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

src/objects.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 5783 matching lines @@
   FixedArray* result;
   if (number_of_descriptors == 0 && shared_mode == MAY_BE_SHARED) {
     return heap->empty_descriptor_array();
   }
   // Allocate the array of keys.
   { MaybeObject* maybe_array =
         heap->AllocateFixedArray(ToKeyIndex(number_of_descriptors));
     if (!maybe_array->To(&result)) return maybe_array;
   }
 
-  result->set(kLastAddedIndex, Smi::FromInt(-1));
+  result->set(kLastAddedIndex, Smi::FromInt(kNoneAdded));
   result->set(kTransitionsIndex, Smi::FromInt(0));
   return result;
 }
 
 
 void DescriptorArray::SetEnumCache(FixedArray* bridge_storage,
                                    FixedArray* new_cache,
                                    Object* new_index_cache) {
   ASSERT(bridge_storage->length() >= kEnumCacheBridgeLength);
   ASSERT(new_index_cache->IsSmi() || new_index_cache->IsFixedArray());
@@ skipping 106 matching lines @@
 
   int new_size = number_of_descriptors() + 1;
 
   DescriptorArray* new_descriptors;
   { MaybeObject* maybe_result = Allocate(new_size, MAY_BE_SHARED);
     if (!maybe_result->To(&new_descriptors)) return maybe_result;
   }
 
   FixedArray::WhitenessWitness witness(new_descriptors);
 
-  descriptor->SetEnumerationIndex(NextEnumerationIndex());
+  ASSERT(new_size == NextEnumerationIndex());
+  descriptor->SetEnumerationIndex(new_size);
 
   // Copy the descriptors, inserting or replacing a descriptor.
   int insertion_index = -1;
   int to = 0;
   for (int from = 0; from < number_of_descriptors(); ++from) {
     if (insertion_index < 0 && InsertionPointFound(GetKey(from), key)) {
       insertion_index = to++;
     }
     MaybeObject* copy_result =
         new_descriptors->CopyFrom(to++, this, from, witness);
@@ skipping 86 matching lines @@
           child_index++;
           child_hash = right_child_hash;
         }
       }
       if (child_hash <= parent_hash) break;
       NoIncrementalWriteBarrierSwapDescriptors(parent_index, child_index);
       parent_index = child_index;
     }
   }
 
-  int last_enum_index = -1;
-  int last_added = -1;
+  ASSERT(LastAdded() == kNoneAdded);
   for (int i = 0; i < len; ++i) {
     int current_enum = GetDetails(i).index();
-    if (current_enum > last_enum_index) {
-      last_added = i;
-      last_enum_index = current_enum;
+    ASSERT(current_enum <= len);
+
+    if (current_enum == len) {
+      ASSERT(LastAdded() == kNoneAdded);
+      SetLastAdded(i);
+#ifndef DEBUG
+      return;
+#endif
     }
   }
-  SetLastAdded(last_added);
-
-  ASSERT(LastAdded() != -1);
+  ASSERT(LastAdded() != kNoneAdded);
 }
 
 
 void DescriptorArray::Sort(const WhitenessWitness& witness) {
   SortUnchecked(witness);
   SLOW_ASSERT(IsSortedNoDuplicates());
 }
 
 
 MaybeObject* AccessorPair::CopyWithoutTransitions() {
@@ skipping 7238 matching lines @@
   set_year(Smi::FromInt(year), SKIP_WRITE_BARRIER);
   set_month(Smi::FromInt(month), SKIP_WRITE_BARRIER);
   set_day(Smi::FromInt(day), SKIP_WRITE_BARRIER);
   set_weekday(Smi::FromInt(weekday), SKIP_WRITE_BARRIER);
   set_hour(Smi::FromInt(hour), SKIP_WRITE_BARRIER);
   set_min(Smi::FromInt(min), SKIP_WRITE_BARRIER);
   set_sec(Smi::FromInt(sec), SKIP_WRITE_BARRIER);
 }
 
 } }  // namespace v8::internal