Mercurial > hg > graal-compiler
view graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/java/AccessMonitorNode.java @ 5362:d42425beb1d1
pulled AbstractStateSplit into FixedWithNextNode and made it no longer implement StateSplit. StateSplit is now implemented only by nodes that really have side effects.
author | Doug Simon <doug.simon@oracle.com> |
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date | Tue, 08 May 2012 15:52:01 +0200 |
parents | 0ebd9cfdc11f |
children | 3035b6b881d9 |
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/* * Copyright (c) 2009, 2012, 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 com.oracle.graal.nodes.java; import com.oracle.max.cri.ci.*; import com.oracle.graal.nodes.*; import com.oracle.graal.nodes.extended.*; import com.oracle.graal.nodes.type.*; /** * The {@code AccessMonitorNode} is the base class of both monitor acquisition and release. * <br> * The VM needs information about monitors in the debug information. This information is built from * the nesting level of {@link MonitorEnterNode} when the LIR is constructed. Therefore, monitor * nodes must not be removed from the graph unless it is guaranteed that the nesting level does not change. * For example, you must not remove a {@link MonitorEnterNode} for a thread-local object or for a recursive locking. * Instead, mark the node as {@link #eliminated}. This makes sure that the meta data still contains the complete * locking hierarchy. * <br> * The Java bytecode specification allows non-balanced locking. Graal does not handle such cases and throws a * {@link CiBailout} instead. Detecting non-balanced monitors during bytecode parsing is difficult, since the * node flowing into the {@link MonitorExitNode} can be a phi function hiding the node that was flowing into the * {@link MonitorEnterNode}. Optimization phases are free to throw {@link CiBailout} if they detect such cases. * Otherwise, they are detected during LIR construction. */ public abstract class AccessMonitorNode extends FixedWithNextNode implements StateSplit, MemoryCheckpoint { @Input private ValueNode object; private boolean eliminated; public ValueNode object() { return object; } public boolean eliminated() { return eliminated; } public void eliminate() { eliminated = true; } /** * Creates a new AccessMonitor instruction. * * @param object the instruction producing the object */ public AccessMonitorNode(ValueNode object) { super(StampFactory.illegal()); this.object = object; } }