Free up 11 bits in fast-mode PropertyDetails by removing the enumeration-index.

src/runtime.cc

 // 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 2298 matching lines @@
   if (function->HasFastProperties()) {
     // Construct a new field descriptor with updated attributes.
     DescriptorArray* instance_desc = function->map()->instance_descriptors();
 
     int index = instance_desc->SearchWithCache(name, function->map());
     ASSERT(index != DescriptorArray::kNotFound);
     PropertyDetails details = instance_desc->GetDetails(index);
 
     CallbacksDescriptor new_desc(name,
         instance_desc->GetValue(index),
-        static_cast<PropertyAttributes>(details.attributes() | READ_ONLY),
-        details.descriptor_index());
+        static_cast<PropertyAttributes>(details.attributes() | READ_ONLY));
 
     // Create a new map featuring the new field descriptors array.
     Map* new_map;
     MaybeObject* maybe_map =
         function->map()->CopyReplaceDescriptor(
             instance_desc, &new_desc, index, OMIT_TRANSITION);
     if (!maybe_map->To(&new_map)) return maybe_map;
 
     function->set_map(new_map);
   } else {  // Dictionary properties.
     // Directly manipulate the property details.
     int entry = function->property_dictionary()->FindEntry(name);
     ASSERT(entry != NameDictionary::kNotFound);
     PropertyDetails details = function->property_dictionary()->DetailsAt(entry);
     PropertyDetails new_details(
         static_cast<PropertyAttributes>(details.attributes() | READ_ONLY),
         details.type(),
-        Representation::None(),
         details.dictionary_index());
     function->property_dictionary()->DetailsAtPut(entry, new_details);
   }
   return function;
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, Runtime_FunctionIsAPIFunction) {
   NoHandleAllocation ha(isolate);
   ASSERT(args.length() == 1);
@@ skipping 11045 matching lines @@
     // Handle last resort GC and make sure to allow future allocations
     // to grow the heap without causing GCs (if possible).
     isolate->counters()->gc_last_resort_from_js()->Increment();
     isolate->heap()->CollectAllGarbage(Heap::kNoGCFlags,
                                        "Runtime::PerformGC");
   }
 }
 
 
 } }  // namespace v8::internal