Implementing weak referencing elements transition maps.

src/objects-debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 904 matching lines @@
   return true;
 }
 
 
 static bool CheckOneBackPointer(Map* current_map, Object* target) {
   return !target->IsMap() || Map::cast(target)->GetBackPointer() == current_map;
 }
 
 
 bool DescriptorArray::IsConsistentWithBackPointers(Map* current_map) {
+  Map* elements_transition = elements_transition_map();
+  if (elements_transition != NULL &&
+      !CheckOneBackPointer(current_map, elements_transition)) {
+    return false;
+  }
   for (int i = 0; i < number_of_descriptors(); ++i) {
     switch (GetType(i)) {
       case MAP_TRANSITION:
       case CONSTANT_TRANSITION:
         if (!CheckOneBackPointer(current_map, GetValue(i))) {
           return false;
         }
         break;
       case CALLBACKS: {
         Object* object = GetValue(i);
@@ skipping 75 matching lines @@
   FixedArray* proto_transitions = prototype_transitions();
   MemsetPointer(proto_transitions->data_start(),
                 GetHeap()->the_hole_value(),
                 proto_transitions->length());
 }
 
 
 #endif  // DEBUG
 
 } }  // namespace v8::internal