1 /*
2 * Copyright (c) 2012, 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 static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_0;
26 import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_0;
27
28 import jdk.vm.ci.meta.JavaKind;
29 import jdk.vm.ci.meta.ResolvedJavaMethod;
30 import org.graalvm.compiler.core.common.type.AbstractPointerStamp;
31 import org.graalvm.compiler.core.common.type.ObjectStamp;
32 import org.graalvm.compiler.core.common.type.Stamp;
33 import org.graalvm.compiler.core.common.type.StampFactory;
34 import org.graalvm.compiler.core.common.type.TypeReference;
35 import org.graalvm.compiler.graph.IterableNodeType;
36 import org.graalvm.compiler.graph.Node;
37 import org.graalvm.compiler.graph.NodeClass;
38 import org.graalvm.compiler.graph.spi.Canonicalizable;
39 import org.graalvm.compiler.graph.spi.CanonicalizerTool;
40 import org.graalvm.compiler.nodeinfo.NodeInfo;
41 import org.graalvm.compiler.nodes.extended.GuardingNode;
42 import org.graalvm.compiler.nodes.graphbuilderconf.GraphBuilderContext;
43 import org.graalvm.compiler.nodes.memory.ReadNode;
44 import org.graalvm.compiler.nodes.spi.LIRLowerable;
45 import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
46 import org.graalvm.compiler.nodes.spi.ValueProxy;
47 import org.graalvm.compiler.nodes.spi.Virtualizable;
48 import org.graalvm.compiler.nodes.spi.VirtualizerTool;
49 import org.graalvm.compiler.nodes.type.StampTool;
50 import org.graalvm.compiler.nodes.virtual.VirtualObjectNode;
51
52 //JaCoCo Exclude
53
54 import jdk.vm.ci.meta.ResolvedJavaType;
55
56 /**
57 * A node that changes the type of its input, usually narrowing it. For example, a {@link PiNode}
58 * refines the type of a receiver during type-guarded inlining to be the type tested by the guard.
59 *
60 * In contrast to a {@link GuardedValueNode}, a {@link PiNode} is useless as soon as the type of its
61 * input is as narrow or narrower than the {@link PiNode}'s type. The {@link PiNode}, and therefore
62 * also the scheduling restriction enforced by the guard, will go away.
63 */
64 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
65 public class PiNode extends FloatingGuardedNode implements LIRLowerable, Virtualizable, IterableNodeType, Canonicalizable, ValueProxy {
66
67 public static final NodeClass<PiNode> TYPE = NodeClass.create(PiNode.class);
68 @Input ValueNode object;
69 protected Stamp piStamp;
70
71 public ValueNode object() {
72 return object;
73 }
74
75 protected PiNode(NodeClass<? extends PiNode> c, ValueNode object, Stamp stamp, GuardingNode guard) {
76 super(c, stamp, guard);
77 this.object = object;
78 this.piStamp = stamp;
79 assert piStamp.isCompatible(object.stamp()) : "Object stamp not compatible to piStamp";
80 inferStamp();
81 }
82
83 public PiNode(ValueNode object, Stamp stamp) {
84 this(object, stamp, null);
85 }
86
87 public PiNode(ValueNode object, Stamp stamp, ValueNode guard) {
88 this(TYPE, object, stamp, (GuardingNode) guard);
89 }
90
91 public PiNode(ValueNode object, ValueNode guard) {
92 this(object, AbstractPointerStamp.pointerNonNull(object.stamp()), guard);
93 }
94
95 public PiNode(ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
96 this(object, StampFactory.object(exactType ? TypeReference.createExactTrusted(toType) : TypeReference.createWithoutAssumptions(toType), nonNull || StampTool.isPointerNonNull(object.stamp())));
97 }
98
99 public static ValueNode create(ValueNode object, Stamp stamp) {
100 ValueNode value = canonical(object, stamp, null);
101 if (value != null) {
102 return value;
103 }
104 return new PiNode(object, stamp);
105 }
106
107 public static ValueNode create(ValueNode object, Stamp stamp, ValueNode guard) {
108 ValueNode value = canonical(object, stamp, (GuardingNode) guard);
109 if (value != null) {
110 return value;
111 }
112 return new PiNode(object, stamp, guard);
113 }
114
115 public static ValueNode create(ValueNode object, ValueNode guard) {
116 Stamp stamp = AbstractPointerStamp.pointerNonNull(object.stamp());
117 ValueNode value = canonical(object, stamp, (GuardingNode) guard);
118 if (value != null) {
119 return value;
120 }
121 return new PiNode(object, stamp, guard);
122 }
123
124 @SuppressWarnings("unused")
125 public static boolean intrinsify(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode object, ValueNode guard) {
126 Stamp stamp = AbstractPointerStamp.pointerNonNull(object.stamp());
127 ValueNode value = canonical(object, stamp, (GuardingNode) guard);
128 if (value == null) {
129 value = new PiNode(object, stamp, guard);
130 }
131 b.push(JavaKind.Object, b.append(value));
132 return true;
133 }
134
135 @SuppressWarnings("unused")
136 public static boolean intrinsify(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
137 Stamp stamp = StampFactory.object(exactType ? TypeReference.createExactTrusted(toType) : TypeReference.createWithoutAssumptions(toType), nonNull || StampTool.isPointerNonNull(object.stamp()));
138 ValueNode value = canonical(object, stamp, null);
139 if (value == null) {
140 value = new PiNode(object, stamp);
141 }
142 b.push(JavaKind.Object, b.append(value));
143 return true;
144 }
145
146 public final Stamp piStamp() {
147 return piStamp;
148 }
149
150 public void strengthenPiStamp(Stamp newPiStamp) {
151 assert this.piStamp.join(newPiStamp).equals(newPiStamp) : "stamp can only improve";
152 this.piStamp = newPiStamp;
153 }
154
155 @Override
156 public void generate(NodeLIRBuilderTool generator) {
157 if (generator.hasOperand(object)) {
158 generator.setResult(this, generator.operand(object));
159 }
160 }
161
162 @Override
163 public boolean inferStamp() {
164 return updateStamp(computeStamp());
165 }
166
167 private Stamp computeStamp() {
168 return piStamp.improveWith(object().stamp());
169 }
170
171 @Override
172 public void virtualize(VirtualizerTool tool) {
173 ValueNode alias = tool.getAlias(object());
174 if (alias instanceof VirtualObjectNode) {
175 VirtualObjectNode virtual = (VirtualObjectNode) alias;
176 if (StampTool.typeOrNull(this) != null && StampTool.typeOrNull(this).isAssignableFrom(virtual.type())) {
177 tool.replaceWithVirtual(virtual);
178 }
179 }
180 }
181
182 public static ValueNode canonical(ValueNode object, Stamp stamp, GuardingNode guard) {
183 // Use most up to date stamp.
184 Stamp computedStamp = stamp.improveWith(object.stamp());
185
186 // The pi node does not give any additional information => skip it.
187 if (computedStamp.equals(object.stamp())) {
188 return object;
189 }
190
191 if (guard == null) {
192 // Try to merge the pi node with a load node.
193 if (object instanceof ReadNode) {
194 ReadNode readNode = (ReadNode) object;
195 readNode.setStamp(readNode.stamp().improveWith(stamp));
196 return readNode;
197 }
198 } else {
199 for (Node n : guard.asNode().usages()) {
200 if (n instanceof PiNode) {
201 PiNode otherPi = (PiNode) n;
202 if (object == otherPi.object() && computedStamp.equals(otherPi.stamp())) {
203 /*
204 * Two PiNodes with the same guard and same result, so return the one with
205 * the more precise piStamp.
206 */
207 Stamp newStamp = stamp.join(otherPi.piStamp);
208 if (newStamp.equals(otherPi.piStamp)) {
209 return otherPi;
210 }
211 }
212 }
213 }
214 }
215 return null;
216 }
217
218 @Override
219 public Node canonical(CanonicalizerTool tool) {
220 Node value = canonical(object(), stamp(), getGuard());
221 if (value != null) {
222 return value;
223 }
224 return this;
225 }
226
227 @Override
228 public ValueNode getOriginalNode() {
229 return object;
230 }
231
232 public void setOriginalNode(ValueNode newNode) {
233 this.updateUsages(object, newNode);
234 this.object = newNode;
235 assert piStamp.isCompatible(object.stamp()) : "New object stamp not compatible to piStamp";
236 }
237
238 /**
239 * Casts an object to have an exact, non-null stamp representing {@link Class}.
240 */
241 public static Class<?> asNonNullClass(Object object) {
242 return asNonNullClassIntrinsic(object, Class.class, true, true);
243 }
244
245 /**
246 * Casts an object to have an exact, non-null stamp representing {@link Class}.
247 */
248 public static Class<?> asNonNullObject(Object object) {
249 return asNonNullClassIntrinsic(object, Object.class, false, true);
250 }
251
252 @NodeIntrinsic(PiNode.class)
253 private static native Class<?> asNonNullClassIntrinsic(Object object, @ConstantNodeParameter Class<?> toType, @ConstantNodeParameter boolean exactType, @ConstantNodeParameter boolean nonNull);
254
255 /**
256 * Changes the stamp of an object inside a snippet to be the stamp of the node replaced by the
257 * snippet.
258 */
259 @NodeIntrinsic(PiNode.Placeholder.class)
260 public static native Object piCastToSnippetReplaceeStamp(Object object);
261
262 /**
263 * Changes the stamp of an object and ensures the newly stamped value is non-null and does not
264 * float above a given guard.
265 */
266 @NodeIntrinsic
267 public static native Object piCastNonNull(Object object, GuardingNode guard);
268
269 /**
270 * Changes the stamp of an object and ensures the newly stamped value is non-null and does not
271 * float above a given guard.
272 */
273 @NodeIntrinsic
274 public static native Class<?> piCastNonNullClass(Class<?> type, GuardingNode guard);
275
276 /**
277 * Changes the stamp of an object to represent a given type and to indicate that the object is
278 * not null.
279 */
280 public static Object piCastNonNull(Object object, @ConstantNodeParameter Class<?> toType) {
281 return piCast(object, toType, false, true);
282 }
283
284 @NodeIntrinsic
285 public static native Object piCast(Object object, @ConstantNodeParameter Class<?> toType, @ConstantNodeParameter boolean exactType, @ConstantNodeParameter boolean nonNull);
286
287 /**
288 * A placeholder node in a snippet that will be replaced with a {@link PiNode} when the snippet
289 * is instantiated.
290 */
291 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
292 public static class Placeholder extends FloatingGuardedNode {
293
294 public static final NodeClass<Placeholder> TYPE = NodeClass.create(Placeholder.class);
295 @Input ValueNode object;
296
297 public ValueNode object() {
298 return object;
299 }
300
301 protected Placeholder(NodeClass<? extends Placeholder> c, ValueNode object) {
302 super(c, PlaceholderStamp.SINGLETON, null);
303 this.object = object;
304 }
305
306 public Placeholder(ValueNode object) {
307 this(TYPE, object);
308 }
309
310 /**
311 * Replaces this node with a {@link PiNode} during snippet instantiation.
312 *
313 * @param snippetReplaceeStamp the stamp of the node being replace by the snippet
314 */
315 public void makeReplacement(Stamp snippetReplaceeStamp) {
316 ValueNode value = graph().maybeAddOrUnique(PiNode.create(object(), snippetReplaceeStamp, null));
317 replaceAndDelete(value);
318 }
319 }
320
321 /**
322 * A stamp for {@link Placeholder} nodes which are only used in snippets. It is replaced by an
323 * actual stamp when the snippet is instantiated.
324 */
325 public static final class PlaceholderStamp extends ObjectStamp {
326 private static final PlaceholderStamp SINGLETON = new PlaceholderStamp();
327
328 public static PlaceholderStamp singleton() {
329 return SINGLETON;
330 }
331
332 private PlaceholderStamp() {
333 super(null, false, false, false);
334 }
335
336 @Override
337 public int hashCode() {
338 return System.identityHashCode(this);
339 }
340
341 @Override
342 public boolean equals(Object obj) {
343 return this == obj;
344 }
345
346 @Override
347 public String toString() {
348 return "PlaceholderStamp";
349 }
350 }
351 }