Apply Daniel's patch for array index strings.

src/objects.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 3081 matching lines @@
 
   // Limits on sizes of different types of strings.
   static const int kMaxShortStringSize = 255;
   static const int kMaxMediumStringSize = 65535;
 
   static const int kMaxArrayIndexSize = 10;
 
   // Max ascii char code.
   static const int kMaxAsciiCharCode = unibrow::Utf8::kMaxOneByteChar;
 
-  // Minimum lenth for a cons or sliced string.
+  // Minimum length for a cons or sliced string.
   static const int kMinNonFlatLength = 13;
 
   // Mask constant for checking if a string has a computed hash code
   // and if it is an array index.  The least significant bit indicates
   // whether a hash code has been computed.  If the hash code has been
   // computed the 2nd bit tells whether the string can be used as an
   // array index.
   static const int kHashComputedMask = 1;
   static const int kIsArrayIndexMask = 1 << 1;
   static const int kNofLengthBitFields = 2;
 
+  // Array index strings this short can keep their index in the hash
+  // field.
+  static const int kMaxCachedArrayIndexLength = 6;
+
   // Shift constants for retriving length and hash code from
   // length/hash field.
   static const int kHashShift = kNofLengthBitFields;
   static const int kShortLengthShift = 3 * kBitsPerByte;
   static const int kMediumLengthShift = 2 * kBitsPerByte;
   static const int kLongLengthShift = kHashShift;
 
-
   // Limit for truncation in short printing.
   static const int kMaxShortPrintLength = 1024;
 
   // Support for regular expressions.
   const uc16* GetTwoByteData();
   const uc16* GetTwoByteData(unsigned start);
 
   // Support for StringInputBuffer
   static const unibrow::byte* ReadBlock(String* input,
                                         unibrow::byte* util_buffer,
@@ skipping 919 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_