Migrate instance of deprecated maps in HCheckMaps.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 5a113f7c9c652e2fab1370bd3bc80faa283a5af4..80a932656a4d6410369960908cb1210fb56239d8 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4961,31 +4961,64 @@ void LCodeGen::DoCheckFunction(LCheckFunction* instr) {
 }
 
 
-void LCodeGen::DoCheckMapCommon(Register reg,
-                                Handle<Map> map,
-                                LInstruction* instr) {
-  Label success;
-  __ CompareMap(reg, map, &success);
-  DeoptimizeIf(not_equal, instr->environment());
-  __ bind(&success);
+void LCodeGen::DoDeferredInstanceMigration(LCheckMaps* instr, Register object) {
+  {
+    PushSafepointRegistersScope scope(this);
+    __ push(object);
+    CallRuntimeFromDeferred(Runtime::kMigrateInstance, 1, instr);
+    __ testq(rax, Immediate(kSmiTagMask));
+  }
+  DeoptimizeIf(zero, instr->environment());
 }
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
+  class DeferredCheckMaps: public LDeferredCode {
+   public:
+    DeferredCheckMaps(LCodeGen* codegen, LCheckMaps* instr, Register object)
+        : LDeferredCode(codegen), instr_(instr), object_(object) {
+      SetExit(check_maps());
+    }
+    virtual void Generate() {
+      codegen()->DoDeferredInstanceMigration(instr_, object_);
+    }
+    Label* check_maps() { return &check_maps_; }
+    virtual LInstruction* instr() { return instr_; }
+   private:
+    LCheckMaps* instr_;
+    Label check_maps_;
+    Register object_;
+  };
+
   if (instr->hydrogen()->CanOmitMapChecks()) return;
+
   LOperand* input = instr->value();
   ASSERT(input->IsRegister());
   Register reg = ToRegister(input);
 
-  Label success;
   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());
+  }
+
+  Label success;
   for (int i = 0; i < map_set->length() - 1; i++) {
     Handle<Map> map = map_set->at(i);
     __ CompareMap(reg, map, &success);
     __ j(equal, &success);
   }
+
   Handle<Map> map = map_set->last();
-  DoCheckMapCommon(reg, map, instr);
+  __ CompareMap(reg, map, &success);
+  if (instr->hydrogen()->has_migration_target()) {
+    __ j(not_equal, deferred->entry());
+  } else {
+    DeoptimizeIf(not_equal, instr->environment());
+  }
+
   __ bind(&success);
 }