1 /*
   2  * Copyright (c) 2011, 2018, 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.nodes.java;
  26 
  27 import org.graalvm.compiler.core.common.type.StampFactory;
  28 import org.graalvm.compiler.graph.NodeClass;
  29 import org.graalvm.compiler.nodeinfo.NodeInfo;
  30 import org.graalvm.compiler.nodes.ConstantNode;
  31 import org.graalvm.compiler.nodes.LogicNode;
  32 import org.graalvm.compiler.nodes.NodeView;
  33 import org.graalvm.compiler.nodes.ValueNode;
  34 import org.graalvm.compiler.nodes.calc.ConditionalNode;
  35 import org.graalvm.compiler.nodes.spi.VirtualizerTool;
  36 import jdk.internal.vm.compiler.word.LocationIdentity;
  37 
  38 import jdk.vm.ci.meta.JavaKind;
  39 
  40 /**
  41  * Represents an atomic compare-and-swap operation. The result is a boolean that contains whether
  42  * the value matched the expected value.
  43  */
  44 @NodeInfo
  45 public final class UnsafeCompareAndSwapNode extends AbstractUnsafeCompareAndSwapNode {
  46 
  47     public static final NodeClass<UnsafeCompareAndSwapNode> TYPE = NodeClass.create(UnsafeCompareAndSwapNode.class);
  48 
  49     public UnsafeCompareAndSwapNode(ValueNode object, ValueNode offset, ValueNode expected, ValueNode newValue, JavaKind valueKind, LocationIdentity locationIdentity) {
  50         super(TYPE, StampFactory.forKind(JavaKind.Boolean.getStackKind()), object, offset, expected, newValue, valueKind, locationIdentity);
  51         assert expected.stamp(NodeView.DEFAULT).isCompatible(newValue.stamp(NodeView.DEFAULT));
  52     }
  53 
  54     @Override
  55     protected void finishVirtualize(VirtualizerTool tool, LogicNode equalsNode, ValueNode currentValue) {
  56         ValueNode result = ConditionalNode.create(equalsNode, ConstantNode.forBoolean(true, graph()), ConstantNode.forBoolean(false, graph()), NodeView.DEFAULT);
  57         if (!result.isAlive()) {
  58             tool.addNode(result);
  59         }
  60         tool.replaceWith(result);
  61     }
  62 }