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  */
23 
24 
25 package org.graalvm.compiler.nodes;
26 
27 import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
28 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
29 
30 import org.graalvm.compiler.graph.Node;
31 import org.graalvm.compiler.graph.NodeClass;
32 import org.graalvm.compiler.graph.spi.Canonicalizable;
33 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
34 import org.graalvm.compiler.nodeinfo.NodeInfo;
35 import org.graalvm.compiler.nodes.extended.GuardingNode;
36 import org.graalvm.compiler.nodes.spi.LIRLowerable;
37 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
38 import org.graalvm.compiler.nodes.spi.ValueProxy;
39 import org.graalvm.compiler.nodes.spi.Virtualizable;
40 import org.graalvm.compiler.nodes.spi.VirtualizerTool;
41 import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;
42 
43 import 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)
52 public final class GuardedValueNode extends FloatingGuardedNode implements LIRLowerable, Virtualizable, Canonicalizable, ValueProxy {
53 
54     public static final NodeClass<GuardedValueNode> TYPE = NodeClass.create(GuardedValueNode.class);
55     @Input ValueNode object;
56 
GuardedValueNode(ValueNode object, GuardingNode guard)57     public GuardedValueNode(ValueNode object, GuardingNode guard) {
58         super(TYPE, object.stamp(NodeView.DEFAULT), guard);
59         this.object = object;
60     }
61 
object()62     public ValueNode object() {
63         return object;
64     }
65 
66     @Override
generate(NodeLIRBuilderTool generator)67     public void generate(NodeLIRBuilderTool generator) {
68         if (object.getStackKind() != JavaKind.Void && object.getStackKind() != JavaKind.Illegal) {
69             generator.setResult(this, generator.operand(object));
70         }
71     }
72 
73     @Override
inferStamp()74     public boolean inferStamp() {
75         return updateStamp(object().stamp(NodeView.DEFAULT));
76     }
77 
78     @Override
virtualize(VirtualizerTool tool)79     public void virtualize(VirtualizerTool tool) {
80         ValueNode alias = tool.getAlias(object());
81         if (alias instanceof VirtualObjectNode) {
82             tool.replaceWithVirtual((VirtualObjectNode) alias);
83         }
84     }
85 
86     @Override
canonical(CanonicalizerTool tool)87     public Node canonical(CanonicalizerTool tool) {
88         if (getGuard() == null) {
89             if (stamp(NodeView.DEFAULT).equals(object().stamp(NodeView.DEFAULT))) {
90                 return object();
91             } else {
92                 return PiNode.create(object(), stamp(NodeView.DEFAULT));
93             }
94         }
95         return this;
96     }
97 
98     @Override
getOriginalNode()99     public ValueNode getOriginalNode() {
100         return object;
101     }
102 }
103