Implement a heap profiler for the Dart managed heap.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
diff --git a/runtime/vm/raw_object.h b/runtime/vm/raw_object.h
index 3ed5eb4a45b707def96b9198aea16a633a93fff9..e63eaaf0fcee8a69ed90e947d7725c7cfd9ecf5c 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -343,6 +343,7 @@ class RawObject {
   friend class Api;
   friend class Array;
   friend class Heap;
+  friend class HeapProfiler;
   friend class MarkingVisitor;
   friend class Object;
   friend class RawInstructions;
@@ -387,17 +388,18 @@ class RawClass : public RawObject {
   }
 
   cpp_vtable handle_vtable_;
-  intptr_t instance_size_;
+  intptr_t instance_size_;  // Size if fixed length or 0 if variable length.
   ObjectKind instance_kind_;
   intptr_t id_;  // Class Id, also index in the class table.
   intptr_t type_arguments_instance_field_offset_;  // May be kNoTypeArguments.
-  intptr_t next_field_offset_;  // Offset of then next instance field.
+  intptr_t next_field_offset_;  // Offset of the next instance field.
   intptr_t num_native_fields_;  // Number of native fields in class.
   intptr_t token_index_;
   int8_t class_state_;  // Of type ClassState.
   bool is_const_;
   bool is_interface_;
 
+  friend class HeapProfiler;
   friend class Object;
   friend class RawInstance;
   friend class RawInstructions;
@@ -490,6 +492,8 @@ class RawInstantiatedType : public RawAbstractType {
 class RawAbstractTypeArguments : public RawObject {
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(AbstractTypeArguments);
+
+  friend class HeapProfiler;
 };
 
 
@@ -590,6 +594,8 @@ class RawField : public RawObject {
   bool is_static_;
   bool is_final_;
   bool has_initializer_;
+
+  friend class HeapProfiler;
 };
 
 
@@ -1008,6 +1014,8 @@ class RawString : public RawInstance {
   RawSmi* length_;
   RawSmi* hash_;
   RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->hash_); }
+
+  friend class HeapProfiler;
 };
 
 
@@ -1017,6 +1025,7 @@ class RawOneByteString : public RawString {
   // Variable length data follows here.
   uint8_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1027,6 +1036,7 @@ class RawTwoByteString : public RawString {
   // Variable length data follows here.
   uint16_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1037,6 +1047,7 @@ class RawFourByteString : public RawString {
   // Variable length data follows here.
   uint32_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1110,10 +1121,11 @@ class RawArray : public RawInstance {
     return reinterpret_cast<RawObject**>(&ptr()->data()[length - 1]);
   }
 
+  friend class GrowableObjectArray;
+  friend class HeapProfiler;
   friend class RawCode;
   friend class RawImmutableArray;
   friend class SnapshotReader;
-  friend class GrowableObjectArray;
 };
 
 
@@ -1148,6 +1160,8 @@ class RawByteArray : public RawInstance {
   RawObject** from() { return reinterpret_cast<RawObject**>(&ptr()->length_); }
   RawSmi* length_;
   RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->length_); }
+
+  friend class HeapProfiler;
 };
 
 
@@ -1156,6 +1170,8 @@ class RawInt8Array: public RawByteArray {
 
   // Variable length data follows here.
   int8_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1164,6 +1180,8 @@ class RawUint8Array: public RawByteArray {
 
   // Variable length data follows here.
   uint8_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1172,6 +1190,8 @@ class RawInt16Array: public RawByteArray {
 
   // Variable length data follows here.
   int16_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1180,6 +1200,8 @@ class RawUint16Array: public RawByteArray {
 
   // Variable length data follows here.
   uint16_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1188,6 +1210,8 @@ class RawInt32Array: public RawByteArray {
 
   // Variable length data follows here.
   int32_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1196,6 +1220,8 @@ class RawUint32Array: public RawByteArray {
 
   // Variable length data follows here.
   uint32_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1204,6 +1230,8 @@ class RawInt64Array: public RawByteArray {
 
   // Variable length data follows here.
   int64_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1212,6 +1240,8 @@ class RawUint64Array: public RawByteArray {
 
   // Variable length data follows here.
   uint64_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1220,6 +1250,8 @@ class RawFloat32Array: public RawByteArray {
 
   // Variable length data follows here.
   float data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1228,6 +1260,8 @@ class RawFloat64Array: public RawByteArray {
 
   // Variable length data follows here.
   double data_[0];
+
+  friend class HeapProfiler;

[turnidge, 2012/06/12 17:02:19]

I'm wondering if it makes sense to add this friend decl to one of the macros. 
What do you think?

[cshapiro, 2012/06/14 00:08:36]

I think that is a good idea.  I have pulled this up into a HEAP_PROFILER_SUPPORT
macro.  It cleans up the diff nicely.

 };