1 #ifdef USE_PRAGMA_IDENT_SRC
2 #pragma ident "@(#)systemDictionary.cpp 1.367 08/01/17 09:41:11 JVM"
3 #endif
4 /*
5 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 # include "incls/_precompiled.incl"
29 # include "incls/_systemDictionary.cpp.incl"
30
31
32 Dictionary* SystemDictionary::_dictionary = NULL;
33 PlaceholderTable* SystemDictionary::_placeholders = NULL;
34 Dictionary* SystemDictionary::_shared_dictionary = NULL;
35 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
36 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
37
38
39 int SystemDictionary::_number_of_modifications = 0;
40
41 oop SystemDictionary::_system_loader_lock_obj = NULL;
42
43 klassOop SystemDictionary::_object_klass = NULL;
44 klassOop SystemDictionary::_string_klass = NULL;
45 klassOop SystemDictionary::_class_klass = NULL;
46 klassOop SystemDictionary::_cloneable_klass = NULL;
47 klassOop SystemDictionary::_classloader_klass = NULL;
48 klassOop SystemDictionary::_serializable_klass = NULL;
49 klassOop SystemDictionary::_system_klass = NULL;
50
51 klassOop SystemDictionary::_throwable_klass = NULL;
52 klassOop SystemDictionary::_error_klass = NULL;
53 klassOop SystemDictionary::_threaddeath_klass = NULL;
54 klassOop SystemDictionary::_exception_klass = NULL;
55 klassOop SystemDictionary::_runtime_exception_klass = NULL;
56 klassOop SystemDictionary::_classNotFoundException_klass = NULL;
57 klassOop SystemDictionary::_noClassDefFoundError_klass = NULL;
58 klassOop SystemDictionary::_linkageError_klass = NULL;
59 klassOop SystemDictionary::_classCastException_klass = NULL;
60 klassOop SystemDictionary::_arrayStoreException_klass = NULL;
61 klassOop SystemDictionary::_virtualMachineError_klass = NULL;
62 klassOop SystemDictionary::_outOfMemoryError_klass = NULL;
63 klassOop SystemDictionary::_StackOverflowError_klass = NULL;
64 klassOop SystemDictionary::_illegalMonitorStateException_klass = NULL;
65 klassOop SystemDictionary::_protectionDomain_klass = NULL;
66 klassOop SystemDictionary::_AccessControlContext_klass = NULL;
67
68 klassOop SystemDictionary::_reference_klass = NULL;
69 klassOop SystemDictionary::_soft_reference_klass = NULL;
70 klassOop SystemDictionary::_weak_reference_klass = NULL;
71 klassOop SystemDictionary::_final_reference_klass = NULL;
72 klassOop SystemDictionary::_phantom_reference_klass = NULL;
73 klassOop SystemDictionary::_finalizer_klass = NULL;
74
75 klassOop SystemDictionary::_thread_klass = NULL;
76 klassOop SystemDictionary::_threadGroup_klass = NULL;
77 klassOop SystemDictionary::_properties_klass = NULL;
78 klassOop SystemDictionary::_reflect_accessible_object_klass = NULL;
79 klassOop SystemDictionary::_reflect_field_klass = NULL;
80 klassOop SystemDictionary::_reflect_method_klass = NULL;
81 klassOop SystemDictionary::_reflect_constructor_klass = NULL;
82 klassOop SystemDictionary::_reflect_magic_klass = NULL;
83 klassOop SystemDictionary::_reflect_method_accessor_klass = NULL;
84 klassOop SystemDictionary::_reflect_constructor_accessor_klass = NULL;
85 klassOop SystemDictionary::_reflect_delegating_classloader_klass = NULL;
86 klassOop SystemDictionary::_reflect_constant_pool_klass = NULL;
87 klassOop SystemDictionary::_reflect_unsafe_static_field_accessor_impl_klass = NULL;
88
89 klassOop SystemDictionary::_vector_klass = NULL;
90 klassOop SystemDictionary::_hashtable_klass = NULL;
91 klassOop SystemDictionary::_stringBuffer_klass = NULL;
92
93 klassOop SystemDictionary::_stackTraceElement_klass = NULL;
94
95 klassOop SystemDictionary::_java_nio_Buffer_klass = NULL;
96
97 klassOop SystemDictionary::_sun_misc_AtomicLongCSImpl_klass = NULL;
98 klassOop SystemDictionary::_sun_jkernel_DownloadManager_klass = NULL;
99
100 klassOop SystemDictionary::_boolean_klass = NULL;
101 klassOop SystemDictionary::_char_klass = NULL;
102 klassOop SystemDictionary::_float_klass = NULL;
103 klassOop SystemDictionary::_double_klass = NULL;
104 klassOop SystemDictionary::_byte_klass = NULL;
105 klassOop SystemDictionary::_short_klass = NULL;
106 klassOop SystemDictionary::_int_klass = NULL;
107 klassOop SystemDictionary::_long_klass = NULL;
108 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
109
110 oop SystemDictionary::_java_system_loader = NULL;
111
112 bool SystemDictionary::_has_loadClassInternal = false;
113 bool SystemDictionary::_has_checkPackageAccess = false;
114
115 // lazily initialized klass variables
116 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
117
118
119 // ----------------------------------------------------------------------------
120 // Java-level SystemLoader
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader;
124 }
125
126 void SystemDictionary::compute_java_system_loader(TRAPS) {
127 KlassHandle system_klass(THREAD, _classloader_klass);
128 JavaValue result(T_OBJECT);
129 JavaCalls::call_static(&result,
130 KlassHandle(THREAD, _classloader_klass),
131 vmSymbolHandles::getSystemClassLoader_name(),
132 vmSymbolHandles::void_classloader_signature(),
133 CHECK);
134
135 _java_system_loader = (oop)result.get_jobject();
136 }
137
138
139 // ----------------------------------------------------------------------------
140 // debugging
141
142 #ifdef ASSERT
143
144 // return true if class_name contains no '.' (internal format is '/')
145 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
146 if (class_name.not_null()) {
147 ResourceMark rm;
148 char* name = class_name->as_C_string();
149 return strchr(name, '.') == NULL;
150 } else {
151 return true;
152 }
153 }
154
155 #endif
156
157 // ----------------------------------------------------------------------------
158 // Resolving of classes
159
160 // Forwards to resolve_or_null
161
162 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
163 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
164 if (HAS_PENDING_EXCEPTION || klass == NULL) {
165 KlassHandle k_h(THREAD, klass);
166 // can return a null klass
167 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
168 }
169 return klass;
170 }
171
172 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
173 if (HAS_PENDING_EXCEPTION) {
174 // If we have a pending exception we forward it to the caller, unless throw_error is true,
175 // in which case we have to check whether the pending exception is a ClassNotFoundException,
176 // and if so convert it to a NoClassDefFoundError
177 // And chain the original ClassNotFoundException
178 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
179 ResourceMark rm(THREAD);
180 assert(klass_h() == NULL, "Should not have result with exception pending");
181 Handle e(THREAD, PENDING_EXCEPTION);
182 CLEAR_PENDING_EXCEPTION;
183 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
184 } else {
185 return NULL;
186 }
187 }
188 // Class not found, throw appropriate error or exception depending on value of throw_error
189 if (klass_h() == NULL) {
190 ResourceMark rm(THREAD);
191 if (throw_error) {
192 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
193 } else {
194 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
195 }
196 }
197 return (klassOop)klass_h();
198 }
199
200
201 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
202 bool throw_error, TRAPS)
203 {
204 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
205 }
206
207
208 // Forwards to resolve_instance_class_or_null
209
210 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
211 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
212 if (FieldType::is_array(class_name())) {
213 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
214 } else {
215 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
216 }
217 }
218
219 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
220 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
221 }
222
223 // Forwards to resolve_instance_class_or_null
224
225 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
226 Handle class_loader,
227 Handle protection_domain,
228 TRAPS) {
229 assert(FieldType::is_array(class_name()), "must be array");
230 jint dimension;
231 symbolOop object_key;
232 klassOop k = NULL;
233 // dimension and object_key are assigned as a side-effect of this call
234 BasicType t = FieldType::get_array_info(class_name(),
235 &dimension,
236 &object_key,
237 CHECK_NULL);
238
239 if (t == T_OBJECT) {
240 symbolHandle h_key(THREAD, object_key);
241 // naked oop "k" is OK here -- we assign back into it
242 k = SystemDictionary::resolve_instance_class_or_null(h_key,
243 class_loader,
244 protection_domain,
245 CHECK_NULL);
246 if (k != NULL) {
247 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
248 }
249 } else {
250 k = Universe::typeArrayKlassObj(t);
251 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
252 }
253 return k;
254 }
255
256
257 // Must be called for any super-class or super-interface resolution
258 // during class definition to allow class circularity checking
259 // super-interface callers:
260 // parse_interfaces - for defineClass & jvmtiRedefineClasses
261 // super-class callers:
262 // ClassFileParser - for defineClass & jvmtiRedefineClasses
263 // load_shared_class - while loading a class from shared archive
264 // resolve_instance_class_or_fail:
265 // when resolving a class that has an existing placeholder with
266 // a saved superclass [i.e. a defineClass is currently in progress]
267 // if another thread is trying to resolve the class, it must do
268 // super-class checks on its own thread to catch class circularity
269 // This last call is critical in class circularity checking for cases
270 // where classloading is delegated to different threads and the
271 // classloader lock is released.
272 // Take the case: Base->Super->Base
273 // 1. If thread T1 tries to do a defineClass of class Base
274 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
275 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
276 // so it tries to load Super
277 // 3. If we load the class internally, or user classloader uses same thread
278 // loadClassFromxxx or defineClass via parseClassFile Super ...
279 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
280 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
281 // 3.4 calls resolve_super_or_fail Base
282 // 3.5 finds T1,Base -> throws class circularity
283 //OR 4. If T2 tries to resolve Super via defineClass Super ...
284 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
285 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
286 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
287 // 4.4 finds T2, Super -> throws class circularity
288 // Must be called, even if superclass is null, since this is
289 // where the placeholder entry is created which claims this
290 // thread is loading this class/classloader.
291 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
292 symbolHandle class_name,
293 Handle class_loader,
294 Handle protection_domain,
295 bool is_superclass,
296 TRAPS) {
297
298 // Double-check, if child class is already loaded, just return super-class,interface
299 // Don't add a placedholder if already loaded, i.e. already in system dictionary
300 // Make sure there's a placeholder for the *child* before resolving.
301 // Used as a claim that this thread is currently loading superclass/classloader
302 // Used here for ClassCircularity checks and also for heap verification
303 // (every instanceKlass in the heap needs to be in the system dictionary
304 // or have a placeholder).
305 // Must check ClassCircularity before checking if super class is already loaded
306 //
307 // We might not already have a placeholder if this child_name was
308 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
309 // the name of the class might not be known until the stream is actually
310 // parsed.
311 // Bugs 4643874, 4715493
312 // compute_hash can have a safepoint
313
314 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
315 int d_index = dictionary()->hash_to_index(d_hash);
316 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
317 int p_index = placeholders()->hash_to_index(p_hash);
318 // can't throw error holding a lock
319 bool child_already_loaded = false;
320 bool throw_circularity_error = false;
321 {
322 MutexLocker mu(SystemDictionary_lock, THREAD);
323 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
324 klassOop quicksuperk;
325 // to support // loading: if child done loading, just return superclass
326 // if class_name, & class_loader don't match:
327 // if initial define, SD update will give LinkageError
328 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
329 // so we don't throw an exception here.
330 // see: nsk redefclass014 & java.lang.instrument Instrument032
331 if ((childk != NULL ) && (is_superclass) &&
332 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
333
334 ((Klass::cast(quicksuperk)->name() == class_name()) &&
335 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
336 return quicksuperk;
337 } else {
338 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
339 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
340 throw_circularity_error = true;
341 }
342
343 // add placeholder entry even if error - callers will remove on error
344 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
345 if (throw_circularity_error) {
346 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
347 }
348 }
349 }
350 if (throw_circularity_error) {
351 ResourceMark rm(THREAD);
352 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
353 }
354
355 // java.lang.Object should have been found above
356 assert(class_name() != NULL, "null super class for resolving");
357 // Resolve the super class or interface, check results on return
358 klassOop superk = NULL;
359 superk = SystemDictionary::resolve_or_null(class_name,
360 class_loader,
361 protection_domain,
362 THREAD);
363
364 KlassHandle superk_h(THREAD, superk);
365
366 // Note: clean up of placeholders currently in callers of
367 // resolve_super_or_fail - either at update_dictionary time
368 // or on error
369 {
370 MutexLocker mu(SystemDictionary_lock, THREAD);
371 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
372 if (probe != NULL) {
373 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
374 }
375 }
376 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
377 // can null superk
378 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
379 }
380
381 return superk_h();
382 }
383
384
385 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
386 Handle class_loader,
387 Handle protection_domain,
388 TRAPS) {
389 if(!has_checkPackageAccess()) return;
390
391 // Now we have to call back to java to check if the initating class has access
392 JavaValue result(T_VOID);
393 if (TraceProtectionDomainVerification) {
394 // Print out trace information
395 tty->print_cr("Checking package access");
396 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
397 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
398 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
399 }
400
401 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
402
403 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
404 JavaCalls::call_special(&result,
405 class_loader,
406 system_loader,
407 vmSymbolHandles::checkPackageAccess_name(),
408 vmSymbolHandles::class_protectiondomain_signature(),
409 Handle(THREAD, klass->java_mirror()),
410 protection_domain,
411 THREAD);
412
413 if (TraceProtectionDomainVerification) {
414 if (HAS_PENDING_EXCEPTION) {
415 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
416 } else {
417 tty->print_cr(" -> granted");
418 }
419 tty->cr();
420 }
421
422 if (HAS_PENDING_EXCEPTION) return;
423
424 // If no exception has been thrown, we have validated the protection domain
425 // Insert the protection domain of the initiating class into the set.
426 {
427 // We recalculate the entry here -- we've called out to java since
428 // the last time it was calculated.
429 symbolHandle kn(THREAD, klass->name());
430 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
431 int d_index = dictionary()->hash_to_index(d_hash);
432
433 MutexLocker mu(SystemDictionary_lock, THREAD);
434 {
435 // Note that we have an entry, and entries can be deleted only during GC,
436 // so we cannot allow GC to occur while we're holding this entry.
437
438 // We're using a No_Safepoint_Verifier to catch any place where we
439 // might potentially do a GC at all.
440 // SystemDictionary::do_unloading() asserts that classes are only
441 // unloaded at a safepoint.
442 No_Safepoint_Verifier nosafepoint;
443 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
444 protection_domain, THREAD);
445 }
446 }
447 }
448
449 // We only get here if this thread finds that another thread
450 // has already claimed the placeholder token for the current operation,
451 // but that other thread either never owned or gave up the
452 // object lock
453 // Waits on SystemDictionary_lock to indicate placeholder table updated
454 // On return, caller must recheck placeholder table state
455 //
456 // We only get here if
457 // 1) custom classLoader, i.e. not bootstrap classloader
458 // 2) UnsyncloadClass not set
459 // 3) custom classLoader has broken the class loader objectLock
460 // so another thread got here in parallel
461 //
462 // lockObject must be held.
463 // Complicated dance due to lock ordering:
464 // Must first release the classloader object lock to
465 // allow initial definer to complete the class definition
466 // and to avoid deadlock
467 // Reclaim classloader lock object with same original recursion count
468 // Must release SystemDictionary_lock after notify, since
469 // class loader lock must be claimed before SystemDictionary_lock
470 // to prevent deadlocks
471 //
472 // The notify allows applications that did an untimed wait() on
473 // the classloader object lock to not hang.
474 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
475 assert_lock_strong(SystemDictionary_lock);
476
477 bool calledholdinglock
478 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
479 assert(calledholdinglock,"must hold lock for notify");
480 assert(!UnsyncloadClass, "unexpected double_lock_wait");
481 ObjectSynchronizer::notifyall(lockObject, THREAD);
482 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
483 SystemDictionary_lock->wait();
484 SystemDictionary_lock->unlock();
485 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
486 SystemDictionary_lock->lock();
487 }
488
489 // If the class in is in the placeholder table, class loading is in progress
490 // For cases where the application changes threads to load classes, it
491 // is critical to ClassCircularity detection that we try loading
492 // the superclass on the same thread internally, so we do parallel
493 // super class loading here.
494 // This also is critical in cases where the original thread gets stalled
495 // even in non-circularity situations.
496 // Note: only one thread can define the class, but multiple can resolve
497 // Note: must call resolve_super_or_fail even if null super -
498 // to force placeholder entry creation for this class
499 // Caller must check for pending exception
500 // Returns non-null klassOop if other thread has completed load
501 // and we are done,
502 // If return null klassOop and no pending exception, the caller must load the class
503 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
504 symbolHandle name, symbolHandle superclassname, Handle class_loader,
505 Handle protection_domain, Handle lockObject, TRAPS) {
506
507 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
508 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
509 int d_index = dictionary()->hash_to_index(d_hash);
510 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
511 int p_index = placeholders()->hash_to_index(p_hash);
512
513 // superk is not used, resolve_super called for circularity check only
514 // This code is reached in two situations. One if this thread
515 // is loading the same class twice (e.g. ClassCircularity, or
516 // java.lang.instrument).
517 // The second is if another thread started the resolve_super first
518 // and has not yet finished.
519 // In both cases the original caller will clean up the placeholder
520 // entry on error.
521 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
522 superclassname,
523 class_loader,
524 protection_domain,
525 true,
526 CHECK_(nh));
527 // We don't redefine the class, so we just need to clean up if there
528 // was not an error (don't want to modify any system dictionary
529 // data structures).
530 {
531 MutexLocker mu(SystemDictionary_lock, THREAD);
532 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
533 SystemDictionary_lock->notify_all();
534 }
535
536 // UnsyncloadClass does NOT wait for parallel superclass loads to complete
537 // Bootstrap classloader does wait for parallel superclass loads
538 if (UnsyncloadClass) {
539 MutexLocker mu(SystemDictionary_lock, THREAD);
540 // Check if classloading completed while we were loading superclass or waiting
541 klassOop check = find_class(d_index, d_hash, name, class_loader);
542 if (check != NULL) {
543 // Klass is already loaded, so just return it
544 return(instanceKlassHandle(THREAD, check));
545 } else {
546 return nh;
547 }
548 }
549
550 // must loop to both handle other placeholder updates
551 // and spurious notifications
552 bool super_load_in_progress = true;
553 PlaceholderEntry* placeholder;
554 while (super_load_in_progress) {
555 MutexLocker mu(SystemDictionary_lock, THREAD);
556 // Check if classloading completed while we were loading superclass or waiting
557 klassOop check = find_class(d_index, d_hash, name, class_loader);
558 if (check != NULL) {
559 // Klass is already loaded, so just return it
560 return(instanceKlassHandle(THREAD, check));
561 } else {
562 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
563 if (placeholder && placeholder->super_load_in_progress() ){
564 // Before UnsyncloadClass:
565 // We only get here if the application has released the
566 // classloader lock when another thread was in the middle of loading a
567 // superclass/superinterface for this class, and now
568 // this thread is also trying to load this class.
569 // To minimize surprises, the first thread that started to
570 // load a class should be the one to complete the loading
571 // with the classfile it initially expected.
572 // This logic has the current thread wait once it has done
573 // all the superclass/superinterface loading it can, until
574 // the original thread completes the class loading or fails
575 // If it completes we will use the resulting instanceKlass
576 // which we will find below in the systemDictionary.
577 // We also get here for parallel bootstrap classloader
578 if (class_loader.is_null()) {
579 SystemDictionary_lock->wait();
580 } else {
581 double_lock_wait(lockObject, THREAD);
582 }
583 } else {
584 // If not in SD and not in PH, other thread's load must have failed
585 super_load_in_progress = false;
586 }
587 }
588 }
589 return (nh);
590 }
591
592
593 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
594 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
595 // First check to see if we should remove wrapping L and ;
596 symbolHandle name;
597 if (FieldType::is_obj(class_name())) {
598 ResourceMark rm(THREAD);
599 // Ignore wrapping L and ;.
600 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
601 } else {
602 name = class_name;
603 }
604
605 // UseNewReflection
606 // Fix for 4474172; see evaluation for more details
607 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
608
609 // Do lookup to see if class already exist and the protection domain
610 // has the right access
611 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
612 int d_index = dictionary()->hash_to_index(d_hash);
613 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
614 protection_domain, THREAD);
615 if (probe != NULL) return probe;
616
617
618 // Non-bootstrap class loaders will call out to class loader and
619 // define via jvm/jni_DefineClass which will acquire the
620 // class loader object lock to protect against multiple threads
621 // defining the class in parallel by accident.
622 // This lock must be acquired here so the waiter will find
623 // any successful result in the SystemDictionary and not attempt
624 // the define
625 // Classloaders that support parallelism, e.g. bootstrap classloader,
626 // or all classloaders with UnsyncloadClass do not acquire lock here
627 bool DoObjectLock = true;
628 if (UnsyncloadClass || (class_loader.is_null())) {
629 DoObjectLock = false;
630 }
631
632 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
633 int p_index = placeholders()->hash_to_index(p_hash);
634
635 // Class is not in SystemDictionary so we have to do loading.
636 // Make sure we are synchronized on the class loader before we proceed
637 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
638 check_loader_lock_contention(lockObject, THREAD);
639 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
640
641 // Check again (after locking) if class already exist in SystemDictionary
642 bool class_has_been_loaded = false;
643 bool super_load_in_progress = false;
644 bool havesupername = false;
645 instanceKlassHandle k;
646 PlaceholderEntry* placeholder;
647 symbolHandle superclassname;
648
649 {
650 MutexLocker mu(SystemDictionary_lock, THREAD);
651 klassOop check = find_class(d_index, d_hash, name, class_loader);
652 if (check != NULL) {
653 // Klass is already loaded, so just return it
654 class_has_been_loaded = true;
655 k = instanceKlassHandle(THREAD, check);
656 } else {
657 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
658 if (placeholder && placeholder->super_load_in_progress()) {
659 super_load_in_progress = true;
660 if (placeholder->havesupername() == true) {
661 superclassname = symbolHandle(THREAD, placeholder->supername());
662 havesupername = true;
663 }
664 }
665 }
666 }
667
668 // If the class in is in the placeholder table, class loading is in progress
669 if (super_load_in_progress && havesupername==true) {
670 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
671 class_loader, protection_domain, lockObject, THREAD);
672 if (HAS_PENDING_EXCEPTION) {
673 return NULL;
674 }
675 if (!k.is_null()) {
676 class_has_been_loaded = true;
677 }
678 }
679
680 if (!class_has_been_loaded) {
681
682 // add placeholder entry to record loading instance class
683 // Five cases:
684 // All cases need to prevent modifying bootclasssearchpath
685 // in parallel with a classload of same classname
686 // case 1. traditional classloaders that rely on the classloader object lock
687 // - no other need for LOAD_INSTANCE
688 // case 2. traditional classloaders that break the classloader object lock
689 // as a deadlock workaround. Detection of this case requires that
690 // this check is done while holding the classloader object lock,
691 // and that lock is still held when calling classloader's loadClass.
692 // For these classloaders, we ensure that the first requestor
693 // completes the load and other requestors wait for completion.
694 // case 3. UnsyncloadClass - don't use objectLocker
695 // With this flag, we allow parallel classloading of a
696 // class/classloader pair
697 // case4. Bootstrap classloader - don't own objectLocker
698 // This classloader supports parallelism at the classloader level,
699 // but only allows a single load of a class/classloader pair.
700 // No performance benefit and no deadlock issues.
701 // case 5. Future: parallel user level classloaders - without objectLocker
702 symbolHandle nullsymbolHandle;
703 bool throw_circularity_error = false;
704 {
705 MutexLocker mu(SystemDictionary_lock, THREAD);
706 if (!UnsyncloadClass) {
707 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
708 if (oldprobe) {
709 // only need check_seen_thread once, not on each loop
710 // 6341374 java/lang/Instrument with -Xcomp
711 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
712 throw_circularity_error = true;
713 } else {
714 // case 1: traditional: should never see load_in_progress.
715 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
716
717 // case 4: bootstrap classloader: prevent futile classloading,
718 // wait on first requestor
719 if (class_loader.is_null()) {
720 SystemDictionary_lock->wait();
721 } else {
722 // case 2: traditional with broken classloader lock. wait on first
723 // requestor.
724 double_lock_wait(lockObject, THREAD);
725 }
726 // Check if classloading completed while we were waiting
727 klassOop check = find_class(d_index, d_hash, name, class_loader);
728 if (check != NULL) {
729 // Klass is already loaded, so just return it
730 k = instanceKlassHandle(THREAD, check);
731 class_has_been_loaded = true;
732 }
733 // check if other thread failed to load and cleaned up
734 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
735 }
736 }
737 }
738 }
739 // All cases: add LOAD_INSTANCE
740 // case 3: UnsyncloadClass: allow competing threads to try
741 // LOAD_INSTANCE in parallel
742 // add placeholder entry even if error - callers will remove on error
743 if (!class_has_been_loaded) {
744 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
745 if (throw_circularity_error) {
746 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
747 }
748 // For class loaders that do not acquire the classloader object lock,
749 // if they did not catch another thread holding LOAD_INSTANCE,
750 // need a check analogous to the acquire ObjectLocker/find_class
751 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
752 // one final check if the load has already completed
753 klassOop check = find_class(d_index, d_hash, name, class_loader);
754 if (check != NULL) {
755 // Klass is already loaded, so just return it
756 k = instanceKlassHandle(THREAD, check);
757 class_has_been_loaded = true;
758 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
759 }
760 }
761 }
762 // must throw error outside of owning lock
763 if (throw_circularity_error) {
764 ResourceMark rm(THREAD);
765 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
766 }
767
768 if (!class_has_been_loaded) {
769
770 // Do actual loading
771 k = load_instance_class(name, class_loader, THREAD);
772
773 // In custom class loaders, the usual findClass calls
774 // findLoadedClass, which directly searches the SystemDictionary, then
775 // defineClass. If these are not atomic with respect to other threads,
776 // the findLoadedClass can fail, but the defineClass can get a
777 // LinkageError:: duplicate class definition.
778 // If they got a linkageError, check if a parallel class load succeeded.
779 // If it did, then for bytecode resolution the specification requires
780 // that we return the same result we did for the other thread, i.e. the
781 // successfully loaded instanceKlass
782 // Note: Class can not be unloaded as long as any classloader refs exist
783 // Should not get here for classloaders that support parallelism
784 // with the new cleaner mechanism, e.g. bootstrap classloader
785 if (UnsyncloadClass || (class_loader.is_null())) {
786 if (k.is_null() && HAS_PENDING_EXCEPTION
787 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
788 MutexLocker mu(SystemDictionary_lock, THREAD);
789 klassOop check = find_class(d_index, d_hash, name, class_loader);
790 if (check != NULL) {
791 // Klass is already loaded, so just use it
792 k = instanceKlassHandle(THREAD, check);
793 CLEAR_PENDING_EXCEPTION;
794 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
795 }
796 }
797 }
798
799 // clean up placeholder entries for success or error
800 // This cleans up LOAD_INSTANCE entries
801 // It also cleans up LOAD_SUPER entries on errors from
802 // calling load_instance_class
803 {
804 MutexLocker mu(SystemDictionary_lock, THREAD);
805 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
806 if (probe != NULL) {
807 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
808 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
809 SystemDictionary_lock->notify_all();
810 }
811 }
812
813 // If everything was OK (no exceptions, no null return value), and
814 // class_loader is NOT the defining loader, do a little more bookkeeping.
815 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
816 k->class_loader() != class_loader()) {
817
818 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
819
820 // Need to check for a PENDING_EXCEPTION again; check_constraints
821 // can throw and doesn't use the CHECK macro.
822 if (!HAS_PENDING_EXCEPTION) {
823 { // Grabbing the Compile_lock prevents systemDictionary updates
824 // during compilations.
825 MutexLocker mu(Compile_lock, THREAD);
826 update_dictionary(d_index, d_hash, p_index, p_hash,
827 k, class_loader, THREAD);
828 }
829 if (JvmtiExport::should_post_class_load()) {
830 Thread *thread = THREAD;
831 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
832 JvmtiExport::post_class_load((JavaThread *) thread, k());
833 }
834 }
835 }
836 if (HAS_PENDING_EXCEPTION || k.is_null()) {
837 // On error, clean up placeholders
838 {
839 MutexLocker mu(SystemDictionary_lock, THREAD);
840 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
841 SystemDictionary_lock->notify_all();
842 }
843 return NULL;
844 }
845 }
846 }
847
848 #ifdef ASSERT
849 {
850 Handle loader (THREAD, k->class_loader());
851 MutexLocker mu(SystemDictionary_lock, THREAD);
852 oop kk = find_class_or_placeholder(name, loader);
853 assert(kk == k(), "should be present in dictionary");
854 }
855 #endif
856
857 // return if the protection domain in NULL
858 if (protection_domain() == NULL) return k();
859
860 // Check the protection domain has the right access
861 {
862 MutexLocker mu(SystemDictionary_lock, THREAD);
863 // Note that we have an entry, and entries can be deleted only during GC,
864 // so we cannot allow GC to occur while we're holding this entry.
865 // We're using a No_Safepoint_Verifier to catch any place where we
866 // might potentially do a GC at all.
867 // SystemDictionary::do_unloading() asserts that classes are only
868 // unloaded at a safepoint.
869 No_Safepoint_Verifier nosafepoint;
870 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
871 class_loader,
872 protection_domain)) {
873 return k();
874 }
875 }
876
877 // Verify protection domain. If it fails an exception is thrown
878 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
879
880 return k();
881 }
882
883
884 // This routine does not lock the system dictionary.
885 //
886 // Since readers don't hold a lock, we must make sure that system
887 // dictionary entries are only removed at a safepoint (when only one
888 // thread is running), and are added to in a safe way (all links must
889 // be updated in an MT-safe manner).
890 //
891 // Callers should be aware that an entry could be added just after
892 // _dictionary->bucket(index) is read here, so the caller will not see
893 // the new entry.
894
895 klassOop SystemDictionary::find(symbolHandle class_name,
896 Handle class_loader,
897 Handle protection_domain,
898 TRAPS) {
899
900 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
901 int d_index = dictionary()->hash_to_index(d_hash);
902
903 {
904 // Note that we have an entry, and entries can be deleted only during GC,
905 // so we cannot allow GC to occur while we're holding this entry.
906 // We're using a No_Safepoint_Verifier to catch any place where we
907 // might potentially do a GC at all.
908 // SystemDictionary::do_unloading() asserts that classes are only
909 // unloaded at a safepoint.
910 No_Safepoint_Verifier nosafepoint;
911 return dictionary()->find(d_index, d_hash, class_name, class_loader,
912 protection_domain, THREAD);
913 }
914 }
915
916
917 // Look for a loaded instance or array klass by name. Do not do any loading.
918 // return NULL in case of error.
919 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
920 Handle class_loader,
921 Handle protection_domain,
922 TRAPS) {
923 klassOop k = NULL;
924 assert(class_name() != NULL, "class name must be non NULL");
925 if (FieldType::is_array(class_name())) {
926 // The name refers to an array. Parse the name.
927 jint dimension;
928 symbolOop object_key;
929
930 // dimension and object_key are assigned as a side-effect of this call
931 BasicType t = FieldType::get_array_info(class_name(), &dimension,
932 &object_key, CHECK_(NULL));
933 if (t != T_OBJECT) {
934 k = Universe::typeArrayKlassObj(t);
935 } else {
936 symbolHandle h_key(THREAD, object_key);
937 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
938 }
939 if (k != NULL) {
940 k = Klass::cast(k)->array_klass_or_null(dimension);
941 }
942 } else {
943 k = find(class_name, class_loader, protection_domain, THREAD);
944 }
945 return k;
946 }
947
948 // Note: this method is much like resolve_from_stream, but
949 // updates no supplemental data structures.
950 // TODO consolidate the two methods with a helper routine?
951 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
952 Handle class_loader,
953 Handle protection_domain,
954 ClassFileStream* st,
955 TRAPS) {
956 symbolHandle parsed_name;
957
958 // Parse the stream. Note that we do this even though this klass might
959 // already be present in the SystemDictionary, otherwise we would not
960 // throw potential ClassFormatErrors.
961 //
962 // Note: "name" is updated.
963 // Further note: a placeholder will be added for this class when
964 // super classes are loaded (resolve_super_or_fail). We expect this
965 // to be called for all classes but java.lang.Object; and we preload
966 // java.lang.Object through resolve_or_fail, not this path.
967
968 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
969 class_loader,
970 protection_domain,
971 parsed_name,
972 THREAD);
973
974
975 // We don't redefine the class, so we just need to clean up whether there
976 // was an error or not (don't want to modify any system dictionary
977 // data structures).
978 // Parsed name could be null if we threw an error before we got far
979 // enough along to parse it -- in that case, there is nothing to clean up.
980 if (!parsed_name.is_null()) {
981 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
982 class_loader);
983 int p_index = placeholders()->hash_to_index(p_hash);
984 {
985 MutexLocker mu(SystemDictionary_lock, THREAD);
986 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
987 SystemDictionary_lock->notify_all();
988 }
989 }
990
991 return k();
992 }
993
994 // Add a klass to the system from a stream (called by jni_DefineClass and
995 // JVM_DefineClass).
996 // Note: class_name can be NULL. In that case we do not know the name of
997 // the class until we have parsed the stream.
998
999 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
1000 Handle class_loader,
1001 Handle protection_domain,
1002 ClassFileStream* st,
1003 TRAPS) {
1004
1005 // Make sure we are synchronized on the class loader before we initiate
1006 // loading.
1007 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1008 check_loader_lock_contention(lockObject, THREAD);
1009 ObjectLocker ol(lockObject, THREAD);
1010
1011 symbolHandle parsed_name;
1012
1013 // Parse the stream. Note that we do this even though this klass might
1014 // already be present in the SystemDictionary, otherwise we would not
1015 // throw potential ClassFormatErrors.
1016 //
1017 // Note: "name" is updated.
1018 // Further note: a placeholder will be added for this class when
1019 // super classes are loaded (resolve_super_or_fail). We expect this
1020 // to be called for all classes but java.lang.Object; and we preload
1021 // java.lang.Object through resolve_or_fail, not this path.
1022
1023 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1024 class_loader,
1025 protection_domain,
1026 parsed_name,
1027 THREAD);
1028
1029 const char* pkg = "java/";
1030 if (!HAS_PENDING_EXCEPTION &&
1031 !class_loader.is_null() &&
1032 !parsed_name.is_null() &&
1033 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1034 // It is illegal to define classes in the "java." package from
1035 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1036 ResourceMark rm(THREAD);
1037 char* name = parsed_name->as_C_string();
1038 char* index = strrchr(name, '/');
1039 *index = '\0'; // chop to just the package name
1040 while ((index = strchr(name, '/')) != NULL) {
1041 *index = '.'; // replace '/' with '.' in package name
1042 }
1043 const char* fmt = "Prohibited package name: %s";
1044 size_t len = strlen(fmt) + strlen(name);
1045 char* message = NEW_RESOURCE_ARRAY(char, len);
1046 jio_snprintf(message, len, fmt, name);
1047 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1048 vmSymbols::java_lang_SecurityException(), message);
1049 }
1050
1051 if (!HAS_PENDING_EXCEPTION) {
1052 assert(!parsed_name.is_null(), "Sanity");
1053 assert(class_name.is_null() || class_name() == parsed_name(),
1054 "name mismatch");
1055 // Verification prevents us from creating names with dots in them, this
1056 // asserts that that's the case.
1057 assert(is_internal_format(parsed_name),
1058 "external class name format used internally");
1059
1060 // Add class just loaded
1061 define_instance_class(k, THREAD);
1062 }
1063
1064 // If parsing the class file or define_instance_class failed, we
1065 // need to remove the placeholder added on our behalf. But we
1066 // must make sure parsed_name is valid first (it won't be if we had
1067 // a format error before the class was parsed far enough to
1068 // find the name).
1069 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1070 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1071 class_loader);
1072 int p_index = placeholders()->hash_to_index(p_hash);
1073 {
1074 MutexLocker mu(SystemDictionary_lock, THREAD);
1075 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1076 SystemDictionary_lock->notify_all();
1077 }
1078 return NULL;
1079 }
1080
1081 // Make sure that we didn't leave a place holder in the
1082 // SystemDictionary; this is only done on success
1083 debug_only( {
1084 if (!HAS_PENDING_EXCEPTION) {
1085 assert(!parsed_name.is_null(), "parsed_name is still null?");
1086 symbolHandle h_name (THREAD, k->name());
1087 Handle h_loader (THREAD, k->class_loader());
1088
1089 MutexLocker mu(SystemDictionary_lock, THREAD);
1090
1091 oop check = find_class_or_placeholder(parsed_name, class_loader);
1092 assert(check == k(), "should be present in the dictionary");
1093
1094 oop check2 = find_class_or_placeholder(h_name, h_loader);
1095 assert(check == check2, "name inconsistancy in SystemDictionary");
1096 }
1097 } );
1098
1099 return k();
1100 }
1101
1102
1103 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1104 int number_of_entries) {
1105 assert(length == _nof_buckets * sizeof(HashtableBucket),
1106 "bad shared dictionary size.");
1107 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1108 }
1109
1110
1111 // If there is a shared dictionary, then find the entry for the
1112 // given shared system class, if any.
1113
1114 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1115 if (shared_dictionary() != NULL) {
1116 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1117 int d_index = dictionary()->hash_to_index(d_hash);
1118 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1119 } else {
1120 return NULL;
1121 }
1122 }
1123
1124
1125 // Load a class from the shared spaces (found through the shared system
1126 // dictionary). Force the superclass and all interfaces to be loaded.
1127 // Update the class definition to include sibling classes and no
1128 // subclasses (yet). [Classes in the shared space are not part of the
1129 // object hierarchy until loaded.]
1130
1131 instanceKlassHandle SystemDictionary::load_shared_class(
1132 symbolHandle class_name, Handle class_loader, TRAPS) {
1133 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1134 return load_shared_class(ik, class_loader, THREAD);
1135 }
1136
1137 // Note well! Changes to this method may affect oop access order
1138 // in the shared archive. Please take care to not make changes that
1139 // adversely affect cold start time by changing the oop access order
1140 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1141 // MarkAndMoveOrderedReadWrite closures.
1142 instanceKlassHandle SystemDictionary::load_shared_class(
1143 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1144 assert(class_loader.is_null(), "non-null classloader for shared class?");
1145 if (ik.not_null()) {
1146 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1147 symbolHandle class_name(THREAD, ik->name());
1148
1149 // Found the class, now load the superclass and interfaces. If they
1150 // are shared, add them to the main system dictionary and reset
1151 // their hierarchy references (supers, subs, and interfaces).
1152
1153 if (ik->super() != NULL) {
1154 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1155 resolve_super_or_fail(class_name, cn,
1156 class_loader, Handle(), true, CHECK_(nh));
1157 }
1158
1159 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1160 int num_interfaces = interfaces->length();
1161 for (int index = 0; index < num_interfaces; index++) {
1162 klassOop k = klassOop(interfaces->obj_at(index));
1163
1164 // Note: can not use instanceKlass::cast here because
1165 // interfaces' instanceKlass's C++ vtbls haven't been
1166 // reinitialized yet (they will be once the interface classes
1167 // are loaded)
1168 symbolHandle name (THREAD, k->klass_part()->name());
1169 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1170 }
1171
1172 // Adjust methods to recover missing data. They need addresses for
1173 // interpreter entry points and their default native method address
1174 // must be reset.
1175
1176 // Updating methods must be done under a lock so multiple
1177 // threads don't update these in parallel
1178 // Shared classes are all currently loaded by the bootstrap
1179 // classloader, so this will never cause a deadlock on
1180 // a custom class loader lock.
1181
1182 {
1183 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1184 check_loader_lock_contention(lockObject, THREAD);
1185 ObjectLocker ol(lockObject, THREAD, true);
1186
1187 objArrayHandle methods (THREAD, ik->methods());
1188 int num_methods = methods->length();
1189 for (int index2 = 0; index2 < num_methods; ++index2) {
1190 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1191 m()->link_method(m, CHECK_(nh));
1192 }
1193 }
1194
1195 if (TraceClassLoading) {
1196 ResourceMark rm;
1197 tty->print("[Loaded %s", ik->external_name());
1198 tty->print(" from shared objects file");
1199 tty->print_cr("]");
1200 }
1201 // notify a class loaded from shared object
1202 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1203 true /* shared class */);
1204 }
1205 return ik;
1206 }
1207
1208 #ifdef KERNEL
1209 // Some classes on the bootstrap class path haven't been installed on the
1210 // system yet. Call the DownloadManager method to make them appear in the
1211 // bootstrap class path and try again to load the named class.
1212 // Note that with delegation class loaders all classes in another loader will
1213 // first try to call this so it'd better be fast!!
1214 static instanceKlassHandle download_and_retry_class_load(
1215 symbolHandle class_name,
1216 TRAPS) {
1217
1218 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1219 instanceKlassHandle nk;
1220
1221 // If download manager class isn't loaded just return.
1222 if (dlm == NULL) return nk;
1223
1224 { HandleMark hm(THREAD);
1225 ResourceMark rm(THREAD);
1226 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1227 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1228
1229 // return value
1230 JavaValue result(T_OBJECT);
1231
1232 // Call the DownloadManager. We assume that it has a lock because
1233 // multiple classes could be not found and downloaded at the same time.
1234 // class sun.misc.DownloadManager;
1235 // public static String getBootClassPathEntryForClass(String className);
1236 JavaCalls::call_static(&result,
1237 KlassHandle(THREAD, dlm),
1238 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1239 vmSymbolHandles::string_string_signature(),
1240 class_string,
1241 CHECK_(nk));
1242
1243 // Get result.string and add to bootclasspath
1244 assert(result.get_type() == T_OBJECT, "just checking");
1245 oop obj = (oop) result.get_jobject();
1246 if (obj == NULL) { return nk; }
1247
1248 Handle h_obj(THREAD, obj);
1249 char* new_class_name = java_lang_String::as_platform_dependent_str(h_obj,
1250 CHECK_(nk));
1251
1252 // lock the loader
1253 // we use this lock because JVMTI does.
1254 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1255
1256 ObjectLocker ol(loader_lock, THREAD);
1257 // add the file to the bootclasspath
1258 ClassLoader::update_class_path_entry_list(new_class_name, true);
1259 } // end HandleMark
1260
1261 if (TraceClassLoading) {
1262 ClassLoader::print_bootclasspath();
1263 }
1264 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1265 }
1266 #endif // KERNEL
1267
1268
1269 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1270 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1271 if (class_loader.is_null()) {
1272 // Search the shared system dictionary for classes preloaded into the
1273 // shared spaces.
1274 instanceKlassHandle k;
1275 k = load_shared_class(class_name, class_loader, THREAD);
1276
1277 if (k.is_null()) {
1278 // Use VM class loader
1279 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1280 }
1281
1282 #ifdef KERNEL
1283 // If the VM class loader has failed to load the class, call the
1284 // DownloadManager class to make it magically appear on the classpath
1285 // and try again. This is only configured with the Kernel VM.
1286 if (k.is_null()) {
1287 k = download_and_retry_class_load(class_name, CHECK_(nh));
1288 }
1289 #endif // KERNEL
1290
1291 // find_or_define_instance_class may return a different k
1292 if (!k.is_null()) {
1293 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1294 }
1295 return k;
1296 } else {
1297 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1298 ResourceMark rm(THREAD);
1299
1300 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1301 // Translate to external class name format, i.e., convert '/' chars to '.'
1302 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1303
1304 JavaValue result(T_OBJECT);
1305
1306 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1307
1308 // UnsyncloadClass option means don't synchronize loadClass() calls.
1309 // loadClassInternal() is synchronized and public loadClass(String) is not.
1310 // This flag is for diagnostic purposes only. It is risky to call
1311 // custom class loaders without synchronization.
1312 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1313 // findClass, this flag risks unexpected timing bugs in the field.
1314 // Do NOT assume this will be supported in future releases.
1315 if (!UnsyncloadClass && has_loadClassInternal()) {
1316 JavaCalls::call_special(&result,
1317 class_loader,
1318 spec_klass,
1319 vmSymbolHandles::loadClassInternal_name(),
1320 vmSymbolHandles::string_class_signature(),
1321 string,
1322 CHECK_(nh));
1323 } else {
1324 JavaCalls::call_virtual(&result,
1325 class_loader,
1326 spec_klass,
1327 vmSymbolHandles::loadClass_name(),
1328 vmSymbolHandles::string_class_signature(),
1329 string,
1330 CHECK_(nh));
1331 }
1332
1333 assert(result.get_type() == T_OBJECT, "just checking");
1334 oop obj = (oop) result.get_jobject();
1335
1336 // Primitive classes return null since forName() can not be
1337 // used to obtain any of the Class objects representing primitives or void
1338 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1339 instanceKlassHandle k =
1340 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1341 // For user defined Java class loaders, check that the name returned is
1342 // the same as that requested. This check is done for the bootstrap
1343 // loader when parsing the class file.
1344 if (class_name() == k->name()) {
1345 return k;
1346 }
1347 }
1348 // Class is not found or has the wrong name, return NULL
1349 return nh;
1350 }
1351 }
1352
1353 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1354
1355 Handle class_loader_h(THREAD, k->class_loader());
1356
1357 // for bootstrap classloader don't acquire lock
1358 if (!class_loader_h.is_null()) {
1359 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1360 compute_loader_lock_object(class_loader_h, THREAD)),
1361 "define called without lock");
1362 }
1363
1364
1365 // Check class-loading constraints. Throw exception if violation is detected.
1366 // Grabs and releases SystemDictionary_lock
1367 // The check_constraints/find_class call and update_dictionary sequence
1368 // must be "atomic" for a specific class/classloader pair so we never
1369 // define two different instanceKlasses for that class/classloader pair.
1370 // Existing classloaders will call define_instance_class with the
1371 // classloader lock held
1372 // Parallel classloaders will call find_or_define_instance_class
1373 // which will require a token to perform the define class
1374 symbolHandle name_h(THREAD, k->name());
1375 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1376 int d_index = dictionary()->hash_to_index(d_hash);
1377 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1378
1379 // Register class just loaded with class loader (placed in Vector)
1380 // Note we do this before updating the dictionary, as this can
1381 // fail with an OutOfMemoryError (if it does, we will *not* put this
1382 // class in the dictionary and will not update the class hierarchy).
1383 if (k->class_loader() != NULL) {
1384 methodHandle m(THREAD, Universe::loader_addClass_method());
1385 JavaValue result(T_VOID);
1386 JavaCallArguments args(class_loader_h);
1387 args.push_oop(Handle(THREAD, k->java_mirror()));
1388 JavaCalls::call(&result, m, &args, CHECK);
1389 }
1390
1391 // Add the new class. We need recompile lock during update of CHA.
1392 {
1393 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1394 int p_index = placeholders()->hash_to_index(p_hash);
1395
1396 MutexLocker mu_r(Compile_lock, THREAD);
1397
1398 // Add to class hierarchy, initialize vtables, and do possible
1399 // deoptimizations.
1400 add_to_hierarchy(k, CHECK); // No exception, but can block
1401
1402 // Add to systemDictionary - so other classes can see it.
1403 // Grabs and releases SystemDictionary_lock
1404 update_dictionary(d_index, d_hash, p_index, p_hash,
1405 k, class_loader_h, THREAD);
1406 }
1407 k->eager_initialize(THREAD);
1408
1409 // notify jvmti
1410 if (JvmtiExport::should_post_class_load()) {
1411 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1412 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1413
1414 }
1415 }
1416
1417 // Support parallel classloading
1418 // Initial implementation for bootstrap classloader
1419 // For future:
1420 // For custom class loaders that support parallel classloading,
1421 // in case they do not synchronize around
1422 // FindLoadedClass/DefineClass calls, we check for parallel
1423 // loading for them, wait if a defineClass is in progress
1424 // and return the initial requestor's results
1425 // For better performance, the class loaders should synchronize
1426 // findClass(), i.e. FindLoadedClass/DefineClass or they
1427 // potentially waste time reading and parsing the bytestream.
1428 // Note: VM callers should ensure consistency of k/class_name,class_loader
1429 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1430
1431 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1432
1433 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1434 int d_index = dictionary()->hash_to_index(d_hash);
1435
1436 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1437 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1438 int p_index = placeholders()->hash_to_index(p_hash);
1439 PlaceholderEntry* probe;
1440
1441 {
1442 MutexLocker mu(SystemDictionary_lock, THREAD);
1443 // First check if class already defined
1444 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1445 if (check != NULL) {
1446 return(instanceKlassHandle(THREAD, check));
1447 }
1448
1449 // Acquire define token for this class/classloader
1450 symbolHandle nullsymbolHandle;
1451 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1452 // Check if another thread defining in parallel
1453 if (probe->definer() == NULL) {
1454 // Thread will define the class
1455 probe->set_definer(THREAD);
1456 } else {
1457 // Wait for defining thread to finish and return results
1458 while (probe->definer() != NULL) {
1459 SystemDictionary_lock->wait();
1460 }
1461 if (probe->instanceKlass() != NULL) {
1462 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1463 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1464 } else {
1465 // If definer had an error, try again as any new thread would
1466 probe->set_definer(THREAD);
1467 #ifdef ASSERT
1468 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1469 assert(check == NULL, "definer missed recording success");
1470 #endif
1471 }
1472 }
1473 }
1474
1475 define_instance_class(k, THREAD);
1476
1477 Handle linkage_exception = Handle(); // null handle
1478
1479 // definer must notify any waiting threads
1480 {
1481 MutexLocker mu(SystemDictionary_lock, THREAD);
1482 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader);
1483 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1484 if (probe != NULL) {
1485 if (HAS_PENDING_EXCEPTION) {
1486 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1487 CLEAR_PENDING_EXCEPTION;
1488 } else {
1489 probe->set_instanceKlass(k());
1490 }
1491 probe->set_definer(NULL);
1492 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1493 SystemDictionary_lock->notify_all();
1494 }
1495 }
1496
1497 // Can't throw exception while holding lock due to rank ordering
1498 if (linkage_exception() != NULL) {
1499 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1500 }
1501
1502 return k;
1503 }
1504
1505 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1506 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1507 if (class_loader.is_null()) {
1508 return Handle(THREAD, _system_loader_lock_obj);
1509 } else {
1510 return class_loader;
1511 }
1512 }
1513
1514 // This method is added to check how often we have to wait to grab loader
1515 // lock. The results are being recorded in the performance counters defined in
1516 // ClassLoader::_sync_systemLoaderLockContentionRate and
1517 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1518 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1519 if (!UsePerfData) {
1520 return;
1521 }
1522
1523 assert(!loader_lock.is_null(), "NULL lock object");
1524
1525 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1526 == ObjectSynchronizer::owner_other) {
1527 // contention will likely happen, so increment the corresponding
1528 // contention counter.
1529 if (loader_lock() == _system_loader_lock_obj) {
1530 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1531 } else {
1532 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1533 }
1534 }
1535 }
1536
1537 // ----------------------------------------------------------------------------
1538 // Lookup
1539
1540 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1541 symbolHandle class_name,
1542 Handle class_loader) {
1543 assert_locked_or_safepoint(SystemDictionary_lock);
1544 assert (index == dictionary()->index_for(class_name, class_loader),
1545 "incorrect index?");
1546
1547 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1548 return k;
1549 }
1550
1551
1552 // Basic find on classes in the midst of being loaded
1553 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1554 symbolHandle class_name,
1555 Handle class_loader) {
1556 assert_locked_or_safepoint(SystemDictionary_lock);
1557
1558 return placeholders()->find_entry(index, hash, class_name, class_loader);
1559 }
1560
1561
1562 // Used for assertions and verification only
1563 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1564 Handle class_loader) {
1565 #ifndef ASSERT
1566 guarantee(VerifyBeforeGC ||
1567 VerifyDuringGC ||
1568 VerifyBeforeExit ||
1569 VerifyAfterGC, "too expensive");
1570 #endif
1571 assert_locked_or_safepoint(SystemDictionary_lock);
1572 symbolOop class_name_ = class_name();
1573 oop class_loader_ = class_loader();
1574
1575 // First look in the loaded class array
1576 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1577 int d_index = dictionary()->hash_to_index(d_hash);
1578 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1579
1580 if (lookup == NULL) {
1581 // Next try the placeholders
1582 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1583 int p_index = placeholders()->hash_to_index(p_hash);
1584 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1585 }
1586
1587 return lookup;
1588 }
1589
1590
1591 // Get the next class in the diictionary.
1592 klassOop SystemDictionary::try_get_next_class() {
1593 return dictionary()->try_get_next_class();
1594 }
1595
1596
1597 // ----------------------------------------------------------------------------
1598 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1599 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1600 // before a new class is used.
1601
1602 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1603 assert(k.not_null(), "just checking");
1604 // Link into hierachy. Make sure the vtables are initialized before linking into
1605 k->append_to_sibling_list(); // add to superklass/sibling list
1606 k->process_interfaces(THREAD); // handle all "implements" declarations
1607 k->set_init_state(instanceKlass::loaded);
1608 // Now flush all code that depended on old class hierarchy.
1609 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1610 // Also, first reinitialize vtable because it may have gotten out of synch
1611 // while the new class wasn't connected to the class hierarchy.
1612 Universe::flush_dependents_on(k);
1613 }
1614
1615
1616 // ----------------------------------------------------------------------------
1617 // GC support
1618
1619 // Following roots during mark-sweep is separated in two phases.
1620 //
1621 // The first phase follows preloaded classes and all other system
1622 // classes, since these will never get unloaded anyway.
1623 //
1624 // The second phase removes (unloads) unreachable classes from the
1625 // system dictionary and follows the remaining classes' contents.
1626
1627 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1628 // Follow preloaded classes/mirrors and system loader object
1629 blk->do_oop(&_java_system_loader);
1630 preloaded_oops_do(blk);
1631 always_strong_classes_do(blk);
1632 }
1633
1634
1635 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1636 // Follow all system classes and temporary placeholders in dictionary
1637 dictionary()->always_strong_classes_do(blk);
1638
1639 // Placeholders. These are *always* strong roots, as they
1640 // represent classes we're actively loading.
1641 placeholders_do(blk);
1642
1643 // Loader constraints. We must keep the symbolOop used in the name alive.
1644 constraints()->always_strong_classes_do(blk);
1645
1646 // Resolution errors keep the symbolOop for the error alive
1647 resolution_errors()->always_strong_classes_do(blk);
1648 }
1649
1650
1651 void SystemDictionary::placeholders_do(OopClosure* blk) {
1652 placeholders()->oops_do(blk);
1653 }
1654
1655
1656 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1657 bool result = dictionary()->do_unloading(is_alive);
1658 constraints()->purge_loader_constraints(is_alive);
1659 resolution_errors()->purge_resolution_errors(is_alive);
1660 return result;
1661 }
1662
1663
1664 // The mirrors are scanned by shared_oops_do() which is
1665 // not called by oops_do(). In order to process oops in
1666 // a necessary order, shared_oops_do() is call by
1667 // Universe::oops_do().
1668 void SystemDictionary::oops_do(OopClosure* f) {
1669 // Adjust preloaded classes and system loader object
1670 f->do_oop(&_java_system_loader);
1671 preloaded_oops_do(f);
1672
1673 lazily_loaded_oops_do(f);
1674
1675 // Adjust dictionary
1676 dictionary()->oops_do(f);
1677
1678 // Partially loaded classes
1679 placeholders()->oops_do(f);
1680
1681 // Adjust constraint table
1682 constraints()->oops_do(f);
1683
1684 // Adjust resolution error table
1685 resolution_errors()->oops_do(f);
1686 }
1687
1688
1689 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1690 f->do_oop((oop*) &_string_klass);
1691 f->do_oop((oop*) &_object_klass);
1692 f->do_oop((oop*) &_class_klass);
1693 f->do_oop((oop*) &_cloneable_klass);
1694 f->do_oop((oop*) &_classloader_klass);
1695 f->do_oop((oop*) &_serializable_klass);
1696 f->do_oop((oop*) &_system_klass);
1697
1698 f->do_oop((oop*) &_throwable_klass);
1699 f->do_oop((oop*) &_error_klass);
1700 f->do_oop((oop*) &_threaddeath_klass);
1701 f->do_oop((oop*) &_exception_klass);
1702 f->do_oop((oop*) &_runtime_exception_klass);
1703 f->do_oop((oop*) &_classNotFoundException_klass);
1704 f->do_oop((oop*) &_noClassDefFoundError_klass);
1705 f->do_oop((oop*) &_linkageError_klass);
1706 f->do_oop((oop*) &_classCastException_klass);
1707 f->do_oop((oop*) &_arrayStoreException_klass);
1708 f->do_oop((oop*) &_virtualMachineError_klass);
1709 f->do_oop((oop*) &_outOfMemoryError_klass);
1710 f->do_oop((oop*) &_StackOverflowError_klass);
1711 f->do_oop((oop*) &_illegalMonitorStateException_klass);
1712 f->do_oop((oop*) &_protectionDomain_klass);
1713 f->do_oop((oop*) &_AccessControlContext_klass);
1714
1715 f->do_oop((oop*) &_reference_klass);
1716 f->do_oop((oop*) &_soft_reference_klass);
1717 f->do_oop((oop*) &_weak_reference_klass);
1718 f->do_oop((oop*) &_final_reference_klass);
1719 f->do_oop((oop*) &_phantom_reference_klass);
1720 f->do_oop((oop*) &_finalizer_klass);
1721
1722 f->do_oop((oop*) &_thread_klass);
1723 f->do_oop((oop*) &_threadGroup_klass);
1724 f->do_oop((oop*) &_properties_klass);
1725 f->do_oop((oop*) &_reflect_accessible_object_klass);
1726 f->do_oop((oop*) &_reflect_field_klass);
1727 f->do_oop((oop*) &_reflect_method_klass);
1728 f->do_oop((oop*) &_reflect_constructor_klass);
1729 f->do_oop((oop*) &_reflect_magic_klass);
1730 f->do_oop((oop*) &_reflect_method_accessor_klass);
1731 f->do_oop((oop*) &_reflect_constructor_accessor_klass);
1732 f->do_oop((oop*) &_reflect_delegating_classloader_klass);
1733 f->do_oop((oop*) &_reflect_constant_pool_klass);
1734 f->do_oop((oop*) &_reflect_unsafe_static_field_accessor_impl_klass);
1735
1736 f->do_oop((oop*) &_stringBuffer_klass);
1737 f->do_oop((oop*) &_vector_klass);
1738 f->do_oop((oop*) &_hashtable_klass);
1739
1740 f->do_oop((oop*) &_stackTraceElement_klass);
1741
1742 f->do_oop((oop*) &_java_nio_Buffer_klass);
1743
1744 f->do_oop((oop*) &_sun_misc_AtomicLongCSImpl_klass);
1745 f->do_oop((oop*) &_sun_jkernel_DownloadManager_klass);
1746
1747 f->do_oop((oop*) &_boolean_klass);
1748 f->do_oop((oop*) &_char_klass);
1749 f->do_oop((oop*) &_float_klass);
1750 f->do_oop((oop*) &_double_klass);
1751 f->do_oop((oop*) &_byte_klass);
1752 f->do_oop((oop*) &_short_klass);
1753 f->do_oop((oop*) &_int_klass);
1754 f->do_oop((oop*) &_long_klass);
1755 {
1756 for (int i = 0; i < T_VOID+1; i++) {
1757 if (_box_klasses[i] != NULL) {
1758 assert(i >= T_BOOLEAN, "checking");
1759 f->do_oop((oop*) &_box_klasses[i]);
1760 }
1761 }
1762 }
1763
1764 // The basic type mirrors would have already been processed in
1765 // Universe::oops_do(), via a call to shared_oops_do(), so should
1766 // not be processed again.
1767
1768 f->do_oop((oop*) &_system_loader_lock_obj);
1769 FilteredFieldsMap::klasses_oops_do(f);
1770 }
1771
1772 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1773 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1774 }
1775
1776 // Just the classes from defining class loaders
1777 // Don't iterate over placeholders
1778 void SystemDictionary::classes_do(void f(klassOop)) {
1779 dictionary()->classes_do(f);
1780 }
1781
1782 // Added for initialize_itable_for_klass
1783 // Just the classes from defining class loaders
1784 // Don't iterate over placeholders
1785 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1786 dictionary()->classes_do(f, CHECK);
1787 }
1788
1789 // All classes, and their class loaders
1790 // Don't iterate over placeholders
1791 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1792 dictionary()->classes_do(f);
1793 }
1794
1795 // All classes, and their class loaders
1796 // (added for helpers that use HandleMarks and ResourceMarks)
1797 // Don't iterate over placeholders
1798 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1799 dictionary()->classes_do(f, CHECK);
1800 }
1801
1802 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1803 placeholders()->entries_do(f);
1804 }
1805
1806 void SystemDictionary::methods_do(void f(methodOop)) {
1807 dictionary()->methods_do(f);
1808 }
1809
1810 // ----------------------------------------------------------------------------
1811 // Lazily load klasses
1812
1813 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1814 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1815
1816 // if multiple threads calling this function, only one thread will load
1817 // the class. The other threads will find the loaded version once the
1818 // class is loaded.
1819 klassOop aos = _abstract_ownable_synchronizer_klass;
1820 if (aos == NULL) {
1821 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1822 // Force a fence to prevent any read before the write completes
1823 OrderAccess::fence();
1824 _abstract_ownable_synchronizer_klass = k;
1825 }
1826 }
1827
1828 // ----------------------------------------------------------------------------
1829 // Initialization
1830
1831 void SystemDictionary::initialize(TRAPS) {
1832 // Allocate arrays
1833 assert(dictionary() == NULL,
1834 "SystemDictionary should only be initialized once");
1835 _dictionary = new Dictionary(_nof_buckets);
1836 _placeholders = new PlaceholderTable(_nof_buckets);
1837 _number_of_modifications = 0;
1838 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1839 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1840
1841 // Allocate private object used as system class loader lock
1842 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1843 // Initialize basic classes
1844 initialize_preloaded_classes(CHECK);
1845 }
1846
1847
1848 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1849 assert(_object_klass == NULL, "preloaded classes should only be initialized once");
1850 // Preload commonly used klasses
1851 _object_klass = resolve_or_fail(vmSymbolHandles::java_lang_Object(), true, CHECK);
1852 _string_klass = resolve_or_fail(vmSymbolHandles::java_lang_String(), true, CHECK);
1853 _class_klass = resolve_or_fail(vmSymbolHandles::java_lang_Class(), true, CHECK);
1854 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(_class_klass));
1855 // Fixup mirrors for classes loaded before java.lang.Class.
1856 // These calls iterate over the objects currently in the perm gen
1857 // so calling them at this point is matters (not before when there
1858 // are fewer objects and not later after there are more objects
1859 // in the perm gen.
1860 Universe::initialize_basic_type_mirrors(CHECK);
1861 Universe::fixup_mirrors(CHECK);
1862
1863 _cloneable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Cloneable(), true, CHECK);
1864 _classloader_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassLoader(), true, CHECK);
1865 _serializable_klass = resolve_or_fail(vmSymbolHandles::java_io_Serializable(), true, CHECK);
1866 _system_klass = resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
1867
1868 _throwable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Throwable(), true, CHECK);
1869 _error_klass = resolve_or_fail(vmSymbolHandles::java_lang_Error(), true, CHECK);
1870 _threaddeath_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadDeath(), true, CHECK);
1871 _exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_Exception(), true, CHECK);
1872 _runtime_exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_RuntimeException(), true, CHECK);
1873 _protectionDomain_klass = resolve_or_fail(vmSymbolHandles::java_security_ProtectionDomain(), true, CHECK);
1874 _AccessControlContext_klass = resolve_or_fail(vmSymbolHandles::java_security_AccessControlContext(), true, CHECK);
1875 _classNotFoundException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassNotFoundException(), true, CHECK);
1876 _noClassDefFoundError_klass = resolve_or_fail(vmSymbolHandles::java_lang_NoClassDefFoundError(), true, CHECK);
1877 _linkageError_klass = resolve_or_fail(vmSymbolHandles::java_lang_LinkageError(), true, CHECK);
1878 _classCastException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassCastException(), true, CHECK);
1879 _arrayStoreException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ArrayStoreException(), true, CHECK);
1880 _virtualMachineError_klass = resolve_or_fail(vmSymbolHandles::java_lang_VirtualMachineError(), true, CHECK);
1881 _outOfMemoryError_klass = resolve_or_fail(vmSymbolHandles::java_lang_OutOfMemoryError(), true, CHECK);
1882 _StackOverflowError_klass = resolve_or_fail(vmSymbolHandles::java_lang_StackOverflowError(), true, CHECK);
1883 _illegalMonitorStateException_klass = resolve_or_fail(vmSymbolHandles::java_lang_IllegalMonitorStateException(), true, CHECK);
1884
1885 // Preload ref klasses and set reference types
1886 _reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Reference(), true, CHECK);
1887 instanceKlass::cast(_reference_klass)->set_reference_type(REF_OTHER);
1888 instanceRefKlass::update_nonstatic_oop_maps(_reference_klass);
1889
1890 _soft_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_SoftReference(), true, CHECK);
1891 instanceKlass::cast(_soft_reference_klass)->set_reference_type(REF_SOFT);
1892 _weak_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_WeakReference(), true, CHECK);
1893 instanceKlass::cast(_weak_reference_klass)->set_reference_type(REF_WEAK);
1894 _final_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_FinalReference(), true, CHECK);
1895 instanceKlass::cast(_final_reference_klass)->set_reference_type(REF_FINAL);
1896 _phantom_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_PhantomReference(), true, CHECK);
1897 instanceKlass::cast(_phantom_reference_klass)->set_reference_type(REF_PHANTOM);
1898 _finalizer_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Finalizer(), true, CHECK);
1899
1900 _thread_klass = resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
1901 _threadGroup_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK);
1902 _properties_klass = resolve_or_fail(vmSymbolHandles::java_util_Properties(), true, CHECK);
1903 _reflect_accessible_object_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_AccessibleObject(), true, CHECK);
1904 _reflect_field_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Field(), true, CHECK);
1905 _reflect_method_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Method(), true, CHECK);
1906 _reflect_constructor_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Constructor(), true, CHECK);
1907 // Universe::is_gte_jdk14x_version() is not set up by this point.
1908 // It's okay if these turn out to be NULL in non-1.4 JDKs.
1909 _reflect_magic_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MagicAccessorImpl(), CHECK);
1910 _reflect_method_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MethodAccessorImpl(), CHECK);
1911 _reflect_constructor_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstructorAccessorImpl(), CHECK);
1912 _reflect_delegating_classloader_klass = resolve_or_null(vmSymbolHandles::sun_reflect_DelegatingClassLoader(), CHECK);
1913 _reflect_constant_pool_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstantPool(), CHECK);
1914 _reflect_unsafe_static_field_accessor_impl_klass = resolve_or_null(vmSymbolHandles::sun_reflect_UnsafeStaticFieldAccessorImpl(), CHECK);
1915
1916 _vector_klass = resolve_or_fail(vmSymbolHandles::java_util_Vector(), true, CHECK);
1917 _hashtable_klass = resolve_or_fail(vmSymbolHandles::java_util_Hashtable(), true, CHECK);
1918 _stringBuffer_klass = resolve_or_fail(vmSymbolHandles::java_lang_StringBuffer(), true, CHECK);
1919
1920 // It's NULL in non-1.4 JDKs.
1921 _stackTraceElement_klass = resolve_or_null(vmSymbolHandles::java_lang_StackTraceElement(), CHECK);
1922
1923 // Universe::is_gte_jdk14x_version() is not set up by this point.
1924 // It's okay if this turns out to be NULL in non-1.4 JDKs.
1925 _java_nio_Buffer_klass = resolve_or_null(vmSymbolHandles::java_nio_Buffer(), CHECK);
1926
1927 // If this class isn't present, it won't be referenced.
1928 _sun_misc_AtomicLongCSImpl_klass = resolve_or_null(vmSymbolHandles::sun_misc_AtomicLongCSImpl(), CHECK);
1929 #ifdef KERNEL
1930 _sun_jkernel_DownloadManager_klass = resolve_or_null(vmSymbolHandles::sun_jkernel_DownloadManager(), CHECK);
1931 if (_sun_jkernel_DownloadManager_klass == NULL) {
1932 warning("Cannot find sun/jkernel/DownloadManager");
1933 }
1934 #endif // KERNEL
1935
1936 // Preload boxing klasses
1937 _boolean_klass = resolve_or_fail(vmSymbolHandles::java_lang_Boolean(), true, CHECK);
1938 _char_klass = resolve_or_fail(vmSymbolHandles::java_lang_Character(), true, CHECK);
1939 _float_klass = resolve_or_fail(vmSymbolHandles::java_lang_Float(), true, CHECK);
1940 _double_klass = resolve_or_fail(vmSymbolHandles::java_lang_Double(), true, CHECK);
1941 _byte_klass = resolve_or_fail(vmSymbolHandles::java_lang_Byte(), true, CHECK);
1942 _short_klass = resolve_or_fail(vmSymbolHandles::java_lang_Short(), true, CHECK);
1943 _int_klass = resolve_or_fail(vmSymbolHandles::java_lang_Integer(), true, CHECK);
1944 _long_klass = resolve_or_fail(vmSymbolHandles::java_lang_Long(), true, CHECK);
1945
1946 _box_klasses[T_BOOLEAN] = _boolean_klass;
1947 _box_klasses[T_CHAR] = _char_klass;
1948 _box_klasses[T_FLOAT] = _float_klass;
1949 _box_klasses[T_DOUBLE] = _double_klass;
1950 _box_klasses[T_BYTE] = _byte_klass;
1951 _box_klasses[T_SHORT] = _short_klass;
1952 _box_klasses[T_INT] = _int_klass;
1953 _box_klasses[T_LONG] = _long_klass;
1954 //_box_klasses[T_OBJECT] = _object_klass;
1955 //_box_klasses[T_ARRAY] = _object_klass;
1956
1957 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1958 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1959 _has_loadClassInternal = (method != NULL);
1960 }
1961
1962 { // Compute whether we should use checkPackageAccess or NOT
1963 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1964 _has_checkPackageAccess = (method != NULL);
1965 }
1966 }
1967
1968 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1969 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1970 BasicType SystemDictionary::box_klass_type(klassOop k) {
1971 assert(k != NULL, "");
1972 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1973 if (_box_klasses[i] == k)
1974 return (BasicType)i;
1975 }
1976 return T_OBJECT;
1977 }
1978
1979 // Constraints on class loaders. The details of the algorithm can be
1980 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1981 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1982 // that the system dictionary needs to maintain a set of contraints that
1983 // must be satisfied by all classes in the dictionary.
1984 // if defining is true, then LinkageError if already in systemDictionary
1985 // if initiating loader, then ok if instanceKlass matches existing entry
1986
1987 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1988 instanceKlassHandle k,
1989 Handle class_loader, bool defining,
1990 TRAPS) {
1991 const char *linkage_error = NULL;
1992 {
1993 symbolHandle name (THREAD, k->name());
1994 MutexLocker mu(SystemDictionary_lock, THREAD);
1995
1996 klassOop check = find_class(d_index, d_hash, name, class_loader);
1997 if (check != (klassOop)NULL) {
1998 // if different instanceKlass - duplicate class definition,
1999 // else - ok, class loaded by a different thread in parallel,
2000 // we should only have found it if it was done loading and ok to use
2001 // system dictionary only holds instance classes, placeholders
2002 // also holds array classes
2003
2004 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2005 if ((defining == true) || (k() != check)) {
2006 linkage_error = "loader (instance of %s): attempted duplicate class "
2007 "definition for name: \"%s\"";
2008 } else {
2009 return;
2010 }
2011 }
2012
2013 #ifdef ASSERT
2014 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
2015 int p_index = placeholders()->hash_to_index(p_hash);
2016 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2017 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
2018 #endif
2019
2020 if (linkage_error == NULL) {
2021 if (constraints()->check_or_update(k, class_loader, name) == false) {
2022 linkage_error = "loader constraint violation: loader (instance of %s)"
2023 " previously initiated loading for a different type with name \"%s\"";
2024 }
2025 }
2026 }
2027
2028 // Throw error now if needed (cannot throw while holding
2029 // SystemDictionary_lock because of rank ordering)
2030
2031 if (linkage_error) {
2032 ResourceMark rm(THREAD);
2033 const char* class_loader_name = loader_name(class_loader());
2034 char* type_name = k->name()->as_C_string();
2035 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2036 strlen(type_name);
2037 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2038 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2039 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2040 }
2041 }
2042
2043
2044 // Update system dictionary - done after check_constraint and add_to_hierachy
2045 // have been called.
2046 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2047 int p_index, unsigned int p_hash,
2048 instanceKlassHandle k,
2049 Handle class_loader,
2050 TRAPS) {
2051 // Compile_lock prevents systemDictionary updates during compilations
2052 assert_locked_or_safepoint(Compile_lock);
2053 symbolHandle name (THREAD, k->name());
2054
2055 {
2056 MutexLocker mu1(SystemDictionary_lock, THREAD);
2057
2058 // See whether biased locking is enabled and if so set it for this
2059 // klass.
2060 // Note that this must be done past the last potential blocking
2061 // point / safepoint. We enable biased locking lazily using a
2062 // VM_Operation to iterate the SystemDictionary and installing the
2063 // biasable mark word into each instanceKlass's prototype header.
2064 // To avoid race conditions where we accidentally miss enabling the
2065 // optimization for one class in the process of being added to the
2066 // dictionary, we must not safepoint after the test of
2067 // BiasedLocking::enabled().
2068 if (UseBiasedLocking && BiasedLocking::enabled()) {
2069 // Set biased locking bit for all loaded classes; it will be
2070 // cleared if revocation occurs too often for this type
2071 // NOTE that we must only do this when the class is initally
2072 // defined, not each time it is referenced from a new class loader
2073 if (k->class_loader() == class_loader()) {
2074 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2075 }
2076 }
2077
2078 // Check for a placeholder. If there, remove it and make a
2079 // new system dictionary entry.
2080 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2081 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2082 if (sd_check == NULL) {
2083 dictionary()->add_klass(name, class_loader, k);
2084 notice_modification();
2085 }
2086 #ifdef ASSERT
2087 sd_check = find_class(d_index, d_hash, name, class_loader);
2088 assert (sd_check != NULL, "should have entry in system dictionary");
2089 // Changed to allow PH to remain to complete class circularity checking
2090 // while only one thread can define a class at one time, multiple
2091 // classes can resolve the superclass for a class at one time,
2092 // and the placeholder is used to track that
2093 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2094 // assert (ph_check == NULL, "should not have a placeholder entry");
2095 #endif
2096 SystemDictionary_lock->notify_all();
2097 }
2098 }
2099
2100
2101 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2102 symbolHandle class_name, Handle class_loader, TRAPS) {
2103
2104 // First see if it has been loaded directly.
2105 // Force the protection domain to be null. (This removes protection checks.)
2106 Handle no_protection_domain;
2107 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2108 no_protection_domain, CHECK_NULL);
2109 if (klass != NULL)
2110 return klass;
2111
2112 // Now look to see if it has been loaded elsewhere, and is subject to
2113 // a loader constraint that would require this loader to return the
2114 // klass that is already loaded.
2115 if (FieldType::is_array(class_name())) {
2116 // Array classes are hard because their klassOops are not kept in the
2117 // constraint table. The array klass may be constrained, but the elem class
2118 // may not be.
2119 jint dimension;
2120 symbolOop object_key;
2121 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2122 &object_key, CHECK_(NULL));
2123 if (t != T_OBJECT) {
2124 klass = Universe::typeArrayKlassObj(t);
2125 } else {
2126 symbolHandle elem_name(THREAD, object_key);
2127 MutexLocker mu(SystemDictionary_lock, THREAD);
2128 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2129 }
2130 if (klass != NULL) {
2131 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2132 }
2133 } else {
2134 MutexLocker mu(SystemDictionary_lock, THREAD);
2135 // Non-array classes are easy: simply check the constraint table.
2136 klass = constraints()->find_constrained_klass(class_name, class_loader);
2137 }
2138
2139 return klass;
2140 }
2141
2142
2143 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2144 Handle class_loader1,
2145 Handle class_loader2,
2146 Thread* THREAD) {
2147 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2148 int d_index1 = dictionary()->hash_to_index(d_hash1);
2149
2150 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2151 int d_index2 = dictionary()->hash_to_index(d_hash2);
2152
2153 {
2154 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2155
2156 // Better never do a GC while we're holding these oops
2157 No_Safepoint_Verifier nosafepoint;
2158
2159 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2160 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2161 return constraints()->add_entry(class_name, klass1, class_loader1,
2162 klass2, class_loader2);
2163 }
2164 }
2165
2166 // Add entry to resolution error table to record the error when the first
2167 // attempt to resolve a reference to a class has failed.
2168 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2169 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2170 int index = resolution_errors()->hash_to_index(hash);
2171 {
2172 MutexLocker ml(SystemDictionary_lock, Thread::current());
2173 resolution_errors()->add_entry(index, hash, pool, which, error);
2174 }
2175 }
2176
2177 // Lookup resolution error table. Returns error if found, otherwise NULL.
2178 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2179 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2180 int index = resolution_errors()->hash_to_index(hash);
2181 {
2182 MutexLocker ml(SystemDictionary_lock, Thread::current());
2183 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2184 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2185 }
2186 }
2187
2188
2189 // Make sure all class components (including arrays) in the given
2190 // signature will be resolved to the same class in both loaders.
2191 // Returns the name of the type that failed a loader constraint check, or
2192 // NULL if no constraint failed. The returned C string needs cleaning up
2193 // with a ResourceMark in the caller
2194 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2195 Handle loader1, Handle loader2,
2196 bool is_method, TRAPS) {
2197 // Nothing to do if loaders are the same.
2198 if (loader1() == loader2()) {
2199 return NULL;
2200 }
2201
2202 SignatureStream sig_strm(signature, is_method);
2203 while (!sig_strm.is_done()) {
2204 if (sig_strm.is_object()) {
2205 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2206 symbolHandle sig (THREAD, s);
2207 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2208 return sig()->as_C_string();
2209 }
2210 }
2211 sig_strm.next();
2212 }
2213 return NULL;
2214 }
2215
2216
2217 // Since the identity hash code for symbols changes when the symbols are
2218 // moved from the regular perm gen (hash in the mark word) to the shared
2219 // spaces (hash is the address), the classes loaded into the dictionary
2220 // may be in the wrong buckets.
2221
2222 void SystemDictionary::reorder_dictionary() {
2223 dictionary()->reorder_dictionary();
2224 }
2225
2226
2227 void SystemDictionary::copy_buckets(char** top, char* end) {
2228 dictionary()->copy_buckets(top, end);
2229 }
2230
2231
2232 void SystemDictionary::copy_table(char** top, char* end) {
2233 dictionary()->copy_table(top, end);
2234 }
2235
2236
2237 void SystemDictionary::reverse() {
2238 dictionary()->reverse();
2239 }
2240
2241 int SystemDictionary::number_of_classes() {
2242 return dictionary()->number_of_entries();
2243 }
2244
2245
2246 // ----------------------------------------------------------------------------
2247 #ifndef PRODUCT
2248
2249 void SystemDictionary::print() {
2250 dictionary()->print();
2251
2252 // Placeholders
2253 GCMutexLocker mu(SystemDictionary_lock);
2254 placeholders()->print();
2255
2256 // loader constraints - print under SD_lock
2257 constraints()->print();
2258 }
2259
2260 #endif
2261
2262 void SystemDictionary::verify() {
2263 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2264 guarantee(constraints() != NULL,
2265 "Verify of loader constraints failed");
2266 guarantee(dictionary()->number_of_entries() >= 0 &&
2267 placeholders()->number_of_entries() >= 0,
2268 "Verify of system dictionary failed");
2269
2270 // Verify dictionary
2271 dictionary()->verify();
2272
2273 GCMutexLocker mu(SystemDictionary_lock);
2274 placeholders()->verify();
2275
2276 // Verify constraint table
2277 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2278 constraints()->verify(dictionary());
2279 }
2280
2281
2282 void SystemDictionary::verify_obj_klass_present(Handle obj,
2283 symbolHandle class_name,
2284 Handle class_loader) {
2285 GCMutexLocker mu(SystemDictionary_lock);
2286 oop probe = find_class_or_placeholder(class_name, class_loader);
2287 if (probe == NULL) {
2288 probe = SystemDictionary::find_shared_class(class_name);
2289 }
2290 guarantee(probe != NULL &&
2291 (!probe->is_klass() || probe == obj()),
2292 "Loaded klasses should be in SystemDictionary");
2293 }
2294
2295 #ifndef PRODUCT
2296
2297 // statistics code
2298 class ClassStatistics: AllStatic {
2299 private:
2300 static int nclasses; // number of classes
2301 static int nmethods; // number of methods
2302 static int nmethoddata; // number of methodData
2303 static int class_size; // size of class objects in words
2304 static int method_size; // size of method objects in words
2305 static int debug_size; // size of debug info in methods
2306 static int methoddata_size; // size of methodData objects in words
2307
2308 static void do_class(klassOop k) {
2309 nclasses++;
2310 class_size += k->size();
2311 if (k->klass_part()->oop_is_instance()) {
2312 instanceKlass* ik = (instanceKlass*)k->klass_part();
2313 class_size += ik->methods()->size();
2314 class_size += ik->constants()->size();
2315 class_size += ik->local_interfaces()->size();
2316 class_size += ik->transitive_interfaces()->size();
2317 // We do not have to count implementors, since we only store one!
2318 class_size += ik->fields()->size();
2319 }
2320 }
2321
2322 static void do_method(methodOop m) {
2323 nmethods++;
2324 method_size += m->size();
2325 // class loader uses same objArray for empty vectors, so don't count these
2326 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2327 if (m->has_stackmap_table()) {
2328 method_size += m->stackmap_data()->size();
2329 }
2330
2331 methodDataOop mdo = m->method_data();
2332 if (mdo != NULL) {
2333 nmethoddata++;
2334 methoddata_size += mdo->size();
2335 }
2336 }
2337
2338 public:
2339 static void print() {
2340 SystemDictionary::classes_do(do_class);
2341 SystemDictionary::methods_do(do_method);
2342 tty->print_cr("Class statistics:");
2343 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2344 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2345 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2346 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2347 }
2348 };
2349
2350
2351 int ClassStatistics::nclasses = 0;
2352 int ClassStatistics::nmethods = 0;
2353 int ClassStatistics::nmethoddata = 0;
2354 int ClassStatistics::class_size = 0;
2355 int ClassStatistics::method_size = 0;
2356 int ClassStatistics::debug_size = 0;
2357 int ClassStatistics::methoddata_size = 0;
2358
2359 void SystemDictionary::print_class_statistics() {
2360 ResourceMark rm;
2361 ClassStatistics::print();
2362 }
2363
2364
2365 class MethodStatistics: AllStatic {
2366 public:
2367 enum {
2368 max_parameter_size = 10
2369 };
2370 private:
2371
2372 static int _number_of_methods;
2373 static int _number_of_final_methods;
2374 static int _number_of_static_methods;
2375 static int _number_of_native_methods;
2376 static int _number_of_synchronized_methods;
2377 static int _number_of_profiled_methods;
2378 static int _number_of_bytecodes;
2379 static int _parameter_size_profile[max_parameter_size];
2380 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2381
2382 static void initialize() {
2383 _number_of_methods = 0;
2384 _number_of_final_methods = 0;
2385 _number_of_static_methods = 0;
2386 _number_of_native_methods = 0;
2387 _number_of_synchronized_methods = 0;
2388 _number_of_profiled_methods = 0;
2389 _number_of_bytecodes = 0;
2390 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2391 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2392 };
2393
2394 static void do_method(methodOop m) {
2395 _number_of_methods++;
2396 // collect flag info
2397 if (m->is_final() ) _number_of_final_methods++;
2398 if (m->is_static() ) _number_of_static_methods++;
2399 if (m->is_native() ) _number_of_native_methods++;
2400 if (m->is_synchronized()) _number_of_synchronized_methods++;
2401 if (m->method_data() != NULL) _number_of_profiled_methods++;
2402 // collect parameter size info (add one for receiver, if any)
2403 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2404 // collect bytecodes info
2405 {
2406 Thread *thread = Thread::current();
2407 HandleMark hm(thread);
2408 BytecodeStream s(methodHandle(thread, m));
2409 Bytecodes::Code c;
2410 while ((c = s.next()) >= 0) {
2411 _number_of_bytecodes++;
2412 _bytecodes_profile[c]++;
2413 }
2414 }
2415 }
2416
2417 public:
2418 static void print() {
2419 initialize();
2420 SystemDictionary::methods_do(do_method);
2421 // generate output
2422 tty->cr();
2423 tty->print_cr("Method statistics (static):");
2424 // flag distribution
2425 tty->cr();
2426 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2427 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2428 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2429 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2430 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2431 // parameter size profile
2432 tty->cr();
2433 { int tot = 0;
2434 int avg = 0;
2435 for (int i = 0; i < max_parameter_size; i++) {
2436 int n = _parameter_size_profile[i];
2437 tot += n;
2438 avg += n*i;
2439 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2440 }
2441 assert(tot == _number_of_methods, "should be the same");
2442 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2443 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2444 }
2445 // bytecodes profile
2446 tty->cr();
2447 { int tot = 0;
2448 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2449 if (Bytecodes::is_defined(i)) {
2450 Bytecodes::Code c = Bytecodes::cast(i);
2451 int n = _bytecodes_profile[c];
2452 tot += n;
2453 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2454 }
2455 }
2456 assert(tot == _number_of_bytecodes, "should be the same");
2457 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2458 }
2459 tty->cr();
2460 }
2461 };
2462
2463 int MethodStatistics::_number_of_methods;
2464 int MethodStatistics::_number_of_final_methods;
2465 int MethodStatistics::_number_of_static_methods;
2466 int MethodStatistics::_number_of_native_methods;
2467 int MethodStatistics::_number_of_synchronized_methods;
2468 int MethodStatistics::_number_of_profiled_methods;
2469 int MethodStatistics::_number_of_bytecodes;
2470 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2471 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2472
2473
2474 void SystemDictionary::print_method_statistics() {
2475 MethodStatistics::print();
2476 }
2477
2478 #endif // PRODUCT