Couple the enumeration index of a property to the size of the descriptor array where it first appea…

src/objects-inl.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 2077 matching lines @@
              GetValue(descriptor_number),
              GetDetails(descriptor_number));
 }
 
 
 void DescriptorArray::Set(int descriptor_number,
                           Descriptor* desc,
                           const WhitenessWitness&) {
   // Range check.
   ASSERT(descriptor_number < number_of_descriptors());
+  ASSERT(desc->GetDetails().index() <= number_of_descriptors());
   ASSERT(desc->GetDetails().index() > 0);
 
   NoIncrementalWriteBarrierSet(this,
                                ToKeyIndex(descriptor_number),
                                desc->GetKey());
   NoIncrementalWriteBarrierSet(this,
                                ToValueIndex(descriptor_number),
                                desc->GetValue());
   NoIncrementalWriteBarrierSet(this,
                                ToDetailsIndex(descriptor_number),
                                desc->GetDetails().AsSmi());
 }
 
 
+void DescriptorArray::Append(int descriptor_number,
+                             Descriptor* desc,
+                             const WhitenessWitness& witness) {
+  desc->SetEnumerationIndex(descriptor_number + 1);
+  Set(descriptor_number, desc, witness);
+}
+
+
 void DescriptorArray::NoIncrementalWriteBarrierSwapDescriptors(
     int first, int second) {
   NoIncrementalWriteBarrierSwap(this, ToKeyIndex(first), ToKeyIndex(second));
   NoIncrementalWriteBarrierSwap(this,
                                 ToValueIndex(first),
                                 ToValueIndex(second));
   NoIncrementalWriteBarrierSwap(this,
                                 ToDetailsIndex(first),
                                 ToDetailsIndex(second));
 }
@@ skipping 3184 matching lines @@
 #undef WRITE_UINT32_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_