Mercurial > hg > truffle
view graal/com.oracle.graal.phases.common/src/com/oracle/graal/phases/common/ConvertDeoptimizeToGuardPhase.java @ 19540:9a749d774c73
Refactor ConvertDeoptimizeToGuardPhase.
author | Thomas Wuerthinger <thomas.wuerthinger@oracle.com> |
---|---|
date | Sun, 22 Feb 2015 19:31:57 +0100 |
parents | caad3adc5fde |
children | 2e0a55d381ea |
line wrap: on
line source
/* * Copyright (c) 2011, 2014, 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.Optionality.*; import java.util.*; import com.oracle.graal.api.meta.*; import com.oracle.graal.debug.*; import com.oracle.graal.graph.*; import com.oracle.graal.graph.spi.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.calc.*; import com.oracle.graal.nodes.util.*; import com.oracle.graal.phases.*; import com.oracle.graal.phases.tiers.*; /** * 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 BasePhase<PhaseContext> { private SimplifierTool simplifierTool = GraphUtil.getDefaultSimplifier(null, null, false); private static AbstractBeginNode findBeginNode(FixedNode startNode) { return GraphUtil.predecessorIterable(startNode).filter(AbstractBeginNode.class).first(); } @Override protected void run(final StructuredGraph graph, PhaseContext context) { assert graph.hasValueProxies() : "ConvertDeoptimizeToGuardPhase always creates proxies"; if (graph.getNodes(DeoptimizeNode.TYPE).isEmpty()) { return; } for (DeoptimizeNode d : graph.getNodes(DeoptimizeNode.TYPE)) { assert d.isAlive(); visitDeoptBegin(AbstractBeginNode.prevBegin(d), d.action(), d.reason(), graph); } if (context != null) { for (FixedGuardNode fixedGuard : graph.getNodes(FixedGuardNode.TYPE)) { trySplitFixedGuard(fixedGuard, context); } } new DeadCodeEliminationPhase(Optional).apply(graph); } private void trySplitFixedGuard(FixedGuardNode fixedGuard, PhaseContext context) { LogicNode condition = fixedGuard.condition(); if (condition instanceof CompareNode) { CompareNode compare = (CompareNode) condition; ValueNode x = compare.getX(); ValuePhiNode xPhi = (x instanceof ValuePhiNode) ? (ValuePhiNode) x : null; if (x instanceof ConstantNode || xPhi != null) { ValueNode y = compare.getY(); ValuePhiNode yPhi = (y instanceof ValuePhiNode) ? (ValuePhiNode) y : null; if (y instanceof ConstantNode || yPhi != null) { processFixedGuardAndPhis(fixedGuard, context, compare, x, xPhi, y, yPhi); } } } } private void processFixedGuardAndPhis(FixedGuardNode fixedGuard, PhaseContext context, CompareNode compare, ValueNode x, ValuePhiNode xPhi, ValueNode y, ValuePhiNode yPhi) { AbstractBeginNode pred = AbstractBeginNode.prevBegin(fixedGuard); if (pred instanceof AbstractMergeNode) { AbstractMergeNode merge = (AbstractMergeNode) pred; if (xPhi != null && xPhi.merge() != merge) { return; } if (yPhi != null && yPhi.merge() != merge) { return; } processFixedGuardAndMerge(fixedGuard, context, compare, x, xPhi, y, yPhi, merge); } } private void processFixedGuardAndMerge(FixedGuardNode fixedGuard, PhaseContext context, CompareNode compare, ValueNode x, ValuePhiNode xPhi, ValueNode y, ValuePhiNode yPhi, AbstractMergeNode merge) { List<EndNode> mergePredecessors = merge.cfgPredecessors().snapshot(); for (int i = 0; i < mergePredecessors.size(); ++i) { AbstractEndNode mergePredecessor = mergePredecessors.get(i); if (!mergePredecessor.isAlive()) { break; } Constant xs; if (xPhi == null) { xs = x.asConstant(); } else { xs = xPhi.valueAt(mergePredecessor).asConstant(); } Constant ys; if (yPhi == null) { ys = y.asConstant(); } else { ys = yPhi.valueAt(mergePredecessor).asConstant(); } if (xs != null && ys != null && compare.condition().foldCondition(xs, ys, context.getConstantReflection(), compare.unorderedIsTrue()) == fixedGuard.isNegated()) { visitDeoptBegin(AbstractBeginNode.prevBegin(mergePredecessor), fixedGuard.getAction(), fixedGuard.getReason(), fixedGuard.graph()); } } } private void visitDeoptBegin(AbstractBeginNode deoptBegin, DeoptimizationAction deoptAction, DeoptimizationReason deoptReason, StructuredGraph graph) { if (deoptBegin instanceof AbstractMergeNode) { AbstractMergeNode mergeNode = (AbstractMergeNode) deoptBegin; Debug.log("Visiting %s", mergeNode); FixedNode next = mergeNode.next(); while (mergeNode.isAlive()) { AbstractEndNode end = mergeNode.forwardEnds().first(); AbstractBeginNode newBeginNode = findBeginNode(end); visitDeoptBegin(newBeginNode, deoptAction, deoptReason, graph); } assert next.isAlive(); AbstractBeginNode newBeginNode = findBeginNode(next); visitDeoptBegin(newBeginNode, deoptAction, deoptReason, graph); 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, deoptReason, deoptAction, 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 deopt on %-5s branch of %s to guard for remaining branch %s.", deoptBegin == ifNode.trueSuccessor() ? "true" : "false", ifNode, otherBegin); FixedNode next = pred.next(); pred.setNext(guard); guard.setNext(next); survivingSuccessor.simplify(simplifierTool); 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 instanceof DeoptimizeNode)) { DeoptimizeNode newDeoptNode = graph.add(new DeoptimizeNode(deoptAction, deoptReason)); deoptPred.setNext(newDeoptNode); assert deoptPred == newDeoptNode.predecessor(); GraphUtil.killCFG(next); } } }