Reland "Fix memory leak caused by field type in descriptor array."

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 3129 matching lines @@
 
 
 int DescriptorArray::GetFieldIndex(int descriptor_number) {
   DCHECK(GetDetails(descriptor_number).location() == kField);
   return GetDetails(descriptor_number).field_index();
 }
 
 
 HeapType* DescriptorArray::GetFieldType(int descriptor_number) {
   DCHECK(GetDetails(descriptor_number).location() == kField);
-  return HeapType::cast(GetValue(descriptor_number));
+  Object* value = GetValue(descriptor_number);
+  if (value->IsWeakCell()) {
+    if (WeakCell::cast(value)->cleared()) return HeapType::None();
+    value = WeakCell::cast(value)->value();
+  }
+  return HeapType::cast(value);
 }
 
 
 Object* DescriptorArray::GetConstant(int descriptor_number) {
   return GetValue(descriptor_number);
 }
 
 
 Object* DescriptorArray::GetCallbacksObject(int descriptor_number) {
   DCHECK(GetType(descriptor_number) == ACCESSOR_CONSTANT);
@@ skipping 4335 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_