1 /*
2 * Copyright (c) 2011, 2014, 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.*;
26 import static jdk.vm.ci.hotspot.HotSpotResolvedJavaFieldImpl.Options.*;
27
28 import java.lang.annotation.*;
29 import java.lang.reflect.*;
30
31 import jdk.vm.ci.common.*;
32 import jdk.vm.ci.meta.*;
33 import jdk.vm.ci.options.*;
34
35 /**
36 * Represents a field in a HotSpot type.
37 */
38 public class HotSpotResolvedJavaFieldImpl implements HotSpotResolvedJavaField, HotSpotProxified {
39
40 static class Options {
41 //@formatter:off
42 @Option(help = "Mark well-known stable fields as such.", type = OptionType.Debug)
43 public static final OptionValue<Boolean> ImplicitStableValues = new OptionValue<>(true);
44 //@formatter:on
45 }
46
47 private final HotSpotResolvedObjectTypeImpl holder;
48 private final String name;
49 private JavaType type;
50 private final int offset;
51
52 /**
53 * This value contains all flags as stored in the VM including internal ones.
54 */
55 private final int modifiers;
56 private final LocationIdentity locationIdentity = new FieldLocationIdentity(this);
57
58 public static class FieldLocationIdentity extends LocationIdentity {
59 HotSpotResolvedJavaField inner;
60
61 public FieldLocationIdentity(HotSpotResolvedJavaFieldImpl inner) {
62 this.inner = inner;
63 }
64
65 @Override
66 public boolean isImmutable() {
67 return false;
68 }
69
70 @Override
71 public boolean equals(Object obj) {
72 if (this == obj) {
73 return true;
74 }
75 if (obj instanceof FieldLocationIdentity) {
76 FieldLocationIdentity fieldLocationIdentity = (FieldLocationIdentity) obj;
77 return inner.equals(fieldLocationIdentity.inner);
78
79 }
80 return false;
81 }
82
83 @Override
84 public int hashCode() {
85 return inner.hashCode();
86 }
87
88 @Override
89 public String toString() {
90 return inner.getName();
91 }
92 }
93
94 public HotSpotResolvedJavaFieldImpl(HotSpotResolvedObjectTypeImpl holder, String name, JavaType type, long offset, int modifiers) {
95 this.holder = holder;
96 this.name = name;
97 this.type = type;
98 assert offset != -1;
99 assert offset == (int) offset : "offset larger than int";
100 this.offset = (int) offset;
101 this.modifiers = modifiers;
102 }
103
104 @Override
105 public boolean equals(Object obj) {
106 if (this == obj) {
107 return true;
108 }
109 if (obj instanceof HotSpotResolvedJavaField) {
110 HotSpotResolvedJavaFieldImpl that = (HotSpotResolvedJavaFieldImpl) obj;
111 if (that.offset != this.offset || that.isStatic() != this.isStatic()) {
112 return false;
113 } else if (this.holder.equals(that.holder)) {
114 assert this.name.equals(that.name) && this.type.equals(that.type);
115 return true;
116 }
117 }
118 return false;
119 }
120
121 @Override
122 public int hashCode() {
123 return name.hashCode();
124 }
125
126 @Override
127 public int getModifiers() {
128 return modifiers & ModifiersProvider.jvmFieldModifiers();
129 }
130
131 @Override
132 public boolean isInternal() {
133 return (modifiers & runtime().getConfig().jvmAccFieldInternal) != 0;
134 }
135
136 /**
137 * Determines if a given object contains this field.
138 *
139 * @return true iff this is a non-static field and its declaring class is assignable from
140 * {@code object}'s class
141 */
142 public boolean isInObject(Object object) {
143 if (isStatic()) {
144 return false;
145 }
146 return getDeclaringClass().isAssignableFrom(HotSpotResolvedObjectTypeImpl.fromObjectClass(object.getClass()));
147 }
148
149 @Override
150 public HotSpotResolvedObjectTypeImpl getDeclaringClass() {
151 return holder;
152 }
153
154 @Override
155 public String getName() {
156 return name;
157 }
158
159 @Override
160 public JavaType getType() {
161 // Pull field into local variable to prevent a race causing
162 // a ClassCastException below
163 JavaType currentType = type;
164 if (currentType instanceof HotSpotUnresolvedJavaType) {
165 // Don't allow unresolved types to hang around forever
166 HotSpotUnresolvedJavaType unresolvedType = (HotSpotUnresolvedJavaType) currentType;
167 ResolvedJavaType resolved = unresolvedType.reresolve(holder);
168 if (resolved != null) {
169 type = resolved;
170 }
171 }
172 return type;
173 }
174
175 public int offset() {
176 return offset;
177 }
178
179 @Override
180 public String toString() {
181 return format("HotSpotField<%H.%n %t:") + offset + ">";
182 }
183
184 @Override
185 public boolean isSynthetic() {
186 return (runtime().getConfig().syntheticFlag & modifiers) != 0;
187 }
188
189 /**
190 * Checks if this field has the {@link Stable} annotation.
191 *
192 * @return true if field has {@link Stable} annotation, false otherwise
193 */
194 public boolean isStable() {
195 if ((runtime().getConfig().jvmAccFieldStable & modifiers) != 0) {
196 return true;
197 }
198 assert getAnnotation(Stable.class) == null;
199 if (ImplicitStableValues.getValue() && isImplicitStableField()) {
200 return true;
201 }
202 return false;
203 }
204
205 @Override
206 public Annotation[] getAnnotations() {
207 Field javaField = toJava();
208 if (javaField != null) {
209 return javaField.getAnnotations();
210 }
211 return new Annotation[0];
212 }
213
214 @Override
215 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
216 Field javaField = toJava();
217 if (javaField != null) {
218 return javaField.getAnnotation(annotationClass);
219 }
220 return null;
221 }
222
223 private Field toJavaCache;
224
225 private Field toJava() {
226 if (toJavaCache != null) {
227 return toJavaCache;
228 }
229
230 if (isInternal()) {
231 return null;
232 }
233 try {
234 return toJavaCache = holder.mirror().getDeclaredField(name);
235 } catch (NoSuchFieldException | NoClassDefFoundError e) {
236 return null;
237 }
238 }
239
240 private boolean isArray() {
241 JavaType fieldType = getType();
242 return fieldType instanceof ResolvedJavaType && ((ResolvedJavaType) fieldType).isArray();
243 }
244
245 private boolean isImplicitStableField() {
246 if (isSynthetic()) {
247 if (isSyntheticImplicitStableField()) {
248 return true;
249 }
250 } else if (isWellKnownImplicitStableField()) {
251 return true;
252 }
253 return false;
254 }
255
256 private boolean isSyntheticImplicitStableField() {
257 assert this.isSynthetic();
258 if (isStatic() && isArray()) {
259 if (isFinal() && name.equals("$VALUES") || name.equals("ENUM$VALUES")) {
260 // generated int[] field for EnumClass::values()
261 return true;
262 } else if (name.startsWith("$SwitchMap$") || name.startsWith("$SWITCH_TABLE$")) {
263 // javac and ecj generate a static field in an inner class for a switch on an enum
264 // named $SwitchMap$p$k$g$EnumClass and $SWITCH_TABLE$p$k$g$EnumClass, respectively
265 return true;
266 }
267 }
268 return false;
269 }
270
271 private boolean isWellKnownImplicitStableField() {
272 return WellKnownImplicitStableField.test(this);
273 }
274
275 static class WellKnownImplicitStableField {
276 /**
277 * @return {@code true} if the field is a well-known stable field.
278 */
279 public static boolean test(HotSpotResolvedJavaField field) {
280 return field.equals(STRING_VALUE_FIELD);
281 }
282
283 private static final ResolvedJavaField STRING_VALUE_FIELD;
284 static {
285 try {
286 MetaAccessProvider metaAccess = runtime().getHostJVMCIBackend().getMetaAccess();
287 STRING_VALUE_FIELD = metaAccess.lookupJavaField(String.class.getDeclaredField("value"));
288 } catch (SecurityException | NoSuchFieldException e) {
289 throw new JVMCIError(e);
290 }
291 }
292 }
293
294 public LocationIdentity getLocationIdentity() {
295 return locationIdentity;
296 }
297 }