1 /*
2 * Copyright (c) 2000, 2019, 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
34 public class Klass extends Metadata implements ClassConstants {
35 static {
36 VM.registerVMInitializedObserver(new Observer() {
37 public void update(Observable o, Object data) {
38 initialize(VM.getVM().getTypeDataBase());
39 }
40 });
41 }
42
43 // anon-enum constants for _layout_helper.
44 public static int LH_INSTANCE_SLOW_PATH_BIT;
45 public static int LH_LOG2_ELEMENT_SIZE_SHIFT;
46 public static int LH_ELEMENT_TYPE_SHIFT;
47 public static int LH_HEADER_SIZE_SHIFT;
48 public static int LH_ARRAY_TAG_SHIFT;
49 public static int LH_ARRAY_TAG_TYPE_VALUE;
50 public static int LH_ARRAY_TAG_OBJ_VALUE;
51
52 private static synchronized void initialize(TypeDataBase db) throws WrongTypeException {
53 Type type = db.lookupType("Klass");
54 javaMirrorFieldOffset = type.getField("_java_mirror").getOffset();
55 superField = new MetadataField(type.getAddressField("_super"), 0);
56 layoutHelper = new IntField(type.getJIntField("_layout_helper"), 0);
57 name = type.getAddressField("_name");
58 accessFlags = new CIntField(type.getCIntegerField("_access_flags"), 0);
59 try {
60 traceIDField = type.getField("_trace_id");
61 } catch(Exception e) {
62 }
63 subklass = new MetadataField(type.getAddressField("_subklass"), 0);
64 nextSibling = new MetadataField(type.getAddressField("_next_sibling"), 0);
65 nextLink = new MetadataField(type.getAddressField("_next_link"), 0);
66 vtableLen = new CIntField(type.getCIntegerField("_vtable_len"), 0);
67 classLoaderData = type.getAddressField("_class_loader_data");
68
69 LH_INSTANCE_SLOW_PATH_BIT = db.lookupIntConstant("Klass::_lh_instance_slow_path_bit").intValue();
70 LH_LOG2_ELEMENT_SIZE_SHIFT = db.lookupIntConstant("Klass::_lh_log2_element_size_shift").intValue();
71 LH_ELEMENT_TYPE_SHIFT = db.lookupIntConstant("Klass::_lh_element_type_shift").intValue();
72 LH_HEADER_SIZE_SHIFT = db.lookupIntConstant("Klass::_lh_header_size_shift").intValue();
73 LH_ARRAY_TAG_SHIFT = db.lookupIntConstant("Klass::_lh_array_tag_shift").intValue();
74 LH_ARRAY_TAG_TYPE_VALUE = db.lookupIntConstant("Klass::_lh_array_tag_type_value").intValue();
75 LH_ARRAY_TAG_OBJ_VALUE = db.lookupIntConstant("Klass::_lh_array_tag_obj_value").intValue();
76 }
77
78
79 public Klass(Address addr) {
80 super(addr);
81 }
82
83 // jvmdi support - see also class_status in VM code
84 public int getClassStatus() {
85 return 0; // overridden in derived classes
86 }
87
88 public boolean isKlass() { return true; }
89 public boolean isArrayKlass() { return false; }
90
91 // Fields
92 private static long javaMirrorFieldOffset;
93 private static MetadataField superField;
94 private static IntField layoutHelper;
95 private static AddressField name;
96 private static CIntField accessFlags;
97 private static MetadataField subklass;
98 private static MetadataField nextSibling;
99 private static MetadataField nextLink;
100 private static sun.jvm.hotspot.types.Field traceIDField;
101 private static CIntField vtableLen;
102 private static AddressField classLoaderData;
103
104 protected Symbol getSymbol(AddressField field) {
105 return Symbol.create(addr.getAddressAt(field.getOffset()));
106 }
107
108 // Accessors for declared fields
109 public Instance getJavaMirror() {
110 Address addr = getAddress().addOffsetTo(javaMirrorFieldOffset);
111 VMOopHandle vmOopHandle = VMObjectFactory.newObject(VMOopHandle.class, addr);
112 return vmOopHandle.resolve();
113 }
114 public Klass getSuper() { return (Klass) superField.getValue(this); }
115 public Klass getJavaSuper() { return null; }
116 public int getLayoutHelper() { return (int) layoutHelper.getValue(this); }
117 public Symbol getName() { return getSymbol(name); }
118 public long getAccessFlags() { return accessFlags.getValue(this); }
119 // Convenience routine
120 public AccessFlags getAccessFlagsObj(){ return new AccessFlags(getAccessFlags()); }
121 public Klass getSubklassKlass() { return (Klass) subklass.getValue(this); }
122 public Klass getNextSiblingKlass() { return (Klass) nextSibling.getValue(this); }
123 public Klass getNextLinkKlass() { return (Klass) nextLink.getValue(this); }
124 public long getVtableLen() { return vtableLen.getValue(this); }
125
126 public ClassLoaderData getClassLoaderData() { return ClassLoaderData.instantiateWrapperFor(classLoaderData.getValue(getAddress())); }
127 public Oop getClassLoader() { return getClassLoaderData().getClassLoader(); }
128
129 public long traceID() {
130 if (traceIDField == null) return 0;
131 return traceIDField.getJLong(addr);
132 }
133
134 // computed access flags - takes care of inner classes etc.
135 // This is closer to actual source level than getAccessFlags() etc.
136 public long computeModifierFlags() {
137 return 0L; // Unless overridden, modifier_flags is 0.
138 }
139
140 // same as JVM_GetClassModifiers
141 public final long getClassModifiers() {
142 // unlike the VM counterpart we never have to deal with primitive type,
143 // because we operator on Klass and not an instance of java.lang.Class.
144 long flags = computeModifierFlags();
145 if (isSuper()) {
146 flags |= JVM_ACC_SUPER;
147 }
148 return flags;
149 }
150
151 // subclass check
152 public boolean isSubclassOf(Klass k) {
153 if (k != null) {
154 Klass t = this;
155 // Run up the super chain and check
156 while (t != null) {
157 if (t.equals(k)) return true;
158 t = t.getSuper();
159 }
160 }
161 return false;
162 }
163
164 // subtype check
165 public boolean isSubtypeOf(Klass k) {
166 return computeSubtypeOf(k);
167 }
168
169 boolean computeSubtypeOf(Klass k) {
170 return isSubclassOf(k);
171 }
172
173 // Find LCA (Least Common Ancester) in class heirarchy
174 public Klass lca( Klass k2 ) {
175 Klass k1 = this;
176 while ( true ) {
177 if ( k1.isSubtypeOf(k2) ) return k2;
178 if ( k2.isSubtypeOf(k1) ) return k1;
179 k1 = k1.getSuper();
180 k2 = k2.getSuper();
181 }
182 }
183
184 public void printValueOn(PrintStream tty) {
185 tty.print("Klass");
186 }
187
188 public void iterateFields(MetadataVisitor visitor) {
189 // visitor.doOop(javaMirror, true);
190 visitor.doMetadata(superField, true);
191 visitor.doInt(layoutHelper, true);
192 // visitor.doOop(name, true);
193 visitor.doCInt(accessFlags, true);
194 visitor.doMetadata(subklass, true);
195 visitor.doMetadata(nextSibling, true);
196 visitor.doCInt(vtableLen, true);
197 }
198
199 public long getObjectSize() {
200 throw new RuntimeException("should not reach here");
201 }
202
203 /** Array class with specific rank */
204 public Klass arrayKlass(int rank) { return arrayKlassImpl(false, rank); }
205 /** Array class with this klass as element type */
206 public Klass arrayKlass() { return arrayKlassImpl(false); }
207 /** These will return null instead of allocating on the heap */
208 public Klass arrayKlassOrNull(int rank) { return arrayKlassImpl(true, rank); }
209 public Klass arrayKlassOrNull() { return arrayKlassImpl(true); }
210
211 public Klass arrayKlassImpl(boolean orNull, int rank) {
212 throw new RuntimeException("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
213 }
214
215 public Klass arrayKlassImpl(boolean orNull) {
216 throw new RuntimeException("array_klass should be dispatched to InstanceKlass, ObjArrayKlass or TypeArrayKlass");
217 }
218
219 // This returns the name in the form java/lang/String which isn't really a signature
220 // The subclasses override this to produce the correct form, eg
221 // Ljava/lang/String; For ArrayKlasses getName itself is the signature.
222 public String signature() { return getName().asString(); }
223
224 // Convenience routines
225 public boolean isPublic() { return getAccessFlagsObj().isPublic(); }
226 public boolean isFinal() { return getAccessFlagsObj().isFinal(); }
227 public boolean isInterface() { return getAccessFlagsObj().isInterface(); }
228 public boolean isAbstract() { return getAccessFlagsObj().isAbstract(); }
229 public boolean isSuper() { return getAccessFlagsObj().isSuper(); }
230 public boolean isSynthetic() { return getAccessFlagsObj().isSynthetic(); }
231 public boolean hasFinalizer() { return getAccessFlagsObj().hasFinalizer(); }
232 public boolean isCloneable() { return getAccessFlagsObj().isCloneable(); }
233 public boolean hasVanillaConstructor() { return getAccessFlagsObj().hasVanillaConstructor(); }
234 public boolean hasMirandaMethods () { return getAccessFlagsObj().hasMirandaMethods(); }
235 }