1 /*
2 * Copyright (c) 2012, 2019, 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.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.debug.DebugContext;
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 import jdk.vm.ci.meta.JavaKind;
53 import jdk.vm.ci.meta.ResolvedJavaMethod;
54 import jdk.vm.ci.meta.ResolvedJavaType;
55
56 //JaCoCo Exclude
57
58 /**
59 * A node that changes the type of its input, usually narrowing it. For example, a {@link PiNode}
60 * refines the type of a receiver during type-guarded inlining to be the type tested by the guard.
61 *
62 * In contrast to a {@link GuardedValueNode}, a {@link PiNode} is useless as soon as the type of its
63 * input is as narrow or narrower than the {@link PiNode}'s type. The {@link PiNode}, and therefore
64 * also the scheduling restriction enforced by the guard, will go away.
65 */
66 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
67 public class PiNode extends FloatingGuardedNode implements LIRLowerable, Virtualizable, Canonicalizable, ValueProxy {
68
69 public static final NodeClass<PiNode> TYPE = NodeClass.create(PiNode.class);
70 @Input ValueNode object;
71 protected Stamp piStamp;
72
73 public ValueNode object() {
74 return object;
75 }
76
77 protected PiNode(NodeClass<? extends PiNode> c, ValueNode object, Stamp stamp, GuardingNode guard) {
78 super(c, stamp, guard);
79 this.object = object;
80 this.piStamp = stamp;
81 assert piStamp.isCompatible(object.stamp(NodeView.DEFAULT)) : "Object stamp not compatible to piStamp";
82 inferStamp();
83 }
84
85 public PiNode(ValueNode object, Stamp stamp) {
86 this(object, stamp, null);
87 }
88
89 public PiNode(ValueNode object, Stamp stamp, ValueNode guard) {
90 this(TYPE, object, stamp, (GuardingNode) guard);
91 }
92
93 public PiNode(ValueNode object, ValueNode guard) {
94 this(object, AbstractPointerStamp.pointerNonNull(object.stamp(NodeView.DEFAULT)), guard);
95 }
96
97 public PiNode(ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
98 this(object, StampFactory.object(exactType ? TypeReference.createExactTrusted(toType) : TypeReference.createWithoutAssumptions(toType),
99 nonNull || StampTool.isPointerNonNull(object.stamp(NodeView.DEFAULT))));
100 }
101
102 public static ValueNode create(ValueNode object, Stamp stamp) {
103 ValueNode value = canonical(object, stamp, null, null);
104 if (value != null) {
105 return value;
106 }
107 return new PiNode(object, stamp);
108 }
109
110 public static ValueNode create(ValueNode object, Stamp stamp, ValueNode guard) {
111 ValueNode value = canonical(object, stamp, (GuardingNode) guard, null);
112 if (value != null) {
113 return value;
114 }
115 return new PiNode(object, stamp, guard);
116 }
117
118 public static ValueNode create(ValueNode object, ValueNode guard) {
119 Stamp stamp = AbstractPointerStamp.pointerNonNull(object.stamp(NodeView.DEFAULT));
120 ValueNode value = canonical(object, stamp, (GuardingNode) guard, null);
121 if (value != null) {
122 return value;
123 }
124 return new PiNode(object, stamp, guard);
125 }
126
127 @SuppressWarnings("unused")
128 public static boolean intrinsify(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode object, ValueNode guard) {
129 Stamp stamp = AbstractPointerStamp.pointerNonNull(object.stamp(NodeView.DEFAULT));
130 ValueNode value = canonical(object, stamp, (GuardingNode) guard, null);
131 if (value == null) {
132 value = new PiNode(object, stamp, guard);
133 }
134 b.push(JavaKind.Object, b.append(value));
135 return true;
136 }
137
138 @SuppressWarnings("unused")
139 public static boolean intrinsify(GraphBuilderContext b, ResolvedJavaMethod method, ValueNode object, ResolvedJavaType toType, boolean exactType, boolean nonNull) {
140 Stamp stamp = StampFactory.object(exactType ? TypeReference.createExactTrusted(toType) : TypeReference.createWithoutAssumptions(toType),
141 nonNull || StampTool.isPointerNonNull(object.stamp(NodeView.DEFAULT)));
142 ValueNode value = canonical(object, stamp, null, null);
143 if (value == null) {
144 value = new PiNode(object, stamp);
145 }
146 b.push(JavaKind.Object, b.append(value));
147 return true;
148 }
149
150 public final Stamp piStamp() {
151 return piStamp;
152 }
153
154 public void strengthenPiStamp(Stamp newPiStamp) {
155 assert this.piStamp.join(newPiStamp).equals(newPiStamp) : "stamp can only improve";
156 this.piStamp = newPiStamp;
157 }
158
159 @Override
160 public void generate(NodeLIRBuilderTool generator) {
161 if (generator.hasOperand(object)) {
162 generator.setResult(this, generator.operand(object));
163 }
164 }
165
166 @Override
167 public boolean inferStamp() {
168 return updateStamp(computeStamp());
169 }
170
171 private Stamp computeStamp() {
172 return piStamp.improveWith(object().stamp(NodeView.DEFAULT));
173 }
174
175 @Override
176 public void virtualize(VirtualizerTool tool) {
177 ValueNode alias = tool.getAlias(object());
178 if (alias instanceof VirtualObjectNode) {
179 VirtualObjectNode virtual = (VirtualObjectNode) alias;
180 ResolvedJavaType type = StampTool.typeOrNull(this, tool.getMetaAccess());
181 if (type != null && type.isAssignableFrom(virtual.type())) {
182 tool.replaceWithVirtual(virtual);
183 } else {
184 tool.getDebug().log(DebugContext.INFO_LEVEL, "could not virtualize Pi because of type mismatch: %s %s vs %s", this, type, virtual.type());
185 }
186 }
187 }
188
189 public static ValueNode canonical(ValueNode object, Stamp stamp, GuardingNode guard, PiNode self) {
190 // Use most up to date stamp.
191 Stamp computedStamp = stamp.improveWith(object.stamp(NodeView.DEFAULT));
192
193 // The pi node does not give any additional information => skip it.
194 if (computedStamp.equals(object.stamp(NodeView.DEFAULT))) {
195 return object;
196 }
197
198 if (guard == null) {
199 // Try to merge the pi node with a load node.
200 if (object instanceof ReadNode && !object.hasMoreThanOneUsage()) {
201 ReadNode readNode = (ReadNode) object;
202 readNode.setStamp(readNode.stamp(NodeView.DEFAULT).improveWith(stamp));
203 return readNode;
204 }
205 } else {
206 for (Node n : guard.asNode().usages()) {
207 if (n instanceof PiNode && n != self) {
208 PiNode otherPi = (PiNode) n;
209 assert otherPi.guard == guard;
210 if (object == otherPi.object() && computedStamp.equals(otherPi.stamp(NodeView.DEFAULT))) {
211 /*
212 * Two PiNodes with the same guard and same result, so return the one with
213 * the more precise piStamp.
214 */
215 Stamp newStamp = stamp.join(otherPi.piStamp);
216 if (newStamp.equals(otherPi.piStamp)) {
217 return otherPi;
218 }
219 }
220 }
221 }
222 }
223 return null;
224 }
225
226 @Override
227 public Node canonical(CanonicalizerTool tool) {
228 Node value = canonical(object(), piStamp(), getGuard(), this);
229 if (value != null) {
230 return value;
231 }
232 return this;
233 }
234
235 @Override
236 public ValueNode getOriginalNode() {
237 return object;
238 }
239
240 public void setOriginalNode(ValueNode newNode) {
241 this.updateUsages(object, newNode);
242 this.object = newNode;
243 assert piStamp.isCompatible(object.stamp(NodeView.DEFAULT)) : "New object stamp not compatible to piStamp";
244 }
245
246 /**
247 * Casts an object to have an exact, non-null stamp representing {@link Class}.
248 */
249 public static Class<?> asNonNullClass(Object object) {
250 return asNonNullClassIntrinsic(object, Class.class, true, true);
251 }
252
253 /**
254 * Casts an object to have an exact, non-null stamp representing {@link Class}.
255 */
256 public static Class<?> asNonNullObject(Object object) {
257 return asNonNullClassIntrinsic(object, Object.class, false, true);
258 }
259
260 @NodeIntrinsic(PiNode.class)
261 private static native Class<?> asNonNullClassIntrinsic(Object object, @ConstantNodeParameter Class<?> toType, @ConstantNodeParameter boolean exactType, @ConstantNodeParameter boolean nonNull);
262
263 /**
264 * Changes the stamp of an object inside a snippet to be the stamp of the node replaced by the
265 * snippet.
266 */
267 @NodeIntrinsic(PiNode.Placeholder.class)
268 public static native Object piCastToSnippetReplaceeStamp(Object object);
269
270 /**
271 * Changes the stamp of an object and ensures the newly stamped value is non-null and does not
272 * float above a given guard.
273 */
274 @NodeIntrinsic
275 public static native Object piCastNonNull(Object object, GuardingNode guard);
276
277 /**
278 * Changes the stamp of an object and ensures the newly stamped value is non-null and does not
279 * float above a given guard.
280 */
281 @NodeIntrinsic
282 public static native Class<?> piCastNonNullClass(Class<?> type, GuardingNode guard);
283
284 /**
285 * Changes the stamp of an object to represent a given type and to indicate that the object is
286 * not null.
287 */
288 public static Object piCastNonNull(Object object, @ConstantNodeParameter ResolvedJavaType toType) {
289 return piCast(object, toType, false, true);
290 }
291
292 @NodeIntrinsic
293 public static native Object piCast(Object object, @ConstantNodeParameter ResolvedJavaType toType, @ConstantNodeParameter boolean exactType, @ConstantNodeParameter boolean nonNull);
294
295 /**
296 * A placeholder node in a snippet that will be replaced with a {@link PiNode} when the snippet
297 * is instantiated.
298 */
299 @NodeInfo(cycles = CYCLES_0, size = SIZE_0)
300 public static class Placeholder extends FloatingGuardedNode {
301
302 public static final NodeClass<Placeholder> TYPE = NodeClass.create(Placeholder.class);
303 @Input ValueNode object;
304
305 public ValueNode object() {
306 return object;
307 }
308
309 protected Placeholder(NodeClass<? extends Placeholder> c, ValueNode object) {
310 super(c, PlaceholderStamp.SINGLETON, null);
311 this.object = object;
312 }
313
314 public Placeholder(ValueNode object) {
315 this(TYPE, object);
316 }
317
318 /**
319 * Replaces this node with a {@link PiNode} during snippet instantiation.
320 *
321 * @param snippetReplaceeStamp the stamp of the node being replace by the snippet
322 */
323 public void makeReplacement(Stamp snippetReplaceeStamp) {
324 ValueNode value = graph().maybeAddOrUnique(PiNode.create(object(), snippetReplaceeStamp, null));
325 replaceAndDelete(value);
326 }
327 }
328
329 /**
330 * A stamp for {@link Placeholder} nodes which are only used in snippets. It is replaced by an
331 * actual stamp when the snippet is instantiated.
332 */
333 public static final class PlaceholderStamp extends ObjectStamp {
334 private static final PlaceholderStamp SINGLETON = new PlaceholderStamp();
335
336 public static PlaceholderStamp singleton() {
337 return SINGLETON;
338 }
339
340 private PlaceholderStamp() {
341 super(null, false, false, false);
342 }
343
344 @Override
345 public int hashCode() {
346 return System.identityHashCode(this);
347 }
348
349 @Override
350 public boolean equals(Object obj) {
351 return this == obj;
352 }
353
354 @Override
355 public String toString() {
356 return "PlaceholderStamp";
357 }
358 }
359 }