Improve load IC so it can call a native accessor even if the holder is

src/ic.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 971 matching lines @@
           // applicable.
           if (!holder.is_identical_to(receiver)) return;
           code = isolate()->stub_cache()->ComputeLoadNormal();
         }
         break;
       case CALLBACKS: {
         Handle<Object> callback(lookup->GetCallbackObject());
         if (callback->IsAccessorInfo()) {
           Handle<AccessorInfo> info = Handle<AccessorInfo>::cast(callback);
           if (v8::ToCData<Address>(info->getter()) == 0) return;
-          if (!holder->HasFastProperties()) return;

[Michael Starzinger, 2012/08/13 17:47:16]

What about the KeyedLoadIC?

           if (!info->IsCompatibleReceiver(*receiver)) return;
           code = isolate()->stub_cache()->ComputeLoadCallback(
               name, receiver, holder, info);
         } else if (callback->IsAccessorPair()) {
           Handle<Object> getter(Handle<AccessorPair>::cast(callback)->getter());
           if (!getter->IsJSFunction()) return;
           if (holder->IsGlobalObject()) return;
-          if (!holder->HasFastProperties()) return;

[Michael Starzinger, 2012/08/13 17:47:16]

Why can we generate a JavaScript getter call for a slow holder now? We are not
doing any positive dictionary lookup there.

           code = isolate()->stub_cache()->ComputeLoadViaGetter(
               name, receiver, holder, Handle<JSFunction>::cast(getter));
         } else {
           ASSERT(callback->IsForeign());
           // No IC support for old-style native accessors.
           return;
         }
         break;
       }
       case INTERCEPTOR:
@@ skipping 1688 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal