Simplify CheckPrototypeMaps.

src/hydrogen.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 3777 matching lines @@
                                              Handle<Map> receiver_map,
                                              bool smi_and_map_check) {
   // Constant functions have the nice property that the map will change if they
   // are overwritten.  Therefore it is enough to check the map of the holder and
   // its prototypes.
   if (smi_and_map_check) {
     AddInstruction(new HCheckNonSmi(receiver));
     AddInstruction(new HCheckMap(receiver, receiver_map));
   }
   if (!expr->holder().is_null()) {
-    AddInstruction(new HCheckPrototypeMaps(receiver,
-                                           expr->holder(),
-                                           receiver_map));
+    AddInstruction(new HCheckPrototypeMaps(
+        Handle<JSObject>(JSObject::cast(receiver_map->prototype())),
+        expr->holder()));
   }
 }
 
 
 void HGraphBuilder::HandlePolymorphicCallNamed(Call* expr,
                                                HValue* receiver,
                                                ZoneMapList* types,
                                                Handle<String> name) {
   int argument_count = expr->arguments()->length() + 1;  // Plus receiver.
   int number_of_types = Min(types->length(), kMaxCallPolymorphism);
@@ skipping 1975 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal