Mercurial > hg > truffle
comparison graal/com.oracle.jvmci.hotspot/src/com/oracle/jvmci/hotspot/HotSpotConstantReflectionProvider.java @ 21551:5324104ac4f3
moved com.oracle.graal.hotspot.jvmci classes to com.oracle.jvmci.hotspot module (JBS:GRAAL-53)
author | Doug Simon <doug.simon@oracle.com> |
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date | Tue, 26 May 2015 17:13:37 +0200 |
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21550:f48a6cea31eb | 21551:5324104ac4f3 |
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1 /* | |
2 * Copyright (c) 2011, 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 package com.oracle.jvmci.hotspot; | |
24 | |
25 import static com.oracle.jvmci.hotspot.HotSpotConstantReflectionProvider.Options.*; | |
26 | |
27 import java.lang.reflect.*; | |
28 | |
29 import com.oracle.graal.api.meta.*; | |
30 import com.oracle.graal.options.*; | |
31 | |
32 /** | |
33 * HotSpot implementation of {@link ConstantReflectionProvider}. | |
34 */ | |
35 public class HotSpotConstantReflectionProvider implements ConstantReflectionProvider, HotSpotProxified { | |
36 | |
37 static class Options { | |
38 //@formatter:off | |
39 @Option(help = "Constant fold final fields with default values.", type = OptionType.Debug) | |
40 public static final OptionValue<Boolean> TrustFinalDefaultFields = new OptionValue<>(true); | |
41 //@formatter:on | |
42 } | |
43 | |
44 protected final HotSpotJVMCIRuntimeProvider runtime; | |
45 protected final HotSpotMethodHandleAccessProvider methodHandleAccess; | |
46 protected final HotSpotMemoryAccessProviderImpl memoryAccess; | |
47 | |
48 public HotSpotConstantReflectionProvider(HotSpotJVMCIRuntimeProvider runtime) { | |
49 this.runtime = runtime; | |
50 this.methodHandleAccess = new HotSpotMethodHandleAccessProvider(this); | |
51 this.memoryAccess = new HotSpotMemoryAccessProviderImpl(runtime); | |
52 } | |
53 | |
54 public MethodHandleAccessProvider getMethodHandleAccess() { | |
55 return methodHandleAccess; | |
56 } | |
57 | |
58 @Override | |
59 public MemoryAccessProvider getMemoryAccessProvider() { | |
60 return memoryAccess; | |
61 } | |
62 | |
63 @Override | |
64 public Boolean constantEquals(Constant x, Constant y) { | |
65 if (x == y) { | |
66 return true; | |
67 } else if (x instanceof HotSpotObjectConstantImpl) { | |
68 return y instanceof HotSpotObjectConstantImpl && ((HotSpotObjectConstantImpl) x).object() == ((HotSpotObjectConstantImpl) y).object(); | |
69 } else { | |
70 return x.equals(y); | |
71 } | |
72 } | |
73 | |
74 @Override | |
75 public Integer readArrayLength(JavaConstant array) { | |
76 if (array.getKind() != Kind.Object || array.isNull()) { | |
77 return null; | |
78 } | |
79 | |
80 Object arrayObject = ((HotSpotObjectConstantImpl) array).object(); | |
81 if (!arrayObject.getClass().isArray()) { | |
82 return null; | |
83 } | |
84 return Array.getLength(arrayObject); | |
85 } | |
86 | |
87 public JavaConstant readConstantArrayElement(JavaConstant array, int index) { | |
88 if (array instanceof HotSpotObjectConstantImpl && ((HotSpotObjectConstantImpl) array).getStableDimension() > 0) { | |
89 JavaConstant element = readArrayElement(array, index); | |
90 if (element != null && (((HotSpotObjectConstantImpl) array).isDefaultStable() || !element.isDefaultForKind())) { | |
91 return element; | |
92 } | |
93 } | |
94 return null; | |
95 } | |
96 | |
97 /** | |
98 * Try to convert {@code offset} into an an index into {@code array}. | |
99 * | |
100 * @return -1 if the offset isn't within the array or the computed index | |
101 */ | |
102 private int indexForOffset(JavaConstant array, long offset) { | |
103 if (array.getKind() != Kind.Object || array.isNull()) { | |
104 return -1; | |
105 } | |
106 Class<?> componentType = ((HotSpotObjectConstantImpl) array).object().getClass().getComponentType(); | |
107 Kind kind = runtime.getHostJVMCIBackend().getMetaAccess().lookupJavaType(componentType).getKind(); | |
108 int arraybase = runtime.getArrayBaseOffset(kind); | |
109 int scale = runtime.getArrayIndexScale(kind); | |
110 if (offset < arraybase) { | |
111 return -1; | |
112 } | |
113 long index = offset - arraybase; | |
114 if (index % scale != 0) { | |
115 return -1; | |
116 } | |
117 long result = index / scale; | |
118 if (result >= Integer.MAX_VALUE) { | |
119 return -1; | |
120 } | |
121 return (int) result; | |
122 } | |
123 | |
124 public JavaConstant readConstantArrayElementForOffset(JavaConstant array, long offset) { | |
125 if (array instanceof HotSpotObjectConstantImpl && ((HotSpotObjectConstantImpl) array).getStableDimension() > 0) { | |
126 return readConstantArrayElement(array, indexForOffset(array, offset)); | |
127 } | |
128 return null; | |
129 } | |
130 | |
131 @Override | |
132 public JavaConstant readArrayElement(JavaConstant array, int index) { | |
133 if (array.getKind() != Kind.Object || array.isNull()) { | |
134 return null; | |
135 } | |
136 Object a = ((HotSpotObjectConstantImpl) array).object(); | |
137 | |
138 if (index < 0 || index >= Array.getLength(a)) { | |
139 return null; | |
140 } | |
141 | |
142 if (a instanceof Object[]) { | |
143 Object element = ((Object[]) a)[index]; | |
144 if (((HotSpotObjectConstantImpl) array).getStableDimension() > 1) { | |
145 return HotSpotObjectConstantImpl.forStableArray(element, ((HotSpotObjectConstantImpl) array).getStableDimension() - 1, ((HotSpotObjectConstantImpl) array).isDefaultStable()); | |
146 } else { | |
147 return HotSpotObjectConstantImpl.forObject(element); | |
148 } | |
149 } else { | |
150 return JavaConstant.forBoxedPrimitive(Array.get(a, index)); | |
151 } | |
152 } | |
153 | |
154 /** | |
155 * Check if the constant is a boxed value that is guaranteed to be cached by the platform. | |
156 * Otherwise the generated code might be the only reference to the boxed value and since object | |
157 * references from nmethods are weak this can cause GC problems. | |
158 * | |
159 * @param source | |
160 * @return true if the box is cached | |
161 */ | |
162 private static boolean isBoxCached(JavaConstant source) { | |
163 switch (source.getKind()) { | |
164 case Boolean: | |
165 return true; | |
166 case Char: | |
167 return source.asInt() <= 127; | |
168 case Byte: | |
169 case Short: | |
170 case Int: | |
171 return source.asInt() >= -128 && source.asInt() <= 127; | |
172 case Long: | |
173 return source.asLong() >= -128 && source.asLong() <= 127; | |
174 case Float: | |
175 case Double: | |
176 return false; | |
177 default: | |
178 throw new IllegalArgumentException("unexpected kind " + source.getKind()); | |
179 } | |
180 } | |
181 | |
182 @Override | |
183 public JavaConstant boxPrimitive(JavaConstant source) { | |
184 if (!source.getKind().isPrimitive() || !isBoxCached(source)) { | |
185 return null; | |
186 } | |
187 return HotSpotObjectConstantImpl.forObject(source.asBoxedPrimitive()); | |
188 } | |
189 | |
190 @Override | |
191 public JavaConstant unboxPrimitive(JavaConstant source) { | |
192 if (!source.getKind().isObject()) { | |
193 return null; | |
194 } | |
195 if (source.isNull()) { | |
196 return null; | |
197 } | |
198 return JavaConstant.forBoxedPrimitive(((HotSpotObjectConstantImpl) source).object()); | |
199 } | |
200 | |
201 public JavaConstant forString(String value) { | |
202 return HotSpotObjectConstantImpl.forObject(value); | |
203 } | |
204 | |
205 @Override | |
206 public ResolvedJavaType asJavaType(Constant constant) { | |
207 if (constant instanceof HotSpotObjectConstant) { | |
208 Object obj = ((HotSpotObjectConstantImpl) constant).object(); | |
209 if (obj instanceof Class) { | |
210 return runtime.getHostJVMCIBackend().getMetaAccess().lookupJavaType((Class<?>) obj); | |
211 } | |
212 } | |
213 if (constant instanceof HotSpotMetaspaceConstant) { | |
214 Object obj = HotSpotMetaspaceConstantImpl.getMetaspaceObject(constant); | |
215 if (obj instanceof HotSpotResolvedObjectTypeImpl) { | |
216 return (ResolvedJavaType) obj; | |
217 } | |
218 } | |
219 return null; | |
220 } | |
221 | |
222 private static final String SystemClassName = "Ljava/lang/System;"; | |
223 | |
224 /** | |
225 * Determines if a static field is constant for the purpose of | |
226 * {@link #readConstantFieldValue(JavaField, JavaConstant)}. | |
227 */ | |
228 protected boolean isStaticFieldConstant(HotSpotResolvedJavaField staticField) { | |
229 if (staticField.isFinal() || staticField.isStable()) { | |
230 ResolvedJavaType holder = staticField.getDeclaringClass(); | |
231 if (holder.isInitialized() && !holder.getName().equals(SystemClassName)) { | |
232 return true; | |
233 } | |
234 } | |
235 return false; | |
236 } | |
237 | |
238 /** | |
239 * Determines if a value read from a {@code final} instance field is considered constant. The | |
240 * implementation in {@link HotSpotConstantReflectionProvider} returns true if {@code value} is | |
241 * not the {@link JavaConstant#isDefaultForKind default value} for its kind or if | |
242 * {@link Options#TrustFinalDefaultFields} is true. | |
243 * | |
244 * @param value a value read from a {@code final} instance field | |
245 * @param receiverClass the {@link Object#getClass() class} of object from which the | |
246 * {@code value} was read | |
247 */ | |
248 protected boolean isFinalInstanceFieldValueConstant(JavaConstant value, Class<?> receiverClass) { | |
249 return !value.isDefaultForKind() || TrustFinalDefaultFields.getValue(); | |
250 } | |
251 | |
252 /** | |
253 * Determines if a value read from a {@link Stable} instance field is considered constant. The | |
254 * implementation in {@link HotSpotConstantReflectionProvider} returns true if {@code value} is | |
255 * not the {@link JavaConstant#isDefaultForKind default value} for its kind. | |
256 * | |
257 * @param value a value read from a {@link Stable} field | |
258 * @param receiverClass the {@link Object#getClass() class} of object from which the | |
259 * {@code value} was read | |
260 */ | |
261 protected boolean isStableInstanceFieldValueConstant(JavaConstant value, Class<?> receiverClass) { | |
262 return !value.isDefaultForKind(); | |
263 } | |
264 | |
265 /** | |
266 * {@inheritDoc} | |
267 * <p> | |
268 * The {@code value} field in {@link OptionValue} is considered constant if the type of | |
269 * {@code receiver} is (assignable to) {@link StableOptionValue}. | |
270 */ | |
271 public JavaConstant readConstantFieldValue(JavaField field, JavaConstant receiver) { | |
272 HotSpotResolvedJavaField hotspotField = (HotSpotResolvedJavaField) field; | |
273 | |
274 if (hotspotField.isStatic()) { | |
275 if (isStaticFieldConstant(hotspotField)) { | |
276 JavaConstant value = readFieldValue(field, receiver); | |
277 if (hotspotField.isFinal() || !value.isDefaultForKind()) { | |
278 return value; | |
279 } | |
280 } | |
281 } else { | |
282 /* | |
283 * for non-static final fields, we must assume that they are only initialized if they | |
284 * have a non-default value. | |
285 */ | |
286 Object object = receiver.isNull() ? null : ((HotSpotObjectConstantImpl) receiver).object(); | |
287 | |
288 // Canonicalization may attempt to process an unsafe read before | |
289 // processing a guard (e.g. a null check or a type check) for this read | |
290 // so we need to check the object being read | |
291 if (object != null) { | |
292 if (hotspotField.isFinal()) { | |
293 if (hotspotField.isInObject(object)) { | |
294 JavaConstant value = readFieldValue(field, receiver); | |
295 if (isFinalInstanceFieldValueConstant(value, object.getClass())) { | |
296 return value; | |
297 } | |
298 } | |
299 } else if (hotspotField.isStable()) { | |
300 if (hotspotField.isInObject(object)) { | |
301 JavaConstant value = readFieldValue(field, receiver); | |
302 if (isStableInstanceFieldValueConstant(value, object.getClass())) { | |
303 return value; | |
304 } | |
305 } | |
306 } else { | |
307 Class<?> clazz = object.getClass(); | |
308 if (StableOptionValue.class.isAssignableFrom(clazz)) { | |
309 if (hotspotField.isInObject(object) && hotspotField.getName().equals("value")) { | |
310 StableOptionValue<?> option = (StableOptionValue<?>) object; | |
311 return HotSpotObjectConstantImpl.forObject(option.getValue()); | |
312 } | |
313 } | |
314 } | |
315 } | |
316 } | |
317 return null; | |
318 } | |
319 | |
320 public JavaConstant readFieldValue(JavaField field, JavaConstant receiver) { | |
321 HotSpotResolvedJavaField hotspotField = (HotSpotResolvedJavaField) field; | |
322 if (!hotspotField.isStable()) { | |
323 return readNonStableFieldValue(field, receiver); | |
324 } else { | |
325 return readStableFieldValue(field, receiver, false); | |
326 } | |
327 } | |
328 | |
329 private JavaConstant readNonStableFieldValue(JavaField field, JavaConstant receiver) { | |
330 HotSpotResolvedJavaField hotspotField = (HotSpotResolvedJavaField) field; | |
331 if (hotspotField.isStatic()) { | |
332 HotSpotResolvedJavaType holder = (HotSpotResolvedJavaType) hotspotField.getDeclaringClass(); | |
333 if (holder.isInitialized()) { | |
334 return memoryAccess.readUnsafeConstant(hotspotField.getKind(), HotSpotObjectConstantImpl.forObject(holder.mirror()), hotspotField.offset()); | |
335 } | |
336 } else { | |
337 if (receiver.isNonNull() && hotspotField.isInObject(((HotSpotObjectConstantImpl) receiver).object())) { | |
338 return memoryAccess.readUnsafeConstant(hotspotField.getKind(), receiver, hotspotField.offset()); | |
339 } | |
340 } | |
341 return null; | |
342 } | |
343 | |
344 public JavaConstant readStableFieldValue(JavaField field, JavaConstant receiver, boolean isDefaultStable) { | |
345 JavaConstant fieldValue = readNonStableFieldValue(field, receiver); | |
346 if (fieldValue.isNonNull()) { | |
347 JavaType declaredType = field.getType(); | |
348 if (declaredType.getComponentType() != null) { | |
349 int stableDimension = getArrayDimension(declaredType); | |
350 return HotSpotObjectConstantImpl.forStableArray(((HotSpotObjectConstantImpl) fieldValue).object(), stableDimension, isDefaultStable); | |
351 } | |
352 } | |
353 return fieldValue; | |
354 } | |
355 | |
356 private static int getArrayDimension(JavaType type) { | |
357 int dimensions = 0; | |
358 JavaType componentType = type; | |
359 while ((componentType = componentType.getComponentType()) != null) { | |
360 dimensions++; | |
361 } | |
362 return dimensions; | |
363 } | |
364 } |