1 /*
2 * Copyright (c) 2000, 2008, 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.util.*;
28
29 import sun.jvm.hotspot.debugger.*;
30 import sun.jvm.hotspot.memory.*;
31 import sun.jvm.hotspot.runtime.*;
32 import sun.jvm.hotspot.types.TypeDataBase;
33 import sun.jvm.hotspot.utilities.*;
34 import sun.jvm.hotspot.jdi.JVMTIThreadState;
35
36 /** A utility class encapsulating useful oop operations */
37
38 public class OopUtilities implements /* imports */ JVMTIThreadState {
39
40 // FIXME: access should be synchronized and cleared when VM is
41 // resumed
42 // String fields
43 private static IntField offsetField;
44 private static IntField countField;
45 private static OopField valueField;
46 // ThreadGroup fields
47 private static OopField threadGroupParentField;
48 private static OopField threadGroupNameField;
49 private static IntField threadGroupNThreadsField;
50 private static OopField threadGroupThreadsField;
51 private static IntField threadGroupNGroupsField;
52 private static OopField threadGroupGroupsField;
53 // Thread fields
54 private static OopField threadNameField;
55 private static OopField threadGroupField;
56 private static LongField threadEETopField;
57 // threadStatus field is new since 1.5
58 private static IntField threadStatusField;
59 // parkBlocker field is new since 1.6
60 private static OopField threadParkBlockerField;
61
62 // possible values of java_lang_Thread::ThreadStatus
63 private static int THREAD_STATUS_NEW;
64 /*
65 Other enum constants are not needed as of now. Uncomment these as and when needed.
66
67 private static int THREAD_STATUS_RUNNABLE;
68 private static int THREAD_STATUS_SLEEPING;
69 private static int THREAD_STATUS_IN_OBJECT_WAIT;
70 private static int THREAD_STATUS_IN_OBJECT_WAIT_TIMED;
71 private static int THREAD_STATUS_PARKED;
72 private static int THREAD_STATUS_PARKED_TIMED;
73 private static int THREAD_STATUS_BLOCKED_ON_MONITOR_ENTER;
74 private static int THREAD_STATUS_TERMINATED;
75 */
76
77 // java.lang.Class fields
78 private static OopField hcKlassField;
79
80 // java.util.concurrent.locks.AbstractOwnableSynchronizer fields
81 private static OopField absOwnSyncOwnerThreadField;
82
83 static {
84 VM.registerVMInitializedObserver(new Observer() {
85 public void update(Observable o, Object data) {
86 initialize(VM.getVM().getTypeDataBase());
87 }
88 });
89 }
90
91 private static synchronized void initialize(TypeDataBase db) {
92 // FIXME: don't need this observer; however, do need a VM resumed
93 // and suspended observer to refetch fields
94 }
95
96 public static String charArrayToString(TypeArray charArray) {
97 if (charArray == null) {
98 return null;
99 }
100 return charArrayToString(charArray, 0, (int) charArray.getLength());
101 }
102
103 public static String charArrayToString(TypeArray charArray, int offset, int length) {
104 if (charArray == null) {
105 return null;
106 }
107 final int limit = offset + length;
108 if (Assert.ASSERTS_ENABLED) {
109 Assert.that(offset >= 0 && limit <= charArray.getLength(), "out of bounds");
110 }
111 StringBuffer buf = new StringBuffer(length);
112 for (int i = offset; i < limit; i++) {
113 buf.append(charArray.getCharAt(i));
114 }
115 return buf.toString();
116 }
117
118 public static String stringOopToString(Oop stringOop) {
119 if (offsetField == null) {
120 InstanceKlass k = (InstanceKlass) stringOop.getKlass();
121 offsetField = (IntField) k.findField("offset", "I");
122 countField = (IntField) k.findField("count", "I");
123 valueField = (OopField) k.findField("value", "[C");
124 if (Assert.ASSERTS_ENABLED) {
125 Assert.that(offsetField != null &&
126 countField != null &&
127 valueField != null, "must find all java.lang.String fields");
128 }
129 }
130 return charArrayToString((TypeArray) valueField.getValue(stringOop),
131 offsetField.getValue(stringOop),
132 countField.getValue(stringOop));
133 }
134
135 private static void initThreadGroupFields() {
136 if (threadGroupParentField == null) {
137 SystemDictionary sysDict = VM.getVM().getSystemDictionary();
138 InstanceKlass k = sysDict.getThreadGroupKlass();
139 threadGroupParentField = (OopField) k.findField("parent", "Ljava/lang/ThreadGroup;");
140 threadGroupNameField = (OopField) k.findField("name", "Ljava/lang/String;");
141 threadGroupNThreadsField = (IntField) k.findField("nthreads", "I");
142 threadGroupThreadsField = (OopField) k.findField("threads", "[Ljava/lang/Thread;");
143 threadGroupNGroupsField = (IntField) k.findField("ngroups", "I");
144 threadGroupGroupsField = (OopField) k.findField("groups", "[Ljava/lang/ThreadGroup;");
145 if (Assert.ASSERTS_ENABLED) {
146 Assert.that(threadGroupParentField != null &&
147 threadGroupNameField != null &&
148 threadGroupNThreadsField != null &&
149 threadGroupThreadsField != null &&
150 threadGroupNGroupsField != null &&
151 threadGroupGroupsField != null, "must find all java.lang.ThreadGroup fields");
152 }
153 }
154 }
155
156 public static Oop threadGroupOopGetParent(Oop threadGroupOop) {
157 initThreadGroupFields();
158 return threadGroupParentField.getValue(threadGroupOop);
159 }
160
161 public static String threadGroupOopGetName(Oop threadGroupOop) {
162 initThreadGroupFields();
163 return stringOopToString(threadGroupNameField.getValue(threadGroupOop));
164 }
165
166 public static Oop[] threadGroupOopGetThreads(Oop threadGroupOop) {
167 initThreadGroupFields();
168 int nthreads = threadGroupNThreadsField.getValue(threadGroupOop);
169 Oop[] result = new Oop[nthreads];
170 ObjArray threads = (ObjArray) threadGroupThreadsField.getValue(threadGroupOop);
171 for (int i = 0; i < nthreads; i++) {
172 result[i] = threads.getObjAt(i);
173 }
174 return result;
175 }
176
177 public static Oop[] threadGroupOopGetGroups(Oop threadGroupOop) {
178 initThreadGroupFields();
179 int ngroups = threadGroupNGroupsField.getValue(threadGroupOop);
180 Oop[] result = new Oop[ngroups];
181 ObjArray groups = (ObjArray) threadGroupGroupsField.getValue(threadGroupOop);
182 for (int i = 0; i < ngroups; i++) {
183 result[i] = groups.getObjAt(i);
184 }
185 return result;
186 }
187
188 private static void initThreadFields() {
189 if (threadNameField == null) {
190 SystemDictionary sysDict = VM.getVM().getSystemDictionary();
191 InstanceKlass k = sysDict.getThreadKlass();
192 threadNameField = (OopField) k.findField("name", "[C");
193 threadGroupField = (OopField) k.findField("group", "Ljava/lang/ThreadGroup;");
194 threadEETopField = (LongField) k.findField("eetop", "J");
195 threadStatusField = (IntField) k.findField("threadStatus", "I");
196 threadParkBlockerField = (OopField) k.findField("parkBlocker",
197 "Ljava/lang/Object;");
198 TypeDataBase db = VM.getVM().getTypeDataBase();
199 THREAD_STATUS_NEW = db.lookupIntConstant("java_lang_Thread::NEW").intValue();
200 /*
201 Other enum constants are not needed as of now. Uncomment these as and when needed.
202
203 THREAD_STATUS_RUNNABLE = db.lookupIntConstant("java_lang_Thread::RUNNABLE").intValue();
204 THREAD_STATUS_SLEEPING = db.lookupIntConstant("java_lang_Thread::SLEEPING").intValue();
205 THREAD_STATUS_IN_OBJECT_WAIT = db.lookupIntConstant("java_lang_Thread::IN_OBJECT_WAIT").intValue();
206 THREAD_STATUS_IN_OBJECT_WAIT_TIMED = db.lookupIntConstant("java_lang_Thread::IN_OBJECT_WAIT_TIMED").intValue();
207 THREAD_STATUS_PARKED = db.lookupIntConstant("java_lang_Thread::PARKED").intValue();
208 THREAD_STATUS_PARKED_TIMED = db.lookupIntConstant("java_lang_Thread::PARKED_TIMED").intValue();
209 THREAD_STATUS_BLOCKED_ON_MONITOR_ENTER = db.lookupIntConstant("java_lang_Thread::BLOCKED_ON_MONITOR_ENTER").intValue();
210 THREAD_STATUS_TERMINATED = db.lookupIntConstant("java_lang_Thread::TERMINATED").intValue();
211 */
212
213 if (Assert.ASSERTS_ENABLED) {
214 // it is okay to miss threadStatusField, because this was
215 // introduced only in 1.5 JDK.
216 Assert.that(threadNameField != null &&
217 threadGroupField != null &&
218 threadEETopField != null, "must find all java.lang.Thread fields");
219 }
220 }
221 }
222
223 public static Oop threadOopGetThreadGroup(Oop threadOop) {
224 initThreadFields();
225 return threadGroupField.getValue(threadOop);
226 }
227
228 public static String threadOopGetName(Oop threadOop) {
229 initThreadFields();
230 return charArrayToString((TypeArray) threadNameField.getValue(threadOop));
231 }
232
233 /** May return null if, e.g., thread was not started */
234 public static JavaThread threadOopGetJavaThread(Oop threadOop) {
235 initThreadFields();
236 Address addr = threadOop.getHandle().getAddressAt(threadEETopField.getOffset());
237 if (addr == null) {
238 return null;
239 }
240 return VM.getVM().getThreads().createJavaThreadWrapper(addr);
241 }
242
243 /** returns value of java.lang.Thread.threadStatus field */
244 public static int threadOopGetThreadStatus(Oop threadOop) {
245 initThreadFields();
246 // The threadStatus is only present starting in 1.5
247 if (threadStatusField != null) {
248 return (int) threadStatusField.getValue(threadOop);
249 } else {
250 // All we can easily figure out is if it is alive, but that is
251 // enough info for a valid unknown status.
252 JavaThread thr = threadOopGetJavaThread(threadOop);
253 if (thr == null) {
254 // the thread hasn't run yet or is in the process of exiting
255 return THREAD_STATUS_NEW;
256 } else {
257 return JVMTI_THREAD_STATE_ALIVE;
258 }
259 }
260 }
261
262 /** returns value of java.lang.Thread.parkBlocker field */
263 public static Oop threadOopGetParkBlocker(Oop threadOop) {
264 initThreadFields();
265 if (threadParkBlockerField != null) {
266 return threadParkBlockerField.getValue(threadOop);
267 }
268 return null;
269 }
270
271 // initialize fields for java.lang.Class
272 private static void initClassFields() {
273 if (hcKlassField == null) {
274 // hc_klass is a HotSpot magic field and hence we can't
275 // find it from InstanceKlass for java.lang.Class.
276 TypeDataBase db = VM.getVM().getTypeDataBase();
277 int hcKlassOffset = (int) db.lookupType("java_lang_Class").getCIntegerField("klass_offset").getValue();
278 if (VM.getVM().isCompressedOopsEnabled()) {
279 hcKlassField = new NarrowOopField(new NamedFieldIdentifier("hc_klass"), hcKlassOffset, true);
280 } else {
281 hcKlassField = new OopField(new NamedFieldIdentifier("hc_klass"), hcKlassOffset, true);
282 }
283 }
284 }
285
286 /** get klassOop field at offset hc_klass_offset from a java.lang.Class object */
287 public static Klass classOopToKlass(Oop aClass) {
288 initClassFields();
289 return (Klass) hcKlassField.getValue(aClass);
290 }
291
292 // initialize fields for j.u.c.l AbstractOwnableSynchornizer class
293 private static void initAbsOwnSyncFields() {
294 if (absOwnSyncOwnerThreadField == null) {
295 SystemDictionary sysDict = VM.getVM().getSystemDictionary();
296 InstanceKlass k = sysDict.getAbstractOwnableSynchronizerKlass();
297 absOwnSyncOwnerThreadField =
298 (OopField) k.findField("exclusiveOwnerThread",
299 "Ljava/lang/Thread;");
300 }
301 }
302
303 // return exclusiveOwnerThread field of AbstractOwnableSynchronizer class
304 public static Oop abstractOwnableSynchronizerGetOwnerThread(Oop oop) {
305 initAbsOwnSyncFields();
306 if (absOwnSyncOwnerThreadField == null) {
307 return null; // pre-1.6 VM?
308 } else {
309 return absOwnSyncOwnerThreadField.getValue(oop);
310 }
311 }
312 }