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