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.internal.vm.annotation.Stable;
  32 import jdk.vm.ci.common.JVMCIError;
  33 import jdk.vm.ci.hotspot.HotSpotJVMCIRuntime.Option;
  34 import jdk.vm.ci.meta.JavaType;
  35 import jdk.vm.ci.meta.LocationIdentity;
  36 import jdk.vm.ci.meta.MetaAccessProvider;
  37 import jdk.vm.ci.meta.ModifiersProvider;
  38 import jdk.vm.ci.meta.ResolvedJavaField;
  39 import jdk.vm.ci.meta.ResolvedJavaType;
  40 
  41 /**
  42  * Represents a field in a HotSpot type.
  43  */
  44 class HotSpotResolvedJavaFieldImpl implements HotSpotResolvedJavaField, HotSpotProxified {
  45 
  46     private final HotSpotResolvedObjectTypeImpl holder;
  47     private final String name;
  48     private JavaType type;
  49     private final int offset;
  50 
  51     /**
  52      * This value contains all flags as stored in the VM including internal ones.
  53      */
  54     private final int modifiers;
  55     private final LocationIdentity locationIdentity = new FieldLocationIdentity(this);
  56 
  57     public static class FieldLocationIdentity extends LocationIdentity {
  58         HotSpotResolvedJavaField inner;
  59 
  60         FieldLocationIdentity(HotSpotResolvedJavaFieldImpl inner) {
  61             this.inner = inner;
  62         }
  63 
  64         @Override
  65         public boolean isImmutable() {
  66             return false;
  67         }
  68 
  69         @Override
  70         public boolean equals(Object obj) {
  71             if (this == obj) {
  72                 return true;
  73             }
  74             if (obj instanceof FieldLocationIdentity) {
  75                 FieldLocationIdentity fieldLocationIdentity = (FieldLocationIdentity) obj;
  76                 return inner.equals(fieldLocationIdentity.inner);
  77 
  78             }
  79             return false;
  80         }
  81 
  82         @Override
  83         public int hashCode() {
  84             return inner.hashCode();
  85         }
  86 
  87         @Override
  88         public String toString() {
  89             return inner.getName();
  90         }
  91     }
  92 
  93     HotSpotResolvedJavaFieldImpl(HotSpotResolvedObjectTypeImpl holder, String name, JavaType type, long offset, int modifiers) {
  94         this.holder = holder;
  95         this.name = name;
  96         this.type = type;
  97         assert offset != -1;
  98         assert offset == (int) offset : "offset larger than int";
  99         this.offset = (int) offset;
 100         this.modifiers = modifiers;
 101     }
 102 
 103     @Override
 104     public boolean equals(Object obj) {
 105         if (this == obj) {
 106             return true;
 107         }
 108         if (obj instanceof HotSpotResolvedJavaField) {
 109             HotSpotResolvedJavaFieldImpl that = (HotSpotResolvedJavaFieldImpl) obj;
 110             if (that.offset != this.offset || that.isStatic() != this.isStatic()) {
 111                 return false;
 112             } else if (this.holder.equals(that.holder)) {
 113                 assert this.name.equals(that.name) && this.type.equals(that.type);
 114                 return true;
 115             }
 116         }
 117         return false;
 118     }
 119 
 120     @Override
 121     public int hashCode() {
 122         return name.hashCode();
 123     }
 124 
 125     @Override
 126     public int getModifiers() {
 127         return modifiers & ModifiersProvider.jvmFieldModifiers();
 128     }
 129 
 130     @Override
 131     public boolean isInternal() {
 132         return (modifiers & config().jvmAccFieldInternal) != 0;
 133     }
 134 
 135     /**
 136      * Determines if a given object contains this field.
 137      *
 138      * @return true iff this is a non-static field and its declaring class is assignable from
 139      *         {@code object}'s class
 140      */
 141     public boolean isInObject(Object object) {
 142         if (isStatic()) {
 143             return false;
 144         }
 145         return getDeclaringClass().isAssignableFrom(HotSpotResolvedObjectTypeImpl.fromObjectClass(object.getClass()));
 146     }
 147 
 148     @Override
 149     public HotSpotResolvedObjectTypeImpl getDeclaringClass() {
 150         return holder;
 151     }
 152 
 153     @Override
 154     public String getName() {
 155         return name;
 156     }
 157 
 158     @Override
 159     public JavaType getType() {
 160         // Pull field into local variable to prevent a race causing
 161         // a ClassCastException below
 162         JavaType currentType = type;
 163         if (currentType instanceof HotSpotUnresolvedJavaType) {
 164             // Don't allow unresolved types to hang around forever
 165             HotSpotUnresolvedJavaType unresolvedType = (HotSpotUnresolvedJavaType) currentType;
 166             ResolvedJavaType resolved = unresolvedType.reresolve(holder);
 167             if (resolved != null) {
 168                 type = resolved;
 169             }
 170         }
 171         return type;
 172     }
 173 
 174     public int offset() {
 175         return offset;
 176     }
 177 
 178     @Override
 179     public String toString() {
 180         return format("HotSpotField<%H.%n %t:") + offset + ">";
 181     }
 182 
 183     @Override
 184     public boolean isSynthetic() {
 185         return (config().jvmAccSynthetic & modifiers) != 0;
 186     }
 187 
 188     /**
 189      * Checks if this field has the {@link Stable} annotation.
 190      *
 191      * @return true if field has {@link Stable} annotation, false otherwise
 192      */
 193     public boolean isStable() {
 194         if ((config().jvmAccFieldStable & modifiers) != 0) {
 195             return true;
 196         }
 197         assert getAnnotation(Stable.class) == null;
 198         if (Option.ImplicitStableValues.getBoolean() && isImplicitStableField()) {
 199             return true;
 200         }
 201         return false;
 202     }
 203 
 204     @Override
 205     public Annotation[] getAnnotations() {
 206         Field javaField = toJava();
 207         if (javaField != null) {
 208             return javaField.getAnnotations();
 209         }
 210         return new Annotation[0];
 211     }
 212 
 213     @Override
 214     public Annotation[] getDeclaredAnnotations() {
 215         Field javaField = toJava();
 216         if (javaField != null) {
 217             return javaField.getDeclaredAnnotations();
 218         }
 219         return new Annotation[0];
 220     }
 221 
 222     @Override
 223     public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
 224         Field javaField = toJava();
 225         if (javaField != null) {
 226             return javaField.getAnnotation(annotationClass);
 227         }
 228         return null;
 229     }
 230 
 231     private Field toJavaCache;
 232 
 233     private Field toJava() {
 234         if (toJavaCache != null) {
 235             return toJavaCache;
 236         }
 237 
 238         if (isInternal()) {
 239             return null;
 240         }
 241         try {
 242             return toJavaCache = holder.mirror().getDeclaredField(name);
 243         } catch (NoSuchFieldException | NoClassDefFoundError e) {
 244             return null;
 245         }
 246     }
 247 
 248     private boolean isArray() {
 249         JavaType fieldType = getType();
 250         return fieldType instanceof ResolvedJavaType && ((ResolvedJavaType) fieldType).isArray();
 251     }
 252 
 253     private boolean isImplicitStableField() {
 254         if (isSyntheticEnumSwitchMap()) {
 255             return true;
 256         }
 257         if (isWellKnownImplicitStableField()) {
 258             return true;
 259         }
 260         return false;
 261     }
 262 
 263     public boolean isDefaultStable() {
 264         assert this.isStable();
 265         if (isSyntheticEnumSwitchMap()) {
 266             return true;
 267         }
 268         return false;
 269     }
 270 
 271     private boolean isSyntheticEnumSwitchMap() {
 272         if (isSynthetic() && isStatic() && isArray()) {
 273             if (isFinal() && name.equals("$VALUES") || name.equals("ENUM$VALUES")) {
 274                 // generated int[] field for EnumClass::values()
 275                 return true;
 276             } else if (name.startsWith("$SwitchMap$") || name.startsWith("$SWITCH_TABLE$")) {
 277                 // javac and ecj generate a static field in an inner class for a switch on an enum
 278                 // named $SwitchMap$p$k$g$EnumClass and $SWITCH_TABLE$p$k$g$EnumClass, respectively
 279                 return true;
 280             }
 281         }
 282         return false;
 283     }
 284 
 285     private boolean isWellKnownImplicitStableField() {
 286         return WellKnownImplicitStableField.test(this);
 287     }
 288 
 289     static class WellKnownImplicitStableField {
 290         /**
 291          * @return {@code true} if the field is a well-known stable field.
 292          */
 293         public static boolean test(HotSpotResolvedJavaField field) {
 294             return field.equals(STRING_VALUE_FIELD);
 295         }
 296 
 297         private static final ResolvedJavaField STRING_VALUE_FIELD;
 298 
 299         static {
 300             try {
 301                 MetaAccessProvider metaAccess = runtime().getHostJVMCIBackend().getMetaAccess();
 302                 STRING_VALUE_FIELD = metaAccess.lookupJavaField(String.class.getDeclaredField("value"));
 303             } catch (SecurityException | NoSuchFieldException e) {
 304                 throw new JVMCIError(e);
 305             }
 306         }
 307     }
 308 
 309     public LocationIdentity getLocationIdentity() {
 310         return locationIdentity;
 311     }
 312 }