Support fast case for-in in Crankshaft.

src/objects.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 2394 matching lines @@
   }
 
   // TODO(1399): It should be possible to make room for bit_field3 in the map
   //             without overloading the instance descriptors field in the map
   //             (and storing it in the DescriptorArray when the map has one).
   inline int bit_field3_storage();
   inline void set_bit_field3_storage(int value);
 
   // Initialize or change the enum cache,
   // using the supplied storage for the small "bridge".
-  void SetEnumCache(FixedArray* bridge_storage, FixedArray* new_cache);
+  void SetEnumCache(FixedArray* bridge_storage,
+                    FixedArray* new_cache,
+                    Object* new_index_cache);
 
   // Accessors for fetching instance descriptor at descriptor number.
   inline String* GetKey(int descriptor_number);
   inline Object* GetValue(int descriptor_number);
   inline Smi* GetDetails(int descriptor_number);
   inline PropertyType GetType(int descriptor_number);
   inline int GetFieldIndex(int descriptor_number);
   inline JSFunction* GetConstantFunction(int descriptor_number);
   inline Object* GetCallbacksObject(int descriptor_number);
   inline AccessorDescriptor* GetCallbacks(int descriptor_number);
@@ skipping 83 matching lines @@
 
   // Constant for denoting key was not found.
   static const int kNotFound = -1;
 
   static const int kBitField3StorageIndex = 0;
   static const int kContentArrayIndex = 1;
   static const int kEnumerationIndexIndex = 2;
   static const int kFirstIndex = 3;
 
   // The length of the "bridge" to the enum cache.
-  static const int kEnumCacheBridgeLength = 2;
+  static const int kEnumCacheBridgeLength = 3;
   static const int kEnumCacheBridgeEnumIndex = 0;
   static const int kEnumCacheBridgeCacheIndex = 1;
+  static const int kEnumCacheBridgeIndicesCacheIndex = 2;
 
   // Layout description.
   static const int kBitField3StorageOffset = FixedArray::kHeaderSize;
   static const int kContentArrayOffset = kBitField3StorageOffset + kPointerSize;
   static const int kEnumerationIndexOffset = kContentArrayOffset + kPointerSize;
   static const int kFirstOffset = kEnumerationIndexOffset + kPointerSize;
 
   // Layout description for the bridge array.
   static const int kEnumCacheBridgeEnumOffset = FixedArray::kHeaderSize;
   static const int kEnumCacheBridgeCacheOffset =
@@ skipping 5770 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_