1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)systemDictionary.cpp 1.367 08/01/17 09:41:11 JVM"
3 #endif
4 /*
5 * Copyright 1997-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_systemDictionary.cpp.incl"
30
31
32 Dictionary* SystemDictionary::_dictionary = NULL;
33 PlaceholderTable* SystemDictionary::_placeholders = NULL;
34 Dictionary* SystemDictionary::_shared_dictionary = NULL;
35 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
36 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
37
38
39 int SystemDictionary::_number_of_modifications = 0;
40
41 oop SystemDictionary::_system_loader_lock_obj = NULL;
42
43 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
44 = { NULL /*, NULL...*/ };
45
46 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
47
48 oop SystemDictionary::_java_system_loader = NULL;
49
50 bool SystemDictionary::_has_loadClassInternal = false;
51 bool SystemDictionary::_has_checkPackageAccess = false;
52
53 // lazily initialized klass variables
54 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
55
56
57 // ----------------------------------------------------------------------------
58 // Java-level SystemLoader
59
60 oop SystemDictionary::java_system_loader() {
61 return _java_system_loader;
62 }
63
64 void SystemDictionary::compute_java_system_loader(TRAPS) {
65 KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass));
66 JavaValue result(T_OBJECT);
67 JavaCalls::call_static(&result,
68 KlassHandle(THREAD, WK_KLASS(classloader_klass)),
69 vmSymbolHandles::getSystemClassLoader_name(),
70 vmSymbolHandles::void_classloader_signature(),
71 CHECK);
72
73 _java_system_loader = (oop)result.get_jobject();
74 }
75
76
77 // ----------------------------------------------------------------------------
78 // debugging
79
80 #ifdef ASSERT
81
82 // return true if class_name contains no '.' (internal format is '/')
83 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
84 if (class_name.not_null()) {
85 ResourceMark rm;
86 char* name = class_name->as_C_string();
87 return strchr(name, '.') == NULL;
88 } else {
89 return true;
90 }
91 }
92
93 #endif
94
95 // ----------------------------------------------------------------------------
96 // Resolving of classes
97
98 // Forwards to resolve_or_null
99
100 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
101 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
102 if (HAS_PENDING_EXCEPTION || klass == NULL) {
103 KlassHandle k_h(THREAD, klass);
104 // can return a null klass
105 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
106 }
107 return klass;
108 }
109
110 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
111 if (HAS_PENDING_EXCEPTION) {
112 // If we have a pending exception we forward it to the caller, unless throw_error is true,
113 // in which case we have to check whether the pending exception is a ClassNotFoundException,
114 // and if so convert it to a NoClassDefFoundError
115 // And chain the original ClassNotFoundException
116 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
117 ResourceMark rm(THREAD);
118 assert(klass_h() == NULL, "Should not have result with exception pending");
119 Handle e(THREAD, PENDING_EXCEPTION);
120 CLEAR_PENDING_EXCEPTION;
121 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
122 } else {
123 return NULL;
124 }
125 }
126 // Class not found, throw appropriate error or exception depending on value of throw_error
127 if (klass_h() == NULL) {
128 ResourceMark rm(THREAD);
129 if (throw_error) {
130 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
131 } else {
132 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
133 }
134 }
135 return (klassOop)klass_h();
136 }
137
138
139 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
140 bool throw_error, TRAPS)
141 {
142 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
143 }
144
145
146 // Forwards to resolve_instance_class_or_null
147
148 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
149 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
150 if (FieldType::is_array(class_name())) {
151 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
152 } else {
153 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
154 }
155 }
156
157 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
158 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
159 }
160
161 // Forwards to resolve_instance_class_or_null
162
163 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
164 Handle class_loader,
165 Handle protection_domain,
166 TRAPS) {
167 assert(FieldType::is_array(class_name()), "must be array");
168 jint dimension;
169 symbolOop object_key;
170 klassOop k = NULL;
171 // dimension and object_key are assigned as a side-effect of this call
172 BasicType t = FieldType::get_array_info(class_name(),
173 &dimension,
174 &object_key,
175 CHECK_NULL);
176
177 if (t == T_OBJECT) {
178 symbolHandle h_key(THREAD, object_key);
179 // naked oop "k" is OK here -- we assign back into it
180 k = SystemDictionary::resolve_instance_class_or_null(h_key,
181 class_loader,
182 protection_domain,
183 CHECK_NULL);
184 if (k != NULL) {
185 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
186 }
187 } else {
188 k = Universe::typeArrayKlassObj(t);
189 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
190 }
191 return k;
192 }
193
194
195 // Must be called for any super-class or super-interface resolution
196 // during class definition to allow class circularity checking
197 // super-interface callers:
198 // parse_interfaces - for defineClass & jvmtiRedefineClasses
199 // super-class callers:
200 // ClassFileParser - for defineClass & jvmtiRedefineClasses
201 // load_shared_class - while loading a class from shared archive
202 // resolve_instance_class_or_fail:
203 // when resolving a class that has an existing placeholder with
204 // a saved superclass [i.e. a defineClass is currently in progress]
205 // if another thread is trying to resolve the class, it must do
206 // super-class checks on its own thread to catch class circularity
207 // This last call is critical in class circularity checking for cases
208 // where classloading is delegated to different threads and the
209 // classloader lock is released.
210 // Take the case: Base->Super->Base
211 // 1. If thread T1 tries to do a defineClass of class Base
212 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
213 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
214 // so it tries to load Super
215 // 3. If we load the class internally, or user classloader uses same thread
216 // loadClassFromxxx or defineClass via parseClassFile Super ...
217 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
218 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
219 // 3.4 calls resolve_super_or_fail Base
220 // 3.5 finds T1,Base -> throws class circularity
221 //OR 4. If T2 tries to resolve Super via defineClass Super ...
222 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
223 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
224 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
225 // 4.4 finds T2, Super -> throws class circularity
226 // Must be called, even if superclass is null, since this is
227 // where the placeholder entry is created which claims this
228 // thread is loading this class/classloader.
229 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
230 symbolHandle class_name,
231 Handle class_loader,
232 Handle protection_domain,
233 bool is_superclass,
234 TRAPS) {
235
236 // Try to get one of the well-known klasses.
237 // They are trusted, and do not participate in circularities.
238 if (LinkWellKnownClasses) {
239 klassOop k = find_well_known_klass(class_name());
240 if (k != NULL) {
241 return k;
242 }
243 }
244
245 // Double-check, if child class is already loaded, just return super-class,interface
246 // Don't add a placedholder if already loaded, i.e. already in system dictionary
247 // Make sure there's a placeholder for the *child* before resolving.
248 // Used as a claim that this thread is currently loading superclass/classloader
249 // Used here for ClassCircularity checks and also for heap verification
250 // (every instanceKlass in the heap needs to be in the system dictionary
251 // or have a placeholder).
252 // Must check ClassCircularity before checking if super class is already loaded
253 //
254 // We might not already have a placeholder if this child_name was
255 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
256 // the name of the class might not be known until the stream is actually
257 // parsed.
258 // Bugs 4643874, 4715493
259 // compute_hash can have a safepoint
260
261 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
262 int d_index = dictionary()->hash_to_index(d_hash);
263 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
264 int p_index = placeholders()->hash_to_index(p_hash);
265 // can't throw error holding a lock
266 bool child_already_loaded = false;
267 bool throw_circularity_error = false;
268 {
269 MutexLocker mu(SystemDictionary_lock, THREAD);
270 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
271 klassOop quicksuperk;
272 // to support // loading: if child done loading, just return superclass
273 // if class_name, & class_loader don't match:
274 // if initial define, SD update will give LinkageError
275 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
276 // so we don't throw an exception here.
277 // see: nsk redefclass014 & java.lang.instrument Instrument032
278 if ((childk != NULL ) && (is_superclass) &&
279 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
280
281 ((Klass::cast(quicksuperk)->name() == class_name()) &&
282 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
283 return quicksuperk;
284 } else {
285 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
286 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
287 throw_circularity_error = true;
288 }
289
290 // add placeholder entry even if error - callers will remove on error
291 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
292 if (throw_circularity_error) {
293 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
294 }
295 }
296 }
297 if (throw_circularity_error) {
298 ResourceMark rm(THREAD);
299 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
300 }
301
302 // java.lang.Object should have been found above
303 assert(class_name() != NULL, "null super class for resolving");
304 // Resolve the super class or interface, check results on return
305 klassOop superk = NULL;
306 superk = SystemDictionary::resolve_or_null(class_name,
307 class_loader,
308 protection_domain,
309 THREAD);
310
311 KlassHandle superk_h(THREAD, superk);
312
313 // Note: clean up of placeholders currently in callers of
314 // resolve_super_or_fail - either at update_dictionary time
315 // or on error
316 {
317 MutexLocker mu(SystemDictionary_lock, THREAD);
318 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
319 if (probe != NULL) {
320 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
321 }
322 }
323 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
324 // can null superk
325 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
326 }
327
328 return superk_h();
329 }
330
331
332 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
333 Handle class_loader,
334 Handle protection_domain,
335 TRAPS) {
336 if(!has_checkPackageAccess()) return;
337
338 // Now we have to call back to java to check if the initating class has access
339 JavaValue result(T_VOID);
340 if (TraceProtectionDomainVerification) {
341 // Print out trace information
342 tty->print_cr("Checking package access");
343 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
344 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
345 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
346 }
347
348 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
349
350 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
351 JavaCalls::call_special(&result,
352 class_loader,
353 system_loader,
354 vmSymbolHandles::checkPackageAccess_name(),
355 vmSymbolHandles::class_protectiondomain_signature(),
356 Handle(THREAD, klass->java_mirror()),
357 protection_domain,
358 THREAD);
359
360 if (TraceProtectionDomainVerification) {
361 if (HAS_PENDING_EXCEPTION) {
362 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
363 } else {
364 tty->print_cr(" -> granted");
365 }
366 tty->cr();
367 }
368
369 if (HAS_PENDING_EXCEPTION) return;
370
371 // If no exception has been thrown, we have validated the protection domain
372 // Insert the protection domain of the initiating class into the set.
373 {
374 // We recalculate the entry here -- we've called out to java since
375 // the last time it was calculated.
376 symbolHandle kn(THREAD, klass->name());
377 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
378 int d_index = dictionary()->hash_to_index(d_hash);
379
380 MutexLocker mu(SystemDictionary_lock, THREAD);
381 {
382 // Note that we have an entry, and entries can be deleted only during GC,
383 // so we cannot allow GC to occur while we're holding this entry.
384
385 // We're using a No_Safepoint_Verifier to catch any place where we
386 // might potentially do a GC at all.
387 // SystemDictionary::do_unloading() asserts that classes are only
388 // unloaded at a safepoint.
389 No_Safepoint_Verifier nosafepoint;
390 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
391 protection_domain, THREAD);
392 }
393 }
394 }
395
396 // We only get here if this thread finds that another thread
397 // has already claimed the placeholder token for the current operation,
398 // but that other thread either never owned or gave up the
399 // object lock
400 // Waits on SystemDictionary_lock to indicate placeholder table updated
401 // On return, caller must recheck placeholder table state
402 //
403 // We only get here if
404 // 1) custom classLoader, i.e. not bootstrap classloader
405 // 2) UnsyncloadClass not set
406 // 3) custom classLoader has broken the class loader objectLock
407 // so another thread got here in parallel
408 //
409 // lockObject must be held.
410 // Complicated dance due to lock ordering:
411 // Must first release the classloader object lock to
412 // allow initial definer to complete the class definition
413 // and to avoid deadlock
414 // Reclaim classloader lock object with same original recursion count
415 // Must release SystemDictionary_lock after notify, since
416 // class loader lock must be claimed before SystemDictionary_lock
417 // to prevent deadlocks
418 //
419 // The notify allows applications that did an untimed wait() on
420 // the classloader object lock to not hang.
421 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
422 assert_lock_strong(SystemDictionary_lock);
423
424 bool calledholdinglock
425 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
426 assert(calledholdinglock,"must hold lock for notify");
427 assert(!UnsyncloadClass, "unexpected double_lock_wait");
428 ObjectSynchronizer::notifyall(lockObject, THREAD);
429 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
430 SystemDictionary_lock->wait();
431 SystemDictionary_lock->unlock();
432 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
433 SystemDictionary_lock->lock();
434 }
435
436 // If the class in is in the placeholder table, class loading is in progress
437 // For cases where the application changes threads to load classes, it
438 // is critical to ClassCircularity detection that we try loading
439 // the superclass on the same thread internally, so we do parallel
440 // super class loading here.
441 // This also is critical in cases where the original thread gets stalled
442 // even in non-circularity situations.
443 // Note: only one thread can define the class, but multiple can resolve
444 // Note: must call resolve_super_or_fail even if null super -
445 // to force placeholder entry creation for this class
446 // Caller must check for pending exception
447 // Returns non-null klassOop if other thread has completed load
448 // and we are done,
449 // If return null klassOop and no pending exception, the caller must load the class
450 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
451 symbolHandle name, symbolHandle superclassname, Handle class_loader,
452 Handle protection_domain, Handle lockObject, TRAPS) {
453
454 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
455 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
456 int d_index = dictionary()->hash_to_index(d_hash);
457 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
458 int p_index = placeholders()->hash_to_index(p_hash);
459
460 // superk is not used, resolve_super called for circularity check only
461 // This code is reached in two situations. One if this thread
462 // is loading the same class twice (e.g. ClassCircularity, or
463 // java.lang.instrument).
464 // The second is if another thread started the resolve_super first
465 // and has not yet finished.
466 // In both cases the original caller will clean up the placeholder
467 // entry on error.
468 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
469 superclassname,
470 class_loader,
471 protection_domain,
472 true,
473 CHECK_(nh));
474 // We don't redefine the class, so we just need to clean up if there
475 // was not an error (don't want to modify any system dictionary
476 // data structures).
477 {
478 MutexLocker mu(SystemDictionary_lock, THREAD);
479 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
480 SystemDictionary_lock->notify_all();
481 }
482
483 // UnsyncloadClass does NOT wait for parallel superclass loads to complete
484 // Bootstrap classloader does wait for parallel superclass loads
485 if (UnsyncloadClass) {
486 MutexLocker mu(SystemDictionary_lock, THREAD);
487 // Check if classloading completed while we were loading superclass or waiting
488 klassOop check = find_class(d_index, d_hash, name, class_loader);
489 if (check != NULL) {
490 // Klass is already loaded, so just return it
491 return(instanceKlassHandle(THREAD, check));
492 } else {
493 return nh;
494 }
495 }
496
497 // must loop to both handle other placeholder updates
498 // and spurious notifications
499 bool super_load_in_progress = true;
500 PlaceholderEntry* placeholder;
501 while (super_load_in_progress) {
502 MutexLocker mu(SystemDictionary_lock, THREAD);
503 // Check if classloading completed while we were loading superclass or waiting
504 klassOop check = find_class(d_index, d_hash, name, class_loader);
505 if (check != NULL) {
506 // Klass is already loaded, so just return it
507 return(instanceKlassHandle(THREAD, check));
508 } else {
509 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
510 if (placeholder && placeholder->super_load_in_progress() ){
511 // Before UnsyncloadClass:
512 // We only get here if the application has released the
513 // classloader lock when another thread was in the middle of loading a
514 // superclass/superinterface for this class, and now
515 // this thread is also trying to load this class.
516 // To minimize surprises, the first thread that started to
517 // load a class should be the one to complete the loading
518 // with the classfile it initially expected.
519 // This logic has the current thread wait once it has done
520 // all the superclass/superinterface loading it can, until
521 // the original thread completes the class loading or fails
522 // If it completes we will use the resulting instanceKlass
523 // which we will find below in the systemDictionary.
524 // We also get here for parallel bootstrap classloader
525 if (class_loader.is_null()) {
526 SystemDictionary_lock->wait();
527 } else {
528 double_lock_wait(lockObject, THREAD);
529 }
530 } else {
531 // If not in SD and not in PH, other thread's load must have failed
532 super_load_in_progress = false;
533 }
534 }
535 }
536 return (nh);
537 }
538
539
540 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
541 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
542 // First check to see if we should remove wrapping L and ;
543 symbolHandle name;
544 if (FieldType::is_obj(class_name())) {
545 ResourceMark rm(THREAD);
546 // Ignore wrapping L and ;.
547 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
548 } else {
549 name = class_name;
550 }
551
552 // UseNewReflection
553 // Fix for 4474172; see evaluation for more details
554 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
555
556 // Do lookup to see if class already exist and the protection domain
557 // has the right access
558 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
559 int d_index = dictionary()->hash_to_index(d_hash);
560 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
561 protection_domain, THREAD);
562 if (probe != NULL) return probe;
563
564
565 // Non-bootstrap class loaders will call out to class loader and
566 // define via jvm/jni_DefineClass which will acquire the
567 // class loader object lock to protect against multiple threads
568 // defining the class in parallel by accident.
569 // This lock must be acquired here so the waiter will find
570 // any successful result in the SystemDictionary and not attempt
571 // the define
572 // Classloaders that support parallelism, e.g. bootstrap classloader,
573 // or all classloaders with UnsyncloadClass do not acquire lock here
574 bool DoObjectLock = true;
575 if (UnsyncloadClass || (class_loader.is_null())) {
576 DoObjectLock = false;
577 }
578
579 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
580 int p_index = placeholders()->hash_to_index(p_hash);
581
582 // Class is not in SystemDictionary so we have to do loading.
583 // Make sure we are synchronized on the class loader before we proceed
584 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
585 check_loader_lock_contention(lockObject, THREAD);
586 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
587
588 // Check again (after locking) if class already exist in SystemDictionary
589 bool class_has_been_loaded = false;
590 bool super_load_in_progress = false;
591 bool havesupername = false;
592 instanceKlassHandle k;
593 PlaceholderEntry* placeholder;
594 symbolHandle superclassname;
595
596 {
597 MutexLocker mu(SystemDictionary_lock, THREAD);
598 klassOop check = find_class(d_index, d_hash, name, class_loader);
599 if (check != NULL) {
600 // Klass is already loaded, so just return it
601 class_has_been_loaded = true;
602 k = instanceKlassHandle(THREAD, check);
603 } else {
604 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
605 if (placeholder && placeholder->super_load_in_progress()) {
606 super_load_in_progress = true;
607 if (placeholder->havesupername() == true) {
608 superclassname = symbolHandle(THREAD, placeholder->supername());
609 havesupername = true;
610 }
611 }
612 }
613 }
614
615 // If the class in is in the placeholder table, class loading is in progress
616 if (super_load_in_progress && havesupername==true) {
617 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
618 class_loader, protection_domain, lockObject, THREAD);
619 if (HAS_PENDING_EXCEPTION) {
620 return NULL;
621 }
622 if (!k.is_null()) {
623 class_has_been_loaded = true;
624 }
625 }
626
627 if (!class_has_been_loaded) {
628
629 // add placeholder entry to record loading instance class
630 // Five cases:
631 // All cases need to prevent modifying bootclasssearchpath
632 // in parallel with a classload of same classname
633 // case 1. traditional classloaders that rely on the classloader object lock
634 // - no other need for LOAD_INSTANCE
635 // case 2. traditional classloaders that break the classloader object lock
636 // as a deadlock workaround. Detection of this case requires that
637 // this check is done while holding the classloader object lock,
638 // and that lock is still held when calling classloader's loadClass.
639 // For these classloaders, we ensure that the first requestor
640 // completes the load and other requestors wait for completion.
641 // case 3. UnsyncloadClass - don't use objectLocker
642 // With this flag, we allow parallel classloading of a
643 // class/classloader pair
644 // case4. Bootstrap classloader - don't own objectLocker
645 // This classloader supports parallelism at the classloader level,
646 // but only allows a single load of a class/classloader pair.
647 // No performance benefit and no deadlock issues.
648 // case 5. Future: parallel user level classloaders - without objectLocker
649 symbolHandle nullsymbolHandle;
650 bool throw_circularity_error = false;
651 {
652 MutexLocker mu(SystemDictionary_lock, THREAD);
653 if (!UnsyncloadClass) {
654 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
655 if (oldprobe) {
656 // only need check_seen_thread once, not on each loop
657 // 6341374 java/lang/Instrument with -Xcomp
658 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
659 throw_circularity_error = true;
660 } else {
661 // case 1: traditional: should never see load_in_progress.
662 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
663
664 // case 4: bootstrap classloader: prevent futile classloading,
665 // wait on first requestor
666 if (class_loader.is_null()) {
667 SystemDictionary_lock->wait();
668 } else {
669 // case 2: traditional with broken classloader lock. wait on first
670 // requestor.
671 double_lock_wait(lockObject, THREAD);
672 }
673 // Check if classloading completed while we were waiting
674 klassOop check = find_class(d_index, d_hash, name, class_loader);
675 if (check != NULL) {
676 // Klass is already loaded, so just return it
677 k = instanceKlassHandle(THREAD, check);
678 class_has_been_loaded = true;
679 }
680 // check if other thread failed to load and cleaned up
681 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
682 }
683 }
684 }
685 }
686 // All cases: add LOAD_INSTANCE
687 // case 3: UnsyncloadClass: allow competing threads to try
688 // LOAD_INSTANCE in parallel
689 // add placeholder entry even if error - callers will remove on error
690 if (!class_has_been_loaded) {
691 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
692 if (throw_circularity_error) {
693 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
694 }
695 // For class loaders that do not acquire the classloader object lock,
696 // if they did not catch another thread holding LOAD_INSTANCE,
697 // need a check analogous to the acquire ObjectLocker/find_class
698 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
699 // one final check if the load has already completed
700 klassOop check = find_class(d_index, d_hash, name, class_loader);
701 if (check != NULL) {
702 // Klass is already loaded, so just return it
703 k = instanceKlassHandle(THREAD, check);
704 class_has_been_loaded = true;
705 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
706 }
707 }
708 }
709 // must throw error outside of owning lock
710 if (throw_circularity_error) {
711 ResourceMark rm(THREAD);
712 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
713 }
714
715 if (!class_has_been_loaded) {
716
717 // Do actual loading
718 k = load_instance_class(name, class_loader, THREAD);
719
720 // In custom class loaders, the usual findClass calls
721 // findLoadedClass, which directly searches the SystemDictionary, then
722 // defineClass. If these are not atomic with respect to other threads,
723 // the findLoadedClass can fail, but the defineClass can get a
724 // LinkageError:: duplicate class definition.
725 // If they got a linkageError, check if a parallel class load succeeded.
726 // If it did, then for bytecode resolution the specification requires
727 // that we return the same result we did for the other thread, i.e. the
728 // successfully loaded instanceKlass
729 // Note: Class can not be unloaded as long as any classloader refs exist
730 // Should not get here for classloaders that support parallelism
731 // with the new cleaner mechanism, e.g. bootstrap classloader
732 if (UnsyncloadClass || (class_loader.is_null())) {
733 if (k.is_null() && HAS_PENDING_EXCEPTION
734 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
735 MutexLocker mu(SystemDictionary_lock, THREAD);
736 klassOop check = find_class(d_index, d_hash, name, class_loader);
737 if (check != NULL) {
738 // Klass is already loaded, so just use it
739 k = instanceKlassHandle(THREAD, check);
740 CLEAR_PENDING_EXCEPTION;
741 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
742 }
743 }
744 }
745
746 // clean up placeholder entries for success or error
747 // This cleans up LOAD_INSTANCE entries
748 // It also cleans up LOAD_SUPER entries on errors from
749 // calling load_instance_class
750 {
751 MutexLocker mu(SystemDictionary_lock, THREAD);
752 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
753 if (probe != NULL) {
754 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
755 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
756 SystemDictionary_lock->notify_all();
757 }
758 }
759
760 // If everything was OK (no exceptions, no null return value), and
761 // class_loader is NOT the defining loader, do a little more bookkeeping.
762 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
763 k->class_loader() != class_loader()) {
764
765 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
766
767 // Need to check for a PENDING_EXCEPTION again; check_constraints
768 // can throw and doesn't use the CHECK macro.
769 if (!HAS_PENDING_EXCEPTION) {
770 { // Grabbing the Compile_lock prevents systemDictionary updates
771 // during compilations.
772 MutexLocker mu(Compile_lock, THREAD);
773 update_dictionary(d_index, d_hash, p_index, p_hash,
774 k, class_loader, THREAD);
775 }
776 if (JvmtiExport::should_post_class_load()) {
777 Thread *thread = THREAD;
778 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
779 JvmtiExport::post_class_load((JavaThread *) thread, k());
780 }
781 }
782 }
783 if (HAS_PENDING_EXCEPTION || k.is_null()) {
784 // On error, clean up placeholders
785 {
786 MutexLocker mu(SystemDictionary_lock, THREAD);
787 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
788 SystemDictionary_lock->notify_all();
789 }
790 return NULL;
791 }
792 }
793 }
794
795 #ifdef ASSERT
796 {
797 Handle loader (THREAD, k->class_loader());
798 MutexLocker mu(SystemDictionary_lock, THREAD);
799 oop kk = find_class_or_placeholder(name, loader);
800 assert(kk == k(), "should be present in dictionary");
801 }
802 #endif
803
804 // return if the protection domain in NULL
805 if (protection_domain() == NULL) return k();
806
807 // Check the protection domain has the right access
808 {
809 MutexLocker mu(SystemDictionary_lock, THREAD);
810 // Note that we have an entry, and entries can be deleted only during GC,
811 // so we cannot allow GC to occur while we're holding this entry.
812 // We're using a No_Safepoint_Verifier to catch any place where we
813 // might potentially do a GC at all.
814 // SystemDictionary::do_unloading() asserts that classes are only
815 // unloaded at a safepoint.
816 No_Safepoint_Verifier nosafepoint;
817 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
818 class_loader,
819 protection_domain)) {
820 return k();
821 }
822 }
823
824 // Verify protection domain. If it fails an exception is thrown
825 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
826
827 return k();
828 }
829
830
831 // This routine does not lock the system dictionary.
832 //
833 // Since readers don't hold a lock, we must make sure that system
834 // dictionary entries are only removed at a safepoint (when only one
835 // thread is running), and are added to in a safe way (all links must
836 // be updated in an MT-safe manner).
837 //
838 // Callers should be aware that an entry could be added just after
839 // _dictionary->bucket(index) is read here, so the caller will not see
840 // the new entry.
841
842 klassOop SystemDictionary::find(symbolHandle class_name,
843 Handle class_loader,
844 Handle protection_domain,
845 TRAPS) {
846
847 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
848 int d_index = dictionary()->hash_to_index(d_hash);
849
850 {
851 // Note that we have an entry, and entries can be deleted only during GC,
852 // so we cannot allow GC to occur while we're holding this entry.
853 // We're using a No_Safepoint_Verifier to catch any place where we
854 // might potentially do a GC at all.
855 // SystemDictionary::do_unloading() asserts that classes are only
856 // unloaded at a safepoint.
857 No_Safepoint_Verifier nosafepoint;
858 return dictionary()->find(d_index, d_hash, class_name, class_loader,
859 protection_domain, THREAD);
860 }
861 }
862
863
864 // Look for a loaded instance or array klass by name. Do not do any loading.
865 // return NULL in case of error.
866 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
867 Handle class_loader,
868 Handle protection_domain,
869 TRAPS) {
870 klassOop k = NULL;
871 assert(class_name() != NULL, "class name must be non NULL");
872
873 // Try to get one of the well-known klasses.
874 if (LinkWellKnownClasses) {
875 k = find_well_known_klass(class_name());
876 if (k != NULL) {
877 return k;
878 }
879 }
880
881 if (FieldType::is_array(class_name())) {
882 // The name refers to an array. Parse the name.
883 jint dimension;
884 symbolOop object_key;
885
886 // dimension and object_key are assigned as a side-effect of this call
887 BasicType t = FieldType::get_array_info(class_name(), &dimension,
888 &object_key, CHECK_(NULL));
889 if (t != T_OBJECT) {
890 k = Universe::typeArrayKlassObj(t);
891 } else {
892 symbolHandle h_key(THREAD, object_key);
893 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
894 }
895 if (k != NULL) {
896 k = Klass::cast(k)->array_klass_or_null(dimension);
897 }
898 } else {
899 k = find(class_name, class_loader, protection_domain, THREAD);
900 }
901 return k;
902 }
903
904 // Quick range check for names of well-known classes:
905 static symbolOop wk_klass_name_limits[2] = {NULL, NULL};
906
907 #ifndef PRODUCT
908 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
909 // counts for "hello world": 3983, 1616, 1075
910 // => 60% hit after limit guard, 25% total win rate
911 #endif
912
913 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) {
914 // A bounds-check on class_name will quickly get a negative result.
915 NOT_PRODUCT(find_wkk_calls++);
916 if (class_name >= wk_klass_name_limits[0] &&
917 class_name <= wk_klass_name_limits[1]) {
918 NOT_PRODUCT(find_wkk_probes++);
919 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
920 if (sid != vmSymbols::NO_SID) {
921 klassOop k = NULL;
922 switch (sid) {
923 #define WK_KLASS_CASE(name, symbol, ignore_option) \
924 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
925 k = WK_KLASS(name); break;
926 WK_KLASSES_DO(WK_KLASS_CASE)
927 #undef WK_KLASS_CASE
928 }
929 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
930 return k;
931 }
932 }
933 return NULL;
934 }
935
936 // Note: this method is much like resolve_from_stream, but
937 // updates no supplemental data structures.
938 // TODO consolidate the two methods with a helper routine?
939 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
940 Handle class_loader,
941 Handle protection_domain,
942 ClassFileStream* st,
943 KlassHandle host_klass,
944 GrowableArray<Handle>* cp_patches,
945 TRAPS) {
946 symbolHandle parsed_name;
947
948 // Parse the stream. Note that we do this even though this klass might
949 // already be present in the SystemDictionary, otherwise we would not
950 // throw potential ClassFormatErrors.
951 //
952 // Note: "name" is updated.
953 // Further note: a placeholder will be added for this class when
954 // super classes are loaded (resolve_super_or_fail). We expect this
955 // to be called for all classes but java.lang.Object; and we preload
956 // java.lang.Object through resolve_or_fail, not this path.
957
958 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
959 class_loader,
960 protection_domain,
961 cp_patches,
962 parsed_name,
963 THREAD);
964
965 // We don't redefine the class, so we just need to clean up whether there
966 // was an error or not (don't want to modify any system dictionary
967 // data structures).
968 // Parsed name could be null if we threw an error before we got far
969 // enough along to parse it -- in that case, there is nothing to clean up.
970 if (!parsed_name.is_null()) {
971 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
972 class_loader);
973 int p_index = placeholders()->hash_to_index(p_hash);
974 {
975 MutexLocker mu(SystemDictionary_lock, THREAD);
976 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
977 SystemDictionary_lock->notify_all();
978 }
979 }
980
981 if (host_klass.not_null() && k.not_null()) {
982 assert(AnonymousClasses, "");
983 // If it's anonymous, initialize it now, since nobody else will.
984 k->set_host_klass(host_klass());
985
986 {
987 MutexLocker mu_r(Compile_lock, THREAD);
988
989 // Add to class hierarchy, initialize vtables, and do possible
990 // deoptimizations.
991 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
992
993 // But, do not add to system dictionary.
994 }
995
996 k->eager_initialize(THREAD);
997
998 // notify jvmti
999 if (JvmtiExport::should_post_class_load()) {
1000 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1001 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1002 }
1003 }
1004
1005 return k();
1006 }
1007
1008 // Add a klass to the system from a stream (called by jni_DefineClass and
1009 // JVM_DefineClass).
1010 // Note: class_name can be NULL. In that case we do not know the name of
1011 // the class until we have parsed the stream.
1012
1013 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
1014 Handle class_loader,
1015 Handle protection_domain,
1016 ClassFileStream* st,
1017 TRAPS) {
1018
1019 // Make sure we are synchronized on the class loader before we initiate
1020 // loading.
1021 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1022 check_loader_lock_contention(lockObject, THREAD);
1023 ObjectLocker ol(lockObject, THREAD);
1024
1025 symbolHandle parsed_name;
1026
1027 // Parse the stream. Note that we do this even though this klass might
1028 // already be present in the SystemDictionary, otherwise we would not
1029 // throw potential ClassFormatErrors.
1030 //
1031 // Note: "name" is updated.
1032 // Further note: a placeholder will be added for this class when
1033 // super classes are loaded (resolve_super_or_fail). We expect this
1034 // to be called for all classes but java.lang.Object; and we preload
1035 // java.lang.Object through resolve_or_fail, not this path.
1036
1037 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1038 class_loader,
1039 protection_domain,
1040 parsed_name,
1041 THREAD);
1042
1043 const char* pkg = "java/";
1044 if (!HAS_PENDING_EXCEPTION &&
1045 !class_loader.is_null() &&
1046 !parsed_name.is_null() &&
1047 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1048 // It is illegal to define classes in the "java." package from
1049 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1050 ResourceMark rm(THREAD);
1051 char* name = parsed_name->as_C_string();
1052 char* index = strrchr(name, '/');
1053 *index = '\0'; // chop to just the package name
1054 while ((index = strchr(name, '/')) != NULL) {
1055 *index = '.'; // replace '/' with '.' in package name
1056 }
1057 const char* fmt = "Prohibited package name: %s";
1058 size_t len = strlen(fmt) + strlen(name);
1059 char* message = NEW_RESOURCE_ARRAY(char, len);
1060 jio_snprintf(message, len, fmt, name);
1061 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1062 vmSymbols::java_lang_SecurityException(), message);
1063 }
1064
1065 if (!HAS_PENDING_EXCEPTION) {
1066 assert(!parsed_name.is_null(), "Sanity");
1067 assert(class_name.is_null() || class_name() == parsed_name(),
1068 "name mismatch");
1069 // Verification prevents us from creating names with dots in them, this
1070 // asserts that that's the case.
1071 assert(is_internal_format(parsed_name),
1072 "external class name format used internally");
1073
1074 // Add class just loaded
1075 define_instance_class(k, THREAD);
1076 }
1077
1078 // If parsing the class file or define_instance_class failed, we
1079 // need to remove the placeholder added on our behalf. But we
1080 // must make sure parsed_name is valid first (it won't be if we had
1081 // a format error before the class was parsed far enough to
1082 // find the name).
1083 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1084 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1085 class_loader);
1086 int p_index = placeholders()->hash_to_index(p_hash);
1087 {
1088 MutexLocker mu(SystemDictionary_lock, THREAD);
1089 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1090 SystemDictionary_lock->notify_all();
1091 }
1092 return NULL;
1093 }
1094
1095 // Make sure that we didn't leave a place holder in the
1096 // SystemDictionary; this is only done on success
1097 debug_only( {
1098 if (!HAS_PENDING_EXCEPTION) {
1099 assert(!parsed_name.is_null(), "parsed_name is still null?");
1100 symbolHandle h_name (THREAD, k->name());
1101 Handle h_loader (THREAD, k->class_loader());
1102
1103 MutexLocker mu(SystemDictionary_lock, THREAD);
1104
1105 oop check = find_class_or_placeholder(parsed_name, class_loader);
1106 assert(check == k(), "should be present in the dictionary");
1107
1108 oop check2 = find_class_or_placeholder(h_name, h_loader);
1109 assert(check == check2, "name inconsistancy in SystemDictionary");
1110 }
1111 } );
1112
1113 return k();
1114 }
1115
1116
1117 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1118 int number_of_entries) {
1119 assert(length == _nof_buckets * sizeof(HashtableBucket),
1120 "bad shared dictionary size.");
1121 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1122 }
1123
1124
1125 // If there is a shared dictionary, then find the entry for the
1126 // given shared system class, if any.
1127
1128 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1129 if (shared_dictionary() != NULL) {
1130 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1131 int d_index = dictionary()->hash_to_index(d_hash);
1132 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1133 } else {
1134 return NULL;
1135 }
1136 }
1137
1138
1139 // Load a class from the shared spaces (found through the shared system
1140 // dictionary). Force the superclass and all interfaces to be loaded.
1141 // Update the class definition to include sibling classes and no
1142 // subclasses (yet). [Classes in the shared space are not part of the
1143 // object hierarchy until loaded.]
1144
1145 instanceKlassHandle SystemDictionary::load_shared_class(
1146 symbolHandle class_name, Handle class_loader, TRAPS) {
1147 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1148 return load_shared_class(ik, class_loader, THREAD);
1149 }
1150
1151 // Note well! Changes to this method may affect oop access order
1152 // in the shared archive. Please take care to not make changes that
1153 // adversely affect cold start time by changing the oop access order
1154 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1155 // MarkAndMoveOrderedReadWrite closures.
1156 instanceKlassHandle SystemDictionary::load_shared_class(
1157 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1158 assert(class_loader.is_null(), "non-null classloader for shared class?");
1159 if (ik.not_null()) {
1160 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1161 symbolHandle class_name(THREAD, ik->name());
1162
1163 // Found the class, now load the superclass and interfaces. If they
1164 // are shared, add them to the main system dictionary and reset
1165 // their hierarchy references (supers, subs, and interfaces).
1166
1167 if (ik->super() != NULL) {
1168 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1169 resolve_super_or_fail(class_name, cn,
1170 class_loader, Handle(), true, CHECK_(nh));
1171 }
1172
1173 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1174 int num_interfaces = interfaces->length();
1175 for (int index = 0; index < num_interfaces; index++) {
1176 klassOop k = klassOop(interfaces->obj_at(index));
1177
1178 // Note: can not use instanceKlass::cast here because
1179 // interfaces' instanceKlass's C++ vtbls haven't been
1180 // reinitialized yet (they will be once the interface classes
1181 // are loaded)
1182 symbolHandle name (THREAD, k->klass_part()->name());
1183 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1184 }
1185
1186 // Adjust methods to recover missing data. They need addresses for
1187 // interpreter entry points and their default native method address
1188 // must be reset.
1189
1190 // Updating methods must be done under a lock so multiple
1191 // threads don't update these in parallel
1192 // Shared classes are all currently loaded by the bootstrap
1193 // classloader, so this will never cause a deadlock on
1194 // a custom class loader lock.
1195
1196 {
1197 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1198 check_loader_lock_contention(lockObject, THREAD);
1199 ObjectLocker ol(lockObject, THREAD, true);
1200
1201 objArrayHandle methods (THREAD, ik->methods());
1202 int num_methods = methods->length();
1203 for (int index2 = 0; index2 < num_methods; ++index2) {
1204 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1205 m()->link_method(m, CHECK_(nh));
1206 }
1207 }
1208
1209 if (TraceClassLoading) {
1210 ResourceMark rm;
1211 tty->print("[Loaded %s", ik->external_name());
1212 tty->print(" from shared objects file");
1213 tty->print_cr("]");
1214 }
1215 // notify a class loaded from shared object
1216 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1217 true /* shared class */);
1218 }
1219 return ik;
1220 }
1221
1222 #ifdef KERNEL
1223 // Some classes on the bootstrap class path haven't been installed on the
1224 // system yet. Call the DownloadManager method to make them appear in the
1225 // bootstrap class path and try again to load the named class.
1226 // Note that with delegation class loaders all classes in another loader will
1227 // first try to call this so it'd better be fast!!
1228 static instanceKlassHandle download_and_retry_class_load(
1229 symbolHandle class_name,
1230 TRAPS) {
1231
1232 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1233 instanceKlassHandle nk;
1234
1235 // If download manager class isn't loaded just return.
1236 if (dlm == NULL) return nk;
1237
1238 { HandleMark hm(THREAD);
1239 ResourceMark rm(THREAD);
1240 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1241 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1242
1243 // return value
1244 JavaValue result(T_OBJECT);
1245
1246 // Call the DownloadManager. We assume that it has a lock because
1247 // multiple classes could be not found and downloaded at the same time.
1248 // class sun.misc.DownloadManager;
1249 // public static String getBootClassPathEntryForClass(String className);
1250 JavaCalls::call_static(&result,
1251 KlassHandle(THREAD, dlm),
1252 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1253 vmSymbolHandles::string_string_signature(),
1254 class_string,
1255 CHECK_(nk));
1256
1257 // Get result.string and add to bootclasspath
1258 assert(result.get_type() == T_OBJECT, "just checking");
1259 oop obj = (oop) result.get_jobject();
1260 if (obj == NULL) { return nk; }
1261
1262 Handle h_obj(THREAD, obj);
1263 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1264 CHECK_(nk));
1265
1266 // lock the loader
1267 // we use this lock because JVMTI does.
1268 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1269
1270 ObjectLocker ol(loader_lock, THREAD);
1271 // add the file to the bootclasspath
1272 ClassLoader::update_class_path_entry_list(new_class_name, true);
1273 } // end HandleMark
1274
1275 if (TraceClassLoading) {
1276 ClassLoader::print_bootclasspath();
1277 }
1278 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1279 }
1280 #endif // KERNEL
1281
1282
1283 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1284 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1285 if (class_loader.is_null()) {
1286 // Search the shared system dictionary for classes preloaded into the
1287 // shared spaces.
1288 instanceKlassHandle k;
1289 k = load_shared_class(class_name, class_loader, THREAD);
1290
1291 if (k.is_null()) {
1292 // Use VM class loader
1293 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1294 }
1295
1296 #ifdef KERNEL
1297 // If the VM class loader has failed to load the class, call the
1298 // DownloadManager class to make it magically appear on the classpath
1299 // and try again. This is only configured with the Kernel VM.
1300 if (k.is_null()) {
1301 k = download_and_retry_class_load(class_name, CHECK_(nh));
1302 }
1303 #endif // KERNEL
1304
1305 // find_or_define_instance_class may return a different k
1306 if (!k.is_null()) {
1307 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1308 }
1309 return k;
1310 } else {
1311 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1312 ResourceMark rm(THREAD);
1313
1314 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1315 // Translate to external class name format, i.e., convert '/' chars to '.'
1316 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1317
1318 JavaValue result(T_OBJECT);
1319
1320 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1321
1322 // UnsyncloadClass option means don't synchronize loadClass() calls.
1323 // loadClassInternal() is synchronized and public loadClass(String) is not.
1324 // This flag is for diagnostic purposes only. It is risky to call
1325 // custom class loaders without synchronization.
1326 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1327 // findClass, this flag risks unexpected timing bugs in the field.
1328 // Do NOT assume this will be supported in future releases.
1329 if (!UnsyncloadClass && has_loadClassInternal()) {
1330 JavaCalls::call_special(&result,
1331 class_loader,
1332 spec_klass,
1333 vmSymbolHandles::loadClassInternal_name(),
1334 vmSymbolHandles::string_class_signature(),
1335 string,
1336 CHECK_(nh));
1337 } else {
1338 JavaCalls::call_virtual(&result,
1339 class_loader,
1340 spec_klass,
1341 vmSymbolHandles::loadClass_name(),
1342 vmSymbolHandles::string_class_signature(),
1343 string,
1344 CHECK_(nh));
1345 }
1346
1347 assert(result.get_type() == T_OBJECT, "just checking");
1348 oop obj = (oop) result.get_jobject();
1349
1350 // Primitive classes return null since forName() can not be
1351 // used to obtain any of the Class objects representing primitives or void
1352 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1353 instanceKlassHandle k =
1354 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1355 // For user defined Java class loaders, check that the name returned is
1356 // the same as that requested. This check is done for the bootstrap
1357 // loader when parsing the class file.
1358 if (class_name() == k->name()) {
1359 return k;
1360 }
1361 }
1362 // Class is not found or has the wrong name, return NULL
1363 return nh;
1364 }
1365 }
1366
1367 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1368
1369 Handle class_loader_h(THREAD, k->class_loader());
1370
1371 // for bootstrap classloader don't acquire lock
1372 if (!class_loader_h.is_null()) {
1373 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1374 compute_loader_lock_object(class_loader_h, THREAD)),
1375 "define called without lock");
1376 }
1377
1378
1379 // Check class-loading constraints. Throw exception if violation is detected.
1380 // Grabs and releases SystemDictionary_lock
1381 // The check_constraints/find_class call and update_dictionary sequence
1382 // must be "atomic" for a specific class/classloader pair so we never
1383 // define two different instanceKlasses for that class/classloader pair.
1384 // Existing classloaders will call define_instance_class with the
1385 // classloader lock held
1386 // Parallel classloaders will call find_or_define_instance_class
1387 // which will require a token to perform the define class
1388 symbolHandle name_h(THREAD, k->name());
1389 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1390 int d_index = dictionary()->hash_to_index(d_hash);
1391 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1392
1393 // Register class just loaded with class loader (placed in Vector)
1394 // Note we do this before updating the dictionary, as this can
1395 // fail with an OutOfMemoryError (if it does, we will *not* put this
1396 // class in the dictionary and will not update the class hierarchy).
1397 if (k->class_loader() != NULL) {
1398 methodHandle m(THREAD, Universe::loader_addClass_method());
1399 JavaValue result(T_VOID);
1400 JavaCallArguments args(class_loader_h);
1401 args.push_oop(Handle(THREAD, k->java_mirror()));
1402 JavaCalls::call(&result, m, &args, CHECK);
1403 }
1404
1405 // Add the new class. We need recompile lock during update of CHA.
1406 {
1407 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1408 int p_index = placeholders()->hash_to_index(p_hash);
1409
1410 MutexLocker mu_r(Compile_lock, THREAD);
1411
1412 // Add to class hierarchy, initialize vtables, and do possible
1413 // deoptimizations.
1414 add_to_hierarchy(k, CHECK); // No exception, but can block
1415
1416 // Add to systemDictionary - so other classes can see it.
1417 // Grabs and releases SystemDictionary_lock
1418 update_dictionary(d_index, d_hash, p_index, p_hash,
1419 k, class_loader_h, THREAD);
1420 }
1421 k->eager_initialize(THREAD);
1422
1423 // notify jvmti
1424 if (JvmtiExport::should_post_class_load()) {
1425 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1426 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1427
1428 }
1429 }
1430
1431 // Support parallel classloading
1432 // Initial implementation for bootstrap classloader
1433 // For future:
1434 // For custom class loaders that support parallel classloading,
1435 // in case they do not synchronize around
1436 // FindLoadedClass/DefineClass calls, we check for parallel
1437 // loading for them, wait if a defineClass is in progress
1438 // and return the initial requestor's results
1439 // For better performance, the class loaders should synchronize
1440 // findClass(), i.e. FindLoadedClass/DefineClass or they
1441 // potentially waste time reading and parsing the bytestream.
1442 // Note: VM callers should ensure consistency of k/class_name,class_loader
1443 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1444
1445 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1446
1447 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1448 int d_index = dictionary()->hash_to_index(d_hash);
1449
1450 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1451 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1452 int p_index = placeholders()->hash_to_index(p_hash);
1453 PlaceholderEntry* probe;
1454
1455 {
1456 MutexLocker mu(SystemDictionary_lock, THREAD);
1457 // First check if class already defined
1458 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1459 if (check != NULL) {
1460 return(instanceKlassHandle(THREAD, check));
1461 }
1462
1463 // Acquire define token for this class/classloader
1464 symbolHandle nullsymbolHandle;
1465 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1466 // Check if another thread defining in parallel
1467 if (probe->definer() == NULL) {
1468 // Thread will define the class
1469 probe->set_definer(THREAD);
1470 } else {
1471 // Wait for defining thread to finish and return results
1472 while (probe->definer() != NULL) {
1473 SystemDictionary_lock->wait();
1474 }
1475 if (probe->instanceKlass() != NULL) {
1476 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1477 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1478 } else {
1479 // If definer had an error, try again as any new thread would
1480 probe->set_definer(THREAD);
1481 #ifdef ASSERT
1482 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1483 assert(check == NULL, "definer missed recording success");
1484 #endif
1485 }
1486 }
1487 }
1488
1489 define_instance_class(k, THREAD);
1490
1491 Handle linkage_exception = Handle(); // null handle
1492
1493 // definer must notify any waiting threads
1494 {
1495 MutexLocker mu(SystemDictionary_lock, THREAD);
1496 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader);
1497 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1498 if (probe != NULL) {
1499 if (HAS_PENDING_EXCEPTION) {
1500 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1501 CLEAR_PENDING_EXCEPTION;
1502 } else {
1503 probe->set_instanceKlass(k());
1504 }
1505 probe->set_definer(NULL);
1506 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1507 SystemDictionary_lock->notify_all();
1508 }
1509 }
1510
1511 // Can't throw exception while holding lock due to rank ordering
1512 if (linkage_exception() != NULL) {
1513 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1514 }
1515
1516 return k;
1517 }
1518
1519 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1520 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1521 if (class_loader.is_null()) {
1522 return Handle(THREAD, _system_loader_lock_obj);
1523 } else {
1524 return class_loader;
1525 }
1526 }
1527
1528 // This method is added to check how often we have to wait to grab loader
1529 // lock. The results are being recorded in the performance counters defined in
1530 // ClassLoader::_sync_systemLoaderLockContentionRate and
1531 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1532 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1533 if (!UsePerfData) {
1534 return;
1535 }
1536
1537 assert(!loader_lock.is_null(), "NULL lock object");
1538
1539 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1540 == ObjectSynchronizer::owner_other) {
1541 // contention will likely happen, so increment the corresponding
1542 // contention counter.
1543 if (loader_lock() == _system_loader_lock_obj) {
1544 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1545 } else {
1546 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1547 }
1548 }
1549 }
1550
1551 // ----------------------------------------------------------------------------
1552 // Lookup
1553
1554 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1555 symbolHandle class_name,
1556 Handle class_loader) {
1557 assert_locked_or_safepoint(SystemDictionary_lock);
1558 assert (index == dictionary()->index_for(class_name, class_loader),
1559 "incorrect index?");
1560
1561 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1562 return k;
1563 }
1564
1565
1566 // Basic find on classes in the midst of being loaded
1567 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1568 symbolHandle class_name,
1569 Handle class_loader) {
1570 assert_locked_or_safepoint(SystemDictionary_lock);
1571
1572 return placeholders()->find_entry(index, hash, class_name, class_loader);
1573 }
1574
1575
1576 // Used for assertions and verification only
1577 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1578 Handle class_loader) {
1579 #ifndef ASSERT
1580 guarantee(VerifyBeforeGC ||
1581 VerifyDuringGC ||
1582 VerifyBeforeExit ||
1583 VerifyAfterGC, "too expensive");
1584 #endif
1585 assert_locked_or_safepoint(SystemDictionary_lock);
1586 symbolOop class_name_ = class_name();
1587 oop class_loader_ = class_loader();
1588
1589 // First look in the loaded class array
1590 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1591 int d_index = dictionary()->hash_to_index(d_hash);
1592 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1593
1594 if (lookup == NULL) {
1595 // Next try the placeholders
1596 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1597 int p_index = placeholders()->hash_to_index(p_hash);
1598 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1599 }
1600
1601 return lookup;
1602 }
1603
1604
1605 // Get the next class in the diictionary.
1606 klassOop SystemDictionary::try_get_next_class() {
1607 return dictionary()->try_get_next_class();
1608 }
1609
1610
1611 // ----------------------------------------------------------------------------
1612 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1613 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1614 // before a new class is used.
1615
1616 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1617 assert(k.not_null(), "just checking");
1618 // Link into hierachy. Make sure the vtables are initialized before linking into
1619 k->append_to_sibling_list(); // add to superklass/sibling list
1620 k->process_interfaces(THREAD); // handle all "implements" declarations
1621 k->set_init_state(instanceKlass::loaded);
1622 // Now flush all code that depended on old class hierarchy.
1623 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1624 // Also, first reinitialize vtable because it may have gotten out of synch
1625 // while the new class wasn't connected to the class hierarchy.
1626 Universe::flush_dependents_on(k);
1627 }
1628
1629
1630 // ----------------------------------------------------------------------------
1631 // GC support
1632
1633 // Following roots during mark-sweep is separated in two phases.
1634 //
1635 // The first phase follows preloaded classes and all other system
1636 // classes, since these will never get unloaded anyway.
1637 //
1638 // The second phase removes (unloads) unreachable classes from the
1639 // system dictionary and follows the remaining classes' contents.
1640
1641 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1642 // Follow preloaded classes/mirrors and system loader object
1643 blk->do_oop(&_java_system_loader);
1644 preloaded_oops_do(blk);
1645 always_strong_classes_do(blk);
1646 }
1647
1648
1649 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1650 // Follow all system classes and temporary placeholders in dictionary
1651 dictionary()->always_strong_classes_do(blk);
1652
1653 // Placeholders. These are *always* strong roots, as they
1654 // represent classes we're actively loading.
1655 placeholders_do(blk);
1656
1657 // Loader constraints. We must keep the symbolOop used in the name alive.
1658 constraints()->always_strong_classes_do(blk);
1659
1660 // Resolution errors keep the symbolOop for the error alive
1661 resolution_errors()->always_strong_classes_do(blk);
1662 }
1663
1664
1665 void SystemDictionary::placeholders_do(OopClosure* blk) {
1666 placeholders()->oops_do(blk);
1667 }
1668
1669
1670 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1671 bool result = dictionary()->do_unloading(is_alive);
1672 constraints()->purge_loader_constraints(is_alive);
1673 resolution_errors()->purge_resolution_errors(is_alive);
1674 return result;
1675 }
1676
1677
1678 // The mirrors are scanned by shared_oops_do() which is
1679 // not called by oops_do(). In order to process oops in
1680 // a necessary order, shared_oops_do() is call by
1681 // Universe::oops_do().
1682 void SystemDictionary::oops_do(OopClosure* f) {
1683 // Adjust preloaded classes and system loader object
1684 f->do_oop(&_java_system_loader);
1685 preloaded_oops_do(f);
1686
1687 lazily_loaded_oops_do(f);
1688
1689 // Adjust dictionary
1690 dictionary()->oops_do(f);
1691
1692 // Partially loaded classes
1693 placeholders()->oops_do(f);
1694
1695 // Adjust constraint table
1696 constraints()->oops_do(f);
1697
1698 // Adjust resolution error table
1699 resolution_errors()->oops_do(f);
1700 }
1701
1702
1703 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1704 f->do_oop((oop*) &wk_klass_name_limits[0]);
1705 f->do_oop((oop*) &wk_klass_name_limits[1]);
1706
1707 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1708 f->do_oop((oop*) &_well_known_klasses[k]);
1709 }
1710
1711 {
1712 for (int i = 0; i < T_VOID+1; i++) {
1713 if (_box_klasses[i] != NULL) {
1714 assert(i >= T_BOOLEAN, "checking");
1715 f->do_oop((oop*) &_box_klasses[i]);
1716 }
1717 }
1718 }
1719
1720 // The basic type mirrors would have already been processed in
1721 // Universe::oops_do(), via a call to shared_oops_do(), so should
1722 // not be processed again.
1723
1724 f->do_oop((oop*) &_system_loader_lock_obj);
1725 FilteredFieldsMap::klasses_oops_do(f);
1726 }
1727
1728 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1729 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1730 }
1731
1732 // Just the classes from defining class loaders
1733 // Don't iterate over placeholders
1734 void SystemDictionary::classes_do(void f(klassOop)) {
1735 dictionary()->classes_do(f);
1736 }
1737
1738 // Added for initialize_itable_for_klass
1739 // Just the classes from defining class loaders
1740 // Don't iterate over placeholders
1741 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1742 dictionary()->classes_do(f, CHECK);
1743 }
1744
1745 // All classes, and their class loaders
1746 // Don't iterate over placeholders
1747 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1748 dictionary()->classes_do(f);
1749 }
1750
1751 // All classes, and their class loaders
1752 // (added for helpers that use HandleMarks and ResourceMarks)
1753 // Don't iterate over placeholders
1754 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1755 dictionary()->classes_do(f, CHECK);
1756 }
1757
1758 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1759 placeholders()->entries_do(f);
1760 }
1761
1762 void SystemDictionary::methods_do(void f(methodOop)) {
1763 dictionary()->methods_do(f);
1764 }
1765
1766 // ----------------------------------------------------------------------------
1767 // Lazily load klasses
1768
1769 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1770 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1771
1772 // if multiple threads calling this function, only one thread will load
1773 // the class. The other threads will find the loaded version once the
1774 // class is loaded.
1775 klassOop aos = _abstract_ownable_synchronizer_klass;
1776 if (aos == NULL) {
1777 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1778 // Force a fence to prevent any read before the write completes
1779 OrderAccess::fence();
1780 _abstract_ownable_synchronizer_klass = k;
1781 }
1782 }
1783
1784 // ----------------------------------------------------------------------------
1785 // Initialization
1786
1787 void SystemDictionary::initialize(TRAPS) {
1788 // Allocate arrays
1789 assert(dictionary() == NULL,
1790 "SystemDictionary should only be initialized once");
1791 _dictionary = new Dictionary(_nof_buckets);
1792 _placeholders = new PlaceholderTable(_nof_buckets);
1793 _number_of_modifications = 0;
1794 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1795 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1796
1797 // Allocate private object used as system class loader lock
1798 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1799 // Initialize basic classes
1800 initialize_preloaded_classes(CHECK);
1801 }
1802
1803 // Compact table of directions on the initialization of klasses:
1804 static const short wk_init_info[] = {
1805 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1806 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1807 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1808 | (int)SystemDictionary::option ),
1809 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1810 #undef WK_KLASS_INIT_INFO
1811 0
1812 };
1813
1814 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1815 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1816 int info = wk_init_info[id - FIRST_WKID];
1817 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1818 symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid);
1819 klassOop* klassp = &_well_known_klasses[id];
1820 bool must_load = (init_opt < SystemDictionary::Opt);
1821 bool try_load = true;
1822 if (init_opt == SystemDictionary::Opt_Kernel) {
1823 #ifndef KERNEL
1824 try_load = false;
1825 #endif //KERNEL
1826 }
1827 if ((*klassp) == NULL && try_load) {
1828 if (must_load) {
1829 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1830 } else {
1831 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1832 }
1833 }
1834 return ((*klassp) != NULL);
1835 }
1836
1837 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1838 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1839 for (int id = (int)start_id; id < (int)limit_id; id++) {
1840 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1841 int info = wk_init_info[id - FIRST_WKID];
1842 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1843 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1844
1845 initialize_wk_klass((WKID)id, opt, CHECK);
1846
1847 // Update limits, so find_well_known_klass can be very fast:
1848 symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1849 if (wk_klass_name_limits[1] == NULL) {
1850 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1851 } else if (wk_klass_name_limits[1] < s) {
1852 wk_klass_name_limits[1] = s;
1853 } else if (wk_klass_name_limits[0] > s) {
1854 wk_klass_name_limits[0] = s;
1855 }
1856 }
1857 }
1858
1859
1860 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1861 assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once");
1862 // Preload commonly used klasses
1863 WKID scan = FIRST_WKID;
1864 // first do Object, String, Class
1865 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK);
1866
1867 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass)));
1868
1869 // Fixup mirrors for classes loaded before java.lang.Class.
1870 // These calls iterate over the objects currently in the perm gen
1871 // so calling them at this point is matters (not before when there
1872 // are fewer objects and not later after there are more objects
1873 // in the perm gen.
1874 Universe::initialize_basic_type_mirrors(CHECK);
1875 Universe::fixup_mirrors(CHECK);
1876
1877 // do a bunch more:
1878 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK);
1879
1880 // Preload ref klasses and set reference types
1881 instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER);
1882 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass));
1883
1884 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK);
1885 instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT);
1886 instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK);
1887 instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL);
1888 instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM);
1889
1890 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1891
1892 _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass);
1893 _box_klasses[T_CHAR] = WK_KLASS(char_klass);
1894 _box_klasses[T_FLOAT] = WK_KLASS(float_klass);
1895 _box_klasses[T_DOUBLE] = WK_KLASS(double_klass);
1896 _box_klasses[T_BYTE] = WK_KLASS(byte_klass);
1897 _box_klasses[T_SHORT] = WK_KLASS(short_klass);
1898 _box_klasses[T_INT] = WK_KLASS(int_klass);
1899 _box_klasses[T_LONG] = WK_KLASS(long_klass);
1900 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1901 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1902
1903 #ifdef KERNEL
1904 if (sun_jkernel_DownloadManager_klass() == NULL) {
1905 warning("Cannot find sun/jkernel/DownloadManager");
1906 }
1907 #endif // KERNEL
1908 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1909 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1910 _has_loadClassInternal = (method != NULL);
1911 }
1912
1913 { // Compute whether we should use checkPackageAccess or NOT
1914 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1915 _has_checkPackageAccess = (method != NULL);
1916 }
1917 }
1918
1919 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1920 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1921 BasicType SystemDictionary::box_klass_type(klassOop k) {
1922 assert(k != NULL, "");
1923 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1924 if (_box_klasses[i] == k)
1925 return (BasicType)i;
1926 }
1927 return T_OBJECT;
1928 }
1929
1930 // Constraints on class loaders. The details of the algorithm can be
1931 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1932 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1933 // that the system dictionary needs to maintain a set of contraints that
1934 // must be satisfied by all classes in the dictionary.
1935 // if defining is true, then LinkageError if already in systemDictionary
1936 // if initiating loader, then ok if instanceKlass matches existing entry
1937
1938 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1939 instanceKlassHandle k,
1940 Handle class_loader, bool defining,
1941 TRAPS) {
1942 const char *linkage_error = NULL;
1943 {
1944 symbolHandle name (THREAD, k->name());
1945 MutexLocker mu(SystemDictionary_lock, THREAD);
1946
1947 klassOop check = find_class(d_index, d_hash, name, class_loader);
1948 if (check != (klassOop)NULL) {
1949 // if different instanceKlass - duplicate class definition,
1950 // else - ok, class loaded by a different thread in parallel,
1951 // we should only have found it if it was done loading and ok to use
1952 // system dictionary only holds instance classes, placeholders
1953 // also holds array classes
1954
1955 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
1956 if ((defining == true) || (k() != check)) {
1957 linkage_error = "loader (instance of %s): attempted duplicate class "
1958 "definition for name: \"%s\"";
1959 } else {
1960 return;
1961 }
1962 }
1963
1964 #ifdef ASSERT
1965 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
1966 int p_index = placeholders()->hash_to_index(p_hash);
1967 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
1968 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
1969 #endif
1970
1971 if (linkage_error == NULL) {
1972 if (constraints()->check_or_update(k, class_loader, name) == false) {
1973 linkage_error = "loader constraint violation: loader (instance of %s)"
1974 " previously initiated loading for a different type with name \"%s\"";
1975 }
1976 }
1977 }
1978
1979 // Throw error now if needed (cannot throw while holding
1980 // SystemDictionary_lock because of rank ordering)
1981
1982 if (linkage_error) {
1983 ResourceMark rm(THREAD);
1984 const char* class_loader_name = loader_name(class_loader());
1985 char* type_name = k->name()->as_C_string();
1986 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1987 strlen(type_name);
1988 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1989 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1990 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1991 }
1992 }
1993
1994
1995 // Update system dictionary - done after check_constraint and add_to_hierachy
1996 // have been called.
1997 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1998 int p_index, unsigned int p_hash,
1999 instanceKlassHandle k,
2000 Handle class_loader,
2001 TRAPS) {
2002 // Compile_lock prevents systemDictionary updates during compilations
2003 assert_locked_or_safepoint(Compile_lock);
2004 symbolHandle name (THREAD, k->name());
2005
2006 {
2007 MutexLocker mu1(SystemDictionary_lock, THREAD);
2008
2009 // See whether biased locking is enabled and if so set it for this
2010 // klass.
2011 // Note that this must be done past the last potential blocking
2012 // point / safepoint. We enable biased locking lazily using a
2013 // VM_Operation to iterate the SystemDictionary and installing the
2014 // biasable mark word into each instanceKlass's prototype header.
2015 // To avoid race conditions where we accidentally miss enabling the
2016 // optimization for one class in the process of being added to the
2017 // dictionary, we must not safepoint after the test of
2018 // BiasedLocking::enabled().
2019 if (UseBiasedLocking && BiasedLocking::enabled()) {
2020 // Set biased locking bit for all loaded classes; it will be
2021 // cleared if revocation occurs too often for this type
2022 // NOTE that we must only do this when the class is initally
2023 // defined, not each time it is referenced from a new class loader
2024 if (k->class_loader() == class_loader()) {
2025 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2026 }
2027 }
2028
2029 // Check for a placeholder. If there, remove it and make a
2030 // new system dictionary entry.
2031 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2032 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2033 if (sd_check == NULL) {
2034 dictionary()->add_klass(name, class_loader, k);
2035 notice_modification();
2036 }
2037 #ifdef ASSERT
2038 sd_check = find_class(d_index, d_hash, name, class_loader);
2039 assert (sd_check != NULL, "should have entry in system dictionary");
2040 // Changed to allow PH to remain to complete class circularity checking
2041 // while only one thread can define a class at one time, multiple
2042 // classes can resolve the superclass for a class at one time,
2043 // and the placeholder is used to track that
2044 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2045 // assert (ph_check == NULL, "should not have a placeholder entry");
2046 #endif
2047 SystemDictionary_lock->notify_all();
2048 }
2049 }
2050
2051
2052 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2053 symbolHandle class_name, Handle class_loader, TRAPS) {
2054
2055 // First see if it has been loaded directly.
2056 // Force the protection domain to be null. (This removes protection checks.)
2057 Handle no_protection_domain;
2058 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2059 no_protection_domain, CHECK_NULL);
2060 if (klass != NULL)
2061 return klass;
2062
2063 // Now look to see if it has been loaded elsewhere, and is subject to
2064 // a loader constraint that would require this loader to return the
2065 // klass that is already loaded.
2066 if (FieldType::is_array(class_name())) {
2067 // Array classes are hard because their klassOops are not kept in the
2068 // constraint table. The array klass may be constrained, but the elem class
2069 // may not be.
2070 jint dimension;
2071 symbolOop object_key;
2072 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2073 &object_key, CHECK_(NULL));
2074 if (t != T_OBJECT) {
2075 klass = Universe::typeArrayKlassObj(t);
2076 } else {
2077 symbolHandle elem_name(THREAD, object_key);
2078 MutexLocker mu(SystemDictionary_lock, THREAD);
2079 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2080 }
2081 if (klass != NULL) {
2082 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2083 }
2084 } else {
2085 MutexLocker mu(SystemDictionary_lock, THREAD);
2086 // Non-array classes are easy: simply check the constraint table.
2087 klass = constraints()->find_constrained_klass(class_name, class_loader);
2088 }
2089
2090 return klass;
2091 }
2092
2093
2094 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2095 Handle class_loader1,
2096 Handle class_loader2,
2097 Thread* THREAD) {
2098 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2099 int d_index1 = dictionary()->hash_to_index(d_hash1);
2100
2101 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2102 int d_index2 = dictionary()->hash_to_index(d_hash2);
2103
2104 {
2105 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2106
2107 // Better never do a GC while we're holding these oops
2108 No_Safepoint_Verifier nosafepoint;
2109
2110 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2111 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2112 return constraints()->add_entry(class_name, klass1, class_loader1,
2113 klass2, class_loader2);
2114 }
2115 }
2116
2117 // Add entry to resolution error table to record the error when the first
2118 // attempt to resolve a reference to a class has failed.
2119 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2120 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2121 int index = resolution_errors()->hash_to_index(hash);
2122 {
2123 MutexLocker ml(SystemDictionary_lock, Thread::current());
2124 resolution_errors()->add_entry(index, hash, pool, which, error);
2125 }
2126 }
2127
2128 // Lookup resolution error table. Returns error if found, otherwise NULL.
2129 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2130 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2131 int index = resolution_errors()->hash_to_index(hash);
2132 {
2133 MutexLocker ml(SystemDictionary_lock, Thread::current());
2134 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2135 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2136 }
2137 }
2138
2139
2140 // Make sure all class components (including arrays) in the given
2141 // signature will be resolved to the same class in both loaders.
2142 // Returns the name of the type that failed a loader constraint check, or
2143 // NULL if no constraint failed. The returned C string needs cleaning up
2144 // with a ResourceMark in the caller
2145 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2146 Handle loader1, Handle loader2,
2147 bool is_method, TRAPS) {
2148 // Nothing to do if loaders are the same.
2149 if (loader1() == loader2()) {
2150 return NULL;
2151 }
2152
2153 SignatureStream sig_strm(signature, is_method);
2154 while (!sig_strm.is_done()) {
2155 if (sig_strm.is_object()) {
2156 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2157 symbolHandle sig (THREAD, s);
2158 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2159 return sig()->as_C_string();
2160 }
2161 }
2162 sig_strm.next();
2163 }
2164 return NULL;
2165 }
2166
2167
2168 // Since the identity hash code for symbols changes when the symbols are
2169 // moved from the regular perm gen (hash in the mark word) to the shared
2170 // spaces (hash is the address), the classes loaded into the dictionary
2171 // may be in the wrong buckets.
2172
2173 void SystemDictionary::reorder_dictionary() {
2174 dictionary()->reorder_dictionary();
2175 }
2176
2177
2178 void SystemDictionary::copy_buckets(char** top, char* end) {
2179 dictionary()->copy_buckets(top, end);
2180 }
2181
2182
2183 void SystemDictionary::copy_table(char** top, char* end) {
2184 dictionary()->copy_table(top, end);
2185 }
2186
2187
2188 void SystemDictionary::reverse() {
2189 dictionary()->reverse();
2190 }
2191
2192 int SystemDictionary::number_of_classes() {
2193 return dictionary()->number_of_entries();
2194 }
2195
2196
2197 // ----------------------------------------------------------------------------
2198 #ifndef PRODUCT
2199
2200 void SystemDictionary::print() {
2201 dictionary()->print();
2202
2203 // Placeholders
2204 GCMutexLocker mu(SystemDictionary_lock);
2205 placeholders()->print();
2206
2207 // loader constraints - print under SD_lock
2208 constraints()->print();
2209 }
2210
2211 #endif
2212
2213 void SystemDictionary::verify() {
2214 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2215 guarantee(constraints() != NULL,
2216 "Verify of loader constraints failed");
2217 guarantee(dictionary()->number_of_entries() >= 0 &&
2218 placeholders()->number_of_entries() >= 0,
2219 "Verify of system dictionary failed");
2220
2221 // Verify dictionary
2222 dictionary()->verify();
2223
2224 GCMutexLocker mu(SystemDictionary_lock);
2225 placeholders()->verify();
2226
2227 // Verify constraint table
2228 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2229 constraints()->verify(dictionary());
2230 }
2231
2232
2233 void SystemDictionary::verify_obj_klass_present(Handle obj,
2234 symbolHandle class_name,
2235 Handle class_loader) {
2236 GCMutexLocker mu(SystemDictionary_lock);
2237 oop probe = find_class_or_placeholder(class_name, class_loader);
2238 if (probe == NULL) {
2239 probe = SystemDictionary::find_shared_class(class_name);
2240 }
2241 guarantee(probe != NULL &&
2242 (!probe->is_klass() || probe == obj()),
2243 "Loaded klasses should be in SystemDictionary");
2244 }
2245
2246 #ifndef PRODUCT
2247
2248 // statistics code
2249 class ClassStatistics: AllStatic {
2250 private:
2251 static int nclasses; // number of classes
2252 static int nmethods; // number of methods
2253 static int nmethoddata; // number of methodData
2254 static int class_size; // size of class objects in words
2255 static int method_size; // size of method objects in words
2256 static int debug_size; // size of debug info in methods
2257 static int methoddata_size; // size of methodData objects in words
2258
2259 static void do_class(klassOop k) {
2260 nclasses++;
2261 class_size += k->size();
2262 if (k->klass_part()->oop_is_instance()) {
2263 instanceKlass* ik = (instanceKlass*)k->klass_part();
2264 class_size += ik->methods()->size();
2265 class_size += ik->constants()->size();
2266 class_size += ik->local_interfaces()->size();
2267 class_size += ik->transitive_interfaces()->size();
2268 // We do not have to count implementors, since we only store one!
2269 class_size += ik->fields()->size();
2270 }
2271 }
2272
2273 static void do_method(methodOop m) {
2274 nmethods++;
2275 method_size += m->size();
2276 // class loader uses same objArray for empty vectors, so don't count these
2277 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2278 if (m->has_stackmap_table()) {
2279 method_size += m->stackmap_data()->size();
2280 }
2281
2282 methodDataOop mdo = m->method_data();
2283 if (mdo != NULL) {
2284 nmethoddata++;
2285 methoddata_size += mdo->size();
2286 }
2287 }
2288
2289 public:
2290 static void print() {
2291 SystemDictionary::classes_do(do_class);
2292 SystemDictionary::methods_do(do_method);
2293 tty->print_cr("Class statistics:");
2294 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2295 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2296 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2297 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2298 }
2299 };
2300
2301
2302 int ClassStatistics::nclasses = 0;
2303 int ClassStatistics::nmethods = 0;
2304 int ClassStatistics::nmethoddata = 0;
2305 int ClassStatistics::class_size = 0;
2306 int ClassStatistics::method_size = 0;
2307 int ClassStatistics::debug_size = 0;
2308 int ClassStatistics::methoddata_size = 0;
2309
2310 void SystemDictionary::print_class_statistics() {
2311 ResourceMark rm;
2312 ClassStatistics::print();
2313 }
2314
2315
2316 class MethodStatistics: AllStatic {
2317 public:
2318 enum {
2319 max_parameter_size = 10
2320 };
2321 private:
2322
2323 static int _number_of_methods;
2324 static int _number_of_final_methods;
2325 static int _number_of_static_methods;
2326 static int _number_of_native_methods;
2327 static int _number_of_synchronized_methods;
2328 static int _number_of_profiled_methods;
2329 static int _number_of_bytecodes;
2330 static int _parameter_size_profile[max_parameter_size];
2331 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2332
2333 static void initialize() {
2334 _number_of_methods = 0;
2335 _number_of_final_methods = 0;
2336 _number_of_static_methods = 0;
2337 _number_of_native_methods = 0;
2338 _number_of_synchronized_methods = 0;
2339 _number_of_profiled_methods = 0;
2340 _number_of_bytecodes = 0;
2341 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2342 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2343 };
2344
2345 static void do_method(methodOop m) {
2346 _number_of_methods++;
2347 // collect flag info
2348 if (m->is_final() ) _number_of_final_methods++;
2349 if (m->is_static() ) _number_of_static_methods++;
2350 if (m->is_native() ) _number_of_native_methods++;
2351 if (m->is_synchronized()) _number_of_synchronized_methods++;
2352 if (m->method_data() != NULL) _number_of_profiled_methods++;
2353 // collect parameter size info (add one for receiver, if any)
2354 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2355 // collect bytecodes info
2356 {
2357 Thread *thread = Thread::current();
2358 HandleMark hm(thread);
2359 BytecodeStream s(methodHandle(thread, m));
2360 Bytecodes::Code c;
2361 while ((c = s.next()) >= 0) {
2362 _number_of_bytecodes++;
2363 _bytecodes_profile[c]++;
2364 }
2365 }
2366 }
2367
2368 public:
2369 static void print() {
2370 initialize();
2371 SystemDictionary::methods_do(do_method);
2372 // generate output
2373 tty->cr();
2374 tty->print_cr("Method statistics (static):");
2375 // flag distribution
2376 tty->cr();
2377 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2378 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2379 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2380 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2381 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2382 // parameter size profile
2383 tty->cr();
2384 { int tot = 0;
2385 int avg = 0;
2386 for (int i = 0; i < max_parameter_size; i++) {
2387 int n = _parameter_size_profile[i];
2388 tot += n;
2389 avg += n*i;
2390 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2391 }
2392 assert(tot == _number_of_methods, "should be the same");
2393 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2394 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2395 }
2396 // bytecodes profile
2397 tty->cr();
2398 { int tot = 0;
2399 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2400 if (Bytecodes::is_defined(i)) {
2401 Bytecodes::Code c = Bytecodes::cast(i);
2402 int n = _bytecodes_profile[c];
2403 tot += n;
2404 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2405 }
2406 }
2407 assert(tot == _number_of_bytecodes, "should be the same");
2408 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2409 }
2410 tty->cr();
2411 }
2412 };
2413
2414 int MethodStatistics::_number_of_methods;
2415 int MethodStatistics::_number_of_final_methods;
2416 int MethodStatistics::_number_of_static_methods;
2417 int MethodStatistics::_number_of_native_methods;
2418 int MethodStatistics::_number_of_synchronized_methods;
2419 int MethodStatistics::_number_of_profiled_methods;
2420 int MethodStatistics::_number_of_bytecodes;
2421 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2422 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2423
2424
2425 void SystemDictionary::print_method_statistics() {
2426 MethodStatistics::print();
2427 }
2428
2429 #endif // PRODUCT