Make setting length on arrays faster.

src/builtins.h

 // Copyright 2006-2008 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 78 matching lines @@
   V(KeyedLoadIC_ExternalByteArray,          KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalUnsignedByteArray,  KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalShortArray,         KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalUnsignedShortArray, KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalIntArray,           KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalUnsignedIntArray,   KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_ExternalFloatArray,         KEYED_LOAD_IC, MEGAMORPHIC)   \
   V(KeyedLoadIC_IndexedInterceptor,         KEYED_LOAD_IC, MEGAMORPHIC)   \
                                                                           \
   V(StoreIC_Initialize,         STORE_IC, UNINITIALIZED)                  \
+  V(StoreIC_ArrayLength,        STORE_IC, MONOMORPHIC)                    \
   V(StoreIC_Megamorphic,        STORE_IC, MEGAMORPHIC)                    \
                                                                           \
   V(KeyedStoreIC_Initialize,    KEYED_STORE_IC, UNINITIALIZED)            \
   V(KeyedStoreIC_Generic,       KEYED_STORE_IC, MEGAMORPHIC)              \
   V(KeyedStoreIC_ExternalByteArray,          KEYED_STORE_IC, MEGAMORPHIC) \
   V(KeyedStoreIC_ExternalUnsignedByteArray,  KEYED_STORE_IC, MEGAMORPHIC) \
   V(KeyedStoreIC_ExternalShortArray,         KEYED_STORE_IC, MEGAMORPHIC) \
   V(KeyedStoreIC_ExternalUnsignedShortArray, KEYED_STORE_IC, MEGAMORPHIC) \
   V(KeyedStoreIC_ExternalIntArray,           KEYED_STORE_IC, MEGAMORPHIC) \
   V(KeyedStoreIC_ExternalUnsignedIntArray,   KEYED_STORE_IC, MEGAMORPHIC) \
@@ skipping 140 matching lines @@
   static void Generate_FunctionCall(MacroAssembler* masm);
   static void Generate_FunctionApply(MacroAssembler* masm);
 
   static void Generate_ArrayCode(MacroAssembler* masm);
   static void Generate_ArrayConstructCode(MacroAssembler* masm);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_BUILTINS_H_