1 /* 2 * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.phases.common; 24 25 import java.util.List; 26 import java.util.Set; 27 28 import org.graalvm.compiler.graph.Node; 29 import org.graalvm.compiler.nodes.AbstractMergeNode; 30 import org.graalvm.compiler.nodes.FixedNode; 31 import org.graalvm.compiler.nodes.StartNode; 32 import org.graalvm.compiler.nodes.StructuredGraph; 33 import org.graalvm.compiler.nodes.ValueNode; 34 import org.graalvm.compiler.nodes.extended.ValueAnchorNode; 35 import org.graalvm.compiler.phases.Phase; 36 import org.graalvm.compiler.phases.graph.MergeableState; 37 import org.graalvm.compiler.phases.graph.SinglePassNodeIterator; 38 39 /** 40 * This phase performs a bit of hygiene on {@link ValueAnchorNode} by removing inputs that have 41 * already been anchored in a dominating value anchor. Value anchors that lose their last input, 42 * have no usages and are not marked as permanent are removed. 43 */ 44 public class ValueAnchorCleanupPhase extends Phase { 45 46 private static class State extends MergeableState<State> implements Cloneable { 47 48 private final Set<Node> anchoredValues; 49 50 State() { 51 anchoredValues = Node.newSet(); 52 } 53 54 State(State other) { 55 anchoredValues = Node.newSet(other.anchoredValues); 56 } 57 58 @Override 59 public boolean merge(AbstractMergeNode merge, List<State> withStates) { 60 for (State other : withStates) { 61 anchoredValues.retainAll(other.anchoredValues); 62 } 63 return true; 64 } 65 66 @Override 67 public State clone() { 68 return new State(this); 69 } 70 } 71 72 private static class CleanupValueAnchorsClosure extends SinglePassNodeIterator<State> { 73 74 CleanupValueAnchorsClosure(StartNode start) { 75 super(start, new State()); 76 } 77 78 @Override 79 protected void node(FixedNode node) { 80 if (node instanceof ValueAnchorNode) { 81 ValueAnchorNode anchor = (ValueAnchorNode) node; 82 ValueNode anchored = anchor.getAnchoredNode(); 83 if (anchored != null) { 84 if (state.anchoredValues.contains(anchored)) { 85 anchor.removeAnchoredNode(); 86 } else { 87 state.anchoredValues.add(anchored); 88 } 89 } 90 if (anchor.getAnchoredNode() == null && anchor.hasNoUsages()) { 91 node.graph().removeFixed(anchor); 92 } 93 } 94 } 95 } 96 97 @Override 98 protected void run(StructuredGraph graph) { 99 CleanupValueAnchorsClosure closure = new CleanupValueAnchorsClosure(graph.start()); 100 closure.apply(); 101 } 102 }