Track external allocated memory for weak persistent handles.

runtime/vm/heap.h

Index: runtime/vm/heap.h
===================================================================
--- runtime/vm/heap.h	(revision 33235)
+++ runtime/vm/heap.h	(working copy)
@@ -102,6 +102,11 @@
     return 0;
   }
 
+  // Track external data. The 'ref' pointer is only used to determine which
+  // space to use. Non-heap and VM heap objects are charged to old space.
+  void AllocateExternal(intptr_t size, RawObject* ref);
+  void FreeExternal(intptr_t size, RawObject* ref);

[siva, 2014/03/06 17:17:39]

Normally we try to avoid passing in raw pointers as parameters to functions
unless they are special functions that are invoked during GC or snapshot
writing. Why not change this API to

void AllocateExternal(intptr_t size, Space space);
void FreeExternal(intptr_t size, Space space);

[koda, 2014/03/06 22:55:07]

Done. I moved the space detection code into FinalizeablePersistentHandle. Do you
think it would make sense to have a RawObject::GetSpace/GetGeneration?

+
   // Heap contains the specified address.
   bool Contains(uword addr) const;
   bool NewContains(uword addr) const;
@@ -162,9 +167,10 @@
   // Print heap sizes.
   void PrintSizes() const;
 
-  // Return amount of memory used and capacity in a space.
+  // Return amount of memory used and capacity in a space, excluding external.
   intptr_t UsedInWords(Space space) const;
   intptr_t CapacityInWords(Space space) const;
+  intptr_t ExternalInWords(Space space) const;
   // Return the amount of GCing in microseconds.
   int64_t GCTimeInMicros(Space space) const;