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 4d67bb099d9d41da868d89a0a99324d1c44ca83b..3128cf86960b736db897acd370d6cad653fcd459 100644
--- a/runtime/vm/raw_object.h
+++ b/runtime/vm/raw_object.h
@@ -341,6 +341,7 @@ class RawObject {
   friend class Api;
   friend class Array;
   friend class Heap;
+  friend class HeapProfiler;
   friend class MarkingVisitor;
   friend class Object;
   friend class RawInstructions;
@@ -385,17 +386,18 @@ 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 index_;  // 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;
@@ -488,6 +490,8 @@ class RawInstantiatedType : public RawAbstractType {
 class RawAbstractTypeArguments : public RawObject {
  private:
   RAW_HEAP_OBJECT_IMPLEMENTATION(AbstractTypeArguments);
+
+  friend class HeapProfiler;
 };
 
 
@@ -588,6 +592,8 @@ class RawField : public RawObject {
   bool is_static_;
   bool is_final_;
   bool has_initializer_;
+
+  friend class HeapProfiler;
 };
 
 
@@ -1004,6 +1010,8 @@ class RawString : public RawInstance {
   RawSmi* length_;
   RawSmi* hash_;
   RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->hash_); }
+
+  friend class HeapProfiler;
 };
 
 
@@ -1013,6 +1021,7 @@ class RawOneByteString : public RawString {
   // Variable length data follows here.
   uint8_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1023,6 +1032,7 @@ class RawTwoByteString : public RawString {
   // Variable length data follows here.
   uint16_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1033,6 +1043,7 @@ class RawFourByteString : public RawString {
   // Variable length data follows here.
   uint32_t data_[0];
 
+  friend class HeapProfiler;
   friend class SnapshotReader;
 };
 
@@ -1106,10 +1117,11 @@ 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;
 };
 
 
@@ -1144,6 +1156,8 @@ 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;
 };
 
 
@@ -1152,6 +1166,8 @@ class RawInt8Array: public RawByteArray {
 
   // Variable length data follows here.
   int8_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1160,6 +1176,8 @@ class RawUint8Array: public RawByteArray {
 
   // Variable length data follows here.
   uint8_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1168,6 +1186,8 @@ class RawInt16Array: public RawByteArray {
 
   // Variable length data follows here.
   int16_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1176,6 +1196,8 @@ class RawUint16Array: public RawByteArray {
 
   // Variable length data follows here.
   uint16_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1184,6 +1206,8 @@ class RawInt32Array: public RawByteArray {
 
   // Variable length data follows here.
   int32_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1192,6 +1216,8 @@ class RawUint32Array: public RawByteArray {
 
   // Variable length data follows here.
   uint32_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1200,6 +1226,8 @@ class RawInt64Array: public RawByteArray {
 
   // Variable length data follows here.
   int64_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1208,6 +1236,8 @@ class RawUint64Array: public RawByteArray {
 
   // Variable length data follows here.
   uint64_t data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1216,6 +1246,8 @@ class RawFloat32Array: public RawByteArray {
 
   // Variable length data follows here.
   float data_[0];
+
+  friend class HeapProfiler;
 };
 
 
@@ -1224,6 +1256,8 @@ class RawFloat64Array: public RawByteArray {
 
   // Variable length data follows here.
   double data_[0];
+
+  friend class HeapProfiler;
 };