1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_systemDictionary.cpp.incl"
27
28
29 Dictionary* SystemDictionary::_dictionary = NULL;
30 PlaceholderTable* SystemDictionary::_placeholders = NULL;
31 Dictionary* SystemDictionary::_shared_dictionary = NULL;
32 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
33 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
34
35
36 int SystemDictionary::_number_of_modifications = 0;
37
38 oop SystemDictionary::_system_loader_lock_obj = NULL;
39
40 klassOop SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
41 = { NULL /*, NULL...*/ };
42
43 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
44
45 oop SystemDictionary::_java_system_loader = NULL;
46
47 bool SystemDictionary::_has_loadClassInternal = false;
48 bool SystemDictionary::_has_checkPackageAccess = false;
49
50 // lazily initialized klass variables
51 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
52
53
54 // ----------------------------------------------------------------------------
55 // Java-level SystemLoader
56
57 oop SystemDictionary::java_system_loader() {
58 return _java_system_loader;
59 }
60
61 void SystemDictionary::compute_java_system_loader(TRAPS) {
62 KlassHandle system_klass(THREAD, WK_KLASS(classloader_klass));
63 JavaValue result(T_OBJECT);
64 JavaCalls::call_static(&result,
65 KlassHandle(THREAD, WK_KLASS(classloader_klass)),
66 vmSymbolHandles::getSystemClassLoader_name(),
67 vmSymbolHandles::void_classloader_signature(),
68 CHECK);
69
70 _java_system_loader = (oop)result.get_jobject();
71 }
72
73
74 // ----------------------------------------------------------------------------
75 // debugging
76
77 #ifdef ASSERT
78
79 // return true if class_name contains no '.' (internal format is '/')
80 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
81 if (class_name.not_null()) {
82 ResourceMark rm;
83 char* name = class_name->as_C_string();
84 return strchr(name, '.') == NULL;
85 } else {
86 return true;
87 }
88 }
89
90 #endif
91
92 // ----------------------------------------------------------------------------
93 // Resolving of classes
94
95 // Forwards to resolve_or_null
96
97 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
98 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
99 if (HAS_PENDING_EXCEPTION || klass == NULL) {
100 KlassHandle k_h(THREAD, klass);
101 // can return a null klass
102 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
103 }
104 return klass;
105 }
106
107 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
108 if (HAS_PENDING_EXCEPTION) {
109 // If we have a pending exception we forward it to the caller, unless throw_error is true,
110 // in which case we have to check whether the pending exception is a ClassNotFoundException,
111 // and if so convert it to a NoClassDefFoundError
112 // And chain the original ClassNotFoundException
113 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
114 ResourceMark rm(THREAD);
115 assert(klass_h() == NULL, "Should not have result with exception pending");
116 Handle e(THREAD, PENDING_EXCEPTION);
117 CLEAR_PENDING_EXCEPTION;
118 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
119 } else {
120 return NULL;
121 }
122 }
123 // Class not found, throw appropriate error or exception depending on value of throw_error
124 if (klass_h() == NULL) {
125 ResourceMark rm(THREAD);
126 if (throw_error) {
127 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
128 } else {
129 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
130 }
131 }
132 return (klassOop)klass_h();
133 }
134
135
136 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
137 bool throw_error, TRAPS)
138 {
139 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
140 }
141
142
143 // Forwards to resolve_instance_class_or_null
144
145 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
146 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
147 if (FieldType::is_array(class_name())) {
148 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
149 } else {
150 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
151 }
152 }
153
154 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
155 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
156 }
157
158 // Forwards to resolve_instance_class_or_null
159
160 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
161 Handle class_loader,
162 Handle protection_domain,
163 TRAPS) {
164 assert(FieldType::is_array(class_name()), "must be array");
165 jint dimension;
166 symbolOop object_key;
167 klassOop k = NULL;
168 // dimension and object_key are assigned as a side-effect of this call
169 BasicType t = FieldType::get_array_info(class_name(),
170 &dimension,
171 &object_key,
172 CHECK_NULL);
173
174 if (t == T_OBJECT) {
175 symbolHandle h_key(THREAD, object_key);
176 // naked oop "k" is OK here -- we assign back into it
177 k = SystemDictionary::resolve_instance_class_or_null(h_key,
178 class_loader,
179 protection_domain,
180 CHECK_NULL);
181 if (k != NULL) {
182 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
183 }
184 } else {
185 k = Universe::typeArrayKlassObj(t);
186 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
187 }
188 return k;
189 }
190
191
192 // Must be called for any super-class or super-interface resolution
193 // during class definition to allow class circularity checking
194 // super-interface callers:
195 // parse_interfaces - for defineClass & jvmtiRedefineClasses
196 // super-class callers:
197 // ClassFileParser - for defineClass & jvmtiRedefineClasses
198 // load_shared_class - while loading a class from shared archive
199 // resolve_instance_class_or_fail:
200 // when resolving a class that has an existing placeholder with
201 // a saved superclass [i.e. a defineClass is currently in progress]
202 // if another thread is trying to resolve the class, it must do
203 // super-class checks on its own thread to catch class circularity
204 // This last call is critical in class circularity checking for cases
205 // where classloading is delegated to different threads and the
206 // classloader lock is released.
207 // Take the case: Base->Super->Base
208 // 1. If thread T1 tries to do a defineClass of class Base
209 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
210 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
211 // so it tries to load Super
212 // 3. If we load the class internally, or user classloader uses same thread
213 // loadClassFromxxx or defineClass via parseClassFile Super ...
214 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
215 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
216 // 3.4 calls resolve_super_or_fail Base
217 // 3.5 finds T1,Base -> throws class circularity
218 //OR 4. If T2 tries to resolve Super via defineClass Super ...
219 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
220 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
221 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
222 // 4.4 finds T2, Super -> throws class circularity
223 // Must be called, even if superclass is null, since this is
224 // where the placeholder entry is created which claims this
225 // thread is loading this class/classloader.
226 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
227 symbolHandle class_name,
228 Handle class_loader,
229 Handle protection_domain,
230 bool is_superclass,
231 TRAPS) {
232
233 // Try to get one of the well-known klasses.
234 // They are trusted, and do not participate in circularities.
235 { klassOop k = find_well_known_klass(class_name());
236 if (k != NULL) {
237 return k;
238 }
239 }
240
241 // Double-check, if child class is already loaded, just return super-class,interface
242 // Don't add a placedholder if already loaded, i.e. already in system dictionary
243 // Make sure there's a placeholder for the *child* before resolving.
244 // Used as a claim that this thread is currently loading superclass/classloader
245 // Used here for ClassCircularity checks and also for heap verification
246 // (every instanceKlass in the heap needs to be in the system dictionary
247 // or have a placeholder).
248 // Must check ClassCircularity before checking if super class is already loaded
249 //
250 // We might not already have a placeholder if this child_name was
251 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
252 // the name of the class might not be known until the stream is actually
253 // parsed.
254 // Bugs 4643874, 4715493
255 // compute_hash can have a safepoint
256
257 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
258 int d_index = dictionary()->hash_to_index(d_hash);
259 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
260 int p_index = placeholders()->hash_to_index(p_hash);
261 // can't throw error holding a lock
262 bool child_already_loaded = false;
263 bool throw_circularity_error = false;
264 {
265 MutexLocker mu(SystemDictionary_lock, THREAD);
266 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
267 klassOop quicksuperk;
268 // to support // loading: if child done loading, just return superclass
269 // if class_name, & class_loader don't match:
270 // if initial define, SD update will give LinkageError
271 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
272 // so we don't throw an exception here.
273 // see: nsk redefclass014 & java.lang.instrument Instrument032
274 if ((childk != NULL ) && (is_superclass) &&
275 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
276
277 ((Klass::cast(quicksuperk)->name() == class_name()) &&
278 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
279 return quicksuperk;
280 } else {
281 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
282 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
283 throw_circularity_error = true;
284 }
285
286 // add placeholder entry even if error - callers will remove on error
287 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
288 if (throw_circularity_error) {
289 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
290 }
291 }
292 }
293 if (throw_circularity_error) {
294 ResourceMark rm(THREAD);
295 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
296 }
297
298 // java.lang.Object should have been found above
299 assert(class_name() != NULL, "null super class for resolving");
300 // Resolve the super class or interface, check results on return
301 klassOop superk = NULL;
302 superk = SystemDictionary::resolve_or_null(class_name,
303 class_loader,
304 protection_domain,
305 THREAD);
306
307 KlassHandle superk_h(THREAD, superk);
308
309 // Note: clean up of placeholders currently in callers of
310 // resolve_super_or_fail - either at update_dictionary time
311 // or on error
312 {
313 MutexLocker mu(SystemDictionary_lock, THREAD);
314 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
315 if (probe != NULL) {
316 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
317 }
318 }
319 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
320 // can null superk
321 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
322 }
323
324 return superk_h();
325 }
326
327
328 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
329 Handle class_loader,
330 Handle protection_domain,
331 TRAPS) {
332 if(!has_checkPackageAccess()) return;
333
334 // Now we have to call back to java to check if the initating class has access
335 JavaValue result(T_VOID);
336 if (TraceProtectionDomainVerification) {
337 // Print out trace information
338 tty->print_cr("Checking package access");
339 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
340 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
341 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
342 }
343
344 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
345
346 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
347 JavaCalls::call_special(&result,
348 class_loader,
349 system_loader,
350 vmSymbolHandles::checkPackageAccess_name(),
351 vmSymbolHandles::class_protectiondomain_signature(),
352 Handle(THREAD, klass->java_mirror()),
353 protection_domain,
354 THREAD);
355
356 if (TraceProtectionDomainVerification) {
357 if (HAS_PENDING_EXCEPTION) {
358 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
359 } else {
360 tty->print_cr(" -> granted");
361 }
362 tty->cr();
363 }
364
365 if (HAS_PENDING_EXCEPTION) return;
366
367 // If no exception has been thrown, we have validated the protection domain
368 // Insert the protection domain of the initiating class into the set.
369 {
370 // We recalculate the entry here -- we've called out to java since
371 // the last time it was calculated.
372 symbolHandle kn(THREAD, klass->name());
373 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
374 int d_index = dictionary()->hash_to_index(d_hash);
375
376 MutexLocker mu(SystemDictionary_lock, THREAD);
377 {
378 // Note that we have an entry, and entries can be deleted only during GC,
379 // so we cannot allow GC to occur while we're holding this entry.
380
381 // We're using a No_Safepoint_Verifier to catch any place where we
382 // might potentially do a GC at all.
383 // SystemDictionary::do_unloading() asserts that classes are only
384 // unloaded at a safepoint.
385 No_Safepoint_Verifier nosafepoint;
386 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
387 protection_domain, THREAD);
388 }
389 }
390 }
391
392 // We only get here if this thread finds that another thread
393 // has already claimed the placeholder token for the current operation,
394 // but that other thread either never owned or gave up the
395 // object lock
396 // Waits on SystemDictionary_lock to indicate placeholder table updated
397 // On return, caller must recheck placeholder table state
398 //
399 // We only get here if
400 // 1) custom classLoader, i.e. not bootstrap classloader
401 // 2) UnsyncloadClass not set
402 // 3) custom classLoader has broken the class loader objectLock
403 // so another thread got here in parallel
404 //
405 // lockObject must be held.
406 // Complicated dance due to lock ordering:
407 // Must first release the classloader object lock to
408 // allow initial definer to complete the class definition
409 // and to avoid deadlock
410 // Reclaim classloader lock object with same original recursion count
411 // Must release SystemDictionary_lock after notify, since
412 // class loader lock must be claimed before SystemDictionary_lock
413 // to prevent deadlocks
414 //
415 // The notify allows applications that did an untimed wait() on
416 // the classloader object lock to not hang.
417 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
418 assert_lock_strong(SystemDictionary_lock);
419
420 bool calledholdinglock
421 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
422 assert(calledholdinglock,"must hold lock for notify");
423 assert(!UnsyncloadClass, "unexpected double_lock_wait");
424 ObjectSynchronizer::notifyall(lockObject, THREAD);
425 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
426 SystemDictionary_lock->wait();
427 SystemDictionary_lock->unlock();
428 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
429 SystemDictionary_lock->lock();
430 }
431
432 // If the class in is in the placeholder table, class loading is in progress
433 // For cases where the application changes threads to load classes, it
434 // is critical to ClassCircularity detection that we try loading
435 // the superclass on the same thread internally, so we do parallel
436 // super class loading here.
437 // This also is critical in cases where the original thread gets stalled
438 // even in non-circularity situations.
439 // Note: only one thread can define the class, but multiple can resolve
440 // Note: must call resolve_super_or_fail even if null super -
441 // to force placeholder entry creation for this class
442 // Caller must check for pending exception
443 // Returns non-null klassOop if other thread has completed load
444 // and we are done,
445 // If return null klassOop and no pending exception, the caller must load the class
446 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
447 symbolHandle name, symbolHandle superclassname, Handle class_loader,
448 Handle protection_domain, Handle lockObject, TRAPS) {
449
450 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
451 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
452 int d_index = dictionary()->hash_to_index(d_hash);
453 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
454 int p_index = placeholders()->hash_to_index(p_hash);
455
456 // superk is not used, resolve_super called for circularity check only
457 // This code is reached in two situations. One if this thread
458 // is loading the same class twice (e.g. ClassCircularity, or
459 // java.lang.instrument).
460 // The second is if another thread started the resolve_super first
461 // and has not yet finished.
462 // In both cases the original caller will clean up the placeholder
463 // entry on error.
464 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
465 superclassname,
466 class_loader,
467 protection_domain,
468 true,
469 CHECK_(nh));
470 // We don't redefine the class, so we just need to clean up if there
471 // was not an error (don't want to modify any system dictionary
472 // data structures).
473 {
474 MutexLocker mu(SystemDictionary_lock, THREAD);
475 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
476 SystemDictionary_lock->notify_all();
477 }
478
479 // UnsyncloadClass does NOT wait for parallel superclass loads to complete
480 // Bootstrap classloader does wait for parallel superclass loads
481 if (UnsyncloadClass) {
482 MutexLocker mu(SystemDictionary_lock, THREAD);
483 // Check if classloading completed while we were loading superclass or waiting
484 klassOop check = find_class(d_index, d_hash, name, class_loader);
485 if (check != NULL) {
486 // Klass is already loaded, so just return it
487 return(instanceKlassHandle(THREAD, check));
488 } else {
489 return nh;
490 }
491 }
492
493 // must loop to both handle other placeholder updates
494 // and spurious notifications
495 bool super_load_in_progress = true;
496 PlaceholderEntry* placeholder;
497 while (super_load_in_progress) {
498 MutexLocker mu(SystemDictionary_lock, THREAD);
499 // Check if classloading completed while we were loading superclass or waiting
500 klassOop check = find_class(d_index, d_hash, name, class_loader);
501 if (check != NULL) {
502 // Klass is already loaded, so just return it
503 return(instanceKlassHandle(THREAD, check));
504 } else {
505 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
506 if (placeholder && placeholder->super_load_in_progress() ){
507 // Before UnsyncloadClass:
508 // We only get here if the application has released the
509 // classloader lock when another thread was in the middle of loading a
510 // superclass/superinterface for this class, and now
511 // this thread is also trying to load this class.
512 // To minimize surprises, the first thread that started to
513 // load a class should be the one to complete the loading
514 // with the classfile it initially expected.
515 // This logic has the current thread wait once it has done
516 // all the superclass/superinterface loading it can, until
517 // the original thread completes the class loading or fails
518 // If it completes we will use the resulting instanceKlass
519 // which we will find below in the systemDictionary.
520 // We also get here for parallel bootstrap classloader
521 if (class_loader.is_null()) {
522 SystemDictionary_lock->wait();
523 } else {
524 double_lock_wait(lockObject, THREAD);
525 }
526 } else {
527 // If not in SD and not in PH, other thread's load must have failed
528 super_load_in_progress = false;
529 }
530 }
531 }
532 return (nh);
533 }
534
535
536 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
537 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
538 // First check to see if we should remove wrapping L and ;
539 symbolHandle name;
540 if (FieldType::is_obj(class_name())) {
541 ResourceMark rm(THREAD);
542 // Ignore wrapping L and ;.
543 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
544 } else {
545 name = class_name;
546 }
547
548 // UseNewReflection
549 // Fix for 4474172; see evaluation for more details
550 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
551
552 // Do lookup to see if class already exist and the protection domain
553 // has the right access
554 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
555 int d_index = dictionary()->hash_to_index(d_hash);
556 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
557 protection_domain, THREAD);
558 if (probe != NULL) return probe;
559
560
561 // Non-bootstrap class loaders will call out to class loader and
562 // define via jvm/jni_DefineClass which will acquire the
563 // class loader object lock to protect against multiple threads
564 // defining the class in parallel by accident.
565 // This lock must be acquired here so the waiter will find
566 // any successful result in the SystemDictionary and not attempt
567 // the define
568 // Classloaders that support parallelism, e.g. bootstrap classloader,
569 // or all classloaders with UnsyncloadClass do not acquire lock here
570 bool DoObjectLock = true;
571 if (UnsyncloadClass || (class_loader.is_null())) {
572 DoObjectLock = false;
573 }
574
575 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
576 int p_index = placeholders()->hash_to_index(p_hash);
577
578 // Class is not in SystemDictionary so we have to do loading.
579 // Make sure we are synchronized on the class loader before we proceed
580 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
581 check_loader_lock_contention(lockObject, THREAD);
582 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
583
584 // Check again (after locking) if class already exist in SystemDictionary
585 bool class_has_been_loaded = false;
586 bool super_load_in_progress = false;
587 bool havesupername = false;
588 instanceKlassHandle k;
589 PlaceholderEntry* placeholder;
590 symbolHandle superclassname;
591
592 {
593 MutexLocker mu(SystemDictionary_lock, THREAD);
594 klassOop check = find_class(d_index, d_hash, name, class_loader);
595 if (check != NULL) {
596 // Klass is already loaded, so just return it
597 class_has_been_loaded = true;
598 k = instanceKlassHandle(THREAD, check);
599 } else {
600 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
601 if (placeholder && placeholder->super_load_in_progress()) {
602 super_load_in_progress = true;
603 if (placeholder->havesupername() == true) {
604 superclassname = symbolHandle(THREAD, placeholder->supername());
605 havesupername = true;
606 }
607 }
608 }
609 }
610
611 // If the class in is in the placeholder table, class loading is in progress
612 if (super_load_in_progress && havesupername==true) {
613 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
614 class_loader, protection_domain, lockObject, THREAD);
615 if (HAS_PENDING_EXCEPTION) {
616 return NULL;
617 }
618 if (!k.is_null()) {
619 class_has_been_loaded = true;
620 }
621 }
622
623 if (!class_has_been_loaded) {
624
625 // add placeholder entry to record loading instance class
626 // Five cases:
627 // All cases need to prevent modifying bootclasssearchpath
628 // in parallel with a classload of same classname
629 // case 1. traditional classloaders that rely on the classloader object lock
630 // - no other need for LOAD_INSTANCE
631 // case 2. traditional classloaders that break the classloader object lock
632 // as a deadlock workaround. Detection of this case requires that
633 // this check is done while holding the classloader object lock,
634 // and that lock is still held when calling classloader's loadClass.
635 // For these classloaders, we ensure that the first requestor
636 // completes the load and other requestors wait for completion.
637 // case 3. UnsyncloadClass - don't use objectLocker
638 // With this flag, we allow parallel classloading of a
639 // class/classloader pair
640 // case4. Bootstrap classloader - don't own objectLocker
641 // This classloader supports parallelism at the classloader level,
642 // but only allows a single load of a class/classloader pair.
643 // No performance benefit and no deadlock issues.
644 // case 5. Future: parallel user level classloaders - without objectLocker
645 symbolHandle nullsymbolHandle;
646 bool throw_circularity_error = false;
647 {
648 MutexLocker mu(SystemDictionary_lock, THREAD);
649 if (!UnsyncloadClass) {
650 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
651 if (oldprobe) {
652 // only need check_seen_thread once, not on each loop
653 // 6341374 java/lang/Instrument with -Xcomp
654 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
655 throw_circularity_error = true;
656 } else {
657 // case 1: traditional: should never see load_in_progress.
658 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
659
660 // case 4: bootstrap classloader: prevent futile classloading,
661 // wait on first requestor
662 if (class_loader.is_null()) {
663 SystemDictionary_lock->wait();
664 } else {
665 // case 2: traditional with broken classloader lock. wait on first
666 // requestor.
667 double_lock_wait(lockObject, THREAD);
668 }
669 // Check if classloading completed while we were waiting
670 klassOop check = find_class(d_index, d_hash, name, class_loader);
671 if (check != NULL) {
672 // Klass is already loaded, so just return it
673 k = instanceKlassHandle(THREAD, check);
674 class_has_been_loaded = true;
675 }
676 // check if other thread failed to load and cleaned up
677 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
678 }
679 }
680 }
681 }
682 // All cases: add LOAD_INSTANCE
683 // case 3: UnsyncloadClass: allow competing threads to try
684 // LOAD_INSTANCE in parallel
685 // add placeholder entry even if error - callers will remove on error
686 if (!class_has_been_loaded) {
687 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
688 if (throw_circularity_error) {
689 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
690 }
691 // For class loaders that do not acquire the classloader object lock,
692 // if they did not catch another thread holding LOAD_INSTANCE,
693 // need a check analogous to the acquire ObjectLocker/find_class
694 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
695 // one final check if the load has already completed
696 klassOop check = find_class(d_index, d_hash, name, class_loader);
697 if (check != NULL) {
698 // Klass is already loaded, so just return it
699 k = instanceKlassHandle(THREAD, check);
700 class_has_been_loaded = true;
701 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
702 }
703 }
704 }
705 // must throw error outside of owning lock
706 if (throw_circularity_error) {
707 ResourceMark rm(THREAD);
708 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
709 }
710
711 if (!class_has_been_loaded) {
712
713 // Do actual loading
714 k = load_instance_class(name, class_loader, THREAD);
715
716 // In custom class loaders, the usual findClass calls
717 // findLoadedClass, which directly searches the SystemDictionary, then
718 // defineClass. If these are not atomic with respect to other threads,
719 // the findLoadedClass can fail, but the defineClass can get a
720 // LinkageError:: duplicate class definition.
721 // If they got a linkageError, check if a parallel class load succeeded.
722 // If it did, then for bytecode resolution the specification requires
723 // that we return the same result we did for the other thread, i.e. the
724 // successfully loaded instanceKlass
725 // Note: Class can not be unloaded as long as any classloader refs exist
726 // Should not get here for classloaders that support parallelism
727 // with the new cleaner mechanism, e.g. bootstrap classloader
728 if (UnsyncloadClass || (class_loader.is_null())) {
729 if (k.is_null() && HAS_PENDING_EXCEPTION
730 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
731 MutexLocker mu(SystemDictionary_lock, THREAD);
732 klassOop check = find_class(d_index, d_hash, name, class_loader);
733 if (check != NULL) {
734 // Klass is already loaded, so just use it
735 k = instanceKlassHandle(THREAD, check);
736 CLEAR_PENDING_EXCEPTION;
737 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
738 }
739 }
740 }
741
742 // clean up placeholder entries for success or error
743 // This cleans up LOAD_INSTANCE entries
744 // It also cleans up LOAD_SUPER entries on errors from
745 // calling load_instance_class
746 {
747 MutexLocker mu(SystemDictionary_lock, THREAD);
748 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
749 if (probe != NULL) {
750 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
751 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
752 SystemDictionary_lock->notify_all();
753 }
754 }
755
756 // If everything was OK (no exceptions, no null return value), and
757 // class_loader is NOT the defining loader, do a little more bookkeeping.
758 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
759 k->class_loader() != class_loader()) {
760
761 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
762
763 // Need to check for a PENDING_EXCEPTION again; check_constraints
764 // can throw and doesn't use the CHECK macro.
765 if (!HAS_PENDING_EXCEPTION) {
766 { // Grabbing the Compile_lock prevents systemDictionary updates
767 // during compilations.
768 MutexLocker mu(Compile_lock, THREAD);
769 update_dictionary(d_index, d_hash, p_index, p_hash,
770 k, class_loader, THREAD);
771 }
772 if (JvmtiExport::should_post_class_load()) {
773 Thread *thread = THREAD;
774 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
775 JvmtiExport::post_class_load((JavaThread *) thread, k());
776 }
777 }
778 }
779 if (HAS_PENDING_EXCEPTION || k.is_null()) {
780 // On error, clean up placeholders
781 {
782 MutexLocker mu(SystemDictionary_lock, THREAD);
783 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
784 SystemDictionary_lock->notify_all();
785 }
786 return NULL;
787 }
788 }
789 }
790
791 #ifdef ASSERT
792 {
793 Handle loader (THREAD, k->class_loader());
794 MutexLocker mu(SystemDictionary_lock, THREAD);
795 oop kk = find_class_or_placeholder(name, loader);
796 assert(kk == k(), "should be present in dictionary");
797 }
798 #endif
799
800 // return if the protection domain in NULL
801 if (protection_domain() == NULL) return k();
802
803 // Check the protection domain has the right access
804 {
805 MutexLocker mu(SystemDictionary_lock, THREAD);
806 // Note that we have an entry, and entries can be deleted only during GC,
807 // so we cannot allow GC to occur while we're holding this entry.
808 // We're using a No_Safepoint_Verifier to catch any place where we
809 // might potentially do a GC at all.
810 // SystemDictionary::do_unloading() asserts that classes are only
811 // unloaded at a safepoint.
812 No_Safepoint_Verifier nosafepoint;
813 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
814 class_loader,
815 protection_domain)) {
816 return k();
817 }
818 }
819
820 // Verify protection domain. If it fails an exception is thrown
821 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
822
823 return k();
824 }
825
826
827 // This routine does not lock the system dictionary.
828 //
829 // Since readers don't hold a lock, we must make sure that system
830 // dictionary entries are only removed at a safepoint (when only one
831 // thread is running), and are added to in a safe way (all links must
832 // be updated in an MT-safe manner).
833 //
834 // Callers should be aware that an entry could be added just after
835 // _dictionary->bucket(index) is read here, so the caller will not see
836 // the new entry.
837
838 klassOop SystemDictionary::find(symbolHandle class_name,
839 Handle class_loader,
840 Handle protection_domain,
841 TRAPS) {
842
843 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
844 int d_index = dictionary()->hash_to_index(d_hash);
845
846 {
847 // Note that we have an entry, and entries can be deleted only during GC,
848 // so we cannot allow GC to occur while we're holding this entry.
849 // We're using a No_Safepoint_Verifier to catch any place where we
850 // might potentially do a GC at all.
851 // SystemDictionary::do_unloading() asserts that classes are only
852 // unloaded at a safepoint.
853 No_Safepoint_Verifier nosafepoint;
854 return dictionary()->find(d_index, d_hash, class_name, class_loader,
855 protection_domain, THREAD);
856 }
857 }
858
859
860 // Look for a loaded instance or array klass by name. Do not do any loading.
861 // return NULL in case of error.
862 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
863 Handle class_loader,
864 Handle protection_domain,
865 TRAPS) {
866 klassOop k = NULL;
867 assert(class_name() != NULL, "class name must be non NULL");
868
869 // Try to get one of the well-known klasses.
870 k = find_well_known_klass(class_name());
871 if (k != NULL) {
872 return k;
873 }
874
875 if (FieldType::is_array(class_name())) {
876 // The name refers to an array. Parse the name.
877 jint dimension;
878 symbolOop object_key;
879
880 // dimension and object_key are assigned as a side-effect of this call
881 BasicType t = FieldType::get_array_info(class_name(), &dimension,
882 &object_key, CHECK_(NULL));
883 if (t != T_OBJECT) {
884 k = Universe::typeArrayKlassObj(t);
885 } else {
886 symbolHandle h_key(THREAD, object_key);
887 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
888 }
889 if (k != NULL) {
890 k = Klass::cast(k)->array_klass_or_null(dimension);
891 }
892 } else {
893 k = find(class_name, class_loader, protection_domain, THREAD);
894 }
895 return k;
896 }
897
898 // Quick range check for names of well-known classes:
899 static symbolOop wk_klass_name_limits[2] = {NULL, NULL};
900
901 #ifndef PRODUCT
902 static int find_wkk_calls, find_wkk_probes, find_wkk_wins;
903 // counts for "hello world": 3983, 1616, 1075
904 // => 60% hit after limit guard, 25% total win rate
905 #endif
906
907 klassOop SystemDictionary::find_well_known_klass(symbolOop class_name) {
908 // A bounds-check on class_name will quickly get a negative result.
909 NOT_PRODUCT(find_wkk_calls++);
910 if (class_name >= wk_klass_name_limits[0] &&
911 class_name <= wk_klass_name_limits[1]) {
912 NOT_PRODUCT(find_wkk_probes++);
913 vmSymbols::SID sid = vmSymbols::find_sid(class_name);
914 if (sid != vmSymbols::NO_SID) {
915 klassOop k = NULL;
916 switch (sid) {
917 #define WK_KLASS_CASE(name, symbol, ignore_option) \
918 case vmSymbols::VM_SYMBOL_ENUM_NAME(symbol): \
919 k = WK_KLASS(name); break;
920 WK_KLASSES_DO(WK_KLASS_CASE)
921 #undef WK_KLASS_CASE
922 }
923 NOT_PRODUCT(if (k != NULL) find_wkk_wins++);
924 return k;
925 }
926 }
927 return NULL;
928 }
929
930 // Note: this method is much like resolve_from_stream, but
931 // updates no supplemental data structures.
932 // TODO consolidate the two methods with a helper routine?
933 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
934 Handle class_loader,
935 Handle protection_domain,
936 ClassFileStream* st,
937 TRAPS) {
938 symbolHandle parsed_name;
939
940 // Parse the stream. Note that we do this even though this klass might
941 // already be present in the SystemDictionary, otherwise we would not
942 // throw potential ClassFormatErrors.
943 //
944 // Note: "name" is updated.
945 // Further note: a placeholder will be added for this class when
946 // super classes are loaded (resolve_super_or_fail). We expect this
947 // to be called for all classes but java.lang.Object; and we preload
948 // java.lang.Object through resolve_or_fail, not this path.
949
950 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
951 class_loader,
952 protection_domain,
953 parsed_name,
954 THREAD);
955
956
957 // We don't redefine the class, so we just need to clean up whether there
958 // was an error or not (don't want to modify any system dictionary
959 // data structures).
960 // Parsed name could be null if we threw an error before we got far
961 // enough along to parse it -- in that case, there is nothing to clean up.
962 if (!parsed_name.is_null()) {
963 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
964 class_loader);
965 int p_index = placeholders()->hash_to_index(p_hash);
966 {
967 MutexLocker mu(SystemDictionary_lock, THREAD);
968 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
969 SystemDictionary_lock->notify_all();
970 }
971 }
972
973 return k();
974 }
975
976 // Add a klass to the system from a stream (called by jni_DefineClass and
977 // JVM_DefineClass).
978 // Note: class_name can be NULL. In that case we do not know the name of
979 // the class until we have parsed the stream.
980
981 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
982 Handle class_loader,
983 Handle protection_domain,
984 ClassFileStream* st,
985 TRAPS) {
986
987 // Make sure we are synchronized on the class loader before we initiate
988 // loading.
989 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
990 check_loader_lock_contention(lockObject, THREAD);
991 ObjectLocker ol(lockObject, THREAD);
992
993 symbolHandle parsed_name;
994
995 // Parse the stream. Note that we do this even though this klass might
996 // already be present in the SystemDictionary, otherwise we would not
997 // throw potential ClassFormatErrors.
998 //
999 // Note: "name" is updated.
1000 // Further note: a placeholder will be added for this class when
1001 // super classes are loaded (resolve_super_or_fail). We expect this
1002 // to be called for all classes but java.lang.Object; and we preload
1003 // java.lang.Object through resolve_or_fail, not this path.
1004
1005 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1006 class_loader,
1007 protection_domain,
1008 parsed_name,
1009 THREAD);
1010
1011 const char* pkg = "java/";
1012 if (!HAS_PENDING_EXCEPTION &&
1013 !class_loader.is_null() &&
1014 !parsed_name.is_null() &&
1015 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1016 // It is illegal to define classes in the "java." package from
1017 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1018 ResourceMark rm(THREAD);
1019 char* name = parsed_name->as_C_string();
1020 char* index = strrchr(name, '/');
1021 *index = '\0'; // chop to just the package name
1022 while ((index = strchr(name, '/')) != NULL) {
1023 *index = '.'; // replace '/' with '.' in package name
1024 }
1025 const char* fmt = "Prohibited package name: %s";
1026 size_t len = strlen(fmt) + strlen(name);
1027 char* message = NEW_RESOURCE_ARRAY(char, len);
1028 jio_snprintf(message, len, fmt, name);
1029 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1030 vmSymbols::java_lang_SecurityException(), message);
1031 }
1032
1033 if (!HAS_PENDING_EXCEPTION) {
1034 assert(!parsed_name.is_null(), "Sanity");
1035 assert(class_name.is_null() || class_name() == parsed_name(),
1036 "name mismatch");
1037 // Verification prevents us from creating names with dots in them, this
1038 // asserts that that's the case.
1039 assert(is_internal_format(parsed_name),
1040 "external class name format used internally");
1041
1042 // Add class just loaded
1043 define_instance_class(k, THREAD);
1044 }
1045
1046 // If parsing the class file or define_instance_class failed, we
1047 // need to remove the placeholder added on our behalf. But we
1048 // must make sure parsed_name is valid first (it won't be if we had
1049 // a format error before the class was parsed far enough to
1050 // find the name).
1051 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1052 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1053 class_loader);
1054 int p_index = placeholders()->hash_to_index(p_hash);
1055 {
1056 MutexLocker mu(SystemDictionary_lock, THREAD);
1057 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1058 SystemDictionary_lock->notify_all();
1059 }
1060 return NULL;
1061 }
1062
1063 // Make sure that we didn't leave a place holder in the
1064 // SystemDictionary; this is only done on success
1065 debug_only( {
1066 if (!HAS_PENDING_EXCEPTION) {
1067 assert(!parsed_name.is_null(), "parsed_name is still null?");
1068 symbolHandle h_name (THREAD, k->name());
1069 Handle h_loader (THREAD, k->class_loader());
1070
1071 MutexLocker mu(SystemDictionary_lock, THREAD);
1072
1073 oop check = find_class_or_placeholder(parsed_name, class_loader);
1074 assert(check == k(), "should be present in the dictionary");
1075
1076 oop check2 = find_class_or_placeholder(h_name, h_loader);
1077 assert(check == check2, "name inconsistancy in SystemDictionary");
1078 }
1079 } );
1080
1081 return k();
1082 }
1083
1084
1085 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1086 int number_of_entries) {
1087 assert(length == _nof_buckets * sizeof(HashtableBucket),
1088 "bad shared dictionary size.");
1089 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1090 }
1091
1092
1093 // If there is a shared dictionary, then find the entry for the
1094 // given shared system class, if any.
1095
1096 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1097 if (shared_dictionary() != NULL) {
1098 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1099 int d_index = dictionary()->hash_to_index(d_hash);
1100 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1101 } else {
1102 return NULL;
1103 }
1104 }
1105
1106
1107 // Load a class from the shared spaces (found through the shared system
1108 // dictionary). Force the superclass and all interfaces to be loaded.
1109 // Update the class definition to include sibling classes and no
1110 // subclasses (yet). [Classes in the shared space are not part of the
1111 // object hierarchy until loaded.]
1112
1113 instanceKlassHandle SystemDictionary::load_shared_class(
1114 symbolHandle class_name, Handle class_loader, TRAPS) {
1115 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1116 return load_shared_class(ik, class_loader, THREAD);
1117 }
1118
1119 // Note well! Changes to this method may affect oop access order
1120 // in the shared archive. Please take care to not make changes that
1121 // adversely affect cold start time by changing the oop access order
1122 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1123 // MarkAndMoveOrderedReadWrite closures.
1124 instanceKlassHandle SystemDictionary::load_shared_class(
1125 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1126 assert(class_loader.is_null(), "non-null classloader for shared class?");
1127 if (ik.not_null()) {
1128 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1129 symbolHandle class_name(THREAD, ik->name());
1130
1131 // Found the class, now load the superclass and interfaces. If they
1132 // are shared, add them to the main system dictionary and reset
1133 // their hierarchy references (supers, subs, and interfaces).
1134
1135 if (ik->super() != NULL) {
1136 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1137 resolve_super_or_fail(class_name, cn,
1138 class_loader, Handle(), true, CHECK_(nh));
1139 }
1140
1141 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1142 int num_interfaces = interfaces->length();
1143 for (int index = 0; index < num_interfaces; index++) {
1144 klassOop k = klassOop(interfaces->obj_at(index));
1145
1146 // Note: can not use instanceKlass::cast here because
1147 // interfaces' instanceKlass's C++ vtbls haven't been
1148 // reinitialized yet (they will be once the interface classes
1149 // are loaded)
1150 symbolHandle name (THREAD, k->klass_part()->name());
1151 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1152 }
1153
1154 // Adjust methods to recover missing data. They need addresses for
1155 // interpreter entry points and their default native method address
1156 // must be reset.
1157
1158 // Updating methods must be done under a lock so multiple
1159 // threads don't update these in parallel
1160 // Shared classes are all currently loaded by the bootstrap
1161 // classloader, so this will never cause a deadlock on
1162 // a custom class loader lock.
1163
1164 {
1165 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1166 check_loader_lock_contention(lockObject, THREAD);
1167 ObjectLocker ol(lockObject, THREAD, true);
1168
1169 objArrayHandle methods (THREAD, ik->methods());
1170 int num_methods = methods->length();
1171 for (int index2 = 0; index2 < num_methods; ++index2) {
1172 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1173 m()->link_method(m, CHECK_(nh));
1174 }
1175 }
1176
1177 if (TraceClassLoading) {
1178 ResourceMark rm;
1179 tty->print("[Loaded %s", ik->external_name());
1180 tty->print(" from shared objects file");
1181 tty->print_cr("]");
1182 }
1183 // notify a class loaded from shared object
1184 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1185 true /* shared class */);
1186 }
1187 return ik;
1188 }
1189
1190 #ifdef KERNEL
1191 // Some classes on the bootstrap class path haven't been installed on the
1192 // system yet. Call the DownloadManager method to make them appear in the
1193 // bootstrap class path and try again to load the named class.
1194 // Note that with delegation class loaders all classes in another loader will
1195 // first try to call this so it'd better be fast!!
1196 static instanceKlassHandle download_and_retry_class_load(
1197 symbolHandle class_name,
1198 TRAPS) {
1199
1200 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1201 instanceKlassHandle nk;
1202
1203 // If download manager class isn't loaded just return.
1204 if (dlm == NULL) return nk;
1205
1206 { HandleMark hm(THREAD);
1207 ResourceMark rm(THREAD);
1208 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1209 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1210
1211 // return value
1212 JavaValue result(T_OBJECT);
1213
1214 // Call the DownloadManager. We assume that it has a lock because
1215 // multiple classes could be not found and downloaded at the same time.
1216 // class sun.misc.DownloadManager;
1217 // public static String getBootClassPathEntryForClass(String className);
1218 JavaCalls::call_static(&result,
1219 KlassHandle(THREAD, dlm),
1220 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1221 vmSymbolHandles::string_string_signature(),
1222 class_string,
1223 CHECK_(nk));
1224
1225 // Get result.string and add to bootclasspath
1226 assert(result.get_type() == T_OBJECT, "just checking");
1227 oop obj = (oop) result.get_jobject();
1228 if (obj == NULL) { return nk; }
1229
1230 char* new_class_name = java_lang_String::as_utf8_string(obj);
1231
1232 // lock the loader
1233 // we use this lock because JVMTI does.
1234 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1235
1236 ObjectLocker ol(loader_lock, THREAD);
1237 // add the file to the bootclasspath
1238 ClassLoader::update_class_path_entry_list(new_class_name, true);
1239 } // end HandleMark
1240
1241 if (TraceClassLoading) {
1242 ClassLoader::print_bootclasspath();
1243 }
1244 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1245 }
1246 #endif // KERNEL
1247
1248
1249 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1250 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1251 if (class_loader.is_null()) {
1252 // Search the shared system dictionary for classes preloaded into the
1253 // shared spaces.
1254 instanceKlassHandle k;
1255 k = load_shared_class(class_name, class_loader, THREAD);
1256
1257 if (k.is_null()) {
1258 // Use VM class loader
1259 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1260 }
1261
1262 #ifdef KERNEL
1263 // If the VM class loader has failed to load the class, call the
1264 // DownloadManager class to make it magically appear on the classpath
1265 // and try again. This is only configured with the Kernel VM.
1266 if (k.is_null()) {
1267 k = download_and_retry_class_load(class_name, CHECK_(nh));
1268 }
1269 #endif // KERNEL
1270
1271 // find_or_define_instance_class may return a different k
1272 if (!k.is_null()) {
1273 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1274 }
1275 return k;
1276 } else {
1277 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1278 ResourceMark rm(THREAD);
1279
1280 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1281 // Translate to external class name format, i.e., convert '/' chars to '.'
1282 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1283
1284 JavaValue result(T_OBJECT);
1285
1286 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1287
1288 // UnsyncloadClass option means don't synchronize loadClass() calls.
1289 // loadClassInternal() is synchronized and public loadClass(String) is not.
1290 // This flag is for diagnostic purposes only. It is risky to call
1291 // custom class loaders without synchronization.
1292 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1293 // findClass, this flag risks unexpected timing bugs in the field.
1294 // Do NOT assume this will be supported in future releases.
1295 if (!UnsyncloadClass && has_loadClassInternal()) {
1296 JavaCalls::call_special(&result,
1297 class_loader,
1298 spec_klass,
1299 vmSymbolHandles::loadClassInternal_name(),
1300 vmSymbolHandles::string_class_signature(),
1301 string,
1302 CHECK_(nh));
1303 } else {
1304 JavaCalls::call_virtual(&result,
1305 class_loader,
1306 spec_klass,
1307 vmSymbolHandles::loadClass_name(),
1308 vmSymbolHandles::string_class_signature(),
1309 string,
1310 CHECK_(nh));
1311 }
1312
1313 assert(result.get_type() == T_OBJECT, "just checking");
1314 oop obj = (oop) result.get_jobject();
1315
1316 // Primitive classes return null since forName() can not be
1317 // used to obtain any of the Class objects representing primitives or void
1318 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1319 instanceKlassHandle k =
1320 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1321 // For user defined Java class loaders, check that the name returned is
1322 // the same as that requested. This check is done for the bootstrap
1323 // loader when parsing the class file.
1324 if (class_name() == k->name()) {
1325 return k;
1326 }
1327 }
1328 // Class is not found or has the wrong name, return NULL
1329 return nh;
1330 }
1331 }
1332
1333 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1334
1335 Handle class_loader_h(THREAD, k->class_loader());
1336
1337 // for bootstrap classloader don't acquire lock
1338 if (!class_loader_h.is_null()) {
1339 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1340 compute_loader_lock_object(class_loader_h, THREAD)),
1341 "define called without lock");
1342 }
1343
1344
1345 // Check class-loading constraints. Throw exception if violation is detected.
1346 // Grabs and releases SystemDictionary_lock
1347 // The check_constraints/find_class call and update_dictionary sequence
1348 // must be "atomic" for a specific class/classloader pair so we never
1349 // define two different instanceKlasses for that class/classloader pair.
1350 // Existing classloaders will call define_instance_class with the
1351 // classloader lock held
1352 // Parallel classloaders will call find_or_define_instance_class
1353 // which will require a token to perform the define class
1354 symbolHandle name_h(THREAD, k->name());
1355 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1356 int d_index = dictionary()->hash_to_index(d_hash);
1357 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1358
1359 // Register class just loaded with class loader (placed in Vector)
1360 // Note we do this before updating the dictionary, as this can
1361 // fail with an OutOfMemoryError (if it does, we will *not* put this
1362 // class in the dictionary and will not update the class hierarchy).
1363 if (k->class_loader() != NULL) {
1364 methodHandle m(THREAD, Universe::loader_addClass_method());
1365 JavaValue result(T_VOID);
1366 JavaCallArguments args(class_loader_h);
1367 args.push_oop(Handle(THREAD, k->java_mirror()));
1368 JavaCalls::call(&result, m, &args, CHECK);
1369 }
1370
1371 // Add the new class. We need recompile lock during update of CHA.
1372 {
1373 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1374 int p_index = placeholders()->hash_to_index(p_hash);
1375
1376 MutexLocker mu_r(Compile_lock, THREAD);
1377
1378 // Add to class hierarchy, initialize vtables, and do possible
1379 // deoptimizations.
1380 add_to_hierarchy(k, CHECK); // No exception, but can block
1381
1382 // Add to systemDictionary - so other classes can see it.
1383 // Grabs and releases SystemDictionary_lock
1384 update_dictionary(d_index, d_hash, p_index, p_hash,
1385 k, class_loader_h, THREAD);
1386 }
1387 k->eager_initialize(THREAD);
1388
1389 // notify jvmti
1390 if (JvmtiExport::should_post_class_load()) {
1391 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1392 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1393
1394 }
1395 }
1396
1397 // Support parallel classloading
1398 // Initial implementation for bootstrap classloader
1399 // For future:
1400 // For custom class loaders that support parallel classloading,
1401 // in case they do not synchronize around
1402 // FindLoadedClass/DefineClass calls, we check for parallel
1403 // loading for them, wait if a defineClass is in progress
1404 // and return the initial requestor's results
1405 // For better performance, the class loaders should synchronize
1406 // findClass(), i.e. FindLoadedClass/DefineClass or they
1407 // potentially waste time reading and parsing the bytestream.
1408 // Note: VM callers should ensure consistency of k/class_name,class_loader
1409 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1410
1411 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1412
1413 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1414 int d_index = dictionary()->hash_to_index(d_hash);
1415
1416 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1417 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1418 int p_index = placeholders()->hash_to_index(p_hash);
1419 PlaceholderEntry* probe;
1420
1421 {
1422 MutexLocker mu(SystemDictionary_lock, THREAD);
1423 // First check if class already defined
1424 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1425 if (check != NULL) {
1426 return(instanceKlassHandle(THREAD, check));
1427 }
1428
1429 // Acquire define token for this class/classloader
1430 symbolHandle nullsymbolHandle;
1431 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1432 // Check if another thread defining in parallel
1433 if (probe->definer() == NULL) {
1434 // Thread will define the class
1435 probe->set_definer(THREAD);
1436 } else {
1437 // Wait for defining thread to finish and return results
1438 while (probe->definer() != NULL) {
1439 SystemDictionary_lock->wait();
1440 }
1441 if (probe->instanceKlass() != NULL) {
1442 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1443 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1444 } else {
1445 // If definer had an error, try again as any new thread would
1446 probe->set_definer(THREAD);
1447 #ifdef ASSERT
1448 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1449 assert(check == NULL, "definer missed recording success");
1450 #endif
1451 }
1452 }
1453 }
1454
1455 define_instance_class(k, THREAD);
1456
1457 Handle linkage_exception = Handle(); // null handle
1458
1459 // definer must notify any waiting threads
1460 {
1461 MutexLocker mu(SystemDictionary_lock, THREAD);
1462 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader);
1463 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1464 if (probe != NULL) {
1465 if (HAS_PENDING_EXCEPTION) {
1466 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1467 CLEAR_PENDING_EXCEPTION;
1468 } else {
1469 probe->set_instanceKlass(k());
1470 }
1471 probe->set_definer(NULL);
1472 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1473 SystemDictionary_lock->notify_all();
1474 }
1475 }
1476
1477 // Can't throw exception while holding lock due to rank ordering
1478 if (linkage_exception() != NULL) {
1479 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1480 }
1481
1482 return k;
1483 }
1484
1485 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1486 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1487 if (class_loader.is_null()) {
1488 return Handle(THREAD, _system_loader_lock_obj);
1489 } else {
1490 return class_loader;
1491 }
1492 }
1493
1494 // This method is added to check how often we have to wait to grab loader
1495 // lock. The results are being recorded in the performance counters defined in
1496 // ClassLoader::_sync_systemLoaderLockContentionRate and
1497 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1498 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1499 if (!UsePerfData) {
1500 return;
1501 }
1502
1503 assert(!loader_lock.is_null(), "NULL lock object");
1504
1505 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1506 == ObjectSynchronizer::owner_other) {
1507 // contention will likely happen, so increment the corresponding
1508 // contention counter.
1509 if (loader_lock() == _system_loader_lock_obj) {
1510 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1511 } else {
1512 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1513 }
1514 }
1515 }
1516
1517 // ----------------------------------------------------------------------------
1518 // Lookup
1519
1520 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1521 symbolHandle class_name,
1522 Handle class_loader) {
1523 assert_locked_or_safepoint(SystemDictionary_lock);
1524 assert (index == dictionary()->index_for(class_name, class_loader),
1525 "incorrect index?");
1526
1527 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1528 return k;
1529 }
1530
1531
1532 // Basic find on classes in the midst of being loaded
1533 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1534 symbolHandle class_name,
1535 Handle class_loader) {
1536 assert_locked_or_safepoint(SystemDictionary_lock);
1537
1538 return placeholders()->find_entry(index, hash, class_name, class_loader);
1539 }
1540
1541
1542 // Used for assertions and verification only
1543 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1544 Handle class_loader) {
1545 #ifndef ASSERT
1546 guarantee(VerifyBeforeGC ||
1547 VerifyDuringGC ||
1548 VerifyBeforeExit ||
1549 VerifyAfterGC, "too expensive");
1550 #endif
1551 assert_locked_or_safepoint(SystemDictionary_lock);
1552 symbolOop class_name_ = class_name();
1553 oop class_loader_ = class_loader();
1554
1555 // First look in the loaded class array
1556 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1557 int d_index = dictionary()->hash_to_index(d_hash);
1558 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1559
1560 if (lookup == NULL) {
1561 // Next try the placeholders
1562 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1563 int p_index = placeholders()->hash_to_index(p_hash);
1564 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1565 }
1566
1567 return lookup;
1568 }
1569
1570
1571 // Get the next class in the diictionary.
1572 klassOop SystemDictionary::try_get_next_class() {
1573 return dictionary()->try_get_next_class();
1574 }
1575
1576
1577 // ----------------------------------------------------------------------------
1578 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1579 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1580 // before a new class is used.
1581
1582 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1583 assert(k.not_null(), "just checking");
1584 // Link into hierachy. Make sure the vtables are initialized before linking into
1585 k->append_to_sibling_list(); // add to superklass/sibling list
1586 k->process_interfaces(THREAD); // handle all "implements" declarations
1587 k->set_init_state(instanceKlass::loaded);
1588 // Now flush all code that depended on old class hierarchy.
1589 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1590 // Also, first reinitialize vtable because it may have gotten out of synch
1591 // while the new class wasn't connected to the class hierarchy.
1592 Universe::flush_dependents_on(k);
1593 }
1594
1595
1596 // ----------------------------------------------------------------------------
1597 // GC support
1598
1599 // Following roots during mark-sweep is separated in two phases.
1600 //
1601 // The first phase follows preloaded classes and all other system
1602 // classes, since these will never get unloaded anyway.
1603 //
1604 // The second phase removes (unloads) unreachable classes from the
1605 // system dictionary and follows the remaining classes' contents.
1606
1607 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1608 // Follow preloaded classes/mirrors and system loader object
1609 blk->do_oop(&_java_system_loader);
1610 preloaded_oops_do(blk);
1611 always_strong_classes_do(blk);
1612 }
1613
1614
1615 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1616 // Follow all system classes and temporary placeholders in dictionary
1617 dictionary()->always_strong_classes_do(blk);
1618
1619 // Placeholders. These are *always* strong roots, as they
1620 // represent classes we're actively loading.
1621 placeholders_do(blk);
1622
1623 // Loader constraints. We must keep the symbolOop used in the name alive.
1624 constraints()->always_strong_classes_do(blk);
1625
1626 // Resolution errors keep the symbolOop for the error alive
1627 resolution_errors()->always_strong_classes_do(blk);
1628 }
1629
1630
1631 void SystemDictionary::placeholders_do(OopClosure* blk) {
1632 placeholders()->oops_do(blk);
1633 }
1634
1635
1636 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1637 bool result = dictionary()->do_unloading(is_alive);
1638 constraints()->purge_loader_constraints(is_alive);
1639 resolution_errors()->purge_resolution_errors(is_alive);
1640 return result;
1641 }
1642
1643
1644 // The mirrors are scanned by shared_oops_do() which is
1645 // not called by oops_do(). In order to process oops in
1646 // a necessary order, shared_oops_do() is call by
1647 // Universe::oops_do().
1648 void SystemDictionary::oops_do(OopClosure* f) {
1649 // Adjust preloaded classes and system loader object
1650 f->do_oop(&_java_system_loader);
1651 preloaded_oops_do(f);
1652
1653 lazily_loaded_oops_do(f);
1654
1655 // Adjust dictionary
1656 dictionary()->oops_do(f);
1657
1658 // Partially loaded classes
1659 placeholders()->oops_do(f);
1660
1661 // Adjust constraint table
1662 constraints()->oops_do(f);
1663
1664 // Adjust resolution error table
1665 resolution_errors()->oops_do(f);
1666 }
1667
1668
1669 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1670 f->do_oop((oop*) &wk_klass_name_limits[0]);
1671 f->do_oop((oop*) &wk_klass_name_limits[1]);
1672
1673 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1674 f->do_oop((oop*) &_well_known_klasses[k]);
1675 }
1676
1677 {
1678 for (int i = 0; i < T_VOID+1; i++) {
1679 if (_box_klasses[i] != NULL) {
1680 assert(i >= T_BOOLEAN, "checking");
1681 f->do_oop((oop*) &_box_klasses[i]);
1682 }
1683 }
1684 }
1685
1686 // The basic type mirrors would have already been processed in
1687 // Universe::oops_do(), via a call to shared_oops_do(), so should
1688 // not be processed again.
1689
1690 f->do_oop((oop*) &_system_loader_lock_obj);
1691 FilteredFieldsMap::klasses_oops_do(f);
1692 }
1693
1694 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1695 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1696 }
1697
1698 // Just the classes from defining class loaders
1699 // Don't iterate over placeholders
1700 void SystemDictionary::classes_do(void f(klassOop)) {
1701 dictionary()->classes_do(f);
1702 }
1703
1704 // Added for initialize_itable_for_klass
1705 // Just the classes from defining class loaders
1706 // Don't iterate over placeholders
1707 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1708 dictionary()->classes_do(f, CHECK);
1709 }
1710
1711 // All classes, and their class loaders
1712 // Don't iterate over placeholders
1713 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1714 dictionary()->classes_do(f);
1715 }
1716
1717 // All classes, and their class loaders
1718 // (added for helpers that use HandleMarks and ResourceMarks)
1719 // Don't iterate over placeholders
1720 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1721 dictionary()->classes_do(f, CHECK);
1722 }
1723
1724 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1725 placeholders()->entries_do(f);
1726 }
1727
1728 void SystemDictionary::methods_do(void f(methodOop)) {
1729 dictionary()->methods_do(f);
1730 }
1731
1732 // ----------------------------------------------------------------------------
1733 // Lazily load klasses
1734
1735 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1736 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1737
1738 // if multiple threads calling this function, only one thread will load
1739 // the class. The other threads will find the loaded version once the
1740 // class is loaded.
1741 klassOop aos = _abstract_ownable_synchronizer_klass;
1742 if (aos == NULL) {
1743 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1744 // Force a fence to prevent any read before the write completes
1745 OrderAccess::fence();
1746 _abstract_ownable_synchronizer_klass = k;
1747 }
1748 }
1749
1750 // ----------------------------------------------------------------------------
1751 // Initialization
1752
1753 void SystemDictionary::initialize(TRAPS) {
1754 // Allocate arrays
1755 assert(dictionary() == NULL,
1756 "SystemDictionary should only be initialized once");
1757 _dictionary = new Dictionary(_nof_buckets);
1758 _placeholders = new PlaceholderTable(_nof_buckets);
1759 _number_of_modifications = 0;
1760 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1761 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1762
1763 // Allocate private object used as system class loader lock
1764 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1765 // Initialize basic classes
1766 initialize_preloaded_classes(CHECK);
1767 }
1768
1769 // Compact table of directions on the initialization of klasses:
1770 static const short wk_init_info[] = {
1771 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1772 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) << 1) \
1773 | (SystemDictionary::option < SystemDictionary::Opt ? 0 : 1) ),
1774 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1775 #undef WK_KLASS_INIT_INFO
1776 0
1777 };
1778
1779 bool SystemDictionary::initialize_wk_klass(WKID id, bool must_load, TRAPS) {
1780 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1781 int info = wk_init_info[id - FIRST_WKID];
1782 int sid = (info >> 1);
1783 symbolHandle symbol = vmSymbolHandles::symbol_handle_at((vmSymbols::SID)sid);
1784 klassOop* klassp = &_well_known_klasses[id];
1785 if ((*klassp) == NULL) {
1786 if (must_load) {
1787 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1788 } else {
1789 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1790 }
1791 }
1792 return ((*klassp) != NULL);
1793 }
1794
1795 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1796 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1797 for (int id = (int)start_id; id < (int)limit_id; id++) {
1798 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1799 int info = wk_init_info[id - FIRST_WKID];
1800 int sid = (info >> 1);
1801 bool opt = (info & 1);
1802
1803 initialize_wk_klass((WKID)id, !opt, CHECK);
1804
1805 // Update limits, so find_well_known_klass can be very fast:
1806 symbolOop s = vmSymbols::symbol_at((vmSymbols::SID)sid);
1807 if (wk_klass_name_limits[1] == NULL) {
1808 wk_klass_name_limits[0] = wk_klass_name_limits[1] = s;
1809 } else if (wk_klass_name_limits[1] < s) {
1810 wk_klass_name_limits[1] = s;
1811 } else if (wk_klass_name_limits[0] > s) {
1812 wk_klass_name_limits[0] = s;
1813 }
1814 }
1815 }
1816
1817
1818 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1819 assert(WK_KLASS(object_klass) == NULL, "preloaded classes should only be initialized once");
1820 // Preload commonly used klasses
1821 WKID scan = FIRST_WKID;
1822 // first do Object, String, Class
1823 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(class_klass), scan, CHECK);
1824
1825 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(WK_KLASS(class_klass)));
1826
1827 // Fixup mirrors for classes loaded before java.lang.Class.
1828 // These calls iterate over the objects currently in the perm gen
1829 // so calling them at this point is matters (not before when there
1830 // are fewer objects and not later after there are more objects
1831 // in the perm gen.
1832 Universe::initialize_basic_type_mirrors(CHECK);
1833 Universe::fixup_mirrors(CHECK);
1834
1835 // do a bunch more:
1836 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(reference_klass), scan, CHECK);
1837
1838 // Preload ref klasses and set reference types
1839 instanceKlass::cast(WK_KLASS(reference_klass))->set_reference_type(REF_OTHER);
1840 instanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(reference_klass));
1841
1842 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(phantom_reference_klass), scan, CHECK);
1843 instanceKlass::cast(WK_KLASS(soft_reference_klass))->set_reference_type(REF_SOFT);
1844 instanceKlass::cast(WK_KLASS(weak_reference_klass))->set_reference_type(REF_WEAK);
1845 instanceKlass::cast(WK_KLASS(final_reference_klass))->set_reference_type(REF_FINAL);
1846 instanceKlass::cast(WK_KLASS(phantom_reference_klass))->set_reference_type(REF_PHANTOM);
1847
1848 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
1849
1850 _box_klasses[T_BOOLEAN] = WK_KLASS(boolean_klass);
1851 _box_klasses[T_CHAR] = WK_KLASS(char_klass);
1852 _box_klasses[T_FLOAT] = WK_KLASS(float_klass);
1853 _box_klasses[T_DOUBLE] = WK_KLASS(double_klass);
1854 _box_klasses[T_BYTE] = WK_KLASS(byte_klass);
1855 _box_klasses[T_SHORT] = WK_KLASS(short_klass);
1856 _box_klasses[T_INT] = WK_KLASS(int_klass);
1857 _box_klasses[T_LONG] = WK_KLASS(long_klass);
1858 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
1859 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
1860
1861 #ifdef KERNEL
1862 _sun_jkernel_DownloadManager_klass = resolve_or_null(vmSymbolHandles::sun_jkernel_DownloadManager(), CHECK);
1863 if (_sun_jkernel_DownloadManager_klass == NULL) {
1864 warning("Cannot find sun/jkernel/DownloadManager");
1865 }
1866 #endif // KERNEL
1867 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1868 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1869 _has_loadClassInternal = (method != NULL);
1870 }
1871
1872 { // Compute whether we should use checkPackageAccess or NOT
1873 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1874 _has_checkPackageAccess = (method != NULL);
1875 }
1876 }
1877
1878 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1879 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1880 BasicType SystemDictionary::box_klass_type(klassOop k) {
1881 assert(k != NULL, "");
1882 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1883 if (_box_klasses[i] == k)
1884 return (BasicType)i;
1885 }
1886 return T_OBJECT;
1887 }
1888
1889 // Constraints on class loaders. The details of the algorithm can be
1890 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1891 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1892 // that the system dictionary needs to maintain a set of contraints that
1893 // must be satisfied by all classes in the dictionary.
1894 // if defining is true, then LinkageError if already in systemDictionary
1895 // if initiating loader, then ok if instanceKlass matches existing entry
1896
1897 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1898 instanceKlassHandle k,
1899 Handle class_loader, bool defining,
1900 TRAPS) {
1901 const char *linkage_error = NULL;
1902 {
1903 symbolHandle name (THREAD, k->name());
1904 MutexLocker mu(SystemDictionary_lock, THREAD);
1905
1906 klassOop check = find_class(d_index, d_hash, name, class_loader);
1907 if (check != (klassOop)NULL) {
1908 // if different instanceKlass - duplicate class definition,
1909 // else - ok, class loaded by a different thread in parallel,
1910 // we should only have found it if it was done loading and ok to use
1911 // system dictionary only holds instance classes, placeholders
1912 // also holds array classes
1913
1914 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
1915 if ((defining == true) || (k() != check)) {
1916 linkage_error = "loader (instance of %s): attempted duplicate class "
1917 "definition for name: \"%s\"";
1918 } else {
1919 return;
1920 }
1921 }
1922
1923 #ifdef ASSERT
1924 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
1925 int p_index = placeholders()->hash_to_index(p_hash);
1926 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
1927 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
1928 #endif
1929
1930 if (linkage_error == NULL) {
1931 if (constraints()->check_or_update(k, class_loader, name) == false) {
1932 linkage_error = "loader constraint violation: loader (instance of %s)"
1933 " previously initiated loading for a different type with name \"%s\"";
1934 }
1935 }
1936 }
1937
1938 // Throw error now if needed (cannot throw while holding
1939 // SystemDictionary_lock because of rank ordering)
1940
1941 if (linkage_error) {
1942 ResourceMark rm(THREAD);
1943 const char* class_loader_name = loader_name(class_loader());
1944 char* type_name = k->name()->as_C_string();
1945 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
1946 strlen(type_name);
1947 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
1948 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
1949 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
1950 }
1951 }
1952
1953
1954 // Update system dictionary - done after check_constraint and add_to_hierachy
1955 // have been called.
1956 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
1957 int p_index, unsigned int p_hash,
1958 instanceKlassHandle k,
1959 Handle class_loader,
1960 TRAPS) {
1961 // Compile_lock prevents systemDictionary updates during compilations
1962 assert_locked_or_safepoint(Compile_lock);
1963 symbolHandle name (THREAD, k->name());
1964
1965 {
1966 MutexLocker mu1(SystemDictionary_lock, THREAD);
1967
1968 // See whether biased locking is enabled and if so set it for this
1969 // klass.
1970 // Note that this must be done past the last potential blocking
1971 // point / safepoint. We enable biased locking lazily using a
1972 // VM_Operation to iterate the SystemDictionary and installing the
1973 // biasable mark word into each instanceKlass's prototype header.
1974 // To avoid race conditions where we accidentally miss enabling the
1975 // optimization for one class in the process of being added to the
1976 // dictionary, we must not safepoint after the test of
1977 // BiasedLocking::enabled().
1978 if (UseBiasedLocking && BiasedLocking::enabled()) {
1979 // Set biased locking bit for all loaded classes; it will be
1980 // cleared if revocation occurs too often for this type
1981 // NOTE that we must only do this when the class is initally
1982 // defined, not each time it is referenced from a new class loader
1983 if (k->class_loader() == class_loader()) {
1984 k->set_prototype_header(markOopDesc::biased_locking_prototype());
1985 }
1986 }
1987
1988 // Check for a placeholder. If there, remove it and make a
1989 // new system dictionary entry.
1990 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
1991 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
1992 if (sd_check == NULL) {
1993 dictionary()->add_klass(name, class_loader, k);
1994 notice_modification();
1995 }
1996 #ifdef ASSERT
1997 sd_check = find_class(d_index, d_hash, name, class_loader);
1998 assert (sd_check != NULL, "should have entry in system dictionary");
1999 // Changed to allow PH to remain to complete class circularity checking
2000 // while only one thread can define a class at one time, multiple
2001 // classes can resolve the superclass for a class at one time,
2002 // and the placeholder is used to track that
2003 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2004 // assert (ph_check == NULL, "should not have a placeholder entry");
2005 #endif
2006 SystemDictionary_lock->notify_all();
2007 }
2008 }
2009
2010
2011 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2012 symbolHandle class_name, Handle class_loader, TRAPS) {
2013
2014 // First see if it has been loaded directly.
2015 // Force the protection domain to be null. (This removes protection checks.)
2016 Handle no_protection_domain;
2017 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2018 no_protection_domain, CHECK_NULL);
2019 if (klass != NULL)
2020 return klass;
2021
2022 // Now look to see if it has been loaded elsewhere, and is subject to
2023 // a loader constraint that would require this loader to return the
2024 // klass that is already loaded.
2025 if (FieldType::is_array(class_name())) {
2026 // Array classes are hard because their klassOops are not kept in the
2027 // constraint table. The array klass may be constrained, but the elem class
2028 // may not be.
2029 jint dimension;
2030 symbolOop object_key;
2031 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2032 &object_key, CHECK_(NULL));
2033 if (t != T_OBJECT) {
2034 klass = Universe::typeArrayKlassObj(t);
2035 } else {
2036 symbolHandle elem_name(THREAD, object_key);
2037 MutexLocker mu(SystemDictionary_lock, THREAD);
2038 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2039 }
2040 if (klass != NULL) {
2041 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2042 }
2043 } else {
2044 MutexLocker mu(SystemDictionary_lock, THREAD);
2045 // Non-array classes are easy: simply check the constraint table.
2046 klass = constraints()->find_constrained_klass(class_name, class_loader);
2047 }
2048
2049 return klass;
2050 }
2051
2052
2053 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2054 Handle class_loader1,
2055 Handle class_loader2,
2056 Thread* THREAD) {
2057 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2058 int d_index1 = dictionary()->hash_to_index(d_hash1);
2059
2060 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2061 int d_index2 = dictionary()->hash_to_index(d_hash2);
2062
2063 {
2064 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2065
2066 // Better never do a GC while we're holding these oops
2067 No_Safepoint_Verifier nosafepoint;
2068
2069 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2070 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2071 return constraints()->add_entry(class_name, klass1, class_loader1,
2072 klass2, class_loader2);
2073 }
2074 }
2075
2076 // Add entry to resolution error table to record the error when the first
2077 // attempt to resolve a reference to a class has failed.
2078 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2079 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2080 int index = resolution_errors()->hash_to_index(hash);
2081 {
2082 MutexLocker ml(SystemDictionary_lock, Thread::current());
2083 resolution_errors()->add_entry(index, hash, pool, which, error);
2084 }
2085 }
2086
2087 // Lookup resolution error table. Returns error if found, otherwise NULL.
2088 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2089 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2090 int index = resolution_errors()->hash_to_index(hash);
2091 {
2092 MutexLocker ml(SystemDictionary_lock, Thread::current());
2093 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2094 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2095 }
2096 }
2097
2098
2099 // Make sure all class components (including arrays) in the given
2100 // signature will be resolved to the same class in both loaders.
2101 // Returns the name of the type that failed a loader constraint check, or
2102 // NULL if no constraint failed. The returned C string needs cleaning up
2103 // with a ResourceMark in the caller
2104 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2105 Handle loader1, Handle loader2,
2106 bool is_method, TRAPS) {
2107 // Nothing to do if loaders are the same.
2108 if (loader1() == loader2()) {
2109 return NULL;
2110 }
2111
2112 SignatureStream sig_strm(signature, is_method);
2113 while (!sig_strm.is_done()) {
2114 if (sig_strm.is_object()) {
2115 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2116 symbolHandle sig (THREAD, s);
2117 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2118 return sig()->as_C_string();
2119 }
2120 }
2121 sig_strm.next();
2122 }
2123 return NULL;
2124 }
2125
2126
2127 // Since the identity hash code for symbols changes when the symbols are
2128 // moved from the regular perm gen (hash in the mark word) to the shared
2129 // spaces (hash is the address), the classes loaded into the dictionary
2130 // may be in the wrong buckets.
2131
2132 void SystemDictionary::reorder_dictionary() {
2133 dictionary()->reorder_dictionary();
2134 }
2135
2136
2137 void SystemDictionary::copy_buckets(char** top, char* end) {
2138 dictionary()->copy_buckets(top, end);
2139 }
2140
2141
2142 void SystemDictionary::copy_table(char** top, char* end) {
2143 dictionary()->copy_table(top, end);
2144 }
2145
2146
2147 void SystemDictionary::reverse() {
2148 dictionary()->reverse();
2149 }
2150
2151 int SystemDictionary::number_of_classes() {
2152 return dictionary()->number_of_entries();
2153 }
2154
2155
2156 // ----------------------------------------------------------------------------
2157 #ifndef PRODUCT
2158
2159 void SystemDictionary::print() {
2160 dictionary()->print();
2161
2162 // Placeholders
2163 GCMutexLocker mu(SystemDictionary_lock);
2164 placeholders()->print();
2165
2166 // loader constraints - print under SD_lock
2167 constraints()->print();
2168 }
2169
2170 #endif
2171
2172 void SystemDictionary::verify() {
2173 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2174 guarantee(constraints() != NULL,
2175 "Verify of loader constraints failed");
2176 guarantee(dictionary()->number_of_entries() >= 0 &&
2177 placeholders()->number_of_entries() >= 0,
2178 "Verify of system dictionary failed");
2179
2180 // Verify dictionary
2181 dictionary()->verify();
2182
2183 GCMutexLocker mu(SystemDictionary_lock);
2184 placeholders()->verify();
2185
2186 // Verify constraint table
2187 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2188 constraints()->verify(dictionary());
2189 }
2190
2191
2192 void SystemDictionary::verify_obj_klass_present(Handle obj,
2193 symbolHandle class_name,
2194 Handle class_loader) {
2195 GCMutexLocker mu(SystemDictionary_lock);
2196 oop probe = find_class_or_placeholder(class_name, class_loader);
2197 if (probe == NULL) {
2198 probe = SystemDictionary::find_shared_class(class_name);
2199 }
2200 guarantee(probe != NULL &&
2201 (!probe->is_klass() || probe == obj()),
2202 "Loaded klasses should be in SystemDictionary");
2203 }
2204
2205 #ifndef PRODUCT
2206
2207 // statistics code
2208 class ClassStatistics: AllStatic {
2209 private:
2210 static int nclasses; // number of classes
2211 static int nmethods; // number of methods
2212 static int nmethoddata; // number of methodData
2213 static int class_size; // size of class objects in words
2214 static int method_size; // size of method objects in words
2215 static int debug_size; // size of debug info in methods
2216 static int methoddata_size; // size of methodData objects in words
2217
2218 static void do_class(klassOop k) {
2219 nclasses++;
2220 class_size += k->size();
2221 if (k->klass_part()->oop_is_instance()) {
2222 instanceKlass* ik = (instanceKlass*)k->klass_part();
2223 class_size += ik->methods()->size();
2224 class_size += ik->constants()->size();
2225 class_size += ik->local_interfaces()->size();
2226 class_size += ik->transitive_interfaces()->size();
2227 // We do not have to count implementors, since we only store one!
2228 class_size += ik->fields()->size();
2229 }
2230 }
2231
2232 static void do_method(methodOop m) {
2233 nmethods++;
2234 method_size += m->size();
2235 // class loader uses same objArray for empty vectors, so don't count these
2236 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2237 if (m->has_stackmap_table()) {
2238 method_size += m->stackmap_data()->size();
2239 }
2240
2241 methodDataOop mdo = m->method_data();
2242 if (mdo != NULL) {
2243 nmethoddata++;
2244 methoddata_size += mdo->size();
2245 }
2246 }
2247
2248 public:
2249 static void print() {
2250 SystemDictionary::classes_do(do_class);
2251 SystemDictionary::methods_do(do_method);
2252 tty->print_cr("Class statistics:");
2253 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2254 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2255 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2256 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2257 }
2258 };
2259
2260
2261 int ClassStatistics::nclasses = 0;
2262 int ClassStatistics::nmethods = 0;
2263 int ClassStatistics::nmethoddata = 0;
2264 int ClassStatistics::class_size = 0;
2265 int ClassStatistics::method_size = 0;
2266 int ClassStatistics::debug_size = 0;
2267 int ClassStatistics::methoddata_size = 0;
2268
2269 void SystemDictionary::print_class_statistics() {
2270 ResourceMark rm;
2271 ClassStatistics::print();
2272 }
2273
2274
2275 class MethodStatistics: AllStatic {
2276 public:
2277 enum {
2278 max_parameter_size = 10
2279 };
2280 private:
2281
2282 static int _number_of_methods;
2283 static int _number_of_final_methods;
2284 static int _number_of_static_methods;
2285 static int _number_of_native_methods;
2286 static int _number_of_synchronized_methods;
2287 static int _number_of_profiled_methods;
2288 static int _number_of_bytecodes;
2289 static int _parameter_size_profile[max_parameter_size];
2290 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2291
2292 static void initialize() {
2293 _number_of_methods = 0;
2294 _number_of_final_methods = 0;
2295 _number_of_static_methods = 0;
2296 _number_of_native_methods = 0;
2297 _number_of_synchronized_methods = 0;
2298 _number_of_profiled_methods = 0;
2299 _number_of_bytecodes = 0;
2300 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2301 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2302 };
2303
2304 static void do_method(methodOop m) {
2305 _number_of_methods++;
2306 // collect flag info
2307 if (m->is_final() ) _number_of_final_methods++;
2308 if (m->is_static() ) _number_of_static_methods++;
2309 if (m->is_native() ) _number_of_native_methods++;
2310 if (m->is_synchronized()) _number_of_synchronized_methods++;
2311 if (m->method_data() != NULL) _number_of_profiled_methods++;
2312 // collect parameter size info (add one for receiver, if any)
2313 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2314 // collect bytecodes info
2315 {
2316 Thread *thread = Thread::current();
2317 HandleMark hm(thread);
2318 BytecodeStream s(methodHandle(thread, m));
2319 Bytecodes::Code c;
2320 while ((c = s.next()) >= 0) {
2321 _number_of_bytecodes++;
2322 _bytecodes_profile[c]++;
2323 }
2324 }
2325 }
2326
2327 public:
2328 static void print() {
2329 initialize();
2330 SystemDictionary::methods_do(do_method);
2331 // generate output
2332 tty->cr();
2333 tty->print_cr("Method statistics (static):");
2334 // flag distribution
2335 tty->cr();
2336 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2337 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2338 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2339 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2340 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2341 // parameter size profile
2342 tty->cr();
2343 { int tot = 0;
2344 int avg = 0;
2345 for (int i = 0; i < max_parameter_size; i++) {
2346 int n = _parameter_size_profile[i];
2347 tot += n;
2348 avg += n*i;
2349 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2350 }
2351 assert(tot == _number_of_methods, "should be the same");
2352 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2353 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2354 }
2355 // bytecodes profile
2356 tty->cr();
2357 { int tot = 0;
2358 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2359 if (Bytecodes::is_defined(i)) {
2360 Bytecodes::Code c = Bytecodes::cast(i);
2361 int n = _bytecodes_profile[c];
2362 tot += n;
2363 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2364 }
2365 }
2366 assert(tot == _number_of_bytecodes, "should be the same");
2367 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2368 }
2369 tty->cr();
2370 }
2371 };
2372
2373 int MethodStatistics::_number_of_methods;
2374 int MethodStatistics::_number_of_final_methods;
2375 int MethodStatistics::_number_of_static_methods;
2376 int MethodStatistics::_number_of_native_methods;
2377 int MethodStatistics::_number_of_synchronized_methods;
2378 int MethodStatistics::_number_of_profiled_methods;
2379 int MethodStatistics::_number_of_bytecodes;
2380 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2381 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2382
2383
2384 void SystemDictionary::print_method_statistics() {
2385 MethodStatistics::print();
2386 }
2387
2388 #endif // PRODUCT