FloatableAccessNode.java revision 12651:6ef01bd40ce2 
1/*
2 * Copyright (c) 2013, 2016, 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 */
23package org.graalvm.compiler.nodes.memory;
24
25import org.graalvm.compiler.core.common.LocationIdentity;
26import org.graalvm.compiler.core.common.type.Stamp;
27import org.graalvm.compiler.graph.NodeClass;
28import org.graalvm.compiler.nodeinfo.NodeInfo;
29import org.graalvm.compiler.nodes.FrameState;
30import org.graalvm.compiler.nodes.extended.GuardingNode;
31import org.graalvm.compiler.nodes.memory.address.AddressNode;
32
33/**
34 * An {@link FixedAccessNode} that can be converted to a {@link FloatingAccessNode}.
35 */
36@NodeInfo
37public abstract class FloatableAccessNode extends FixedAccessNode {
38    public static final NodeClass<FloatableAccessNode> TYPE = NodeClass.create(FloatableAccessNode.class);
39
40    protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp) {
41        super(c, address, location, stamp);
42    }
43
44    protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp, GuardingNode guard, BarrierType barrierType) {
45        super(c, address, location, stamp, guard, barrierType, false, null);
46    }
47
48    protected FloatableAccessNode(NodeClass<? extends FloatableAccessNode> c, AddressNode address, LocationIdentity location, Stamp stamp, GuardingNode guard, BarrierType barrierType,
49                    boolean nullCheck, FrameState stateBefore) {
50        super(c, address, location, stamp, guard, barrierType, nullCheck, stateBefore);
51    }
52
53    public abstract FloatingAccessNode asFloatingNode(MemoryNode lastLocationAccess);
54
55    protected boolean forceFixed;
56
57    public void setForceFixed(boolean flag) {
58        this.forceFixed = flag;
59    }
60
61    /**
62     * AccessNodes can float only if their location identities are not ANY_LOCATION. Furthermore, in
63     * case G1 is enabled any access (read) to the java.lang.ref.Reference.referent field which has
64     * an attached write barrier with pre-semantics can not also float.
65     */
66    public boolean canFloat() {
67        return !forceFixed && getLocationIdentity().isSingle() && getBarrierType() == BarrierType.NONE;
68    }
69}
70