[stubs] Unify (and optimize) implementation of ToObject.

src/full-codegen/x64/full-codegen-x64.cc

Index: src/full-codegen/x64/full-codegen-x64.cc
diff --git a/src/full-codegen/x64/full-codegen-x64.cc b/src/full-codegen/x64/full-codegen-x64.cc
index 6fe3062f2ebe72176d6a364ae061949449d39725..ca6bddb2015dfb717c6ad86baadf20380d0f02c7 100644
--- a/src/full-codegen/x64/full-codegen-x64.cc
+++ b/src/full-codegen/x64/full-codegen-x64.cc
@@ -1039,12 +1039,12 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
 
   // Convert the object to a JS object.
   Label convert, done_convert;
-  __ JumpIfSmi(rax, &convert);
+  __ JumpIfSmi(rax, &convert, Label::kNear);
   __ CmpObjectType(rax, FIRST_SPEC_OBJECT_TYPE, rcx);
-  __ j(above_equal, &done_convert);
+  __ j(above_equal, &done_convert, Label::kNear);
   __ bind(&convert);
-  __ Push(rax);
-  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
   __ bind(&done_convert);
   PrepareForBailoutForId(stmt->ToObjectId(), TOS_REG);
   __ Push(rax);
@@ -3912,6 +3912,19 @@ void FullCodeGenerator::EmitNumberToString(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitToObject(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  DCHECK_EQ(1, args->length());
+
+  // Load the argument into rax and convert it.
+  VisitForAccumulatorValue(args->at(0));
+
+  ToObjectStub stub(isolate());
+  __ CallStub(&stub);
+  context()->Plug(rax);
+}
+
+
 void FullCodeGenerator::EmitStringCharFromCode(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 1);