Allow hidden properties and implement GetIdentityHash

src/objects-inl.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 2426 matching lines @@
 
 void StringHasher::AddCharacterNoIndex(uc32 c) {
   ASSERT(!is_array_index());
   raw_running_hash_ += c;
   raw_running_hash_ += (raw_running_hash_ << 10);
   raw_running_hash_ ^= (raw_running_hash_ >> 6);
 }
 
 
 uint32_t StringHasher::GetHash() {
+  // Get the calculated raw hash value and do some more bit ops to distribute
+  // the hash further. Ensure that we never return zero as the hash value.
   uint32_t result = raw_running_hash_;
   result += (result << 3);
   result ^= (result >> 11);
   result += (result << 15);
+  if (result == 0) {
+    result = 27;
+  }
   return result;
 }
 
 
 bool String::AsArrayIndex(uint32_t* index) {
   uint32_t field = length_field();
   if ((field & kHashComputedMask) && !(field & kIsArrayIndexMask)) return false;
   return SlowAsArrayIndex(index);
 }
 
@@ skipping 105 matching lines @@
 #undef WRITE_INT_FIELD
 #undef READ_SHORT_FIELD
 #undef WRITE_SHORT_FIELD
 #undef READ_BYTE_FIELD
 #undef WRITE_BYTE_FIELD
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_INL_H_