GuardedValueNode.java revision 12657:6ef01bd40ce2 
1/*
2 * Copyright (c) 2013, 2015, 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;
24
25import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
26import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
27
28import org.graalvm.compiler.core.common.type.Stamp;
29import org.graalvm.compiler.graph.IterableNodeType;
30import org.graalvm.compiler.graph.Node;
31import org.graalvm.compiler.graph.NodeClass;
32import org.graalvm.compiler.graph.spi.Canonicalizable;
33import org.graalvm.compiler.graph.spi.CanonicalizerTool;
34import org.graalvm.compiler.nodeinfo.NodeInfo;
35import org.graalvm.compiler.nodes.extended.GuardingNode;
36import org.graalvm.compiler.nodes.spi.LIRLowerable;
37import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
38import org.graalvm.compiler.nodes.spi.ValueProxy;
39import org.graalvm.compiler.nodes.spi.Virtualizable;
40import org.graalvm.compiler.nodes.spi.VirtualizerTool;
41import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;
42
43import jdk.vm.ci.meta.JavaKind;
44
45/**
46 * A node that changes the type of its input, usually narrowing it. For example, a GuardedValueNode
47 * is used to keep the nodes depending on guards inside a loop during speculative guard movement.
48 *
49 * A GuardedValueNode will only go away if its guard is null or {@link StructuredGraph#start()}.
50 */
51@NodeInfo(cycles = CYCLES_0, size = SIZE_0)
52public final class GuardedValueNode extends FloatingGuardedNode implements LIRLowerable, Virtualizable, IterableNodeType, Canonicalizable, ValueProxy {
53
54    public static final NodeClass<GuardedValueNode> TYPE = NodeClass.create(GuardedValueNode.class);
55    @Input ValueNode object;
56    protected final Stamp piStamp;
57
58    public GuardedValueNode(ValueNode object, GuardingNode guard, Stamp stamp) {
59        super(TYPE, computeStamp(stamp, object), guard);
60        this.object = object;
61        this.piStamp = stamp;
62    }
63
64    public GuardedValueNode(ValueNode object, GuardingNode guard) {
65        this(object, guard, object.stamp());
66    }
67
68    public ValueNode object() {
69        return object;
70    }
71
72    @Override
73    public void generate(NodeLIRBuilderTool generator) {
74        if (object.getStackKind() != JavaKind.Void && object.getStackKind() != JavaKind.Illegal) {
75            generator.setResult(this, generator.operand(object));
76        }
77    }
78
79    @Override
80    public boolean inferStamp() {
81        return updateStamp(computeStamp(piStamp, object()));
82    }
83
84    static Stamp computeStamp(Stamp piStamp, ValueNode object) {
85        return piStamp.improveWith(object.stamp());
86    }
87
88    @Override
89    public void virtualize(VirtualizerTool tool) {
90        ValueNode alias = tool.getAlias(object());
91        if (alias instanceof VirtualObjectNode) {
92            tool.replaceWithVirtual((VirtualObjectNode) alias);
93        }
94    }
95
96    @Override
97    public Node canonical(CanonicalizerTool tool) {
98        if (getGuard() == null) {
99            if (stamp().equals(object().stamp())) {
100                return object();
101            } else {
102                return new PiNode(object(), stamp());
103            }
104        }
105        return this;
106    }
107
108    @Override
109    public ValueNode getOriginalNode() {
110        return object;
111    }
112}
113