Line data    Source code

       1             : // Copyright 2015 the V8 project authors. All rights reserved.
       2             : // Use of this source code is governed by a BSD-style license that can be
       3             : // found in the LICENSE file.
       4             : 
       5             : #ifndef V8_COMPILER_DEAD_CODE_ELIMINATION_H_
       6             : #define V8_COMPILER_DEAD_CODE_ELIMINATION_H_
       7             : 
       8             : #include "src/base/compiler-specific.h"
       9             : #include "src/compiler/graph-reducer.h"
      10             : #include "src/globals.h"
      11             : 
      12             : namespace v8 {
      13             : namespace internal {
      14             : namespace compiler {
      15             : 
      16             : // Forward declarations.
      17             : class CommonOperatorBuilder;
      18             : 
      19             : 
      20             : // Propagates {Dead} control through the graph and thereby removes dead code.
      21             : // Note that this does not include trimming dead uses from the graph, and it
      22             : // also does not include detecting dead code by any other means than seeing a
      23             : // {Dead} control input; that is left to other reducers.
      24             : class V8_EXPORT_PRIVATE DeadCodeElimination final
      25             :     : public NON_EXPORTED_BASE(AdvancedReducer) {
      26             :  public:
      27             :   DeadCodeElimination(Editor* editor, Graph* graph,
      28             :                       CommonOperatorBuilder* common);
      29     2446041 :   ~DeadCodeElimination() final {}
      30             : 
      31             :   Reduction Reduce(Node* node) final;
      32             : 
      33             :  private:
      34             :   Reduction ReduceEnd(Node* node);
      35             :   Reduction ReduceLoopOrMerge(Node* node);
      36             :   Reduction ReduceLoopExit(Node* node);
      37             :   Reduction ReduceNode(Node* node);
      38             : 
      39             :   Reduction RemoveLoopExit(Node* node);
      40             : 
      41             :   void TrimMergeOrPhi(Node* node, int size);
      42             : 
      43             :   Graph* graph() const { return graph_; }
      44             :   CommonOperatorBuilder* common() const { return common_; }
      45             :   Node* dead() const { return dead_; }
      46             : 
      47             :   Graph* const graph_;
      48             :   CommonOperatorBuilder* const common_;
      49             :   Node* const dead_;
      50             : 
      51             :   DISALLOW_COPY_AND_ASSIGN(DeadCodeElimination);
      52             : };
      53             : 
      54             : }  // namespace compiler
      55             : }  // namespace internal
      56             : }  // namespace v8
      57             : 
      58             : #endif  // V8_COMPILER_DEAD_CODE_ELIMINATION_H_