4 files changed, 13 insertions, 7 deletions
diff --git a/src/google/protobuf/io/coded_stream.h b/src/google/protobuf/io/coded_stream.h
index 361c406b..cb1869a7 100644
--- a/src/google/protobuf/io/coded_stream.h
+++ b/src/google/protobuf/io/coded_stream.h
@@ -1035,7 +1035,7 @@ inline const uint8* CodedInputStream::ExpectTagFromArray(
 inline void CodedInputStream::GetDirectBufferPointerInline(const void** data,
                                                            int* size) {
   *data = buffer_;
-  *size = buffer_end_ - buffer_;
+  *size = static_cast<int>(buffer_end_ - buffer_);
 }
 
 inline bool CodedInputStream::ExpectAtEnd() {
@@ -1231,7 +1231,7 @@ inline MessageFactory* CodedInputStream::GetExtensionFactory() {
 }
 
 inline int CodedInputStream::BufferSize() const {
-  return buffer_end_ - buffer_;
+  return static_cast<int>(buffer_end_ - buffer_);
 }
 
 inline CodedInputStream::CodedInputStream(ZeroCopyInputStream* input)
diff --git a/src/google/protobuf/map.h b/src/google/protobuf/map.h
index 52fba603..4bd76f25 100644
--- a/src/google/protobuf/map.h
+++ b/src/google/protobuf/map.h
@@ -546,7 +546,9 @@ class Map {
     }
 
 #if __cplusplus >= 201103L && !defined(GOOGLE_PROTOBUF_OS_APPLE) && \
-    !defined(GOOGLE_PROTOBUF_OS_NACL) && !defined(GOOGLE_PROTOBUF_OS_ANDROID)
+    !defined(GOOGLE_PROTOBUF_OS_NACL) &&                            \
+    !defined(GOOGLE_PROTOBUF_OS_ANDROID) &&                         \
+    !defined(GOOGLE_PROTOBUF_OS_EMSCRIPTEN)
     template<class NodeType, class... Args>
     void construct(NodeType* p, Args&&... args) {
       new (static_cast<void*>(p)) NodeType(std::forward<Args>(args)...);
diff --git a/src/google/protobuf/stubs/platform_macros.h b/src/google/protobuf/stubs/platform_macros.h
index 338d22f0..5cde8f4e 100644
--- a/src/google/protobuf/stubs/platform_macros.h
+++ b/src/google/protobuf/stubs/platform_macros.h
@@ -97,6 +97,8 @@ GOOGLE_PROTOBUF_PLATFORM_ERROR
 #if TARGET_OS_IPHONE
 #define GOOGLE_PROTOBUF_OS_IPHONE
 #endif
+#elif defined(__EMSCRIPTEN__)
+#define GOOGLE_PROTOBUF_OS_EMSCRIPTEN
 #elif defined(__native_client__)
 #define GOOGLE_PROTOBUF_OS_NACL
 #elif defined(sun)
diff --git a/src/google/protobuf/wire_format_lite_inl.h b/src/google/protobuf/wire_format_lite_inl.h
index 991c3d04..b1c477d1 100644
--- a/src/google/protobuf/wire_format_lite_inl.h
+++ b/src/google/protobuf/wire_format_lite_inl.h
@@ -835,12 +835,14 @@ inline int WireFormatLite::EnumSize(int value) {
 }
 
 inline int WireFormatLite::StringSize(const string& value) {
-  return io::CodedOutputStream::VarintSize32(value.size()) +
-         value.size();
+  return static_cast<int>(
+      io::CodedOutputStream::VarintSize32(static_cast<uint32>(value.size())) +
+      value.size());
 }
 inline int WireFormatLite::BytesSize(const string& value) {
-  return io::CodedOutputStream::VarintSize32(value.size()) +
-         value.size();
+  return static_cast<int>(
+      io::CodedOutputStream::VarintSize32(static_cast<uint32>(value.size())) +
+      value.size());
 }