Implement representation selection as part of SimplifiedLowering. Representation selection also req…

src/compiler/lowering-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/graph-inl.h"
 #include "src/compiler/lowering-builder.h"
 #include "src/compiler/node-aux-data-inl.h"
 #include "src/compiler/node-properties-inl.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
 
 class LoweringBuilder::NodeVisitor : public NullNodeVisitor {
  public:
   explicit NodeVisitor(LoweringBuilder* lowering) : lowering_(lowering) {}
 
   GenericGraphVisit::Control Post(Node* node) {
-    SourcePositionTable::Scope pos(lowering_->source_positions_, node);
-    lowering_->Lower(node);
+    if (lowering_->source_positions_ != NULL) {
+      SourcePositionTable::Scope pos(lowering_->source_positions_, node);
+      lowering_->Lower(node);
+    } else {
+      lowering_->Lower(node);
+    }
     return GenericGraphVisit::CONTINUE;
   }
 
  private:
   LoweringBuilder* lowering_;
 };
 
 
 LoweringBuilder::LoweringBuilder(Graph* graph,
                                  SourcePositionTable* source_positions)
     : graph_(graph), source_positions_(source_positions) {}
 
 
 void LoweringBuilder::LowerAllNodes() {
   NodeVisitor visitor(this);
   graph()->VisitNodeInputsFromEnd(&visitor);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8