Reland r26549 "Fix IsWeakObjectInOptimizedCode predicate to also include property cells."

src/objects-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 5224 matching lines @@
       FromAddress(Memory::Address_at(location_of_address) - Code::kHeaderSize);
 }
 
 
 bool Code::IsWeakObjectInOptimizedCode(Object* object) {
   if (!FLAG_collect_maps) return false;
   if (object->IsMap()) {
     return Map::cast(object)->CanTransition() &&
            FLAG_weak_embedded_maps_in_optimized_code;
   }
-  if (object->IsCell()) object = Cell::cast(object)->value();
+  if (object->IsCell()) {
+    object = Cell::cast(object)->value();
+  } else if (object->IsPropertyCell()) {
+    object = PropertyCell::cast(object)->value();
+  }
   if (object->IsJSObject()) {
     return FLAG_weak_embedded_objects_in_optimized_code;
   }
   if (object->IsFixedArray()) {
     // Contexts of inlined functions are embedded in optimized code.
     Map* map = HeapObject::cast(object)->map();
     Heap* heap = map->GetHeap();
     return FLAG_weak_embedded_objects_in_optimized_code &&
            map == heap->function_context_map();
   }
@@ skipping 2367 matching lines @@
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_