| /* |
| * Copyright (c) 2011, 2016, 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 org.graalvm.compiler.phases.common; |
| |
| import static org.graalvm.compiler.phases.common.DeadCodeEliminationPhase.Optionality.Optional; |
| |
| import java.util.List; |
| |
| import org.graalvm.compiler.debug.Debug; |
| import org.graalvm.compiler.graph.Node; |
| import org.graalvm.compiler.graph.spi.SimplifierTool; |
| import org.graalvm.compiler.nodeinfo.InputType; |
| import org.graalvm.compiler.nodes.AbstractBeginNode; |
| import org.graalvm.compiler.nodes.AbstractEndNode; |
| import org.graalvm.compiler.nodes.AbstractMergeNode; |
| import org.graalvm.compiler.nodes.ConstantNode; |
| import org.graalvm.compiler.nodes.ControlSplitNode; |
| import org.graalvm.compiler.nodes.DeoptimizeNode; |
| import org.graalvm.compiler.nodes.EndNode; |
| import org.graalvm.compiler.nodes.FixedGuardNode; |
| import org.graalvm.compiler.nodes.FixedNode; |
| import org.graalvm.compiler.nodes.FixedWithNextNode; |
| import org.graalvm.compiler.nodes.GuardNode; |
| import org.graalvm.compiler.nodes.IfNode; |
| import org.graalvm.compiler.nodes.LogicNode; |
| import org.graalvm.compiler.nodes.LoopExitNode; |
| import org.graalvm.compiler.nodes.ProxyNode; |
| import org.graalvm.compiler.nodes.StructuredGraph; |
| import org.graalvm.compiler.nodes.ValueNode; |
| import org.graalvm.compiler.nodes.ValuePhiNode; |
| import org.graalvm.compiler.nodes.calc.CompareNode; |
| import org.graalvm.compiler.nodes.spi.LoweringProvider; |
| import org.graalvm.compiler.nodes.util.GraphUtil; |
| import org.graalvm.compiler.phases.BasePhase; |
| import org.graalvm.compiler.phases.tiers.PhaseContext; |
| |
| import jdk.vm.ci.meta.Constant; |
| import jdk.vm.ci.meta.DeoptimizationAction; |
| import jdk.vm.ci.meta.DeoptimizationReason; |
| import jdk.vm.ci.meta.JavaConstant; |
| |
| /** |
| * 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 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(), d.getSpeculation(), graph, context != null ? context.getLowerer() : null); |
| } |
| |
| 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.getSpeculation(), fixedGuard.graph(), context.getLowerer()); |
| } |
| } |
| } |
| |
| private void visitDeoptBegin(AbstractBeginNode deoptBegin, DeoptimizationAction deoptAction, DeoptimizationReason deoptReason, JavaConstant speculation, StructuredGraph graph, |
| LoweringProvider loweringProvider) { |
| if (deoptBegin.predecessor() instanceof AbstractBeginNode) { |
| /* |
| * Walk up chains of LoopExitNodes to the "real" BeginNode that leads to deoptimization. |
| */ |
| visitDeoptBegin((AbstractBeginNode) deoptBegin.predecessor(), deoptAction, deoptReason, speculation, graph, loweringProvider); |
| return; |
| } |
| |
| 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, speculation, graph, loweringProvider); |
| } |
| assert next.isAlive(); |
| AbstractBeginNode newBeginNode = findBeginNode(next); |
| visitDeoptBegin(newBeginNode, deoptAction, deoptReason, speculation, graph, loweringProvider); |
| 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, speculation, 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); |
| |
| Node newGuard = guard; |
| if (survivingSuccessor instanceof LoopExitNode) { |
| newGuard = ProxyNode.forGuard(guard, (LoopExitNode) survivingSuccessor, graph); |
| } |
| survivingSuccessor.replaceAtUsages(InputType.Guard, newGuard); |
| |
| 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); |
| SimplifierTool simplifierTool = GraphUtil.getDefaultSimplifier(null, null, null, false, graph.getAssumptions(), loweringProvider); |
| 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, speculation)); |
| deoptPred.setNext(newDeoptNode); |
| assert deoptPred == newDeoptNode.predecessor(); |
| GraphUtil.killCFG(next); |
| } |
| } |
| } |
