Correctly materialize arguments object in Runtime_DebugEvaluate.

src/runtime.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 11531 matching lines @@
   if (scope_info->HasHeapAllocatedLocals()) {
     VariableMode mode;
     InitializationFlag init_flag;
     index = scope_info->ContextSlotIndex(
         isolate->heap()->arguments_string(), &mode, &init_flag);
     if (index != -1) {
       return Handle<Object>(function_context->get(index), isolate);
     }
   }
 
-  Handle<JSFunction> function(JSFunction::cast(frame_inspector->GetFunction()));
-  int length = frame_inspector->GetParametersCount();
-  Handle<JSObject> arguments =
-      isolate->factory()->NewArgumentsObject(function, length);
-  Handle<FixedArray> array = isolate->factory()->NewFixedArray(length);
-
-  AssertNoAllocation no_gc;
-  WriteBarrierMode mode = array->GetWriteBarrierMode(no_gc);
-  for (int i = 0; i < length; i++) {
-    array->set(i, frame_inspector->GetParameter(i), mode);
-  }
-  arguments->set_elements(*array);
-  return arguments;
+  // FunctionGetArguments can't return a non-Object.
+  return Handle<JSObject>(JSObject::cast(
+      Accessors::FunctionGetArguments(frame_inspector->GetFunction(),
+                                      NULL)->ToObjectUnchecked()), isolate);
 }
 
 
 // Compile and evaluate source for the given context.
 static MaybeObject* DebugEvaluate(Isolate* isolate,
                                   Handle<Context> context,
                                   Handle<Object> context_extension,
                                   Handle<Object> receiver,
                                   Handle<String> source) {
   if (context_extension->IsJSObject()) {
@@ skipping 1411 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal