[runtime] Fix Object.create(null) initialization order

src/runtime/runtime-object.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/bootstrapper.h"
 #include "src/debug/debug.h"
 #include "src/isolate-inl.h"
@@ skipping 229 matching lines @@
       } else {
         map = Map::CopyInitialMap(map);
         Map::SetPrototype(map, prototype, FAST_PROTOTYPE);
         PrototypeInfo::SetObjectCreateMap(info, map);
       }
     } else {
       map = Map::TransitionToPrototype(map, prototype, REGULAR_PROTOTYPE);
     }
   }
 
+  bool is_dictionary_map = map->is_dictionary_map();
+  Handle<FixedArray> object_properties;
+  if (is_dictionary_map) {
+    // Allocate the actual properties dictionay up front to avoid invalid object
+    // state.
+    object_properties =
+        NameDictionary::New(isolate, NameDictionary::kInitialCapacity);
+  }
   // Actually allocate the object.
   Handle<JSObject> object = isolate->factory()->NewJSObjectFromMap(map);
-
-  if (map->is_dictionary_map()) {
-    Handle<NameDictionary> properties =
-        NameDictionary::New(isolate, NameDictionary::kInitialCapacity);
-    object->set_properties(*properties);
+  if (is_dictionary_map) {
+    object->set_properties(*object_properties);
   }
 
   // Define the properties if properties was specified and is not undefined.
   Handle<Object> properties = args.at<Object>(1);
   if (!properties->IsUndefined(isolate)) {
     RETURN_FAILURE_ON_EXCEPTION(
         isolate, JSReceiver::DefineProperties(isolate, object, properties));
   }
 
   return *object;
@@ skipping 674 matching lines @@
   if (!success) return isolate->heap()->exception();
   MAYBE_RETURN(
       JSReceiver::CreateDataProperty(&it, value, Object::THROW_ON_ERROR),
       isolate->heap()->exception());
   return *value;
 }
 
 
 }  // namespace internal
 }  // namespace v8