1 /*
2 * Copyright (c) 2009, 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 */
23 package org.graalvm.compiler.nodes;
24
25 import org.graalvm.compiler.core.common.type.Stamp;
26 import org.graalvm.compiler.graph.Node;
27 import org.graalvm.compiler.graph.NodeClass;
28 import org.graalvm.compiler.graph.iterators.NodePredicate;
29 import org.graalvm.compiler.nodeinfo.InputType;
30 import org.graalvm.compiler.nodeinfo.NodeInfo;
31 import org.graalvm.compiler.nodes.spi.NodeValueMap;
32
33 import jdk.vm.ci.meta.Constant;
34 import jdk.vm.ci.meta.JavaConstant;
35 import jdk.vm.ci.meta.JavaKind;
36
37 /**
38 * This class represents a value within the graph, including local variables, phis, and all other
39 * instructions.
40 */
41 @NodeInfo
42 public abstract class ValueNode extends org.graalvm.compiler.graph.Node implements ValueNodeInterface {
43
44 public static final NodeClass<ValueNode> TYPE = NodeClass.create(ValueNode.class);
45 /**
46 * The kind of this value. This is {@link JavaKind#Void} for instructions that produce no value.
47 * This kind is guaranteed to be a {@linkplain JavaKind#getStackKind() stack kind}.
48 */
49 protected Stamp stamp;
50
51 public ValueNode(NodeClass<? extends ValueNode> c, Stamp stamp) {
52 super(c);
53 this.stamp = stamp;
54 }
55
56 public final Stamp stamp() {
57 return stamp;
58 }
59
60 public final void setStamp(Stamp stamp) {
61 this.stamp = stamp;
62 assert !isAlive() || !inferStamp() : "setStamp called on a node that overrides inferStamp: " + this;
63 }
64
65 @Override
66 public final StructuredGraph graph() {
67 return (StructuredGraph) super.graph();
68 }
69
70 /**
71 * Checks if the given stamp is different than the current one (
72 * {@code newStamp.equals(oldStamp) == false}). If it is different then the new stamp will
73 * become the current stamp for this node.
74 *
75 * @return true if the stamp has changed, false otherwise.
76 */
77 protected final boolean updateStamp(Stamp newStamp) {
78 if (newStamp == null || newStamp.equals(stamp)) {
79 return false;
80 } else {
81 stamp = newStamp;
82 return true;
83 }
84 }
85
86 /**
87 * This method can be overridden by subclasses of {@link ValueNode} if they need to recompute
88 * their stamp if their inputs change. A typical implementation will compute the stamp and pass
89 * it to {@link #updateStamp(Stamp)}, whose return value can be used as the result of this
90 * method.
91 *
92 * @return true if the stamp has changed, false otherwise.
93 */
94 public boolean inferStamp() {
95 return false;
96 }
97
98 public final JavaKind getStackKind() {
99 return stamp().getStackKind();
100 }
101
102 /**
103 * Checks whether this value is a constant (i.e. it is of type {@link ConstantNode}.
104 *
105 * @return {@code true} if this value is a constant
106 */
107 public final boolean isConstant() {
108 return this instanceof ConstantNode;
109 }
110
111 private static final NodePredicate IS_CONSTANT = new NodePredicate() {
112 @Override
113 public boolean apply(Node n) {
114 return n instanceof ConstantNode;
115 }
116 };
117
118 public static NodePredicate isConstantPredicate() {
119 return IS_CONSTANT;
120 }
121
122 /**
123 * Checks whether this value represents the null constant.
124 *
125 * @return {@code true} if this value represents the null constant
126 */
127 public final boolean isNullConstant() {
128 JavaConstant value = asJavaConstant();
129 return value != null && value.isNull();
130 }
131
132 /**
133 * Convert this value to a constant if it is a constant, otherwise return null.
134 *
135 * @return the {@link JavaConstant} represented by this value if it is a constant; {@code null}
136 * otherwise
137 */
138 public final Constant asConstant() {
139 if (this instanceof ConstantNode) {
140 return ((ConstantNode) this).getValue();
141 } else {
142 return null;
143 }
144 }
145
146 public final JavaConstant asJavaConstant() {
147 Constant value = asConstant();
148 if (value instanceof JavaConstant) {
149 return (JavaConstant) value;
150 } else {
151 return null;
152 }
153 }
154
155 @Override
156 public ValueNode asNode() {
157 return this;
158 }
159
160 @Override
161 public boolean isAllowedUsageType(InputType type) {
162 if (getStackKind() != JavaKind.Void && type == InputType.Value) {
163 return true;
164 } else {
165 return super.isAllowedUsageType(type);
166 }
167 }
168
169 /**
170 * Checks if this node has usages other than the given node {@code node}.
171 *
172 * @param node node which is ignored when searching for usages
173 * @param nodeValueMap
174 * @return true if this node has other usages, false otherwise
175 */
176 public boolean hasUsagesOtherThan(ValueNode node, NodeValueMap nodeValueMap) {
177 for (Node usage : usages()) {
178 if (usage != node && usage instanceof ValueNode && nodeValueMap.hasOperand(usage)) {
179 return true;
180 }
181 }
182 return false;
183 }
184
185 }