Fix the logic that should ensure that a string cannot have

src/objects.h

 // Copyright 2011 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 6441 matching lines @@
   // 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 kHashNotComputedMask = 1;
   static const int kIsNotArrayIndexMask = 1 << 1;
   static const int kNofHashBitFields = 2;
 
   // Shift constant retrieving hash code from hash field.
   static const int kHashShift = kNofHashBitFields;
 
+  // Only these bits are relevant in the hash, since the top two are shifted
+  // out.
+  static const uint32_t kHashBitMask = 0xffffffffu >> kHashShift;
+
   // Array index strings this short can keep their index in the hash
   // field.
   static const int kMaxCachedArrayIndexLength = 7;
 
   // For strings which are array indexes the hash value has the string length
   // mixed into the hash, mainly to avoid a hash value of zero which would be
   // the case for the string '0'. 24 bits are used for the array index value.
   static const int kArrayIndexValueBits = 24;
   static const int kArrayIndexLengthBits =
       kBitsPerInt - kArrayIndexValueBits - kNofHashBitFields;
@@ skipping 1539 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_