Eliminate special keyed load string stub in favor of uniform handlers.

src/ic/handler-compiler.cc

 // Copyright 2014 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/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
 #include "src/ic/ic.h"
 #include "src/ic/ic-inl.h"
@@ skipping 397 matching lines @@
 
 #undef __
 
 
 void ElementHandlerCompiler::CompileElementHandlers(
     MapHandleList* receiver_maps, CodeHandleList* handlers) {
   for (int i = 0; i < receiver_maps->length(); ++i) {
     Handle<Map> receiver_map = receiver_maps->at(i);
     Handle<Code> cached_stub;
 
-    if ((receiver_map->instance_type() & kNotStringTag) == 0) {
-      cached_stub = isolate()->builtins()->KeyedLoadIC_String();
+    if (receiver_map->IsStringMap()) {
+      cached_stub = LoadIndexedStringStub(isolate()).GetCode();
     } else if (receiver_map->instance_type() < FIRST_JS_RECEIVER_TYPE) {
       cached_stub = isolate()->builtins()->KeyedLoadIC_Slow();
     } else {
       bool is_js_array = receiver_map->instance_type() == JS_ARRAY_TYPE;
       ElementsKind elements_kind = receiver_map->elements_kind();
       if (receiver_map->has_indexed_interceptor()) {
         cached_stub = LoadIndexedInterceptorStub(isolate()).GetCode();
       } else if (IsSloppyArgumentsElements(elements_kind)) {
         cached_stub = KeyedLoadSloppyArgumentsStub(isolate()).GetCode();
       } else if (IsFastElementsKind(elements_kind) ||
                  IsExternalArrayElementsKind(elements_kind) ||
                  IsFixedTypedArrayElementsKind(elements_kind)) {
         cached_stub = LoadFastElementStub(isolate(), is_js_array, elements_kind)
                           .GetCode();
       } else {
         DCHECK(elements_kind == DICTIONARY_ELEMENTS);
         cached_stub = LoadDictionaryElementStub(isolate()).GetCode();
       }
     }
 
     handlers->Add(cached_stub);
   }
 }
 }
 }  // namespace v8::internal