Mercurial > hg > graal-compiler
view graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/DeadCodeEliminationPhase.java @ 17376:9928ad27a80e
OopRecorder should check for duplicates
author | Tom Rodriguez <tom.rodriguez@oracle.com> |
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date | Wed, 08 Oct 2014 11:48:00 -0700 |
parents | 86888df288ec |
children | ecb9d0cedbab |
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/* * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.graal.phases.common; import static com.oracle.graal.phases.common.DeadCodeEliminationPhase.Options.*; import com.oracle.graal.debug.*; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.*; import com.oracle.graal.options.*; import com.oracle.graal.phases.*; public class DeadCodeEliminationPhase extends Phase { public static class Options { // @formatter:off @Option(help = "Disable optional dead code eliminations") public static final OptionValue<Boolean> ReduceDCE = new OptionValue<>(true); // @formatter:on } // Metrics private static final DebugMetric metricNodesRemoved = Debug.metric("NodesRemoved"); public enum Optionality { Optional, Required; } /** * Creates a dead code elimination phase that will be run irrespective of * {@link Options#ReduceDCE}. */ public DeadCodeEliminationPhase() { this(Optionality.Required); } /** * Creates a dead code elimination phase that will be run only if it is * {@linkplain Optionality#Required non-optional} or {@link Options#ReduceDCE} is false. */ public DeadCodeEliminationPhase(Optionality optionality) { this.optional = optionality == Optionality.Optional; } private final boolean optional; @Override public void run(StructuredGraph graph) { if (optional && ReduceDCE.getValue()) { return; } NodeFlood flood = graph.createNodeFlood(); flood.add(graph.start()); iterateSuccessors(flood); disconnectCFGNodes(flood, graph); iterateInputs(flood, graph); deleteNodes(flood, graph); // remove chained Merges for (MergeNode merge : graph.getNodes(MergeNode.class)) { if (merge.forwardEndCount() == 1 && !(merge instanceof LoopBeginNode)) { graph.reduceTrivialMerge(merge); } } } private static void iterateSuccessors(NodeFlood flood) { for (Node current : flood) { if (current instanceof AbstractEndNode) { AbstractEndNode end = (AbstractEndNode) current; flood.add(end.merge()); } else { for (Node successor : current.successors()) { flood.add(successor); } } } } private static void disconnectCFGNodes(NodeFlood flood, StructuredGraph graph) { for (AbstractEndNode node : graph.getNodes(AbstractEndNode.class)) { if (!flood.isMarked(node)) { MergeNode merge = node.merge(); if (merge != null && flood.isMarked(merge)) { // We are a dead end node leading to a live merge. merge.removeEnd(node); } } } for (LoopBeginNode loop : graph.getNodes(LoopBeginNode.class)) { if (flood.isMarked(loop)) { boolean reachable = false; for (LoopEndNode end : loop.loopEnds()) { if (flood.isMarked(end)) { reachable = true; break; } } if (!reachable) { Debug.log("Removing loop with unreachable end: %s", loop); for (LoopEndNode end : loop.loopEnds().snapshot()) { loop.removeEnd(end); } graph.reduceDegenerateLoopBegin(loop); } } } } private static void deleteNodes(NodeFlood flood, StructuredGraph graph) { for (Node node : graph.getNodes()) { if (!flood.isMarked(node)) { node.clearInputs(); node.clearSuccessors(); } } for (Node node : graph.getNodes()) { if (!flood.isMarked(node)) { metricNodesRemoved.increment(); node.safeDelete(); } } } private static void iterateInputs(NodeFlood flood, StructuredGraph graph) { for (Node node : graph.getNodes()) { if (flood.isMarked(node)) { for (Node input : node.inputs()) { flood.add(input); } } } for (Node current : flood) { for (Node input : current.inputs()) { flood.add(input); } } } }