001 /*
002 * This file is part of the Jikes RVM project (http://jikesrvm.org).
003 *
004 * This file is licensed to You under the Eclipse Public License (EPL);
005 * You may not use this file except in compliance with the License. You
006 * may obtain a copy of the License at
007 *
008 * http://www.opensource.org/licenses/eclipse-1.0.php
009 *
010 * See the COPYRIGHT.txt file distributed with this work for information
011 * regarding copyright ownership.
012 */
013 package org.jikesrvm.classloader;
014
015 import org.jikesrvm.VM;
016 import org.jikesrvm.Constants;
017 import org.vmmagic.pragma.Uninterruptible;
018 import org.vmmagic.unboxed.Offset;
019
020 /**
021 * A field or method of a java class.
022 */
023 public abstract class RVMMember extends AnnotatedElement implements Constants, ClassLoaderConstants {
024
025 /** Initial value for a field offset - indicates field not laid out. */
026 private static final int NO_OFFSET = Short.MIN_VALUE + 1;
027
028 /**
029 * The class that declared this member, available by calling
030 * getDeclaringClass once the class is loaded.
031 */
032 private final TypeReference declaringClass;
033
034 /**
035 * The canonical MemberReference for this member
036 */
037 protected final MemberReference memRef;
038
039 /**
040 * The modifiers associated with this member.
041 */
042 protected final short modifiers;
043
044 /**
045 * The signature is a string representing the generic type for this
046 * field or method declaration, may be null
047 */
048 private final Atom signature;
049
050 /**
051 * The member's jtoc/obj/tib offset in bytes.
052 * Set by {@link RVMClass#resolve()}
053 */
054 protected int offset;
055
056 /**
057 * NOTE: Only {@link RVMClass} is allowed to create an instance of a RVMMember.
058 *
059 * @param declaringClass the TypeReference object of the class that declared this member
060 * @param memRef the canonical memberReference for this member.
061 * @param modifiers modifiers associated with this member.
062 * @param signature generic type of this member
063 * @param annotations array of runtime visible annotations
064 */
065 protected RVMMember(TypeReference declaringClass, MemberReference memRef, short modifiers, Atom signature,
066 RVMAnnotation[] annotations) {
067 super(annotations);
068 this.declaringClass = declaringClass;
069 this.memRef = memRef;
070 this.modifiers = modifiers;
071 this.signature = signature;
072 this.offset = NO_OFFSET; // invalid value. Set to valid value during RVMClass.resolve()
073 }
074
075 //--------------------------------------------------------------------//
076 // Section 1. //
077 // The following are available after class loading. //
078 //--------------------------------------------------------------------//
079
080 /**
081 * Class that declared this field or method. Not available before
082 * the class is loaded.
083 */
084 @Uninterruptible
085 public final RVMClass getDeclaringClass() {
086 return declaringClass.peekType().asClass();
087 }
088
089 /**
090 * Canonical member reference for this member.
091 */
092 @Uninterruptible
093 public final MemberReference getMemberRef() {
094 return memRef;
095 }
096
097 /**
098 * Name of this member.
099 */
100 @Uninterruptible
101 public final Atom getName() {
102 return memRef.getName();
103 }
104
105 /**
106 * Descriptor for this member.
107 * something like "I" for a field or "(I)V" for a method.
108 */
109 @Uninterruptible
110 public final Atom getDescriptor() {
111 return memRef.getDescriptor();
112 }
113
114 /**
115 * Generic type for member
116 */
117 public final Atom getSignature() {
118 return signature;
119 }
120
121 /**
122 * Get a unique id for this member.
123 * The id is the id of the canonical MemberReference for this member
124 * and thus may be used to find the member by first finding the member reference.
125 */
126 @Uninterruptible
127 public final int getId() {
128 return memRef.getId();
129 }
130
131 /*
132 * Define hashcode in terms of Atom.hashCode to enable
133 * consistent hash codes during bootImage writing and run-time.
134 */
135 @Override
136 public int hashCode() {
137 return memRef.hashCode();
138 }
139
140 @Override
141 public final String toString() {
142 return declaringClass + "." + getName() + " " + getDescriptor();
143 }
144
145 /**
146 * Usable from classes outside its package?
147 */
148 public final boolean isPublic() {
149 return (modifiers & ACC_PUBLIC) != 0;
150 }
151
152 /**
153 * Usable only from this class?
154 */
155 public final boolean isPrivate() {
156 return (modifiers & ACC_PRIVATE) != 0;
157 }
158
159 /**
160 * Usable from subclasses?
161 */
162 public final boolean isProtected() {
163 return (modifiers & ACC_PROTECTED) != 0;
164 }
165
166 /**
167 * Get the member's modifiers.
168 */
169 public final int getModifiers() {
170 return modifiers;
171 }
172
173 /**
174 * Has the field been laid out in the object yet ?
175 *
176 * @return {@code true} if the field has been assigned an offset, {@code false} if not
177 */
178 public final boolean hasOffset() {
179 return !(offset == NO_OFFSET);
180 }
181
182 //------------------------------------------------------------------//
183 // Section 2. //
184 // The following are available after the declaring class has been //
185 // "resolved". //
186 //------------------------------------------------------------------//
187
188 /**
189 * Offset of this field or method, in bytes.
190 * <ul>
191 * <li> For a static field: offset of field from start of jtoc
192 * <li> For a static method: offset of code object reference from start of jtoc
193 * <li> For a non-static field: offset of field from start of object
194 * <li> For a non-static method: offset of code object reference from start of tib
195 * </ul>
196 */
197 @Uninterruptible
198 public final Offset getOffset() {
199 if (VM.VerifyAssertions) VM._assert(declaringClass!=null);
200 if (VM.VerifyAssertions) VM._assert(declaringClass.isLoaded());
201 if (VM.VerifyAssertions) VM._assert(offset != NO_OFFSET);
202 return Offset.fromIntSignExtend(offset);
203 }
204
205 /**
206 * Only meant to be used by ObjectModel.layoutInstanceFields.
207 * TODO: refactor system so this functionality is in the classloader package
208 * and this method doesn't have to be final.
209 */
210 public final void setOffset(Offset off) {
211 offset = off.toInt();
212 }
213 }
214