[Arguments] Introduce a new backing store for non-strict arguments objects.

src/ic.cc

 // Copyright 2006-2009 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 1235 matching lines @@
       if (attr == ABSENT && IsContextual(object)) {
         return ReferenceError("not_defined", name);
       }
       return result;
     }
 
     return object->GetProperty(*object, &lookup, *name, &attr);
   }
 
   // Do not use ICs for objects that require access checks (including
-  // the global object).
+  // the global object) nor for non-strict arguments objects.
   bool use_ic = FLAG_use_ic && !object->IsAccessCheckNeeded();
+  if (use_ic && object->IsJSObject()) {
+    Heap* heap = Handle<JSObject>::cast(object)->GetHeap();
+    Map* elements_map = Handle<JSObject>::cast(object)->elements()->map();
+    use_ic = (elements_map != heap->non_strict_arguments_elements_map());
+  }
 
   if (use_ic) {
     Code* stub = generic_stub();
     if (state == UNINITIALIZED) {
       if (object->IsString() && key->IsNumber()) {
         stub = string_stub();
       } else if (object->IsJSObject()) {
         Handle<JSObject> receiver = Handle<JSObject>::cast(object);
         if (receiver->HasExternalArrayElements()) {
           MaybeObject* probe =
@@ skipping 1108 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal