1 /*
2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 # include "incls/_precompiled.incl"
26 # include "incls/_systemDictionary.cpp.incl"
27
28
29 Dictionary* SystemDictionary::_dictionary = NULL;
30 PlaceholderTable* SystemDictionary::_placeholders = NULL;
31 Dictionary* SystemDictionary::_shared_dictionary = NULL;
32 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
33 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
34
35
36 int SystemDictionary::_number_of_modifications = 0;
37
38 oop SystemDictionary::_system_loader_lock_obj = NULL;
39
40 klassOop SystemDictionary::_object_klass = NULL;
41 klassOop SystemDictionary::_string_klass = NULL;
42 klassOop SystemDictionary::_class_klass = NULL;
43 klassOop SystemDictionary::_cloneable_klass = NULL;
44 klassOop SystemDictionary::_classloader_klass = NULL;
45 klassOop SystemDictionary::_serializable_klass = NULL;
46 klassOop SystemDictionary::_system_klass = NULL;
47
48 klassOop SystemDictionary::_throwable_klass = NULL;
49 klassOop SystemDictionary::_error_klass = NULL;
50 klassOop SystemDictionary::_threaddeath_klass = NULL;
51 klassOop SystemDictionary::_exception_klass = NULL;
52 klassOop SystemDictionary::_runtime_exception_klass = NULL;
53 klassOop SystemDictionary::_classNotFoundException_klass = NULL;
54 klassOop SystemDictionary::_noClassDefFoundError_klass = NULL;
55 klassOop SystemDictionary::_linkageError_klass = NULL;
56 klassOop SystemDictionary::_classCastException_klass = NULL;
57 klassOop SystemDictionary::_arrayStoreException_klass = NULL;
58 klassOop SystemDictionary::_virtualMachineError_klass = NULL;
59 klassOop SystemDictionary::_outOfMemoryError_klass = NULL;
60 klassOop SystemDictionary::_StackOverflowError_klass = NULL;
61 klassOop SystemDictionary::_illegalMonitorStateException_klass = NULL;
62 klassOop SystemDictionary::_protectionDomain_klass = NULL;
63 klassOop SystemDictionary::_AccessControlContext_klass = NULL;
64
65 klassOop SystemDictionary::_reference_klass = NULL;
66 klassOop SystemDictionary::_soft_reference_klass = NULL;
67 klassOop SystemDictionary::_weak_reference_klass = NULL;
68 klassOop SystemDictionary::_final_reference_klass = NULL;
69 klassOop SystemDictionary::_phantom_reference_klass = NULL;
70 klassOop SystemDictionary::_finalizer_klass = NULL;
71
72 klassOop SystemDictionary::_thread_klass = NULL;
73 klassOop SystemDictionary::_threadGroup_klass = NULL;
74 klassOop SystemDictionary::_properties_klass = NULL;
75 klassOop SystemDictionary::_reflect_accessible_object_klass = NULL;
76 klassOop SystemDictionary::_reflect_field_klass = NULL;
77 klassOop SystemDictionary::_reflect_method_klass = NULL;
78 klassOop SystemDictionary::_reflect_constructor_klass = NULL;
79 klassOop SystemDictionary::_reflect_magic_klass = NULL;
80 klassOop SystemDictionary::_reflect_method_accessor_klass = NULL;
81 klassOop SystemDictionary::_reflect_constructor_accessor_klass = NULL;
82 klassOop SystemDictionary::_reflect_delegating_classloader_klass = NULL;
83 klassOop SystemDictionary::_reflect_constant_pool_klass = NULL;
84 klassOop SystemDictionary::_reflect_unsafe_static_field_accessor_impl_klass = NULL;
85
86 klassOop SystemDictionary::_vector_klass = NULL;
87 klassOop SystemDictionary::_hashtable_klass = NULL;
88 klassOop SystemDictionary::_stringBuffer_klass = NULL;
89
90 klassOop SystemDictionary::_stackTraceElement_klass = NULL;
91
92 klassOop SystemDictionary::_java_nio_Buffer_klass = NULL;
93
94 klassOop SystemDictionary::_sun_misc_AtomicLongCSImpl_klass = NULL;
95 klassOop SystemDictionary::_sun_jkernel_DownloadManager_klass = NULL;
96
97 klassOop SystemDictionary::_boolean_klass = NULL;
98 klassOop SystemDictionary::_char_klass = NULL;
99 klassOop SystemDictionary::_float_klass = NULL;
100 klassOop SystemDictionary::_double_klass = NULL;
101 klassOop SystemDictionary::_byte_klass = NULL;
102 klassOop SystemDictionary::_short_klass = NULL;
103 klassOop SystemDictionary::_int_klass = NULL;
104 klassOop SystemDictionary::_long_klass = NULL;
105 klassOop SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108
109 bool SystemDictionary::_has_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 volatile klassOop SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115
116 // ----------------------------------------------------------------------------
117 // Java-level SystemLoader
118
119 oop SystemDictionary::java_system_loader() {
120 return _java_system_loader;
121 }
122
123 void SystemDictionary::compute_java_system_loader(TRAPS) {
124 KlassHandle system_klass(THREAD, _classloader_klass);
125 JavaValue result(T_OBJECT);
126 JavaCalls::call_static(&result,
127 KlassHandle(THREAD, _classloader_klass),
128 vmSymbolHandles::getSystemClassLoader_name(),
129 vmSymbolHandles::void_classloader_signature(),
130 CHECK);
131
132 _java_system_loader = (oop)result.get_jobject();
133 }
134
135
136 // ----------------------------------------------------------------------------
137 // debugging
138
139 #ifdef ASSERT
140
141 // return true if class_name contains no '.' (internal format is '/')
142 bool SystemDictionary::is_internal_format(symbolHandle class_name) {
143 if (class_name.not_null()) {
144 ResourceMark rm;
145 char* name = class_name->as_C_string();
146 return strchr(name, '.') == NULL;
147 } else {
148 return true;
149 }
150 }
151
152 #endif
153
154 // ----------------------------------------------------------------------------
155 // Resolving of classes
156
157 // Forwards to resolve_or_null
158
159 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
160 klassOop klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
161 if (HAS_PENDING_EXCEPTION || klass == NULL) {
162 KlassHandle k_h(THREAD, klass);
163 // can return a null klass
164 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
165 }
166 return klass;
167 }
168
169 klassOop SystemDictionary::handle_resolution_exception(symbolHandle class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
170 if (HAS_PENDING_EXCEPTION) {
171 // If we have a pending exception we forward it to the caller, unless throw_error is true,
172 // in which case we have to check whether the pending exception is a ClassNotFoundException,
173 // and if so convert it to a NoClassDefFoundError
174 // And chain the original ClassNotFoundException
175 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::classNotFoundException_klass())) {
176 ResourceMark rm(THREAD);
177 assert(klass_h() == NULL, "Should not have result with exception pending");
178 Handle e(THREAD, PENDING_EXCEPTION);
179 CLEAR_PENDING_EXCEPTION;
180 THROW_MSG_CAUSE_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
181 } else {
182 return NULL;
183 }
184 }
185 // Class not found, throw appropriate error or exception depending on value of throw_error
186 if (klass_h() == NULL) {
187 ResourceMark rm(THREAD);
188 if (throw_error) {
189 THROW_MSG_0(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
190 } else {
191 THROW_MSG_0(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
192 }
193 }
194 return (klassOop)klass_h();
195 }
196
197
198 klassOop SystemDictionary::resolve_or_fail(symbolHandle class_name,
199 bool throw_error, TRAPS)
200 {
201 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
202 }
203
204
205 // Forwards to resolve_instance_class_or_null
206
207 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
208 assert(!THREAD->is_Compiler_thread(), "Can not load classes with the Compiler thread");
209 if (FieldType::is_array(class_name())) {
210 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
211 } else {
212 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
213 }
214 }
215
216 klassOop SystemDictionary::resolve_or_null(symbolHandle class_name, TRAPS) {
217 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
218 }
219
220 // Forwards to resolve_instance_class_or_null
221
222 klassOop SystemDictionary::resolve_array_class_or_null(symbolHandle class_name,
223 Handle class_loader,
224 Handle protection_domain,
225 TRAPS) {
226 assert(FieldType::is_array(class_name()), "must be array");
227 jint dimension;
228 symbolOop object_key;
229 klassOop k = NULL;
230 // dimension and object_key are assigned as a side-effect of this call
231 BasicType t = FieldType::get_array_info(class_name(),
232 &dimension,
233 &object_key,
234 CHECK_NULL);
235
236 if (t == T_OBJECT) {
237 symbolHandle h_key(THREAD, object_key);
238 // naked oop "k" is OK here -- we assign back into it
239 k = SystemDictionary::resolve_instance_class_or_null(h_key,
240 class_loader,
241 protection_domain,
242 CHECK_NULL);
243 if (k != NULL) {
244 k = Klass::cast(k)->array_klass(dimension, CHECK_NULL);
245 }
246 } else {
247 k = Universe::typeArrayKlassObj(t);
248 k = typeArrayKlass::cast(k)->array_klass(dimension, CHECK_NULL);
249 }
250 return k;
251 }
252
253
254 // Must be called for any super-class or super-interface resolution
255 // during class definition to allow class circularity checking
256 // super-interface callers:
257 // parse_interfaces - for defineClass & jvmtiRedefineClasses
258 // super-class callers:
259 // ClassFileParser - for defineClass & jvmtiRedefineClasses
260 // load_shared_class - while loading a class from shared archive
261 // resolve_instance_class_or_fail:
262 // when resolving a class that has an existing placeholder with
263 // a saved superclass [i.e. a defineClass is currently in progress]
264 // if another thread is trying to resolve the class, it must do
265 // super-class checks on its own thread to catch class circularity
266 // This last call is critical in class circularity checking for cases
267 // where classloading is delegated to different threads and the
268 // classloader lock is released.
269 // Take the case: Base->Super->Base
270 // 1. If thread T1 tries to do a defineClass of class Base
271 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
272 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
273 // so it tries to load Super
274 // 3. If we load the class internally, or user classloader uses same thread
275 // loadClassFromxxx or defineClass via parseClassFile Super ...
276 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
277 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
278 // 3.4 calls resolve_super_or_fail Base
279 // 3.5 finds T1,Base -> throws class circularity
280 //OR 4. If T2 tries to resolve Super via defineClass Super ...
281 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
282 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
283 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
284 // 4.4 finds T2, Super -> throws class circularity
285 // Must be called, even if superclass is null, since this is
286 // where the placeholder entry is created which claims this
287 // thread is loading this class/classloader.
288 klassOop SystemDictionary::resolve_super_or_fail(symbolHandle child_name,
289 symbolHandle class_name,
290 Handle class_loader,
291 Handle protection_domain,
292 bool is_superclass,
293 TRAPS) {
294
295 // Double-check, if child class is already loaded, just return super-class,interface
296 // Don't add a placedholder if already loaded, i.e. already in system dictionary
297 // Make sure there's a placeholder for the *child* before resolving.
298 // Used as a claim that this thread is currently loading superclass/classloader
299 // Used here for ClassCircularity checks and also for heap verification
300 // (every instanceKlass in the heap needs to be in the system dictionary
301 // or have a placeholder).
302 // Must check ClassCircularity before checking if super class is already loaded
303 //
304 // We might not already have a placeholder if this child_name was
305 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
306 // the name of the class might not be known until the stream is actually
307 // parsed.
308 // Bugs 4643874, 4715493
309 // compute_hash can have a safepoint
310
311 unsigned int d_hash = dictionary()->compute_hash(child_name, class_loader);
312 int d_index = dictionary()->hash_to_index(d_hash);
313 unsigned int p_hash = placeholders()->compute_hash(child_name, class_loader);
314 int p_index = placeholders()->hash_to_index(p_hash);
315 // can't throw error holding a lock
316 bool child_already_loaded = false;
317 bool throw_circularity_error = false;
318 {
319 MutexLocker mu(SystemDictionary_lock, THREAD);
320 klassOop childk = find_class(d_index, d_hash, child_name, class_loader);
321 klassOop quicksuperk;
322 // to support // loading: if child done loading, just return superclass
323 // if class_name, & class_loader don't match:
324 // if initial define, SD update will give LinkageError
325 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
326 // so we don't throw an exception here.
327 // see: nsk redefclass014 & java.lang.instrument Instrument032
328 if ((childk != NULL ) && (is_superclass) &&
329 ((quicksuperk = instanceKlass::cast(childk)->super()) != NULL) &&
330
331 ((Klass::cast(quicksuperk)->name() == class_name()) &&
332 (Klass::cast(quicksuperk)->class_loader() == class_loader()))) {
333 return quicksuperk;
334 } else {
335 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
336 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
337 throw_circularity_error = true;
338 }
339
340 // add placeholder entry even if error - callers will remove on error
341 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, class_loader, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
342 if (throw_circularity_error) {
343 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
344 }
345 }
346 }
347 if (throw_circularity_error) {
348 ResourceMark rm(THREAD);
349 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
350 }
351
352 // java.lang.Object should have been found above
353 assert(class_name() != NULL, "null super class for resolving");
354 // Resolve the super class or interface, check results on return
355 klassOop superk = NULL;
356 superk = SystemDictionary::resolve_or_null(class_name,
357 class_loader,
358 protection_domain,
359 THREAD);
360
361 KlassHandle superk_h(THREAD, superk);
362
363 // Note: clean up of placeholders currently in callers of
364 // resolve_super_or_fail - either at update_dictionary time
365 // or on error
366 {
367 MutexLocker mu(SystemDictionary_lock, THREAD);
368 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, class_loader);
369 if (probe != NULL) {
370 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER);
371 }
372 }
373 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
374 // can null superk
375 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
376 }
377
378 return superk_h();
379 }
380
381
382 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
383 Handle class_loader,
384 Handle protection_domain,
385 TRAPS) {
386 if(!has_checkPackageAccess()) return;
387
388 // Now we have to call back to java to check if the initating class has access
389 JavaValue result(T_VOID);
390 if (TraceProtectionDomainVerification) {
391 // Print out trace information
392 tty->print_cr("Checking package access");
393 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
394 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
395 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
396 }
397
398 assert(class_loader() != NULL, "should not have non-null protection domain for null classloader");
399
400 KlassHandle system_loader(THREAD, SystemDictionary::classloader_klass());
401 JavaCalls::call_special(&result,
402 class_loader,
403 system_loader,
404 vmSymbolHandles::checkPackageAccess_name(),
405 vmSymbolHandles::class_protectiondomain_signature(),
406 Handle(THREAD, klass->java_mirror()),
407 protection_domain,
408 THREAD);
409
410 if (TraceProtectionDomainVerification) {
411 if (HAS_PENDING_EXCEPTION) {
412 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
413 } else {
414 tty->print_cr(" -> granted");
415 }
416 tty->cr();
417 }
418
419 if (HAS_PENDING_EXCEPTION) return;
420
421 // If no exception has been thrown, we have validated the protection domain
422 // Insert the protection domain of the initiating class into the set.
423 {
424 // We recalculate the entry here -- we've called out to java since
425 // the last time it was calculated.
426 symbolHandle kn(THREAD, klass->name());
427 unsigned int d_hash = dictionary()->compute_hash(kn, class_loader);
428 int d_index = dictionary()->hash_to_index(d_hash);
429
430 MutexLocker mu(SystemDictionary_lock, THREAD);
431 {
432 // Note that we have an entry, and entries can be deleted only during GC,
433 // so we cannot allow GC to occur while we're holding this entry.
434
435 // We're using a No_Safepoint_Verifier to catch any place where we
436 // might potentially do a GC at all.
437 // SystemDictionary::do_unloading() asserts that classes are only
438 // unloaded at a safepoint.
439 No_Safepoint_Verifier nosafepoint;
440 dictionary()->add_protection_domain(d_index, d_hash, klass, class_loader,
441 protection_domain, THREAD);
442 }
443 }
444 }
445
446 // We only get here if this thread finds that another thread
447 // has already claimed the placeholder token for the current operation,
448 // but that other thread either never owned or gave up the
449 // object lock
450 // Waits on SystemDictionary_lock to indicate placeholder table updated
451 // On return, caller must recheck placeholder table state
452 //
453 // We only get here if
454 // 1) custom classLoader, i.e. not bootstrap classloader
455 // 2) UnsyncloadClass not set
456 // 3) custom classLoader has broken the class loader objectLock
457 // so another thread got here in parallel
458 //
459 // lockObject must be held.
460 // Complicated dance due to lock ordering:
461 // Must first release the classloader object lock to
462 // allow initial definer to complete the class definition
463 // and to avoid deadlock
464 // Reclaim classloader lock object with same original recursion count
465 // Must release SystemDictionary_lock after notify, since
466 // class loader lock must be claimed before SystemDictionary_lock
467 // to prevent deadlocks
468 //
469 // The notify allows applications that did an untimed wait() on
470 // the classloader object lock to not hang.
471 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
472 assert_lock_strong(SystemDictionary_lock);
473
474 bool calledholdinglock
475 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
476 assert(calledholdinglock,"must hold lock for notify");
477 assert(!UnsyncloadClass, "unexpected double_lock_wait");
478 ObjectSynchronizer::notifyall(lockObject, THREAD);
479 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
480 SystemDictionary_lock->wait();
481 SystemDictionary_lock->unlock();
482 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
483 SystemDictionary_lock->lock();
484 }
485
486 // If the class in is in the placeholder table, class loading is in progress
487 // For cases where the application changes threads to load classes, it
488 // is critical to ClassCircularity detection that we try loading
489 // the superclass on the same thread internally, so we do parallel
490 // super class loading here.
491 // This also is critical in cases where the original thread gets stalled
492 // even in non-circularity situations.
493 // Note: only one thread can define the class, but multiple can resolve
494 // Note: must call resolve_super_or_fail even if null super -
495 // to force placeholder entry creation for this class
496 // Caller must check for pending exception
497 // Returns non-null klassOop if other thread has completed load
498 // and we are done,
499 // If return null klassOop and no pending exception, the caller must load the class
500 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
501 symbolHandle name, symbolHandle superclassname, Handle class_loader,
502 Handle protection_domain, Handle lockObject, TRAPS) {
503
504 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
505 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
506 int d_index = dictionary()->hash_to_index(d_hash);
507 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
508 int p_index = placeholders()->hash_to_index(p_hash);
509
510 // superk is not used, resolve_super called for circularity check only
511 // This code is reached in two situations. One if this thread
512 // is loading the same class twice (e.g. ClassCircularity, or
513 // java.lang.instrument).
514 // The second is if another thread started the resolve_super first
515 // and has not yet finished.
516 // In both cases the original caller will clean up the placeholder
517 // entry on error.
518 klassOop superk = SystemDictionary::resolve_super_or_fail(name,
519 superclassname,
520 class_loader,
521 protection_domain,
522 true,
523 CHECK_(nh));
524 // We don't redefine the class, so we just need to clean up if there
525 // was not an error (don't want to modify any system dictionary
526 // data structures).
527 {
528 MutexLocker mu(SystemDictionary_lock, THREAD);
529 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
530 SystemDictionary_lock->notify_all();
531 }
532
533 // UnsyncloadClass does NOT wait for parallel superclass loads to complete
534 // Bootstrap classloader does wait for parallel superclass loads
535 if (UnsyncloadClass) {
536 MutexLocker mu(SystemDictionary_lock, THREAD);
537 // Check if classloading completed while we were loading superclass or waiting
538 klassOop check = find_class(d_index, d_hash, name, class_loader);
539 if (check != NULL) {
540 // Klass is already loaded, so just return it
541 return(instanceKlassHandle(THREAD, check));
542 } else {
543 return nh;
544 }
545 }
546
547 // must loop to both handle other placeholder updates
548 // and spurious notifications
549 bool super_load_in_progress = true;
550 PlaceholderEntry* placeholder;
551 while (super_load_in_progress) {
552 MutexLocker mu(SystemDictionary_lock, THREAD);
553 // Check if classloading completed while we were loading superclass or waiting
554 klassOop check = find_class(d_index, d_hash, name, class_loader);
555 if (check != NULL) {
556 // Klass is already loaded, so just return it
557 return(instanceKlassHandle(THREAD, check));
558 } else {
559 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
560 if (placeholder && placeholder->super_load_in_progress() ){
561 // Before UnsyncloadClass:
562 // We only get here if the application has released the
563 // classloader lock when another thread was in the middle of loading a
564 // superclass/superinterface for this class, and now
565 // this thread is also trying to load this class.
566 // To minimize surprises, the first thread that started to
567 // load a class should be the one to complete the loading
568 // with the classfile it initially expected.
569 // This logic has the current thread wait once it has done
570 // all the superclass/superinterface loading it can, until
571 // the original thread completes the class loading or fails
572 // If it completes we will use the resulting instanceKlass
573 // which we will find below in the systemDictionary.
574 // We also get here for parallel bootstrap classloader
575 if (class_loader.is_null()) {
576 SystemDictionary_lock->wait();
577 } else {
578 double_lock_wait(lockObject, THREAD);
579 }
580 } else {
581 // If not in SD and not in PH, other thread's load must have failed
582 super_load_in_progress = false;
583 }
584 }
585 }
586 return (nh);
587 }
588
589
590 klassOop SystemDictionary::resolve_instance_class_or_null(symbolHandle class_name, Handle class_loader, Handle protection_domain, TRAPS) {
591 assert(class_name.not_null() && !FieldType::is_array(class_name()), "invalid class name");
592 // First check to see if we should remove wrapping L and ;
593 symbolHandle name;
594 if (FieldType::is_obj(class_name())) {
595 ResourceMark rm(THREAD);
596 // Ignore wrapping L and ;.
597 name = oopFactory::new_symbol_handle(class_name()->as_C_string() + 1, class_name()->utf8_length() - 2, CHECK_NULL);
598 } else {
599 name = class_name;
600 }
601
602 // UseNewReflection
603 // Fix for 4474172; see evaluation for more details
604 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
605
606 // Do lookup to see if class already exist and the protection domain
607 // has the right access
608 unsigned int d_hash = dictionary()->compute_hash(name, class_loader);
609 int d_index = dictionary()->hash_to_index(d_hash);
610 klassOop probe = dictionary()->find(d_index, d_hash, name, class_loader,
611 protection_domain, THREAD);
612 if (probe != NULL) return probe;
613
614
615 // Non-bootstrap class loaders will call out to class loader and
616 // define via jvm/jni_DefineClass which will acquire the
617 // class loader object lock to protect against multiple threads
618 // defining the class in parallel by accident.
619 // This lock must be acquired here so the waiter will find
620 // any successful result in the SystemDictionary and not attempt
621 // the define
622 // Classloaders that support parallelism, e.g. bootstrap classloader,
623 // or all classloaders with UnsyncloadClass do not acquire lock here
624 bool DoObjectLock = true;
625 if (UnsyncloadClass || (class_loader.is_null())) {
626 DoObjectLock = false;
627 }
628
629 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
630 int p_index = placeholders()->hash_to_index(p_hash);
631
632 // Class is not in SystemDictionary so we have to do loading.
633 // Make sure we are synchronized on the class loader before we proceed
634 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
635 check_loader_lock_contention(lockObject, THREAD);
636 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
637
638 // Check again (after locking) if class already exist in SystemDictionary
639 bool class_has_been_loaded = false;
640 bool super_load_in_progress = false;
641 bool havesupername = false;
642 instanceKlassHandle k;
643 PlaceholderEntry* placeholder;
644 symbolHandle superclassname;
645
646 {
647 MutexLocker mu(SystemDictionary_lock, THREAD);
648 klassOop check = find_class(d_index, d_hash, name, class_loader);
649 if (check != NULL) {
650 // Klass is already loaded, so just return it
651 class_has_been_loaded = true;
652 k = instanceKlassHandle(THREAD, check);
653 } else {
654 placeholder = placeholders()->get_entry(p_index, p_hash, name, class_loader);
655 if (placeholder && placeholder->super_load_in_progress()) {
656 super_load_in_progress = true;
657 if (placeholder->havesupername() == true) {
658 superclassname = symbolHandle(THREAD, placeholder->supername());
659 havesupername = true;
660 }
661 }
662 }
663 }
664
665 // If the class in is in the placeholder table, class loading is in progress
666 if (super_load_in_progress && havesupername==true) {
667 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
668 class_loader, protection_domain, lockObject, THREAD);
669 if (HAS_PENDING_EXCEPTION) {
670 return NULL;
671 }
672 if (!k.is_null()) {
673 class_has_been_loaded = true;
674 }
675 }
676
677 if (!class_has_been_loaded) {
678
679 // add placeholder entry to record loading instance class
680 // Five cases:
681 // All cases need to prevent modifying bootclasssearchpath
682 // in parallel with a classload of same classname
683 // case 1. traditional classloaders that rely on the classloader object lock
684 // - no other need for LOAD_INSTANCE
685 // case 2. traditional classloaders that break the classloader object lock
686 // as a deadlock workaround. Detection of this case requires that
687 // this check is done while holding the classloader object lock,
688 // and that lock is still held when calling classloader's loadClass.
689 // For these classloaders, we ensure that the first requestor
690 // completes the load and other requestors wait for completion.
691 // case 3. UnsyncloadClass - don't use objectLocker
692 // With this flag, we allow parallel classloading of a
693 // class/classloader pair
694 // case4. Bootstrap classloader - don't own objectLocker
695 // This classloader supports parallelism at the classloader level,
696 // but only allows a single load of a class/classloader pair.
697 // No performance benefit and no deadlock issues.
698 // case 5. Future: parallel user level classloaders - without objectLocker
699 symbolHandle nullsymbolHandle;
700 bool throw_circularity_error = false;
701 {
702 MutexLocker mu(SystemDictionary_lock, THREAD);
703 if (!UnsyncloadClass) {
704 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
705 if (oldprobe) {
706 // only need check_seen_thread once, not on each loop
707 // 6341374 java/lang/Instrument with -Xcomp
708 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
709 throw_circularity_error = true;
710 } else {
711 // case 1: traditional: should never see load_in_progress.
712 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
713
714 // case 4: bootstrap classloader: prevent futile classloading,
715 // wait on first requestor
716 if (class_loader.is_null()) {
717 SystemDictionary_lock->wait();
718 } else {
719 // case 2: traditional with broken classloader lock. wait on first
720 // requestor.
721 double_lock_wait(lockObject, THREAD);
722 }
723 // Check if classloading completed while we were waiting
724 klassOop check = find_class(d_index, d_hash, name, class_loader);
725 if (check != NULL) {
726 // Klass is already loaded, so just return it
727 k = instanceKlassHandle(THREAD, check);
728 class_has_been_loaded = true;
729 }
730 // check if other thread failed to load and cleaned up
731 oldprobe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
732 }
733 }
734 }
735 }
736 // All cases: add LOAD_INSTANCE
737 // case 3: UnsyncloadClass: allow competing threads to try
738 // LOAD_INSTANCE in parallel
739 // add placeholder entry even if error - callers will remove on error
740 if (!class_has_been_loaded) {
741 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, class_loader, PlaceholderTable::LOAD_INSTANCE, nullsymbolHandle, THREAD);
742 if (throw_circularity_error) {
743 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
744 }
745 // For class loaders that do not acquire the classloader object lock,
746 // if they did not catch another thread holding LOAD_INSTANCE,
747 // need a check analogous to the acquire ObjectLocker/find_class
748 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
749 // one final check if the load has already completed
750 klassOop check = find_class(d_index, d_hash, name, class_loader);
751 if (check != NULL) {
752 // Klass is already loaded, so just return it
753 k = instanceKlassHandle(THREAD, check);
754 class_has_been_loaded = true;
755 newprobe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
756 }
757 }
758 }
759 // must throw error outside of owning lock
760 if (throw_circularity_error) {
761 ResourceMark rm(THREAD);
762 THROW_MSG_0(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
763 }
764
765 if (!class_has_been_loaded) {
766
767 // Do actual loading
768 k = load_instance_class(name, class_loader, THREAD);
769
770 // In custom class loaders, the usual findClass calls
771 // findLoadedClass, which directly searches the SystemDictionary, then
772 // defineClass. If these are not atomic with respect to other threads,
773 // the findLoadedClass can fail, but the defineClass can get a
774 // LinkageError:: duplicate class definition.
775 // If they got a linkageError, check if a parallel class load succeeded.
776 // If it did, then for bytecode resolution the specification requires
777 // that we return the same result we did for the other thread, i.e. the
778 // successfully loaded instanceKlass
779 // Note: Class can not be unloaded as long as any classloader refs exist
780 // Should not get here for classloaders that support parallelism
781 // with the new cleaner mechanism, e.g. bootstrap classloader
782 if (UnsyncloadClass || (class_loader.is_null())) {
783 if (k.is_null() && HAS_PENDING_EXCEPTION
784 && PENDING_EXCEPTION->is_a(SystemDictionary::linkageError_klass())) {
785 MutexLocker mu(SystemDictionary_lock, THREAD);
786 klassOop check = find_class(d_index, d_hash, name, class_loader);
787 if (check != NULL) {
788 // Klass is already loaded, so just use it
789 k = instanceKlassHandle(THREAD, check);
790 CLEAR_PENDING_EXCEPTION;
791 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
792 }
793 }
794 }
795
796 // clean up placeholder entries for success or error
797 // This cleans up LOAD_INSTANCE entries
798 // It also cleans up LOAD_SUPER entries on errors from
799 // calling load_instance_class
800 {
801 MutexLocker mu(SystemDictionary_lock, THREAD);
802 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name, class_loader);
803 if (probe != NULL) {
804 probe->remove_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE);
805 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
806 SystemDictionary_lock->notify_all();
807 }
808 }
809
810 // If everything was OK (no exceptions, no null return value), and
811 // class_loader is NOT the defining loader, do a little more bookkeeping.
812 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
813 k->class_loader() != class_loader()) {
814
815 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
816
817 // Need to check for a PENDING_EXCEPTION again; check_constraints
818 // can throw and doesn't use the CHECK macro.
819 if (!HAS_PENDING_EXCEPTION) {
820 { // Grabbing the Compile_lock prevents systemDictionary updates
821 // during compilations.
822 MutexLocker mu(Compile_lock, THREAD);
823 update_dictionary(d_index, d_hash, p_index, p_hash,
824 k, class_loader, THREAD);
825 }
826 if (JvmtiExport::should_post_class_load()) {
827 Thread *thread = THREAD;
828 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
829 JvmtiExport::post_class_load((JavaThread *) thread, k());
830 }
831 }
832 }
833 if (HAS_PENDING_EXCEPTION || k.is_null()) {
834 // On error, clean up placeholders
835 {
836 MutexLocker mu(SystemDictionary_lock, THREAD);
837 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
838 SystemDictionary_lock->notify_all();
839 }
840 return NULL;
841 }
842 }
843 }
844
845 #ifdef ASSERT
846 {
847 Handle loader (THREAD, k->class_loader());
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 oop kk = find_class_or_placeholder(name, loader);
850 assert(kk == k(), "should be present in dictionary");
851 }
852 #endif
853
854 // return if the protection domain in NULL
855 if (protection_domain() == NULL) return k();
856
857 // Check the protection domain has the right access
858 {
859 MutexLocker mu(SystemDictionary_lock, THREAD);
860 // Note that we have an entry, and entries can be deleted only during GC,
861 // so we cannot allow GC to occur while we're holding this entry.
862 // We're using a No_Safepoint_Verifier to catch any place where we
863 // might potentially do a GC at all.
864 // SystemDictionary::do_unloading() asserts that classes are only
865 // unloaded at a safepoint.
866 No_Safepoint_Verifier nosafepoint;
867 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
868 class_loader,
869 protection_domain)) {
870 return k();
871 }
872 }
873
874 // Verify protection domain. If it fails an exception is thrown
875 validate_protection_domain(k, class_loader, protection_domain, CHECK_(klassOop(NULL)));
876
877 return k();
878 }
879
880
881 // This routine does not lock the system dictionary.
882 //
883 // Since readers don't hold a lock, we must make sure that system
884 // dictionary entries are only removed at a safepoint (when only one
885 // thread is running), and are added to in a safe way (all links must
886 // be updated in an MT-safe manner).
887 //
888 // Callers should be aware that an entry could be added just after
889 // _dictionary->bucket(index) is read here, so the caller will not see
890 // the new entry.
891
892 klassOop SystemDictionary::find(symbolHandle class_name,
893 Handle class_loader,
894 Handle protection_domain,
895 TRAPS) {
896
897 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
898 int d_index = dictionary()->hash_to_index(d_hash);
899
900 {
901 // Note that we have an entry, and entries can be deleted only during GC,
902 // so we cannot allow GC to occur while we're holding this entry.
903 // We're using a No_Safepoint_Verifier to catch any place where we
904 // might potentially do a GC at all.
905 // SystemDictionary::do_unloading() asserts that classes are only
906 // unloaded at a safepoint.
907 No_Safepoint_Verifier nosafepoint;
908 return dictionary()->find(d_index, d_hash, class_name, class_loader,
909 protection_domain, THREAD);
910 }
911 }
912
913
914 // Look for a loaded instance or array klass by name. Do not do any loading.
915 // return NULL in case of error.
916 klassOop SystemDictionary::find_instance_or_array_klass(symbolHandle class_name,
917 Handle class_loader,
918 Handle protection_domain,
919 TRAPS) {
920 klassOop k = NULL;
921 assert(class_name() != NULL, "class name must be non NULL");
922 if (FieldType::is_array(class_name())) {
923 // The name refers to an array. Parse the name.
924 jint dimension;
925 symbolOop object_key;
926
927 // dimension and object_key are assigned as a side-effect of this call
928 BasicType t = FieldType::get_array_info(class_name(), &dimension,
929 &object_key, CHECK_(NULL));
930 if (t != T_OBJECT) {
931 k = Universe::typeArrayKlassObj(t);
932 } else {
933 symbolHandle h_key(THREAD, object_key);
934 k = SystemDictionary::find(h_key, class_loader, protection_domain, THREAD);
935 }
936 if (k != NULL) {
937 k = Klass::cast(k)->array_klass_or_null(dimension);
938 }
939 } else {
940 k = find(class_name, class_loader, protection_domain, THREAD);
941 }
942 return k;
943 }
944
945 // Note: this method is much like resolve_from_stream, but
946 // updates no supplemental data structures.
947 // TODO consolidate the two methods with a helper routine?
948 klassOop SystemDictionary::parse_stream(symbolHandle class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 ClassFileStream* st,
952 TRAPS) {
953 symbolHandle parsed_name;
954
955 // Parse the stream. Note that we do this even though this klass might
956 // already be present in the SystemDictionary, otherwise we would not
957 // throw potential ClassFormatErrors.
958 //
959 // Note: "name" is updated.
960 // Further note: a placeholder will be added for this class when
961 // super classes are loaded (resolve_super_or_fail). We expect this
962 // to be called for all classes but java.lang.Object; and we preload
963 // java.lang.Object through resolve_or_fail, not this path.
964
965 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
966 class_loader,
967 protection_domain,
968 parsed_name,
969 THREAD);
970
971
972 // We don't redefine the class, so we just need to clean up whether there
973 // was an error or not (don't want to modify any system dictionary
974 // data structures).
975 // Parsed name could be null if we threw an error before we got far
976 // enough along to parse it -- in that case, there is nothing to clean up.
977 if (!parsed_name.is_null()) {
978 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
979 class_loader);
980 int p_index = placeholders()->hash_to_index(p_hash);
981 {
982 MutexLocker mu(SystemDictionary_lock, THREAD);
983 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
984 SystemDictionary_lock->notify_all();
985 }
986 }
987
988 return k();
989 }
990
991 // Add a klass to the system from a stream (called by jni_DefineClass and
992 // JVM_DefineClass).
993 // Note: class_name can be NULL. In that case we do not know the name of
994 // the class until we have parsed the stream.
995
996 klassOop SystemDictionary::resolve_from_stream(symbolHandle class_name,
997 Handle class_loader,
998 Handle protection_domain,
999 ClassFileStream* st,
1000 TRAPS) {
1001
1002 // Make sure we are synchronized on the class loader before we initiate
1003 // loading.
1004 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1005 check_loader_lock_contention(lockObject, THREAD);
1006 ObjectLocker ol(lockObject, THREAD);
1007
1008 symbolHandle parsed_name;
1009
1010 // Parse the stream. Note that we do this even though this klass might
1011 // already be present in the SystemDictionary, otherwise we would not
1012 // throw potential ClassFormatErrors.
1013 //
1014 // Note: "name" is updated.
1015 // Further note: a placeholder will be added for this class when
1016 // super classes are loaded (resolve_super_or_fail). We expect this
1017 // to be called for all classes but java.lang.Object; and we preload
1018 // java.lang.Object through resolve_or_fail, not this path.
1019
1020 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1021 class_loader,
1022 protection_domain,
1023 parsed_name,
1024 THREAD);
1025
1026 const char* pkg = "java/";
1027 if (!HAS_PENDING_EXCEPTION &&
1028 !class_loader.is_null() &&
1029 !parsed_name.is_null() &&
1030 !strncmp((const char*)parsed_name->bytes(), pkg, strlen(pkg))) {
1031 // It is illegal to define classes in the "java." package from
1032 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1033 ResourceMark rm(THREAD);
1034 char* name = parsed_name->as_C_string();
1035 char* index = strrchr(name, '/');
1036 *index = '\0'; // chop to just the package name
1037 while ((index = strchr(name, '/')) != NULL) {
1038 *index = '.'; // replace '/' with '.' in package name
1039 }
1040 const char* fmt = "Prohibited package name: %s";
1041 size_t len = strlen(fmt) + strlen(name);
1042 char* message = NEW_RESOURCE_ARRAY(char, len);
1043 jio_snprintf(message, len, fmt, name);
1044 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1045 vmSymbols::java_lang_SecurityException(), message);
1046 }
1047
1048 if (!HAS_PENDING_EXCEPTION) {
1049 assert(!parsed_name.is_null(), "Sanity");
1050 assert(class_name.is_null() || class_name() == parsed_name(),
1051 "name mismatch");
1052 // Verification prevents us from creating names with dots in them, this
1053 // asserts that that's the case.
1054 assert(is_internal_format(parsed_name),
1055 "external class name format used internally");
1056
1057 // Add class just loaded
1058 define_instance_class(k, THREAD);
1059 }
1060
1061 // If parsing the class file or define_instance_class failed, we
1062 // need to remove the placeholder added on our behalf. But we
1063 // must make sure parsed_name is valid first (it won't be if we had
1064 // a format error before the class was parsed far enough to
1065 // find the name).
1066 if (HAS_PENDING_EXCEPTION && !parsed_name.is_null()) {
1067 unsigned int p_hash = placeholders()->compute_hash(parsed_name,
1068 class_loader);
1069 int p_index = placeholders()->hash_to_index(p_hash);
1070 {
1071 MutexLocker mu(SystemDictionary_lock, THREAD);
1072 placeholders()->find_and_remove(p_index, p_hash, parsed_name, class_loader, THREAD);
1073 SystemDictionary_lock->notify_all();
1074 }
1075 return NULL;
1076 }
1077
1078 // Make sure that we didn't leave a place holder in the
1079 // SystemDictionary; this is only done on success
1080 debug_only( {
1081 if (!HAS_PENDING_EXCEPTION) {
1082 assert(!parsed_name.is_null(), "parsed_name is still null?");
1083 symbolHandle h_name (THREAD, k->name());
1084 Handle h_loader (THREAD, k->class_loader());
1085
1086 MutexLocker mu(SystemDictionary_lock, THREAD);
1087
1088 oop check = find_class_or_placeholder(parsed_name, class_loader);
1089 assert(check == k(), "should be present in the dictionary");
1090
1091 oop check2 = find_class_or_placeholder(h_name, h_loader);
1092 assert(check == check2, "name inconsistancy in SystemDictionary");
1093 }
1094 } );
1095
1096 return k();
1097 }
1098
1099
1100 void SystemDictionary::set_shared_dictionary(HashtableBucket* t, int length,
1101 int number_of_entries) {
1102 assert(length == _nof_buckets * sizeof(HashtableBucket),
1103 "bad shared dictionary size.");
1104 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1105 }
1106
1107
1108 // If there is a shared dictionary, then find the entry for the
1109 // given shared system class, if any.
1110
1111 klassOop SystemDictionary::find_shared_class(symbolHandle class_name) {
1112 if (shared_dictionary() != NULL) {
1113 unsigned int d_hash = dictionary()->compute_hash(class_name, Handle());
1114 int d_index = dictionary()->hash_to_index(d_hash);
1115 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1116 } else {
1117 return NULL;
1118 }
1119 }
1120
1121
1122 // Load a class from the shared spaces (found through the shared system
1123 // dictionary). Force the superclass and all interfaces to be loaded.
1124 // Update the class definition to include sibling classes and no
1125 // subclasses (yet). [Classes in the shared space are not part of the
1126 // object hierarchy until loaded.]
1127
1128 instanceKlassHandle SystemDictionary::load_shared_class(
1129 symbolHandle class_name, Handle class_loader, TRAPS) {
1130 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1131 return load_shared_class(ik, class_loader, THREAD);
1132 }
1133
1134 // Note well! Changes to this method may affect oop access order
1135 // in the shared archive. Please take care to not make changes that
1136 // adversely affect cold start time by changing the oop access order
1137 // that is specified in dump.cpp MarkAndMoveOrderedReadOnly and
1138 // MarkAndMoveOrderedReadWrite closures.
1139 instanceKlassHandle SystemDictionary::load_shared_class(
1140 instanceKlassHandle ik, Handle class_loader, TRAPS) {
1141 assert(class_loader.is_null(), "non-null classloader for shared class?");
1142 if (ik.not_null()) {
1143 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1144 symbolHandle class_name(THREAD, ik->name());
1145
1146 // Found the class, now load the superclass and interfaces. If they
1147 // are shared, add them to the main system dictionary and reset
1148 // their hierarchy references (supers, subs, and interfaces).
1149
1150 if (ik->super() != NULL) {
1151 symbolHandle cn(THREAD, ik->super()->klass_part()->name());
1152 resolve_super_or_fail(class_name, cn,
1153 class_loader, Handle(), true, CHECK_(nh));
1154 }
1155
1156 objArrayHandle interfaces (THREAD, ik->local_interfaces());
1157 int num_interfaces = interfaces->length();
1158 for (int index = 0; index < num_interfaces; index++) {
1159 klassOop k = klassOop(interfaces->obj_at(index));
1160
1161 // Note: can not use instanceKlass::cast here because
1162 // interfaces' instanceKlass's C++ vtbls haven't been
1163 // reinitialized yet (they will be once the interface classes
1164 // are loaded)
1165 symbolHandle name (THREAD, k->klass_part()->name());
1166 resolve_super_or_fail(class_name, name, class_loader, Handle(), false, CHECK_(nh));
1167 }
1168
1169 // Adjust methods to recover missing data. They need addresses for
1170 // interpreter entry points and their default native method address
1171 // must be reset.
1172
1173 // Updating methods must be done under a lock so multiple
1174 // threads don't update these in parallel
1175 // Shared classes are all currently loaded by the bootstrap
1176 // classloader, so this will never cause a deadlock on
1177 // a custom class loader lock.
1178
1179 {
1180 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1181 check_loader_lock_contention(lockObject, THREAD);
1182 ObjectLocker ol(lockObject, THREAD, true);
1183
1184 objArrayHandle methods (THREAD, ik->methods());
1185 int num_methods = methods->length();
1186 for (int index2 = 0; index2 < num_methods; ++index2) {
1187 methodHandle m(THREAD, methodOop(methods->obj_at(index2)));
1188 m()->link_method(m, CHECK_(nh));
1189 }
1190 }
1191
1192 if (TraceClassLoading) {
1193 ResourceMark rm;
1194 tty->print("[Loaded %s", ik->external_name());
1195 tty->print(" from shared objects file");
1196 tty->print_cr("]");
1197 }
1198 // notify a class loaded from shared object
1199 ClassLoadingService::notify_class_loaded(instanceKlass::cast(ik()),
1200 true /* shared class */);
1201 }
1202 return ik;
1203 }
1204
1205 #ifdef KERNEL
1206 // Some classes on the bootstrap class path haven't been installed on the
1207 // system yet. Call the DownloadManager method to make them appear in the
1208 // bootstrap class path and try again to load the named class.
1209 // Note that with delegation class loaders all classes in another loader will
1210 // first try to call this so it'd better be fast!!
1211 static instanceKlassHandle download_and_retry_class_load(
1212 symbolHandle class_name,
1213 TRAPS) {
1214
1215 klassOop dlm = SystemDictionary::sun_jkernel_DownloadManager_klass();
1216 instanceKlassHandle nk;
1217
1218 // If download manager class isn't loaded just return.
1219 if (dlm == NULL) return nk;
1220
1221 { HandleMark hm(THREAD);
1222 ResourceMark rm(THREAD);
1223 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nk));
1224 Handle class_string = java_lang_String::externalize_classname(s, CHECK_(nk));
1225
1226 // return value
1227 JavaValue result(T_OBJECT);
1228
1229 // Call the DownloadManager. We assume that it has a lock because
1230 // multiple classes could be not found and downloaded at the same time.
1231 // class sun.misc.DownloadManager;
1232 // public static String getBootClassPathEntryForClass(String className);
1233 JavaCalls::call_static(&result,
1234 KlassHandle(THREAD, dlm),
1235 vmSymbolHandles::getBootClassPathEntryForClass_name(),
1236 vmSymbolHandles::string_string_signature(),
1237 class_string,
1238 CHECK_(nk));
1239
1240 // Get result.string and add to bootclasspath
1241 assert(result.get_type() == T_OBJECT, "just checking");
1242 oop obj = (oop) result.get_jobject();
1243 if (obj == NULL) { return nk; }
1244
1245 char* new_class_name = java_lang_String::as_utf8_string(obj);
1246
1247 // lock the loader
1248 // we use this lock because JVMTI does.
1249 Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
1250
1251 ObjectLocker ol(loader_lock, THREAD);
1252 // add the file to the bootclasspath
1253 ClassLoader::update_class_path_entry_list(new_class_name, true);
1254 } // end HandleMark
1255
1256 if (TraceClassLoading) {
1257 ClassLoader::print_bootclasspath();
1258 }
1259 return ClassLoader::load_classfile(class_name, CHECK_(nk));
1260 }
1261 #endif // KERNEL
1262
1263
1264 instanceKlassHandle SystemDictionary::load_instance_class(symbolHandle class_name, Handle class_loader, TRAPS) {
1265 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1266 if (class_loader.is_null()) {
1267 // Search the shared system dictionary for classes preloaded into the
1268 // shared spaces.
1269 instanceKlassHandle k;
1270 k = load_shared_class(class_name, class_loader, THREAD);
1271
1272 if (k.is_null()) {
1273 // Use VM class loader
1274 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1275 }
1276
1277 #ifdef KERNEL
1278 // If the VM class loader has failed to load the class, call the
1279 // DownloadManager class to make it magically appear on the classpath
1280 // and try again. This is only configured with the Kernel VM.
1281 if (k.is_null()) {
1282 k = download_and_retry_class_load(class_name, CHECK_(nh));
1283 }
1284 #endif // KERNEL
1285
1286 // find_or_define_instance_class may return a different k
1287 if (!k.is_null()) {
1288 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1289 }
1290 return k;
1291 } else {
1292 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1293 ResourceMark rm(THREAD);
1294
1295 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1296 // Translate to external class name format, i.e., convert '/' chars to '.'
1297 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1298
1299 JavaValue result(T_OBJECT);
1300
1301 KlassHandle spec_klass (THREAD, SystemDictionary::classloader_klass());
1302
1303 // UnsyncloadClass option means don't synchronize loadClass() calls.
1304 // loadClassInternal() is synchronized and public loadClass(String) is not.
1305 // This flag is for diagnostic purposes only. It is risky to call
1306 // custom class loaders without synchronization.
1307 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1308 // findClass, this flag risks unexpected timing bugs in the field.
1309 // Do NOT assume this will be supported in future releases.
1310 if (!UnsyncloadClass && has_loadClassInternal()) {
1311 JavaCalls::call_special(&result,
1312 class_loader,
1313 spec_klass,
1314 vmSymbolHandles::loadClassInternal_name(),
1315 vmSymbolHandles::string_class_signature(),
1316 string,
1317 CHECK_(nh));
1318 } else {
1319 JavaCalls::call_virtual(&result,
1320 class_loader,
1321 spec_klass,
1322 vmSymbolHandles::loadClass_name(),
1323 vmSymbolHandles::string_class_signature(),
1324 string,
1325 CHECK_(nh));
1326 }
1327
1328 assert(result.get_type() == T_OBJECT, "just checking");
1329 oop obj = (oop) result.get_jobject();
1330
1331 // Primitive classes return null since forName() can not be
1332 // used to obtain any of the Class objects representing primitives or void
1333 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1334 instanceKlassHandle k =
1335 instanceKlassHandle(THREAD, java_lang_Class::as_klassOop(obj));
1336 // For user defined Java class loaders, check that the name returned is
1337 // the same as that requested. This check is done for the bootstrap
1338 // loader when parsing the class file.
1339 if (class_name() == k->name()) {
1340 return k;
1341 }
1342 }
1343 // Class is not found or has the wrong name, return NULL
1344 return nh;
1345 }
1346 }
1347
1348 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1349
1350 Handle class_loader_h(THREAD, k->class_loader());
1351
1352 // for bootstrap classloader don't acquire lock
1353 if (!class_loader_h.is_null()) {
1354 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1355 compute_loader_lock_object(class_loader_h, THREAD)),
1356 "define called without lock");
1357 }
1358
1359
1360 // Check class-loading constraints. Throw exception if violation is detected.
1361 // Grabs and releases SystemDictionary_lock
1362 // The check_constraints/find_class call and update_dictionary sequence
1363 // must be "atomic" for a specific class/classloader pair so we never
1364 // define two different instanceKlasses for that class/classloader pair.
1365 // Existing classloaders will call define_instance_class with the
1366 // classloader lock held
1367 // Parallel classloaders will call find_or_define_instance_class
1368 // which will require a token to perform the define class
1369 symbolHandle name_h(THREAD, k->name());
1370 unsigned int d_hash = dictionary()->compute_hash(name_h, class_loader_h);
1371 int d_index = dictionary()->hash_to_index(d_hash);
1372 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1373
1374 // Register class just loaded with class loader (placed in Vector)
1375 // Note we do this before updating the dictionary, as this can
1376 // fail with an OutOfMemoryError (if it does, we will *not* put this
1377 // class in the dictionary and will not update the class hierarchy).
1378 if (k->class_loader() != NULL) {
1379 methodHandle m(THREAD, Universe::loader_addClass_method());
1380 JavaValue result(T_VOID);
1381 JavaCallArguments args(class_loader_h);
1382 args.push_oop(Handle(THREAD, k->java_mirror()));
1383 JavaCalls::call(&result, m, &args, CHECK);
1384 }
1385
1386 // Add the new class. We need recompile lock during update of CHA.
1387 {
1388 unsigned int p_hash = placeholders()->compute_hash(name_h, class_loader_h);
1389 int p_index = placeholders()->hash_to_index(p_hash);
1390
1391 MutexLocker mu_r(Compile_lock, THREAD);
1392
1393 // Add to class hierarchy, initialize vtables, and do possible
1394 // deoptimizations.
1395 add_to_hierarchy(k, CHECK); // No exception, but can block
1396
1397 // Add to systemDictionary - so other classes can see it.
1398 // Grabs and releases SystemDictionary_lock
1399 update_dictionary(d_index, d_hash, p_index, p_hash,
1400 k, class_loader_h, THREAD);
1401 }
1402 k->eager_initialize(THREAD);
1403
1404 // notify jvmti
1405 if (JvmtiExport::should_post_class_load()) {
1406 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1407 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1408
1409 }
1410 }
1411
1412 // Support parallel classloading
1413 // Initial implementation for bootstrap classloader
1414 // For future:
1415 // For custom class loaders that support parallel classloading,
1416 // in case they do not synchronize around
1417 // FindLoadedClass/DefineClass calls, we check for parallel
1418 // loading for them, wait if a defineClass is in progress
1419 // and return the initial requestor's results
1420 // For better performance, the class loaders should synchronize
1421 // findClass(), i.e. FindLoadedClass/DefineClass or they
1422 // potentially waste time reading and parsing the bytestream.
1423 // Note: VM callers should ensure consistency of k/class_name,class_loader
1424 instanceKlassHandle SystemDictionary::find_or_define_instance_class(symbolHandle class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1425
1426 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1427
1428 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1429 int d_index = dictionary()->hash_to_index(d_hash);
1430
1431 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1432 unsigned int p_hash = placeholders()->compute_hash(class_name, class_loader);
1433 int p_index = placeholders()->hash_to_index(p_hash);
1434 PlaceholderEntry* probe;
1435
1436 {
1437 MutexLocker mu(SystemDictionary_lock, THREAD);
1438 // First check if class already defined
1439 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1440 if (check != NULL) {
1441 return(instanceKlassHandle(THREAD, check));
1442 }
1443
1444 // Acquire define token for this class/classloader
1445 symbolHandle nullsymbolHandle;
1446 probe = placeholders()->find_and_add(p_index, p_hash, class_name, class_loader, PlaceholderTable::DEFINE_CLASS, nullsymbolHandle, THREAD);
1447 // Check if another thread defining in parallel
1448 if (probe->definer() == NULL) {
1449 // Thread will define the class
1450 probe->set_definer(THREAD);
1451 } else {
1452 // Wait for defining thread to finish and return results
1453 while (probe->definer() != NULL) {
1454 SystemDictionary_lock->wait();
1455 }
1456 if (probe->instanceKlass() != NULL) {
1457 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1458 return(instanceKlassHandle(THREAD, probe->instanceKlass()));
1459 } else {
1460 // If definer had an error, try again as any new thread would
1461 probe->set_definer(THREAD);
1462 #ifdef ASSERT
1463 klassOop check = find_class(d_index, d_hash, class_name, class_loader);
1464 assert(check == NULL, "definer missed recording success");
1465 #endif
1466 }
1467 }
1468 }
1469
1470 define_instance_class(k, THREAD);
1471
1472 Handle linkage_exception = Handle(); // null handle
1473
1474 // definer must notify any waiting threads
1475 {
1476 MutexLocker mu(SystemDictionary_lock, THREAD);
1477 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, class_name, class_loader);
1478 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1479 if (probe != NULL) {
1480 if (HAS_PENDING_EXCEPTION) {
1481 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1482 CLEAR_PENDING_EXCEPTION;
1483 } else {
1484 probe->set_instanceKlass(k());
1485 }
1486 probe->set_definer(NULL);
1487 probe->remove_seen_thread(THREAD, PlaceholderTable::DEFINE_CLASS);
1488 SystemDictionary_lock->notify_all();
1489 }
1490 }
1491
1492 // Can't throw exception while holding lock due to rank ordering
1493 if (linkage_exception() != NULL) {
1494 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1495 }
1496
1497 return k;
1498 }
1499
1500 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1501 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1502 if (class_loader.is_null()) {
1503 return Handle(THREAD, _system_loader_lock_obj);
1504 } else {
1505 return class_loader;
1506 }
1507 }
1508
1509 // This method is added to check how often we have to wait to grab loader
1510 // lock. The results are being recorded in the performance counters defined in
1511 // ClassLoader::_sync_systemLoaderLockContentionRate and
1512 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1513 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1514 if (!UsePerfData) {
1515 return;
1516 }
1517
1518 assert(!loader_lock.is_null(), "NULL lock object");
1519
1520 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1521 == ObjectSynchronizer::owner_other) {
1522 // contention will likely happen, so increment the corresponding
1523 // contention counter.
1524 if (loader_lock() == _system_loader_lock_obj) {
1525 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1526 } else {
1527 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1528 }
1529 }
1530 }
1531
1532 // ----------------------------------------------------------------------------
1533 // Lookup
1534
1535 klassOop SystemDictionary::find_class(int index, unsigned int hash,
1536 symbolHandle class_name,
1537 Handle class_loader) {
1538 assert_locked_or_safepoint(SystemDictionary_lock);
1539 assert (index == dictionary()->index_for(class_name, class_loader),
1540 "incorrect index?");
1541
1542 klassOop k = dictionary()->find_class(index, hash, class_name, class_loader);
1543 return k;
1544 }
1545
1546
1547 // Basic find on classes in the midst of being loaded
1548 symbolOop SystemDictionary::find_placeholder(int index, unsigned int hash,
1549 symbolHandle class_name,
1550 Handle class_loader) {
1551 assert_locked_or_safepoint(SystemDictionary_lock);
1552
1553 return placeholders()->find_entry(index, hash, class_name, class_loader);
1554 }
1555
1556
1557 // Used for assertions and verification only
1558 oop SystemDictionary::find_class_or_placeholder(symbolHandle class_name,
1559 Handle class_loader) {
1560 #ifndef ASSERT
1561 guarantee(VerifyBeforeGC ||
1562 VerifyDuringGC ||
1563 VerifyBeforeExit ||
1564 VerifyAfterGC, "too expensive");
1565 #endif
1566 assert_locked_or_safepoint(SystemDictionary_lock);
1567 symbolOop class_name_ = class_name();
1568 oop class_loader_ = class_loader();
1569
1570 // First look in the loaded class array
1571 unsigned int d_hash = dictionary()->compute_hash(class_name, class_loader);
1572 int d_index = dictionary()->hash_to_index(d_hash);
1573 oop lookup = find_class(d_index, d_hash, class_name, class_loader);
1574
1575 if (lookup == NULL) {
1576 // Next try the placeholders
1577 unsigned int p_hash = placeholders()->compute_hash(class_name,class_loader);
1578 int p_index = placeholders()->hash_to_index(p_hash);
1579 lookup = find_placeholder(p_index, p_hash, class_name, class_loader);
1580 }
1581
1582 return lookup;
1583 }
1584
1585
1586 // Get the next class in the diictionary.
1587 klassOop SystemDictionary::try_get_next_class() {
1588 return dictionary()->try_get_next_class();
1589 }
1590
1591
1592 // ----------------------------------------------------------------------------
1593 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1594 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1595 // before a new class is used.
1596
1597 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1598 assert(k.not_null(), "just checking");
1599 // Link into hierachy. Make sure the vtables are initialized before linking into
1600 k->append_to_sibling_list(); // add to superklass/sibling list
1601 k->process_interfaces(THREAD); // handle all "implements" declarations
1602 k->set_init_state(instanceKlass::loaded);
1603 // Now flush all code that depended on old class hierarchy.
1604 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1605 // Also, first reinitialize vtable because it may have gotten out of synch
1606 // while the new class wasn't connected to the class hierarchy.
1607 Universe::flush_dependents_on(k);
1608 }
1609
1610
1611 // ----------------------------------------------------------------------------
1612 // GC support
1613
1614 // Following roots during mark-sweep is separated in two phases.
1615 //
1616 // The first phase follows preloaded classes and all other system
1617 // classes, since these will never get unloaded anyway.
1618 //
1619 // The second phase removes (unloads) unreachable classes from the
1620 // system dictionary and follows the remaining classes' contents.
1621
1622 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1623 // Follow preloaded classes/mirrors and system loader object
1624 blk->do_oop(&_java_system_loader);
1625 preloaded_oops_do(blk);
1626 always_strong_classes_do(blk);
1627 }
1628
1629
1630 void SystemDictionary::always_strong_classes_do(OopClosure* blk) {
1631 // Follow all system classes and temporary placeholders in dictionary
1632 dictionary()->always_strong_classes_do(blk);
1633
1634 // Placeholders. These are *always* strong roots, as they
1635 // represent classes we're actively loading.
1636 placeholders_do(blk);
1637
1638 // Loader constraints. We must keep the symbolOop used in the name alive.
1639 constraints()->always_strong_classes_do(blk);
1640
1641 // Resolution errors keep the symbolOop for the error alive
1642 resolution_errors()->always_strong_classes_do(blk);
1643 }
1644
1645
1646 void SystemDictionary::placeholders_do(OopClosure* blk) {
1647 placeholders()->oops_do(blk);
1648 }
1649
1650
1651 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive) {
1652 bool result = dictionary()->do_unloading(is_alive);
1653 constraints()->purge_loader_constraints(is_alive);
1654 resolution_errors()->purge_resolution_errors(is_alive);
1655 return result;
1656 }
1657
1658
1659 // The mirrors are scanned by shared_oops_do() which is
1660 // not called by oops_do(). In order to process oops in
1661 // a necessary order, shared_oops_do() is call by
1662 // Universe::oops_do().
1663 void SystemDictionary::oops_do(OopClosure* f) {
1664 // Adjust preloaded classes and system loader object
1665 f->do_oop(&_java_system_loader);
1666 preloaded_oops_do(f);
1667
1668 lazily_loaded_oops_do(f);
1669
1670 // Adjust dictionary
1671 dictionary()->oops_do(f);
1672
1673 // Partially loaded classes
1674 placeholders()->oops_do(f);
1675
1676 // Adjust constraint table
1677 constraints()->oops_do(f);
1678
1679 // Adjust resolution error table
1680 resolution_errors()->oops_do(f);
1681 }
1682
1683
1684 void SystemDictionary::preloaded_oops_do(OopClosure* f) {
1685 f->do_oop((oop*) &_string_klass);
1686 f->do_oop((oop*) &_object_klass);
1687 f->do_oop((oop*) &_class_klass);
1688 f->do_oop((oop*) &_cloneable_klass);
1689 f->do_oop((oop*) &_classloader_klass);
1690 f->do_oop((oop*) &_serializable_klass);
1691 f->do_oop((oop*) &_system_klass);
1692
1693 f->do_oop((oop*) &_throwable_klass);
1694 f->do_oop((oop*) &_error_klass);
1695 f->do_oop((oop*) &_threaddeath_klass);
1696 f->do_oop((oop*) &_exception_klass);
1697 f->do_oop((oop*) &_runtime_exception_klass);
1698 f->do_oop((oop*) &_classNotFoundException_klass);
1699 f->do_oop((oop*) &_noClassDefFoundError_klass);
1700 f->do_oop((oop*) &_linkageError_klass);
1701 f->do_oop((oop*) &_classCastException_klass);
1702 f->do_oop((oop*) &_arrayStoreException_klass);
1703 f->do_oop((oop*) &_virtualMachineError_klass);
1704 f->do_oop((oop*) &_outOfMemoryError_klass);
1705 f->do_oop((oop*) &_StackOverflowError_klass);
1706 f->do_oop((oop*) &_illegalMonitorStateException_klass);
1707 f->do_oop((oop*) &_protectionDomain_klass);
1708 f->do_oop((oop*) &_AccessControlContext_klass);
1709
1710 f->do_oop((oop*) &_reference_klass);
1711 f->do_oop((oop*) &_soft_reference_klass);
1712 f->do_oop((oop*) &_weak_reference_klass);
1713 f->do_oop((oop*) &_final_reference_klass);
1714 f->do_oop((oop*) &_phantom_reference_klass);
1715 f->do_oop((oop*) &_finalizer_klass);
1716
1717 f->do_oop((oop*) &_thread_klass);
1718 f->do_oop((oop*) &_threadGroup_klass);
1719 f->do_oop((oop*) &_properties_klass);
1720 f->do_oop((oop*) &_reflect_accessible_object_klass);
1721 f->do_oop((oop*) &_reflect_field_klass);
1722 f->do_oop((oop*) &_reflect_method_klass);
1723 f->do_oop((oop*) &_reflect_constructor_klass);
1724 f->do_oop((oop*) &_reflect_magic_klass);
1725 f->do_oop((oop*) &_reflect_method_accessor_klass);
1726 f->do_oop((oop*) &_reflect_constructor_accessor_klass);
1727 f->do_oop((oop*) &_reflect_delegating_classloader_klass);
1728 f->do_oop((oop*) &_reflect_constant_pool_klass);
1729 f->do_oop((oop*) &_reflect_unsafe_static_field_accessor_impl_klass);
1730
1731 f->do_oop((oop*) &_stringBuffer_klass);
1732 f->do_oop((oop*) &_vector_klass);
1733 f->do_oop((oop*) &_hashtable_klass);
1734
1735 f->do_oop((oop*) &_stackTraceElement_klass);
1736
1737 f->do_oop((oop*) &_java_nio_Buffer_klass);
1738
1739 f->do_oop((oop*) &_sun_misc_AtomicLongCSImpl_klass);
1740 f->do_oop((oop*) &_sun_jkernel_DownloadManager_klass);
1741
1742 f->do_oop((oop*) &_boolean_klass);
1743 f->do_oop((oop*) &_char_klass);
1744 f->do_oop((oop*) &_float_klass);
1745 f->do_oop((oop*) &_double_klass);
1746 f->do_oop((oop*) &_byte_klass);
1747 f->do_oop((oop*) &_short_klass);
1748 f->do_oop((oop*) &_int_klass);
1749 f->do_oop((oop*) &_long_klass);
1750 {
1751 for (int i = 0; i < T_VOID+1; i++) {
1752 if (_box_klasses[i] != NULL) {
1753 assert(i >= T_BOOLEAN, "checking");
1754 f->do_oop((oop*) &_box_klasses[i]);
1755 }
1756 }
1757 }
1758
1759 // The basic type mirrors would have already been processed in
1760 // Universe::oops_do(), via a call to shared_oops_do(), so should
1761 // not be processed again.
1762
1763 f->do_oop((oop*) &_system_loader_lock_obj);
1764 FilteredFieldsMap::klasses_oops_do(f);
1765 }
1766
1767 void SystemDictionary::lazily_loaded_oops_do(OopClosure* f) {
1768 f->do_oop((oop*) &_abstract_ownable_synchronizer_klass);
1769 }
1770
1771 // Just the classes from defining class loaders
1772 // Don't iterate over placeholders
1773 void SystemDictionary::classes_do(void f(klassOop)) {
1774 dictionary()->classes_do(f);
1775 }
1776
1777 // Added for initialize_itable_for_klass
1778 // Just the classes from defining class loaders
1779 // Don't iterate over placeholders
1780 void SystemDictionary::classes_do(void f(klassOop, TRAPS), TRAPS) {
1781 dictionary()->classes_do(f, CHECK);
1782 }
1783
1784 // All classes, and their class loaders
1785 // Don't iterate over placeholders
1786 void SystemDictionary::classes_do(void f(klassOop, oop)) {
1787 dictionary()->classes_do(f);
1788 }
1789
1790 // All classes, and their class loaders
1791 // (added for helpers that use HandleMarks and ResourceMarks)
1792 // Don't iterate over placeholders
1793 void SystemDictionary::classes_do(void f(klassOop, oop, TRAPS), TRAPS) {
1794 dictionary()->classes_do(f, CHECK);
1795 }
1796
1797 void SystemDictionary::placeholders_do(void f(symbolOop, oop)) {
1798 placeholders()->entries_do(f);
1799 }
1800
1801 void SystemDictionary::methods_do(void f(methodOop)) {
1802 dictionary()->methods_do(f);
1803 }
1804
1805 // ----------------------------------------------------------------------------
1806 // Lazily load klasses
1807
1808 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1809 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1810
1811 // if multiple threads calling this function, only one thread will load
1812 // the class. The other threads will find the loaded version once the
1813 // class is loaded.
1814 klassOop aos = _abstract_ownable_synchronizer_klass;
1815 if (aos == NULL) {
1816 klassOop k = resolve_or_fail(vmSymbolHandles::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1817 // Force a fence to prevent any read before the write completes
1818 OrderAccess::fence();
1819 _abstract_ownable_synchronizer_klass = k;
1820 }
1821 }
1822
1823 // ----------------------------------------------------------------------------
1824 // Initialization
1825
1826 void SystemDictionary::initialize(TRAPS) {
1827 // Allocate arrays
1828 assert(dictionary() == NULL,
1829 "SystemDictionary should only be initialized once");
1830 _dictionary = new Dictionary(_nof_buckets);
1831 _placeholders = new PlaceholderTable(_nof_buckets);
1832 _number_of_modifications = 0;
1833 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1834 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1835
1836 // Allocate private object used as system class loader lock
1837 _system_loader_lock_obj = oopFactory::new_system_objArray(0, CHECK);
1838 // Initialize basic classes
1839 initialize_preloaded_classes(CHECK);
1840 }
1841
1842
1843 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1844 assert(_object_klass == NULL, "preloaded classes should only be initialized once");
1845 // Preload commonly used klasses
1846 _object_klass = resolve_or_fail(vmSymbolHandles::java_lang_Object(), true, CHECK);
1847 _string_klass = resolve_or_fail(vmSymbolHandles::java_lang_String(), true, CHECK);
1848 _class_klass = resolve_or_fail(vmSymbolHandles::java_lang_Class(), true, CHECK);
1849 debug_only(instanceKlass::verify_class_klass_nonstatic_oop_maps(_class_klass));
1850 // Fixup mirrors for classes loaded before java.lang.Class.
1851 // These calls iterate over the objects currently in the perm gen
1852 // so calling them at this point is matters (not before when there
1853 // are fewer objects and not later after there are more objects
1854 // in the perm gen.
1855 Universe::initialize_basic_type_mirrors(CHECK);
1856 Universe::fixup_mirrors(CHECK);
1857
1858 _cloneable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Cloneable(), true, CHECK);
1859 _classloader_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassLoader(), true, CHECK);
1860 _serializable_klass = resolve_or_fail(vmSymbolHandles::java_io_Serializable(), true, CHECK);
1861 _system_klass = resolve_or_fail(vmSymbolHandles::java_lang_System(), true, CHECK);
1862
1863 _throwable_klass = resolve_or_fail(vmSymbolHandles::java_lang_Throwable(), true, CHECK);
1864 _error_klass = resolve_or_fail(vmSymbolHandles::java_lang_Error(), true, CHECK);
1865 _threaddeath_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadDeath(), true, CHECK);
1866 _exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_Exception(), true, CHECK);
1867 _runtime_exception_klass = resolve_or_fail(vmSymbolHandles::java_lang_RuntimeException(), true, CHECK);
1868 _protectionDomain_klass = resolve_or_fail(vmSymbolHandles::java_security_ProtectionDomain(), true, CHECK);
1869 _AccessControlContext_klass = resolve_or_fail(vmSymbolHandles::java_security_AccessControlContext(), true, CHECK);
1870 _classNotFoundException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassNotFoundException(), true, CHECK);
1871 _noClassDefFoundError_klass = resolve_or_fail(vmSymbolHandles::java_lang_NoClassDefFoundError(), true, CHECK);
1872 _linkageError_klass = resolve_or_fail(vmSymbolHandles::java_lang_LinkageError(), true, CHECK);
1873 _classCastException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ClassCastException(), true, CHECK);
1874 _arrayStoreException_klass = resolve_or_fail(vmSymbolHandles::java_lang_ArrayStoreException(), true, CHECK);
1875 _virtualMachineError_klass = resolve_or_fail(vmSymbolHandles::java_lang_VirtualMachineError(), true, CHECK);
1876 _outOfMemoryError_klass = resolve_or_fail(vmSymbolHandles::java_lang_OutOfMemoryError(), true, CHECK);
1877 _StackOverflowError_klass = resolve_or_fail(vmSymbolHandles::java_lang_StackOverflowError(), true, CHECK);
1878 _illegalMonitorStateException_klass = resolve_or_fail(vmSymbolHandles::java_lang_IllegalMonitorStateException(), true, CHECK);
1879
1880 // Preload ref klasses and set reference types
1881 _reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Reference(), true, CHECK);
1882 instanceKlass::cast(_reference_klass)->set_reference_type(REF_OTHER);
1883 instanceRefKlass::update_nonstatic_oop_maps(_reference_klass);
1884
1885 _soft_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_SoftReference(), true, CHECK);
1886 instanceKlass::cast(_soft_reference_klass)->set_reference_type(REF_SOFT);
1887 _weak_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_WeakReference(), true, CHECK);
1888 instanceKlass::cast(_weak_reference_klass)->set_reference_type(REF_WEAK);
1889 _final_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_FinalReference(), true, CHECK);
1890 instanceKlass::cast(_final_reference_klass)->set_reference_type(REF_FINAL);
1891 _phantom_reference_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_PhantomReference(), true, CHECK);
1892 instanceKlass::cast(_phantom_reference_klass)->set_reference_type(REF_PHANTOM);
1893 _finalizer_klass = resolve_or_fail(vmSymbolHandles::java_lang_ref_Finalizer(), true, CHECK);
1894
1895 _thread_klass = resolve_or_fail(vmSymbolHandles::java_lang_Thread(), true, CHECK);
1896 _threadGroup_klass = resolve_or_fail(vmSymbolHandles::java_lang_ThreadGroup(), true, CHECK);
1897 _properties_klass = resolve_or_fail(vmSymbolHandles::java_util_Properties(), true, CHECK);
1898 _reflect_accessible_object_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_AccessibleObject(), true, CHECK);
1899 _reflect_field_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Field(), true, CHECK);
1900 _reflect_method_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Method(), true, CHECK);
1901 _reflect_constructor_klass = resolve_or_fail(vmSymbolHandles::java_lang_reflect_Constructor(), true, CHECK);
1902 // Universe::is_gte_jdk14x_version() is not set up by this point.
1903 // It's okay if these turn out to be NULL in non-1.4 JDKs.
1904 _reflect_magic_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MagicAccessorImpl(), CHECK);
1905 _reflect_method_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_MethodAccessorImpl(), CHECK);
1906 _reflect_constructor_accessor_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstructorAccessorImpl(), CHECK);
1907 _reflect_delegating_classloader_klass = resolve_or_null(vmSymbolHandles::sun_reflect_DelegatingClassLoader(), CHECK);
1908 _reflect_constant_pool_klass = resolve_or_null(vmSymbolHandles::sun_reflect_ConstantPool(), CHECK);
1909 _reflect_unsafe_static_field_accessor_impl_klass = resolve_or_null(vmSymbolHandles::sun_reflect_UnsafeStaticFieldAccessorImpl(), CHECK);
1910
1911 _vector_klass = resolve_or_fail(vmSymbolHandles::java_util_Vector(), true, CHECK);
1912 _hashtable_klass = resolve_or_fail(vmSymbolHandles::java_util_Hashtable(), true, CHECK);
1913 _stringBuffer_klass = resolve_or_fail(vmSymbolHandles::java_lang_StringBuffer(), true, CHECK);
1914
1915 // It's NULL in non-1.4 JDKs.
1916 _stackTraceElement_klass = resolve_or_null(vmSymbolHandles::java_lang_StackTraceElement(), CHECK);
1917
1918 // Universe::is_gte_jdk14x_version() is not set up by this point.
1919 // It's okay if this turns out to be NULL in non-1.4 JDKs.
1920 _java_nio_Buffer_klass = resolve_or_null(vmSymbolHandles::java_nio_Buffer(), CHECK);
1921
1922 // If this class isn't present, it won't be referenced.
1923 _sun_misc_AtomicLongCSImpl_klass = resolve_or_null(vmSymbolHandles::sun_misc_AtomicLongCSImpl(), CHECK);
1924 #ifdef KERNEL
1925 _sun_jkernel_DownloadManager_klass = resolve_or_null(vmSymbolHandles::sun_jkernel_DownloadManager(), CHECK);
1926 if (_sun_jkernel_DownloadManager_klass == NULL) {
1927 warning("Cannot find sun/jkernel/DownloadManager");
1928 }
1929 #endif // KERNEL
1930
1931 // Preload boxing klasses
1932 _boolean_klass = resolve_or_fail(vmSymbolHandles::java_lang_Boolean(), true, CHECK);
1933 _char_klass = resolve_or_fail(vmSymbolHandles::java_lang_Character(), true, CHECK);
1934 _float_klass = resolve_or_fail(vmSymbolHandles::java_lang_Float(), true, CHECK);
1935 _double_klass = resolve_or_fail(vmSymbolHandles::java_lang_Double(), true, CHECK);
1936 _byte_klass = resolve_or_fail(vmSymbolHandles::java_lang_Byte(), true, CHECK);
1937 _short_klass = resolve_or_fail(vmSymbolHandles::java_lang_Short(), true, CHECK);
1938 _int_klass = resolve_or_fail(vmSymbolHandles::java_lang_Integer(), true, CHECK);
1939 _long_klass = resolve_or_fail(vmSymbolHandles::java_lang_Long(), true, CHECK);
1940
1941 _box_klasses[T_BOOLEAN] = _boolean_klass;
1942 _box_klasses[T_CHAR] = _char_klass;
1943 _box_klasses[T_FLOAT] = _float_klass;
1944 _box_klasses[T_DOUBLE] = _double_klass;
1945 _box_klasses[T_BYTE] = _byte_klass;
1946 _box_klasses[T_SHORT] = _short_klass;
1947 _box_klasses[T_INT] = _int_klass;
1948 _box_klasses[T_LONG] = _long_klass;
1949 //_box_klasses[T_OBJECT] = _object_klass;
1950 //_box_klasses[T_ARRAY] = _object_klass;
1951
1952 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
1953 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
1954 _has_loadClassInternal = (method != NULL);
1955 }
1956
1957 { // Compute whether we should use checkPackageAccess or NOT
1958 methodOop method = instanceKlass::cast(classloader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
1959 _has_checkPackageAccess = (method != NULL);
1960 }
1961 }
1962
1963 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
1964 // If so, returns the basic type it holds. If not, returns T_OBJECT.
1965 BasicType SystemDictionary::box_klass_type(klassOop k) {
1966 assert(k != NULL, "");
1967 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
1968 if (_box_klasses[i] == k)
1969 return (BasicType)i;
1970 }
1971 return T_OBJECT;
1972 }
1973
1974 // Constraints on class loaders. The details of the algorithm can be
1975 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
1976 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
1977 // that the system dictionary needs to maintain a set of contraints that
1978 // must be satisfied by all classes in the dictionary.
1979 // if defining is true, then LinkageError if already in systemDictionary
1980 // if initiating loader, then ok if instanceKlass matches existing entry
1981
1982 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
1983 instanceKlassHandle k,
1984 Handle class_loader, bool defining,
1985 TRAPS) {
1986 const char *linkage_error = NULL;
1987 {
1988 symbolHandle name (THREAD, k->name());
1989 MutexLocker mu(SystemDictionary_lock, THREAD);
1990
1991 klassOop check = find_class(d_index, d_hash, name, class_loader);
1992 if (check != (klassOop)NULL) {
1993 // if different instanceKlass - duplicate class definition,
1994 // else - ok, class loaded by a different thread in parallel,
1995 // we should only have found it if it was done loading and ok to use
1996 // system dictionary only holds instance classes, placeholders
1997 // also holds array classes
1998
1999 assert(check->klass_part()->oop_is_instance(), "noninstance in systemdictionary");
2000 if ((defining == true) || (k() != check)) {
2001 linkage_error = "loader (instance of %s): attempted duplicate class "
2002 "definition for name: \"%s\"";
2003 } else {
2004 return;
2005 }
2006 }
2007
2008 #ifdef ASSERT
2009 unsigned int p_hash = placeholders()->compute_hash(name, class_loader);
2010 int p_index = placeholders()->hash_to_index(p_hash);
2011 symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2012 assert(ph_check == NULL || ph_check == name(), "invalid symbol");
2013 #endif
2014
2015 if (linkage_error == NULL) {
2016 if (constraints()->check_or_update(k, class_loader, name) == false) {
2017 linkage_error = "loader constraint violation: loader (instance of %s)"
2018 " previously initiated loading for a different type with name \"%s\"";
2019 }
2020 }
2021 }
2022
2023 // Throw error now if needed (cannot throw while holding
2024 // SystemDictionary_lock because of rank ordering)
2025
2026 if (linkage_error) {
2027 ResourceMark rm(THREAD);
2028 const char* class_loader_name = loader_name(class_loader());
2029 char* type_name = k->name()->as_C_string();
2030 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2031 strlen(type_name);
2032 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2033 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2034 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2035 }
2036 }
2037
2038
2039 // Update system dictionary - done after check_constraint and add_to_hierachy
2040 // have been called.
2041 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2042 int p_index, unsigned int p_hash,
2043 instanceKlassHandle k,
2044 Handle class_loader,
2045 TRAPS) {
2046 // Compile_lock prevents systemDictionary updates during compilations
2047 assert_locked_or_safepoint(Compile_lock);
2048 symbolHandle name (THREAD, k->name());
2049
2050 {
2051 MutexLocker mu1(SystemDictionary_lock, THREAD);
2052
2053 // See whether biased locking is enabled and if so set it for this
2054 // klass.
2055 // Note that this must be done past the last potential blocking
2056 // point / safepoint. We enable biased locking lazily using a
2057 // VM_Operation to iterate the SystemDictionary and installing the
2058 // biasable mark word into each instanceKlass's prototype header.
2059 // To avoid race conditions where we accidentally miss enabling the
2060 // optimization for one class in the process of being added to the
2061 // dictionary, we must not safepoint after the test of
2062 // BiasedLocking::enabled().
2063 if (UseBiasedLocking && BiasedLocking::enabled()) {
2064 // Set biased locking bit for all loaded classes; it will be
2065 // cleared if revocation occurs too often for this type
2066 // NOTE that we must only do this when the class is initally
2067 // defined, not each time it is referenced from a new class loader
2068 if (k->class_loader() == class_loader()) {
2069 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2070 }
2071 }
2072
2073 // Check for a placeholder. If there, remove it and make a
2074 // new system dictionary entry.
2075 placeholders()->find_and_remove(p_index, p_hash, name, class_loader, THREAD);
2076 klassOop sd_check = find_class(d_index, d_hash, name, class_loader);
2077 if (sd_check == NULL) {
2078 dictionary()->add_klass(name, class_loader, k);
2079 notice_modification();
2080 }
2081 #ifdef ASSERT
2082 sd_check = find_class(d_index, d_hash, name, class_loader);
2083 assert (sd_check != NULL, "should have entry in system dictionary");
2084 // Changed to allow PH to remain to complete class circularity checking
2085 // while only one thread can define a class at one time, multiple
2086 // classes can resolve the superclass for a class at one time,
2087 // and the placeholder is used to track that
2088 // symbolOop ph_check = find_placeholder(p_index, p_hash, name, class_loader);
2089 // assert (ph_check == NULL, "should not have a placeholder entry");
2090 #endif
2091 SystemDictionary_lock->notify_all();
2092 }
2093 }
2094
2095
2096 klassOop SystemDictionary::find_constrained_instance_or_array_klass(
2097 symbolHandle class_name, Handle class_loader, TRAPS) {
2098
2099 // First see if it has been loaded directly.
2100 // Force the protection domain to be null. (This removes protection checks.)
2101 Handle no_protection_domain;
2102 klassOop klass = find_instance_or_array_klass(class_name, class_loader,
2103 no_protection_domain, CHECK_NULL);
2104 if (klass != NULL)
2105 return klass;
2106
2107 // Now look to see if it has been loaded elsewhere, and is subject to
2108 // a loader constraint that would require this loader to return the
2109 // klass that is already loaded.
2110 if (FieldType::is_array(class_name())) {
2111 // Array classes are hard because their klassOops are not kept in the
2112 // constraint table. The array klass may be constrained, but the elem class
2113 // may not be.
2114 jint dimension;
2115 symbolOop object_key;
2116 BasicType t = FieldType::get_array_info(class_name(), &dimension,
2117 &object_key, CHECK_(NULL));
2118 if (t != T_OBJECT) {
2119 klass = Universe::typeArrayKlassObj(t);
2120 } else {
2121 symbolHandle elem_name(THREAD, object_key);
2122 MutexLocker mu(SystemDictionary_lock, THREAD);
2123 klass = constraints()->find_constrained_elem_klass(class_name, elem_name, class_loader, THREAD);
2124 }
2125 if (klass != NULL) {
2126 klass = Klass::cast(klass)->array_klass_or_null(dimension);
2127 }
2128 } else {
2129 MutexLocker mu(SystemDictionary_lock, THREAD);
2130 // Non-array classes are easy: simply check the constraint table.
2131 klass = constraints()->find_constrained_klass(class_name, class_loader);
2132 }
2133
2134 return klass;
2135 }
2136
2137
2138 bool SystemDictionary::add_loader_constraint(symbolHandle class_name,
2139 Handle class_loader1,
2140 Handle class_loader2,
2141 Thread* THREAD) {
2142 unsigned int d_hash1 = dictionary()->compute_hash(class_name, class_loader1);
2143 int d_index1 = dictionary()->hash_to_index(d_hash1);
2144
2145 unsigned int d_hash2 = dictionary()->compute_hash(class_name, class_loader2);
2146 int d_index2 = dictionary()->hash_to_index(d_hash2);
2147
2148 {
2149 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2150
2151 // Better never do a GC while we're holding these oops
2152 No_Safepoint_Verifier nosafepoint;
2153
2154 klassOop klass1 = find_class(d_index1, d_hash1, class_name, class_loader1);
2155 klassOop klass2 = find_class(d_index2, d_hash2, class_name, class_loader2);
2156 return constraints()->add_entry(class_name, klass1, class_loader1,
2157 klass2, class_loader2);
2158 }
2159 }
2160
2161 // Add entry to resolution error table to record the error when the first
2162 // attempt to resolve a reference to a class has failed.
2163 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, symbolHandle error) {
2164 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2165 int index = resolution_errors()->hash_to_index(hash);
2166 {
2167 MutexLocker ml(SystemDictionary_lock, Thread::current());
2168 resolution_errors()->add_entry(index, hash, pool, which, error);
2169 }
2170 }
2171
2172 // Lookup resolution error table. Returns error if found, otherwise NULL.
2173 symbolOop SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2174 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2175 int index = resolution_errors()->hash_to_index(hash);
2176 {
2177 MutexLocker ml(SystemDictionary_lock, Thread::current());
2178 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2179 return (entry != NULL) ? entry->error() : (symbolOop)NULL;
2180 }
2181 }
2182
2183
2184 // Make sure all class components (including arrays) in the given
2185 // signature will be resolved to the same class in both loaders.
2186 // Returns the name of the type that failed a loader constraint check, or
2187 // NULL if no constraint failed. The returned C string needs cleaning up
2188 // with a ResourceMark in the caller
2189 char* SystemDictionary::check_signature_loaders(symbolHandle signature,
2190 Handle loader1, Handle loader2,
2191 bool is_method, TRAPS) {
2192 // Nothing to do if loaders are the same.
2193 if (loader1() == loader2()) {
2194 return NULL;
2195 }
2196
2197 SignatureStream sig_strm(signature, is_method);
2198 while (!sig_strm.is_done()) {
2199 if (sig_strm.is_object()) {
2200 symbolOop s = sig_strm.as_symbol(CHECK_NULL);
2201 symbolHandle sig (THREAD, s);
2202 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2203 return sig()->as_C_string();
2204 }
2205 }
2206 sig_strm.next();
2207 }
2208 return NULL;
2209 }
2210
2211
2212 // Since the identity hash code for symbols changes when the symbols are
2213 // moved from the regular perm gen (hash in the mark word) to the shared
2214 // spaces (hash is the address), the classes loaded into the dictionary
2215 // may be in the wrong buckets.
2216
2217 void SystemDictionary::reorder_dictionary() {
2218 dictionary()->reorder_dictionary();
2219 }
2220
2221
2222 void SystemDictionary::copy_buckets(char** top, char* end) {
2223 dictionary()->copy_buckets(top, end);
2224 }
2225
2226
2227 void SystemDictionary::copy_table(char** top, char* end) {
2228 dictionary()->copy_table(top, end);
2229 }
2230
2231
2232 void SystemDictionary::reverse() {
2233 dictionary()->reverse();
2234 }
2235
2236 int SystemDictionary::number_of_classes() {
2237 return dictionary()->number_of_entries();
2238 }
2239
2240
2241 // ----------------------------------------------------------------------------
2242 #ifndef PRODUCT
2243
2244 void SystemDictionary::print() {
2245 dictionary()->print();
2246
2247 // Placeholders
2248 GCMutexLocker mu(SystemDictionary_lock);
2249 placeholders()->print();
2250
2251 // loader constraints - print under SD_lock
2252 constraints()->print();
2253 }
2254
2255 #endif
2256
2257 void SystemDictionary::verify() {
2258 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2259 guarantee(constraints() != NULL,
2260 "Verify of loader constraints failed");
2261 guarantee(dictionary()->number_of_entries() >= 0 &&
2262 placeholders()->number_of_entries() >= 0,
2263 "Verify of system dictionary failed");
2264
2265 // Verify dictionary
2266 dictionary()->verify();
2267
2268 GCMutexLocker mu(SystemDictionary_lock);
2269 placeholders()->verify();
2270
2271 // Verify constraint table
2272 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2273 constraints()->verify(dictionary());
2274 }
2275
2276
2277 void SystemDictionary::verify_obj_klass_present(Handle obj,
2278 symbolHandle class_name,
2279 Handle class_loader) {
2280 GCMutexLocker mu(SystemDictionary_lock);
2281 oop probe = find_class_or_placeholder(class_name, class_loader);
2282 if (probe == NULL) {
2283 probe = SystemDictionary::find_shared_class(class_name);
2284 }
2285 guarantee(probe != NULL &&
2286 (!probe->is_klass() || probe == obj()),
2287 "Loaded klasses should be in SystemDictionary");
2288 }
2289
2290 #ifndef PRODUCT
2291
2292 // statistics code
2293 class ClassStatistics: AllStatic {
2294 private:
2295 static int nclasses; // number of classes
2296 static int nmethods; // number of methods
2297 static int nmethoddata; // number of methodData
2298 static int class_size; // size of class objects in words
2299 static int method_size; // size of method objects in words
2300 static int debug_size; // size of debug info in methods
2301 static int methoddata_size; // size of methodData objects in words
2302
2303 static void do_class(klassOop k) {
2304 nclasses++;
2305 class_size += k->size();
2306 if (k->klass_part()->oop_is_instance()) {
2307 instanceKlass* ik = (instanceKlass*)k->klass_part();
2308 class_size += ik->methods()->size();
2309 class_size += ik->constants()->size();
2310 class_size += ik->local_interfaces()->size();
2311 class_size += ik->transitive_interfaces()->size();
2312 // We do not have to count implementors, since we only store one!
2313 class_size += ik->fields()->size();
2314 }
2315 }
2316
2317 static void do_method(methodOop m) {
2318 nmethods++;
2319 method_size += m->size();
2320 // class loader uses same objArray for empty vectors, so don't count these
2321 if (m->exception_table()->length() != 0) method_size += m->exception_table()->size();
2322 if (m->has_stackmap_table()) {
2323 method_size += m->stackmap_data()->size();
2324 }
2325
2326 methodDataOop mdo = m->method_data();
2327 if (mdo != NULL) {
2328 nmethoddata++;
2329 methoddata_size += mdo->size();
2330 }
2331 }
2332
2333 public:
2334 static void print() {
2335 SystemDictionary::classes_do(do_class);
2336 SystemDictionary::methods_do(do_method);
2337 tty->print_cr("Class statistics:");
2338 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2339 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2340 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2341 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2342 }
2343 };
2344
2345
2346 int ClassStatistics::nclasses = 0;
2347 int ClassStatistics::nmethods = 0;
2348 int ClassStatistics::nmethoddata = 0;
2349 int ClassStatistics::class_size = 0;
2350 int ClassStatistics::method_size = 0;
2351 int ClassStatistics::debug_size = 0;
2352 int ClassStatistics::methoddata_size = 0;
2353
2354 void SystemDictionary::print_class_statistics() {
2355 ResourceMark rm;
2356 ClassStatistics::print();
2357 }
2358
2359
2360 class MethodStatistics: AllStatic {
2361 public:
2362 enum {
2363 max_parameter_size = 10
2364 };
2365 private:
2366
2367 static int _number_of_methods;
2368 static int _number_of_final_methods;
2369 static int _number_of_static_methods;
2370 static int _number_of_native_methods;
2371 static int _number_of_synchronized_methods;
2372 static int _number_of_profiled_methods;
2373 static int _number_of_bytecodes;
2374 static int _parameter_size_profile[max_parameter_size];
2375 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2376
2377 static void initialize() {
2378 _number_of_methods = 0;
2379 _number_of_final_methods = 0;
2380 _number_of_static_methods = 0;
2381 _number_of_native_methods = 0;
2382 _number_of_synchronized_methods = 0;
2383 _number_of_profiled_methods = 0;
2384 _number_of_bytecodes = 0;
2385 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2386 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2387 };
2388
2389 static void do_method(methodOop m) {
2390 _number_of_methods++;
2391 // collect flag info
2392 if (m->is_final() ) _number_of_final_methods++;
2393 if (m->is_static() ) _number_of_static_methods++;
2394 if (m->is_native() ) _number_of_native_methods++;
2395 if (m->is_synchronized()) _number_of_synchronized_methods++;
2396 if (m->method_data() != NULL) _number_of_profiled_methods++;
2397 // collect parameter size info (add one for receiver, if any)
2398 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2399 // collect bytecodes info
2400 {
2401 Thread *thread = Thread::current();
2402 HandleMark hm(thread);
2403 BytecodeStream s(methodHandle(thread, m));
2404 Bytecodes::Code c;
2405 while ((c = s.next()) >= 0) {
2406 _number_of_bytecodes++;
2407 _bytecodes_profile[c]++;
2408 }
2409 }
2410 }
2411
2412 public:
2413 static void print() {
2414 initialize();
2415 SystemDictionary::methods_do(do_method);
2416 // generate output
2417 tty->cr();
2418 tty->print_cr("Method statistics (static):");
2419 // flag distribution
2420 tty->cr();
2421 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2422 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2423 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2424 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2425 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2426 // parameter size profile
2427 tty->cr();
2428 { int tot = 0;
2429 int avg = 0;
2430 for (int i = 0; i < max_parameter_size; i++) {
2431 int n = _parameter_size_profile[i];
2432 tot += n;
2433 avg += n*i;
2434 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2435 }
2436 assert(tot == _number_of_methods, "should be the same");
2437 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2438 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2439 }
2440 // bytecodes profile
2441 tty->cr();
2442 { int tot = 0;
2443 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2444 if (Bytecodes::is_defined(i)) {
2445 Bytecodes::Code c = Bytecodes::cast(i);
2446 int n = _bytecodes_profile[c];
2447 tot += n;
2448 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2449 }
2450 }
2451 assert(tot == _number_of_bytecodes, "should be the same");
2452 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2453 }
2454 tty->cr();
2455 }
2456 };
2457
2458 int MethodStatistics::_number_of_methods;
2459 int MethodStatistics::_number_of_final_methods;
2460 int MethodStatistics::_number_of_static_methods;
2461 int MethodStatistics::_number_of_native_methods;
2462 int MethodStatistics::_number_of_synchronized_methods;
2463 int MethodStatistics::_number_of_profiled_methods;
2464 int MethodStatistics::_number_of_bytecodes;
2465 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2466 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2467
2468
2469 void SystemDictionary::print_method_statistics() {
2470 MethodStatistics::print();
2471 }
2472
2473 #endif // PRODUCT