Avoid duplicate lookups when Get+Creating identity hashes

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 1031 matching lines @@
 }
 
 
 bool Object::HasSpecificClassOf(String* name) {
   return this->IsJSObject() && (JSObject::cast(this)->class_name() == name);
 }
 
 MaybeHandle<Object> Object::GetProperty(Handle<Object> object,
                                         Handle<Name> name) {
   LookupIterator it(object, name);
+  if (!it.IsFound()) return it.factory()->undefined_value();
   return GetProperty(&it);
 }
 
 MaybeHandle<Object> Object::GetElement(Isolate* isolate, Handle<Object> object,
                                        uint32_t index) {
   LookupIterator it(isolate, object, index);
+  if (!it.IsFound()) return it.factory()->undefined_value();
   return GetProperty(&it);
 }
 
+Handle<Object> JSReceiver::GetDataProperty(Handle<JSReceiver> object,
+                                           Handle<Name> name) {
+  LookupIterator it(object, name,
+                    LookupIterator::PROTOTYPE_CHAIN_SKIP_INTERCEPTOR);
+  if (!it.IsFound()) return it.factory()->undefined_value();
+  return GetDataProperty(&it);
+}
 
 MaybeHandle<Object> Object::SetElement(Isolate* isolate, Handle<Object> object,
                                        uint32_t index, Handle<Object> value,
                                        LanguageMode language_mode) {
   LookupIterator it(isolate, object, index);
   MAYBE_RETURN_NULL(
       SetProperty(&it, value, language_mode, MAY_BE_STORE_FROM_KEYED));
   return value;
 }
 
@@ skipping 6677 matching lines @@
 #undef WRITE_INT64_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_OBJECTS_INL_H_