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

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/js-type-feedback.h"
@@ skipping 1998 matching lines @@
     environment()->Push(result);
   }
 
   ast_context()->ProduceValue(environment()->Pop());
 }
 
 
 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();
   LhsKind assign_type = Property::GetAssignType(property);
 
   // Evaluate LHS expression and store the value.
   switch (assign_type) {
     case VARIABLE: {
       Variable* var = expr->AsVariableProxy()->var();
       FrameStateBeforeAndAfter states(this, BailoutId::None());
@@ skipping 53 matching lines @@
       Node* store = BuildKeyedSuperStore(receiver, home_object, key, value,
                                          TypeFeedbackId::None());
       states.AddToNode(store, bailout_id, OutputFrameStateCombine::Ignore());
       break;
     }
   }
 }
 
 
 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();
   LhsKind assign_type = Property::GetAssignType(property);
   bool needs_frame_state_before = true;
 
   // Evaluate LHS expression.
   switch (assign_type) {
     case VARIABLE: {
       Variable* variable = expr->target()->AsVariableProxy()->var();
@@ skipping 409 matching lines @@
   ZoneList<Expression*>* args = expr->arguments();
   VisitForValues(args);
 
   // Original constructor is loaded from the {new.target} variable.
   VisitForValue(super->new_target_var());
 
   // Create node to perform the super call.
   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);
 }
 
 
 void AstGraphBuilder::VisitCallNew(CallNew* expr) {
   VisitForValue(expr->expression());
 
   // Evaluate all arguments to the construct call.
   ZoneList<Expression*>* args = expr->arguments();
   VisitForValues(args);
@@ skipping 81 matching lines @@
       return VisitTypeof(expr);
     case Token::NOT:
       return VisitNot(expr);
     default:
       UNREACHABLE();
   }
 }
 
 
 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();
   LhsKind assign_type = Property::GetAssignType(property);
 
   // Reserve space for result of postfix operation.
   bool is_postfix = expr->is_postfix() && !ast_context()->IsEffect();
   if (is_postfix) environment()->Push(jsgraph()->UndefinedConstant());
 
   // Evaluate LHS expression and get old value.
@@ skipping 1679 matching lines @@
     // Phi does not exist yet, introduce one.
     value = NewPhi(inputs, value, control);
     value->ReplaceInput(inputs - 1, other);
   }
   return value;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8