Make so that array length property access uses a new IC that tracks the array map.

src/stub-cache.h

 // 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 72 matching lines @@
   Handle<Code> ComputeLoadField(Handle<String> name,
                                 Handle<JSObject> receiver,
                                 Handle<JSObject> holder,
                                 int field_index);
 
   Handle<Code> ComputeLoadCallback(Handle<String> name,
                                    Handle<JSObject> receiver,
                                    Handle<JSObject> holder,
                                    Handle<AccessorInfo> callback);
 
+  Handle<Code> ComputeLoadArrayLength(Handle<String> name,
+                                      Handle<JSObject> receiver,
+                                      Handle<JSObject> holder);
+
   Handle<Code> ComputeLoadViaGetter(Handle<String> name,
                                     Handle<JSObject> receiver,
                                     Handle<JSObject> holder,
                                     Handle<JSFunction> getter);
 
   Handle<Code> ComputeLoadConstant(Handle<String> name,
                                    Handle<JSObject> receiver,
                                    Handle<JSObject> holder,
                                    Handle<JSFunction> value);
 
@@ skipping 509 matching lines @@
   Handle<Code> CompileLoadField(Handle<JSObject> object,
                                 Handle<JSObject> holder,
                                 int index,
                                 Handle<String> name);
 
   Handle<Code> CompileLoadCallback(Handle<String> name,
                                    Handle<JSObject> object,
                                    Handle<JSObject> holder,
                                    Handle<AccessorInfo> callback);
 
+  static void GenerateLoadArrayLength(MacroAssembler* masm, Register holder);
+
+  Handle<Code> CompileLoadArrayLength(Handle<String> name,
+                                      Handle<JSObject> receiver,
+                                      Handle<JSObject> holder);
+
   static void GenerateLoadViaGetter(MacroAssembler* masm,
                                     Handle<JSFunction> getter);
 
   Handle<Code> CompileLoadViaGetter(Handle<String> name,
                                     Handle<JSObject> receiver,
                                     Handle<JSObject> holder,
                                     Handle<JSFunction> getter);
 
   Handle<Code> CompileLoadConstant(Handle<JSObject> object,
                                    Handle<JSObject> holder,
                                    Handle<JSFunction> value,
                                    Handle<String> name);
 
   Handle<Code> CompileLoadInterceptor(Handle<JSObject> object,
                                       Handle<JSObject> holder,
                                       Handle<String> name);
 
   Handle<Code> CompileLoadGlobal(Handle<JSObject> object,
                                  Handle<GlobalObject> holder,
                                  Handle<JSGlobalPropertyCell> cell,
                                  Handle<String> name,
                                  bool is_dont_delete);
 
  private:
-  Handle<Code> GetCode(Code::StubType type, Handle<String> name);
+  Handle<Code> GetCode(
+      Code::StubType type, Handle<String> name,
+      Code::ExtraICStateForeignCallback callbackType =
+          Code::ExtraICStateForeignCallbackNone);
 };
 
 
 class KeyedLoadStubCompiler: public StubCompiler {
  public:
   explicit KeyedLoadStubCompiler(Isolate* isolate) : StubCompiler(isolate) { }
 
   Handle<Code> CompileLoadField(Handle<String> name,
                                 Handle<JSObject> object,
                                 Handle<JSObject> holder,
@@ skipping 277 matching lines @@
   Handle<JSFunction> constant_function_;
   bool is_simple_api_call_;
   Handle<FunctionTemplateInfo> expected_receiver_type_;
   Handle<CallHandlerInfo> api_call_info_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_STUB_CACHE_H_