- Remember the fact that an object has been added to the

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 22083)
+++ runtime/vm/object.cc	(working copy)
@@ -1260,6 +1260,7 @@
       RawObject* raw_obj = *curr;
       if (raw_obj->IsHeapObject() && raw_obj->IsNewObject()) {
         uword ptr = reinterpret_cast<uword>(old_obj_);
+        old_obj_->SetRememberedBit();
         isolate()->store_buffer()->AddPointer(ptr);
         // Remembered this object. There is no need to continue searching.
         return;
@@ -1291,7 +1292,7 @@
   RawObject* raw_obj = Object::Allocate(cls.id(), size, space);
   NoGCScope no_gc;
   memmove(raw_obj->ptr(), src.raw()->ptr(), size);
-  if (space == Heap::kOld) {
+  if ((space == Heap::kOld) && !raw_obj->IsRemembered()) {
     StoreBufferUpdateVisitor visitor(Isolate::Current(), raw_obj);
     raw_obj->VisitPointers(&visitor);
   }