Promoting elements transitions to their own field.

src/property.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 43 matching lines @@
     case NORMAL:
       PrintF(out, " -type = normal\n");
       PrintF(out, " -entry = %d", GetDictionaryEntry());
       break;
     case MAP_TRANSITION:
       PrintF(out, " -type = map transition\n");
       PrintF(out, " -map:\n");
       GetTransitionMap()->Print(out);
       PrintF(out, "\n");
       break;
-    case ELEMENTS_TRANSITION:
-      PrintF(out, " -type = elements transition\n");
-      PrintF(out, " -map:\n");
-      GetTransitionMap()->Print(out);
-      PrintF(out, "\n");
-      break;
     case CONSTANT_FUNCTION:
       PrintF(out, " -type = constant function\n");
       PrintF(out, " -function:\n");
       GetConstantFunction()->Print(out);
       PrintF(out, "\n");
       break;
     case FIELD:
       PrintF(out, " -type = field\n");
       PrintF(out, " -index = %d", GetFieldIndex());
       PrintF(out, "\n");
@@ skipping 31 matching lines @@
 }
 
 
 #endif
 
 
 bool Descriptor::ContainsTransition() {
   switch (details_.type()) {
     case MAP_TRANSITION:
     case CONSTANT_TRANSITION:
-    case ELEMENTS_TRANSITION:
       return true;
     case CALLBACKS: {
       if (!value_->IsAccessorPair()) return false;
       AccessorPair* accessors = AccessorPair::cast(value_);
       return accessors->getter()->IsMap() || accessors->setter()->IsMap();
     }
     case NORMAL:
     case FIELD:
     case CONSTANT_FUNCTION:
     case HANDLER:
     case INTERCEPTOR:
     case NULL_DESCRIPTOR:
       return false;
   }
   UNREACHABLE();  // Keep the compiler happy.
   return false;
 }
 
 
 } }  // namespace v8::internal