Reimplemented the KeyedLookupCache to speed up access.

src/runtime.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 2615 matching lines @@
   // Additionally, we need to make sure that we do not cache results
   // for objects that require access checks.
   if (args[0]->IsJSObject() &&
       !args[0]->IsJSGlobalProxy() &&
       !args[0]->IsAccessCheckNeeded() &&
       args[1]->IsString()) {
     JSObject* receiver = JSObject::cast(args[0]);
     String* key = String::cast(args[1]);
     if (receiver->HasFastProperties()) {
       // Attempt to use lookup cache.
-      Object* obj = Heap::GetKeyedLookupCache();
-      if (obj->IsFailure()) return obj;
-      LookupCache* cache = LookupCache::cast(obj);
       Map* receiver_map = receiver->map();
-      int offset = cache->Lookup(receiver_map, key);
-      if (offset != LookupCache::kNotFound) {
+      int offset = KeyedLookupCache::Lookup(receiver_map, key);
+      if (offset != -1) {
         Object* value = receiver->FastPropertyAt(offset);
         return value->IsTheHole() ? Heap::undefined_value() : value;
       }
       // Lookup cache miss.  Perform lookup and update the cache if
       // appropriate.
       LookupResult result;
       receiver->LocalLookup(key, &result);
       if (result.IsProperty() && result.IsLoaded() && result.type() == FIELD) {
         int offset = result.GetFieldIndex();
-        Object* obj = cache->Put(receiver_map, key, offset);
-        if (obj->IsFailure()) return obj;
-        Heap::SetKeyedLookupCache(LookupCache::cast(obj));
+        KeyedLookupCache::Update(receiver_map, key, offset);
         Object* value = receiver->FastPropertyAt(offset);
         return value->IsTheHole() ? Heap::undefined_value() : value;
       }
     } else {
       // Attempt dictionary lookup.
       Dictionary* dictionary = receiver->property_dictionary();
       int entry = dictionary->FindStringEntry(key);
       if ((entry != DescriptorArray::kNotFound) &&
           (dictionary->DetailsAt(entry).type() == NORMAL)) {
         return dictionary->ValueAt(entry);
@@ skipping 4804 matching lines @@
   } else {
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     Counters::gc_last_resort_from_js.Increment();
     Heap::CollectAllGarbage();
   }
 }
 
 
 } }  // namespace v8::internal