1 /*
2 * Copyright (c) 2000, 2024, 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 */
24
25 package sun.jvm.hotspot.oops;
26
27 import java.io.*;
28 import java.util.*;
29 import sun.jvm.hotspot.debugger.*;
30 import sun.jvm.hotspot.classfile.*;
31 import sun.jvm.hotspot.runtime.*;
32 import sun.jvm.hotspot.types.*;
33 import sun.jvm.hotspot.utilities.Observable;
34 import sun.jvm.hotspot.utilities.Observer;
35
36 public class Klass extends Metadata implements ClassConstants {
37 static {
38 VM.registerVMInitializedObserver(new Observer() {
39 public void update(Observable o, Object data) {
40 initialize(VM.getVM().getTypeDataBase());
41 }
42 });
43 }
44
45 // anon-enum constants for _layout_helper.
46 public static int LH_INSTANCE_SLOW_PATH_BIT;
47 public static int LH_LOG2_ELEMENT_SIZE_SHIFT;
48 public static int LH_ELEMENT_TYPE_SHIFT;
49 public static int LH_HEADER_SIZE_SHIFT;
50 public static int LH_ARRAY_TAG_SHIFT;
51 public static int LH_ARRAY_TAG_TYPE_VALUE;
52 public static int LH_ARRAY_TAG_OBJ_VALUE;
53
54 private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
55 Type type = db.lookupType("Klass");
56 javaMirrorFieldOffset = type.getField("_java_mirror").getOffset();
57 superField = new MetadataField(type.getAddressField("_super"), 0);
58 layoutHelper = new IntField(type.getJIntField("_layout_helper"), 0);
59 name = type.getAddressField("_name");
60 accessFlags = new CIntField(type.getCIntegerField("_access_flags"), 0);
61 try {
62 traceIDField = type.getField("_trace_id");
63 } catch(Exception e) {
64 }
65 subklass = new MetadataField(type.getAddressField("_subklass"), 0);
66 nextSibling = new MetadataField(type.getAddressField("_next_sibling"), 0);
67 nextLink = new MetadataField(type.getAddressField("_next_link"), 0);
68 vtableLen = new CIntField(type.getCIntegerField("_vtable_len"), 0);
69 classLoaderData = type.getAddressField("_class_loader_data");
70
71 LH_INSTANCE_SLOW_PATH_BIT = db.lookupIntConstant("Klass::_lh_instance_slow_path_bit").intValue();
72 LH_LOG2_ELEMENT_SIZE_SHIFT = db.lookupIntConstant("Klass::_lh_log2_element_size_shift").intValue();
73 LH_ELEMENT_TYPE_SHIFT = db.lookupIntConstant("Klass::_lh_element_type_shift").intValue();
74 LH_HEADER_SIZE_SHIFT = db.lookupIntConstant("Klass::_lh_header_size_shift").intValue();
75 LH_ARRAY_TAG_SHIFT = db.lookupIntConstant("Klass::_lh_array_tag_shift").intValue();
76 LH_ARRAY_TAG_TYPE_VALUE = db.lookupIntConstant("Klass::_lh_array_tag_type_value").intValue();
77 LH_ARRAY_TAG_OBJ_VALUE = db.lookupIntConstant("Klass::_lh_array_tag_obj_value").intValue();
78 }
79
80
81 public Klass(Address addr) {
82 super(addr);
83 }
84
85 // jvmdi support - see also class_status in VM code
86 public int getClassStatus() {
87 return 0; // overridden in derived classes
88 }
89
90 public boolean isKlass() { return true; }
91 public boolean isArrayKlass() { return false; }
92
93 // Fields
94 private static long javaMirrorFieldOffset;
95 private static MetadataField superField;
96 private static IntField layoutHelper;
97 private static AddressField name;
98 private static CIntField accessFlags;
99 private static MetadataField subklass;
100 private static MetadataField nextSibling;
101 private static MetadataField nextLink;
102 private static sun.jvm.hotspot.types.Field traceIDField;
103 private static CIntField vtableLen;
104 private static AddressField classLoaderData;
105
106 protected Symbol getSymbol(AddressField field) {
107 return Symbol.create(addr.getAddressAt(field.getOffset()));
108 }
109
110 // Accessors for declared fields
111 public Instance getJavaMirror() {
112 Address addr = getAddress().addOffsetTo(javaMirrorFieldOffset);
113 VMOopHandle vmOopHandle = VMObjectFactory.newObject(VMOopHandle.class, addr);
114 return vmOopHandle.resolve();
115 }
116 public Klass getSuper() { return (Klass) superField.getValue(this); }
117 public Klass getJavaSuper() { return null; }
118 public int getLayoutHelper() { return layoutHelper.getValue(this); }
119 public Symbol getName() { return getSymbol(name); }
120 public long getAccessFlags() { return accessFlags.getValue(this); }
121 // Convenience routine
122 public AccessFlags getAccessFlagsObj(){ return new AccessFlags(getAccessFlags()); }
123 public Klass getSubklassKlass() { return (Klass) subklass.getValue(this); }
124 public Klass getNextSiblingKlass() { return (Klass) nextSibling.getValue(this); }
125 public Klass getNextLinkKlass() { return (Klass) nextLink.getValue(this); }
126 public long getVtableLen() { return vtableLen.getValue(this); }
127
128 public ClassLoaderData getClassLoaderData() { return ClassLoaderData.instantiateWrapperFor(classLoaderData.getValue(getAddress())); }
129 public Oop getClassLoader() { return getClassLoaderData().getClassLoader(); }
130
131 public long traceID() {
132 if (traceIDField == null) return 0;
133 return traceIDField.getJLong(addr);
134 }
135
136 // subclass check
137 public boolean isSubclassOf(Klass k) {
138 if (k != null) {
139 Klass t = this;
140 // Run up the super chain and check
141 while (t != null) {
142 if (t.equals(k)) return true;
143 t = t.getSuper();
144 }
145 }
146 return false;
147 }
148
149 // subtype check
150 public boolean isSubtypeOf(Klass k) {
151 return computeSubtypeOf(k);
152 }
153
154 boolean computeSubtypeOf(Klass k) {
155 return isSubclassOf(k);
156 }
157
158 // Find LCA (Least Common Ancester) in class hierarchy
159 public Klass lca( Klass k2 ) {
160 Klass k1 = this;
161 while ( true ) {
162 if ( k1.isSubtypeOf(k2) ) return k2;
163 if ( k2.isSubtypeOf(k1) ) return k1;
164 k1 = k1.getSuper();
165 k2 = k2.getSuper();
166 }
167 }
168
169 public void printValueOn(PrintStream tty) {
170 tty.print("Klass");
171 }
172
173 public void iterateFields(MetadataVisitor visitor) {
174 // visitor.doOop(javaMirror, true);
175 visitor.doMetadata(superField, true);
176 visitor.doInt(layoutHelper, true);
177 // visitor.doOop(name, true);
178 visitor.doCInt(accessFlags, true);
179 visitor.doMetadata(subklass, true);
180 visitor.doMetadata(nextSibling, true);
181 visitor.doCInt(vtableLen, true);
182 }
183
184 public long getObjectSize() {
185 throw new RuntimeException("should not reach here");
186 }
187
188 /** Array class with specific rank */
189 public Klass arrayKlass(int rank) { return arrayKlassImpl(false, rank); }
190 /** Array class with this klass as element type */
191 public Klass arrayKlass() { return arrayKlassImpl(false); }
192 /** These will return null instead of allocating on the heap */
193 public Klass arrayKlassOrNull(int rank) { return arrayKlassImpl(true, rank); }
194 public Klass arrayKlassOrNull() { return arrayKlassImpl(true); }
195
196 public Klass arrayKlassImpl(boolean orNull, int rank) {
197 throw new RuntimeException("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
198 }
199
200 public Klass arrayKlassImpl(boolean orNull) {
201 throw new RuntimeException("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
202 }
203
204 // This returns the name in the form java/lang/String which isn't really a signature
205 // The subclasses override this to produce the correct form, eg
206 // Ljava/lang/String; For ArrayKlasses getName itself is the signature.
207 public String signature() { return getName().asString(); }
208
209 // Convenience routines
210 public boolean isPublic() { return getAccessFlagsObj().isPublic(); }
211 public boolean isFinal() { return getAccessFlagsObj().isFinal(); }
212 public boolean isInterface() { return getAccessFlagsObj().isInterface(); }
213 public boolean isAbstract() { return getAccessFlagsObj().isAbstract(); }
214 public boolean isSuper() { return getAccessFlagsObj().isSuper(); }
215 public boolean isSynthetic() { return getAccessFlagsObj().isSynthetic(); }
216 }