Make Variable::is_this always return the correct value

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/ast/scopes.h"
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
@@ skipping 2921 matching lines @@
   Visit(stmt->body());
 }
 
 
 void AstGraphBuilder::VisitDelete(UnaryOperation* expr) {
   Node* value;
   if (expr->expression()->IsVariableProxy()) {
     // Delete of an unqualified identifier is only allowed in classic mode but
     // deleting "this" is allowed in all language modes.
     Variable* variable = expr->expression()->AsVariableProxy()->var();
     // Delete of an unqualified identifier is disallowed in strict mode but

[Michael Starzinger, 2016/08/10 19:45:13]

nit: I know this is not your code, but while you are here, could you drop one of
those two comments that say the same thing twice. Thanks! :)

[Toon Verwaest, 2016/08/11 08:46:25]

Done.

     // "delete this" is allowed.
-    DCHECK(is_sloppy(language_mode()) || variable->HasThisName(isolate()));
+    DCHECK(is_sloppy(language_mode()) || variable->is_this());
     value = BuildVariableDelete(variable, expr->id(),
                                 ast_context()->GetStateCombine());
   } else if (expr->expression()->IsProperty()) {
     Property* property = expr->expression()->AsProperty();
     VisitForValue(property->obj());
     VisitForValue(property->key());
     Node* key = environment()->Pop();
     Node* object = environment()->Pop();
     value = NewNode(javascript()->DeleteProperty(language_mode()), object, key);
     PrepareFrameState(value, expr->id(), ast_context()->GetStateCombine());
@@ skipping 441 matching lines @@
       Node* name = jsgraph()->Constant(variable->name());
       const Operator* op = javascript()->DeleteProperty(language_mode());
       Node* result = NewNode(op, global, name);
       PrepareFrameState(result, bailout_id, combine);
       return result;
     }
     case VariableLocation::PARAMETER:
     case VariableLocation::LOCAL:
     case VariableLocation::CONTEXT: {
       // Local var, const, or let variable or context variable.
-      return jsgraph()->BooleanConstant(variable->HasThisName(isolate()));
+      return jsgraph()->BooleanConstant(variable->is_this());
     }
     case VariableLocation::LOOKUP: {
       // Dynamic lookup of context variable (anywhere in the chain).
       Node* name = jsgraph()->Constant(variable->name());
       const Operator* op =
           javascript()->CallRuntime(Runtime::kDeleteLookupSlot);
       Node* result = NewNode(op, name);
       PrepareFrameState(result, bailout_id, combine);
       return result;
     }
@@ skipping 903 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