- Add special access for receiver as it is a frequently used operation

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
@@ skipping 3595 matching lines @@
 }
 
 
 DART_EXPORT Dart_Handle Dart_GetNativeReceiver(Dart_NativeArguments args,
                                                intptr_t* value) {
   NativeArguments* arguments = reinterpret_cast<NativeArguments*>(args);
   Isolate* isolate = arguments->isolate();
   CHECK_ISOLATE(isolate);
   ReusableObjectHandleScope reused_obj_handle(isolate);
   Object& obj = reused_obj_handle.Handle();
-  obj = arguments->NativeArgAt(0);
+  obj = arguments->NativeReceiver();
   intptr_t cid = obj.GetClassId();
   if (cid <= kNumPredefinedCids) {
     if (cid == kNullCid) {
       return Api::NewError("%s expects receiver argument to be non-null.",
                            CURRENT_FUNC);
     }
     return Api::NewError("%s expects receiver argument to be of"
                          " type Instance.", CURRENT_FUNC);
   }
   const Instance& instance = Instance::Cast(obj);
@@ skipping 657 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 }  // namespace dart