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.hotspot.nodes;
024
025import com.oracle.graal.graph.*;
026import com.oracle.graal.nodeinfo.*;
027import com.oracle.graal.nodes.*;
028import com.oracle.graal.nodes.memory.address.*;
029
030/**
031 * The {@code G1ReferentFieldReadBarrier} is added when a read access is performed to the referent
032 * field of a {@link java.lang.ref.Reference} object (through a {@code LoadFieldNode} or an
033 * {@code UnsafeLoadNode}). The return value of the read is passed to the snippet implementing the
034 * read barrier and consequently is added to the SATB queue if the concurrent marker is enabled.
035 */
036@NodeInfo
037public final class G1ReferentFieldReadBarrier extends ObjectWriteBarrier {
038    public static final NodeClass<G1ReferentFieldReadBarrier> TYPE = NodeClass.create(G1ReferentFieldReadBarrier.class);
039
040    protected final boolean doLoad;
041
042    public G1ReferentFieldReadBarrier(AddressNode address, ValueNode expectedObject, boolean doLoad) {
043        super(TYPE, address, expectedObject, true);
044        this.doLoad = doLoad;
045    }
046
047    public ValueNode getExpectedObject() {
048        return getValue();
049    }
050
051    public boolean doLoad() {
052        return doLoad;
053    }
054}