001/*
002 * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.nodes.java;
024
025import jdk.internal.jvmci.meta.*;
026
027import com.oracle.graal.compiler.common.type.*;
028import com.oracle.graal.graph.*;
029import com.oracle.graal.nodeinfo.*;
030import com.oracle.graal.nodes.*;
031import com.oracle.graal.nodes.memory.*;
032import com.oracle.graal.nodes.memory.address.*;
033import com.oracle.graal.nodes.spi.*;
034
035/**
036 * Represents the lowered version of an atomic compare-and-swap operation{@code CompareAndSwapNode}.
037 */
038@NodeInfo(allowedUsageTypes = {InputType.Value, InputType.Memory})
039public final class LoweredCompareAndSwapNode extends FixedAccessNode implements StateSplit, LIRLowerable, MemoryCheckpoint.Single {
040
041    public static final NodeClass<LoweredCompareAndSwapNode> TYPE = NodeClass.create(LoweredCompareAndSwapNode.class);
042    @Input ValueNode expectedValue;
043    @Input ValueNode newValue;
044    @OptionalInput(InputType.State) FrameState stateAfter;
045
046    public FrameState stateAfter() {
047        return stateAfter;
048    }
049
050    public void setStateAfter(FrameState x) {
051        assert x == null || x.isAlive() : "frame state must be in a graph";
052        updateUsages(stateAfter, x);
053        stateAfter = x;
054    }
055
056    public boolean hasSideEffect() {
057        return true;
058    }
059
060    public ValueNode getExpectedValue() {
061        return expectedValue;
062    }
063
064    public ValueNode getNewValue() {
065        return newValue;
066    }
067
068    public LoweredCompareAndSwapNode(AddressNode address, LocationIdentity location, ValueNode expectedValue, ValueNode newValue, BarrierType barrierType) {
069        super(TYPE, address, location, StampFactory.forKind(Kind.Boolean.getStackKind()), barrierType);
070        assert expectedValue.getKind() == newValue.getKind();
071        this.expectedValue = expectedValue;
072        this.newValue = newValue;
073    }
074
075    public boolean canNullCheck() {
076        return false;
077    }
078
079    @Override
080    public void generate(NodeLIRBuilderTool gen) {
081        assert getNewValue().stamp().isCompatible(getExpectedValue().stamp());
082        Value result = gen.getLIRGeneratorTool().emitCompareAndSwap(gen.operand(getAddress()), gen.operand(getExpectedValue()), gen.operand(getNewValue()), JavaConstant.INT_1, JavaConstant.INT_0);
083        gen.setResult(this, result);
084    }
085}