Wed, 09 Apr 2008 15:10:22 -0700
Merge
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 */
25 # include "incls/_precompiled.incl"
26 # include "incls/_systemDictionary.cpp.incl"
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;
36 int SystemDictionary::_number_of_modifications = 0;
38 oop SystemDictionary::_system_loader_lock_obj = NULL;
40 klassOop SystemDictionary::_object_klass = NULL;
41 klassOop SystemDictionary::_string_klass = NULL;
42 klassOop SystemDictionary::_class_klass = NULL;
43 klassOop SystemDictionary::_cloneable_klass = NULL;
44 klassOop SystemDictionary::_classloader_klass = NULL;
45 klassOop SystemDictionary::_serializable_klass = NULL;
46 klassOop SystemDictionary::_system_klass = NULL;
48 klassOop SystemDictionary::_throwable_klass = NULL;
49 klassOop SystemDictionary::_error_klass = NULL;
50 klassOop SystemDictionary::_threaddeath_klass = NULL;
51 klassOop SystemDictionary::_exception_klass = NULL;
52 klassOop SystemDictionary::_runtime_exception_klass = NULL;
53 klassOop SystemDictionary::_classNotFoundException_klass = NULL;
54 klassOop SystemDictionary::_noClassDefFoundError_klass = NULL;
55 klassOop SystemDictionary::_linkageError_klass = NULL;
56 klassOop SystemDictionary::_classCastException_klass = NULL;
57 klassOop SystemDictionary::_arrayStoreException_klass = NULL;
58 klassOop SystemDictionary::_virtualMachineError_klass = NULL;
59 klassOop SystemDictionary::_outOfMemoryError_klass = NULL;
60 klassOop SystemDictionary::_StackOverflowError_klass = NULL;
61 klassOop SystemDictionary::_illegalMonitorStateException_klass = NULL;
62 klassOop SystemDictionary::_protectionDomain_klass = NULL;
63 klassOop SystemDictionary::_AccessControlContext_klass = NULL;
65 klassOop SystemDictionary::_reference_klass = NULL;
66 klassOop SystemDictionary::_soft_reference_klass = NULL;
67 klassOop SystemDictionary::_weak_reference_klass = NULL;
68 klassOop SystemDictionary::_final_reference_klass = NULL;
69 klassOop SystemDictionary::_phantom_reference_klass = NULL;
70 klassOop SystemDictionary::_finalizer_klass = NULL;
72 klassOop SystemDictionary::_thread_klass = NULL;
73 klassOop SystemDictionary::_threadGroup_klass = NULL;
74 klassOop SystemDictionary::_properties_klass = NULL;
75 klassOop SystemDictionary::_reflect_accessible_object_klass = NULL;
76 klassOop SystemDictionary::_reflect_field_klass = NULL;
77 klassOop SystemDictionary::_reflect_method_klass = NULL;
78 klassOop SystemDictionary::_reflect_constructor_klass = NULL;
79 klassOop SystemDictionary::_reflect_magic_klass = NULL;
80 klassOop SystemDictionary::_reflect_method_accessor_klass = NULL;
81 klassOop SystemDictionary::_reflect_constructor_accessor_klass = NULL;
82 klassOop SystemDictionary::_reflect_delegating_classloader_klass = NULL;
83 klassOop SystemDictionary::_reflect_constant_pool_klass = NULL;
84 klassOop SystemDictionary::_reflect_unsafe_static_field_accessor_impl_klass = NULL;
86 klassOop SystemDictionary::_vector_klass = NULL;
87 klassOop SystemDictionary::_hashtable_klass = NULL;
88 klassOop SystemDictionary::_stringBuffer_klass = NULL;
90 klassOop SystemDictionary::_stackTraceElement_klass = NULL;
92 klassOop SystemDictionary::_java_nio_Buffer_klass = NULL;
94 klassOop SystemDictionary::_sun_misc_AtomicLongCSImpl_klass = NULL;
95 klassOop SystemDictionary::_sun_jkernel_DownloadManager_klass = NULL;
97 klassOop SystemDictionary::_boolean_klass = NULL;
98 klassOop SystemDictionary::_char_klass = NULL;
99 klassOop SystemDictionary::_float_klass = NULL;
100 klassOop SystemDictionary::_double_klass = NULL;
101 klassOop SystemDictionary::_byte_klass = NULL;
102 klassOop SystemDictionary::_short_klass = NULL;
103 klassOop SystemDictionary::_int_klass = NULL;
104 klassOop SystemDictionary::_long_klass = NULL;
105 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107 oop SystemDictionary::_java_system_loader = NULL;
109 bool SystemDictionary::_has_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
112 // lazily initialized klass variables
113 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
116 // ----------------------------------------------------------------------------
117 // Java-level SystemLoader
119 oop SystemDictionary::java_system_loader() {
120 return _java_system_loader;
121 }
123 void SystemDictionary::compute_java_system_loader(TRAPS) {
124 KlassHandle system_klass(THREAD, _classloader_klass);
125 JavaValue result(T_OBJECT);
126 JavaCalls::call_static(&result,
127 KlassHandle(THREAD, _classloader_klass),
128 vmSymbolHandles::getSystemClassLoader_name(),
129 vmSymbolHandles::void_classloader_signature(),
130 CHECK);
132 _java_system_loader = (oop)result.get_jobject();
133 }
136 // ----------------------------------------------------------------------------
137 // debugging
139 #ifdef ASSERT
141 // return true if class_name contains no '.' (internal format is '/')
142 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
143 if (class_name.not_null()) {
144 ResourceMark rm;
145 char* name = class_name->as_C_string();
146 return strchr(name, '.') == NULL;
147 } else {
148 return true;
149 }
150 }
152 #endif
154 // ----------------------------------------------------------------------------
155 // Resolving of classes
157 // Forwards to resolve_or_null
159 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
160 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
161 if (HAS_PENDING_EXCEPTION || klass == NULL) {
162 KlassHandle k_h(THREAD, klass);
163 // can return a null klass
164 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
165 }
166 return klass;
167 }
169 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
170 if (HAS_PENDING_EXCEPTION) {
171 // If we have a pending exception we forward it to the caller, unless throw_error is true,
172 // in which case we have to check whether the pending exception is a ClassNotFoundException,
173 // and if so convert it to a NoClassDefFoundError
174 // And chain the original ClassNotFoundException
175 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
176 ResourceMark rm(THREAD);
177 assert(klass_h() == NULL, "Should not have result with exception pending");
178 Handle e(THREAD, PENDING_EXCEPTION);
179 CLEAR_PENDING_EXCEPTION;
180 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
181 } else {
182 return NULL;
183 }
184 }
185 // Class not found, throw appropriate error or exception depending on value of throw_error
186 if (klass_h() == NULL) {
187 ResourceMark rm(THREAD);
188 if (throw_error) {
189 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
190 } else {
191 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
192 }
193 }
194 return (klassOop)klass_h();
195 }
198 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
199 bool throw_error, TRAPS)
200 {
201 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
202 }
205 // Forwards to resolve_instance_class_or_null
207 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
208 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
209 if (FieldType::is_array(class_name())) {
210 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
211 } else {
212 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
213 }
214 }
216 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
217 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
218 }
220 // Forwards to resolve_instance_class_or_null
222 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
223 Handle class_loader,
224 Handle protection_domain,
225 TRAPS) {
226 assert(FieldType::is_array(class_name()), "must be array");
227 jint dimension;
228 symbolOop object_key;
229 klassOop k = NULL;
230 // dimension and object_key are assigned as a side-effect of this call
231 BasicType t = FieldType::get_array_info(class_name(),
232 &dimension,
233 &object_key,
234 CHECK_NULL);
236 if (t == T_OBJECT) {
237 symbolHandle h_key(THREAD, object_key);
238 // naked oop "k" is OK here -- we assign back into it
239 k = SystemDictionary::resolve_instance_class_or_null(h_key,
240 class_loader,
241 protection_domain,
242 CHECK_NULL);
243 if (k != NULL) {
244 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
245 }
246 } else {
247 k = Universe::typeArrayKlassObj(t);
248 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
249 }
250 return k;
251 }
254 // Must be called for any super-class or super-interface resolution
255 // during class definition to allow class circularity checking
256 // super-interface callers:
257 // parse_interfaces - for defineClass & jvmtiRedefineClasses
258 // super-class callers:
259 // ClassFileParser - for defineClass & jvmtiRedefineClasses
260 // load_shared_class - while loading a class from shared archive
261 // resolve_instance_class_or_fail:
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
289 symbolHandle class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
295 // Double-check, if child class is already loaded, just return super-class,interface
296 // Don't add a placedholder if already loaded, i.e. already in system dictionary
297 // Make sure there's a placeholder for the *child* before resolving.
298 // Used as a claim that this thread is currently loading superclass/classloader
299 // Used here for ClassCircularity checks and also for heap verification
300 // (every instanceKlass in the heap needs to be in the system dictionary
301 // or have a placeholder).
302 // Must check ClassCircularity before checking if super class is already loaded
303 //
304 // We might not already have a placeholder if this child_name was
305 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
306 // the name of the class might not be known until the stream is actually
307 // parsed.
308 // Bugs 4643874, 4715493
309 // compute_hash can have a safepoint
311 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
312 int d_index = dictionary()->hash_to_index(d_hash);
313 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
314 int p_index = placeholders()->hash_to_index(p_hash);
315 // can't throw error holding a lock
316 bool child_already_loaded = false;
317 bool throw_circularity_error = false;
318 {
319 MutexLocker mu(SystemDictionary_lock, THREAD);
320 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
321 klassOop quicksuperk;
322 // to support // loading: if child done loading, just return superclass
323 // if class_name, & class_loader don't match:
324 // if initial define, SD update will give LinkageError
325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
326 // so we don't throw an exception here.
327 // see: nsk redefclass014 & java.lang.instrument Instrument032
328 if ((childk != NULL ) && (is_superclass) &&
329 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
331 ((Klass::cast(quicksuperk)->name() == class_name()) &&
332 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
333 return quicksuperk;
334 } else {
335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
337 throw_circularity_error = true;
338 }
340 // add placeholder entry even if error - callers will remove on error
341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
342 if (throw_circularity_error) {
343 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
344 }
345 }
346 }
347 if (throw_circularity_error) {
348 ResourceMark rm(THREAD);
349 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
350 }
352 // java.lang.Object should have been found above
353 assert(class_name() != NULL, "null super class for resolving");
354 // Resolve the super class or interface, check results on return
355 klassOop superk = NULL;
356 superk = SystemDictionary::resolve_or_null(class_name,
357 class_loader,
358 protection_domain,
359 THREAD);
361 KlassHandle superk_h(THREAD, superk);
363 // Note: clean up of placeholders currently in callers of
364 // resolve_super_or_fail - either at update_dictionary time
365 // or on error
366 {
367 MutexLocker mu(SystemDictionary_lock, THREAD);
368 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
369 if (probe != NULL) {
370 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
371 }
372 }
373 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
374 // can null superk
375 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
376 }
378 return superk_h();
379 }
382 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
383 Handle class_loader,
384 Handle protection_domain,
385 TRAPS) {
386 if(!has_checkPackageAccess()) return;
388 // Now we have to call back to java to check if the initating class has access
389 JavaValue result(T_VOID);
390 if (TraceProtectionDomainVerification) {
391 // Print out trace information
392 tty->print_cr("Checking package access");
393 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
394 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
395 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
396 }
398 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
400 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
401 JavaCalls::call_special(&result,
402 class_loader,
403 system_loader,
404 vmSymbolHandles::checkPackageAccess_name(),
405 vmSymbolHandles::class_protectiondomain_signature(),
406 Handle(THREAD, klass->java_mirror()),
407 protection_domain,
408 THREAD);
410 if (TraceProtectionDomainVerification) {
411 if (HAS_PENDING_EXCEPTION) {
412 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
413 } else {
414 tty->print_cr(" -> granted");
415 }
416 tty->cr();
417 }
419 if (HAS_PENDING_EXCEPTION) return;
421 // If no exception has been thrown, we have validated the protection domain
422 // Insert the protection domain of the initiating class into the set.
423 {
424 // We recalculate the entry here -- we've called out to java since
425 // the last time it was calculated.
426 symbolHandle kn(THREAD, klass->name());
427 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
428 int d_index = dictionary()->hash_to_index(d_hash);
430 MutexLocker mu(SystemDictionary_lock, THREAD);
431 {
432 // Note that we have an entry, and entries can be deleted only during GC,
433 // so we cannot allow GC to occur while we're holding this entry.
435 // We're using a No_Safepoint_Verifier to catch any place where we
436 // might potentially do a GC at all.
437 // SystemDictionary::do_unloading() asserts that classes are only
438 // unloaded at a safepoint.
439 No_Safepoint_Verifier nosafepoint;
440 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
441 protection_domain, THREAD);
442 }
443 }
444 }
446 // We only get here if this thread finds that another thread
447 // has already claimed the placeholder token for the current operation,
448 // but that other thread either never owned or gave up the
449 // object lock
450 // Waits on SystemDictionary_lock to indicate placeholder table updated
451 // On return, caller must recheck placeholder table state
452 //
453 // We only get here if
454 // 1) custom classLoader, i.e. not bootstrap classloader
455 // 2) UnsyncloadClass not set
456 // 3) custom classLoader has broken the class loader objectLock
457 // so another thread got here in parallel
458 //
459 // lockObject must be held.
460 // Complicated dance due to lock ordering:
461 // Must first release the classloader object lock to
462 // allow initial definer to complete the class definition
463 // and to avoid deadlock
464 // Reclaim classloader lock object with same original recursion count
465 // Must release SystemDictionary_lock after notify, since
466 // class loader lock must be claimed before SystemDictionary_lock
467 // to prevent deadlocks
468 //
469 // The notify allows applications that did an untimed wait() on
470 // the classloader object lock to not hang.
471 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
472 assert_lock_strong(SystemDictionary_lock);
474 bool calledholdinglock
475 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
476 assert(calledholdinglock,"must hold lock for notify");
477 assert(!UnsyncloadClass, "unexpected double_lock_wait");
478 ObjectSynchronizer::notifyall(lockObject, THREAD);
479 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
480 SystemDictionary_lock->wait();
481 SystemDictionary_lock->unlock();
482 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
483 SystemDictionary_lock->lock();
484 }
486 // If the class in is in the placeholder table, class loading is in progress
487 // For cases where the application changes threads to load classes, it
488 // is critical to ClassCircularity detection that we try loading
489 // the superclass on the same thread internally, so we do parallel
490 // super class loading here.
491 // This also is critical in cases where the original thread gets stalled
492 // even in non-circularity situations.
493 // Note: only one thread can define the class, but multiple can resolve
494 // Note: must call resolve_super_or_fail even if null super -
495 // to force placeholder entry creation for this class
496 // Caller must check for pending exception
497 // Returns non-null klassOop if other thread has completed load
498 // and we are done,
499 // If return null klassOop and no pending exception, the caller must load the class
500 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
501 symbolHandle name, symbolHandle superclassname, Handle class_loader,
502 Handle protection_domain, Handle lockObject, TRAPS) {
504 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
505 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
506 int d_index = dictionary()->hash_to_index(d_hash);
507 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
508 int p_index = placeholders()->hash_to_index(p_hash);
510 // superk is not used, resolve_super called for circularity check only
511 // This code is reached in two situations. One if this thread
512 // is loading the same class twice (e.g. ClassCircularity, or
513 // java.lang.instrument).
514 // The second is if another thread started the resolve_super first
515 // and has not yet finished.
516 // In both cases the original caller will clean up the placeholder
517 // entry on error.
518 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
519 superclassname,
520 class_loader,
521 protection_domain,
522 true,
523 CHECK_(nh));
524 // We don't redefine the class, so we just need to clean up if there
525 // was not an error (don't want to modify any system dictionary
526 // data structures).
527 {
528 MutexLocker mu(SystemDictionary_lock, THREAD);
529 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
530 SystemDictionary_lock->notify_all();
531 }
533 // UnsyncloadClass does NOT wait for parallel superclass loads to complete
534 // Bootstrap classloader does wait for parallel superclass loads
535 if (UnsyncloadClass) {
536 MutexLocker mu(SystemDictionary_lock, THREAD);
537 // Check if classloading completed while we were loading superclass or waiting
538 klassOop check = find_class(d_index, d_hash, name, class_loader);
539 if (check != NULL) {
540 // Klass is already loaded, so just return it
541 return(instanceKlassHandle(THREAD, check));
542 } else {
543 return nh;
544 }
545 }
547 // must loop to both handle other placeholder updates
548 // and spurious notifications
549 bool super_load_in_progress = true;
550 PlaceholderEntry* placeholder;
551 while (super_load_in_progress) {
552 MutexLocker mu(SystemDictionary_lock, THREAD);
553 // Check if classloading completed while we were loading superclass or waiting
554 klassOop check = find_class(d_index, d_hash, name, class_loader);
555 if (check != NULL) {
556 // Klass is already loaded, so just return it
557 return(instanceKlassHandle(THREAD, check));
558 } else {
559 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
560 if (placeholder && placeholder->super_load_in_progress() ){
561 // Before UnsyncloadClass:
562 // We only get here if the application has released the
563 // classloader lock when another thread was in the middle of loading a
564 // superclass/superinterface for this class, and now
565 // this thread is also trying to load this class.
566 // To minimize surprises, the first thread that started to
567 // load a class should be the one to complete the loading
568 // with the classfile it initially expected.
569 // This logic has the current thread wait once it has done
570 // all the superclass/superinterface loading it can, until
571 // the original thread completes the class loading or fails
572 // If it completes we will use the resulting instanceKlass
573 // which we will find below in the systemDictionary.
574 // We also get here for parallel bootstrap classloader
575 if (class_loader.is_null()) {
576 SystemDictionary_lock->wait();
577 } else {
578 double_lock_wait(lockObject, THREAD);
579 }
580 } else {
581 // If not in SD and not in PH, other thread's load must have failed
582 super_load_in_progress = false;
583 }
584 }
585 }
586 return (nh);
587 }
590 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
591 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
592 // First check to see if we should remove wrapping L and ;
593 symbolHandle name;
594 if (FieldType::is_obj(class_name())) {
595 ResourceMark rm(THREAD);
596 // Ignore wrapping L and ;.
597 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
598 } else {
599 name = class_name;
600 }
602 // UseNewReflection
603 // Fix for 4474172; see evaluation for more details
604 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
606 // Do lookup to see if class already exist and the protection domain
607 // has the right access
608 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
609 int d_index = dictionary()->hash_to_index(d_hash);
610 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
611 protection_domain, THREAD);
612 if (probe != NULL) return probe;
615 // Non-bootstrap class loaders will call out to class loader and
616 // define via jvm/jni_DefineClass which will acquire the
617 // class loader object lock to protect against multiple threads
618 // defining the class in parallel by accident.
619 // This lock must be acquired here so the waiter will find
620 // any successful result in the SystemDictionary and not attempt
621 // the define
622 // Classloaders that support parallelism, e.g. bootstrap classloader,
623 // or all classloaders with UnsyncloadClass do not acquire lock here
624 bool DoObjectLock = true;
625 if (UnsyncloadClass || (class_loader.is_null())) {
626 DoObjectLock = false;
627 }
629 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
630 int p_index = placeholders()->hash_to_index(p_hash);
632 // Class is not in SystemDictionary so we have to do loading.
633 // Make sure we are synchronized on the class loader before we proceed
634 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
635 check_loader_lock_contention(lockObject, THREAD);
636 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
638 // Check again (after locking) if class already exist in SystemDictionary
639 bool class_has_been_loaded = false;
640 bool super_load_in_progress = false;
641 bool havesupername = false;
642 instanceKlassHandle k;
643 PlaceholderEntry* placeholder;
644 symbolHandle superclassname;
646 {
647 MutexLocker mu(SystemDictionary_lock, THREAD);
648 klassOop check = find_class(d_index, d_hash, name, class_loader);
649 if (check != NULL) {
650 // Klass is already loaded, so just return it
651 class_has_been_loaded = true;
652 k = instanceKlassHandle(THREAD, check);
653 } else {
654 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
655 if (placeholder && placeholder->super_load_in_progress()) {
656 super_load_in_progress = true;
657 if (placeholder->havesupername() == true) {
658 superclassname = symbolHandle(THREAD, placeholder->supername());
659 havesupername = true;
660 }
661 }
662 }
663 }
665 // If the class in is in the placeholder table, class loading is in progress
666 if (super_load_in_progress && havesupername==true) {
667 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
668 class_loader, protection_domain, lockObject, THREAD);
669 if (HAS_PENDING_EXCEPTION) {
670 return NULL;
671 }
672 if (!k.is_null()) {
673 class_has_been_loaded = true;
674 }
675 }
677 if (!class_has_been_loaded) {
679 // add placeholder entry to record loading instance class
680 // Five cases:
681 // All cases need to prevent modifying bootclasssearchpath
682 // in parallel with a classload of same classname
683 // case 1. traditional classloaders that rely on the classloader object lock
684 // - no other need for LOAD_INSTANCE
685 // case 2. traditional classloaders that break the classloader object lock
686 // as a deadlock workaround. Detection of this case requires that
687 // this check is done while holding the classloader object lock,
688 // and that lock is still held when calling classloader's loadClass.
689 // For these classloaders, we ensure that the first requestor
690 // completes the load and other requestors wait for completion.
691 // case 3. UnsyncloadClass - don't use objectLocker
692 // With this flag, we allow parallel classloading of a
693 // class/classloader pair
694 // case4. Bootstrap classloader - don't own objectLocker
695 // This classloader supports parallelism at the classloader level,
696 // but only allows a single load of a class/classloader pair.
697 // No performance benefit and no deadlock issues.
698 // case 5. Future: parallel user level classloaders - without objectLocker
699 symbolHandle nullsymbolHandle;
700 bool throw_circularity_error = false;
701 {
702 MutexLocker mu(SystemDictionary_lock, THREAD);
703 if (!UnsyncloadClass) {
704 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
705 if (oldprobe) {
706 // only need check_seen_thread once, not on each loop
707 // 6341374 java/lang/Instrument with -Xcomp
708 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
709 throw_circularity_error = true;
710 } else {
711 // case 1: traditional: should never see load_in_progress.
712 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
714 // case 4: bootstrap classloader: prevent futile classloading,
715 // wait on first requestor
716 if (class_loader.is_null()) {
717 SystemDictionary_lock->wait();
718 } else {
719 // case 2: traditional with broken classloader lock. wait on first
720 // requestor.
721 double_lock_wait(lockObject, THREAD);
722 }
723 // Check if classloading completed while we were waiting
724 klassOop check = find_class(d_index, d_hash, name, class_loader);
725 if (check != NULL) {
726 // Klass is already loaded, so just return it
727 k = instanceKlassHandle(THREAD, check);
728 class_has_been_loaded = true;
729 }
730 // check if other thread failed to load and cleaned up
731 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
732 }
733 }
734 }
735 }
736 // All cases: add LOAD_INSTANCE
737 // case 3: UnsyncloadClass: allow competing threads to try
738 // LOAD_INSTANCE in parallel
739 // add placeholder entry even if error - callers will remove on error
740 if (!class_has_been_loaded) {
741 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
742 if (throw_circularity_error) {
743 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
744 }
745 // For class loaders that do not acquire the classloader object lock,
746 // if they did not catch another thread holding LOAD_INSTANCE,
747 // need a check analogous to the acquire ObjectLocker/find_class
748 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
749 // one final check if the load has already completed
750 klassOop check = find_class(d_index, d_hash, name, class_loader);
751 if (check != NULL) {
752 // Klass is already loaded, so just return it
753 k = instanceKlassHandle(THREAD, check);
754 class_has_been_loaded = true;
755 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
756 }
757 }
758 }
759 // must throw error outside of owning lock
760 if (throw_circularity_error) {
761 ResourceMark rm(THREAD);
762 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
763 }
765 if (!class_has_been_loaded) {
767 // Do actual loading
768 k = load_instance_class(name, class_loader, THREAD);
770 // In custom class loaders, the usual findClass calls
771 // findLoadedClass, which directly searches the SystemDictionary, then
772 // defineClass. If these are not atomic with respect to other threads,
773 // the findLoadedClass can fail, but the defineClass can get a
774 // LinkageError:: duplicate class definition.
775 // If they got a linkageError, check if a parallel class load succeeded.
776 // If it did, then for bytecode resolution the specification requires
777 // that we return the same result we did for the other thread, i.e. the
778 // successfully loaded instanceKlass
779 // Note: Class can not be unloaded as long as any classloader refs exist
780 // Should not get here for classloaders that support parallelism
781 // with the new cleaner mechanism, e.g. bootstrap classloader
782 if (UnsyncloadClass || (class_loader.is_null())) {
783 if (k.is_null() && HAS_PENDING_EXCEPTION
784 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
785 MutexLocker mu(SystemDictionary_lock, THREAD);
786 klassOop check = find_class(d_index, d_hash, name, class_loader);
787 if (check != NULL) {
788 // Klass is already loaded, so just use it
789 k = instanceKlassHandle(THREAD, check);
790 CLEAR_PENDING_EXCEPTION;
791 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
792 }
793 }
794 }
796 // clean up placeholder entries for success or error
797 // This cleans up LOAD_INSTANCE entries
798 // It also cleans up LOAD_SUPER entries on errors from
799 // calling load_instance_class
800 {
801 MutexLocker mu(SystemDictionary_lock, THREAD);
802 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
803 if (probe != NULL) {
804 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
805 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
806 SystemDictionary_lock->notify_all();
807 }
808 }
810 // If everything was OK (no exceptions, no null return value), and
811 // class_loader is NOT the defining loader, do a little more bookkeeping.
812 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
813 k->class_loader() != class_loader()) {
815 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
817 // Need to check for a PENDING_EXCEPTION again; check_constraints
818 // can throw and doesn't use the CHECK macro.
819 if (!HAS_PENDING_EXCEPTION) {
820 { // Grabbing the Compile_lock prevents systemDictionary updates
821 // during compilations.
822 MutexLocker mu(Compile_lock, THREAD);
823 update_dictionary(d_index, d_hash, p_index, p_hash,
824 k, class_loader, THREAD);
825 }
826 if (JvmtiExport::should_post_class_load()) {
827 Thread *thread = THREAD;
828 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
829 JvmtiExport::post_class_load((JavaThread *) thread, k());
830 }
831 }
832 }
833 if (HAS_PENDING_EXCEPTION || k.is_null()) {
834 // On error, clean up placeholders
835 {
836 MutexLocker mu(SystemDictionary_lock, THREAD);
837 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
838 SystemDictionary_lock->notify_all();
839 }
840 return NULL;
841 }
842 }
843 }
845 #ifdef ASSERT
846 {
847 Handle loader (THREAD, k->class_loader());
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 oop kk = find_class_or_placeholder(name, loader);
850 assert(kk == k(), "should be present in dictionary");
851 }
852 #endif
854 // return if the protection domain in NULL
855 if (protection_domain() == NULL) return k();
857 // Check the protection domain has the right access
858 {
859 MutexLocker mu(SystemDictionary_lock, THREAD);
860 // Note that we have an entry, and entries can be deleted only during GC,
861 // so we cannot allow GC to occur while we're holding this entry.
862 // We're using a No_Safepoint_Verifier to catch any place where we
863 // might potentially do a GC at all.
864 // SystemDictionary::do_unloading() asserts that classes are only
865 // unloaded at a safepoint.
866 No_Safepoint_Verifier nosafepoint;
867 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
868 class_loader,
869 protection_domain)) {
870 return k();
871 }
872 }
874 // Verify protection domain. If it fails an exception is thrown
875 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
877 return k();
878 }
881 // This routine does not lock the system dictionary.
882 //
883 // Since readers don't hold a lock, we must make sure that system
884 // dictionary entries are only removed at a safepoint (when only one
885 // thread is running), and are added to in a safe way (all links must
886 // be updated in an MT-safe manner).
887 //
888 // Callers should be aware that an entry could be added just after
889 // _dictionary->bucket(index) is read here, so the caller will not see
890 // the new entry.
892 klassOop SystemDictionary::find(symbolHandle class_name,
893 Handle class_loader,
894 Handle protection_domain,
895 TRAPS) {
897 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
898 int d_index = dictionary()->hash_to_index(d_hash);
900 {
901 // Note that we have an entry, and entries can be deleted only during GC,
902 // so we cannot allow GC to occur while we're holding this entry.
903 // We're using a No_Safepoint_Verifier to catch any place where we
904 // might potentially do a GC at all.
905 // SystemDictionary::do_unloading() asserts that classes are only
906 // unloaded at a safepoint.
907 No_Safepoint_Verifier nosafepoint;
908 return dictionary()->find(d_index, d_hash, class_name, class_loader,
909 protection_domain, THREAD);
910 }
911 }
914 // Look for a loaded instance or array klass by name. Do not do any loading.
915 // return NULL in case of error.
916 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
917 Handle class_loader,
918 Handle protection_domain,
919 TRAPS) {
920 klassOop k = NULL;
921 assert(class_name() != NULL, "class name must be non NULL");
922 if (FieldType::is_array(class_name())) {
923 // The name refers to an array. Parse the name.
924 jint dimension;
925 symbolOop object_key;
927 // dimension and object_key are assigned as a side-effect of this call
928 BasicType t = FieldType::get_array_info(class_name(), &dimension,
929 &object_key, CHECK_(NULL));
930 if (t != T_OBJECT) {
931 k = Universe::typeArrayKlassObj(t);
932 } else {
933 symbolHandle h_key(THREAD, object_key);
934 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
935 }
936 if (k != NULL) {
937 k = Klass::cast(k)->array_klass_or_null(dimension);
938 }
939 } else {
940 k = find(class_name, class_loader, protection_domain, THREAD);
941 }
942 return k;
943 }
945 // Note: this method is much like resolve_from_stream, but
946 // updates no supplemental data structures.
947 // TODO consolidate the two methods with a helper routine?
948 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 ClassFileStream* st,
952 TRAPS) {
953 symbolHandle parsed_name;
955 // Parse the stream. Note that we do this even though this klass might
956 // already be present in the SystemDictionary, otherwise we would not
957 // throw potential ClassFormatErrors.
958 //
959 // Note: "name" is updated.
960 // Further note: a placeholder will be added for this class when
961 // super classes are loaded (resolve_super_or_fail). We expect this
962 // to be called for all classes but java.lang.Object; and we preload
963 // java.lang.Object through resolve_or_fail, not this path.
965 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
966 class_loader,
967 protection_domain,
968 parsed_name,
969 THREAD);
972 // We don't redefine the class, so we just need to clean up whether there
973 // was an error or not (don't want to modify any system dictionary
974 // data structures).
975 // Parsed name could be null if we threw an error before we got far
976 // enough along to parse it -- in that case, there is nothing to clean up.
977 if (!parsed_name.is_null()) {
978 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
979 class_loader);
980 int p_index = placeholders()->hash_to_index(p_hash);
981 {
982 MutexLocker mu(SystemDictionary_lock, THREAD);
983 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
984 SystemDictionary_lock->notify_all();
985 }
986 }
988 return k();
989 }
991 // Add a klass to the system from a stream (called by jni_DefineClass and
992 // JVM_DefineClass).
993 // Note: class_name can be NULL. In that case we do not know the name of
994 // the class until we have parsed the stream.
996 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
997 Handle class_loader,
998 Handle protection_domain,
999 ClassFileStream* st,
1000 TRAPS) {
1002 // Make sure we are synchronized on the class loader before we initiate
1003 // loading.
1004 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1005 check_loader_lock_contention(lockObject, THREAD);
1006 ObjectLocker ol(lockObject, THREAD);
1008 symbolHandle parsed_name;
1010 // Parse the stream. Note that we do this even though this klass might
1011 // already be present in the SystemDictionary, otherwise we would not
1012 // throw potential ClassFormatErrors.
1013 //
1014 // Note: "name" is updated.
1015 // Further note: a placeholder will be added for this class when
1016 // super classes are loaded (resolve_super_or_fail). We expect this
1017 // to be called for all classes but java.lang.Object; and we preload
1018 // java.lang.Object through resolve_or_fail, not this path.
1020 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1021 class_loader,
1022 protection_domain,
1023 parsed_name,
1024 THREAD);
1026 const char* pkg = "java/";
1027 if (!HAS_PENDING_EXCEPTION &&
1028 !class_loader.is_null() &&
1029 !parsed_name.is_null() &&
1030 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1031 // It is illegal to define classes in the "java." package from
1032 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1033 ResourceMark rm(THREAD);
1034 char* name = parsed_name->as_C_string();
1035 char* index = strrchr(name, '/');
1036 *index = '\0'; // chop to just the package name
1037 while ((index = strchr(name, '/')) != NULL) {
1038 *index = '.'; // replace '/' with '.' in package name
1039 }
1040 const char* fmt = "Prohibited package name: %s";
1041 size_t len = strlen(fmt) + strlen(name);
1042 char* message = NEW_RESOURCE_ARRAY(char, len);
1043 jio_snprintf(message, len, fmt, name);
1044 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1045 vmSymbols::java_lang_SecurityException(), message);
1046 }
1048 if (!HAS_PENDING_EXCEPTION) {
1049 assert(!parsed_name.is_null(), "Sanity");
1050 assert(class_name.is_null() || class_name() == parsed_name(),
1051 "name mismatch");
1052 // Verification prevents us from creating names with dots in them, this
1053 // asserts that that's the case.
1054 assert(is_internal_format(parsed_name),
1055 "external class name format used internally");
1057 // Add class just loaded
1058 define_instance_class(k, THREAD);
1059 }
1061 // If parsing the class file or define_instance_class failed, we
1062 // need to remove the placeholder added on our behalf. But we
1063 // must make sure parsed_name is valid first (it won't be if we had
1064 // a format error before the class was parsed far enough to
1065 // find the name).
1066 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1067 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1068 class_loader);
1069 int p_index = placeholders()->hash_to_index(p_hash);
1070 {
1071 MutexLocker mu(SystemDictionary_lock, THREAD);
1072 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1073 SystemDictionary_lock->notify_all();
1074 }
1075 return NULL;
1076 }
1078 // Make sure that we didn't leave a place holder in the
1079 // SystemDictionary; this is only done on success
1080 debug_only( {
1081 if (!HAS_PENDING_EXCEPTION) {
1082 assert(!parsed_name.is_null(), "parsed_name is still null?");
1083 symbolHandle h_name (THREAD, k->name());
1084 Handle h_loader (THREAD, k->class_loader());
1086 MutexLocker mu(SystemDictionary_lock, THREAD);
1088 oop check = find_class_or_placeholder(parsed_name, class_loader);
1089 assert(check == k(), "should be present in the dictionary");
1091 oop check2 = find_class_or_placeholder(h_name, h_loader);
1092 assert(check == check2, "name inconsistancy in SystemDictionary");
1093 }
1094 } );
1096 return k();
1097 }
1100 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1101 int number_of_entries) {
1102 assert(length == _nof_buckets * sizeof(HashtableBucket),
1103 "bad shared dictionary size.");
1104 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1105 }
1108 // If there is a shared dictionary, then find the entry for the
1109 // given shared system class, if any.
1111 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1112 if (shared_dictionary() != NULL) {
1113 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1114 int d_index = dictionary()->hash_to_index(d_hash);
1115 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1116 } else {
1117 return NULL;
1118 }
1119 }
1122 // Load a class from the shared spaces (found through the shared system
1123 // dictionary). Force the superclass and all interfaces to be loaded.
1124 // Update the class definition to include sibling classes and no
1125 // subclasses (yet). [Classes in the shared space are not part of the
1126 // object hierarchy until loaded.]
1128 instanceKlassHandle SystemDictionary::load_shared_class(
1129 symbolHandle class_name, Handle class_loader, TRAPS) {
1130 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1131 return load_shared_class(ik, class_loader, THREAD);
1132 }
1134 // Note well! Changes to this method may affect oop access order
1135 // in the shared archive. Please take care to not make changes that
1136 // adversely affect cold start time by changing the oop access order
1137 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1138 // MarkAndMoveOrderedReadWrite closures.
1139 instanceKlassHandle SystemDictionary::load_shared_class(
1140 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1141 assert(class_loader.is_null(), "non-null classloader for shared class?");
1142 if (ik.not_null()) {
1143 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1144 symbolHandle class_name(THREAD, ik->name());
1146 // Found the class, now load the superclass and interfaces. If they
1147 // are shared, add them to the main system dictionary and reset
1148 // their hierarchy references (supers, subs, and interfaces).
1150 if (ik->super() != NULL) {
1151 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1152 resolve_super_or_fail(class_name, cn,
1153 class_loader, Handle(), true, CHECK_(nh));
1154 }
1156 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1157 int num_interfaces = interfaces->length();
1158 for (int index = 0; index < num_interfaces; index++) {
1159 klassOop k = klassOop(interfaces->obj_at(index));
1161 // Note: can not use instanceKlass::cast here because
1162 // interfaces' instanceKlass's C++ vtbls haven't been
1163 // reinitialized yet (they will be once the interface classes
1164 // are loaded)
1165 symbolHandle name (THREAD, k->klass_part()->name());
1166 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1167 }
1169 // Adjust methods to recover missing data. They need addresses for
1170 // interpreter entry points and their default native method address
1171 // must be reset.
1173 // Updating methods must be done under a lock so multiple
1174 // threads don't update these in parallel
1175 // Shared classes are all currently loaded by the bootstrap
1176 // classloader, so this will never cause a deadlock on
1177 // a custom class loader lock.
1179 {
1180 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1181 check_loader_lock_contention(lockObject, THREAD);
1182 ObjectLocker ol(lockObject, THREAD, true);
1184 objArrayHandle methods (THREAD, ik->methods());
1185 int num_methods = methods->length();
1186 for (int index2 = 0; index2 < num_methods; ++index2) {
1187 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1188 m()->link_method(m, CHECK_(nh));
1189 }
1190 }
1192 if (TraceClassLoading) {
1193 ResourceMark rm;
1194 tty->print("[Loaded %s", ik->external_name());
1195 tty->print(" from shared objects file");
1196 tty->print_cr("]");
1197 }
1198 // notify a class loaded from shared object
1199 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1200 true /* shared class */);
1201 }
1202 return ik;
1203 }
1205 #ifdef KERNEL
1206 // Some classes on the bootstrap class path haven't been installed on the
1207 // system yet. Call the DownloadManager method to make them appear in the
1208 // bootstrap class path and try again to load the named class.
1209 // Note that with delegation class loaders all classes in another loader will
1210 // first try to call this so it'd better be fast!!
1211 static instanceKlassHandle download_and_retry_class_load(
1212 symbolHandle class_name,
1213 TRAPS) {
1215 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1216 instanceKlassHandle nk;
1218 // If download manager class isn't loaded just return.
1219 if (dlm == NULL) return nk;
1221 { HandleMark hm(THREAD);
1222 ResourceMark rm(THREAD);
1223 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1224 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1226 // return value
1227 JavaValue result(T_OBJECT);
1229 // Call the DownloadManager. We assume that it has a lock because
1230 // multiple classes could be not found and downloaded at the same time.
1231 // class sun.misc.DownloadManager;
1232 // public static String getBootClassPathEntryForClass(String className);
1233 JavaCalls::call_static(&result,
1234 KlassHandle(THREAD, dlm),
1235 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1236 vmSymbolHandles::string_string_signature(),
1237 class_string,
1238 CHECK_(nk));
1240 // Get result.string and add to bootclasspath
1241 assert(result.get_type() == T_OBJECT, "just checking");
1242 oop obj = (oop) result.get_jobject();
1243 if (obj == NULL) { return nk; }
1245 Handle h_obj(THREAD, obj);
1246 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1247 CHECK_(nk));
1249 // lock the loader
1250 // we use this lock because JVMTI does.
1251 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1253 ObjectLocker ol(loader_lock, THREAD);
1254 // add the file to the bootclasspath
1255 ClassLoader::update_class_path_entry_list(new_class_name, true);
1256 } // end HandleMark
1258 if (TraceClassLoading) {
1259 ClassLoader::print_bootclasspath();
1260 }
1261 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1262 }
1263 #endif // KERNEL
1266 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1267 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1268 if (class_loader.is_null()) {
1269 // Search the shared system dictionary for classes preloaded into the
1270 // shared spaces.
1271 instanceKlassHandle k;
1272 k = load_shared_class(class_name, class_loader, THREAD);
1274 if (k.is_null()) {
1275 // Use VM class loader
1276 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1277 }
1279 #ifdef KERNEL
1280 // If the VM class loader has failed to load the class, call the
1281 // DownloadManager class to make it magically appear on the classpath
1282 // and try again. This is only configured with the Kernel VM.
1283 if (k.is_null()) {
1284 k = download_and_retry_class_load(class_name, CHECK_(nh));
1285 }
1286 #endif // KERNEL
1288 // find_or_define_instance_class may return a different k
1289 if (!k.is_null()) {
1290 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1291 }
1292 return k;
1293 } else {
1294 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1295 ResourceMark rm(THREAD);
1297 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1298 // Translate to external class name format, i.e., convert '/' chars to '.'
1299 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1301 JavaValue result(T_OBJECT);
1303 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1305 // UnsyncloadClass option means don't synchronize loadClass() calls.
1306 // loadClassInternal() is synchronized and public loadClass(String) is not.
1307 // This flag is for diagnostic purposes only. It is risky to call
1308 // custom class loaders without synchronization.
1309 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1310 // findClass, this flag risks unexpected timing bugs in the field.
1311 // Do NOT assume this will be supported in future releases.
1312 if (!UnsyncloadClass && has_loadClassInternal()) {
1313 JavaCalls::call_special(&result,
1314 class_loader,
1315 spec_klass,
1316 vmSymbolHandles::loadClassInternal_name(),
1317 vmSymbolHandles::string_class_signature(),
1318 string,
1319 CHECK_(nh));
1320 } else {
1321 JavaCalls::call_virtual(&result,
1322 class_loader,
1323 spec_klass,
1324 vmSymbolHandles::loadClass_name(),
1325 vmSymbolHandles::string_class_signature(),
1326 string,
1327 CHECK_(nh));
1328 }
1330 assert(result.get_type() == T_OBJECT, "just checking");
1331 oop obj = (oop) result.get_jobject();
1333 // Primitive classes return null since forName() can not be
1334 // used to obtain any of the Class objects representing primitives or void
1335 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1336 instanceKlassHandle k =
1337 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1338 // For user defined Java class loaders, check that the name returned is
1339 // the same as that requested. This check is done for the bootstrap
1340 // loader when parsing the class file.
1341 if (class_name() == k->name()) {
1342 return k;
1343 }
1344 }
1345 // Class is not found or has the wrong name, return NULL
1346 return nh;
1347 }
1348 }
1350 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1352 Handle class_loader_h(THREAD, k->class_loader());
1354 // for bootstrap classloader don't acquire lock
1355 if (!class_loader_h.is_null()) {
1356 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1357 compute_loader_lock_object(class_loader_h, THREAD)),
1358 "define called without lock");
1359 }
1362 // Check class-loading constraints. Throw exception if violation is detected.
1363 // Grabs and releases SystemDictionary_lock
1364 // The check_constraints/find_class call and update_dictionary sequence
1365 // must be "atomic" for a specific class/classloader pair so we never
1366 // define two different instanceKlasses for that class/classloader pair.
1367 // Existing classloaders will call define_instance_class with the
1368 // classloader lock held
1369 // Parallel classloaders will call find_or_define_instance_class
1370 // which will require a token to perform the define class
1371 symbolHandle name_h(THREAD, k->name());
1372 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1373 int d_index = dictionary()->hash_to_index(d_hash);
1374 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1376 // Register class just loaded with class loader (placed in Vector)
1377 // Note we do this before updating the dictionary, as this can
1378 // fail with an OutOfMemoryError (if it does, we will *not* put this
1379 // class in the dictionary and will not update the class hierarchy).
1380 if (k->class_loader() != NULL) {
1381 methodHandle m(THREAD, Universe::loader_addClass_method());
1382 JavaValue result(T_VOID);
1383 JavaCallArguments args(class_loader_h);
1384 args.push_oop(Handle(THREAD, k->java_mirror()));
1385 JavaCalls::call(&result, m, &args, CHECK);
1386 }
1388 // Add the new class. We need recompile lock during update of CHA.
1389 {
1390 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1391 int p_index = placeholders()->hash_to_index(p_hash);
1393 MutexLocker mu_r(Compile_lock, THREAD);
1395 // Add to class hierarchy, initialize vtables, and do possible
1396 // deoptimizations.
1397 add_to_hierarchy(k, CHECK); // No exception, but can block
1399 // Add to systemDictionary - so other classes can see it.
1400 // Grabs and releases SystemDictionary_lock
1401 update_dictionary(d_index, d_hash, p_index, p_hash,
1402 k, class_loader_h, THREAD);
1403 }
1404 k->eager_initialize(THREAD);
1406 // notify jvmti
1407 if (JvmtiExport::should_post_class_load()) {
1408 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1409 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1411 }
1412 }
1414 // Support parallel classloading
1415 // Initial implementation for bootstrap classloader
1416 // For future:
1417 // For custom class loaders that support parallel classloading,
1418 // in case they do not synchronize around
1419 // FindLoadedClass/DefineClass calls, we check for parallel
1420 // loading for them, wait if a defineClass is in progress
1421 // and return the initial requestor's results
1422 // For better performance, the class loaders should synchronize
1423 // findClass(), i.e. FindLoadedClass/DefineClass or they
1424 // potentially waste time reading and parsing the bytestream.
1425 // Note: VM callers should ensure consistency of k/class_name,class_loader
1426 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1428 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1430 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1431 int d_index = dictionary()->hash_to_index(d_hash);
1433 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1434 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1435 int p_index = placeholders()->hash_to_index(p_hash);
1436 PlaceholderEntry* probe;
1438 {
1439 MutexLocker mu(SystemDictionary_lock, THREAD);
1440 // First check if class already defined
1441 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1442 if (check != NULL) {
1443 return(instanceKlassHandle(THREAD, check));
1444 }
1446 // Acquire define token for this class/classloader
1447 symbolHandle nullsymbolHandle;
1448 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1449 // Check if another thread defining in parallel
1450 if (probe->definer() == NULL) {
1451 // Thread will define the class
1452 probe->set_definer(THREAD);
1453 } else {
1454 // Wait for defining thread to finish and return results
1455 while (probe->definer() != NULL) {
1456 SystemDictionary_lock->wait();
1457 }
1458 if (probe->instanceKlass() != NULL) {
1459 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1460 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1461 } else {
1462 // If definer had an error, try again as any new thread would
1463 probe->set_definer(THREAD);
1464 #ifdef ASSERT
1465 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1466 assert(check == NULL, "definer missed recording success");
1467 #endif
1468 }
1469 }
1470 }
1472 define_instance_class(k, THREAD);
1474 Handle linkage_exception = Handle(); // null handle
1476 // definer must notify any waiting threads
1477 {
1478 MutexLocker mu(SystemDictionary_lock, THREAD);
1479 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader);
1480 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1481 if (probe != NULL) {
1482 if (HAS_PENDING_EXCEPTION) {
1483 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1484 CLEAR_PENDING_EXCEPTION;
1485 } else {
1486 probe->set_instanceKlass(k());
1487 }
1488 probe->set_definer(NULL);
1489 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1490 SystemDictionary_lock->notify_all();
1491 }
1492 }
1494 // Can't throw exception while holding lock due to rank ordering
1495 if (linkage_exception() != NULL) {
1496 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1497 }
1499 return k;
1500 }
1502 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1503 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1504 if (class_loader.is_null()) {
1505 return Handle(THREAD, _system_loader_lock_obj);
1506 } else {
1507 return class_loader;
1508 }
1509 }
1511 // This method is added to check how often we have to wait to grab loader
1512 // lock. The results are being recorded in the performance counters defined in
1513 // ClassLoader::_sync_systemLoaderLockContentionRate and
1514 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1515 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1516 if (!UsePerfData) {
1517 return;
1518 }
1520 assert(!loader_lock.is_null(), "NULL lock object");
1522 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1523 == ObjectSynchronizer::owner_other) {
1524 // contention will likely happen, so increment the corresponding
1525 // contention counter.
1526 if (loader_lock() == _system_loader_lock_obj) {
1527 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1528 } else {
1529 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1530 }
1531 }
1532 }
1534 // ----------------------------------------------------------------------------
1535 // Lookup
1537 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1538 symbolHandle class_name,
1539 Handle class_loader) {
1540 assert_locked_or_safepoint(SystemDictionary_lock);
1541 assert (index == dictionary()->index_for(class_name, class_loader),
1542 "incorrect index?");
1544 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1545 return k;
1546 }
1549 // Basic find on classes in the midst of being loaded
1550 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1551 symbolHandle class_name,
1552 Handle class_loader) {
1553 assert_locked_or_safepoint(SystemDictionary_lock);
1555 return placeholders()->find_entry(index, hash, class_name, class_loader);
1556 }
1559 // Used for assertions and verification only
1560 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1561 Handle class_loader) {
1562 #ifndef ASSERT
1563 guarantee(VerifyBeforeGC ||
1564 VerifyDuringGC ||
1565 VerifyBeforeExit ||
1566 VerifyAfterGC, "too expensive");
1567 #endif
1568 assert_locked_or_safepoint(SystemDictionary_lock);
1569 symbolOop class_name_ = class_name();
1570 oop class_loader_ = class_loader();
1572 // First look in the loaded class array
1573 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1574 int d_index = dictionary()->hash_to_index(d_hash);
1575 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1577 if (lookup == NULL) {
1578 // Next try the placeholders
1579 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1580 int p_index = placeholders()->hash_to_index(p_hash);
1581 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1582 }
1584 return lookup;
1585 }
1588 // Get the next class in the diictionary.
1589 klassOop SystemDictionary::try_get_next_class() {
1590 return dictionary()->try_get_next_class();
1591 }
1594 // ----------------------------------------------------------------------------
1595 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1596 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1597 // before a new class is used.
1599 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1600 assert(k.not_null(), "just checking");
1601 // Link into hierachy. Make sure the vtables are initialized before linking into
1602 k->append_to_sibling_list(); // add to superklass/sibling list
1603 k->process_interfaces(THREAD); // handle all "implements" declarations
1604 k->set_init_state(instanceKlass::loaded);
1605 // Now flush all code that depended on old class hierarchy.
1606 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1607 // Also, first reinitialize vtable because it may have gotten out of synch
1608 // while the new class wasn't connected to the class hierarchy.
1609 Universe::flush_dependents_on(k);
1610 }
1613 // ----------------------------------------------------------------------------
1614 // GC support
1616 // Following roots during mark-sweep is separated in two phases.
1617 //
1618 // The first phase follows preloaded classes and all other system
1619 // classes, since these will never get unloaded anyway.
1620 //
1621 // The second phase removes (unloads) unreachable classes from the
1622 // system dictionary and follows the remaining classes' contents.
1624 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1625 // Follow preloaded classes/mirrors and system loader object
1626 blk->do_oop(&_java_system_loader);
1627 preloaded_oops_do(blk);
1628 always_strong_classes_do(blk);
1629 }
1632 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1633 // Follow all system classes and temporary placeholders in dictionary
1634 dictionary()->always_strong_classes_do(blk);
1636 // Placeholders. These are *always* strong roots, as they
1637 // represent classes we're actively loading.
1638 placeholders_do(blk);
1640 // Loader constraints. We must keep the symbolOop used in the name alive.
1641 constraints()->always_strong_classes_do(blk);
1643 // Resolution errors keep the symbolOop for the error alive
1644 resolution_errors()->always_strong_classes_do(blk);
1645 }
1648 void SystemDictionary::placeholders_do(OopClosure* blk) {
1649 placeholders()->oops_do(blk);
1650 }
1653 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1654 bool result = dictionary()->do_unloading(is_alive);
1655 constraints()->purge_loader_constraints(is_alive);
1656 resolution_errors()->purge_resolution_errors(is_alive);
1657 return result;
1658 }
1661 // The mirrors are scanned by shared_oops_do() which is
1662 // not called by oops_do(). In order to process oops in
1663 // a necessary order, shared_oops_do() is call by
1664 // Universe::oops_do().
1665 void SystemDictionary::oops_do(OopClosure* f) {
1666 // Adjust preloaded classes and system loader object
1667 f->do_oop(&_java_system_loader);
1668 preloaded_oops_do(f);
1670 lazily_loaded_oops_do(f);
1672 // Adjust dictionary
1673 dictionary()->oops_do(f);
1675 // Partially loaded classes
1676 placeholders()->oops_do(f);
1678 // Adjust constraint table
1679 constraints()->oops_do(f);
1681 // Adjust resolution error table
1682 resolution_errors()->oops_do(f);
1683 }
1686 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1687 f->do_oop((oop*) &_string_klass);
1688 f->do_oop((oop*) &_object_klass);
1689 f->do_oop((oop*) &_class_klass);
1690 f->do_oop((oop*) &_cloneable_klass);
1691 f->do_oop((oop*) &_classloader_klass);
1692 f->do_oop((oop*) &_serializable_klass);
1693 f->do_oop((oop*) &_system_klass);
1695 f->do_oop((oop*) &_throwable_klass);
1696 f->do_oop((oop*) &_error_klass);
1697 f->do_oop((oop*) &_threaddeath_klass);
1698 f->do_oop((oop*) &_exception_klass);
1699 f->do_oop((oop*) &_runtime_exception_klass);
1700 f->do_oop((oop*) &_classNotFoundException_klass);
1701 f->do_oop((oop*) &_noClassDefFoundError_klass);
1702 f->do_oop((oop*) &_linkageError_klass);
1703 f->do_oop((oop*) &_classCastException_klass);
1704 f->do_oop((oop*) &_arrayStoreException_klass);
1705 f->do_oop((oop*) &_virtualMachineError_klass);
1706 f->do_oop((oop*) &_outOfMemoryError_klass);
1707 f->do_oop((oop*) &_StackOverflowError_klass);
1708 f->do_oop((oop*) &_illegalMonitorStateException_klass);
1709 f->do_oop((oop*) &_protectionDomain_klass);
1710 f->do_oop((oop*) &_AccessControlContext_klass);
1712 f->do_oop((oop*) &_reference_klass);
1713 f->do_oop((oop*) &_soft_reference_klass);
1714 f->do_oop((oop*) &_weak_reference_klass);
1715 f->do_oop((oop*) &_final_reference_klass);
1716 f->do_oop((oop*) &_phantom_reference_klass);
1717 f->do_oop((oop*) &_finalizer_klass);
1719 f->do_oop((oop*) &_thread_klass);
1720 f->do_oop((oop*) &_threadGroup_klass);
1721 f->do_oop((oop*) &_properties_klass);
1722 f->do_oop((oop*) &_reflect_accessible_object_klass);
1723 f->do_oop((oop*) &_reflect_field_klass);
1724 f->do_oop((oop*) &_reflect_method_klass);
1725 f->do_oop((oop*) &_reflect_constructor_klass);
1726 f->do_oop((oop*) &_reflect_magic_klass);
1727 f->do_oop((oop*) &_reflect_method_accessor_klass);
1728 f->do_oop((oop*) &_reflect_constructor_accessor_klass);
1729 f->do_oop((oop*) &_reflect_delegating_classloader_klass);
1730 f->do_oop((oop*) &_reflect_constant_pool_klass);
1731 f->do_oop((oop*) &_reflect_unsafe_static_field_accessor_impl_klass);
1733 f->do_oop((oop*) &_stringBuffer_klass);
1734 f->do_oop((oop*) &_vector_klass);
1735 f->do_oop((oop*) &_hashtable_klass);
1737 f->do_oop((oop*) &_stackTraceElement_klass);
1739 f->do_oop((oop*) &_java_nio_Buffer_klass);
1741 f->do_oop((oop*) &_sun_misc_AtomicLongCSImpl_klass);
1742 f->do_oop((oop*) &_sun_jkernel_DownloadManager_klass);
1744 f->do_oop((oop*) &_boolean_klass);
1745 f->do_oop((oop*) &_char_klass);
1746 f->do_oop((oop*) &_float_klass);
1747 f->do_oop((oop*) &_double_klass);
1748 f->do_oop((oop*) &_byte_klass);
1749 f->do_oop((oop*) &_short_klass);
1750 f->do_oop((oop*) &_int_klass);
1751 f->do_oop((oop*) &_long_klass);
1752 {
1753 for (int i = 0; i < T_VOID+1; i++) {
1754 if (_box_klasses[i] != NULL) {
1755 assert(i >= T_BOOLEAN, "checking");
1756 f->do_oop((oop*) &_box_klasses[i]);
1757 }
1758 }
1759 }
1761 // The basic type mirrors would have already been processed in
1762 // Universe::oops_do(), via a call to shared_oops_do(), so should
1763 // not be processed again.
1765 f->do_oop((oop*) &_system_loader_lock_obj);
1766 FilteredFieldsMap::klasses_oops_do(f);
1767 }
1769 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1770 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1771 }
1773 // Just the classes from defining class loaders
1774 // Don't iterate over placeholders
1775 void SystemDictionary::classes_do(void f(klassOop)) {
1776 dictionary()->classes_do(f);
1777 }
1779 // Added for initialize_itable_for_klass
1780 // Just the classes from defining class loaders
1781 // Don't iterate over placeholders
1782 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1783 dictionary()->classes_do(f, CHECK);
1784 }
1786 // All classes, and their class loaders
1787 // Don't iterate over placeholders
1788 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1789 dictionary()->classes_do(f);
1790 }
1792 // All classes, and their class loaders
1793 // (added for helpers that use HandleMarks and ResourceMarks)
1794 // Don't iterate over placeholders
1795 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1796 dictionary()->classes_do(f, CHECK);
1797 }
1799 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1800 placeholders()->entries_do(f);
1801 }
1803 void SystemDictionary::methods_do(void f(methodOop)) {
1804 dictionary()->methods_do(f);
1805 }
1807 // ----------------------------------------------------------------------------
1808 // Lazily load klasses
1810 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1811 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1813 // if multiple threads calling this function, only one thread will load
1814 // the class. The other threads will find the loaded version once the
1815 // class is loaded.
1816 klassOop aos = _abstract_ownable_synchronizer_klass;
1817 if (aos == NULL) {
1818 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1819 // Force a fence to prevent any read before the write completes
1820 OrderAccess::fence();
1821 _abstract_ownable_synchronizer_klass = k;
1822 }
1823 }
1825 // ----------------------------------------------------------------------------
1826 // Initialization
1828 void SystemDictionary::initialize(TRAPS) {
1829 // Allocate arrays
1830 assert(dictionary() == NULL,
1831 "SystemDictionary should only be initialized once");
1832 _dictionary = new Dictionary(_nof_buckets);
1833 _placeholders = new PlaceholderTable(_nof_buckets);
1834 _number_of_modifications = 0;
1835 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1836 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1838 // Allocate private object used as system class loader lock
1839 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1840 // Initialize basic classes
1841 initialize_preloaded_classes(CHECK);
1842 }
1845 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1846 assert(_object_klass == NULL, "preloaded classes should only be initialized once");
1847 // Preload commonly used klasses
1848 _object_klass = resolve_or_fail(vmSymbolHandles::java_lang_Object(), true, CHECK);
1849 _string_klass = resolve_or_fail(vmSymbolHandles::java_lang_String(), true, CHECK);
1850 _class_klass = resolve_or_fail(vmSymbolHandles::java_lang_Class(), true, CHECK);
1851 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(_class_klass));
1852 // Fixup mirrors for classes loaded before java.lang.Class.
1853 // These calls iterate over the objects currently in the perm gen
1854 // so calling them at this point is matters (not before when there
1855 // are fewer objects and not later after there are more objects
1856 // in the perm gen.
1857 Universe::initialize_basic_type_mirrors(CHECK);
1858 Universe::fixup_mirrors(CHECK);
1860 _cloneable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Cloneable(), true, CHECK);
1861 _classloader_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassLoader(), true, CHECK);
1862 _serializable_klass = resolve_or_fail(vmSymbolHandles::java_io_Serializable(), true, CHECK);
1863 _system_klass = resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
1865 _throwable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Throwable(), true, CHECK);
1866 _error_klass = resolve_or_fail(vmSymbolHandles::java_lang_Error(), true, CHECK);
1867 _threaddeath_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadDeath(), true, CHECK);
1868 _exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_Exception(), true, CHECK);
1869 _runtime_exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_RuntimeException(), true, CHECK);
1870 _protectionDomain_klass = resolve_or_fail(vmSymbolHandles::java_security_ProtectionDomain(), true, CHECK);
1871 _AccessControlContext_klass = resolve_or_fail(vmSymbolHandles::java_security_AccessControlContext(), true, CHECK);
1872 _classNotFoundException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassNotFoundException(), true, CHECK);
1873 _noClassDefFoundError_klass = resolve_or_fail(vmSymbolHandles::java_lang_NoClassDefFoundError(), true, CHECK);
1874 _linkageError_klass = resolve_or_fail(vmSymbolHandles::java_lang_LinkageError(), true, CHECK);
1875 _classCastException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassCastException(), true, CHECK);
1876 _arrayStoreException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ArrayStoreException(), true, CHECK);
1877 _virtualMachineError_klass = resolve_or_fail(vmSymbolHandles::java_lang_VirtualMachineError(), true, CHECK);
1878 _outOfMemoryError_klass = resolve_or_fail(vmSymbolHandles::java_lang_OutOfMemoryError(), true, CHECK);
1879 _StackOverflowError_klass = resolve_or_fail(vmSymbolHandles::java_lang_StackOverflowError(), true, CHECK);
1880 _illegalMonitorStateException_klass = resolve_or_fail(vmSymbolHandles::java_lang_IllegalMonitorStateException(), true, CHECK);
1882 // Preload ref klasses and set reference types
1883 _reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Reference(), true, CHECK);
1884 instanceKlass::cast(_reference_klass)->set_reference_type(REF_OTHER);
1885 instanceRefKlass::update_nonstatic_oop_maps(_reference_klass);
1887 _soft_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_SoftReference(), true, CHECK);
1888 instanceKlass::cast(_soft_reference_klass)->set_reference_type(REF_SOFT);
1889 _weak_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_WeakReference(), true, CHECK);
1890 instanceKlass::cast(_weak_reference_klass)->set_reference_type(REF_WEAK);
1891 _final_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_FinalReference(), true, CHECK);
1892 instanceKlass::cast(_final_reference_klass)->set_reference_type(REF_FINAL);
1893 _phantom_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_PhantomReference(), true, CHECK);
1894 instanceKlass::cast(_phantom_reference_klass)->set_reference_type(REF_PHANTOM);
1895 _finalizer_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Finalizer(), true, CHECK);
1897 _thread_klass = resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
1898 _threadGroup_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK);
1899 _properties_klass = resolve_or_fail(vmSymbolHandles::java_util_Properties(), true, CHECK);
1900 _reflect_accessible_object_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_AccessibleObject(), true, CHECK);
1901 _reflect_field_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Field(), true, CHECK);
1902 _reflect_method_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Method(), true, CHECK);
1903 _reflect_constructor_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Constructor(), true, CHECK);
1904 // Universe::is_gte_jdk14x_version() is not set up by this point.
1905 // It's okay if these turn out to be NULL in non-1.4 JDKs.
1906 _reflect_magic_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MagicAccessorImpl(), CHECK);
1907 _reflect_method_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MethodAccessorImpl(), CHECK);
1908 _reflect_constructor_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstructorAccessorImpl(), CHECK);
1909 _reflect_delegating_classloader_klass = resolve_or_null(vmSymbolHandles::sun_reflect_DelegatingClassLoader(), CHECK);
1910 _reflect_constant_pool_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstantPool(), CHECK);
1911 _reflect_unsafe_static_field_accessor_impl_klass = resolve_or_null(vmSymbolHandles::sun_reflect_UnsafeStaticFieldAccessorImpl(), CHECK);
1913 _vector_klass = resolve_or_fail(vmSymbolHandles::java_util_Vector(), true, CHECK);
1914 _hashtable_klass = resolve_or_fail(vmSymbolHandles::java_util_Hashtable(), true, CHECK);
1915 _stringBuffer_klass = resolve_or_fail(vmSymbolHandles::java_lang_StringBuffer(), true, CHECK);
1917 // It's NULL in non-1.4 JDKs.
1918 _stackTraceElement_klass = resolve_or_null(vmSymbolHandles::java_lang_StackTraceElement(), CHECK);
1920 // Universe::is_gte_jdk14x_version() is not set up by this point.
1921 // It's okay if this turns out to be NULL in non-1.4 JDKs.
1922 _java_nio_Buffer_klass = resolve_or_null(vmSymbolHandles::java_nio_Buffer(), CHECK);
1924 // If this class isn't present, it won't be referenced.
1925 _sun_misc_AtomicLongCSImpl_klass = resolve_or_null(vmSymbolHandles::sun_misc_AtomicLongCSImpl(), CHECK);
1926 #ifdef KERNEL
1927 _sun_jkernel_DownloadManager_klass = resolve_or_null(vmSymbolHandles::sun_jkernel_DownloadManager(), CHECK);
1928 if (_sun_jkernel_DownloadManager_klass == NULL) {
1929 warning("Cannot find sun/jkernel/DownloadManager");
1930 }
1931 #endif // KERNEL
1933 // Preload boxing klasses
1934 _boolean_klass = resolve_or_fail(vmSymbolHandles::java_lang_Boolean(), true, CHECK);
1935 _char_klass = resolve_or_fail(vmSymbolHandles::java_lang_Character(), true, CHECK);
1936 _float_klass = resolve_or_fail(vmSymbolHandles::java_lang_Float(), true, CHECK);
1937 _double_klass = resolve_or_fail(vmSymbolHandles::java_lang_Double(), true, CHECK);
1938 _byte_klass = resolve_or_fail(vmSymbolHandles::java_lang_Byte(), true, CHECK);
1939 _short_klass = resolve_or_fail(vmSymbolHandles::java_lang_Short(), true, CHECK);
1940 _int_klass = resolve_or_fail(vmSymbolHandles::java_lang_Integer(), true, CHECK);
1941 _long_klass = resolve_or_fail(vmSymbolHandles::java_lang_Long(), true, CHECK);
1943 _box_klasses[T_BOOLEAN] = _boolean_klass;
1944 _box_klasses[T_CHAR] = _char_klass;
1945 _box_klasses[T_FLOAT] = _float_klass;
1946 _box_klasses[T_DOUBLE] = _double_klass;
1947 _box_klasses[T_BYTE] = _byte_klass;
1948 _box_klasses[T_SHORT] = _short_klass;
1949 _box_klasses[T_INT] = _int_klass;
1950 _box_klasses[T_LONG] = _long_klass;
1951 //_box_klasses[T_OBJECT] = _object_klass;
1952 //_box_klasses[T_ARRAY] = _object_klass;
1954 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1955 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1956 _has_loadClassInternal = (method != NULL);
1957 }
1959 { // Compute whether we should use checkPackageAccess or NOT
1960 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1961 _has_checkPackageAccess = (method != NULL);
1962 }
1963 }
1965 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1966 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1967 BasicType SystemDictionary::box_klass_type(klassOop k) {
1968 assert(k != NULL, "");
1969 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1970 if (_box_klasses[i] == k)
1971 return (BasicType)i;
1972 }
1973 return T_OBJECT;
1974 }
1976 // Constraints on class loaders. The details of the algorithm can be
1977 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1978 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1979 // that the system dictionary needs to maintain a set of contraints that
1980 // must be satisfied by all classes in the dictionary.
1981 // if defining is true, then LinkageError if already in systemDictionary
1982 // if initiating loader, then ok if instanceKlass matches existing entry
1984 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1985 instanceKlassHandle k,
1986 Handle class_loader, bool defining,
1987 TRAPS) {
1988 const char *linkage_error = NULL;
1989 {
1990 symbolHandle name (THREAD, k->name());
1991 MutexLocker mu(SystemDictionary_lock, THREAD);
1993 klassOop check = find_class(d_index, d_hash, name, class_loader);
1994 if (check != (klassOop)NULL) {
1995 // if different instanceKlass - duplicate class definition,
1996 // else - ok, class loaded by a different thread in parallel,
1997 // we should only have found it if it was done loading and ok to use
1998 // system dictionary only holds instance classes, placeholders
1999 // also holds array classes
2001 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2002 if ((defining == true) || (k() != check)) {
2003 linkage_error = "loader (instance of %s): attempted duplicate class "
2004 "definition for name: \"%s\"";
2005 } else {
2006 return;
2007 }
2008 }
2010 #ifdef ASSERT
2011 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
2012 int p_index = placeholders()->hash_to_index(p_hash);
2013 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2014 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
2015 #endif
2017 if (linkage_error == NULL) {
2018 if (constraints()->check_or_update(k, class_loader, name) == false) {
2019 linkage_error = "loader constraint violation: loader (instance of %s)"
2020 " previously initiated loading for a different type with name \"%s\"";
2021 }
2022 }
2023 }
2025 // Throw error now if needed (cannot throw while holding
2026 // SystemDictionary_lock because of rank ordering)
2028 if (linkage_error) {
2029 ResourceMark rm(THREAD);
2030 const char* class_loader_name = loader_name(class_loader());
2031 char* type_name = k->name()->as_C_string();
2032 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2033 strlen(type_name);
2034 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2035 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2036 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2037 }
2038 }
2041 // Update system dictionary - done after check_constraint and add_to_hierachy
2042 // have been called.
2043 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2044 int p_index, unsigned int p_hash,
2045 instanceKlassHandle k,
2046 Handle class_loader,
2047 TRAPS) {
2048 // Compile_lock prevents systemDictionary updates during compilations
2049 assert_locked_or_safepoint(Compile_lock);
2050 symbolHandle name (THREAD, k->name());
2052 {
2053 MutexLocker mu1(SystemDictionary_lock, THREAD);
2055 // See whether biased locking is enabled and if so set it for this
2056 // klass.
2057 // Note that this must be done past the last potential blocking
2058 // point / safepoint. We enable biased locking lazily using a
2059 // VM_Operation to iterate the SystemDictionary and installing the
2060 // biasable mark word into each instanceKlass's prototype header.
2061 // To avoid race conditions where we accidentally miss enabling the
2062 // optimization for one class in the process of being added to the
2063 // dictionary, we must not safepoint after the test of
2064 // BiasedLocking::enabled().
2065 if (UseBiasedLocking && BiasedLocking::enabled()) {
2066 // Set biased locking bit for all loaded classes; it will be
2067 // cleared if revocation occurs too often for this type
2068 // NOTE that we must only do this when the class is initally
2069 // defined, not each time it is referenced from a new class loader
2070 if (k->class_loader() == class_loader()) {
2071 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2072 }
2073 }
2075 // Check for a placeholder. If there, remove it and make a
2076 // new system dictionary entry.
2077 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2078 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2079 if (sd_check == NULL) {
2080 dictionary()->add_klass(name, class_loader, k);
2081 notice_modification();
2082 }
2083 #ifdef ASSERT
2084 sd_check = find_class(d_index, d_hash, name, class_loader);
2085 assert (sd_check != NULL, "should have entry in system dictionary");
2086 // Changed to allow PH to remain to complete class circularity checking
2087 // while only one thread can define a class at one time, multiple
2088 // classes can resolve the superclass for a class at one time,
2089 // and the placeholder is used to track that
2090 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2091 // assert (ph_check == NULL, "should not have a placeholder entry");
2092 #endif
2093 SystemDictionary_lock->notify_all();
2094 }
2095 }
2098 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2099 symbolHandle class_name, Handle class_loader, TRAPS) {
2101 // First see if it has been loaded directly.
2102 // Force the protection domain to be null. (This removes protection checks.)
2103 Handle no_protection_domain;
2104 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2105 no_protection_domain, CHECK_NULL);
2106 if (klass != NULL)
2107 return klass;
2109 // Now look to see if it has been loaded elsewhere, and is subject to
2110 // a loader constraint that would require this loader to return the
2111 // klass that is already loaded.
2112 if (FieldType::is_array(class_name())) {
2113 // Array classes are hard because their klassOops are not kept in the
2114 // constraint table. The array klass may be constrained, but the elem class
2115 // may not be.
2116 jint dimension;
2117 symbolOop object_key;
2118 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2119 &object_key, CHECK_(NULL));
2120 if (t != T_OBJECT) {
2121 klass = Universe::typeArrayKlassObj(t);
2122 } else {
2123 symbolHandle elem_name(THREAD, object_key);
2124 MutexLocker mu(SystemDictionary_lock, THREAD);
2125 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2126 }
2127 if (klass != NULL) {
2128 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2129 }
2130 } else {
2131 MutexLocker mu(SystemDictionary_lock, THREAD);
2132 // Non-array classes are easy: simply check the constraint table.
2133 klass = constraints()->find_constrained_klass(class_name, class_loader);
2134 }
2136 return klass;
2137 }
2140 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2141 Handle class_loader1,
2142 Handle class_loader2,
2143 Thread* THREAD) {
2144 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2145 int d_index1 = dictionary()->hash_to_index(d_hash1);
2147 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2148 int d_index2 = dictionary()->hash_to_index(d_hash2);
2150 {
2151 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2153 // Better never do a GC while we're holding these oops
2154 No_Safepoint_Verifier nosafepoint;
2156 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2157 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2158 return constraints()->add_entry(class_name, klass1, class_loader1,
2159 klass2, class_loader2);
2160 }
2161 }
2163 // Add entry to resolution error table to record the error when the first
2164 // attempt to resolve a reference to a class has failed.
2165 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2166 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2167 int index = resolution_errors()->hash_to_index(hash);
2168 {
2169 MutexLocker ml(SystemDictionary_lock, Thread::current());
2170 resolution_errors()->add_entry(index, hash, pool, which, error);
2171 }
2172 }
2174 // Lookup resolution error table. Returns error if found, otherwise NULL.
2175 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2176 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2177 int index = resolution_errors()->hash_to_index(hash);
2178 {
2179 MutexLocker ml(SystemDictionary_lock, Thread::current());
2180 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2181 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2182 }
2183 }
2186 // Make sure all class components (including arrays) in the given
2187 // signature will be resolved to the same class in both loaders.
2188 // Returns the name of the type that failed a loader constraint check, or
2189 // NULL if no constraint failed. The returned C string needs cleaning up
2190 // with a ResourceMark in the caller
2191 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2192 Handle loader1, Handle loader2,
2193 bool is_method, TRAPS) {
2194 // Nothing to do if loaders are the same.
2195 if (loader1() == loader2()) {
2196 return NULL;
2197 }
2199 SignatureStream sig_strm(signature, is_method);
2200 while (!sig_strm.is_done()) {
2201 if (sig_strm.is_object()) {
2202 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2203 symbolHandle sig (THREAD, s);
2204 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2205 return sig()->as_C_string();
2206 }
2207 }
2208 sig_strm.next();
2209 }
2210 return NULL;
2211 }
2214 // Since the identity hash code for symbols changes when the symbols are
2215 // moved from the regular perm gen (hash in the mark word) to the shared
2216 // spaces (hash is the address), the classes loaded into the dictionary
2217 // may be in the wrong buckets.
2219 void SystemDictionary::reorder_dictionary() {
2220 dictionary()->reorder_dictionary();
2221 }
2224 void SystemDictionary::copy_buckets(char** top, char* end) {
2225 dictionary()->copy_buckets(top, end);
2226 }
2229 void SystemDictionary::copy_table(char** top, char* end) {
2230 dictionary()->copy_table(top, end);
2231 }
2234 void SystemDictionary::reverse() {
2235 dictionary()->reverse();
2236 }
2238 int SystemDictionary::number_of_classes() {
2239 return dictionary()->number_of_entries();
2240 }
2243 // ----------------------------------------------------------------------------
2244 #ifndef PRODUCT
2246 void SystemDictionary::print() {
2247 dictionary()->print();
2249 // Placeholders
2250 GCMutexLocker mu(SystemDictionary_lock);
2251 placeholders()->print();
2253 // loader constraints - print under SD_lock
2254 constraints()->print();
2255 }
2257 #endif
2259 void SystemDictionary::verify() {
2260 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2261 guarantee(constraints() != NULL,
2262 "Verify of loader constraints failed");
2263 guarantee(dictionary()->number_of_entries() >= 0 &&
2264 placeholders()->number_of_entries() >= 0,
2265 "Verify of system dictionary failed");
2267 // Verify dictionary
2268 dictionary()->verify();
2270 GCMutexLocker mu(SystemDictionary_lock);
2271 placeholders()->verify();
2273 // Verify constraint table
2274 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2275 constraints()->verify(dictionary());
2276 }
2279 void SystemDictionary::verify_obj_klass_present(Handle obj,
2280 symbolHandle class_name,
2281 Handle class_loader) {
2282 GCMutexLocker mu(SystemDictionary_lock);
2283 oop probe = find_class_or_placeholder(class_name, class_loader);
2284 if (probe == NULL) {
2285 probe = SystemDictionary::find_shared_class(class_name);
2286 }
2287 guarantee(probe != NULL &&
2288 (!probe->is_klass() || probe == obj()),
2289 "Loaded klasses should be in SystemDictionary");
2290 }
2292 #ifndef PRODUCT
2294 // statistics code
2295 class ClassStatistics: AllStatic {
2296 private:
2297 static int nclasses; // number of classes
2298 static int nmethods; // number of methods
2299 static int nmethoddata; // number of methodData
2300 static int class_size; // size of class objects in words
2301 static int method_size; // size of method objects in words
2302 static int debug_size; // size of debug info in methods
2303 static int methoddata_size; // size of methodData objects in words
2305 static void do_class(klassOop k) {
2306 nclasses++;
2307 class_size += k->size();
2308 if (k->klass_part()->oop_is_instance()) {
2309 instanceKlass* ik = (instanceKlass*)k->klass_part();
2310 class_size += ik->methods()->size();
2311 class_size += ik->constants()->size();
2312 class_size += ik->local_interfaces()->size();
2313 class_size += ik->transitive_interfaces()->size();
2314 // We do not have to count implementors, since we only store one!
2315 class_size += ik->fields()->size();
2316 }
2317 }
2319 static void do_method(methodOop m) {
2320 nmethods++;
2321 method_size += m->size();
2322 // class loader uses same objArray for empty vectors, so don't count these
2323 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2324 if (m->has_stackmap_table()) {
2325 method_size += m->stackmap_data()->size();
2326 }
2328 methodDataOop mdo = m->method_data();
2329 if (mdo != NULL) {
2330 nmethoddata++;
2331 methoddata_size += mdo->size();
2332 }
2333 }
2335 public:
2336 static void print() {
2337 SystemDictionary::classes_do(do_class);
2338 SystemDictionary::methods_do(do_method);
2339 tty->print_cr("Class statistics:");
2340 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2341 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2342 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2343 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2344 }
2345 };
2348 int ClassStatistics::nclasses = 0;
2349 int ClassStatistics::nmethods = 0;
2350 int ClassStatistics::nmethoddata = 0;
2351 int ClassStatistics::class_size = 0;
2352 int ClassStatistics::method_size = 0;
2353 int ClassStatistics::debug_size = 0;
2354 int ClassStatistics::methoddata_size = 0;
2356 void SystemDictionary::print_class_statistics() {
2357 ResourceMark rm;
2358 ClassStatistics::print();
2359 }
2362 class MethodStatistics: AllStatic {
2363 public:
2364 enum {
2365 max_parameter_size = 10
2366 };
2367 private:
2369 static int _number_of_methods;
2370 static int _number_of_final_methods;
2371 static int _number_of_static_methods;
2372 static int _number_of_native_methods;
2373 static int _number_of_synchronized_methods;
2374 static int _number_of_profiled_methods;
2375 static int _number_of_bytecodes;
2376 static int _parameter_size_profile[max_parameter_size];
2377 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2379 static void initialize() {
2380 _number_of_methods = 0;
2381 _number_of_final_methods = 0;
2382 _number_of_static_methods = 0;
2383 _number_of_native_methods = 0;
2384 _number_of_synchronized_methods = 0;
2385 _number_of_profiled_methods = 0;
2386 _number_of_bytecodes = 0;
2387 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2388 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2389 };
2391 static void do_method(methodOop m) {
2392 _number_of_methods++;
2393 // collect flag info
2394 if (m->is_final() ) _number_of_final_methods++;
2395 if (m->is_static() ) _number_of_static_methods++;
2396 if (m->is_native() ) _number_of_native_methods++;
2397 if (m->is_synchronized()) _number_of_synchronized_methods++;
2398 if (m->method_data() != NULL) _number_of_profiled_methods++;
2399 // collect parameter size info (add one for receiver, if any)
2400 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2401 // collect bytecodes info
2402 {
2403 Thread *thread = Thread::current();
2404 HandleMark hm(thread);
2405 BytecodeStream s(methodHandle(thread, m));
2406 Bytecodes::Code c;
2407 while ((c = s.next()) >= 0) {
2408 _number_of_bytecodes++;
2409 _bytecodes_profile[c]++;
2410 }
2411 }
2412 }
2414 public:
2415 static void print() {
2416 initialize();
2417 SystemDictionary::methods_do(do_method);
2418 // generate output
2419 tty->cr();
2420 tty->print_cr("Method statistics (static):");
2421 // flag distribution
2422 tty->cr();
2423 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2424 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2425 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2426 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2427 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2428 // parameter size profile
2429 tty->cr();
2430 { int tot = 0;
2431 int avg = 0;
2432 for (int i = 0; i < max_parameter_size; i++) {
2433 int n = _parameter_size_profile[i];
2434 tot += n;
2435 avg += n*i;
2436 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2437 }
2438 assert(tot == _number_of_methods, "should be the same");
2439 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2440 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2441 }
2442 // bytecodes profile
2443 tty->cr();
2444 { int tot = 0;
2445 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2446 if (Bytecodes::is_defined(i)) {
2447 Bytecodes::Code c = Bytecodes::cast(i);
2448 int n = _bytecodes_profile[c];
2449 tot += n;
2450 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2451 }
2452 }
2453 assert(tot == _number_of_bytecodes, "should be the same");
2454 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2455 }
2456 tty->cr();
2457 }
2458 };
2460 int MethodStatistics::_number_of_methods;
2461 int MethodStatistics::_number_of_final_methods;
2462 int MethodStatistics::_number_of_static_methods;
2463 int MethodStatistics::_number_of_native_methods;
2464 int MethodStatistics::_number_of_synchronized_methods;
2465 int MethodStatistics::_number_of_profiled_methods;
2466 int MethodStatistics::_number_of_bytecodes;
2467 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2468 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2471 void SystemDictionary::print_method_statistics() {
2472 MethodStatistics::print();
2473 }
2475 #endif // PRODUCT