  if (!s) {
+    return NULL;
+  }
+
   upb_refcounted_init(upb_symtab_upcast_mutable(s), &vtbl, owner);
   upb_strtable_init(&s->symtab, UPB_CTYPE_PTR);
   return s;
@@ -3834,14 +3933,23 @@ oom:
 
 /* TODO(haberman): we need a lot more testing of error conditions.
  * The came_from_user stuff in particular is not tested. */
-bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, int n, void *ref_donor,
-                    upb_status *status) {
-  int i;
+static bool symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
+                       void *ref_donor, upb_refcounted *freeze_also,
+                       upb_status *status) {
+  size_t i;
+  size_t add_n;
+  size_t freeze_n;
   upb_strtable_iter iter;
+  upb_refcounted **add_objs = NULL;
   upb_def **add_defs = NULL;
+  size_t add_objs_size;
   upb_strtable addtab;
   upb_inttable seen;
 
+  if (n == 0 && !freeze_also) {
+    return true;
+  }
+
   assert(!upb_symtab_isfrozen(s));
   if (!upb_strtable_init(&addtab, UPB_CTYPE_PTR)) {
     upb_status_seterrmsg(status, "out of memory");
@@ -3983,15 +4091,38 @@ bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, int n, void *ref_donor,
     }
   }
 
-  /* We need an array of the defs in addtab, for passing to upb_def_freeze. */
-  add_defs = malloc(sizeof(void*) * upb_strtable_count(&addtab));
+  /* We need an array of the defs in addtab, for passing to
+   * upb_refcounted_freeze(). */
+  add_objs_size = upb_strtable_count(&addtab);
+  if (freeze_also) {
+    add_objs_size++;
+  }
+
+  add_defs = upb_gmalloc(sizeof(void*) * add_objs_size);
   if (add_defs == NULL) goto oom_err;
   upb_strtable_begin(&iter, &addtab);
-  for (n = 0; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
-    add_defs[n++] = upb_value_getptr(upb_strtable_iter_value(&iter));
+  for (add_n = 0; !upb_strtable_done(&iter); upb_strtable_next(&iter)) {
+    add_defs[add_n++] = upb_value_getptr(upb_strtable_iter_value(&iter));
   }
 
-  if (!upb_def_freeze(add_defs, n, status)) goto err;
+  /* Validate defs. */
+  if (!_upb_def_validate(add_defs, add_n, status)) {
+    goto err;
+  }
+
+  /* Cheat a little and give the array a new type.
+   * This is probably undefined behavior, but this code will be deleted soon. */
+  add_objs = (upb_refcounted**)add_defs;
+
+  freeze_n = add_n;
+  if (freeze_also) {
+    add_objs[freeze_n++] = freeze_also;
+  }
+
+  if (!upb_refcounted_freeze(add_objs, freeze_n, status,
+                             UPB_MAX_MESSAGE_DEPTH * 2)) {
+    goto err;
+  }
 
   /* This must be delayed until all errors have been detected, since error
    * recovery code uses this table to cleanup defs. */
@@ -3999,8 +4130,8 @@ bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, int n, void *ref_donor,
 
   /* TODO(haberman) we don't properly handle errors after this point (like
    * OOM in upb_strtable_insert() below). */
-  for (i = 0; i < n; i++) {
-    upb_def *def = add_defs[i];
+  for (i = 0; i < add_n; i++) {
+    upb_def *def = (upb_def*)add_objs[i];
     const char *name = upb_def_fullname(def);
     upb_value v;
     bool success;
@@ -4012,7 +4143,7 @@ bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, int n, void *ref_donor,
     success = upb_strtable_insert(&s->symtab, name, upb_value_ptr(def));
     UPB_ASSERT_VAR(success, success == true);
   }
-  free(add_defs);
+  upb_gfree(add_defs);
   return true;
 
 oom_err:
@@ -4033,11 +4164,40 @@ err: {
     }
   }
   upb_strtable_uninit(&addtab);
-  free(add_defs);
+  upb_gfree(add_defs);
   assert(!upb_ok(status));
   return false;
 }
 
+bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
+                    void *ref_donor, upb_status *status) {
+  return symtab_add(s, defs, n, ref_donor, NULL, status);
+}
+
+bool upb_symtab_addfile(upb_symtab *s, upb_filedef *file, upb_status *status) {
+  size_t n;
+  size_t i;
+  upb_def **defs;
+  bool ret;
+
+  n = upb_filedef_defcount(file);
+  defs = upb_gmalloc(sizeof(*defs) * n);
+
+  if (defs == NULL) {
+    upb_status_seterrmsg(status, "Out of memory");
+    return false;
+  }
+
+  for (i = 0; i < n; i++) {
+    defs[i] = upb_filedef_mutabledef(file, i);
+  }
+
+  ret = symtab_add(s, defs, n, NULL, upb_filedef_upcast_mutable(file), status);
+
+  upb_gfree(defs);
+  return ret;
+}
+
 /* Iteration. */
 
 static void advance_to_matching(upb_symtab_iter *iter) {
@@ -4076,7 +4236,6 @@ const upb_def *upb_symtab_iter_def(const upb_symtab_iter *iter) {
 */
 
 
-#include <stdlib.h>
 #include <string.h>
 
 #define UPB_MAXARRSIZE 16  /* 64k. */
@@ -4085,6 +4244,17 @@ const upb_def *upb_symtab_iter_def(const upb_symtab_iter *iter) {
 #define ARRAY_SIZE(x) \
     ((sizeof(x)/sizeof(0[x])) / ((size_t)(!(sizeof(x) % sizeof(0[x])))))
 
+#ifdef NDEBUG
+static void upb_check_alloc(upb_table *t, upb_alloc *a) {
+  UPB_UNUSED(t);
+  UPB_UNUSED(a);
+}
+#else
+static void upb_check_alloc(upb_table *t, upb_alloc *a) {
+  assert(t->alloc == a);
+}
+#endif
+
 static const double MAX_LOAD = 0.85;
 
 /* The minimum utilization of the array part of a mixed hash/array table.  This
@@ -4102,11 +4272,11 @@ int log2ceil(uint64_t v) {
   return UPB_MIN(UPB_MAXARRSIZE, ret);
 }
 
-char *upb_strdup(const char *s) {
-  return upb_strdup2(s, strlen(s));
+char *upb_strdup(const char *s, upb_alloc *a) {
+  return upb_strdup2(s, strlen(s), a);
 }
 
-char *upb_strdup2(const char *s, size_t len) {
+char *upb_strdup2(const char *s, size_t len, upb_alloc *a) {
   size_t n;
   char *p;
 
@@ -4115,7 +4285,7 @@ char *upb_strdup2(const char *s, size_t len) {
   /* Always null-terminate, even if binary data; but don't rely on the input to
    * have a null-terminating byte since it may be a raw binary buffer. */
   n = len + 1;
-  p = malloc(n);
+  p = upb_malloc(a, n);
   if (p) {
     memcpy(p, s, len);
     p[len] = 0;
@@ -4163,16 +4333,20 @@ static bool isfull(upb_table *t) {
   }
 }
 
-static bool init(upb_table *t, upb_ctype_t ctype, uint8_t size_lg2) {
+static bool init(upb_table *t, upb_ctype_t ctype, uint8_t size_lg2,
+                 upb_alloc *a) {
   size_t bytes;
 
   t->count = 0;
   t->ctype = ctype;
   t->size_lg2 = size_lg2;
   t->mask = upb_table_size(t) ? upb_table_size(t) - 1 : 0;
+#ifndef NDEBUG
+  t->alloc = a;
+#endif
   bytes = upb_table_size(t) * sizeof(upb_tabent);
   if (bytes > 0) {
-    t->entries = malloc(bytes);
+    t->entries = upb_malloc(a, bytes);
     if (!t->entries) return false;
     memset(mutable_entries(t), 0, bytes);
   } else {
@@ -4181,7 +4355,10 @@ static bool init(upb_table *t, upb_ctype_t ctype, uint8_t size_lg2) {
   return true;
 }
 
-static void uninit(upb_table *t) { free(mutable_entries(t)); }
+static void uninit(upb_table *t, upb_alloc *a) {
+  upb_check_alloc(t, a);
+  upb_free(a, mutable_entries(t));
+}
 
 static upb_tabent *emptyent(upb_table *t) {
   upb_tabent *e = mutable_entries(t) + upb_table_size(t);
@@ -4334,8 +4511,8 @@ static size_t begin(const upb_table *t) {
 
 /* A simple "subclass" of upb_table that only adds a hash function for strings. */
 
-static upb_tabkey strcopy(lookupkey_t k2) {
-  char *str = malloc(k2.str.len + sizeof(uint32_t) + 1);
+static upb_tabkey strcopy(lookupkey_t k2, upb_alloc *a) {
+  char *str = upb_malloc(a, k2.str.len + sizeof(uint32_t) + 1);
   if (str == NULL) return 0;
   memcpy(str, &k2.str.len, sizeof(uint32_t));
   memcpy(str + sizeof(uint32_t), k2.str.str, k2.str.len + 1);
@@ -4354,51 +4531,56 @@ static bool streql(upb_tabkey k1, lookupkey_t k2) {
   return len == k2.str.len && memcmp(str, k2.str.str, len) == 0;
 }
 
-bool upb_strtable_init(upb_strtable *t, upb_ctype_t ctype) {
-  return init(&t->t, ctype, 2);
+bool upb_strtable_init2(upb_strtable *t, upb_ctype_t ctype, upb_alloc *a) {
+  return init(&t->t, ctype, 2, a);
 }
 
-void upb_strtable_uninit(upb_strtable *t) {
+void upb_strtable_uninit2(upb_strtable *t, upb_alloc *a) {
   size_t i;
   for (i = 0; i < upb_table_size(&t->t); i++)
-    free((void*)t->t.entries[i].key);
-  uninit(&t->t);
+    upb_free(a, (void*)t->t.entries[i].key);
+  uninit(&t->t, a);
 }
 
-bool upb_strtable_resize(upb_strtable *t, size_t size_lg2) {
+bool upb_strtable_resize(upb_strtable *t, size_t size_lg2, upb_alloc *a) {
   upb_strtable new_table;
   upb_strtable_iter i;
 
-  if (!init(&new_table.t, t->t.ctype, size_lg2))
+  upb_check_alloc(&t->t, a);
+
+  if (!init(&new_table.t, t->t.ctype, size_lg2, a))
     return false;
   upb_strtable_begin(&i, t);
   for ( ; !upb_strtable_done(&i); upb_strtable_next(&i)) {
-    upb_strtable_insert2(
+    upb_strtable_insert3(
         &new_table,
         upb_strtable_iter_key(&i),
         upb_strtable_iter_keylength(&i),
-        upb_strtable_iter_value(&i));
+        upb_strtable_iter_value(&i),
+        a);
   }
-  upb_strtable_uninit(t);
+  upb_strtable_uninit2(t, a);
   *t = new_table;
   return true;
 }
 
-bool upb_strtable_insert2(upb_strtable *t, const char *k, size_t len,
-                          upb_value v) {
+bool upb_strtable_insert3(upb_strtable *t, const char *k, size_t len,
+                          upb_value v, upb_alloc *a) {
   lookupkey_t key;
   upb_tabkey tabkey;
   uint32_t hash;
 
+  upb_check_alloc(&t->t, a);
+
   if (isfull(&t->t)) {
     /* Need to resize.  New table of double the size, add old elements to it. */
-    if (!upb_strtable_resize(t, t->t.size_lg2 + 1)) {
+    if (!upb_strtable_resize(t, t->t.size_lg2 + 1, a)) {
       return false;
     }
   }
 
   key = strkey2(k, len);
-  tabkey = strcopy(key);
+  tabkey = strcopy(key, a);
   if (tabkey == 0) return false;
 
   hash = MurmurHash2(key.str.str, key.str.len, 0);
@@ -4412,12 +4594,12 @@ bool upb_strtable_lookup2(const upb_strtable *t, const char *key, size_t len,
   return lookup(&t->t, strkey2(key, len), v, hash, &streql);
 }
 
-bool upb_strtable_remove2(upb_strtable *t, const char *key, size_t len,
-                         upb_value *val) {
+bool upb_strtable_remove3(upb_strtable *t, const char *key, size_t len,
+                         upb_value *val, upb_alloc *alloc) {
   uint32_t hash = MurmurHash2(key, strlen(key), 0);
   upb_tabkey tabkey;
   if (rm(&t->t, strkey2(key, len), val, &tabkey, hash, &streql)) {
-    free((void*)tabkey);
+    upb_free(alloc, (void*)tabkey);
     return true;
   } else {
     return false;
@@ -4444,12 +4626,12 @@ bool upb_strtable_done(const upb_strtable_iter *i) {
          upb_tabent_isempty(str_tabent(i));
 }
 
-const char *upb_strtable_iter_key(upb_strtable_iter *i) {
+const char *upb_strtable_iter_key(const upb_strtable_iter *i) {
   assert(!upb_strtable_done(i));
   return upb_tabstr(str_tabent(i)->key, NULL);
 }
 
-size_t upb_strtable_iter_keylength(upb_strtable_iter *i) {
+size_t upb_strtable_iter_keylength(const upb_strtable_iter *i) {
   uint32_t len;
   assert(!upb_strtable_done(i));
   upb_tabstr(str_tabent(i)->key, &len);
@@ -4524,18 +4706,18 @@ static void check(upb_inttable *t) {
 }
 
 bool upb_inttable_sizedinit(upb_inttable *t, upb_ctype_t ctype,
-                            size_t asize, int hsize_lg2) {
+                            size_t asize, int hsize_lg2, upb_alloc *a) {
   size_t array_bytes;
 
-  if (!init(&t->t, ctype, hsize_lg2)) return false;
+  if (!init(&t->t, ctype, hsize_lg2, a)) return false;
   /* Always make the array part at least 1 long, so that we know key 0
    * won't be in the hash part, which simplifies things. */
   t->array_size = UPB_MAX(1, asize);
   t->array_count = 0;
   array_bytes = t->array_size * sizeof(upb_value);
-  t->array = malloc(array_bytes);
+  t->array = upb_malloc(a, array_bytes);
   if (!t->array) {
-    uninit(&t->t);
+    uninit(&t->t, a);
     return false;
   }
   memset(mutable_array(t), 0xff, array_bytes);
@@ -4543,22 +4725,23 @@ bool upb_inttable_sizedinit(upb_inttable *t, upb_ctype_t ctype,
   return true;
 }
 
-bool upb_inttable_init(upb_inttable *t, upb_ctype_t ctype) {
-  return upb_inttable_sizedinit(t, ctype, 0, 4);
+bool upb_inttable_init2(upb_inttable *t, upb_ctype_t ctype, upb_alloc *a) {
+  return upb_inttable_sizedinit(t, ctype, 0, 4, a);
 }
 
-void upb_inttable_uninit(upb_inttable *t) {
-  uninit(&t->t);
-  free(mutable_array(t));
+void upb_inttable_uninit2(upb_inttable *t, upb_alloc *a) {
+  uninit(&t->t, a);
+  upb_free(a, mutable_array(t));
 }
 
-bool upb_inttable_insert(upb_inttable *t, uintptr_t key, upb_value val) {
-  /* XXX: Table can't store value (uint64_t)-1.  Need to somehow statically
-   * guarantee that this is not necessary, or fix the limitation. */
+bool upb_inttable_insert2(upb_inttable *t, uintptr_t key, upb_value val,
+                          upb_alloc *a) {
   upb_tabval tabval;
   tabval.val = val.val;
   UPB_UNUSED(tabval);
-  assert(upb_arrhas(tabval));
+  assert(upb_arrhas(tabval));  /* This will reject (uint64_t)-1.  Fix this. */
+
+  upb_check_alloc(&t->t, a);
 
   if (key < t->array_size) {
     assert(!upb_arrhas(t->array[key]));
@@ -4569,8 +4752,11 @@ bool upb_inttable_insert(upb_inttable *t, uintptr_t key, upb_value val) {
       /* Need to resize the hash part, but we re-use the array part. */
       size_t i;
       upb_table new_table;
-      if (!init(&new_table, t->t.ctype, t->t.size_lg2 + 1))
+
+      if (!init(&new_table, t->t.ctype, t->t.size_lg2 + 1, a)) {
         return false;
+      }
+
       for (i = begin(&t->t); i < upb_table_size(&t->t); i = next(&t->t, i)) {
         const upb_tabent *e = &t->t.entries[i];
         uint32_t hash;
@@ -4583,7 +4769,7 @@ bool upb_inttable_insert(upb_inttable *t, uintptr_t key, upb_value val) {
 
       assert(t->t.count == new_table.count);
 
-      uninit(&t->t);
+      uninit(&t->t, a);
       t->t = new_table;
     }
     insert(&t->t, intkey(key), key, val, upb_inthash(key), &inthash, &inteql);
@@ -4629,8 +4815,9 @@ bool upb_inttable_remove(upb_inttable *t, uintptr_t key, upb_value *val) {
   return success;
 }
 
-bool upb_inttable_push(upb_inttable *t, upb_value val) {
-  return upb_inttable_insert(t, upb_inttable_count(t), val);
+bool upb_inttable_push2(upb_inttable *t, upb_value val, upb_alloc *a) {
+  upb_check_alloc(&t->t, a);
+  return upb_inttable_insert2(t, upb_inttable_count(t), val, a);
 }
 
 upb_value upb_inttable_pop(upb_inttable *t) {
@@ -4640,8 +4827,10 @@ upb_value upb_inttable_pop(upb_inttable *t) {
   return val;
 }
 
-bool upb_inttable_insertptr(upb_inttable *t, const void *key, upb_value val) {
-  return upb_inttable_insert(t, (uintptr_t)key, val);
+bool upb_inttable_insertptr2(upb_inttable *t, const void *key, upb_value val,
+                             upb_alloc *a) {
+  upb_check_alloc(&t->t, a);
+  return upb_inttable_insert2(t, (uintptr_t)key, val, a);
 }
 
 bool upb_inttable_lookupptr(const upb_inttable *t, const void *key,
@@ -4653,7 +4842,7 @@ bool upb_inttable_removeptr(upb_inttable *t, const void *key, upb_value *val) {
   return upb_inttable_remove(t, (uintptr_t)key, val);
 }
 
-void upb_inttable_compact(upb_inttable *t) {
+void upb_inttable_compact2(upb_inttable *t, upb_alloc *a) {
   /* A power-of-two histogram of the table keys. */
   size_t counts[UPB_MAXARRSIZE + 1] = {0};
 
@@ -4665,6 +4854,8 @@ void upb_inttable_compact(upb_inttable *t) {
   int size_lg2;
   upb_inttable new_t;
 
+  upb_check_alloc(&t->t, a);
+
   upb_inttable_begin(&i, t);
   for (; !upb_inttable_done(&i); upb_inttable_next(&i)) {
     uintptr_t key = upb_inttable_iter_key(&i);
@@ -4697,16 +4888,16 @@ void upb_inttable_compact(upb_inttable *t) {
     size_t hash_size = hash_count ? (hash_count / MAX_LOAD) + 1 : 0;
     size_t hashsize_lg2 = log2ceil(hash_size);
 
-    upb_inttable_sizedinit(&new_t, t->t.ctype, arr_size, hashsize_lg2);
+    upb_inttable_sizedinit(&new_t, t->t.ctype, arr_size, hashsize_lg2, a);
     upb_inttable_begin(&i, t);
     for (; !upb_inttable_done(&i); upb_inttable_next(&i)) {
       uintptr_t k = upb_inttable_iter_key(&i);
-      upb_inttable_insert(&new_t, k, upb_inttable_iter_value(&i));
+      upb_inttable_insert2(&new_t, k, upb_inttable_iter_value(&i), a);
     }
     assert(new_t.array_size == arr_size);
     assert(new_t.t.size_lg2 == hashsize_lg2);
   }
-  upb_inttable_uninit(t);
+  upb_inttable_uninit2(t, a);
   *t = new_t;
 }
 
@@ -4982,6 +5173,19 @@ static void nullz(upb_status *status) {
   memcpy(status->msg + sizeof(status->msg) - len, ellipsis, len);
 }
 
+
+/* upb_upberr *****************************************************************/
+
+upb_errorspace upb_upberr = {"upb error"};
+
+void upb_upberr_setoom(upb_status *status) {
+  status->error_space_ = &upb_upberr;
+  upb_status_seterrmsg(status, "Out of memory");
+}
+
+
+/* upb_status *****************************************************************/
+
 void upb_status_clear(upb_status *status) {
   if (!status) return;
   status->ok_ = true;
@@ -5020,58 +5224,298 @@ void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args) {
   nullz(status);
 }
 
-void upb_status_seterrcode(upb_status *status, upb_errorspace *space,
-                           int code) {
-  if (!status) return;
-  status->ok_ = false;
-  status->error_space_ = space;
-  status->code_ = code;
-  space->set_message(status, code);
-}
-
 void upb_status_copy(upb_status *to, const upb_status *from) {
   if (!to) return;
   *to = *from;
 }
-/* This file was generated by upbc (the upb compiler).
+
+
+/* upb_alloc ******************************************************************/
+
+static void *upb_global_allocfunc(upb_alloc *alloc, void *ptr, size_t oldsize,
+                                  size_t size) {
+  UPB_UNUSED(alloc);
+  UPB_UNUSED(oldsize);
+  if (size == 0) {
+    free(ptr);
+    return NULL;
+  } else {
+    return realloc(ptr, size);
+  }
+}
+
+upb_alloc upb_alloc_global = {&upb_global_allocfunc};
+
+
+/* upb_arena ******************************************************************/
+
+/* Be conservative and choose 16 in case anyone is using SSE. */
+static const size_t maxalign = 16;
+
+static size_t align_up(size_t size) {
+  return ((size + maxalign - 1) / maxalign) * maxalign;
+}
+
+typedef struct mem_block {
+  struct mem_block *next;
+  size_t size;
+  size_t used;
+  bool owned;
+  /* Data follows. */
+} mem_block;
+
+typedef struct cleanup_ent {
+  struct cleanup_ent *next;
+  upb_cleanup_func *cleanup;
+  void *ud;
+} cleanup_ent;
+
+static void upb_arena_addblock(upb_arena *a, void *ptr, size_t size,
+                               bool owned) {
+  mem_block *block = ptr;
+
+  block->next = a->block_head;
+  block->size = size;
+  block->used = align_up(sizeof(mem_block));
+  block->owned = owned;
+
+  a->block_head = block;
+
+  /* TODO(haberman): ASAN poison. */
+}
+
+
+static mem_block *upb_arena_allocblock(upb_arena *a, size_t size) {
+  size_t block_size = UPB_MAX(size, a->next_block_size) + sizeof(mem_block);
+  mem_block *block = upb_malloc(a->block_alloc, block_size);
+
+  if (!block) {
+    return NULL;
+  }
+
+  upb_arena_addblock(a, block, block_size, true);
+  a->next_block_size = UPB_MIN(block_size * 2, a->max_block_size);
+
+  return block;
+}
+
+static void *upb_arena_doalloc(upb_alloc *alloc, void *ptr, size_t oldsize,
+                               size_t size) {
+  upb_arena *a = (upb_arena*)alloc;  /* upb_alloc is initial member. */
+  mem_block *block = a->block_head;
+  void *ret;
+
+  if (size == 0) {
+    return NULL;  /* We are an arena, don't need individual frees. */
+  }
+
+  size = align_up(size);
+
+  /* TODO(haberman): special-case if this is a realloc of the last alloc? */
+
+  if (!block || block->size - block->used < size) {
+    /* Slow path: have to allocate a new block. */
+    block = upb_arena_allocblock(a, size);
+
+    if (!block) {
+      return NULL;  /* Out of memory. */
+    }
+  }
+
+  ret = (char*)block + block->used;
+  block->used += size;
+
+  if (oldsize > 0) {
+    memcpy(ret, ptr, oldsize);  /* Preserve existing data. */
+  }
+
+  /* TODO(haberman): ASAN unpoison. */
+
+  a->bytes_allocated += size;
+  return ret;
+}
+
+/* Public Arena API ***********************************************************/
+
+void upb_arena_init(upb_arena *a) {
+  a->alloc.func = &upb_arena_doalloc;
+  a->block_alloc = &upb_alloc_global;
+  a->bytes_allocated = 0;
+  a->next_block_size = 256;
+  a->max_block_size = 16384;
+  a->cleanup_head = NULL;
+  a->block_head = NULL;
+}
+
+void upb_arena_init2(upb_arena *a, void *mem, size_t size, upb_alloc *alloc) {
+  upb_arena_init(a);
+
+  if (size > sizeof(mem_block)) {
+    upb_arena_addblock(a, mem, size, false);
+  }
+
+  if (alloc) {
+    a->block_alloc = alloc;
+  }
+}
+
+void upb_arena_uninit(upb_arena *a) {
+  cleanup_ent *ent = a->cleanup_head;
+  mem_block *block = a->block_head;
+
+  while (ent) {
+    ent->cleanup(ent->ud);
+    ent = ent->next;
+  }
+
+  /* Must do this after running cleanup functions, because this will delete
+   * the memory we store our cleanup entries in! */
+  while (block) {
+    mem_block *next = block->next;
+
+    if (block->owned) {
+      upb_free(a->block_alloc, block);
+    }
+
+    block = next;
+  }
+}
+
+bool upb_arena_addcleanup(upb_arena *a, upb_cleanup_func *func, void *ud) {
+  cleanup_ent *ent = upb_malloc(&a->alloc, sizeof(cleanup_ent));
+  if (!ent) {
+    return false;  /* Out of memory. */
+  }
+
+  ent->cleanup = func;
+  ent->ud = ud;
+  ent->next = a->cleanup_head;
+  a->cleanup_head = ent;
+
+  return true;
+}
+
+size_t upb_arena_bytesallocated(const upb_arena *a) {
+  return a->bytes_allocated;
+}
+
+
+/* Standard error functions ***************************************************/
+
+static bool default_err(void *ud, const upb_status *status) {
+  UPB_UNUSED(ud);
+  UPB_UNUSED(status);
+  return false;
+}
+
+static bool write_err_to(void *ud, const upb_status *status) {
+  upb_status *copy_to = ud;
+  upb_status_copy(copy_to, status);
+  return false;
+}
+
+
+/* upb_env ********************************************************************/
+
+void upb_env_initonly(upb_env *e) {
+  e->ok_ = true;
+  e->error_func_ = &default_err;
+  e->error_ud_ = NULL;
+}
+
+void upb_env_init(upb_env *e) {
+  upb_arena_init(&e->arena_);
+  upb_env_initonly(e);
+}
+
+void upb_env_init2(upb_env *e, void *mem, size_t n, upb_alloc *alloc) {
+  upb_arena_init2(&e->arena_, mem, n, alloc);
+  upb_env_initonly(e);
+}
+
+void upb_env_uninit(upb_env *e) {
+  upb_arena_uninit(&e->arena_);
+}
+
+void upb_env_seterrorfunc(upb_env *e, upb_error_func *func, void *ud) {
+  e->error_func_ = func;
+  e->error_ud_ = ud;
+}
+
+void upb_env_reporterrorsto(upb_env *e, upb_status *s) {
+  e->error_func_ = &write_err_to;
+  e->error_ud_ = s;
+}
+
+bool upb_env_reporterror(upb_env *e, const upb_status *status) {
+  e->ok_ = false;
+  return e->error_func_(e->error_ud_, status);
+}
+
+void *upb_env_malloc(upb_env *e, size_t size) {
+  return upb_malloc(&e->arena_.alloc, size);
+}
+
+void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size) {
+  return upb_realloc(&e->arena_.alloc, ptr, oldsize, size);
+}
+
+void upb_env_free(upb_env *e, void *ptr) {
+  upb_free(&e->arena_.alloc, ptr);
+}
+
+bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud) {
+  return upb_arena_addcleanup(&e->arena_, func, ud);
+}
+
+size_t upb_env_bytesallocated(const upb_env *e) {
+  return upb_arena_bytesallocated(&e->arena_);
+}
+/* This file was generated by upbc (the upb compiler) from the input
+ * file:
+ *
+ *     upb/descriptor/descriptor.proto
+ *
  * Do not edit -- your changes will be discarded when the file is
  * regenerated. */
 
+#include <assert.h>
+
 
 static const upb_msgdef msgs[22];
 static const upb_fielddef fields[105];
 static const upb_enumdef enums[5];
-static const upb_tabent strentries[268];
+static const upb_tabent strentries[236];
 static const upb_tabent intentries[18];
 static const upb_tabval arrays[184];
 
 #ifdef UPB_DEBUG_REFS
-static upb_inttable reftables[266];
+static upb_inttable reftables[264];
 #endif
 
 static const upb_msgdef msgs[22] = {
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto", 40, 8, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[0], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[0]),&reftables[0], &reftables[1]),
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ExtensionRange", 4, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[11], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[16]),&reftables[2], &reftables[3]),
-  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ReservedRange", 4, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[14], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[20]),&reftables[4], &reftables[5]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumDescriptorProto", 11, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[17], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[24]),&reftables[6], &reftables[7]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumOptions", 8, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[0], &arrays[21], 4, 2), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[28]),&reftables[8], &reftables[9]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumValueDescriptorProto", 8, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[25], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[32]),&reftables[10], &reftables[11]),
-  UPB_MSGDEF_INIT("google.protobuf.EnumValueOptions", 7, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[2], &arrays[29], 2, 1), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[36]),&reftables[12], &reftables[13]),
-  UPB_MSGDEF_INIT("google.protobuf.FieldDescriptorProto", 23, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[31], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[40]),&reftables[14], &reftables[15]),
-  UPB_MSGDEF_INIT("google.protobuf.FieldOptions", 12, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[4], &arrays[42], 11, 6), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[56]),&reftables[16], &reftables[17]),
-  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorProto", 42, 6, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[53], 13, 12), UPB_STRTABLE_INIT(12, 15, UPB_CTYPE_PTR, 4, &strentries[72]),&reftables[18], &reftables[19]),
-  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorSet", 6, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[66], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[88]),&reftables[20], &reftables[21]),
-  UPB_MSGDEF_INIT("google.protobuf.FileOptions", 31, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[6], &arrays[68], 39, 15), UPB_STRTABLE_INIT(16, 31, UPB_CTYPE_PTR, 5, &strentries[92]),&reftables[22], &reftables[23]),
-  UPB_MSGDEF_INIT("google.protobuf.MessageOptions", 10, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[8], &arrays[107], 8, 4), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[124]),&reftables[24], &reftables[25]),
-  UPB_MSGDEF_INIT("google.protobuf.MethodDescriptorProto", 15, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[115], 7, 6), UPB_STRTABLE_INIT(6, 7, UPB_CTYPE_PTR, 3, &strentries[132]),&reftables[26], &reftables[27]),
-  UPB_MSGDEF_INIT("google.protobuf.MethodOptions", 7, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[10], &arrays[122], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[140]),&reftables[28], &reftables[29]),
-  UPB_MSGDEF_INIT("google.protobuf.OneofDescriptorProto", 5, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[123], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[144]),&reftables[30], &reftables[31]),
-  UPB_MSGDEF_INIT("google.protobuf.ServiceDescriptorProto", 11, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[125], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[148]),&reftables[32], &reftables[33]),
-  UPB_MSGDEF_INIT("google.protobuf.ServiceOptions", 7, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[14], &arrays[129], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[152]),&reftables[34], &reftables[35]),
-  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo", 6, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[130], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[156]),&reftables[36], &reftables[37]),
-  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo.Location", 19, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[132], 7, 5), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[160]),&reftables[38], &reftables[39]),
-  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption", 18, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[139], 9, 7), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[168]),&reftables[40], &reftables[41]),
-  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption.NamePart", 6, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[148], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[184]),&reftables[42], &reftables[43]),
+  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto", 40, 8, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[0], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[0]), false, UPB_SYNTAX_PROTO2, &reftables[0], &reftables[1]),
+  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ExtensionRange", 4, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[11], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[16]), false, UPB_SYNTAX_PROTO2, &reftables[2], &reftables[3]),
+  UPB_MSGDEF_INIT("google.protobuf.DescriptorProto.ReservedRange", 4, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[14], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[20]), false, UPB_SYNTAX_PROTO2, &reftables[4], &reftables[5]),
+  UPB_MSGDEF_INIT("google.protobuf.EnumDescriptorProto", 11, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[17], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[24]), false, UPB_SYNTAX_PROTO2, &reftables[6], &reftables[7]),
+  UPB_MSGDEF_INIT("google.protobuf.EnumOptions", 8, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[0], &arrays[21], 4, 2), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[28]), false, UPB_SYNTAX_PROTO2, &reftables[8], &reftables[9]),
+  UPB_MSGDEF_INIT("google.protobuf.EnumValueDescriptorProto", 8, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[25], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[32]), false, UPB_SYNTAX_PROTO2, &reftables[10], &reftables[11]),
+  UPB_MSGDEF_INIT("google.protobuf.EnumValueOptions", 7, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[2], &arrays[29], 2, 1), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[36]), false, UPB_SYNTAX_PROTO2, &reftables[12], &reftables[13]),
+  UPB_MSGDEF_INIT("google.protobuf.FieldDescriptorProto", 23, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[31], 11, 10), UPB_STRTABLE_INIT(10, 15, UPB_CTYPE_PTR, 4, &strentries[40]), false, UPB_SYNTAX_PROTO2, &reftables[14], &reftables[15]),
+  UPB_MSGDEF_INIT("google.protobuf.FieldOptions", 12, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[4], &arrays[42], 11, 6), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[56]), false, UPB_SYNTAX_PROTO2, &reftables[16], &reftables[17]),
+  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorProto", 42, 6, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[53], 13, 12), UPB_STRTABLE_INIT(12, 15, UPB_CTYPE_PTR, 4, &strentries[72]), false, UPB_SYNTAX_PROTO2, &reftables[18], &reftables[19]),
+  UPB_MSGDEF_INIT("google.protobuf.FileDescriptorSet", 6, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[66], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[88]), false, UPB_SYNTAX_PROTO2, &reftables[20], &reftables[21]),
+  UPB_MSGDEF_INIT("google.protobuf.FileOptions", 31, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[6], &arrays[68], 39, 15), UPB_STRTABLE_INIT(16, 31, UPB_CTYPE_PTR, 5, &strentries[92]), false, UPB_SYNTAX_PROTO2, &reftables[22], &reftables[23]),
+  UPB_MSGDEF_INIT("google.protobuf.MessageOptions", 10, 1, UPB_INTTABLE_INIT(1, 1, UPB_CTYPE_PTR, 1, &intentries[8], &arrays[107], 8, 4), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[124]), false, UPB_SYNTAX_PROTO2, &reftables[24], &reftables[25]),
+  UPB_MSGDEF_INIT("google.protobuf.MethodDescriptorProto", 15, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[115], 7, 6), UPB_STRTABLE_INIT(6, 7, UPB_CTYPE_PTR, 3, &strentries[132]), false, UPB_SYNTAX_PROTO2, &reftables[26], &reftables[27]),
+  UPB_MSGDEF_INIT("google.protobuf.MethodOptions", 7, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[10], &arrays[122], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[140]), false, UPB_SYNTAX_PROTO2, &reftables[28], &reftables[29]),
+  UPB_MSGDEF_INIT("google.protobuf.OneofDescriptorProto", 5, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[123], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[144]), false, UPB_SYNTAX_PROTO2, &reftables[30], &reftables[31]),
+  UPB_MSGDEF_INIT("google.protobuf.ServiceDescriptorProto", 11, 2, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[125], 4, 3), UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_PTR, 2, &strentries[148]), false, UPB_SYNTAX_PROTO2, &reftables[32], &reftables[33]),
+  UPB_MSGDEF_INIT("google.protobuf.ServiceOptions", 7, 1, UPB_INTTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &intentries[14], &arrays[129], 1, 0), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[152]), false, UPB_SYNTAX_PROTO2, &reftables[34], &reftables[35]),
+  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo", 6, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[130], 2, 1), UPB_STRTABLE_INIT(1, 3, UPB_CTYPE_PTR, 2, &strentries[156]), false, UPB_SYNTAX_PROTO2, &reftables[36], &reftables[37]),
+  UPB_MSGDEF_INIT("google.protobuf.SourceCodeInfo.Location", 19, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[132], 7, 5), UPB_STRTABLE_INIT(5, 7, UPB_CTYPE_PTR, 3, &strentries[160]), false, UPB_SYNTAX_PROTO2, &reftables[38], &reftables[39]),
+  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption", 18, 1, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[139], 9, 7), UPB_STRTABLE_INIT(7, 15, UPB_CTYPE_PTR, 4, &strentries[168]), false, UPB_SYNTAX_PROTO2, &reftables[40], &reftables[41]),
+  UPB_MSGDEF_INIT("google.protobuf.UninterpretedOption.NamePart", 6, 0, UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_PTR, 0, NULL, &arrays[148], 3, 2), UPB_STRTABLE_INIT(2, 3, UPB_CTYPE_PTR, 2, &strentries[184]), false, UPB_SYNTAX_PROTO2, &reftables[42], &reftables[43]),
 };
 
 static const upb_fielddef fields[105] = {
@@ -5084,18 +5528,18 @@ static const upb_fielddef fields[105] = {
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "ctype", 1, &msgs[8], (const upb_def*)(&enums[2]), 6, 1, {0},&reftables[56], &reftables[57]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "default_value", 7, &msgs[7], NULL, 16, 7, {0},&reftables[58], &reftables[59]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_STRING, 0, false, false, false, false, "dependency", 3, &msgs[9], NULL, 30, 8, {0},&reftables[60], &reftables[61]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 1, &msgs[6], NULL, 6, 1, {0},&reftables[62], &reftables[63]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[4], NULL, 7, 2, {0},&reftables[64], &reftables[65]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[17], NULL, 6, 1, {0},&reftables[66], &reftables[67]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[8], NULL, 8, 3, {0},&reftables[68], &reftables[69]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[14], NULL, 6, 1, {0},&reftables[70], &reftables[71]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[12], NULL, 8, 3, {0},&reftables[72], &reftables[73]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 23, &msgs[11], NULL, 21, 10, {0},&reftables[74], &reftables[75]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[12], NULL, 8, 3, {0},&reftables[62], &reftables[63]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[8], NULL, 8, 3, {0},&reftables[64], &reftables[65]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[14], NULL, 6, 1, {0},&reftables[66], &reftables[67]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 23, &msgs[11], NULL, 21, 10, {0},&reftables[68], &reftables[69]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 3, &msgs[4], NULL, 7, 2, {0},&reftables[70], &reftables[71]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 33, &msgs[17], NULL, 6, 1, {0},&reftables[72], &reftables[73]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "deprecated", 1, &msgs[6], NULL, 6, 1, {0},&reftables[74], &reftables[75]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_DOUBLE, 0, false, false, false, false, "double_value", 6, &msgs[20], NULL, 11, 4, {0},&reftables[76], &reftables[77]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "end", 2, &msgs[2], NULL, 3, 1, {0},&reftables[78], &reftables[79]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "end", 2, &msgs[1], NULL, 3, 1, {0},&reftables[80], &reftables[81]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 5, &msgs[9], (const upb_def*)(&msgs[3]), 13, 1, {0},&reftables[82], &reftables[83]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 4, &msgs[0], (const upb_def*)(&msgs[3]), 18, 2, {0},&reftables[84], &reftables[85]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 4, &msgs[0], (const upb_def*)(&msgs[3]), 18, 2, {0},&reftables[82], &reftables[83]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "enum_type", 5, &msgs[9], (const upb_def*)(&msgs[3]), 13, 1, {0},&reftables[84], &reftables[85]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "extendee", 2, &msgs[7], NULL, 7, 2, {0},&reftables[86], &reftables[87]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "extension", 6, &msgs[0], (const upb_def*)(&msgs[7]), 24, 4, {0},&reftables[88], &reftables[89]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "extension", 7, &msgs[9], (const upb_def*)(&msgs[7]), 19, 3, {0},&reftables[90], &reftables[91]),
@@ -5124,32 +5568,32 @@ static const upb_fielddef fields[105] = {
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "message_set_wire_format", 1, &msgs[12], NULL, 6, 1, {0},&reftables[136], &reftables[137]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "message_type", 4, &msgs[9], (const upb_def*)(&msgs[0]), 10, 0, {0},&reftables[138], &reftables[139]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "method", 2, &msgs[16], (const upb_def*)(&msgs[13]), 6, 0, {0},&reftables[140], &reftables[141]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[9], NULL, 22, 6, {0},&reftables[142], &reftables[143]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[5], NULL, 4, 1, {0},&reftables[144], &reftables[145]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[13], NULL, 4, 1, {0},&reftables[146], &reftables[147]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[3], NULL, 8, 2, {0},&reftables[142], &reftables[143]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[15], NULL, 2, 0, {0},&reftables[144], &reftables[145]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "name", 2, &msgs[20], (const upb_def*)(&msgs[21]), 5, 0, {0},&reftables[146], &reftables[147]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[0], NULL, 32, 8, {0},&reftables[148], &reftables[149]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[3], NULL, 8, 2, {0},&reftables[150], &reftables[151]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[15], NULL, 2, 0, {0},&reftables[152], &reftables[153]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[16], NULL, 8, 2, {0},&reftables[154], &reftables[155]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[7], NULL, 4, 1, {0},&reftables[156], &reftables[157]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "name", 2, &msgs[20], (const upb_def*)(&msgs[21]), 5, 0, {0},&reftables[158], &reftables[159]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[5], NULL, 4, 1, {0},&reftables[150], &reftables[151]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[9], NULL, 22, 6, {0},&reftables[152], &reftables[153]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[7], NULL, 4, 1, {0},&reftables[154], &reftables[155]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[13], NULL, 4, 1, {0},&reftables[156], &reftables[157]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "name", 1, &msgs[16], NULL, 8, 2, {0},&reftables[158], &reftables[159]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REQUIRED, UPB_TYPE_STRING, 0, false, false, false, false, "name_part", 1, &msgs[21], NULL, 2, 0, {0},&reftables[160], &reftables[161]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT64, UPB_INTFMT_VARIABLE, false, false, false, false, "negative_int_value", 5, &msgs[20], NULL, 10, 3, {0},&reftables[162], &reftables[163]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "nested_type", 3, &msgs[0], (const upb_def*)(&msgs[0]), 15, 1, {0},&reftables[164], &reftables[165]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "no_standard_descriptor_accessor", 2, &msgs[12], NULL, 7, 2, {0},&reftables[166], &reftables[167]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 3, &msgs[7], NULL, 10, 3, {0},&reftables[168], &reftables[169]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 2, &msgs[5], NULL, 7, 2, {0},&reftables[170], &reftables[171]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 2, &msgs[5], NULL, 7, 2, {0},&reftables[168], &reftables[169]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "number", 3, &msgs[7], NULL, 10, 3, {0},&reftables[170], &reftables[171]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "objc_class_prefix", 36, &msgs[11], NULL, 24, 13, {0},&reftables[172], &reftables[173]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "oneof_decl", 8, &msgs[0], (const upb_def*)(&msgs[15]), 28, 6, {0},&reftables[174], &reftables[175]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "oneof_index", 9, &msgs[7], NULL, 19, 8, {0},&reftables[176], &reftables[177]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "optimize_for", 9, &msgs[11], (const upb_def*)(&enums[4]), 12, 3, {0},&reftables[178], &reftables[179]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 4, &msgs[13], (const upb_def*)(&msgs[14]), 3, 0, {0},&reftables[180], &reftables[181]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[3], (const upb_def*)(&msgs[4]), 7, 1, {0},&reftables[182], &reftables[183]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 7, &msgs[0], (const upb_def*)(&msgs[12]), 25, 5, {0},&reftables[184], &reftables[185]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[5], (const upb_def*)(&msgs[6]), 3, 0, {0},&reftables[186], &reftables[187]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[9], (const upb_def*)(&msgs[11]), 20, 4, {0},&reftables[188], &reftables[189]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[16], (const upb_def*)(&msgs[17]), 7, 1, {0},&reftables[190], &reftables[191]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[7], (const upb_def*)(&msgs[8]), 3, 0, {0},&reftables[192], &reftables[193]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 7, &msgs[0], (const upb_def*)(&msgs[12]), 25, 5, {0},&reftables[180], &reftables[181]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[9], (const upb_def*)(&msgs[11]), 20, 4, {0},&reftables[182], &reftables[183]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 4, &msgs[13], (const upb_def*)(&msgs[14]), 3, 0, {0},&reftables[184], &reftables[185]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 8, &msgs[7], (const upb_def*)(&msgs[8]), 3, 0, {0},&reftables[186], &reftables[187]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[16], (const upb_def*)(&msgs[17]), 7, 1, {0},&reftables[188], &reftables[189]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[5], (const upb_def*)(&msgs[6]), 3, 0, {0},&reftables[190], &reftables[191]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "options", 3, &msgs[3], (const upb_def*)(&msgs[4]), 7, 1, {0},&reftables[192], &reftables[193]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "output_type", 3, &msgs[13], NULL, 10, 3, {0},&reftables[194], &reftables[195]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "package", 2, &msgs[9], NULL, 25, 7, {0},&reftables[196], &reftables[197]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "packed", 2, &msgs[8], NULL, 7, 2, {0},&reftables[198], &reftables[199]),
@@ -5163,20 +5607,20 @@ static const upb_fielddef fields[105] = {
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "service", 6, &msgs[9], (const upb_def*)(&msgs[16]), 16, 2, {0},&reftables[214], &reftables[215]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_MESSAGE, 0, false, false, false, false, "source_code_info", 9, &msgs[9], (const upb_def*)(&msgs[18]), 21, 5, {0},&reftables[216], &reftables[217]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, true, "span", 2, &msgs[19], NULL, 7, 1, {0},&reftables[218], &reftables[219]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[1], NULL, 2, 0, {0},&reftables[220], &reftables[221]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[2], NULL, 2, 0, {0},&reftables[222], &reftables[223]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[2], NULL, 2, 0, {0},&reftables[220], &reftables[221]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "start", 1, &msgs[1], NULL, 2, 0, {0},&reftables[222], &reftables[223]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BYTES, 0, false, false, false, false, "string_value", 7, &msgs[20], NULL, 12, 5, {0},&reftables[224], &reftables[225]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "syntax", 12, &msgs[9], NULL, 39, 11, {0},&reftables[226], &reftables[227]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "trailing_comments", 4, &msgs[19], NULL, 11, 3, {0},&reftables[228], &reftables[229]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_ENUM, 0, false, false, false, false, "type", 5, &msgs[7], (const upb_def*)(&enums[1]), 12, 5, {0},&reftables[230], &reftables[231]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_STRING, 0, false, false, false, false, "type_name", 6, &msgs[7], NULL, 13, 6, {0},&reftables[232], &reftables[233]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[17], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[234], &reftables[235]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[11], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[234], &reftables[235]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[12], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[236], &reftables[237]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[8], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[238], &reftables[239]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[14], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[240], &reftables[241]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[11], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[242], &reftables[243]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[4], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[244], &reftables[245]),
-  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[6], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[246], &reftables[247]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[6], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[238], &reftables[239]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[4], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[240], &reftables[241]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[8], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[242], &reftables[243]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[14], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[244], &reftables[245]),
+  UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "uninterpreted_option", 999, &msgs[17], (const upb_def*)(&msgs[20]), 5, 0, {0},&reftables[246], &reftables[247]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_MESSAGE, 0, false, false, false, false, "value", 2, &msgs[3], (const upb_def*)(&msgs[5]), 6, 0, {0},&reftables[248], &reftables[249]),
   UPB_FIELDDEF_INIT(UPB_LABEL_OPTIONAL, UPB_TYPE_BOOL, 0, false, false, false, false, "weak", 10, &msgs[8], NULL, 11, 6, {0},&reftables[250], &reftables[251]),
   UPB_FIELDDEF_INIT(UPB_LABEL_REPEATED, UPB_TYPE_INT32, UPB_INTFMT_VARIABLE, false, false, false, false, "weak_dependency", 11, &msgs[9], NULL, 38, 10, {0},&reftables[252], &reftables[253]),
@@ -5190,7 +5634,7 @@ static const upb_enumdef enums[5] = {
   UPB_ENUMDEF_INIT("google.protobuf.FileOptions.OptimizeMode", UPB_STRTABLE_INIT(3, 3, UPB_CTYPE_INT32, 2, &strentries[232]), UPB_INTTABLE_INIT(0, 0, UPB_CTYPE_CSTR, 0, NULL, &arrays[180], 4, 3), 0, &reftables[262], &reftables[263]),
 };
 
-static const upb_tabent strentries[268] = {
+static const upb_tabent strentries[236] = {
   {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "extension"), UPB_TABVALUE_PTR_INIT(&fields[22]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "reserved_name"), UPB_TABVALUE_PTR_INIT(&fields[82]), NULL},
@@ -5204,50 +5648,50 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "nested_type"), UPB_TABVALUE_PTR_INIT(&fields[60]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\016", "\000", "\000", "\000", "reserved_range"), UPB_TABVALUE_PTR_INIT(&fields[83]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[70]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[68]), NULL},
   {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "oneof_decl"), UPB_TABVALUE_PTR_INIT(&fields[65]), NULL},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[20]), &strentries[13]},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[88]), NULL},
+  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[19]), &strentries[13]},
+  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[89]), NULL},
   {UPB_TABKEY_STR("\003", "\000", "\000", "\000", "end"), UPB_TABVALUE_PTR_INIT(&fields[18]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[89]), NULL},
+  {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "start"), UPB_TABVALUE_PTR_INIT(&fields[88]), NULL},
   {UPB_TABKEY_STR("\003", "\000", "\000", "\000", "end"), UPB_TABVALUE_PTR_INIT(&fields[17]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "value"), UPB_TABVALUE_PTR_INIT(&fields[102]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[69]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[53]), &strentries[26]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[100]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[10]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[74]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[49]), &strentries[26]},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[98]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[13]), NULL},
   {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "allow_alias"), UPB_TABVALUE_PTR_INIT(&fields[1]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[63]), NULL},
+  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[62]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[71]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[50]), &strentries[34]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[9]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[73]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[53]), &strentries[34]},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[97]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[15]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "oneof_index"), UPB_TABVALUE_PTR_INIT(&fields[66]), NULL},
   {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "label"), UPB_TABVALUE_PTR_INIT(&fields[40]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[56]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[55]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[62]), &strentries[53]},
+  {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "number"), UPB_TABVALUE_PTR_INIT(&fields[63]), &strentries[53]},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\010", "\000", "\000", "\000", "extendee"), UPB_TABVALUE_PTR_INIT(&fields[21]), NULL},
   {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "type_name"), UPB_TABVALUE_PTR_INIT(&fields[94]), NULL},
   {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "json_name"), UPB_TABVALUE_PTR_INIT(&fields[38]), NULL},
   {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "type"), UPB_TABVALUE_PTR_INIT(&fields[93]), &strentries[50]},
   {UPB_TABKEY_STR("\015", "\000", "\000", "\000", "default_value"), UPB_TABVALUE_PTR_INIT(&fields[7]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[74]), NULL},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[97]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[71]), NULL},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[99]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "weak"), UPB_TABVALUE_PTR_INIT(&fields[103]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
@@ -5260,13 +5704,13 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "ctype"), UPB_TABVALUE_PTR_INIT(&fields[6]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "jstype"), UPB_TABVALUE_PTR_INIT(&fields[39]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[12]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[10]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "extension"), UPB_TABVALUE_PTR_INIT(&fields[23]), NULL},
   {UPB_TABKEY_STR("\017", "\000", "\000", "\000", "weak_dependency"), UPB_TABVALUE_PTR_INIT(&fields[104]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[49]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[54]), NULL},
   {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "service"), UPB_TABVALUE_PTR_INIT(&fields[85]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "source_code_info"), UPB_TABVALUE_PTR_INIT(&fields[86]), NULL},
@@ -5276,8 +5720,8 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "dependency"), UPB_TABVALUE_PTR_INIT(&fields[8]), NULL},
   {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "message_type"), UPB_TABVALUE_PTR_INIT(&fields[47]), NULL},
   {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "package"), UPB_TABVALUE_PTR_INIT(&fields[76]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[72]), &strentries[86]},
-  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[19]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[69]), &strentries[86]},
+  {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "enum_type"), UPB_TABVALUE_PTR_INIT(&fields[20]), NULL},
   {UPB_TABKEY_STR("\021", "\000", "\000", "\000", "public_dependency"), UPB_TABVALUE_PTR_INIT(&fields[80]), &strentries[85]},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "file"), UPB_TABVALUE_PTR_INIT(&fields[26]), NULL},
@@ -5299,7 +5743,7 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "java_outer_classname"), UPB_TABVALUE_PTR_INIT(&fields[34]), NULL},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[99]), NULL},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[95]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
@@ -5312,7 +5756,7 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\023", "\000", "\000", "\000", "py_generic_services"), UPB_TABVALUE_PTR_INIT(&fields[81]), NULL},
   {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "optimize_for"), UPB_TABVALUE_PTR_INIT(&fields[67]), NULL},
   {UPB_TABKEY_STR("\026", "\000", "\000", "\000", "java_string_check_utf8"), UPB_TABVALUE_PTR_INIT(&fields[36]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[15]), &strentries[119]},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[12]), &strentries[119]},
   {UPB_TABKEY_STR("\021", "\000", "\000", "\000", "objc_class_prefix"), UPB_TABVALUE_PTR_INIT(&fields[64]), NULL},
   {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "cc_enable_arenas"), UPB_TABVALUE_PTR_INIT(&fields[2]), NULL},
   {UPB_TABKEY_STR("\027", "\000", "\000", "\000", "message_set_wire_format"), UPB_TABVALUE_PTR_INIT(&fields[46]), &strentries[128]},
@@ -5320,31 +5764,31 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[96]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[14]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[9]), NULL},
   {UPB_TABKEY_STR("\011", "\000", "\000", "\000", "map_entry"), UPB_TABVALUE_PTR_INIT(&fields[45]), NULL},
   {UPB_TABKEY_STR("\037", "\000", "\000", "\000", "no_standard_descriptor_accessor"), UPB_TABVALUE_PTR_INIT(&fields[61]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "client_streaming"), UPB_TABVALUE_PTR_INIT(&fields[4]), NULL},
   {UPB_TABKEY_STR("\020", "\000", "\000", "\000", "server_streaming"), UPB_TABVALUE_PTR_INIT(&fields[84]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[51]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[56]), NULL},
   {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "input_type"), UPB_TABVALUE_PTR_INIT(&fields[29]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\013", "\000", "\000", "\000", "output_type"), UPB_TABVALUE_PTR_INIT(&fields[75]), NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[68]), NULL},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[98]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[13]), NULL},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[70]), NULL},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[100]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[11]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[54]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[50]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[73]), &strentries[150]},
+  {UPB_TABKEY_STR("\007", "\000", "\000", "\000", "options"), UPB_TABVALUE_PTR_INIT(&fields[72]), &strentries[150]},
   {UPB_TABKEY_STR("\006", "\000", "\000", "\000", "method"), UPB_TABVALUE_PTR_INIT(&fields[48]), NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[55]), &strentries[149]},
-  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[95]), NULL},
-  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[11]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[57]), &strentries[149]},
+  {UPB_TABKEY_STR("\024", "\000", "\000", "\000", "uninterpreted_option"), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
+  {UPB_TABKEY_STR("\012", "\000", "\000", "\000", "deprecated"), UPB_TABVALUE_PTR_INIT(&fields[14]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
@@ -5362,7 +5806,7 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "double_value"), UPB_TABVALUE_PTR_INIT(&fields[16]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[57]), NULL},
+  {UPB_TABKEY_STR("\004", "\000", "\000", "\000", "name"), UPB_TABVALUE_PTR_INIT(&fields[51]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
@@ -5427,59 +5871,27 @@ static const upb_tabent strentries[268] = {
   {UPB_TABKEY_STR("\005", "\000", "\000", "\000", "SPEED"), UPB_TABVALUE_INT_INIT(1), &strentries[235]},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_STR("\014", "\000", "\000", "\000", "LITE_RUNTIME"), UPB_TABVALUE_INT_INIT(3), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\047", "\000", "\000", "\000", "google.protobuf.SourceCodeInfo.Location"), UPB_TABVALUE_PTR_INIT(&msgs[19]), NULL},
-  {UPB_TABKEY_STR("\043", "\000", "\000", "\000", "google.protobuf.UninterpretedOption"), UPB_TABVALUE_PTR_INIT(&msgs[20]), NULL},
-  {UPB_TABKEY_STR("\043", "\000", "\000", "\000", "google.protobuf.FileDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[9]), NULL},
-  {UPB_TABKEY_STR("\045", "\000", "\000", "\000", "google.protobuf.MethodDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[13]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\040", "\000", "\000", "\000", "google.protobuf.EnumValueOptions"), UPB_TABVALUE_PTR_INIT(&msgs[6]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_STR("\055", "\000", "\000", "\000", "google.protobuf.DescriptorProto.ReservedRange"), UPB_TABVALUE_PTR_INIT(&msgs[2]), NULL},
-  {UPB_TABKEY_STR("\037", "\000", "\000", "\000", "google.protobuf.DescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[0]), &strentries[248]},
-  {UPB_TABKEY_STR("\041", "\000", "\000", "\000", "google.protobuf.FileDescriptorSet"), UPB_TABVALUE_PTR_INIT(&msgs[10]), &strentries[267]},
-  {UPB_TABKEY_STR("\036", "\000", "\000", "\000", "google.protobuf.SourceCodeInfo"), UPB_TABVALUE_PTR_INIT(&msgs[18]), NULL},
-  {UPB_TABKEY_STR("\051", "\000", "\000", "\000", "google.protobuf.FieldDescriptorProto.Type"), UPB_TABVALUE_PTR_INIT(&enums[1]), NULL},
-  {UPB_TABKEY_STR("\056", "\000", "\000", "\000", "google.protobuf.DescriptorProto.ExtensionRange"), UPB_TABVALUE_PTR_INIT(&msgs[1]), NULL},
-  {UPB_TABKEY_STR("\044", "\000", "\000", "\000", "google.protobuf.OneofDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[15]), NULL},
-  {UPB_TABKEY_STR("\046", "\000", "\000", "\000", "google.protobuf.ServiceDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[16]), NULL},
-  {UPB_TABKEY_STR("\034", "\000", "\000", "\000", "google.protobuf.FieldOptions"), UPB_TABVALUE_PTR_INIT(&msgs[8]), NULL},
-  {UPB_TABKEY_STR("\033", "\000", "\000", "\000", "google.protobuf.FileOptions"), UPB_TABVALUE_PTR_INIT(&msgs[11]), NULL},
-  {UPB_TABKEY_STR("\043", "\000", "\000", "\000", "google.protobuf.EnumDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[3]), &strentries[265]},
-  {UPB_TABKEY_STR("\052", "\000", "\000", "\000", "google.protobuf.FieldDescriptorProto.Label"), UPB_TABVALUE_PTR_INIT(&enums[0]), NULL},
-  {UPB_TABKEY_STR("\050", "\000", "\000", "\000", "google.protobuf.FileOptions.OptimizeMode"), UPB_TABVALUE_PTR_INIT(&enums[4]), NULL},
-  {UPB_TABKEY_STR("\042", "\000", "\000", "\000", "google.protobuf.FieldOptions.CType"), UPB_TABVALUE_PTR_INIT(&enums[2]), &strentries[261]},
-  {UPB_TABKEY_STR("\043", "\000", "\000", "\000", "google.protobuf.FieldOptions.JSType"), UPB_TABVALUE_PTR_INIT(&enums[3]), NULL},
-  {UPB_TABKEY_STR("\033", "\000", "\000", "\000", "google.protobuf.EnumOptions"), UPB_TABVALUE_PTR_INIT(&msgs[4]), NULL},
-  {UPB_TABKEY_STR("\044", "\000", "\000", "\000", "google.protobuf.FieldDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[7]), NULL},
-  {UPB_TABKEY_STR("\050", "\000", "\000", "\000", "google.protobuf.EnumValueDescriptorProto"), UPB_TABVALUE_PTR_INIT(&msgs[5]), &strentries[258]},
-  {UPB_TABKEY_STR("\036", "\000", "\000", "\000", "google.protobuf.ServiceOptions"), UPB_TABVALUE_PTR_INIT(&msgs[17]), NULL},
-  {UPB_TABKEY_STR("\036", "\000", "\000", "\000", "google.protobuf.MessageOptions"), UPB_TABVALUE_PTR_INIT(&msgs[12]), NULL},
-  {UPB_TABKEY_STR("\035", "\000", "\000", "\000", "google.protobuf.MethodOptions"), UPB_TABVALUE_PTR_INIT(&msgs[14]), &strentries[253]},
-  {UPB_TABKEY_STR("\054", "\000", "\000", "\000", "google.protobuf.UninterpretedOption.NamePart"), UPB_TABVALUE_PTR_INIT(&msgs[21]), NULL},
 };
 
 static const upb_tabent intentries[18] = {
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[100]), NULL},
-  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
+  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[98]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[97]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[99]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
+  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[95]), NULL},
+  {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
   {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[96]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[13]), NULL},
+  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[11]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[98]), NULL},
+  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[100]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[11]), NULL},
+  {UPB_TABKEY_NUM(33), UPB_TABVALUE_PTR_INIT(&fields[14]), NULL},
   {UPB_TABKEY_NONE, UPB_TABVALUE_EMPTY_INIT, NULL},
-  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[95]), NULL},
+  {UPB_TABKEY_NUM(999), UPB_TABVALUE_PTR_INIT(&fields[101]), NULL},
 };
 
 static const upb_tabval arrays[184] = {
@@ -5487,48 +5899,48 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_PTR_INIT(&fields[52]),
   UPB_TABVALUE_PTR_INIT(&fields[25]),
   UPB_TABVALUE_PTR_INIT(&fields[60]),
-  UPB_TABVALUE_PTR_INIT(&fields[20]),
+  UPB_TABVALUE_PTR_INIT(&fields[19]),
   UPB_TABVALUE_PTR_INIT(&fields[24]),
   UPB_TABVALUE_PTR_INIT(&fields[22]),
-  UPB_TABVALUE_PTR_INIT(&fields[70]),
+  UPB_TABVALUE_PTR_INIT(&fields[68]),
   UPB_TABVALUE_PTR_INIT(&fields[65]),
   UPB_TABVALUE_PTR_INIT(&fields[83]),
   UPB_TABVALUE_PTR_INIT(&fields[82]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[88]),
+  UPB_TABVALUE_PTR_INIT(&fields[89]),
   UPB_TABVALUE_PTR_INIT(&fields[18]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[89]),
+  UPB_TABVALUE_PTR_INIT(&fields[88]),
   UPB_TABVALUE_PTR_INIT(&fields[17]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[53]),
+  UPB_TABVALUE_PTR_INIT(&fields[49]),
   UPB_TABVALUE_PTR_INIT(&fields[102]),
-  UPB_TABVALUE_PTR_INIT(&fields[69]),
+  UPB_TABVALUE_PTR_INIT(&fields[74]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[1]),
-  UPB_TABVALUE_PTR_INIT(&fields[10]),
+  UPB_TABVALUE_PTR_INIT(&fields[13]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[50]),
-  UPB_TABVALUE_PTR_INIT(&fields[63]),
-  UPB_TABVALUE_PTR_INIT(&fields[71]),
+  UPB_TABVALUE_PTR_INIT(&fields[53]),
+  UPB_TABVALUE_PTR_INIT(&fields[62]),
+  UPB_TABVALUE_PTR_INIT(&fields[73]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[9]),
+  UPB_TABVALUE_PTR_INIT(&fields[15]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[56]),
+  UPB_TABVALUE_PTR_INIT(&fields[55]),
   UPB_TABVALUE_PTR_INIT(&fields[21]),
-  UPB_TABVALUE_PTR_INIT(&fields[62]),
+  UPB_TABVALUE_PTR_INIT(&fields[63]),
   UPB_TABVALUE_PTR_INIT(&fields[40]),
   UPB_TABVALUE_PTR_INIT(&fields[93]),
   UPB_TABVALUE_PTR_INIT(&fields[94]),
   UPB_TABVALUE_PTR_INIT(&fields[7]),
-  UPB_TABVALUE_PTR_INIT(&fields[74]),
+  UPB_TABVALUE_PTR_INIT(&fields[71]),
   UPB_TABVALUE_PTR_INIT(&fields[66]),
   UPB_TABVALUE_PTR_INIT(&fields[38]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[6]),
   UPB_TABVALUE_PTR_INIT(&fields[77]),
-  UPB_TABVALUE_PTR_INIT(&fields[12]),
+  UPB_TABVALUE_PTR_INIT(&fields[10]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[41]),
   UPB_TABVALUE_PTR_INIT(&fields[39]),
@@ -5537,14 +5949,14 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[103]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[49]),
+  UPB_TABVALUE_PTR_INIT(&fields[54]),
   UPB_TABVALUE_PTR_INIT(&fields[76]),
   UPB_TABVALUE_PTR_INIT(&fields[8]),
   UPB_TABVALUE_PTR_INIT(&fields[47]),
-  UPB_TABVALUE_PTR_INIT(&fields[19]),
+  UPB_TABVALUE_PTR_INIT(&fields[20]),
   UPB_TABVALUE_PTR_INIT(&fields[85]),
   UPB_TABVALUE_PTR_INIT(&fields[23]),
-  UPB_TABVALUE_PTR_INIT(&fields[72]),
+  UPB_TABVALUE_PTR_INIT(&fields[69]),
   UPB_TABVALUE_PTR_INIT(&fields[86]),
   UPB_TABVALUE_PTR_INIT(&fields[80]),
   UPB_TABVALUE_PTR_INIT(&fields[104]),
@@ -5574,7 +5986,7 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_PTR_INIT(&fields[31]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[15]),
+  UPB_TABVALUE_PTR_INIT(&fields[12]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
@@ -5593,25 +6005,25 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[46]),
   UPB_TABVALUE_PTR_INIT(&fields[61]),
-  UPB_TABVALUE_PTR_INIT(&fields[14]),
+  UPB_TABVALUE_PTR_INIT(&fields[9]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[45]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[51]),
+  UPB_TABVALUE_PTR_INIT(&fields[56]),
   UPB_TABVALUE_PTR_INIT(&fields[29]),
   UPB_TABVALUE_PTR_INIT(&fields[75]),
-  UPB_TABVALUE_PTR_INIT(&fields[68]),
+  UPB_TABVALUE_PTR_INIT(&fields[70]),
   UPB_TABVALUE_PTR_INIT(&fields[4]),
   UPB_TABVALUE_PTR_INIT(&fields[84]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[54]),
+  UPB_TABVALUE_PTR_INIT(&fields[50]),
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[55]),
+  UPB_TABVALUE_PTR_INIT(&fields[57]),
   UPB_TABVALUE_PTR_INIT(&fields[48]),
-  UPB_TABVALUE_PTR_INIT(&fields[73]),
+  UPB_TABVALUE_PTR_INIT(&fields[72]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_PTR_INIT(&fields[44]),
@@ -5624,7 +6036,7 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_PTR_INIT(&fields[43]),
   UPB_TABVALUE_EMPTY_INIT,
   UPB_TABVALUE_EMPTY_INIT,
-  UPB_TABVALUE_PTR_INIT(&fields[57]),
+  UPB_TABVALUE_PTR_INIT(&fields[51]),
   UPB_TABVALUE_PTR_INIT(&fields[28]),
   UPB_TABVALUE_PTR_INIT(&fields[79]),
   UPB_TABVALUE_PTR_INIT(&fields[59]),
@@ -5669,17 +6081,8 @@ static const upb_tabval arrays[184] = {
   UPB_TABVALUE_PTR_INIT("LITE_RUNTIME"),
 };
 
-static const upb_symtab symtab = UPB_SYMTAB_INIT(UPB_STRTABLE_INIT(27, 31, UPB_CTYPE_PTR, 5, &strentries[236]), &reftables[264], &reftables[265]);
-
-const upb_symtab *upbdefs_google_protobuf_descriptor(const void *owner) {
-  upb_symtab_ref(&symtab, owner);
-  return &symtab;
-}
-
 #ifdef UPB_DEBUG_REFS
-static upb_inttable reftables[266] = {
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
-  UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
+static upb_inttable reftables[264] = {
   UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
   UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
   UPB_EMPTY_INTTABLE_INIT(UPB_CTYPE_PTR),
@@ -5947,6 +6350,45 @@ static upb_inttable reftables[266] = {
 };
 #endif
 
+static const upb_msgdef *refm(const upb_msgdef *m, const void *owner) {
+  upb_msgdef_ref(m, owner);
+  return m;
+}
+
+static const upb_enumdef *refe(const upb_enumdef *e, const void *owner) {
+  upb_enumdef_ref(e, owner);
+  return e;
+}
+
+/* Public API. */
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_get(const void *owner) { return refm(&msgs[0], owner); }
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(const void *owner) { return refm(&msgs[1], owner); }
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(const void *owner) { return refm(&msgs[2], owner); }
+const upb_msgdef *upbdefs_google_protobuf_EnumDescriptorProto_get(const void *owner) { return refm(&msgs[3], owner); }
+const upb_msgdef *upbdefs_google_protobuf_EnumOptions_get(const void *owner) { return refm(&msgs[4], owner); }
+const upb_msgdef *upbdefs_google_protobuf_EnumValueDescriptorProto_get(const void *owner) { return refm(&msgs[5], owner); }
+const upb_msgdef *upbdefs_google_protobuf_EnumValueOptions_get(const void *owner) { return refm(&msgs[6], owner); }
+const upb_msgdef *upbdefs_google_protobuf_FieldDescriptorProto_get(const void *owner) { return refm(&msgs[7], owner); }
+const upb_msgdef *upbdefs_google_protobuf_FieldOptions_get(const void *owner) { return refm(&msgs[8], owner); }
+const upb_msgdef *upbdefs_google_protobuf_FileDescriptorProto_get(const void *owner) { return refm(&msgs[9], owner); }
+const upb_msgdef *upbdefs_google_protobuf_FileDescriptorSet_get(const void *owner) { return refm(&msgs[10], owner); }
+const upb_msgdef *upbdefs_google_protobuf_FileOptions_get(const void *owner) { return refm(&msgs[11], owner); }
+const upb_msgdef *upbdefs_google_protobuf_MessageOptions_get(const void *owner) { return refm(&msgs[12], owner); }
+const upb_msgdef *upbdefs_google_protobuf_MethodDescriptorProto_get(const void *owner) { return refm(&msgs[13], owner); }
+const upb_msgdef *upbdefs_google_protobuf_MethodOptions_get(const void *owner) { return refm(&msgs[14], owner); }
+const upb_msgdef *upbdefs_google_protobuf_OneofDescriptorProto_get(const void *owner) { return refm(&msgs[15], owner); }
+const upb_msgdef *upbdefs_google_protobuf_ServiceDescriptorProto_get(const void *owner) { return refm(&msgs[16], owner); }
+const upb_msgdef *upbdefs_google_protobuf_ServiceOptions_get(const void *owner) { return refm(&msgs[17], owner); }
+const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_get(const void *owner) { return refm(&msgs[18], owner); }
+const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_Location_get(const void *owner) { return refm(&msgs[19], owner); }
+const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_get(const void *owner) { return refm(&msgs[20], owner); }
+const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_NamePart_get(const void *owner) { return refm(&msgs[21], owner); }
+
+const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Label_get(const void *owner) { return refe(&enums[0], owner); }
+const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Type_get(const void *owner) { return refe(&enums[1], owner); }
+const upb_enumdef *upbdefs_google_protobuf_FieldOptions_CType_get(const void *owner) { return refe(&enums[2], owner); }
+const upb_enumdef *upbdefs_google_protobuf_FieldOptions_JSType_get(const void *owner) { return refe(&enums[3], owner); }
+const upb_enumdef *upbdefs_google_protobuf_FileOptions_OptimizeMode_get(const void *owner) { return refe(&enums[4], owner); }
 /*
 ** XXX: The routines in this file that consume a string do not currently
 ** support having the string span buffers.  In the future, as upb_sink and
@@ -5965,15 +6407,6 @@ static bool upb_streq(const char *str, const char *buf, size_t n) {
   return strlen(str) == n && memcmp(str, buf, n) == 0;
 }
 
-/* upb_deflist is an internal-only dynamic array for storing a growing list of
- * upb_defs. */
-typedef struct {
-  upb_def **defs;
-  size_t len;
-  size_t size;
-  bool owned;
-} upb_deflist;
-
 /* We keep a stack of all the messages scopes we are currently in, as well as
  * the top-level file scope.  This is necessary to correctly qualify the
  * definitions that are contained inside.  "name" tracks the name of the
@@ -5999,13 +6432,11 @@ typedef struct {
 
 struct upb_descreader {
   upb_sink sink;
-  upb_deflist defs;
+  upb_inttable files;
+  upb_filedef *file;  /* The last file in files. */
   upb_descreader_frame stack[UPB_MAX_MESSAGE_NESTING];
   int stack_len;
 
-  bool primitives_have_presence;
-  int file_start;
-
   uint32_t number;
   char *name;
   bool saw_number;
@@ -6017,7 +6448,7 @@ struct upb_descreader {
 };
 
 static char *upb_strndup(const char *buf, size_t n) {
-  char *ret = malloc(n + 1);
+  char *ret = upb_gmalloc(n + 1);
   if (!ret) return NULL;
   memcpy(ret, buf, n);
   ret[n] = '\0';
@@ -6031,9 +6462,12 @@ static char *upb_strndup(const char *buf, size_t n) {
  * Caller owns a ref on the returned string. */
 static char *upb_join(const char *base, const char *name) {
   if (!base || strlen(base) == 0) {
-    return upb_strdup(name);
+    return upb_gstrdup(name);
   } else {
-    char *ret = malloc(strlen(base) + strlen(name) + 2);
+    char *ret = upb_gmalloc(strlen(base) + strlen(name) + 2);
+    if (!ret) {
+      return NULL;
+    }
     ret[0] = '\0';
     strcat(ret, base);
     strcat(ret, ".");
@@ -6042,57 +6476,21 @@ static char *upb_join(const char *base, const char *name) {
   }
 }
 
-
-/* upb_deflist ****************************************************************/
-
-void upb_deflist_init(upb_deflist *l) {
-  l->size = 0;
-  l->defs = NULL;
-  l->len = 0;
-  l->owned = true;
-}
-
-void upb_deflist_uninit(upb_deflist *l) {
-  size_t i;
-  if (l->owned)
-    for(i = 0; i < l->len; i++)
-      upb_def_unref(l->defs[i], l);
-  free(l->defs);
-}
-
-bool upb_deflist_push(upb_deflist *l, upb_def *d) {
-  if(++l->len >= l->size) {
-    size_t new_size = UPB_MAX(l->size, 4);
-    new_size *= 2;
-    l->defs = realloc(l->defs, new_size * sizeof(void *));
-    if (!l->defs) return false;
-    l->size = new_size;
-  }
-  l->defs[l->len - 1] = d;
-  return true;
-}
-
-void upb_deflist_donaterefs(upb_deflist *l, void *owner) {
-  size_t i;
-  assert(l->owned);
-  for (i = 0; i < l->len; i++)
-    upb_def_donateref(l->defs[i], l, owner);
-  l->owned = false;
-}
-
-static upb_def *upb_deflist_last(upb_deflist *l) {
-  return l->defs[l->len-1];
-}
-
 /* Qualify the defname for all defs starting with offset "start" with "str". */
-static void upb_deflist_qualify(upb_deflist *l, char *str, int32_t start) {
-  uint32_t i;
-  for (i = start; i < l->len; i++) {
-    upb_def *def = l->defs[i];
+static bool upb_descreader_qualify(upb_filedef *f, char *str, int32_t start) {
+  size_t i;
+  for (i = start; i < upb_filedef_defcount(f); i++) {
+    upb_def *def = upb_filedef_mutabledef(f, i);
     char *name = upb_join(str, upb_def_fullname(def));
+    if (!name) {
+      /* Need better logic here; at this point we've qualified some names but
+       * not others. */
+      return false;
+    }
     upb_def_setfullname(def, name, NULL);
-    free(name);
+    upb_gfree(name);
   }
+  return true;
 }
 
 
@@ -6103,92 +6501,144 @@ static upb_msgdef *upb_descreader_top(upb_descreader *r) {
   assert(r->stack_len > 1);
   index = r->stack[r->stack_len-1].start - 1;
   assert(index >= 0);
-  return upb_downcast_msgdef_mutable(r->defs.defs[index]);
+  return upb_downcast_msgdef_mutable(upb_filedef_mutabledef(r->file, index));
 }
 
 static upb_def *upb_descreader_last(upb_descreader *r) {
-  return upb_deflist_last(&r->defs);
+  return upb_filedef_mutabledef(r->file, upb_filedef_defcount(r->file) - 1);
 }
 
 /* Start/end handlers for FileDescriptorProto and DescriptorProto (the two
  * entities that have names and can contain sub-definitions. */
 void upb_descreader_startcontainer(upb_descreader *r) {
   upb_descreader_frame *f = &r->stack[r->stack_len++];
-  f->start = r->defs.len;
+  f->start = upb_filedef_defcount(r->file);
   f->name = NULL;
 }
 
-void upb_descreader_endcontainer(upb_descreader *r) {
+bool upb_descreader_endcontainer(upb_descreader *r) {
   upb_descreader_frame *f = &r->stack[--r->stack_len];
-  upb_deflist_qualify(&r->defs, f->name, f->start);
-  free(f->name);
+  if (!upb_descreader_qualify(r->file, f->name, f->start)) {
+    return false;
+  }
+  upb_gfree(f->name);
   f->name = NULL;
+  return true;
 }
 
 void upb_descreader_setscopename(upb_descreader *r, char *str) {
   upb_descreader_frame *f = &r->stack[r->stack_len-1];
-  free(f->name);
+  upb_gfree(f->name);
   f->name = str;
 }
 
-/* Handlers for google.protobuf.FileDescriptorProto. */
-static bool file_startmsg(void *closure, const void *hd) {
+/** Handlers for google.protobuf.FileDescriptorSet. ***************************/
+
+static void *fileset_startfile(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  UPB_UNUSED(hd);
+  r->file = upb_filedef_new(&r->files);
+  upb_inttable_push(&r->files, upb_value_ptr(r->file));
+  return r;
+}
+
+/** Handlers for google.protobuf.FileDescriptorProto. *************************/
+
+static bool file_start(void *closure, const void *hd) {
   upb_descreader *r = closure;
   UPB_UNUSED(hd);
   upb_descreader_startcontainer(r);
-  r->primitives_have_presence = true;
-  r->file_start = r->defs.len;
   return true;
 }
 
-static bool file_endmsg(void *closure, const void *hd, upb_status *status) {
+static bool file_end(void *closure, const void *hd, upb_status *status) {
   upb_descreader *r = closure;
   UPB_UNUSED(hd);
   UPB_UNUSED(status);
-  upb_descreader_endcontainer(r);
-  return true;
+  return upb_descreader_endcontainer(r);
+}
+
+static size_t file_onname(void *closure, const void *hd, const char *buf,
+                          size_t n, const upb_bufhandle *handle) {
+  upb_descreader *r = closure;
+  char *name;
+  bool ok;
+  UPB_UNUSED(hd);
+  UPB_UNUSED(handle);
+
+  name = upb_strndup(buf, n);
+  /* XXX: see comment at the top of the file. */
+  ok = upb_filedef_setname(r->file, name, NULL);
+  upb_gfree(name);
+  UPB_ASSERT_VAR(ok, ok);
+  return n;
 }
 
 static size_t file_onpackage(void *closure, const void *hd, const char *buf,
                              size_t n, const upb_bufhandle *handle) {
   upb_descreader *r = closure;
+  char *package;
+  bool ok;
   UPB_UNUSED(hd);
   UPB_UNUSED(handle);
+
+  package = upb_strndup(buf, n);
   /* XXX: see comment at the top of the file. */
-  upb_descreader_setscopename(r, upb_strndup(buf, n));
+  upb_descreader_setscopename(r, package);
+  ok = upb_filedef_setpackage(r->file, package, NULL);
+  UPB_ASSERT_VAR(ok, ok);
   return n;
 }
 
 static size_t file_onsyntax(void *closure, const void *hd, const char *buf,
                             size_t n, const upb_bufhandle *handle) {
   upb_descreader *r = closure;
+  bool ok;
   UPB_UNUSED(hd);
   UPB_UNUSED(handle);
   /* XXX: see comment at the top of the file. */
   if (upb_streq("proto2", buf, n)) {
-    /* Technically we could verify that proto3 hadn't previously been seen. */
+    ok = upb_filedef_setsyntax(r->file, UPB_SYNTAX_PROTO2, NULL);
   } else if (upb_streq("proto3", buf, n)) {
-    uint32_t i;
-    /* Update messages created before the syntax was read. */
-    for (i = r->file_start; i < r->defs.len; i++) {
-      upb_msgdef *m = upb_dyncast_msgdef_mutable(r->defs.defs[i]);
-      if (m) {
-        upb_msgdef_setprimitiveshavepresence(m, false);
-      }
-    }
-
-    /* Set a flag for any future messages that will be created. */
-    r->primitives_have_presence = false;
+    ok = upb_filedef_setsyntax(r->file, UPB_SYNTAX_PROTO3, NULL);
   } else {
-    /* Error: neither proto3 nor proto3.
-     * TODO(haberman): there should be a status object we can report this to. */
-    return 0;
+    ok = false;
   }
 
+  UPB_ASSERT_VAR(ok, ok);
   return n;
 }
 
-/* Handlers for google.protobuf.EnumValueDescriptorProto. */
+static void *file_startmsg(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  upb_msgdef *m = upb_msgdef_new(&m);
+  bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
+  UPB_UNUSED(hd);
+  UPB_ASSERT_VAR(ok, ok);
+  return r;
+}
+
+static void *file_startenum(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  upb_enumdef *e = upb_enumdef_new(&e);
+  bool ok = upb_filedef_addenum(r->file, e, &e, NULL);
+  UPB_UNUSED(hd);
+  UPB_ASSERT_VAR(ok, ok);
+  return r;
+}
+
+static void *file_startext(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  bool ok;
+  r->f = upb_fielddef_new(r);
+  ok = upb_filedef_addext(r->file, r->f, r, NULL);
+  UPB_UNUSED(hd);
+  UPB_ASSERT_VAR(ok, ok);
+  return r;
+}
+
+/** Handlers for google.protobuf.EnumValueDescriptorProto. *********************/
+
 static bool enumval_startmsg(void *closure, const void *hd) {
   upb_descreader *r = closure;
   UPB_UNUSED(hd);
@@ -6203,7 +6653,7 @@ static size_t enumval_onname(void *closure, const void *hd, const char *buf,
   UPB_UNUSED(hd);
   UPB_UNUSED(handle);
   /* XXX: see comment at the top of the file. */
-  free(r->name);
+  upb_gfree(r->name);
   r->name = upb_strndup(buf, n);
   r->saw_name = true;
   return n;
@@ -6228,20 +6678,12 @@ static bool enumval_endmsg(void *closure, const void *hd, upb_status *status) {
   }
   e = upb_downcast_enumdef_mutable(upb_descreader_last(r));
   upb_enumdef_addval(e, r->name, r->number, status);
-  free(r->name);
+  upb_gfree(r->name);
   r->name = NULL;
   return true;
 }
 
-
-/* Handlers for google.protobuf.EnumDescriptorProto. */
-static bool enum_startmsg(void *closure, const void *hd) {
-  upb_descreader *r = closure;
-  UPB_UNUSED(hd);
-  upb_deflist_push(&r->defs,
-                   upb_enumdef_upcast_mutable(upb_enumdef_new(&r->defs)));
-  return true;
-}
+/** Handlers for google.protobuf.EnumDescriptorProto. *************************/
 
 static bool enum_endmsg(void *closure, const void *hd, upb_status *status) {
   upb_descreader *r = closure;
@@ -6268,16 +6710,17 @@ static size_t enum_onname(void *closure, const void *hd, const char *buf,
   UPB_UNUSED(handle);
   /* XXX: see comment at the top of the file. */
   upb_def_setfullname(upb_descreader_last(r), fullname, NULL);
-  free(fullname);
+  upb_gfree(fullname);
   return n;
 }
 
-/* Handlers for google.protobuf.FieldDescriptorProto */
+/** Handlers for google.protobuf.FieldDescriptorProto *************************/
+
 static bool field_startmsg(void *closure, const void *hd) {
   upb_descreader *r = closure;
   UPB_UNUSED(hd);
-  r->f = upb_fielddef_new(&r->defs);
-  free(r->default_string);
+  assert(r->f);
+  upb_gfree(r->default_string);
   r->default_string = NULL;
 
   /* fielddefs default to packed, but descriptors default to non-packed. */
@@ -6419,9 +6862,10 @@ static bool field_onlabel(void *closure, const void *hd, int32_t val) {
 
 static bool field_onnumber(void *closure, const void *hd, int32_t val) {
   upb_descreader *r = closure;
-  bool ok = upb_fielddef_setnumber(r->f, val, NULL);
+  bool ok;
   UPB_UNUSED(hd);
 
+  ok = upb_fielddef_setnumber(r->f, val, NULL);
   UPB_ASSERT_VAR(ok, ok);
   return true;
 }
@@ -6435,7 +6879,7 @@ static size_t field_onname(void *closure, const void *hd, const char *buf,
 
   /* XXX: see comment at the top of the file. */
   upb_fielddef_setname(r->f, name, NULL);
-  free(name);
+  upb_gfree(name);
   return n;
 }
 
@@ -6448,7 +6892,7 @@ static size_t field_ontypename(void *closure, const void *hd, const char *buf,
 
   /* XXX: see comment at the top of the file. */
   upb_fielddef_setsubdefname(r->f, name, NULL);
-  free(name);
+  upb_gfree(name);
   return n;
 }
 
@@ -6461,7 +6905,7 @@ static size_t field_onextendee(void *closure, const void *hd, const char *buf,
 
   /* XXX: see comment at the top of the file. */
   upb_fielddef_setcontainingtypename(r->f, name, NULL);
-  free(name);
+  upb_gfree(name);
   return n;
 }
 
@@ -6474,25 +6918,22 @@ static size_t field_ondefaultval(void *closure, const void *hd, const char *buf,
   /* Have to convert from string to the correct type, but we might not know the
    * type yet, so we save it as a string until the end of the field.
    * XXX: see comment at the top of the file. */
-  free(r->default_string);
+  upb_gfree(r->default_string);
   r->default_string = upb_strndup(buf, n);
   return n;
 }
 
-/* Handlers for google.protobuf.DescriptorProto (representing a message). */
-static bool msg_startmsg(void *closure, const void *hd) {
+/** Handlers for google.protobuf.DescriptorProto ******************************/
+
+static bool msg_start(void *closure, const void *hd) {
   upb_descreader *r = closure;
-  upb_msgdef *m;
   UPB_UNUSED(hd);
 
-  m = upb_msgdef_new(&r->defs);
-  upb_msgdef_setprimitiveshavepresence(m, r->primitives_have_presence);
-  upb_deflist_push(&r->defs, upb_msgdef_upcast_mutable(m));
   upb_descreader_startcontainer(r);
   return true;
 }
 
-static bool msg_endmsg(void *closure, const void *hd, upb_status *status) {
+static bool msg_end(void *closure, const void *hd, upb_status *status) {
   upb_descreader *r = closure;
   upb_msgdef *m = upb_descreader_top(r);
   UPB_UNUSED(hd);
@@ -6501,12 +6942,11 @@ static bool msg_endmsg(void *closure, const void *hd, upb_status *status) {
     upb_status_seterrmsg(status, "Encountered message with no name.");
     return false;
   }
-  upb_descreader_endcontainer(r);
-  return true;
+  return upb_descreader_endcontainer(r);
 }
 
-static size_t msg_onname(void *closure, const void *hd, const char *buf,
-                         size_t n, const upb_bufhandle *handle) {
+static size_t msg_name(void *closure, const void *hd, const char *buf,
+                       size_t n, const upb_bufhandle *handle) {
   upb_descreader *r = closure;
   upb_msgdef *m = upb_descreader_top(r);
   /* XXX: see comment at the top of the file. */
@@ -6519,93 +6959,147 @@ static size_t msg_onname(void *closure, const void *hd, const char *buf,
   return n;
 }
 
-static bool msg_onendfield(void *closure, const void *hd) {
+static void *msg_startmsg(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  upb_msgdef *m = upb_msgdef_new(&m);
+  bool ok = upb_filedef_addmsg(r->file, m, &m, NULL);
+  UPB_UNUSED(hd);
+  UPB_ASSERT_VAR(ok, ok);
+  return r;
+}
+
+static void *msg_startext(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  upb_fielddef *f = upb_fielddef_new(&f);
+  bool ok = upb_filedef_addext(r->file, f, &f, NULL);
+  UPB_UNUSED(hd);
+  UPB_ASSERT_VAR(ok, ok);
+  return r;
+}
+
+static void *msg_startfield(void *closure, const void *hd) {
+  upb_descreader *r = closure;
+  r->f = upb_fielddef_new(&r->f);
+  /* We can't add the new field to the message until its name/number are
+   * filled in. */
+  UPB_UNUSED(hd);
+  return r;
+}
+
+static bool msg_endfield(void *closure, const void *hd) {
   upb_descreader *r = closure;
   upb_msgdef *m = upb_descreader_top(r);
   UPB_UNUSED(hd);
 
-  upb_msgdef_addfield(m, r->f, &r->defs, NULL);
+  upb_msgdef_addfield(m, r->f, &r->f, NULL);
   r->f = NULL;
   return true;
 }
 
-static bool pushextension(void *closure, const void *hd) {
+static bool msg_onmapentry(void *closure, const void *hd, bool mapentry) {
   upb_descreader *r = closure;
+  upb_msgdef *m = upb_descreader_top(r);
   UPB_UNUSED(hd);
 
-  assert(upb_fielddef_containingtypename(r->f));
-  upb_fielddef_setisextension(r->f, true);
-  upb_deflist_push(&r->defs, upb_fielddef_upcast_mutable(r->f));
+  upb_msgdef_setmapentry(m, mapentry);
   r->f = NULL;
   return true;
 }
 
-#define D(name) upbdefs_google_protobuf_ ## name(s)
+
+
+/** Code to register handlers *************************************************/
+
+#define F(msg, field) upbdefs_google_protobuf_ ## msg ## _f_ ## field(m)
 
 static void reghandlers(const void *closure, upb_handlers *h) {
-  const upb_symtab *s = closure;
   const upb_msgdef *m = upb_handlers_msgdef(h);
+  UPB_UNUSED(closure);
 
-  if (m == D(DescriptorProto)) {
-    upb_handlers_setstartmsg(h, &msg_startmsg, NULL);
-    upb_handlers_setendmsg(h, &msg_endmsg, NULL);
-    upb_handlers_setstring(h, D(DescriptorProto_name), &msg_onname, NULL);
-    upb_handlers_setendsubmsg(h, D(DescriptorProto_field), &msg_onendfield,
-                              NULL);
-    upb_handlers_setendsubmsg(h, D(DescriptorProto_extension), &pushextension,
-                              NULL);
-  } else if (m == D(FileDescriptorProto)) {
-    upb_handlers_setstartmsg(h, &file_startmsg, NULL);
-    upb_handlers_setendmsg(h, &file_endmsg, NULL);
-    upb_handlers_setstring(h, D(FileDescriptorProto_package), &file_onpackage,
+  if (upbdefs_google_protobuf_FileDescriptorSet_is(m)) {
+    upb_handlers_setstartsubmsg(h, F(FileDescriptorSet, file),
+                                &fileset_startfile, NULL);
+  } else if (upbdefs_google_protobuf_DescriptorProto_is(m)) {
+    upb_handlers_setstartmsg(h, &msg_start, NULL);
+    upb_handlers_setendmsg(h, &msg_end, NULL);
+    upb_handlers_setstring(h, F(DescriptorProto, name), &msg_name, NULL);
+    upb_handlers_setstartsubmsg(h, F(DescriptorProto, extension), &msg_startext,
+                                NULL);
+    upb_handlers_setstartsubmsg(h, F(DescriptorProto, nested_type),
+                                &msg_startmsg, NULL);
+    upb_handlers_setstartsubmsg(h, F(DescriptorProto, field),
+                                &msg_startfield, NULL);
+    upb_handlers_setendsubmsg(h, F(DescriptorProto, field),
+                              &msg_endfield, NULL);
+    upb_handlers_setstartsubmsg(h, F(DescriptorProto, enum_type),
+                                &file_startenum, NULL);
+  } else if (upbdefs_google_protobuf_FileDescriptorProto_is(m)) {
+    upb_handlers_setstartmsg(h, &file_start, NULL);
+    upb_handlers_setendmsg(h, &file_end, NULL);
+    upb_handlers_setstring(h, F(FileDescriptorProto, name), &file_onname,
                            NULL);
-    upb_handlers_setstring(h, D(FileDescriptorProto_syntax), &file_onsyntax,
+    upb_handlers_setstring(h, F(FileDescriptorProto, package), &file_onpackage,
                            NULL);
-    upb_handlers_setendsubmsg(h, D(FileDescriptorProto_extension), &pushextension,
-                              NULL);
-  } else if (m == D(EnumValueDescriptorProto)) {
+    upb_handlers_setstring(h, F(FileDescriptorProto, syntax), &file_onsyntax,
+                           NULL);
+    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, message_type),
+                                &file_startmsg, NULL);
+    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, enum_type),
+                                &file_startenum, NULL);
+    upb_handlers_setstartsubmsg(h, F(FileDescriptorProto, extension),
+                                &file_startext, NULL);
+  } else if (upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)) {
     upb_handlers_setstartmsg(h, &enumval_startmsg, NULL);
     upb_handlers_setendmsg(h, &enumval_endmsg, NULL);
-    upb_handlers_setstring(h, D(EnumValueDescriptorProto_name), &enumval_onname, NULL);
-    upb_handlers_setint32(h, D(EnumValueDescriptorProto_number), &enumval_onnumber,
+    upb_handlers_setstring(h, F(EnumValueDescriptorProto, name), &enumval_onname, NULL);
+    upb_handlers_setint32(h, F(EnumValueDescriptorProto, number), &enumval_onnumber,
                           NULL);
-  } else if (m == D(EnumDescriptorProto)) {
-    upb_handlers_setstartmsg(h, &enum_startmsg, NULL);
+  } else if (upbdefs_google_protobuf_EnumDescriptorProto_is(m)) {
     upb_handlers_setendmsg(h, &enum_endmsg, NULL);
-    upb_handlers_setstring(h, D(EnumDescriptorProto_name), &enum_onname, NULL);
-  } else if (m == D(FieldDescriptorProto)) {
+    upb_handlers_setstring(h, F(EnumDescriptorProto, name), &enum_onname, NULL);
+  } else if (upbdefs_google_protobuf_FieldDescriptorProto_is(m)) {
     upb_handlers_setstartmsg(h, &field_startmsg, NULL);
     upb_handlers_setendmsg(h, &field_endmsg, NULL);
-    upb_handlers_setint32(h, D(FieldDescriptorProto_type), &field_ontype,
+    upb_handlers_setint32(h, F(FieldDescriptorProto, type), &field_ontype,
                           NULL);
-    upb_handlers_setint32(h, D(FieldDescriptorProto_label), &field_onlabel,
+    upb_handlers_setint32(h, F(FieldDescriptorProto, label), &field_onlabel,
                           NULL);
-    upb_handlers_setint32(h, D(FieldDescriptorProto_number), &field_onnumber,
+    upb_handlers_setint32(h, F(FieldDescriptorProto, number), &field_onnumber,
                           NULL);
-    upb_handlers_setstring(h, D(FieldDescriptorProto_name), &field_onname,
+    upb_handlers_setstring(h, F(FieldDescriptorProto, name), &field_onname,
                            NULL);
-    upb_handlers_setstring(h, D(FieldDescriptorProto_type_name),
+    upb_handlers_setstring(h, F(FieldDescriptorProto, type_name),
                            &field_ontypename, NULL);
-    upb_handlers_setstring(h, D(FieldDescriptorProto_extendee),
+    upb_handlers_setstring(h, F(FieldDescriptorProto, extendee),
                            &field_onextendee, NULL);
-    upb_handlers_setstring(h, D(FieldDescriptorProto_default_value),
+    upb_handlers_setstring(h, F(FieldDescriptorProto, default_value),
                            &field_ondefaultval, NULL);
-  } else if (m == D(FieldOptions)) {
-    upb_handlers_setbool(h, D(FieldOptions_lazy), &field_onlazy, NULL);
-    upb_handlers_setbool(h, D(FieldOptions_packed), &field_onpacked, NULL);
+  } else if (upbdefs_google_protobuf_FieldOptions_is(m)) {
+    upb_handlers_setbool(h, F(FieldOptions, lazy), &field_onlazy, NULL);
+    upb_handlers_setbool(h, F(FieldOptions, packed), &field_onpacked, NULL);
+  } else if (upbdefs_google_protobuf_MessageOptions_is(m)) {
+    upb_handlers_setbool(h, F(MessageOptions, map_entry), &msg_onmapentry, NULL);
   }
+
+  assert(upb_ok(upb_handlers_status(h)));
 }
 
-#undef D
+#undef F
 
 void descreader_cleanup(void *_r) {
   upb_descreader *r = _r;
-  free(r->name);
-  upb_deflist_uninit(&r->defs);
-  free(r->default_string);
+  size_t i;
+
+  for (i = 0; i < upb_descreader_filecount(r); i++) {
+    upb_filedef_unref(upb_descreader_file(r, i), &r->files);
+  }
+
+  upb_gfree(r->name);
+  upb_inttable_uninit(&r->files);
+  upb_gfree(r->default_string);
   while (r->stack_len > 0) {
     upb_descreader_frame *f = &r->stack[--r->stack_len];
-    free(f->name);
+    upb_gfree(f->name);
   }
 }
 
@@ -6618,7 +7112,7 @@ upb_descreader *upb_descreader_create(upb_env *e, const upb_handlers *h) {
     return NULL;
   }
 
-  upb_deflist_init(&r->defs);
+  upb_inttable_init(&r->files, UPB_CTYPE_PTR);
   upb_sink_reset(upb_descreader_input(r), h, r);
   r->stack_len = 0;
   r->name = NULL;
@@ -6627,10 +7121,17 @@ upb_descreader *upb_descreader_create(upb_env *e, const upb_handlers *h) {
   return r;
 }
 
-upb_def **upb_descreader_getdefs(upb_descreader *r, void *owner, int *n) {
-  *n = r->defs.len;
-  upb_deflist_donaterefs(&r->defs, owner);
-  return r->defs.defs;
+size_t upb_descreader_filecount(const upb_descreader *r) {
+  return upb_inttable_count(&r->files);
+}
+
+upb_filedef *upb_descreader_file(const upb_descreader *r, size_t i) {
+  upb_value v;
+  if (upb_inttable_lookup(&r->files, i, &v)) {
+    return upb_value_getptr(v);
+  } else {
+    return NULL;
+  }
 }
 
 upb_sink *upb_descreader_input(upb_descreader *r) {
@@ -6638,10 +7139,9 @@ upb_sink *upb_descreader_input(upb_descreader *r) {
 }
 
 const upb_handlers *upb_descreader_newhandlers(const void *owner) {
-  const upb_symtab *s = upbdefs_google_protobuf_descriptor(&s);
-  const upb_handlers *h = upb_handlers_newfrozen(
-      upbdefs_google_protobuf_FileDescriptorSet(s), owner, reghandlers, s);
-  upb_symtab_unref(s, &s);
+  const upb_msgdef *m = upbdefs_google_protobuf_FileDescriptorSet_get(&m);
+  const upb_handlers *h = upb_handlers_newfrozen(m, owner, reghandlers, NULL);
+  upb_msgdef_unref(m, &m);
   return h;
 }
 /*
@@ -6675,8 +7175,8 @@ static void freegroup(upb_refcounted *r) {
 #ifdef UPB_USE_JIT_X64
   upb_pbdecoder_freejit(g);
 #endif
-  free(g->bytecode);
-  free(g);
+  upb_gfree(g->bytecode);
+  upb_gfree(g);
 }
 
 static void visitgroup(const upb_refcounted *r, upb_refcounted_visit *visit,
@@ -6691,7 +7191,7 @@ static void visitgroup(const upb_refcounted *r, upb_refcounted_visit *visit,
 }
 
 mgroup *newgroup(const void *owner) {
-  mgroup *g = malloc(sizeof(*g));
+  mgroup *g = upb_gmalloc(sizeof(*g));
   static const struct upb_refcounted_vtbl vtbl = {visitgroup, freegroup};
   upb_refcounted_init(mgroup_upcast_mutable(g), &vtbl, owner);
   upb_inttable_init(&g->methods, UPB_CTYPE_PTR);
@@ -6711,7 +7211,7 @@ static void freemethod(upb_refcounted *r) {
   }
 
   upb_inttable_uninit(&method->dispatch);
-  free(method);
+  upb_gfree(method);
 }
 
 static void visitmethod(const upb_refcounted *r, upb_refcounted_visit *visit,
@@ -6723,7 +7223,7 @@ static void visitmethod(const upb_refcounted *r, upb_refcounted_visit *visit,
 static upb_pbdecodermethod *newmethod(const upb_handlers *dest_handlers,
                                       mgroup *group) {
   static const struct upb_refcounted_vtbl vtbl = {visitmethod, freemethod};
-  upb_pbdecodermethod *ret = malloc(sizeof(*ret));
+  upb_pbdecodermethod *ret = upb_gmalloc(sizeof(*ret));
   upb_refcounted_init(upb_pbdecodermethod_upcast_mutable(ret), &vtbl, &ret);
   upb_byteshandler_init(&ret->input_handler_);
 
@@ -6786,7 +7286,7 @@ typedef struct {
 } compiler;
 
 static compiler *newcompiler(mgroup *group, bool lazy) {
-  compiler *ret = malloc(sizeof(*ret));
+  compiler *ret = upb_gmalloc(sizeof(*ret));
   int i;
 
   ret->group = group;
@@ -6799,7 +7299,7 @@ static compiler *newcompiler(mgroup *group, bool lazy) {
 }
 
 static void freecompiler(compiler *c) {
-  free(c);
+  upb_gfree(c);
 }
 
 const size_t ptr_words = sizeof(void*) / sizeof(uint32_t);
@@ -6903,7 +7403,8 @@ static void put32(compiler *c, uint32_t v) {
     size_t oldsize = g->bytecode_end - g->bytecode;
     size_t newsize = UPB_MAX(oldsize * 2, 64);
     /* TODO(haberman): handle OOM. */
-    g->bytecode = realloc(g->bytecode, newsize * sizeof(uint32_t));
+    g->bytecode = upb_grealloc(g->bytecode, oldsize * sizeof(uint32_t),
+                                            newsize * sizeof(uint32_t));
     g->bytecode_end = g->bytecode + newsize;
     c->pc = g->bytecode + ofs;
   }
@@ -8768,7 +9269,6 @@ bool upb_pbdecoder_setmaxnesting(upb_pbdecoder *d, size_t max) {
 */
 
 
-#include <stdlib.h>
 
 /* The output buffer is divided into segments; a segment is a string of data
  * that is "ready to go" -- it does not need any varint lengths inserted into
@@ -9013,12 +9513,12 @@ static void new_tag(upb_handlers *h, const upb_fielddef *f, upb_wiretype_t wt,
                     upb_handlerattr *attr) {
   uint32_t n = upb_fielddef_number(f);
 
-  tag_t *tag = malloc(sizeof(tag_t));
+  tag_t *tag = upb_gmalloc(sizeof(tag_t));
   tag->bytes = upb_vencode64((n << 3) | wt, tag->tag);
 
   upb_handlerattr_init(attr);
   upb_handlerattr_sethandlerdata(attr, tag);
-  upb_handlers_addcleanup(h, tag, free);
+  upb_handlers_addcleanup(h, tag, upb_gfree);
 }
 
 static bool encode_tag(upb_pb_encoder *e, const tag_t *tag) {
@@ -9277,12 +9777,9 @@ upb_pb_encoder *upb_pb_encoder_create(upb_env *env, const upb_handlers *h,
 upb_sink *upb_pb_encoder_input(upb_pb_encoder *e) { return &e->input_; }
 
 
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 
-upb_def **upb_load_defs_from_descriptor(const char *str, size_t len, int *n,
-                                        void *owner, upb_status *status) {
+upb_filedef **upb_loaddescriptor(const char *buf, size_t n, const void *owner,
+                                 upb_status *status) {
   /* Create handlers. */
   const upb_pbdecodermethod *decoder_m;
   const upb_handlers *reader_h = upb_descreader_newhandlers(&reader_h);
@@ -9291,8 +9788,8 @@ upb_def **upb_load_defs_from_descriptor(const char *str, size_t len, int *n,
   upb_pbdecoder *decoder;
   upb_descreader *reader;
   bool ok;
-  upb_def **ret = NULL;
-  upb_def **defs;
+  size_t i;
+  upb_filedef **ret = NULL;
 
   upb_pbdecodermethodopts_init(&opts, reader_h);
   decoder_m = upb_pbdecodermethod_new(&opts, &decoder_m);
@@ -9304,12 +9801,24 @@ upb_def **upb_load_defs_from_descriptor(const char *str, size_t len, int *n,
   decoder = upb_pbdecoder_create(&env, decoder_m, upb_descreader_input(reader));
 
   /* Push input data. */
-  ok = upb_bufsrc_putbuf(str, len, upb_pbdecoder_input(decoder));
+  ok = upb_bufsrc_putbuf(buf, n, upb_pbdecoder_input(decoder));
+
+  if (!ok) {
+    goto cleanup;
+  }
+
+  ret = upb_gmalloc(sizeof (*ret) * (upb_descreader_filecount(reader) + 1));
+
+  if (!ret) {
+    goto cleanup;
+  }
+
+  for (i = 0; i < upb_descreader_filecount(reader); i++) {
+    ret[i] = upb_descreader_file(reader, i);
+    upb_filedef_ref(ret[i], owner);
+  }
 
-  if (!ok) goto cleanup;
-  defs = upb_descreader_getdefs(reader, owner, n);
-  ret = malloc(sizeof(upb_def*) * (*n));
-  memcpy(ret, defs, sizeof(upb_def*) * (*n));
+  ret[i] = NULL;
 
 cleanup:
   upb_env_uninit(&env);
@@ -9317,51 +9826,6 @@ cleanup:
   upb_pbdecodermethod_unref(decoder_m, &decoder_m);
   return ret;
 }
-
-bool upb_load_descriptor_into_symtab(upb_symtab *s, const char *str, size_t len,
-                                     upb_status *status) {
-  int n;
-  bool success;
-  upb_def **defs = upb_load_defs_from_descriptor(str, len, &n, &defs, status);
-  if (!defs) return false;
-  success = upb_symtab_add(s, defs, n, &defs, status);
-  free(defs);
-  return success;
-}
-
-char *upb_readfile(const char *filename, size_t *len) {
-  long size;
-  char *buf;
-  FILE *f = fopen(filename, "rb");
-  if(!f) return NULL;
-  if(fseek(f, 0, SEEK_END) != 0) goto error;
-  size = ftell(f);
-  if(size < 0) goto error;
-  if(fseek(f, 0, SEEK_SET) != 0) goto error;
-  buf = malloc(size + 1);
-  if(size && fread(buf, size, 1, f) != 1) goto error;
-  fclose(f);
-  if (len) *len = size;
-  return buf;
-
-error:
-  fclose(f);
-  return NULL;
-}
-
-bool upb_load_descriptor_file_into_symtab(upb_symtab *symtab, const char *fname,
-                                          upb_status *status) {
-  size_t len;
-  bool success;
-  char *data = upb_readfile(fname, &len);
-  if (!data) {
-    if (status) upb_status_seterrf(status, "Couldn't read file: %s", fname);
-    return false;
-  }
-  success = upb_load_descriptor_into_symtab(symtab, data, len, status);
-  free(data);
-  return success;
-}
 /*
  * upb::pb::TextPrinter
  *
@@ -9375,7 +9839,6 @@ bool upb_load_descriptor_file_into_symtab(upb_symtab *symtab, const char *fname,
 #include <inttypes.h>
 #include <stdarg.h>
 #include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
 
 
@@ -9471,14 +9934,14 @@ bool putf(upb_textprinter *p, const char *fmt, ...) {
   va_end(args_copy);
 
   /* + 1 for NULL terminator (vsprintf() requires it even if we don't). */
-  str = malloc(len + 1);
+  str = upb_gmalloc(len + 1);
   if (!str) return false;
   written = vsprintf(str, fmt, args);
   va_end(args);
   UPB_ASSERT_VAR(written, written == len);
 
   ok = upb_bytessink_putbuf(p->output_, p->subc, str, len, NULL);
-  free(str);
+  upb_gfree(str);
   return ok;
 }
 
@@ -9847,12 +10310,11 @@ upb_decoderet upb_vdecode_max8_wright(upb_decoderet r) {
 ** - handling of keys/escape-sequences/etc that span input buffers.
 */
 
-#include <stdio.h>
-#include <stdint.h>
 #include <assert.h>
-#include <string.h>
-#include <stdlib.h>
 #include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
 
 
 #define UPB_JSON_MAX_DEPTH 64
@@ -10975,11 +11437,11 @@ static void end_object(upb_json_parser *p) {
  * final state once, when the closing '"' is seen. */
 
 
-#line 1246 "upb/json/parser.rl"
+#line 1245 "upb/json/parser.rl"
 
 
 
-#line 1158 "upb/json/parser.c"
+#line 1157 "upb/json/parser.c"
 static const char _json_actions[] = {
 	0, 1, 0, 1, 2, 1, 3, 1, 
 	5, 1, 6, 1, 7, 1, 8, 1, 
@@ -11128,7 +11590,7 @@ static const int json_en_value_machine = 27;
 static const int json_en_main = 1;
 
 
-#line 1249 "upb/json/parser.rl"
+#line 1248 "upb/json/parser.rl"
 
 size_t parse(void *closure, const void *hd, const char *buf, size_t size,
              const upb_bufhandle *handle) {
@@ -11150,7 +11612,7 @@ size_t parse(void *closure, const void *hd, const char *buf, size_t size,
   capture_resume(parser, buf);
 
   
-#line 1329 "upb/json/parser.c"
+#line 1328 "upb/json/parser.c"
 	{
 	int _klen;
 	unsigned int _trans;
@@ -11225,118 +11687,118 @@ _match:
 		switch ( *_acts++ )
 		{
 	case 0:
-#line 1161 "upb/json/parser.rl"
+#line 1160 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 1:
-#line 1162 "upb/json/parser.rl"
+#line 1161 "upb/json/parser.rl"
 	{ p--; {stack[top++] = cs; cs = 10; goto _again;} }
 	break;
 	case 2:
-#line 1166 "upb/json/parser.rl"
+#line 1165 "upb/json/parser.rl"
 	{ start_text(parser, p); }
 	break;
 	case 3:
-#line 1167 "upb/json/parser.rl"
+#line 1166 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_text(parser, p)); }
 	break;
 	case 4:
-#line 1173 "upb/json/parser.rl"
+#line 1172 "upb/json/parser.rl"
 	{ start_hex(parser); }
 	break;
 	case 5:
-#line 1174 "upb/json/parser.rl"
+#line 1173 "upb/json/parser.rl"
 	{ hexdigit(parser, p); }
 	break;
 	case 6:
-#line 1175 "upb/json/parser.rl"
+#line 1174 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_hex(parser)); }
 	break;
 	case 7:
-#line 1181 "upb/json/parser.rl"
+#line 1180 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(escape(parser, p)); }
 	break;
 	case 8:
-#line 1187 "upb/json/parser.rl"
+#line 1186 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
 	case 9:
-#line 1190 "upb/json/parser.rl"
+#line 1189 "upb/json/parser.rl"
 	{ {stack[top++] = cs; cs = 19; goto _again;} }
 	break;
 	case 10:
-#line 1192 "upb/json/parser.rl"
+#line 1191 "upb/json/parser.rl"
 	{ p--; {stack[top++] = cs; cs = 27; goto _again;} }
 	break;
 	case 11:
-#line 1197 "upb/json/parser.rl"
+#line 1196 "upb/json/parser.rl"
 	{ start_member(parser); }
 	break;
 	case 12:
-#line 1198 "upb/json/parser.rl"
+#line 1197 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_membername(parser)); }
 	break;
 	case 13:
-#line 1201 "upb/json/parser.rl"
+#line 1200 "upb/json/parser.rl"
 	{ end_member(parser); }
 	break;
 	case 14:
-#line 1207 "upb/json/parser.rl"
+#line 1206 "upb/json/parser.rl"
 	{ start_object(parser); }
 	break;
 	case 15:
-#line 1210 "upb/json/parser.rl"
+#line 1209 "upb/json/parser.rl"
 	{ end_object(parser); }
 	break;
 	case 16:
-#line 1216 "upb/json/parser.rl"
+#line 1215 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_array(parser)); }
 	break;
 	case 17:
-#line 1220 "upb/json/parser.rl"
+#line 1219 "upb/json/parser.rl"
 	{ end_array(parser); }
 	break;
 	case 18:
-#line 1225 "upb/json/parser.rl"
+#line 1224 "upb/json/parser.rl"
 	{ start_number(parser, p); }
 	break;
 	case 19:
-#line 1226 "upb/json/parser.rl"
+#line 1225 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_number(parser, p)); }
 	break;
 	case 20:
-#line 1228 "upb/json/parser.rl"
+#line 1227 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_stringval(parser)); }
 	break;
 	case 21:
-#line 1229 "upb/json/parser.rl"
+#line 1228 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(end_stringval(parser)); }
 	break;
 	case 22:
-#line 1231 "upb/json/parser.rl"
+#line 1230 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(parser_putbool(parser, true)); }
 	break;
 	case 23:
-#line 1233 "upb/json/parser.rl"
+#line 1232 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(parser_putbool(parser, false)); }
 	break;
 	case 24:
-#line 1235 "upb/json/parser.rl"
+#line 1234 "upb/json/parser.rl"
 	{ /* null value */ }
 	break;
 	case 25:
-#line 1237 "upb/json/parser.rl"
+#line 1236 "upb/json/parser.rl"
 	{ CHECK_RETURN_TOP(start_subobject(parser)); }
 	break;
 	case 26:
-#line 1238 "upb/json/parser.rl"
+#line 1237 "upb/json/parser.rl"
 	{ end_subobject(parser); }
 	break;
 	case 27:
-#line 1243 "upb/json/parser.rl"
+#line 1242 "upb/json/parser.rl"
 	{ p--; {cs = stack[--top]; goto _again;} }
 	break;
-#line 1515 "upb/json/parser.c"
+#line 1514 "upb/json/parser.c"
 		}
 	}
 
@@ -11349,10 +11811,10 @@ _again:
 	_out: {}
 	}
 
-#line 1270 "upb/json/parser.rl"
+#line 1269 "upb/json/parser.rl"
 
   if (p != pe) {
-    upb_status_seterrf(&parser->status, "Parse error at %s\n", p);
+    upb_status_seterrf(&parser->status, "Parse error at '%.*s'\n", pe - p, p);
     upb_env_reporterror(parser->env, &parser->status);
   } else {
     capture_suspend(parser, &p);
@@ -11390,13 +11852,13 @@ static void json_parser_reset(upb_json_parser *p) {
 
   /* Emit Ragel initialization of the parser. */
   
-#line 1569 "upb/json/parser.c"
+#line 1568 "upb/json/parser.c"
 	{
 	cs = json_start;
 	top = 0;
 	}
 
-#line 1310 "upb/json/parser.rl"
+#line 1309 "upb/json/parser.rl"
   p->current_state = cs;
   p->parser_top = top;
   accumulate_clear(p);
@@ -11422,12 +11884,12 @@ static void free_json_parsermethod(upb_refcounted *r) {
     upb_value val = upb_inttable_iter_value(&i);
     upb_strtable *t = upb_value_getptr(val);
     upb_strtable_uninit(t);
-    free(t);
+    upb_gfree(t);
   }
 
   upb_inttable_uninit(&method->name_tables);
 
-  free(r);
+  upb_gfree(r);
 }
 
 static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
@@ -11444,7 +11906,7 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
   }
 
   /* TODO(haberman): handle malloc failure. */
-  t = malloc(sizeof(*t));
+  t = upb_gmalloc(sizeof(*t));
   upb_strtable_init(t, UPB_CTYPE_CONSTPTR);
   upb_inttable_insertptr(&m->name_tables, md, upb_value_ptr(t));
 
@@ -11452,20 +11914,31 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
       !upb_msg_field_done(&i);
       upb_msg_field_next(&i)) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
+
+    /* Add an entry for the JSON name. */
     size_t field_len = upb_fielddef_getjsonname(f, buf, len);
     if (field_len > len) {
-      buf = realloc(buf, field_len);
+      size_t len2;
+      buf = upb_grealloc(buf, 0, field_len);
       len = field_len;
-      upb_fielddef_getjsonname(f, buf, len);
+      len2 = upb_fielddef_getjsonname(f, buf, len);
+      UPB_ASSERT_VAR(len2, len == len2);
     }
     upb_strtable_insert(t, buf, upb_value_constptr(f));
 
+    if (strcmp(buf, upb_fielddef_name(f)) != 0) {
+      /* Since the JSON name is different from the regular field name, add an
+       * entry for the raw name (compliant proto3 JSON parsers must accept
+       * both). */
+      upb_strtable_insert(t, upb_fielddef_name(f), upb_value_constptr(f));
+    }
+
     if (upb_fielddef_issubmsg(f)) {
       add_jsonname_table(m, upb_fielddef_msgsubdef(f));
     }
   }
 
-  free(buf);
+  upb_gfree(buf);
 }
 
 /* Public API *****************************************************************/
@@ -11505,7 +11978,7 @@ upb_json_parsermethod *upb_json_parsermethod_new(const upb_msgdef* md,
                                                  const void* owner) {
   static const struct upb_refcounted_vtbl vtbl = {visit_json_parsermethod,
                                                   free_json_parsermethod};
-  upb_json_parsermethod *ret = malloc(sizeof(*ret));
+  upb_json_parsermethod *ret = upb_gmalloc(sizeof(*ret));
   upb_refcounted_init(upb_json_parsermethod_upcast_mutable(ret), &vtbl, owner);
 
   ret->msg = md;
@@ -11532,8 +12005,6 @@ const upb_byteshandler *upb_json_parsermethod_inputhandler(
 */
 
 
-#include <stdlib.h>
-#include <stdio.h>
 #include <string.h>
 #include <stdint.h>
 
@@ -11566,20 +12037,26 @@ typedef struct {
 
 void freestrpc(void *ptr) {
   strpc *pc = ptr;
-  free(pc->ptr);
-  free(pc);
+  upb_gfree(pc->ptr);
+  upb_gfree(pc);
 }
 
 /* Convert fielddef name to JSON name and return as a string piece. */
-strpc *newstrpc(upb_handlers *h, const upb_fielddef *f) {
+strpc *newstrpc(upb_handlers *h, const upb_fielddef *f,
+                bool preserve_fieldnames) {
   /* TODO(haberman): handle malloc failure. */
-  strpc *ret = malloc(sizeof(*ret));
-  size_t len;
-  ret->len = upb_fielddef_getjsonname(f, NULL, 0);
-  ret->ptr = malloc(ret->len);
-  len = upb_fielddef_getjsonname(f, ret->ptr, ret->len);
-  UPB_ASSERT_VAR(len, len == ret->len);
-  ret->len--;  /* NULL */
+  strpc *ret = upb_gmalloc(sizeof(*ret));
+  if (preserve_fieldnames) {
+    ret->ptr = upb_gstrdup(upb_fielddef_name(f));
+    ret->len = strlen(ret->ptr);
+  } else {
+    size_t len;
+    ret->len = upb_fielddef_getjsonname(f, NULL, 0);
+    ret->ptr = upb_gmalloc(ret->len);
+    len = upb_fielddef_getjsonname(f, ret->ptr, ret->len);
+    UPB_ASSERT_VAR(len, len == ret->len);
+    ret->len--;  /* NULL */
+  }
 
   upb_handlers_addcleanup(h, ret, freestrpc);
   return ret;
@@ -12085,11 +12562,12 @@ static size_t mapkey_bytes(void *closure, const void *handler_data,
 
 static void set_enum_hd(upb_handlers *h,
                         const upb_fielddef *f,
+                        bool preserve_fieldnames,
                         upb_handlerattr *attr) {
-  EnumHandlerData *hd = malloc(sizeof(EnumHandlerData));
+  EnumHandlerData *hd = upb_gmalloc(sizeof(EnumHandlerData));
   hd->enumdef = (const upb_enumdef *)upb_fielddef_subdef(f);
-  hd->keyname = newstrpc(h, f);
-  upb_handlers_addcleanup(h, hd, free);
+  hd->keyname = newstrpc(h, f, preserve_fieldnames);
+  upb_handlers_addcleanup(h, hd, upb_gfree);
   upb_handlerattr_sethandlerdata(attr, hd);
 }
 
@@ -12105,7 +12583,8 @@ static void set_enum_hd(upb_handlers *h,
  * our sources that emit mapentry messages do so canonically (with one key
  * field, and then one value field), so this is not a pressing concern at the
  * moment. */
-void printer_sethandlers_mapentry(const void *closure, upb_handlers *h) {
+void printer_sethandlers_mapentry(const void *closure, bool preserve_fieldnames,
+                                  upb_handlers *h) {
   const upb_msgdef *md = upb_handlers_msgdef(h);
 
   /* A mapentry message is printed simply as '"key": value'. Rather than
@@ -12179,7 +12658,7 @@ void printer_sethandlers_mapentry(const void *closure, upb_handlers *h) {
       break;
     case UPB_TYPE_ENUM: {
       upb_handlerattr enum_attr = UPB_HANDLERATTR_INITIALIZER;
-      set_enum_hd(h, value_field, &enum_attr);
+      set_enum_hd(h, value_field, preserve_fieldnames, &enum_attr);
       upb_handlers_setint32(h, value_field, mapvalue_enum, &enum_attr);
       upb_handlerattr_uninit(&enum_attr);
       break;
@@ -12198,13 +12677,13 @@ void printer_sethandlers(const void *closure, upb_handlers *h) {
   bool is_mapentry = upb_msgdef_mapentry(md);
   upb_handlerattr empty_attr = UPB_HANDLERATTR_INITIALIZER;
   upb_msg_field_iter i;
-
-  UPB_UNUSED(closure);
+  const bool *preserve_fieldnames_ptr = closure;
+  const bool preserve_fieldnames = *preserve_fieldnames_ptr;
 
   if (is_mapentry) {
     /* mapentry messages are sufficiently different that we handle them
      * separately. */
-    printer_sethandlers_mapentry(closure, h);
+    printer_sethandlers_mapentry(closure, preserve_fieldnames, h);
     return;
   }
 
@@ -12225,7 +12704,8 @@ void printer_sethandlers(const void *closure, upb_handlers *h) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
 
     upb_handlerattr name_attr = UPB_HANDLERATTR_INITIALIZER;
-    upb_handlerattr_sethandlerdata(&name_attr, newstrpc(h, f));
+    upb_handlerattr_sethandlerdata(&name_attr,
+                                   newstrpc(h, f, preserve_fieldnames));
 
     if (upb_fielddef_ismap(f)) {
       upb_handlers_setstartseq(h, f, startmap, &name_attr);
@@ -12248,7 +12728,7 @@ void printer_sethandlers(const void *closure, upb_handlers *h) {
          * option later to control this behavior, but we will wait for a real
          * need first. */
         upb_handlerattr enum_attr = UPB_HANDLERATTR_INITIALIZER;
-        set_enum_hd(h, f, &enum_attr);
+        set_enum_hd(h, f, preserve_fieldnames, &enum_attr);
 
         if (upb_fielddef_isseq(f)) {
           upb_handlers_setint32(h, f, repeated_enum, &enum_attr);
@@ -12325,6 +12805,8 @@ upb_sink *upb_json_printer_input(upb_json_printer *p) {
 }
 
 const upb_handlers *upb_json_printer_newhandlers(const upb_msgdef *md,
+                                                 bool preserve_fieldnames,
                                                  const void *owner) {
-  return upb_handlers_newfrozen(md, owner, printer_sethandlers, NULL);
+  return upb_handlers_newfrozen(
+      md, owner, printer_sethandlers, &preserve_fieldnames);
 }
diff --git a/ruby/ext/google/protobuf_c/upb.h b/ruby/ext/google/protobuf_c/upb.h
index 0be5b296..2faf74e5 100644
--- a/ruby/ext/google/protobuf_c/upb.h
+++ b/ruby/ext/google/protobuf_c/upb.h
@@ -5,6 +5,7 @@
 **
 ** - upb::MessageDef (upb_msgdef): describes a "message" construct.
 ** - upb::FieldDef (upb_fielddef): describes a message field.
+** - upb::FileDef (upb_filedef): describes a .proto file and its defs.
 ** - upb::EnumDef (upb_enumdef): describes an enum.
 ** - upb::OneofDef (upb_oneofdef): describes a oneof.
 ** - upb::Def (upb_def): base class of all the others.
@@ -79,6 +80,18 @@
 #include <stdbool.h>
 #include <stddef.h>
 
+#ifdef __cplusplus
+namespace upb {
+class Allocator;
+class Arena;
+class Environment;
+class ErrorSpace;
+class Status;
+template <int N> class InlinedArena;
+template <int N> class InlinedEnvironment;
+}
+#endif
+
 /* UPB_INLINE: inline if possible, emit standalone code if required. */
 #ifdef __cplusplus
 #define UPB_INLINE inline
@@ -146,6 +159,7 @@
 #define UPB_ASSERT_STDLAYOUT(type) \
   static_assert(std::is_standard_layout<type>::value, \
                 #type " must be standard layout");
+#define UPB_FINAL final
 #else  /* !defined(UPB_CXX11) */
 #define UPB_DISALLOW_COPY_AND_ASSIGN(class_name) \
   class_name(const class_name&); \
@@ -155,6 +169,7 @@
   ~class_name(); \
   UPB_DISALLOW_COPY_AND_ASSIGN(class_name)
 #define UPB_ASSERT_STDLAYOUT(type)
+#define UPB_FINAL
 #endif
 
 /* UPB_DECLARE_TYPE()
@@ -256,6 +271,7 @@
 /* Generic function type. */
 typedef void upb_func();
 
+
 /* C++ Casts ******************************************************************/
 
 #ifdef __cplusplus
@@ -333,243 +349,430 @@ class PointerBase2 : public PointerBase<T, Base> {
 #endif
 
 
-/* upb::reffed_ptr ************************************************************/
+/* upb::ErrorSpace ************************************************************/
+
+/* A upb::ErrorSpace represents some domain of possible error values.  This lets
+ * upb::Status attach specific error codes to operations, like POSIX/C errno,
+ * Win32 error codes, etc.  Clients who want to know the very specific error
+ * code can check the error space and then know the type of the integer code.
+ *
+ * NOTE: upb::ErrorSpace is currently not used and should be considered
+ * experimental.  It is important primarily in cases where upb is performing
+ * I/O, but upb doesn't currently have any components that do this. */
+
+UPB_DECLARE_TYPE(upb::ErrorSpace, upb_errorspace)
 
 #ifdef __cplusplus
+class upb::ErrorSpace {
+#else
+struct upb_errorspace {
+#endif
+  const char *name;
+};
 
-#include <algorithm>  /* For std::swap(). */
 
-namespace upb {
+/* upb::Status ****************************************************************/
 
-/* Provides RAII semantics for upb refcounted objects.  Each reffed_ptr owns a
- * ref on whatever object it points to (if any). */
-template <class T> class reffed_ptr {
+/* upb::Status represents a success or failure status and error message.
+ * It owns no resources and allocates no memory, so it should work
+ * even in OOM situations. */
+UPB_DECLARE_TYPE(upb::Status, upb_status)
+
+/* The maximum length of an error message before it will get truncated. */
+#define UPB_STATUS_MAX_MESSAGE 128
+
+UPB_BEGIN_EXTERN_C
+
+const char *upb_status_errmsg(const upb_status *status);
+bool upb_ok(const upb_status *status);
+upb_errorspace *upb_status_errspace(const upb_status *status);
+int upb_status_errcode(const upb_status *status);
+
+/* Any of the functions that write to a status object allow status to be NULL,
+ * to support use cases where the function's caller does not care about the
+ * status message. */
+void upb_status_clear(upb_status *status);
+void upb_status_seterrmsg(upb_status *status, const char *msg);
+void upb_status_seterrf(upb_status *status, const char *fmt, ...);
+void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args);
+void upb_status_copy(upb_status *to, const upb_status *from);
+
+UPB_END_EXTERN_C
+
+#ifdef __cplusplus
+
+class upb::Status {
  public:
-  reffed_ptr() : ptr_(NULL) {}
+  Status() { upb_status_clear(this); }
 
-  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
-  template <class U>
-  reffed_ptr(U* val, const void* ref_donor = NULL)
-      : ptr_(upb::upcast(val)) {
-    if (ref_donor) {
-      assert(ptr_);
-      ptr_->DonateRef(ref_donor, this);
-    } else if (ptr_) {
-      ptr_->Ref(this);
-    }
-  }
+  /* Returns true if there is no error. */
+  bool ok() const { return upb_ok(this); }
 
-  template <class U>
-  reffed_ptr(const reffed_ptr<U>& other)
-      : ptr_(upb::upcast(other.get())) {
-    if (ptr_) ptr_->Ref(this);
-  }
+  /* Optional error space and code, useful if the caller wants to
+   * programmatically check the specific kind of error. */
+  ErrorSpace* error_space() { return upb_status_errspace(this); }
+  int error_code() const { return upb_status_errcode(this); }
 
-  ~reffed_ptr() { if (ptr_) ptr_->Unref(this); }
+  /* The returned string is invalidated by any other call into the status. */
+  const char *error_message() const { return upb_status_errmsg(this); }
 
-  template <class U>
-  reffed_ptr& operator=(const reffed_ptr<U>& other) {
-    reset(other.get());
-    return *this;
+  /* The error message will be truncated if it is longer than
+   * UPB_STATUS_MAX_MESSAGE-4. */
+  void SetErrorMessage(const char* msg) { upb_status_seterrmsg(this, msg); }
+  void SetFormattedErrorMessage(const char* fmt, ...) {
+    va_list args;
+    va_start(args, fmt);
+    upb_status_vseterrf(this, fmt, args);
+    va_end(args);
   }
 
-  reffed_ptr& operator=(const reffed_ptr& other) {
-    reset(other.get());
-    return *this;
-  }
+  /* Resets the status to a successful state with no message. */
+  void Clear() { upb_status_clear(this); }
 
-  /* TODO(haberman): add C++11 move construction/assignment for greater
-   * efficiency. */
+  void CopyFrom(const Status& other) { upb_status_copy(this, &other); }
 
-  void swap(reffed_ptr& other) {
-    if (ptr_ == other.ptr_) {
-      return;
-    }
+ private:
+  UPB_DISALLOW_COPY_AND_ASSIGN(Status)
+#else
+struct upb_status {
+#endif
+  bool ok_;
 
-    if (ptr_) ptr_->DonateRef(this, &other);
-    if (other.ptr_) other.ptr_->DonateRef(&other, this);
-    std::swap(ptr_, other.ptr_);
-  }
+  /* Specific status code defined by some error space (optional). */
+  int code_;
+  upb_errorspace *error_space_;
 
-  T& operator*() const {
-    assert(ptr_);
-    return *ptr_;
-  }
+  /* TODO(haberman): add file/line of error? */
 
-  T* operator->() const {
-    assert(ptr_);
-    return ptr_;
-  }
+  /* Error message; NULL-terminated. */
+  char msg[UPB_STATUS_MAX_MESSAGE];
+};
 
-  T* get() const { return ptr_; }
+#define UPB_STATUS_INIT {true, 0, NULL, {0}}
 
-  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
-  template <class U>
-  void reset(U* ptr = NULL, const void* ref_donor = NULL) {
-    reffed_ptr(ptr, ref_donor).swap(*this);
-  }
 
-  template <class U>
-  reffed_ptr<U> down_cast() {
-    return reffed_ptr<U>(upb::down_cast<U*>(get()));
-  }
+/** Built-in error spaces. ****************************************************/
 
-  template <class U>
-  reffed_ptr<U> dyn_cast() {
-    return reffed_ptr<U>(upb::dyn_cast<U*>(get()));
-  }
+/* Errors raised by upb that we want to be able to detect programmatically. */
+typedef enum {
+  UPB_NOMEM   /* Can't reuse ENOMEM because it is POSIX, not ISO C. */
+} upb_errcode_t;
 
-  /* Plain release() is unsafe; if we were the only owner, it would leak the
-   * object.  Instead we provide this: */
-  T* ReleaseTo(const void* new_owner) {
-    T* ret = NULL;
-    ptr_->DonateRef(this, new_owner);
-    std::swap(ret, ptr_);
-    return ret;
-  }
+extern upb_errorspace upb_upberr;
+
+void upb_upberr_setoom(upb_status *s);
+
+/* Since errno is defined by standard C, we define an error space for it in
+ * core upb.  Other error spaces should be defined in other, platform-specific
+ * modules. */
+
+extern upb_errorspace upb_errnoerr;
+
+
+/** upb::Allocator ************************************************************/
+
+/* A upb::Allocator is a possibly-stateful allocator object.
+ *
+ * It could either be an arena allocator (which doesn't require individual
+ * free() calls) or a regular malloc() (which does).  The client must therefore
+ * free memory unless it knows that the allocator is an arena allocator. */
+UPB_DECLARE_TYPE(upb::Allocator, upb_alloc)
+
+/* A malloc()/free() function.
+ * If "size" is 0 then the function acts like free(), otherwise it acts like
+ * realloc().  Only "oldsize" bytes from a previous allocation are preserved. */
+typedef void *upb_alloc_func(upb_alloc *alloc, void *ptr, size_t oldsize,
+                             size_t size);
+
+#ifdef __cplusplus
+
+class upb::Allocator UPB_FINAL {
+ public:
+  Allocator() {}
 
  private:
-  T* ptr_;
+  UPB_DISALLOW_COPY_AND_ASSIGN(Allocator)
+
+ public:
+#else
+struct upb_alloc {
+#endif  /* __cplusplus */
+  upb_alloc_func *func;
 };
 
-}  /* namespace upb */
+UPB_INLINE void *upb_malloc(upb_alloc *alloc, size_t size) {
+  assert(size > 0);
+  return alloc->func(alloc, NULL, 0, size);
+}
 
-#endif  /* __cplusplus */
+UPB_INLINE void *upb_realloc(upb_alloc *alloc, void *ptr, size_t oldsize,
+                             size_t size) {
+  assert(size > 0);
+  return alloc->func(alloc, ptr, oldsize, size);
+}
 
+UPB_INLINE void upb_free(upb_alloc *alloc, void *ptr) {
+  alloc->func(alloc, ptr, 0, 0);
+}
 
-/* upb::Status ****************************************************************/
+/* The global allocator used by upb.  Uses the standard malloc()/free(). */
 
-#ifdef __cplusplus
-namespace upb {
-class ErrorSpace;
-class Status;
+extern upb_alloc upb_alloc_global;
+
+/* Functions that hard-code the global malloc.
+ *
+ * We still get benefit because we can put custom logic into our global
+ * allocator, like injecting out-of-memory faults in debug/testing builds. */
+
+UPB_INLINE void *upb_gmalloc(size_t size) {
+  return upb_malloc(&upb_alloc_global, size);
 }
-#endif
 
-UPB_DECLARE_TYPE(upb::ErrorSpace, upb_errorspace)
-UPB_DECLARE_TYPE(upb::Status, upb_status)
+UPB_INLINE void *upb_grealloc(void *ptr, size_t oldsize, size_t size) {
+  return upb_realloc(&upb_alloc_global, ptr, oldsize, size);
+}
 
-/* The maximum length of an error message before it will get truncated. */
-#define UPB_STATUS_MAX_MESSAGE 128
+UPB_INLINE void upb_gfree(void *ptr) {
+  upb_free(&upb_alloc_global, ptr);
+}
 
-/* An error callback function is used to report errors from some component.
- * The function can return "true" to indicate that the component should try
- * to recover and proceed, but this is not always possible. */
-typedef bool upb_errcb_t(void *closure, const upb_status* status);
+/* upb::Arena *****************************************************************/
+
+/* upb::Arena is a specific allocator implementation that uses arena allocation.
+ * The user provides an allocator that will be used to allocate the underlying
+ * arena blocks.  Arenas by nature do not require the individual allocations
+ * to be freed.  However the Arena does allow users to register cleanup
+ * functions that will run when the arena is destroyed.
+ *
+ * A upb::Arena is *not* thread-safe.
+ *
+ * You could write a thread-safe arena allocator that satisfies the
+ * upb::Allocator interface, but it would not be as efficient for the
+ * single-threaded case. */
+UPB_DECLARE_TYPE(upb::Arena, upb_arena)
+
+typedef void upb_cleanup_func(void *ud);
+
+#define UPB_ARENA_BLOCK_OVERHEAD (sizeof(size_t)*4)
+
+UPB_BEGIN_EXTERN_C
+
+void upb_arena_init(upb_arena *a);
+void upb_arena_init2(upb_arena *a, void *mem, size_t n, upb_alloc *alloc);
+void upb_arena_uninit(upb_arena *a);
+upb_alloc *upb_arena_alloc(upb_arena *a);
+bool upb_arena_addcleanup(upb_arena *a, upb_cleanup_func *func, void *ud);
+size_t upb_arena_bytesallocated(const upb_arena *a);
+void upb_arena_setnextblocksize(upb_arena *a, size_t size);
+void upb_arena_setmaxblocksize(upb_arena *a, size_t size);
+
+UPB_END_EXTERN_C
 
 #ifdef __cplusplus
-class upb::ErrorSpace {
+
+class upb::Arena {
+ public:
+  /* A simple arena with no initial memory block and the default allocator. */
+  Arena() { upb_arena_init(this); }
+
+  /* Constructs an arena with the given initial block which allocates blocks
+   * with the given allocator.  The given allocator must outlive the Arena.
+   *
+   * If you pass NULL for the allocator it will default to the global allocator
+   * upb_alloc_global, and NULL/0 for the initial block will cause there to be
+   * no initial block. */
+  Arena(void *mem, size_t len, Allocator* a) {
+    upb_arena_init2(this, mem, len, a);
+  }
+
+  ~Arena() { upb_arena_uninit(this); }
+
+  /* Sets the size of the next block the Arena will request (unless the
+   * requested allocation is larger).  Each block will double in size until the
+   * max limit is reached. */
+  void SetNextBlockSize(size_t size) { upb_arena_setnextblocksize(this, size); }
+
+  /* Sets the maximum block size.  No blocks larger than this will be requested
+   * from the underlying allocator unless individual arena allocations are
+   * larger. */
+  void SetMaxBlockSize(size_t size) { upb_arena_setmaxblocksize(this, size); }
+
+  /* Allows this arena to be used as a generic allocator.
+   *
+   * The arena does not need free() calls so when using Arena as an allocator
+   * it is safe to skip them.  However they are no-ops so there is no harm in
+   * calling free() either. */
+  Allocator* allocator() { return upb_arena_alloc(this); }
+
+  /* Add a cleanup function to run when the arena is destroyed.
+   * Returns false on out-of-memory. */
+  bool AddCleanup(upb_cleanup_func* func, void* ud) {
+    return upb_arena_addcleanup(this, func, ud);
+  }
+
+  /* Total number of bytes that have been allocated.  It is undefined what
+   * Realloc() does to this counter. */
+  size_t BytesAllocated() const {
+    return upb_arena_bytesallocated(this);
+  }
+
+ private:
+  UPB_DISALLOW_COPY_AND_ASSIGN(Arena)
+
 #else
-struct upb_errorspace {
-#endif
-  const char *name;
-  /* Should the error message in the status object according to this code. */
-  void (*set_message)(upb_status* status, int code);
+struct upb_arena {
+#endif  /* __cplusplus */
+  /* We implement the allocator interface.
+   * This must be the first member of upb_arena! */
+  upb_alloc alloc;
+
+  /* Allocator to allocate arena blocks.  We are responsible for freeing these
+   * when we are destroyed. */
+  upb_alloc *block_alloc;
+
+  size_t bytes_allocated;
+  size_t next_block_size;
+  size_t max_block_size;
+
+  /* Linked list of blocks.  Points to an arena_block, defined in env.c */
+  void *block_head;
+
+  /* Cleanup entries.  Pointer to a cleanup_ent, defined in env.c */
+  void *cleanup_head;
+
+  /* For future expansion, since the size of this struct is exposed to users. */
+  void *future1;
+  void *future2;
 };
 
-#ifdef __cplusplus
 
-/* Object representing a success or failure status.
- * It owns no resources and allocates no memory, so it should work
- * even in OOM situations. */
+/* upb::Environment ***********************************************************/
 
-class upb::Status {
- public:
-  Status();
+/* A upb::Environment provides a means for injecting malloc and an
+ * error-reporting callback into encoders/decoders.  This allows them to be
+ * independent of nearly all assumptions about their actual environment.
+ *
+ * It is also a container for allocating the encoders/decoders themselves that
+ * insulates clients from knowing their actual size.  This provides ABI
+ * compatibility even if the size of the objects change.  And this allows the
+ * structure definitions to be in the .c files instead of the .h files, making
+ * the .h files smaller and more readable.
+ *
+ * We might want to consider renaming this to "Pipeline" if/when the concept of
+ * a pipeline element becomes more formalized. */
+UPB_DECLARE_TYPE(upb::Environment, upb_env)
 
-  /* Returns true if there is no error. */
-  bool ok() const;
+/* A function that receives an error report from an encoder or decoder.  The
+ * callback can return true to request that the error should be recovered, but
+ * if the error is not recoverable this has no effect. */
+typedef bool upb_error_func(void *ud, const upb_status *status);
 
-  /* Optional error space and code, useful if the caller wants to
-   * programmatically check the specific kind of error. */
-  ErrorSpace* error_space();
-  int code() const;
+UPB_BEGIN_EXTERN_C
 
-  const char *error_message() const;
+void upb_env_init(upb_env *e);
+void upb_env_init2(upb_env *e, void *mem, size_t n, upb_alloc *alloc);
+void upb_env_uninit(upb_env *e);
 
-  /* The error message will be truncated if it is longer than
-   * UPB_STATUS_MAX_MESSAGE-4. */
-  void SetErrorMessage(const char* msg);
-  void SetFormattedErrorMessage(const char* fmt, ...);
+void upb_env_initonly(upb_env *e);
 
-  /* If there is no error message already, this will use the ErrorSpace to
-   * populate the error message for this code.  The caller can still call
-   * SetErrorMessage() to give a more specific message. */
-  void SetErrorCode(ErrorSpace* space, int code);
+upb_arena *upb_env_arena(upb_env *e);
+bool upb_env_ok(const upb_env *e);
+void upb_env_seterrorfunc(upb_env *e, upb_error_func *func, void *ud);
 
-  /* Resets the status to a successful state with no message. */
-  void Clear();
+/* Convenience wrappers around the methods of the contained arena. */
+void upb_env_reporterrorsto(upb_env *e, upb_status *s);
+bool upb_env_reporterror(upb_env *e, const upb_status *s);
+void *upb_env_malloc(upb_env *e, size_t size);
+void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size);
+void upb_env_free(upb_env *e, void *ptr);
+bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud);
+size_t upb_env_bytesallocated(const upb_env *e);
+
+UPB_END_EXTERN_C
+
+#ifdef __cplusplus
+
+class upb::Environment {
+ public:
+  /* The given Arena must outlive this environment. */
+  Environment() { upb_env_initonly(this); }
+
+  Environment(void *mem, size_t len, Allocator *a) : arena_(mem, len, a) {
+    upb_env_initonly(this);
+  }
 
-  void CopyFrom(const Status& other);
+  Arena* arena() { return upb_env_arena(this); }
+
+  /* Set a custom error reporting function. */
+  void SetErrorFunction(upb_error_func* func, void* ud) {
+    upb_env_seterrorfunc(this, func, ud);
+  }
+
+  /* Set the error reporting function to simply copy the status to the given
+   * status and abort. */
+  void ReportErrorsTo(Status* status) { upb_env_reporterrorsto(this, status); }
+
+  /* Returns true if all allocations and AddCleanup() calls have succeeded,
+   * and no errors were reported with ReportError() (except ones that recovered
+   * successfully). */
+  bool ok() const { return upb_env_ok(this); }
+
+  /* Reports an error to this environment's callback, returning true if
+   * the caller should try to recover. */
+  bool ReportError(const Status* status) {
+    return upb_env_reporterror(this, status);
+  }
 
  private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Status)
+  UPB_DISALLOW_COPY_AND_ASSIGN(Environment)
+
 #else
-struct upb_status {
-#endif
+struct upb_env {
+#endif  /* __cplusplus */
+  upb_arena arena_;
+  upb_error_func *error_func_;
+  void *error_ud_;
   bool ok_;
+};
 
-  /* Specific status code defined by some error space (optional). */
-  int code_;
-  upb_errorspace *error_space_;
 
-  /* Error message; NULL-terminated. */
-  char msg[UPB_STATUS_MAX_MESSAGE];
-};
+/* upb::InlinedArena **********************************************************/
+/* upb::InlinedEnvironment ****************************************************/
 
-#define UPB_STATUS_INIT {true, 0, NULL, {0}}
+/* upb::InlinedArena and upb::InlinedEnvironment seed their arenas with a
+ * predefined amount of memory.  No heap memory will be allocated until the
+ * initial block is exceeded.
+ *
+ * These types only exist in C++ */
 
 #ifdef __cplusplus
-extern "C" {
-#endif
 
-/* The returned string is invalidated by any other call into the status. */
-const char *upb_status_errmsg(const upb_status *status);
-bool upb_ok(const upb_status *status);
-upb_errorspace *upb_status_errspace(const upb_status *status);
-int upb_status_errcode(const upb_status *status);
+template <int N> class upb::InlinedArena : public upb::Arena {
+ public:
+  InlinedArena() : Arena(initial_block_, N, NULL) {}
+  explicit InlinedArena(Allocator* a) : Arena(initial_block_, N, a) {}
 
-/* Any of the functions that write to a status object allow status to be NULL,
- * to support use cases where the function's caller does not care about the
- * status message. */
-void upb_status_clear(upb_status *status);
-void upb_status_seterrmsg(upb_status *status, const char *msg);
-void upb_status_seterrf(upb_status *status, const char *fmt, ...);
-void upb_status_vseterrf(upb_status *status, const char *fmt, va_list args);
-void upb_status_seterrcode(upb_status *status, upb_errorspace *space, int code);
-void upb_status_copy(upb_status *to, const upb_status *from);
+ private:
+  UPB_DISALLOW_COPY_AND_ASSIGN(InlinedArena)
 
-#ifdef __cplusplus
-}  /* extern "C" */
+  char initial_block_[N + UPB_ARENA_BLOCK_OVERHEAD];
+};
 
-namespace upb {
+template <int N> class upb::InlinedEnvironment : public upb::Environment {
+ public:
+  InlinedEnvironment() : Environment(initial_block_, N, NULL) {}
+  explicit InlinedEnvironment(Allocator *a)
+      : Environment(initial_block_, N, a) {}
 
-/* C++ Wrappers */
-inline Status::Status() { Clear(); }
-inline bool Status::ok() const { return upb_ok(this); }
-inline const char* Status::error_message() const {
-  return upb_status_errmsg(this);
-}
-inline void Status::SetErrorMessage(const char* msg) {
-  upb_status_seterrmsg(this, msg);
-}
-inline void Status::SetFormattedErrorMessage(const char* fmt, ...) {
-  va_list args;
-  va_start(args, fmt);
-  upb_status_vseterrf(this, fmt, args);
-  va_end(args);
-}
-inline void Status::SetErrorCode(ErrorSpace* space, int code) {
-  upb_status_seterrcode(this, space, code);
-}
-inline void Status::Clear() { upb_status_clear(this); }
-inline void Status::CopyFrom(const Status& other) {
-  upb_status_copy(this, &other);
-}
+ private:
+  UPB_DISALLOW_COPY_AND_ASSIGN(InlinedEnvironment)
+
+  char initial_block_[N + UPB_ARENA_BLOCK_OVERHEAD];
+};
+
+#endif  /* __cplusplus */
 
-}  /* namespace upb */
 
-#endif
 
 #endif  /* UPB_H_ */
 
@@ -611,10 +814,14 @@ typedef struct {
 #endif
 
 /* Like strdup(), which isn't always available since it's not ANSI C. */
-char *upb_strdup(const char *s);
+char *upb_strdup(const char *s, upb_alloc *a);
 /* Variant that works with a length-delimited rather than NULL-delimited string,
  * as supported by strtable. */
-char *upb_strdup2(const char *s, size_t len);
+char *upb_strdup2(const char *s, size_t len, upb_alloc *a);
+
+UPB_INLINE char *upb_gstrdup(const char *s) {
+  return upb_strdup(s, &upb_alloc_global);
+}
 
 UPB_INLINE void _upb_value_setval(upb_value *v, uint64_t val,
                                   upb_ctype_t ctype) {
@@ -791,14 +998,40 @@ typedef struct {
    * initialize const hash tables.  Then we cast away const when we have to.
    */
   const upb_tabent *entries;
+
+#ifndef NDEBUG
+  /* This table's allocator.  We make the user pass it in to every relevant
+   * function and only use this to check it in debug mode.  We do this solely
+   * to keep upb_table as small as possible.  This might seem slightly paranoid
+   * but the plan is to use upb_table for all map fields and extension sets in
+   * a forthcoming message representation, so there could be a lot of these.
+   * If this turns out to be too annoying later, we can change it (since this
+   * is an internal-only header file). */
+  upb_alloc *alloc;
+#endif
 } upb_table;
 
+#ifdef NDEBUG
+#  define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
+     {count, mask, ctype, size_lg2, entries}
+#else
+#  ifdef UPB_DEBUG_REFS
+/* At the moment the only mutable tables we statically initialize are debug
+ * ref tables. */
+#    define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
+       {count, mask, ctype, size_lg2, entries, &upb_alloc_debugrefs}
+#  else
+#    define UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries) \
+       {count, mask, ctype, size_lg2, entries, NULL}
+#  endif
+#endif
+
 typedef struct {
   upb_table t;
 } upb_strtable;
 
 #define UPB_STRTABLE_INIT(count, mask, ctype, size_lg2, entries) \
-  {{count, mask, ctype, size_lg2, entries}}
+  {UPB_TABLE_INIT(count, mask, ctype, size_lg2, entries)}
 
 #define UPB_EMPTY_STRTABLE_INIT(ctype)                           \
   UPB_STRTABLE_INIT(0, 0, ctype, 0, NULL)
@@ -811,7 +1044,7 @@ typedef struct {
 } upb_inttable;
 
 #define UPB_INTTABLE_INIT(count, mask, ctype, size_lg2, ent, a, asize, acount) \
-  {{count, mask, ctype, size_lg2, ent}, a, asize, acount}
+  {UPB_TABLE_INIT(count, mask, ctype, size_lg2, ent), a, asize, acount}
 
 #define UPB_EMPTY_INTTABLE_INIT(ctype) \
   UPB_INTTABLE_INIT(0, 0, ctype, 0, NULL, NULL, 0, 0)
@@ -851,10 +1084,26 @@ UPB_INLINE bool upb_arrhas(upb_tabval key) {
 
 /* Initialize and uninitialize a table, respectively.  If memory allocation
  * failed, false is returned that the table is uninitialized. */
-bool upb_inttable_init(upb_inttable *table, upb_ctype_t ctype);
-bool upb_strtable_init(upb_strtable *table, upb_ctype_t ctype);
-void upb_inttable_uninit(upb_inttable *table);
-void upb_strtable_uninit(upb_strtable *table);
+bool upb_inttable_init2(upb_inttable *table, upb_ctype_t ctype, upb_alloc *a);
+bool upb_strtable_init2(upb_strtable *table, upb_ctype_t ctype, upb_alloc *a);
+void upb_inttable_uninit2(upb_inttable *table, upb_alloc *a);
+void upb_strtable_uninit2(upb_strtable *table, upb_alloc *a);
+
+UPB_INLINE bool upb_inttable_init(upb_inttable *table, upb_ctype_t ctype) {
+  return upb_inttable_init2(table, ctype, &upb_alloc_global);
+}
+
+UPB_INLINE bool upb_strtable_init(upb_strtable *table, upb_ctype_t ctype) {
+  return upb_strtable_init2(table, ctype, &upb_alloc_global);
+}
+
+UPB_INLINE void upb_inttable_uninit(upb_inttable *table) {
+  upb_inttable_uninit2(table, &upb_alloc_global);
+}
+
+UPB_INLINE void upb_strtable_uninit(upb_strtable *table) {
+  upb_strtable_uninit2(table, &upb_alloc_global);
+}
 
 /* Returns the number of values in the table. */
 size_t upb_inttable_count(const upb_inttable *t);
@@ -869,9 +1118,20 @@ UPB_INLINE size_t upb_strtable_count(const upb_strtable *t) {
  *
  * If a table resize was required but memory allocation failed, false is
  * returned and the table is unchanged. */
-bool upb_inttable_insert(upb_inttable *t, uintptr_t key, upb_value val);
-bool upb_strtable_insert2(upb_strtable *t, const char *key, size_t len,
-                          upb_value val);
+bool upb_inttable_insert2(upb_inttable *t, uintptr_t key, upb_value val,
+                          upb_alloc *a);
+bool upb_strtable_insert3(upb_strtable *t, const char *key, size_t len,
+                          upb_value val, upb_alloc *a);
+
+UPB_INLINE bool upb_inttable_insert(upb_inttable *t, uintptr_t key,
+                                    upb_value val) {
+  return upb_inttable_insert2(t, key, val, &upb_alloc_global);
+}
+
+UPB_INLINE bool upb_strtable_insert2(upb_strtable *t, const char *key,
+                                     size_t len, upb_value val) {
+  return upb_strtable_insert3(t, key, len, val, &upb_alloc_global);
+}
 
 /* For NULL-terminated strings. */
 UPB_INLINE bool upb_strtable_insert(upb_strtable *t, const char *key,
@@ -894,8 +1154,13 @@ UPB_INLINE bool upb_strtable_lookup(const upb_strtable *t, const char *key,
 /* Removes an item from the table.  Returns true if the remove was successful,
  * and stores the removed item in *val if non-NULL. */
 bool upb_inttable_remove(upb_inttable *t, uintptr_t key, upb_value *val);
-bool upb_strtable_remove2(upb_strtable *t, const char *key, size_t len,
-                          upb_value *val);
+bool upb_strtable_remove3(upb_strtable *t, const char *key, size_t len,
+                          upb_value *val, upb_alloc *alloc);
+
+UPB_INLINE bool upb_strtable_remove2(upb_strtable *t, const char *key,
+                                     size_t len, upb_value *val) {
+  return upb_strtable_remove3(t, key, len, val, &upb_alloc_global);
+}
 
 /* For NULL-terminated strings. */
 UPB_INLINE bool upb_strtable_remove(upb_strtable *t, const char *key,
@@ -910,19 +1175,33 @@ bool upb_inttable_replace(upb_inttable *t, uintptr_t key, upb_value val);
 
 /* Handy routines for treating an inttable like a stack.  May not be mixed with
  * other insert/remove calls. */
-bool upb_inttable_push(upb_inttable *t, upb_value val);
+bool upb_inttable_push2(upb_inttable *t, upb_value val, upb_alloc *a);
 upb_value upb_inttable_pop(upb_inttable *t);
 
+UPB_INLINE bool upb_inttable_push(upb_inttable *t, upb_value val) {
+  return upb_inttable_push2(t, val, &upb_alloc_global);
+}
+
 /* Convenience routines for inttables with pointer keys. */
-bool upb_inttable_insertptr(upb_inttable *t, const void *key, upb_value val);
+bool upb_inttable_insertptr2(upb_inttable *t, const void *key, upb_value val,
+                             upb_alloc *a);
 bool upb_inttable_removeptr(upb_inttable *t, const void *key, upb_value *val);
 bool upb_inttable_lookupptr(
     const upb_inttable *t, const void *key, upb_value *val);
 
+UPB_INLINE bool upb_inttable_insertptr(upb_inttable *t, const void *key,
+                                       upb_value val) {
+  return upb_inttable_insertptr2(t, key, val, &upb_alloc_global);
+}
+
 /* Optimizes the table for the current set of entries, for both memory use and
  * lookup time.  Client should call this after all entries have been inserted;
  * inserting more entries is legal, but will likely require a table resize. */
-void upb_inttable_compact(upb_inttable *t);
+void upb_inttable_compact2(upb_inttable *t, upb_alloc *a);
+
+UPB_INLINE void upb_inttable_compact(upb_inttable *t) {
+  upb_inttable_compact2(t, &upb_alloc_global);
+}
 
 /* A special-case inlinable version of the lookup routine for 32-bit
  * integers. */
@@ -951,7 +1230,7 @@ UPB_INLINE bool upb_inttable_lookup32(const upb_inttable *t, uint32_t key,
 }
 
 /* Exposed for testing only. */
-bool upb_strtable_resize(upb_strtable *t, size_t size_lg2);
+bool upb_strtable_resize(upb_strtable *t, size_t size_lg2, upb_alloc *a);
 
 /* Iterators ******************************************************************/
 
@@ -996,8 +1275,8 @@ typedef struct {
 void upb_strtable_begin(upb_strtable_iter *i, const upb_strtable *t);
 void upb_strtable_next(upb_strtable_iter *i);
 bool upb_strtable_done(const upb_strtable_iter *i);
-const char *upb_strtable_iter_key(upb_strtable_iter *i);
-size_t upb_strtable_iter_keylength(upb_strtable_iter *i);
+const char *upb_strtable_iter_key(const upb_strtable_iter *i);
+size_t upb_strtable_iter_keylength(const upb_strtable_iter *i);
 upb_value upb_strtable_iter_value(const upb_strtable_iter *i);
 void upb_strtable_iter_setdone(upb_strtable_iter *i);
 bool upb_strtable_iter_isequal(const upb_strtable_iter *i1,
@@ -1050,7 +1329,10 @@ bool upb_inttable_iter_isequal(const upb_inttable_iter *i1,
 /* #define UPB_DEBUG_REFS */
 
 #ifdef __cplusplus
-namespace upb { class RefCounted; }
+namespace upb {
+class RefCounted;
+template <class T> class reffed_ptr;
+}
 #endif
 
 UPB_DECLARE_TYPE(upb::RefCounted, upb_refcounted)
@@ -1118,10 +1400,12 @@ struct upb_refcounted {
 };
 
 #ifdef UPB_DEBUG_REFS
-#define UPB_REFCOUNT_INIT(refs, ref2s) \
-    {&static_refcount, NULL, NULL, 0, true, refs, ref2s}
+extern upb_alloc upb_alloc_debugrefs;
+#define UPB_REFCOUNT_INIT(vtbl, refs, ref2s) \
+    {&static_refcount, NULL, vtbl, 0, true, refs, ref2s}
 #else
-#define UPB_REFCOUNT_INIT(refs, ref2s) {&static_refcount, NULL, NULL, 0, true}
+#define UPB_REFCOUNT_INIT(vtbl, refs, ref2s) \
+    {&static_refcount, NULL, vtbl, 0, true}
 #endif
 
 UPB_BEGIN_EXTERN_C
@@ -1254,6 +1538,111 @@ inline void RefCounted::CheckRef(const void *owner) const {
 }  /* namespace upb */
 #endif
 
+
+/* upb::reffed_ptr ************************************************************/
+
+#ifdef __cplusplus
+
+#include <algorithm>  /* For std::swap(). */
+
+/* Provides RAII semantics for upb refcounted objects.  Each reffed_ptr owns a
+ * ref on whatever object it points to (if any). */
+template <class T> class upb::reffed_ptr {
+ public:
+  reffed_ptr() : ptr_(NULL) {}
+
+  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
+  template <class U>
+  reffed_ptr(U* val, const void* ref_donor = NULL)
+      : ptr_(upb::upcast(val)) {
+    if (ref_donor) {
+      assert(ptr_);
+      ptr_->DonateRef(ref_donor, this);
+    } else if (ptr_) {
+      ptr_->Ref(this);
+    }
+  }
+
+  template <class U>
+  reffed_ptr(const reffed_ptr<U>& other)
+      : ptr_(upb::upcast(other.get())) {
+    if (ptr_) ptr_->Ref(this);
+  }
+
+  reffed_ptr(const reffed_ptr& other)
+      : ptr_(upb::upcast(other.get())) {
+    if (ptr_) ptr_->Ref(this);
+  }
+
+  ~reffed_ptr() { if (ptr_) ptr_->Unref(this); }
+
+  template <class U>
+  reffed_ptr& operator=(const reffed_ptr<U>& other) {
+    reset(other.get());
+    return *this;
+  }
+
+  reffed_ptr& operator=(const reffed_ptr& other) {
+    reset(other.get());
+    return *this;
+  }
+
+  /* TODO(haberman): add C++11 move construction/assignment for greater
+   * efficiency. */
+
+  void swap(reffed_ptr& other) {
+    if (ptr_ == other.ptr_) {
+      return;
+    }
+
+    if (ptr_) ptr_->DonateRef(this, &other);
+    if (other.ptr_) other.ptr_->DonateRef(&other, this);
+    std::swap(ptr_, other.ptr_);
+  }
+
+  T& operator*() const {
+    assert(ptr_);
+    return *ptr_;
+  }
+
+  T* operator->() const {
+    assert(ptr_);
+    return ptr_;
+  }
+
+  T* get() const { return ptr_; }
+
+  /* If ref_donor is NULL, takes a new ref, otherwise adopts from ref_donor. */
+  template <class U>
+  void reset(U* ptr = NULL, const void* ref_donor = NULL) {
+    reffed_ptr(ptr, ref_donor).swap(*this);
+  }
+
+  template <class U>
+  reffed_ptr<U> down_cast() {
+    return reffed_ptr<U>(upb::down_cast<U*>(get()));
+  }
+
+  template <class U>
+  reffed_ptr<U> dyn_cast() {
+    return reffed_ptr<U>(upb::dyn_cast<U*>(get()));
+  }
+
+  /* Plain release() is unsafe; if we were the only owner, it would leak the
+   * object.  Instead we provide this: */
+  T* ReleaseTo(const void* new_owner) {
+    T* ret = NULL;
+    ptr_->DonateRef(this, new_owner);
+    std::swap(ret, ptr_);
+    return ret;
+  }
+
+ private:
+  T* ptr_;
+};
+
+#endif  /* __cplusplus */
+
 #endif  /* UPB_REFCOUNT_H_ */
 
 #ifdef __cplusplus
@@ -1265,12 +1654,17 @@ namespace upb {
 class Def;
 class EnumDef;
 class FieldDef;
+class FileDef;
 class MessageDef;
 class OneofDef;
 }
 #endif
 
 UPB_DECLARE_DERIVED_TYPE(upb::Def, upb::RefCounted, upb_def, upb_refcounted)
+UPB_DECLARE_DERIVED_TYPE(upb::OneofDef, upb::RefCounted, upb_oneofdef,
+                         upb_refcounted)
+UPB_DECLARE_DERIVED_TYPE(upb::FileDef, upb::RefCounted, upb_filedef,
+                         upb_refcounted)
 
 /* The maximum message depth that the type graph can have.  This is a resource
  * limit for the C stack since we sometimes need to recursively traverse the
@@ -1282,15 +1676,16 @@ UPB_DECLARE_DERIVED_TYPE(upb::Def, upb::RefCounted, upb_def, upb_refcounted)
 #define UPB_MAX_MESSAGE_DEPTH 64
 
 
-/* upb::Def: base class for defs  *********************************************/
+/* upb::Def: base class for top-level defs  ***********************************/
 
-/* All the different kind of defs we support.  These correspond 1:1 with
- * declarations in a .proto file. */
+/* All the different kind of defs that can be defined at the top-level and put
+ * in a SymbolTable or appear in a FileDef::defs() list.  This excludes some
+ * defs (like oneofs and files).  It only includes fields because they can be
+ * defined as extensions. */
 typedef enum {
   UPB_DEF_MSG,
   UPB_DEF_FIELD,
   UPB_DEF_ENUM,
-  UPB_DEF_ONEOF,
   UPB_DEF_SERVICE,   /* Not yet implemented. */
   UPB_DEF_ANY = -1   /* Wildcard for upb_symtab_get*() */
 } upb_deftype_t;
@@ -1313,6 +1708,9 @@ class upb::Def {
   /* "fullname" is the def's fully-qualified name (eg. foo.bar.Message). */
   const char *full_name() const;
 
+  /* The final part of a def's name (eg. Message). */
+  const char *name() const;
+
   /* The def must be mutable.  Caller retains ownership of fullname.  Defs are
    * not required to have a name; if a def has no name when it is frozen, it
    * will remain an anonymous def.  On failure, returns false and details in "s"
@@ -1320,6 +1718,11 @@ class upb::Def {
   bool set_full_name(const char* fullname, upb::Status* s);
   bool set_full_name(const std::string &fullname, upb::Status* s);
 
+  /* The file in which this def appears.  It is not necessary to add a def to a
+   * file (and consequently the accessor may return NULL).  Set this by calling
+   * file->Add(def). */
+  FileDef* file() const;
+
   /* Freezes the given defs; this validates all constraints and marks the defs
    * as frozen (read-only).  "defs" may not contain any fielddefs, but fields
    * of any msgdefs will be frozen.
@@ -1331,7 +1734,7 @@ class upb::Def {
    *
    * After this operation succeeds, the finalized defs must only be accessed
    * through a const pointer! */
-  static bool Freeze(Def* const* defs, int n, Status* status);
+  static bool Freeze(Def* const* defs, size_t n, Status* status);
   static bool Freeze(const std::vector<Def*>& defs, Status* status);
 
  private:
@@ -1350,8 +1753,13 @@ UPB_REFCOUNTED_CMETHODS(upb_def, upb_def_upcast)
 
 upb_deftype_t upb_def_type(const upb_def *d);
 const char *upb_def_fullname(const upb_def *d);
+const char *upb_def_name(const upb_def *d);
+const upb_filedef *upb_def_file(const upb_def *d);
 bool upb_def_setfullname(upb_def *def, const char *fullname, upb_status *s);
-bool upb_def_freeze(upb_def *const *defs, int n, upb_status *s);
+bool upb_def_freeze(upb_def *const *defs, size_t n, upb_status *s);
+
+/* Temporary API: for internal use only. */
+bool _upb_def_validate(upb_def *const*defs, size_t n, upb_status *s);
 
 UPB_END_EXTERN_C
 
@@ -1424,7 +1832,6 @@ UPB_END_EXTERN_C
 UPB_DECLARE_DEF_TYPE(upb::FieldDef, fielddef, FIELD)
 UPB_DECLARE_DEF_TYPE(upb::MessageDef, msgdef, MSG)
 UPB_DECLARE_DEF_TYPE(upb::EnumDef, enumdef, ENUM)
-UPB_DECLARE_DEF_TYPE(upb::OneofDef, oneofdef, ONEOF)
 
 #undef UPB_DECLARE_DEF_TYPE
 #undef UPB_DEF_CASTS
@@ -1487,6 +1894,11 @@ typedef enum {
   UPB_DESCRIPTOR_TYPE_SINT64   = 18
 } upb_descriptortype_t;
 
+typedef enum {
+  UPB_SYNTAX_PROTO2 = 2,
+  UPB_SYNTAX_PROTO3 = 3
+} upb_syntax_t;
+
 /* Maximum field number allowed for FieldDefs.  This is an inherent limit of the
  * protobuf wire format. */
 #define UPB_MAX_FIELDNUMBER ((1 << 29) - 1)
@@ -1582,7 +1994,7 @@ class upb::FieldDef {
    * whatever message this field belongs to.  Guaranteed to be less than
    * f->containing_type()->field_count().  May only be accessed once the def has
    * been finalized. */
-  int index() const;
+  uint32_t index() const;
 
   /* The MessageDef to which this field belongs.
    *
@@ -1878,6 +2290,10 @@ UPB_END_EXTERN_C
 typedef upb_inttable_iter upb_msg_field_iter;
 typedef upb_strtable_iter upb_msg_oneof_iter;
 
+/* Well-known field tag numbers for map-entry messages. */
+#define UPB_MAPENTRY_KEY   1
+#define UPB_MAPENTRY_VALUE 2
+
 #ifdef __cplusplus
 
 /* Structure that describes a single .proto message type.
@@ -1893,6 +2309,7 @@ class upb::MessageDef {
 
   /* Functionality from upb::Def. */
   const char* full_name() const;
+  const char* name() const;
   bool set_full_name(const char* fullname, Status* s);
   bool set_full_name(const std::string& fullname, Status* s);
 
@@ -1935,6 +2352,11 @@ class upb::MessageDef {
   bool AddOneof(OneofDef* o, Status* s);
   bool AddOneof(const reffed_ptr<OneofDef>& o, Status* s);
 
+  upb_syntax_t syntax() const;
+
+  /* Returns false if we don't support this syntax value. */
+  bool set_syntax(upb_syntax_t syntax);
+
   /* Set this to false to indicate that primitive fields should not have
    * explicit presence information associated with them.  This will affect all
    * fields added to this message.  Defaults to true. */
@@ -2125,15 +2547,20 @@ UPB_REFCOUNTED_CMETHODS(upb_msgdef, upb_msgdef_upcast2)
 
 bool upb_msgdef_freeze(upb_msgdef *m, upb_status *status);
 
+upb_msgdef *upb_msgdef_dup(const upb_msgdef *m, const void *owner);
 const char *upb_msgdef_fullname(const upb_msgdef *m);
-bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname, upb_status *s);
+const char *upb_msgdef_name(const upb_msgdef *m);
+int upb_msgdef_numoneofs(const upb_msgdef *m);
+upb_syntax_t upb_msgdef_syntax(const upb_msgdef *m);
 
-upb_msgdef *upb_msgdef_dup(const upb_msgdef *m, const void *owner);
 bool upb_msgdef_addfield(upb_msgdef *m, upb_fielddef *f, const void *ref_donor,
                          upb_status *s);
 bool upb_msgdef_addoneof(upb_msgdef *m, upb_oneofdef *o, const void *ref_donor,
                          upb_status *s);
-void upb_msgdef_setprimitiveshavepresence(upb_msgdef *m, bool have_presence);
+bool upb_msgdef_setfullname(upb_msgdef *m, const char *fullname, upb_status *s);
+void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry);
+bool upb_msgdef_mapentry(const upb_msgdef *m);
+bool upb_msgdef_setsyntax(upb_msgdef *m, upb_syntax_t syntax);
 
 /* Field lookup in a couple of different variations:
  *   - itof = int to field
@@ -2175,18 +2602,21 @@ UPB_INLINE upb_oneofdef *upb_msgdef_ntoo_mutable(upb_msgdef *m,
   return (upb_oneofdef *)upb_msgdef_ntoo(m, name, len);
 }
 
-void upb_msgdef_setmapentry(upb_msgdef *m, bool map_entry);
-bool upb_msgdef_mapentry(const upb_msgdef *m);
-
-/* Well-known field tag numbers for map-entry messages. */
-#define UPB_MAPENTRY_KEY   1
-#define UPB_MAPENTRY_VALUE 2
+/* Lookup of either field or oneof by name.  Returns whether either was found.
+ * If the return is true, then the found def will be set, and the non-found
+ * one set to NULL. */
+bool upb_msgdef_lookupname(const upb_msgdef *m, const char *name, size_t len,
+                           const upb_fielddef **f, const upb_oneofdef **o);
 
-const upb_oneofdef *upb_msgdef_findoneof(const upb_msgdef *m,
-                                          const char *name);
-int upb_msgdef_numoneofs(const upb_msgdef *m);
+UPB_INLINE bool upb_msgdef_lookupnamez(const upb_msgdef *m, const char *name,
+                                       const upb_fielddef **f,
+                                       const upb_oneofdef **o) {
+  return upb_msgdef_lookupname(m, name, strlen(name), f, o);
+}
 
-/* upb_msg_field_iter i;
+/* Iteration over fields and oneofs.  For example:
+ *
+ * upb_msg_field_iter i;
  * for(upb_msg_field_begin(&i, m);
  *     !upb_msg_field_done(&i);
  *     upb_msg_field_next(&i)) {
@@ -2232,6 +2662,7 @@ class upb::EnumDef {
 
   /* Functionality from upb::Def. */
   const char* full_name() const;
+  const char* name() const;
   bool set_full_name(const char* fullname, Status* s);
   bool set_full_name(const std::string& fullname, Status* s);
 
@@ -2306,6 +2737,7 @@ bool upb_enumdef_freeze(upb_enumdef *e, upb_status *status);
 
 /* From upb_def. */
 const char *upb_enumdef_fullname(const upb_enumdef *e);
+const char *upb_enumdef_name(const upb_enumdef *e);
 bool upb_enumdef_setfullname(upb_enumdef *e, const char *fullname,
                              upb_status *s);
 
@@ -2347,8 +2779,7 @@ typedef upb_inttable_iter upb_oneof_iter;
 
 #ifdef __cplusplus
 
-/* Class that represents a oneof.  Its base class is upb::Def (convert with
- * upb::upcast()). */
+/* Class that represents a oneof. */
 class upb::OneofDef {
  public:
   /* Returns NULL if memory allocation failed. */
@@ -2357,9 +2788,6 @@ class upb::OneofDef {
   /* upb::RefCounted methods like Ref()/Unref(). */
   UPB_REFCOUNTED_CPPMETHODS
 
-  /* Functionality from upb::Def. */
-  const char* full_name() const;
-
   /* Returns the MessageDef that owns this OneofDef. */
   const MessageDef* containing_type() const;
 
@@ -2367,6 +2795,7 @@ class upb::OneofDef {
    * by name once added to a message def. */
   const char* name() const;
   bool set_name(const char* name, Status* s);
+  bool set_name(const std::string& name, Status* s);
 
   /* Returns the number of fields currently defined in the oneof. */
   int field_count() const;
@@ -2460,7 +2889,7 @@ upb_oneofdef *upb_oneofdef_new(const void *owner);
 upb_oneofdef *upb_oneofdef_dup(const upb_oneofdef *o, const void *owner);
 
 /* Include upb_refcounted methods like upb_oneofdef_ref(). */
-UPB_REFCOUNTED_CMETHODS(upb_oneofdef, upb_oneofdef_upcast2)
+UPB_REFCOUNTED_CMETHODS(upb_oneofdef, upb_oneofdef_upcast)
 
 const char *upb_oneofdef_name(const upb_oneofdef *o);
 bool upb_oneofdef_setname(upb_oneofdef *o, const char *name, upb_status *s);
@@ -2496,6 +2925,120 @@ void upb_oneof_iter_setdone(upb_oneof_iter *iter);
 
 UPB_END_EXTERN_C
 
+
+/* upb::FileDef ***************************************************************/
+
+#ifdef __cplusplus
+
+/* Class that represents a .proto file with some things defined in it.
+ *
+ * Many users won't care about FileDefs, but they are necessary if you want to
+ * read the values of file-level options. */
+class upb::FileDef {
+ public:
+  /* Returns NULL if memory allocation failed. */
+  static reffed_ptr<FileDef> New();
+
+  /* upb::RefCounted methods like Ref()/Unref(). */
+  UPB_REFCOUNTED_CPPMETHODS
+
+  /* Get/set name of the file (eg. "foo/bar.proto"). */
+  const char* name() const;
+  bool set_name(const char* name, Status* s);
+  bool set_name(const std::string& name, Status* s);
+
+  /* Package name for definitions inside the file (eg. "foo.bar"). */
+  const char* package() const;
+  bool set_package(const char* package, Status* s);
+
+  /* Syntax for the file.  Defaults to proto2. */
+  upb_syntax_t syntax() const;
+  void set_syntax(upb_syntax_t syntax);
+
+  /* Get the list of defs from the file.  These are returned in the order that
+   * they were added to the FileDef. */
+  int def_count() const;
+  const Def* def(int index) const;
+  Def* def(int index);
+
+  /* Get the list of dependencies from the file.  These are returned in the
+   * order that they were added to the FileDef. */
+  int dependency_count() const;
+  const FileDef* dependency(int index) const;
+
+  /* Adds defs to this file.  The def must not already belong to another
+   * file.
+   *
+   * Note: this does *not* ensure that this def's name is unique in this file!
+   * Use a SymbolTable if you want to check this property.  Especially since
+   * properly checking uniqueness would require a check across *all* files
+   * (including dependencies). */
+  bool AddDef(Def* def, Status* s);
+  bool AddMessage(MessageDef* m, Status* s);
+  bool AddEnum(EnumDef* e, Status* s);
+  bool AddExtension(FieldDef* f, Status* s);
+
+  /* Adds a dependency of this file. */
+  bool AddDependency(const FileDef* file);
+
+  /* Freezes this FileDef and all messages/enums under it.  All subdefs must be
+   * resolved and all messages/enums must validate.  Returns true if this
+   * succeeded.
+   *
+   * TODO(haberman): should we care whether the file's dependencies are frozen
+   * already? */
+  bool Freeze(Status* s);
+
+ private:
+  UPB_DISALLOW_POD_OPS(FileDef, upb::FileDef)
+};
+
+#endif
+
+UPB_BEGIN_EXTERN_C
+
+upb_filedef *upb_filedef_new(const void *owner);
+
+/* Include upb_refcounted methods like upb_msgdef_ref(). */
+UPB_REFCOUNTED_CMETHODS(upb_filedef, upb_filedef_upcast)
+
+const char *upb_filedef_name(const upb_filedef *f);
+const char *upb_filedef_package(const upb_filedef *f);
+upb_syntax_t upb_filedef_syntax(const upb_filedef *f);
+size_t upb_filedef_defcount(const upb_filedef *f);
+size_t upb_filedef_depcount(const upb_filedef *f);
+const upb_def *upb_filedef_def(const upb_filedef *f, size_t i);
+const upb_filedef *upb_filedef_dep(const upb_filedef *f, size_t i);
+
+bool upb_filedef_freeze(upb_filedef *f, upb_status *s);
+bool upb_filedef_setname(upb_filedef *f, const char *name, upb_status *s);
+bool upb_filedef_setpackage(upb_filedef *f, const char *package, upb_status *s);
+bool upb_filedef_setsyntax(upb_filedef *f, upb_syntax_t syntax, upb_status *s);
+
+bool upb_filedef_adddef(upb_filedef *f, upb_def *def, const void *ref_donor,
+                        upb_status *s);
+bool upb_filedef_adddep(upb_filedef *f, const upb_filedef *dep);
+
+UPB_INLINE bool upb_filedef_addmsg(upb_filedef *f, upb_msgdef *m,
+                                   const void *ref_donor, upb_status *s) {
+  return upb_filedef_adddef(f, upb_msgdef_upcast_mutable(m), ref_donor, s);
+}
+
+UPB_INLINE bool upb_filedef_addenum(upb_filedef *f, upb_enumdef *e,
+                                    const void *ref_donor, upb_status *s) {
+  return upb_filedef_adddef(f, upb_enumdef_upcast_mutable(e), ref_donor, s);
+}
+
+UPB_INLINE bool upb_filedef_addext(upb_filedef *file, upb_fielddef *f,
+                                   const void *ref_donor, upb_status *s) {
+  return upb_filedef_adddef(file, upb_fielddef_upcast_mutable(f), ref_donor, s);
+}
+UPB_INLINE upb_def *upb_filedef_mutabledef(upb_filedef *f, int i) {
+  return (upb_def*)upb_filedef_def(f, i);
+}
+
+UPB_END_EXTERN_C
+
 #ifdef __cplusplus
 
 UPB_INLINE const char* upb_safecstr(const std::string& str) {
@@ -2511,13 +3054,14 @@ inline Def* Def::Dup(const void* owner) const {
 }
 inline Def::Type Def::def_type() const { return upb_def_type(this); }
 inline const char* Def::full_name() const { return upb_def_fullname(this); }
+inline const char* Def::name() const { return upb_def_name(this); }
 inline bool Def::set_full_name(const char* fullname, Status* s) {
   return upb_def_setfullname(this, fullname, s);
 }
 inline bool Def::set_full_name(const std::string& fullname, Status* s) {
   return upb_def_setfullname(this, upb_safecstr(fullname), s);
 }
-inline bool Def::Freeze(Def* const* defs, int n, Status* status) {
+inline bool Def::Freeze(Def* const* defs, size_t n, Status* status) {
   return upb_def_freeze(defs, n, status);
 }
 inline bool Def::Freeze(const std::vector<Def*>& defs, Status* status) {
@@ -2596,6 +3140,9 @@ inline void FieldDef::set_lazy(bool lazy) {
 inline bool FieldDef::packed() const {
   return upb_fielddef_packed(this);
 }
+inline uint32_t FieldDef::index() const {
+  return upb_fielddef_index(this);
+}
 inline void FieldDef::set_packed(bool packed) {
   upb_fielddef_setpacked(this, packed);
 }
@@ -2740,12 +3287,21 @@ inline reffed_ptr<MessageDef> MessageDef::New() {
 inline const char *MessageDef::full_name() const {
   return upb_msgdef_fullname(this);
 }
+inline const char *MessageDef::name() const {
+  return upb_msgdef_name(this);
+}
+inline upb_syntax_t MessageDef::syntax() const {
+  return upb_msgdef_syntax(this);
+}
 inline bool MessageDef::set_full_name(const char* fullname, Status* s) {
   return upb_msgdef_setfullname(this, fullname, s);
 }
 inline bool MessageDef::set_full_name(const std::string& fullname, Status* s) {
   return upb_msgdef_setfullname(this, upb_safecstr(fullname), s);
 }
+inline bool MessageDef::set_syntax(upb_syntax_t syntax) {
+  return upb_msgdef_setsyntax(this, syntax);
+}
 inline bool MessageDef::Freeze(Status* status) {
   return upb_msgdef_freeze(this, status);
 }
@@ -2927,6 +3483,9 @@ inline reffed_ptr<EnumDef> EnumDef::New() {
 inline const char* EnumDef::full_name() const {
   return upb_enumdef_fullname(this);
 }
+inline const char* EnumDef::name() const {
+  return upb_enumdef_name(this);
+}
 inline bool EnumDef::set_full_name(const char* fullname, Status* s) {
   return upb_enumdef_setfullname(this, fullname, s);
 }
@@ -2976,9 +3535,6 @@ inline reffed_ptr<OneofDef> OneofDef::New() {
   upb_oneofdef *o = upb_oneofdef_new(&o);
   return reffed_ptr<OneofDef>(o, &o);
 }
-inline const char* OneofDef::full_name() const {
-  return upb_oneofdef_name(this);
-}
 
 inline const MessageDef* OneofDef::containing_type() const {
   return upb_oneofdef_containingtype(this);
@@ -2989,6 +3545,9 @@ inline const char* OneofDef::name() const {
 inline bool OneofDef::set_name(const char* name, Status* s) {
   return upb_oneofdef_setname(this, name, s);
 }
+inline bool OneofDef::set_name(const std::string& name, Status* s) {
+  return upb_oneofdef_setname(this, upb_safecstr(name), s);
+}
 inline int OneofDef::field_count() const {
   return upb_oneofdef_numfields(this);
 }
@@ -3057,6 +3616,57 @@ inline bool OneofDef::const_iterator::operator!=(
   return !(*this == other);
 }
 
+inline reffed_ptr<FileDef> FileDef::New() {
+  upb_filedef *f = upb_filedef_new(&f);
+  return reffed_ptr<FileDef>(f, &f);
+}
+
+inline const char* FileDef::name() const {
+  return upb_filedef_name(this);
+}
+inline bool FileDef::set_name(const char* name, Status* s) {
+  return upb_filedef_setname(this, name, s);
+}
+inline bool FileDef::set_name(const std::string& name, Status* s) {
+  return upb_filedef_setname(this, upb_safecstr(name), s);
+}
+inline const char* FileDef::package() const {
+  return upb_filedef_package(this);
+}
+inline bool FileDef::set_package(const char* package, Status* s) {
+  return upb_filedef_setpackage(this, package, s);
+}
+inline int FileDef::def_count() const {
+  return upb_filedef_defcount(this);
+}
+inline const Def* FileDef::def(int index) const {
+  return upb_filedef_def(this, index);
+}
+inline Def* FileDef::def(int index) {
+  return const_cast<Def*>(upb_filedef_def(this, index));
+}
+inline int FileDef::dependency_count() const {
+  return upb_filedef_depcount(this);
+}
+inline const FileDef* FileDef::dependency(int index) const {
+  return upb_filedef_dep(this, index);
+}
+inline bool FileDef::AddDef(Def* def, Status* s) {
+  return upb_filedef_adddef(this, def, NULL, s);
+}
+inline bool FileDef::AddMessage(MessageDef* m, Status* s) {
+  return upb_filedef_addmsg(this, m, NULL, s);
+}
+inline bool FileDef::AddEnum(EnumDef* e, Status* s) {
+  return upb_filedef_addenum(this, e, NULL, s);
+}
+inline bool FileDef::AddExtension(FieldDef* f, Status* s) {
+  return upb_filedef_addext(this, f, NULL, s);
+}
+inline bool FileDef::AddDependency(const FileDef* file) {
+  return upb_filedef_adddep(this, file);
+}
+
 }  /* namespace upb */
 #endif
 
@@ -3095,6 +3705,7 @@ struct upb_def {
   upb_refcounted base;
 
   const char *fullname;
+  const upb_filedef* file;
   char type;  /* A upb_deftype_t (char to save space) */
 
   /* Used as a flag during the def's mutable stage.  Must be false unless
@@ -3104,8 +3715,8 @@ struct upb_def {
   bool came_from_user;
 };
 
-#define UPB_DEF_INIT(name, type, refs, ref2s) \
-    { UPB_REFCOUNT_INIT(refs, ref2s), name, type, false }
+#define UPB_DEF_INIT(name, type, vtbl, refs, ref2s) \
+    { UPB_REFCOUNT_INIT(vtbl, refs, ref2s), name, NULL, type, false }
 
 
 /* upb_fielddef ***************************************************************/
@@ -3145,12 +3756,14 @@ struct upb_fielddef {
   uint32_t index_;
 };
 
+extern const struct upb_refcounted_vtbl upb_fielddef_vtbl;
+
 #define UPB_FIELDDEF_INIT(label, type, intfmt, tagdelim, is_extension, lazy,   \
                           packed, name, num, msgdef, subdef, selector_base,    \
                           index, defaultval, refs, ref2s)                      \
   {                                                                            \
-    UPB_DEF_INIT(name, UPB_DEF_FIELD, refs, ref2s), defaultval, {msgdef},      \
-        {subdef}, NULL, false, false,                                          \
+    UPB_DEF_INIT(name, UPB_DEF_FIELD, &upb_fielddef_vtbl, refs, ref2s),        \
+        defaultval, {msgdef}, {subdef}, NULL, false, false,                    \
         type == UPB_TYPE_STRING || type == UPB_TYPE_BYTES, true, is_extension, \
         lazy, packed, intfmt, tagdelim, type, label, num, selector_base, index \
   }
@@ -3166,32 +3779,26 @@ struct upb_msgdef {
 
   /* Tables for looking up fields by number and name. */
   upb_inttable itof;  /* int to field */
-  upb_strtable ntof;  /* name to field */
+  upb_strtable ntof;  /* name to field/oneof */
 
-  /* Tables for looking up oneofs by name. */
-  upb_strtable ntoo;  /* name to oneof */
-
-  /* Is this a map-entry message?
-   * TODO: set this flag properly for static descriptors; regenerate
-   * descriptor.upb.c. */
+  /* Is this a map-entry message? */
   bool map_entry;
 
-  /* Do primitive values in this message have explicit presence or not?
-   * TODO: set this flag properly for static descriptors; regenerate
-   * descriptor.upb.c. */
-  bool primitives_have_presence;
+  /* Whether this message has proto2 or proto3 semantics. */
+  upb_syntax_t syntax;
 
   /* TODO(haberman): proper extension ranges (there can be multiple). */
 };
 
+extern const struct upb_refcounted_vtbl upb_msgdef_vtbl;
+
 /* TODO: also support static initialization of the oneofs table. This will be
  * needed if we compile in descriptors that contain oneofs. */
 #define UPB_MSGDEF_INIT(name, selector_count, submsg_field_count, itof, ntof, \
-                        refs, ref2s)                                          \
+                        map_entry, syntax, refs, ref2s)                       \
   {                                                                           \
-    UPB_DEF_INIT(name, UPB_DEF_MSG, refs, ref2s), selector_count,             \
-        submsg_field_count, itof, ntof,                                       \
-        UPB_EMPTY_STRTABLE_INIT(UPB_CTYPE_PTR), false, true                   \
+    UPB_DEF_INIT(name, UPB_DEF_MSG, &upb_fielddef_vtbl, refs, ref2s),         \
+        selector_count, submsg_field_count, itof, ntof, map_entry, syntax     \
   }
 
 
@@ -3205,22 +3812,28 @@ struct upb_enumdef {
   int32_t defaultval;
 };
 
+extern const struct upb_refcounted_vtbl upb_enumdef_vtbl;
+
 #define UPB_ENUMDEF_INIT(name, ntoi, iton, defaultval, refs, ref2s) \
-  { UPB_DEF_INIT(name, UPB_DEF_ENUM, refs, ref2s), ntoi, iton, defaultval }
+  { UPB_DEF_INIT(name, UPB_DEF_ENUM, &upb_enumdef_vtbl, refs, ref2s), ntoi,    \
+    iton, defaultval }
 
 
 /* upb_oneofdef ***************************************************************/
 
 struct upb_oneofdef {
-  upb_def base;
+  upb_refcounted base;
 
+  const char *name;
   upb_strtable ntof;
   upb_inttable itof;
   const upb_msgdef *parent;
 };
 
+extern const struct upb_refcounted_vtbl upb_oneofdef_vtbl;
+
 #define UPB_ONEOFDEF_INIT(name, ntof, itof, refs, ref2s) \
-  { UPB_DEF_INIT(name, UPB_DEF_ENUM, refs, ref2s), ntof, itof }
+  { UPB_REFCOUNT_INIT(&upb_oneofdef_vtbl, refs, ref2s), name, ntof, itof }
 
 
 /* upb_symtab *****************************************************************/
@@ -3231,9 +3844,18 @@ struct upb_symtab {
   upb_strtable symtab;
 };
 
-#define UPB_SYMTAB_INIT(symtab, refs, ref2s) \
-  { UPB_REFCOUNT_INIT(refs, ref2s), symtab }
+struct upb_filedef {
+  upb_refcounted base;
 
+  const char *name;
+  const char *package;
+  upb_syntax_t syntax;
+
+  upb_inttable defs;
+  upb_inttable deps;
+};
+
+extern const struct upb_refcounted_vtbl upb_filedef_vtbl;
 
 #endif  /* UPB_STATICINIT_H_ */
 /*
@@ -5176,267 +5798,6 @@ inline BytesHandler::~BytesHandler() {}
 
 #endif  /* UPB_HANDLERS_H */
 /*
-** upb::Environment (upb_env)
-**
-** A upb::Environment provides a means for injecting malloc and an
-** error-reporting callback into encoders/decoders.  This allows them to be
-** independent of nearly all assumptions about their actual environment.
-**
-** It is also a container for allocating the encoders/decoders themselves that
-** insulates clients from knowing their actual size.  This provides ABI
-** compatibility even if the size of the objects change.  And this allows the
-** structure definitions to be in the .c files instead of the .h files, making
-** the .h files smaller and more readable.
-*/
-
-
-#ifndef UPB_ENV_H_
-#define UPB_ENV_H_
-
-#ifdef __cplusplus
-namespace upb {
-class Environment;
-class SeededAllocator;
-}
-#endif
-
-UPB_DECLARE_TYPE(upb::Environment, upb_env)
-UPB_DECLARE_TYPE(upb::SeededAllocator, upb_seededalloc)
-
-typedef void *upb_alloc_func(void *ud, void *ptr, size_t oldsize, size_t size);
-typedef void upb_cleanup_func(void *ud);
-typedef bool upb_error_func(void *ud, const upb_status *status);
-
-#ifdef __cplusplus
-
-/* An environment is *not* thread-safe. */
-class upb::Environment {
- public:
-  Environment();
-  ~Environment();
-
-  /* Set a custom memory allocation function for the environment.  May ONLY
-   * be called before any calls to Malloc()/Realloc()/AddCleanup() below.
-   * If this is not called, the system realloc() function will be used.
-   * The given user pointer "ud" will be passed to the allocation function.
-   *
-   * The allocation function will not receive corresponding "free" calls.  it
-   * must ensure that the memory is valid for the lifetime of the Environment,
-   * but it may be reclaimed any time thereafter.  The likely usage is that
-   * "ud" points to a stateful allocator, and that the allocator frees all
-   * memory, arena-style, when it is destroyed.  In this case the allocator must
-   * outlive the Environment.  Another possibility is that the allocation
-   * function returns GC-able memory that is guaranteed to be GC-rooted for the
-   * life of the Environment. */
-  void SetAllocationFunction(upb_alloc_func* alloc, void* ud);
-
-  template<class T>
-  void SetAllocator(T* allocator) {
-    SetAllocationFunction(allocator->GetAllocationFunction(), allocator);
-  }
-
-  /* Set a custom error reporting function. */
-  void SetErrorFunction(upb_error_func* func, void* ud);
-
-  /* Set the error reporting function to simply copy the status to the given
-   * status and abort. */
-  void ReportErrorsTo(Status* status);
-
-  /* Returns true if all allocations and AddCleanup() calls have succeeded,
-   * and no errors were reported with ReportError() (except ones that recovered
-   * successfully). */
-  bool ok() const;
-
-  /* Functions for use by encoders/decoders. **********************************/
-
-  /* Reports an error to this environment's callback, returning true if
-   * the caller should try to recover. */
-  bool ReportError(const Status* status);
-
-  /* Allocate memory.  Uses the environment's allocation function.
-   *
-   * There is no need to free(). All memory will be freed automatically, but is
-   * guaranteed to outlive the Environment. */
-  void* Malloc(size_t size);
-
-  /* Reallocate memory.  Preserves "oldsize" bytes from the existing buffer
-   * Requires: oldsize <= existing_size.
-   *
-   * TODO(haberman): should we also enforce that oldsize <= size? */
-  void* Realloc(void* ptr, size_t oldsize, size_t size);
-
-  /* Add a cleanup function to run when the environment is destroyed.
-   * Returns false on out-of-memory.
-   *
-   * The first call to AddCleanup() after SetAllocationFunction() is guaranteed
-   * to return true -- this makes it possible to robustly set a cleanup handler
-   * for a custom allocation function. */
-  bool AddCleanup(upb_cleanup_func* func, void* ud);
-
-  /* Total number of bytes that have been allocated.  It is undefined what
-   * Realloc() does to this counter. */
-  size_t BytesAllocated() const;
-
- private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(Environment)
-
-#else
-struct upb_env {
-#endif  /* __cplusplus */
-
-  bool ok_;
-  size_t bytes_allocated;
-
-  /* Alloc function. */
-  upb_alloc_func *alloc;
-  void *alloc_ud;
-
-  /* Error-reporting function. */
-  upb_error_func *err;
-  void *err_ud;
-
-  /* Userdata for default alloc func. */
-  void *default_alloc_ud;
-
-  /* Cleanup entries.  Pointer to a cleanup_ent, defined in env.c */
-  void *cleanup_head;
-
-  /* For future expansion, since the size of this struct is exposed to users. */
-  void *future1;
-  void *future2;
-};
-
-UPB_BEGIN_EXTERN_C
-
-void upb_env_init(upb_env *e);
-void upb_env_uninit(upb_env *e);
-void upb_env_setallocfunc(upb_env *e, upb_alloc_func *func, void *ud);
-void upb_env_seterrorfunc(upb_env *e, upb_error_func *func, void *ud);
-void upb_env_reporterrorsto(upb_env *e, upb_status *status);
-bool upb_env_ok(const upb_env *e);
-bool upb_env_reporterror(upb_env *e, const upb_status *status);
-void *upb_env_malloc(upb_env *e, size_t size);
-void *upb_env_realloc(upb_env *e, void *ptr, size_t oldsize, size_t size);
-bool upb_env_addcleanup(upb_env *e, upb_cleanup_func *func, void *ud);
-size_t upb_env_bytesallocated(const upb_env *e);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-/* An allocator that allocates from an initial memory region (likely the stack)
- * before falling back to another allocator. */
-class upb::SeededAllocator {
- public:
-  SeededAllocator(void *mem, size_t len);
-  ~SeededAllocator();
-
-  /* Set a custom fallback memory allocation function for the allocator, to use
-   * once the initial region runs out.
-   *
-   * May ONLY be called before GetAllocationFunction().  If this is not
-   * called, the system realloc() will be the fallback allocator. */
-  void SetFallbackAllocator(upb_alloc_func *alloc, void *ud);
-
-  /* Gets the allocation function for this allocator. */
-  upb_alloc_func* GetAllocationFunction();
-
- private:
-  UPB_DISALLOW_COPY_AND_ASSIGN(SeededAllocator)
-
-#else
-struct upb_seededalloc {
-#endif  /* __cplusplus */
-
-  /* Fallback alloc function.  */
-  upb_alloc_func *alloc;
-  upb_cleanup_func *alloc_cleanup;
-  void *alloc_ud;
-  bool need_cleanup;
-  bool returned_allocfunc;
-
-  /* Userdata for default alloc func. */
-  void *default_alloc_ud;
-
-  /* Pointers for the initial memory region. */
-  char *mem_base;
-  char *mem_ptr;
-  char *mem_limit;
-
-  /* For future expansion, since the size of this struct is exposed to users. */
-  void *future1;
-  void *future2;
-};
-
-UPB_BEGIN_EXTERN_C
-
-void upb_seededalloc_init(upb_seededalloc *a, void *mem, size_t len);
-void upb_seededalloc_uninit(upb_seededalloc *a);
-void upb_seededalloc_setfallbackalloc(upb_seededalloc *a, upb_alloc_func *func,
-                                      void *ud);
-upb_alloc_func *upb_seededalloc_getallocfunc(upb_seededalloc *a);
-
-UPB_END_EXTERN_C
-
-#ifdef __cplusplus
-
-namespace upb {
-
-inline Environment::Environment() {
-  upb_env_init(this);
-}
-inline Environment::~Environment() {
-  upb_env_uninit(this);
-}
-inline void Environment::SetAllocationFunction(upb_alloc_func *alloc,
-                                               void *ud) {
-  upb_env_setallocfunc(this, alloc, ud);
-}
-inline void Environment::SetErrorFunction(upb_error_func *func, void *ud) {
-  upb_env_seterrorfunc(this, func, ud);
-}
-inline void Environment::ReportErrorsTo(Status* status) {
-  upb_env_reporterrorsto(this, status);
-}
-inline bool Environment::ok() const {
-  return upb_env_ok(this);
-}
-inline bool Environment::ReportError(const Status* status) {
-  return upb_env_reporterror(this, status);
-}
-inline void *Environment::Malloc(size_t size) {
-  return upb_env_malloc(this, size);
-}
-inline void *Environment::Realloc(void *ptr, size_t oldsize, size_t size) {
-  return upb_env_realloc(this, ptr, oldsize, size);
-}
-inline bool Environment::AddCleanup(upb_cleanup_func *func, void *ud) {
-  return upb_env_addcleanup(this, func, ud);
-}
-inline size_t Environment::BytesAllocated() const {
-  return upb_env_bytesallocated(this);
-}
-
-inline SeededAllocator::SeededAllocator(void *mem, size_t len) {
-  upb_seededalloc_init(this, mem, len);
-}
-inline SeededAllocator::~SeededAllocator() {
-  upb_seededalloc_uninit(this);
-}
-inline void SeededAllocator::SetFallbackAllocator(upb_alloc_func *alloc,
-                                                  void *ud) {
-  upb_seededalloc_setfallbackalloc(this, alloc, ud);
-}
-inline upb_alloc_func *SeededAllocator::GetAllocationFunction() {
-  return upb_seededalloc_getallocfunc(this);
-}
-
-}  /* namespace upb */
-
-#endif  /* __cplusplus */
-
-#endif  /* UPB_ENV_H_ */
-/*
 ** upb::Sink (upb_sink)
 ** upb::BytesSink (upb_bytessink)
 **
@@ -6140,12 +6501,17 @@ class upb::SymbolTable {
    * only a few messages are changing.  We may want to add a way of adding a
    * tree of frozen defs to the symtab (perhaps an alternate constructor where
    * you pass the root of the tree?) */
-  bool Add(Def*const* defs, int n, void* ref_donor, upb_status* status);
+  bool Add(Def*const* defs, size_t n, void* ref_donor, Status* status);
 
   bool Add(const std::vector<Def*>& defs, void *owner, Status* status) {
     return Add((Def*const*)&defs[0], defs.size(), owner, status);
   }
 
+  /* Resolves all subdefs for messages in this file and attempts to freeze the
+   * file.  If this succeeds, adds all the symbols to this SymbolTable
+   * (replacing any existing ones with the same names). */
+  bool AddFile(FileDef* file, Status* s);
+
  private:
   UPB_DISALLOW_POD_OPS(SymbolTable, upb::SymbolTable)
 };
@@ -6166,8 +6532,9 @@ const upb_def *upb_symtab_resolve(const upb_symtab *s, const char *base,
 const upb_def *upb_symtab_lookup(const upb_symtab *s, const char *sym);
 const upb_msgdef *upb_symtab_lookupmsg(const upb_symtab *s, const char *sym);
 const upb_enumdef *upb_symtab_lookupenum(const upb_symtab *s, const char *sym);
-bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, int n, void *ref_donor,
-                    upb_status *status);
+bool upb_symtab_add(upb_symtab *s, upb_def *const*defs, size_t n,
+                    void *ref_donor, upb_status *status);
+bool upb_symtab_addfile(upb_symtab *s, upb_filedef *file, upb_status* status);
 
 /* upb_symtab_iter i;
  * for(upb_symtab_begin(&i, s, type); !upb_symtab_done(&i);
@@ -6209,9 +6576,12 @@ inline const MessageDef *SymbolTable::LookupMessage(const char *sym) const {
   return upb_symtab_lookupmsg(this, sym);
 }
 inline bool SymbolTable::Add(
-    Def*const* defs, int n, void* ref_donor, upb_status* status) {
+    Def*const* defs, size_t n, void* ref_donor, Status* status) {
   return upb_symtab_add(this, (upb_def*const*)defs, n, ref_donor, status);
 }
+inline bool SymbolTable::AddFile(FileDef* file, Status* s) {
+  return upb_symtab_addfile(this, file, s);
+}
 }  /* namespace upb */
 #endif
 
@@ -6255,14 +6625,9 @@ class upb::descriptor::Reader {
   /* The reader's input; this is where descriptor.proto data should be sent. */
   Sink* input();
 
-  /* Returns an array of all defs that have been parsed, and transfers ownership
-   * of them to "owner".  The number of defs is stored in *n.  Ownership of the
-   * returned array is retained and is invalidated by any other call into
-   * Reader.
-   *
-   * These defs are not frozen or resolved; they are ready to be added to a
-   * symtab. */
-  upb::Def** GetDefs(void* owner, int* n);
+  /* Use to get the FileDefs that have been parsed. */
+  size_t file_count() const;
+  FileDef* file(size_t i) const;
 
   /* Builds and returns handlers for the reader, owned by "owner." */
   static Handlers* NewHandlers(const void* owner);
@@ -6278,7 +6643,8 @@ UPB_BEGIN_EXTERN_C
 /* C API. */
 upb_descreader *upb_descreader_create(upb_env *e, const upb_handlers *h);
 upb_sink *upb_descreader_input(upb_descreader *r);
-upb_def **upb_descreader_getdefs(upb_descreader *r, void *owner, int *n);
+size_t upb_descreader_filecount(const upb_descreader *r);
+upb_filedef *upb_descreader_file(const upb_descreader *r, size_t i);
 const upb_handlers *upb_descreader_newhandlers(const void *owner);
 
 UPB_END_EXTERN_C
@@ -6291,8 +6657,11 @@ inline Reader* Reader::Create(Environment* e, const Handlers *h) {
   return upb_descreader_create(e, h);
 }
 inline Sink* Reader::input() { return upb_descreader_input(this); }
-inline upb::Def** Reader::GetDefs(void* owner, int* n) {
-  return upb_descreader_getdefs(this, owner, n);
+inline size_t Reader::file_count() const {
+  return upb_descreader_filecount(this);
+}
+inline FileDef* Reader::file(size_t i) const {
+  return upb_descreader_file(this, i);
 }
 }  /* namespace descriptor */
 }  /* namespace upb */
@@ -6305,614 +6674,290 @@ inline upb::Def** Reader::GetDefs(void* owner, int* n) {
  * actually storing protobufs.  It only contains *defs* which
  * let you reflect over a protobuf *schema*.
  */
-/* This file was generated by upbc (the upb compiler).
+/* This file was generated by upbc (the upb compiler) from the input
+ * file:
+ *
+ *     upb/descriptor/descriptor.proto
+ *
  * Do not edit -- your changes will be discarded when the file is
  * regenerated. */
 
-#ifndef GOOGLE_PROTOBUF_DESCRIPTOR_UPB_H_
-#define GOOGLE_PROTOBUF_DESCRIPTOR_UPB_H_
+#ifndef UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_
+#define UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_
 
 
-#ifdef __cplusplus
 UPB_BEGIN_EXTERN_C
-#endif
 
 /* Enums */
 
 typedef enum {
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_LABEL_OPTIONAL = 1,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_LABEL_REQUIRED = 2,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_LABEL_REPEATED = 3
+  google_protobuf_FieldDescriptorProto_LABEL_OPTIONAL = 1,
+  google_protobuf_FieldDescriptorProto_LABEL_REQUIRED = 2,
+  google_protobuf_FieldDescriptorProto_LABEL_REPEATED = 3
 } google_protobuf_FieldDescriptorProto_Label;
 
 typedef enum {
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_DOUBLE = 1,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FLOAT = 2,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_INT64 = 3,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_UINT64 = 4,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_INT32 = 5,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FIXED64 = 6,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_FIXED32 = 7,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BOOL = 8,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_STRING = 9,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_GROUP = 10,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_MESSAGE = 11,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_BYTES = 12,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_UINT32 = 13,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_ENUM = 14,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SFIXED32 = 15,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SFIXED64 = 16,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SINT32 = 17,
-  GOOGLE_PROTOBUF_FIELDDESCRIPTORPROTO_TYPE_SINT64 = 18
+  google_protobuf_FieldDescriptorProto_TYPE_DOUBLE = 1,
+  google_protobuf_FieldDescriptorProto_TYPE_FLOAT = 2,
+  google_protobuf_FieldDescriptorProto_TYPE_INT64 = 3,
+  google_protobuf_FieldDescriptorProto_TYPE_UINT64 = 4,
+  google_protobuf_FieldDescriptorProto_TYPE_INT32 = 5,
+  google_protobuf_FieldDescriptorProto_TYPE_FIXED64 = 6,
+  google_protobuf_FieldDescriptorProto_TYPE_FIXED32 = 7,
+  google_protobuf_FieldDescriptorProto_TYPE_BOOL = 8,
+  google_protobuf_FieldDescriptorProto_TYPE_STRING = 9,
+  google_protobuf_FieldDescriptorProto_TYPE_GROUP = 10,
+  google_protobuf_FieldDescriptorProto_TYPE_MESSAGE = 11,
+  google_protobuf_FieldDescriptorProto_TYPE_BYTES = 12,
+  google_protobuf_FieldDescriptorProto_TYPE_UINT32 = 13,
+  google_protobuf_FieldDescriptorProto_TYPE_ENUM = 14,
+  google_protobuf_FieldDescriptorProto_TYPE_SFIXED32 = 15,
+  google_protobuf_FieldDescriptorProto_TYPE_SFIXED64 = 16,
+  google_protobuf_FieldDescriptorProto_TYPE_SINT32 = 17,
+  google_protobuf_FieldDescriptorProto_TYPE_SINT64 = 18
 } google_protobuf_FieldDescriptorProto_Type;
 
 typedef enum {
-  GOOGLE_PROTOBUF_FIELDOPTIONS_STRING = 0,
-  GOOGLE_PROTOBUF_FIELDOPTIONS_CORD = 1,
-  GOOGLE_PROTOBUF_FIELDOPTIONS_STRING_PIECE = 2
+  google_protobuf_FieldOptions_STRING = 0,
+  google_protobuf_FieldOptions_CORD = 1,
+  google_protobuf_FieldOptions_STRING_PIECE = 2
 } google_protobuf_FieldOptions_CType;
 
 typedef enum {
-  GOOGLE_PROTOBUF_FIELDOPTIONS_JS_NORMAL = 0,
-  GOOGLE_PROTOBUF_FIELDOPTIONS_JS_STRING = 1,
-  GOOGLE_PROTOBUF_FIELDOPTIONS_JS_NUMBER = 2
+  google_protobuf_FieldOptions_JS_NORMAL = 0,
+  google_protobuf_FieldOptions_JS_STRING = 1,
+  google_protobuf_FieldOptions_JS_NUMBER = 2
 } google_protobuf_FieldOptions_JSType;
 
 typedef enum {
-  GOOGLE_PROTOBUF_FILEOPTIONS_SPEED = 1,
-  GOOGLE_PROTOBUF_FILEOPTIONS_CODE_SIZE = 2,
-  GOOGLE_PROTOBUF_FILEOPTIONS_LITE_RUNTIME = 3
+  google_protobuf_FileOptions_SPEED = 1,
+  google_protobuf_FileOptions_CODE_SIZE = 2,
+  google_protobuf_FileOptions_LITE_RUNTIME = 3
 } google_protobuf_FileOptions_OptimizeMode;
 
-/* Selectors */
-
-/* google.protobuf.DescriptorProto */
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_FIELD_STARTSUBMSG 2
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_NESTED_TYPE_STARTSUBMSG 3
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_ENUM_TYPE_STARTSUBMSG 4
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_EXTENSION_RANGE_STARTSUBMSG 5
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_EXTENSION_STARTSUBMSG 6
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_OPTIONS_STARTSUBMSG 7
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_ONEOF_DECL_STARTSUBMSG 8
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_RESERVED_RANGE_STARTSUBMSG 9
-#define SEL_GOOGLE_PROTOBUF_DESCRIPTORPROTO_FIELD_STARTSEQ 10
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-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.FieldDescriptorProto");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_FieldOptions(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.FieldOptions");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_FileDescriptorProto(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.FileDescriptorProto");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_FileDescriptorSet(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.FileDescriptorSet");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_FileOptions(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.FileOptions");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_MessageOptions(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.MessageOptions");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_MethodDescriptorProto(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.MethodDescriptorProto");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_MethodOptions(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.MethodOptions");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_OneofDescriptorProto(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.OneofDescriptorProto");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_ServiceDescriptorProto(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.ServiceDescriptorProto");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_ServiceOptions(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.ServiceOptions");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.SourceCodeInfo");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_Location(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.SourceCodeInfo.Location");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.UninterpretedOption");
-  assert(m);
-  return m;
-}
-UPB_INLINE const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_NamePart(const upb_symtab *s) {
-  const upb_msgdef *m = upb_symtab_lookupmsg(s, "google.protobuf.UninterpretedOption.NamePart");
-  assert(m);
-  return m;
-}
-
-
-/* EnumDefs */
-UPB_INLINE const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Label(const upb_symtab *s) {
-  const upb_enumdef *e = upb_symtab_lookupenum(s, "google.protobuf.FieldDescriptorProto.Label");
-  assert(e);
-  return e;
-}
-UPB_INLINE const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Type(const upb_symtab *s) {
-  const upb_enumdef *e = upb_symtab_lookupenum(s, "google.protobuf.FieldDescriptorProto.Type");
-  assert(e);
-  return e;
-}
-UPB_INLINE const upb_enumdef *upbdefs_google_protobuf_FieldOptions_CType(const upb_symtab *s) {
-  const upb_enumdef *e = upb_symtab_lookupenum(s, "google.protobuf.FieldOptions.CType");
-  assert(e);
-  return e;
-}
-UPB_INLINE const upb_enumdef *upbdefs_google_protobuf_FieldOptions_JSType(const upb_symtab *s) {
-  const upb_enumdef *e = upb_symtab_lookupenum(s, "google.protobuf.FieldOptions.JSType");
-  assert(e);
-  return e;
-}
-UPB_INLINE const upb_enumdef *upbdefs_google_protobuf_FileOptions_OptimizeMode(const upb_symtab *s) {
-  const upb_enumdef *e = upb_symtab_lookupenum(s, "google.protobuf.FileOptions.OptimizeMode");
-  assert(e);
-  return e;
-}
-
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_end(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto_ExtensionRange(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_start(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto_ExtensionRange(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_end(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto_ReservedRange(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_start(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto_ReservedRange(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_enum_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_extension(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_extension_range(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_field(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_nested_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_oneof_decl(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_reserved_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_reserved_range(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_DescriptorProto(s), 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_allow_alias(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumOptions(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumOptions(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumValueDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_number(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumValueDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumValueDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumValueOptions(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_EnumValueOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_default_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_extendee(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_json_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_label(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_number(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_oneof_index(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_type_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldDescriptorProto(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_ctype(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_jstype(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_lazy(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_packed(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_weak(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FieldOptions(s), 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_dependency(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_enum_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_extension(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_message_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_package(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_public_dependency(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_service(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_source_code_info(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_syntax(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 12); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_weak_dependency(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorProto(s), 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorSet_file(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileDescriptorSet(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_cc_enable_arenas(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 31); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_cc_generic_services(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 16); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_csharp_namespace(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 37); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 23); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_go_package(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 11); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_generate_equals_and_hash(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 20); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_generic_services(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 17); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_multiple_files(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 10); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_outer_classname(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_package(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_java_string_check_utf8(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 27); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_javanano_use_deprecated_package(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 38); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_objc_class_prefix(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 36); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_optimize_for(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 9); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_py_generic_services(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 18); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_FileOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MessageOptions(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_map_entry(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MessageOptions(s), 7); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_message_set_wire_format(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MessageOptions(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_no_standard_descriptor_accessor(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MessageOptions(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MessageOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_client_streaming(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_input_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_output_type(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_server_streaming(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodDescriptorProto(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodOptions(s), 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_MethodOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_OneofDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_OneofDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_method(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_ServiceDescriptorProto(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_ServiceDescriptorProto(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_options(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_ServiceDescriptorProto(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_deprecated(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_ServiceOptions(s), 33); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_uninterpreted_option(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_ServiceOptions(s), 999); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_leading_comments(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo_Location(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_leading_detached_comments(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo_Location(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_path(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo_Location(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_span(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo_Location(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_trailing_comments(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo_Location(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_location(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_SourceCodeInfo(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_is_extension(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption_NamePart(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_name_part(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption_NamePart(s), 1); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_aggregate_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 8); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_double_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 6); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_identifier_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 3); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_name(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 2); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_negative_int_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 5); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_positive_int_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 4); }
-UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_string_value(const upb_symtab *s) { return upb_msgdef_itof(upbdefs_google_protobuf_UninterpretedOption(s), 7); }
+/* MessageDefs: call these functions to get a ref to a msgdef. */
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_EnumDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_EnumOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_EnumValueDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_EnumValueOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_FieldDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_FieldOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_FileDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_FileDescriptorSet_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_FileOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_MessageOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_MethodDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_MethodOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_OneofDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_ServiceDescriptorProto_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_ServiceOptions_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_SourceCodeInfo_Location_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_get(const void *owner);
+const upb_msgdef *upbdefs_google_protobuf_UninterpretedOption_NamePart_get(const void *owner);
+
+/* EnumDefs: call these functions to get a ref to an enumdef. */
+const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Label_get(const void *owner);
+const upb_enumdef *upbdefs_google_protobuf_FieldDescriptorProto_Type_get(const void *owner);
+const upb_enumdef *upbdefs_google_protobuf_FieldOptions_CType_get(const void *owner);
+const upb_enumdef *upbdefs_google_protobuf_FieldOptions_JSType_get(const void *owner);
+const upb_enumdef *upbdefs_google_protobuf_FileOptions_OptimizeMode_get(const void *owner);
+
+/* Functions to test whether this message is of a certain type. */
+UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto.ExtensionRange") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.DescriptorProto.ReservedRange") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_EnumDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_EnumOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_EnumValueDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumValueDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_EnumValueOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.EnumValueOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FieldDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FieldOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FileDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FileDescriptorSet_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileDescriptorSet") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FileOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.FileOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_MessageOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MessageOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_MethodDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MethodDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_MethodOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.MethodOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_OneofDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.OneofDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_ServiceDescriptorProto_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.ServiceDescriptorProto") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_ServiceOptions_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.ServiceOptions") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_SourceCodeInfo_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.SourceCodeInfo") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_SourceCodeInfo_Location_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.SourceCodeInfo.Location") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_UninterpretedOption_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.UninterpretedOption") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_UninterpretedOption_NamePart_is(const upb_msgdef *m) {
+  return strcmp(upb_msgdef_fullname(m), "google.protobuf.UninterpretedOption.NamePart") == 0;
+}
+
+/* Functions to test whether this enum is of a certain type. */
+UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_Label_is(const upb_enumdef *e) {
+  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldDescriptorProto.Label") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FieldDescriptorProto_Type_is(const upb_enumdef *e) {
+  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldDescriptorProto.Type") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_CType_is(const upb_enumdef *e) {
+  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldOptions.CType") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FieldOptions_JSType_is(const upb_enumdef *e) {
+  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FieldOptions.JSType") == 0;
+}
+UPB_INLINE bool upbdefs_google_protobuf_FileOptions_OptimizeMode_is(const upb_enumdef *e) {
+  return strcmp(upb_enumdef_fullname(e), "google.protobuf.FileOptions.OptimizeMode") == 0;
+}
+
+
+/* Functions to get a fielddef from a msgdef reference. */
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_end(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ExtensionRange_f_start(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_end(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_ReservedRange_f_start(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_enum_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_extension_range(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_field(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_nested_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_oneof_decl(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_DescriptorProto_f_reserved_range(const upb_msgdef *m) { assert(upbdefs_google_protobuf_DescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumDescriptorProto_f_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_allow_alias(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_number(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_EnumValueOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_EnumValueOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_default_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_extendee(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_json_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_label(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_number(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_oneof_index(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldDescriptorProto_f_type_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_ctype(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_jstype(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_lazy(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_packed(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FieldOptions_f_weak(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FieldOptions_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_enum_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_message_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_public_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_service(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_source_code_info(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_syntax(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 12); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorProto_f_weak_dependency(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorProto_is(m)); return upb_msgdef_itof(m, 11); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileDescriptorSet_f_file(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileDescriptorSet_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_enable_arenas(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 31); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_cc_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 16); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_csharp_namespace(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 37); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 23); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_go_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 11); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generate_equals_and_hash(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 20); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 17); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_multiple_files(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 10); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_outer_classname(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_java_string_check_utf8(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 27); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_javanano_use_deprecated_package(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 38); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_objc_class_prefix(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 36); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_optimize_for(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 9); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_py_generic_services(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 18); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_FileOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_FileOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_map_entry(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 7); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_message_set_wire_format(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_no_standard_descriptor_accessor(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MessageOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MessageOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_client_streaming(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_input_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_output_type(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodDescriptorProto_f_server_streaming(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 33); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_MethodOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_MethodOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_OneofDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_OneofDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_method(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceDescriptorProto_f_options(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_deprecated(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 33); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_ServiceOptions_f_uninterpreted_option(const upb_msgdef *m) { assert(upbdefs_google_protobuf_ServiceOptions_is(m)); return upb_msgdef_itof(m, 999); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_leading_detached_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_path(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_span(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_Location_f_trailing_comments(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_SourceCodeInfo_f_location(const upb_msgdef *m) { assert(upbdefs_google_protobuf_SourceCodeInfo_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_is_extension(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_NamePart_f_name_part(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m)); return upb_msgdef_itof(m, 1); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_aggregate_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 8); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_double_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 6); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_identifier_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 3); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_name(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 2); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_negative_int_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 5); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_positive_int_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 4); }
+UPB_INLINE const upb_fielddef *upbdefs_google_protobuf_UninterpretedOption_f_string_value(const upb_msgdef *m) { assert(upbdefs_google_protobuf_UninterpretedOption_is(m)); return upb_msgdef_itof(m, 7); }
 
 UPB_END_EXTERN_C
 
@@ -6921,320 +6966,360 @@ UPB_END_EXTERN_C
 namespace upbdefs {
 namespace google {
 namespace protobuf {
-namespace descriptor {
-inline upb::reffed_ptr<const upb::SymbolTable> SymbolTable() {
-  const upb::SymbolTable* s = upbdefs_google_protobuf_descriptor(&s);
-  return upb::reffed_ptr<const upb::SymbolTable>(s, &s);
-}
-}  /* namespace descriptor */
-}  /* namespace protobuf */
-}  /* namespace google */
 
-#define RETURN_REFFED(type, func) \
-    const type* obj = func(upbdefs::google::protobuf::descriptor::SymbolTable().get()); \
-    return upb::reffed_ptr<const type>(obj);
+class DescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  DescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_DescriptorProto_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace DescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_DescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> enum_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_enum_type) }
-inline upb::reffed_ptr<const upb::FieldDef> extension() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_extension) }
-inline upb::reffed_ptr<const upb::FieldDef> extension_range() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_extension_range) }
-inline upb::reffed_ptr<const upb::FieldDef> field() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_field) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> nested_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_nested_type) }
-inline upb::reffed_ptr<const upb::FieldDef> oneof_decl() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_oneof_decl) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_options) }
-inline upb::reffed_ptr<const upb::FieldDef> reserved_name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_reserved_name) }
-inline upb::reffed_ptr<const upb::FieldDef> reserved_range() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_reserved_range) }
-}  /* namespace DescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static DescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_get(&m);
+    return DescriptorProto(m, &m);
+  }
 
-namespace google {
-namespace protobuf {
-namespace DescriptorProto {
-namespace ExtensionRange {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_DescriptorProto_ExtensionRange) }
-inline upb::reffed_ptr<const upb::FieldDef> end() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_ExtensionRange_end) }
-inline upb::reffed_ptr<const upb::FieldDef> start() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_ExtensionRange_start) }
-}  /* namespace ExtensionRange */
-}  /* namespace DescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class ExtensionRange : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+   public:
+    ExtensionRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+        : reffed_ptr(m, ref_donor) {
+      assert(upbdefs_google_protobuf_DescriptorProto_ExtensionRange_is(m));
+    }
 
-namespace google {
-namespace protobuf {
-namespace DescriptorProto {
-namespace ReservedRange {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_DescriptorProto_ReservedRange) }
-inline upb::reffed_ptr<const upb::FieldDef> end() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_ReservedRange_end) }
-inline upb::reffed_ptr<const upb::FieldDef> start() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_DescriptorProto_ReservedRange_start) }
-}  /* namespace ReservedRange */
-}  /* namespace DescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+    static ExtensionRange get() {
+      const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_ExtensionRange_get(&m);
+      return ExtensionRange(m, &m);
+    }
+  };
 
-namespace google {
-namespace protobuf {
-namespace EnumDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_EnumDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumDescriptorProto_options) }
-inline upb::reffed_ptr<const upb::FieldDef> value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumDescriptorProto_value) }
-}  /* namespace EnumDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class ReservedRange : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+   public:
+    ReservedRange(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+        : reffed_ptr(m, ref_donor) {
+      assert(upbdefs_google_protobuf_DescriptorProto_ReservedRange_is(m));
+    }
 
-namespace google {
-namespace protobuf {
-namespace EnumOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_EnumOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> allow_alias() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumOptions_allow_alias) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumOptions_uninterpreted_option) }
-}  /* namespace EnumOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+    static ReservedRange get() {
+      const ::upb::MessageDef* m = upbdefs_google_protobuf_DescriptorProto_ReservedRange_get(&m);
+      return ReservedRange(m, &m);
+    }
+  };
+};
 
-namespace google {
-namespace protobuf {
-namespace EnumValueDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_EnumValueDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumValueDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> number() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumValueDescriptorProto_number) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumValueDescriptorProto_options) }
-}  /* namespace EnumValueDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+class EnumDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  EnumDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_EnumDescriptorProto_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace EnumValueOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_EnumValueOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumValueOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_EnumValueOptions_uninterpreted_option) }
-}  /* namespace EnumValueOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static EnumDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumDescriptorProto_get(&m);
+    return EnumDescriptorProto(m, &m);
+  }
+};
 
-namespace google {
-namespace protobuf {
-namespace FieldDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_FieldDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> default_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_default_value) }
-inline upb::reffed_ptr<const upb::FieldDef> extendee() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_extendee) }
-inline upb::reffed_ptr<const upb::FieldDef> json_name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_json_name) }
-inline upb::reffed_ptr<const upb::FieldDef> label() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_label) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> number() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_number) }
-inline upb::reffed_ptr<const upb::FieldDef> oneof_index() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_oneof_index) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_options) }
-inline upb::reffed_ptr<const upb::FieldDef> type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_type) }
-inline upb::reffed_ptr<const upb::FieldDef> type_name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldDescriptorProto_type_name) }
-inline upb::reffed_ptr<const upb::EnumDef> Label() { RETURN_REFFED(upb::EnumDef, upbdefs_google_protobuf_FieldDescriptorProto_Label) }
-inline upb::reffed_ptr<const upb::EnumDef> Type() { RETURN_REFFED(upb::EnumDef, upbdefs_google_protobuf_FieldDescriptorProto_Type) }
-}  /* namespace FieldDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+class EnumOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  EnumOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_EnumOptions_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace FieldOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_FieldOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> ctype() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_ctype) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> jstype() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_jstype) }
-inline upb::reffed_ptr<const upb::FieldDef> lazy() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_lazy) }
-inline upb::reffed_ptr<const upb::FieldDef> packed() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_packed) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_uninterpreted_option) }
-inline upb::reffed_ptr<const upb::FieldDef> weak() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FieldOptions_weak) }
-inline upb::reffed_ptr<const upb::EnumDef> CType() { RETURN_REFFED(upb::EnumDef, upbdefs_google_protobuf_FieldOptions_CType) }
-inline upb::reffed_ptr<const upb::EnumDef> JSType() { RETURN_REFFED(upb::EnumDef, upbdefs_google_protobuf_FieldOptions_JSType) }
-}  /* namespace FieldOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static EnumOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumOptions_get(&m);
+    return EnumOptions(m, &m);
+  }
+};
 
-namespace google {
-namespace protobuf {
-namespace FileDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_FileDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> dependency() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_dependency) }
-inline upb::reffed_ptr<const upb::FieldDef> enum_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_enum_type) }
-inline upb::reffed_ptr<const upb::FieldDef> extension() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_extension) }
-inline upb::reffed_ptr<const upb::FieldDef> message_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_message_type) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_options) }
-inline upb::reffed_ptr<const upb::FieldDef> package() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_package) }
-inline upb::reffed_ptr<const upb::FieldDef> public_dependency() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_public_dependency) }
-inline upb::reffed_ptr<const upb::FieldDef> service() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_service) }
-inline upb::reffed_ptr<const upb::FieldDef> source_code_info() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_source_code_info) }
-inline upb::reffed_ptr<const upb::FieldDef> syntax() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_syntax) }
-inline upb::reffed_ptr<const upb::FieldDef> weak_dependency() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorProto_weak_dependency) }
-}  /* namespace FileDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+class EnumValueDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  EnumValueDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_EnumValueDescriptorProto_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace FileDescriptorSet {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_FileDescriptorSet) }
-inline upb::reffed_ptr<const upb::FieldDef> file() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileDescriptorSet_file) }
-}  /* namespace FileDescriptorSet */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static EnumValueDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumValueDescriptorProto_get(&m);
+    return EnumValueDescriptorProto(m, &m);
+  }
+};
 
-namespace google {
-namespace protobuf {
-namespace FileOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_FileOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> cc_enable_arenas() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_cc_enable_arenas) }
-inline upb::reffed_ptr<const upb::FieldDef> cc_generic_services() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_cc_generic_services) }
-inline upb::reffed_ptr<const upb::FieldDef> csharp_namespace() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_csharp_namespace) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> go_package() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_go_package) }
-inline upb::reffed_ptr<const upb::FieldDef> java_generate_equals_and_hash() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_generate_equals_and_hash) }
-inline upb::reffed_ptr<const upb::FieldDef> java_generic_services() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_generic_services) }
-inline upb::reffed_ptr<const upb::FieldDef> java_multiple_files() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_multiple_files) }
-inline upb::reffed_ptr<const upb::FieldDef> java_outer_classname() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_outer_classname) }
-inline upb::reffed_ptr<const upb::FieldDef> java_package() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_package) }
-inline upb::reffed_ptr<const upb::FieldDef> java_string_check_utf8() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_java_string_check_utf8) }
-inline upb::reffed_ptr<const upb::FieldDef> javanano_use_deprecated_package() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_javanano_use_deprecated_package) }
-inline upb::reffed_ptr<const upb::FieldDef> objc_class_prefix() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_objc_class_prefix) }
-inline upb::reffed_ptr<const upb::FieldDef> optimize_for() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_optimize_for) }
-inline upb::reffed_ptr<const upb::FieldDef> py_generic_services() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_py_generic_services) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_FileOptions_uninterpreted_option) }
-inline upb::reffed_ptr<const upb::EnumDef> OptimizeMode() { RETURN_REFFED(upb::EnumDef, upbdefs_google_protobuf_FileOptions_OptimizeMode) }
-}  /* namespace FileOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+class EnumValueOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  EnumValueOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_EnumValueOptions_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace MessageOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_MessageOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MessageOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> map_entry() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MessageOptions_map_entry) }
-inline upb::reffed_ptr<const upb::FieldDef> message_set_wire_format() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MessageOptions_message_set_wire_format) }
-inline upb::reffed_ptr<const upb::FieldDef> no_standard_descriptor_accessor() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MessageOptions_no_standard_descriptor_accessor) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MessageOptions_uninterpreted_option) }
-}  /* namespace MessageOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static EnumValueOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_EnumValueOptions_get(&m);
+    return EnumValueOptions(m, &m);
+  }
+};
 
-namespace google {
-namespace protobuf {
-namespace MethodDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_MethodDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> client_streaming() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_client_streaming) }
-inline upb::reffed_ptr<const upb::FieldDef> input_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_input_type) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_options) }
-inline upb::reffed_ptr<const upb::FieldDef> output_type() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_output_type) }
-inline upb::reffed_ptr<const upb::FieldDef> server_streaming() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodDescriptorProto_server_streaming) }
-}  /* namespace MethodDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+class FieldDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  FieldDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_FieldDescriptorProto_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace MethodOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_MethodOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_MethodOptions_uninterpreted_option) }
-}  /* namespace MethodOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static FieldDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_FieldDescriptorProto_get(&m);
+    return FieldDescriptorProto(m, &m);
+  }
 
-namespace google {
-namespace protobuf {
-namespace OneofDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_OneofDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_OneofDescriptorProto_name) }
-}  /* namespace OneofDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class Label : public ::upb::reffed_ptr<const ::upb::EnumDef> {
+   public:
+    Label(const ::upb::EnumDef* e, const void *ref_donor = NULL)
+        : reffed_ptr(e, ref_donor) {
+      assert(upbdefs_google_protobuf_FieldDescriptorProto_Label_is(e));
+    }
+    static Label get() {
+      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Label_get(&e);
+      return Label(e, &e);
+    }
+  };
 
-namespace google {
-namespace protobuf {
-namespace ServiceDescriptorProto {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_ServiceDescriptorProto) }
-inline upb::reffed_ptr<const upb::FieldDef> method() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_ServiceDescriptorProto_method) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_ServiceDescriptorProto_name) }
-inline upb::reffed_ptr<const upb::FieldDef> options() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_ServiceDescriptorProto_options) }
-}  /* namespace ServiceDescriptorProto */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class Type : public ::upb::reffed_ptr<const ::upb::EnumDef> {
+   public:
+    Type(const ::upb::EnumDef* e, const void *ref_donor = NULL)
+        : reffed_ptr(e, ref_donor) {
+      assert(upbdefs_google_protobuf_FieldDescriptorProto_Type_is(e));
+    }
+    static Type get() {
+      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldDescriptorProto_Type_get(&e);
+      return Type(e, &e);
+    }
+  };
+};
 
-namespace google {
-namespace protobuf {
-namespace ServiceOptions {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_ServiceOptions) }
-inline upb::reffed_ptr<const upb::FieldDef> deprecated() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_ServiceOptions_deprecated) }
-inline upb::reffed_ptr<const upb::FieldDef> uninterpreted_option() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_ServiceOptions_uninterpreted_option) }
-}  /* namespace ServiceOptions */
-}  /* namespace protobuf */
-}  /* namespace google */
+class FieldOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  FieldOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_FieldOptions_is(m));
+  }
 
-namespace google {
-namespace protobuf {
-namespace SourceCodeInfo {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_SourceCodeInfo) }
-inline upb::reffed_ptr<const upb::FieldDef> location() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_location) }
-}  /* namespace SourceCodeInfo */
-}  /* namespace protobuf */
-}  /* namespace google */
+  static FieldOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_FieldOptions_get(&m);
+    return FieldOptions(m, &m);
+  }
 
-namespace google {
-namespace protobuf {
-namespace SourceCodeInfo {
-namespace Location {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_SourceCodeInfo_Location) }
-inline upb::reffed_ptr<const upb::FieldDef> leading_comments() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_Location_leading_comments) }
-inline upb::reffed_ptr<const upb::FieldDef> leading_detached_comments() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_Location_leading_detached_comments) }
-inline upb::reffed_ptr<const upb::FieldDef> path() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_Location_path) }
-inline upb::reffed_ptr<const upb::FieldDef> span() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_Location_span) }
-inline upb::reffed_ptr<const upb::FieldDef> trailing_comments() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_SourceCodeInfo_Location_trailing_comments) }
-}  /* namespace Location */
-}  /* namespace SourceCodeInfo */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class CType : public ::upb::reffed_ptr<const ::upb::EnumDef> {
+   public:
+    CType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
+        : reffed_ptr(e, ref_donor) {
+      assert(upbdefs_google_protobuf_FieldOptions_CType_is(e));
+    }
+    static CType get() {
+      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_CType_get(&e);
+      return CType(e, &e);
+    }
+  };
 
-namespace google {
-namespace protobuf {
-namespace UninterpretedOption {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_UninterpretedOption) }
-inline upb::reffed_ptr<const upb::FieldDef> aggregate_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_aggregate_value) }
-inline upb::reffed_ptr<const upb::FieldDef> double_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_double_value) }
-inline upb::reffed_ptr<const upb::FieldDef> identifier_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_identifier_value) }
-inline upb::reffed_ptr<const upb::FieldDef> name() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_name) }
-inline upb::reffed_ptr<const upb::FieldDef> negative_int_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_negative_int_value) }
-inline upb::reffed_ptr<const upb::FieldDef> positive_int_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_positive_int_value) }
-inline upb::reffed_ptr<const upb::FieldDef> string_value() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_string_value) }
-}  /* namespace UninterpretedOption */
-}  /* namespace protobuf */
-}  /* namespace google */
+  class JSType : public ::upb::reffed_ptr<const ::upb::EnumDef> {
+   public:
+    JSType(const ::upb::EnumDef* e, const void *ref_donor = NULL)
+        : reffed_ptr(e, ref_donor) {
+      assert(upbdefs_google_protobuf_FieldOptions_JSType_is(e));
+    }
+    static JSType get() {
+      const ::upb::EnumDef* e = upbdefs_google_protobuf_FieldOptions_JSType_get(&e);
+      return JSType(e, &e);
+    }
+  };
+};
+
+class FileDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  FileDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_FileDescriptorProto_is(m));
+  }
+
+  static FileDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileDescriptorProto_get(&m);
+    return FileDescriptorProto(m, &m);
+  }
+};
+
+class FileDescriptorSet : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  FileDescriptorSet(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_FileDescriptorSet_is(m));
+  }
+
+  static FileDescriptorSet get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileDescriptorSet_get(&m);
+    return FileDescriptorSet(m, &m);
+  }
+};
+
+class FileOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  FileOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_FileOptions_is(m));
+  }
+
+  static FileOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_FileOptions_get(&m);
+    return FileOptions(m, &m);
+  }
+
+  class OptimizeMode : public ::upb::reffed_ptr<const ::upb::EnumDef> {
+   public:
+    OptimizeMode(const ::upb::EnumDef* e, const void *ref_donor = NULL)
+        : reffed_ptr(e, ref_donor) {
+      assert(upbdefs_google_protobuf_FileOptions_OptimizeMode_is(e));
+    }
+    static OptimizeMode get() {
+      const ::upb::EnumDef* e = upbdefs_google_protobuf_FileOptions_OptimizeMode_get(&e);
+      return OptimizeMode(e, &e);
+    }
+  };
+};
+
+class MessageOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  MessageOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_MessageOptions_is(m));
+  }
+
+  static MessageOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_MessageOptions_get(&m);
+    return MessageOptions(m, &m);
+  }
+};
+
+class MethodDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  MethodDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_MethodDescriptorProto_is(m));
+  }
+
+  static MethodDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_MethodDescriptorProto_get(&m);
+    return MethodDescriptorProto(m, &m);
+  }
+};
+
+class MethodOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  MethodOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_MethodOptions_is(m));
+  }
+
+  static MethodOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_MethodOptions_get(&m);
+    return MethodOptions(m, &m);
+  }
+};
+
+class OneofDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  OneofDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_OneofDescriptorProto_is(m));
+  }
+
+  static OneofDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_OneofDescriptorProto_get(&m);
+    return OneofDescriptorProto(m, &m);
+  }
+};
+
+class ServiceDescriptorProto : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  ServiceDescriptorProto(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_ServiceDescriptorProto_is(m));
+  }
+
+  static ServiceDescriptorProto get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_ServiceDescriptorProto_get(&m);
+    return ServiceDescriptorProto(m, &m);
+  }
+};
+
+class ServiceOptions : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  ServiceOptions(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_ServiceOptions_is(m));
+  }
+
+  static ServiceOptions get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_ServiceOptions_get(&m);
+    return ServiceOptions(m, &m);
+  }
+};
+
+class SourceCodeInfo : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  SourceCodeInfo(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_SourceCodeInfo_is(m));
+  }
+
+  static SourceCodeInfo get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_SourceCodeInfo_get(&m);
+    return SourceCodeInfo(m, &m);
+  }
+
+  class Location : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+   public:
+    Location(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+        : reffed_ptr(m, ref_donor) {
+      assert(upbdefs_google_protobuf_SourceCodeInfo_Location_is(m));
+    }
+
+    static Location get() {
+      const ::upb::MessageDef* m = upbdefs_google_protobuf_SourceCodeInfo_Location_get(&m);
+      return Location(m, &m);
+    }
+  };
+};
+
+class UninterpretedOption : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+ public:
+  UninterpretedOption(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+      : reffed_ptr(m, ref_donor) {
+    assert(upbdefs_google_protobuf_UninterpretedOption_is(m));
+  }
+
+  static UninterpretedOption get() {
+    const ::upb::MessageDef* m = upbdefs_google_protobuf_UninterpretedOption_get(&m);
+    return UninterpretedOption(m, &m);
+  }
+
+  class NamePart : public ::upb::reffed_ptr<const ::upb::MessageDef> {
+   public:
+    NamePart(const ::upb::MessageDef* m, const void *ref_donor = NULL)
+        : reffed_ptr(m, ref_donor) {
+      assert(upbdefs_google_protobuf_UninterpretedOption_NamePart_is(m));
+    }
+
+    static NamePart get() {
+      const ::upb::MessageDef* m = upbdefs_google_protobuf_UninterpretedOption_NamePart_get(&m);
+      return NamePart(m, &m);
+    }
+  };
+};
 
-namespace google {
-namespace protobuf {
-namespace UninterpretedOption {
-namespace NamePart {
-inline upb::reffed_ptr<const upb::MessageDef> MessageDef() { RETURN_REFFED(upb::MessageDef, upbdefs_google_protobuf_UninterpretedOption_NamePart) }
-inline upb::reffed_ptr<const upb::FieldDef> is_extension() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_NamePart_is_extension) }
-inline upb::reffed_ptr<const upb::FieldDef> name_part() { RETURN_REFFED(upb::FieldDef, upbdefs_google_protobuf_UninterpretedOption_NamePart_name_part) }
-}  /* namespace NamePart */
-}  /* namespace UninterpretedOption */
 }  /* namespace protobuf */
 }  /* namespace google */
-
 }  /* namespace upbdefs */
 
+#endif  /* __cplusplus */
 
-#undef RETURN_REFFED
-#endif /* __cplusplus */
-
-#endif  /* GOOGLE_PROTOBUF_DESCRIPTOR_UPB_H_ */
+#endif  /* UPB_DESCRIPTOR_DESCRIPTOR_PROTO_UPB_H_ */
 /*
 ** Internal-only definitions for the decoder.
 */
@@ -7242,7 +7327,6 @@ inline upb::reffed_ptr<const upb::FieldDef> name_part() { RETURN_REFFED(upb::Fie
 #ifndef UPB_DECODER_INT_H_
 #define UPB_DECODER_INT_H_
 
-#include <stdlib.h>
 /*
 ** upb::pb::Decoder
 **
@@ -7342,7 +7426,7 @@ class upb::pb::DecoderMethod {
  * constructed.  This hint may be an overestimate for some build configurations.
  * But if the decoder library is upgraded without recompiling the application,
  * it may be an underestimate. */
-#define UPB_PB_DECODER_SIZE 4408
+#define UPB_PB_DECODER_SIZE 4416
 
 #ifdef __cplusplus
 
@@ -8155,49 +8239,44 @@ inline reffed_ptr<const Handlers> Encoder::NewHandlers(
 #include <stdbool.h>
 
 #ifdef __cplusplus
+#include <vector>
+
 extern "C" {
 #endif
 
-/* Loads all defs from the given protobuf binary descriptor, setting default
- * accessors and a default layout on all messages.  The caller owns the
- * returned array of defs, which will be of length *n.  On error NULL is
- * returned and status is set (if non-NULL). */
-upb_def **upb_load_defs_from_descriptor(const char *str, size_t len, int *n,
-                                        void *owner, upb_status *status);
-
-/* Like the previous but also adds the loaded defs to the given symtab. */
-bool upb_load_descriptor_into_symtab(upb_symtab *symtab, const char *str,
-                                     size_t len, upb_status *status);
-
-/* Like the previous but also reads the descriptor from the given filename. */
-bool upb_load_descriptor_file_into_symtab(upb_symtab *symtab, const char *fname,
-                                          upb_status *status);
-
-/* Reads the given filename into a character string, returning NULL if there
- * was an error. */
-char *upb_readfile(const char *filename, size_t *len);
+/* Loads a binary descriptor and returns a NULL-terminated array of unfrozen
+ * filedefs.  The caller owns the returned array, which must be freed with
+ * upb_gfree(). */
+upb_filedef **upb_loaddescriptor(const char *buf, size_t n, const void *owner,
+                                 upb_status *status);
 
 #ifdef __cplusplus
 }  /* extern "C" */
 
 namespace upb {
 
-/* All routines that load descriptors expect the descriptor to be a
- * FileDescriptorSet. */
-inline bool LoadDescriptorFileIntoSymtab(SymbolTable* s, const char *fname,
-                                         Status* status) {
-  return upb_load_descriptor_file_into_symtab(s, fname, status);
-}
+inline bool LoadDescriptor(const char* buf, size_t n, Status* status,
+                           std::vector<reffed_ptr<FileDef> >* files) {
+  FileDef** parsed_files = upb_loaddescriptor(buf, n, &parsed_files, status);
 
-inline bool LoadDescriptorIntoSymtab(SymbolTable* s, const char* str,
-                                     size_t len, Status* status) {
-  return upb_load_descriptor_into_symtab(s, str, len, status);
+  if (parsed_files) {
+    FileDef** p = parsed_files;
+    while (*p) {
+      files->push_back(reffed_ptr<FileDef>(*p, &parsed_files));
+      ++p;
+    }
+    free(parsed_files);
+    return true;
+  } else {
+    return false;
+  }
 }
 
 /* Templated so it can accept both string and std::string. */
 template <typename T>
-bool LoadDescriptorIntoSymtab(SymbolTable* s, const T& desc, Status* status) {
-  return upb_load_descriptor_into_symtab(s, desc.c_str(), desc.size(), status);
+bool LoadDescriptor(const T& desc, Status* status,
+                    std::vector<reffed_ptr<FileDef> >* files) {
+  return LoadDescriptor(desc.c_str(), desc.size(), status, files);
 }
 
 }  /* namespace upb */
@@ -8314,7 +8393,7 @@ UPB_DECLARE_DERIVED_TYPE(upb::json::ParserMethod, upb::RefCounted,
  * constructed.  This hint may be an overestimate for some build configurations.
  * But if the parser library is upgraded without recompiling the application,
  * it may be an underestimate. */
-#define UPB_JSON_PARSER_SIZE 4104
+#define UPB_JSON_PARSER_SIZE 4112
 
 #ifdef __cplusplus
 
@@ -8427,7 +8506,7 @@ UPB_DECLARE_TYPE(upb::json::Printer, upb_json_printer)
 
 /* upb::json::Printer *********************************************************/
 
-#define UPB_JSON_PRINTER_SIZE 168
+#define UPB_JSON_PRINTER_SIZE 176
 
 #ifdef __cplusplus
 
@@ -8440,8 +8519,12 @@ class upb::json::Printer {
   /* The input to the printer. */
   Sink* input();
 
-  /* Returns handlers for printing according to the specified schema. */
-  static reffed_ptr<const Handlers> NewHandlers(const upb::MessageDef* md);
+  /* Returns handlers for printing according to the specified schema.
+   * If preserve_proto_fieldnames is true, the output JSON will use the
+   * original .proto field names (ie. {"my_field":3}) instead of using
+   * camelCased names, which is the default: (eg. {"myField":3}). */
+  static reffed_ptr<const Handlers> NewHandlers(const upb::MessageDef* md,
+                                                bool preserve_proto_fieldnames);
 
   static const size_t kSize = UPB_JSON_PRINTER_SIZE;
 
@@ -8458,6 +8541,7 @@ upb_json_printer *upb_json_printer_create(upb_env *e, const upb_handlers *h,
                                           upb_bytessink *output);
 upb_sink *upb_json_printer_input(upb_json_printer *p);
 const upb_handlers *upb_json_printer_newhandlers(const upb_msgdef *md,
+                                                 bool preserve_fieldnames,
                                                  const void *owner);
 
 UPB_END_EXTERN_C
@@ -8472,8 +8556,9 @@ inline Printer* Printer::Create(Environment* env, const upb::Handlers* handlers,
 }
 inline Sink* Printer::input() { return upb_json_printer_input(this); }
 inline reffed_ptr<const Handlers> Printer::NewHandlers(
-    const upb::MessageDef *md) {
-  const Handlers* h = upb_json_printer_newhandlers(md, &h);
+    const upb::MessageDef *md, bool preserve_proto_fieldnames) {
+  const Handlers* h = upb_json_printer_newhandlers(
+      md, preserve_proto_fieldnames, &h);
   return reffed_ptr<const Handlers>(h, &h);
 }
 }  /* namespace json */
diff --git a/ruby/google-protobuf.gemspec b/ruby/google-protobuf.gemspec
index 7b64ee77..1fa626fe 100644
--- a/ruby/google-protobuf.gemspec
+++ b/ruby/google-protobuf.gemspec
@@ -1,6 +1,6 @@
 Gem::Specification.new do |s|
   s.name        = "google-protobuf"
-  s.version     = "3.0.0.alpha.5.0"
+  s.version     = "3.0.0.alpha.5.0.5"
   s.licenses    = ["BSD"]
   s.summary     = "Protocol Buffers"
   s.description = "Protocol Buffers are Google's data interchange format."
diff --git a/ruby/lib/google/protobuf/repeated_field.rb b/ruby/lib/google/protobuf/repeated_field.rb
index 16c843c0..0ad2060d 100644
--- a/ruby/lib/google/protobuf/repeated_field.rb
+++ b/ruby/lib/google/protobuf/repeated_field.rb
@@ -69,8 +69,8 @@ module Google
       #        relationship explicit instead of implicit
       def_delegators :to_ary,
         :&, :*, :-, :'<=>',
-        :assoc, :bsearch, :combination, :compact, :count, :cycle,
-        :drop, :drop_while, :eql?, :fetch, :find_index, :flatten,
+        :assoc, :bsearch, :bsearch_index, :combination, :compact, :count,
+        :cycle, :dig, :drop, :drop_while, :eql?, :fetch, :find_index, :flatten,
         :include?, :index, :inspect, :join,
         :pack, :permutation, :product, :pretty_print, :pretty_print_cycle,
         :rassoc, :repeated_combination, :repeated_permutation, :reverse,
diff --git a/ruby/tests/basic.rb b/ruby/tests/basic.rb
index 86c74c2a..77c186ef 100644
--- a/ruby/tests/basic.rb
+++ b/ruby/tests/basic.rb
@@ -1161,7 +1161,12 @@ module BasicTest
       return if RUBY_PLATFORM == "java"
       m = MapMessage.new(:map_string_int32 => {"a" => 1})
       expected = '{"mapStringInt32":{"a":1},"mapStringMsg":{}}'
+      expected_preserve = '{"map_string_int32":{"a":1},"map_string_msg":{}}'
       assert MapMessage.encode_json(m) == expected
+
+      json = MapMessage.encode_json(m, :preserve_proto_fieldnames => true)
+      assert json == expected_preserve
+
       m2 = MapMessage.decode_json(MapMessage.encode_json(m))
       assert m == m2
     end
diff --git a/src/Makefile.am b/src/Makefile.am
index 2ba0ef9b..80065506 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -507,6 +507,8 @@ protoc_inputs =                                                   \
   google/protobuf/unittest_preserve_unknown_enum.proto            \
   google/protobuf/unittest.proto                                  \
   google/protobuf/unittest_proto3_arena.proto                     \
+  google/protobuf/unittest_proto3_arena_lite.proto                     \
+  google/protobuf/unittest_proto3_lite.proto                     \
   google/protobuf/unittest_well_known_types.proto                 \
   google/protobuf/util/internal/testdata/anys.proto               \
   google/protobuf/util/internal/testdata/books.proto              \
@@ -609,6 +611,10 @@ protoc_outputs =                                                  \
   google/protobuf/unittest_preserve_unknown_enum.pb.h             \
   google/protobuf/unittest_proto3_arena.pb.cc                     \
   google/protobuf/unittest_proto3_arena.pb.h                      \
+  google/protobuf/unittest_proto3_arena_lite.pb.cc                     \
+  google/protobuf/unittest_proto3_arena_lite.pb.h                      \
+  google/protobuf/unittest_proto3_lite.pb.cc                     \
+  google/protobuf/unittest_proto3_lite.pb.h                      \
   google/protobuf/unittest_well_known_types.pb.cc                 \
   google/protobuf/unittest_well_known_types.pb.h                  \
   google/protobuf/util/internal/testdata/anys.pb.cc               \
@@ -710,6 +716,8 @@ protobuf_test_SOURCES =                                        \
   google/protobuf/no_field_presence_test.cc                    \
   google/protobuf/preserve_unknown_enum_test.cc                \
   google/protobuf/proto3_arena_unittest.cc                     \
+  google/protobuf/proto3_arena_lite_unittest.cc                     \
+  google/protobuf/proto3_lite_unittest.cc                     \
   google/protobuf/reflection_ops_unittest.cc                   \
   google/protobuf/repeated_field_reflection_unittest.cc        \
   google/protobuf/repeated_field_unittest.cc                   \
diff --git a/src/google/protobuf/any.pb.cc b/src/google/protobuf/any.pb.cc
index e8878ba4..fbde4a6d 100644
--- a/src/google/protobuf/any.pb.cc
+++ b/src/google/protobuf/any.pb.cc
@@ -196,13 +196,14 @@ Any* Any::New(::google::protobuf::Arena* arena) const {
 }
 
 void Any::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Any)
   type_url_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   value_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 
 bool Any::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Any)
   for (;;) {
@@ -308,6 +309,7 @@ void Any::SerializeWithCachedSizes(
 }
 
 int Any::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Any)
   int total_size = 0;
 
   // optional string type_url = 1;
@@ -331,18 +333,22 @@ int Any::ByteSize() const {
 }
 
 void Any::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Any)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Any* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Any>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Any)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Any)
     MergeFrom(*source);
   }
 }
 
 void Any::MergeFrom(const Any& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Any)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.type_url().size() > 0) {
 
@@ -355,12 +361,14 @@ void Any::MergeFrom(const Any& from) {
 }
 
 void Any::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Any)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Any::CopyFrom(const Any& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Any)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -423,6 +431,7 @@ void Any::clear_type_url() {
   return type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Any::release_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Any.type_url)
   
   return type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -466,6 +475,7 @@ void Any::clear_value() {
   return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Any::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Any.value)
   
   return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/any.pb.h b/src/google/protobuf/any.pb.h
index 82c70ad9..100a67f6 100644
--- a/src/google/protobuf/any.pb.h
+++ b/src/google/protobuf/any.pb.h
@@ -184,6 +184,7 @@ inline ::std::string* Any::mutable_type_url() {
   return type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Any::release_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Any.type_url)
   
   return type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -227,6 +228,7 @@ inline ::std::string* Any::mutable_value() {
   return value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Any::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Any.value)
   
   return value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/any.proto b/src/google/protobuf/any.proto
index 47d288c3..45db6ede 100644
--- a/src/google/protobuf/any.proto
+++ b/src/google/protobuf/any.proto
@@ -110,6 +110,8 @@ message Any {
   // * If no schema is provided, `https` is assumed.
   // * The last segment of the URL's path must represent the fully
   //   qualified name of the type (as in `path/google.protobuf.Duration`).
+  //   The name should be in a canonical form (e.g., leading "." is
+  //   not accepted).
   // * An HTTP GET on the URL must yield a [google.protobuf.Type][]
   //   value in binary format, or produce an error.
   // * Applications are allowed to cache lookup results based on the
diff --git a/src/google/protobuf/api.pb.cc b/src/google/protobuf/api.pb.cc
index e589a89d..cbeba302 100644
--- a/src/google/protobuf/api.pb.cc
+++ b/src/google/protobuf/api.pb.cc
@@ -265,6 +265,7 @@ Api* Api::New(::google::protobuf::Arena* arena) const {
 }
 
 void Api::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Api)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   version_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   if (GetArenaNoVirtual() == NULL && source_context_ != NULL) delete source_context_;
@@ -277,7 +278,7 @@ void Api::Clear() {
 
 bool Api::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Api)
   for (;;) {
@@ -538,6 +539,7 @@ void Api::SerializeWithCachedSizes(
 }
 
 int Api::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Api)
   int total_size = 0;
 
   // optional string name = 1;
@@ -598,18 +600,22 @@ int Api::ByteSize() const {
 }
 
 void Api::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Api)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Api* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Api>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Api)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Api)
     MergeFrom(*source);
   }
 }
 
 void Api::MergeFrom(const Api& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Api)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   methods_.MergeFrom(from.methods_);
   options_.MergeFrom(from.options_);
@@ -631,12 +637,14 @@ void Api::MergeFrom(const Api& from) {
 }
 
 void Api::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Api)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Api::CopyFrom(const Api& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Api)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -704,6 +712,7 @@ void Api::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Api::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -807,6 +816,7 @@ void Api::clear_version() {
   return version_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Api::release_version() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.version)
   
   return version_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -841,6 +851,7 @@ const ::google::protobuf::SourceContext& Api::source_context() const {
   return source_context_;
 }
 ::google::protobuf::SourceContext* Api::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -984,8 +995,17 @@ Method* Method::New(::google::protobuf::Arena* arena) const {
 }
 
 void Method::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Method)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(Method, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<Method*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -1005,7 +1025,7 @@ void Method::Clear() {
 
 bool Method::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Method)
   for (;;) {
@@ -1269,6 +1289,7 @@ void Method::SerializeWithCachedSizes(
 }
 
 int Method::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Method)
   int total_size = 0;
 
   // optional string name = 1;
@@ -1323,18 +1344,22 @@ int Method::ByteSize() const {
 }
 
 void Method::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Method)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Method* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Method>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Method)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Method)
     MergeFrom(*source);
   }
 }
 
 void Method::MergeFrom(const Method& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Method)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   options_.MergeFrom(from.options_);
   if (from.name().size() > 0) {
@@ -1361,12 +1386,14 @@ void Method::MergeFrom(const Method& from) {
 }
 
 void Method::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Method)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Method::CopyFrom(const Method& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Method)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1434,6 +1461,7 @@ void Method::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Method::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1477,6 +1505,7 @@ void Method::clear_request_type_url() {
   return request_type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Method::release_request_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.request_type_url)
   
   return request_type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1534,6 +1563,7 @@ void Method::clear_response_type_url() {
   return response_type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Method::release_response_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.response_type_url)
   
   return response_type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1678,13 +1708,14 @@ Mixin* Mixin::New(::google::protobuf::Arena* arena) const {
 }
 
 void Mixin::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Mixin)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   root_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 
 bool Mixin::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Mixin)
   for (;;) {
@@ -1802,6 +1833,7 @@ void Mixin::SerializeWithCachedSizes(
 }
 
 int Mixin::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Mixin)
   int total_size = 0;
 
   // optional string name = 1;
@@ -1825,18 +1857,22 @@ int Mixin::ByteSize() const {
 }
 
 void Mixin::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Mixin)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Mixin* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Mixin>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Mixin)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Mixin)
     MergeFrom(*source);
   }
 }
 
 void Mixin::MergeFrom(const Mixin& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Mixin)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.name().size() > 0) {
 
@@ -1849,12 +1885,14 @@ void Mixin::MergeFrom(const Mixin& from) {
 }
 
 void Mixin::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Mixin)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Mixin::CopyFrom(const Mixin& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Mixin)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1917,6 +1955,7 @@ void Mixin::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Mixin::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Mixin.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1960,6 +1999,7 @@ void Mixin::clear_root() {
   return root_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Mixin::release_root() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Mixin.root)
   
   return root_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/api.pb.h b/src/google/protobuf/api.pb.h
index e1dca4e4..bb35e471 100644
--- a/src/google/protobuf/api.pb.h
+++ b/src/google/protobuf/api.pb.h
@@ -468,6 +468,7 @@ inline ::std::string* Api::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Api::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -571,6 +572,7 @@ inline ::std::string* Api::mutable_version() {
   return version_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Api::release_version() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.version)
   
   return version_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -605,6 +607,7 @@ inline ::google::protobuf::SourceContext* Api::mutable_source_context() {
   return source_context_;
 }
 inline ::google::protobuf::SourceContext* Api::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Api.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -699,6 +702,7 @@ inline ::std::string* Method::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Method::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -742,6 +746,7 @@ inline ::std::string* Method::mutable_request_type_url() {
   return request_type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Method::release_request_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.request_type_url)
   
   return request_type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -799,6 +804,7 @@ inline ::std::string* Method::mutable_response_type_url() {
   return response_type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Method::release_response_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Method.response_type_url)
   
   return response_type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -904,6 +910,7 @@ inline ::std::string* Mixin::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Mixin::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Mixin.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -947,6 +954,7 @@ inline ::std::string* Mixin::mutable_root() {
   return root_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Mixin::release_root() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Mixin.root)
   
   return root_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/arena.cc b/src/google/protobuf/arena.cc
index e856f5b1..613e5897 100755
--- a/src/google/protobuf/arena.cc
+++ b/src/google/protobuf/arena.cc
@@ -30,6 +30,7 @@
 
 #include <google/protobuf/arena.h>
 
+
 #ifdef ADDRESS_SANITIZER
 #include <sanitizer/asan_interface.h>
 #endif
@@ -248,6 +249,19 @@ uint64 Arena::SpaceUsed() const {
   return space_used;
 }
 
+pair<uint64, uint64> Arena::SpaceAllocatedAndUsed() const {
+  uint64 allocated = 0;
+  uint64 used = 0;
+
+  Block* b = reinterpret_cast<Block*>(google::protobuf::internal::NoBarrier_Load(&blocks_));
+  while (b != NULL) {
+    allocated += b->size;
+    used += (b->pos - kHeaderSize);
+    b = b->next;
+  }
+  return std::make_pair(allocated, used);
+}
+
 uint64 Arena::FreeBlocks() {
   uint64 space_allocated = 0;
   Block* b = reinterpret_cast<Block*>(google::protobuf::internal::NoBarrier_Load(&blocks_));
diff --git a/src/google/protobuf/arena.h b/src/google/protobuf/arena.h
index 9ab0a0f9..b3d66d91 100644
--- a/src/google/protobuf/arena.h
+++ b/src/google/protobuf/arena.h
@@ -211,7 +211,12 @@ struct ArenaOptions {
 //
 // This protocol is implemented by all arena-enabled proto2 message classes as
 // well as RepeatedPtrField.
+
+#if __cplusplus >= 201103L
+class Arena final {
+#else
 class LIBPROTOBUF_EXPORT Arena {
+#endif
  public:
   // Arena constructor taking custom options. See ArenaOptions below for
   // descriptions of the options available.
@@ -231,7 +236,6 @@ class LIBPROTOBUF_EXPORT Arena {
   // if it was passed in.
   ~Arena();
 
-
   // API to create proto2 message objects on the arena. If the arena passed in
   // is NULL, then a heap allocated object is returned. Type T must be a message
   // defined in a .proto file with cc_enable_arenas set to true, otherwise a
@@ -448,6 +452,10 @@ class LIBPROTOBUF_EXPORT Arena {
   // As above, but does not include any free space in underlying blocks.
   GOOGLE_ATTRIBUTE_NOINLINE uint64 SpaceUsed() const;
 
+  // Combines SpaceAllocated and SpaceUsed. Returns a pair of
+  // <space_allocated, space_used>.
+  GOOGLE_ATTRIBUTE_NOINLINE pair<uint64, uint64> SpaceAllocatedAndUsed() const;
+
   // Frees all storage allocated by this arena after calling destructors
   // registered with OwnDestructor() and freeing objects registered with Own().
   // Any objects allocated on this arena are unusable after this call. It also
diff --git a/src/google/protobuf/arena_unittest.cc b/src/google/protobuf/arena_unittest.cc
index 6b67f446..ab25ffe1 100644
--- a/src/google/protobuf/arena_unittest.cc
+++ b/src/google/protobuf/arena_unittest.cc
@@ -342,6 +342,64 @@ TEST(ArenaTest, Swap) {
   EXPECT_EQ(42, arena2_message->unknown_fields().field(0).varint());
 }
 
+TEST(ArenaTest, ReflectionSwapFields) {
+  Arena arena1;
+  Arena arena2;
+  TestAllTypes* arena1_message;
+  TestAllTypes* arena2_message;
+
+  // Case 1: messages on different arenas, only one message is set.
+  arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  arena2_message = Arena::CreateMessage<TestAllTypes>(&arena2);
+  TestUtil::SetAllFields(arena1_message);
+  const Reflection* reflection = arena1_message->GetReflection();
+  std::vector<const FieldDescriptor*> fields;
+  reflection->ListFields(*arena1_message, &fields);
+  reflection->SwapFields(arena1_message, arena2_message, fields);
+  EXPECT_EQ(&arena1, arena1_message->GetArena());
+  EXPECT_EQ(&arena2, arena2_message->GetArena());
+  string output;
+  arena1_message->SerializeToString(&output);
+  EXPECT_EQ(0, output.size());
+  TestUtil::ExpectAllFieldsSet(*arena2_message);
+  reflection->SwapFields(arena1_message, arena2_message, fields);
+  arena2_message->SerializeToString(&output);
+  EXPECT_EQ(0, output.size());
+  TestUtil::ExpectAllFieldsSet(*arena1_message);
+
+  // Case 2: messages on different arenas, both messages are set.
+  arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  arena2_message = Arena::CreateMessage<TestAllTypes>(&arena2);
+  TestUtil::SetAllFields(arena1_message);
+  TestUtil::SetAllFields(arena2_message);
+  reflection->SwapFields(arena1_message, arena2_message, fields);
+  EXPECT_EQ(&arena1, arena1_message->GetArena());
+  EXPECT_EQ(&arena2, arena2_message->GetArena());
+  TestUtil::ExpectAllFieldsSet(*arena1_message);
+  TestUtil::ExpectAllFieldsSet(*arena2_message);
+
+  // Case 3: messages on different arenas with different lifetimes.
+  arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  {
+    Arena arena3;
+    TestAllTypes* arena3_message = Arena::CreateMessage<TestAllTypes>(&arena3);
+    TestUtil::SetAllFields(arena3_message);
+    reflection->SwapFields(arena1_message, arena3_message, fields);
+  }
+  TestUtil::ExpectAllFieldsSet(*arena1_message);
+
+  // Case 4: one message on arena, the other on heap.
+  arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  TestAllTypes message;
+  TestUtil::SetAllFields(arena1_message);
+  reflection->SwapFields(arena1_message, &message, fields);
+  EXPECT_EQ(&arena1, arena1_message->GetArena());
+  EXPECT_EQ(NULL, message.GetArena());
+  arena1_message->SerializeToString(&output);
+  EXPECT_EQ(0, output.size());
+  TestUtil::ExpectAllFieldsSet(message);
+}
+
 TEST(ArenaTest, SetAllocatedMessage) {
   Arena arena;
   TestAllTypes *arena_message = Arena::CreateMessage<TestAllTypes>(&arena);
diff --git a/src/google/protobuf/arenastring_unittest.cc b/src/google/protobuf/arenastring_unittest.cc
index 3fb582be..ea405d7d 100644
--- a/src/google/protobuf/arenastring_unittest.cc
+++ b/src/google/protobuf/arenastring_unittest.cc
@@ -28,9 +28,6 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// arenastring_unittest.cc is not open-sourced. Do not include in open-source
-// distribution.
-
 // Based on mvels@'s frankenstring.
 
 #include <google/protobuf/arenastring.h>
diff --git a/src/google/protobuf/compiler/command_line_interface.cc b/src/google/protobuf/compiler/command_line_interface.cc
index 87843f62..fcad6b61 100644
--- a/src/google/protobuf/compiler/command_line_interface.cc
+++ b/src/google/protobuf/compiler/command_line_interface.cc
@@ -46,6 +46,7 @@
 #include <unistd.h>
 #endif
 #include <errno.h>
+#include <fstream>
 #include <iostream>
 #include <ctype.h>
 
@@ -948,17 +949,23 @@ bool CommandLineInterface::MakeInputsBeProtoPathRelative(
   return true;
 }
 
+
 CommandLineInterface::ParseArgumentStatus
 CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
   executable_name_ = argv[0];
 
+  vector<string> arguments;
+  for (int i = 1; i < argc; ++i) {
+    arguments.push_back(argv[i]);
+  }
+
   // Iterate through all arguments and parse them.
-  for (int i = 1; i < argc; i++) {
+  for (int i = 0; i < arguments.size(); ++i) {
     string name, value;
 
-    if (ParseArgument(argv[i], &name, &value)) {
+    if (ParseArgument(arguments[i].c_str(), &name, &value)) {
       // Returned true => Use the next argument as the flag value.
-      if (i + 1 == argc || argv[i+1][0] == '-') {
+      if (i + 1 == arguments.size() || arguments[i + 1][0] == '-') {
         std::cerr << "Missing value for flag: " << name << std::endl;
         if (name == "--decode") {
           std::cerr << "To decode an unknown message, use --decode_raw."
@@ -967,7 +974,7 @@ CommandLineInterface::ParseArguments(int argc, const char* const argv[]) {
         return PARSE_ARGUMENT_FAIL;
       } else {
         ++i;
-        value = argv[i];
+        value = arguments[i];
       }
     }
 
diff --git a/src/google/protobuf/compiler/command_line_interface.h b/src/google/protobuf/compiler/command_line_interface.h
index f196ffc5..d1377666 100644
--- a/src/google/protobuf/compiler/command_line_interface.h
+++ b/src/google/protobuf/compiler/command_line_interface.h
@@ -212,6 +212,7 @@ class LIBPROTOC_EXPORT CommandLineInterface {
   // Parse all command-line arguments.
   ParseArgumentStatus ParseArguments(int argc, const char* const argv[]);
 
+
   // Parses a command-line argument into a name/value pair.  Returns
   // true if the next argument in the argv should be used as the value,
   // false otherwise.
diff --git a/src/google/protobuf/compiler/command_line_interface_unittest.cc b/src/google/protobuf/compiler/command_line_interface_unittest.cc
index e3dd2295..ae2900b1 100644
--- a/src/google/protobuf/compiler/command_line_interface_unittest.cc
+++ b/src/google/protobuf/compiler/command_line_interface_unittest.cc
@@ -60,6 +60,7 @@
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
 
@@ -376,7 +377,9 @@ void CommandLineInterfaceTest::CreateTempFile(
 
   // Write file.
   string full_name = temp_directory_ + "/" + name;
-  GOOGLE_CHECK_OK(File::SetContents(full_name, contents, true));
+  GOOGLE_CHECK_OK(File::SetContents(
+      full_name, StringReplace(contents, "$tmpdir", temp_directory_, true),
+      true));
 }
 
 void CommandLineInterfaceTest::CreateTempDir(const string& name) {
@@ -1090,6 +1093,7 @@ TEST_F(CommandLineInterfaceTest, WriteDependencyManifestFileForAbsolutePath) {
 }
 #endif  // !_WIN32
 
+
 // -------------------------------------------------------------------
 
 TEST_F(CommandLineInterfaceTest, ParseErrors) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
index 47729e1c..77451ab1 100644
--- a/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_bootstrap_unittest.cc
@@ -54,6 +54,7 @@
 #include <google/protobuf/stubs/substitute.h>
 
 #include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.cc b/src/google/protobuf/compiler/cpp/cpp_enum.cc
index 415ae60f..c81c5982 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.cc
@@ -98,9 +98,11 @@ void EnumGenerator::GenerateDefinition(io::Printer* printer) {
     vars["number"] = Int32ToString(descriptor_->value(i)->number());
     vars["prefix"] = (descriptor_->containing_type() == NULL) ?
       "" : classname_ + "_";
+    vars["deprecation"] = descriptor_->value(i)->options().deprecated() ?
+        " PROTOBUF_DEPRECATED" : "";
 
     if (i > 0) printer->Print(",\n");
-    printer->Print(vars, "$prefix$$name$ = $number$");
+    printer->Print(vars, "$prefix$$name$$deprecation$ = $number$");
 
     if (descriptor_->value(i)->number() < min_value->number()) {
       min_value = descriptor_->value(i);
@@ -142,15 +144,16 @@ void EnumGenerator::GenerateDefinition(io::Printer* printer) {
       "$prefix$$short_name$_MAX + 1;\n\n");
   }
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(vars,
       "$dllexport$const ::google::protobuf::EnumDescriptor* $classname$_descriptor();\n");
     // The _Name and _Parse methods
-    printer->Print(vars,
-      "inline const ::std::string& $classname$_Name($classname$ value) {\n"
-      "  return ::google::protobuf::internal::NameOfEnum(\n"
-      "    $classname$_descriptor(), value);\n"
-      "}\n");
+    printer->Print(
+        vars,
+        "inline const ::std::string& $classname$_Name($classname$ value) {\n"
+        "  return ::google::protobuf::internal::NameOfEnum(\n"
+        "    $classname$_descriptor(), value);\n"
+        "}\n");
     printer->Print(vars,
       "inline bool $classname$_Parse(\n"
       "    const ::std::string& name, $classname$* value) {\n"
@@ -166,7 +169,7 @@ GenerateGetEnumDescriptorSpecializations(io::Printer* printer) {
       "template <> struct is_proto_enum< $classname$> : ::google::protobuf::internal::true_type "
       "{};\n",
       "classname", ClassName(descriptor_, true));
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(
       "template <>\n"
       "inline const EnumDescriptor* GetEnumDescriptor< $classname$>() {\n"
@@ -185,8 +188,11 @@ void EnumGenerator::GenerateSymbolImports(io::Printer* printer) {
 
   for (int j = 0; j < descriptor_->value_count(); j++) {
     vars["tag"] = EnumValueName(descriptor_->value(j));
+    vars["deprecated_attr"] = descriptor_->value(j)->options().deprecated() ?
+      "PROTOBUF_DEPRECATED_ATTR " : "";
     printer->Print(vars,
-      "static $constexpr$const $nested_name$ $tag$ = $classname$_$tag$;\n");
+      "$deprecated_attr$static $constexpr$const $nested_name$ $tag$ =\n"
+      "  $classname$_$tag$;\n");
   }
 
   printer->Print(vars,
@@ -203,16 +209,18 @@ void EnumGenerator::GenerateSymbolImports(io::Printer* printer) {
       "  $classname$_$nested_name$_ARRAYSIZE;\n");
   }
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(vars,
       "static inline const ::google::protobuf::EnumDescriptor*\n"
       "$nested_name$_descriptor() {\n"
       "  return $classname$_descriptor();\n"
       "}\n");
     printer->Print(vars,
-      "static inline const ::std::string& $nested_name$_Name($nested_name$ value) {\n"
-      "  return $classname$_Name(value);\n"
-      "}\n");
+                   "static inline const ::std::string& "
+                   "$nested_name$_Name($nested_name$ value) {"
+                   "\n"
+                   "  return $classname$_Name(value);\n"
+                   "}\n");
     printer->Print(vars,
       "static inline bool $nested_name$_Parse(const ::std::string& name,\n"
       "    $nested_name$* value) {\n"
@@ -242,7 +250,7 @@ void EnumGenerator::GenerateMethods(io::Printer* printer) {
   vars["classname"] = classname_;
   vars["constexpr"] = options_.proto_h ? "constexpr " : "";
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(vars,
       "const ::google::protobuf::EnumDescriptor* $classname$_descriptor() {\n"
       "  protobuf_AssignDescriptorsOnce();\n"
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum.h b/src/google/protobuf/compiler/cpp/cpp_enum.h
index 61e40346..90edf001 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum.h
+++ b/src/google/protobuf/compiler/cpp/cpp_enum.h
@@ -35,12 +35,12 @@
 #ifndef GOOGLE_PROTOBUF_COMPILER_CPP_ENUM_H__
 #define GOOGLE_PROTOBUF_COMPILER_CPP_ENUM_H__
 
+#include <map>
 #include <set>
 #include <string>
 #include <google/protobuf/compiler/cpp/cpp_options.h>
 #include <google/protobuf/descriptor.h>
 
-
 namespace google {
 namespace protobuf {
   namespace io {
@@ -55,8 +55,7 @@ namespace cpp {
 class EnumGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
-  explicit EnumGenerator(const EnumDescriptor* descriptor,
-                         const Options& options);
+  EnumGenerator(const EnumDescriptor* descriptor, const Options& options);
   ~EnumGenerator();
 
   // Header stuff.
@@ -96,10 +95,10 @@ class EnumGenerator {
 
  private:
   const EnumDescriptor* descriptor_;
-  string classname_;
-  Options options_;
+  const string classname_;
+  const Options& options_;
   // whether to generate the *_ARRAYSIZE constant.
-  bool generate_array_size_;
+  const bool generate_array_size_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(EnumGenerator);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
index 06cb18d1..10252b39 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.cc
@@ -59,10 +59,9 @@ void SetEnumVariables(const FieldDescriptor* descriptor,
 
 // ===================================================================
 
-EnumFieldGenerator::
-EnumFieldGenerator(const FieldDescriptor* descriptor,
-                   const Options& options)
-  : descriptor_(descriptor) {
+EnumFieldGenerator::EnumFieldGenerator(const FieldDescriptor* descriptor,
+                                       const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetEnumVariables(descriptor, &variables_, options);
 }
 
@@ -76,8 +75,8 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void EnumFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$ $name$() const$deprecation$;\n"
-    "void set_$name$($type$ value)$deprecation$;\n");
+    "$deprecated_attr$$type$ $name$() const;\n"
+    "$deprecated_attr$void set_$name$($type$ value);\n");
 }
 
 void EnumFieldGenerator::
@@ -136,7 +135,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
     printer->Print(variables_,
       "if ($type$_IsValid(value)) {\n"
       "  set_$name$(static_cast< $type$ >(value));\n");
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(variables_,
         "} else {\n"
         "  mutable_unknown_fields()->AddVarint($number$, value);\n");
@@ -230,10 +229,9 @@ GenerateConstructorCode(io::Printer* printer) const {
 
 // ===================================================================
 
-RepeatedEnumFieldGenerator::
-RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
-                           const Options& options)
-  : descriptor_(descriptor) {
+RepeatedEnumFieldGenerator::RepeatedEnumFieldGenerator(
+    const FieldDescriptor* descriptor, const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetEnumVariables(descriptor, &variables_, options);
 }
 
@@ -243,8 +241,8 @@ void RepeatedEnumFieldGenerator::
 GeneratePrivateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "::google::protobuf::RepeatedField<int> $name$_;\n");
-  if (descriptor_->is_packed()
-      && HasGeneratedMethods(descriptor_->file())) {
+  if (descriptor_->is_packed() &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
     printer->Print(variables_,
       "mutable int _$name$_cached_byte_size_;\n");
   }
@@ -253,12 +251,12 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedEnumFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$ $name$(int index) const$deprecation$;\n"
-    "void set_$name$(int index, $type$ value)$deprecation$;\n"
-    "void add_$name$($type$ value)$deprecation$;\n");
+    "$deprecated_attr$$type$ $name$(int index) const;\n"
+    "$deprecated_attr$void set_$name$(int index, $type$ value);\n"
+    "$deprecated_attr$void add_$name$($type$ value);\n");
   printer->Print(variables_,
-    "const ::google::protobuf::RepeatedField<int>& $name$() const$deprecation$;\n"
-    "::google::protobuf::RepeatedField<int>* mutable_$name$()$deprecation$;\n");
+    "$deprecated_attr$const ::google::protobuf::RepeatedField<int>& $name$() const;\n"
+    "$deprecated_attr$::google::protobuf::RepeatedField<int>* mutable_$name$();\n");
 }
 
 void RepeatedEnumFieldGenerator::
@@ -337,7 +335,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
     printer->Print(variables_,
       "if ($type$_IsValid(value)) {\n"
       "  add_$name$(static_cast< $type$ >(value));\n");
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(variables_,
         "} else {\n"
         "  mutable_unknown_fields()->AddVarint($number$, value);\n");
@@ -364,7 +362,7 @@ GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
         "       NULL,\n"
         "       NULL,\n"
         "       this->mutable_$name$())));\n");
-    } else if (UseUnknownFieldSet(descriptor_->file())) {
+    } else if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(variables_,
         "DO_((::google::protobuf::internal::WireFormat::ReadPackedEnumPreserveUnknowns(\n"
         "       input,\n"
@@ -401,7 +399,7 @@ GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
       "  if ($type$_IsValid(value)) {\n"
       "    add_$name$(static_cast< $type$ >(value));\n"
       "  } else {\n");
-      if (UseUnknownFieldSet(descriptor_->file())) {
+      if (UseUnknownFieldSet(descriptor_->file(), options_)) {
         printer->Print(variables_,
         "    mutable_unknown_fields()->AddVarint($number$, value);\n");
       } else {
diff --git a/src/google/protobuf/compiler/cpp/cpp_enum_field.h b/src/google/protobuf/compiler/cpp/cpp_enum_field.h
index 5b1d01ea..fe21c575 100644
--- a/src/google/protobuf/compiler/cpp/cpp_enum_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_enum_field.h
@@ -46,8 +46,7 @@ namespace cpp {
 
 class EnumFieldGenerator : public FieldGenerator {
  public:
-  explicit EnumFieldGenerator(const FieldDescriptor* descriptor,
-                              const Options& options);
+  EnumFieldGenerator(const FieldDescriptor* descriptor, const Options& options);
   ~EnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -74,8 +73,8 @@ class EnumFieldGenerator : public FieldGenerator {
 
 class EnumOneofFieldGenerator : public EnumFieldGenerator {
  public:
-  explicit EnumOneofFieldGenerator(const FieldDescriptor* descriptor,
-                                   const Options& options);
+  EnumOneofFieldGenerator(const FieldDescriptor* descriptor,
+                          const Options& options);
   ~EnumOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -91,8 +90,8 @@ class EnumOneofFieldGenerator : public EnumFieldGenerator {
 
 class RepeatedEnumFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
-                                      const Options& options);
+  RepeatedEnumFieldGenerator(const FieldDescriptor* descriptor,
+                             const Options& options);
   ~RepeatedEnumFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.cc b/src/google/protobuf/compiler/cpp/cpp_field.cc
index 8d47d4e0..b3ba3a2e 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_field.cc
@@ -77,6 +77,8 @@ void SetCommonFieldVariables(const FieldDescriptor* descriptor,
     WireFormat::TagSize(descriptor->number(), descriptor->type()));
   (*variables)["deprecation"] = descriptor->options().deprecated()
       ? " PROTOBUF_DEPRECATED" : "";
+  (*variables)["deprecated_attr"] = descriptor->options().deprecated()
+      ? "PROTOBUF_DEPRECATED_ATTR " : "";
 
   (*variables)["cppget"] = "Get";
 
@@ -121,6 +123,7 @@ GenerateMergeFromCodedStreamWithPacking(io::Printer* printer) const {
 FieldGeneratorMap::FieldGeneratorMap(const Descriptor* descriptor,
                                      const Options& options)
     : descriptor_(descriptor),
+      options_(options),
       field_generators_(
           new google::protobuf::scoped_ptr<FieldGenerator>[descriptor->field_count()]) {
   // Construct all the FieldGenerators.
diff --git a/src/google/protobuf/compiler/cpp/cpp_field.h b/src/google/protobuf/compiler/cpp/cpp_field.h
index 1d7f8233..3b012527 100644
--- a/src/google/protobuf/compiler/cpp/cpp_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_field.h
@@ -69,7 +69,7 @@ void SetCommonOneofFieldVariables(const FieldDescriptor* descriptor,
 
 class FieldGenerator {
  public:
-  FieldGenerator() {}
+  explicit FieldGenerator(const Options& options) : options_(options) {}
   virtual ~FieldGenerator();
 
   // Generate lines of code declaring members fields of the message class
@@ -194,6 +194,9 @@ class FieldGenerator {
   // are placed in the message's ByteSize() method.
   virtual void GenerateByteSize(io::Printer* printer) const = 0;
 
+ protected:
+  const Options& options_;
+
  private:
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldGenerator);
 };
@@ -201,13 +204,14 @@ class FieldGenerator {
 // Convenience class which constructs FieldGenerators for a Descriptor.
 class FieldGeneratorMap {
  public:
-  explicit FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
+  FieldGeneratorMap(const Descriptor* descriptor, const Options& options);
   ~FieldGeneratorMap();
 
   const FieldGenerator& get(const FieldDescriptor* field) const;
 
  private:
   const Descriptor* descriptor_;
+  const Options& options_;
   google::protobuf::scoped_array<google::protobuf::scoped_ptr<FieldGenerator> > field_generators_;
 
   static FieldGenerator* MakeGenerator(const FieldDescriptor* field,
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.cc b/src/google/protobuf/compiler/cpp/cpp_file.cc
index d48171b0..385b973e 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_file.cc
@@ -59,6 +59,7 @@ namespace cpp {
 
 FileGenerator::FileGenerator(const FileDescriptor* file, const Options& options)
     : file_(file),
+      options_(options),
       message_generators_(
           new google::protobuf::scoped_ptr<MessageGenerator>[file->message_type_count()]),
       enum_generators_(
@@ -66,8 +67,7 @@ FileGenerator::FileGenerator(const FileDescriptor* file, const Options& options)
       service_generators_(
           new google::protobuf::scoped_ptr<ServiceGenerator>[file->service_count()]),
       extension_generators_(
-          new google::protobuf::scoped_ptr<ExtensionGenerator>[file->extension_count()]),
-      options_(options) {
+          new google::protobuf::scoped_ptr<ExtensionGenerator>[file->extension_count()]) {
 
   for (int i = 0; i < file->message_type_count(); i++) {
     message_generators_[i].reset(
@@ -267,12 +267,12 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
     "right", use_system_include ? ">" : "\"");
 
   // Unknown fields implementation in lite mode uses StringOutputStream
-  if (!UseUnknownFieldSet(file_) && file_->message_type_count() > 0) {
+  if (!UseUnknownFieldSet(file_, options_) && file_->message_type_count() > 0) {
     printer->Print(
       "#include <google/protobuf/io/zero_copy_stream_impl_lite.h>\n");
   }
 
-  if (HasDescriptorMethods(file_)) {
+  if (HasDescriptorMethods(file_, options_)) {
     printer->Print(
       "#include <google/protobuf/descriptor.h>\n"
       "#include <google/protobuf/generated_message_reflection.h>\n"
@@ -297,7 +297,7 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
 
   GenerateNamespaceOpeners(printer);
 
-  if (HasDescriptorMethods(file_)) {
+  if (HasDescriptorMethods(file_, options_)) {
     printer->Print(
       "\n"
       "namespace {\n"
@@ -311,7 +311,7 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
         "name", ClassName(file_->enum_type(i), false));
     }
 
-    if (HasGenericServices(file_)) {
+    if (HasGenericServices(file_, options_)) {
       for (int i = 0; i < file_->service_count(); i++) {
         printer->Print(
           "const ::google::protobuf::ServiceDescriptor* $name$_descriptor_ = NULL;\n",
@@ -336,7 +336,7 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
 
   // Generate classes.
   for (int i = 0; i < file_->message_type_count(); i++) {
-    if (i == 0 && HasGeneratedMethods(file_)) {
+    if (i == 0 && HasGeneratedMethods(file_, options_)) {
       printer->Print(
           "\n"
           "namespace {\n"
@@ -361,7 +361,7 @@ void FileGenerator::GenerateSource(io::Printer* printer) {
     printer->Print("#endif  // PROTOBUF_INLINE_NOT_IN_HEADERS\n");
   }
 
-  if (HasGenericServices(file_)) {
+  if (HasGenericServices(file_, options_)) {
     // Generate services.
     for (int i = 0; i < file_->service_count(); i++) {
       if (i == 0) printer->Print("\n");
@@ -462,7 +462,7 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
 
   // In optimize_for = LITE_RUNTIME mode, we don't generate AssignDescriptors()
   // and we only use AddDescriptors() to allocate default instances.
-  if (HasDescriptorMethods(file_)) {
+  if (HasDescriptorMethods(file_, options_)) {
     printer->Print(
       "\n"
       "void $assigndescriptorsname$() {\n",
@@ -495,7 +495,7 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     for (int i = 0; i < file_->enum_type_count(); i++) {
       enum_generators_[i]->GenerateDescriptorInitializer(printer, i);
     }
-    if (HasGenericServices(file_)) {
+    if (HasGenericServices(file_, options_)) {
       for (int i = 0; i < file_->service_count(); i++) {
         service_generators_[i]->GenerateDescriptorInitializer(printer, i);
       }
@@ -561,22 +561,23 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
 
   // Now generate the AddDescriptors() function.
   PrintHandlingOptionalStaticInitializers(
-    file_, printer,
-    // With static initializers.
-    // Note that we don't need any special synchronization in the following code
-    // because it is called at static init time before any threads exist.
-    "void $adddescriptorsname$() {\n"
-    "  static bool already_here = false;\n"
-    "  if (already_here) return;\n"
-    "  already_here = true;\n"
-    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
-    "\n",
-    // Without.
-    "void $adddescriptorsname$_impl() {\n"
-    "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
-    "\n",
-    // Vars.
-    "adddescriptorsname", GlobalAddDescriptorsName(file_->name()));
+      file_, options_, printer,
+      // With static initializers.
+      // Note that we don't need any special synchronization in the following
+      // code
+      // because it is called at static init time before any threads exist.
+      "void $adddescriptorsname$() {\n"
+      "  static bool already_here = false;\n"
+      "  if (already_here) return;\n"
+      "  already_here = true;\n"
+      "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
+      "\n",
+      // Without.
+      "void $adddescriptorsname$_impl() {\n"
+      "  GOOGLE_PROTOBUF_VERIFY_VERSION;\n"
+      "\n",
+      // Vars.
+      "adddescriptorsname", GlobalAddDescriptorsName(file_->name()));
 
   printer->Indent();
 
@@ -593,7 +594,7 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
       "name", add_desc_name);
   }
 
-  if (HasDescriptorMethods(file_)) {
+  if (HasDescriptorMethods(file_, options_)) {
     // Embed the descriptor.  We simply serialize the entire FileDescriptorProto
     // and embed it as a string literal, which is parsed and built into real
     // descriptors at initialization time.
@@ -687,23 +688,23 @@ void FileGenerator::GenerateBuildDescriptors(io::Printer* printer) {
     "\n");
 
   PrintHandlingOptionalStaticInitializers(
-    file_, printer,
-    // With static initializers.
-    "// Force AddDescriptors() to be called at static initialization time.\n"
-    "struct StaticDescriptorInitializer_$filename$ {\n"
-    "  StaticDescriptorInitializer_$filename$() {\n"
-    "    $adddescriptorsname$();\n"
-    "  }\n"
-    "} static_descriptor_initializer_$filename$_;\n",
-    // Without.
-    "GOOGLE_PROTOBUF_DECLARE_ONCE($adddescriptorsname$_once_);\n"
-    "void $adddescriptorsname$() {\n"
-    "  ::google::protobuf::GoogleOnceInit(&$adddescriptorsname$_once_,\n"
-    "                 &$adddescriptorsname$_impl);\n"
-    "}\n",
-    // Vars.
-    "adddescriptorsname", GlobalAddDescriptorsName(file_->name()),
-    "filename", FilenameIdentifier(file_->name()));
+      file_, options_, printer,
+      // With static initializers.
+      "// Force AddDescriptors() to be called at static initialization time.\n"
+      "struct StaticDescriptorInitializer_$filename$ {\n"
+      "  StaticDescriptorInitializer_$filename$() {\n"
+      "    $adddescriptorsname$();\n"
+      "  }\n"
+      "} static_descriptor_initializer_$filename$_;\n",
+      // Without.
+      "GOOGLE_PROTOBUF_DECLARE_ONCE($adddescriptorsname$_once_);\n"
+      "void $adddescriptorsname$() {\n"
+      "  ::google::protobuf::GoogleOnceInit(&$adddescriptorsname$_once_,\n"
+      "                 &$adddescriptorsname$_impl);\n"
+      "}\n",
+      // Vars.
+      "adddescriptorsname", GlobalAddDescriptorsName(file_->name()), "filename",
+      FilenameIdentifier(file_->name()));
 }
 
 void FileGenerator::GenerateNamespaceOpeners(io::Printer* printer) {
@@ -760,16 +761,15 @@ void FileGenerator::GenerateTopHeaderGuard(io::Printer* printer,
                                            const string& filename_identifier) {
   // Generate top of header.
   printer->Print(
-    "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
-    "// source: $filename$\n"
-    "\n"
-    "#ifndef PROTOBUF_$filename_identifier$__INCLUDED\n"
-    "#define PROTOBUF_$filename_identifier$__INCLUDED\n"
-    "\n"
-    "#include <string>\n"
-    "\n",
-    "filename", file_->name(),
-    "filename_identifier", filename_identifier);
+      "// Generated by the protocol buffer compiler.  DO NOT EDIT!\n"
+      "// source: $filename$\n"
+      "\n"
+      "#ifndef PROTOBUF_$filename_identifier$__INCLUDED\n"
+      "#define PROTOBUF_$filename_identifier$__INCLUDED\n"
+      "\n"
+      "#include <string>\n",
+      "filename", file_->name(), "filename_identifier", filename_identifier);
+  printer->Print("\n");
 }
 
 void FileGenerator::GenerateBottomHeaderGuard(
@@ -808,12 +808,12 @@ void FileGenerator::GenerateLibraryIncludes(io::Printer* printer) {
     "#include <google/protobuf/arena.h>\n"
     "#include <google/protobuf/arenastring.h>\n"
     "#include <google/protobuf/generated_message_util.h>\n");
-  if (UseUnknownFieldSet(file_)) {
+  if (UseUnknownFieldSet(file_, options_)) {
     printer->Print(
       "#include <google/protobuf/metadata.h>\n");
   }
   if (file_->message_type_count() > 0) {
-    if (HasDescriptorMethods(file_)) {
+    if (HasDescriptorMethods(file_, options_)) {
       printer->Print(
         "#include <google/protobuf/message.h>\n");
     } else {
@@ -827,7 +827,7 @@ void FileGenerator::GenerateLibraryIncludes(io::Printer* printer) {
   if (HasMapFields(file_)) {
     printer->Print(
         "#include <google/protobuf/map.h>\n");
-    if (HasDescriptorMethods(file_)) {
+    if (HasDescriptorMethods(file_, options_)) {
       printer->Print(
           "#include <google/protobuf/map_field_inl.h>\n");
     } else {
@@ -837,7 +837,7 @@ void FileGenerator::GenerateLibraryIncludes(io::Printer* printer) {
   }
 
   if (HasEnumDefinitions(file_)) {
-    if (HasDescriptorMethods(file_)) {
+    if (HasDescriptorMethods(file_, options_)) {
       printer->Print(
           "#include <google/protobuf/generated_enum_reflection.h>\n");
     } else {
@@ -846,12 +846,12 @@ void FileGenerator::GenerateLibraryIncludes(io::Printer* printer) {
     }
   }
 
-  if (HasGenericServices(file_)) {
+  if (HasGenericServices(file_, options_)) {
     printer->Print(
       "#include <google/protobuf/service.h>\n");
   }
 
-  if (UseUnknownFieldSet(file_) && file_->message_type_count() > 0) {
+  if (UseUnknownFieldSet(file_, options_) && file_->message_type_count() > 0) {
     printer->Print(
       "#include <google/protobuf/unknown_field_set.h>\n");
   }
@@ -955,7 +955,7 @@ void FileGenerator::GenerateEnumDefinitions(io::Printer* printer) {
 }
 
 void FileGenerator::GenerateServiceDefinitions(io::Printer* printer) {
-  if (HasGenericServices(file_)) {
+  if (HasGenericServices(file_, options_)) {
     // Generate service definitions.
     for (int i = 0; i < file_->service_count(); i++) {
       if (i > 0) {
diff --git a/src/google/protobuf/compiler/cpp/cpp_file.h b/src/google/protobuf/compiler/cpp/cpp_file.h
index ebe990c2..5dcf692b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_file.h
+++ b/src/google/protobuf/compiler/cpp/cpp_file.h
@@ -65,8 +65,7 @@ class ExtensionGenerator;      // extension.h
 class FileGenerator {
  public:
   // See generator.cc for the meaning of dllexport_decl.
-  explicit FileGenerator(const FileDescriptor* file,
-                         const Options& options);
+  FileGenerator(const FileDescriptor* file, const Options& options);
   ~FileGenerator();
 
   // info_path, if non-empty, should be the path (relative to printer's output)
@@ -144,6 +143,7 @@ class FileGenerator {
   void GenerateProto2NamespaceEnumSpecializations(io::Printer* printer);
 
   const FileDescriptor* file_;
+  const Options options_;
 
   google::protobuf::scoped_array<google::protobuf::scoped_ptr<MessageGenerator> > message_generators_;
   google::protobuf::scoped_array<google::protobuf::scoped_ptr<EnumGenerator> > enum_generators_;
@@ -152,7 +152,6 @@ class FileGenerator {
 
   // E.g. if the package is foo.bar, package_parts_ is {"foo", "bar"}.
   vector<string> package_parts_;
-  const Options options_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FileGenerator);
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_generator.cc b/src/google/protobuf/compiler/cpp/cpp_generator.cc
index c7aec93a..31d189c2 100644
--- a/src/google/protobuf/compiler/cpp/cpp_generator.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_generator.cc
@@ -96,6 +96,8 @@ bool CppGenerator::Generate(const FileDescriptor* file,
       file_options.annotation_pragma_name = options[i].second;
     } else if (options[i].first == "annotation_guard_name") {
       file_options.annotation_guard_name = options[i].second;
+    } else if (options[i].first == "lite") {
+      file_options.enforce_lite = true;
     } else {
       *error = "Unknown generator option: " + options[i].first;
       return false;
@@ -123,7 +125,7 @@ bool CppGenerator::Generate(const FileDescriptor* file,
     file_generator.GenerateProtoHeader(
         &printer, file_options.annotate_headers ? info_path : "");
     if (file_options.annotate_headers) {
-      scoped_ptr<io::ZeroCopyOutputStream> info_output(
+      google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> info_output(
           generator_context->Open(info_path));
       annotations.SerializeToZeroCopyStream(info_output.get());
     }
@@ -143,7 +145,7 @@ bool CppGenerator::Generate(const FileDescriptor* file,
     file_generator.GeneratePBHeader(
         &printer, file_options.annotate_headers ? info_path : "");
     if (file_options.annotate_headers) {
-      scoped_ptr<io::ZeroCopyOutputStream> info_output(
+      google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> info_output(
           generator_context->Open(info_path));
       annotations.SerializeToZeroCopyStream(info_output.get());
     }
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.cc b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
index fb46e387..2ad4d36a 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.cc
@@ -68,14 +68,15 @@ const char* const kKeywordList[] = {
   "alignas", "alignof", "and", "and_eq", "asm", "auto", "bitand", "bitor",
   "bool", "break", "case", "catch", "char", "class", "compl", "const",
   "constexpr", "const_cast", "continue", "decltype", "default", "delete", "do",
-  "double", "dynamic_cast", "else", "enum", "explicit", "extern", "false",
-  "float", "for", "friend", "goto", "if", "inline", "int", "long", "mutable",
-  "namespace", "new", "noexcept", "not", "not_eq", "NULL", "operator", "or",
-  "or_eq", "private", "protected", "public", "register", "reinterpret_cast",
-  "return", "short", "signed", "sizeof", "static", "static_assert",
-  "static_cast", "struct", "switch", "template", "this", "thread_local",
-  "throw", "true", "try", "typedef", "typeid", "typename", "union", "unsigned",
-  "using", "virtual", "void", "volatile", "wchar_t", "while", "xor", "xor_eq"
+  "double", "dynamic_cast", "else", "enum", "explicit", "export", "extern",
+  "false", "float", "for", "friend", "goto", "if", "inline", "int", "long",
+  "mutable", "namespace", "new", "noexcept", "not", "not_eq", "NULL",
+  "operator", "or", "or_eq", "private", "protected", "public", "register",
+  "reinterpret_cast", "return", "short", "signed", "sizeof", "static",
+  "static_assert", "static_cast", "struct", "switch", "template", "this",
+  "thread_local", "throw", "true", "try", "typedef", "typeid", "typename",
+  "union", "unsigned", "using", "virtual", "void", "volatile", "wchar_t",
+  "while", "xor", "xor_eq"
 };
 
 hash_set<string> MakeKeywordsMap() {
@@ -171,9 +172,10 @@ string DependentBaseClassTemplateName(const Descriptor* descriptor) {
   return ClassName(descriptor, false) + "_InternalBase";
 }
 
-string SuperClassName(const Descriptor* descriptor) {
-  return HasDescriptorMethods(descriptor->file()) ?
-      "::google::protobuf::Message" : "::google::protobuf::MessageLite";
+string SuperClassName(const Descriptor* descriptor, const Options& options) {
+  return HasDescriptorMethods(descriptor->file(), options)
+             ? "::google::protobuf::Message"
+             : "::google::protobuf::MessageLite";
 }
 
 string DependentBaseDownCast() {
@@ -485,8 +487,9 @@ string SafeFunctionName(const Descriptor* descriptor,
   return function_name;
 }
 
-bool StaticInitializersForced(const FileDescriptor* file) {
-  if (HasDescriptorMethods(file) || file->extension_count() > 0) {
+bool StaticInitializersForced(const FileDescriptor* file,
+                              const Options& options) {
+  if (HasDescriptorMethods(file, options) || file->extension_count() > 0) {
     return true;
   }
   for (int i = 0; i < file->message_type_count(); ++i) {
@@ -498,10 +501,10 @@ bool StaticInitializersForced(const FileDescriptor* file) {
 }
 
 void PrintHandlingOptionalStaticInitializers(
-    const FileDescriptor* file, io::Printer* printer,
+    const FileDescriptor* file, const Options& options, io::Printer* printer,
     const char* with_static_init, const char* without_static_init,
-    const char* var1, const string& val1,
-    const char* var2, const string& val2) {
+    const char* var1, const string& val1, const char* var2,
+    const string& val2) {
   map<string, string> vars;
   if (var1) {
     vars[var1] = val1;
@@ -510,14 +513,16 @@ void PrintHandlingOptionalStaticInitializers(
     vars[var2] = val2;
   }
   PrintHandlingOptionalStaticInitializers(
-      vars, file, printer, with_static_init, without_static_init);
+      vars, file, options, printer, with_static_init, without_static_init);
 }
 
-void PrintHandlingOptionalStaticInitializers(
-    const map<string, string>& vars, const FileDescriptor* file,
-    io::Printer* printer, const char* with_static_init,
-    const char* without_static_init) {
-  if (StaticInitializersForced(file)) {
+void PrintHandlingOptionalStaticInitializers(const map<string, string>& vars,
+                                             const FileDescriptor* file,
+                                             const Options& options,
+                                             io::Printer* printer,
+                                             const char* with_static_init,
+                                             const char* without_static_init) {
+  if (StaticInitializersForced(file, options)) {
     printer->Print(vars, with_static_init);
   } else {
     printer->Print(vars, (string(
@@ -612,10 +617,11 @@ enum Utf8CheckMode {
 };
 
 // Which level of UTF-8 enforcemant is placed on this file.
-static Utf8CheckMode GetUtf8CheckMode(const FieldDescriptor* field) {
+static Utf8CheckMode GetUtf8CheckMode(const FieldDescriptor* field,
+                                      const Options& options) {
   if (field->file()->syntax() == FileDescriptor::SYNTAX_PROTO3) {
     return STRICT;
-  } else if (field->file()->options().optimize_for() !=
+  } else if (GetOptimizeFor(field->file(), options) !=
              FileOptions::LITE_RUNTIME) {
     return VERIFY;
   } else {
@@ -624,13 +630,13 @@ static Utf8CheckMode GetUtf8CheckMode(const FieldDescriptor* field) {
 }
 
 static void GenerateUtf8CheckCode(const FieldDescriptor* field,
-                                  bool for_parse,
+                                  const Options& options, bool for_parse,
                                   const map<string, string>& variables,
                                   const char* parameters,
                                   const char* strict_function,
                                   const char* verify_function,
                                   io::Printer* printer) {
-  switch (GetUtf8CheckMode(field)) {
+  switch (GetUtf8CheckMode(field, options)) {
     case STRICT: {
       if (for_parse) {
         printer->Print("DO_(");
@@ -674,23 +680,22 @@ static void GenerateUtf8CheckCode(const FieldDescriptor* field,
 }
 
 void GenerateUtf8CheckCodeForString(const FieldDescriptor* field,
-                                    bool for_parse,
+                                    const Options& options, bool for_parse,
                                     const map<string, string>& variables,
                                     const char* parameters,
                                     io::Printer* printer) {
-  GenerateUtf8CheckCode(field, for_parse, variables, parameters,
+  GenerateUtf8CheckCode(field, options, for_parse, variables, parameters,
                         "VerifyUtf8String", "VerifyUTF8StringNamedField",
                         printer);
 }
 
 void GenerateUtf8CheckCodeForCord(const FieldDescriptor* field,
-                                  bool for_parse,
+                                  const Options& options, bool for_parse,
                                   const map<string, string>& variables,
                                   const char* parameters,
                                   io::Printer* printer) {
-  GenerateUtf8CheckCode(field, for_parse, variables, parameters,
-                        "VerifyUtf8Cord", "VerifyUTF8CordNamedField",
-                        printer);
+  GenerateUtf8CheckCode(field, options, for_parse, variables, parameters,
+                        "VerifyUtf8Cord", "VerifyUTF8CordNamedField", printer);
 }
 
 }  // namespace cpp
diff --git a/src/google/protobuf/compiler/cpp/cpp_helpers.h b/src/google/protobuf/compiler/cpp/cpp_helpers.h
index a22d414d..018acfca 100644
--- a/src/google/protobuf/compiler/cpp/cpp_helpers.h
+++ b/src/google/protobuf/compiler/cpp/cpp_helpers.h
@@ -37,8 +37,9 @@
 
 #include <map>
 #include <string>
-#include <google/protobuf/descriptor.h>
+#include <google/protobuf/compiler/cpp/cpp_options.h>
 #include <google/protobuf/descriptor.pb.h>
+#include <google/protobuf/descriptor.h>
 
 namespace google {
 namespace protobuf {
@@ -72,7 +73,7 @@ string DependentBaseClassTemplateName(const Descriptor* descriptor);
 
 // Name of the base class: either the dependent base class (for use with
 // proto_h) or google::protobuf::Message.
-string SuperClassName(const Descriptor* descriptor);
+string SuperClassName(const Descriptor* descriptor, const Options& options);
 
 // Returns a string that down-casts from the dependent base class to the
 // derived class.
@@ -118,7 +119,7 @@ string DependentTypeName(const FieldDescriptor* field);
 string FieldMessageTypeName(const FieldDescriptor* field);
 
 // Strips ".proto" or ".protodevel" from the end of a filename.
-string StripProto(const string& filename);
+LIBPROTOC_EXPORT string StripProto(const string& filename);
 
 // Get the C++ type name for a primitive type (e.g. "double", "::google::protobuf::int32", etc.).
 // Note:  non-built-in type names will be qualified, meaning they will start
@@ -168,12 +169,17 @@ inline bool PreserveUnknownFields(const Descriptor* message) {
   return message->file()->syntax() != FileDescriptor::SYNTAX_PROTO3;
 }
 
+// Returns the optimize mode for <file>, respecting <options.enforce_lite>.
+::google::protobuf::FileOptions_OptimizeMode GetOptimizeFor(
+    const FileDescriptor* file, const Options& options);
+
 // If PreserveUnknownFields() is true, determines whether unknown
 // fields will be stored in an UnknownFieldSet or a string.
 // If PreserveUnknownFields() is false, this method will not be
 // used.
-inline bool UseUnknownFieldSet(const FileDescriptor* file) {
-  return file->options().optimize_for() != FileOptions::LITE_RUNTIME;
+inline bool UseUnknownFieldSet(const FileDescriptor* file,
+                               const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
 }
 
 
@@ -186,45 +192,52 @@ bool HasEnumDefinitions(const FileDescriptor* file);
 
 // Does this file have generated parsing, serialization, and other
 // standard methods for which reflection-based fallback implementations exist?
-inline bool HasGeneratedMethods(const FileDescriptor* file) {
-  return file->options().optimize_for() != FileOptions::CODE_SIZE;
+inline bool HasGeneratedMethods(const FileDescriptor* file,
+                                const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::CODE_SIZE;
 }
 
 // Do message classes in this file have descriptor and reflection methods?
-inline bool HasDescriptorMethods(const FileDescriptor* file) {
-  return file->options().optimize_for() != FileOptions::LITE_RUNTIME;
+inline bool HasDescriptorMethods(const FileDescriptor* file,
+                                 const Options& options) {
+  return GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME;
 }
 
 // Should we generate generic services for this file?
-inline bool HasGenericServices(const FileDescriptor* file) {
+inline bool HasGenericServices(const FileDescriptor* file,
+                               const Options& options) {
   return file->service_count() > 0 &&
-         file->options().optimize_for() != FileOptions::LITE_RUNTIME &&
+         GetOptimizeFor(file, options) != FileOptions::LITE_RUNTIME &&
          file->options().cc_generic_services();
 }
 
 // Should we generate a separate, super-optimized code path for serializing to
 // flat arrays?  We don't do this in Lite mode because we'd rather reduce code
 // size.
-inline bool HasFastArraySerialization(const FileDescriptor* file) {
-  return file->options().optimize_for() == FileOptions::SPEED;
+inline bool HasFastArraySerialization(const FileDescriptor* file,
+                                      const Options& options) {
+  return GetOptimizeFor(file, options) == FileOptions::SPEED;
 }
 
 // Returns whether we have to generate code with static initializers.
-bool StaticInitializersForced(const FileDescriptor* file);
+bool StaticInitializersForced(const FileDescriptor* file,
+                              const Options& options);
 
 // Prints 'with_static_init' if static initializers have to be used for the
 // provided file. Otherwise emits both 'with_static_init' and
 // 'without_static_init' using #ifdef.
 void PrintHandlingOptionalStaticInitializers(
-    const FileDescriptor* file, io::Printer* printer,
+    const FileDescriptor* file, const Options& options, io::Printer* printer,
     const char* with_static_init, const char* without_static_init,
-    const char* var1 = NULL, const string& val1 = "",
-    const char* var2 = NULL, const string& val2 = "");
+    const char* var1 = NULL, const string& val1 = "", const char* var2 = NULL,
+    const string& val2 = "");
 
-void PrintHandlingOptionalStaticInitializers(
-    const map<string, string>& vars, const FileDescriptor* file,
-    io::Printer* printer, const char* with_static_init,
-    const char* without_static_init);
+void PrintHandlingOptionalStaticInitializers(const map<string, string>& vars,
+                                             const FileDescriptor* file,
+                                             const Options& options,
+                                             io::Printer* printer,
+                                             const char* with_static_init,
+                                             const char* without_static_init);
 
 
 inline bool IsMapEntryMessage(const Descriptor* descriptor) {
@@ -267,19 +280,23 @@ bool IsAnyMessage(const Descriptor* descriptor);
 
 bool IsWellKnownMessage(const FileDescriptor* descriptor);
 
-void GenerateUtf8CheckCodeForString(
-    const FieldDescriptor* field,
-    bool for_parse,
-    const map<string, string>& variables,
-    const char* parameters,
-    io::Printer* printer);
-
-void GenerateUtf8CheckCodeForCord(
-    const FieldDescriptor* field,
-    bool for_parse,
-    const map<string, string>& variables,
-    const char* parameters,
-    io::Printer* printer);
+void GenerateUtf8CheckCodeForString(const FieldDescriptor* field,
+                                    const Options& options, bool for_parse,
+                                    const map<string, string>& variables,
+                                    const char* parameters,
+                                    io::Printer* printer);
+
+void GenerateUtf8CheckCodeForCord(const FieldDescriptor* field,
+                                  const Options& options, bool for_parse,
+                                  const map<string, string>& variables,
+                                  const char* parameters, io::Printer* printer);
+
+inline ::google::protobuf::FileOptions_OptimizeMode GetOptimizeFor(
+    const FileDescriptor* file, const Options& options) {
+  return options.enforce_lite
+      ? FileOptions::LITE_RUNTIME
+      : file->options().optimize_for();
+}
 
 }  // namespace cpp
 }  // namespace compiler
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.cc b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
index e5e2f07d..f585c31b 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.cc
@@ -49,10 +49,11 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
                          const Options& options) {
   SetCommonFieldVariables(descriptor, variables, options);
   (*variables)["type"] = FieldMessageTypeName(descriptor);
-  (*variables)["stream_writer"] = (*variables)["declared_type"] +
-      (HasFastArraySerialization(descriptor->message_type()->file()) ?
-       "MaybeToArray" :
-       "");
+  (*variables)["stream_writer"] =
+      (*variables)["declared_type"] +
+      (HasFastArraySerialization(descriptor->message_type()->file(), options)
+           ? "MaybeToArray"
+           : "");
   (*variables)["full_name"] = descriptor->full_name();
 
   const FieldDescriptor* key =
@@ -83,7 +84,7 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
   (*variables)["number"] = SimpleItoa(descriptor->number());
   (*variables)["tag"] = SimpleItoa(internal::WireFormat::MakeTag(descriptor));
 
-  if (HasDescriptorMethods(descriptor->file())) {
+  if (HasDescriptorMethods(descriptor->file(), options)) {
     (*variables)["lite"] = "";
   } else {
     (*variables)["lite"] = "Lite";
@@ -98,10 +99,10 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
   }
 }
 
-MapFieldGenerator::
-MapFieldGenerator(const FieldDescriptor* descriptor,
-                  const Options& options)
-    : descriptor_(descriptor),
+MapFieldGenerator::MapFieldGenerator(const FieldDescriptor* descriptor,
+                                     const Options& options)
+    : FieldGenerator(options),
+      descriptor_(descriptor),
       dependent_field_(options.proto_h && IsFieldDependent(descriptor)) {
   SetMessageVariables(descriptor, &variables_, options);
 }
@@ -127,10 +128,10 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void MapFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-      "const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
-      "    $name$() const$deprecation$;\n"
-      "::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
-      "    mutable_$name$()$deprecation$;\n");
+      "$deprecated_attr$const ::google::protobuf::Map< $key_cpp$, $val_cpp$ >&\n"
+      "    $name$() const;\n"
+      "$deprecated_attr$::google::protobuf::Map< $key_cpp$, $val_cpp$ >*\n"
+      "    mutable_$name$();\n");
 }
 
 void MapFieldGenerator::
@@ -170,7 +171,7 @@ GenerateSwappingCode(io::Printer* printer) const {
 
 void MapFieldGenerator::
 GenerateConstructorCode(io::Printer* printer) const {
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(variables_,
         "$name$_.SetAssignDescriptorCallback(\n"
         "    protobuf_AssignDescriptorsOnce);\n"
@@ -217,7 +218,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
         "    (*mutable_$name$())[entry->key()] =\n"
         "        static_cast< $val_cpp$ >(*entry->mutable_value());\n"
         "  } else {\n");
-    if (HasDescriptorMethods(descriptor_->file())) {
+    if (HasDescriptorMethods(descriptor_->file(), options_)) {
       printer->Print(variables_,
           "    mutable_unknown_fields()"
           "->AddLengthDelimited($number$, data);\n");
@@ -238,14 +239,14 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
       descriptor_->message_type()->FindFieldByName("key");
   if (key_field->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        key_field, true, variables_,
+        key_field, options_, true, variables_,
         "entry->key().data(), entry->key().length(),\n", printer);
   }
   if (value_field->type() == FieldDescriptor::TYPE_STRING) {
-    GenerateUtf8CheckCodeForString(
-        value_field, true, variables_,
-        "entry->mutable_value()->data(),\n"
-        "entry->mutable_value()->length(),\n", printer);
+    GenerateUtf8CheckCodeForString(value_field, options_, true, variables_,
+                                   "entry->mutable_value()->data(),\n"
+                                   "entry->mutable_value()->length(),\n",
+                                   printer);
   }
 
   // If entry is allocated by arena, its desctructor should be avoided.
@@ -285,14 +286,14 @@ GenerateSerializeWithCachedSizes(io::Printer* printer) const {
   const FieldDescriptor* value_field =
       descriptor_->message_type()->FindFieldByName("value");
   if (key_field->type() == FieldDescriptor::TYPE_STRING) {
-    GenerateUtf8CheckCodeForString(
-        key_field, false, variables_,
-        "it->first.data(), it->first.length(),\n", printer);
+    GenerateUtf8CheckCodeForString(key_field, options_, false, variables_,
+                                   "it->first.data(), it->first.length(),\n",
+                                   printer);
   }
   if (value_field->type() == FieldDescriptor::TYPE_STRING) {
-    GenerateUtf8CheckCodeForString(
-        value_field, false, variables_,
-        "it->second.data(), it->second.length(),\n", printer);
+    GenerateUtf8CheckCodeForString(value_field, options_, false, variables_,
+                                   "it->second.data(), it->second.length(),\n",
+                                   printer);
   }
 
   printer->Outdent();
@@ -343,14 +344,14 @@ GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const {
   const FieldDescriptor* value_field =
       descriptor_->message_type()->FindFieldByName("value");
   if (key_field->type() == FieldDescriptor::TYPE_STRING) {
-    GenerateUtf8CheckCodeForString(
-        key_field, false, variables_,
-        "it->first.data(), it->first.length(),\n", printer);
+    GenerateUtf8CheckCodeForString(key_field, options_, false, variables_,
+                                   "it->first.data(), it->first.length(),\n",
+                                   printer);
   }
   if (value_field->type() == FieldDescriptor::TYPE_STRING) {
-    GenerateUtf8CheckCodeForString(
-        value_field, false, variables_,
-        "it->second.data(), it->second.length(),\n", printer);
+    GenerateUtf8CheckCodeForString(value_field, options_, false, variables_,
+                                   "it->second.data(), it->second.length(),\n",
+                                   printer);
   }
 
   printer->Outdent();
diff --git a/src/google/protobuf/compiler/cpp/cpp_map_field.h b/src/google/protobuf/compiler/cpp/cpp_map_field.h
index 5e205623..087dcde0 100644
--- a/src/google/protobuf/compiler/cpp/cpp_map_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_map_field.h
@@ -43,8 +43,7 @@ namespace cpp {
 
 class MapFieldGenerator : public FieldGenerator {
  public:
-  explicit MapFieldGenerator(const FieldDescriptor* descriptor,
-                             const Options& options);
+  MapFieldGenerator(const FieldDescriptor* descriptor, const Options& options);
   ~MapFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_message.cc b/src/google/protobuf/compiler/cpp/cpp_message.cc
index c3166611..da2a4c92 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message.cc
@@ -106,8 +106,8 @@ struct ExtensionRangeSorter {
 
 // Returns true if the "required" restriction check should be ignored for the
 // given field.
-inline static bool ShouldIgnoreRequiredFieldCheck(
-    const FieldDescriptor* field) {
+inline static bool ShouldIgnoreRequiredFieldCheck(const FieldDescriptor* field,
+                                                  const Options& options) {
   return false;
 }
 
@@ -116,9 +116,8 @@ inline static bool ShouldIgnoreRequiredFieldCheck(
 //
 // already_seen is used to avoid checking the same type multiple times
 // (and also to protect against recursion).
-static bool HasRequiredFields(
-    const Descriptor* type,
-    hash_set<const Descriptor*>* already_seen) {
+static bool HasRequiredFields(const Descriptor* type, const Options& options,
+                              hash_set<const Descriptor*>* already_seen) {
   if (already_seen->count(type) > 0) {
     // Since the first occurrence of a required field causes the whole
     // function to return true, we can assume that if the type is already
@@ -138,8 +137,8 @@ static bool HasRequiredFields(
       return true;
     }
     if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE &&
-        !ShouldIgnoreRequiredFieldCheck(field)) {
-      if (HasRequiredFields(field->message_type(), already_seen)) {
+        !ShouldIgnoreRequiredFieldCheck(field, options)) {
+      if (HasRequiredFields(field->message_type(), options, already_seen)) {
         return true;
       }
     }
@@ -148,9 +147,9 @@ static bool HasRequiredFields(
   return false;
 }
 
-static bool HasRequiredFields(const Descriptor* type) {
+static bool HasRequiredFields(const Descriptor* type, const Options& options) {
   hash_set<const Descriptor*> already_seen;
-  return HasRequiredFields(type, &already_seen);
+  return HasRequiredFields(type, options, &already_seen);
 }
 
 // This returns an estimate of the compiler's alignment for the field.  This
@@ -480,7 +479,7 @@ GenerateDependentFieldAccessorDeclarations(io::Printer* printer) {
       // If the message is dependent, the inline clear_*() method will need
       // to delete the message type, so it must be in the dependent base
       // class. (See also GenerateFieldAccessorDeclarations.)
-      printer->Print(vars, "void clear_$name$()$deprecation$;\n");
+      printer->Print(vars, "$deprecated_attr$void clear_$name$();\n");
     }
     // Generate type-specific accessor declarations.
     field_generators_.get(field).GenerateDependentAccessorDeclarations(printer);
@@ -515,22 +514,24 @@ GenerateFieldAccessorDeclarations(io::Printer* printer) {
     }
 
     if (field->is_repeated()) {
-      printer->Print(vars, "int $name$_size() const$deprecation$;\n");
+      printer->Print(vars, "$deprecated_attr$int $name$_size() const;\n");
     } else if (HasHasMethod(field)) {
-      printer->Print(vars, "bool has_$name$() const$deprecation$;\n");
+      printer->Print(vars, "$deprecated_attr$bool has_$name$() const;\n");
     } else if (HasPrivateHasMethod(field)) {
       printer->Print(vars,
           "private:\n"
-          "bool has_$name$() const$deprecation$;\n"
+          "bool has_$name$() const;\n"
           "public:\n");
     }
 
     if (!dependent_field) {
       // If this field is dependent, then its clear_() method is in the
       // depenent base class. (See also GenerateDependentAccessorDeclarations.)
-      printer->Print(vars, "void clear_$name$()$deprecation$;\n");
+      printer->Print(vars, "$deprecated_attr$void clear_$name$();\n");
     }
-    printer->Print(vars, "static const int $constant_name$ = $number$;\n");
+    printer->Print(vars,
+                   "$deprecated_attr$static const int $constant_name$ = "
+                   "$number$;\n");
 
     // Generate type-specific accessor declarations.
     field_generators_.get(field).GenerateAccessorDeclarations(printer);
@@ -837,7 +838,7 @@ GenerateDependentBaseClassDefinition(io::Printer* printer) {
 
   map<string, string> vars;
   vars["classname"] = DependentBaseClassTemplateName(descriptor_);
-  vars["superclass"] = SuperClassName(descriptor_);
+  vars["superclass"] = SuperClassName(descriptor_, options_);
 
   printer->Print(vars,
     "template <class T>\n"
@@ -888,7 +889,7 @@ GenerateClassDefinition(io::Printer* printer) {
     vars["superclass"] =
         DependentBaseClassTemplateName(descriptor_) + "<" + classname_ + ">";
   } else {
-    vars["superclass"] = SuperClassName(descriptor_);
+    vars["superclass"] = SuperClassName(descriptor_, options_);
   }
   printer->Print(vars,
     "class $dllexport$$classname$ : public $superclass$ {\n");
@@ -912,7 +913,7 @@ GenerateClassDefinition(io::Printer* printer) {
     "\n");
 
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "inline const ::google::protobuf::UnknownFieldSet& unknown_fields() const {\n"
         "  return _internal_metadata_.unknown_fields();\n"
@@ -966,7 +967,7 @@ GenerateClassDefinition(io::Printer* printer) {
   }
 
   // Only generate this member if it's not disabled.
-  if (HasDescriptorMethods(descriptor_->file()) &&
+  if (HasDescriptorMethods(descriptor_->file(), options_) &&
       !descriptor_->options().no_standard_descriptor_accessor()) {
     printer->Print(vars,
       "static const ::google::protobuf::Descriptor* descriptor();\n");
@@ -1003,7 +1004,7 @@ GenerateClassDefinition(io::Printer* printer) {
         "\n");
   }
 
-  if (!StaticInitializersForced(descriptor_->file())) {
+  if (!StaticInitializersForced(descriptor_->file(), options_)) {
     printer->Print(vars,
       "#ifdef GOOGLE_PROTOBUF_NO_STATIC_INITIALIZER\n"
       "// Returns the internal default instance pointer. This function can\n"
@@ -1046,8 +1047,8 @@ GenerateClassDefinition(io::Printer* printer) {
     "\n"
     "$classname$* New(::google::protobuf::Arena* arena) const;\n");
 
-  if (HasGeneratedMethods(descriptor_->file())) {
-    if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasGeneratedMethods(descriptor_->file(), options_)) {
+    if (HasDescriptorMethods(descriptor_->file(), options_)) {
       printer->Print(vars,
         "void CopyFrom(const ::google::protobuf::Message& from);\n"
         "void MergeFrom(const ::google::protobuf::Message& from);\n");
@@ -1069,11 +1070,11 @@ GenerateClassDefinition(io::Printer* printer) {
       "    ::google::protobuf::io::CodedOutputStream* output) const;\n");
     // DiscardUnknownFields() is implemented in message.cc using reflections. We
     // need to implement this function in generated code for messages.
-    if (!UseUnknownFieldSet(descriptor_->file())) {
+    if (!UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "void DiscardUnknownFields();\n");
     }
-    if (HasFastArraySerialization(descriptor_->file())) {
+    if (HasFastArraySerialization(descriptor_->file(), options_)) {
       printer->Print(
         "::google::protobuf::uint8* SerializeWithCachedSizesToArray(::google::protobuf::uint8* output) const;\n");
     }
@@ -1096,7 +1097,7 @@ GenerateClassDefinition(io::Printer* printer) {
   }
   uses_string_ = false;
   if (PreserveUnknownFields(descriptor_) &&
-      !UseUnknownFieldSet(descriptor_->file())) {
+      !UseUnknownFieldSet(descriptor_->file(), options_)) {
     uses_string_ = true;
   }
   for (int i = 0; i < descriptors.size(); i++) {
@@ -1126,7 +1127,7 @@ GenerateClassDefinition(io::Printer* printer) {
       "classname", classname_);
   }
 
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(
       "private:\n"
       "inline ::google::protobuf::Arena* GetArenaNoVirtual() const {\n"
@@ -1150,7 +1151,7 @@ GenerateClassDefinition(io::Printer* printer) {
       "\n");
   }
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(
       "::google::protobuf::Metadata GetMetadata() const;\n"
       "\n");
@@ -1239,7 +1240,7 @@ GenerateClassDefinition(io::Printer* printer) {
         "oneof_name", descriptor_->oneof_decl(i)->name());
   }
 
-  if (HasGeneratedMethods(descriptor_->file()) &&
+  if (HasGeneratedMethods(descriptor_->file(), options_) &&
       !descriptor_->options().message_set_wire_format() &&
       num_required_fields_ > 1) {
     printer->Print(
@@ -1281,7 +1282,7 @@ GenerateClassDefinition(io::Printer* printer) {
       "\n");
   }
 
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(
       "::google::protobuf::internal::InternalMetadataWithArena _internal_metadata_;\n");
   } else {
@@ -1408,15 +1409,14 @@ GenerateClassDefinition(io::Printer* printer) {
   // friends so that they can access private static variables like
   // default_instance_ and reflection_.
   PrintHandlingOptionalStaticInitializers(
-    descriptor_->file(), printer,
-    // With static initializers.
-    "friend void $dllexport_decl$ $adddescriptorsname$();\n",
-    // Without.
-    "friend void $dllexport_decl$ $adddescriptorsname$_impl();\n",
-    // Vars.
-    "dllexport_decl", options_.dllexport_decl,
-    "adddescriptorsname",
-    GlobalAddDescriptorsName(descriptor_->file()->name()));
+      descriptor_->file(), options_, printer,
+      // With static initializers.
+      "friend void $dllexport_decl$ $adddescriptorsname$();\n",
+      // Without.
+      "friend void $dllexport_decl$ $adddescriptorsname$_impl();\n",
+      // Vars.
+      "dllexport_decl", options_.dllexport_decl, "adddescriptorsname",
+      GlobalAddDescriptorsName(descriptor_->file()->name()));
 
   printer->Print(
     "friend void $assigndescriptorsname$();\n"
@@ -1579,7 +1579,7 @@ GenerateDescriptorInitializer(io::Printer* printer, int index) {
   // Unknown field offset: either points to the unknown field set if embedded
   // directly, or indicates that the unknown field set is stored as part of the
   // internal metadata if not.
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(vars,
     "    -1,\n");
   } else {
@@ -1619,7 +1619,7 @@ GenerateDescriptorInitializer(io::Printer* printer, int index) {
   // arena pointer and unknown field set (in a space-efficient way) if we use
   // that implementation strategy, or an offset directly to the arena pointer if
   // not (because e.g. we don't have an unknown field set).
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(vars,
     "    GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET("
     "$classname$, _internal_metadata_),\n");
@@ -1709,7 +1709,7 @@ GenerateDefaultInstanceAllocator(io::Printer* printer) {
     "classname", classname_);
 
   if ((descriptor_->oneof_decl_count() > 0) &&
-      HasDescriptorMethods(descriptor_->file())) {
+      HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(
     "$classname$_default_oneof_instance_ = new $classname$OneofInstance();\n",
     "classname", classname_);
@@ -1749,7 +1749,7 @@ GenerateShutdownCode(io::Printer* printer) {
     "delete $classname$::default_instance_;\n",
     "classname", classname_);
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     if (descriptor_->oneof_decl_count() > 0) {
       printer->Print(
         "delete $classname$_default_oneof_instance_;\n",
@@ -1777,7 +1777,8 @@ void MessageGenerator::
 GenerateClassMethods(io::Printer* printer) {
   // mutable_unknown_fields wrapper function for LazyStringOutputStream
   // callback.
-  if (!UseUnknownFieldSet(descriptor_->file())) {
+  if (PreserveUnknownFields(descriptor_) &&
+      !UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(
         "static ::std::string* MutableUnknownFieldsFor$classname$(\n"
         "    $classname$* ptr) {\n"
@@ -1851,7 +1852,7 @@ GenerateClassMethods(io::Printer* printer) {
     printer->Print("\n");
   }
 
-  if (HasGeneratedMethods(descriptor_->file())) {
+  if (HasGeneratedMethods(descriptor_->file(), options_)) {
     GenerateClear(printer);
     printer->Print("\n");
 
@@ -1861,7 +1862,7 @@ GenerateClassMethods(io::Printer* printer) {
     GenerateSerializeWithCachedSizes(printer);
     printer->Print("\n");
 
-    if (HasFastArraySerialization(descriptor_->file())) {
+    if (HasFastArraySerialization(descriptor_->file(), options_)) {
       GenerateSerializeWithCachedSizesToArray(printer);
       printer->Print("\n");
     }
@@ -1882,7 +1883,7 @@ GenerateClassMethods(io::Printer* printer) {
   GenerateSwap(printer);
   printer->Print("\n");
 
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     printer->Print(
       "::google::protobuf::Metadata $classname$::GetMetadata() const {\n"
       "  protobuf_AssignDescriptorsOnce();\n"
@@ -1959,7 +1960,7 @@ GenerateSharedConstructorCode(io::Printer* printer) {
       "_cached_size_ = 0;\n").c_str());
 
   if (PreserveUnknownFields(descriptor_) &&
-      !UseUnknownFieldSet(descriptor_->file())) {
+      !UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(
         "_unknown_fields_.UnsafeSetDefault(\n"
         "    &::google::protobuf::internal::GetEmptyStringAlreadyInited());\n");
@@ -2004,7 +2005,7 @@ GenerateSharedDestructorCode(io::Printer* printer) {
 
   // Write the desctructor for _unknown_fields_ in lite runtime.
   if (PreserveUnknownFields(descriptor_) &&
-      !UseUnknownFieldSet(descriptor_->file())) {
+      !UseUnknownFieldSet(descriptor_->file(), options_)) {
     if (SupportsArenas(descriptor_)) {
       printer->Print(
           "_unknown_fields_.Destroy(\n"
@@ -2035,11 +2036,11 @@ GenerateSharedDestructorCode(io::Printer* printer) {
   }
 
   PrintHandlingOptionalStaticInitializers(
-    descriptor_->file(), printer,
-    // With static initializers.
-    "if (this != default_instance_) {\n",
-    // Without.
-    "if (this != &default_instance()) {\n");
+      descriptor_->file(), options_, printer,
+      // With static initializers.
+      "if (this != default_instance_) {\n",
+      // Without.
+      "if (this != &default_instance()) {\n");
 
   // We need to delete all embedded messages.
   // TODO(kenton):  If we make unset messages point at default instances
@@ -2119,7 +2120,7 @@ GenerateStructors(io::Printer* printer) {
     superclass =
         DependentBaseClassTemplateName(descriptor_) + "<" + classname_ + ">";
   } else {
-    superclass = SuperClassName(descriptor_);
+    superclass = SuperClassName(descriptor_, options_);
   }
   string initializer_with_arena = superclass + "()";
 
@@ -2127,7 +2128,7 @@ GenerateStructors(io::Printer* printer) {
     initializer_with_arena += ",\n  _extensions_(arena)";
   }
 
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     initializer_with_arena += ",\n  _internal_metadata_(arena)";
   } else {
     initializer_with_arena += ",\n  _arena_ptr_(arena)";
@@ -2147,7 +2148,7 @@ GenerateStructors(io::Printer* printer) {
   }
 
   string initializer_null;
-  initializer_null = (UseUnknownFieldSet(descriptor_->file()) ?
+  initializer_null = (UseUnknownFieldSet(descriptor_->file(), options_) ?
     ", _internal_metadata_(NULL)" : ", _arena_ptr_(NULL)");
   if (IsAnyMessage(descriptor_)) {
     initializer_null += ", _any_metadata_(&type_url_, &value_)";
@@ -2201,24 +2202,23 @@ GenerateStructors(io::Printer* printer) {
     if (!field->is_repeated() &&
         field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE &&
         (field->containing_oneof() == NULL ||
-         HasDescriptorMethods(descriptor_->file()))) {
+         HasDescriptorMethods(descriptor_->file(), options_))) {
       string name;
       if (field->containing_oneof()) {
         name = classname_ + "_default_oneof_instance_->";
       }
       name += FieldName(field);
       PrintHandlingOptionalStaticInitializers(
-        descriptor_->file(), printer,
-        // With static initializers.
-        "  $name$_ = const_cast< $type$*>(&$type$::default_instance());\n",
-        // Without.
-        "  $name$_ = const_cast< $type$*>(\n"
-        "      $type$::internal_default_instance());\n",
-        // Vars.
-        "name", name,
-        "type", FieldMessageTypeName(field));
+          descriptor_->file(), options_, printer,
+          // With static initializers.
+          "  $name$_ = const_cast< $type$*>(&$type$::default_instance());\n",
+          // Without.
+          "  $name$_ = const_cast< $type$*>(\n"
+          "      $type$::internal_default_instance());\n",
+          // Vars.
+          "name", name, "type", FieldMessageTypeName(field));
     } else if (field->containing_oneof() &&
-               HasDescriptorMethods(descriptor_->file())) {
+               HasDescriptorMethods(descriptor_->file(), options_)) {
       field_generators_.get(descriptor_->field(i))
           .GenerateConstructorCode(printer);
     }
@@ -2234,10 +2234,10 @@ GenerateStructors(io::Printer* printer) {
     "classname", classname_,
     "superclass", superclass,
     "full_name", descriptor_->full_name());
-  if (UseUnknownFieldSet(descriptor_->file())) {
+  if (UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(
         ",\n    _internal_metadata_(NULL)");
-  } else if (!UseUnknownFieldSet(descriptor_->file())) {
+  } else if (!UseUnknownFieldSet(descriptor_->file(), options_)) {
     printer->Print(",\n    _arena_ptr_(NULL)");
   }
   if (IsAnyMessage(descriptor_)) {
@@ -2285,7 +2285,7 @@ GenerateStructors(io::Printer* printer) {
     "classname", classname_);
 
   // Only generate this member if it's not disabled.
-  if (HasDescriptorMethods(descriptor_->file()) &&
+  if (HasDescriptorMethods(descriptor_->file(), options_) &&
       !descriptor_->options().no_standard_descriptor_accessor()) {
     printer->Print(
       "const ::google::protobuf::Descriptor* $classname$::descriptor() {\n"
@@ -2303,14 +2303,14 @@ GenerateStructors(io::Printer* printer) {
     "classname", classname_);
 
   PrintHandlingOptionalStaticInitializers(
-    descriptor_->file(), printer,
-    // With static initializers.
-    "  if (default_instance_ == NULL) $adddescriptorsname$();\n",
-    // Without.
-    "  $adddescriptorsname$();\n",
-    // Vars.
-    "adddescriptorsname",
-    GlobalAddDescriptorsName(descriptor_->file()->name()));
+      descriptor_->file(), options_, printer,
+      // With static initializers.
+      "  if (default_instance_ == NULL) $adddescriptorsname$();\n",
+      // Without.
+      "  $adddescriptorsname$();\n",
+      // Vars.
+      "adddescriptorsname",
+      GlobalAddDescriptorsName(descriptor_->file()->name()));
 
   printer->Print(
     "  return *default_instance_;\n"
@@ -2352,8 +2352,10 @@ static int popcnt(uint32 n) {
 
 void MessageGenerator::
 GenerateClear(io::Printer* printer) {
-  printer->Print("void $classname$::Clear() {\n",
-                 "classname", classname_);
+  printer->Print(
+      "void $classname$::Clear() {\n"
+      "// @@protoc_insertion_point(message_clear_start:$full_name$)\n",
+      "classname", classname_, "full_name", descriptor_->full_name());
   printer->Indent();
 
   // Step 1: Extensions
@@ -2390,8 +2392,16 @@ GenerateClear(io::Printer* printer) {
   // positions of two fields in the Message.
   // ZR_ zeroes a non-empty range of fields via memset.
   const char* macros =
+      "#if defined(__clang__)\n"
+      "#define ZR_HELPER_(f) \\\n"
+      "  _Pragma(\"clang diagnostic push\") \\\n"
+      "  _Pragma(\"clang diagnostic ignored \\\"-Winvalid-offsetof\\\"\") \\\n"
+      "  __builtin_offsetof($classname$, f) \\\n"
+      "  _Pragma(\"clang diagnostic pop\")\n"
+      "#else\n"
       "#define ZR_HELPER_(f) reinterpret_cast<char*>(\\\n"
-      "  &reinterpret_cast<$classname$*>(16)->f)\n\n"
+      "  &reinterpret_cast<$classname$*>(16)->f)\n"
+      "#endif\n\n"
       "#define ZR_(first, last) do {\\\n"
       "  ::memset(&first, 0,\\\n"
       "           ZR_HELPER_(last) - ZR_HELPER_(first) + sizeof(last));\\\n"
@@ -2519,7 +2529,7 @@ GenerateClear(io::Printer* printer) {
   }
 
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "if (_internal_metadata_.have_unknown_fields()) {\n"
         "  mutable_unknown_fields()->Clear();\n"
@@ -2549,10 +2559,13 @@ GenerateOneofClear(io::Printer* printer) {
     map<string, string> oneof_vars;
     oneof_vars["classname"] = classname_;
     oneof_vars["oneofname"] = descriptor_->oneof_decl(i)->name();
+    oneof_vars["full_name"] = descriptor_->full_name();
     string message_class;
 
     printer->Print(oneof_vars,
-        "void $classname$::clear_$oneofname$() {\n");
+                   "void $classname$::clear_$oneofname$() {\n"
+                   "// @@protoc_insertion_point(one_of_clear_start:"
+                   "$full_name$)\n");
     printer->Indent();
     printer->Print(oneof_vars,
         "switch($oneofname$_case()) {\n");
@@ -2635,7 +2648,7 @@ GenerateSwap(io::Printer* printer) {
                  "classname", classname_);
   printer->Indent();
 
-  if (HasGeneratedMethods(descriptor_->file())) {
+  if (HasGeneratedMethods(descriptor_->file(), options_)) {
     for (int i = 0; i < descriptor_->field_count(); i++) {
       const FieldDescriptor* field = descriptor_->field(i);
       field_generators_.get(field).GenerateSwappingCode(printer);
@@ -2656,19 +2669,15 @@ GenerateSwap(io::Printer* printer) {
       }
     }
 
-    if (PreserveUnknownFields(descriptor_)) {
-      if (UseUnknownFieldSet(descriptor_->file())) {
-        printer->Print(
+    // Ignore PreserveUnknownFields here - always swap internal_metadata as it
+    // may contain more than just unknown fields.
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
+      printer->Print(
           "_internal_metadata_.Swap(&other->_internal_metadata_);\n");
-      } else {
-        printer->Print("_unknown_fields_.Swap(&other->_unknown_fields_);\n");
-      }
     } else {
-      // Still swap internal_metadata as it may contain more than just
-      // unknown fields.
-      printer->Print(
-        "_internal_metadata_.Swap(&other->_internal_metadata_);\n");
+      printer->Print("_unknown_fields_.Swap(&other->_unknown_fields_);\n");
     }
+
     printer->Print("std::swap(_cached_size_, other->_cached_size_);\n");
     if (descriptor_->extension_range_count() > 0) {
       printer->Print("_extensions_.Swap(&other->_extensions_);\n");
@@ -2683,13 +2692,15 @@ GenerateSwap(io::Printer* printer) {
 
 void MessageGenerator::
 GenerateMergeFrom(io::Printer* printer) {
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     // Generate the generalized MergeFrom (aka that which takes in the Message
     // base class as a parameter).
     printer->Print(
-      "void $classname$::MergeFrom(const ::google::protobuf::Message& from) {\n"
-      "  if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);\n",
-      "classname", classname_);
+        "void $classname$::MergeFrom(const ::google::protobuf::Message& from) {\n"
+        "// @@protoc_insertion_point(generalized_merge_from_start:"
+        "$full_name$)\n"
+        "  if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);\n",
+        "classname", classname_, "full_name", descriptor_->full_name());
     printer->Indent();
 
     // Cast the message to the proper type. If we find that the message is
@@ -2701,11 +2712,15 @@ GenerateMergeFrom(io::Printer* printer) {
       "    ::google::protobuf::internal::DynamicCastToGenerated<const $classname$>(\n"
       "        &from);\n"
       "if (source == NULL) {\n"
+      "// @@protoc_insertion_point(generalized_merge_from_cast_fail:"
+      "$full_name$)\n"
       "  ::google::protobuf::internal::ReflectionOps::Merge(from, this);\n"
       "} else {\n"
+      "// @@protoc_insertion_point(generalized_merge_from_cast_success:"
+      "$full_name$)\n"
       "  MergeFrom(*source);\n"
       "}\n",
-      "classname", classname_);
+      "classname", classname_, "full_name", descriptor_->full_name());
 
     printer->Outdent();
     printer->Print("}\n\n");
@@ -2722,9 +2737,11 @@ GenerateMergeFrom(io::Printer* printer) {
 
   // Generate the class-specific MergeFrom, which avoids the GOOGLE_CHECK and cast.
   printer->Print(
-    "void $classname$::MergeFrom(const $classname$& from) {\n"
-    "  if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);\n",
-    "classname", classname_);
+      "void $classname$::MergeFrom(const $classname$& from) {\n"
+      "// @@protoc_insertion_point(class_specific_merge_from_start:"
+      "$full_name$)\n"
+      "  if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);\n",
+      "classname", classname_, "full_name", descriptor_->full_name());
   printer->Indent();
 
   // Merge Repeated fields. These fields do not require a
@@ -2825,7 +2842,7 @@ GenerateMergeFrom(io::Printer* printer) {
   }
 
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "if (from._internal_metadata_.have_unknown_fields()) {\n"
         "  mutable_unknown_fields()->MergeFrom(from.unknown_fields());\n"
@@ -2844,12 +2861,14 @@ GenerateMergeFrom(io::Printer* printer) {
 
 void MessageGenerator::
 GenerateCopyFrom(io::Printer* printer) {
-  if (HasDescriptorMethods(descriptor_->file())) {
+  if (HasDescriptorMethods(descriptor_->file(), options_)) {
     // Generate the generalized CopyFrom (aka that which takes in the Message
     // base class as a parameter).
     printer->Print(
-      "void $classname$::CopyFrom(const ::google::protobuf::Message& from) {\n",
-      "classname", classname_);
+        "void $classname$::CopyFrom(const ::google::protobuf::Message& from) {\n"
+        "// @@protoc_insertion_point(generalized_copy_from_start:"
+        "$full_name$)\n",
+        "classname", classname_, "full_name", descriptor_->full_name());
     printer->Indent();
 
     printer->Print(
@@ -2863,8 +2882,10 @@ GenerateCopyFrom(io::Printer* printer) {
 
   // Generate the class-specific CopyFrom.
   printer->Print(
-    "void $classname$::CopyFrom(const $classname$& from) {\n",
-    "classname", classname_);
+      "void $classname$::CopyFrom(const $classname$& from) {\n"
+      "// @@protoc_insertion_point(class_specific_copy_from_start:"
+      "$full_name$)\n",
+      "classname", classname_, "full_name", descriptor_->full_name());
   printer->Indent();
 
   printer->Print(
@@ -2886,15 +2907,15 @@ GenerateMergeFromCodedStream(io::Printer* printer) {
       "classname", classname_);
 
     PrintHandlingOptionalStaticInitializers(
-      descriptor_->file(), printer,
-      // With static initializers.
-      "  return _extensions_.ParseMessageSet(input, default_instance_,\n"
-      "                                      mutable_unknown_fields());\n",
-      // Without.
-      "  return _extensions_.ParseMessageSet(input, &default_instance(),\n"
-      "                                      mutable_unknown_fields());\n",
-      // Vars.
-      "classname", classname_);
+        descriptor_->file(), options_, printer,
+        // With static initializers.
+        "  return _extensions_.ParseMessageSet(input, default_instance_,\n"
+        "                                      mutable_unknown_fields());\n",
+        // Without.
+        "  return _extensions_.ParseMessageSet(input, &default_instance(),\n"
+        "                                      mutable_unknown_fields());\n",
+        // Vars.
+        "classname", classname_);
 
     printer->Print(
       "}\n");
@@ -2904,17 +2925,18 @@ GenerateMergeFromCodedStream(io::Printer* printer) {
   printer->Print(
     "bool $classname$::MergePartialFromCodedStream(\n"
     "    ::google::protobuf::io::CodedInputStream* input) {\n"
-    "#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure\n"
+    "#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure\n"
     "  ::google::protobuf::uint32 tag;\n",
     "classname", classname_);
 
-  if (!UseUnknownFieldSet(descriptor_->file())) {
+  if (PreserveUnknownFields(descriptor_) &&
+      !UseUnknownFieldSet(descriptor_->file(), options_)) {
     // Use LazyStringOutputString to avoid initializing unknown fields string
     // unless it is actually needed. For the same reason, disable eager refresh
     // on the CodedOutputStream.
     printer->Print(
       "  ::google::protobuf::io::LazyStringOutputStream unknown_fields_string(\n"
-      "      google::protobuf::internal::NewPermanentCallback(\n"
+      "      ::google::protobuf::internal::NewPermanentCallback(\n"
       "          &MutableUnknownFieldsFor$classname$, this));\n"
       "  ::google::protobuf::io::CodedOutputStream unknown_fields_stream(\n"
       "      &unknown_fields_string, false);\n",
@@ -3136,32 +3158,32 @@ GenerateMergeFromCodedStream(io::Printer* printer) {
     }
     printer->Print(") {\n");
     if (PreserveUnknownFields(descriptor_)) {
-      if (UseUnknownFieldSet(descriptor_->file())) {
+      if (UseUnknownFieldSet(descriptor_->file(), options_)) {
         PrintHandlingOptionalStaticInitializers(
-          descriptor_->file(), printer,
-          // With static initializers.
-          "  DO_(_extensions_.ParseField(tag, input, default_instance_,\n"
-          "                              mutable_unknown_fields()));\n",
-          // Without.
-          "  DO_(_extensions_.ParseField(tag, input, &default_instance(),\n"
-          "                              mutable_unknown_fields()));\n");
+            descriptor_->file(), options_, printer,
+            // With static initializers.
+            "  DO_(_extensions_.ParseField(tag, input, default_instance_,\n"
+            "                              mutable_unknown_fields()));\n",
+            // Without.
+            "  DO_(_extensions_.ParseField(tag, input, &default_instance(),\n"
+            "                              mutable_unknown_fields()));\n");
       } else {
         PrintHandlingOptionalStaticInitializers(
-          descriptor_->file(), printer,
-          // With static initializers.
-          "  DO_(_extensions_.ParseField(tag, input, default_instance_,\n"
-          "                              &unknown_fields_stream));\n",
-          // Without.
-          "  DO_(_extensions_.ParseField(tag, input, &default_instance(),\n"
-          "                              &unknown_fields_stream));\n");
+            descriptor_->file(), options_, printer,
+            // With static initializers.
+            "  DO_(_extensions_.ParseField(tag, input, default_instance_,\n"
+            "                              &unknown_fields_stream));\n",
+            // Without.
+            "  DO_(_extensions_.ParseField(tag, input, &default_instance(),\n"
+            "                              &unknown_fields_stream));\n");
       }
     } else {
       PrintHandlingOptionalStaticInitializers(
-        descriptor_->file(), printer,
-        // With static initializers.
-        "  DO_(_extensions_.ParseField(tag, input, default_instance_);\n",
-        // Without.
-        "  DO_(_extensions_.ParseField(tag, input, &default_instance());\n");
+          descriptor_->file(), options_, printer,
+          // With static initializers.
+          "  DO_(_extensions_.ParseField(tag, input, default_instance_);\n",
+          // Without.
+          "  DO_(_extensions_.ParseField(tag, input, &default_instance());\n");
     }
     printer->Print(
       "  continue;\n"
@@ -3170,7 +3192,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) {
 
   // We really don't recognize this tag.  Skip it.
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "DO_(::google::protobuf::internal::WireFormat::SkipField(\n"
         "      input, tag, mutable_unknown_fields()));\n");
@@ -3263,7 +3285,7 @@ GenerateSerializeWithCachedSizes(io::Printer* printer) {
       "    ::google::protobuf::io::CodedOutputStream* output) const {\n"
       "  _extensions_.SerializeMessageSetWithCachedSizes(output);\n",
       "classname", classname_);
-    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file()));
+    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file(), options_));
     printer->Print(
       "  ::google::protobuf::internal::WireFormat::SerializeUnknownMessageSetItems(\n"
       "      unknown_fields(), output);\n");
@@ -3303,7 +3325,7 @@ GenerateSerializeWithCachedSizesToArray(io::Printer* printer) {
       "  target =\n"
       "      _extensions_.SerializeMessageSetWithCachedSizesToArray(target);\n",
       "classname", classname_);
-    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file()));
+    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file(), options_));
     printer->Print(
       "  target = ::google::protobuf::internal::WireFormat::\n"
       "             SerializeUnknownMessageSetItemsToArray(\n"
@@ -3369,7 +3391,7 @@ GenerateSerializeWithCachedSizesBody(io::Printer* printer, bool to_array) {
   }
 
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print("if (_internal_metadata_.have_unknown_fields()) {\n");
       printer->Indent();
       if (to_array) {
@@ -3436,10 +3458,11 @@ GenerateByteSize(io::Printer* printer) {
   if (descriptor_->options().message_set_wire_format()) {
     // Special-case MessageSet.
     printer->Print(
-      "int $classname$::ByteSize() const {\n"
-      "  int total_size = _extensions_.MessageSetByteSize();\n",
-      "classname", classname_);
-    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file()));
+        "int $classname$::ByteSize() const {\n"
+        "// @@protoc_insertion_point(message_set_byte_size_start:$full_name$)\n"
+        "  int total_size = _extensions_.MessageSetByteSize();\n",
+        "classname", classname_, "full_name", descriptor_->full_name());
+    GOOGLE_CHECK(UseUnknownFieldSet(descriptor_->file(), options_));
     printer->Print(
       "if (_internal_metadata_.have_unknown_fields()) {\n"
       "  total_size += ::google::protobuf::internal::WireFormat::\n"
@@ -3458,8 +3481,10 @@ GenerateByteSize(io::Printer* printer) {
     // Emit a function (rarely used, we hope) that handles the required fields
     // by checking for each one individually.
     printer->Print(
-        "int $classname$::RequiredFieldsByteSizeFallback() const {\n",
-        "classname", classname_);
+        "int $classname$::RequiredFieldsByteSizeFallback() const {\n"
+        "// @@protoc_insertion_point(required_fields_byte_size_fallback_start:"
+        "$full_name$)\n",
+        "classname", classname_, "full_name", descriptor_->full_name());
     printer->Indent();
     printer->Print("int total_size = 0;\n");
     for (int i = 0; i < descriptor_->field_count(); i++) {
@@ -3482,8 +3507,9 @@ GenerateByteSize(io::Printer* printer) {
   }
 
   printer->Print(
-    "int $classname$::ByteSize() const {\n",
-    "classname", classname_);
+      "int $classname$::ByteSize() const {\n"
+      "// @@protoc_insertion_point(message_byte_size_start:$full_name$)\n",
+      "classname", classname_, "full_name", descriptor_->full_name());
   printer->Indent();
   printer->Print(
     "int total_size = 0;\n"
@@ -3659,7 +3685,7 @@ GenerateByteSize(io::Printer* printer) {
   }
 
   if (PreserveUnknownFields(descriptor_)) {
-    if (UseUnknownFieldSet(descriptor_->file())) {
+    if (UseUnknownFieldSet(descriptor_->file(), options_)) {
       printer->Print(
         "if (_internal_metadata_.have_unknown_fields()) {\n"
         "  total_size +=\n"
@@ -3725,8 +3751,8 @@ GenerateIsInitialized(io::Printer* printer) {
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor* field = descriptor_->field(i);
     if (field->cpp_type() == FieldDescriptor::CPPTYPE_MESSAGE &&
-        !ShouldIgnoreRequiredFieldCheck(field) &&
-        HasRequiredFields(field->message_type())) {
+        !ShouldIgnoreRequiredFieldCheck(field, options_) &&
+        HasRequiredFields(field->message_type(), options_)) {
       if (field->is_repeated()) {
         printer->Print(
           "if (!::google::protobuf::internal::AllAreInitialized(this->$name$()))"
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.cc b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
index b4545892..332c0264 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.cc
@@ -53,10 +53,11 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
     (*variables)["non_null_ptr_to_name"] =
         StrCat("this->", (*variables)["name"], "_");
   }
-  (*variables)["stream_writer"] = (*variables)["declared_type"] +
-      (HasFastArraySerialization(descriptor->message_type()->file()) ?
-       "MaybeToArray" :
-       "");
+  (*variables)["stream_writer"] =
+      (*variables)["declared_type"] +
+      (HasFastArraySerialization(descriptor->message_type()->file(), options)
+           ? "MaybeToArray"
+           : "");
   // NOTE: Escaped here to unblock proto1->proto2 migration.
   // TODO(liujisi): Extend this to apply for other conflicting methods.
   (*variables)["release_name"] =
@@ -77,11 +78,11 @@ void SetMessageVariables(const FieldDescriptor* descriptor,
 
 // ===================================================================
 
-MessageFieldGenerator::
-MessageFieldGenerator(const FieldDescriptor* descriptor,
-                      const Options& options)
-  : descriptor_(descriptor),
-    dependent_field_(options.proto_h && IsFieldDependent(descriptor)) {
+MessageFieldGenerator::MessageFieldGenerator(const FieldDescriptor* descriptor,
+                                             const Options& options)
+    : FieldGenerator(options),
+      descriptor_(descriptor),
+      dependent_field_(options.proto_h && IsFieldDependent(descriptor)) {
   SetMessageVariables(descriptor, &variables_, options);
 }
 
@@ -95,7 +96,7 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void MessageFieldGenerator::
 GenerateGetterDeclaration(io::Printer* printer) const {
   printer->Print(variables_,
-      "const $type$& $name$() const$deprecation$;\n");
+      "$deprecated_attr$const $type$& $name$() const;\n");
 }
 
 void MessageFieldGenerator::
@@ -105,9 +106,9 @@ GenerateDependentAccessorDeclarations(io::Printer* printer) const {
   }
   // Arena manipulation code is out-of-line in the derived message class.
   printer->Print(variables_,
-    "$type$* mutable_$name$()$deprecation$;\n"
-    "$type$* $release_name$()$deprecation$;\n"
-    "void set_allocated_$name$($type$* $name$)$deprecation$;\n");
+    "$deprecated_attr$$type$* mutable_$name$();\n"
+    "$deprecated_attr$$type$* $release_name$();\n"
+    "$deprecated_attr$void set_allocated_$name$($type$* $name$);\n");
 }
 
 void MessageFieldGenerator::
@@ -115,28 +116,28 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   if (SupportsArenas(descriptor_)) {
     printer->Print(variables_,
        "private:\n"
-       "void _slow_mutable_$name$()$deprecation$;\n");
+       "void _slow_mutable_$name$();\n");
     if (SupportsArenas(descriptor_->message_type())) {
       printer->Print(variables_,
        "void _slow_set_allocated_$name$(\n"
-       "    ::google::protobuf::Arena* message_arena, $type$** $name$)$deprecation$;\n");
+       "    ::google::protobuf::Arena* message_arena, $type$** $name$);\n");
     }
     printer->Print(variables_,
-       "$type$* _slow_$release_name$()$deprecation$;\n"
+       "$type$* _slow_$release_name$();\n"
        "public:\n");
   }
   GenerateGetterDeclaration(printer);
   if (!dependent_field_) {
     printer->Print(variables_,
-      "$type$* mutable_$name$()$deprecation$;\n"
-      "$type$* $release_name$()$deprecation$;\n"
-      "void set_allocated_$name$($type$* $name$)$deprecation$;\n");
+      "$deprecated_attr$$type$* mutable_$name$();\n"
+      "$deprecated_attr$$type$* $release_name$();\n"
+      "$deprecated_attr$void set_allocated_$name$($type$* $name$);\n");
   }
   if (SupportsArenas(descriptor_)) {
     printer->Print(variables_,
-      "$type$* unsafe_arena_release_$name$()$deprecation$;\n"
-      "void unsafe_arena_set_allocated_$name$(\n"
-      "    $type$* $name$)$deprecation$;\n");
+      "$deprecated_attr$$type$* unsafe_arena_release_$name$();\n"
+      "$deprecated_attr$void unsafe_arena_set_allocated_$name$(\n"
+      "    $type$* $name$);\n");
   }
 }
 
@@ -167,6 +168,7 @@ void MessageFieldGenerator::GenerateNonInlineAccessorDefinitions(
       "  }\n"
       "}\n"
       "$type$* $classname$::unsafe_arena_release_$name$() {\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  $type$* temp = $name$_;\n"
       "  $name$_ = NULL;\n"
@@ -246,6 +248,7 @@ GenerateDependentInlineAccessorDefinitions(io::Printer* printer) const {
       "}\n"
       "template <class T>\n"
       "inline $type$* $dependent_classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $dependent_typename$*& $name$_ = $this_message$$name$_;\n"
       "  $clear_hasbit$\n"
       "  if ($this_message$GetArenaNoVirtual() != NULL) {\n"
@@ -305,6 +308,7 @@ GenerateDependentInlineAccessorDefinitions(io::Printer* printer) const {
       "}\n"
       "template <class T>\n"
       "inline $type$* $dependent_classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  $dependent_typename$*& $name$_ = $this_message$$name$_;\n"
       "  $dependent_typename$* temp = $name$_;\n"
@@ -349,11 +353,11 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
     "  // @@protoc_insertion_point(field_get:$full_name$)\n");
 
   PrintHandlingOptionalStaticInitializers(
-    variables, descriptor_->file(), printer,
-    // With static initializers.
-    "  return $name$_ != NULL ? *$name$_ : *default_instance_->$name$_;\n",
-    // Without.
-    "  return $name$_ != NULL ? *$name$_ : *default_instance().$name$_;\n");
+      variables, descriptor_->file(), options_, printer,
+      // With static initializers.
+      "  return $name$_ != NULL ? *$name$_ : *default_instance_->$name$_;\n",
+      // Without.
+      "  return $name$_ != NULL ? *$name$_ : *default_instance().$name$_;\n");
   printer->Print(variables, "}\n");
 
   if (dependent_field_) {
@@ -373,6 +377,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "}\n"
       "$inline$"
       "$type$* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  if (GetArenaNoVirtual() != NULL) {\n"
       "    return _slow_$release_name$();\n"
@@ -426,6 +431,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "}\n"
       "$inline$"
       "$type$* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  $type$* temp = $name$_;\n"
       "  $name$_ = NULL;\n"
@@ -547,7 +553,7 @@ GenerateDependentAccessorDeclarations(io::Printer* printer) const {
     return;
   }
   printer->Print(variables_,
-      "const $type$& $name$() const$deprecation$;\n");
+      "$deprecated_attr$const $type$& $name$() const;\n");
   MessageFieldGenerator::GenerateDependentAccessorDeclarations(printer);
 }
 
@@ -560,7 +566,7 @@ GenerateGetterDeclaration(io::Printer* printer) const {
     return;
   }
   printer->Print(variables_,
-      "const $type$& $name$() const$deprecation$;\n");
+      "$deprecated_attr$const $type$& $name$() const;\n");
 }
 
 void MessageOneofFieldGenerator::
@@ -651,6 +657,7 @@ InternalGenerateInlineAccessorDefinitions(const map<string, string>& variables,
       "$tmpl$"
       "$inline$"
       "$type$* $dependent_classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if ($this_message$has_$name$()) {\n"
       "    $this_message$clear_has_$oneof_name$();\n"
       "    if ($this_message$GetArenaNoVirtual() != NULL) {\n"
@@ -706,6 +713,8 @@ InternalGenerateInlineAccessorDefinitions(const map<string, string>& variables,
       "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
       "}\n"
       "$inline$ $type$* $classname$::unsafe_arena_release_$name$() {\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_release"
+      ":$full_name$)\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    $type$* temp = $oneof_prefix$$name$_;\n"
@@ -744,6 +753,7 @@ InternalGenerateInlineAccessorDefinitions(const map<string, string>& variables,
       "$tmpl$"
       "$inline$"
       "$type$* $dependent_classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if ($this_message$has_$name$()) {\n"
       "    $this_message$clear_has_$oneof_name$();\n"
       "    $dependent_typename$* temp = $field_member$;\n"
@@ -805,12 +815,12 @@ GenerateConstructorCode(io::Printer* printer) const {
 
 // ===================================================================
 
-RepeatedMessageFieldGenerator::
-RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
-                              const Options& options)
-  : descriptor_(descriptor),
-    dependent_field_(options.proto_h && IsFieldDependent(descriptor)),
-    dependent_getter_(dependent_field_ && options.safe_boundary_check) {
+RepeatedMessageFieldGenerator::RepeatedMessageFieldGenerator(
+    const FieldDescriptor* descriptor, const Options& options)
+    : FieldGenerator(options),
+      descriptor_(descriptor),
+      dependent_field_(options.proto_h && IsFieldDependent(descriptor)),
+      dependent_getter_(dependent_field_ && options.safe_boundary_check) {
   SetMessageVariables(descriptor, &variables_, options);
 }
 
@@ -825,23 +835,23 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedMessageFieldGenerator::
 InternalGenerateTypeDependentAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$* mutable_$name$(int index)$deprecation$;\n"
-    "$type$* add_$name$()$deprecation$;\n");
+    "$deprecated_attr$$type$* mutable_$name$(int index);\n"
+    "$deprecated_attr$$type$* add_$name$();\n");
   if (dependent_getter_) {
     printer->Print(variables_,
-      "const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
-      "    $name$() const$deprecation$;\n");
+      "$deprecated_attr$const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
+      "    $name$() const;\n");
   }
   printer->Print(variables_,
-    "::google::protobuf::RepeatedPtrField< $type$ >*\n"
-    "    mutable_$name$()$deprecation$;\n");
+    "$deprecated_attr$::google::protobuf::RepeatedPtrField< $type$ >*\n"
+    "    mutable_$name$();\n");
 }
 
 void RepeatedMessageFieldGenerator::
 GenerateDependentAccessorDeclarations(io::Printer* printer) const {
   if (dependent_getter_) {
     printer->Print(variables_,
-      "const $type$& $name$(int index) const$deprecation$;\n");
+      "$deprecated_attr$const $type$& $name$(int index) const;\n");
   }
   if (dependent_field_) {
     InternalGenerateTypeDependentAccessorDeclarations(printer);
@@ -852,15 +862,15 @@ void RepeatedMessageFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   if (!dependent_getter_) {
     printer->Print(variables_,
-      "const $type$& $name$(int index) const$deprecation$;\n");
+      "$deprecated_attr$const $type$& $name$(int index) const;\n");
   }
   if (!dependent_field_) {
     InternalGenerateTypeDependentAccessorDeclarations(printer);
   }
   if (!dependent_getter_) {
     printer->Print(variables_,
-      "const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
-      "    $name$() const$deprecation$;\n");
+      "$deprecated_attr$const ::google::protobuf::RepeatedPtrField< $type$ >&\n"
+      "    $name$() const;\n");
   }
 }
 
diff --git a/src/google/protobuf/compiler/cpp/cpp_message_field.h b/src/google/protobuf/compiler/cpp/cpp_message_field.h
index 35efd0fa..d8d9279c 100644
--- a/src/google/protobuf/compiler/cpp/cpp_message_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_message_field.h
@@ -46,8 +46,8 @@ namespace cpp {
 
 class MessageFieldGenerator : public FieldGenerator {
  public:
-  explicit MessageFieldGenerator(const FieldDescriptor* descriptor,
-                                 const Options& options);
+  MessageFieldGenerator(const FieldDescriptor* descriptor,
+                        const Options& options);
   ~MessageFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -83,8 +83,8 @@ class MessageFieldGenerator : public FieldGenerator {
 
 class MessageOneofFieldGenerator : public MessageFieldGenerator {
  public:
-  explicit MessageOneofFieldGenerator(const FieldDescriptor* descriptor,
-                                      const Options& options);
+  MessageOneofFieldGenerator(const FieldDescriptor* descriptor,
+                             const Options& options);
   ~MessageOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -110,8 +110,8 @@ class MessageOneofFieldGenerator : public MessageFieldGenerator {
 
 class RepeatedMessageFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
-                                         const Options& options);
+  RepeatedMessageFieldGenerator(const FieldDescriptor* descriptor,
+                                const Options& options);
   ~RepeatedMessageFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_options.h b/src/google/protobuf/compiler/cpp/cpp_options.h
index e908362b..ab1d2ed3 100644
--- a/src/google/protobuf/compiler/cpp/cpp_options.h
+++ b/src/google/protobuf/compiler/cpp/cpp_options.h
@@ -44,11 +44,16 @@ namespace cpp {
 // Generator options (see generator.cc for a description of each):
 struct Options {
   Options()
-      : safe_boundary_check(false), proto_h(false), annotate_headers(false) {}
+      : safe_boundary_check(false),
+        proto_h(false),
+        annotate_headers(false),
+        enforce_lite(false) {}
+
   string dllexport_decl;
   bool safe_boundary_check;
   bool proto_h;
   bool annotate_headers;
+  bool enforce_lite;
   string annotation_pragma_name;
   string annotation_guard_name;
 };
diff --git a/src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc
index d1efbfe6..34a41d82 100644
--- a/src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_plugin_unittest.cc
@@ -44,9 +44,10 @@
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/printer.h>
 
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/testing/file.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
index 9f929d37..650f0381 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.cc
@@ -100,10 +100,9 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
 
 // ===================================================================
 
-PrimitiveFieldGenerator::
-PrimitiveFieldGenerator(const FieldDescriptor* descriptor,
-                        const Options& options)
-  : descriptor_(descriptor) {
+PrimitiveFieldGenerator::PrimitiveFieldGenerator(
+    const FieldDescriptor* descriptor, const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetPrimitiveVariables(descriptor, &variables_, options);
 }
 
@@ -117,8 +116,8 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void PrimitiveFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$ $name$() const$deprecation$;\n"
-    "void set_$name$($type$ value)$deprecation$;\n");
+    "$deprecated_attr$$type$ $name$() const;\n"
+    "$deprecated_attr$void set_$name$($type$ value);\n");
 }
 
 void PrimitiveFieldGenerator::
@@ -256,10 +255,9 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
 
 // ===================================================================
 
-RepeatedPrimitiveFieldGenerator::
-RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor,
-                                const Options& options)
-  : descriptor_(descriptor) {
+RepeatedPrimitiveFieldGenerator::RepeatedPrimitiveFieldGenerator(
+    const FieldDescriptor* descriptor, const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetPrimitiveVariables(descriptor, &variables_, options);
 
   if (descriptor->is_packed()) {
@@ -277,7 +275,8 @@ void RepeatedPrimitiveFieldGenerator::
 GeneratePrivateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "::google::protobuf::RepeatedField< $type$ > $name$_;\n");
-  if (descriptor_->is_packed() && HasGeneratedMethods(descriptor_->file())) {
+  if (descriptor_->is_packed() &&
+      HasGeneratedMethods(descriptor_->file(), options_)) {
     printer->Print(variables_,
       "mutable int _$name$_cached_byte_size_;\n");
   }
@@ -286,14 +285,14 @@ GeneratePrivateMembers(io::Printer* printer) const {
 void RepeatedPrimitiveFieldGenerator::
 GenerateAccessorDeclarations(io::Printer* printer) const {
   printer->Print(variables_,
-    "$type$ $name$(int index) const$deprecation$;\n"
-    "void set_$name$(int index, $type$ value)$deprecation$;\n"
-    "void add_$name$($type$ value)$deprecation$;\n");
+    "$deprecated_attr$$type$ $name$(int index) const;\n"
+    "$deprecated_attr$void set_$name$(int index, $type$ value);\n"
+    "$deprecated_attr$void add_$name$($type$ value);\n");
   printer->Print(variables_,
-    "const ::google::protobuf::RepeatedField< $type$ >&\n"
-    "    $name$() const$deprecation$;\n"
-    "::google::protobuf::RepeatedField< $type$ >*\n"
-    "    mutable_$name$()$deprecation$;\n");
+    "$deprecated_attr$const ::google::protobuf::RepeatedField< $type$ >&\n"
+    "    $name$() const;\n"
+    "$deprecated_attr$::google::protobuf::RepeatedField< $type$ >*\n"
+    "    mutable_$name$();\n");
 }
 
 void RepeatedPrimitiveFieldGenerator::
diff --git a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
index fcd7d684..655ebde4 100644
--- a/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_primitive_field.h
@@ -46,8 +46,8 @@ namespace cpp {
 
 class PrimitiveFieldGenerator : public FieldGenerator {
  public:
-  explicit PrimitiveFieldGenerator(const FieldDescriptor* descriptor,
-                                   const Options& options);
+  PrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                          const Options& options);
   ~PrimitiveFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -74,8 +74,8 @@ class PrimitiveFieldGenerator : public FieldGenerator {
 
 class PrimitiveOneofFieldGenerator : public PrimitiveFieldGenerator {
  public:
-  explicit PrimitiveOneofFieldGenerator(const FieldDescriptor* descriptor,
-                                        const Options& options);
+  PrimitiveOneofFieldGenerator(const FieldDescriptor* descriptor,
+                               const Options& options);
   ~PrimitiveOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -92,8 +92,8 @@ class PrimitiveOneofFieldGenerator : public PrimitiveFieldGenerator {
 
 class RepeatedPrimitiveFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor,
-                                           const Options& options);
+  RepeatedPrimitiveFieldGenerator(const FieldDescriptor* descriptor,
+                                  const Options& options);
   ~RepeatedPrimitiveFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.cc b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
index 6b0821a6..1d743457 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.cc
@@ -76,10 +76,9 @@ void SetStringVariables(const FieldDescriptor* descriptor,
 
 // ===================================================================
 
-StringFieldGenerator::
-StringFieldGenerator(const FieldDescriptor* descriptor,
-                     const Options& options)
-  : descriptor_(descriptor) {
+StringFieldGenerator::StringFieldGenerator(const FieldDescriptor* descriptor,
+                                           const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetStringVariables(descriptor, &variables_, options);
 }
 
@@ -140,19 +139,19 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   }
 
   printer->Print(variables_,
-    "const ::std::string& $name$() const$deprecation$;\n"
-    "void set_$name$(const ::std::string& value)$deprecation$;\n"
-    "void set_$name$(const char* value)$deprecation$;\n"
-    "void set_$name$(const $pointer_type$* value, size_t size)"
-                 "$deprecation$;\n"
-    "::std::string* mutable_$name$()$deprecation$;\n"
-    "::std::string* $release_name$()$deprecation$;\n"
-    "void set_allocated_$name$(::std::string* $name$)$deprecation$;\n");
+    "$deprecated_attr$const ::std::string& $name$() const;\n"
+    "$deprecated_attr$void set_$name$(const ::std::string& value);\n"
+    "$deprecated_attr$void set_$name$(const char* value);\n"
+    "$deprecated_attr$void set_$name$(const $pointer_type$* value, size_t size)"
+                 ";\n"
+    "$deprecated_attr$::std::string* mutable_$name$();\n"
+    "$deprecated_attr$::std::string* $release_name$();\n"
+    "$deprecated_attr$void set_allocated_$name$(::std::string* $name$);\n");
   if (SupportsArenas(descriptor_)) {
     printer->Print(variables_,
-      "::std::string* unsafe_arena_release_$name$()$deprecation$;\n"
-      "void unsafe_arena_set_allocated_$name$(\n"
-      "    ::std::string* $name$)$deprecation$;\n");
+      "$deprecated_attr$::std::string* unsafe_arena_release_$name$();\n"
+      "$deprecated_attr$void unsafe_arena_set_allocated_$name$(\n"
+      "    ::std::string* $name$);\n");
   }
 
 
@@ -199,10 +198,12 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  return $name$_.Mutable($default_variable$, GetArenaNoVirtual());\n"
       "}\n"
       "$inline$ ::std::string* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  return $name$_.Release($default_variable$, GetArenaNoVirtual());\n"
       "}\n"
       "$inline$ ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_release:$full_name$)\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  $clear_hasbit$\n"
       "  return $name$_.UnsafeArenaRelease($default_variable$,\n"
@@ -228,7 +229,8 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  }\n"
       "  $name$_.UnsafeArenaSetAllocated($default_variable$,\n"
       "      $name$, GetArenaNoVirtual());\n"
-      "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:"
+      "$full_name$)\n"
       "}\n");
   } else {
     // No-arena case.
@@ -261,6 +263,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  return $name$_.MutableNoArena($default_variable$);\n"
       "}\n"
       "$inline$ ::std::string* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  $clear_hasbit$\n"
       "  return $name$_.ReleaseNoArena($default_variable$);\n"
       "}\n"
@@ -369,7 +372,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
 
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, true, variables_,
+        descriptor_, options_, true, variables_,
         "this->$name$().data(), this->$name$().length(),\n", printer);
   }
 }
@@ -378,7 +381,7 @@ void StringFieldGenerator::
 GenerateSerializeWithCachedSizes(io::Printer* printer) const {
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, false, variables_,
+        descriptor_, options_, false, variables_,
         "this->$name$().data(), this->$name$().length(),\n", printer);
   }
   printer->Print(variables_,
@@ -390,7 +393,7 @@ void StringFieldGenerator::
 GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const {
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, false, variables_,
+        descriptor_, options_, false, variables_,
         "this->$name$().data(), this->$name$().length(),\n", printer);
   }
   printer->Print(variables_,
@@ -477,6 +480,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  // @@protoc_insertion_point(field_mutable:$full_name$)\n"
       "}\n"
       "$inline$ ::std::string* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    return $oneof_prefix$$name$_.Release($default_variable$,\n"
@@ -486,6 +490,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  }\n"
       "}\n"
       "$inline$ ::std::string* $classname$::unsafe_arena_release_$name$() {\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_release:$full_name$)\n"
       "  GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
@@ -519,7 +524,8 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "    $oneof_prefix$$name$_.UnsafeArenaSetAllocated($default_variable$, "
       "$name$, GetArenaNoVirtual());\n"
       "  }\n"
-      "  // @@protoc_insertion_point(field_set_allocated:$full_name$)\n"
+      "  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:"
+      "$full_name$)\n"
       "}\n");
   } else {
     // No-arena case.
@@ -572,6 +578,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
       "  return $oneof_prefix$$name$_.MutableNoArena($default_variable$);\n"
       "}\n"
       "$inline$ ::std::string* $classname$::$release_name$() {\n"
+      "  // @@protoc_insertion_point(field_release:$full_name$)\n"
       "  if (has_$name$()) {\n"
       "    clear_has_$oneof_name$();\n"
       "    return $oneof_prefix$$name$_.ReleaseNoArena($default_variable$);\n"
@@ -658,7 +665,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
 
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, true, variables_,
+        descriptor_, options_, true, variables_,
         "this->$name$().data(), this->$name$().length(),\n", printer);
   }
 }
@@ -666,10 +673,9 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
 
 // ===================================================================
 
-RepeatedStringFieldGenerator::
-RepeatedStringFieldGenerator(const FieldDescriptor* descriptor,
-                             const Options& options)
-    : descriptor_(descriptor) {
+RepeatedStringFieldGenerator::RepeatedStringFieldGenerator(
+    const FieldDescriptor* descriptor, const Options& options)
+    : FieldGenerator(options), descriptor_(descriptor) {
   SetStringVariables(descriptor, &variables_, options);
 }
 
@@ -696,24 +702,24 @@ GenerateAccessorDeclarations(io::Printer* printer) const {
   }
 
   printer->Print(variables_,
-    "const ::std::string& $name$(int index) const$deprecation$;\n"
-    "::std::string* mutable_$name$(int index)$deprecation$;\n"
-    "void set_$name$(int index, const ::std::string& value)$deprecation$;\n"
-    "void set_$name$(int index, const char* value)$deprecation$;\n"
+    "$deprecated_attr$const ::std::string& $name$(int index) const;\n"
+    "$deprecated_attr$::std::string* mutable_$name$(int index);\n"
+    "$deprecated_attr$void set_$name$(int index, const ::std::string& value);\n"
+    "$deprecated_attr$void set_$name$(int index, const char* value);\n"
     ""
-    "void set_$name$(int index, const $pointer_type$* value, size_t size)"
-                 "$deprecation$;\n"
-    "::std::string* add_$name$()$deprecation$;\n"
-    "void add_$name$(const ::std::string& value)$deprecation$;\n"
-    "void add_$name$(const char* value)$deprecation$;\n"
-    "void add_$name$(const $pointer_type$* value, size_t size)"
-                 "$deprecation$;\n");
+    "$deprecated_attr$void set_$name$("
+                 "int index, const $pointer_type$* value, size_t size);\n"
+    "$deprecated_attr$::std::string* add_$name$();\n"
+    "$deprecated_attr$void add_$name$(const ::std::string& value);\n"
+    "$deprecated_attr$void add_$name$(const char* value);\n"
+    "$deprecated_attr$void add_$name$(const $pointer_type$* value, size_t size)"
+                 ";\n");
 
   printer->Print(variables_,
-    "const ::google::protobuf::RepeatedPtrField< ::std::string>& $name$() const"
-                 "$deprecation$;\n"
-    "::google::protobuf::RepeatedPtrField< ::std::string>* mutable_$name$()"
-                 "$deprecation$;\n");
+    "$deprecated_attr$const ::google::protobuf::RepeatedPtrField< ::std::string>& $name$() "
+                 "const;\n"
+    "$deprecated_attr$::google::protobuf::RepeatedPtrField< ::std::string>* mutable_$name$()"
+                 ";\n");
 
   if (unknown_ctype) {
     printer->Outdent();
@@ -752,6 +758,7 @@ GenerateInlineAccessorDefinitions(io::Printer* printer,
     "  // @@protoc_insertion_point(field_set_pointer:$full_name$)\n"
     "}\n"
     "$inline$ ::std::string* $classname$::add_$name$() {\n"
+    "  // @@protoc_insertion_point(field_add_mutable:$full_name$)\n"
     "  return $name$_.Add();\n"
     "}\n"
     "$inline$ void $classname$::add_$name$(const ::std::string& value) {\n"
@@ -807,7 +814,7 @@ GenerateMergeFromCodedStream(io::Printer* printer) const {
     "      input, this->add_$name$()));\n");
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, true, variables_,
+        descriptor_, options_, true, variables_,
         "this->$name$(this->$name$_size() - 1).data(),\n"
         "this->$name$(this->$name$_size() - 1).length(),\n",
         printer);
@@ -821,7 +828,7 @@ GenerateSerializeWithCachedSizes(io::Printer* printer) const {
   printer->Indent();
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, false, variables_,
+        descriptor_, options_, false, variables_,
         "this->$name$(i).data(), this->$name$(i).length(),\n", printer);
   }
   printer->Outdent();
@@ -838,7 +845,7 @@ GenerateSerializeWithCachedSizesToArray(io::Printer* printer) const {
   printer->Indent();
   if (descriptor_->type() == FieldDescriptor::TYPE_STRING) {
     GenerateUtf8CheckCodeForString(
-        descriptor_, false, variables_,
+        descriptor_, options_, false, variables_,
         "this->$name$(i).data(), this->$name$(i).length(),\n", printer);
   }
   printer->Outdent();
diff --git a/src/google/protobuf/compiler/cpp/cpp_string_field.h b/src/google/protobuf/compiler/cpp/cpp_string_field.h
index 616e2067..cb4e8772 100644
--- a/src/google/protobuf/compiler/cpp/cpp_string_field.h
+++ b/src/google/protobuf/compiler/cpp/cpp_string_field.h
@@ -46,8 +46,8 @@ namespace cpp {
 
 class StringFieldGenerator : public FieldGenerator {
  public:
-  explicit StringFieldGenerator(const FieldDescriptor* descriptor,
-                                const Options& options);
+  StringFieldGenerator(const FieldDescriptor* descriptor,
+                       const Options& options);
   ~StringFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -79,8 +79,8 @@ class StringFieldGenerator : public FieldGenerator {
 
 class StringOneofFieldGenerator : public StringFieldGenerator {
  public:
-  explicit StringOneofFieldGenerator(const FieldDescriptor* descriptor,
-                                     const Options& options);
+  StringOneofFieldGenerator(const FieldDescriptor* descriptor,
+                            const Options& options);
   ~StringOneofFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
@@ -99,8 +99,8 @@ class StringOneofFieldGenerator : public StringFieldGenerator {
 
 class RepeatedStringFieldGenerator : public FieldGenerator {
  public:
-  explicit RepeatedStringFieldGenerator(const FieldDescriptor* descriptor,
-                                        const Options& options);
+  RepeatedStringFieldGenerator(const FieldDescriptor* descriptor,
+                               const Options& options);
   ~RepeatedStringFieldGenerator();
 
   // implements FieldGenerator ---------------------------------------
diff --git a/src/google/protobuf/compiler/cpp/cpp_unittest.cc b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
index 148da883..5d82946d 100644
--- a/src/google/protobuf/compiler/cpp/cpp_unittest.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_unittest.cc
@@ -1252,7 +1252,7 @@ class GeneratedServiceTest : public testing::Test {
       foo_(descriptor_->FindMethodByName("Foo")),
       bar_(descriptor_->FindMethodByName("Bar")),
       stub_(&mock_channel_),
-      done_(google::protobuf::internal::NewPermanentCallback(&DoNothing)) {}
+      done_(::google::protobuf::internal::NewPermanentCallback(&DoNothing)) {}
 
   virtual void SetUp() {
     ASSERT_TRUE(foo_ != NULL);
diff --git a/src/google/protobuf/compiler/cpp/metadata_test.cc b/src/google/protobuf/compiler/cpp/metadata_test.cc
index 61dc283a..edd30780 100644
--- a/src/google/protobuf/compiler/cpp/metadata_test.cc
+++ b/src/google/protobuf/compiler/cpp/metadata_test.cc
@@ -41,9 +41,10 @@
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.pb.h>
 
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/testing/file.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/compiler/csharp/csharp_enum.cc b/src/google/protobuf/compiler/csharp/csharp_enum.cc
index 9616f172..bdfcc2be 100644
--- a/src/google/protobuf/compiler/csharp/csharp_enum.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_enum.cc
@@ -41,6 +41,7 @@
 #include <google/protobuf/compiler/csharp/csharp_doc_comment.h>
 #include <google/protobuf/compiler/csharp/csharp_enum.h>
 #include <google/protobuf/compiler/csharp/csharp_helpers.h>
+#include <google/protobuf/compiler/csharp/csharp_options.h>
 
 using google::protobuf::internal::scoped_ptr;
 
@@ -64,11 +65,24 @@ void EnumGenerator::Generate(io::Printer* printer) {
                  "access_level", class_access_level(),
                  "name", descriptor_->name());
   printer->Indent();
+  std::set<string> used_names;
   for (int i = 0; i < descriptor_->value_count(); i++) {
       WriteEnumValueDocComment(printer, descriptor_->value(i));
-      printer->Print("$name$ = $number$,\n",
-                   "name", descriptor_->value(i)->name(),
-                   "number", SimpleItoa(descriptor_->value(i)->number()));
+      string original_name = descriptor_->value(i)->name();
+      string name = options()->legacy_enum_values
+          ? descriptor_->value(i)->name()
+          : GetEnumValueName(descriptor_->name(), descriptor_->value(i)->name());
+      // Make sure we don't get any duplicate names due to prefix removal.
+      while (!used_names.insert(name).second) {
+        // It's possible we'll end up giving this warning multiple times, but that's better than not at all.
+        GOOGLE_LOG(WARNING) << "Duplicate enum value " << name << " (originally " << original_name
+          << ") in " << descriptor_->name() << "; adding underscore to distinguish";
+        name += "_";
+      }
+      printer->Print("[pbr::OriginalName(\"$original_name$\")] $name$ = $number$,\n",
+         "original_name", original_name,
+         "name", name,
+         "number", SimpleItoa(descriptor_->value(i)->number()));         
   }
   printer->Outdent();
   printer->Print("}\n");
diff --git a/src/google/protobuf/compiler/csharp/csharp_field_base.cc b/src/google/protobuf/compiler/csharp/csharp_field_base.cc
index 3b88954c..e3c34040 100644
--- a/src/google/protobuf/compiler/csharp/csharp_field_base.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_field_base.cc
@@ -306,7 +306,9 @@ std::string FieldGeneratorBase::default_value() {
 std::string FieldGeneratorBase::default_value(const FieldDescriptor* descriptor) {
   switch (descriptor->type()) {
     case FieldDescriptor::TYPE_ENUM:
-      return type_name() + "." + descriptor->default_value_enum()->name();
+      // All proto3 enums have a default value of 0, and there's an implicit conversion from the constant 0 to
+      // any C# enum. This means we don't need to work out what we actually mapped the enum value name to.
+     return "0";
     case FieldDescriptor::TYPE_MESSAGE:
     case FieldDescriptor::TYPE_GROUP:
       if (IsWrapperType(descriptor)) {
diff --git a/src/google/protobuf/compiler/csharp/csharp_generator.cc b/src/google/protobuf/compiler/csharp/csharp_generator.cc
index c13ed65b..d74e8c88 100644
--- a/src/google/protobuf/compiler/csharp/csharp_generator.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_generator.cc
@@ -83,6 +83,9 @@ bool Generator::Generate(
       cli_options.base_namespace_specified = true;
     } else if (options[i].first == "internal_access") {
       cli_options.internal_access = true;
+    } else if (options[i].first == "legacy_enum_values") {
+      // TODO: Remove this before final release
+      cli_options.legacy_enum_values = true;
     } else {
       *error = "Unknown generator option: " + options[i].first;
       return false;
diff --git a/src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc b/src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc
index 7ef7df42..5755fee0 100644
--- a/src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_generator_unittest.cc
@@ -30,8 +30,8 @@
 
 #include <memory>
 
-#include <google/protobuf/compiler/ruby/ruby_generator.h>
 #include <google/protobuf/compiler/command_line_interface.h>
+#include <google/protobuf/compiler/csharp/csharp_helpers.h>
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/printer.h>
 
@@ -45,7 +45,23 @@ namespace compiler {
 namespace csharp {
 namespace {
 
-// TODO(jtattermusch): add some tests.
+TEST(CSharpEnumValue, PascalCasedPrefixStripping) {
+  EXPECT_EQ("Bar", GetEnumValueName("Foo", "BAR"));
+  EXPECT_EQ("BarBaz", GetEnumValueName("Foo", "BAR_BAZ"));
+  EXPECT_EQ("Bar", GetEnumValueName("Foo", "FOO_BAR"));
+  EXPECT_EQ("Bar", GetEnumValueName("Foo", "FOO__BAR"));
+  EXPECT_EQ("BarBaz", GetEnumValueName("Foo", "FOO_BAR_BAZ"));
+  EXPECT_EQ("BarBaz", GetEnumValueName("Foo", "Foo_BarBaz"));
+  EXPECT_EQ("Bar", GetEnumValueName("FO_O", "FOO_BAR"));
+  EXPECT_EQ("Bar", GetEnumValueName("FOO", "F_O_O_BAR"));
+  EXPECT_EQ("Bar", GetEnumValueName("Foo", "BAR"));
+  EXPECT_EQ("BarBaz", GetEnumValueName("Foo", "BAR_BAZ"));
+  EXPECT_EQ("Foo", GetEnumValueName("Foo", "FOO"));
+  EXPECT_EQ("Foo", GetEnumValueName("Foo", "FOO___"));
+  // Identifiers can't start with digits
+  EXPECT_EQ("_2Bar", GetEnumValueName("Foo", "FOO_2_BAR"));
+  EXPECT_EQ("_2", GetEnumValueName("Foo", "FOO___2"));
+}
 
 }  // namespace
 }  // namespace csharp
diff --git a/src/google/protobuf/compiler/csharp/csharp_helpers.cc b/src/google/protobuf/compiler/csharp/csharp_helpers.cc
index 41265f9a..6c154c5a 100644
--- a/src/google/protobuf/compiler/csharp/csharp_helpers.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_helpers.cc
@@ -178,6 +178,104 @@ std::string UnderscoresToPascalCase(const std::string& input) {
   return UnderscoresToCamelCase(input, true);
 }
 
+// Convert a string which is expected to be SHOUTY_CASE (but may not be *precisely* shouty)
+// into a PascalCase string. Precise rules implemented:
+
+// Previous input character      Current character         Case
+// Any                           Non-alphanumeric          Skipped
+// None - first char of input    Alphanumeric              Upper
+// Non-letter (e.g. _ or 1)      Alphanumeric              Upper
+// Numeric                       Alphanumeric              Upper
+// Lower letter                  Alphanumeric              Same as current
+// Upper letter                  Alphanumeric              Lower
+std::string ShoutyToPascalCase(const std::string& input) {
+  string result;
+  // Simple way of implementing "always start with upper"
+  char previous = '_';
+  for (int i = 0; i < input.size(); i++) {
+    char current = input[i];
+    if (!ascii_isalnum(current)) {
+      previous = current;
+      continue;      
+    }
+    if (!ascii_isalnum(previous)) {
+      result += ascii_toupper(current);
+    } else if (ascii_isdigit(previous)) {
+      result += ascii_toupper(current);
+    } else if (ascii_islower(previous)) {
+      result += current;
+    } else {
+      result += ascii_tolower(current);
+    }
+    previous = current;
+  }
+  return result;
+}
+
+// Attempt to remove a prefix from a value, ignoring casing and skipping underscores.
+// (foo, foo_bar) => bar - underscore after prefix is skipped
+// (FOO, foo_bar) => bar - casing is ignored
+// (foo_bar, foobarbaz) => baz - underscore in prefix is ignored
+// (foobar, foo_barbaz) => baz - underscore in value is ignored
+// (foo, bar) => bar - prefix isn't matched; return original value
+std::string TryRemovePrefix(const std::string& prefix, const std::string& value) {
+  // First normalize to a lower-case no-underscores prefix to match against
+  std::string prefix_to_match = "";
+  for (size_t i = 0; i < prefix.size(); i++) {
+    if (prefix[i] != '_') {
+      prefix_to_match += ascii_tolower(prefix[i]);
+    }
+  }
+  
+  // This keeps track of how much of value we've consumed
+  size_t prefix_index, value_index;
+  for (prefix_index = 0, value_index = 0;
+      prefix_index < prefix_to_match.size() && value_index < value.size();
+      value_index++) {
+    // Skip over underscores in the value
+    if (value[value_index] == '_') {
+      continue;
+    }
+    if (ascii_tolower(value[value_index]) != prefix_to_match[prefix_index++]) {
+      // Failed to match the prefix - bail out early.
+      return value;
+    }
+  }
+
+  // If we didn't finish looking through the prefix, we can't strip it.
+  if (prefix_index < prefix_to_match.size()) {
+    return value;
+  }
+
+  // Step over any underscores after the prefix
+  while (value_index < value.size() && value[value_index] == '_') {
+    value_index++;
+  }
+
+  // If there's nothing left (e.g. it was a prefix with only underscores afterwards), don't strip.
+  if (value_index == value.size()) {
+    return value;
+  }
+
+  return value.substr(value_index);
+}
+
+// Format the enum value name in a pleasant way for C#:
+// - Strip the enum name as a prefix if possible
+// - Convert to PascalCase.
+// For example, an enum called Color with a value of COLOR_BLUE should
+// result in an enum value in C# called just Blue
+std::string GetEnumValueName(const std::string& enum_name, const std::string& enum_value_name) {
+  std::string stripped = TryRemovePrefix(enum_name, enum_value_name);
+  std::string result = ShoutyToPascalCase(stripped);
+  // Just in case we have an enum name of FOO and a value of FOO_2... make sure the returned
+  // string is a valid identifier.
+  if (ascii_isdigit(result[0])) {
+    result = "_" + result;
+  }
+  return result;
+}
+
 std::string ToCSharpName(const std::string& name, const FileDescriptor* file) {
   std::string result = GetFileNamespace(file);
   if (result != "") {
diff --git a/src/google/protobuf/compiler/csharp/csharp_helpers.h b/src/google/protobuf/compiler/csharp/csharp_helpers.h
index eaf85014..1563ca7e 100644
--- a/src/google/protobuf/compiler/csharp/csharp_helpers.h
+++ b/src/google/protobuf/compiler/csharp/csharp_helpers.h
@@ -36,6 +36,7 @@
 #define GOOGLE_PROTOBUF_COMPILER_CSHARP_HELPERS_H__
 
 #include <string>
+#include <google/protobuf/stubs/port.h>
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/descriptor.h>
 #include <google/protobuf/compiler/code_generator.h>
@@ -93,6 +94,10 @@ inline std::string UnderscoresToCamelCase(const std::string& input, bool cap_nex
 
 std::string UnderscoresToPascalCase(const std::string& input);
 
+// Note that we wouldn't normally want to export this (we're not expecting
+// it to be used outside libprotoc itself) but this exposes it for testing.
+std::string LIBPROTOBUF_EXPORT GetEnumValueName(const std::string& enum_name, const std::string& enum_value_name);
+
 // TODO(jtattermusch): perhaps we could move this to strutil
 std::string StringToBase64(const std::string& input);
 
diff --git a/src/google/protobuf/compiler/csharp/csharp_options.h b/src/google/protobuf/compiler/csharp/csharp_options.h
index 426fb3b5..4079bf7f 100644
--- a/src/google/protobuf/compiler/csharp/csharp_options.h
+++ b/src/google/protobuf/compiler/csharp/csharp_options.h
@@ -45,7 +45,8 @@ struct Options {
       file_extension(".cs"),
       base_namespace(""),
       base_namespace_specified(false),
-      internal_access(false) {
+      internal_access(false),
+      legacy_enum_values(false) {
   }
   // Extension of the generated file. Defaults to ".cs"
   string file_extension;
@@ -68,6 +69,12 @@ struct Options {
   // Whether the generated classes should have accessibility level of "internal".
   // Defaults to false that generates "public" classes.
   bool internal_access;
+  // By default, C# codegen now uses PascalCased enum values names, after
+  // removing the enum type name as a prefix (if it *is* a prefix of the value).
+  // Setting this option reverts to the previous behavior of just copying the
+  // value name specified in the .proto file, allowing gradual migration.
+  // This option will be removed before final release.
+  bool legacy_enum_values;
 };
 
 }  // namespace csharp
diff --git a/src/google/protobuf/compiler/importer_unittest.cc b/src/google/protobuf/compiler/importer_unittest.cc
index be19aa2e..1b6e9700 100644
--- a/src/google/protobuf/compiler/importer_unittest.cc
+++ b/src/google/protobuf/compiler/importer_unittest.cc
@@ -32,25 +32,26 @@
 //  Based on original Protocol Buffers design by
 //  Sanjay Ghemawat, Jeff Dean, and others.
 
+#include <google/protobuf/compiler/importer.h>
+
 #include <google/protobuf/stubs/hash.h>
 #include <memory>
 #ifndef _SHARED_PTR_H
 #include <google/protobuf/stubs/shared_ptr.h>
 #endif
 
-#include <google/protobuf/compiler/importer.h>
-#include <google/protobuf/descriptor.h>
-#include <google/protobuf/testing/file.h>
-#include <google/protobuf/io/zero_copy_stream_impl.h>
-
-#include <google/protobuf/stubs/map_util.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/descriptor.h>
 #include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
+#include <google/protobuf/stubs/map_util.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/compiler/java/java_doc_comment.cc b/src/google/protobuf/compiler/java/java_doc_comment.cc
index 663f0c97..0b5caba4 100644
--- a/src/google/protobuf/compiler/java/java_doc_comment.cc
+++ b/src/google/protobuf/compiler/java/java_doc_comment.cc
@@ -120,9 +120,7 @@ static void WriteDocCommentBodyForLocation(
       lines.pop_back();
     }
 
-    printer->Print(
-        " *\n"
-        " * <pre>\n");
+    printer->Print(" * <pre>\n");
     for (int i = 0; i < lines.size(); i++) {
       // Most lines should start with a space.  Watch out for lines that start
       // with a /, since putting that right after the leading asterisk will
@@ -133,7 +131,9 @@ static void WriteDocCommentBodyForLocation(
         printer->Print(" *$line$\n", "line", lines[i]);
       }
     }
-    printer->Print(" * </pre>\n");
+    printer->Print(
+        " * </pre>\n"
+        " *\n");
   }
 }
 
@@ -163,12 +163,12 @@ static string FirstLineOf(const string& value) {
 }
 
 void WriteMessageDocComment(io::Printer* printer, const Descriptor* message) {
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, message);
   printer->Print(
-    "/**\n"
-    " * Protobuf type {@code $fullname$}\n",
+    " * Protobuf type {@code $fullname$}\n"
+    " */\n",
     "fullname", EscapeJavadoc(message->full_name()));
-  WriteDocCommentBody(printer, message);
-  printer->Print(" */\n");
 }
 
 void WriteFieldDocComment(io::Printer* printer, const FieldDescriptor* field) {
@@ -176,55 +176,55 @@ void WriteFieldDocComment(io::Printer* printer, const FieldDescriptor* field) {
   // etc., but in practice everyone already knows the difference between these
   // so it's redundant information.
 
-  // We use the field declaration as the first line of the comment, e.g.:
+  // We start the comment with the main body based on the comments from the
+  // .proto file (if present). We then end with the field declaration, e.g.:
   //   optional string foo = 5;
-  // This communicates a lot of information about the field in a small space.
   // If the field is a group, the debug string might end with {.
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, field);
   printer->Print(
-    "/**\n"
     " * <code>$def$</code>\n",
     "def", EscapeJavadoc(FirstLineOf(field->DebugString())));
-  WriteDocCommentBody(printer, field);
   printer->Print(" */\n");
 }
 
 void WriteEnumDocComment(io::Printer* printer, const EnumDescriptor* enum_) {
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, enum_);
   printer->Print(
-    "/**\n"
-    " * Protobuf enum {@code $fullname$}\n",
+    " * Protobuf enum {@code $fullname$}\n"
+    " */\n",
     "fullname", EscapeJavadoc(enum_->full_name()));
-  WriteDocCommentBody(printer, enum_);
-  printer->Print(" */\n");
 }
 
 void WriteEnumValueDocComment(io::Printer* printer,
                               const EnumValueDescriptor* value) {
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, value);
   printer->Print(
-    "/**\n"
-    " * <code>$def$</code>\n",
+    " * <code>$def$</code>\n"
+    " */\n",
     "def", EscapeJavadoc(FirstLineOf(value->DebugString())));
-  WriteDocCommentBody(printer, value);
-  printer->Print(" */\n");
 }
 
 void WriteServiceDocComment(io::Printer* printer,
                             const ServiceDescriptor* service) {
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, service);
   printer->Print(
-    "/**\n"
-    " * Protobuf service {@code $fullname$}\n",
+    " * Protobuf service {@code $fullname$}\n"
+    " */\n",
     "fullname", EscapeJavadoc(service->full_name()));
-  WriteDocCommentBody(printer, service);
-  printer->Print(" */\n");
 }
 
 void WriteMethodDocComment(io::Printer* printer,
                            const MethodDescriptor* method) {
+  printer->Print("/**\n");
+  WriteDocCommentBody(printer, method);
   printer->Print(
-    "/**\n"
-    " * <code>$def$</code>\n",
+    " * <code>$def$</code>\n"
+    " */\n",
     "def", EscapeJavadoc(FirstLineOf(method->DebugString())));
-  WriteDocCommentBody(printer, method);
-  printer->Print(" */\n");
 }
 
 }  // namespace java
diff --git a/src/google/protobuf/compiler/java/java_enum.cc b/src/google/protobuf/compiler/java/java_enum.cc
index 9eea873a..947b80e4 100644
--- a/src/google/protobuf/compiler/java/java_enum.cc
+++ b/src/google/protobuf/compiler/java/java_enum.cc
@@ -92,6 +92,16 @@ void EnumGenerator::Generate(io::Printer* printer) {
     "classname", descriptor_->name());
   printer->Indent();
 
+  bool ordinal_is_index = true;
+  string index_text = "ordinal()";
+  for (int i = 0; i < canonical_values_.size(); i++) {
+    if (canonical_values_[i]->index() != i) {
+      ordinal_is_index = false;
+      index_text = "index";
+      break;
+    }
+  }
+
   for (int i = 0; i < canonical_values_.size(); i++) {
     map<string, string> vars;
     vars["name"] = canonical_values_[i]->name();
@@ -101,12 +111,21 @@ void EnumGenerator::Generate(io::Printer* printer) {
     if (canonical_values_[i]->options().deprecated()) {
       printer->Print("@java.lang.Deprecated\n");
     }
-    printer->Print(vars,
-      "$name$($index$, $number$),\n");
+    if (ordinal_is_index) {
+      printer->Print(vars,
+        "$name$($number$),\n");
+    } else {
+      printer->Print(vars,
+        "$name$($index$, $number$),\n");
+    }
   }
 
   if (SupportUnknownEnumValue(descriptor_->file())) {
-    printer->Print("UNRECOGNIZED(-1, -1),\n");
+    if (ordinal_is_index) {
+      printer->Print("UNRECOGNIZED(-1),\n");
+    } else {
+      printer->Print("UNRECOGNIZED(-1, -1),\n");
+    }
   }
 
   printer->Print(
@@ -141,11 +160,19 @@ void EnumGenerator::Generate(io::Printer* printer) {
     "\n"
     "public final int getNumber() {\n");
   if (SupportUnknownEnumValue(descriptor_->file())) {
-    printer->Print(
-      "  if (index == -1) {\n"
-      "    throw new java.lang.IllegalArgumentException(\n"
-      "        \"Can't get the number of an unknown enum value.\");\n"
-      "  }\n");
+    if (ordinal_is_index) {
+      printer->Print(
+        "  if (this == UNRECOGNIZED) {\n"
+        "    throw new java.lang.IllegalArgumentException(\n"
+        "        \"Can't get the number of an unknown enum value.\");\n"
+        "  }\n");
+    } else {
+      printer->Print(
+        "  if (index == -1) {\n"
+        "    throw new java.lang.IllegalArgumentException(\n"
+        "        \"Can't get the number of an unknown enum value.\");\n"
+        "  }\n");
+    }
   }
   printer->Print(
     "  return value;\n"
@@ -200,14 +227,15 @@ void EnumGenerator::Generate(io::Printer* printer) {
     printer->Print(
       "public final com.google.protobuf.Descriptors.EnumValueDescriptor\n"
       "    getValueDescriptor() {\n"
-      "  return getDescriptor().getValues().get(index);\n"
+      "  return getDescriptor().getValues().get($index_text$);\n"
       "}\n"
       "public final com.google.protobuf.Descriptors.EnumDescriptor\n"
       "    getDescriptorForType() {\n"
       "  return getDescriptor();\n"
       "}\n"
       "public static final com.google.protobuf.Descriptors.EnumDescriptor\n"
-      "    getDescriptor() {\n");
+      "    getDescriptor() {\n",
+      "index_text", index_text);
 
     // TODO(kenton):  Cache statically?  Note that we can't access descriptors
     //   at module init time because it wouldn't work with descriptor.proto, but
@@ -313,16 +341,27 @@ void EnumGenerator::Generate(io::Printer* printer) {
       "}\n"
       "\n");
 
-    printer->Print("private final int index;\n");
+    if (!ordinal_is_index) {
+      printer->Print("private final int index;\n");
+    }
   }
 
   // -----------------------------------------------------------------
 
   printer->Print(
-    "private final int value;\n\n"
-    "private $classname$(int index, int value) {\n",
-    "classname", descriptor_->name());
-  if (HasDescriptorMethods(descriptor_, context_->EnforceLite())) {
+    "private final int value;\n\n");
+
+  if (ordinal_is_index) {
+    printer->Print(
+      "private $classname$(int value) {\n",
+      "classname", descriptor_->name());
+  } else {
+    printer->Print(
+      "private $classname$(int index, int value) {\n",
+      "classname", descriptor_->name());
+  }
+  if (HasDescriptorMethods(descriptor_, context_->EnforceLite()) &&
+      !ordinal_is_index) {
     printer->Print("  this.index = index;\n");
   }
   printer->Print(
diff --git a/src/google/protobuf/compiler/java/java_enum_field_lite.cc b/src/google/protobuf/compiler/java/java_enum_field_lite.cc
index 5b98637b..908d6db4 100644
--- a/src/google/protobuf/compiler/java/java_enum_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_enum_field_lite.cc
@@ -262,17 +262,15 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void ImmutableEnumFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   if (SupportFieldPresence(descriptor_->file())) {
     printer->Print(variables_,
-      "if (other.has$capitalized_name$()) {\n"
-      "  set$capitalized_name$(other.get$capitalized_name$());\n"
-      "}\n");
+      "$name$_ = visitor.visitInt(has$capitalized_name$(), $name$_,\n"
+      "    other.has$capitalized_name$(), other.$name$_);\n");
   } else if (SupportUnknownEnumValue(descriptor_->file())) {
     printer->Print(variables_,
-      "if (other.$name$_ != $default_number$) {\n"
-      "  set$capitalized_name$Value(other.get$capitalized_name$Value());\n"
-      "}\n");
+      "$name$_ = visitor.visitInt($name$_ != $default_number$, $name$_,"
+      "    other.$name$_ != $default_number$, other.$name$_);\n");
   } else {
     GOOGLE_LOG(FATAL) << "Can't reach here.";
   }
@@ -466,14 +464,10 @@ GenerateBuilderMembers(io::Printer* printer) const {
 }
 
 void ImmutableEnumOneofFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  if (SupportUnknownEnumValue(descriptor_->file())) {
-    printer->Print(variables_,
-      "set$capitalized_name$Value(other.get$capitalized_name$Value());\n");
-  } else {
-    printer->Print(variables_,
-      "set$capitalized_name$(other.get$capitalized_name$());\n");
-  }
+GenerateVisitCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "$oneof_name$_ = visitor.visitOneofInt(\n"
+    "   $has_oneof_case_message$, $oneof_name$_, other.$oneof_name$_);\n");
 }
 
 void ImmutableEnumOneofFieldLiteGenerator::
@@ -645,7 +639,8 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = newIntList($name$_);\n"
+    "    $name$_ =\n"
+    "        com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "  }\n"
     "}\n");
   WriteFieldDocComment(printer, descriptor_);
@@ -805,21 +800,9 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutableEnumFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  // The code below does two optimizations:
-  //   1. If the other list is empty, there's nothing to do. This ensures we
-  //      don't allocate a new array if we already have an immutable one.
-  //   2. If the other list is non-empty and our current list is empty, we can
-  //      reuse the other list which is guaranteed to be immutable.
-  printer->Print(variables_,
-    "if (!other.$name$_.isEmpty()) {\n"
-    "  if ($name$_.isEmpty()) {\n"
-    "    $name$_ = other.$name$_;\n"
-    "  } else {\n"
-    "    ensure$capitalized_name$IsMutable();\n"
-    "    $name$_.addAll(other.$name$_);\n"
-    "  }\n"
-    "}\n");
+GenerateVisitCode(io::Printer* printer) const {
+  printer->Print(variables_,
+    "$name$_= visitor.visitIntList($name$_, other.$name$_);\n");
 }
 
 void RepeatedImmutableEnumFieldLiteGenerator::
@@ -831,27 +814,23 @@ GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const {
 void RepeatedImmutableEnumFieldLiteGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   // Read and store the enum
+  printer->Print(variables_,
+    "if (!$is_mutable$) {\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
+    "}\n");
+
   if (SupportUnknownEnumValue(descriptor_->file())) {
     printer->Print(variables_,
-      "int rawValue = input.readEnum();\n"
-      "if (!$is_mutable$) {\n"
-      "  $name$_ = newIntList();\n"
-      "}\n"
-      "$name$_.addInt(rawValue);\n");
+      "$name$_.addInt(input.readEnum());\n");
   } else {
     printer->Print(variables_,
       "int rawValue = input.readEnum();\n"
       "$type$ value = $type$.forNumber(rawValue);\n"
-        "if (value == null) {\n");
-    if (PreserveUnknownFields(descriptor_->containing_type())) {
-      printer->Print(variables_,
-        "  super.mergeVarintField($number$, rawValue);\n");
-    }
-    printer->Print(variables_,
+      "if (value == null) {\n"
+      // We store the unknown value in unknown fields.
+      "  super.mergeVarintField($number$, rawValue);\n"
       "} else {\n"
-      "  if (!$is_mutable$) {\n"
-      "    $name$_ = newIntList();\n"
-      "  }\n"
       "  $name$_.addInt(rawValue);\n"
       "}\n");
   }
@@ -859,7 +838,11 @@ GenerateParsingCode(io::Printer* printer) const {
 
 void RepeatedImmutableEnumFieldLiteGenerator::
 GenerateParsingCodeFromPacked(io::Printer* printer) const {
-  // Wrap GenerateParsingCode's contents with a while loop.
+  printer->Print(variables_,
+    "if (!$is_mutable$) {\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
+    "}\n");
 
   printer->Print(variables_,
     "int length = input.readRawVarint32();\n"
@@ -867,7 +850,21 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
     "while(input.getBytesUntilLimit() > 0) {\n");
   printer->Indent();
 
-  GenerateParsingCode(printer);
+  // Read and store the enum
+  if (SupportUnknownEnumValue(descriptor_->file())) {
+    printer->Print(variables_,
+      "$name$_.addInt(input.readEnum());\n");
+  } else {
+    printer->Print(variables_,
+      "int rawValue = input.readEnum();\n"
+      "$type$ value = $type$.forNumber(rawValue);\n"
+      "if (value == null) {\n"
+      // We store the unknown value in unknown fields.
+      "  super.mergeVarintField($number$, rawValue);\n"
+      "} else {\n"
+      "  $name$_.addInt(rawValue);\n"
+      "}\n");
+  }
 
   printer->Outdent();
   printer->Print(variables_,
diff --git a/src/google/protobuf/compiler/java/java_enum_field_lite.h b/src/google/protobuf/compiler/java/java_enum_field_lite.h
index 2c41c3e4..9201b8d6 100644
--- a/src/google/protobuf/compiler/java/java_enum_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_enum_field_lite.h
@@ -67,7 +67,7 @@ class ImmutableEnumFieldLiteGenerator : public ImmutableFieldLiteGenerator {
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
@@ -101,7 +101,7 @@ class ImmutableEnumOneofFieldLiteGenerator
 
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
@@ -127,7 +127,7 @@ class RepeatedImmutableEnumFieldLiteGenerator
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingCodeFromPacked(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_field.h b/src/google/protobuf/compiler/java/java_field.h
index 0e24da24..4dd4f57f 100644
--- a/src/google/protobuf/compiler/java/java_field.h
+++ b/src/google/protobuf/compiler/java/java_field.h
@@ -105,7 +105,7 @@ class ImmutableFieldLiteGenerator {
   virtual void GenerateMembers(io::Printer* printer) const = 0;
   virtual void GenerateBuilderMembers(io::Printer* printer) const = 0;
   virtual void GenerateInitializationCode(io::Printer* printer) const = 0;
-  virtual void GenerateMergingCode(io::Printer* printer) const = 0;
+  virtual void GenerateVisitCode(io::Printer* printer) const = 0;
   virtual void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer)
       const = 0;
   virtual void GenerateParsingCode(io::Printer* printer) const = 0;
diff --git a/src/google/protobuf/compiler/java/java_lazy_message_field_lite.cc b/src/google/protobuf/compiler/java/java_lazy_message_field_lite.cc
index a648f1c2..62f39302 100644
--- a/src/google/protobuf/compiler/java/java_lazy_message_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_lazy_message_field_lite.cc
@@ -182,12 +182,11 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void ImmutableLazyMessageFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (other.has$capitalized_name$()) {\n"
-    "  $name$_.merge(other.$name$_);\n"
-    "  $set_has_field_bit_message$;\n"
-    "}\n");
+    "$name$_ = visitor.visitLazyMessage(\n"
+    "    has$capitalized_name$(), $name$_,\n"
+    "    other.has$capitalized_name$(), other.$name$_);\n");
 }
 
 void ImmutableLazyMessageFieldLiteGenerator::
@@ -362,14 +361,12 @@ GenerateBuilderMembers(io::Printer* printer) const {
 }
 
 void ImmutableLazyMessageOneofFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (!($has_oneof_case_message$)) {\n"
-    "  $oneof_name$_ = new $lazy_type$();\n"
-    "}\n"
-    "(($lazy_type$) $oneof_name$_).merge(\n"
-    "    ($lazy_type$) other.$oneof_name$_);\n"
-    "$set_oneof_case_message$;\n");
+    "$oneof_name$_ = visitor.visitOneofLazyMessage(\n"
+    "    $has_oneof_case_message$,\n"
+    "    ($lazy_type$) $oneof_name$_,\n"
+    "    ($lazy_type$) other.$oneof_name$_);\n");
 }
 
 void ImmutableLazyMessageOneofFieldLiteGenerator::
@@ -463,7 +460,8 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = newProtobufList($name$_);\n"
+    "    $name$_ =\n"
+    "        com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "   }\n"
     "}\n"
     "\n");
@@ -678,7 +676,8 @@ void RepeatedImmutableLazyMessageFieldLiteGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if (!$is_mutable$) {\n"
-    "  $name$_ = newProtobufList();\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "}\n"
     "$name$_.add(new com.google.protobuf.LazyFieldLite(\n"
     "    extensionRegistry, input.readBytes()));\n");
diff --git a/src/google/protobuf/compiler/java/java_lazy_message_field_lite.h b/src/google/protobuf/compiler/java/java_lazy_message_field_lite.h
index e85ec0f3..47ebeb49 100644
--- a/src/google/protobuf/compiler/java/java_lazy_message_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_lazy_message_field_lite.h
@@ -63,7 +63,7 @@ class ImmutableLazyMessageFieldLiteGenerator
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
@@ -82,7 +82,7 @@ class ImmutableLazyMessageOneofFieldLiteGenerator
 
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_map_field.cc b/src/google/protobuf/compiler/java/java_map_field.cc
index 17c3646f..2a551ca4 100644
--- a/src/google/protobuf/compiler/java/java_map_field.cc
+++ b/src/google/protobuf/compiler/java/java_map_field.cc
@@ -215,7 +215,7 @@ GenerateMembers(io::Printer* printer) const {
       "  if ($name$_ == null) {\n"
       "    return com.google.protobuf.MapField$lite$.emptyMapField(\n"
       "        $map_field_parameter$);\n"
-      " }\n"
+      "  }\n"
       "  return $name$_;\n"
       "}\n");
   if (GetJavaType(ValueField(descriptor_)) == JAVATYPE_ENUM) {
@@ -270,7 +270,7 @@ GenerateBuilderMembers(io::Printer* printer) const {
       "  if ($name$_ == null) {\n"
       "    return com.google.protobuf.MapField$lite$.emptyMapField(\n"
       "        $map_field_parameter$);\n"
-      " }\n"
+      "  }\n"
       "  return $name$_;\n"
       "}\n"
       "private com.google.protobuf.MapField$lite$<$type_parameters$>\n"
diff --git a/src/google/protobuf/compiler/java/java_map_field_lite.cc b/src/google/protobuf/compiler/java/java_map_field_lite.cc
index 6bdebb0d..b80d4139 100644
--- a/src/google/protobuf/compiler/java/java_map_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_map_field_lite.cc
@@ -374,10 +374,10 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void ImmutableMapFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(
       variables_,
-      "internalGetMutable$capitalized_name$().mergeFrom(\n"
+      "$name$_ = visitor.visitMap(internalGetMutable$capitalized_name$(),\n"
       "    other.internalGet$capitalized_name$());\n");
 }
 
diff --git a/src/google/protobuf/compiler/java/java_map_field_lite.h b/src/google/protobuf/compiler/java/java_map_field_lite.h
index a09cd536..555b5c5b 100644
--- a/src/google/protobuf/compiler/java/java_map_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_map_field_lite.h
@@ -52,7 +52,7 @@ class ImmutableMapFieldLiteGenerator : public ImmutableFieldLiteGenerator {
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_message.cc b/src/google/protobuf/compiler/java/java_message.cc
index dfd8ad08..4c474a48 100644
--- a/src/google/protobuf/compiler/java/java_message.cc
+++ b/src/google/protobuf/compiler/java/java_message.cc
@@ -89,7 +89,6 @@ MessageGenerator::MessageGenerator(const Descriptor* descriptor)
 MessageGenerator::~MessageGenerator() {}
 
 // ===================================================================
-// TODO(api): Move this class to a separate immutable_message.cc file.
 ImmutableMessageGenerator::ImmutableMessageGenerator(
     const Descriptor* descriptor, Context* context)
   : MessageGenerator(descriptor), context_(context),
@@ -1226,7 +1225,8 @@ GenerateParsingConstructor(io::Printer* printer) {
       "default: {\n"
       "  if (!input.skipField(tag)) {\n"
       "    done = true;\n"  // it's an endgroup tag
-      "  }\n"
+      "  }\n");
+    printer->Print(
       "  break;\n"
       "}\n");
   }
diff --git a/src/google/protobuf/compiler/java/java_message_field_lite.cc b/src/google/protobuf/compiler/java/java_message_field_lite.cc
index 049679df..14281816 100644
--- a/src/google/protobuf/compiler/java/java_message_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_message_field_lite.cc
@@ -286,11 +286,9 @@ void ImmutableMessageFieldLiteGenerator::
 GenerateInitializationCode(io::Printer* printer) const {}
 
 void ImmutableMessageFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "if (other.has$capitalized_name$()) {\n"
-    "  merge$capitalized_name$(other.get$capitalized_name$());\n"
-    "}\n");
+    "$name$_ = visitor.visitMessage($name$_, other.$name$_);\n");
 }
 
 void ImmutableMessageFieldLiteGenerator::
@@ -300,11 +298,18 @@ GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const {
 
 void ImmutableMessageFieldLiteGenerator::
 GenerateParsingCode(io::Printer* printer) const {
-  printer->Print(variables_,
-    "$type$.Builder subBuilder = null;\n"
-    "if ($is_field_present_message$) {\n"
-    "  subBuilder = $name$_.toBuilder();\n"
-    "}\n");
+  // TODO(dweis): Update this code to avoid the builder allocation and instead
+  // only allocate a submessage that isn't made immutable. Rely on the top
+  // message calling makeImmutable once done to actually traverse the tree and
+  // finalize state. This will avoid:
+  // - transitive builder allocations
+  // - the extra transitive iteration for streamed fields
+  // - reallocations for copying repeated fields
+  printer->Print(variables_,
+      "$type$.Builder subBuilder = null;\n"
+      "if ($is_field_present_message$) {\n"
+      "  subBuilder = $name$_.toBuilder();\n"
+      "}\n");
 
     if (GetType(descriptor_) == FieldDescriptor::TYPE_GROUP) {
       printer->Print(variables_,
@@ -504,9 +509,12 @@ GenerateBuilderMembers(io::Printer* printer) const {
 }
 
 void ImmutableMessageOneofFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "merge$capitalized_name$(other.get$capitalized_name$());\n");
+    "$oneof_name$_ = visitor.visitOneofMessage(\n"
+    "    $has_oneof_case_message$,\n"
+    "    $oneof_name$_,\n"
+    "    other.$oneof_name$_);\n");
 }
 
 void ImmutableMessageOneofFieldLiteGenerator::
@@ -633,7 +641,8 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = newProtobufList($name$_);\n"
+    "    $name$_ =\n"
+    "        com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "   }\n"
     "}\n"
     "\n");
@@ -851,21 +860,9 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutableMessageFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  // The code below does two optimizations (non-nested builder case):
-  //   1. If the other list is empty, there's nothing to do. This ensures we
-  //      don't allocate a new array if we already have an immutable one.
-  //   2. If the other list is non-empty and our current list is empty, we can
-  //      reuse the other list which is guaranteed to be immutable.
-  printer->Print(variables_,
-    "if (!other.$name$_.isEmpty()) {\n"
-    "  if ($name$_.isEmpty()) {\n"
-    "    $name$_ = other.$name$_;\n"
-    "  } else {\n"
-    "    ensure$capitalized_name$IsMutable();\n"
-    "    $name$_.addAll(other.$name$_);\n"
-    "  }\n"
-    "}\n");
+GenerateVisitCode(io::Printer* printer) const {
+  printer->Print(variables_,
+      "$name$_= visitor.visitList($name$_, other.$name$_);\n");
 }
 
 void RepeatedImmutableMessageFieldLiteGenerator::
@@ -878,7 +875,8 @@ void RepeatedImmutableMessageFieldLiteGenerator::
 GenerateParsingCode(io::Printer* printer) const {
   printer->Print(variables_,
     "if (!$is_mutable$) {\n"
-    "  $name$_ = newProtobufList();\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "}\n");
 
     if (GetType(descriptor_) == FieldDescriptor::TYPE_GROUP) {
diff --git a/src/google/protobuf/compiler/java/java_message_field_lite.h b/src/google/protobuf/compiler/java/java_message_field_lite.h
index ae26c06a..61321547 100644
--- a/src/google/protobuf/compiler/java/java_message_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_message_field_lite.h
@@ -67,7 +67,7 @@ class ImmutableMessageFieldLiteGenerator : public ImmutableFieldLiteGenerator {
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
@@ -101,7 +101,7 @@ class ImmutableMessageOneofFieldLiteGenerator
 
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
@@ -125,7 +125,7 @@ class RepeatedImmutableMessageFieldLiteGenerator
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_message_lite.cc b/src/google/protobuf/compiler/java/java_message_lite.cc
index 14cc908b..d4d2593a 100644
--- a/src/google/protobuf/compiler/java/java_message_lite.cc
+++ b/src/google/protobuf/compiler/java/java_message_lite.cc
@@ -199,7 +199,7 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
   printer->Indent();
 
 
-  GenerateParsingConstructor(printer);
+  GenerateConstructor(printer);
 
   // Nested types
   for (int i = 0; i < descriptor_->enum_type_count(); i++) {
@@ -322,10 +322,6 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
 
   GenerateMessageSerializationMethods(printer);
 
-  if (HasEqualsAndHashCode(descriptor_)) {
-    GenerateEqualsAndHashCode(printer);
-  }
-
   GenerateParseFromMethods(printer);
   GenerateBuilder(printer);
 
@@ -342,16 +338,8 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
     "    com.google.protobuf.GeneratedMessageLite.MethodToInvoke method,\n"
     "    Object arg0, Object arg1) {\n"
     "  switch (method) {\n"
-    "    case PARSE_PARTIAL_FROM: {\n"
-    "      return new $classname$("
-    "          (com.google.protobuf.CodedInputStream) arg0,\n"
-    "          (com.google.protobuf.ExtensionRegistryLite) arg1);\n"
-    "    }\n"
-    "    case NEW_INSTANCE: {\n"
-    "      return new $classname$(\n"
-    "          com.google.protobuf.Internal.EMPTY_CODED_INPUT_STREAM,\n"
-    "          com.google.protobuf.ExtensionRegistryLite\n"
-    "              .getEmptyRegistry());\n"
+    "    case NEW_MUTABLE_INSTANCE: {\n"
+    "      return new $classname$();\n"
     "    }\n",
     "classname", name_resolver_->GetImmutableClassName(descriptor_));
 
@@ -382,10 +370,18 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
 
   printer->Print(
     "}\n"
-    "case MERGE_FROM: {\n");
+    "case VISIT: {\n");
 
   printer->Indent();
-  GenerateDynamicMethodMergeFrom(printer);
+  GenerateDynamicMethodVisit(printer);
+  printer->Outdent();
+
+  printer->Print(
+    "}\n"
+    "case MERGE_FROM_STREAM: {\n");
+
+  printer->Indent();
+  GenerateDynamicMethodMergeFromStream(printer);
   printer->Outdent();
 
   printer->Print(
@@ -433,11 +429,8 @@ void ImmutableMessageLiteGenerator::Generate(io::Printer* printer) {
 
   printer->Print(
     "static {\n"
-    "  DEFAULT_INSTANCE = new $classname$(\n"
-    "      com.google.protobuf.Internal\n"
-    "          .EMPTY_CODED_INPUT_STREAM,\n"
-    "      com.google.protobuf.ExtensionRegistryLite\n"
-    "          .getEmptyRegistry());\n"
+    "  DEFAULT_INSTANCE = new $classname$();\n"
+    "  DEFAULT_INSTANCE.makeImmutable();\n"
     "}\n"
     "\n",
     "classname", descriptor_->name());
@@ -802,11 +795,13 @@ void ImmutableMessageLiteGenerator::GenerateDynamicMethodIsInitialized(
 
 void ImmutableMessageLiteGenerator::GenerateDynamicMethodMakeImmutable(
     io::Printer* printer) {
+
   // Output generation code for each field.
   for (int i = 0; i < descriptor_->field_count(); i++) {
     field_generators_.get(descriptor_->field(i))
         .GenerateDynamicMethodMakeImmutableCode(printer);
   }
+
   printer->Print(
     "return null;\n");
 }
@@ -821,19 +816,17 @@ void ImmutableMessageLiteGenerator::GenerateDynamicMethodNewBuilder(
 
 // ===================================================================
 
-void ImmutableMessageLiteGenerator::GenerateDynamicMethodMergeFrom(
+void ImmutableMessageLiteGenerator::GenerateDynamicMethodVisit(
     io::Printer* printer) {
   printer->Print(
-    // Optimization:  If other is the default instance, we know none of its
-    //   fields are set so we can skip the merge.
-    "if (arg0 == $classname$.getDefaultInstance()) return this;\n"
-    "$classname$ other = ($classname$) arg0;\n",
+    "Visitor visitor = (Visitor) arg0;\n"
+    "$classname$ other = ($classname$) arg1;\n",
     "classname", name_resolver_->GetImmutableClassName(descriptor_));
 
   for (int i = 0; i < descriptor_->field_count(); i++) {
     if (!descriptor_->field(i)->containing_oneof()) {
       field_generators_.get(
-          descriptor_->field(i)).GenerateMergingCode(printer);
+          descriptor_->field(i)).GenerateVisitCode(printer);
     }
   }
 
@@ -852,7 +845,7 @@ void ImmutableMessageLiteGenerator::GenerateDynamicMethodMergeFrom(
         "field_name",
         ToUpper(field->name()));
       printer->Indent();
-      field_generators_.get(field).GenerateMergingCode(printer);
+      field_generators_.get(field).GenerateVisitCode(printer);
       printer->Print(
           "break;\n");
       printer->Outdent();
@@ -861,254 +854,66 @@ void ImmutableMessageLiteGenerator::GenerateDynamicMethodMergeFrom(
     }
     printer->Print(
       "case $cap_oneof_name$_NOT_SET: {\n"
+      "  visitor.visitOneofNotSet($oneof_name$Case_ != 0);\n"
       "  break;\n"
       "}\n",
       "cap_oneof_name",
       ToUpper(context_->GetOneofGeneratorInfo(
-          descriptor_->oneof_decl(i))->name));
-    printer->Outdent();
-    printer->Print(
-      "}\n");
-  }
-
-  // if message type has extensions
-  if (descriptor_->extension_range_count() > 0) {
-    printer->Print(
-      "this.mergeExtensionFields(other);\n");
-  }
-
-  if (PreserveUnknownFields(descriptor_)) {
-    printer->Print(
-      "this.mergeUnknownFields(other.unknownFields);\n");
-  }
-
-  printer->Print(
-    "return this;\n");
-}
-
-// ===================================================================
-
-namespace {
-bool CheckHasBitsForEqualsAndHashCode(const FieldDescriptor* field) {
-  if (field->is_repeated()) {
-    return false;
-  }
-  if (SupportFieldPresence(field->file())) {
-    return true;
-  }
-  return GetJavaType(field) == JAVATYPE_MESSAGE &&
-      field->containing_oneof() == NULL;
-}
-}  // namespace
-
-void ImmutableMessageLiteGenerator::
-GenerateEqualsAndHashCode(io::Printer* printer) {
-  printer->Print(
-    "@java.lang.Override\n"
-    "public boolean equals(final java.lang.Object obj) {\n");
-  printer->Indent();
-  printer->Print(
-    "if (obj == this) {\n"
-    " return true;\n"
-    "}\n"
-    "if (!(obj instanceof $classname$)) {\n"
-    "  return super.equals(obj);\n"
-    "}\n"
-    "$classname$ other = ($classname$) obj;\n"
-    "\n",
-    "classname", name_resolver_->GetImmutableClassName(descriptor_));
-
-  printer->Print("boolean result = true;\n");
-  // Compare non-oneofs.
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = descriptor_->field(i);
-    if (field->containing_oneof() == NULL) {
-      const FieldGeneratorInfo* info = context_->GetFieldGeneratorInfo(field);
-      bool check_has_bits = CheckHasBitsForEqualsAndHashCode(field);
-      if (check_has_bits) {
-        printer->Print(
-          "result = result && (has$name$() == other.has$name$());\n"
-          "if (has$name$()) {\n",
-          "name", info->capitalized_name);
-        printer->Indent();
-      }
-      field_generators_.get(field).GenerateEqualsCode(printer);
-      if (check_has_bits) {
-        printer->Outdent();
-        printer->Print(
-          "}\n");
-      }
-    }
-  }
-
-  // Compare oneofs.
-  for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
-    printer->Print(
-      "result = result && get$oneof_capitalized_name$Case().equals(\n"
-      "    other.get$oneof_capitalized_name$Case());\n",
-      "oneof_capitalized_name",
-      context_->GetOneofGeneratorInfo(
-          descriptor_->oneof_decl(i))->capitalized_name);
-    printer->Print(
-      "if (!result) return false;\n"
-      "switch ($oneof_name$Case_) {\n",
+          descriptor_->oneof_decl(i))->name),
       "oneof_name",
       context_->GetOneofGeneratorInfo(
           descriptor_->oneof_decl(i))->name);
-    printer->Indent();
-    for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
-      const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
-      printer->Print(
-        "case $field_number$:\n",
-        "field_number",
-        SimpleItoa(field->number()));
-      printer->Indent();
-      field_generators_.get(field).GenerateEqualsCode(printer);
-      printer->Print("break;\n");
-      printer->Outdent();
-    }
-    printer->Print(
-      "case 0:\n"
-      "default:\n");
     printer->Outdent();
-    printer->Print("}\n");
-  }
-
-  if (PreserveUnknownFields(descriptor_)) {
-    // Always consider unknown fields for equality. This will sometimes return
-    // false for non-canonical ordering when running in LITE_RUNTIME but it's
-    // the best we can do.
     printer->Print(
-      "result = result && unknownFields.equals(other.unknownFields);\n");
+      "}\n");
   }
-  printer->Print(
-    "return result;\n");
-  printer->Outdent();
-  printer->Print(
-    "}\n"
-    "\n");
 
   printer->Print(
-    "@java.lang.Override\n"
-    "public int hashCode() {\n");
-  printer->Indent();
-  printer->Print(
-    "if (memoizedHashCode != 0) {\n");
+    "if (visitor == com.google.protobuf.GeneratedMessageLite.MergeFromVisitor\n"
+    "    .INSTANCE) {\n");
   printer->Indent();
-  printer->Print(
-    "return memoizedHashCode;\n");
-  printer->Outdent();
-  printer->Print(
-    "}\n"
-    "int hash = 41;\n");
-
-  // Include the hash of the class so that two objects with different types
-  // but the same field values will probably have different hashes.
-  printer->Print("hash = (19 * hash) + $classname$.class.hashCode();\n",
-    "classname", name_resolver_->GetImmutableClassName(descriptor_));
+  for (int i = 0; i < descriptor_->oneof_decl_count(); ++i) {
+    const OneofDescriptor* field = descriptor_->oneof_decl(i);
+    printer->Print(
+      "if (other.$oneof_name$Case_ != 0) {\n"
+      "  $oneof_name$Case_ = other.$oneof_name$Case_;\n"
+      "}\n",
+      "oneof_name", context_->GetOneofGeneratorInfo(field)->name);
+  }
 
-  // hashCode non-oneofs.
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = descriptor_->field(i);
-    if (field->containing_oneof() == NULL) {
-      const FieldGeneratorInfo* info = context_->GetFieldGeneratorInfo(field);
-      bool check_has_bits = CheckHasBitsForEqualsAndHashCode(field);
-      if (check_has_bits) {
-        printer->Print(
-          "if (has$name$()) {\n",
-          "name", info->capitalized_name);
-        printer->Indent();
-      }
-      field_generators_.get(field).GenerateHashCode(printer);
-      if (check_has_bits) {
-        printer->Outdent();
-        printer->Print("}\n");
-      }
+  if (GenerateHasBits(descriptor_)) {
+    // Integers for bit fields.
+    int totalBits = 0;
+    for (int i = 0; i < descriptor_->field_count(); i++) {
+      totalBits += field_generators_.get(descriptor_->field(i))
+          .GetNumBitsForMessage();
     }
-  }
+    int totalInts = (totalBits + 31) / 32;
 
-  // hashCode oneofs.
-  for (int i = 0; i < descriptor_->oneof_decl_count(); i++) {
-    printer->Print(
-      "switch ($oneof_name$Case_) {\n",
-      "oneof_name",
-      context_->GetOneofGeneratorInfo(
-          descriptor_->oneof_decl(i))->name);
-    printer->Indent();
-    for (int j = 0; j < descriptor_->oneof_decl(i)->field_count(); j++) {
-      const FieldDescriptor* field = descriptor_->oneof_decl(i)->field(j);
+    for (int i = 0; i < totalInts; i++) {
       printer->Print(
-        "case $field_number$:\n",
-        "field_number",
-        SimpleItoa(field->number()));
-      printer->Indent();
-      field_generators_.get(field).GenerateHashCode(printer);
-      printer->Print("break;\n");
-      printer->Outdent();
+        "$bit_field_name$ |= other.$bit_field_name$;\n",
+        "bit_field_name", GetBitFieldName(i));
     }
-    printer->Print(
-      "case 0:\n"
-      "default:\n");
-    printer->Outdent();
-    printer->Print("}\n");
   }
-
-  printer->Print(
-    "hash = (29 * hash) + unknownFields.hashCode();\n");
-  printer->Print(
-    "memoizedHashCode = hash;\n"
-    "return hash;\n");
   printer->Outdent();
   printer->Print(
-    "}\n"
-    "\n");
-}
+    "}\n");
 
-// ===================================================================
 
-void ImmutableMessageLiteGenerator::
-GenerateExtensionRegistrationCode(io::Printer* printer) {
-  for (int i = 0; i < descriptor_->extension_count(); i++) {
-    ImmutableExtensionLiteGenerator(descriptor_->extension(i), context_)
-      .GenerateRegistrationCode(printer);
-  }
-
-  for (int i = 0; i < descriptor_->nested_type_count(); i++) {
-    ImmutableMessageLiteGenerator(descriptor_->nested_type(i), context_)
-      .GenerateExtensionRegistrationCode(printer);
-  }
+  printer->Print(
+    "return this;\n");
 }
 
 // ===================================================================
-void ImmutableMessageLiteGenerator::
-GenerateParsingConstructor(io::Printer* printer) {
-  google::protobuf::scoped_array<const FieldDescriptor * > sorted_fields(
-      SortFieldsByNumber(descriptor_));
-
-  printer->Print(
-      "private $classname$(\n"
-      "    com.google.protobuf.CodedInputStream input,\n"
-      "    com.google.protobuf.ExtensionRegistryLite extensionRegistry) {\n",
-      "classname", descriptor_->name());
-  printer->Indent();
-
-  // Initialize all fields to default.
-  GenerateInitializers(printer);
-
-  // Use builder bits to track mutable repeated fields.
-  int totalBuilderBits = 0;
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const ImmutableFieldLiteGenerator& field =
-        field_generators_.get(descriptor_->field(i));
-    totalBuilderBits += field.GetNumBitsForBuilder();
-  }
-  int totalBuilderInts = (totalBuilderBits + 31) / 32;
-  for (int i = 0; i < totalBuilderInts; i++) {
-    printer->Print("int mutable_$bit_field_name$ = 0;\n",
-      "bit_field_name", GetBitFieldName(i));
-  }
 
+void ImmutableMessageLiteGenerator::GenerateDynamicMethodMergeFromStream(
+    io::Printer* printer) {
   printer->Print(
+      "com.google.protobuf.CodedInputStream input =\n"
+      "    (com.google.protobuf.CodedInputStream) arg0;\n"
+      "com.google.protobuf.ExtensionRegistryLite extensionRegistry =\n"
+      "    (com.google.protobuf.ExtensionRegistryLite) arg1;\n"
       "try {\n");
   printer->Indent();
 
@@ -1156,6 +961,8 @@ GenerateParsingConstructor(io::Printer* printer) {
       "}\n");
   }
 
+  google::protobuf::scoped_array<const FieldDescriptor * > sorted_fields(
+      SortFieldsByNumber(descriptor_));
   for (int i = 0; i < descriptor_->field_count(); i++) {
     const FieldDescriptor* field = sorted_fields[i];
     uint32 tag = WireFormatLite::MakeTag(field->number(),
@@ -1209,19 +1016,54 @@ GenerateParsingConstructor(io::Printer* printer) {
       "} finally {\n");
   printer->Indent();
 
-  // Make repeated field list immutable.
-  for (int i = 0; i < descriptor_->field_count(); i++) {
-    const FieldDescriptor* field = sorted_fields[i];
-    field_generators_.get(field).GenerateParsingDoneCode(printer);
+  printer->Outdent();
+  printer->Print(
+      "}\n");     // finally
+}
+
+// ===================================================================
+
+namespace {
+bool CheckHasBitsForEqualsAndHashCode(const FieldDescriptor* field) {
+  if (field->is_repeated()) {
+    return false;
+  }
+  if (SupportFieldPresence(field->file())) {
+    return true;
   }
+  return GetJavaType(field) == JAVATYPE_MESSAGE &&
+      field->containing_oneof() == NULL;
+}
+}  // namespace
+
+// ===================================================================
 
+void ImmutableMessageLiteGenerator::
+GenerateExtensionRegistrationCode(io::Printer* printer) {
+  for (int i = 0; i < descriptor_->extension_count(); i++) {
+    ImmutableExtensionLiteGenerator(descriptor_->extension(i), context_)
+      .GenerateRegistrationCode(printer);
+  }
+
+  for (int i = 0; i < descriptor_->nested_type_count(); i++) {
+    ImmutableMessageLiteGenerator(descriptor_->nested_type(i), context_)
+      .GenerateExtensionRegistrationCode(printer);
+  }
+}
+
+// ===================================================================
+void ImmutableMessageLiteGenerator::
+GenerateConstructor(io::Printer* printer) {
   printer->Print(
-      "doneParsing();\n");
+      "private $classname$() {\n",
+      "classname", descriptor_->name());
+  printer->Indent();
+
+  // Initialize all fields to default.
+  GenerateInitializers(printer);
 
-  printer->Outdent();
   printer->Outdent();
   printer->Print(
-      "  }\n"     // finally
       "}\n");
 }
 
diff --git a/src/google/protobuf/compiler/java/java_message_lite.h b/src/google/protobuf/compiler/java/java_message_lite.h
index c8ee99bd..292c1c56 100644
--- a/src/google/protobuf/compiler/java/java_message_lite.h
+++ b/src/google/protobuf/compiler/java/java_message_lite.h
@@ -70,12 +70,13 @@ class ImmutableMessageLiteGenerator : public MessageGenerator {
   void GenerateBuilder(io::Printer* printer);
   void GenerateDynamicMethodIsInitialized(io::Printer* printer);
   void GenerateDynamicMethodMakeImmutable(io::Printer* printer);
-  void GenerateDynamicMethodMergeFrom(io::Printer* printer);
+  void GenerateDynamicMethodVisit(io::Printer* printer);
+  void GenerateDynamicMethodMergeFromStream(io::Printer* printer);
   void GenerateDynamicMethodNewBuilder(io::Printer* printer);
   void GenerateInitializers(io::Printer* printer);
   void GenerateEqualsAndHashCode(io::Printer* printer);
   void GenerateParser(io::Printer* printer);
-  void GenerateParsingConstructor(io::Printer* printer);
+  void GenerateConstructor(io::Printer* printer);
 
   Context* context_;
   ClassNameResolver* name_resolver_;
diff --git a/src/google/protobuf/compiler/java/java_plugin_unittest.cc b/src/google/protobuf/compiler/java/java_plugin_unittest.cc
index fe527623..3e4910c8 100644
--- a/src/google/protobuf/compiler/java/java_plugin_unittest.cc
+++ b/src/google/protobuf/compiler/java/java_plugin_unittest.cc
@@ -44,9 +44,10 @@
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/printer.h>
 
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/testing/file.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/compiler/java/java_primitive_field_lite.cc b/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
index d277e4f3..690dad12 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_primitive_field_lite.cc
@@ -86,9 +86,6 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
     case JAVATYPE_BOOLEAN:
       (*variables)["field_list_type"] =
           "com.google.protobuf.Internal." + capitalized_type + "List";
-      (*variables)["new_list"] = "new" + capitalized_type + "List";
-      (*variables)["new_list_with_capacity"] =
-          "new" + capitalized_type + "ListWithCapacity";
       (*variables)["empty_list"] = "empty" + capitalized_type + "List()";
       (*variables)["make_name_unmodifiable"] =
           (*variables)["name"] + "_.makeImmutable()";
@@ -98,19 +95,21 @@ void SetPrimitiveVariables(const FieldDescriptor* descriptor,
           (*variables)["name"] + "_.add" + capitalized_type;
       (*variables)["repeated_set"] =
           (*variables)["name"] + "_.set" + capitalized_type;
+      (*variables)["visit_type"] = capitalized_type;
+      (*variables)["visit_type_list"] = "visit" + capitalized_type + "List";
       break;
     default:
       (*variables)["field_list_type"] =
           "com.google.protobuf.Internal.ProtobufList<" +
           (*variables)["boxed_type"] + ">";
-      (*variables)["new_list"] = "newProtobufList";
-      (*variables)["new_list_with_capacity"] = "newProtobufListWithCapacity";
       (*variables)["empty_list"] = "emptyProtobufList()";
       (*variables)["make_name_unmodifiable"] =
           (*variables)["name"] + "_.makeImmutable()";
       (*variables)["repeated_get"] = (*variables)["name"] + "_.get";
       (*variables)["repeated_add"] = (*variables)["name"] + "_.add";
       (*variables)["repeated_set"] = (*variables)["name"] + "_.set";
+      (*variables)["visit_type"] = "ByteString";
+      (*variables)["visit_type_list"] = "visitList";
   }
 
   if (IsReferenceType(GetJavaType(descriptor))) {
@@ -297,17 +296,16 @@ GenerateBuilderClearCode(io::Printer* printer) const {
 }
 
 void ImmutablePrimitiveFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   if (SupportFieldPresence(descriptor_->file())) {
     printer->Print(variables_,
-      "if (other.has$capitalized_name$()) {\n"
-      "  set$capitalized_name$(other.get$capitalized_name$());\n"
-      "}\n");
+      "$name$_ = visitor.visit$visit_type$(\n"
+      "    has$capitalized_name$(), $name$_,\n"
+      "    other.has$capitalized_name$(), other.$name$_);\n");
   } else {
     printer->Print(variables_,
-      "if (other.get$capitalized_name$() != $default$) {\n"
-      "  set$capitalized_name$(other.get$capitalized_name$());\n"
-      "}\n");
+      "$name$_ = visitor.visit$visit_type$($name$_ != $default$, $name$_,\n"
+      "    other.$name$_ != $default$, other.$name$_);\n");
   }
 }
 
@@ -539,9 +537,10 @@ GenerateBuildingCode(io::Printer* printer) const {
 }
 
 void ImmutablePrimitiveOneofFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "set$capitalized_name$(other.get$capitalized_name$());\n");
+      "$oneof_name$_ = visitor.visitOneof$visit_type$(\n"
+      "    $has_oneof_case_message$, $oneof_name$_, other.$oneof_name$_);\n");
 }
 
 void ImmutablePrimitiveOneofFieldLiteGenerator::
@@ -641,7 +640,8 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = $new_list$($name$_);\n"
+    "    $name$_ =\n"
+    "        com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "   }\n"
     "}\n");
 
@@ -742,21 +742,9 @@ GenerateBuilderClearCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutablePrimitiveFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  // The code below does two optimizations:
-  //   1. If the other list is empty, there's nothing to do. This ensures we
-  //      don't allocate a new array if we already have an immutable one.
-  //   2. If the other list is non-empty and our current list is empty, we can
-  //      reuse the other list which is guaranteed to be immutable.
-  printer->Print(variables_,
-    "if (!other.$name$_.isEmpty()) {\n"
-    "  if ($name$_.isEmpty()) {\n"
-    "    $name$_ = other.$name$_;\n"
-    "  } else {\n"
-    "    ensure$capitalized_name$IsMutable();\n"
-    "    $name$_.addAll(other.$name$_);\n"
-    "  }\n"
-    "}\n");
+GenerateVisitCode(io::Printer* printer) const {
+  printer->Print(variables_,
+      "$name$_= visitor.$visit_type_list$($name$_, other.$name$_);\n");
 }
 
 void RepeatedImmutablePrimitiveFieldLiteGenerator::
@@ -777,7 +765,8 @@ GenerateParsingCode(io::Printer* printer) const {
   // TODO(dweis): Scan the input buffer to count and ensure capacity.
   printer->Print(variables_,
     "if (!$is_mutable$) {\n"
-    "  $name$_ = $new_list$();\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "}\n"
     "$repeated_add$(input.read$capitalized_type$());\n");
 }
@@ -794,10 +783,13 @@ GenerateParsingCodeFromPacked(io::Printer* printer) const {
     // TODO(dweis): Scan the input buffer to count, then initialize
     // appropriately.
     printer->Print(variables_,
-      "  $name$_ = $new_list$();\n");
+      "  $name$_ =\n"
+      "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n");
   } else {
     printer->Print(variables_,
-      "  $name$_ = $new_list_with_capacity$(length/$fixed_size$);\n");
+      "  final int currentSize = $name$_.size();\n"
+      "  $name$_ = $name$_.mutableCopyWithCapacity(\n"
+      "      currentSize + (length/$fixed_size$));\n");
   }
 
   // TODO(dweis): Scan the input buffer to count and ensure capacity.
diff --git a/src/google/protobuf/compiler/java/java_primitive_field_lite.h b/src/google/protobuf/compiler/java/java_primitive_field_lite.h
index ad603c2a..6cfbbb98 100644
--- a/src/google/protobuf/compiler/java/java_primitive_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_primitive_field_lite.h
@@ -69,7 +69,7 @@ class ImmutablePrimitiveFieldLiteGenerator
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
   void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
@@ -105,7 +105,7 @@ class ImmutablePrimitiveOneofFieldLiteGenerator
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
@@ -130,7 +130,7 @@ class RepeatedImmutablePrimitiveFieldLiteGenerator
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
   void GenerateBuilderClearCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateBuildingCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/java/java_string_field_lite.cc b/src/google/protobuf/compiler/java/java_string_field_lite.cc
index 9012ab5e..0b92c021 100644
--- a/src/google/protobuf/compiler/java/java_string_field_lite.cc
+++ b/src/google/protobuf/compiler/java/java_string_field_lite.cc
@@ -299,20 +299,16 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void ImmutableStringFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
+GenerateVisitCode(io::Printer* printer) const {
   if (SupportFieldPresence(descriptor_->file())) {
-    // Allow a slight breach of abstraction here in order to avoid forcing
-    // all string fields to Strings when copying fields from a Message.
     printer->Print(variables_,
-      "if (other.has$capitalized_name$()) {\n"
-      "  $set_has_field_bit_message$\n"
-      "  $name$_ = other.$name$_;\n"
-      "}\n");
+      "$name$_ = visitor.visitString(\n"
+      "    has$capitalized_name$(), $name$_,\n"
+      "    other.has$capitalized_name$(), other.$name$_);\n");
   } else {
     printer->Print(variables_,
-      "if (!other.get$capitalized_name$().isEmpty()) {\n"
-      "  $name$_ = other.$name$_;\n"
-      "}\n");
+      "$name$_ = visitor.visitString(!$name$_.isEmpty(), $name$_,\n"
+      "    !other.$name$_.isEmpty(), other.$name$_);\n");
   }
 }
 
@@ -519,12 +515,10 @@ GenerateBuilderMembers(io::Printer* printer) const {
 }
 
 void ImmutableStringOneofFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  // Allow a slight breach of abstraction here in order to avoid forcing
-  // all string fields to Strings when copying fields from a Message.
+GenerateVisitCode(io::Printer* printer) const {
   printer->Print(variables_,
-    "$set_oneof_case_message$;\n"
-    "$oneof_name$_ = other.$oneof_name$_;\n");
+    "$oneof_name$_ = visitor.visitOneofString(\n"
+    "   $has_oneof_case_message$, $oneof_name$_, other.$oneof_name$_);\n");
 }
 
 void ImmutableStringOneofFieldLiteGenerator::
@@ -645,8 +639,8 @@ GenerateMembers(io::Printer* printer) const {
   printer->Print(variables_,
     "private void ensure$capitalized_name$IsMutable() {\n"
     "  if (!$is_mutable$) {\n"
-    "    $name$_ = com.google.protobuf.GeneratedMessageLite.newProtobufList(\n"
-    "        $name$_);\n"
+    "    $name$_ =\n"
+    "        com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "   }\n"
     "}\n");
 
@@ -773,21 +767,9 @@ GenerateInitializationCode(io::Printer* printer) const {
 }
 
 void RepeatedImmutableStringFieldLiteGenerator::
-GenerateMergingCode(io::Printer* printer) const {
-  // The code below does two optimizations:
-  //   1. If the other list is empty, there's nothing to do. This ensures we
-  //      don't allocate a new array if we already have an immutable one.
-  //   2. If the other list is non-empty and our current list is empty, we can
-  //      reuse the other list which is guaranteed to be immutable.
-  printer->Print(variables_,
-    "if (!other.$name$_.isEmpty()) {\n"
-    "  if ($name$_.isEmpty()) {\n"
-    "    $name$_ = other.$name$_;\n"
-    "  } else {\n"
-    "    ensure$capitalized_name$IsMutable();\n"
-    "    $name$_.addAll(other.$name$_);\n"
-    "  }\n"
-    "}\n");
+GenerateVisitCode(io::Printer* printer) const {
+  printer->Print(variables_,
+      "$name$_= visitor.visitList($name$_, other.$name$_);\n");
 }
 
 void RepeatedImmutableStringFieldLiteGenerator::
@@ -811,7 +793,8 @@ GenerateParsingCode(io::Printer* printer) const {
   }
   printer->Print(variables_,
     "if (!$is_mutable$) {\n"
-    "  $name$_ = com.google.protobuf.GeneratedMessageLite.newProtobufList();\n"
+    "  $name$_ =\n"
+    "      com.google.protobuf.GeneratedMessageLite.mutableCopy($name$_);\n"
     "}\n");
   printer->Print(variables_,
     "$name$_.add(s);\n");
diff --git a/src/google/protobuf/compiler/java/java_string_field_lite.h b/src/google/protobuf/compiler/java/java_string_field_lite.h
index 4d9b4bd7..4148aa4d 100644
--- a/src/google/protobuf/compiler/java/java_string_field_lite.h
+++ b/src/google/protobuf/compiler/java/java_string_field_lite.h
@@ -68,7 +68,7 @@ class ImmutableStringFieldLiteGenerator : public ImmutableFieldLiteGenerator {
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
@@ -103,7 +103,7 @@ class ImmutableStringOneofFieldLiteGenerator
  private:
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateSerializationCode(io::Printer* printer) const;
   void GenerateSerializedSizeCode(io::Printer* printer) const;
@@ -126,7 +126,7 @@ class RepeatedImmutableStringFieldLiteGenerator
   void GenerateMembers(io::Printer* printer) const;
   void GenerateBuilderMembers(io::Printer* printer) const;
   void GenerateInitializationCode(io::Printer* printer) const;
-  void GenerateMergingCode(io::Printer* printer) const;
+  void GenerateVisitCode(io::Printer* printer) const;
   void GenerateDynamicMethodMakeImmutableCode(io::Printer* printer) const;
   void GenerateParsingCode(io::Printer* printer) const;
   void GenerateParsingDoneCode(io::Printer* printer) const;
diff --git a/src/google/protobuf/compiler/js/js_generator.cc b/src/google/protobuf/compiler/js/js_generator.cc
index 534a5b5b..3de61e80 100755
--- a/src/google/protobuf/compiler/js/js_generator.cc
+++ b/src/google/protobuf/compiler/js/js_generator.cc
@@ -1909,7 +1909,7 @@ void Generator::GenerateClassToObject(const GeneratorOptions& options,
 
   printer->Print(
       "  if (includeInstance) {\n"
-      "    obj.$$jspbMessageInstance = msg\n"
+      "    obj.$$jspbMessageInstance = msg;\n"
       "  }\n"
       "  return obj;\n"
       "};\n"
@@ -3032,8 +3032,7 @@ bool Generator::GenerateAll(const vector<const FileDescriptor*>& files,
       const google::protobuf::FileDescriptor* file = files[i];
 
       string filename = options.output_dir + "/" + GetJSFilename(file->name());
-      scoped_ptr<io::ZeroCopyOutputStream> output(
-          context->Open(filename));
+      google::protobuf::scoped_ptr<io::ZeroCopyOutputStream> output(context->Open(filename));
       GOOGLE_CHECK(output.get());
       io::Printer printer(output.get(), '$');
 
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc b/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
index fda51807..196b39dd 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_helpers.cc
@@ -757,10 +757,11 @@ bool HasNonZeroDefaultValue(const FieldDescriptor* field) {
     return false;
   }
 
-  if (!field->has_default_value()) {
-    // No custom default set in the proto file.
-    return false;
-  }
+  // As much as checking field->has_default_value() seems useful, it isn't
+  // because of enums. proto2 syntax allows the first item in an enum (the
+  // default) to be non zero. So checking field->has_default_value() would
+  // result in missing this non zero default.  See MessageWithOneBasedEnum in
+  // objectivec/Tests/unittest_objc.proto for a test Message to confirm this.
 
   // Some proto file set the default to the zero value, so make sure the value
   // isn't the zero case.
diff --git a/src/google/protobuf/compiler/plugin.pb.cc b/src/google/protobuf/compiler/plugin.pb.cc
index a2da8eee..e9d50a1d 100644
--- a/src/google/protobuf/compiler/plugin.pb.cc
+++ b/src/google/protobuf/compiler/plugin.pb.cc
@@ -240,6 +240,7 @@ CodeGeneratorRequest* CodeGeneratorRequest::New(::google::protobuf::Arena* arena
 }
 
 void CodeGeneratorRequest::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.compiler.CodeGeneratorRequest)
   if (has_parameter()) {
     parameter_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   }
@@ -253,7 +254,7 @@ void CodeGeneratorRequest::Clear() {
 
 bool CodeGeneratorRequest::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.compiler.CodeGeneratorRequest)
   for (;;) {
@@ -412,6 +413,7 @@ void CodeGeneratorRequest::SerializeWithCachedSizes(
 }
 
 int CodeGeneratorRequest::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.compiler.CodeGeneratorRequest)
   int total_size = 0;
 
   // optional string parameter = 2;
@@ -448,18 +450,22 @@ int CodeGeneratorRequest::ByteSize() const {
 }
 
 void CodeGeneratorRequest::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorRequest)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const CodeGeneratorRequest* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const CodeGeneratorRequest>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorRequest)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorRequest)
     MergeFrom(*source);
   }
 }
 
 void CodeGeneratorRequest::MergeFrom(const CodeGeneratorRequest& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorRequest)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   file_to_generate_.MergeFrom(from.file_to_generate_);
   proto_file_.MergeFrom(from.proto_file_);
@@ -475,12 +481,14 @@ void CodeGeneratorRequest::MergeFrom(const CodeGeneratorRequest& from) {
 }
 
 void CodeGeneratorRequest::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorRequest)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void CodeGeneratorRequest::CopyFrom(const CodeGeneratorRequest& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.compiler.CodeGeneratorRequest)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -545,6 +553,7 @@ void CodeGeneratorRequest::clear_file_to_generate() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
 }
  ::std::string* CodeGeneratorRequest::add_file_to_generate() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
   return file_to_generate_.Add();
 }
  void CodeGeneratorRequest::add_file_to_generate(const ::std::string& value) {
@@ -610,6 +619,7 @@ void CodeGeneratorRequest::clear_parameter() {
   return parameter_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* CodeGeneratorRequest::release_parameter() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorRequest.parameter)
   clear_has_parameter();
   return parameter_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -728,6 +738,7 @@ CodeGeneratorResponse_File* CodeGeneratorResponse_File::New(::google::protobuf::
 }
 
 void CodeGeneratorResponse_File::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   if (_has_bits_[0 / 32] & 7u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -747,7 +758,7 @@ void CodeGeneratorResponse_File::Clear() {
 
 bool CodeGeneratorResponse_File::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   for (;;) {
@@ -912,6 +923,7 @@ void CodeGeneratorResponse_File::SerializeWithCachedSizes(
 }
 
 int CodeGeneratorResponse_File::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 7u) {
@@ -949,18 +961,22 @@ int CodeGeneratorResponse_File::ByteSize() const {
 }
 
 void CodeGeneratorResponse_File::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const CodeGeneratorResponse_File* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const CodeGeneratorResponse_File>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorResponse.File)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorResponse.File)
     MergeFrom(*source);
   }
 }
 
 void CodeGeneratorResponse_File::MergeFrom(const CodeGeneratorResponse_File& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name()) {
@@ -982,12 +998,14 @@ void CodeGeneratorResponse_File::MergeFrom(const CodeGeneratorResponse_File& fro
 }
 
 void CodeGeneratorResponse_File::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void CodeGeneratorResponse_File::CopyFrom(const CodeGeneratorResponse_File& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse.File)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1088,6 +1106,7 @@ CodeGeneratorResponse* CodeGeneratorResponse::New(::google::protobuf::Arena* are
 }
 
 void CodeGeneratorResponse::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.compiler.CodeGeneratorResponse)
   if (has_error()) {
     error_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   }
@@ -1100,7 +1119,7 @@ void CodeGeneratorResponse::Clear() {
 
 bool CodeGeneratorResponse::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.compiler.CodeGeneratorResponse)
   for (;;) {
@@ -1219,6 +1238,7 @@ void CodeGeneratorResponse::SerializeWithCachedSizes(
 }
 
 int CodeGeneratorResponse::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.compiler.CodeGeneratorResponse)
   int total_size = 0;
 
   // optional string error = 1;
@@ -1248,18 +1268,22 @@ int CodeGeneratorResponse::ByteSize() const {
 }
 
 void CodeGeneratorResponse::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const CodeGeneratorResponse* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const CodeGeneratorResponse>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.compiler.CodeGeneratorResponse)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.compiler.CodeGeneratorResponse)
     MergeFrom(*source);
   }
 }
 
 void CodeGeneratorResponse::MergeFrom(const CodeGeneratorResponse& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.compiler.CodeGeneratorResponse)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   file_.MergeFrom(from.file_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -1274,12 +1298,14 @@ void CodeGeneratorResponse::MergeFrom(const CodeGeneratorResponse& from) {
 }
 
 void CodeGeneratorResponse::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void CodeGeneratorResponse::CopyFrom(const CodeGeneratorResponse& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.compiler.CodeGeneratorResponse)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1353,6 +1379,7 @@ void CodeGeneratorResponse_File::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* CodeGeneratorResponse_File::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1406,6 +1433,7 @@ void CodeGeneratorResponse_File::clear_insertion_point() {
   return insertion_point_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* CodeGeneratorResponse_File::release_insertion_point() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
   clear_has_insertion_point();
   return insertion_point_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1459,6 +1487,7 @@ void CodeGeneratorResponse_File::clear_content() {
   return content_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* CodeGeneratorResponse_File::release_content() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.content)
   clear_has_content();
   return content_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1516,6 +1545,7 @@ void CodeGeneratorResponse::clear_error() {
   return error_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* CodeGeneratorResponse::release_error() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.error)
   clear_has_error();
   return error_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/compiler/plugin.pb.h b/src/google/protobuf/compiler/plugin.pb.h
index 0a03e979..510202f0 100644
--- a/src/google/protobuf/compiler/plugin.pb.h
+++ b/src/google/protobuf/compiler/plugin.pb.h
@@ -437,6 +437,7 @@ inline void CodeGeneratorRequest::set_file_to_generate(int index, const char* va
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
 }
 inline ::std::string* CodeGeneratorRequest::add_file_to_generate() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.compiler.CodeGeneratorRequest.file_to_generate)
   return file_to_generate_.Add();
 }
 inline void CodeGeneratorRequest::add_file_to_generate(const ::std::string& value) {
@@ -502,6 +503,7 @@ inline ::std::string* CodeGeneratorRequest::mutable_parameter() {
   return parameter_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* CodeGeneratorRequest::release_parameter() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorRequest.parameter)
   clear_has_parameter();
   return parameter_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -589,6 +591,7 @@ inline ::std::string* CodeGeneratorResponse_File::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* CodeGeneratorResponse_File::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -642,6 +645,7 @@ inline ::std::string* CodeGeneratorResponse_File::mutable_insertion_point() {
   return insertion_point_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* CodeGeneratorResponse_File::release_insertion_point() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.insertion_point)
   clear_has_insertion_point();
   return insertion_point_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -695,6 +699,7 @@ inline ::std::string* CodeGeneratorResponse_File::mutable_content() {
   return content_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* CodeGeneratorResponse_File::release_content() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.File.content)
   clear_has_content();
   return content_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -752,6 +757,7 @@ inline ::std::string* CodeGeneratorResponse::mutable_error() {
   return error_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* CodeGeneratorResponse::release_error() {
+  // @@protoc_insertion_point(field_release:google.protobuf.compiler.CodeGeneratorResponse.error)
   clear_has_error();
   return error_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/compiler/python/python_plugin_unittest.cc b/src/google/protobuf/compiler/python/python_plugin_unittest.cc
index e82bbae7..23f2449c 100644
--- a/src/google/protobuf/compiler/python/python_plugin_unittest.cc
+++ b/src/google/protobuf/compiler/python/python_plugin_unittest.cc
@@ -44,9 +44,10 @@
 #include <google/protobuf/io/zero_copy_stream.h>
 #include <google/protobuf/io/printer.h>
 
+#include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
-#include <google/protobuf/testing/file.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/descriptor.cc b/src/google/protobuf/descriptor.cc
index 78a34617..56e11fa9 100644
--- a/src/google/protobuf/descriptor.cc
+++ b/src/google/protobuf/descriptor.cc
@@ -357,13 +357,20 @@ void DeleteAllowedProto3Extendee() {
 
 void InitAllowedProto3Extendee() {
   allowed_proto3_extendees_ = new set<string>;
-  allowed_proto3_extendees_->insert("google.protobuf.FileOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.MessageOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.FieldOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.EnumOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.EnumValueOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.ServiceOptions");
-  allowed_proto3_extendees_->insert("google.protobuf.MethodOptions");
+  const char* kOptionNames[] = {
+      "FileOptions",      "MessageOptions", "FieldOptions", "EnumOptions",
+      "EnumValueOptions", "ServiceOptions", "MethodOptions"};
+  for (int i = 0; i < GOOGLE_ARRAYSIZE(kOptionNames); ++i) {
+    // descriptor.proto has a different package name in opensource. We allow
+    // both so the opensource protocol compiler can also compile internal
+    // proto3 files with custom options. See: b/27567912
+    allowed_proto3_extendees_->insert(string("google.protobuf.") +
+                                      kOptionNames[i]);
+    // Split the word to trick the opensource processing scripts so they
+    // will keep the origial package name.
+    allowed_proto3_extendees_->insert(string("proto") + "2." + kOptionNames[i]);
+  }
+
   google::protobuf::internal::OnShutdown(&DeleteAllowedProto3Extendee);
 }
 
@@ -2766,6 +2773,9 @@ class DescriptorBuilder {
  private:
   friend class OptionInterpreter;
 
+  // Non-recursive part of BuildFile functionality.
+  const FileDescriptor* BuildFileImpl(const FileDescriptorProto& proto);
+
   const DescriptorPool* pool_;
   DescriptorPool::Tables* tables_;  // for convenience
   DescriptorPool::ErrorCollector* error_collector_;
@@ -3834,7 +3844,11 @@ const FileDescriptor* DescriptorBuilder::BuildFile(
     }
     tables_->pending_files_.pop_back();
   }
+  return BuildFileImpl(proto);
+}
 
+const FileDescriptor* DescriptorBuilder::BuildFileImpl(
+    const FileDescriptorProto& proto) {
   // Checkpoint the tables so that we can roll back if something goes wrong.
   tables_->AddCheckpoint();
 
@@ -5113,11 +5127,6 @@ void DescriptorBuilder::ValidateProto3(
   for (int i = 0; i < file->enum_type_count(); ++i) {
     ValidateProto3Enum(file->enum_types_ + i, proto.enum_type(i));
   }
-  if (IsLite(file)) {
-    AddError(file->name(), proto,
-             DescriptorPool::ErrorCollector::OTHER,
-             "Lite runtime is not supported in proto3.");
-  }
 }
 
 static string ToLowercaseWithoutUnderscores(const string& name) {
diff --git a/src/google/protobuf/descriptor.pb.cc b/src/google/protobuf/descriptor.pb.cc
index 1338537e..4d5c4d99 100644
--- a/src/google/protobuf/descriptor.pb.cc
+++ b/src/google/protobuf/descriptor.pb.cc
@@ -944,6 +944,7 @@ FileDescriptorSet* FileDescriptorSet::New(::google::protobuf::Arena* arena) cons
 }
 
 void FileDescriptorSet::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FileDescriptorSet)
   file_.Clear();
   ::memset(_has_bits_, 0, sizeof(_has_bits_));
   if (_internal_metadata_.have_unknown_fields()) {
@@ -953,7 +954,7 @@ void FileDescriptorSet::Clear() {
 
 bool FileDescriptorSet::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FileDescriptorSet)
   for (;;) {
@@ -1034,6 +1035,7 @@ void FileDescriptorSet::SerializeWithCachedSizes(
 }
 
 int FileDescriptorSet::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FileDescriptorSet)
   int total_size = 0;
 
   // repeated .google.protobuf.FileDescriptorProto file = 1;
@@ -1056,18 +1058,22 @@ int FileDescriptorSet::ByteSize() const {
 }
 
 void FileDescriptorSet::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileDescriptorSet)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FileDescriptorSet* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FileDescriptorSet>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileDescriptorSet)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileDescriptorSet)
     MergeFrom(*source);
   }
 }
 
 void FileDescriptorSet::MergeFrom(const FileDescriptorSet& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileDescriptorSet)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   file_.MergeFrom(from.file_);
   if (from._internal_metadata_.have_unknown_fields()) {
@@ -1076,12 +1082,14 @@ void FileDescriptorSet::MergeFrom(const FileDescriptorSet& from) {
 }
 
 void FileDescriptorSet::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileDescriptorSet)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FileDescriptorSet::CopyFrom(const FileDescriptorSet& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FileDescriptorSet)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1235,6 +1243,7 @@ FileDescriptorProto* FileDescriptorProto::New(::google::protobuf::Arena* arena)
 }
 
 void FileDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FileDescriptorProto)
   if (_has_bits_[0 / 32] & 3u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -1269,7 +1278,7 @@ void FileDescriptorProto::Clear() {
 
 bool FileDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FileDescriptorProto)
   for (;;) {
@@ -1704,6 +1713,7 @@ void FileDescriptorProto::SerializeWithCachedSizes(
 }
 
 int FileDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FileDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 3u) {
@@ -1816,18 +1826,22 @@ int FileDescriptorProto::ByteSize() const {
 }
 
 void FileDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FileDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FileDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void FileDescriptorProto::MergeFrom(const FileDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   dependency_.MergeFrom(from.dependency_);
   public_dependency_.MergeFrom(from.public_dependency_);
@@ -1864,12 +1878,14 @@ void FileDescriptorProto::MergeFrom(const FileDescriptorProto& from) {
 }
 
 void FileDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FileDescriptorProto::CopyFrom(const FileDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FileDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1960,6 +1976,7 @@ void FileDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2013,6 +2030,7 @@ void FileDescriptorProto::clear_package() {
   return package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileDescriptorProto::release_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.package)
   clear_has_package();
   return package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2055,6 +2073,7 @@ void FileDescriptorProto::clear_dependency() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.FileDescriptorProto.dependency)
 }
  ::std::string* FileDescriptorProto::add_dependency() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.FileDescriptorProto.dependency)
   return dependency_.Add();
 }
  void FileDescriptorProto::add_dependency(const ::std::string& value) {
@@ -2287,6 +2306,7 @@ const ::google::protobuf::FileOptions& FileDescriptorProto::options() const {
   return options_;
 }
 ::google::protobuf::FileOptions* FileDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::FileOptions* temp = options_;
   options_ = NULL;
@@ -2330,6 +2350,7 @@ const ::google::protobuf::SourceCodeInfo& FileDescriptorProto::source_code_info(
   return source_code_info_;
 }
 ::google::protobuf::SourceCodeInfo* FileDescriptorProto::release_source_code_info() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.source_code_info)
   clear_has_source_code_info();
   ::google::protobuf::SourceCodeInfo* temp = source_code_info_;
   source_code_info_ = NULL;
@@ -2386,6 +2407,7 @@ void FileDescriptorProto::clear_syntax() {
   return syntax_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileDescriptorProto::release_syntax() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.syntax)
   clear_has_syntax();
   return syntax_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2468,8 +2490,17 @@ DescriptorProto_ExtensionRange* DescriptorProto_ExtensionRange::New(::google::pr
 }
 
 void DescriptorProto_ExtensionRange::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.DescriptorProto.ExtensionRange)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(DescriptorProto_ExtensionRange, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<DescriptorProto_ExtensionRange*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -2489,7 +2520,7 @@ void DescriptorProto_ExtensionRange::Clear() {
 
 bool DescriptorProto_ExtensionRange::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.DescriptorProto.ExtensionRange)
   for (;;) {
@@ -2590,6 +2621,7 @@ void DescriptorProto_ExtensionRange::SerializeWithCachedSizes(
 }
 
 int DescriptorProto_ExtensionRange::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.DescriptorProto.ExtensionRange)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 3u) {
@@ -2620,18 +2652,22 @@ int DescriptorProto_ExtensionRange::ByteSize() const {
 }
 
 void DescriptorProto_ExtensionRange::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto.ExtensionRange)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const DescriptorProto_ExtensionRange* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const DescriptorProto_ExtensionRange>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto.ExtensionRange)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto.ExtensionRange)
     MergeFrom(*source);
   }
 }
 
 void DescriptorProto_ExtensionRange::MergeFrom(const DescriptorProto_ExtensionRange& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto.ExtensionRange)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_start()) {
@@ -2647,12 +2683,14 @@ void DescriptorProto_ExtensionRange::MergeFrom(const DescriptorProto_ExtensionRa
 }
 
 void DescriptorProto_ExtensionRange::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto.ExtensionRange)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void DescriptorProto_ExtensionRange::CopyFrom(const DescriptorProto_ExtensionRange& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.DescriptorProto.ExtensionRange)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2751,8 +2789,17 @@ DescriptorProto_ReservedRange* DescriptorProto_ReservedRange::New(::google::prot
 }
 
 void DescriptorProto_ReservedRange::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.DescriptorProto.ReservedRange)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(DescriptorProto_ReservedRange, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<DescriptorProto_ReservedRange*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -2772,7 +2819,7 @@ void DescriptorProto_ReservedRange::Clear() {
 
 bool DescriptorProto_ReservedRange::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.DescriptorProto.ReservedRange)
   for (;;) {
@@ -2873,6 +2920,7 @@ void DescriptorProto_ReservedRange::SerializeWithCachedSizes(
 }
 
 int DescriptorProto_ReservedRange::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.DescriptorProto.ReservedRange)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 3u) {
@@ -2903,18 +2951,22 @@ int DescriptorProto_ReservedRange::ByteSize() const {
 }
 
 void DescriptorProto_ReservedRange::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto.ReservedRange)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const DescriptorProto_ReservedRange* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const DescriptorProto_ReservedRange>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto.ReservedRange)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto.ReservedRange)
     MergeFrom(*source);
   }
 }
 
 void DescriptorProto_ReservedRange::MergeFrom(const DescriptorProto_ReservedRange& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto.ReservedRange)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_start()) {
@@ -2930,12 +2982,14 @@ void DescriptorProto_ReservedRange::MergeFrom(const DescriptorProto_ReservedRang
 }
 
 void DescriptorProto_ReservedRange::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto.ReservedRange)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void DescriptorProto_ReservedRange::CopyFrom(const DescriptorProto_ReservedRange& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.DescriptorProto.ReservedRange)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -3046,6 +3100,7 @@ DescriptorProto* DescriptorProto::New(::google::protobuf::Arena* arena) const {
 }
 
 void DescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.DescriptorProto)
   if (_has_bits_[0 / 32] & 129u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -3070,7 +3125,7 @@ void DescriptorProto::Clear() {
 
 bool DescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.DescriptorProto)
   for (;;) {
@@ -3429,6 +3484,7 @@ void DescriptorProto::SerializeWithCachedSizes(
 }
 
 int DescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.DescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 129u) {
@@ -3522,18 +3578,22 @@ int DescriptorProto::ByteSize() const {
 }
 
 void DescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const DescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const DescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void DescriptorProto::MergeFrom(const DescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   field_.MergeFrom(from.field_);
   extension_.MergeFrom(from.extension_);
@@ -3558,12 +3618,14 @@ void DescriptorProto::MergeFrom(const DescriptorProto& from) {
 }
 
 void DescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void DescriptorProto::CopyFrom(const DescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.DescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -3756,6 +3818,7 @@ void DescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* DescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.DescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -3976,6 +4039,7 @@ const ::google::protobuf::MessageOptions& DescriptorProto::options() const {
   return options_;
 }
 ::google::protobuf::MessageOptions* DescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.DescriptorProto.options)
   clear_has_options();
   ::google::protobuf::MessageOptions* temp = options_;
   options_ = NULL;
@@ -4051,6 +4115,7 @@ void DescriptorProto::clear_reserved_name() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.DescriptorProto.reserved_name)
 }
  ::std::string* DescriptorProto::add_reserved_name() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.DescriptorProto.reserved_name)
   return reserved_name_.Add();
 }
  void DescriptorProto::add_reserved_name(const ::std::string& value) {
@@ -4245,6 +4310,7 @@ FieldDescriptorProto* FieldDescriptorProto::New(::google::protobuf::Arena* arena
 }
 
 void FieldDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FieldDescriptorProto)
   if (_has_bits_[0 / 32] & 255u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -4279,7 +4345,7 @@ void FieldDescriptorProto::Clear() {
 
 bool FieldDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FieldDescriptorProto)
   for (;;) {
@@ -4660,6 +4726,7 @@ void FieldDescriptorProto::SerializeWithCachedSizes(
 }
 
 int FieldDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FieldDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 255u) {
@@ -4746,18 +4813,22 @@ int FieldDescriptorProto::ByteSize() const {
 }
 
 void FieldDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FieldDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FieldDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void FieldDescriptorProto::MergeFrom(const FieldDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name()) {
@@ -4804,12 +4875,14 @@ void FieldDescriptorProto::MergeFrom(const FieldDescriptorProto& from) {
 }
 
 void FieldDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FieldDescriptorProto::CopyFrom(const FieldDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FieldDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -4894,6 +4967,7 @@ void FieldDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FieldDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5021,6 +5095,7 @@ void FieldDescriptorProto::clear_type_name() {
   return type_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FieldDescriptorProto::release_type_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.type_name)
   clear_has_type_name();
   return type_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5074,6 +5149,7 @@ void FieldDescriptorProto::clear_extendee() {
   return extendee_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FieldDescriptorProto::release_extendee() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.extendee)
   clear_has_extendee();
   return extendee_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5127,6 +5203,7 @@ void FieldDescriptorProto::clear_default_value() {
   return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FieldDescriptorProto::release_default_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.default_value)
   clear_has_default_value();
   return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5204,6 +5281,7 @@ void FieldDescriptorProto::clear_json_name() {
   return json_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FieldDescriptorProto::release_json_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.json_name)
   clear_has_json_name();
   return json_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5244,6 +5322,7 @@ const ::google::protobuf::FieldOptions& FieldDescriptorProto::options() const {
   return options_;
 }
 ::google::protobuf::FieldOptions* FieldDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::FieldOptions* temp = options_;
   options_ = NULL;
@@ -5329,6 +5408,7 @@ OneofDescriptorProto* OneofDescriptorProto::New(::google::protobuf::Arena* arena
 }
 
 void OneofDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.OneofDescriptorProto)
   if (has_name()) {
     name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   }
@@ -5340,7 +5420,7 @@ void OneofDescriptorProto::Clear() {
 
 bool OneofDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.OneofDescriptorProto)
   for (;;) {
@@ -5429,6 +5509,7 @@ void OneofDescriptorProto::SerializeWithCachedSizes(
 }
 
 int OneofDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.OneofDescriptorProto)
   int total_size = 0;
 
   // optional string name = 1;
@@ -5450,18 +5531,22 @@ int OneofDescriptorProto::ByteSize() const {
 }
 
 void OneofDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.OneofDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const OneofDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const OneofDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.OneofDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.OneofDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void OneofDescriptorProto::MergeFrom(const OneofDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.OneofDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name()) {
@@ -5475,12 +5560,14 @@ void OneofDescriptorProto::MergeFrom(const OneofDescriptorProto& from) {
 }
 
 void OneofDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.OneofDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void OneofDescriptorProto::CopyFrom(const OneofDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.OneofDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -5553,6 +5640,7 @@ void OneofDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* OneofDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.OneofDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5640,6 +5728,7 @@ EnumDescriptorProto* EnumDescriptorProto::New(::google::protobuf::Arena* arena)
 }
 
 void EnumDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.EnumDescriptorProto)
   if (_has_bits_[0 / 32] & 5u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -5657,7 +5746,7 @@ void EnumDescriptorProto::Clear() {
 
 bool EnumDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.EnumDescriptorProto)
   for (;;) {
@@ -5802,6 +5891,7 @@ void EnumDescriptorProto::SerializeWithCachedSizes(
 }
 
 int EnumDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.EnumDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 5u) {
@@ -5840,18 +5930,22 @@ int EnumDescriptorProto::ByteSize() const {
 }
 
 void EnumDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const EnumDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const EnumDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void EnumDescriptorProto::MergeFrom(const EnumDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   value_.MergeFrom(from.value_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -5869,12 +5963,14 @@ void EnumDescriptorProto::MergeFrom(const EnumDescriptorProto& from) {
 }
 
 void EnumDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void EnumDescriptorProto::CopyFrom(const EnumDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.EnumDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -5953,6 +6049,7 @@ void EnumDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* EnumDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6023,6 +6120,7 @@ const ::google::protobuf::EnumOptions& EnumDescriptorProto::options() const {
   return options_;
 }
 ::google::protobuf::EnumOptions* EnumDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::EnumOptions* temp = options_;
   options_ = NULL;
@@ -6114,6 +6212,7 @@ EnumValueDescriptorProto* EnumValueDescriptorProto::New(::google::protobuf::Aren
 }
 
 void EnumValueDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.EnumValueDescriptorProto)
   if (_has_bits_[0 / 32] & 7u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -6131,7 +6230,7 @@ void EnumValueDescriptorProto::Clear() {
 
 bool EnumValueDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.EnumValueDescriptorProto)
   for (;;) {
@@ -6271,6 +6370,7 @@ void EnumValueDescriptorProto::SerializeWithCachedSizes(
 }
 
 int EnumValueDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.EnumValueDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 7u) {
@@ -6308,18 +6408,22 @@ int EnumValueDescriptorProto::ByteSize() const {
 }
 
 void EnumValueDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValueDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const EnumValueDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const EnumValueDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValueDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValueDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void EnumValueDescriptorProto::MergeFrom(const EnumValueDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValueDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name()) {
@@ -6339,12 +6443,14 @@ void EnumValueDescriptorProto::MergeFrom(const EnumValueDescriptorProto& from) {
 }
 
 void EnumValueDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValueDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void EnumValueDescriptorProto::CopyFrom(const EnumValueDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.EnumValueDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -6422,6 +6528,7 @@ void EnumValueDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* EnumValueDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValueDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6486,6 +6593,7 @@ const ::google::protobuf::EnumValueOptions& EnumValueDescriptorProto::options()
   return options_;
 }
 ::google::protobuf::EnumValueOptions* EnumValueDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValueDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::EnumValueOptions* temp = options_;
   options_ = NULL;
@@ -6576,6 +6684,7 @@ ServiceDescriptorProto* ServiceDescriptorProto::New(::google::protobuf::Arena* a
 }
 
 void ServiceDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.ServiceDescriptorProto)
   if (_has_bits_[0 / 32] & 5u) {
     if (has_name()) {
       name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -6593,7 +6702,7 @@ void ServiceDescriptorProto::Clear() {
 
 bool ServiceDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.ServiceDescriptorProto)
   for (;;) {
@@ -6738,6 +6847,7 @@ void ServiceDescriptorProto::SerializeWithCachedSizes(
 }
 
 int ServiceDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.ServiceDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 5u) {
@@ -6776,18 +6886,22 @@ int ServiceDescriptorProto::ByteSize() const {
 }
 
 void ServiceDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ServiceDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const ServiceDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const ServiceDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ServiceDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ServiceDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void ServiceDescriptorProto::MergeFrom(const ServiceDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ServiceDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   method_.MergeFrom(from.method_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -6805,12 +6919,14 @@ void ServiceDescriptorProto::MergeFrom(const ServiceDescriptorProto& from) {
 }
 
 void ServiceDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ServiceDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void ServiceDescriptorProto::CopyFrom(const ServiceDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.ServiceDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -6889,6 +7005,7 @@ void ServiceDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* ServiceDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.ServiceDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6959,6 +7076,7 @@ const ::google::protobuf::ServiceOptions& ServiceDescriptorProto::options() cons
   return options_;
 }
 ::google::protobuf::ServiceOptions* ServiceDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.ServiceDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::ServiceOptions* temp = options_;
   options_ = NULL;
@@ -7058,8 +7176,17 @@ MethodDescriptorProto* MethodDescriptorProto::New(::google::protobuf::Arena* are
 }
 
 void MethodDescriptorProto::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.MethodDescriptorProto)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(MethodDescriptorProto, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<MethodDescriptorProto*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -7093,7 +7220,7 @@ void MethodDescriptorProto::Clear() {
 
 bool MethodDescriptorProto::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.MethodDescriptorProto)
   for (;;) {
@@ -7334,6 +7461,7 @@ void MethodDescriptorProto::SerializeWithCachedSizes(
 }
 
 int MethodDescriptorProto::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.MethodDescriptorProto)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 63u) {
@@ -7388,18 +7516,22 @@ int MethodDescriptorProto::ByteSize() const {
 }
 
 void MethodDescriptorProto::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MethodDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const MethodDescriptorProto* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const MethodDescriptorProto>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MethodDescriptorProto)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MethodDescriptorProto)
     MergeFrom(*source);
   }
 }
 
 void MethodDescriptorProto::MergeFrom(const MethodDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MethodDescriptorProto)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name()) {
@@ -7430,12 +7562,14 @@ void MethodDescriptorProto::MergeFrom(const MethodDescriptorProto& from) {
 }
 
 void MethodDescriptorProto::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MethodDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void MethodDescriptorProto::CopyFrom(const MethodDescriptorProto& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.MethodDescriptorProto)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -7516,6 +7650,7 @@ void MethodDescriptorProto::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* MethodDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7569,6 +7704,7 @@ void MethodDescriptorProto::clear_input_type() {
   return input_type_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* MethodDescriptorProto::release_input_type() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.input_type)
   clear_has_input_type();
   return input_type_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7622,6 +7758,7 @@ void MethodDescriptorProto::clear_output_type() {
   return output_type_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* MethodDescriptorProto::release_output_type() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.output_type)
   clear_has_output_type();
   return output_type_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7662,6 +7799,7 @@ const ::google::protobuf::MethodOptions& MethodDescriptorProto::options() const
   return options_;
 }
 ::google::protobuf::MethodOptions* MethodDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::MethodOptions* temp = options_;
   options_ = NULL;
@@ -7849,9 +7987,18 @@ FileOptions* FileOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void FileOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FileOptions)
   _extensions_.Clear();
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(FileOptions, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<FileOptions*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -7893,7 +8040,7 @@ void FileOptions::Clear() {
 
 bool FileOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FileOptions)
   for (;;) {
@@ -8409,6 +8556,7 @@ void FileOptions::SerializeWithCachedSizes(
 }
 
 int FileOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FileOptions)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 255u) {
@@ -8518,18 +8666,22 @@ int FileOptions::ByteSize() const {
 }
 
 void FileOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FileOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FileOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FileOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FileOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FileOptions)
     MergeFrom(*source);
   }
 }
 
 void FileOptions::MergeFrom(const FileOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FileOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -8590,12 +8742,14 @@ void FileOptions::MergeFrom(const FileOptions& from) {
 }
 
 void FileOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FileOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FileOptions::CopyFrom(const FileOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FileOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -8685,6 +8839,7 @@ void FileOptions::clear_java_package() {
   return java_package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileOptions::release_java_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.java_package)
   clear_has_java_package();
   return java_package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -8738,6 +8893,7 @@ void FileOptions::clear_java_outer_classname() {
   return java_outer_classname_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileOptions::release_java_outer_classname() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.java_outer_classname)
   clear_has_java_outer_classname();
   return java_outer_classname_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -8888,6 +9044,7 @@ void FileOptions::clear_go_package() {
   return go_package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileOptions::release_go_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.go_package)
   clear_has_go_package();
   return go_package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -9061,6 +9218,7 @@ void FileOptions::clear_objc_class_prefix() {
   return objc_class_prefix_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileOptions::release_objc_class_prefix() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.objc_class_prefix)
   clear_has_objc_class_prefix();
   return objc_class_prefix_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -9114,6 +9272,7 @@ void FileOptions::clear_csharp_namespace() {
   return csharp_namespace_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* FileOptions::release_csharp_namespace() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.csharp_namespace)
   clear_has_csharp_namespace();
   return csharp_namespace_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -9231,9 +9390,18 @@ MessageOptions* MessageOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void MessageOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.MessageOptions)
   _extensions_.Clear();
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(MessageOptions, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<MessageOptions*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -9254,7 +9422,7 @@ void MessageOptions::Clear() {
 
 bool MessageOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.MessageOptions)
   for (;;) {
@@ -9448,6 +9616,7 @@ void MessageOptions::SerializeWithCachedSizes(
 }
 
 int MessageOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.MessageOptions)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 15u) {
@@ -9494,18 +9663,22 @@ int MessageOptions::ByteSize() const {
 }
 
 void MessageOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MessageOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const MessageOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const MessageOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MessageOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MessageOptions)
     MergeFrom(*source);
   }
 }
 
 void MessageOptions::MergeFrom(const MessageOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MessageOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -9529,12 +9702,14 @@ void MessageOptions::MergeFrom(const MessageOptions& from) {
 }
 
 void MessageOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MessageOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void MessageOptions::CopyFrom(const MessageOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.MessageOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -9824,9 +9999,18 @@ FieldOptions* FieldOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void FieldOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FieldOptions)
   _extensions_.Clear();
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(FieldOptions, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<FieldOptions*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -9850,7 +10034,7 @@ void FieldOptions::Clear() {
 
 bool FieldOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FieldOptions)
   for (;;) {
@@ -10108,6 +10292,7 @@ void FieldOptions::SerializeWithCachedSizes(
 }
 
 int FieldOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FieldOptions)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 63u) {
@@ -10166,18 +10351,22 @@ int FieldOptions::ByteSize() const {
 }
 
 void FieldOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FieldOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FieldOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldOptions)
     MergeFrom(*source);
   }
 }
 
 void FieldOptions::MergeFrom(const FieldOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -10207,12 +10396,14 @@ void FieldOptions::MergeFrom(const FieldOptions& from) {
 }
 
 void FieldOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FieldOptions::CopyFrom(const FieldOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FieldOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -10500,9 +10691,18 @@ EnumOptions* EnumOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void EnumOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.EnumOptions)
   _extensions_.Clear();
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(EnumOptions, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<EnumOptions*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -10523,7 +10723,7 @@ void EnumOptions::Clear() {
 
 bool EnumOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.EnumOptions)
   for (;;) {
@@ -10667,6 +10867,7 @@ void EnumOptions::SerializeWithCachedSizes(
 }
 
 int EnumOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.EnumOptions)
   int total_size = 0;
 
   if (_has_bits_[0 / 32] & 3u) {
@@ -10703,18 +10904,22 @@ int EnumOptions::ByteSize() const {
 }
 
 void EnumOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const EnumOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const EnumOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumOptions)
     MergeFrom(*source);
   }
 }
 
 void EnumOptions::MergeFrom(const EnumOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -10732,12 +10937,14 @@ void EnumOptions::MergeFrom(const EnumOptions& from) {
 }
 
 void EnumOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void EnumOptions::CopyFrom(const EnumOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.EnumOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -10921,6 +11128,7 @@ EnumValueOptions* EnumValueOptions::New(::google::protobuf::Arena* arena) const
 }
 
 void EnumValueOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.EnumValueOptions)
   _extensions_.Clear();
   deprecated_ = false;
   uninterpreted_option_.Clear();
@@ -10932,7 +11140,7 @@ void EnumValueOptions::Clear() {
 
 bool EnumValueOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.EnumValueOptions)
   for (;;) {
@@ -11051,6 +11259,7 @@ void EnumValueOptions::SerializeWithCachedSizes(
 }
 
 int EnumValueOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.EnumValueOptions)
   int total_size = 0;
 
   // optional bool deprecated = 1 [default = false];
@@ -11080,18 +11289,22 @@ int EnumValueOptions::ByteSize() const {
 }
 
 void EnumValueOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValueOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const EnumValueOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const EnumValueOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValueOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValueOptions)
     MergeFrom(*source);
   }
 }
 
 void EnumValueOptions::MergeFrom(const EnumValueOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValueOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -11106,12 +11319,14 @@ void EnumValueOptions::MergeFrom(const EnumValueOptions& from) {
 }
 
 void EnumValueOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValueOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void EnumValueOptions::CopyFrom(const EnumValueOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.EnumValueOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -11270,6 +11485,7 @@ ServiceOptions* ServiceOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void ServiceOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.ServiceOptions)
   _extensions_.Clear();
   deprecated_ = false;
   uninterpreted_option_.Clear();
@@ -11281,7 +11497,7 @@ void ServiceOptions::Clear() {
 
 bool ServiceOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.ServiceOptions)
   for (;;) {
@@ -11400,6 +11616,7 @@ void ServiceOptions::SerializeWithCachedSizes(
 }
 
 int ServiceOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.ServiceOptions)
   int total_size = 0;
 
   // optional bool deprecated = 33 [default = false];
@@ -11429,18 +11646,22 @@ int ServiceOptions::ByteSize() const {
 }
 
 void ServiceOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ServiceOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const ServiceOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const ServiceOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ServiceOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ServiceOptions)
     MergeFrom(*source);
   }
 }
 
 void ServiceOptions::MergeFrom(const ServiceOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ServiceOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -11455,12 +11676,14 @@ void ServiceOptions::MergeFrom(const ServiceOptions& from) {
 }
 
 void ServiceOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ServiceOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void ServiceOptions::CopyFrom(const ServiceOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.ServiceOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -11619,6 +11842,7 @@ MethodOptions* MethodOptions::New(::google::protobuf::Arena* arena) const {
 }
 
 void MethodOptions::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.MethodOptions)
   _extensions_.Clear();
   deprecated_ = false;
   uninterpreted_option_.Clear();
@@ -11630,7 +11854,7 @@ void MethodOptions::Clear() {
 
 bool MethodOptions::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.MethodOptions)
   for (;;) {
@@ -11749,6 +11973,7 @@ void MethodOptions::SerializeWithCachedSizes(
 }
 
 int MethodOptions::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.MethodOptions)
   int total_size = 0;
 
   // optional bool deprecated = 33 [default = false];
@@ -11778,18 +12003,22 @@ int MethodOptions::ByteSize() const {
 }
 
 void MethodOptions::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.MethodOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const MethodOptions* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const MethodOptions>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.MethodOptions)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.MethodOptions)
     MergeFrom(*source);
   }
 }
 
 void MethodOptions::MergeFrom(const MethodOptions& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.MethodOptions)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   uninterpreted_option_.MergeFrom(from.uninterpreted_option_);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
@@ -11804,12 +12033,14 @@ void MethodOptions::MergeFrom(const MethodOptions& from) {
 }
 
 void MethodOptions::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.MethodOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void MethodOptions::CopyFrom(const MethodOptions& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.MethodOptions)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -11971,6 +12202,7 @@ UninterpretedOption_NamePart* UninterpretedOption_NamePart::New(::google::protob
 }
 
 void UninterpretedOption_NamePart::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.UninterpretedOption.NamePart)
   if (_has_bits_[0 / 32] & 3u) {
     if (has_name_part()) {
       name_part_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -11985,7 +12217,7 @@ void UninterpretedOption_NamePart::Clear() {
 
 bool UninterpretedOption_NamePart::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.UninterpretedOption.NamePart)
   for (;;) {
@@ -12099,6 +12331,7 @@ void UninterpretedOption_NamePart::SerializeWithCachedSizes(
 }
 
 int UninterpretedOption_NamePart::RequiredFieldsByteSizeFallback() const {
+// @@protoc_insertion_point(required_fields_byte_size_fallback_start:google.protobuf.UninterpretedOption.NamePart)
   int total_size = 0;
 
   if (has_name_part()) {
@@ -12116,6 +12349,7 @@ int UninterpretedOption_NamePart::RequiredFieldsByteSizeFallback() const {
   return total_size;
 }
 int UninterpretedOption_NamePart::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.UninterpretedOption.NamePart)
   int total_size = 0;
 
   if (((_has_bits_[0] & 0x00000003) ^ 0x00000003) == 0) {  // All required fields are present.
@@ -12142,18 +12376,22 @@ int UninterpretedOption_NamePart::ByteSize() const {
 }
 
 void UninterpretedOption_NamePart::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UninterpretedOption.NamePart)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const UninterpretedOption_NamePart* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const UninterpretedOption_NamePart>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UninterpretedOption.NamePart)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UninterpretedOption.NamePart)
     MergeFrom(*source);
   }
 }
 
 void UninterpretedOption_NamePart::MergeFrom(const UninterpretedOption_NamePart& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UninterpretedOption.NamePart)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from._has_bits_[0 / 32] & (0xffu << (0 % 32))) {
     if (from.has_name_part()) {
@@ -12170,12 +12408,14 @@ void UninterpretedOption_NamePart::MergeFrom(const UninterpretedOption_NamePart&
 }
 
 void UninterpretedOption_NamePart::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UninterpretedOption.NamePart)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void UninterpretedOption_NamePart::CopyFrom(const UninterpretedOption_NamePart& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.UninterpretedOption.NamePart)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -12288,8 +12528,17 @@ UninterpretedOption* UninterpretedOption::New(::google::protobuf::Arena* arena)
 }
 
 void UninterpretedOption::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.UninterpretedOption)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(UninterpretedOption, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<UninterpretedOption*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -12321,7 +12570,7 @@ void UninterpretedOption::Clear() {
 
 bool UninterpretedOption::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.UninterpretedOption)
   for (;;) {
@@ -12579,6 +12828,7 @@ void UninterpretedOption::SerializeWithCachedSizes(
 }
 
 int UninterpretedOption::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.UninterpretedOption)
   int total_size = 0;
 
   if (_has_bits_[1 / 32] & 126u) {
@@ -12643,18 +12893,22 @@ int UninterpretedOption::ByteSize() const {
 }
 
 void UninterpretedOption::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UninterpretedOption)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const UninterpretedOption* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const UninterpretedOption>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UninterpretedOption)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UninterpretedOption)
     MergeFrom(*source);
   }
 }
 
 void UninterpretedOption::MergeFrom(const UninterpretedOption& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UninterpretedOption)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   name_.MergeFrom(from.name_);
   if (from._has_bits_[1 / 32] & (0xffu << (1 % 32))) {
@@ -12686,12 +12940,14 @@ void UninterpretedOption::MergeFrom(const UninterpretedOption& from) {
 }
 
 void UninterpretedOption::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UninterpretedOption)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void UninterpretedOption::CopyFrom(const UninterpretedOption& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.UninterpretedOption)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -12771,6 +13027,7 @@ void UninterpretedOption_NamePart::clear_name_part() {
   return name_part_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* UninterpretedOption_NamePart::release_name_part() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.NamePart.name_part)
   clear_has_name_part();
   return name_part_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -12882,6 +13139,7 @@ void UninterpretedOption::clear_identifier_value() {
   return identifier_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* UninterpretedOption::release_identifier_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.identifier_value)
   clear_has_identifier_value();
   return identifier_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -13007,6 +13265,7 @@ void UninterpretedOption::clear_string_value() {
   return string_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* UninterpretedOption::release_string_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.string_value)
   clear_has_string_value();
   return string_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -13060,6 +13319,7 @@ void UninterpretedOption::clear_aggregate_value() {
   return aggregate_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* UninterpretedOption::release_aggregate_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.aggregate_value)
   clear_has_aggregate_value();
   return aggregate_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -13148,6 +13408,7 @@ SourceCodeInfo_Location* SourceCodeInfo_Location::New(::google::protobuf::Arena*
 }
 
 void SourceCodeInfo_Location::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.SourceCodeInfo.Location)
   if (_has_bits_[0 / 32] & 12u) {
     if (has_leading_comments()) {
       leading_comments_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -13167,7 +13428,7 @@ void SourceCodeInfo_Location::Clear() {
 
 bool SourceCodeInfo_Location::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.SourceCodeInfo.Location)
   for (;;) {
@@ -13417,6 +13678,7 @@ void SourceCodeInfo_Location::SerializeWithCachedSizes(
 }
 
 int SourceCodeInfo_Location::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.SourceCodeInfo.Location)
   int total_size = 0;
 
   if (_has_bits_[2 / 32] & 12u) {
@@ -13488,18 +13750,22 @@ int SourceCodeInfo_Location::ByteSize() const {
 }
 
 void SourceCodeInfo_Location::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceCodeInfo.Location)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const SourceCodeInfo_Location* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const SourceCodeInfo_Location>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceCodeInfo.Location)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceCodeInfo.Location)
     MergeFrom(*source);
   }
 }
 
 void SourceCodeInfo_Location::MergeFrom(const SourceCodeInfo_Location& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceCodeInfo.Location)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   path_.MergeFrom(from.path_);
   span_.MergeFrom(from.span_);
@@ -13520,12 +13786,14 @@ void SourceCodeInfo_Location::MergeFrom(const SourceCodeInfo_Location& from) {
 }
 
 void SourceCodeInfo_Location::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceCodeInfo.Location)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void SourceCodeInfo_Location::CopyFrom(const SourceCodeInfo_Location& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.SourceCodeInfo.Location)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -13624,6 +13892,7 @@ SourceCodeInfo* SourceCodeInfo::New(::google::protobuf::Arena* arena) const {
 }
 
 void SourceCodeInfo::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.SourceCodeInfo)
   location_.Clear();
   ::memset(_has_bits_, 0, sizeof(_has_bits_));
   if (_internal_metadata_.have_unknown_fields()) {
@@ -13633,7 +13902,7 @@ void SourceCodeInfo::Clear() {
 
 bool SourceCodeInfo::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.SourceCodeInfo)
   for (;;) {
@@ -13714,6 +13983,7 @@ void SourceCodeInfo::SerializeWithCachedSizes(
 }
 
 int SourceCodeInfo::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.SourceCodeInfo)
   int total_size = 0;
 
   // repeated .google.protobuf.SourceCodeInfo.Location location = 1;
@@ -13736,18 +14006,22 @@ int SourceCodeInfo::ByteSize() const {
 }
 
 void SourceCodeInfo::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceCodeInfo)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const SourceCodeInfo* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const SourceCodeInfo>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceCodeInfo)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceCodeInfo)
     MergeFrom(*source);
   }
 }
 
 void SourceCodeInfo::MergeFrom(const SourceCodeInfo& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceCodeInfo)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   location_.MergeFrom(from.location_);
   if (from._internal_metadata_.have_unknown_fields()) {
@@ -13756,12 +14030,14 @@ void SourceCodeInfo::MergeFrom(const SourceCodeInfo& from) {
 }
 
 void SourceCodeInfo::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceCodeInfo)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void SourceCodeInfo::CopyFrom(const SourceCodeInfo& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.SourceCodeInfo)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -13894,6 +14170,7 @@ void SourceCodeInfo_Location::clear_leading_comments() {
   return leading_comments_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* SourceCodeInfo_Location::release_leading_comments() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceCodeInfo.Location.leading_comments)
   clear_has_leading_comments();
   return leading_comments_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -13947,6 +14224,7 @@ void SourceCodeInfo_Location::clear_trailing_comments() {
   return trailing_comments_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* SourceCodeInfo_Location::release_trailing_comments() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceCodeInfo.Location.trailing_comments)
   clear_has_trailing_comments();
   return trailing_comments_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -13989,6 +14267,7 @@ void SourceCodeInfo_Location::clear_leading_detached_comments() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
 }
  ::std::string* SourceCodeInfo_Location::add_leading_detached_comments() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
   return leading_detached_comments_.Add();
 }
  void SourceCodeInfo_Location::add_leading_detached_comments(const ::std::string& value) {
@@ -14122,8 +14401,17 @@ GeneratedCodeInfo_Annotation* GeneratedCodeInfo_Annotation::New(::google::protob
 }
 
 void GeneratedCodeInfo_Annotation::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.GeneratedCodeInfo.Annotation)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(GeneratedCodeInfo_Annotation, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<GeneratedCodeInfo_Annotation*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -14149,7 +14437,7 @@ void GeneratedCodeInfo_Annotation::Clear() {
 
 bool GeneratedCodeInfo_Annotation::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.GeneratedCodeInfo.Annotation)
   for (;;) {
@@ -14330,6 +14618,7 @@ void GeneratedCodeInfo_Annotation::SerializeWithCachedSizes(
 }
 
 int GeneratedCodeInfo_Annotation::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.GeneratedCodeInfo.Annotation)
   int total_size = 0;
 
   if (_has_bits_[1 / 32] & 14u) {
@@ -14384,18 +14673,22 @@ int GeneratedCodeInfo_Annotation::ByteSize() const {
 }
 
 void GeneratedCodeInfo_Annotation::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const GeneratedCodeInfo_Annotation* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const GeneratedCodeInfo_Annotation>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.GeneratedCodeInfo.Annotation)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.GeneratedCodeInfo.Annotation)
     MergeFrom(*source);
   }
 }
 
 void GeneratedCodeInfo_Annotation::MergeFrom(const GeneratedCodeInfo_Annotation& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   path_.MergeFrom(from.path_);
   if (from._has_bits_[1 / 32] & (0xffu << (1 % 32))) {
@@ -14416,12 +14709,14 @@ void GeneratedCodeInfo_Annotation::MergeFrom(const GeneratedCodeInfo_Annotation&
 }
 
 void GeneratedCodeInfo_Annotation::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void GeneratedCodeInfo_Annotation::CopyFrom(const GeneratedCodeInfo_Annotation& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.GeneratedCodeInfo.Annotation)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -14519,6 +14814,7 @@ GeneratedCodeInfo* GeneratedCodeInfo::New(::google::protobuf::Arena* arena) cons
 }
 
 void GeneratedCodeInfo::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.GeneratedCodeInfo)
   annotation_.Clear();
   ::memset(_has_bits_, 0, sizeof(_has_bits_));
   if (_internal_metadata_.have_unknown_fields()) {
@@ -14528,7 +14824,7 @@ void GeneratedCodeInfo::Clear() {
 
 bool GeneratedCodeInfo::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.GeneratedCodeInfo)
   for (;;) {
@@ -14609,6 +14905,7 @@ void GeneratedCodeInfo::SerializeWithCachedSizes(
 }
 
 int GeneratedCodeInfo::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.GeneratedCodeInfo)
   int total_size = 0;
 
   // repeated .google.protobuf.GeneratedCodeInfo.Annotation annotation = 1;
@@ -14631,18 +14928,22 @@ int GeneratedCodeInfo::ByteSize() const {
 }
 
 void GeneratedCodeInfo::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.GeneratedCodeInfo)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const GeneratedCodeInfo* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const GeneratedCodeInfo>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.GeneratedCodeInfo)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.GeneratedCodeInfo)
     MergeFrom(*source);
   }
 }
 
 void GeneratedCodeInfo::MergeFrom(const GeneratedCodeInfo& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.GeneratedCodeInfo)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   annotation_.MergeFrom(from.annotation_);
   if (from._internal_metadata_.have_unknown_fields()) {
@@ -14651,12 +14952,14 @@ void GeneratedCodeInfo::MergeFrom(const GeneratedCodeInfo& from) {
 }
 
 void GeneratedCodeInfo::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.GeneratedCodeInfo)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void GeneratedCodeInfo::CopyFrom(const GeneratedCodeInfo& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.GeneratedCodeInfo)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -14759,6 +15062,7 @@ void GeneratedCodeInfo_Annotation::clear_source_file() {
   return source_file_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* GeneratedCodeInfo_Annotation::release_source_file() {
+  // @@protoc_insertion_point(field_release:google.protobuf.GeneratedCodeInfo.Annotation.source_file)
   clear_has_source_file();
   return source_file_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/descriptor.pb.h b/src/google/protobuf/descriptor.pb.h
index 9f15bf27..92a0a3a7 100644
--- a/src/google/protobuf/descriptor.pb.h
+++ b/src/google/protobuf/descriptor.pb.h
@@ -993,24 +993,42 @@ class LIBPROTOBUF_EXPORT FieldDescriptorProto : public ::google::protobuf::Messa
   // nested types ----------------------------------------------------
 
   typedef FieldDescriptorProto_Type Type;
-  static const Type TYPE_DOUBLE = FieldDescriptorProto_Type_TYPE_DOUBLE;
-  static const Type TYPE_FLOAT = FieldDescriptorProto_Type_TYPE_FLOAT;
-  static const Type TYPE_INT64 = FieldDescriptorProto_Type_TYPE_INT64;
-  static const Type TYPE_UINT64 = FieldDescriptorProto_Type_TYPE_UINT64;
-  static const Type TYPE_INT32 = FieldDescriptorProto_Type_TYPE_INT32;
-  static const Type TYPE_FIXED64 = FieldDescriptorProto_Type_TYPE_FIXED64;
-  static const Type TYPE_FIXED32 = FieldDescriptorProto_Type_TYPE_FIXED32;
-  static const Type TYPE_BOOL = FieldDescriptorProto_Type_TYPE_BOOL;
-  static const Type TYPE_STRING = FieldDescriptorProto_Type_TYPE_STRING;
-  static const Type TYPE_GROUP = FieldDescriptorProto_Type_TYPE_GROUP;
-  static const Type TYPE_MESSAGE = FieldDescriptorProto_Type_TYPE_MESSAGE;
-  static const Type TYPE_BYTES = FieldDescriptorProto_Type_TYPE_BYTES;
-  static const Type TYPE_UINT32 = FieldDescriptorProto_Type_TYPE_UINT32;
-  static const Type TYPE_ENUM = FieldDescriptorProto_Type_TYPE_ENUM;
-  static const Type TYPE_SFIXED32 = FieldDescriptorProto_Type_TYPE_SFIXED32;
-  static const Type TYPE_SFIXED64 = FieldDescriptorProto_Type_TYPE_SFIXED64;
-  static const Type TYPE_SINT32 = FieldDescriptorProto_Type_TYPE_SINT32;
-  static const Type TYPE_SINT64 = FieldDescriptorProto_Type_TYPE_SINT64;
+  static const Type TYPE_DOUBLE =
+    FieldDescriptorProto_Type_TYPE_DOUBLE;
+  static const Type TYPE_FLOAT =
+    FieldDescriptorProto_Type_TYPE_FLOAT;
+  static const Type TYPE_INT64 =
+    FieldDescriptorProto_Type_TYPE_INT64;
+  static const Type TYPE_UINT64 =
+    FieldDescriptorProto_Type_TYPE_UINT64;
+  static const Type TYPE_INT32 =
+    FieldDescriptorProto_Type_TYPE_INT32;
+  static const Type TYPE_FIXED64 =
+    FieldDescriptorProto_Type_TYPE_FIXED64;
+  static const Type TYPE_FIXED32 =
+    FieldDescriptorProto_Type_TYPE_FIXED32;
+  static const Type TYPE_BOOL =
+    FieldDescriptorProto_Type_TYPE_BOOL;
+  static const Type TYPE_STRING =
+    FieldDescriptorProto_Type_TYPE_STRING;
+  static const Type TYPE_GROUP =
+    FieldDescriptorProto_Type_TYPE_GROUP;
+  static const Type TYPE_MESSAGE =
+    FieldDescriptorProto_Type_TYPE_MESSAGE;
+  static const Type TYPE_BYTES =
+    FieldDescriptorProto_Type_TYPE_BYTES;
+  static const Type TYPE_UINT32 =
+    FieldDescriptorProto_Type_TYPE_UINT32;
+  static const Type TYPE_ENUM =
+    FieldDescriptorProto_Type_TYPE_ENUM;
+  static const Type TYPE_SFIXED32 =
+    FieldDescriptorProto_Type_TYPE_SFIXED32;
+  static const Type TYPE_SFIXED64 =
+    FieldDescriptorProto_Type_TYPE_SFIXED64;
+  static const Type TYPE_SINT32 =
+    FieldDescriptorProto_Type_TYPE_SINT32;
+  static const Type TYPE_SINT64 =
+    FieldDescriptorProto_Type_TYPE_SINT64;
   static inline bool Type_IsValid(int value) {
     return FieldDescriptorProto_Type_IsValid(value);
   }
@@ -1033,9 +1051,12 @@ class LIBPROTOBUF_EXPORT FieldDescriptorProto : public ::google::protobuf::Messa
   }
 
   typedef FieldDescriptorProto_Label Label;
-  static const Label LABEL_OPTIONAL = FieldDescriptorProto_Label_LABEL_OPTIONAL;
-  static const Label LABEL_REQUIRED = FieldDescriptorProto_Label_LABEL_REQUIRED;
-  static const Label LABEL_REPEATED = FieldDescriptorProto_Label_LABEL_REPEATED;
+  static const Label LABEL_OPTIONAL =
+    FieldDescriptorProto_Label_LABEL_OPTIONAL;
+  static const Label LABEL_REQUIRED =
+    FieldDescriptorProto_Label_LABEL_REQUIRED;
+  static const Label LABEL_REPEATED =
+    FieldDescriptorProto_Label_LABEL_REPEATED;
   static inline bool Label_IsValid(int value) {
     return FieldDescriptorProto_Label_IsValid(value);
   }
@@ -1868,9 +1889,12 @@ class LIBPROTOBUF_EXPORT FileOptions : public ::google::protobuf::Message {
   // nested types ----------------------------------------------------
 
   typedef FileOptions_OptimizeMode OptimizeMode;
-  static const OptimizeMode SPEED = FileOptions_OptimizeMode_SPEED;
-  static const OptimizeMode CODE_SIZE = FileOptions_OptimizeMode_CODE_SIZE;
-  static const OptimizeMode LITE_RUNTIME = FileOptions_OptimizeMode_LITE_RUNTIME;
+  static const OptimizeMode SPEED =
+    FileOptions_OptimizeMode_SPEED;
+  static const OptimizeMode CODE_SIZE =
+    FileOptions_OptimizeMode_CODE_SIZE;
+  static const OptimizeMode LITE_RUNTIME =
+    FileOptions_OptimizeMode_LITE_RUNTIME;
   static inline bool OptimizeMode_IsValid(int value) {
     return FileOptions_OptimizeMode_IsValid(value);
   }
@@ -2288,9 +2312,12 @@ class LIBPROTOBUF_EXPORT FieldOptions : public ::google::protobuf::Message {
   // nested types ----------------------------------------------------
 
   typedef FieldOptions_CType CType;
-  static const CType STRING = FieldOptions_CType_STRING;
-  static const CType CORD = FieldOptions_CType_CORD;
-  static const CType STRING_PIECE = FieldOptions_CType_STRING_PIECE;
+  static const CType STRING =
+    FieldOptions_CType_STRING;
+  static const CType CORD =
+    FieldOptions_CType_CORD;
+  static const CType STRING_PIECE =
+    FieldOptions_CType_STRING_PIECE;
   static inline bool CType_IsValid(int value) {
     return FieldOptions_CType_IsValid(value);
   }
@@ -2313,9 +2340,12 @@ class LIBPROTOBUF_EXPORT FieldOptions : public ::google::protobuf::Message {
   }
 
   typedef FieldOptions_JSType JSType;
-  static const JSType JS_NORMAL = FieldOptions_JSType_JS_NORMAL;
-  static const JSType JS_STRING = FieldOptions_JSType_JS_STRING;
-  static const JSType JS_NUMBER = FieldOptions_JSType_JS_NUMBER;
+  static const JSType JS_NORMAL =
+    FieldOptions_JSType_JS_NORMAL;
+  static const JSType JS_STRING =
+    FieldOptions_JSType_JS_STRING;
+  static const JSType JS_NUMBER =
+    FieldOptions_JSType_JS_NUMBER;
   static inline bool JSType_IsValid(int value) {
     return FieldOptions_JSType_IsValid(value);
   }
@@ -3686,6 +3716,7 @@ inline ::std::string* FileDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -3739,6 +3770,7 @@ inline ::std::string* FileDescriptorProto::mutable_package() {
   return package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileDescriptorProto::release_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.package)
   clear_has_package();
   return package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -3781,6 +3813,7 @@ inline void FileDescriptorProto::set_dependency(int index, const char* value, si
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.FileDescriptorProto.dependency)
 }
 inline ::std::string* FileDescriptorProto::add_dependency() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.FileDescriptorProto.dependency)
   return dependency_.Add();
 }
 inline void FileDescriptorProto::add_dependency(const ::std::string& value) {
@@ -4013,6 +4046,7 @@ inline ::google::protobuf::FileOptions* FileDescriptorProto::mutable_options() {
   return options_;
 }
 inline ::google::protobuf::FileOptions* FileDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::FileOptions* temp = options_;
   options_ = NULL;
@@ -4056,6 +4090,7 @@ inline ::google::protobuf::SourceCodeInfo* FileDescriptorProto::mutable_source_c
   return source_code_info_;
 }
 inline ::google::protobuf::SourceCodeInfo* FileDescriptorProto::release_source_code_info() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.source_code_info)
   clear_has_source_code_info();
   ::google::protobuf::SourceCodeInfo* temp = source_code_info_;
   source_code_info_ = NULL;
@@ -4112,6 +4147,7 @@ inline ::std::string* FileDescriptorProto::mutable_syntax() {
   return syntax_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileDescriptorProto::release_syntax() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileDescriptorProto.syntax)
   clear_has_syntax();
   return syntax_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4273,6 +4309,7 @@ inline ::std::string* DescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* DescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.DescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4493,6 +4530,7 @@ inline ::google::protobuf::MessageOptions* DescriptorProto::mutable_options() {
   return options_;
 }
 inline ::google::protobuf::MessageOptions* DescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.DescriptorProto.options)
   clear_has_options();
   ::google::protobuf::MessageOptions* temp = options_;
   options_ = NULL;
@@ -4568,6 +4606,7 @@ inline void DescriptorProto::set_reserved_name(int index, const char* value, siz
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.DescriptorProto.reserved_name)
 }
 inline ::std::string* DescriptorProto::add_reserved_name() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.DescriptorProto.reserved_name)
   return reserved_name_.Add();
 }
 inline void DescriptorProto::add_reserved_name(const ::std::string& value) {
@@ -4637,6 +4676,7 @@ inline ::std::string* FieldDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FieldDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4764,6 +4804,7 @@ inline ::std::string* FieldDescriptorProto::mutable_type_name() {
   return type_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FieldDescriptorProto::release_type_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.type_name)
   clear_has_type_name();
   return type_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4817,6 +4858,7 @@ inline ::std::string* FieldDescriptorProto::mutable_extendee() {
   return extendee_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FieldDescriptorProto::release_extendee() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.extendee)
   clear_has_extendee();
   return extendee_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4870,6 +4912,7 @@ inline ::std::string* FieldDescriptorProto::mutable_default_value() {
   return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FieldDescriptorProto::release_default_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.default_value)
   clear_has_default_value();
   return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4947,6 +4990,7 @@ inline ::std::string* FieldDescriptorProto::mutable_json_name() {
   return json_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FieldDescriptorProto::release_json_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.json_name)
   clear_has_json_name();
   return json_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -4987,6 +5031,7 @@ inline ::google::protobuf::FieldOptions* FieldDescriptorProto::mutable_options()
   return options_;
 }
 inline ::google::protobuf::FieldOptions* FieldDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FieldDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::FieldOptions* temp = options_;
   options_ = NULL;
@@ -5047,6 +5092,7 @@ inline ::std::string* OneofDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* OneofDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.OneofDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5104,6 +5150,7 @@ inline ::std::string* EnumDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* EnumDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5174,6 +5221,7 @@ inline ::google::protobuf::EnumOptions* EnumDescriptorProto::mutable_options() {
   return options_;
 }
 inline ::google::protobuf::EnumOptions* EnumDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::EnumOptions* temp = options_;
   options_ = NULL;
@@ -5234,6 +5282,7 @@ inline ::std::string* EnumValueDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* EnumValueDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValueDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5298,6 +5347,7 @@ inline ::google::protobuf::EnumValueOptions* EnumValueDescriptorProto::mutable_o
   return options_;
 }
 inline ::google::protobuf::EnumValueOptions* EnumValueDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValueDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::EnumValueOptions* temp = options_;
   options_ = NULL;
@@ -5358,6 +5408,7 @@ inline ::std::string* ServiceDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* ServiceDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.ServiceDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5428,6 +5479,7 @@ inline ::google::protobuf::ServiceOptions* ServiceDescriptorProto::mutable_optio
   return options_;
 }
 inline ::google::protobuf::ServiceOptions* ServiceDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.ServiceDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::ServiceOptions* temp = options_;
   options_ = NULL;
@@ -5488,6 +5540,7 @@ inline ::std::string* MethodDescriptorProto::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* MethodDescriptorProto::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.name)
   clear_has_name();
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5541,6 +5594,7 @@ inline ::std::string* MethodDescriptorProto::mutable_input_type() {
   return input_type_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* MethodDescriptorProto::release_input_type() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.input_type)
   clear_has_input_type();
   return input_type_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5594,6 +5648,7 @@ inline ::std::string* MethodDescriptorProto::mutable_output_type() {
   return output_type_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* MethodDescriptorProto::release_output_type() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.output_type)
   clear_has_output_type();
   return output_type_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5634,6 +5689,7 @@ inline ::google::protobuf::MethodOptions* MethodDescriptorProto::mutable_options
   return options_;
 }
 inline ::google::protobuf::MethodOptions* MethodDescriptorProto::release_options() {
+  // @@protoc_insertion_point(field_release:google.protobuf.MethodDescriptorProto.options)
   clear_has_options();
   ::google::protobuf::MethodOptions* temp = options_;
   options_ = NULL;
@@ -5742,6 +5798,7 @@ inline ::std::string* FileOptions::mutable_java_package() {
   return java_package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileOptions::release_java_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.java_package)
   clear_has_java_package();
   return java_package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5795,6 +5852,7 @@ inline ::std::string* FileOptions::mutable_java_outer_classname() {
   return java_outer_classname_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileOptions::release_java_outer_classname() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.java_outer_classname)
   clear_has_java_outer_classname();
   return java_outer_classname_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -5945,6 +6003,7 @@ inline ::std::string* FileOptions::mutable_go_package() {
   return go_package_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileOptions::release_go_package() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.go_package)
   clear_has_go_package();
   return go_package_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6118,6 +6177,7 @@ inline ::std::string* FileOptions::mutable_objc_class_prefix() {
   return objc_class_prefix_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileOptions::release_objc_class_prefix() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.objc_class_prefix)
   clear_has_objc_class_prefix();
   return objc_class_prefix_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6171,6 +6231,7 @@ inline ::std::string* FileOptions::mutable_csharp_namespace() {
   return csharp_namespace_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* FileOptions::release_csharp_namespace() {
+  // @@protoc_insertion_point(field_release:google.protobuf.FileOptions.csharp_namespace)
   clear_has_csharp_namespace();
   return csharp_namespace_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6824,6 +6885,7 @@ inline ::std::string* UninterpretedOption_NamePart::mutable_name_part() {
   return name_part_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* UninterpretedOption_NamePart::release_name_part() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.NamePart.name_part)
   clear_has_name_part();
   return name_part_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -6935,6 +6997,7 @@ inline ::std::string* UninterpretedOption::mutable_identifier_value() {
   return identifier_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* UninterpretedOption::release_identifier_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.identifier_value)
   clear_has_identifier_value();
   return identifier_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7060,6 +7123,7 @@ inline ::std::string* UninterpretedOption::mutable_string_value() {
   return string_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* UninterpretedOption::release_string_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.string_value)
   clear_has_string_value();
   return string_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7113,6 +7177,7 @@ inline ::std::string* UninterpretedOption::mutable_aggregate_value() {
   return aggregate_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* UninterpretedOption::release_aggregate_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.UninterpretedOption.aggregate_value)
   clear_has_aggregate_value();
   return aggregate_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7230,6 +7295,7 @@ inline ::std::string* SourceCodeInfo_Location::mutable_leading_comments() {
   return leading_comments_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* SourceCodeInfo_Location::release_leading_comments() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceCodeInfo.Location.leading_comments)
   clear_has_leading_comments();
   return leading_comments_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7283,6 +7349,7 @@ inline ::std::string* SourceCodeInfo_Location::mutable_trailing_comments() {
   return trailing_comments_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* SourceCodeInfo_Location::release_trailing_comments() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceCodeInfo.Location.trailing_comments)
   clear_has_trailing_comments();
   return trailing_comments_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -7325,6 +7392,7 @@ inline void SourceCodeInfo_Location::set_leading_detached_comments(int index, co
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
 }
 inline ::std::string* SourceCodeInfo_Location::add_leading_detached_comments() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.SourceCodeInfo.Location.leading_detached_comments)
   return leading_detached_comments_.Add();
 }
 inline void SourceCodeInfo_Location::add_leading_detached_comments(const ::std::string& value) {
@@ -7458,6 +7526,7 @@ inline ::std::string* GeneratedCodeInfo_Annotation::mutable_source_file() {
   return source_file_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* GeneratedCodeInfo_Annotation::release_source_file() {
+  // @@protoc_insertion_point(field_release:google.protobuf.GeneratedCodeInfo.Annotation.source_file)
   clear_has_source_file();
   return source_file_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/descriptor_unittest.cc b/src/google/protobuf/descriptor_unittest.cc
index e4720a7e..f937b9ea 100644
--- a/src/google/protobuf/descriptor_unittest.cc
+++ b/src/google/protobuf/descriptor_unittest.cc
@@ -5740,18 +5740,6 @@ TEST_F(ValidationErrorTest, ValidateProto3Enum) {
       "}");
 }
 
-TEST_F(ValidationErrorTest, ValidateProto3LiteRuntime) {
-  // Lite runtime is not supported in proto3.
-  BuildFileWithErrors(
-      "name: 'foo.proto' "
-      "syntax: 'proto3' "
-      "options { "
-      "  optimize_for: LITE_RUNTIME "
-      "} ",
-      "foo.proto: foo.proto: OTHER: Lite runtime is not supported "
-      "in proto3.\n");
-}
-
 TEST_F(ValidationErrorTest, ValidateProto3Group) {
   BuildFileWithErrors(
       "name: 'foo.proto' "
diff --git a/src/google/protobuf/duration.pb.cc b/src/google/protobuf/duration.pb.cc
index c71ce663..e3639346 100644
--- a/src/google/protobuf/duration.pb.cc
+++ b/src/google/protobuf/duration.pb.cc
@@ -179,8 +179,17 @@ Duration* Duration::New(::google::protobuf::Arena* arena) const {
 }
 
 void Duration::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Duration)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(Duration, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<Duration*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -196,7 +205,7 @@ void Duration::Clear() {
 
 bool Duration::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Duration)
   for (;;) {
@@ -288,6 +297,7 @@ void Duration::SerializeWithCachedSizes(
 }
 
 int Duration::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Duration)
   int total_size = 0;
 
   // optional int64 seconds = 1;
@@ -311,18 +321,22 @@ int Duration::ByteSize() const {
 }
 
 void Duration::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Duration)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Duration* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Duration>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Duration)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Duration)
     MergeFrom(*source);
   }
 }
 
 void Duration::MergeFrom(const Duration& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Duration)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.seconds() != 0) {
     set_seconds(from.seconds());
@@ -333,12 +347,14 @@ void Duration::MergeFrom(const Duration& from) {
 }
 
 void Duration::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Duration)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Duration::CopyFrom(const Duration& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Duration)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
diff --git a/src/google/protobuf/empty.pb.cc b/src/google/protobuf/empty.pb.cc
index 4550921b..dcf84263 100644
--- a/src/google/protobuf/empty.pb.cc
+++ b/src/google/protobuf/empty.pb.cc
@@ -186,11 +186,12 @@ Empty* Empty::New(::google::protobuf::Arena* arena) const {
 }
 
 void Empty::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Empty)
 }
 
 bool Empty::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Empty)
   for (;;) {
@@ -228,6 +229,7 @@ void Empty::SerializeWithCachedSizes(
 }
 
 int Empty::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Empty)
   int total_size = 0;
 
   GOOGLE_SAFE_CONCURRENT_WRITES_BEGIN();
@@ -237,28 +239,34 @@ int Empty::ByteSize() const {
 }
 
 void Empty::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Empty)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Empty* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Empty>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Empty)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Empty)
     MergeFrom(*source);
   }
 }
 
 void Empty::MergeFrom(const Empty& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Empty)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
 }
 
 void Empty::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Empty)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Empty::CopyFrom(const Empty& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Empty)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
diff --git a/src/google/protobuf/field_mask.pb.cc b/src/google/protobuf/field_mask.pb.cc
index 01a6ce56..c49ebceb 100644
--- a/src/google/protobuf/field_mask.pb.cc
+++ b/src/google/protobuf/field_mask.pb.cc
@@ -175,12 +175,13 @@ FieldMask* FieldMask::New(::google::protobuf::Arena* arena) const {
 }
 
 void FieldMask::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FieldMask)
   paths_.Clear();
 }
 
 bool FieldMask::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FieldMask)
   for (;;) {
@@ -262,6 +263,7 @@ void FieldMask::SerializeWithCachedSizes(
 }
 
 int FieldMask::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FieldMask)
   int total_size = 0;
 
   // repeated string paths = 1;
@@ -278,29 +280,35 @@ int FieldMask::ByteSize() const {
 }
 
 void FieldMask::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FieldMask)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FieldMask* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FieldMask>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FieldMask)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FieldMask)
     MergeFrom(*source);
   }
 }
 
 void FieldMask::MergeFrom(const FieldMask& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FieldMask)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   paths_.MergeFrom(from.paths_);
 }
 
 void FieldMask::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FieldMask)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FieldMask::CopyFrom(const FieldMask& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FieldMask)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -361,6 +369,7 @@ void FieldMask::clear_paths() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.FieldMask.paths)
 }
  ::std::string* FieldMask::add_paths() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.FieldMask.paths)
   return paths_.Add();
 }
  void FieldMask::add_paths(const ::std::string& value) {
diff --git a/src/google/protobuf/field_mask.pb.h b/src/google/protobuf/field_mask.pb.h
index 7189fd79..f5e0b655 100644
--- a/src/google/protobuf/field_mask.pb.h
+++ b/src/google/protobuf/field_mask.pb.h
@@ -164,6 +164,7 @@ inline void FieldMask::set_paths(int index, const char* value, size_t size) {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.FieldMask.paths)
 }
 inline ::std::string* FieldMask::add_paths() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.FieldMask.paths)
   return paths_.Add();
 }
 inline void FieldMask::add_paths(const ::std::string& value) {
diff --git a/src/google/protobuf/field_mask.proto b/src/google/protobuf/field_mask.proto
index b1657f5f..6af6dbe8 100644
--- a/src/google/protobuf/field_mask.proto
+++ b/src/google/protobuf/field_mask.proto
@@ -88,7 +88,7 @@ option java_generate_equals_and_hash = true;
 // operation applies to all fields (as if a FieldMask of all fields
 // had been specified).
 //
-// Note that a field mask does not necessarily applies to the
+// Note that a field mask does not necessarily apply to the
 // top-level response message. In case of a REST get operation, the
 // field mask applies directly to the response, but in case of a REST
 // list operation, the mask instead applies to each individual message
diff --git a/src/google/protobuf/generated_message_reflection.cc b/src/google/protobuf/generated_message_reflection.cc
index eee024ee..2313181c 100644
--- a/src/google/protobuf/generated_message_reflection.cc
+++ b/src/google/protobuf/generated_message_reflection.cc
@@ -412,6 +412,15 @@ void GeneratedMessageReflection::SwapField(
 #undef SWAP_ARRAYS
 
       case FieldDescriptor::CPPTYPE_STRING:
+        switch (field->options().ctype()) {
+          default:  // TODO(kenton):  Support other string reps.
+          case FieldOptions::STRING:
+            MutableRaw<RepeatedPtrFieldBase>(message1, field)->
+                Swap<GenericTypeHandler<string> >(
+                    MutableRaw<RepeatedPtrFieldBase>(message2, field));
+            break;
+        }
+        break;
       case FieldDescriptor::CPPTYPE_MESSAGE:
         if (IsMapFieldInApi(field)) {
           MutableRaw<MapFieldBase>(message1, field)->
@@ -447,16 +456,50 @@ void GeneratedMessageReflection::SwapField(
       SWAP_VALUES(ENUM  , int   );
 #undef SWAP_VALUES
       case FieldDescriptor::CPPTYPE_MESSAGE:
-        std::swap(*MutableRaw<Message*>(message1, field),
-                  *MutableRaw<Message*>(message2, field));
+        if (GetArena(message1) == GetArena(message2)) {
+          std::swap(*MutableRaw<Message*>(message1, field),
+                    *MutableRaw<Message*>(message2, field));
+        } else {
+          Message** sub_msg1 = MutableRaw<Message*>(message1, field);
+          Message** sub_msg2 = MutableRaw<Message*>(message2, field);
+          if (*sub_msg1 == NULL && *sub_msg2 == NULL) break;
+          if (*sub_msg1 && *sub_msg2) {
+            (*sub_msg1)->GetReflection()->Swap(*sub_msg1, *sub_msg2);
+            break;
+          }
+          if (*sub_msg1 == NULL) {
+            *sub_msg1 = (*sub_msg2)->New(message1->GetArena());
+            (*sub_msg1)->CopyFrom(**sub_msg2);
+            ClearField(message2, field);
+          } else {
+            *sub_msg2 = (*sub_msg1)->New(message2->GetArena());
+            (*sub_msg2)->CopyFrom(**sub_msg1);
+            ClearField(message1, field);
+          }
+        }
         break;
 
       case FieldDescriptor::CPPTYPE_STRING:
         switch (field->options().ctype()) {
           default:  // TODO(kenton):  Support other string reps.
           case FieldOptions::STRING:
-            MutableRaw<ArenaStringPtr>(message1, field)->Swap(
-                MutableRaw<ArenaStringPtr>(message2, field));
+            {
+              Arena* arena1 = GetArena(message1);
+              Arena* arena2 = GetArena(message2);
+              ArenaStringPtr* string1 =
+                  MutableRaw<ArenaStringPtr>(message1, field);
+              ArenaStringPtr* string2 =
+                  MutableRaw<ArenaStringPtr>(message2, field);
+              if (arena1 == arena2) {
+                string1->Swap(string2);
+              } else {
+                const string* default_ptr =
+                    &DefaultRaw<ArenaStringPtr>(field).Get(NULL);
+                const string temp = string1->Get(default_ptr);
+                string1->Set(default_ptr, string2->Get(default_ptr), arena1);
+                string2->Set(default_ptr, temp, arena2);
+              }
+            }
             break;
         }
         break;
@@ -1752,7 +1795,8 @@ bool GeneratedMessageReflection::InsertOrLookupMapValue(
               "InsertOrLookupMapValue",
               "Field is not a map field.");
   val->SetType(field->message_type()->FindFieldByName("value")->cpp_type());
-  return MutableRaw<MapFieldBase>(message, field)->InsertMapValue(key, val);
+  return MutableRaw<MapFieldBase>(message, field)->InsertOrLookupMapValue(
+      key, val);
 }
 
 bool GeneratedMessageReflection::DeleteMapValue(
diff --git a/src/google/protobuf/generated_message_reflection.h b/src/google/protobuf/generated_message_reflection.h
index 9ef78710..15fc802c 100644
--- a/src/google/protobuf/generated_message_reflection.h
+++ b/src/google/protobuf/generated_message_reflection.h
@@ -582,7 +582,16 @@ class LIBPROTOBUF_EXPORT GeneratedMessageReflection : public Reflection {
 // which the offsets of the direct fields of a class are non-constant.
 // Fields inherited from superclasses *can* have non-constant offsets,
 // but that's not what this macro will be used for.
-//
+#if defined(__clang__)
+// For Clang we use __builtin_offsetof() and suppress the warning,
+// to avoid Control Flow Integrity and UBSan vptr sanitizers from
+// crashing while trying to validate the invalid reinterpet_casts.
+#define GOOGLE_PROTOBUF_GENERATED_MESSAGE_FIELD_OFFSET(TYPE, FIELD)    \
+  _Pragma("clang diagnostic push")                            \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"")  \
+  __builtin_offsetof(TYPE, FIELD)                             \
+  _Pragma("clang diagnostic pop")
+#else
 // Note that we calculate relative to the pointer value 16 here since if we
 // just use zero, GCC complains about dereferencing a NULL pointer.  We
 // choose 16 rather than some other number just in case the compiler would
@@ -592,6 +601,7 @@ class LIBPROTOBUF_EXPORT GeneratedMessageReflection : public Reflection {
       reinterpret_cast<const char*>(                          \
           &reinterpret_cast<const TYPE*>(16)->FIELD) -        \
       reinterpret_cast<const char*>(16))
+#endif
 
 #define PROTO2_GENERATED_DEFAULT_ONEOF_FIELD_OFFSET(ONEOF, FIELD)     \
   static_cast<int>(                                                   \
diff --git a/src/google/protobuf/generated_message_util.h b/src/google/protobuf/generated_message_util.h
index 78c8d7ff..4475556a 100644
--- a/src/google/protobuf/generated_message_util.h
+++ b/src/google/protobuf/generated_message_util.h
@@ -42,8 +42,8 @@
 #include <string>
 
 #include <google/protobuf/stubs/once.h>
-
 #include <google/protobuf/stubs/common.h>
+
 namespace google {
 
 namespace protobuf {
@@ -63,6 +63,8 @@ namespace internal {
 #undef DEPRECATED_PROTOBUF_FIELD
 #define PROTOBUF_DEPRECATED
 
+#define PROTOBUF_DEPRECATED_ATTR
+
 
 // Constants for special floating point values.
 LIBPROTOBUF_EXPORT double Infinity();
diff --git a/src/google/protobuf/io/coded_stream_unittest.cc b/src/google/protobuf/io/coded_stream_unittest.cc
index f10d4670..a8108e45 100644
--- a/src/google/protobuf/io/coded_stream_unittest.cc
+++ b/src/google/protobuf/io/coded_stream_unittest.cc
@@ -47,7 +47,6 @@
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/logging.h>
-#include <google/protobuf/stubs/scoped_ptr.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
diff --git a/src/google/protobuf/io/zero_copy_stream_impl_lite.h b/src/google/protobuf/io/zero_copy_stream_impl_lite.h
index cc7430ec..9d81ccfb 100644
--- a/src/google/protobuf/io/zero_copy_stream_impl_lite.h
+++ b/src/google/protobuf/io/zero_copy_stream_impl_lite.h
@@ -175,7 +175,7 @@ class LIBPROTOBUF_EXPORT LazyStringOutputStream : public StringOutputStream {
   int64 ByteCount() const;
 
  private:
-  const scoped_ptr<ResultCallback<string*> > callback_;
+  const google::protobuf::scoped_ptr<ResultCallback<string*> > callback_;
   bool string_is_set_;
 
   GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(LazyStringOutputStream);
diff --git a/src/google/protobuf/io/zero_copy_stream_unittest.cc b/src/google/protobuf/io/zero_copy_stream_unittest.cc
index 8c7358c1..a9db8872 100644
--- a/src/google/protobuf/io/zero_copy_stream_unittest.cc
+++ b/src/google/protobuf/io/zero_copy_stream_unittest.cc
@@ -63,8 +63,9 @@
 #endif
 #include <sstream>
 
-#include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/io/coded_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl.h>
 
 #if HAVE_ZLIB
 #include <google/protobuf/io/gzip_stream.h>
@@ -72,7 +73,6 @@
 
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
-#include <google/protobuf/stubs/scoped_ptr.h>
 #include <google/protobuf/testing/googletest.h>
 #include <google/protobuf/testing/file.h>
 #include <gtest/gtest.h>
diff --git a/src/google/protobuf/map.h b/src/google/protobuf/map.h
index 023ed971..bb0b14f9 100644
--- a/src/google/protobuf/map.h
+++ b/src/google/protobuf/map.h
@@ -614,11 +614,12 @@ class Map {
     !defined(GOOGLE_PROTOBUF_OS_EMSCRIPTEN)
     template<class NodeType, class... Args>
     void construct(NodeType* p, Args&&... args) {
-      // Clang 3.6 doesn't compile static casting to void* directly. (Issue #1266)
-      // According C++ standard 5.2.9/1: "The static_cast operator shall not cast
-      // away constness". So first the maybe const pointer is casted to const void* and
-      // after the const void* is const casted.
-      new (const_cast<void*>(static_cast<const void*>(p))) NodeType(std::forward<Args>(args)...);
+      // Clang 3.6 doesn't compile static casting to void* directly. (Issue
+      // #1266) According C++ standard 5.2.9/1: "The static_cast operator shall
+      // not cast away constness". So first the maybe const pointer is casted to
+      // const void* and after the const void* is const casted.
+      new (const_cast<void*>(static_cast<const void*>(p)))
+          NodeType(std::forward<Args>(args)...);
     }
 
     template<class NodeType>
@@ -804,6 +805,8 @@ class Map {
       // Advance through buckets, looking for the first that isn't empty.
       // If nothing non-empty is found then leave node_ == NULL.
       void SearchFrom(size_type start_bucket) {
+        GOOGLE_DCHECK(m_->index_of_first_non_null_ == m_->num_buckets_ ||
+               m_->table_[m_->index_of_first_non_null_] != NULL);
         node_ = NULL;
         for (bucket_index_ = start_bucket; bucket_index_ < m_->num_buckets_;
              bucket_index_++) {
@@ -989,7 +992,7 @@ class Map {
     void erase(iterator it) {
       GOOGLE_DCHECK_EQ(it.m_, this);
       const bool is_list = it.revalidate_if_necessary();
-      const size_type b = it.bucket_index_;
+      size_type b = it.bucket_index_;
       Node* const item = it.node_;
       if (is_list) {
         GOOGLE_DCHECK(TableEntryIsNonEmptyList(b));
@@ -1001,15 +1004,18 @@ class Map {
         Tree* tree = static_cast<Tree*>(table_[b]);
         tree->erase(it.tree_it_);
         if (tree->empty()) {
+          // Force b to be the minimum of b and b ^ 1.  This is important
+          // only because we want index_of_first_non_null_ to be correct.
+          b &= ~static_cast<size_type>(1);
           DestroyTree(tree);
-          table_[b] = table_[b ^ 1] = NULL;
+          table_[b] = table_[b + 1] = NULL;
         }
       }
       DestroyNode(item);
       --num_elements_;
       if (GOOGLE_PREDICT_FALSE(b == index_of_first_non_null_)) {
         while (index_of_first_non_null_ < num_buckets_ &&
-               table_[index_of_first_non_null_] == 0) {
+               table_[index_of_first_non_null_] == NULL) {
           ++index_of_first_non_null_;
         }
       }
@@ -1045,6 +1051,8 @@ class Map {
     // Requires count(*KeyPtrFromNodePtr(node)) == 0 and that b is the correct
     // bucket.  num_elements_ is not modified.
     iterator InsertUnique(size_type b, Node* node) {
+      GOOGLE_DCHECK(index_of_first_non_null_ == num_buckets_ ||
+             table_[index_of_first_non_null_] != NULL);
       // In practice, the code that led to this point may have already
       // determined whether we are inserting into an empty list, a short list,
       // or whatever.  But it's probably cheap enough to recompute that here;
@@ -1057,11 +1065,16 @@ class Map {
         if (GOOGLE_PREDICT_FALSE(TableEntryIsTooLong(b))) {
           TreeConvert(b);
           result = InsertUniqueInTree(b, node);
+          GOOGLE_DCHECK_EQ(result.bucket_index_, b & ~static_cast<size_type>(1));
         } else {
-          result = InsertUniqueInList(b, node);
+          // Insert into a pre-existing list.  This case cannot modify
+          // index_of_first_non_null_, so we skip the code to update it.
+          return InsertUniqueInList(b, node);
         }
       } else {
-        result = InsertUniqueInTree(b, node);
+        // Insert into a pre-existing tree.  This case cannot modify
+        // index_of_first_non_null_, so we skip the code to update it.
+        return InsertUniqueInTree(b, node);
       }
       index_of_first_non_null_ =
           std::min(index_of_first_non_null_, result.bucket_index_);
@@ -1137,7 +1150,7 @@ class Map {
       num_buckets_ = new_num_buckets;
       table_ = CreateEmptyTable(num_buckets_);
       const size_type start = index_of_first_non_null_;
-      index_of_first_non_null_ = 0;
+      index_of_first_non_null_ = num_buckets_;
       for (size_type i = start; i < old_table_size; i++) {
         if (TableEntryIsNonEmptyList(old_table, i)) {
           TransferList(old_table, i);
@@ -1189,10 +1202,10 @@ class Map {
       return TableEntryIsList(table_, b);
     }
     static bool TableEntryIsEmpty(void* const* table, size_type b) {
-      return table[b] == 0;
+      return table[b] == NULL;
     }
     static bool TableEntryIsNonEmptyList(void* const* table, size_type b) {
-      return table[b] != 0 && table[b] != table[b ^ 1];
+      return table[b] != NULL && table[b] != table[b ^ 1];
     }
     static bool TableEntryIsTree(void* const* table, size_type b) {
       return !TableEntryIsEmpty(table, b) &&
@@ -1250,7 +1263,7 @@ class Map {
 
     size_type BucketNumber(const Key& k) const {
       // We inherit from hasher, so one-arg operator() provides a hash function.
-      size_type h = (*this)(k);
+      size_type h = (*const_cast<InnerMap*>(this))(k);
       // To help prevent people from making assumptions about the hash function,
       // we use the seed differently depending on NDEBUG.  The default hash
       // function, the seeding, etc., are all likely to change in the future.
diff --git a/src/google/protobuf/map_field.cc b/src/google/protobuf/map_field.cc
index eddc95c4..49f91818 100644
--- a/src/google/protobuf/map_field.cc
+++ b/src/google/protobuf/map_field.cc
@@ -178,18 +178,19 @@ bool DynamicMapField::ContainsMapKey(
   return iter != map.end();
 }
 
-bool DynamicMapField::InsertMapValue(
+bool DynamicMapField::InsertOrLookupMapValue(
     const MapKey& map_key, MapValueRef* val) {
-  bool result = false;
-
-  MapValueRef& map_val = (*MutableMap())[map_key];
-  // If map_val.data_ is not set, it is newly inserted by map_[map_key].
-  if (map_val.data_ == NULL) {
-    result = true;
+  // Always use mutable map because users may change the map value by
+  // MapValueRef.
+  Map<MapKey, MapValueRef>* map = MutableMap();
+  Map<MapKey, MapValueRef>::iterator iter = map->find(map_key);
+  if (iter == map->end()) {
+    // Insert
+    MapValueRef& map_val = (*map)[map_key];
     const FieldDescriptor* val_des =
         default_entry_->GetDescriptor()->FindFieldByName("value");
     map_val.SetType(val_des->cpp_type());
-    // Allocate momery for the inserted MapValueRef, and initialize to
+    // Allocate memory for the inserted MapValueRef, and initialize to
     // default value.
     switch (val_des->cpp_type()) {
 #define HANDLE_TYPE(CPPTYPE, TYPE)                              \
@@ -216,9 +217,13 @@ bool DynamicMapField::InsertMapValue(
         break;
       }
     }
+    val->CopyFrom(map_val);
+    return true;
   }
-  val->CopyFrom(map_val);
-  return result;
+  // map_key is already in the map. Make sure (*map)[map_key] is not called.
+  // [] may reorder the map and iterators.
+  val->CopyFrom(iter->second);
+  return false;
 }
 
 bool DynamicMapField::DeleteMapValue(const MapKey& map_key) {
diff --git a/src/google/protobuf/map_field.h b/src/google/protobuf/map_field.h
index 9130166b..4b46f3aa 100644
--- a/src/google/protobuf/map_field.h
+++ b/src/google/protobuf/map_field.h
@@ -87,7 +87,8 @@ class LIBPROTOBUF_EXPORT MapFieldBase {
 
   // Pure virtual map APIs for Map Reflection.
   virtual bool ContainsMapKey(const MapKey& map_key) const = 0;
-  virtual bool InsertMapValue(const MapKey& map_key, MapValueRef* val) = 0;
+  virtual bool InsertOrLookupMapValue(
+      const MapKey& map_key, MapValueRef* val) = 0;
   virtual bool DeleteMapValue(const MapKey& map_key) = 0;
   virtual bool EqualIterator(const MapIterator& a,
                              const MapIterator& b) const = 0;
@@ -251,7 +252,7 @@ class MapField : public TypeDefinedMapFieldBase<Key, T>,
 
   // Implement MapFieldBase
   bool ContainsMapKey(const MapKey& map_key) const;
-  bool InsertMapValue(const MapKey& map_key, MapValueRef* val);
+  bool InsertOrLookupMapValue(const MapKey& map_key, MapValueRef* val);
   bool DeleteMapValue(const MapKey& map_key);
 
   // Accessors
@@ -302,7 +303,7 @@ class LIBPROTOBUF_EXPORT DynamicMapField: public TypeDefinedMapFieldBase<MapKey,
 
   // Implement MapFieldBase
   bool ContainsMapKey(const MapKey& map_key) const;
-  bool InsertMapValue(const MapKey& map_key, MapValueRef* val);
+  bool InsertOrLookupMapValue(const MapKey& map_key, MapValueRef* val);
   bool DeleteMapValue(const MapKey& map_key);
 
   const Map<MapKey, MapValueRef>& GetMap() const;
diff --git a/src/google/protobuf/map_field_inl.h b/src/google/protobuf/map_field_inl.h
index f116697c..01c9b89a 100644
--- a/src/google/protobuf/map_field_inl.h
+++ b/src/google/protobuf/map_field_inl.h
@@ -262,16 +262,22 @@ template <typename Key, typename T,
           WireFormatLite::FieldType kValueFieldType,
           int default_enum_value>
 bool MapField<Key, T, kKeyFieldType, kValueFieldType,
-              default_enum_value>::InsertMapValue(const MapKey& map_key,
-                                                  MapValueRef* val) {
+              default_enum_value>::InsertOrLookupMapValue(
+                  const MapKey& map_key,
+                  MapValueRef* val) {
+  // Always use mutable map because users may change the map value by
+  // MapValueRef.
   Map<Key, T>* map = MutableMap();
-  bool result = false;
   const Key& key = UnwrapMapKey<Key>(map_key);
-  if (map->end() == map->find(key)) {
-    result = true;
+  typename Map<Key, T>::iterator iter = map->find(key);
+  if (map->end() == iter) {
+    val->SetValue(&((*map)[key]));
+    return true;
   }
-  val->SetValue(&((*map)[key]));
-  return result;
+  // Key is already in the map. Make sure (*map)[key] is not called.
+  // [] may reorder the map and iterators.
+  val->SetValue(&(iter->second));
+  return false;
 }
 
 template <typename Key, typename T,
diff --git a/src/google/protobuf/map_field_test.cc b/src/google/protobuf/map_field_test.cc
index 2ff1d6bb..223d42f3 100644
--- a/src/google/protobuf/map_field_test.cc
+++ b/src/google/protobuf/map_field_test.cc
@@ -78,7 +78,7 @@ class MapFieldBaseStub : public MapFieldBase {
   bool ContainsMapKey(const MapKey& map_key) const {
     return false;
   }
-  bool InsertMapValue(const MapKey& map_key, MapValueRef* val) {
+  bool InsertOrLookupMapValue(const MapKey& map_key, MapValueRef* val) {
     return false;
   }
   bool DeleteMapValue(const MapKey& map_key) {
diff --git a/src/google/protobuf/map_test.cc b/src/google/protobuf/map_test.cc
index e833699a..9d4d6c13 100644
--- a/src/google/protobuf/map_test.cc
+++ b/src/google/protobuf/map_test.cc
@@ -307,6 +307,11 @@ static int64 Now() {
       google::protobuf::util::TimeUtil::GetCurrentTime());
 }
 
+// Arbitrary odd integers for creating test data.
+static int k0 = 812398771;
+static int k1 = 1312938717;
+static int k2 = 1321555333;
+
 // A naive begin() implementation will cause begin() to get slower and slower
 // if one erases elements at the "front" of the hash map, and we'd like to
 // avoid that, as std::unordered_map does.
@@ -315,8 +320,18 @@ TEST_P(MapImplTest, BeginIsFast) {
   if (/*GetParam()*/true) return;
   Map<int32, int32> map(false);  // This test uses new-style maps only.
   const int kTestSize = 250000;
-  for (int i = 0; i < kTestSize; i++) {
-    map[i] = i;
+  // Create a random-looking map of size n.  Use non-negative integer keys.
+  uint32 frog = 123983;
+  int last_key = 0;
+  int counter = 0;
+  while (map.size() < kTestSize) {
+    frog *= static_cast<uint32>(k0);
+    frog ^= frog >> 17;
+    frog += counter++;
+    last_key =
+        static_cast<int>(frog) >= 0 ? static_cast<int>(frog) : last_key ^ 1;
+    GOOGLE_DCHECK_GE(last_key, 0);
+    map[last_key] = last_key ^ 1;
   }
   vector<int64> times;
   // We're going to do map.erase(map.begin()) over and over again.  But,
@@ -384,11 +399,6 @@ TEST_P(MapImplTest, HashFlood) {
   EXPECT_LE(x1, x0 * 20);
 }
 
-// Arbitrary odd integers for creating test data.
-static int k0 = 812398771;
-static int k1 = 1312938717;
-static int k2 = 1321555333;
-
 template <typename T, typename U>
 static void TestValidityForAllKeysExcept(int key_to_avoid,
                                          const T& check_map,
diff --git a/src/google/protobuf/message_lite.cc b/src/google/protobuf/message_lite.cc
index fe124c45..9d7b64f7 100644
--- a/src/google/protobuf/message_lite.cc
+++ b/src/google/protobuf/message_lite.cc
@@ -361,6 +361,11 @@ void GenericTypeHandler<MessageLite>::Merge(const MessageLite& from,
                                             MessageLite* to) {
   to->CheckTypeAndMergeFrom(from);
 }
+template<>
+void GenericTypeHandler<string>::Merge(const string& from,
+                                              string* to) {
+  *to = from;
+}
 }  // namespace internal
 
 }  // namespace protobuf
diff --git a/src/google/protobuf/proto3_arena_lite_unittest.cc b/src/google/protobuf/proto3_arena_lite_unittest.cc
new file mode 100644
index 00000000..0f18c027
--- /dev/null
+++ b/src/google/protobuf/proto3_arena_lite_unittest.cc
@@ -0,0 +1,164 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <string>
+#include <memory>
+#ifndef _SHARED_PTR_H
+#include <google/protobuf/stubs/shared_ptr.h>
+#endif
+#include <vector>
+
+#include <google/protobuf/test_util.h>
+#include <google/protobuf/unittest.pb.h>
+#include <google/protobuf/unittest_proto3_arena_lite.pb.h>
+#include <google/protobuf/arena.h>
+#include <google/protobuf/testing/googletest.h>
+#include <gtest/gtest.h>
+
+namespace google {
+using proto3_arena_lite_unittest::TestAllTypes;
+
+namespace protobuf {
+namespace {
+// We selectively set/check a few representative fields rather than all fields
+// as this test is only expected to cover the basics of arena support.
+void SetAllFields(TestAllTypes* m) {
+  m->set_optional_int32(100);
+  m->set_optional_string("asdf");
+  m->set_optional_bytes("jkl;");
+  m->mutable_optional_nested_message()->set_bb(42);
+  m->mutable_optional_foreign_message()->set_c(43);
+  m->set_optional_nested_enum(
+      proto3_arena_lite_unittest::TestAllTypes_NestedEnum_BAZ);
+  m->set_optional_foreign_enum(
+      proto3_arena_lite_unittest::FOREIGN_BAZ);
+  m->mutable_optional_lazy_message()->set_bb(45);
+  m->add_repeated_int32(100);
+  m->add_repeated_string("asdf");
+  m->add_repeated_bytes("jkl;");
+  m->add_repeated_nested_message()->set_bb(46);
+  m->add_repeated_foreign_message()->set_c(47);
+  m->add_repeated_nested_enum(
+      proto3_arena_lite_unittest::TestAllTypes_NestedEnum_BAZ);
+  m->add_repeated_foreign_enum(
+      proto3_arena_lite_unittest::FOREIGN_BAZ);
+  m->add_repeated_lazy_message()->set_bb(49);
+
+  m->set_oneof_uint32(1);
+  m->mutable_oneof_nested_message()->set_bb(50);
+  m->set_oneof_string("test");  // only this one remains set
+}
+
+void ExpectAllFieldsSet(const TestAllTypes& m) {
+  EXPECT_EQ(100, m.optional_int32());
+  EXPECT_EQ("asdf", m.optional_string());
+  EXPECT_EQ("jkl;", m.optional_bytes());
+  EXPECT_EQ(true, m.has_optional_nested_message());
+  EXPECT_EQ(42, m.optional_nested_message().bb());
+  EXPECT_EQ(true, m.has_optional_foreign_message());
+  EXPECT_EQ(43, m.optional_foreign_message().c());
+  EXPECT_EQ(proto3_arena_lite_unittest::TestAllTypes_NestedEnum_BAZ,
+            m.optional_nested_enum());
+  EXPECT_EQ(proto3_arena_lite_unittest::FOREIGN_BAZ,
+            m.optional_foreign_enum());
+  EXPECT_EQ(true, m.has_optional_lazy_message());
+  EXPECT_EQ(45, m.optional_lazy_message().bb());
+
+  EXPECT_EQ(1, m.repeated_int32_size());
+  EXPECT_EQ(100, m.repeated_int32(0));
+  EXPECT_EQ(1, m.repeated_string_size());
+  EXPECT_EQ("asdf", m.repeated_string(0));
+  EXPECT_EQ(1, m.repeated_bytes_size());
+  EXPECT_EQ("jkl;", m.repeated_bytes(0));
+  EXPECT_EQ(1, m.repeated_nested_message_size());
+  EXPECT_EQ(46, m.repeated_nested_message(0).bb());
+  EXPECT_EQ(1, m.repeated_foreign_message_size());
+  EXPECT_EQ(47, m.repeated_foreign_message(0).c());
+  EXPECT_EQ(1, m.repeated_nested_enum_size());
+  EXPECT_EQ(proto3_arena_lite_unittest::TestAllTypes_NestedEnum_BAZ,
+            m.repeated_nested_enum(0));
+  EXPECT_EQ(1, m.repeated_foreign_enum_size());
+  EXPECT_EQ(proto3_arena_lite_unittest::FOREIGN_BAZ,
+            m.repeated_foreign_enum(0));
+  EXPECT_EQ(1, m.repeated_lazy_message_size());
+  EXPECT_EQ(49, m.repeated_lazy_message(0).bb());
+
+  EXPECT_EQ(proto3_arena_lite_unittest::TestAllTypes::kOneofString,
+            m.oneof_field_case());
+  EXPECT_EQ("test", m.oneof_string());
+}
+
+// In this file we only test some basic functionalities of arena support in
+// proto3 and expect the arena support to be fully tested in proto2 unittests
+// because proto3 shares most code with proto2.
+
+TEST(Proto3ArenaLiteTest, Parsing) {
+  TestAllTypes original;
+  SetAllFields(&original);
+
+  Arena arena;
+  TestAllTypes* arena_message = Arena::CreateMessage<TestAllTypes>(&arena);
+  arena_message->ParseFromString(original.SerializeAsString());
+  ExpectAllFieldsSet(*arena_message);
+}
+
+TEST(Proto3ArenaLiteTest, Swap) {
+  Arena arena1;
+  Arena arena2;
+
+  // Test Swap().
+  TestAllTypes* arena1_message = Arena::CreateMessage<TestAllTypes>(&arena1);
+  TestAllTypes* arena2_message = Arena::CreateMessage<TestAllTypes>(&arena2);
+  arena1_message->Swap(arena2_message);
+  EXPECT_EQ(&arena1, arena1_message->GetArena());
+  EXPECT_EQ(&arena2, arena2_message->GetArena());
+}
+
+TEST(Proto3ArenaLiteTest, SetAllocatedMessage) {
+  Arena arena;
+  TestAllTypes *arena_message = Arena::CreateMessage<TestAllTypes>(&arena);
+  TestAllTypes::NestedMessage* nested = new TestAllTypes::NestedMessage;
+  nested->set_bb(118);
+  arena_message->set_allocated_optional_nested_message(nested);
+  EXPECT_EQ(118, arena_message->optional_nested_message().bb());
+}
+
+TEST(Proto3ArenaLiteTest, ReleaseMessage) {
+  Arena arena;
+  TestAllTypes* arena_message = Arena::CreateMessage<TestAllTypes>(&arena);
+  arena_message->mutable_optional_nested_message()->set_bb(118);
+  google::protobuf::scoped_ptr<TestAllTypes::NestedMessage> nested(
+      arena_message->release_optional_nested_message());
+  EXPECT_EQ(118, nested->bb());
+}
+
+}  // namespace
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/proto3_lite_unittest.cc b/src/google/protobuf/proto3_lite_unittest.cc
new file mode 100644
index 00000000..2e2beea9
--- /dev/null
+++ b/src/google/protobuf/proto3_lite_unittest.cc
@@ -0,0 +1,145 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <string>
+#include <memory>
+#ifndef _SHARED_PTR_H
+#include <google/protobuf/stubs/shared_ptr.h>
+#endif
+#include <vector>
+
+#include <google/protobuf/test_util.h>
+#include <google/protobuf/unittest.pb.h>
+#include <google/protobuf/unittest_proto3_lite.pb.h>
+#include <google/protobuf/arena.h>
+#include <google/protobuf/testing/googletest.h>
+#include <gtest/gtest.h>
+
+namespace google {
+using proto3_lite_unittest::TestAllTypes;
+
+namespace protobuf {
+namespace {
+// We selectively set/check a few representative fields rather than all fields
+// as this test is only expected to cover the basics of lite support.
+void SetAllFields(TestAllTypes* m) {
+  m->set_optional_int32(100);
+  m->set_optional_string("asdf");
+  m->set_optional_bytes("jkl;");
+  m->mutable_optional_nested_message()->set_bb(42);
+  m->mutable_optional_foreign_message()->set_c(43);
+  m->set_optional_nested_enum(
+      proto3_lite_unittest::TestAllTypes_NestedEnum_BAZ);
+  m->set_optional_foreign_enum(
+      proto3_lite_unittest::FOREIGN_BAZ);
+  m->mutable_optional_lazy_message()->set_bb(45);
+  m->add_repeated_int32(100);
+  m->add_repeated_string("asdf");
+  m->add_repeated_bytes("jkl;");
+  m->add_repeated_nested_message()->set_bb(46);
+  m->add_repeated_foreign_message()->set_c(47);
+  m->add_repeated_nested_enum(
+      proto3_lite_unittest::TestAllTypes_NestedEnum_BAZ);
+  m->add_repeated_foreign_enum(
+      proto3_lite_unittest::FOREIGN_BAZ);
+  m->add_repeated_lazy_message()->set_bb(49);
+
+  m->set_oneof_uint32(1);
+  m->mutable_oneof_nested_message()->set_bb(50);
+  m->set_oneof_string("test");  // only this one remains set
+}
+
+void ExpectAllFieldsSet(const TestAllTypes& m) {
+  EXPECT_EQ(100, m.optional_int32());
+  EXPECT_EQ("asdf", m.optional_string());
+  EXPECT_EQ("jkl;", m.optional_bytes());
+  EXPECT_EQ(true, m.has_optional_nested_message());
+  EXPECT_EQ(42, m.optional_nested_message().bb());
+  EXPECT_EQ(true, m.has_optional_foreign_message());
+  EXPECT_EQ(43, m.optional_foreign_message().c());
+  EXPECT_EQ(proto3_lite_unittest::TestAllTypes_NestedEnum_BAZ,
+            m.optional_nested_enum());
+  EXPECT_EQ(proto3_lite_unittest::FOREIGN_BAZ,
+            m.optional_foreign_enum());
+  EXPECT_EQ(true, m.has_optional_lazy_message());
+  EXPECT_EQ(45, m.optional_lazy_message().bb());
+
+  EXPECT_EQ(1, m.repeated_int32_size());
+  EXPECT_EQ(100, m.repeated_int32(0));
+  EXPECT_EQ(1, m.repeated_string_size());
+  EXPECT_EQ("asdf", m.repeated_string(0));
+  EXPECT_EQ(1, m.repeated_bytes_size());
+  EXPECT_EQ("jkl;", m.repeated_bytes(0));
+  EXPECT_EQ(1, m.repeated_nested_message_size());
+  EXPECT_EQ(46, m.repeated_nested_message(0).bb());
+  EXPECT_EQ(1, m.repeated_foreign_message_size());
+  EXPECT_EQ(47, m.repeated_foreign_message(0).c());
+  EXPECT_EQ(1, m.repeated_nested_enum_size());
+  EXPECT_EQ(proto3_lite_unittest::TestAllTypes_NestedEnum_BAZ,
+            m.repeated_nested_enum(0));
+  EXPECT_EQ(1, m.repeated_foreign_enum_size());
+  EXPECT_EQ(proto3_lite_unittest::FOREIGN_BAZ,
+            m.repeated_foreign_enum(0));
+  EXPECT_EQ(1, m.repeated_lazy_message_size());
+  EXPECT_EQ(49, m.repeated_lazy_message(0).bb());
+
+  EXPECT_EQ(proto3_lite_unittest::TestAllTypes::kOneofString,
+            m.oneof_field_case());
+  EXPECT_EQ("test", m.oneof_string());
+}
+
+// In this file we only test some basic functionalities of in proto3 and expect
+// the rest is fully tested in proto2 unittests because proto3 shares most code
+// with proto2.
+
+TEST(Proto3LiteTest, Parsing) {
+  TestAllTypes original;
+  SetAllFields(&original);
+
+  TestAllTypes msg;
+  msg.ParseFromString(original.SerializeAsString());
+  ExpectAllFieldsSet(msg);
+}
+
+TEST(Proto3LiteTest, Swap) {
+  // Test Swap().
+  TestAllTypes msg1;
+  TestAllTypes msg2;
+  msg1.set_optional_string("123");
+  msg2.set_optional_string("3456");
+  msg1.Swap(&msg2);
+  EXPECT_EQ("3456", msg1.optional_string());
+  EXPECT_EQ("123", msg2.optional_string());
+  EXPECT_EQ(msg1.ByteSize(), msg2.ByteSize() + 1);
+}
+
+}  // namespace
+}  // namespace protobuf
+}  // namespace google
diff --git a/src/google/protobuf/repeated_field.h b/src/google/protobuf/repeated_field.h
index deeb7d50..1961bc48 100644
--- a/src/google/protobuf/repeated_field.h
+++ b/src/google/protobuf/repeated_field.h
@@ -626,6 +626,13 @@ inline void* GenericTypeHandler<MessageLite>::GetMaybeArenaPointer(
 template <>
 void GenericTypeHandler<MessageLite>::Merge(const MessageLite& from,
                                             MessageLite* to);
+template<>
+inline void GenericTypeHandler<string>::Clear(string* value) {
+  value->clear();
+}
+template<>
+void GenericTypeHandler<string>::Merge(const string& from,
+                                       string* to);
 
 // Declarations of the specialization as we cannot define them here, as the
 // header that defines ProtocolMessage depends on types defined in this header.
diff --git a/src/google/protobuf/source_context.pb.cc b/src/google/protobuf/source_context.pb.cc
index f2eb7ae7..c67cd102 100644
--- a/src/google/protobuf/source_context.pb.cc
+++ b/src/google/protobuf/source_context.pb.cc
@@ -177,12 +177,13 @@ SourceContext* SourceContext::New(::google::protobuf::Arena* arena) const {
 }
 
 void SourceContext::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.SourceContext)
   file_name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 
 bool SourceContext::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.SourceContext)
   for (;;) {
@@ -262,6 +263,7 @@ void SourceContext::SerializeWithCachedSizes(
 }
 
 int SourceContext::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.SourceContext)
   int total_size = 0;
 
   // optional string file_name = 1;
@@ -278,18 +280,22 @@ int SourceContext::ByteSize() const {
 }
 
 void SourceContext::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.SourceContext)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const SourceContext* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const SourceContext>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.SourceContext)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.SourceContext)
     MergeFrom(*source);
   }
 }
 
 void SourceContext::MergeFrom(const SourceContext& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.SourceContext)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.file_name().size() > 0) {
 
@@ -298,12 +304,14 @@ void SourceContext::MergeFrom(const SourceContext& from) {
 }
 
 void SourceContext::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.SourceContext)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void SourceContext::CopyFrom(const SourceContext& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.SourceContext)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -365,6 +373,7 @@ void SourceContext::clear_file_name() {
   return file_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* SourceContext::release_file_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceContext.file_name)
   
   return file_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/source_context.pb.h b/src/google/protobuf/source_context.pb.h
index 02e11460..ccfd365b 100644
--- a/src/google/protobuf/source_context.pb.h
+++ b/src/google/protobuf/source_context.pb.h
@@ -160,6 +160,7 @@ inline ::std::string* SourceContext::mutable_file_name() {
   return file_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* SourceContext::release_file_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.SourceContext.file_name)
   
   return file_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
diff --git a/src/google/protobuf/struct.pb.cc b/src/google/protobuf/struct.pb.cc
index 9e5b086b..11ccabbf 100644
--- a/src/google/protobuf/struct.pb.cc
+++ b/src/google/protobuf/struct.pb.cc
@@ -282,12 +282,13 @@ Struct* Struct::New(::google::protobuf::Arena* arena) const {
 }
 
 void Struct::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Struct)
   fields_.Clear();
 }
 
 bool Struct::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Struct)
   for (;;) {
@@ -385,6 +386,7 @@ void Struct::SerializeWithCachedSizes(
 }
 
 int Struct::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Struct)
   int total_size = 0;
 
   // map<string, .google.protobuf.Value> fields = 1;
@@ -407,29 +409,35 @@ int Struct::ByteSize() const {
 }
 
 void Struct::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Struct)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Struct* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Struct>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Struct)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Struct)
     MergeFrom(*source);
   }
 }
 
 void Struct::MergeFrom(const Struct& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Struct)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   fields_.MergeFrom(from.fields_);
 }
 
 void Struct::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Struct)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Struct::CopyFrom(const Struct& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Struct)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -562,6 +570,7 @@ Value* Value::New(::google::protobuf::Arena* arena) const {
 }
 
 void Value::clear_kind() {
+// @@protoc_insertion_point(one_of_clear_start:google.protobuf.Value)
   switch(kind_case()) {
     case kNullValue: {
       // No need to clear
@@ -596,12 +605,13 @@ void Value::clear_kind() {
 
 
 void Value::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Value)
   clear_kind();
 }
 
 bool Value::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Value)
   for (;;) {
@@ -813,6 +823,7 @@ void Value::SerializeWithCachedSizes(
 }
 
 int Value::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Value)
   int total_size = 0;
 
   switch (kind_case()) {
@@ -864,18 +875,22 @@ int Value::ByteSize() const {
 }
 
 void Value::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Value* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Value>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Value)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Value)
     MergeFrom(*source);
   }
 }
 
 void Value::MergeFrom(const Value& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   switch (from.kind_case()) {
     case kNullValue: {
@@ -909,12 +924,14 @@ void Value::MergeFrom(const Value& from) {
 }
 
 void Value::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Value::CopyFrom(const Value& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1065,6 +1082,7 @@ void Value::clear_string_value() {
   return kind_.string_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Value::release_string_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.string_value)
   if (has_string_value()) {
     clear_has_kind();
     return kind_.string_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -1143,6 +1161,7 @@ void Value::clear_struct_value() {
   return kind_.struct_value_;
 }
 ::google::protobuf::Struct* Value::release_struct_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.struct_value)
   if (has_struct_value()) {
     clear_has_kind();
     ::google::protobuf::Struct* temp = kind_.struct_value_;
@@ -1190,6 +1209,7 @@ void Value::clear_list_value() {
   return kind_.list_value_;
 }
 ::google::protobuf::ListValue* Value::release_list_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.list_value)
   if (has_list_value()) {
     clear_has_kind();
     ::google::protobuf::ListValue* temp = kind_.list_value_;
@@ -1284,12 +1304,13 @@ ListValue* ListValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void ListValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.ListValue)
   values_.Clear();
 }
 
 bool ListValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.ListValue)
   for (;;) {
@@ -1361,6 +1382,7 @@ void ListValue::SerializeWithCachedSizes(
 }
 
 int ListValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.ListValue)
   int total_size = 0;
 
   // repeated .google.protobuf.Value values = 1;
@@ -1378,29 +1400,35 @@ int ListValue::ByteSize() const {
 }
 
 void ListValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.ListValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const ListValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const ListValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.ListValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.ListValue)
     MergeFrom(*source);
   }
 }
 
 void ListValue::MergeFrom(const ListValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.ListValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   values_.MergeFrom(from.values_);
 }
 
 void ListValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.ListValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void ListValue::CopyFrom(const ListValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.ListValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
diff --git a/src/google/protobuf/struct.pb.h b/src/google/protobuf/struct.pb.h
index 0527c812..6a4764a7 100644
--- a/src/google/protobuf/struct.pb.h
+++ b/src/google/protobuf/struct.pb.h
@@ -550,6 +550,7 @@ inline ::std::string* Value::mutable_string_value() {
   return kind_.string_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Value::release_string_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.string_value)
   if (has_string_value()) {
     clear_has_kind();
     return kind_.string_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
@@ -628,6 +629,7 @@ inline ::google::protobuf::Struct* Value::mutable_struct_value() {
   return kind_.struct_value_;
 }
 inline ::google::protobuf::Struct* Value::release_struct_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.struct_value)
   if (has_struct_value()) {
     clear_has_kind();
     ::google::protobuf::Struct* temp = kind_.struct_value_;
@@ -675,6 +677,7 @@ inline ::google::protobuf::ListValue* Value::mutable_list_value() {
   return kind_.list_value_;
 }
 inline ::google::protobuf::ListValue* Value::release_list_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Value.list_value)
   if (has_list_value()) {
     clear_has_kind();
     ::google::protobuf::ListValue* temp = kind_.list_value_;
diff --git a/src/google/protobuf/stubs/stringprintf.cc b/src/google/protobuf/stubs/stringprintf.cc
index 3272d8e3..83fdfe45 100644
--- a/src/google/protobuf/stubs/stringprintf.cc
+++ b/src/google/protobuf/stubs/stringprintf.cc
@@ -37,7 +37,6 @@
 #include <stdio.h> // MSVC requires this for _vsnprintf
 #include <vector>
 #include <google/protobuf/stubs/common.h>
-#include <google/protobuf/testing/googletest.h>
 
 namespace google {
 namespace protobuf {
diff --git a/src/google/protobuf/text_format.cc b/src/google/protobuf/text_format.cc
index 1ed74391..c0dfd53f 100644
--- a/src/google/protobuf/text_format.cc
+++ b/src/google/protobuf/text_format.cc
@@ -1785,14 +1785,12 @@ void TextFormat::Printer::PrintFieldValue(
           ? reflection->GetRepeatedStringReference(
               message, field, index, &scratch)
           : reflection->GetStringReference(message, field, &scratch);
-      int64 size = value.size();
-      if (truncate_string_field_longer_than_ > 0) {
-        size = std::min(truncate_string_field_longer_than_,
-                        static_cast<int64>(value.size()));
-      }
-      string truncated_value(value.substr(0, size) + "...<truncated>...");
       const string* value_to_print = &value;
-      if (size < value.size()) {
+      string truncated_value;
+      if (truncate_string_field_longer_than_ > 0 &&
+          truncate_string_field_longer_than_ < value.size()) {
+        truncated_value = value.substr(0, truncate_string_field_longer_than_) +
+                          "...<truncated>...";
         value_to_print = &truncated_value;
       }
       if (field->type() == FieldDescriptor::TYPE_STRING) {
diff --git a/src/google/protobuf/text_format_unittest.cc b/src/google/protobuf/text_format_unittest.cc
index f97658fd..58aa3f8d 100644
--- a/src/google/protobuf/text_format_unittest.cc
+++ b/src/google/protobuf/text_format_unittest.cc
@@ -46,6 +46,7 @@
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/testing/file.h>
+#include <google/protobuf/testing/file.h>
 #include <google/protobuf/test_util.h>
 #include <google/protobuf/unittest.pb.h>
 #include <google/protobuf/unittest_mset.pb.h>
@@ -53,10 +54,10 @@
 #include <google/protobuf/io/tokenizer.h>
 #include <google/protobuf/io/zero_copy_stream_impl.h>
 #include <google/protobuf/stubs/strutil.h>
-#include <google/protobuf/stubs/mathlimits.h>
 #include <google/protobuf/stubs/substitute.h>
 #include <google/protobuf/testing/googletest.h>
 #include <gtest/gtest.h>
+#include <google/protobuf/stubs/mathlimits.h>
 
 
 namespace google {
diff --git a/src/google/protobuf/timestamp.pb.cc b/src/google/protobuf/timestamp.pb.cc
index 1393cc95..7cdf5093 100644
--- a/src/google/protobuf/timestamp.pb.cc
+++ b/src/google/protobuf/timestamp.pb.cc
@@ -193,8 +193,17 @@ Timestamp* Timestamp::New(::google::protobuf::Arena* arena) const {
 }
 
 void Timestamp::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Timestamp)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(Timestamp, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<Timestamp*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -210,7 +219,7 @@ void Timestamp::Clear() {
 
 bool Timestamp::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Timestamp)
   for (;;) {
@@ -302,6 +311,7 @@ void Timestamp::SerializeWithCachedSizes(
 }
 
 int Timestamp::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Timestamp)
   int total_size = 0;
 
   // optional int64 seconds = 1;
@@ -325,18 +335,22 @@ int Timestamp::ByteSize() const {
 }
 
 void Timestamp::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Timestamp)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Timestamp* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Timestamp>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Timestamp)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Timestamp)
     MergeFrom(*source);
   }
 }
 
 void Timestamp::MergeFrom(const Timestamp& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Timestamp)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.seconds() != 0) {
     set_seconds(from.seconds());
@@ -347,12 +361,14 @@ void Timestamp::MergeFrom(const Timestamp& from) {
 }
 
 void Timestamp::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Timestamp)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Timestamp::CopyFrom(const Timestamp& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Timestamp)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
diff --git a/src/google/protobuf/type.pb.cc b/src/google/protobuf/type.pb.cc
index 7b47b3bd..759cab27 100644
--- a/src/google/protobuf/type.pb.cc
+++ b/src/google/protobuf/type.pb.cc
@@ -359,6 +359,7 @@ Type* Type::New(::google::protobuf::Arena* arena) const {
 }
 
 void Type::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Type)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   if (GetArenaNoVirtual() == NULL && source_context_ != NULL) delete source_context_;
   source_context_ = NULL;
@@ -370,7 +371,7 @@ void Type::Clear() {
 
 bool Type::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Type)
   for (;;) {
@@ -603,6 +604,7 @@ void Type::SerializeWithCachedSizes(
 }
 
 int Type::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Type)
   int total_size = 0;
 
   // optional string name = 1;
@@ -655,18 +657,22 @@ int Type::ByteSize() const {
 }
 
 void Type::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Type)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Type* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Type>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Type)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Type)
     MergeFrom(*source);
   }
 }
 
 void Type::MergeFrom(const Type& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Type)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   fields_.MergeFrom(from.fields_);
   oneofs_.MergeFrom(from.oneofs_);
@@ -684,12 +690,14 @@ void Type::MergeFrom(const Type& from) {
 }
 
 void Type::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Type)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Type::CopyFrom(const Type& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Type)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -756,6 +764,7 @@ void Type::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Type::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Type.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -828,6 +837,7 @@ void Type::clear_oneofs() {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.Type.oneofs)
 }
  ::std::string* Type::add_oneofs() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.Type.oneofs)
   return oneofs_.Add();
 }
  void Type::add_oneofs(const ::std::string& value) {
@@ -904,6 +914,7 @@ const ::google::protobuf::SourceContext& Type::source_context() const {
   return source_context_;
 }
 ::google::protobuf::SourceContext* Type::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Type.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -1104,8 +1115,17 @@ Field* Field::New(::google::protobuf::Arena* arena) const {
 }
 
 void Field::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Field)
+#if defined(__clang__)
+#define ZR_HELPER_(f) \
+  _Pragma("clang diagnostic push") \
+  _Pragma("clang diagnostic ignored \"-Winvalid-offsetof\"") \
+  __builtin_offsetof(Field, f) \
+  _Pragma("clang diagnostic pop")
+#else
 #define ZR_HELPER_(f) reinterpret_cast<char*>(\
   &reinterpret_cast<Field*>(16)->f)
+#endif
 
 #define ZR_(first, last) do {\
   ::memset(&first, 0,\
@@ -1128,7 +1148,7 @@ void Field::Clear() {
 
 bool Field::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Field)
   for (;;) {
@@ -1483,6 +1503,7 @@ void Field::SerializeWithCachedSizes(
 }
 
 int Field::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Field)
   int total_size = 0;
 
   // optional .google.protobuf.Field.Kind kind = 1;
@@ -1559,18 +1580,22 @@ int Field::ByteSize() const {
 }
 
 void Field::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Field)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Field* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Field>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Field)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Field)
     MergeFrom(*source);
   }
 }
 
 void Field::MergeFrom(const Field& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Field)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   options_.MergeFrom(from.options_);
   if (from.kind() != 0) {
@@ -1607,12 +1632,14 @@ void Field::MergeFrom(const Field& from) {
 }
 
 void Field::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Field)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Field::CopyFrom(const Field& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Field)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1725,6 +1752,7 @@ void Field::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Field::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1768,6 +1796,7 @@ void Field::clear_type_url() {
   return type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Field::release_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.type_url)
   
   return type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1869,6 +1898,7 @@ void Field::clear_json_name() {
   return json_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Field::release_json_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.json_name)
   
   return json_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1912,6 +1942,7 @@ void Field::clear_default_value() {
   return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Field::release_default_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.default_value)
   
   return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2003,6 +2034,7 @@ Enum* Enum::New(::google::protobuf::Arena* arena) const {
 }
 
 void Enum::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Enum)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   if (GetArenaNoVirtual() == NULL && source_context_ != NULL) delete source_context_;
   source_context_ = NULL;
@@ -2013,7 +2045,7 @@ void Enum::Clear() {
 
 bool Enum::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Enum)
   for (;;) {
@@ -2206,6 +2238,7 @@ void Enum::SerializeWithCachedSizes(
 }
 
 int Enum::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Enum)
   int total_size = 0;
 
   // optional string name = 1;
@@ -2251,18 +2284,22 @@ int Enum::ByteSize() const {
 }
 
 void Enum::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Enum)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Enum* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Enum>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Enum)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Enum)
     MergeFrom(*source);
   }
 }
 
 void Enum::MergeFrom(const Enum& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Enum)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   enumvalue_.MergeFrom(from.enumvalue_);
   options_.MergeFrom(from.options_);
@@ -2279,12 +2316,14 @@ void Enum::MergeFrom(const Enum& from) {
 }
 
 void Enum::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Enum)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Enum::CopyFrom(const Enum& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Enum)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2350,6 +2389,7 @@ void Enum::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Enum::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Enum.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2444,6 +2484,7 @@ const ::google::protobuf::SourceContext& Enum::source_context() const {
   return source_context_;
 }
 ::google::protobuf::SourceContext* Enum::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Enum.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -2547,6 +2588,7 @@ EnumValue* EnumValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void EnumValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.EnumValue)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   number_ = 0;
   options_.Clear();
@@ -2554,7 +2596,7 @@ void EnumValue::Clear() {
 
 bool EnumValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.EnumValue)
   for (;;) {
@@ -2689,6 +2731,7 @@ void EnumValue::SerializeWithCachedSizes(
 }
 
 int EnumValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.EnumValue)
   int total_size = 0;
 
   // optional string name = 1;
@@ -2720,18 +2763,22 @@ int EnumValue::ByteSize() const {
 }
 
 void EnumValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.EnumValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const EnumValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const EnumValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.EnumValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.EnumValue)
     MergeFrom(*source);
   }
 }
 
 void EnumValue::MergeFrom(const EnumValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.EnumValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   options_.MergeFrom(from.options_);
   if (from.name().size() > 0) {
@@ -2744,12 +2791,14 @@ void EnumValue::MergeFrom(const EnumValue& from) {
 }
 
 void EnumValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.EnumValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void EnumValue::CopyFrom(const EnumValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.EnumValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2813,6 +2862,7 @@ void EnumValue::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* EnumValue::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValue.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -2944,6 +2994,7 @@ Option* Option::New(::google::protobuf::Arena* arena) const {
 }
 
 void Option::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Option)
   name_.ClearToEmptyNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
   if (GetArenaNoVirtual() == NULL && value_ != NULL) delete value_;
   value_ = NULL;
@@ -2951,7 +3002,7 @@ void Option::Clear() {
 
 bool Option::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Option)
   for (;;) {
@@ -3057,6 +3108,7 @@ void Option::SerializeWithCachedSizes(
 }
 
 int Option::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Option)
   int total_size = 0;
 
   // optional string name = 1;
@@ -3080,18 +3132,22 @@ int Option::ByteSize() const {
 }
 
 void Option::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Option)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Option* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Option>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Option)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Option)
     MergeFrom(*source);
   }
 }
 
 void Option::MergeFrom(const Option& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Option)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.name().size() > 0) {
 
@@ -3103,12 +3159,14 @@ void Option::MergeFrom(const Option& from) {
 }
 
 void Option::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Option)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Option::CopyFrom(const Option& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Option)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -3171,6 +3229,7 @@ void Option::clear_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
  ::std::string* Option::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Option.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -3205,6 +3264,7 @@ const ::google::protobuf::Any& Option::value() const {
   return value_;
 }
 ::google::protobuf::Any* Option::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Option.value)
   
   ::google::protobuf::Any* temp = value_;
   value_ = NULL;
diff --git a/src/google/protobuf/type.pb.h b/src/google/protobuf/type.pb.h
index 76fe8a65..4255fa8c 100644
--- a/src/google/protobuf/type.pb.h
+++ b/src/google/protobuf/type.pb.h
@@ -328,25 +328,44 @@ class LIBPROTOBUF_EXPORT Field : public ::google::protobuf::Message {
   // nested types ----------------------------------------------------
 
   typedef Field_Kind Kind;
-  static const Kind TYPE_UNKNOWN = Field_Kind_TYPE_UNKNOWN;
-  static const Kind TYPE_DOUBLE = Field_Kind_TYPE_DOUBLE;
-  static const Kind TYPE_FLOAT = Field_Kind_TYPE_FLOAT;
-  static const Kind TYPE_INT64 = Field_Kind_TYPE_INT64;
-  static const Kind TYPE_UINT64 = Field_Kind_TYPE_UINT64;
-  static const Kind TYPE_INT32 = Field_Kind_TYPE_INT32;
-  static const Kind TYPE_FIXED64 = Field_Kind_TYPE_FIXED64;
-  static const Kind TYPE_FIXED32 = Field_Kind_TYPE_FIXED32;
-  static const Kind TYPE_BOOL = Field_Kind_TYPE_BOOL;
-  static const Kind TYPE_STRING = Field_Kind_TYPE_STRING;
-  static const Kind TYPE_GROUP = Field_Kind_TYPE_GROUP;
-  static const Kind TYPE_MESSAGE = Field_Kind_TYPE_MESSAGE;
-  static const Kind TYPE_BYTES = Field_Kind_TYPE_BYTES;
-  static const Kind TYPE_UINT32 = Field_Kind_TYPE_UINT32;
-  static const Kind TYPE_ENUM = Field_Kind_TYPE_ENUM;
-  static const Kind TYPE_SFIXED32 = Field_Kind_TYPE_SFIXED32;
-  static const Kind TYPE_SFIXED64 = Field_Kind_TYPE_SFIXED64;
-  static const Kind TYPE_SINT32 = Field_Kind_TYPE_SINT32;
-  static const Kind TYPE_SINT64 = Field_Kind_TYPE_SINT64;
+  static const Kind TYPE_UNKNOWN =
+    Field_Kind_TYPE_UNKNOWN;
+  static const Kind TYPE_DOUBLE =
+    Field_Kind_TYPE_DOUBLE;
+  static const Kind TYPE_FLOAT =
+    Field_Kind_TYPE_FLOAT;
+  static const Kind TYPE_INT64 =
+    Field_Kind_TYPE_INT64;
+  static const Kind TYPE_UINT64 =
+    Field_Kind_TYPE_UINT64;
+  static const Kind TYPE_INT32 =
+    Field_Kind_TYPE_INT32;
+  static const Kind TYPE_FIXED64 =
+    Field_Kind_TYPE_FIXED64;
+  static const Kind TYPE_FIXED32 =
+    Field_Kind_TYPE_FIXED32;
+  static const Kind TYPE_BOOL =
+    Field_Kind_TYPE_BOOL;
+  static const Kind TYPE_STRING =
+    Field_Kind_TYPE_STRING;
+  static const Kind TYPE_GROUP =
+    Field_Kind_TYPE_GROUP;
+  static const Kind TYPE_MESSAGE =
+    Field_Kind_TYPE_MESSAGE;
+  static const Kind TYPE_BYTES =
+    Field_Kind_TYPE_BYTES;
+  static const Kind TYPE_UINT32 =
+    Field_Kind_TYPE_UINT32;
+  static const Kind TYPE_ENUM =
+    Field_Kind_TYPE_ENUM;
+  static const Kind TYPE_SFIXED32 =
+    Field_Kind_TYPE_SFIXED32;
+  static const Kind TYPE_SFIXED64 =
+    Field_Kind_TYPE_SFIXED64;
+  static const Kind TYPE_SINT32 =
+    Field_Kind_TYPE_SINT32;
+  static const Kind TYPE_SINT64 =
+    Field_Kind_TYPE_SINT64;
   static inline bool Kind_IsValid(int value) {
     return Field_Kind_IsValid(value);
   }
@@ -369,10 +388,14 @@ class LIBPROTOBUF_EXPORT Field : public ::google::protobuf::Message {
   }
 
   typedef Field_Cardinality Cardinality;
-  static const Cardinality CARDINALITY_UNKNOWN = Field_Cardinality_CARDINALITY_UNKNOWN;
-  static const Cardinality CARDINALITY_OPTIONAL = Field_Cardinality_CARDINALITY_OPTIONAL;
-  static const Cardinality CARDINALITY_REQUIRED = Field_Cardinality_CARDINALITY_REQUIRED;
-  static const Cardinality CARDINALITY_REPEATED = Field_Cardinality_CARDINALITY_REPEATED;
+  static const Cardinality CARDINALITY_UNKNOWN =
+    Field_Cardinality_CARDINALITY_UNKNOWN;
+  static const Cardinality CARDINALITY_OPTIONAL =
+    Field_Cardinality_CARDINALITY_OPTIONAL;
+  static const Cardinality CARDINALITY_REQUIRED =
+    Field_Cardinality_CARDINALITY_REQUIRED;
+  static const Cardinality CARDINALITY_REPEATED =
+    Field_Cardinality_CARDINALITY_REPEATED;
   static inline bool Cardinality_IsValid(int value) {
     return Field_Cardinality_IsValid(value);
   }
@@ -865,6 +888,7 @@ inline ::std::string* Type::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Type::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Type.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -937,6 +961,7 @@ inline void Type::set_oneofs(int index, const char* value, size_t size) {
   // @@protoc_insertion_point(field_set_pointer:google.protobuf.Type.oneofs)
 }
 inline ::std::string* Type::add_oneofs() {
+  // @@protoc_insertion_point(field_add_mutable:google.protobuf.Type.oneofs)
   return oneofs_.Add();
 }
 inline void Type::add_oneofs(const ::std::string& value) {
@@ -1013,6 +1038,7 @@ inline ::google::protobuf::SourceContext* Type::mutable_source_context() {
   return source_context_;
 }
 inline ::google::protobuf::SourceContext* Type::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Type.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -1119,6 +1145,7 @@ inline ::std::string* Field::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Field::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1162,6 +1189,7 @@ inline ::std::string* Field::mutable_type_url() {
   return type_url_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Field::release_type_url() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.type_url)
   
   return type_url_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1263,6 +1291,7 @@ inline ::std::string* Field::mutable_json_name() {
   return json_name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Field::release_json_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.json_name)
   
   return json_name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1306,6 +1335,7 @@ inline ::std::string* Field::mutable_default_value() {
   return default_value_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Field::release_default_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Field.default_value)
   
   return default_value_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1353,6 +1383,7 @@ inline ::std::string* Enum::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Enum::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Enum.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1447,6 +1478,7 @@ inline ::google::protobuf::SourceContext* Enum::mutable_source_context() {
   return source_context_;
 }
 inline ::google::protobuf::SourceContext* Enum::release_source_context() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Enum.source_context)
   
   ::google::protobuf::SourceContext* temp = source_context_;
   source_context_ = NULL;
@@ -1511,6 +1543,7 @@ inline ::std::string* EnumValue::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* EnumValue::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.EnumValue.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1602,6 +1635,7 @@ inline ::std::string* Option::mutable_name() {
   return name_.MutableNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
 inline ::std::string* Option::release_name() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Option.name)
   
   return name_.ReleaseNoArena(&::google::protobuf::internal::GetEmptyStringAlreadyInited());
 }
@@ -1636,6 +1670,7 @@ inline ::google::protobuf::Any* Option::mutable_value() {
   return value_;
 }
 inline ::google::protobuf::Any* Option::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.Option.value)
   
   ::google::protobuf::Any* temp = value_;
   value_ = NULL;
diff --git a/src/google/protobuf/unittest_proto3_arena_lite.proto b/src/google/protobuf/unittest_proto3_arena_lite.proto
new file mode 100644
index 00000000..5a60b90f
--- /dev/null
+++ b/src/google/protobuf/unittest_proto3_arena_lite.proto
@@ -0,0 +1,207 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+option cc_enable_arenas = true;
+option optimize_for = LITE_RUNTIME;
+
+import "google/protobuf/unittest_import.proto";
+
+package proto3_arena_lite_unittest;
+
+// This proto includes every type of field in both singular and repeated
+// forms.
+message TestAllTypes {
+  message NestedMessage {
+    // The field name "b" fails to compile in proto1 because it conflicts with
+    // a local variable named "b" in one of the generated methods.  Doh.
+    // This file needs to compile in proto1 to test backwards-compatibility.
+    int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    ZERO = 0;
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+    NEG = -1;  // Intentionally negative.
+  }
+
+  // Singular
+     int32 optional_int32    =  1;
+     int64 optional_int64    =  2;
+    uint32 optional_uint32   =  3;
+    uint64 optional_uint64   =  4;
+    sint32 optional_sint32   =  5;
+    sint64 optional_sint64   =  6;
+   fixed32 optional_fixed32  =  7;
+   fixed64 optional_fixed64  =  8;
+  sfixed32 optional_sfixed32 =  9;
+  sfixed64 optional_sfixed64 = 10;
+     float optional_float    = 11;
+    double optional_double   = 12;
+      bool optional_bool     = 13;
+    string optional_string   = 14;
+     bytes optional_bytes    = 15;
+
+  // Groups are not allowed in proto3.
+  // optional group OptionalGroup = 16 {
+  //   optional int32 a = 17;
+  // }
+
+  NestedMessage                        optional_nested_message  = 18;
+  ForeignMessage                       optional_foreign_message = 19;
+  protobuf_unittest_import.ImportMessage optional_import_message  = 20;
+
+  NestedEnum                           optional_nested_enum     = 21;
+  ForeignEnum                          optional_foreign_enum    = 22;
+
+  // Omitted (compared to unittest.proto) because proto2 enums are not allowed
+  // inside proto2 messages.
+  //
+  // optional protobuf_unittest_import.ImportEnum    optional_import_enum  = 23;
+
+  string optional_string_piece = 24 [ctype=STRING_PIECE];
+  string optional_cord = 25 [ctype=CORD];
+
+  // Defined in unittest_import_public.proto
+  protobuf_unittest_import.PublicImportMessage
+      optional_public_import_message = 26;
+
+  NestedMessage optional_lazy_message = 27 [lazy=true];
+
+  // Repeated
+  repeated    int32 repeated_int32    = 31;
+  repeated    int64 repeated_int64    = 32;
+  repeated   uint32 repeated_uint32   = 33;
+  repeated   uint64 repeated_uint64   = 34;
+  repeated   sint32 repeated_sint32   = 35;
+  repeated   sint64 repeated_sint64   = 36;
+  repeated  fixed32 repeated_fixed32  = 37;
+  repeated  fixed64 repeated_fixed64  = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated    float repeated_float    = 41;
+  repeated   double repeated_double   = 42;
+  repeated     bool repeated_bool     = 43;
+  repeated   string repeated_string   = 44;
+  repeated    bytes repeated_bytes    = 45;
+
+  // Groups are not allowed in proto3.
+  // repeated group RepeatedGroup = 46 {
+  //   optional int32 a = 47;
+  // }
+
+  repeated NestedMessage                        repeated_nested_message  = 48;
+  repeated ForeignMessage                       repeated_foreign_message = 49;
+  repeated protobuf_unittest_import.ImportMessage repeated_import_message  = 50;
+
+  repeated NestedEnum                           repeated_nested_enum     = 51;
+  repeated ForeignEnum                          repeated_foreign_enum    = 52;
+
+  // Omitted (compared to unittest.proto) because proto2 enums are not allowed
+  // inside proto2 messages.
+  //
+  // repeated protobuf_unittest_import.ImportEnum    repeated_import_enum  = 53;
+
+  repeated string repeated_string_piece = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype=CORD];
+
+  repeated NestedMessage repeated_lazy_message = 57 [lazy=true];
+
+  oneof oneof_field {
+    uint32 oneof_uint32 = 111;
+    NestedMessage oneof_nested_message = 112;
+    string oneof_string = 113;
+    bytes oneof_bytes = 114;
+  }
+}
+
+// Test messages for packed fields
+
+message TestPackedTypes {
+  repeated    int32 packed_int32    =  90 [packed = true];
+  repeated    int64 packed_int64    =  91 [packed = true];
+  repeated   uint32 packed_uint32   =  92 [packed = true];
+  repeated   uint64 packed_uint64   =  93 [packed = true];
+  repeated   sint32 packed_sint32   =  94 [packed = true];
+  repeated   sint64 packed_sint64   =  95 [packed = true];
+  repeated  fixed32 packed_fixed32  =  96 [packed = true];
+  repeated  fixed64 packed_fixed64  =  97 [packed = true];
+  repeated sfixed32 packed_sfixed32 =  98 [packed = true];
+  repeated sfixed64 packed_sfixed64 =  99 [packed = true];
+  repeated    float packed_float    = 100 [packed = true];
+  repeated   double packed_double   = 101 [packed = true];
+  repeated     bool packed_bool     = 102 [packed = true];
+  repeated ForeignEnum packed_enum  = 103 [packed = true];
+}
+
+// Explicitly set packed to false
+message TestUnpackedTypes {
+  repeated    int32 repeated_int32    =  1 [packed = false];
+  repeated    int64 repeated_int64    =  2 [packed = false];
+  repeated   uint32 repeated_uint32   =  3 [packed = false];
+  repeated   uint64 repeated_uint64   =  4 [packed = false];
+  repeated   sint32 repeated_sint32   =  5 [packed = false];
+  repeated   sint64 repeated_sint64   =  6 [packed = false];
+  repeated  fixed32 repeated_fixed32  =  7 [packed = false];
+  repeated  fixed64 repeated_fixed64  =  8 [packed = false];
+  repeated sfixed32 repeated_sfixed32 =  9 [packed = false];
+  repeated sfixed64 repeated_sfixed64 = 10 [packed = false];
+  repeated    float repeated_float    = 11 [packed = false];
+  repeated   double repeated_double   = 12 [packed = false];
+  repeated     bool repeated_bool     = 13 [packed = false];
+  repeated TestAllTypes.NestedEnum repeated_nested_enum = 14 [packed = false];
+}
+
+// This proto includes a recusively nested message.
+message NestedTestAllTypes {
+  NestedTestAllTypes child = 1;
+  TestAllTypes payload = 2;
+}
+
+// Define these after TestAllTypes to make sure the compiler can handle
+// that.
+message ForeignMessage {
+  int32 c = 1;
+}
+
+enum ForeignEnum {
+  FOREIGN_ZERO = 0;
+  FOREIGN_FOO = 4;
+  FOREIGN_BAR = 5;
+  FOREIGN_BAZ = 6;
+}
+
+// TestEmptyMessage is used to test behavior of unknown fields.
+message TestEmptyMessage {
+}
+
diff --git a/src/google/protobuf/unittest_proto3_lite.proto b/src/google/protobuf/unittest_proto3_lite.proto
new file mode 100644
index 00000000..874ade6c
--- /dev/null
+++ b/src/google/protobuf/unittest_proto3_lite.proto
@@ -0,0 +1,206 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+option optimize_for = LITE_RUNTIME;
+
+import "google/protobuf/unittest_import.proto";
+
+package proto3_lite_unittest;
+
+// This proto includes every type of field in both singular and repeated
+// forms.
+message TestAllTypes {
+  message NestedMessage {
+    // The field name "b" fails to compile in proto1 because it conflicts with
+    // a local variable named "b" in one of the generated methods.  Doh.
+    // This file needs to compile in proto1 to test backwards-compatibility.
+    int32 bb = 1;
+  }
+
+  enum NestedEnum {
+    ZERO = 0;
+    FOO = 1;
+    BAR = 2;
+    BAZ = 3;
+    NEG = -1;  // Intentionally negative.
+  }
+
+  // Singular
+     int32 optional_int32    =  1;
+     int64 optional_int64    =  2;
+    uint32 optional_uint32   =  3;
+    uint64 optional_uint64   =  4;
+    sint32 optional_sint32   =  5;
+    sint64 optional_sint64   =  6;
+   fixed32 optional_fixed32  =  7;
+   fixed64 optional_fixed64  =  8;
+  sfixed32 optional_sfixed32 =  9;
+  sfixed64 optional_sfixed64 = 10;
+     float optional_float    = 11;
+    double optional_double   = 12;
+      bool optional_bool     = 13;
+    string optional_string   = 14;
+     bytes optional_bytes    = 15;
+
+  // Groups are not allowed in proto3.
+  // optional group OptionalGroup = 16 {
+  //   optional int32 a = 17;
+  // }
+
+  NestedMessage                        optional_nested_message  = 18;
+  ForeignMessage                       optional_foreign_message = 19;
+  protobuf_unittest_import.ImportMessage optional_import_message  = 20;
+
+  NestedEnum                           optional_nested_enum     = 21;
+  ForeignEnum                          optional_foreign_enum    = 22;
+
+  // Omitted (compared to unittest.proto) because proto2 enums are not allowed
+  // inside proto2 messages.
+  //
+  // optional protobuf_unittest_import.ImportEnum    optional_import_enum  = 23;
+
+  string optional_string_piece = 24 [ctype=STRING_PIECE];
+  string optional_cord = 25 [ctype=CORD];
+
+  // Defined in unittest_import_public.proto
+  protobuf_unittest_import.PublicImportMessage
+      optional_public_import_message = 26;
+
+  NestedMessage optional_lazy_message = 27 [lazy=true];
+
+  // Repeated
+  repeated    int32 repeated_int32    = 31;
+  repeated    int64 repeated_int64    = 32;
+  repeated   uint32 repeated_uint32   = 33;
+  repeated   uint64 repeated_uint64   = 34;
+  repeated   sint32 repeated_sint32   = 35;
+  repeated   sint64 repeated_sint64   = 36;
+  repeated  fixed32 repeated_fixed32  = 37;
+  repeated  fixed64 repeated_fixed64  = 38;
+  repeated sfixed32 repeated_sfixed32 = 39;
+  repeated sfixed64 repeated_sfixed64 = 40;
+  repeated    float repeated_float    = 41;
+  repeated   double repeated_double   = 42;
+  repeated     bool repeated_bool     = 43;
+  repeated   string repeated_string   = 44;
+  repeated    bytes repeated_bytes    = 45;
+
+  // Groups are not allowed in proto3.
+  // repeated group RepeatedGroup = 46 {
+  //   optional int32 a = 47;
+  // }
+
+  repeated NestedMessage                        repeated_nested_message  = 48;
+  repeated ForeignMessage                       repeated_foreign_message = 49;
+  repeated protobuf_unittest_import.ImportMessage repeated_import_message  = 50;
+
+  repeated NestedEnum                           repeated_nested_enum     = 51;
+  repeated ForeignEnum                          repeated_foreign_enum    = 52;
+
+  // Omitted (compared to unittest.proto) because proto2 enums are not allowed
+  // inside proto2 messages.
+  //
+  // repeated protobuf_unittest_import.ImportEnum    repeated_import_enum  = 53;
+
+  repeated string repeated_string_piece = 54 [ctype=STRING_PIECE];
+  repeated string repeated_cord = 55 [ctype=CORD];
+
+  repeated NestedMessage repeated_lazy_message = 57 [lazy=true];
+
+  oneof oneof_field {
+    uint32 oneof_uint32 = 111;
+    NestedMessage oneof_nested_message = 112;
+    string oneof_string = 113;
+    bytes oneof_bytes = 114;
+  }
+}
+
+// Test messages for packed fields
+
+message TestPackedTypes {
+  repeated    int32 packed_int32    =  90 [packed = true];
+  repeated    int64 packed_int64    =  91 [packed = true];
+  repeated   uint32 packed_uint32   =  92 [packed = true];
+  repeated   uint64 packed_uint64   =  93 [packed = true];
+  repeated   sint32 packed_sint32   =  94 [packed = true];
+  repeated   sint64 packed_sint64   =  95 [packed = true];
+  repeated  fixed32 packed_fixed32  =  96 [packed = true];
+  repeated  fixed64 packed_fixed64  =  97 [packed = true];
+  repeated sfixed32 packed_sfixed32 =  98 [packed = true];
+  repeated sfixed64 packed_sfixed64 =  99 [packed = true];
+  repeated    float packed_float    = 100 [packed = true];
+  repeated   double packed_double   = 101 [packed = true];
+  repeated     bool packed_bool     = 102 [packed = true];
+  repeated ForeignEnum packed_enum  = 103 [packed = true];
+}
+
+// Explicitly set packed to false
+message TestUnpackedTypes {
+  repeated    int32 repeated_int32    =  1 [packed = false];
+  repeated    int64 repeated_int64    =  2 [packed = false];
+  repeated   uint32 repeated_uint32   =  3 [packed = false];
+  repeated   uint64 repeated_uint64   =  4 [packed = false];
+  repeated   sint32 repeated_sint32   =  5 [packed = false];
+  repeated   sint64 repeated_sint64   =  6 [packed = false];
+  repeated  fixed32 repeated_fixed32  =  7 [packed = false];
+  repeated  fixed64 repeated_fixed64  =  8 [packed = false];
+  repeated sfixed32 repeated_sfixed32 =  9 [packed = false];
+  repeated sfixed64 repeated_sfixed64 = 10 [packed = false];
+  repeated    float repeated_float    = 11 [packed = false];
+  repeated   double repeated_double   = 12 [packed = false];
+  repeated     bool repeated_bool     = 13 [packed = false];
+  repeated TestAllTypes.NestedEnum repeated_nested_enum = 14 [packed = false];
+}
+
+// This proto includes a recusively nested message.
+message NestedTestAllTypes {
+  NestedTestAllTypes child = 1;
+  TestAllTypes payload = 2;
+}
+
+// Define these after TestAllTypes to make sure the compiler can handle
+// that.
+message ForeignMessage {
+  int32 c = 1;
+}
+
+enum ForeignEnum {
+  FOREIGN_ZERO = 0;
+  FOREIGN_FOO = 4;
+  FOREIGN_BAR = 5;
+  FOREIGN_BAZ = 6;
+}
+
+// TestEmptyMessage is used to test behavior of unknown fields.
+message TestEmptyMessage {
+}
+
diff --git a/src/google/protobuf/util/field_comparator.cc b/src/google/protobuf/util/field_comparator.cc
index 9f613265..60b8b8a5 100644
--- a/src/google/protobuf/util/field_comparator.cc
+++ b/src/google/protobuf/util/field_comparator.cc
@@ -92,7 +92,27 @@ FieldComparator::ComparisonResult DefaultFieldComparator::Compare(
     case FieldDescriptor::CPPTYPE_INT64:
       COMPARE_FIELD(Int64);
     case FieldDescriptor::CPPTYPE_STRING:
-      COMPARE_FIELD(String);
+      if (field->is_repeated()) {
+        // Allocate scratch strings to store the result if a conversion is
+        // needed.
+        string scratch1;
+        string scratch2;
+        return ResultFromBoolean(
+            CompareString(*field, reflection_1->GetRepeatedStringReference(
+                                      message_1, field, index_1, &scratch1),
+                          reflection_2->GetRepeatedStringReference(
+                              message_2, field, index_2, &scratch2)));
+      } else {
+        // Allocate scratch strings to store the result if a conversion is
+        // needed.
+        string scratch1;
+        string scratch2;
+        return ResultFromBoolean(CompareString(
+            *field,
+            reflection_1->GetStringReference(message_1, field, &scratch1),
+            reflection_2->GetStringReference(message_2, field, &scratch2)));
+      }
+      break;
     case FieldDescriptor::CPPTYPE_UINT32:
       COMPARE_FIELD(UInt32);
     case FieldDescriptor::CPPTYPE_UINT64:
diff --git a/src/google/protobuf/util/field_mask_util_test.cc b/src/google/protobuf/util/field_mask_util_test.cc
index b3787857..9b7fb62a 100644
--- a/src/google/protobuf/util/field_mask_util_test.cc
+++ b/src/google/protobuf/util/field_mask_util_test.cc
@@ -30,6 +30,8 @@
 
 #include <google/protobuf/util/field_mask_util.h>
 
+#include <algorithm>
+
 #include <google/protobuf/stubs/logging.h>
 #include <google/protobuf/stubs/common.h>
 #include <google/protobuf/field_mask.pb.h>
diff --git a/src/google/protobuf/util/internal/protostream_objectsource.cc b/src/google/protobuf/util/internal/protostream_objectsource.cc
index 297c011a..1f3781a4 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource.cc
+++ b/src/google/protobuf/util/internal/protostream_objectsource.cc
@@ -70,6 +70,9 @@ using util::Status;
 using util::StatusOr;
 
 namespace {
+
+static int kDefaultMaxRecursionDepth = 64;
+
 // Finds a field with the given number. NULL if none found.
 const google::protobuf::Field* FindFieldByNumber(
     const google::protobuf::Type& type, int number);
@@ -116,7 +119,9 @@ ProtoStreamObjectSource::ProtoStreamObjectSource(
       typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
       own_typeinfo_(true),
       type_(type),
-      use_lower_camel_for_enums_(false) {
+      use_lower_camel_for_enums_(false),
+      recursion_depth_(0),
+      max_recursion_depth_(kDefaultMaxRecursionDepth) {
   GOOGLE_LOG_IF(DFATAL, stream == NULL) << "Input stream is NULL.";
 }
 
@@ -127,7 +132,9 @@ ProtoStreamObjectSource::ProtoStreamObjectSource(
       typeinfo_(typeinfo),
       own_typeinfo_(false),
       type_(type),
-      use_lower_camel_for_enums_(false) {
+      use_lower_camel_for_enums_(false),
+      recursion_depth_(0),
+      max_recursion_depth_(kDefaultMaxRecursionDepth) {
   GOOGLE_LOG_IF(DFATAL, stream == NULL) << "Input stream is NULL.";
 }
 
@@ -741,7 +748,9 @@ Status ProtoStreamObjectSource::RenderField(
     if (use_type_renderer) {
       RETURN_IF_ERROR((*type_renderer)(this, *type, field_name, ow));
     } else {
+      RETURN_IF_ERROR(IncrementRecursionDepth(type->name(), field_name));
       RETURN_IF_ERROR(WriteMessage(*type, field_name, 0, true, ow));
+      --recursion_depth_;
     }
     if (!stream_->ConsumedEntireMessage()) {
       return Status(util::error::INVALID_ARGUMENT,
@@ -1037,6 +1046,17 @@ std::pair<int64, int32> ProtoStreamObjectSource::ReadSecondsAndNanos(
   return std::pair<int64, int32>(signed_seconds, signed_nanos);
 }
 
+Status ProtoStreamObjectSource::IncrementRecursionDepth(
+    StringPiece type_name, StringPiece field_name) const {
+  if (++recursion_depth_ > max_recursion_depth_) {
+    return Status(
+        util::error::INVALID_ARGUMENT,
+        StrCat("Message too deep. Max recursion depth reached for type '",
+               type_name, "', field '", field_name, "'"));
+  }
+  return Status::OK;
+}
+
 namespace {
 // TODO(skarvaje): Speed this up by not doing a linear scan.
 const google::protobuf::Field* FindFieldByNumber(
diff --git a/src/google/protobuf/util/internal/protostream_objectsource.h b/src/google/protobuf/util/internal/protostream_objectsource.h
index 17e03b73..d7d4347b 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource.h
+++ b/src/google/protobuf/util/internal/protostream_objectsource.h
@@ -110,6 +110,13 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
     use_lower_camel_for_enums_ = value;
   }
 
+  // Sets the max recursion depth of proto message to be deserialized. Proto
+  // messages over this depth will fail to be deserialized.
+  // Default value is 64.
+  void set_max_recursion_depth(int max_depth) {
+    max_recursion_depth_ = max_depth;
+  }
+
  protected:
   // Writes a proto2 Message to the ObjectWriter. When the given end_tag is
   // found this method will complete, allowing it to be used for parsing both
@@ -251,6 +258,12 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
   std::pair<int64, int32> ReadSecondsAndNanos(
       const google::protobuf::Type& type) const;
 
+  // Helper function to check recursion depth and increment it. It will return
+  // Status::OK if the current depth is allowed. Otherwise an error is returned.
+  // type_name and field_name are used for error reporting.
+  util::Status IncrementRecursionDepth(StringPiece type_name,
+                                         StringPiece field_name) const;
+
   // Input stream to read from. Ownership rests with the caller.
   google::protobuf::io::CodedInputStream* stream_;
 
@@ -268,6 +281,12 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectSource : public ObjectSource {
   // Whether to render enums using lowerCamelCase. Defaults to false.
   bool use_lower_camel_for_enums_;
 
+  // Tracks current recursion depth.
+  mutable int recursion_depth_;
+
+  // Maximum allowed recursion depth.
+  int max_recursion_depth_;
+
   GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(ProtoStreamObjectSource);
 };
 
diff --git a/src/google/protobuf/util/internal/protostream_objectsource_test.cc b/src/google/protobuf/util/internal/protostream_objectsource_test.cc
index 1b32c803..3f6fdf97 100644
--- a/src/google/protobuf/util/internal/protostream_objectsource_test.cc
+++ b/src/google/protobuf/util/internal/protostream_objectsource_test.cc
@@ -70,6 +70,7 @@ using google::protobuf::testing::Author;
 using google::protobuf::testing::BadAuthor;
 using google::protobuf::testing::BadNestedBook;
 using google::protobuf::testing::Book;
+using google::protobuf::testing::Cyclic;
 using google::protobuf::testing::Book_Label;
 using google::protobuf::testing::NestedBook;
 using google::protobuf::testing::PackedPrimitive;
@@ -120,6 +121,7 @@ class ProtostreamObjectSourceTest
     google::protobuf::scoped_ptr<ProtoStreamObjectSource> os(
         helper_.NewProtoSource(&in_stream, GetTypeUrl(descriptor)));
     if (use_lower_camel_for_enums_) os->set_use_lower_camel_for_enums(true);
+    os->set_max_recursion_depth(64);
     return os->WriteTo(&mock_);
   }
 
@@ -491,6 +493,33 @@ TEST_P(ProtostreamObjectSourceTest, EnumCaseIsUnchangedByDefault) {
   DoTest(book, Book::descriptor());
 }
 
+TEST_P(ProtostreamObjectSourceTest, CyclicMessageDepthTest) {
+  Cyclic cyclic;
+  cyclic.set_m_int(123);
+
+  Book* book = cyclic.mutable_m_book();
+  book->set_title("book title");
+  Cyclic* current = cyclic.mutable_m_cyclic();
+  Author* current_author = cyclic.add_m_author();
+  for (int i = 0; i < 63; ++i) {
+    Author* next = current_author->add_friend_();
+    next->set_id(i);
+    next->set_name(StrCat("author_name_", i));
+    next->set_alive(true);
+    current_author = next;
+  }
+
+  // Recursive message with depth (65) > max (max is 64).
+  for (int i = 0; i < 64; ++i) {
+    Cyclic* next = current->mutable_m_cyclic();
+    next->set_m_str(StrCat("count_", i));
+    current = next;
+  }
+
+  Status status = ExecuteTest(cyclic, Cyclic::descriptor());
+  EXPECT_EQ(util::error::INVALID_ARGUMENT, status.error_code());
+}
+
 class ProtostreamObjectSourceMapsTest : public ProtostreamObjectSourceTest {
  protected:
   ProtostreamObjectSourceMapsTest() {
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter.cc b/src/google/protobuf/util/internal/protostream_objectwriter.cc
index 94ddb428..97a7909a 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter.cc
+++ b/src/google/protobuf/util/internal/protostream_objectwriter.cc
@@ -182,7 +182,8 @@ ProtoStreamObjectWriter::AnyWriter::AnyWriter(ProtoStreamObjectWriter* parent)
       data_(),
       output_(&data_),
       depth_(0),
-      has_injected_value_message_(false) {}
+      is_well_known_type_(false),
+      well_known_type_render_(NULL) {}
 
 ProtoStreamObjectWriter::AnyWriter::~AnyWriter() {}
 
@@ -200,10 +201,19 @@ void ProtoStreamObjectWriter::AnyWriter::StartObject(StringPiece name) {
                                    parent_->master_type_.name()));
       invalid_ = true;
     }
-  } else if (!has_injected_value_message_ || depth_ != 1 || name != "value") {
-    // We don't propagate to ow_ StartObject("value") calls for nested Anys or
-    // Struct at depth 1 as they are nested one level deep with an injected
+  } else if (is_well_known_type_ && depth_ == 1) {
+    // For well-known types, the only other field besides "@type" should be a
     // "value" field.
+    if (name != "value" && !invalid_) {
+      parent_->InvalidValue("Any",
+                            "Expect a \"value\" field for well-known types.");
+      invalid_ = true;
+    }
+    ow_->StartObject("");
+  } else {
+    // Forward the call to the child writer if:
+    //   1. the type is not a well-known type.
+    //   2. or, we are in a nested Any, Struct, or Value object.
     ow_->StartObject(name);
   }
 }
@@ -211,10 +221,9 @@ void ProtoStreamObjectWriter::AnyWriter::StartObject(StringPiece name) {
 bool ProtoStreamObjectWriter::AnyWriter::EndObject() {
   --depth_;
   // As long as depth_ >= 0, we know we haven't reached the end of Any.
-  // Propagate these EndObject() calls to the contained ow_.  If we are in a
-  // nested Any or Struct type, ignore the second to last EndObject call (depth_
-  // == -1)
-  if (ow_ != NULL && (!has_injected_value_message_ || depth_ >= 0)) {
+  // Propagate these EndObject() calls to the contained ow_. For regular
+  // message types, we propagate the end of Any as well.
+  if (ow_ != NULL && (depth_ >= 0 || !is_well_known_type_)) {
     ow_->EndObject();
   }
   // A negative depth_ implies that we have reached the end of Any
@@ -236,6 +245,13 @@ void ProtoStreamObjectWriter::AnyWriter::StartList(StringPiece name) {
                                    parent_->master_type_.name()));
       invalid_ = true;
     }
+  } else if (is_well_known_type_ && depth_ == 1) {
+    if (name != "value" && !invalid_) {
+      parent_->InvalidValue("Any",
+                            "Expect a \"value\" field for well-known types.");
+      invalid_ = true;
+    }
+    ow_->StartList("");
   } else {
     ow_->StartList(name);
   }
@@ -266,17 +282,27 @@ void ProtoStreamObjectWriter::AnyWriter::RenderDataPiece(
                                    parent_->master_type_.name()));
       invalid_ = true;
     }
-  } else {
-    // Check to see if the data needs to be rendered with well-known-type
-    // renderer.
-    const TypeRenderer* type_renderer =
-        FindTypeRenderer(GetFullTypeWithUrl(ow_->master_type_.name()));
-    if (type_renderer) {
-      Status status = (*type_renderer)(ow_.get(), value);
-      if (!status.ok()) ow_->InvalidValue("Any", status.error_message());
+  } else if (depth_ == 0 && is_well_known_type_) {
+    if (name != "value" && !invalid_) {
+      parent_->InvalidValue("Any",
+                            "Expect a \"value\" field for well-known types.");
+      invalid_ = true;
+    }
+    if (well_known_type_render_ == NULL) {
+      // Only Any and Struct don't have a special type render but both of
+      // them expect a JSON object (i.e., a StartObject() call).
+      if (!invalid_) {
+        parent_->InvalidValue("Any", "Expect a JSON object.");
+        invalid_ = true;
+      }
     } else {
-      ow_->RenderDataPiece(name, value);
+      ow_->ProtoWriter::StartObject("");
+      Status status = (*well_known_type_render_)(ow_.get(), value);
+      if (!status.ok()) ow_->InvalidValue("Any", status.error_message());
+      ow_->ProtoWriter::EndObject();
     }
+  } else {
+    ow_->RenderDataPiece(name, value);
   }
 }
 
@@ -305,19 +331,31 @@ void ProtoStreamObjectWriter::AnyWriter::StartAny(const DataPiece& value) {
   // At this point, type is never null.
   const google::protobuf::Type* type = resolved_type.ValueOrDie();
 
-  // If this is the case of an Any in an Any or Struct in an Any, we need to
-  // expect a StartObject call with "value" while we're at depth_ 0, which we
-  // should ignore (not propagate to our nested object writer). We also need to
-  // ignore the second-to-last EndObject call, and not propagate that either.
-  if (type->name() == kAnyType || type->name() == kStructType) {
-    has_injected_value_message_ = true;
+  well_known_type_render_ = FindTypeRenderer(type_url_);
+  if (well_known_type_render_ != NULL ||
+      // Explicitly list Any and Struct here because they don't have a
+      // custom renderer.
+      type->name() == kAnyType || type->name() == kStructType) {
+    is_well_known_type_ = true;
   }
 
   // Create our object writer and initialize it with the first StartObject
   // call.
   ow_.reset(new ProtoStreamObjectWriter(parent_->typeinfo(), *type, &output_,
                                         parent_->listener()));
-  ow_->StartObject("");
+
+  // Don't call StartObject() for well-known types yet. Depending on the
+  // type of actual data, we may not need to call StartObject(). For
+  // example:
+  // {
+  //   "@type": "type.googleapis.com/google.protobuf.Value",
+  //   "value": [1, 2, 3],
+  // }
+  // With the above JSON representation, we will only call StartList() on the
+  // contained ow_.
+  if (!is_well_known_type_) {
+    ow_->StartObject("");
+  }
 }
 
 void ProtoStreamObjectWriter::AnyWriter::WriteAny() {
@@ -861,7 +899,7 @@ Status ProtoStreamObjectWriter::RenderFieldMask(ProtoStreamObjectWriter* ow,
 // conversions as much as possible. Because ToSnakeCase sometimes returns the
 // wrong value.
   google::protobuf::scoped_ptr<ResultCallback1<util::Status, StringPiece> > callback(
-      google::protobuf::internal::NewPermanentCallback(&RenderOneFieldPath, ow));
+      ::google::protobuf::internal::NewPermanentCallback(&RenderOneFieldPath, ow));
   return DecodeCompactFieldMaskPaths(data.str(), callback.get());
 }
 
@@ -986,6 +1024,7 @@ ProtoStreamObjectWriter* ProtoStreamObjectWriter::RenderDataPiece(
     // not of the google.protobuf.NullType type, we do nothing.
     if (data.type() == DataPiece::TYPE_NULL &&
         field->type_url() != kStructNullValueTypeUrl) {
+      Pop();
       return this;
     }
 
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter.h b/src/google/protobuf/util/internal/protostream_objectwriter.h
index 96ea3f2b..e1162d43 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter.h
+++ b/src/google/protobuf/util/internal/protostream_objectwriter.h
@@ -167,9 +167,14 @@ class LIBPROTOBUF_EXPORT ProtoStreamObjectWriter : public ProtoWriter {
     // The depth within the Any, so we can track when we're done.
     int depth_;
 
-    // True if the message type contained in Any has a special "value" message
-    // injected. This is true for well-known message types like Any or Struct.
-    bool has_injected_value_message_;
+    // True if the type is a well-known type. Well-known types in Any
+    // has a special formating:
+    // {
+    //   "@type": "type.googleapis.com/google.protobuf.XXX",
+    //   "value": <JSON representation of the type>,
+    // }
+    bool is_well_known_type_;
+    TypeRenderer* well_known_type_render_;
   };
 
   // Represents an item in a stack of items used to keep state between
diff --git a/src/google/protobuf/util/internal/protostream_objectwriter_test.cc b/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
index 41eaebc0..9a0dcde1 100644
--- a/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
+++ b/src/google/protobuf/util/internal/protostream_objectwriter_test.cc
@@ -1413,6 +1413,8 @@ class ProtoStreamObjectWriterAnyTest : public BaseProtoStreamObjectWriterTest {
     descriptors.push_back(google::protobuf::DoubleValue::descriptor());
     descriptors.push_back(google::protobuf::Timestamp::descriptor());
     descriptors.push_back(google::protobuf::Any::descriptor());
+    descriptors.push_back(google::protobuf::Value::descriptor());
+    descriptors.push_back(google::protobuf::Struct::descriptor());
     ResetTypeInfo(descriptors);
   }
 };
@@ -1621,6 +1623,222 @@ TEST_P(ProtoStreamObjectWriterAnyTest, AnyWellKnownTypeErrorTest) {
   CheckOutput(any);
 }
 
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "value": "abc"
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWithNestedPrimitiveValue) {
+  AnyOut out;
+  ::google::protobuf::Any* any = out.mutable_any();
+
+  ::google::protobuf::Value value;
+  value.set_string_value("abc");
+  any->PackFrom(value);
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->RenderString("value", "abc")
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(out);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "value": {
+//       "foo": "abc"
+//     }
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWithNestedObjectValue) {
+  AnyOut out;
+  ::google::protobuf::Any* any = out.mutable_any();
+
+  ::google::protobuf::Value value;
+  (*value.mutable_struct_value()->mutable_fields())["foo"].set_string_value(
+      "abc");
+  any->PackFrom(value);
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->StartObject("value")
+      ->RenderString("foo", "abc")
+      ->EndObject()
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(out);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "value": ["hello"],
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWithNestedArrayValue) {
+  AnyOut out;
+  ::google::protobuf::Any* any = out.mutable_any();
+
+  ::google::protobuf::Value value;
+  value.mutable_list_value()->add_values()->set_string_value("hello");
+  any->PackFrom(value);
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->StartList("value")
+      ->RenderString("", "hello")
+      ->EndList()
+      ->EndObject()
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(out);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "not_value": ""
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest,
+       AnyWellKnownTypesNoValueFieldForPrimitive) {
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(
+          _, StringPiece("Any"),
+          StringPiece("Expect a \"value\" field for well-known types.")));
+  AnyOut any;
+  google::protobuf::Any* any_type = any.mutable_any();
+  any_type->set_type_url("type.googleapis.com/google.protobuf.Value");
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->RenderString("not_value", "")
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(any);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "not_value": {}
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWellKnownTypesNoValueFieldForObject) {
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(
+          _, StringPiece("Any"),
+          StringPiece("Expect a \"value\" field for well-known types.")));
+  AnyOut any;
+  google::protobuf::Any* any_type = any.mutable_any();
+  any_type->set_type_url("type.googleapis.com/google.protobuf.Value");
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->StartObject("not_value")
+      ->EndObject()
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(any);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Value",
+//     "not_value": [],
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWellKnownTypesNoValueFieldForArray) {
+  EXPECT_CALL(
+      listener_,
+      InvalidValue(
+          _, StringPiece("Any"),
+          StringPiece("Expect a \"value\" field for well-known types.")));
+  AnyOut any;
+  google::protobuf::Any* any_type = any.mutable_any();
+  any_type->set_type_url("type.googleapis.com/google.protobuf.Value");
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Value")
+      ->StartList("not_value")
+      ->EndList()
+      ->EndObject()
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(any);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Struct",
+//     "value": "",
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWellKnownTypesExpectObjectForStruct) {
+  EXPECT_CALL(listener_, InvalidValue(_, StringPiece("Any"),
+                                      StringPiece("Expect a JSON object.")));
+  AnyOut any;
+  google::protobuf::Any* any_type = any.mutable_any();
+  any_type->set_type_url("type.googleapis.com/google.protobuf.Struct");
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Struct")
+      ->RenderString("value", "")
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(any);
+}
+
+// Test the following case:
+//
+// {
+//   "any": {
+//     "@type": "type.googleapis.com/google.protobuf.Any",
+//     "value": "",
+//   }
+// }
+TEST_P(ProtoStreamObjectWriterAnyTest, AnyWellKnownTypesExpectObjectForAny) {
+  EXPECT_CALL(listener_, InvalidValue(_, StringPiece("Any"),
+                                      StringPiece("Expect a JSON object.")));
+  AnyOut any;
+  google::protobuf::Any* any_type = any.mutable_any();
+  any_type->set_type_url("type.googleapis.com/google.protobuf.Any");
+
+  ow_->StartObject("")
+      ->StartObject("any")
+      ->RenderString("@type", "type.googleapis.com/google.protobuf.Any")
+      ->RenderString("value", "")
+      ->EndObject()
+      ->EndObject();
+  CheckOutput(any);
+}
+
 class ProtoStreamObjectWriterFieldMaskTest
     : public BaseProtoStreamObjectWriterTest {
  protected:
diff --git a/src/google/protobuf/util/internal/testdata/books.proto b/src/google/protobuf/util/internal/testdata/books.proto
index 101a2bf0..1cbbba47 100644
--- a/src/google/protobuf/util/internal/testdata/books.proto
+++ b/src/google/protobuf/util/internal/testdata/books.proto
@@ -176,3 +176,12 @@ message NestedBook {
 message BadNestedBook {
   repeated uint32 book = 1 [packed=true];  // Packed to optional message.
 }
+
+// A recursively defined message.
+message Cyclic {
+  optional int32 m_int = 1;
+  optional string m_str = 2;
+  optional Book m_book = 3;
+  repeated Author m_author = 5;
+  optional Cyclic m_cyclic = 4;
+}
diff --git a/src/google/protobuf/util/message_differencer.cc b/src/google/protobuf/util/message_differencer.cc
index b2b3242a..fe8119bf 100644
--- a/src/google/protobuf/util/message_differencer.cc
+++ b/src/google/protobuf/util/message_differencer.cc
@@ -456,7 +456,9 @@ bool MessageDifferencer::Compare(
   const Descriptor* descriptor2 = message2.GetDescriptor();
   if (descriptor1 != descriptor2) {
     GOOGLE_LOG(DFATAL) << "Comparison between two messages with different "
-                << "descriptors.";
+                << "descriptors. "
+                << descriptor1->full_name() << " vs "
+                << descriptor2->full_name();
     return false;
   }
   // Expand google.protobuf.Any payload if possible.
@@ -1385,7 +1387,7 @@ bool MessageDifferencer::MatchRepeatedFieldIndices(
       // algorithm will fail to find a maximum matching.
       // Here we use the argumenting path algorithm.
       MaximumMatcher::NodeMatchCallback* callback =
-          google::protobuf::internal::NewPermanentCallback(
+          ::google::protobuf::internal::NewPermanentCallback(
               this, &MessageDifferencer::IsMatch,
               repeated_field, key_comparator,
               &message1, &message2, parent_fields);
diff --git a/src/google/protobuf/wrappers.pb.cc b/src/google/protobuf/wrappers.pb.cc
index 204c8029..60801423 100644
--- a/src/google/protobuf/wrappers.pb.cc
+++ b/src/google/protobuf/wrappers.pb.cc
@@ -388,12 +388,13 @@ DoubleValue* DoubleValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void DoubleValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.DoubleValue)
   value_ = 0;
 }
 
 bool DoubleValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.DoubleValue)
   for (;;) {
@@ -460,6 +461,7 @@ void DoubleValue::SerializeWithCachedSizes(
 }
 
 int DoubleValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.DoubleValue)
   int total_size = 0;
 
   // optional double value = 1;
@@ -474,18 +476,22 @@ int DoubleValue::ByteSize() const {
 }
 
 void DoubleValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.DoubleValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const DoubleValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const DoubleValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.DoubleValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.DoubleValue)
     MergeFrom(*source);
   }
 }
 
 void DoubleValue::MergeFrom(const DoubleValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.DoubleValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -493,12 +499,14 @@ void DoubleValue::MergeFrom(const DoubleValue& from) {
 }
 
 void DoubleValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.DoubleValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void DoubleValue::CopyFrom(const DoubleValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.DoubleValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -638,12 +646,13 @@ FloatValue* FloatValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void FloatValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.FloatValue)
   value_ = 0;
 }
 
 bool FloatValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.FloatValue)
   for (;;) {
@@ -710,6 +719,7 @@ void FloatValue::SerializeWithCachedSizes(
 }
 
 int FloatValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.FloatValue)
   int total_size = 0;
 
   // optional float value = 1;
@@ -724,18 +734,22 @@ int FloatValue::ByteSize() const {
 }
 
 void FloatValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.FloatValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const FloatValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const FloatValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.FloatValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.FloatValue)
     MergeFrom(*source);
   }
 }
 
 void FloatValue::MergeFrom(const FloatValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.FloatValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -743,12 +757,14 @@ void FloatValue::MergeFrom(const FloatValue& from) {
 }
 
 void FloatValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.FloatValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void FloatValue::CopyFrom(const FloatValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.FloatValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -888,12 +904,13 @@ Int64Value* Int64Value::New(::google::protobuf::Arena* arena) const {
 }
 
 void Int64Value::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Int64Value)
   value_ = GOOGLE_LONGLONG(0);
 }
 
 bool Int64Value::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Int64Value)
   for (;;) {
@@ -960,6 +977,7 @@ void Int64Value::SerializeWithCachedSizes(
 }
 
 int Int64Value::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Int64Value)
   int total_size = 0;
 
   // optional int64 value = 1;
@@ -976,18 +994,22 @@ int Int64Value::ByteSize() const {
 }
 
 void Int64Value::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Int64Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Int64Value* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Int64Value>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Int64Value)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Int64Value)
     MergeFrom(*source);
   }
 }
 
 void Int64Value::MergeFrom(const Int64Value& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Int64Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -995,12 +1017,14 @@ void Int64Value::MergeFrom(const Int64Value& from) {
 }
 
 void Int64Value::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Int64Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Int64Value::CopyFrom(const Int64Value& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Int64Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1140,12 +1164,13 @@ UInt64Value* UInt64Value::New(::google::protobuf::Arena* arena) const {
 }
 
 void UInt64Value::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.UInt64Value)
   value_ = GOOGLE_ULONGLONG(0);
 }
 
 bool UInt64Value::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.UInt64Value)
   for (;;) {
@@ -1212,6 +1237,7 @@ void UInt64Value::SerializeWithCachedSizes(
 }
 
 int UInt64Value::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.UInt64Value)
   int total_size = 0;
 
   // optional uint64 value = 1;
@@ -1228,18 +1254,22 @@ int UInt64Value::ByteSize() const {
 }
 
 void UInt64Value::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UInt64Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const UInt64Value* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const UInt64Value>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UInt64Value)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UInt64Value)
     MergeFrom(*source);
   }
 }
 
 void UInt64Value::MergeFrom(const UInt64Value& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UInt64Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -1247,12 +1277,14 @@ void UInt64Value::MergeFrom(const UInt64Value& from) {
 }
 
 void UInt64Value::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UInt64Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void UInt64Value::CopyFrom(const UInt64Value& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.UInt64Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1392,12 +1424,13 @@ Int32Value* Int32Value::New(::google::protobuf::Arena* arena) const {
 }
 
 void Int32Value::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.Int32Value)
   value_ = 0;
 }
 
 bool Int32Value::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.Int32Value)
   for (;;) {
@@ -1464,6 +1497,7 @@ void Int32Value::SerializeWithCachedSizes(
 }
 
 int Int32Value::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.Int32Value)
   int total_size = 0;
 
   // optional int32 value = 1;
@@ -1480,18 +1514,22 @@ int Int32Value::ByteSize() const {
 }
 
 void Int32Value::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.Int32Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const Int32Value* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const Int32Value>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.Int32Value)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.Int32Value)
     MergeFrom(*source);
   }
 }
 
 void Int32Value::MergeFrom(const Int32Value& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.Int32Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -1499,12 +1537,14 @@ void Int32Value::MergeFrom(const Int32Value& from) {
 }
 
 void Int32Value::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.Int32Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void Int32Value::CopyFrom(const Int32Value& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.Int32Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1644,12 +1684,13 @@ UInt32Value* UInt32Value::New(::google::protobuf::Arena* arena) const {
 }
 
 void UInt32Value::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.UInt32Value)
   value_ = 0u;
 }
 
 bool UInt32Value::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.UInt32Value)
   for (;;) {
@@ -1716,6 +1757,7 @@ void UInt32Value::SerializeWithCachedSizes(
 }
 
 int UInt32Value::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.UInt32Value)
   int total_size = 0;
 
   // optional uint32 value = 1;
@@ -1732,18 +1774,22 @@ int UInt32Value::ByteSize() const {
 }
 
 void UInt32Value::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.UInt32Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const UInt32Value* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const UInt32Value>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.UInt32Value)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.UInt32Value)
     MergeFrom(*source);
   }
 }
 
 void UInt32Value::MergeFrom(const UInt32Value& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.UInt32Value)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -1751,12 +1797,14 @@ void UInt32Value::MergeFrom(const UInt32Value& from) {
 }
 
 void UInt32Value::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.UInt32Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void UInt32Value::CopyFrom(const UInt32Value& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.UInt32Value)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -1896,12 +1944,13 @@ BoolValue* BoolValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void BoolValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.BoolValue)
   value_ = false;
 }
 
 bool BoolValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.BoolValue)
   for (;;) {
@@ -1968,6 +2017,7 @@ void BoolValue::SerializeWithCachedSizes(
 }
 
 int BoolValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.BoolValue)
   int total_size = 0;
 
   // optional bool value = 1;
@@ -1982,18 +2032,22 @@ int BoolValue::ByteSize() const {
 }
 
 void BoolValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.BoolValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const BoolValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const BoolValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.BoolValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.BoolValue)
     MergeFrom(*source);
   }
 }
 
 void BoolValue::MergeFrom(const BoolValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.BoolValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value() != 0) {
     set_value(from.value());
@@ -2001,12 +2055,14 @@ void BoolValue::MergeFrom(const BoolValue& from) {
 }
 
 void BoolValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.BoolValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void BoolValue::CopyFrom(const BoolValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.BoolValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2148,12 +2204,13 @@ StringValue* StringValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void StringValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.StringValue)
   value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 
 bool StringValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.StringValue)
   for (;;) {
@@ -2233,6 +2290,7 @@ void StringValue::SerializeWithCachedSizes(
 }
 
 int StringValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.StringValue)
   int total_size = 0;
 
   // optional string value = 1;
@@ -2249,18 +2307,22 @@ int StringValue::ByteSize() const {
 }
 
 void StringValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.StringValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const StringValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const StringValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.StringValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.StringValue)
     MergeFrom(*source);
   }
 }
 
 void StringValue::MergeFrom(const StringValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.StringValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value().size() > 0) {
     set_value(from.value());
@@ -2268,12 +2330,14 @@ void StringValue::MergeFrom(const StringValue& from) {
 }
 
 void StringValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.StringValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void StringValue::CopyFrom(const StringValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.StringValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2349,10 +2413,12 @@ void StringValue::clear_value() {
   return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* StringValue::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.StringValue.value)
   
   return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* StringValue::unsafe_arena_release_value() {
+  // @@protoc_insertion_point(field_unsafe_arena_release:google.protobuf.StringValue.value)
   GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
   
   return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
@@ -2378,7 +2444,7 @@ void StringValue::clear_value() {
   }
   value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
       value, GetArenaNoVirtual());
-  // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
+  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.StringValue.value)
 }
 
 #endif  // PROTOBUF_INLINE_NOT_IN_HEADERS
@@ -2465,12 +2531,13 @@ BytesValue* BytesValue::New(::google::protobuf::Arena* arena) const {
 }
 
 void BytesValue::Clear() {
+// @@protoc_insertion_point(message_clear_start:google.protobuf.BytesValue)
   value_.ClearToEmpty(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 
 bool BytesValue::MergePartialFromCodedStream(
     ::google::protobuf::io::CodedInputStream* input) {
-#define DO_(EXPRESSION) if (!(EXPRESSION)) goto failure
+#define DO_(EXPRESSION) if (!GOOGLE_PREDICT_TRUE(EXPRESSION)) goto failure
   ::google::protobuf::uint32 tag;
   // @@protoc_insertion_point(parse_start:google.protobuf.BytesValue)
   for (;;) {
@@ -2538,6 +2605,7 @@ void BytesValue::SerializeWithCachedSizes(
 }
 
 int BytesValue::ByteSize() const {
+// @@protoc_insertion_point(message_byte_size_start:google.protobuf.BytesValue)
   int total_size = 0;
 
   // optional bytes value = 1;
@@ -2554,18 +2622,22 @@ int BytesValue::ByteSize() const {
 }
 
 void BytesValue::MergeFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_merge_from_start:google.protobuf.BytesValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   const BytesValue* source = 
       ::google::protobuf::internal::DynamicCastToGenerated<const BytesValue>(
           &from);
   if (source == NULL) {
+  // @@protoc_insertion_point(generalized_merge_from_cast_fail:google.protobuf.BytesValue)
     ::google::protobuf::internal::ReflectionOps::Merge(from, this);
   } else {
+  // @@protoc_insertion_point(generalized_merge_from_cast_success:google.protobuf.BytesValue)
     MergeFrom(*source);
   }
 }
 
 void BytesValue::MergeFrom(const BytesValue& from) {
+// @@protoc_insertion_point(class_specific_merge_from_start:google.protobuf.BytesValue)
   if (GOOGLE_PREDICT_FALSE(&from == this)) MergeFromFail(__LINE__);
   if (from.value().size() > 0) {
     set_value(from.value());
@@ -2573,12 +2645,14 @@ void BytesValue::MergeFrom(const BytesValue& from) {
 }
 
 void BytesValue::CopyFrom(const ::google::protobuf::Message& from) {
+// @@protoc_insertion_point(generalized_copy_from_start:google.protobuf.BytesValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
 }
 
 void BytesValue::CopyFrom(const BytesValue& from) {
+// @@protoc_insertion_point(class_specific_copy_from_start:google.protobuf.BytesValue)
   if (&from == this) return;
   Clear();
   MergeFrom(from);
@@ -2654,10 +2728,12 @@ void BytesValue::clear_value() {
   return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* BytesValue::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.BytesValue.value)
   
   return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
  ::std::string* BytesValue::unsafe_arena_release_value() {
+  // @@protoc_insertion_point(field_unsafe_arena_release:google.protobuf.BytesValue.value)
   GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
   
   return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
@@ -2683,7 +2759,7 @@ void BytesValue::clear_value() {
   }
   value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
       value, GetArenaNoVirtual());
-  // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
+  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.BytesValue.value)
 }
 
 #endif  // PROTOBUF_INLINE_NOT_IN_HEADERS
diff --git a/src/google/protobuf/wrappers.pb.h b/src/google/protobuf/wrappers.pb.h
index 7dca938c..10784778 100644
--- a/src/google/protobuf/wrappers.pb.h
+++ b/src/google/protobuf/wrappers.pb.h
@@ -1048,10 +1048,12 @@ inline ::std::string* StringValue::mutable_value() {
   return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* StringValue::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.StringValue.value)
   
   return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* StringValue::unsafe_arena_release_value() {
+  // @@protoc_insertion_point(field_unsafe_arena_release:google.protobuf.StringValue.value)
   GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
   
   return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
@@ -1077,7 +1079,7 @@ inline void StringValue::unsafe_arena_set_allocated_value(
   }
   value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
       value, GetArenaNoVirtual());
-  // @@protoc_insertion_point(field_set_allocated:google.protobuf.StringValue.value)
+  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.StringValue.value)
 }
 
 // -------------------------------------------------------------------
@@ -1116,10 +1118,12 @@ inline ::std::string* BytesValue::mutable_value() {
   return value_.Mutable(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* BytesValue::release_value() {
+  // @@protoc_insertion_point(field_release:google.protobuf.BytesValue.value)
   
   return value_.Release(&::google::protobuf::internal::GetEmptyStringAlreadyInited(), GetArenaNoVirtual());
 }
 inline ::std::string* BytesValue::unsafe_arena_release_value() {
+  // @@protoc_insertion_point(field_unsafe_arena_release:google.protobuf.BytesValue.value)
   GOOGLE_DCHECK(GetArenaNoVirtual() != NULL);
   
   return value_.UnsafeArenaRelease(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
@@ -1145,7 +1149,7 @@ inline void BytesValue::unsafe_arena_set_allocated_value(
   }
   value_.UnsafeArenaSetAllocated(&::google::protobuf::internal::GetEmptyStringAlreadyInited(),
       value, GetArenaNoVirtual());
-  // @@protoc_insertion_point(field_set_allocated:google.protobuf.BytesValue.value)
+  // @@protoc_insertion_point(field_unsafe_arena_set_allocated:google.protobuf.BytesValue.value)
 }
 
 #endif  // !PROTOBUF_INLINE_NOT_IN_HEADERS
diff --git a/tests.sh b/tests.sh
index fd81b764..6a9439a5 100755
--- a/tests.sh
+++ b/tests.sh
@@ -36,6 +36,9 @@ build_cpp() {
   internal_build_cpp
   make check -j2
   cd conformance && make test_cpp && cd ..
+
+  # Verify benchmarking code can build successfully.
+  cd benchmarks && make && ./generate-datasets && cd ..
 }
 
 build_cpp_distcheck() {