Migrate instance of deprecated maps in HCheckMaps.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index ddba1e19c3558e6cda7825ece911c189e214b526..8d91f0754346253a14ca8a1ab022e1ed5085e40c 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -882,7 +882,7 @@ void LCodeGen::LoadContextFromDeferred(LOperand* context) {
   } else if (context->IsConstantOperand()) {
     HConstant* constant =
         chunk_->LookupConstant(LConstantOperand::cast(context));
-    __ LoadHeapObject(esi, Handle<Context>::cast(constant->handle()));
+    __ LoadObject(esi, Handle<Object>::cast(constant->handle()));
   } else {
     UNREACHABLE();
   }
@@ -5793,31 +5793,67 @@ 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, instr->context());

[danno, 2013/08/05 14:36:59]

I think you can make the code much smaller and simplify things even more if you
don't use CallRuntimeFromDeferred here at all. Perhaps just a new version called
CallRuntimeFromDeferredNoContext that just does:

__ xor (esi, esi)
__ CallRuntimeSaveDoubles(id);
__ RecordSafepointWithRegisters(instr->pointer_map(), argc,
Safepoint::kNoLazyDeopt);

[Toon Verwaest, 2013/08/05 15:03:26]

Done.

+    __ test(eax, Immediate(kSmiTagMask));
+  }
+  DeoptimizeIf(zero, instr->environment());
 }
 
 
 void LCodeGen::DoCheckMaps(LCheckMaps* instr) {
+  class DeferredInstanceMigration: public LDeferredCode {
+   public:
+    DeferredInstanceMigration(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();
+
+  DeferredInstanceMigration* deferred = NULL;
+  if (instr->hydrogen()->has_migration_target()) {
+    deferred = new(zone()) DeferredInstanceMigration(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);
 }