Allocate a new empty number dictionary when resetting elements

src/objects.cc

 // Copyright 2013 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/v8.h"
 
 #include "src/accessors.h"
 #include "src/allocation-site-scopes.h"
 #include "src/api.h"
 #include "src/arguments.h"
@@ skipping 4393 matching lines @@
 
   object->set_properties(*fields);
   DCHECK(object->IsJSObject());
 
   // Check that it really works.
   DCHECK(object->HasFastProperties());
 }
 
 
 void JSObject::ResetElements(Handle<JSObject> object) {
-  Heap* heap = object->GetIsolate()->heap();
-  CHECK(object->map() != heap->sloppy_arguments_elements_map());
-  object->set_elements(object->map()->GetInitialElements());
+  Isolate* isolate = object->GetIsolate();
+  CHECK(object->map() != isolate->heap()->sloppy_arguments_elements_map());
+  if (object->map()->has_dictionary_elements()) {
+    Handle<SeededNumberDictionary> new_elements =
+        SeededNumberDictionary::New(isolate, 0);
+    object->set_elements(*new_elements);
+  } else {
+    object->set_elements(object->map()->GetInitialElements());
+  }
 }
 
 
 static Handle<SeededNumberDictionary> CopyFastElementsToDictionary(
     Handle<FixedArrayBase> array,
     int length,
     Handle<SeededNumberDictionary> dictionary) {
   Isolate* isolate = array->GetIsolate();
   Factory* factory = isolate->factory();
   bool has_double_elements = array->IsFixedDoubleArray();
@@ skipping 11983 matching lines @@
 #define ERROR_MESSAGES_TEXTS(C, T) T,
   static const char* error_messages_[] = {
       ERROR_MESSAGES_LIST(ERROR_MESSAGES_TEXTS)
   };
 #undef ERROR_MESSAGES_TEXTS
   return error_messages_[reason];
 }
 
 
 } }  // namespace v8::internal