1 /* 2 * Copyright (c) 2011, 2015, 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.nodes.extended; 24 25 import static org.graalvm.compiler.nodeinfo.InputType.Anchor; 26 import static org.graalvm.compiler.nodeinfo.InputType.Guard; 27 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0; 28 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0; 29 30 import org.graalvm.compiler.core.common.type.StampFactory; 31 import org.graalvm.compiler.graph.NodeClass; 32 import org.graalvm.compiler.graph.spi.Simplifiable; 33 import org.graalvm.compiler.graph.spi.SimplifierTool; 34 import org.graalvm.compiler.nodeinfo.NodeInfo; 35 import org.graalvm.compiler.nodes.AbstractBeginNode; 36 import org.graalvm.compiler.nodes.FixedNode; 37 import org.graalvm.compiler.nodes.FixedWithNextNode; 38 import org.graalvm.compiler.nodes.GuardNode; 39 import org.graalvm.compiler.nodes.ValueNode; 40 import org.graalvm.compiler.nodes.calc.IsNullNode; 41 import org.graalvm.compiler.nodes.memory.FixedAccessNode; 42 import org.graalvm.compiler.nodes.spi.LIRLowerable; 43 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; 44 import org.graalvm.compiler.nodes.spi.Virtualizable; 45 import org.graalvm.compiler.nodes.spi.VirtualizerTool; 46 import org.graalvm.compiler.nodes.util.GraphUtil; 47 import org.graalvm.compiler.nodes.virtual.VirtualObjectNode; 48 49 /** 50 * The ValueAnchor instruction keeps non-CFG (floating) nodes above a certain point in the graph. 51 */ 52 @NodeInfo(allowedUsageTypes = {Anchor, Guard}, cycles = CYCLES_0, size = SIZE_0) 53 public final class ValueAnchorNode extends FixedWithNextNode implements LIRLowerable, Simplifiable, Virtualizable, AnchoringNode, GuardingNode { 54 55 public static final NodeClass<ValueAnchorNode> TYPE = NodeClass.create(ValueAnchorNode.class); 56 @OptionalInput(Guard) ValueNode anchored; 57 58 public ValueAnchorNode(ValueNode value) { 59 super(TYPE, StampFactory.forVoid()); 60 this.anchored = value; 61 } 62 63 @Override 64 public void generate(NodeLIRBuilderTool gen) { 65 // Nothing to emit, since this node is used for structural purposes only. 66 } 67 68 public ValueNode getAnchoredNode() { 69 return anchored; 70 } 71 72 @Override 73 public void simplify(SimplifierTool tool) { 74 while (next() instanceof ValueAnchorNode) { 75 ValueAnchorNode nextAnchor = (ValueAnchorNode) next(); 76 if (nextAnchor.anchored == anchored || nextAnchor.anchored == null) { 77 // two anchors for the same anchored -> coalesce 78 // nothing anchored on the next anchor -> coalesce 79 nextAnchor.replaceAtUsages(this); 80 GraphUtil.removeFixedWithUnusedInputs(nextAnchor); 81 } else { 82 break; 83 } 84 } 85 if (tool.allUsagesAvailable() && hasNoUsages() && next() instanceof FixedAccessNode) { 86 FixedAccessNode currentNext = (FixedAccessNode) next(); 87 if (currentNext.getGuard() == anchored) { 88 GraphUtil.removeFixedWithUnusedInputs(this); 89 return; 90 } else if (currentNext.getGuard() == null && anchored instanceof GuardNode && ((GuardNode) anchored).getCondition() instanceof IsNullNode) { 91 // coalesce null check guards into subsequent read/write 92 currentNext.setGuard((GuardingNode) anchored); 93 tool.addToWorkList(next()); 94 return; 95 } 96 } 97 98 if (anchored != null && (anchored.isConstant() || anchored instanceof FixedNode)) { 99 // anchoring fixed nodes and constants is useless 100 removeAnchoredNode(); 101 } 102 103 if (anchored == null && hasNoUsages()) { 104 // anchor is not necessary any more => remove. 105 GraphUtil.removeFixedWithUnusedInputs(this); 106 } 107 } 108 109 @Override 110 public void virtualize(VirtualizerTool tool) { 111 if (anchored == null || anchored instanceof AbstractBeginNode) { 112 tool.delete(); 113 } else { 114 ValueNode alias = tool.getAlias(anchored); 115 if (alias instanceof VirtualObjectNode) { 116 tool.delete(); 117 } 118 } 119 } 120 121 public void removeAnchoredNode() { 122 this.updateUsages(anchored, null); 123 this.anchored = null; 124 } 125 }