Mercurial > hg > truffle
view graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/ConvertDeoptimizeToGuardPhase.java @ 12372:2dfccd93510a
Merge
author | Christos Kotselidis <christos.kotselidis@oracle.com> |
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date | Fri, 11 Oct 2013 21:41:42 +0200 |
parents | c66cdfb7445b |
children | 53297646b011 |
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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 java.util.*; import com.oracle.graal.debug.*; import com.oracle.graal.graph.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.util.*; import com.oracle.graal.phases.*; /** * This phase will find branches which always end with a {@link DeoptimizeNode} and replace their * {@link ControlSplitNode ControlSplitNodes} with {@link FixedGuardNode FixedGuardNodes}. * * This is useful because {@link FixedGuardNode FixedGuardNodes} will be lowered to * {@link GuardNode GuardNodes} which can later be optimized more aggressively than control-flow * constructs. * * This is currently only done for branches that start from a {@link IfNode}. If it encounters a * branch starting at an other kind of {@link ControlSplitNode}, it will only bring the * {@link DeoptimizeNode} as close to the {@link ControlSplitNode} as possible. * */ public class ConvertDeoptimizeToGuardPhase extends Phase { private static AbstractBeginNode findBeginNode(Node startNode) { Node n = startNode; while (true) { if (n instanceof AbstractBeginNode) { return (AbstractBeginNode) n; } else { n = n.predecessor(); } } } @Override protected void run(final StructuredGraph graph) { if (graph.getNodes(DeoptimizeNode.class).isEmpty()) { return; } for (DeoptimizeNode d : graph.getNodes(DeoptimizeNode.class)) { assert d.isAlive(); visitDeoptBegin(findBeginNode(d), d, graph); } new DeadCodeEliminationPhase().apply(graph); } private void visitDeoptBegin(AbstractBeginNode deoptBegin, DeoptimizeNode deopt, StructuredGraph graph) { if (deoptBegin instanceof MergeNode) { MergeNode mergeNode = (MergeNode) deoptBegin; Debug.log("Visiting %s followed by %s", mergeNode, deopt); List<AbstractBeginNode> begins = new ArrayList<>(); for (AbstractEndNode end : mergeNode.forwardEnds()) { AbstractBeginNode newBeginNode = findBeginNode(end); assert !begins.contains(newBeginNode); begins.add(newBeginNode); } for (AbstractBeginNode begin : begins) { assert !begin.isDeleted(); visitDeoptBegin(begin, deopt, graph); } assert mergeNode.isDeleted(); return; } else if (deoptBegin.predecessor() instanceof IfNode) { IfNode ifNode = (IfNode) deoptBegin.predecessor(); AbstractBeginNode otherBegin = ifNode.trueSuccessor(); LogicNode conditionNode = ifNode.condition(); FixedGuardNode guard = graph.add(new FixedGuardNode(conditionNode, deopt.reason(), deopt.action(), deoptBegin == ifNode.trueSuccessor())); FixedWithNextNode pred = (FixedWithNextNode) ifNode.predecessor(); AbstractBeginNode survivingSuccessor; if (deoptBegin == ifNode.trueSuccessor()) { survivingSuccessor = ifNode.falseSuccessor(); } else { survivingSuccessor = ifNode.trueSuccessor(); } graph.removeSplitPropagate(ifNode, survivingSuccessor); ProxyNode proxyGuard = null; for (Node n : survivingSuccessor.usages().snapshot()) { if (n instanceof GuardNode || n instanceof ProxyNode) { // Keep wired to the begin node. } else { // Rewire to the fixed guard. if (survivingSuccessor instanceof LoopExitNode) { if (proxyGuard == null) { proxyGuard = ProxyNode.forGuard(guard, survivingSuccessor, graph); } n.replaceFirstInput(survivingSuccessor, proxyGuard); } else { n.replaceFirstInput(survivingSuccessor, guard); } } } Debug.log("Converting %s on %-5s branch of %s to guard for remaining branch %s.", deopt, deoptBegin == ifNode.trueSuccessor() ? "true" : "false", ifNode, otherBegin); FixedNode next = pred.next(); pred.setNext(guard); guard.setNext(next); return; } // We could not convert the control split - at least cut off control flow after the split. FixedWithNextNode deoptPred = deoptBegin; FixedNode next = deoptPred.next(); if (next != deopt) { DeoptimizeNode newDeoptNode = (DeoptimizeNode) deopt.clone(graph); deoptPred.setNext(newDeoptNode); assert deoptPred == newDeoptNode.predecessor(); GraphUtil.killCFG(next); } } }