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

src/arm64/full-codegen-arm64.cc

Index: src/arm64/full-codegen-arm64.cc
diff --git a/src/arm64/full-codegen-arm64.cc b/src/arm64/full-codegen-arm64.cc
index 9b31556c7783a407a9ece35f20038768c3b5266a..7e6043e1e8fc4170da0a7eda8b520b928054e20f 100644
--- 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");