Cache multiple ElementsKind map transition per map.

src/objects-printer.cc

 // Copyright 2011 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 297 matching lines @@
           break;
         }
         case CONSTANT_FUNCTION:
           descs->GetConstantFunction(i)->ShortPrint(out);
           PrintF(out, " (constant function)\n");
           break;
         case CALLBACKS:
           descs->GetCallbacksObject(i)->ShortPrint(out);
           PrintF(out, " (callback)\n");
           break;
-        case ELEMENTS_TRANSITION:
+        case ELEMENTS_TRANSITION: {
           PrintF(out, "(elements transition to ");
-          PrintElementsKind(out,
-                            Map::cast(descs->GetValue(i))->elements_kind());
+          Object* descriptor_contents = descs->GetValue(i);
+          if (descriptor_contents->IsMap()) {
+            Map* map = Map::cast(descriptor_contents);
+            PrintElementsKind(out, map->elements_kind());
+          } else {
+            FixedArray* map_array = FixedArray::cast(descriptor_contents);
+            for (int i = 0; i < map_array->length(); ++i) {
+              Map* map = Map::cast(map_array->get(i));
+              if (i != 0) {
+                PrintF(out, ", ");
+              }
+              PrintElementsKind(out, map->elements_kind());
+            }
+          }
           PrintF(out, ")\n");
           break;
+        }
         case MAP_TRANSITION:
           PrintF(out, "(map transition)\n");
           break;
         case CONSTANT_TRANSITION:
           PrintF(out, "(constant transition)\n");
           break;
         case NULL_DESCRIPTOR:
           PrintF(out, "(null descriptor)\n");
           break;
         default:
@@ skipping 650 matching lines @@
     desc.Print(out);
   }
   PrintF(out, "\n");
 }
 
 
 #endif  // OBJECT_PRINT
 
 
 } }  // namespace v8::internal