1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/symbolTable.hpp"
44 #include "classfile/systemDictionary.hpp"
45 #include "classfile/vmSymbols.hpp"
46 #include "code/codeCache.hpp"
47 #include "compiler/compileBroker.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/oopStorage.inline.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "interpreter/bytecodeStream.hpp"
52 #include "interpreter/interpreter.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "logging/log.hpp"
55 #include "logging/logStream.hpp"
56 #include "memory/filemap.hpp"
57 #include "memory/heapShared.hpp"
58 #include "memory/metaspaceClosure.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/access.inline.hpp"
63 #include "oops/instanceKlass.hpp"
64 #include "oops/instanceRefKlass.hpp"
65 #include "oops/klass.inline.hpp"
66 #include "oops/method.inline.hpp"
67 #include "oops/methodData.hpp"
68 #include "oops/objArrayKlass.hpp"
69 #include "oops/objArrayOop.inline.hpp"
70 #include "oops/oop.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #if INCLUDE_CDS
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JFR
91 #include "jfr/jfr.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108 oop SystemDictionary::_java_platform_loader = NULL;
109
110 // Default ProtectionDomainCacheSize value
111
112 const int defaultProtectionDomainCacheSize = 1009;
113
114 // ----------------------------------------------------------------------------
115 // Java-level SystemLoader and PlatformLoader
116
117 oop SystemDictionary::java_system_loader() {
118 return _java_system_loader;
119 }
120
121 oop SystemDictionary::java_platform_loader() {
122 return _java_platform_loader;
123 }
124
125 void SystemDictionary::compute_java_loaders(TRAPS) {
126 JavaValue result(T_OBJECT);
127 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
128 JavaCalls::call_static(&result,
129 class_loader_klass,
130 vmSymbols::getSystemClassLoader_name(),
131 vmSymbols::void_classloader_signature(),
132 CHECK);
133
134 _java_system_loader = (oop)result.get_jobject();
135
136 JavaCalls::call_static(&result,
137 class_loader_klass,
138 vmSymbols::getPlatformClassLoader_name(),
139 vmSymbols::void_classloader_signature(),
140 CHECK);
141
142 _java_platform_loader = (oop)result.get_jobject();
143 }
144
145 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
146 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
147 return ClassLoaderDataGraph::find_or_create(class_loader);
148 }
149
150 // ----------------------------------------------------------------------------
151 // Parallel class loading check
152
153 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
154 if (class_loader.is_null()) return true;
155 if (AlwaysLockClassLoader) return false;
156 return java_lang_ClassLoader::parallelCapable(class_loader());
157 }
158 // ----------------------------------------------------------------------------
159 // ParallelDefineClass flag does not apply to bootclass loader
160 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
161 if (class_loader.is_null()) return false;
162 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
163 return true;
164 }
165 return false;
166 }
167
168 // Returns true if the passed class loader is the builtin application class loader
169 // or a custom system class loader. A customer system class loader can be
170 // specified via -Djava.system.class.loader.
171 bool SystemDictionary::is_system_class_loader(oop class_loader) {
172 if (class_loader == NULL) {
173 return false;
174 }
175 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
176 class_loader == _java_system_loader);
177 }
178
179 // Returns true if the passed class loader is the platform class loader.
180 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
185 }
186
187 // ----------------------------------------------------------------------------
188 // Resolving of classes
189
190 // Forwards to resolve_or_null
191
192 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
193 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
194 if (HAS_PENDING_EXCEPTION || klass == NULL) {
195 // can return a null klass
196 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
197 }
198 return klass;
199 }
200
201 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
202 bool throw_error,
203 Klass* klass, TRAPS) {
204 if (HAS_PENDING_EXCEPTION) {
205 // If we have a pending exception we forward it to the caller, unless throw_error is true,
206 // in which case we have to check whether the pending exception is a ClassNotFoundException,
207 // and if so convert it to a NoClassDefFoundError
208 // And chain the original ClassNotFoundException
209 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
210 ResourceMark rm(THREAD);
211 assert(klass == NULL, "Should not have result with exception pending");
212 Handle e(THREAD, PENDING_EXCEPTION);
213 CLEAR_PENDING_EXCEPTION;
214 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
215 } else {
216 return NULL;
217 }
218 }
219 // Class not found, throw appropriate error or exception depending on value of throw_error
220 if (klass == NULL) {
221 ResourceMark rm(THREAD);
222 if (throw_error) {
223 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
224 } else {
225 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
226 }
227 }
228 return klass;
229 }
230
231
232 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
233 bool throw_error, TRAPS)
234 {
235 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
236 }
237
238
239 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
240
241 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
242 if (Signature::is_array(class_name)) {
243 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
244 } else {
245 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
246 }
247 }
248
249 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
250 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
251 Handle class_loader,
252 Handle protection_domain,
253 TRAPS) {
254 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
255 if (Signature::has_envelope(class_name)) {
256 ResourceMark rm(THREAD);
257 // Ignore wrapping L and ;.
258 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
259 class_name->utf8_length() - 2);
260 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
261 } else {
262 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
263 }
264 }
265
266 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
267 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
268 }
269
270 // Forwards to resolve_instance_class_or_null
271
272 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
273 Handle class_loader,
274 Handle protection_domain,
275 TRAPS) {
276 assert(Signature::is_array(class_name), "must be array");
277 ResourceMark rm(THREAD);
278 SignatureStream ss(class_name, false);
279 int ndims = ss.skip_array_prefix(); // skip all '['s
280 Klass* k = NULL;
281 BasicType t = ss.type();
282 if (ss.has_envelope()) {
283 Symbol* obj_class = ss.as_symbol();
284 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
285 class_loader,
286 protection_domain,
287 CHECK_NULL);
288 if (k != NULL) {
289 k = k->array_klass(ndims, CHECK_NULL);
290 }
291 } else {
292 k = Universe::typeArrayKlassObj(t);
293 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
294 }
295 return k;
296 }
297
298
299 // Must be called for any super-class or super-interface resolution
300 // during class definition to allow class circularity checking
301 // super-interface callers:
302 // parse_interfaces - for defineClass & jvmtiRedefineClasses
303 // super-class callers:
304 // ClassFileParser - for defineClass & jvmtiRedefineClasses
305 // load_shared_class - while loading a class from shared archive
306 // resolve_instance_class_or_null:
307 // via: handle_parallel_super_load
308 // when resolving a class that has an existing placeholder with
309 // a saved superclass [i.e. a defineClass is currently in progress]
310 // if another thread is trying to resolve the class, it must do
311 // super-class checks on its own thread to catch class circularity
312 // This last call is critical in class circularity checking for cases
313 // where classloading is delegated to different threads and the
314 // classloader lock is released.
315 // Take the case: Base->Super->Base
316 // 1. If thread T1 tries to do a defineClass of class Base
317 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
318 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
319 // so it tries to load Super
320 // 3. If we load the class internally, or user classloader uses same thread
321 // loadClassFromxxx or defineClass via parseClassFile Super ...
322 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
323 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
324 // 3.4 calls resolve_super_or_fail Base
325 // 3.5 finds T1,Base -> throws class circularity
326 //OR 4. If T2 tries to resolve Super via defineClass Super ...
327 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
328 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
329 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
330 // 4.4 finds T2, Super -> throws class circularity
331 // Must be called, even if superclass is null, since this is
332 // where the placeholder entry is created which claims this
333 // thread is loading this class/classloader.
334 // Be careful when modifying this code: once you have run
335 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
336 // you need to find_and_remove it before returning.
337 // So be careful to not exit with a CHECK_ macro betweeen these calls.
338 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
339 Symbol* super_name,
340 Handle class_loader,
341 Handle protection_domain,
342 bool is_superclass,
343 TRAPS) {
344 assert(!Signature::is_array(super_name), "invalid super class name");
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for handling UNREGISTERED shared classes.
348 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(THREAD, SystemDictionary_lock);
381 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
382 InstanceKlass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if super_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->java_super()) != NULL) &&
391 ((quicksuperk->name() == super_name) &&
392 (quicksuperk->class_loader() == class_loader()))) {
393 return quicksuperk;
394 } else {
395 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
396 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
397 throw_circularity_error = true;
398 }
399 }
400 if (!throw_circularity_error) {
401 // Be careful not to exit resolve_super
402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
403 }
404 }
405 if (throw_circularity_error) {
406 ResourceMark rm(THREAD);
407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
408 }
409
410 // java.lang.Object should have been found above
411 assert(super_name != NULL, "null super class for resolving");
412 // Resolve the super class or interface, check results on return
413 InstanceKlass* superk =
414 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(THREAD, SystemDictionary_lock);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
433 assert(k == NULL || k == superk, "must be");
434 if (k == NULL) {
435 superk = NULL;
436 }
437 }
438
439 return superk;
440 }
441
442 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
443 Handle class_loader,
444 Handle protection_domain,
445 TRAPS) {
446 // Now we have to call back to java to check if the initating class has access
447 JavaValue result(T_VOID);
448 LogTarget(Debug, protectiondomain) lt;
449 if (lt.is_enabled()) {
450 ResourceMark rm(THREAD);
451 // Print out trace information
452 LogStream ls(lt);
453 ls.print_cr("Checking package access");
454 if (class_loader() != NULL) {
455 ls.print("class loader: ");
456 class_loader()->print_value_on(&ls);
457 } else {
458 ls.print_cr("class loader: NULL");
459 }
460 if (protection_domain() != NULL) {
461 ls.print(" protection domain: ");
462 protection_domain()->print_value_on(&ls);
463 } else {
464 ls.print_cr(" protection domain: NULL");
465 }
466 ls.print(" loading: "); klass->print_value_on(&ls);
467 ls.cr();
468 }
469
470 // This handle and the class_loader handle passed in keeps this class from
471 // being unloaded through several GC points.
472 // The class_loader handle passed in is the initiating loader.
473 Handle mirror(THREAD, klass->java_mirror());
474
475 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
476 JavaCalls::call_special(&result,
477 class_loader,
478 system_loader,
479 vmSymbols::checkPackageAccess_name(),
480 vmSymbols::class_protectiondomain_signature(),
481 mirror,
482 protection_domain,
483 THREAD);
484
485 if (HAS_PENDING_EXCEPTION) {
486 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
487 } else {
488 log_debug(protectiondomain)("granted");
489 }
490
491 if (HAS_PENDING_EXCEPTION) return;
492
493 // If no exception has been thrown, we have validated the protection domain
494 // Insert the protection domain of the initiating class into the set.
495 {
496 ClassLoaderData* loader_data = class_loader_data(class_loader);
497 Dictionary* dictionary = loader_data->dictionary();
498
499 Symbol* kn = klass->name();
500 unsigned int d_hash = dictionary->compute_hash(kn);
501
502 MutexLocker mu(THREAD, SystemDictionary_lock);
503 int d_index = dictionary->hash_to_index(d_hash);
504 dictionary->add_protection_domain(d_index, d_hash, klass,
505 protection_domain, THREAD);
506 }
507 }
508
509 // We only get here if this thread finds that another thread
510 // has already claimed the placeholder token for the current operation,
511 // but that other thread either never owned or gave up the
512 // object lock
513 // Waits on SystemDictionary_lock to indicate placeholder table updated
514 // On return, caller must recheck placeholder table state
515 //
516 // We only get here if
517 // 1) custom classLoader, i.e. not bootstrap classloader
518 // 2) custom classLoader has broken the class loader objectLock
519 // so another thread got here in parallel
520 //
521 // lockObject must be held.
522 // Complicated dance due to lock ordering:
523 // Must first release the classloader object lock to
524 // allow initial definer to complete the class definition
525 // and to avoid deadlock
526 // Reclaim classloader lock object with same original recursion count
527 // Must release SystemDictionary_lock after notify, since
528 // class loader lock must be claimed before SystemDictionary_lock
529 // to prevent deadlocks
530 //
531 // The notify allows applications that did an untimed wait() on
532 // the classloader object lock to not hang.
533 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
534 assert_lock_strong(SystemDictionary_lock);
535
536 bool calledholdinglock
537 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
538 assert(calledholdinglock,"must hold lock for notify");
539 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
540 ObjectSynchronizer::notifyall(lockObject, THREAD);
541
542 TSAN_ONLY(int tsan_rec = 0;)
543 TSAN_RUNTIME_ONLY(
544 tsan_rec = SharedRuntime::tsan_oop_rec_unlock(THREAD, lockObject());
545 assert(tsan_rec > 0, "tsan: unlocking unlocked mutex");
546 );
547 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
548 SystemDictionary_lock->wait();
549 SystemDictionary_lock->unlock();
550 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
551 TSAN_RUNTIME_ONLY(SharedRuntime::tsan_oop_rec_lock(THREAD, lockObject(), tsan_rec));
552 SystemDictionary_lock->lock();
553 }
554
555 // If the class in is in the placeholder table, class loading is in progress
556 // For cases where the application changes threads to load classes, it
557 // is critical to ClassCircularity detection that we try loading
558 // the superclass on the same thread internally, so we do parallel
559 // super class loading here.
560 // This also is critical in cases where the original thread gets stalled
561 // even in non-circularity situations.
562 // Note: must call resolve_super_or_fail even if null super -
563 // to force placeholder entry creation for this class for circularity detection
564 // Caller must check for pending exception
565 // Returns non-null Klass* if other thread has completed load
566 // and we are done,
567 // If return null Klass* and no pending exception, the caller must load the class
568 InstanceKlass* SystemDictionary::handle_parallel_super_load(
569 Symbol* name, Symbol* superclassname, Handle class_loader,
570 Handle protection_domain, Handle lockObject, TRAPS) {
571
572 ClassLoaderData* loader_data = class_loader_data(class_loader);
573 Dictionary* dictionary = loader_data->dictionary();
574 unsigned int d_hash = dictionary->compute_hash(name);
575 unsigned int p_hash = placeholders()->compute_hash(name);
576 int p_index = placeholders()->hash_to_index(p_hash);
577
578 // superk is not used, resolve_super called for circularity check only
579 // This code is reached in two situations. One if this thread
580 // is loading the same class twice (e.g. ClassCircularity, or
581 // java.lang.instrument).
582 // The second is if another thread started the resolve_super first
583 // and has not yet finished.
584 // In both cases the original caller will clean up the placeholder
585 // entry on error.
586 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
587 superclassname,
588 class_loader,
589 protection_domain,
590 true,
591 CHECK_NULL);
592
593 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
594 // Serial class loaders and bootstrap classloader do wait for superclass loads
595 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
596 MutexLocker mu(THREAD, SystemDictionary_lock);
597 // Check if classloading completed while we were loading superclass or waiting
598 return find_class(d_hash, name, dictionary);
599 }
600
601 // must loop to both handle other placeholder updates
602 // and spurious notifications
603 bool super_load_in_progress = true;
604 PlaceholderEntry* placeholder;
605 while (super_load_in_progress) {
606 MutexLocker mu(THREAD, SystemDictionary_lock);
607 // Check if classloading completed while we were loading superclass or waiting
608 InstanceKlass* check = find_class(d_hash, name, dictionary);
609 if (check != NULL) {
610 // Klass is already loaded, so just return it
611 return check;
612 } else {
613 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
614 if (placeholder && placeholder->super_load_in_progress() ){
615 // We only get here if the application has released the
616 // classloader lock when another thread was in the middle of loading a
617 // superclass/superinterface for this class, and now
618 // this thread is also trying to load this class.
619 // To minimize surprises, the first thread that started to
620 // load a class should be the one to complete the loading
621 // with the classfile it initially expected.
622 // This logic has the current thread wait once it has done
623 // all the superclass/superinterface loading it can, until
624 // the original thread completes the class loading or fails
625 // If it completes we will use the resulting InstanceKlass
626 // which we will find below in the systemDictionary.
627 // We also get here for parallel bootstrap classloader
628 if (class_loader.is_null()) {
629 SystemDictionary_lock->wait();
630 } else {
631 double_lock_wait(lockObject, THREAD);
632 }
633 } else {
634 // If not in SD and not in PH, other thread's load must have failed
635 super_load_in_progress = false;
636 }
637 }
638 }
639 return NULL;
640 }
641
642 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
643 assert(event != NULL, "invariant");
644 assert(k != NULL, "invariant");
645 assert(event->should_commit(), "invariant");
646 event->set_loadedClass(k);
647 event->set_definingClassLoader(k->class_loader_data());
648 event->set_initiatingClassLoader(init_cld);
649 event->commit();
650 }
651
652
653 // Be careful when modifying this code: once you have run
654 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
655 // you need to find_and_remove it before returning.
656 // So be careful to not exit with a CHECK_ macro betweeen these calls.
657 //
658 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
659 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
660 Handle class_loader,
661 Handle protection_domain,
662 TRAPS) {
663 assert(name != NULL && !Signature::is_array(name) &&
664 !Signature::has_envelope(name), "invalid class name");
665
666 EventClassLoad class_load_start_event;
667
668 HandleMark hm(THREAD);
669
670 // Fix for 4474172; see evaluation for more details
671 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
672 ClassLoaderData* loader_data = register_loader(class_loader);
673 Dictionary* dictionary = loader_data->dictionary();
674 unsigned int d_hash = dictionary->compute_hash(name);
675
676 // Do lookup to see if class already exist and the protection domain
677 // has the right access
678 // This call uses find which checks protection domain already matches
679 // All subsequent calls use find_class, and set has_loaded_class so that
680 // before we return a result we call out to java to check for valid protection domain
681 // to allow returning the Klass* and add it to the pd_set if it is valid
682 {
683 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
684 if (probe != NULL) return probe;
685 }
686
687 // Non-bootstrap class loaders will call out to class loader and
688 // define via jvm/jni_DefineClass which will acquire the
689 // class loader object lock to protect against multiple threads
690 // defining the class in parallel by accident.
691 // This lock must be acquired here so the waiter will find
692 // any successful result in the SystemDictionary and not attempt
693 // the define.
694 // ParallelCapable Classloaders and the bootstrap classloader
695 // do not acquire lock here.
696 bool DoObjectLock = true;
697 if (is_parallelCapable(class_loader)) {
698 DoObjectLock = false;
699 }
700
701 unsigned int p_hash = placeholders()->compute_hash(name);
702 int p_index = placeholders()->hash_to_index(p_hash);
703
704 // Class is not in SystemDictionary so we have to do loading.
705 // Make sure we are synchronized on the class loader before we proceed
706 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
707 check_loader_lock_contention(lockObject, THREAD);
708 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
709
710 // Check again (after locking) if class already exist in SystemDictionary
711 bool class_has_been_loaded = false;
712 bool super_load_in_progress = false;
713 bool havesupername = false;
714 InstanceKlass* k = NULL;
715 PlaceholderEntry* placeholder;
716 Symbol* superclassname = NULL;
717
718 assert(THREAD->can_call_java(),
719 "can not load classes with compiler thread: class=%s, classloader=%s",
720 name->as_C_string(),
721 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
722 {
723 MutexLocker mu(THREAD, SystemDictionary_lock);
724 InstanceKlass* check = find_class(d_hash, name, dictionary);
725 if (check != NULL) {
726 // InstanceKlass is already loaded, so just return it
727 class_has_been_loaded = true;
728 k = check;
729 } else {
730 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
731 if (placeholder && placeholder->super_load_in_progress()) {
732 super_load_in_progress = true;
733 if (placeholder->havesupername() == true) {
734 superclassname = placeholder->supername();
735 havesupername = true;
736 }
737 }
738 }
739 }
740
741 // If the class is in the placeholder table, class loading is in progress
742 if (super_load_in_progress && havesupername==true) {
743 k = handle_parallel_super_load(name,
744 superclassname,
745 class_loader,
746 protection_domain,
747 lockObject, THREAD);
748 if (HAS_PENDING_EXCEPTION) {
749 return NULL;
750 }
751 if (k != NULL) {
752 class_has_been_loaded = true;
753 }
754 }
755
756 bool throw_circularity_error = false;
757 if (!class_has_been_loaded) {
758 bool load_instance_added = false;
759
760 // add placeholder entry to record loading instance class
761 // Five cases:
762 // All cases need to prevent modifying bootclasssearchpath
763 // in parallel with a classload of same classname
764 // Redefineclasses uses existence of the placeholder for the duration
765 // of the class load to prevent concurrent redefinition of not completely
766 // defined classes.
767 // case 1. traditional classloaders that rely on the classloader object lock
768 // - no other need for LOAD_INSTANCE
769 // case 2. traditional classloaders that break the classloader object lock
770 // as a deadlock workaround. Detection of this case requires that
771 // this check is done while holding the classloader object lock,
772 // and that lock is still held when calling classloader's loadClass.
773 // For these classloaders, we ensure that the first requestor
774 // completes the load and other requestors wait for completion.
775 // case 3. Bootstrap classloader - don't own objectLocker
776 // This classloader supports parallelism at the classloader level,
777 // but only allows a single load of a class/classloader pair.
778 // No performance benefit and no deadlock issues.
779 // case 4. parallelCapable user level classloaders - without objectLocker
780 // Allow parallel classloading of a class/classloader pair
781
782 {
783 MutexLocker mu(THREAD, SystemDictionary_lock);
784 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
785 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
786 if (oldprobe) {
787 // only need check_seen_thread once, not on each loop
788 // 6341374 java/lang/Instrument with -Xcomp
789 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
790 throw_circularity_error = true;
791 } else {
792 // case 1: traditional: should never see load_in_progress.
793 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
794
795 // case 3: bootstrap classloader: prevent futile classloading,
796 // wait on first requestor
797 if (class_loader.is_null()) {
798 SystemDictionary_lock->wait();
799 } else {
800 // case 2: traditional with broken classloader lock. wait on first
801 // requestor.
802 double_lock_wait(lockObject, THREAD);
803 }
804 // Check if classloading completed while we were waiting
805 InstanceKlass* check = find_class(d_hash, name, dictionary);
806 if (check != NULL) {
807 // Klass is already loaded, so just return it
808 k = check;
809 class_has_been_loaded = true;
810 }
811 // check if other thread failed to load and cleaned up
812 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
813 }
814 }
815 }
816 }
817 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
818 // case 4: parallelCapable: allow competing threads to try
819 // LOAD_INSTANCE in parallel
820
821 if (!throw_circularity_error && !class_has_been_loaded) {
822 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
823 load_instance_added = true;
824 // For class loaders that do not acquire the classloader object lock,
825 // if they did not catch another thread holding LOAD_INSTANCE,
826 // need a check analogous to the acquire ObjectLocker/find_class
827 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
828 // one final check if the load has already completed
829 // class loaders holding the ObjectLock shouldn't find the class here
830 InstanceKlass* check = find_class(d_hash, name, dictionary);
831 if (check != NULL) {
832 // Klass is already loaded, so return it after checking/adding protection domain
833 k = check;
834 class_has_been_loaded = true;
835 }
836 }
837 }
838
839 // must throw error outside of owning lock
840 if (throw_circularity_error) {
841 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
842 ResourceMark rm(THREAD);
843 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
844 }
845
846 if (!class_has_been_loaded) {
847
848 // Do actual loading
849 k = load_instance_class(name, class_loader, THREAD);
850
851 // If everything was OK (no exceptions, no null return value), and
852 // class_loader is NOT the defining loader, do a little more bookkeeping.
853 if (!HAS_PENDING_EXCEPTION && k != NULL &&
854 k->class_loader() != class_loader()) {
855
856 check_constraints(d_hash, k, class_loader, false, THREAD);
857
858 // Need to check for a PENDING_EXCEPTION again; check_constraints
859 // can throw but we may have to remove entry from the placeholder table below.
860 if (!HAS_PENDING_EXCEPTION) {
861 // Record dependency for non-parent delegation.
862 // This recording keeps the defining class loader of the klass (k) found
863 // from being unloaded while the initiating class loader is loaded
864 // even if the reference to the defining class loader is dropped
865 // before references to the initiating class loader.
866 loader_data->record_dependency(k);
867
868 { // Grabbing the Compile_lock prevents systemDictionary updates
869 // during compilations.
870 MutexLocker mu(THREAD, Compile_lock);
871 update_dictionary(d_hash, p_index, p_hash,
872 k, class_loader, THREAD);
873 }
874
875 if (JvmtiExport::should_post_class_load()) {
876 Thread *thread = THREAD;
877 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
878 JvmtiExport::post_class_load((JavaThread *) thread, k);
879 }
880 }
881 }
882 } // load_instance_class
883
884 if (load_instance_added == true) {
885 // clean up placeholder entries for LOAD_INSTANCE success or error
886 // This brackets the SystemDictionary updates for both defining
887 // and initiating loaders
888 MutexLocker mu(THREAD, SystemDictionary_lock);
889 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
890 SystemDictionary_lock->notify_all();
891 }
892 }
893
894 if (HAS_PENDING_EXCEPTION || k == NULL) {
895 return NULL;
896 }
897 if (class_load_start_event.should_commit()) {
898 post_class_load_event(&class_load_start_event, k, loader_data);
899 }
900 #ifdef ASSERT
901 {
902 ClassLoaderData* loader_data = k->class_loader_data();
903 MutexLocker mu(THREAD, SystemDictionary_lock);
904 InstanceKlass* kk = find_class(name, loader_data);
905 assert(kk == k, "should be present in dictionary");
906 }
907 #endif
908
909 // return if the protection domain in NULL
910 if (protection_domain() == NULL) return k;
911
912 // Check the protection domain has the right access
913 if (dictionary->is_valid_protection_domain(d_hash, name,
914 protection_domain)) {
915 return k;
916 }
917
918 // Verify protection domain. If it fails an exception is thrown
919 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
920
921 return k;
922 }
923
924
925 // This routine does not lock the system dictionary.
926 //
927 // Since readers don't hold a lock, we must make sure that system
928 // dictionary entries are only removed at a safepoint (when only one
929 // thread is running), and are added to in a safe way (all links must
930 // be updated in an MT-safe manner).
931 //
932 // Callers should be aware that an entry could be added just after
933 // _dictionary->bucket(index) is read here, so the caller will not see
934 // the new entry.
935
936 Klass* SystemDictionary::find(Symbol* class_name,
937 Handle class_loader,
938 Handle protection_domain,
939 TRAPS) {
940
941 // The result of this call should be consistent with the result
942 // of the call to resolve_instance_class_or_null().
943 // See evaluation 6790209 and 4474172 for more details.
944 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
945 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
946
947 if (loader_data == NULL) {
948 // If the ClassLoaderData has not been setup,
949 // then the class loader has no entries in the dictionary.
950 return NULL;
951 }
952
953 Dictionary* dictionary = loader_data->dictionary();
954 unsigned int d_hash = dictionary->compute_hash(class_name);
955 return dictionary->find(d_hash, class_name,
956 protection_domain);
957 }
958
959
960 // Look for a loaded instance or array klass by name. Do not do any loading.
961 // return NULL in case of error.
962 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
963 Handle class_loader,
964 Handle protection_domain,
965 TRAPS) {
966 Klass* k = NULL;
967 assert(class_name != NULL, "class name must be non NULL");
968
969 if (Signature::is_array(class_name)) {
970 // The name refers to an array. Parse the name.
971 // dimension and object_key in FieldArrayInfo are assigned as a
972 // side-effect of this call
973 SignatureStream ss(class_name, false);
974 int ndims = ss.skip_array_prefix(); // skip all '['s
975 BasicType t = ss.type();
976 if (t != T_OBJECT) {
977 k = Universe::typeArrayKlassObj(t);
978 } else {
979 Symbol* obj_class = ss.as_symbol();
980 k = SystemDictionary::find(obj_class, class_loader, protection_domain, THREAD);
981 }
982 if (k != NULL) {
983 k = k->array_klass_or_null(ndims);
984 }
985 } else {
986 k = find(class_name, class_loader, protection_domain, THREAD);
987 }
988 return k;
989 }
990
991 // Note: this method is much like resolve_from_stream, but
992 // does not publish the classes via the SystemDictionary.
993 // Handles unsafe_DefineAnonymousClass and redefineclasses
994 // RedefinedClasses do not add to the class hierarchy
995 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
996 Handle class_loader,
997 Handle protection_domain,
998 ClassFileStream* st,
999 const InstanceKlass* unsafe_anonymous_host,
1000 GrowableArray<Handle>* cp_patches,
1001 TRAPS) {
1002
1003 EventClassLoad class_load_start_event;
1004
1005 ClassLoaderData* loader_data;
1006 if (unsafe_anonymous_host != NULL) {
1007 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1008 // as the unsafe_anonymous_host
1009 guarantee(unsafe_anonymous_host->class_loader() == class_loader(), "should be the same");
1010 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1011 } else {
1012 loader_data = ClassLoaderData::class_loader_data(class_loader());
1013 }
1014
1015 assert(st != NULL, "invariant");
1016 assert(st->need_verify(), "invariant");
1017
1018 // Parse stream and create a klass.
1019 // Note that we do this even though this klass might
1020 // already be present in the SystemDictionary, otherwise we would not
1021 // throw potential ClassFormatErrors.
1022
1023 InstanceKlass* k = KlassFactory::create_from_stream(st,
1024 class_name,
1025 loader_data,
1026 protection_domain,
1027 unsafe_anonymous_host,
1028 cp_patches,
1029 CHECK_NULL);
1030
1031 if (unsafe_anonymous_host != NULL && k != NULL) {
1032 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1033 // so that they can be unloaded when the mirror is no longer referenced.
1034 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1035
1036 {
1037 MutexLocker mu_r(THREAD, Compile_lock);
1038
1039 // Add to class hierarchy, initialize vtables, and do possible
1040 // deoptimizations.
1041 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1042 // But, do not add to dictionary.
1043 }
1044
1045 // Rewrite and patch constant pool here.
1046 k->link_class(CHECK_NULL);
1047 if (cp_patches != NULL) {
1048 k->constants()->patch_resolved_references(cp_patches);
1049 }
1050
1051 // If it's anonymous, initialize it now, since nobody else will.
1052 k->eager_initialize(CHECK_NULL);
1053
1054 // notify jvmti
1055 if (JvmtiExport::should_post_class_load()) {
1056 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1057 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1058 }
1059 if (class_load_start_event.should_commit()) {
1060 post_class_load_event(&class_load_start_event, k, loader_data);
1061 }
1062 }
1063 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1064 "cp_patches only found with unsafe_anonymous_host");
1065
1066 return k;
1067 }
1068
1069 // Add a klass to the system from a stream (called by jni_DefineClass and
1070 // JVM_DefineClass).
1071 // Note: class_name can be NULL. In that case we do not know the name of
1072 // the class until we have parsed the stream.
1073
1074 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1075 Handle class_loader,
1076 Handle protection_domain,
1077 ClassFileStream* st,
1078 TRAPS) {
1079
1080 HandleMark hm(THREAD);
1081
1082 // Classloaders that support parallelism, e.g. bootstrap classloader,
1083 // do not acquire lock here
1084 bool DoObjectLock = true;
1085 if (is_parallelCapable(class_loader)) {
1086 DoObjectLock = false;
1087 }
1088
1089 ClassLoaderData* loader_data = register_loader(class_loader);
1090
1091 // Make sure we are synchronized on the class loader before we proceed
1092 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1093 check_loader_lock_contention(lockObject, THREAD);
1094 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1095
1096 assert(st != NULL, "invariant");
1097
1098 // Parse the stream and create a klass.
1099 // Note that we do this even though this klass might
1100 // already be present in the SystemDictionary, otherwise we would not
1101 // throw potential ClassFormatErrors.
1102 InstanceKlass* k = NULL;
1103
1104 #if INCLUDE_CDS
1105 if (!DumpSharedSpaces) {
1106 k = SystemDictionaryShared::lookup_from_stream(class_name,
1107 class_loader,
1108 protection_domain,
1109 st,
1110 CHECK_NULL);
1111 }
1112 #endif
1113
1114 if (k == NULL) {
1115 if (st->buffer() == NULL) {
1116 return NULL;
1117 }
1118 k = KlassFactory::create_from_stream(st,
1119 class_name,
1120 loader_data,
1121 protection_domain,
1122 NULL, // unsafe_anonymous_host
1123 NULL, // cp_patches
1124 CHECK_NULL);
1125 }
1126
1127 assert(k != NULL, "no klass created");
1128 Symbol* h_name = k->name();
1129 assert(class_name == NULL || class_name == h_name, "name mismatch");
1130
1131 // Add class just loaded
1132 // If a class loader supports parallel classloading handle parallel define requests
1133 // find_or_define_instance_class may return a different InstanceKlass
1134 if (is_parallelCapable(class_loader)) {
1135 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1136 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1137 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1138 assert(defined_k != NULL, "Should have a klass if there's no exception");
1139 loader_data->add_to_deallocate_list(k);
1140 k = defined_k;
1141 }
1142 } else {
1143 define_instance_class(k, THREAD);
1144 }
1145
1146 // If defining the class throws an exception register 'k' for cleanup.
1147 if (HAS_PENDING_EXCEPTION) {
1148 assert(k != NULL, "Must have an instance klass here!");
1149 loader_data->add_to_deallocate_list(k);
1150 return NULL;
1151 }
1152
1153 // Make sure we have an entry in the SystemDictionary on success
1154 debug_only( {
1155 MutexLocker mu(THREAD, SystemDictionary_lock);
1156
1157 Klass* check = find_class(h_name, k->class_loader_data());
1158 assert(check == k, "should be present in the dictionary");
1159 } );
1160
1161 return k;
1162 }
1163
1164 #if INCLUDE_CDS
1165 // Load a class for boot loader from the shared spaces. This also
1166 // forces the super class and all interfaces to be loaded.
1167 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1168 TRAPS) {
1169 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1170 if (ik != NULL && ik->is_shared_boot_class()) {
1171 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1172 }
1173 return NULL;
1174 }
1175
1176 // Check if a shared class can be loaded by the specific classloader:
1177 //
1178 // NULL classloader:
1179 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1180 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1181 // be defined in an unnamed module.
1182 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1183 InstanceKlass* ik,
1184 Handle class_loader, TRAPS) {
1185 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1186 "Cannot use sharing if java.base is patched");
1187 ResourceMark rm(THREAD);
1188 int path_index = ik->shared_classpath_index();
1189 ClassLoaderData* loader_data = class_loader_data(class_loader);
1190 if (path_index < 0) {
1191 // path_index < 0 indicates that the class is intended for a custom loader
1192 // and should not be loaded by boot/platform/app loaders
1193 if (loader_data->is_builtin_class_loader_data()) {
1194 return false;
1195 } else {
1196 return true;
1197 }
1198 }
1199 SharedClassPathEntry* ent =
1200 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1201 if (!Universe::is_module_initialized()) {
1202 assert(ent != NULL && ent->is_modules_image(),
1203 "Loading non-bootstrap classes before the module system is initialized");
1204 assert(class_loader.is_null(), "sanity");
1205 return true;
1206 }
1207 // Get the pkg_entry from the classloader
1208 TempNewSymbol pkg_name = NULL;
1209 PackageEntry* pkg_entry = NULL;
1210 ModuleEntry* mod_entry = NULL;
1211 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1212 if (pkg_name != NULL) {
1213 if (loader_data != NULL) {
1214 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1215 }
1216 if (pkg_entry != NULL) {
1217 mod_entry = pkg_entry->module();
1218 }
1219 }
1220
1221 // If the archived class is from a module that has been patched at runtime,
1222 // the class cannot be loaded from the archive.
1223 if (mod_entry != NULL && mod_entry->is_patched()) {
1224 return false;
1225 }
1226
1227 if (class_loader.is_null()) {
1228 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1229 // The NULL classloader can load archived class originated from the
1230 // "modules" jimage and the -Xbootclasspath/a. For class from the
1231 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1232 // by the NULL classloader.
1233 if (mod_entry != NULL) {
1234 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1235 // ModuleEntry's location agrees with the archived class' origination.
1236 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1237 return true; // Module class from the "module" jimage
1238 }
1239 }
1240
1241 // If the archived class is not from the "module" jimage, the class can be
1242 // loaded by the NULL classloader if
1243 //
1244 // 1. the class is from the unamed package
1245 // 2. or, the class is not from a module defined in the NULL classloader
1246 // 3. or, the class is from an unamed module
1247 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1248 // the class is from the -Xbootclasspath/a
1249 if (pkg_name == NULL ||
1250 pkg_entry == NULL ||
1251 pkg_entry->in_unnamed_module()) {
1252 assert(mod_entry == NULL ||
1253 mod_entry == loader_data->unnamed_module(),
1254 "the unnamed module is not defined in the classloader");
1255 return true;
1256 }
1257 }
1258 return false;
1259 } else {
1260 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1261 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1262 return res;
1263 }
1264 }
1265
1266 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1267 Handle class_loader,
1268 Handle protection_domain,
1269 const ClassFileStream *cfs,
1270 TRAPS) {
1271 assert(ik != NULL, "sanity");
1272 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1273 Symbol* class_name = ik->name();
1274
1275 bool visible = is_shared_class_visible(
1276 class_name, ik, class_loader, CHECK_NULL);
1277 if (!visible) {
1278 return NULL;
1279 }
1280
1281 // Resolve the superclass and interfaces. They must be the same
1282 // as in dump time, because the layout of <ik> depends on
1283 // the specific layout of ik->super() and ik->local_interfaces().
1284 //
1285 // If unexpected superclass or interfaces are found, we cannot
1286 // load <ik> from the shared archive.
1287
1288 if (ik->super() != NULL) {
1289 Symbol* cn = ik->super()->name();
1290 Klass *s = resolve_super_or_fail(class_name, cn,
1291 class_loader, protection_domain, true, CHECK_NULL);
1292 if (s != ik->super()) {
1293 // The dynamically resolved super class is not the same as the one we used during dump time,
1294 // so we cannot use ik.
1295 return NULL;
1296 } else {
1297 assert(s->is_shared(), "must be");
1298 }
1299 }
1300
1301 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1302 int num_interfaces = interfaces->length();
1303 for (int index = 0; index < num_interfaces; index++) {
1304 InstanceKlass* k = interfaces->at(index);
1305 Symbol* name = k->name();
1306 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1307 if (k != i) {
1308 // The dynamically resolved interface class is not the same as the one we used during dump time,
1309 // so we cannot use ik.
1310 return NULL;
1311 } else {
1312 assert(i->is_shared(), "must be");
1313 }
1314 }
1315
1316 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1317 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1318 if (new_ik != NULL) {
1319 // The class is changed by CFLH. Return the new class. The shared class is
1320 // not used.
1321 return new_ik;
1322 }
1323
1324 // Adjust methods to recover missing data. They need addresses for
1325 // interpreter entry points and their default native method address
1326 // must be reset.
1327
1328 // Updating methods must be done under a lock so multiple
1329 // threads don't update these in parallel
1330 //
1331 // Shared classes are all currently loaded by either the bootstrap or
1332 // internal parallel class loaders, so this will never cause a deadlock
1333 // on a custom class loader lock.
1334
1335 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1336 {
1337 HandleMark hm(THREAD);
1338 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1339 check_loader_lock_contention(lockObject, THREAD);
1340 ObjectLocker ol(lockObject, THREAD, true);
1341 // prohibited package check assumes all classes loaded from archive call
1342 // restore_unshareable_info which calls ik->set_package()
1343 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1344 }
1345
1346 ik->print_class_load_logging(loader_data, NULL, NULL);
1347
1348 // For boot loader, ensure that GetSystemPackage knows that a class in this
1349 // package was loaded.
1350 if (class_loader.is_null()) {
1351 int path_index = ik->shared_classpath_index();
1352 ResourceMark rm(THREAD);
1353 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1354 }
1355
1356 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1357 // Only dump the classes that can be stored into CDS archive
1358 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1359 ResourceMark rm(THREAD);
1360 classlist_file->print_cr("%s", ik->name()->as_C_string());
1361 classlist_file->flush();
1362 }
1363 }
1364
1365 // notify a class loaded from shared object
1366 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1367
1368 ik->set_has_passed_fingerprint_check(false);
1369 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1370 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1371 uint64_t cds_fp = ik->get_stored_fingerprint();
1372 if (aot_fp != 0 && aot_fp == cds_fp) {
1373 // This class matches with a class saved in an AOT library
1374 ik->set_has_passed_fingerprint_check(true);
1375 } else {
1376 if (log_is_enabled(Info, class, fingerprint)) {
1377 ResourceMark rm(THREAD);
1378 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1379 }
1380 }
1381 }
1382
1383 return ik;
1384 }
1385 #endif // INCLUDE_CDS
1386
1387 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1388
1389 if (class_loader.is_null()) {
1390 ResourceMark rm(THREAD);
1391 PackageEntry* pkg_entry = NULL;
1392 bool search_only_bootloader_append = false;
1393 ClassLoaderData *loader_data = class_loader_data(class_loader);
1394
1395 // Find the package in the boot loader's package entry table.
1396 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1397 if (pkg_name != NULL) {
1398 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1399 }
1400
1401 // Prior to attempting to load the class, enforce the boot loader's
1402 // visibility boundaries.
1403 if (!Universe::is_module_initialized()) {
1404 // During bootstrapping, prior to module initialization, any
1405 // class attempting to be loaded must be checked against the
1406 // java.base packages in the boot loader's PackageEntryTable.
1407 // No class outside of java.base is allowed to be loaded during
1408 // this bootstrapping window.
1409 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1410 // Class is either in the unnamed package or in
1411 // a named package within the unnamed module. Either
1412 // case is outside of java.base, do not attempt to
1413 // load the class post java.base definition. If
1414 // java.base has not been defined, let the class load
1415 // and its package will be checked later by
1416 // ModuleEntryTable::verify_javabase_packages.
1417 if (ModuleEntryTable::javabase_defined()) {
1418 return NULL;
1419 }
1420 } else {
1421 // Check that the class' package is defined within java.base.
1422 ModuleEntry* mod_entry = pkg_entry->module();
1423 Symbol* mod_entry_name = mod_entry->name();
1424 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1425 return NULL;
1426 }
1427 }
1428 } else {
1429 // After the module system has been initialized, check if the class'
1430 // package is in a module defined to the boot loader.
1431 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1432 // Class is either in the unnamed package, in a named package
1433 // within a module not defined to the boot loader or in a
1434 // a named package within the unnamed module. In all cases,
1435 // limit visibility to search for the class only in the boot
1436 // loader's append path.
1437 if (!ClassLoader::has_bootclasspath_append()) {
1438 // If there is no bootclasspath append entry, no need to continue
1439 // searching.
1440 return NULL;
1441 }
1442 search_only_bootloader_append = true;
1443 }
1444 }
1445
1446 // Prior to bootstrapping's module initialization, never load a class outside
1447 // of the boot loader's module path
1448 assert(Universe::is_module_initialized() ||
1449 !search_only_bootloader_append,
1450 "Attempt to load a class outside of boot loader's module path");
1451
1452 // Search for classes in the CDS archive.
1453 InstanceKlass* k = NULL;
1454 {
1455 #if INCLUDE_CDS
1456 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1457 k = load_shared_boot_class(class_name, THREAD);
1458 #endif
1459 }
1460
1461 if (k == NULL) {
1462 // Use VM class loader
1463 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1464 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1465 }
1466
1467 // find_or_define_instance_class may return a different InstanceKlass
1468 if (k != NULL) {
1469 InstanceKlass* defined_k =
1470 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1471 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1472 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1473 assert(defined_k != NULL, "Should have a klass if there's no exception");
1474 loader_data->add_to_deallocate_list(k);
1475 k = defined_k;
1476 } else if (HAS_PENDING_EXCEPTION) {
1477 loader_data->add_to_deallocate_list(k);
1478 return NULL;
1479 }
1480 }
1481 return k;
1482 } else {
1483 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1484 ResourceMark rm(THREAD);
1485
1486 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1487 JavaThread* jt = (JavaThread*) THREAD;
1488
1489 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1490 ClassLoader::perf_app_classload_selftime(),
1491 ClassLoader::perf_app_classload_count(),
1492 jt->get_thread_stat()->perf_recursion_counts_addr(),
1493 jt->get_thread_stat()->perf_timers_addr(),
1494 PerfClassTraceTime::CLASS_LOAD);
1495
1496 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1497 // Translate to external class name format, i.e., convert '/' chars to '.'
1498 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1499
1500 JavaValue result(T_OBJECT);
1501
1502 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1503
1504 // Call public unsynchronized loadClass(String) directly for all class loaders.
1505 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1506 // acquire a class-name based lock rather than the class loader object lock.
1507 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1508 JavaCalls::call_virtual(&result,
1509 class_loader,
1510 spec_klass,
1511 vmSymbols::loadClass_name(),
1512 vmSymbols::string_class_signature(),
1513 string,
1514 CHECK_NULL);
1515
1516 assert(result.get_type() == T_OBJECT, "just checking");
1517 oop obj = (oop) result.get_jobject();
1518
1519 // Primitive classes return null since forName() can not be
1520 // used to obtain any of the Class objects representing primitives or void
1521 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1522 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1523 // For user defined Java class loaders, check that the name returned is
1524 // the same as that requested. This check is done for the bootstrap
1525 // loader when parsing the class file.
1526 if (class_name == k->name()) {
1527 return k;
1528 }
1529 }
1530 // Class is not found or has the wrong name, return NULL
1531 return NULL;
1532 }
1533 }
1534
1535 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1536 EventClassDefine event;
1537 if (event.should_commit()) {
1538 event.set_definedClass(k);
1539 event.set_definingClassLoader(def_cld);
1540 event.commit();
1541 }
1542 }
1543
1544 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1545
1546 HandleMark hm(THREAD);
1547 ClassLoaderData* loader_data = k->class_loader_data();
1548 Handle class_loader_h(THREAD, loader_data->class_loader());
1549
1550 // for bootstrap and other parallel classloaders don't acquire lock,
1551 // use placeholder token
1552 // If a parallelCapable class loader calls define_instance_class instead of
1553 // find_or_define_instance_class to get here, we have a timing
1554 // hole with systemDictionary updates and check_constraints
1555 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1556 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1557 compute_loader_lock_object(class_loader_h, THREAD)),
1558 "define called without lock");
1559 }
1560
1561 // Check class-loading constraints. Throw exception if violation is detected.
1562 // Grabs and releases SystemDictionary_lock
1563 // The check_constraints/find_class call and update_dictionary sequence
1564 // must be "atomic" for a specific class/classloader pair so we never
1565 // define two different instanceKlasses for that class/classloader pair.
1566 // Existing classloaders will call define_instance_class with the
1567 // classloader lock held
1568 // Parallel classloaders will call find_or_define_instance_class
1569 // which will require a token to perform the define class
1570 Symbol* name_h = k->name();
1571 Dictionary* dictionary = loader_data->dictionary();
1572 unsigned int d_hash = dictionary->compute_hash(name_h);
1573 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1574
1575 // Register class just loaded with class loader (placed in ArrayList)
1576 // Note we do this before updating the dictionary, as this can
1577 // fail with an OutOfMemoryError (if it does, we will *not* put this
1578 // class in the dictionary and will not update the class hierarchy).
1579 // JVMTI FollowReferences needs to find the classes this way.
1580 if (k->class_loader() != NULL) {
1581 methodHandle m(THREAD, Universe::loader_addClass_method());
1582 JavaValue result(T_VOID);
1583 JavaCallArguments args(class_loader_h);
1584 args.push_oop(Handle(THREAD, k->java_mirror()));
1585 JavaCalls::call(&result, m, &args, CHECK);
1586 }
1587
1588 // Add the new class. We need recompile lock during update of CHA.
1589 {
1590 unsigned int p_hash = placeholders()->compute_hash(name_h);
1591 int p_index = placeholders()->hash_to_index(p_hash);
1592
1593 MutexLocker mu_r(THREAD, Compile_lock);
1594
1595 // Add to class hierarchy, initialize vtables, and do possible
1596 // deoptimizations.
1597 add_to_hierarchy(k, CHECK); // No exception, but can block
1598
1599 // Add to systemDictionary - so other classes can see it.
1600 // Grabs and releases SystemDictionary_lock
1601 update_dictionary(d_hash, p_index, p_hash,
1602 k, class_loader_h, THREAD);
1603 }
1604 k->eager_initialize(THREAD);
1605
1606 // notify jvmti
1607 if (JvmtiExport::should_post_class_load()) {
1608 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1609 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1610
1611 }
1612 post_class_define_event(k, loader_data);
1613 }
1614
1615 // Support parallel classloading
1616 // All parallel class loaders, including bootstrap classloader
1617 // lock a placeholder entry for this class/class_loader pair
1618 // to allow parallel defines of different classes for this class loader
1619 // With AllowParallelDefine flag==true, in case they do not synchronize around
1620 // FindLoadedClass/DefineClass, calls, we check for parallel
1621 // loading for them, wait if a defineClass is in progress
1622 // and return the initial requestor's results
1623 // This flag does not apply to the bootstrap classloader.
1624 // With AllowParallelDefine flag==false, call through to define_instance_class
1625 // which will throw LinkageError: duplicate class definition.
1626 // False is the requested default.
1627 // For better performance, the class loaders should synchronize
1628 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1629 // potentially waste time reading and parsing the bytestream.
1630 // Note: VM callers should ensure consistency of k/class_name,class_loader
1631 // Be careful when modifying this code: once you have run
1632 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1633 // you need to find_and_remove it before returning.
1634 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1635 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1636 InstanceKlass* k, TRAPS) {
1637
1638 Symbol* name_h = k->name(); // passed in class_name may be null
1639 ClassLoaderData* loader_data = class_loader_data(class_loader);
1640 Dictionary* dictionary = loader_data->dictionary();
1641
1642 unsigned int d_hash = dictionary->compute_hash(name_h);
1643
1644 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1645 unsigned int p_hash = placeholders()->compute_hash(name_h);
1646 int p_index = placeholders()->hash_to_index(p_hash);
1647 PlaceholderEntry* probe;
1648
1649 {
1650 MutexLocker mu(THREAD, SystemDictionary_lock);
1651 // First check if class already defined
1652 if (is_parallelDefine(class_loader)) {
1653 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1654 if (check != NULL) {
1655 return check;
1656 }
1657 }
1658
1659 // Acquire define token for this class/classloader
1660 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1661 // Wait if another thread defining in parallel
1662 // All threads wait - even those that will throw duplicate class: otherwise
1663 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1664 // if other thread has not finished updating dictionary
1665 while (probe->definer() != NULL) {
1666 SystemDictionary_lock->wait();
1667 }
1668 // Only special cases allow parallel defines and can use other thread's results
1669 // Other cases fall through, and may run into duplicate defines
1670 // caught by finding an entry in the SystemDictionary
1671 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1672 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1673 SystemDictionary_lock->notify_all();
1674 #ifdef ASSERT
1675 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1676 assert(check != NULL, "definer missed recording success");
1677 #endif
1678 return probe->instance_klass();
1679 } else {
1680 // This thread will define the class (even if earlier thread tried and had an error)
1681 probe->set_definer(THREAD);
1682 }
1683 }
1684
1685 define_instance_class(k, THREAD);
1686
1687 Handle linkage_exception = Handle(); // null handle
1688
1689 // definer must notify any waiting threads
1690 {
1691 MutexLocker mu(THREAD, SystemDictionary_lock);
1692 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1693 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1694 if (probe != NULL) {
1695 if (HAS_PENDING_EXCEPTION) {
1696 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1697 CLEAR_PENDING_EXCEPTION;
1698 } else {
1699 probe->set_instance_klass(k);
1700 }
1701 probe->set_definer(NULL);
1702 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1703 SystemDictionary_lock->notify_all();
1704 }
1705 }
1706
1707 // Can't throw exception while holding lock due to rank ordering
1708 if (linkage_exception() != NULL) {
1709 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1710 }
1711
1712 return k;
1713 }
1714
1715 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1716 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1717 if (class_loader.is_null()) {
1718 return Handle(THREAD, _system_loader_lock_obj);
1719 } else {
1720 return class_loader;
1721 }
1722 }
1723
1724 // This method is added to check how often we have to wait to grab loader
1725 // lock. The results are being recorded in the performance counters defined in
1726 // ClassLoader::_sync_systemLoaderLockContentionRate and
1727 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1728 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1729 if (!UsePerfData) {
1730 return;
1731 }
1732
1733 assert(!loader_lock.is_null(), "NULL lock object");
1734
1735 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1736 == ObjectSynchronizer::owner_other) {
1737 // contention will likely happen, so increment the corresponding
1738 // contention counter.
1739 if (loader_lock() == _system_loader_lock_obj) {
1740 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1741 } else {
1742 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1743 }
1744 }
1745 }
1746
1747 // ----------------------------------------------------------------------------
1748 // Lookup
1749
1750 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1751 Symbol* class_name,
1752 Dictionary* dictionary) {
1753 assert_locked_or_safepoint(SystemDictionary_lock);
1754 int index = dictionary->hash_to_index(hash);
1755 return dictionary->find_class(index, hash, class_name);
1756 }
1757
1758
1759 // Basic find on classes in the midst of being loaded
1760 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1761 ClassLoaderData* loader_data) {
1762 assert_locked_or_safepoint(SystemDictionary_lock);
1763 unsigned int p_hash = placeholders()->compute_hash(class_name);
1764 int p_index = placeholders()->hash_to_index(p_hash);
1765 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1766 }
1767
1768
1769 // Used for assertions and verification only
1770 // Precalculating the hash and index is an optimization because there are many lookups
1771 // before adding the class.
1772 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1773 assert_locked_or_safepoint(SystemDictionary_lock);
1774 #ifndef ASSERT
1775 guarantee(VerifyBeforeGC ||
1776 VerifyDuringGC ||
1777 VerifyBeforeExit ||
1778 VerifyDuringStartup ||
1779 VerifyAfterGC, "too expensive");
1780 #endif
1781
1782 Dictionary* dictionary = loader_data->dictionary();
1783 unsigned int d_hash = dictionary->compute_hash(class_name);
1784 return find_class(d_hash, class_name, dictionary);
1785 }
1786
1787
1788 // ----------------------------------------------------------------------------
1789 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1790 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1791 // before a new class is used.
1792
1793 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1794 assert(k != NULL, "just checking");
1795 assert_locked_or_safepoint(Compile_lock);
1796
1797 k->set_init_state(InstanceKlass::loaded);
1798 // make sure init_state store is already done.
1799 // The compiler reads the hierarchy outside of the Compile_lock.
1800 // Access ordering is used to add to hierarchy.
1801
1802 // Link into hierachy.
1803 k->append_to_sibling_list(); // add to superklass/sibling list
1804 k->process_interfaces(THREAD); // handle all "implements" declarations
1805
1806 // Now flush all code that depended on old class hierarchy.
1807 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1808 CodeCache::flush_dependents_on(k);
1809 }
1810
1811 // ----------------------------------------------------------------------------
1812 // GC support
1813
1814 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1815 // Note: anonymous classes are not in the SD.
1816 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1817
1818 bool unloading_occurred;
1819 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1820 {
1821 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1822 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1823 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1824 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1825 if (unloading_occurred) {
1826 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1827 JFR_ONLY(Jfr::on_unloading_classes();)
1828
1829 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1830 ClassLoaderDataGraph::clean_module_and_package_info();
1831 constraints()->purge_loader_constraints();
1832 resolution_errors()->purge_resolution_errors();
1833 }
1834 }
1835
1836 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1837
1838 if (unloading_occurred) {
1839 SymbolTable::trigger_cleanup();
1840
1841 // Oops referenced by the protection domain cache table may get unreachable independently
1842 // of the class loader (eg. cached protection domain oops). So we need to
1843 // explicitly unlink them here.
1844 // All protection domain oops are linked to the caller class, so if nothing
1845 // unloads, this is not needed.
1846 _pd_cache_table->trigger_cleanup();
1847 }
1848
1849 return unloading_occurred;
1850 }
1851
1852 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1853 f->do_oop(&_java_system_loader);
1854 f->do_oop(&_java_platform_loader);
1855 f->do_oop(&_system_loader_lock_obj);
1856 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1857
1858 // Visit extra methods
1859 invoke_method_table()->oops_do(f);
1860
1861 if (include_handles) {
1862 OopStorageSet::vm_global()->oops_do(f);
1863 }
1864 }
1865
1866 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1867 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1868 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1869 it->push(well_known_klass_addr((WKID)id));
1870 }
1871 }
1872
1873 void SystemDictionary::methods_do(void f(Method*)) {
1874 // Walk methods in loaded classes
1875 MutexLocker ml(ClassLoaderDataGraph_lock);
1876 ClassLoaderDataGraph::methods_do(f);
1877 // Walk method handle intrinsics
1878 invoke_method_table()->methods_do(f);
1879 }
1880
1881 // ----------------------------------------------------------------------------
1882 // Initialization
1883
1884 void SystemDictionary::initialize(TRAPS) {
1885 // Allocate arrays
1886 _placeholders = new PlaceholderTable(_placeholder_table_size);
1887 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1888 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1889 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1890 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1891
1892 // Allocate private object used as system class loader lock
1893 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1894 // Initialize basic classes
1895 resolve_well_known_classes(CHECK);
1896 }
1897
1898 // Compact table of directions on the initialization of klasses:
1899 static const short wk_init_info[] = {
1900 #define WK_KLASS_INIT_INFO(name, symbol) \
1901 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1902
1903 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1904 #undef WK_KLASS_INIT_INFO
1905 0
1906 };
1907
1908 #ifdef ASSERT
1909 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1910 int sid;
1911 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1912 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1913 if (class_name == symbol) {
1914 return true;
1915 }
1916 }
1917 return false;
1918 }
1919 #endif
1920
1921 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1922 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1923 int sid = wk_init_info[id - FIRST_WKID];
1924 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1925 InstanceKlass** klassp = &_well_known_klasses[id];
1926
1927 if ((*klassp) == NULL) {
1928 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1929 (*klassp) = InstanceKlass::cast(k);
1930 }
1931 return ((*klassp) != NULL);
1932 }
1933
1934 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1935 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1936 for (int id = (int)start_id; id < (int)limit_id; id++) {
1937 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1938 resolve_wk_klass((WKID)id, CHECK);
1939 }
1940
1941 // move the starting value forward to the limit:
1942 start_id = limit_id;
1943 }
1944
1945 void SystemDictionary::resolve_well_known_classes(TRAPS) {
1946 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
1947
1948 // Create the ModuleEntry for java.base. This call needs to be done here,
1949 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1950 ClassLoader::classLoader_init2(CHECK);
1951
1952 // Preload commonly used klasses
1953 WKID scan = FIRST_WKID;
1954 // first do Object, then String, Class
1955 #if INCLUDE_CDS
1956 if (UseSharedSpaces) {
1957 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1958
1959 // It's unsafe to access the archived heap regions before they
1960 // are fixed up, so we must do the fixup as early as possible
1961 // before the archived java objects are accessed by functions
1962 // such as java_lang_Class::restore_archived_mirror and
1963 // ConstantPool::restore_unshareable_info (restores the archived
1964 // resolved_references array object).
1965 //
1966 // HeapShared::fixup_mapped_heap_regions() fills the empty
1967 // spaces in the archived heap regions and may use
1968 // SystemDictionary::Object_klass(), so we can do this only after
1969 // Object_klass is resolved. See the above resolve_wk_klasses_through()
1970 // call. No mirror objects are accessed/restored in the above call.
1971 // Mirrors are restored after java.lang.Class is loaded.
1972 HeapShared::fixup_mapped_heap_regions();
1973
1974 // Initialize the constant pool for the Object_class
1975 assert(Object_klass()->is_shared(), "must be");
1976 Object_klass()->constants()->restore_unshareable_info(CHECK);
1977 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1978 } else
1979 #endif
1980 {
1981 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1982 }
1983
1984 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
1985
1986 java_lang_Object::register_natives(CHECK);
1987
1988 // Calculate offsets for String and Class classes since they are loaded and
1989 // can be used after this point.
1990 java_lang_String::compute_offsets();
1991 java_lang_Class::compute_offsets();
1992
1993 // Fixup mirrors for classes loaded before java.lang.Class.
1994 // These calls iterate over the objects currently in the perm gen
1995 // so calling them at this point is matters (not before when there
1996 // are fewer objects and not later after there are more objects
1997 // in the perm gen.
1998 Universe::initialize_basic_type_mirrors(CHECK);
1999 Universe::fixup_mirrors(CHECK);
2000
2001 // do a bunch more:
2002 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2003
2004 // Preload ref klasses and set reference types
2005 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2006 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2007
2008 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2009 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2010 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2011 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2012 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2013
2014 // JSR 292 classes
2015 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2016 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2017 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2018 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2019 WKID last = WKID_LIMIT;
2020 resolve_wk_klasses_until(last, scan, CHECK);
2021
2022 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2023 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2024 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2025 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2026 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2027 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2028 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2029 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2030 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2031 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2032
2033 #ifdef ASSERT
2034 if (UseSharedSpaces) {
2035 assert(JvmtiExport::is_early_phase(),
2036 "All well known classes must be resolved in JVMTI early phase");
2037 for (int i = FIRST_WKID; i < last; i++) {
2038 InstanceKlass* k = _well_known_klasses[i];
2039 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2040 }
2041 }
2042 #endif
2043 }
2044
2045 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2046 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2047 BasicType SystemDictionary::box_klass_type(Klass* k) {
2048 assert(k != NULL, "");
2049 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2050 if (_box_klasses[i] == k)
2051 return (BasicType)i;
2052 }
2053 return T_OBJECT;
2054 }
2055
2056 // Constraints on class loaders. The details of the algorithm can be
2057 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2058 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2059 // that the dictionary needs to maintain a set of contraints that
2060 // must be satisfied by all classes in the dictionary.
2061 // if defining is true, then LinkageError if already in dictionary
2062 // if initiating loader, then ok if InstanceKlass matches existing entry
2063
2064 void SystemDictionary::check_constraints(unsigned int d_hash,
2065 InstanceKlass* k,
2066 Handle class_loader,
2067 bool defining,
2068 TRAPS) {
2069 ResourceMark rm(THREAD);
2070 stringStream ss;
2071 bool throwException = false;
2072
2073 {
2074 Symbol *name = k->name();
2075 ClassLoaderData *loader_data = class_loader_data(class_loader);
2076
2077 MutexLocker mu(THREAD, SystemDictionary_lock);
2078
2079 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2080 if (check != NULL) {
2081 // If different InstanceKlass - duplicate class definition,
2082 // else - ok, class loaded by a different thread in parallel.
2083 // We should only have found it if it was done loading and ok to use.
2084 // The dictionary only holds instance classes, placeholders
2085 // also hold array classes.
2086
2087 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2088 if ((defining == true) || (k != check)) {
2089 throwException = true;
2090 ss.print("loader %s", loader_data->loader_name_and_id());
2091 ss.print(" attempted duplicate %s definition for %s. (%s)",
2092 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2093 } else {
2094 return;
2095 }
2096 }
2097
2098 #ifdef ASSERT
2099 Symbol* ph_check = find_placeholder(name, loader_data);
2100 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2101 #endif
2102
2103 if (throwException == false) {
2104 if (constraints()->check_or_update(k, class_loader, name) == false) {
2105 throwException = true;
2106 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2107 ss.print(" wants to load %s %s.",
2108 k->external_kind(), k->external_name());
2109 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2110 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2111 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2112 existing_klass->external_kind(),
2113 existing_klass->class_loader_data()->loader_name_and_id(),
2114 existing_klass->class_in_module_of_loader(false, true));
2115 } else {
2116 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2117 }
2118 }
2119 }
2120 }
2121
2122 // Throw error now if needed (cannot throw while holding
2123 // SystemDictionary_lock because of rank ordering)
2124 if (throwException == true) {
2125 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2126 }
2127 }
2128
2129 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2130 // have been called.
2131 void SystemDictionary::update_dictionary(unsigned int d_hash,
2132 int p_index, unsigned int p_hash,
2133 InstanceKlass* k,
2134 Handle class_loader,
2135 TRAPS) {
2136 // Compile_lock prevents systemDictionary updates during compilations
2137 assert_locked_or_safepoint(Compile_lock);
2138 Symbol* name = k->name();
2139 ClassLoaderData *loader_data = class_loader_data(class_loader);
2140
2141 {
2142 MutexLocker mu1(THREAD, SystemDictionary_lock);
2143
2144 // Make a new dictionary entry.
2145 Dictionary* dictionary = loader_data->dictionary();
2146 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2147 if (sd_check == NULL) {
2148 dictionary->add_klass(d_hash, name, k);
2149 }
2150 #ifdef ASSERT
2151 sd_check = find_class(d_hash, name, dictionary);
2152 assert (sd_check != NULL, "should have entry in dictionary");
2153 // Note: there may be a placeholder entry: for circularity testing
2154 // or for parallel defines
2155 #endif
2156 SystemDictionary_lock->notify_all();
2157 }
2158 }
2159
2160
2161 // Try to find a class name using the loader constraints. The
2162 // loader constraints might know about a class that isn't fully loaded
2163 // yet and these will be ignored.
2164 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2165 Symbol* class_name, Handle class_loader, TRAPS) {
2166
2167 // First see if it has been loaded directly.
2168 // Force the protection domain to be null. (This removes protection checks.)
2169 Handle no_protection_domain;
2170 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2171 no_protection_domain, CHECK_NULL);
2172 if (klass != NULL)
2173 return klass;
2174
2175 // Now look to see if it has been loaded elsewhere, and is subject to
2176 // a loader constraint that would require this loader to return the
2177 // klass that is already loaded.
2178 if (Signature::is_array(class_name)) {
2179 // For array classes, their Klass*s are not kept in the
2180 // constraint table. The element Klass*s are.
2181 SignatureStream ss(class_name, false);
2182 int ndims = ss.skip_array_prefix(); // skip all '['s
2183 BasicType t = ss.type();
2184 if (t != T_OBJECT) {
2185 klass = Universe::typeArrayKlassObj(t);
2186 } else {
2187 MutexLocker mu(THREAD, SystemDictionary_lock);
2188 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2189 }
2190 // If element class already loaded, allocate array klass
2191 if (klass != NULL) {
2192 klass = klass->array_klass_or_null(ndims);
2193 }
2194 } else {
2195 MutexLocker mu(THREAD, SystemDictionary_lock);
2196 // Non-array classes are easy: simply check the constraint table.
2197 klass = constraints()->find_constrained_klass(class_name, class_loader);
2198 }
2199
2200 return klass;
2201 }
2202
2203
2204 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2205 Handle class_loader1,
2206 Handle class_loader2,
2207 Thread* THREAD) {
2208 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2209 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2210
2211 Symbol* constraint_name = NULL;
2212
2213 if (!Signature::is_array(class_name)) {
2214 constraint_name = class_name;
2215 } else {
2216 // For array classes, their Klass*s are not kept in the
2217 // constraint table. The element classes are.
2218 SignatureStream ss(class_name, false);
2219 ss.skip_array_prefix(); // skip all '['s
2220 if (!ss.has_envelope()) {
2221 return true; // primitive types always pass
2222 }
2223 constraint_name = ss.as_symbol();
2224 // Increment refcount to keep constraint_name alive after
2225 // SignatureStream is destructed. It will be decremented below
2226 // before returning.
2227 constraint_name->increment_refcount();
2228 }
2229
2230 Dictionary* dictionary1 = loader_data1->dictionary();
2231 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2232
2233 Dictionary* dictionary2 = loader_data2->dictionary();
2234 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2235
2236 {
2237 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2238 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2239 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2240 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2241 klass2, class_loader2);
2242 if (Signature::is_array(class_name)) {
2243 constraint_name->decrement_refcount();
2244 }
2245 return result;
2246 }
2247 }
2248
2249 // Add entry to resolution error table to record the error when the first
2250 // attempt to resolve a reference to a class has failed.
2251 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2252 Symbol* error, Symbol* message) {
2253 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2254 int index = resolution_errors()->hash_to_index(hash);
2255 {
2256 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2257 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2258 }
2259 }
2260
2261 // Delete a resolution error for RedefineClasses for a constant pool is going away
2262 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2263 resolution_errors()->delete_entry(pool);
2264 }
2265
2266 // Lookup resolution error table. Returns error if found, otherwise NULL.
2267 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2268 Symbol** message) {
2269 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2270 int index = resolution_errors()->hash_to_index(hash);
2271 {
2272 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2273 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2274 if (entry != NULL) {
2275 *message = entry->message();
2276 return entry->error();
2277 } else {
2278 return NULL;
2279 }
2280 }
2281 }
2282
2283
2284 // Signature constraints ensure that callers and callees agree about
2285 // the meaning of type names in their signatures. This routine is the
2286 // intake for constraints. It collects them from several places:
2287 //
2288 // * LinkResolver::resolve_method (if check_access is true) requires
2289 // that the resolving class (the caller) and the defining class of
2290 // the resolved method (the callee) agree on each type in the
2291 // method's signature.
2292 //
2293 // * LinkResolver::resolve_interface_method performs exactly the same
2294 // checks.
2295 //
2296 // * LinkResolver::resolve_field requires that the constant pool
2297 // attempting to link to a field agree with the field's defining
2298 // class about the type of the field signature.
2299 //
2300 // * klassVtable::initialize_vtable requires that, when a class
2301 // overrides a vtable entry allocated by a superclass, that the
2302 // overriding method (i.e., the callee) agree with the superclass
2303 // on each type in the method's signature.
2304 //
2305 // * klassItable::initialize_itable requires that, when a class fills
2306 // in its itables, for each non-abstract method installed in an
2307 // itable, the method (i.e., the callee) agree with the interface
2308 // on each type in the method's signature.
2309 //
2310 // All those methods have a boolean (check_access, checkconstraints)
2311 // which turns off the checks. This is used from specialized contexts
2312 // such as bootstrapping, dumping, and debugging.
2313 //
2314 // No direct constraint is placed between the class and its
2315 // supertypes. Constraints are only placed along linked relations
2316 // between callers and callees. When a method overrides or implements
2317 // an abstract method in a supertype (superclass or interface), the
2318 // constraints are placed as if the supertype were the caller to the
2319 // overriding method. (This works well, since callers to the
2320 // supertype have already established agreement between themselves and
2321 // the supertype.) As a result of all this, a class can disagree with
2322 // its supertype about the meaning of a type name, as long as that
2323 // class neither calls a relevant method of the supertype, nor is
2324 // called (perhaps via an override) from the supertype.
2325 //
2326 //
2327 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2328 //
2329 // Make sure all class components (including arrays) in the given
2330 // signature will be resolved to the same class in both loaders.
2331 // Returns the name of the type that failed a loader constraint check, or
2332 // NULL if no constraint failed. No exception except OOME is thrown.
2333 // Arrays are not added to the loader constraint table, their elements are.
2334 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2335 Handle loader1, Handle loader2,
2336 bool is_method, TRAPS) {
2337 // Nothing to do if loaders are the same.
2338 if (loader1() == loader2()) {
2339 return NULL;
2340 }
2341
2342 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2343 if (ss.is_reference()) {
2344 Symbol* sig = ss.as_symbol();
2345 // Note: In the future, if template-like types can take
2346 // arguments, we will want to recognize them and dig out class
2347 // names hiding inside the argument lists.
2348 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2349 return sig;
2350 }
2351 }
2352 }
2353 return NULL;
2354 }
2355
2356
2357 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2358 Symbol* signature,
2359 TRAPS) {
2360 methodHandle empty;
2361 assert(MethodHandles::is_signature_polymorphic(iid) &&
2362 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2363 iid != vmIntrinsics::_invokeGeneric,
2364 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2365
2366 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2367 int index = invoke_method_table()->hash_to_index(hash);
2368 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2369 methodHandle m;
2370 if (spe == NULL || spe->method() == NULL) {
2371 spe = NULL;
2372 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2373 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2374 if (!Arguments::is_interpreter_only()) {
2375 // Generate a compiled form of the MH intrinsic.
2376 AdapterHandlerLibrary::create_native_wrapper(m);
2377 // Check if have the compiled code.
2378 if (!m->has_compiled_code()) {
2379 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2380 "Out of space in CodeCache for method handle intrinsic");
2381 }
2382 }
2383 // Now grab the lock. We might have to throw away the new method,
2384 // if a racing thread has managed to install one at the same time.
2385 {
2386 MutexLocker ml(THREAD, SystemDictionary_lock);
2387 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2388 if (spe == NULL)
2389 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2390 if (spe->method() == NULL)
2391 spe->set_method(m());
2392 }
2393 }
2394
2395 assert(spe != NULL && spe->method() != NULL, "");
2396 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2397 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2398 "MH intrinsic invariant");
2399 return spe->method();
2400 }
2401
2402 // Helper for unpacking the return value from linkMethod and linkCallSite.
2403 static Method* unpack_method_and_appendix(Handle mname,
2404 Klass* accessing_klass,
2405 objArrayHandle appendix_box,
2406 Handle* appendix_result,
2407 TRAPS) {
2408 if (mname.not_null()) {
2409 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2410 if (m != NULL) {
2411 oop appendix = appendix_box->obj_at(0);
2412 if (TraceMethodHandles) {
2413 #ifndef PRODUCT
2414 ttyLocker ttyl;
2415 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2416 m->print();
2417 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2418 tty->cr();
2419 #endif //PRODUCT
2420 }
2421 (*appendix_result) = Handle(THREAD, appendix);
2422 // the target is stored in the cpCache and if a reference to this
2423 // MemberName is dropped we need a way to make sure the
2424 // class_loader containing this method is kept alive.
2425 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2426 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2427 this_key->record_dependency(m->method_holder());
2428 return mh();
2429 }
2430 }
2431 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2432 }
2433
2434 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2435 Symbol* name,
2436 Symbol* signature,
2437 Klass* accessing_klass,
2438 Handle *appendix_result,
2439 TRAPS) {
2440 assert(THREAD->can_call_java() ,"");
2441 Handle method_type =
2442 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2443
2444 int ref_kind = JVM_REF_invokeVirtual;
2445 oop name_oop = StringTable::intern(name, CHECK_NULL);
2446 Handle name_str (THREAD, name_oop);
2447 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2448 assert(appendix_box->obj_at(0) == NULL, "");
2449
2450 // This should not happen. JDK code should take care of that.
2451 if (accessing_klass == NULL || method_type.is_null()) {
2452 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2453 }
2454
2455 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2456 JavaCallArguments args;
2457 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2458 args.push_int(ref_kind);
2459 args.push_oop(Handle(THREAD, klass->java_mirror()));
2460 args.push_oop(name_str);
2461 args.push_oop(method_type);
2462 args.push_oop(appendix_box);
2463 JavaValue result(T_OBJECT);
2464 JavaCalls::call_static(&result,
2465 SystemDictionary::MethodHandleNatives_klass(),
2466 vmSymbols::linkMethod_name(),
2467 vmSymbols::linkMethod_signature(),
2468 &args, CHECK_NULL);
2469 Handle mname(THREAD, (oop) result.get_jobject());
2470 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2471 }
2472
2473 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2474 // We must ensure that all class loaders everywhere will reach this class, for any client.
2475 // This is a safe bet for public classes in java.lang, such as Object and String.
2476 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2477 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2478 static bool is_always_visible_class(oop mirror) {
2479 Klass* klass = java_lang_Class::as_Klass(mirror);
2480 if (klass->is_objArray_klass()) {
2481 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2482 }
2483 if (klass->is_typeArray_klass()) {
2484 return true; // primitive array
2485 }
2486 assert(klass->is_instance_klass(), "%s", klass->external_name());
2487 return klass->is_public() &&
2488 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2489 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2490 }
2491
2492 // Find or construct the Java mirror (java.lang.Class instance) for a
2493 // for the given field type signature, as interpreted relative to the
2494 // given class loader. Handles primitives, void, references, arrays,
2495 // and all other reflectable types, except method types.
2496 // N.B. Code in reflection should use this entry point.
2497 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2498 Klass* accessing_klass,
2499 Handle class_loader,
2500 Handle protection_domain,
2501 SignatureStream::FailureMode failure_mode,
2502 TRAPS) {
2503 Handle empty;
2504
2505 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2506 "one or the other, or perhaps neither");
2507
2508 SignatureStream ss(signature, false);
2509
2510 // What we have here must be a valid field descriptor,
2511 // and all valid field descriptors are supported.
2512 // Produce the same java.lang.Class that reflection reports.
2513 if (ss.is_primitive() || (ss.type() == T_VOID)) {
2514
2515 // It's a primitive. (Void has a primitive mirror too.)
2516 return Handle(THREAD, java_lang_Class::primitive_mirror(ss.type()));
2517
2518 } else if (ss.is_reference()) {
2519
2520 // It's a reference type.
2521 if (accessing_klass != NULL) {
2522 class_loader = Handle(THREAD, accessing_klass->class_loader());
2523 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2524 }
2525 Klass* constant_type_klass;
2526 if (failure_mode == SignatureStream::ReturnNull) {
2527 constant_type_klass = resolve_or_null(signature, class_loader, protection_domain,
2528 CHECK_(empty));
2529 } else {
2530 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2531 constant_type_klass = resolve_or_fail(signature, class_loader, protection_domain,
2532 throw_error, CHECK_(empty));
2533 }
2534 if (constant_type_klass == NULL) {
2535 return Handle(); // report failure this way
2536 }
2537 Handle mirror(THREAD, constant_type_klass->java_mirror());
2538
2539 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2540 if (accessing_klass != NULL) {
2541 Klass* sel_klass = constant_type_klass;
2542 bool fold_type_to_class = true;
2543 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2544 fold_type_to_class, CHECK_(empty));
2545 }
2546
2547 return mirror;
2548
2549 }
2550
2551 // Fall through to an error.
2552 assert(false, "unsupported mirror syntax");
2553 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2554 }
2555
2556
2557 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2558 // signature, as interpreted relative to the given class loader.
2559 // Because of class loader constraints, all method handle usage must be
2560 // consistent with this loader.
2561 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2562 Klass* accessing_klass,
2563 TRAPS) {
2564 Handle empty;
2565 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2566 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2567 int index = invoke_method_table()->hash_to_index(hash);
2568 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2569 if (spe != NULL && spe->method_type() != NULL) {
2570 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2571 return Handle(THREAD, spe->method_type());
2572 } else if (!THREAD->can_call_java()) {
2573 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2574 return Handle(); // do not attempt from within compiler, unless it was cached
2575 }
2576
2577 Handle class_loader, protection_domain;
2578 if (accessing_klass != NULL) {
2579 class_loader = Handle(THREAD, accessing_klass->class_loader());
2580 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2581 }
2582 bool can_be_cached = true;
2583 int npts = ArgumentCount(signature).size();
2584 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2585 int arg = 0;
2586 Handle rt; // the return type from the signature
2587 ResourceMark rm(THREAD);
2588 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2589 oop mirror = NULL;
2590 if (can_be_cached) {
2591 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2592 mirror = ss.as_java_mirror(Handle(), Handle(),
2593 SignatureStream::ReturnNull, CHECK_(empty));
2594 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2595 // Fall back to accessing_klass context.
2596 can_be_cached = false;
2597 }
2598 }
2599 if (!can_be_cached) {
2600 // Resolve, throwing a real error if it doesn't work.
2601 mirror = ss.as_java_mirror(class_loader, protection_domain,
2602 SignatureStream::NCDFError, CHECK_(empty));
2603 }
2604 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2605 if (ss.at_return_type())
2606 rt = Handle(THREAD, mirror);
2607 else
2608 pts->obj_at_put(arg++, mirror);
2609
2610 // Check accessibility.
2611 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2612 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2613 mirror = NULL; // safety
2614 // Emulate ConstantPool::verify_constant_pool_resolve.
2615 bool fold_type_to_class = true;
2616 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2617 fold_type_to_class, CHECK_(empty));
2618 }
2619 }
2620 assert(arg == npts, "");
2621
2622 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2623 JavaCallArguments args(Handle(THREAD, rt()));
2624 args.push_oop(pts);
2625 JavaValue result(T_OBJECT);
2626 JavaCalls::call_static(&result,
2627 SystemDictionary::MethodHandleNatives_klass(),
2628 vmSymbols::findMethodHandleType_name(),
2629 vmSymbols::findMethodHandleType_signature(),
2630 &args, CHECK_(empty));
2631 Handle method_type(THREAD, (oop) result.get_jobject());
2632
2633 if (can_be_cached) {
2634 // We can cache this MethodType inside the JVM.
2635 MutexLocker ml(THREAD, SystemDictionary_lock);
2636 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2637 if (spe == NULL)
2638 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2639 if (spe->method_type() == NULL) {
2640 spe->set_method_type(method_type());
2641 }
2642 }
2643
2644 // report back to the caller with the MethodType
2645 return method_type;
2646 }
2647
2648 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2649 Klass* accessing_klass,
2650 TRAPS) {
2651 Handle empty;
2652 ResourceMark rm(THREAD);
2653 SignatureStream ss(signature, /*is_method=*/ false);
2654 if (!ss.is_done()) {
2655 Handle class_loader, protection_domain;
2656 if (accessing_klass != NULL) {
2657 class_loader = Handle(THREAD, accessing_klass->class_loader());
2658 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2659 }
2660 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2661 ss.next();
2662 if (ss.is_done()) {
2663 return Handle(THREAD, mirror);
2664 }
2665 }
2666 return empty;
2667 }
2668
2669 // Ask Java code to find or construct a method handle constant.
2670 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2671 int ref_kind, //e.g., JVM_REF_invokeVirtual
2672 Klass* callee,
2673 Symbol* name,
2674 Symbol* signature,
2675 TRAPS) {
2676 Handle empty;
2677 if (caller == NULL) {
2678 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2679 }
2680 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2681 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2682
2683 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2684 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2685 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2686 java_lang_invoke_MemberName::set_name (mname(), name_str());
2687 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2688 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2689
2690 if (ref_kind == JVM_REF_invokeVirtual &&
2691 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2692 // Skip resolution for public signature polymorphic methods such as
2693 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2694 // They require appendix argument which MemberName resolution doesn't handle.
2695 // There's special logic on JDK side to handle them
2696 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2697 } else {
2698 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2699 }
2700
2701 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2702 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2703
2704 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2705 JavaCallArguments args;
2706 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2707 args.push_int(ref_kind);
2708 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2709 args.push_oop(name_str);
2710 args.push_oop(type);
2711 JavaValue result(T_OBJECT);
2712 JavaCalls::call_static(&result,
2713 SystemDictionary::MethodHandleNatives_klass(),
2714 vmSymbols::linkMethodHandleConstant_name(),
2715 vmSymbols::linkMethodHandleConstant_signature(),
2716 &args, CHECK_(empty));
2717 return Handle(THREAD, (oop) result.get_jobject());
2718 }
2719
2720 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2721 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2722 // with linkage results being stored back into the bootstrap specifier.
2723 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2724 // Resolve the bootstrap specifier, its name, type, and static arguments
2725 bootstrap_specifier.resolve_bsm(CHECK);
2726
2727 // This should not happen. JDK code should take care of that.
2728 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2729 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2730 }
2731
2732 bool is_indy = bootstrap_specifier.is_method_call();
2733 objArrayHandle appendix_box;
2734 if (is_indy) {
2735 // Some method calls may require an appendix argument. Arrange to receive it.
2736 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2737 assert(appendix_box->obj_at(0) == NULL, "");
2738 }
2739
2740 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2741 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2742 JavaCallArguments args;
2743 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2744 args.push_int(bootstrap_specifier.bss_index());
2745 args.push_oop(bootstrap_specifier.bsm());
2746 args.push_oop(bootstrap_specifier.name_arg());
2747 args.push_oop(bootstrap_specifier.type_arg());
2748 args.push_oop(bootstrap_specifier.arg_values());
2749 if (is_indy) {
2750 args.push_oop(appendix_box);
2751 }
2752 JavaValue result(T_OBJECT);
2753 JavaCalls::call_static(&result,
2754 SystemDictionary::MethodHandleNatives_klass(),
2755 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2756 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2757 &args, CHECK);
2758
2759 Handle value(THREAD, (oop) result.get_jobject());
2760 if (is_indy) {
2761 Handle appendix;
2762 Method* method = unpack_method_and_appendix(value,
2763 bootstrap_specifier.caller(),
2764 appendix_box,
2765 &appendix, CHECK);
2766 methodHandle mh(THREAD, method);
2767 bootstrap_specifier.set_resolved_method(mh, appendix);
2768 } else {
2769 bootstrap_specifier.set_resolved_value(value);
2770 }
2771
2772 // sanity check
2773 assert(bootstrap_specifier.is_resolved() ||
2774 (bootstrap_specifier.is_method_call() &&
2775 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2776 }
2777
2778 // Protection domain cache table handling
2779
2780 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2781 return _pd_cache_table->get(protection_domain);
2782 }
2783
2784 // ----------------------------------------------------------------------------
2785
2786 void SystemDictionary::print_on(outputStream *st) {
2787 CDS_ONLY(SystemDictionaryShared::print_on(st));
2788 GCMutexLocker mu(SystemDictionary_lock);
2789
2790 ClassLoaderDataGraph::print_dictionary(st);
2791
2792 // Placeholders
2793 placeholders()->print_on(st);
2794 st->cr();
2795
2796 // loader constraints - print under SD_lock
2797 constraints()->print_on(st);
2798 st->cr();
2799
2800 _pd_cache_table->print_on(st);
2801 st->cr();
2802 }
2803
2804 void SystemDictionary::print() { print_on(tty); }
2805
2806 void SystemDictionary::verify() {
2807 guarantee(constraints() != NULL,
2808 "Verify of loader constraints failed");
2809 guarantee(placeholders()->number_of_entries() >= 0,
2810 "Verify of placeholders failed");
2811
2812 GCMutexLocker mu(SystemDictionary_lock);
2813
2814 // Verify dictionary
2815 ClassLoaderDataGraph::verify_dictionary();
2816
2817 placeholders()->verify();
2818
2819 // Verify constraint table
2820 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2821 constraints()->verify(placeholders());
2822
2823 _pd_cache_table->verify();
2824 }
2825
2826 void SystemDictionary::dump(outputStream *st, bool verbose) {
2827 assert_locked_or_safepoint(SystemDictionary_lock);
2828 if (verbose) {
2829 print_on(st);
2830 } else {
2831 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2832 ClassLoaderDataGraph::print_table_statistics(st);
2833 placeholders()->print_table_statistics(st, "Placeholder Table");
2834 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2835 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2836 }
2837 }
2838
2839 TableStatistics SystemDictionary::placeholders_statistics() {
2840 MutexLocker ml(SystemDictionary_lock);
2841 return placeholders()->statistics_calculate();
2842 }
2843
2844 TableStatistics SystemDictionary::loader_constraints_statistics() {
2845 MutexLocker ml(SystemDictionary_lock);
2846 return constraints()->statistics_calculate();
2847 }
2848
2849 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2850 MutexLocker ml(SystemDictionary_lock);
2851 return pd_cache_table()->statistics_calculate();
2852 }
2853
2854 // Utility for dumping dictionaries.
2855 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2856 DCmdWithParser(output, heap),
2857 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2858 "BOOLEAN", false, "false") {
2859 _dcmdparser.add_dcmd_option(&_verbose);
2860 }
2861
2862 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2863 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2864 _verbose.value());
2865 VMThread::execute(&dumper);
2866 }
2867
2868 int SystemDictionaryDCmd::num_arguments() {
2869 ResourceMark rm;
2870 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2871 if (dcmd != NULL) {
2872 DCmdMark mark(dcmd);
2873 return dcmd->_dcmdparser.num_arguments();
2874 } else {
2875 return 0;
2876 }
2877 }