Add a flag to over approximate the weak closure during GC

src/heap/heap.h

Index: src/heap/heap.h
diff --git a/src/heap/heap.h b/src/heap/heap.h
index ceae148bbc1862e51a5133356ecc4ed7f3db2b73..1d172bbac9e7aa337a835d82bd5ca0084fa45e9d 100644
--- a/src/heap/heap.h
+++ b/src/heap/heap.h
@@ -754,6 +754,11 @@ class Heap {
   // Making the heap iterable requires us to abort incremental marking.
   static const int kMakeHeapIterableMask = kAbortIncrementalMarkingMask;
 
+  // Invoked when GC was requested via the stack guard.
+  void HandleGCRequest();
+
+  void OverApproximateWeakClosure(const char* gc_reason);

[Hannes Payer (out of office), 2015/02/03 17:40:11]

Please add a comment here how the over approximation works.

[jochen (gone - plz use gerrit), 2015/02/09 16:03:43]

done

+
   // Performs a full garbage collection.  If (flags & kMakeHeapIterableMask) is
   // non-zero, then the slower precise sweeper is used, which leaves the heap
   // in a state where we can iterate over the heap visiting all objects.