Optimistically assume that elements IC only transition once.

src/stub-cache.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 366 matching lines @@
   Handle<Code> code =
       compiler.CompileStoreField(receiver, field_index, transition, name);
   PROFILE(isolate_, CodeCreateEvent(Logger::STORE_IC_TAG, *code, *name));
   GDBJIT(AddCode(GDBJITInterface::STORE_IC, *name, *code));
   JSObject::UpdateMapCodeCache(receiver, name, code);
   return code;
 }
 
 
 Handle<Code> StubCache::ComputeKeyedLoadOrStoreElement(
-    Handle<JSObject> receiver,
+    Handle<Map> receiver_map,
     KeyedIC::StubKind stub_kind,
     StrictModeFlag strict_mode) {
   KeyedAccessGrowMode grow_mode =
       KeyedIC::GetGrowModeFromStubKind(stub_kind);
   Code::ExtraICState extra_state =
       Code::ComputeExtraICState(grow_mode, strict_mode);
   Code::Flags flags =
       Code::ComputeMonomorphicFlags(
           stub_kind == KeyedIC::LOAD ? Code::KEYED_LOAD_IC
                                      : Code::KEYED_STORE_IC,
           NORMAL,
           extra_state);
   Handle<String> name;
   switch (stub_kind) {
     case KeyedIC::LOAD:
       name = isolate()->factory()->KeyedLoadElementMonomorphic_symbol();
       break;
     case KeyedIC::STORE_NO_TRANSITION:
       name = isolate()->factory()->KeyedStoreElementMonomorphic_symbol();
       break;
     case KeyedIC::STORE_AND_GROW_NO_TRANSITION:
       name = isolate()->factory()->KeyedStoreAndGrowElementMonomorphic_symbol();
       break;
     default:
       UNREACHABLE();
       break;
   }
-  Handle<Map> receiver_map(receiver->map());
   Handle<Object> probe(receiver_map->FindInCodeCache(*name, flags));
   if (probe->IsCode()) return Handle<Code>::cast(probe);
 
   Handle<Code> code;
   switch (stub_kind) {
     case KeyedIC::LOAD: {
       KeyedLoadStubCompiler compiler(isolate_);
       code = compiler.CompileLoadElement(receiver_map);
       break;
     }
@@ skipping 14 matching lines @@
       break;
   }
 
   ASSERT(!code.is_null());
 
   if (stub_kind == KeyedIC::LOAD) {
     PROFILE(isolate_, CodeCreateEvent(Logger::KEYED_LOAD_IC_TAG, *code, 0));
   } else {
     PROFILE(isolate_, CodeCreateEvent(Logger::KEYED_STORE_IC_TAG, *code, 0));
   }
-  JSObject::UpdateMapCodeCache(receiver, name, code);
+  Map::UpdateCodeCache(receiver_map, name, code);
   return code;
 }
 
 
 Handle<Code> StubCache::ComputeStoreNormal(StrictModeFlag strict_mode) {
   return (strict_mode == kStrictMode)
       ? isolate_->builtins()->Builtins::StoreIC_Normal_Strict()
       : isolate_->builtins()->Builtins::StoreIC_Normal();
 }
 
@@ skipping 1064 matching lines @@
           Handle<FunctionTemplateInfo>(
               FunctionTemplateInfo::cast(signature->receiver()));
     }
   }
 
   is_simple_api_call_ = true;
 }
 
 
 } }  // namespace v8::internal