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             : #include "src/compiler/graph-trimmer.h"
       6             : 
       7             : #include "src/compiler/graph.h"
       8             : 
       9             : namespace v8 {
      10             : namespace internal {
      11             : namespace compiler {
      12             : 
      13    10021074 : GraphTrimmer::GraphTrimmer(Zone* zone, Graph* graph)
      14     5010488 :     : graph_(graph), is_live_(graph, 2), live_(zone) {
      15     5010586 :   live_.reserve(graph->NodeCount());
      16     5010851 : }
      17             : 
      18             : 
      19             : GraphTrimmer::~GraphTrimmer() = default;
      20             : 
      21             : 
      22     5010727 : void GraphTrimmer::TrimGraph() {
      23             :   // Mark end node as live.
      24     5010727 :   MarkAsLive(graph()->end());
      25             :   // Compute transitive closure of live nodes.
      26   607452975 :   for (size_t i = 0; i < live_.size(); ++i) {
      27   607453758 :     Node* const live = live_[i];
      28  1286859248 :     for (Node* const input : live->inputs()) MarkAsLive(input);
      29             :   }
      30             :   // Remove dead->live edges.
      31   607458263 :   for (Node* const live : live_) {
      32             :     DCHECK(IsLive(live));
      33  2062535789 :     for (Edge edge : live->use_edges()) {
      34             :       Node* const user = edge.from();
      35   730044494 :       if (!IsLive(user)) {
      36    45635459 :         if (FLAG_trace_turbo_trimming) {
      37           0 :           StdoutStream{} << "DeadLink: " << *user << "(" << edge.index()
      38           0 :                          << ") -> " << *live << std::endl;
      39             :         }
      40    45635459 :         edge.UpdateTo(nullptr);
      41             :       }
      42             :     }
      43             :   }
      44     5010863 : }
      45             : 
      46             : }  // namespace compiler
      47             : }  // namespace internal
      48      183867 : }  // namespace v8