Implement a heap profiler for the Dart managed heap.

runtime/vm/heap.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_HEAP_H_
 #define VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 96 matching lines @@
 
   // Initialize the heap and register it with the isolate.
   static void Init(Isolate* isolate);
 
   // Verify that all pointers in the heap point to the heap.
   bool Verify() const;
 
   // Print heap sizes.
   void PrintSizes() const;
 
+  // Generates a profile of the current and VM isolate heaps.

[turnidge, 2012/05/29 17:50:01]

Out of curiosity -- by including the VM isolate heap in all of our per-isolate
heap profiles, is there some chance tools will get a bloated sense of the
per-isolate space requirements?  Maybe this doesn't matter.

[cshapiro, 2012/06/01 04:27:02]

Based on experience, the most common use of this data will be to examine a heap
post-OOM to understand what retained storage.  In that situation it is usually
okay for the vm isolate data to be included as it will be dwarfed by the
application heap.  

I think having a snapshot of just the current isolate would be a good option to
have.  Once the profiler becomes more complete I would like to add a flag to
control whether the VM isolate contents are emitted.

+  void Profile(Dart_HeapProfileWriteCallback callback, void* stream) const;
+
  private:
   Heap();
 
   uword AllocateNew(intptr_t size);
   uword AllocateOld(intptr_t size);
   uword AllocateCode(PageSpace* space, intptr_t size);
 
   // The different spaces used for allocation.
   Scavenger* new_space_;
   PageSpace* old_space_;
@@ skipping 17 matching lines @@
  public:
   NoGCScope() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(NoGCScope);
 };
 #endif  // defined(DEBUG)
 
 }  // namespace dart
 
 #endif  // VM_HEAP_H_