Reimplemented the KeyedLookupCache to speed up access.

src/heap.cc

 // Copyright 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 482 matching lines @@
   Shrink();
 
   Counters::objs_since_last_full.Set(0);
   context_disposed_pending_ = false;
 }
 
 
 void Heap::MarkCompactPrologue(bool is_compacting) {
   // At any old GC clear the keyed lookup cache to enable collection of unused
   // maps.
-  ClearKeyedLookupCache();
+  KeyedLookupCache::Clear();
 
   CompilationCache::MarkCompactPrologue();
 
   Top::MarkCompactPrologue(is_compacting);
   ThreadManager::MarkCompactPrologue(is_compacting);
 }
 
 
 void Heap::MarkCompactEpilogue(bool is_compacting) {
   Top::MarkCompactEpilogue(is_compacting);
@@ skipping 843 matching lines @@
 
   // Allocate cache for external strings pointing to native source code.
   obj = AllocateFixedArray(Natives::GetBuiltinsCount());
   if (obj->IsFailure()) return false;
   natives_source_cache_ = FixedArray::cast(obj);
 
   // Handling of script id generation is in Factory::NewScript.
   last_script_id_ = undefined_value();
 
   // Initialize keyed lookup cache.
-  ClearKeyedLookupCache();
+  KeyedLookupCache::Clear();
 
   // Initialize compilation cache.
   CompilationCache::Clear();
 
   return true;
 }
 
 
 static inline int double_get_hash(double d) {
   DoubleRepresentation rep(d);
@@ skipping 2093 matching lines @@
     case SCAVENGER:
       return "Scavenge";
     case MARK_COMPACTOR:
       return MarkCompactCollector::HasCompacted() ? "Mark-compact"
                                                   : "Mark-sweep";
   }
   return "Unknown GC";
 }
 
 
+int KeyedLookupCache::Hash(Map* map, String* name) {
+  // Uses only lower 32 bits if pointers are larger.
+  uintptr_t addr_hash =
+      static_cast<uint32_t>(reinterpret_cast<uintptr_t>(map)) >> 2;
+  return (addr_hash ^ name->Hash()) % kLength;
+}
+
+
+int KeyedLookupCache::Lookup(Map* map, String* name) {
+  int index = Hash(map, name);
+  Key& key = keys_[index];
+  if ((key.map == map) && key.name->Equals(name)) {
+    return field_offsets_[index];
+  }
+  return -1;
+}
+
+
+void KeyedLookupCache::Update(Map* map, String* name, int field_offset) {
+  String* symbol;
+  if (Heap::LookupSymbolIfExists(name, &symbol)) {
+    int index = Hash(map, symbol);
+    Key& key = keys_[index];
+    key.map = map;
+    key.name = symbol;
+    field_offsets_[index] = field_offset;
+  }
+}
+
+
+void KeyedLookupCache::Clear() {
+  for (int index = 0; index < kLength; index++) keys_[index].map = NULL;
+}
+
+KeyedLookupCache::Key KeyedLookupCache::keys_[KeyedLookupCache::kLength];
+
+int KeyedLookupCache::field_offsets_[KeyedLookupCache::kLength];
+
+
 #ifdef DEBUG
 bool Heap::GarbageCollectionGreedyCheck() {
   ASSERT(FLAG_gc_greedy);
   if (Bootstrapper::IsActive()) return true;
   if (disallow_allocation_failure()) return true;
   return CollectGarbage(0, NEW_SPACE);
 }
 #endif
 
 } }  // namespace v8::internal