| // Copyright 2015 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-trimmer.h" |
| |
| #include "src/compiler/graph.h" |
| |
| namespace v8 { |
| namespace internal { |
| namespace compiler { |
| |
| GraphTrimmer::GraphTrimmer(Zone* zone, Graph* graph) |
| : graph_(graph), is_live_(graph, 2), live_(zone) { |
| live_.reserve(graph->NodeCount()); |
| } |
| |
| |
| GraphTrimmer::~GraphTrimmer() {} |
| |
| |
| void GraphTrimmer::TrimGraph() { |
| // Mark end node as live. |
| MarkAsLive(graph()->end()); |
| // Compute transitive closure of live nodes. |
| for (size_t i = 0; i < live_.size(); ++i) { |
| Node* const live = live_[i]; |
| for (Node* const input : live->inputs()) MarkAsLive(input); |
| } |
| // Remove dead->live edges. |
| for (Node* const live : live_) { |
| DCHECK(IsLive(live)); |
| for (Edge edge : live->use_edges()) { |
| Node* const user = edge.from(); |
| if (!IsLive(user)) { |
| if (FLAG_trace_turbo_trimming) { |
| OFStream os(stdout); |
| os << "DeadLink: " << *user << "(" << edge.index() << ") -> " << *live |
| << std::endl; |
| } |
| edge.UpdateTo(nullptr); |
| } |
| } |
| } |
| } |
| |
| } // namespace compiler |
| } // namespace internal |
| } // namespace v8 |