Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 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 | GraphTrimmer::GraphTrimmer(Zone* zone, Graph* graph) |
| 14 | : graph_(graph), is_live_(graph, 2), live_(zone) { |
| 15 | live_.reserve(graph->NodeCount()); |
| 16 | } |
| 17 | |
| 18 | |
| 19 | GraphTrimmer::~GraphTrimmer() {} |
| 20 | |
| 21 | |
| 22 | void GraphTrimmer::TrimGraph() { |
| 23 | // Mark end node as live. |
| 24 | MarkAsLive(graph()->end()); |
| 25 | // Compute transitive closure of live nodes. |
| 26 | for (size_t i = 0; i < live_.size(); ++i) { |
Ben Murdoch | 097c5b2 | 2016-05-18 11:27:45 +0100 | [diff] [blame] | 27 | Node* const live = live_[i]; |
| 28 | for (Node* const input : live->inputs()) MarkAsLive(input); |
Ben Murdoch | 4a90d5f | 2016-03-22 12:00:34 +0000 | [diff] [blame] | 29 | } |
| 30 | // Remove dead->live edges. |
| 31 | for (Node* const live : live_) { |
| 32 | DCHECK(IsLive(live)); |
| 33 | for (Edge edge : live->use_edges()) { |
| 34 | Node* const user = edge.from(); |
| 35 | if (!IsLive(user)) { |
| 36 | if (FLAG_trace_turbo_reduction) { |
| 37 | OFStream os(stdout); |
| 38 | os << "DeadLink: " << *user << "(" << edge.index() << ") -> " << *live |
| 39 | << std::endl; |
| 40 | } |
| 41 | edge.UpdateTo(nullptr); |
| 42 | } |
| 43 | } |
| 44 | } |
| 45 | } |
| 46 | |
| 47 | } // namespace compiler |
| 48 | } // namespace internal |
| 49 | } // namespace v8 |