Use UniqueSet<T> and Unique<T> in HCheckMaps and HCheckValue.

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 4852 matching lines @@
       __ andb(kScratchRegister, Immediate(mask));
       __ cmpb(kScratchRegister, Immediate(tag));
       DeoptimizeIf(not_equal, instr->environment());
     }
   }
 }
 
 
 void LCodeGen::DoCheckValue(LCheckValue* instr) {
   Register reg = ToRegister(instr->value());
-  Handle<HeapObject> object = instr->hydrogen()->object();
+  Handle<HeapObject> object = instr->hydrogen()->object().handle();
   __ CmpHeapObject(reg, object);
   DeoptimizeIf(not_equal, instr->environment());
 }
 
 
 void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
   {
     PushSafepointRegistersScope scope(this);
     __ push(object);
     CallRuntimeFromDeferred(Runtime::kMigrateInstance, 1, instr);
@@ skipping 20 matching lines @@
     Label check_maps_;
     Register object_;
   };
 
   if (instr->hydrogen()->CanOmitMapChecks()) return;
 
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
-  SmallMapList* map_set = instr->hydrogen()->map_set();
-
   DeferredCheckMaps* deferred = NULL;
   if (instr->hydrogen()->has_migration_target()) {
     deferred = new(zone()) DeferredCheckMaps(this, instr, reg);
     __ bind(deferred->check_maps());
   }
 
+  UniqueSet<Map> map_set = instr->hydrogen()->map_set();
   Label success;
-  for (int i = 0; i < map_set->length() - 1; i++) {
-    Handle<Map> map = map_set->at(i);
+  for (int i = 0; i < map_set.size() - 1; i++) {
+    Handle<Map> map = map_set.at(i).handle();
     __ CompareMap(reg, map, &success);
     __ j(equal, &success);
   }
 
-  Handle<Map> map = map_set->last();
+  Handle<Map> map = map_set.at(map_set.size() - 1).handle();
   __ CompareMap(reg, map, &success);
   if (instr->hydrogen()->has_migration_target()) {
     __ j(not_equal, deferred->entry());
   } else {
     DeoptimizeIf(not_equal, instr->environment());
   }
 
   __ bind(&success);
 }
 
@@ skipping 561 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64