/* * Copyright (c) 2013, 2015, 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.word; import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1; import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1; import org.graalvm.compiler.core.common.LIRKind; import org.graalvm.compiler.core.common.type.AbstractPointerStamp; import org.graalvm.compiler.core.common.type.IntegerStamp; import org.graalvm.compiler.core.common.type.ObjectStamp; import org.graalvm.compiler.core.common.type.Stamp; import org.graalvm.compiler.core.common.type.StampFactory; import org.graalvm.compiler.graph.Node; import org.graalvm.compiler.graph.NodeClass; import org.graalvm.compiler.graph.spi.Canonicalizable; import org.graalvm.compiler.graph.spi.CanonicalizerTool; import org.graalvm.compiler.lir.ConstantValue; import org.graalvm.compiler.nodeinfo.NodeInfo; import org.graalvm.compiler.nodes.ConstantNode; import org.graalvm.compiler.nodes.FixedWithNextNode; import org.graalvm.compiler.nodes.NodeView; import org.graalvm.compiler.nodes.ValueNode; import org.graalvm.compiler.nodes.spi.LIRLowerable; import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool; import org.graalvm.compiler.nodes.type.NarrowOopStamp; import jdk.vm.ci.meta.AllocatableValue; import jdk.vm.ci.meta.JavaConstant; import jdk.vm.ci.meta.JavaKind; import jdk.vm.ci.meta.Value; import jdk.vm.ci.meta.ValueKind; /** * Casts between Word and Object exposed by the {@link Word#fromAddress}, * {@link Word#objectToTrackedPointer}, {@link Word#objectToUntrackedPointer} and * {@link Word#toObject()} operations. It has an impact on the pointer maps for the GC, so it must * not be scheduled or optimized away. */ @NodeInfo(cycles = CYCLES_1, size = SIZE_1) public final class WordCastNode extends FixedWithNextNode implements LIRLowerable, Canonicalizable { public static final NodeClass TYPE = NodeClass.create(WordCastNode.class); @Input ValueNode input; private final boolean trackedPointer; public static WordCastNode wordToObject(ValueNode input, JavaKind wordKind) { assert input.getStackKind() == wordKind; return new WordCastNode(objectStampFor(input), input); } public static WordCastNode wordToObjectNonNull(ValueNode input, JavaKind wordKind) { assert input.getStackKind() == wordKind; return new WordCastNode(StampFactory.objectNonNull(), input); } public static WordCastNode wordToNarrowObject(ValueNode input, NarrowOopStamp stamp) { return new WordCastNode(stamp, input); } public static WordCastNode addressToWord(ValueNode input, JavaKind wordKind) { assert input.stamp(NodeView.DEFAULT) instanceof AbstractPointerStamp; return new WordCastNode(StampFactory.forKind(wordKind), input); } public static WordCastNode objectToTrackedPointer(ValueNode input, JavaKind wordKind) { assert input.stamp(NodeView.DEFAULT) instanceof ObjectStamp; return new WordCastNode(StampFactory.forKind(wordKind), input); } public static WordCastNode objectToUntrackedPointer(ValueNode input, JavaKind wordKind) { assert input.stamp(NodeView.DEFAULT) instanceof ObjectStamp; return new WordCastNode(StampFactory.forKind(wordKind), input, false); } public static WordCastNode narrowOopToUntrackedWord(ValueNode input, JavaKind wordKind) { assert input.stamp(NodeView.DEFAULT) instanceof NarrowOopStamp; return new WordCastNode(StampFactory.forKind(wordKind), input, false); } private WordCastNode(Stamp stamp, ValueNode input) { this(stamp, input, true); } protected WordCastNode(Stamp stamp, ValueNode input, boolean trackedPointer) { super(TYPE, stamp); this.input = input; this.trackedPointer = trackedPointer; } public ValueNode getInput() { return input; } private static boolean isZeroConstant(ValueNode value) { JavaConstant constant = value.asJavaConstant(); return constant.getJavaKind().isNumericInteger() && constant.asLong() == 0; } private static Stamp objectStampFor(ValueNode input) { Stamp inputStamp = input.stamp(NodeView.DEFAULT); if (inputStamp instanceof AbstractPointerStamp) { AbstractPointerStamp pointerStamp = (AbstractPointerStamp) inputStamp; if (pointerStamp.alwaysNull()) { return StampFactory.alwaysNull(); } else if (pointerStamp.nonNull()) { return StampFactory.objectNonNull(); } } else if (inputStamp instanceof IntegerStamp && !((IntegerStamp) inputStamp).contains(0)) { return StampFactory.objectNonNull(); } else if (input.isConstant() && isZeroConstant(input)) { return StampFactory.alwaysNull(); } return StampFactory.object(); } @Override public boolean inferStamp() { if (stamp instanceof AbstractPointerStamp) { AbstractPointerStamp objectStamp = (AbstractPointerStamp) stamp; if (!objectStamp.alwaysNull() && !objectStamp.nonNull()) { Stamp newStamp = stamp; Stamp inputStamp = input.stamp(NodeView.DEFAULT); if (inputStamp instanceof AbstractPointerStamp) { AbstractPointerStamp pointerStamp = (AbstractPointerStamp) inputStamp; if (pointerStamp.alwaysNull()) { newStamp = objectStamp.asAlwaysNull(); } else if (pointerStamp.nonNull()) { newStamp = objectStamp.asNonNull(); } } else if (inputStamp instanceof IntegerStamp && !((IntegerStamp) inputStamp).contains(0)) { newStamp = objectStamp.asNonNull(); } else if (input.isConstant() && isZeroConstant(input)) { newStamp = objectStamp.asAlwaysNull(); } return updateStamp(newStamp); } } return false; } @Override public Node canonical(CanonicalizerTool tool) { if (tool.allUsagesAvailable() && hasNoUsages()) { /* If the cast is unused, it can be eliminated. */ return input; } assert !stamp.isCompatible(input.stamp(NodeView.DEFAULT)); if (input.isConstant()) { /* Null pointers are uncritical for GC, so they can be constant folded. */ if (input.asJavaConstant().isNull()) { return ConstantNode.forIntegerStamp(stamp, 0); } else if (isZeroConstant(input)) { return ConstantNode.forConstant(stamp, ((AbstractPointerStamp) stamp).nullConstant(), tool.getMetaAccess()); } } return this; } @Override public void generate(NodeLIRBuilderTool generator) { Value value = generator.operand(input); ValueKind kind = generator.getLIRGeneratorTool().getLIRKind(stamp(NodeView.DEFAULT)); assert kind.getPlatformKind().getSizeInBytes() == value.getPlatformKind().getSizeInBytes(); if (trackedPointer && LIRKind.isValue(kind) && !LIRKind.isValue(value)) { // just change the PlatformKind, but don't drop reference information kind = value.getValueKind().changeType(kind.getPlatformKind()); } if (kind.equals(value.getValueKind()) && !(value instanceof ConstantValue)) { generator.setResult(this, value); } else { AllocatableValue result = generator.getLIRGeneratorTool().newVariable(kind); if (stamp.equals(StampFactory.object())) { generator.getLIRGeneratorTool().emitConvertZeroToNull(result, value); } else if (!trackedPointer && !((AbstractPointerStamp) input.stamp(NodeView.DEFAULT)).nonNull()) { generator.getLIRGeneratorTool().emitConvertNullToZero(result, value); } else { generator.getLIRGeneratorTool().emitMove(result, value); } generator.setResult(this, result); } } }