Represent implicit 'this' binding by 'super' in AST.

This makes the implicit initializing assignment to 'this' performed
after a super constructor call explicit in the AST. It removes the
need to handle the special case where a CallExpression behaves like a
AssignmentExpression from various AstVisitor implementations.

R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/1226123010

Cr-Commit-Position: refs/heads/master@{#29705}

diff --git a/src/arm/full-codegen-arm.cc b/src/arm/full-codegen-arm.cc
index 4b74afd8993af58fe21ba979fd1047f749a72b85..421b7f33b005b38180502f57b4a29b6c4ffbc8b0 100644 (file)
--- a/src/arm/full-codegen-arm.cc
+++ b/src/arm/full-codegen-arm.cc
@@ -2000,7 +2000,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2677,7 +2677,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2825,6 +2825,20 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, r1);
+    __ ldr(r3, location);
+    __ CompareRoot(r3, Heap::kTheHoleValueRootIndex);
+    __ b(eq, &uninitialized_this);
+    __ mov(r0, Operand(var->name()));
+    __ Push(r0);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3176,22 +3190,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(r1, this_var);
-  __ CompareRoot(r1, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ b(eq, &uninitialized_this);
-  __ mov(r0, Operand(this_var->name()));
-  __ Push(r0);
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3413,7 +3411,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(r0);
 }
 
@@ -4744,9 +4741,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, r0);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4944,7 +4938,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/arm64/full-codegen-arm64.cc b/src/arm64/full-codegen-arm64.cc
index 825eed5be0bed5681f69fd4ab64e3ec0c7016d41..c95bbafecd67f338b48c7af81cc1307d45c71565 100644 (file)
--- a/src/arm64/full-codegen-arm64.cc
+++ b/src/arm64/full-codegen-arm64.cc
@@ -1977,7 +1977,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2359,7 +2359,7 @@ void FullCodeGenerator::EmitClassDefineProperties(ClassLiteral* lit,
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2508,6 +2508,19 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ Bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, x1);
+    __ Ldr(x10, location);
+    __ JumpIfRoot(x10, Heap::kTheHoleValueRootIndex, &uninitialized_this);
+    __ Mov(x0, Operand(var->name()));
+    __ Push(x0);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -2866,21 +2879,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(x1, this_var);
-  Label uninitialized_this;
-  __ JumpIfRoot(x1, Heap::kTheHoleValueRootIndex, &uninitialized_this);
-  __ Mov(x0, Operand(this_var->name()));
-  __ Push(x0);
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3103,7 +3101,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(x0);
 }
 
@@ -4434,9 +4431,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ Ldr(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, x0);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4632,7 +4626,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/ast.cc b/src/ast.cc
index 93cb6c09b99358f6a118f58e83442ef01f58e832..9dd825a6f96b96065806e9b8f489dd96364776a5 100644 (file)
--- a/src/ast.cc
+++ b/src/ast.cc
@@ -59,6 +59,12 @@ bool Expression::IsUndefinedLiteral(Isolate* isolate) const {
 }
 
 
+bool Expression::IsValidReferenceExpressionOrThis() const {
+  return IsValidReferenceExpression() ||
+         (IsVariableProxy() && AsVariableProxy()->is_this());
+}
+
+
 VariableProxy::VariableProxy(Zone* zone, Variable* var, int start_position,
                              int end_position)
     : Expression(zone, start_position),

diff --git a/src/ast.h b/src/ast.h
index b1a634edb4c7f02f4dc96658e3e9dba6c5cb9908..ee019e8f0fa60ee540fd9361029208bea07c27a8 100644 (file)
--- a/src/ast.h
+++ b/src/ast.h
@@ -339,6 +339,7 @@ class Expression : public AstNode {
     kTest
   };
 
+  // True iff the expression is a valid reference expression.
   virtual bool IsValidReferenceExpression() const { return false; }
 
   // Helpers for ToBoolean conversion.
@@ -362,6 +363,9 @@ class Expression : public AstNode {
   // True if we can prove that the expression is the undefined literal.
   bool IsUndefinedLiteral(Isolate* isolate) const;
 
+  // True iff the expression is a valid target for an assignment.
+  bool IsValidReferenceExpressionOrThis() const;
+
   // Expression type bounds
   Bounds bounds() const { return bounds_; }
   void set_bounds(Bounds bounds) { bounds_ = bounds; }

diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index 0c0bb02ea5bd24d1a5b83c207ff00652ca4608ce..c105f2c22c16f94e61f041d570f820d128539760 100644 (file)
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -2016,7 +2016,7 @@ void AstGraphBuilder::VisitArrayLiteral(ArrayLiteral* expr) {
 void AstGraphBuilder::VisitForInAssignment(Expression* expr, Node* value,
                                            const VectorSlotPair& feedback,
                                            BailoutId bailout_id) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->AsProperty();
@@ -2090,7 +2090,7 @@ void AstGraphBuilder::VisitForInAssignment(Expression* expr, Node* value,
 
 
 void AstGraphBuilder::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->target()->AsProperty();
@@ -2520,12 +2520,6 @@ void AstGraphBuilder::VisitCallSuper(Call* expr) {
   const Operator* call = javascript()->CallConstruct(args->length() + 2);
   Node* value = ProcessArguments(call, args->length() + 2);
   PrepareFrameState(value, expr->id(), ast_context()->GetStateCombine());
-
-  // TODO(mstarzinger): It sure would be nice if this were desugared.
-  FrameStateBeforeAndAfter states(this, BailoutId::None());
-  BuildVariableAssignment(super->this_var()->var(), value, Token::INIT_CONST,
-                          VectorSlotPair(), expr->id(), states);
-
   ast_context()->ProduceValue(value);
 }
 
@@ -2627,7 +2621,7 @@ void AstGraphBuilder::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void AstGraphBuilder::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   // Left-hand side can only be a property, a global or a variable slot.
   Property* property = expr->expression()->AsProperty();

diff --git a/src/compiler/ast-loop-assignment-analyzer.cc b/src/compiler/ast-loop-assignment-analyzer.cc
index e0a92a464c487e7e1b74b88321d28298c2502f33..61ed4f27cbba8e7d7b9287108a87ab9e8f3435e2 100644 (file)
--- a/src/compiler/ast-loop-assignment-analyzer.cc
+++ b/src/compiler/ast-loop-assignment-analyzer.cc
@@ -161,11 +161,6 @@ void ALAA::VisitProperty(Property* e) {
 void ALAA::VisitCall(Call* e) {
   Visit(e->expression());
   VisitExpressions(e->arguments());
-  // TODO(mstarzinger): It sure would be nice if this were desugared.
-  if (e->GetCallType(isolate()) == Call::SUPER_CALL) {
-    SuperCallReference* super = e->expression()->AsSuperCallReference();
-    AnalyzeAssignment(super->this_var()->var());
-  }
 }
 
 

diff --git a/src/full-codegen.h b/src/full-codegen.h
index ccc10e061bcdfd8704cbae57caee662ff19ca7e2..88a88f45b2d56c5924e0219bfc7d8ca29d7f5b52 100644 (file)
--- a/src/full-codegen.h
+++ b/src/full-codegen.h
@@ -644,9 +644,6 @@ class FullCodeGenerator: public AstVisitor {
       FeedbackVectorICSlot slot = FeedbackVectorICSlot::Invalid());
 
   void EmitLoadSuperConstructor(SuperCallReference* super_call_ref);
-  void EmitInitializeThisAfterSuper(
-      SuperCallReference* super_call_ref,
-      FeedbackVectorICSlot slot = FeedbackVectorICSlot::Invalid());
 
   void CallIC(Handle<Code> code,
               TypeFeedbackId id = TypeFeedbackId::None());

diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index a317977f39bbdf991068786ab9973746ebfdfdca..d2b0c10796c7e67880ac3c47b60071154446a20d 100644 (file)
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -1927,7 +1927,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2584,7 +2584,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2726,6 +2726,19 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, ecx);
+    __ mov(edx, location);
+    __ cmp(edx, isolate()->factory()->the_hole_value());
+    __ j(equal, &uninitialized_this);
+    __ push(Immediate(var->name()));
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3068,22 +3081,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_call_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_call_ref->this_var()->var();
-  GetVar(ecx, this_var);
-  __ cmp(ecx, isolate()->factory()->the_hole_value());
-
-  Label uninitialized_this;
-  __ j(equal, &uninitialized_this);
-  __ push(Immediate(this_var->name()));
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3299,7 +3296,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(eax);
 }
 
@@ -4675,9 +4671,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, eax);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4876,7 +4869,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 71acc700c36f2113ac2b0eb0609b00fdc43709f2..9b36719e324543560668e42339c9b2afbe1754af 100644 (file)
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -1993,7 +1993,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2662,7 +2662,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2811,6 +2811,20 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, a1);
+    __ lw(a3, location);
+    __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
+    __ Branch(&uninitialized_this, eq, a3, Operand(at));
+    __ li(a0, Operand(var->name()));
+    __ Push(a0);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3160,22 +3174,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(a1, this_var);
-  __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ Branch(&uninitialized_this, eq, a1, Operand(at));
-  __ li(a0, Operand(this_var->name()));
-  __ Push(a0);
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3395,7 +3393,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(v0);
 }
 
@@ -4761,9 +4758,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, v0);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4961,7 +4955,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/mips64/full-codegen-mips64.cc b/src/mips64/full-codegen-mips64.cc
index ebd9abe813f664a6142dba9ba9fb57fe5951be25..1102b9e28c98fa9936b6f7b0389d0810a5e5f1b1 100644 (file)
--- a/src/mips64/full-codegen-mips64.cc
+++ b/src/mips64/full-codegen-mips64.cc
@@ -1989,7 +1989,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2659,7 +2659,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2808,6 +2808,20 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, a1);
+    __ ld(a3, location);
+    __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
+    __ Branch(&uninitialized_this, eq, a3, Operand(at));
+    __ li(a0, Operand(var->name()));
+    __ Push(a0);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3160,22 +3174,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(a1, this_var);
-  __ LoadRoot(at, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ Branch(&uninitialized_this, eq, a1, Operand(at));
-  __ li(a0, Operand(this_var->name()));
-  __ Push(a0);
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3395,7 +3393,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(v0);
 }
 
@@ -4763,9 +4760,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ ld(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, v0);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4962,7 +4956,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/ppc/full-codegen-ppc.cc b/src/ppc/full-codegen-ppc.cc
index fcf21d358ceff40b5eccf96482ce6bd99b04952c..ddb100c1971ba3f7676b2d8ba7ce16b97c054aaf 100644 (file)
--- a/src/ppc/full-codegen-ppc.cc
+++ b/src/ppc/full-codegen-ppc.cc
@@ -1959,7 +1959,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2676,7 +2676,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2824,6 +2824,20 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, r4);
+    __ LoadP(r6, location);
+    __ CompareRoot(r6, Heap::kTheHoleValueRootIndex);
+    __ beq(&uninitialized_this);
+    __ mov(r4, Operand(var->name()));
+    __ push(r4);
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3166,22 +3180,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(r4, this_var);
-  __ CompareRoot(r4, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ beq(&uninitialized_this);
-  __ mov(r4, Operand(this_var->name()));
-  __ push(r4);
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3403,7 +3401,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(r3);
 }
 
@@ -4763,9 +4760,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ LoadP(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, r3);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4959,7 +4953,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/preparser.h b/src/preparser.h
index 921cd875a1816abaee53eed6db15e6222465bc5a..8680f88bf940ff208f9b419ca90d048e98917374 100644 (file)
--- a/src/preparser.h
+++ b/src/preparser.h
@@ -947,10 +947,16 @@ class PreParserExpression {
                                ExpressionTypeField::encode(kCallExpression));
   }
 
+  static PreParserExpression SuperCallReference() {
+    return PreParserExpression(
+        TypeField::encode(kExpression) |
+        ExpressionTypeField::encode(kSuperCallReference));
+  }
+
   static PreParserExpression NoTemplateTag() {
-    return PreParserExpression(TypeField::encode(kExpression) |
-                               ExpressionTypeField::encode(
-                                  kNoTemplateTagExpression));
+    return PreParserExpression(
+        TypeField::encode(kExpression) |
+        ExpressionTypeField::encode(kNoTemplateTagExpression));
   }
 
   bool IsIdentifier() const {
@@ -997,6 +1003,11 @@ class PreParserExpression {
            ExpressionTypeField::decode(code_) == kCallExpression;
   }
 
+  bool IsSuperCallReference() const {
+    return TypeField::decode(code_) == kExpression &&
+           ExpressionTypeField::decode(code_) == kSuperCallReference;
+  }
+
   bool IsValidReferenceExpression() const {
     return IsIdentifier() || IsProperty();
   }
@@ -1045,6 +1056,7 @@ class PreParserExpression {
     kThisPropertyExpression,
     kPropertyExpression,
     kCallExpression,
+    kSuperCallReference,
     kNoTemplateTagExpression
   };
 
@@ -1528,7 +1540,7 @@ class PreParserTraits {
   static PreParserExpression SuperCallReference(Scope* scope,
                                                 PreParserFactory* factory,
                                                 int pos) {
-    return PreParserExpression::Default();
+    return PreParserExpression::SuperCallReference();
   }
 
   static PreParserExpression NewTargetExpression(Scope* scope,
@@ -3184,12 +3196,22 @@ ParserBase<Traits>::ParseLeftHandSideExpression(
         // they are actually direct calls to eval is determined at run time.
         this->CheckPossibleEvalCall(result, scope_);
 
+        bool is_super_call = result->IsSuperCallReference();
         if (spread_pos.IsValid()) {
           args = Traits::PrepareSpreadArguments(args);
           result = Traits::SpreadCall(result, args, pos);
         } else {
           result = factory()->NewCall(result, args, pos);
         }
+
+        // Explicit calls to the super constructor using super() perform an
+        // implicit binding assignment to the 'this' variable.
+        if (is_super_call) {
+          ExpressionT this_expr = this->ThisExpression(scope_, factory(), pos);
+          result = factory()->NewAssignment(Token::INIT_CONST, this_expr,
+                                            result, pos);
+        }
+
         if (fni_ != NULL) fni_->RemoveLastFunction();
         break;
       }
@@ -3462,10 +3484,15 @@ ParserBase<Traits>::ParseStrongSuperCallExpression(
   function_state_->set_super_location(super_loc);
   if (spread_pos.IsValid()) {
     args = Traits::PrepareSpreadArguments(args);
-    return Traits::SpreadCall(expr, args, pos);
+    expr = Traits::SpreadCall(expr, args, pos);
   } else {
-    return factory()->NewCall(expr, args, pos);
+    expr = factory()->NewCall(expr, args, pos);
   }
+
+  // Explicit calls to the super constructor using super() perform an implicit
+  // binding assignment to the 'this' variable.
+  ExpressionT this_expr = this->ThisExpression(scope_, factory(), pos);
+  return factory()->NewAssignment(Token::INIT_CONST, this_expr, expr, pos);
 }
 
 

diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 8f2da733f016b1872251eff8d6a64ec61d489cdf..a84a8e6d9c6675f511324edccb91d8bcc3c223b3 100644 (file)
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -1952,7 +1952,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2578,7 +2578,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2720,6 +2720,19 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, rcx);
+    __ movp(rdx, location);
+    __ CompareRoot(rdx, Heap::kTheHoleValueRootIndex);
+    __ j(equal, &uninitialized_this);
+    __ Push(var->name());
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3061,21 +3074,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_ref->this_var()->var();
-  GetVar(rcx, this_var);
-  __ CompareRoot(rcx, Heap::kTheHoleValueRootIndex);
-  Label uninitialized_this;
-  __ j(equal, &uninitialized_this);
-  __ Push(this_var->name());
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3290,7 +3288,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(rax);
 }
 
@@ -4692,9 +4689,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, rax);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4894,7 +4888,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/src/x87/full-codegen-x87.cc b/src/x87/full-codegen-x87.cc
index d5b53af324fab3014e7acf8b6d682e550514ae21..8b84d9404fb8875264862f64e98f2714c77ea152 100644 (file)
--- a/src/x87/full-codegen-x87.cc
+++ b/src/x87/full-codegen-x87.cc
@@ -1918,7 +1918,7 @@ void FullCodeGenerator::VisitArrayLiteral(ArrayLiteral* expr) {
 
 
 void FullCodeGenerator::VisitAssignment(Assignment* expr) {
-  DCHECK(expr->target()->IsValidReferenceExpression());
+  DCHECK(expr->target()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ Assignment");
   SetExpressionPosition(expr, INSERT_BREAK);
@@ -2575,7 +2575,7 @@ void FullCodeGenerator::EmitBinaryOp(BinaryOperation* expr, Token::Value op) {
 
 void FullCodeGenerator::EmitAssignment(Expression* expr,
                                        FeedbackVectorICSlot slot) {
-  DCHECK(expr->IsValidReferenceExpression());
+  DCHECK(expr->IsValidReferenceExpressionOrThis());
 
   Property* prop = expr->AsProperty();
   LhsKind assign_type = Property::GetAssignType(prop);
@@ -2717,6 +2717,19 @@ void FullCodeGenerator::EmitVariableAssignment(Variable* var, Token::Value op,
     __ bind(&const_error);
     __ CallRuntime(Runtime::kThrowConstAssignError, 0);
 
+  } else if (var->is_this() && op == Token::INIT_CONST) {
+    // Initializing assignment to const {this} needs a write barrier.
+    DCHECK(var->IsStackAllocated() || var->IsContextSlot());
+    Label uninitialized_this;
+    MemOperand location = VarOperand(var, ecx);
+    __ mov(edx, location);
+    __ cmp(edx, isolate()->factory()->the_hole_value());
+    __ j(equal, &uninitialized_this);
+    __ push(Immediate(var->name()));
+    __ CallRuntime(Runtime::kThrowReferenceError, 1);
+    __ bind(&uninitialized_this);
+    EmitStoreToStackLocalOrContextSlot(var, location);
+
   } else if (!var->is_const_mode() || op == Token::INIT_CONST) {
     if (var->IsLookupSlot()) {
       // Assignment to var.
@@ -3059,22 +3072,6 @@ void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
 }
 
 
-void FullCodeGenerator::EmitInitializeThisAfterSuper(
-    SuperCallReference* super_call_ref, FeedbackVectorICSlot slot) {
-  Variable* this_var = super_call_ref->this_var()->var();
-  GetVar(ecx, this_var);
-  __ cmp(ecx, isolate()->factory()->the_hole_value());
-
-  Label uninitialized_this;
-  __ j(equal, &uninitialized_this);
-  __ push(Immediate(this_var->name()));
-  __ CallRuntime(Runtime::kThrowReferenceError, 1);
-  __ bind(&uninitialized_this);
-
-  EmitVariableAssignment(this_var, Token::INIT_CONST, slot);
-}
-
-
 // See http://www.ecma-international.org/ecma-262/6.0/#sec-function-calls.
 void FullCodeGenerator::PushCalleeAndWithBaseObject(Call* expr) {
   VariableProxy* callee = expr->expression()->AsVariableProxy();
@@ -3290,7 +3287,6 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   RecordJSReturnSite(expr);
 
-  EmitInitializeThisAfterSuper(super_call_ref, expr->CallFeedbackICSlot());
   context()->Plug(eax);
 }
 
@@ -4665,9 +4661,6 @@ void FullCodeGenerator::EmitCallSuperWithSpread(CallRuntime* expr) {
   // Restore context register.
   __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
   context()->DropAndPlug(1, eax);
-
-  // TODO(mvstanton): with FLAG_vector_stores this needs a slot id.
-  EmitInitializeThisAfterSuper(super_call_ref);
 }
 
 
@@ -4866,7 +4859,7 @@ void FullCodeGenerator::VisitUnaryOperation(UnaryOperation* expr) {
 
 
 void FullCodeGenerator::VisitCountOperation(CountOperation* expr) {
-  DCHECK(expr->expression()->IsValidReferenceExpression());
+  DCHECK(expr->expression()->IsValidReferenceExpressionOrThis());
 
   Comment cmnt(masm_, "[ CountOperation");
 

diff --git a/test/mjsunit/harmony/super.js b/test/mjsunit/harmony/super.js
index 270c159e80b22a1c9b1389e76d8d1262068205c2..ab572b056f262e39dcf522d090cc9667c19309dd 100644 (file)
--- a/test/mjsunit/harmony/super.js
+++ b/test/mjsunit/harmony/super.js
@@ -1979,7 +1979,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
 
   class Derived extends Base {
     constructor() {
-      super();
+      let r = super();
+      assertEquals(this, r);
       derivedCalled++;
     }
   }
@@ -1995,7 +1996,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
 
   class DerivedDerived extends Derived {
     constructor() {
-      super();
+      let r = super();
+      assertEquals(this, r);
       derivedDerivedCalled++;
     }
   }
@@ -2015,7 +2017,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
   }
   class Derived2 extends Base2 {
     constructor(v1, v2) {
-      super(v1);
+      let r = super(v1);
+      assertEquals(this, r);
       this.fromDerived = v2;
     }
   }
@@ -2128,7 +2131,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
   }
   class Derived extends Base {
     constructor(x) {
-      eval('super(x)');
+      let r = eval('super(x)');
+      assertEquals(this, r);
     }
   }
   let d = new Derived(42);
@@ -2145,7 +2149,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
   }
   class Derived extends Base {
     constructor(x) {
-      (() => super(x))();
+      let r = (() => super(x))();
+      assertEquals(this, r);
     }
   }
   let d = new Derived(42);
@@ -2231,7 +2236,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
   }
   class Derived extends Base {
     constructor(x) {
-      eval('super(...[x])');
+      let r = eval('super(...[x])');
+      assertEquals(this, r);
     }
   }
   let d = new Derived(42);
@@ -2248,7 +2254,8 @@ TestKeyedSetterCreatingOwnPropertiesNonConfigurable(42, 43, 44);
   }
   class Derived extends Base {
     constructor(x) {
-      (() => super(...[x]))();
+      let r = (() => super(...[x]))();
+      assertEquals(this, r);
     }
   }
   let d = new Derived(42);