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
24
25 package org.graalvm.compiler.nodes;
26
27 import java.util.function.Predicate;
28
29 import org.graalvm.compiler.core.common.type.Stamp;
30 import org.graalvm.compiler.graph.Node;
31 import org.graalvm.compiler.graph.NodeClass;
32 import org.graalvm.compiler.graph.iterators.NodePredicate;
33 import org.graalvm.compiler.nodeinfo.InputType;
34 import org.graalvm.compiler.nodeinfo.NodeInfo;
35 import org.graalvm.compiler.nodeinfo.Verbosity;
36 import org.graalvm.compiler.nodes.spi.NodeValueMap;
37
38 import jdk.vm.ci.meta.Constant;
39 import jdk.vm.ci.meta.JavaConstant;
40 import jdk.vm.ci.meta.JavaKind;
41
42 /**
43 * This class represents a value within the graph, including local variables, phis, and all other
44 * instructions.
45 */
46 @NodeInfo
47 public abstract class ValueNode extends org.graalvm.compiler.graph.Node implements ValueNodeInterface {
48
49 public static final NodeClass<ValueNode> TYPE = NodeClass.create(ValueNode.class);
50 /**
51 * The kind of this value. This is {@link JavaKind#Void} for instructions that produce no value.
52 * This kind is guaranteed to be a {@linkplain JavaKind#getStackKind() stack kind}.
53 */
54 protected Stamp stamp;
55
56 public ValueNode(NodeClass<? extends ValueNode> c, Stamp stamp) {
57 super(c);
58 this.stamp = stamp;
59 }
60
61 public final Stamp stamp(NodeView view) {
62 return view.stamp(this);
63 }
64
65 public final void setStamp(Stamp stamp) {
66 this.stamp = stamp;
67 assert !isAlive() || !inferStamp() : "setStamp called on a node that overrides inferStamp: " + this;
68 }
69
70 @Override
71 public final StructuredGraph graph() {
72 return (StructuredGraph) super.graph();
73 }
74
75 /**
76 * Checks if the given stamp is different than the current one (
77 * {@code newStamp.equals(oldStamp) == false}). If it is different then the new stamp will
78 * become the current stamp for this node.
79 *
80 * @return true if the stamp has changed, false otherwise.
81 */
82 protected final boolean updateStamp(Stamp newStamp) {
83 if (newStamp == null || newStamp.equals(stamp)) {
84 return false;
85 } else {
86 stamp = newStamp;
87 return true;
88 }
89 }
90
91 /**
92 * This method can be overridden by subclasses of {@link ValueNode} if they need to recompute
93 * their stamp if their inputs change. A typical implementation will compute the stamp and pass
94 * it to {@link #updateStamp(Stamp)}, whose return value can be used as the result of this
95 * method.
96 *
97 * @return true if the stamp has changed, false otherwise.
98 */
99 public boolean inferStamp() {
100 return false;
101 }
102
103 public final JavaKind getStackKind() {
104 return stamp(NodeView.DEFAULT).getStackKind();
105 }
106
107 /**
108 * Checks whether this value is a constant (i.e. it is of type {@link ConstantNode}.
109 *
110 * @return {@code true} if this value is a constant
111 */
112 public final boolean isConstant() {
113 return this instanceof ConstantNode;
114 }
115
116 private static final NodePredicate IS_CONSTANT = new NodePredicate() {
117 @Override
118 public boolean apply(Node n) {
119 return n instanceof ConstantNode;
120 }
121 };
122
123 public static NodePredicate isConstantPredicate() {
124 return IS_CONSTANT;
125 }
126
127 /**
128 * Checks whether this value represents the null constant.
129 *
130 * @return {@code true} if this value represents the null constant
131 */
132 public final boolean isNullConstant() {
133 JavaConstant value = asJavaConstant();
134 return value != null && value.isNull();
135 }
136
137 public final boolean isDefaultConstant() {
138 Constant value = asConstant();
139 return value != null && value.isDefaultForKind();
140 }
141
142 /**
143 * Convert this value to a constant if it is a constant, otherwise return null.
144 *
145 * @return the {@link JavaConstant} represented by this value if it is a constant; {@code null}
146 * otherwise
147 */
148 public final Constant asConstant() {
149 if (this instanceof ConstantNode) {
150 return ((ConstantNode) this).getValue();
151 } else {
152 return null;
153 }
154 }
155
156 public final boolean isJavaConstant() {
157 return isConstant() && asConstant() instanceof JavaConstant;
158 }
159
160 public final JavaConstant asJavaConstant() {
161 Constant value = asConstant();
162 if (value instanceof JavaConstant) {
163 return (JavaConstant) value;
164 } else {
165 return null;
166 }
167 }
168
169 @Override
170 public ValueNode asNode() {
171 return this;
172 }
173
174 @Override
175 public boolean isAllowedUsageType(InputType type) {
176 if (getStackKind() != JavaKind.Void && type == InputType.Value) {
177 return true;
178 } else {
179 return super.isAllowedUsageType(type);
180 }
181 }
182
183 /**
184 * Checks if this node has usages other than the given node {@code node}.
185 *
186 * @param node node which is ignored when searching for usages
187 * @param nodeValueMap
188 * @return true if this node has other usages, false otherwise
189 */
190 public boolean hasUsagesOtherThan(ValueNode node, NodeValueMap nodeValueMap) {
191 for (Node usage : usages()) {
192 if (usage != node && usage instanceof ValueNode && nodeValueMap.hasOperand(usage)) {
193 return true;
194 }
195 }
196 return false;
197 }
198
199 @Override
200 protected void replaceAtUsages(Node other, Predicate<Node> filter, Node toBeDeleted) {
201 super.replaceAtUsages(other, filter, toBeDeleted);
202 assert checkReplaceAtUsagesInvariants(other);
203 }
204
205 private boolean checkReplaceAtUsagesInvariants(Node other) {
206 assert other == null || other instanceof ValueNode;
207 if (this.hasUsages() && !this.stamp(NodeView.DEFAULT).isEmpty() && !(other instanceof PhiNode) && other != null) {
208 assert ((ValueNode) other).stamp(NodeView.DEFAULT).getClass() == stamp(NodeView.DEFAULT).getClass() : "stamp have to be of same class";
209 boolean morePrecise = ((ValueNode) other).stamp(NodeView.DEFAULT).join(stamp(NodeView.DEFAULT)).equals(((ValueNode) other).stamp(NodeView.DEFAULT));
210 assert morePrecise : "stamp can only get more precise " + toString(Verbosity.All) + " " +
211 other.toString(Verbosity.All);
212 }
213 return true;
214 }
215 }