A brand new, fast classfile parser.

Try it: ./tools/dump-class ./build/quick/classes

The output is intended to be easy to filter on the command line.
This is a starting point for lots of interesting bytecode analysis
for which we have waited too long.

Example.  All generic signatures we produce.

  // almost 20K classfiles
  % find build/quick/classes -name '*.class' |wc -l
      18519

  // fully parsed in 6 seconds
  tools/dump-class build/quick/classes |grep "^  signature" | wc -l
      50802

  real	0m6.230s

It's designed to be easy to make faster if you don't care about
particular classfile bits; you can override those methods to jump
forward in the input stream rather than building a structure.
For just a little sampling, here are our most frequently
repeated name/signature combinations.

194   signature               <init>  ()V   // this one is weird, wonder why there's a generic signature
115   signature    $div$colon$bslash  <A1:Ljava/lang/Object;>(TA1;Lscala/Function2<TA1;TA1;TA1;>;)TA1;
105   signature          applyOrElse  <A1:Ljava/lang/Object;B1:Ljava/lang/Object;>(TA1;Lscala/Function1<TA1;TB1;>;)TB1;
103   signature                 view  ()Ljava/lang/Object;
101   signature                toSet  <B:Ljava/lang/Object;>()Lscala/collection/immutable/Set<TB;>;

And the top five name/descriptor combinations.

11170   descriptor           <clinit>  ()V
10155   descriptor   serialVersionUID  J
7130   descriptor              apply  (Ljava/lang/Object;)Ljava/lang/Object;
3028   descriptor              apply  ()Ljava/lang/Object;
2426   descriptor             <init>  ()V

4 files changed, 116 insertions, 0 deletions

diff --git a/test/files/run/inner-parse.check b/test/files/run/inner-parse.check
new file mode 100644
index 0000000000..87ea9ddeb5
--- /dev/null
+++ b/test/files/run/inner-parse.check
@@ -0,0 +1,86 @@
+file Test$$anonfun$main$1.class
+class Test$$anonfun$main$1 extends scala.runtime.AbstractFunction1$mcVL$sp
+  interface                                        scala.Serializable
+  inner/anon                                       anonymous class: Test$$anonfun$main$1
+  descriptor                             <clinit>  ()V
+  descriptor                                apply  (Lscala/Tuple2;)V
+  descriptor                                apply  (Ljava/lang/Object;)Ljava/lang/Object;
+  descriptor                                cwd$1  Ljava/lang/String;
+  descriptor                     serialVersionUID  J
+  descriptor                               <init>  (Ljava/lang/String;)V
+  signature                                 apply  (Lscala/Tuple2<Ljava/lang/String;Lscala/reflect/internal/JvmClassInfo;>;)V
+
+file Test$.class
+class Test$ extends java.lang.Object
+  inner/anon                                       anonymous class: Test$$anonfun$main$1
+  descriptor                             <clinit>  ()V
+  descriptor                              MODULE$  LTest$;
+  descriptor                                 main  ([Ljava/lang/String;)V
+  descriptor                               <init>  ()V
+
+file Test.class
+class Test extends java.lang.Object
+  inner/anon                                       anonymous class: Test$$anonfun$main$1
+  descriptor                                 main  ([Ljava/lang/String;)V
+
+file j/J_1$B$C$D.class
+class j.J_1$B$C$D extends java.lang.Object
+  inner                                         B  j.J_1$B in j.J_1
+  inner                                         C  j.J_1$B$C in j.J_1$B
+  inner/enclosing                               D  enclosing class: j.J_1$B$C
+  descriptor                               <init>  (Lj/J_1$B$C;)V
+  descriptor                               this$2  Lj/J_1$B$C;
+
+file j/J_1$B$C.class
+class j.J_1$B$C extends java.lang.Object
+  inner                                         B  j.J_1$B in j.J_1
+  inner/enclosing                               C  enclosing class: j.J_1$B
+  inner/nested                                  D  member class: j.J_1$B$C$D
+  descriptor                               <init>  (Lj/J_1$B;)V
+  descriptor                               this$1  Lj/J_1$B;
+
+file j/J_1$B.class
+class j.J_1$B extends java.lang.Object
+  inner/enclosing                               B  enclosing class: j.J_1
+  inner/nested                                  C  member class: j.J_1$B$C
+  descriptor                               <init>  (Lj/J_1;)V
+  descriptor                               this$0  Lj/J_1;
+
+file j/J_1.class
+class j.J_1 extends java.lang.Object
+  interface                                        java.util.RandomAccess
+  inner/nested                                  B  member class: j.J_1$B
+  descriptor                               <init>  ()V
+
+file s/J_1$B$C$D.class
+class s.J_1$B$C$D extends java.lang.Object
+  inner                                         B  s.J_1$B in s.J_1
+  inner                                         C  s.J_1$B$C in s.J_1$B
+  inner/enclosing                               D  enclosing class: s.J_1$B$C
+  descriptor                               $outer  Ls/J_1$B$C;
+  descriptor                  s$J_1$B$C$D$$$outer  ()Ls/J_1$B$C;
+  descriptor                               <init>  (Ls/J_1$B$C;)V
+
+file s/J_1$B$C.class
+class s.J_1$B$C extends java.lang.Object
+  inner                                         B  s.J_1$B in s.J_1
+  inner/enclosing                               C  enclosing class: s.J_1$B
+  inner/nested                                  D  member class: s.J_1$B$C$D
+  descriptor                               $outer  Ls/J_1$B;
+  descriptor                    s$J_1$B$C$$$outer  ()Ls/J_1$B;
+  descriptor                               <init>  (Ls/J_1$B;)V
+
+file s/J_1$B.class
+class s.J_1$B extends java.lang.Object
+  inner/enclosing                               B  enclosing class: s.J_1
+  inner/nested                                  C  member class: s.J_1$B$C
+  descriptor                               $outer  Ls/J_1;
+  descriptor                      s$J_1$B$$$outer  ()Ls/J_1;
+  descriptor                               <init>  (Ls/J_1;)V
+
+file s/J_1.class
+class s.J_1 extends java.lang.Object
+  interface                                        java.util.RandomAccess
+  inner/nested                                  B  member class: s.J_1$B
+  descriptor                               <init>  ()V
+
diff --git a/test/files/run/inner-parse/J_1.java b/test/files/run/inner-parse/J_1.java
new file mode 100644
index 0000000000..920ab951ab
--- /dev/null
+++ b/test/files/run/inner-parse/J_1.java
@@ -0,0 +1,9 @@
+package j;
+
+public class J_1 implements java.util.RandomAccess {  // "random" marker interface
+  class B {
+    class C {
+      class D { }
+    }
+  }
+}
diff --git a/test/files/run/inner-parse/S_2.scala b/test/files/run/inner-parse/S_2.scala
new file mode 100644
index 0000000000..fd144a40b7
--- /dev/null
+++ b/test/files/run/inner-parse/S_2.scala
@@ -0,0 +1,9 @@
+package s;
+
+class J_1 extends java.util.RandomAccess {
+  class B {
+    class C {
+      class D { }
+    }
+  }
+}
diff --git a/test/files/run/inner-parse/S_3.scala b/test/files/run/inner-parse/S_3.scala
new file mode 100644
index 0000000000..296a651460
--- /dev/null
+++ b/test/files/run/inner-parse/S_3.scala
@@ -0,0 +1,12 @@
+import scala.reflect.internal.JvmClassInfo
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val cwd = sys.props("partest.output")
+    
+    for ((f, info) <- JvmClassInfo.classInfoList(cwd)) {
+      println("file " + f.stripPrefix(cwd + "/"))
+      println(info)
+    }
+  }
+}