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 jdk.vm.ci.hotspot;
24
25 import static jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.runtime;
26 import static jdk.vm.ci.hotspot.HotSpotVMConfig.config;
27
28 import java.lang.annotation.Annotation;
29 import java.lang.reflect.Field;
30
31 import jdk.vm.ci.common.JVMCIError;
32 import jdk.vm.ci.meta.JavaType;
33 import jdk.vm.ci.meta.LocationIdentity;
34 import jdk.vm.ci.meta.MetaAccessProvider;
35 import jdk.vm.ci.meta.ModifiersProvider;
36 import jdk.vm.ci.meta.ResolvedJavaField;
37 import jdk.vm.ci.meta.ResolvedJavaType;
38 import jdk.vm.ci.options.Option;
39 import jdk.vm.ci.options.OptionType;
40 import jdk.vm.ci.options.OptionValue;
41
42 /**
43 * Represents a field in a HotSpot type.
44 */
45 class HotSpotResolvedJavaFieldImpl implements HotSpotResolvedJavaField, HotSpotProxified {
46
47 static class Options {
48 //@formatter:off
49 @Option(help = "Mark well-known stable fields as such.", type = OptionType.Debug)
50 public static final OptionValue<Boolean> ImplicitStableValues = new OptionValue<>(true);
51 //@formatter:on
52 }
53
54 private final HotSpotResolvedObjectTypeImpl holder;
55 private final String name;
56 private JavaType type;
57 private final int offset;
58
59 /**
60 * This value contains all flags as stored in the VM including internal ones.
61 */
62 private final int modifiers;
63 private final LocationIdentity locationIdentity = new FieldLocationIdentity(this);
64
65 public static class FieldLocationIdentity extends LocationIdentity {
66 HotSpotResolvedJavaField inner;
67
68 public FieldLocationIdentity(HotSpotResolvedJavaFieldImpl inner) {
69 this.inner = inner;
70 }
71
72 @Override
73 public boolean isImmutable() {
74 return false;
75 }
76
77 @Override
78 public boolean equals(Object obj) {
79 if (this == obj) {
80 return true;
81 }
82 if (obj instanceof FieldLocationIdentity) {
83 FieldLocationIdentity fieldLocationIdentity = (FieldLocationIdentity) obj;
84 return inner.equals(fieldLocationIdentity.inner);
85
86 }
87 return false;
88 }
89
90 @Override
91 public int hashCode() {
92 return inner.hashCode();
93 }
94
95 @Override
96 public String toString() {
97 return inner.getName();
98 }
99 }
100
101 HotSpotResolvedJavaFieldImpl(HotSpotResolvedObjectTypeImpl holder, String name, JavaType type, long offset, int modifiers) {
102 this.holder = holder;
103 this.name = name;
104 this.type = type;
105 assert offset != -1;
106 assert offset == (int) offset : "offset larger than int";
107 this.offset = (int) offset;
108 this.modifiers = modifiers;
109 }
110
111 @Override
112 public boolean equals(Object obj) {
113 if (this == obj) {
114 return true;
115 }
116 if (obj instanceof HotSpotResolvedJavaField) {
117 HotSpotResolvedJavaFieldImpl that = (HotSpotResolvedJavaFieldImpl) obj;
118 if (that.offset != this.offset || that.isStatic() != this.isStatic()) {
119 return false;
120 } else if (this.holder.equals(that.holder)) {
121 assert this.name.equals(that.name) && this.type.equals(that.type);
122 return true;
123 }
124 }
125 return false;
126 }
127
128 @Override
129 public int hashCode() {
130 return name.hashCode();
131 }
132
133 @Override
134 public int getModifiers() {
135 return modifiers & ModifiersProvider.jvmFieldModifiers();
136 }
137
138 @Override
139 public boolean isInternal() {
140 return (modifiers & config().jvmAccFieldInternal) != 0;
141 }
142
143 /**
144 * Determines if a given object contains this field.
145 *
146 * @return true iff this is a non-static field and its declaring class is assignable from
147 * {@code object}'s class
148 */
149 public boolean isInObject(Object object) {
150 if (isStatic()) {
151 return false;
152 }
153 return getDeclaringClass().isAssignableFrom(HotSpotResolvedObjectTypeImpl.fromObjectClass(object.getClass()));
154 }
155
156 @Override
157 public HotSpotResolvedObjectTypeImpl getDeclaringClass() {
158 return holder;
159 }
160
161 @Override
162 public String getName() {
163 return name;
164 }
165
166 @Override
167 public JavaType getType() {
168 // Pull field into local variable to prevent a race causing
169 // a ClassCastException below
170 JavaType currentType = type;
171 if (currentType instanceof HotSpotUnresolvedJavaType) {
172 // Don't allow unresolved types to hang around forever
173 HotSpotUnresolvedJavaType unresolvedType = (HotSpotUnresolvedJavaType) currentType;
174 ResolvedJavaType resolved = unresolvedType.reresolve(holder);
175 if (resolved != null) {
176 type = resolved;
177 }
178 }
179 return type;
180 }
181
182 public int offset() {
183 return offset;
184 }
185
186 @Override
187 public String toString() {
188 return format("HotSpotField<%H.%n %t:") + offset + ">";
189 }
190
191 @Override
192 public boolean isSynthetic() {
193 return (config().syntheticFlag & modifiers) != 0;
194 }
195
196 /**
197 * Checks if this field has the {@link Stable} annotation.
198 *
199 * @return true if field has {@link Stable} annotation, false otherwise
200 */
201 public boolean isStable() {
202 if ((config().jvmAccFieldStable & modifiers) != 0) {
203 return true;
204 }
205 assert getAnnotation(Stable.class) == null;
206 if (Options.ImplicitStableValues.getValue() && isImplicitStableField()) {
207 return true;
208 }
209 return false;
210 }
211
212 @Override
213 public Annotation[] getAnnotations() {
214 Field javaField = toJava();
215 if (javaField != null) {
216 return javaField.getAnnotations();
217 }
218 return new Annotation[0];
219 }
220
221 @Override
222 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
223 Field javaField = toJava();
224 if (javaField != null) {
225 return javaField.getAnnotation(annotationClass);
226 }
227 return null;
228 }
229
230 private Field toJavaCache;
231
232 private Field toJava() {
233 if (toJavaCache != null) {
234 return toJavaCache;
235 }
236
237 if (isInternal()) {
238 return null;
239 }
240 try {
241 return toJavaCache = holder.mirror().getDeclaredField(name);
242 } catch (NoSuchFieldException | NoClassDefFoundError e) {
243 return null;
244 }
245 }
246
247 private boolean isArray() {
248 JavaType fieldType = getType();
249 return fieldType instanceof ResolvedJavaType && ((ResolvedJavaType) fieldType).isArray();
250 }
251
252 private boolean isImplicitStableField() {
253 if (isSyntheticEnumSwitchMap()) {
254 return true;
255 }
256 if (isWellKnownImplicitStableField()) {
257 return true;
258 }
259 return false;
260 }
261
262 public boolean isDefaultStable() {
263 assert this.isStable();
264 if (isSyntheticEnumSwitchMap()) {
265 return true;
266 }
267 return false;
268 }
269
270 private boolean isSyntheticEnumSwitchMap() {
271 if (isSynthetic() && isStatic() && isArray()) {
272 if (isFinal() && name.equals("$VALUES") || name.equals("ENUM$VALUES")) {
273 // generated int[] field for EnumClass::values()
274 return true;
275 } else if (name.startsWith("$SwitchMap$") || name.startsWith("$SWITCH_TABLE$")) {
276 // javac and ecj generate a static field in an inner class for a switch on an enum
277 // named $SwitchMap$p$k$g$EnumClass and $SWITCH_TABLE$p$k$g$EnumClass, respectively
278 return true;
279 }
280 }
281 return false;
282 }
283
284 private boolean isWellKnownImplicitStableField() {
285 return WellKnownImplicitStableField.test(this);
286 }
287
288 static class WellKnownImplicitStableField {
289 /**
290 * @return {@code true} if the field is a well-known stable field.
291 */
292 public static boolean test(HotSpotResolvedJavaField field) {
293 return field.equals(STRING_VALUE_FIELD);
294 }
295
296 private static final ResolvedJavaField STRING_VALUE_FIELD;
297
298 static {
299 try {
300 MetaAccessProvider metaAccess = runtime().getHostJVMCIBackend().getMetaAccess();
301 STRING_VALUE_FIELD = metaAccess.lookupJavaField(String.class.getDeclaredField("value"));
302 } catch (SecurityException | NoSuchFieldException e) {
303 throw new JVMCIError(e);
304 }
305 }
306 }
307
308 public LocationIdentity getLocationIdentity() {
309 return locationIdentity;
310 }
311 }