[builtins] Remove the ObjectConstructor_ConstructStub builtin.

This is the first step on the way to eventually get rid of the
construct_stub field in SharedFunctionInfos.

Bug: v8:7503
Change-Id: Ib14627613851c7f2a5ab795c642bb74176285863
Reviewed-on: https://chromium-review.googlesource.com/940222Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51625}

src/bootstrapper.cc

@@ -762,7 +762,7 @@ void Genesis::CreateObjectFunction(Handle<JSFunction> empty_function) {
   object_fun->shared()->set_length(1);
   object_fun->shared()->DontAdaptArguments();
   object_fun->shared()->SetConstructStub(
-      *BUILTIN_CODE(isolate_, ObjectConstructor_ConstructStub));
+      *BUILTIN_CODE(isolate_, JSBuiltinsConstructStub));
   native_context()->set_object_function(*object_fun);
 
   {

src/builtins/builtins-constructor-gen.cc

@@ -636,49 +636,58 @@ Node* ConstructorBuiltinsAssembler::EmitCreateEmptyObjectLiteral(
   return result;
 }
 
+// ES #sec-object-constructor
 TF_BUILTIN(ObjectConstructor, ConstructorBuiltinsAssembler) {
   int const kValueArg = 0;
   Node* argc =
       ChangeInt32ToIntPtr(Parameter(BuiltinDescriptor::kArgumentsCount));
   CodeStubArguments args(this, argc);
-  Node* value = args.GetOptionalArgumentValue(kValueArg);
   Node* context = Parameter(BuiltinDescriptor::kContext);
+  Node* new_target = Parameter(BuiltinDescriptor::kNewTarget);
 
-  CSA_ASSERT(this, IsUndefined(Parameter(BuiltinDescriptor::kNewTarget)));
-
-  Label return_to_object(this);
-
-  GotoIf(Word32And(IsNotUndefined(value), IsNotNull(value)), &return_to_object);
-
-  args.PopAndReturn(EmitCreateEmptyObjectLiteral(context));
-
-  BIND(&return_to_object);
-  args.PopAndReturn(ToObject(context, value));
-}
-
-TF_BUILTIN(ObjectConstructor_ConstructStub, ConstructorBuiltinsAssembler) {
-  int const kValueArg = 0;
-  Node* argc =
-      ChangeInt32ToIntPtr(Parameter(BuiltinDescriptor::kArgumentsCount));
-  CodeStubArguments args(this, argc);
-  Node* value = args.GetOptionalArgumentValue(kValueArg);
-
+  VARIABLE(var_result, MachineRepresentation::kTagged);
+  Label if_subclass(this, Label::kDeferred), if_notsubclass(this),
+      return_result(this);
+  GotoIf(IsUndefined(new_target), &if_notsubclass);
   Node* target = LoadFromFrame(StandardFrameConstants::kFunctionOffset,
                                MachineType::TaggedPointer());
-  Node* new_target = Parameter(BuiltinDescriptor::kNewTarget);
-  Node* context = Parameter(BuiltinDescriptor::kContext);
+  Branch(WordEqual(new_target, target), &if_notsubclass, &if_subclass);
 
-  CSA_ASSERT(this, IsNotUndefined(new_target));
+  BIND(&if_subclass);
+  {
+    Node* result =
+        CallBuiltin(Builtins::kFastNewObject, context, target, new_target);
+    var_result.Bind(result);
+    Goto(&return_result);
+  }
+
+  BIND(&if_notsubclass);
+  {
+    Label if_newobject(this, Label::kDeferred), if_toobject(this);
 
-  Label return_to_object(this);
+    Node* value_index = IntPtrConstant(kValueArg);
+    GotoIf(UintPtrGreaterThanOrEqual(value_index, argc), &if_newobject);
+    Node* value = args.AtIndex(value_index);
+    GotoIf(IsNull(value), &if_newobject);
+    Branch(IsUndefined(value), &if_newobject, &if_toobject);
 
-  GotoIf(Word32And(WordEqual(target, new_target),
-                   Word32And(IsNotUndefined(value), IsNotNull(value))),
-         &return_to_object);
-  args.PopAndReturn(EmitFastNewObject(context, target, new_target));
+    BIND(&if_newobject);
+    {
+      Node* result = EmitCreateEmptyObjectLiteral(context);
+      var_result.Bind(result);
+      Goto(&return_result);
+    }
+
+    BIND(&if_toobject);
+    {
+      Node* result = CallBuiltin(Builtins::kToObject, context, value);
+      var_result.Bind(result);
+      Goto(&return_result);
+    }
+  }
 
-  BIND(&return_to_object);
-  args.PopAndReturn(ToObject(context, value));
+  BIND(&return_result);
+  args.PopAndReturn(var_result.value());
 }
 
 TF_BUILTIN(NumberConstructor, ConstructorBuiltinsAssembler) {

src/builtins/builtins-definitions.h

@@ -748,9 +748,8 @@ namespace internal {
   TFS(Negate, kValue)                                                          \
                                                                                \
   /* Object */                                                                 \
+  /* ES #sec-object-constructor */                                             \
   TFJ(ObjectConstructor, SharedFunctionInfo::kDontAdaptArgumentsSentinel)      \
-  TFJ(ObjectConstructor_ConstructStub,                                         \
-      SharedFunctionInfo::kDontAdaptArgumentsSentinel)                         \
   CPP(ObjectAssign)                                                            \
   /* ES #sec-object.create */                                                  \
   TFJ(ObjectCreate, SharedFunctionInfo::kDontAdaptArgumentsSentinel)           \

src/builtins/builtins.cc

@@ -262,7 +262,6 @@ bool Builtins::IsLazy(int index) {
     case kInterpreterEnterBytecodeAdvance:
     case kInterpreterEnterBytecodeDispatch:
     case kInterpreterEntryTrampoline:
-    case kObjectConstructor_ConstructStub:    // https://crbug.com/v8/6787.
     case kPromiseConstructorLazyDeoptContinuation:  // crbug/v8/6786.
     case kProxyConstructor_ConstructStub:     // https://crbug.com/v8/6787.
     case kNumberConstructor_ConstructStub:    // https://crbug.com/v8/6787.
@@ -659,7 +658,6 @@ bool Builtins::IsIsolateIndependent(int index) {
     case kNumberPrototypeValueOf:
     case kNumberToString:
     case kObjectConstructor:
-    case kObjectConstructor_ConstructStub:
     case kObjectCreate:
     case kObjectIs:
     case kObjectKeys: