Internalize string keys in Keyed{Store,Load}IC.

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 965 matching lines @@
   if (key->IsHeapNumber()) {
     double value = Handle<HeapNumber>::cast(key)->value();
     if (std::isnan(value)) {
       key = isolate->factory()->nan_string();
     } else {
       int int_value = FastD2I(value);
       if (value == int_value && Smi::IsValid(int_value)) {
         key = Handle<Smi>(Smi::FromInt(int_value), isolate);
       }
     }
+  } else if (key->IsString()) {
+    key = isolate->factory()->InternalizeString(Handle<String>::cast(key));
   } else if (key->IsUndefined()) {
     key = isolate->factory()->undefined_string();
   }
   return key;
 }
 
 
 Handle<Code> KeyedLoadIC::LoadElementStub(Handle<JSObject> receiver) {
   // Don't handle megamorphic property accesses for INTERCEPTORS or CALLBACKS
   // via megamorphic stubs, since they don't have a map in their relocation info
@@ skipping 1819 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal