1 /* 2 * Copyright (c) 2013, 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 24 25 package org.graalvm.compiler.word; 26 27 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1; 28 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1; 29 30 import org.graalvm.compiler.core.common.LIRKind; 31 import org.graalvm.compiler.core.common.type.AbstractPointerStamp; 32 import org.graalvm.compiler.core.common.type.IntegerStamp; 33 import org.graalvm.compiler.core.common.type.ObjectStamp; 34 import org.graalvm.compiler.core.common.type.Stamp; 35 import org.graalvm.compiler.core.common.type.StampFactory; 36 import org.graalvm.compiler.graph.Node; 37 import org.graalvm.compiler.graph.NodeClass; 38 import org.graalvm.compiler.graph.spi.Canonicalizable; 39 import org.graalvm.compiler.graph.spi.CanonicalizerTool; 40 import org.graalvm.compiler.lir.ConstantValue; 41 import org.graalvm.compiler.nodeinfo.NodeInfo; 42 import org.graalvm.compiler.nodes.ConstantNode; 43 import org.graalvm.compiler.nodes.FixedWithNextNode; 44 import org.graalvm.compiler.nodes.NodeView; 45 import org.graalvm.compiler.nodes.ValueNode; 46 import org.graalvm.compiler.nodes.spi.LIRLowerable; 47 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; 48 import org.graalvm.compiler.nodes.type.NarrowOopStamp; 49 50 import jdk.vm.ci.meta.AllocatableValue; 51 import jdk.vm.ci.meta.JavaConstant; 52 import jdk.vm.ci.meta.JavaKind; 53 import jdk.vm.ci.meta.Value; 54 import jdk.vm.ci.meta.ValueKind; 55 56 /** 57 * Casts between Word and Object exposed by the {@link Word#fromAddress}, 58 * {@link Word#objectToTrackedPointer}, {@link Word#objectToUntrackedPointer} and 59 * {@link Word#toObject()} operations. It has an impact on the pointer maps for the GC, so it must 60 * not be scheduled or optimized away. 61 */ 62 @NodeInfo(cycles = CYCLES_1, size = SIZE_1) 63 public final class WordCastNode extends FixedWithNextNode implements LIRLowerable, Canonicalizable { 64 65 public static final NodeClass<WordCastNode> TYPE = NodeClass.create(WordCastNode.class); 66 67 @Input ValueNode input; 68 private final boolean trackedPointer; 69 70 public static WordCastNode wordToObject(ValueNode input, JavaKind wordKind) { 71 assert input.getStackKind() == wordKind; 72 return new WordCastNode(objectStampFor(input), input); 73 } 74 75 public static WordCastNode wordToObjectNonNull(ValueNode input, JavaKind wordKind) { 76 assert input.getStackKind() == wordKind; 77 return new WordCastNode(StampFactory.objectNonNull(), input); 78 } 79 80 public static WordCastNode wordToNarrowObject(ValueNode input, NarrowOopStamp stamp) { 81 return new WordCastNode(stamp, input); 82 } 83 84 public static WordCastNode addressToWord(ValueNode input, JavaKind wordKind) { 85 assert input.stamp(NodeView.DEFAULT) instanceof AbstractPointerStamp; 86 return new WordCastNode(StampFactory.forKind(wordKind), input); 87 } 88 89 public static WordCastNode objectToTrackedPointer(ValueNode input, JavaKind wordKind) { 90 assert input.stamp(NodeView.DEFAULT) instanceof ObjectStamp; 91 return new WordCastNode(StampFactory.forKind(wordKind), input); 92 } 93 94 public static WordCastNode objectToUntrackedPointer(ValueNode input, JavaKind wordKind) { 95 assert input.stamp(NodeView.DEFAULT) instanceof ObjectStamp; 96 return new WordCastNode(StampFactory.forKind(wordKind), input, false); 97 } 98 99 public static WordCastNode narrowOopToUntrackedWord(ValueNode input, JavaKind wordKind) { 100 assert input.stamp(NodeView.DEFAULT) instanceof NarrowOopStamp; 101 return new WordCastNode(StampFactory.forKind(wordKind), input, false); 102 } 103 104 private WordCastNode(Stamp stamp, ValueNode input) { 105 this(stamp, input, true); 106 } 107 108 protected WordCastNode(Stamp stamp, ValueNode input, boolean trackedPointer) { 109 super(TYPE, stamp); 110 this.input = input; 111 this.trackedPointer = trackedPointer; 112 } 113 114 public ValueNode getInput() { 115 return input; 116 } 117 118 private static boolean isZeroConstant(ValueNode value) { 119 JavaConstant constant = value.asJavaConstant(); 120 return constant.getJavaKind().isNumericInteger() && constant.asLong() == 0; 121 } 122 123 private static Stamp objectStampFor(ValueNode input) { 124 Stamp inputStamp = input.stamp(NodeView.DEFAULT); 125 if (inputStamp instanceof AbstractPointerStamp) { 126 AbstractPointerStamp pointerStamp = (AbstractPointerStamp) inputStamp; 127 if (pointerStamp.alwaysNull()) { 128 return StampFactory.alwaysNull(); 129 } else if (pointerStamp.nonNull()) { 130 return StampFactory.objectNonNull(); 131 } 132 } else if (inputStamp instanceof IntegerStamp && !((IntegerStamp) inputStamp).contains(0)) { 133 return StampFactory.objectNonNull(); 134 } else if (input.isConstant() && isZeroConstant(input)) { 135 return StampFactory.alwaysNull(); 136 } 137 return StampFactory.object(); 138 } 139 140 @Override 141 public boolean inferStamp() { 142 if (stamp instanceof AbstractPointerStamp) { 143 AbstractPointerStamp objectStamp = (AbstractPointerStamp) stamp; 144 if (!objectStamp.alwaysNull() && !objectStamp.nonNull()) { 145 Stamp newStamp = stamp; 146 Stamp inputStamp = input.stamp(NodeView.DEFAULT); 147 if (inputStamp instanceof AbstractPointerStamp) { 148 AbstractPointerStamp pointerStamp = (AbstractPointerStamp) inputStamp; 149 if (pointerStamp.alwaysNull()) { 150 newStamp = objectStamp.asAlwaysNull(); 151 } else if (pointerStamp.nonNull()) { 152 newStamp = objectStamp.asNonNull(); 153 } 154 } else if (inputStamp instanceof IntegerStamp && !((IntegerStamp) inputStamp).contains(0)) { 155 newStamp = objectStamp.asNonNull(); 156 } else if (input.isConstant() && isZeroConstant(input)) { 157 newStamp = objectStamp.asAlwaysNull(); 158 } 159 return updateStamp(newStamp); 160 } 161 } 162 return false; 163 } 164 165 @Override 166 public Node canonical(CanonicalizerTool tool) { 167 if (tool.allUsagesAvailable() && hasNoUsages()) { 168 /* If the cast is unused, it can be eliminated. */ 169 return input; 170 } 171 172 assert !stamp.isCompatible(input.stamp(NodeView.DEFAULT)); 173 if (input.isConstant()) { 174 /* Null pointers are uncritical for GC, so they can be constant folded. */ 175 if (input.asJavaConstant().isNull()) { 176 return ConstantNode.forIntegerStamp(stamp, 0); 177 } else if (isZeroConstant(input)) { 178 return ConstantNode.forConstant(stamp, ((AbstractPointerStamp) stamp).nullConstant(), tool.getMetaAccess()); 179 } 180 } 181 182 return this; 183 } 184 185 @Override 186 public void generate(NodeLIRBuilderTool generator) { 187 Value value = generator.operand(input); 188 ValueKind<?> kind = generator.getLIRGeneratorTool().getLIRKind(stamp(NodeView.DEFAULT)); 189 assert kind.getPlatformKind().getSizeInBytes() == value.getPlatformKind().getSizeInBytes(); 190 191 if (trackedPointer && LIRKind.isValue(kind) && !LIRKind.isValue(value)) { 192 // just change the PlatformKind, but don't drop reference information 193 kind = value.getValueKind().changeType(kind.getPlatformKind()); 194 } 195 196 if (kind.equals(value.getValueKind()) && !(value instanceof ConstantValue)) { 197 generator.setResult(this, value); 198 } else { 199 AllocatableValue result = generator.getLIRGeneratorTool().newVariable(kind); 200 if (stamp.equals(StampFactory.object())) { 201 generator.getLIRGeneratorTool().emitConvertZeroToNull(result, value); 202 } else if (!trackedPointer && !((AbstractPointerStamp) input.stamp(NodeView.DEFAULT)).nonNull()) { 203 generator.getLIRGeneratorTool().emitConvertNullToZero(result, value); 204 } else { 205 generator.getLIRGeneratorTool().emitMove(result, value); 206 } 207 generator.setResult(this, result); 208 } 209 } 210 }