1 /*
2 * Copyright (c) 1997, 2019, 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/fieldType.hpp"
78 #include "runtime/handles.inline.hpp"
79 #include "runtime/java.hpp"
80 #include "runtime/javaCalls.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/orderAccess.hpp"
83 #include "runtime/sharedRuntime.hpp"
84 #include "runtime/signature.hpp"
85 #include "services/classLoadingService.hpp"
86 #include "services/diagnosticCommand.hpp"
87 #include "services/threadService.hpp"
88 #include "utilities/macros.hpp"
89 #if INCLUDE_CDS
90 #include "classfile/systemDictionaryShared.hpp"
91 #endif
92 #if INCLUDE_JFR
93 #include "jfr/jfr.hpp"
94 #endif
95
96 PlaceholderTable* SystemDictionary::_placeholders = NULL;
97 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
98 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
99 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
100 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
101
102 oop SystemDictionary::_system_loader_lock_obj = NULL;
103
104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
105 = { NULL /*, NULL...*/ };
106
107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
108
109 oop SystemDictionary::_java_system_loader = NULL;
110 oop SystemDictionary::_java_platform_loader = NULL;
111
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118 // ----------------------------------------------------------------------------
119 // Java-level SystemLoader and PlatformLoader
120
121 oop SystemDictionary::java_system_loader() {
122 return _java_system_loader;
123 }
124
125 oop SystemDictionary::java_platform_loader() {
126 return _java_platform_loader;
127 }
128
129 void SystemDictionary::compute_java_loaders(TRAPS) {
130 JavaValue result(T_OBJECT);
131 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
132 JavaCalls::call_static(&result,
133 class_loader_klass,
134 vmSymbols::getSystemClassLoader_name(),
135 vmSymbols::void_classloader_signature(),
136 CHECK);
137
138 _java_system_loader = (oop)result.get_jobject();
139
140 JavaCalls::call_static(&result,
141 class_loader_klass,
142 vmSymbols::getPlatformClassLoader_name(),
143 vmSymbols::void_classloader_signature(),
144 CHECK);
145
146 _java_platform_loader = (oop)result.get_jobject();
147 }
148
149 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
150 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
151 return ClassLoaderDataGraph::find_or_create(class_loader);
152 }
153
154 // ----------------------------------------------------------------------------
155 // Parallel class loading check
156
157 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
158 if (class_loader.is_null()) return true;
159 if (AlwaysLockClassLoader) return false;
160 return java_lang_ClassLoader::parallelCapable(class_loader());
161 }
162 // ----------------------------------------------------------------------------
163 // ParallelDefineClass flag does not apply to bootclass loader
164 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
165 if (class_loader.is_null()) return false;
166 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
167 return true;
168 }
169 return false;
170 }
171
172 // Returns true if the passed class loader is the builtin application class loader
173 // or a custom system class loader. A customer system class loader can be
174 // specified via -Djava.system.class.loader.
175 bool SystemDictionary::is_system_class_loader(oop class_loader) {
176 if (class_loader == NULL) {
177 return false;
178 }
179 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
180 class_loader == _java_system_loader);
181 }
182
183 // Returns true if the passed class loader is the platform class loader.
184 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
185 if (class_loader == NULL) {
186 return false;
187 }
188 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
189 }
190
191 // ----------------------------------------------------------------------------
192 // Resolving of classes
193
194 // Forwards to resolve_or_null
195
196 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
197 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
198 if (HAS_PENDING_EXCEPTION || klass == NULL) {
199 // can return a null klass
200 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
201 }
202 return klass;
203 }
204
205 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
206 bool throw_error,
207 Klass* klass, TRAPS) {
208 if (HAS_PENDING_EXCEPTION) {
209 // If we have a pending exception we forward it to the caller, unless throw_error is true,
210 // in which case we have to check whether the pending exception is a ClassNotFoundException,
211 // and if so convert it to a NoClassDefFoundError
212 // And chain the original ClassNotFoundException
213 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
214 ResourceMark rm(THREAD);
215 assert(klass == NULL, "Should not have result with exception pending");
216 Handle e(THREAD, PENDING_EXCEPTION);
217 CLEAR_PENDING_EXCEPTION;
218 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
219 } else {
220 return NULL;
221 }
222 }
223 // Class not found, throw appropriate error or exception depending on value of throw_error
224 if (klass == NULL) {
225 ResourceMark rm(THREAD);
226 if (throw_error) {
227 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
228 } else {
229 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
230 }
231 }
232 return klass;
233 }
234
235
236 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
237 bool throw_error, TRAPS)
238 {
239 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
240 }
241
242
243 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
244
245 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
246 if (FieldType::is_array(class_name)) {
247 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
248 } else {
249 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
250 }
251 }
252
253 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
254 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
255 Handle class_loader,
256 Handle protection_domain,
257 TRAPS) {
258 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
259 if (FieldType::is_obj(class_name)) {
260 ResourceMark rm(THREAD);
261 // Ignore wrapping L and ;.
262 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
263 class_name->utf8_length() - 2);
264 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
265 } else {
266 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
267 }
268 }
269
270 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
271 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
272 }
273
274 // Forwards to resolve_instance_class_or_null
275
276 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
277 Handle class_loader,
278 Handle protection_domain,
279 TRAPS) {
280 assert(FieldType::is_array(class_name), "must be array");
281 Klass* k = NULL;
282 FieldArrayInfo fd;
283 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
284 // of this call
285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
286 if (t == T_OBJECT) {
287 // naked oop "k" is OK here -- we assign back into it
288 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
289 class_loader,
290 protection_domain,
291 CHECK_NULL);
292 if (k != NULL) {
293 k = k->array_klass(fd.dimension(), CHECK_NULL);
294 }
295 } else {
296 k = Universe::typeArrayKlassObj(t);
297 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
298 }
299 return k;
300 }
301
302
303 // Must be called for any super-class or super-interface resolution
304 // during class definition to allow class circularity checking
305 // super-interface callers:
306 // parse_interfaces - for defineClass & jvmtiRedefineClasses
307 // super-class callers:
308 // ClassFileParser - for defineClass & jvmtiRedefineClasses
309 // load_shared_class - while loading a class from shared archive
310 // resolve_instance_class_or_null:
311 // via: handle_parallel_super_load
312 // when resolving a class that has an existing placeholder with
313 // a saved superclass [i.e. a defineClass is currently in progress]
314 // if another thread is trying to resolve the class, it must do
315 // super-class checks on its own thread to catch class circularity
316 // This last call is critical in class circularity checking for cases
317 // where classloading is delegated to different threads and the
318 // classloader lock is released.
319 // Take the case: Base->Super->Base
320 // 1. If thread T1 tries to do a defineClass of class Base
321 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
322 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
323 // so it tries to load Super
324 // 3. If we load the class internally, or user classloader uses same thread
325 // loadClassFromxxx or defineClass via parseClassFile Super ...
326 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
327 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
328 // 3.4 calls resolve_super_or_fail Base
329 // 3.5 finds T1,Base -> throws class circularity
330 //OR 4. If T2 tries to resolve Super via defineClass Super ...
331 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
332 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
333 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
334 // 4.4 finds T2, Super -> throws class circularity
335 // Must be called, even if superclass is null, since this is
336 // where the placeholder entry is created which claims this
337 // thread is loading this class/classloader.
338 // Be careful when modifying this code: once you have run
339 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
340 // you need to find_and_remove it before returning.
341 // So be careful to not exit with a CHECK_ macro betweeen these calls.
342 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
343 Symbol* super_name,
344 Handle class_loader,
345 Handle protection_domain,
346 bool is_superclass,
347 TRAPS) {
348 assert(!FieldType::is_array(super_name), "invalid super class name");
349 #if INCLUDE_CDS
350 if (DumpSharedSpaces) {
351 // Special processing for handling UNREGISTERED shared classes.
352 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
353 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
354 if (k) {
355 return k;
356 }
357 }
358 #endif // INCLUDE_CDS
359
360 // Double-check, if child class is already loaded, just return super-class,interface
361 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
362 // dictionary.
363 // Make sure there's a placeholder for the *child* before resolving.
364 // Used as a claim that this thread is currently loading superclass/classloader
365 // Used here for ClassCircularity checks and also for heap verification
366 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
367 // Must check ClassCircularity before checking if super class is already loaded.
368 //
369 // We might not already have a placeholder if this child_name was
370 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
371 // the name of the class might not be known until the stream is actually
372 // parsed.
373 // Bugs 4643874, 4715493
374
375 ClassLoaderData* loader_data = class_loader_data(class_loader);
376 Dictionary* dictionary = loader_data->dictionary();
377 unsigned int d_hash = dictionary->compute_hash(child_name);
378 unsigned int p_hash = placeholders()->compute_hash(child_name);
379 int p_index = placeholders()->hash_to_index(p_hash);
380 // can't throw error holding a lock
381 bool child_already_loaded = false;
382 bool throw_circularity_error = false;
383 {
384 MutexLocker mu(SystemDictionary_lock, THREAD);
385 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
386 InstanceKlass* quicksuperk;
387 // to support // loading: if child done loading, just return superclass
388 // if super_name, & class_loader don't match:
389 // if initial define, SD update will give LinkageError
390 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
391 // so we don't throw an exception here.
392 // see: nsk redefclass014 & java.lang.instrument Instrument032
393 if ((childk != NULL ) && (is_superclass) &&
394 ((quicksuperk = childk->java_super()) != NULL) &&
395 ((quicksuperk->name() == super_name) &&
396 (quicksuperk->class_loader() == class_loader()))) {
397 return quicksuperk;
398 } else {
399 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
400 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
401 throw_circularity_error = true;
402 }
403 }
404 if (!throw_circularity_error) {
405 // Be careful not to exit resolve_super
406 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
407 }
408 }
409 if (throw_circularity_error) {
410 ResourceMark rm(THREAD);
411 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
412 }
413
414 // java.lang.Object should have been found above
415 assert(super_name != NULL, "null super class for resolving");
416 // Resolve the super class or interface, check results on return
417 InstanceKlass* superk =
418 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
419 class_loader,
420 protection_domain,
421 THREAD);
422
423 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
424 // It is no longer necessary to keep the placeholder table alive until update_dictionary
425 // or error. GC used to walk the placeholder table as strong roots.
426 // The instanceKlass is kept alive because the class loader is on the stack,
427 // which keeps the loader_data alive, as well as all instanceKlasses in
428 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
429 {
430 MutexLocker mu(SystemDictionary_lock, THREAD);
431 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
432 SystemDictionary_lock->notify_all();
433 }
434 if (HAS_PENDING_EXCEPTION || superk == NULL) {
435 // can null superk
436 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
437 assert(k == NULL || k == superk, "must be");
438 if (k == NULL) {
439 superk = NULL;
440 }
441 }
442
443 return superk;
444 }
445
446 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
447 Handle class_loader,
448 Handle protection_domain,
449 TRAPS) {
450 if(!has_checkPackageAccess()) return;
451
452 // Now we have to call back to java to check if the initating class has access
453 JavaValue result(T_VOID);
454 LogTarget(Debug, protectiondomain) lt;
455 if (lt.is_enabled()) {
456 ResourceMark rm;
457 // Print out trace information
458 LogStream ls(lt);
459 ls.print_cr("Checking package access");
460 if (class_loader() != NULL) {
461 ls.print("class loader: ");
462 class_loader()->print_value_on(&ls);
463 } else {
464 ls.print_cr("class loader: NULL");
465 }
466 if (protection_domain() != NULL) {
467 ls.print(" protection domain: ");
468 protection_domain()->print_value_on(&ls);
469 } else {
470 ls.print_cr(" protection domain: NULL");
471 }
472 ls.print(" loading: "); klass->print_value_on(&ls);
473 ls.cr();
474 }
475
476 // This handle and the class_loader handle passed in keeps this class from
477 // being unloaded through several GC points.
478 // The class_loader handle passed in is the initiating loader.
479 Handle mirror(THREAD, klass->java_mirror());
480
481 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
482 JavaCalls::call_special(&result,
483 class_loader,
484 system_loader,
485 vmSymbols::checkPackageAccess_name(),
486 vmSymbols::class_protectiondomain_signature(),
487 mirror,
488 protection_domain,
489 THREAD);
490
491 if (HAS_PENDING_EXCEPTION) {
492 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
493 } else {
494 log_debug(protectiondomain)("granted");
495 }
496
497 if (HAS_PENDING_EXCEPTION) return;
498
499 // If no exception has been thrown, we have validated the protection domain
500 // Insert the protection domain of the initiating class into the set.
501 {
502 ClassLoaderData* loader_data = class_loader_data(class_loader);
503 Dictionary* dictionary = loader_data->dictionary();
504
505 Symbol* kn = klass->name();
506 unsigned int d_hash = dictionary->compute_hash(kn);
507
508 MutexLocker mu(SystemDictionary_lock, THREAD);
509 int d_index = dictionary->hash_to_index(d_hash);
510 dictionary->add_protection_domain(d_index, d_hash, klass,
511 protection_domain, THREAD);
512 }
513 }
514
515 // We only get here if this thread finds that another thread
516 // has already claimed the placeholder token for the current operation,
517 // but that other thread either never owned or gave up the
518 // object lock
519 // Waits on SystemDictionary_lock to indicate placeholder table updated
520 // On return, caller must recheck placeholder table state
521 //
522 // We only get here if
523 // 1) custom classLoader, i.e. not bootstrap classloader
524 // 2) custom classLoader has broken the class loader objectLock
525 // so another thread got here in parallel
526 //
527 // lockObject must be held.
528 // Complicated dance due to lock ordering:
529 // Must first release the classloader object lock to
530 // allow initial definer to complete the class definition
531 // and to avoid deadlock
532 // Reclaim classloader lock object with same original recursion count
533 // Must release SystemDictionary_lock after notify, since
534 // class loader lock must be claimed before SystemDictionary_lock
535 // to prevent deadlocks
536 //
537 // The notify allows applications that did an untimed wait() on
538 // the classloader object lock to not hang.
539 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
540 assert_lock_strong(SystemDictionary_lock);
541
542 bool calledholdinglock
543 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
544 assert(calledholdinglock,"must hold lock for notify");
545 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
546 ObjectSynchronizer::notifyall(lockObject, THREAD);
547 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
548 SystemDictionary_lock->wait();
549 SystemDictionary_lock->unlock();
550 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
551 SystemDictionary_lock->lock();
552 }
553
554 // If the class in is in the placeholder table, class loading is in progress
555 // For cases where the application changes threads to load classes, it
556 // is critical to ClassCircularity detection that we try loading
557 // the superclass on the same thread internally, so we do parallel
558 // super class loading here.
559 // This also is critical in cases where the original thread gets stalled
560 // even in non-circularity situations.
561 // Note: must call resolve_super_or_fail even if null super -
562 // to force placeholder entry creation for this class for circularity detection
563 // Caller must check for pending exception
564 // Returns non-null Klass* if other thread has completed load
565 // and we are done,
566 // If return null Klass* and no pending exception, the caller must load the class
567 InstanceKlass* SystemDictionary::handle_parallel_super_load(
568 Symbol* name, Symbol* superclassname, Handle class_loader,
569 Handle protection_domain, Handle lockObject, TRAPS) {
570
571 ClassLoaderData* loader_data = class_loader_data(class_loader);
572 Dictionary* dictionary = loader_data->dictionary();
573 unsigned int d_hash = dictionary->compute_hash(name);
574 unsigned int p_hash = placeholders()->compute_hash(name);
575 int p_index = placeholders()->hash_to_index(p_hash);
576
577 // superk is not used, resolve_super called for circularity check only
578 // This code is reached in two situations. One if this thread
579 // is loading the same class twice (e.g. ClassCircularity, or
580 // java.lang.instrument).
581 // The second is if another thread started the resolve_super first
582 // and has not yet finished.
583 // In both cases the original caller will clean up the placeholder
584 // entry on error.
585 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
586 superclassname,
587 class_loader,
588 protection_domain,
589 true,
590 CHECK_NULL);
591
592 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
593 // Serial class loaders and bootstrap classloader do wait for superclass loads
594 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
595 MutexLocker mu(SystemDictionary_lock, THREAD);
596 // Check if classloading completed while we were loading superclass or waiting
597 return find_class(d_hash, name, dictionary);
598 }
599
600 // must loop to both handle other placeholder updates
601 // and spurious notifications
602 bool super_load_in_progress = true;
603 PlaceholderEntry* placeholder;
604 while (super_load_in_progress) {
605 MutexLocker mu(SystemDictionary_lock, THREAD);
606 // Check if classloading completed while we were loading superclass or waiting
607 InstanceKlass* check = find_class(d_hash, name, dictionary);
608 if (check != NULL) {
609 // Klass is already loaded, so just return it
610 return check;
611 } else {
612 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
613 if (placeholder && placeholder->super_load_in_progress() ){
614 // We only get here if the application has released the
615 // classloader lock when another thread was in the middle of loading a
616 // superclass/superinterface for this class, and now
617 // this thread is also trying to load this class.
618 // To minimize surprises, the first thread that started to
619 // load a class should be the one to complete the loading
620 // with the classfile it initially expected.
621 // This logic has the current thread wait once it has done
622 // all the superclass/superinterface loading it can, until
623 // the original thread completes the class loading or fails
624 // If it completes we will use the resulting InstanceKlass
625 // which we will find below in the systemDictionary.
626 // We also get here for parallel bootstrap classloader
627 if (class_loader.is_null()) {
628 SystemDictionary_lock->wait();
629 } else {
630 double_lock_wait(lockObject, THREAD);
631 }
632 } else {
633 // If not in SD and not in PH, other thread's load must have failed
634 super_load_in_progress = false;
635 }
636 }
637 }
638 return NULL;
639 }
640
641 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
642 assert(event != NULL, "invariant");
643 assert(k != NULL, "invariant");
644 assert(event->should_commit(), "invariant");
645 event->set_loadedClass(k);
646 event->set_definingClassLoader(k->class_loader_data());
647 event->set_initiatingClassLoader(init_cld);
648 event->commit();
649 }
650
651
652 // Be careful when modifying this code: once you have run
653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
654 // you need to find_and_remove it before returning.
655 // So be careful to not exit with a CHECK_ macro betweeen these calls.
656 //
657 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
658 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
659 Handle class_loader,
660 Handle protection_domain,
661 TRAPS) {
662 assert(name != NULL && !FieldType::is_array(name) &&
663 !FieldType::is_obj(name), "invalid class name");
664
665 EventClassLoad class_load_start_event;
666
667 HandleMark hm(THREAD);
668
669 // Fix for 4474172; see evaluation for more details
670 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
671 ClassLoaderData* loader_data = register_loader(class_loader);
672 Dictionary* dictionary = loader_data->dictionary();
673 unsigned int d_hash = dictionary->compute_hash(name);
674
675 // Do lookup to see if class already exist and the protection domain
676 // has the right access
677 // This call uses find which checks protection domain already matches
678 // All subsequent calls use find_class, and set has_loaded_class so that
679 // before we return a result we call out to java to check for valid protection domain
680 // to allow returning the Klass* and add it to the pd_set if it is valid
681 {
682 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
683 if (probe != NULL) return probe;
684 }
685
686 // Non-bootstrap class loaders will call out to class loader and
687 // define via jvm/jni_DefineClass which will acquire the
688 // class loader object lock to protect against multiple threads
689 // defining the class in parallel by accident.
690 // This lock must be acquired here so the waiter will find
691 // any successful result in the SystemDictionary and not attempt
692 // the define.
693 // ParallelCapable Classloaders and the bootstrap classloader
694 // do not acquire lock here.
695 bool DoObjectLock = true;
696 if (is_parallelCapable(class_loader)) {
697 DoObjectLock = false;
698 }
699
700 unsigned int p_hash = placeholders()->compute_hash(name);
701 int p_index = placeholders()->hash_to_index(p_hash);
702
703 // Class is not in SystemDictionary so we have to do loading.
704 // Make sure we are synchronized on the class loader before we proceed
705 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
706 check_loader_lock_contention(lockObject, THREAD);
707 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
708
709 // Check again (after locking) if class already exist in SystemDictionary
710 bool class_has_been_loaded = false;
711 bool super_load_in_progress = false;
712 bool havesupername = false;
713 InstanceKlass* k = NULL;
714 PlaceholderEntry* placeholder;
715 Symbol* superclassname = NULL;
716
717 assert(THREAD->can_call_java(),
718 "can not load classes with compiler thread: class=%s, classloader=%s",
719 name->as_C_string(),
720 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
721 {
722 MutexLocker mu(SystemDictionary_lock, THREAD);
723 InstanceKlass* check = find_class(d_hash, name, dictionary);
724 if (check != NULL) {
725 // InstanceKlass is already loaded, so just return it
726 class_has_been_loaded = true;
727 k = check;
728 } else {
729 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
730 if (placeholder && placeholder->super_load_in_progress()) {
731 super_load_in_progress = true;
732 if (placeholder->havesupername() == true) {
733 superclassname = placeholder->supername();
734 havesupername = true;
735 }
736 }
737 }
738 }
739
740 // If the class is in the placeholder table, class loading is in progress
741 if (super_load_in_progress && havesupername==true) {
742 k = handle_parallel_super_load(name,
743 superclassname,
744 class_loader,
745 protection_domain,
746 lockObject, THREAD);
747 if (HAS_PENDING_EXCEPTION) {
748 return NULL;
749 }
750 if (k != NULL) {
751 class_has_been_loaded = true;
752 }
753 }
754
755 bool throw_circularity_error = false;
756 if (!class_has_been_loaded) {
757 bool load_instance_added = false;
758
759 // add placeholder entry to record loading instance class
760 // Five cases:
761 // All cases need to prevent modifying bootclasssearchpath
762 // in parallel with a classload of same classname
763 // Redefineclasses uses existence of the placeholder for the duration
764 // of the class load to prevent concurrent redefinition of not completely
765 // defined classes.
766 // case 1. traditional classloaders that rely on the classloader object lock
767 // - no other need for LOAD_INSTANCE
768 // case 2. traditional classloaders that break the classloader object lock
769 // as a deadlock workaround. Detection of this case requires that
770 // this check is done while holding the classloader object lock,
771 // and that lock is still held when calling classloader's loadClass.
772 // For these classloaders, we ensure that the first requestor
773 // completes the load and other requestors wait for completion.
774 // case 3. Bootstrap classloader - don't own objectLocker
775 // This classloader supports parallelism at the classloader level,
776 // but only allows a single load of a class/classloader pair.
777 // No performance benefit and no deadlock issues.
778 // case 4. parallelCapable user level classloaders - without objectLocker
779 // Allow parallel classloading of a class/classloader pair
780
781 {
782 MutexLocker mu(SystemDictionary_lock, THREAD);
783 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
784 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
785 if (oldprobe) {
786 // only need check_seen_thread once, not on each loop
787 // 6341374 java/lang/Instrument with -Xcomp
788 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
789 throw_circularity_error = true;
790 } else {
791 // case 1: traditional: should never see load_in_progress.
792 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
793
794 // case 3: bootstrap classloader: prevent futile classloading,
795 // wait on first requestor
796 if (class_loader.is_null()) {
797 SystemDictionary_lock->wait();
798 } else {
799 // case 2: traditional with broken classloader lock. wait on first
800 // requestor.
801 double_lock_wait(lockObject, THREAD);
802 }
803 // Check if classloading completed while we were waiting
804 InstanceKlass* check = find_class(d_hash, name, dictionary);
805 if (check != NULL) {
806 // Klass is already loaded, so just return it
807 k = check;
808 class_has_been_loaded = true;
809 }
810 // check if other thread failed to load and cleaned up
811 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
812 }
813 }
814 }
815 }
816 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
817 // case 4: parallelCapable: allow competing threads to try
818 // LOAD_INSTANCE in parallel
819
820 if (!throw_circularity_error && !class_has_been_loaded) {
821 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
822 load_instance_added = true;
823 // For class loaders that do not acquire the classloader object lock,
824 // if they did not catch another thread holding LOAD_INSTANCE,
825 // need a check analogous to the acquire ObjectLocker/find_class
826 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
827 // one final check if the load has already completed
828 // class loaders holding the ObjectLock shouldn't find the class here
829 InstanceKlass* check = find_class(d_hash, name, dictionary);
830 if (check != NULL) {
831 // Klass is already loaded, so return it after checking/adding protection domain
832 k = check;
833 class_has_been_loaded = true;
834 }
835 }
836 }
837
838 // must throw error outside of owning lock
839 if (throw_circularity_error) {
840 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
841 ResourceMark rm(THREAD);
842 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
843 }
844
845 if (!class_has_been_loaded) {
846
847 // Do actual loading
848 k = load_instance_class(name, class_loader, THREAD);
849
850 // If everything was OK (no exceptions, no null return value), and
851 // class_loader is NOT the defining loader, do a little more bookkeeping.
852 if (!HAS_PENDING_EXCEPTION && k != NULL &&
853 k->class_loader() != class_loader()) {
854
855 check_constraints(d_hash, k, class_loader, false, THREAD);
856
857 // Need to check for a PENDING_EXCEPTION again; check_constraints
858 // can throw but we may have to remove entry from the placeholder table below.
859 if (!HAS_PENDING_EXCEPTION) {
860 // Record dependency for non-parent delegation.
861 // This recording keeps the defining class loader of the klass (k) found
862 // from being unloaded while the initiating class loader is loaded
863 // even if the reference to the defining class loader is dropped
864 // before references to the initiating class loader.
865 loader_data->record_dependency(k);
866
867 { // Grabbing the Compile_lock prevents systemDictionary updates
868 // during compilations.
869 MutexLocker mu(Compile_lock, THREAD);
870 update_dictionary(d_hash, p_index, p_hash,
871 k, class_loader, THREAD);
872 }
873
874 if (JvmtiExport::should_post_class_load()) {
875 Thread *thread = THREAD;
876 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
877 JvmtiExport::post_class_load((JavaThread *) thread, k);
878 }
879 }
880 }
881 } // load_instance_class
882
883 if (load_instance_added == true) {
884 // clean up placeholder entries for LOAD_INSTANCE success or error
885 // This brackets the SystemDictionary updates for both defining
886 // and initiating loaders
887 MutexLocker mu(SystemDictionary_lock, THREAD);
888 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
889 SystemDictionary_lock->notify_all();
890 }
891 }
892
893 if (HAS_PENDING_EXCEPTION || k == NULL) {
894 return NULL;
895 }
896 if (class_load_start_event.should_commit()) {
897 post_class_load_event(&class_load_start_event, k, loader_data);
898 }
899 #ifdef ASSERT
900 {
901 ClassLoaderData* loader_data = k->class_loader_data();
902 MutexLocker mu(SystemDictionary_lock, THREAD);
903 InstanceKlass* kk = find_class(name, loader_data);
904 assert(kk == k, "should be present in dictionary");
905 }
906 #endif
907
908 // return if the protection domain in NULL
909 if (protection_domain() == NULL) return k;
910
911 // Check the protection domain has the right access
912 if (dictionary->is_valid_protection_domain(d_hash, name,
913 protection_domain)) {
914 return k;
915 }
916
917 // Verify protection domain. If it fails an exception is thrown
918 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
919
920 return k;
921 }
922
923
924 // This routine does not lock the system dictionary.
925 //
926 // Since readers don't hold a lock, we must make sure that system
927 // dictionary entries are only removed at a safepoint (when only one
928 // thread is running), and are added to in a safe way (all links must
929 // be updated in an MT-safe manner).
930 //
931 // Callers should be aware that an entry could be added just after
932 // _dictionary->bucket(index) is read here, so the caller will not see
933 // the new entry.
934
935 Klass* SystemDictionary::find(Symbol* class_name,
936 Handle class_loader,
937 Handle protection_domain,
938 TRAPS) {
939
940 // The result of this call should be consistent with the result
941 // of the call to resolve_instance_class_or_null().
942 // See evaluation 6790209 and 4474172 for more details.
943 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
944 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
945
946 if (loader_data == NULL) {
947 // If the ClassLoaderData has not been setup,
948 // then the class loader has no entries in the dictionary.
949 return NULL;
950 }
951
952 Dictionary* dictionary = loader_data->dictionary();
953 unsigned int d_hash = dictionary->compute_hash(class_name);
954 return dictionary->find(d_hash, class_name,
955 protection_domain);
956 }
957
958
959 // Look for a loaded instance or array klass by name. Do not do any loading.
960 // return NULL in case of error.
961 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
962 Handle class_loader,
963 Handle protection_domain,
964 TRAPS) {
965 Klass* k = NULL;
966 assert(class_name != NULL, "class name must be non NULL");
967
968 if (FieldType::is_array(class_name)) {
969 // The name refers to an array. Parse the name.
970 // dimension and object_key in FieldArrayInfo are assigned as a
971 // side-effect of this call
972 FieldArrayInfo fd;
973 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
974 if (t != T_OBJECT) {
975 k = Universe::typeArrayKlassObj(t);
976 } else {
977 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
978 }
979 if (k != NULL) {
980 k = k->array_klass_or_null(fd.dimension());
981 }
982 } else {
983 k = find(class_name, class_loader, protection_domain, THREAD);
984 }
985 return k;
986 }
987
988 // Note: this method is much like resolve_from_stream, but
989 // does not publish the classes via the SystemDictionary.
990 // Handles unsafe_DefineAnonymousClass and redefineclasses
991 // RedefinedClasses do not add to the class hierarchy
992 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
993 Handle class_loader,
994 Handle protection_domain,
995 ClassFileStream* st,
996 const InstanceKlass* unsafe_anonymous_host,
997 GrowableArray<Handle>* cp_patches,
998 TRAPS) {
999
1000 EventClassLoad class_load_start_event;
1001
1002 ClassLoaderData* loader_data;
1003 if (unsafe_anonymous_host != NULL) {
1004 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1005 // as the unsafe_anonymous_host
1006 guarantee(unsafe_anonymous_host->class_loader() == class_loader(), "should be the same");
1007 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1008 } else {
1009 loader_data = ClassLoaderData::class_loader_data(class_loader());
1010 }
1011
1012 assert(st != NULL, "invariant");
1013 assert(st->need_verify(), "invariant");
1014
1015 // Parse stream and create a klass.
1016 // Note that we do this even though this klass might
1017 // already be present in the SystemDictionary, otherwise we would not
1018 // throw potential ClassFormatErrors.
1019
1020 InstanceKlass* k = KlassFactory::create_from_stream(st,
1021 class_name,
1022 loader_data,
1023 protection_domain,
1024 unsafe_anonymous_host,
1025 cp_patches,
1026 CHECK_NULL);
1027
1028 if (unsafe_anonymous_host != NULL && k != NULL) {
1029 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1030 // so that they can be unloaded when the mirror is no longer referenced.
1031 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1032
1033 {
1034 MutexLocker mu_r(Compile_lock, THREAD);
1035
1036 // Add to class hierarchy, initialize vtables, and do possible
1037 // deoptimizations.
1038 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1039 // But, do not add to dictionary.
1040 }
1041
1042 // Rewrite and patch constant pool here.
1043 k->link_class(CHECK_NULL);
1044 if (cp_patches != NULL) {
1045 k->constants()->patch_resolved_references(cp_patches);
1046 }
1047
1048 // If it's anonymous, initialize it now, since nobody else will.
1049 k->eager_initialize(CHECK_NULL);
1050
1051 // notify jvmti
1052 if (JvmtiExport::should_post_class_load()) {
1053 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1054 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1055 }
1056 if (class_load_start_event.should_commit()) {
1057 post_class_load_event(&class_load_start_event, k, loader_data);
1058 }
1059 }
1060 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1061 "cp_patches only found with unsafe_anonymous_host");
1062
1063 return k;
1064 }
1065
1066 // Add a klass to the system from a stream (called by jni_DefineClass and
1067 // JVM_DefineClass).
1068 // Note: class_name can be NULL. In that case we do not know the name of
1069 // the class until we have parsed the stream.
1070
1071 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1072 Handle class_loader,
1073 Handle protection_domain,
1074 ClassFileStream* st,
1075 TRAPS) {
1076
1077 HandleMark hm(THREAD);
1078
1079 // Classloaders that support parallelism, e.g. bootstrap classloader,
1080 // do not acquire lock here
1081 bool DoObjectLock = true;
1082 if (is_parallelCapable(class_loader)) {
1083 DoObjectLock = false;
1084 }
1085
1086 ClassLoaderData* loader_data = register_loader(class_loader);
1087
1088 // Make sure we are synchronized on the class loader before we proceed
1089 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1090 check_loader_lock_contention(lockObject, THREAD);
1091 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1092
1093 assert(st != NULL, "invariant");
1094
1095 // Parse the stream and create a klass.
1096 // Note that we do this even though this klass might
1097 // already be present in the SystemDictionary, otherwise we would not
1098 // throw potential ClassFormatErrors.
1099 InstanceKlass* k = NULL;
1100
1101 #if INCLUDE_CDS
1102 if (!DumpSharedSpaces) {
1103 k = SystemDictionaryShared::lookup_from_stream(class_name,
1104 class_loader,
1105 protection_domain,
1106 st,
1107 CHECK_NULL);
1108 }
1109 #endif
1110
1111 if (k == NULL) {
1112 if (st->buffer() == NULL) {
1113 return NULL;
1114 }
1115 k = KlassFactory::create_from_stream(st,
1116 class_name,
1117 loader_data,
1118 protection_domain,
1119 NULL, // unsafe_anonymous_host
1120 NULL, // cp_patches
1121 CHECK_NULL);
1122 }
1123
1124 assert(k != NULL, "no klass created");
1125 Symbol* h_name = k->name();
1126 assert(class_name == NULL || class_name == h_name, "name mismatch");
1127
1128 // Add class just loaded
1129 // If a class loader supports parallel classloading handle parallel define requests
1130 // find_or_define_instance_class may return a different InstanceKlass
1131 if (is_parallelCapable(class_loader)) {
1132 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1133 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1134 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1135 assert(defined_k != NULL, "Should have a klass if there's no exception");
1136 loader_data->add_to_deallocate_list(k);
1137 k = defined_k;
1138 }
1139 } else {
1140 define_instance_class(k, THREAD);
1141 }
1142
1143 // If defining the class throws an exception register 'k' for cleanup.
1144 if (HAS_PENDING_EXCEPTION) {
1145 assert(k != NULL, "Must have an instance klass here!");
1146 loader_data->add_to_deallocate_list(k);
1147 return NULL;
1148 }
1149
1150 // Make sure we have an entry in the SystemDictionary on success
1151 debug_only( {
1152 MutexLocker mu(SystemDictionary_lock, THREAD);
1153
1154 Klass* check = find_class(h_name, k->class_loader_data());
1155 assert(check == k, "should be present in the dictionary");
1156 } );
1157
1158 return k;
1159 }
1160
1161 #if INCLUDE_CDS
1162 // Load a class for boot loader from the shared spaces. This also
1163 // forces the super class and all interfaces to be loaded.
1164 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1165 TRAPS) {
1166 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1167 if (ik != NULL && ik->is_shared_boot_class()) {
1168 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1169 }
1170 return NULL;
1171 }
1172
1173 // Check if a shared class can be loaded by the specific classloader:
1174 //
1175 // NULL classloader:
1176 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1177 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1178 // be defined in an unnamed module.
1179 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1180 InstanceKlass* ik,
1181 Handle class_loader, TRAPS) {
1182 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1183 "Cannot use sharing if java.base is patched");
1184 ResourceMark rm;
1185 int path_index = ik->shared_classpath_index();
1186 ClassLoaderData* loader_data = class_loader_data(class_loader);
1187 if (path_index < 0) {
1188 // path_index < 0 indicates that the class is intended for a custom loader
1189 // and should not be loaded by boot/platform/app loaders
1190 if (loader_data->is_builtin_class_loader_data()) {
1191 return false;
1192 } else {
1193 return true;
1194 }
1195 }
1196 SharedClassPathEntry* ent =
1197 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1198 if (!Universe::is_module_initialized()) {
1199 assert(ent != NULL && ent->is_modules_image(),
1200 "Loading non-bootstrap classes before the module system is initialized");
1201 assert(class_loader.is_null(), "sanity");
1202 return true;
1203 }
1204 // Get the pkg_entry from the classloader
1205 TempNewSymbol pkg_name = NULL;
1206 PackageEntry* pkg_entry = NULL;
1207 ModuleEntry* mod_entry = NULL;
1208 const char* pkg_string = NULL;
1209 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1210 if (pkg_name != NULL) {
1211 pkg_string = pkg_name->as_C_string();
1212 if (loader_data != NULL) {
1213 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1214 }
1215 if (pkg_entry != NULL) {
1216 mod_entry = pkg_entry->module();
1217 }
1218 }
1219
1220 // If the archived class is from a module that has been patched at runtime,
1221 // the class cannot be loaded from the archive.
1222 if (mod_entry != NULL && mod_entry->is_patched()) {
1223 return false;
1224 }
1225
1226 if (class_loader.is_null()) {
1227 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1228 // The NULL classloader can load archived class originated from the
1229 // "modules" jimage and the -Xbootclasspath/a. For class from the
1230 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1231 // by the NULL classloader.
1232 if (mod_entry != NULL) {
1233 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1234 // ModuleEntry's location agrees with the archived class' origination.
1235 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1236 return true; // Module class from the "module" jimage
1237 }
1238 }
1239
1240 // If the archived class is not from the "module" jimage, the class can be
1241 // loaded by the NULL classloader if
1242 //
1243 // 1. the class is from the unamed package
1244 // 2. or, the class is not from a module defined in the NULL classloader
1245 // 3. or, the class is from an unamed module
1246 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1247 // the class is from the -Xbootclasspath/a
1248 if (pkg_string == NULL ||
1249 pkg_entry == NULL ||
1250 pkg_entry->in_unnamed_module()) {
1251 assert(mod_entry == NULL ||
1252 mod_entry == loader_data->unnamed_module(),
1253 "the unnamed module is not defined in the classloader");
1254 return true;
1255 }
1256 }
1257 return false;
1258 } else {
1259 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1260 ik, class_loader, pkg_string, pkg_name,
1261 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;
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 ResourceMark rm;
1377 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1378 }
1379 }
1380
1381 return ik;
1382 }
1383 #endif // INCLUDE_CDS
1384
1385 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1386
1387 if (class_loader.is_null()) {
1388 ResourceMark rm;
1389 PackageEntry* pkg_entry = NULL;
1390 bool search_only_bootloader_append = false;
1391 ClassLoaderData *loader_data = class_loader_data(class_loader);
1392
1393 // Find the package in the boot loader's package entry table.
1394 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1395 if (pkg_name != NULL) {
1396 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1397 }
1398
1399 // Prior to attempting to load the class, enforce the boot loader's
1400 // visibility boundaries.
1401 if (!Universe::is_module_initialized()) {
1402 // During bootstrapping, prior to module initialization, any
1403 // class attempting to be loaded must be checked against the
1404 // java.base packages in the boot loader's PackageEntryTable.
1405 // No class outside of java.base is allowed to be loaded during
1406 // this bootstrapping window.
1407 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1408 // Class is either in the unnamed package or in
1409 // a named package within the unnamed module. Either
1410 // case is outside of java.base, do not attempt to
1411 // load the class post java.base definition. If
1412 // java.base has not been defined, let the class load
1413 // and its package will be checked later by
1414 // ModuleEntryTable::verify_javabase_packages.
1415 if (ModuleEntryTable::javabase_defined()) {
1416 return NULL;
1417 }
1418 } else {
1419 // Check that the class' package is defined within java.base.
1420 ModuleEntry* mod_entry = pkg_entry->module();
1421 Symbol* mod_entry_name = mod_entry->name();
1422 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1423 return NULL;
1424 }
1425 }
1426 } else {
1427 // After the module system has been initialized, check if the class'
1428 // package is in a module defined to the boot loader.
1429 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1430 // Class is either in the unnamed package, in a named package
1431 // within a module not defined to the boot loader or in a
1432 // a named package within the unnamed module. In all cases,
1433 // limit visibility to search for the class only in the boot
1434 // loader's append path.
1435 search_only_bootloader_append = true;
1436 }
1437 }
1438
1439 // Prior to bootstrapping's module initialization, never load a class outside
1440 // of the boot loader's module path
1441 assert(Universe::is_module_initialized() ||
1442 !search_only_bootloader_append,
1443 "Attempt to load a class outside of boot loader's module path");
1444
1445 // Search for classes in the CDS archive.
1446 InstanceKlass* k = NULL;
1447 {
1448 #if INCLUDE_CDS
1449 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1450 k = load_shared_boot_class(class_name, THREAD);
1451 #endif
1452 }
1453
1454 if (k == NULL) {
1455 // Use VM class loader
1456 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1457 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1458 }
1459
1460 // find_or_define_instance_class may return a different InstanceKlass
1461 if (k != NULL) {
1462 InstanceKlass* defined_k =
1463 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1464 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1465 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1466 assert(defined_k != NULL, "Should have a klass if there's no exception");
1467 loader_data->add_to_deallocate_list(k);
1468 k = defined_k;
1469 } else if (HAS_PENDING_EXCEPTION) {
1470 loader_data->add_to_deallocate_list(k);
1471 return NULL;
1472 }
1473 }
1474 return k;
1475 } else {
1476 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1477 ResourceMark rm(THREAD);
1478
1479 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1480 JavaThread* jt = (JavaThread*) THREAD;
1481
1482 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1483 ClassLoader::perf_app_classload_selftime(),
1484 ClassLoader::perf_app_classload_count(),
1485 jt->get_thread_stat()->perf_recursion_counts_addr(),
1486 jt->get_thread_stat()->perf_timers_addr(),
1487 PerfClassTraceTime::CLASS_LOAD);
1488
1489 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1490 // Translate to external class name format, i.e., convert '/' chars to '.'
1491 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1492
1493 JavaValue result(T_OBJECT);
1494
1495 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1496
1497 // Call public unsynchronized loadClass(String) directly for all class loaders.
1498 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1499 // acquire a class-name based lock rather than the class loader object lock.
1500 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1501 JavaCalls::call_virtual(&result,
1502 class_loader,
1503 spec_klass,
1504 vmSymbols::loadClass_name(),
1505 vmSymbols::string_class_signature(),
1506 string,
1507 CHECK_NULL);
1508
1509 assert(result.get_type() == T_OBJECT, "just checking");
1510 oop obj = (oop) result.get_jobject();
1511
1512 // Primitive classes return null since forName() can not be
1513 // used to obtain any of the Class objects representing primitives or void
1514 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1515 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1516 // For user defined Java class loaders, check that the name returned is
1517 // the same as that requested. This check is done for the bootstrap
1518 // loader when parsing the class file.
1519 if (class_name == k->name()) {
1520 return k;
1521 }
1522 }
1523 // Class is not found or has the wrong name, return NULL
1524 return NULL;
1525 }
1526 }
1527
1528 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1529 EventClassDefine event;
1530 if (event.should_commit()) {
1531 event.set_definedClass(k);
1532 event.set_definingClassLoader(def_cld);
1533 event.commit();
1534 }
1535 }
1536
1537 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1538
1539 HandleMark hm(THREAD);
1540 ClassLoaderData* loader_data = k->class_loader_data();
1541 Handle class_loader_h(THREAD, loader_data->class_loader());
1542
1543 // for bootstrap and other parallel classloaders don't acquire lock,
1544 // use placeholder token
1545 // If a parallelCapable class loader calls define_instance_class instead of
1546 // find_or_define_instance_class to get here, we have a timing
1547 // hole with systemDictionary updates and check_constraints
1548 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1549 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1550 compute_loader_lock_object(class_loader_h, THREAD)),
1551 "define called without lock");
1552 }
1553
1554 // Check class-loading constraints. Throw exception if violation is detected.
1555 // Grabs and releases SystemDictionary_lock
1556 // The check_constraints/find_class call and update_dictionary sequence
1557 // must be "atomic" for a specific class/classloader pair so we never
1558 // define two different instanceKlasses for that class/classloader pair.
1559 // Existing classloaders will call define_instance_class with the
1560 // classloader lock held
1561 // Parallel classloaders will call find_or_define_instance_class
1562 // which will require a token to perform the define class
1563 Symbol* name_h = k->name();
1564 Dictionary* dictionary = loader_data->dictionary();
1565 unsigned int d_hash = dictionary->compute_hash(name_h);
1566 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1567
1568 // Register class just loaded with class loader (placed in Vector)
1569 // Note we do this before updating the dictionary, as this can
1570 // fail with an OutOfMemoryError (if it does, we will *not* put this
1571 // class in the dictionary and will not update the class hierarchy).
1572 // JVMTI FollowReferences needs to find the classes this way.
1573 if (k->class_loader() != NULL) {
1574 methodHandle m(THREAD, Universe::loader_addClass_method());
1575 JavaValue result(T_VOID);
1576 JavaCallArguments args(class_loader_h);
1577 args.push_oop(Handle(THREAD, k->java_mirror()));
1578 JavaCalls::call(&result, m, &args, CHECK);
1579 }
1580
1581 // Add the new class. We need recompile lock during update of CHA.
1582 {
1583 unsigned int p_hash = placeholders()->compute_hash(name_h);
1584 int p_index = placeholders()->hash_to_index(p_hash);
1585
1586 MutexLocker mu_r(Compile_lock, THREAD);
1587
1588 // Add to class hierarchy, initialize vtables, and do possible
1589 // deoptimizations.
1590 add_to_hierarchy(k, CHECK); // No exception, but can block
1591
1592 // Add to systemDictionary - so other classes can see it.
1593 // Grabs and releases SystemDictionary_lock
1594 update_dictionary(d_hash, p_index, p_hash,
1595 k, class_loader_h, THREAD);
1596 }
1597 k->eager_initialize(THREAD);
1598
1599 // notify jvmti
1600 if (JvmtiExport::should_post_class_load()) {
1601 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1602 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1603
1604 }
1605 post_class_define_event(k, loader_data);
1606 }
1607
1608 // Support parallel classloading
1609 // All parallel class loaders, including bootstrap classloader
1610 // lock a placeholder entry for this class/class_loader pair
1611 // to allow parallel defines of different classes for this class loader
1612 // With AllowParallelDefine flag==true, in case they do not synchronize around
1613 // FindLoadedClass/DefineClass, calls, we check for parallel
1614 // loading for them, wait if a defineClass is in progress
1615 // and return the initial requestor's results
1616 // This flag does not apply to the bootstrap classloader.
1617 // With AllowParallelDefine flag==false, call through to define_instance_class
1618 // which will throw LinkageError: duplicate class definition.
1619 // False is the requested default.
1620 // For better performance, the class loaders should synchronize
1621 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1622 // potentially waste time reading and parsing the bytestream.
1623 // Note: VM callers should ensure consistency of k/class_name,class_loader
1624 // Be careful when modifying this code: once you have run
1625 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1626 // you need to find_and_remove it before returning.
1627 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1628 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1629 InstanceKlass* k, TRAPS) {
1630
1631 Symbol* name_h = k->name(); // passed in class_name may be null
1632 ClassLoaderData* loader_data = class_loader_data(class_loader);
1633 Dictionary* dictionary = loader_data->dictionary();
1634
1635 unsigned int d_hash = dictionary->compute_hash(name_h);
1636
1637 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1638 unsigned int p_hash = placeholders()->compute_hash(name_h);
1639 int p_index = placeholders()->hash_to_index(p_hash);
1640 PlaceholderEntry* probe;
1641
1642 {
1643 MutexLocker mu(SystemDictionary_lock, THREAD);
1644 // First check if class already defined
1645 if (is_parallelDefine(class_loader)) {
1646 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1647 if (check != NULL) {
1648 return check;
1649 }
1650 }
1651
1652 // Acquire define token for this class/classloader
1653 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1654 // Wait if another thread defining in parallel
1655 // All threads wait - even those that will throw duplicate class: otherwise
1656 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1657 // if other thread has not finished updating dictionary
1658 while (probe->definer() != NULL) {
1659 SystemDictionary_lock->wait();
1660 }
1661 // Only special cases allow parallel defines and can use other thread's results
1662 // Other cases fall through, and may run into duplicate defines
1663 // caught by finding an entry in the SystemDictionary
1664 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1665 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1666 SystemDictionary_lock->notify_all();
1667 #ifdef ASSERT
1668 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1669 assert(check != NULL, "definer missed recording success");
1670 #endif
1671 return probe->instance_klass();
1672 } else {
1673 // This thread will define the class (even if earlier thread tried and had an error)
1674 probe->set_definer(THREAD);
1675 }
1676 }
1677
1678 define_instance_class(k, THREAD);
1679
1680 Handle linkage_exception = Handle(); // null handle
1681
1682 // definer must notify any waiting threads
1683 {
1684 MutexLocker mu(SystemDictionary_lock, THREAD);
1685 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1686 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1687 if (probe != NULL) {
1688 if (HAS_PENDING_EXCEPTION) {
1689 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1690 CLEAR_PENDING_EXCEPTION;
1691 } else {
1692 probe->set_instance_klass(k);
1693 }
1694 probe->set_definer(NULL);
1695 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1696 SystemDictionary_lock->notify_all();
1697 }
1698 }
1699
1700 // Can't throw exception while holding lock due to rank ordering
1701 if (linkage_exception() != NULL) {
1702 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1703 }
1704
1705 return k;
1706 }
1707
1708 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1709 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1710 if (class_loader.is_null()) {
1711 return Handle(THREAD, _system_loader_lock_obj);
1712 } else {
1713 return class_loader;
1714 }
1715 }
1716
1717 // This method is added to check how often we have to wait to grab loader
1718 // lock. The results are being recorded in the performance counters defined in
1719 // ClassLoader::_sync_systemLoaderLockContentionRate and
1720 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1721 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1722 if (!UsePerfData) {
1723 return;
1724 }
1725
1726 assert(!loader_lock.is_null(), "NULL lock object");
1727
1728 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1729 == ObjectSynchronizer::owner_other) {
1730 // contention will likely happen, so increment the corresponding
1731 // contention counter.
1732 if (loader_lock() == _system_loader_lock_obj) {
1733 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1734 } else {
1735 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1736 }
1737 }
1738 }
1739
1740 // ----------------------------------------------------------------------------
1741 // Lookup
1742
1743 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1744 Symbol* class_name,
1745 Dictionary* dictionary) {
1746 assert_locked_or_safepoint(SystemDictionary_lock);
1747 int index = dictionary->hash_to_index(hash);
1748 return dictionary->find_class(index, hash, class_name);
1749 }
1750
1751
1752 // Basic find on classes in the midst of being loaded
1753 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1754 ClassLoaderData* loader_data) {
1755 assert_locked_or_safepoint(SystemDictionary_lock);
1756 unsigned int p_hash = placeholders()->compute_hash(class_name);
1757 int p_index = placeholders()->hash_to_index(p_hash);
1758 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1759 }
1760
1761
1762 // Used for assertions and verification only
1763 // Precalculating the hash and index is an optimization because there are many lookups
1764 // before adding the class.
1765 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1766 assert_locked_or_safepoint(SystemDictionary_lock);
1767 #ifndef ASSERT
1768 guarantee(VerifyBeforeGC ||
1769 VerifyDuringGC ||
1770 VerifyBeforeExit ||
1771 VerifyDuringStartup ||
1772 VerifyAfterGC, "too expensive");
1773 #endif
1774
1775 Dictionary* dictionary = loader_data->dictionary();
1776 unsigned int d_hash = dictionary->compute_hash(class_name);
1777 return find_class(d_hash, class_name, dictionary);
1778 }
1779
1780
1781 // ----------------------------------------------------------------------------
1782 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1783 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1784 // before a new class is used.
1785
1786 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1787 assert(k != NULL, "just checking");
1788 assert_locked_or_safepoint(Compile_lock);
1789
1790 k->set_init_state(InstanceKlass::loaded);
1791 // make sure init_state store is already done.
1792 // The compiler reads the hierarchy outside of the Compile_lock.
1793 // Access ordering is used to add to hierarchy.
1794
1795 // Link into hierachy.
1796 k->append_to_sibling_list(); // add to superklass/sibling list
1797 k->process_interfaces(THREAD); // handle all "implements" declarations
1798
1799 // Now flush all code that depended on old class hierarchy.
1800 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1801 CodeCache::flush_dependents_on(k);
1802 }
1803
1804 // ----------------------------------------------------------------------------
1805 // GC support
1806
1807 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1808 // Note: anonymous classes are not in the SD.
1809 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1810
1811 bool unloading_occurred;
1812 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1813 {
1814 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1815 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1816 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1817 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1818 if (unloading_occurred) {
1819 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1820 JFR_ONLY(Jfr::on_unloading_classes();)
1821
1822 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1823 ClassLoaderDataGraph::clean_module_and_package_info();
1824 constraints()->purge_loader_constraints();
1825 resolution_errors()->purge_resolution_errors();
1826 }
1827 }
1828
1829 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1830
1831 if (unloading_occurred) {
1832 SymbolTable::trigger_cleanup();
1833
1834 // Oops referenced by the protection domain cache table may get unreachable independently
1835 // of the class loader (eg. cached protection domain oops). So we need to
1836 // explicitly unlink them here.
1837 // All protection domain oops are linked to the caller class, so if nothing
1838 // unloads, this is not needed.
1839 _pd_cache_table->trigger_cleanup();
1840 }
1841
1842 return unloading_occurred;
1843 }
1844
1845 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1846 f->do_oop(&_java_system_loader);
1847 f->do_oop(&_java_platform_loader);
1848 f->do_oop(&_system_loader_lock_obj);
1849 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1850
1851 // Visit extra methods
1852 invoke_method_table()->oops_do(f);
1853
1854 if (include_handles) {
1855 OopStorageSet::vm_global()->oops_do(f);
1856 }
1857 }
1858
1859 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1860 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1861 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1862 it->push(well_known_klass_addr((WKID)id));
1863 }
1864 }
1865
1866 void SystemDictionary::methods_do(void f(Method*)) {
1867 // Walk methods in loaded classes
1868 MutexLocker ml(ClassLoaderDataGraph_lock);
1869 ClassLoaderDataGraph::methods_do(f);
1870 // Walk method handle intrinsics
1871 invoke_method_table()->methods_do(f);
1872 }
1873
1874 // ----------------------------------------------------------------------------
1875 // Initialization
1876
1877 void SystemDictionary::initialize(TRAPS) {
1878 // Allocate arrays
1879 _placeholders = new PlaceholderTable(_placeholder_table_size);
1880 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1881 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1882 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1883 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1884
1885 // Allocate private object used as system class loader lock
1886 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1887 // Initialize basic classes
1888 resolve_well_known_classes(CHECK);
1889 }
1890
1891 // Compact table of directions on the initialization of klasses:
1892 static const short wk_init_info[] = {
1893 #define WK_KLASS_INIT_INFO(name, symbol) \
1894 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1895
1896 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1897 #undef WK_KLASS_INIT_INFO
1898 0
1899 };
1900
1901 #ifdef ASSERT
1902 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1903 int sid;
1904 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1905 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1906 if (class_name == symbol) {
1907 return true;
1908 }
1909 }
1910 return false;
1911 }
1912 #endif
1913
1914 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1915 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1916 int sid = wk_init_info[id - FIRST_WKID];
1917 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1918 InstanceKlass** klassp = &_well_known_klasses[id];
1919
1920 if ((*klassp) == NULL) {
1921 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1922 (*klassp) = InstanceKlass::cast(k);
1923 }
1924 return ((*klassp) != NULL);
1925 }
1926
1927 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1928 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1929 for (int id = (int)start_id; id < (int)limit_id; id++) {
1930 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1931 resolve_wk_klass((WKID)id, CHECK);
1932 }
1933
1934 // move the starting value forward to the limit:
1935 start_id = limit_id;
1936 }
1937
1938 void SystemDictionary::resolve_well_known_classes(TRAPS) {
1939 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
1940
1941 // Create the ModuleEntry for java.base. This call needs to be done here,
1942 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1943 ClassLoader::classLoader_init2(CHECK);
1944
1945 // Preload commonly used klasses
1946 WKID scan = FIRST_WKID;
1947 // first do Object, then String, Class
1948 #if INCLUDE_CDS
1949 if (UseSharedSpaces) {
1950 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1951
1952 // It's unsafe to access the archived heap regions before they
1953 // are fixed up, so we must do the fixup as early as possible
1954 // before the archived java objects are accessed by functions
1955 // such as java_lang_Class::restore_archived_mirror and
1956 // ConstantPool::restore_unshareable_info (restores the archived
1957 // resolved_references array object).
1958 //
1959 // HeapShared::fixup_mapped_heap_regions() fills the empty
1960 // spaces in the archived heap regions and may use
1961 // SystemDictionary::Object_klass(), so we can do this only after
1962 // Object_klass is resolved. See the above resolve_wk_klasses_through()
1963 // call. No mirror objects are accessed/restored in the above call.
1964 // Mirrors are restored after java.lang.Class is loaded.
1965 HeapShared::fixup_mapped_heap_regions();
1966
1967 // Initialize the constant pool for the Object_class
1968 assert(Object_klass()->is_shared(), "must be");
1969 Object_klass()->constants()->restore_unshareable_info(CHECK);
1970 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1971 } else
1972 #endif
1973 {
1974 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1975 }
1976
1977 // Calculate offsets for String and Class classes since they are loaded and
1978 // can be used after this point.
1979 java_lang_String::compute_offsets();
1980 java_lang_Class::compute_offsets();
1981
1982 // Fixup mirrors for classes loaded before java.lang.Class.
1983 // These calls iterate over the objects currently in the perm gen
1984 // so calling them at this point is matters (not before when there
1985 // are fewer objects and not later after there are more objects
1986 // in the perm gen.
1987 Universe::initialize_basic_type_mirrors(CHECK);
1988 Universe::fixup_mirrors(CHECK);
1989
1990 // do a bunch more:
1991 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1992
1993 // Preload ref klasses and set reference types
1994 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1995 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1996
1997 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
1998 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1999 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2000 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2001 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2002
2003 // JSR 292 classes
2004 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2005 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2006 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2007 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2008 WKID last = WKID_LIMIT;
2009 resolve_wk_klasses_until(last, scan, CHECK);
2010
2011 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2012 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2013 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2014 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2015 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2016 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2017 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2018 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2019 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2020 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2021
2022 { // Compute whether we should use checkPackageAccess or NOT
2023 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2024 _has_checkPackageAccess = (method != NULL);
2025 }
2026
2027 #ifdef ASSERT
2028 if (UseSharedSpaces) {
2029 assert(JvmtiExport::is_early_phase(),
2030 "All well known classes must be resolved in JVMTI early phase");
2031 for (int i = FIRST_WKID; i < last; i++) {
2032 InstanceKlass* k = _well_known_klasses[i];
2033 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2034 }
2035 }
2036 #endif
2037 }
2038
2039 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2040 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2041 BasicType SystemDictionary::box_klass_type(Klass* k) {
2042 assert(k != NULL, "");
2043 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2044 if (_box_klasses[i] == k)
2045 return (BasicType)i;
2046 }
2047 return T_OBJECT;
2048 }
2049
2050 // Constraints on class loaders. The details of the algorithm can be
2051 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2052 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2053 // that the dictionary needs to maintain a set of contraints that
2054 // must be satisfied by all classes in the dictionary.
2055 // if defining is true, then LinkageError if already in dictionary
2056 // if initiating loader, then ok if InstanceKlass matches existing entry
2057
2058 void SystemDictionary::check_constraints(unsigned int d_hash,
2059 InstanceKlass* k,
2060 Handle class_loader,
2061 bool defining,
2062 TRAPS) {
2063 ResourceMark rm(THREAD);
2064 stringStream ss;
2065 bool throwException = false;
2066
2067 {
2068 Symbol *name = k->name();
2069 ClassLoaderData *loader_data = class_loader_data(class_loader);
2070
2071 MutexLocker mu(SystemDictionary_lock, THREAD);
2072
2073 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2074 if (check != NULL) {
2075 // If different InstanceKlass - duplicate class definition,
2076 // else - ok, class loaded by a different thread in parallel.
2077 // We should only have found it if it was done loading and ok to use.
2078 // The dictionary only holds instance classes, placeholders
2079 // also hold array classes.
2080
2081 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2082 if ((defining == true) || (k != check)) {
2083 throwException = true;
2084 ss.print("loader %s", loader_data->loader_name_and_id());
2085 ss.print(" attempted duplicate %s definition for %s. (%s)",
2086 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2087 } else {
2088 return;
2089 }
2090 }
2091
2092 #ifdef ASSERT
2093 Symbol* ph_check = find_placeholder(name, loader_data);
2094 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2095 #endif
2096
2097 if (throwException == false) {
2098 if (constraints()->check_or_update(k, class_loader, name) == false) {
2099 throwException = true;
2100 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2101 ss.print(" wants to load %s %s.",
2102 k->external_kind(), k->external_name());
2103 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2104 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2105 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2106 existing_klass->external_kind(),
2107 existing_klass->class_loader_data()->loader_name_and_id(),
2108 existing_klass->class_in_module_of_loader(false, true));
2109 } else {
2110 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2111 }
2112 }
2113 }
2114 }
2115
2116 // Throw error now if needed (cannot throw while holding
2117 // SystemDictionary_lock because of rank ordering)
2118 if (throwException == true) {
2119 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2120 }
2121 }
2122
2123 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2124 // have been called.
2125 void SystemDictionary::update_dictionary(unsigned int d_hash,
2126 int p_index, unsigned int p_hash,
2127 InstanceKlass* k,
2128 Handle class_loader,
2129 TRAPS) {
2130 // Compile_lock prevents systemDictionary updates during compilations
2131 assert_locked_or_safepoint(Compile_lock);
2132 Symbol* name = k->name();
2133 ClassLoaderData *loader_data = class_loader_data(class_loader);
2134
2135 {
2136 MutexLocker mu1(SystemDictionary_lock, THREAD);
2137
2138 // See whether biased locking is enabled and if so set it for this
2139 // klass.
2140 // Note that this must be done past the last potential blocking
2141 // point / safepoint. We might enable biased locking lazily using a
2142 // VM_Operation to iterate the SystemDictionary and installing the
2143 // biasable mark word into each InstanceKlass's prototype header.
2144 // To avoid race conditions where we accidentally miss enabling the
2145 // optimization for one class in the process of being added to the
2146 // dictionary, we must not safepoint after the test of
2147 // BiasedLocking::enabled().
2148 if (UseBiasedLocking && BiasedLocking::enabled()) {
2149 // Set biased locking bit for all loaded classes; it will be
2150 // cleared if revocation occurs too often for this type
2151 // NOTE that we must only do this when the class is initally
2152 // defined, not each time it is referenced from a new class loader
2153 if (k->class_loader() == class_loader()) {
2154 k->set_prototype_header(markWord::biased_locking_prototype());
2155 }
2156 }
2157
2158 // Make a new dictionary entry.
2159 Dictionary* dictionary = loader_data->dictionary();
2160 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2161 if (sd_check == NULL) {
2162 dictionary->add_klass(d_hash, name, k);
2163 }
2164 #ifdef ASSERT
2165 sd_check = find_class(d_hash, name, dictionary);
2166 assert (sd_check != NULL, "should have entry in dictionary");
2167 // Note: there may be a placeholder entry: for circularity testing
2168 // or for parallel defines
2169 #endif
2170 SystemDictionary_lock->notify_all();
2171 }
2172 }
2173
2174
2175 // Try to find a class name using the loader constraints. The
2176 // loader constraints might know about a class that isn't fully loaded
2177 // yet and these will be ignored.
2178 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2179 Symbol* class_name, Handle class_loader, TRAPS) {
2180
2181 // First see if it has been loaded directly.
2182 // Force the protection domain to be null. (This removes protection checks.)
2183 Handle no_protection_domain;
2184 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2185 no_protection_domain, CHECK_NULL);
2186 if (klass != NULL)
2187 return klass;
2188
2189 // Now look to see if it has been loaded elsewhere, and is subject to
2190 // a loader constraint that would require this loader to return the
2191 // klass that is already loaded.
2192 if (FieldType::is_array(class_name)) {
2193 // For array classes, their Klass*s are not kept in the
2194 // constraint table. The element Klass*s are.
2195 FieldArrayInfo fd;
2196 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2197 if (t != T_OBJECT) {
2198 klass = Universe::typeArrayKlassObj(t);
2199 } else {
2200 MutexLocker mu(SystemDictionary_lock, THREAD);
2201 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2202 }
2203 // If element class already loaded, allocate array klass
2204 if (klass != NULL) {
2205 klass = klass->array_klass_or_null(fd.dimension());
2206 }
2207 } else {
2208 MutexLocker mu(SystemDictionary_lock, THREAD);
2209 // Non-array classes are easy: simply check the constraint table.
2210 klass = constraints()->find_constrained_klass(class_name, class_loader);
2211 }
2212
2213 return klass;
2214 }
2215
2216
2217 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2218 Handle class_loader1,
2219 Handle class_loader2,
2220 Thread* THREAD) {
2221 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2222 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2223
2224 Symbol* constraint_name = NULL;
2225 // Needs to be in same scope as constraint_name in case a Symbol is created and
2226 // assigned to constraint_name.
2227 FieldArrayInfo fd;
2228 if (!FieldType::is_array(class_name)) {
2229 constraint_name = class_name;
2230 } else {
2231 // For array classes, their Klass*s are not kept in the
2232 // constraint table. The element classes are.
2233 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2234 // primitive types always pass
2235 if (t != T_OBJECT) {
2236 return true;
2237 } else {
2238 constraint_name = fd.object_key();
2239 }
2240 }
2241
2242 Dictionary* dictionary1 = loader_data1->dictionary();
2243 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2244
2245 Dictionary* dictionary2 = loader_data2->dictionary();
2246 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2247
2248 {
2249 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2250 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2251 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2252 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2253 klass2, class_loader2);
2254 }
2255 }
2256
2257 // Add entry to resolution error table to record the error when the first
2258 // attempt to resolve a reference to a class has failed.
2259 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2260 Symbol* error, Symbol* message) {
2261 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2262 int index = resolution_errors()->hash_to_index(hash);
2263 {
2264 MutexLocker ml(SystemDictionary_lock, Thread::current());
2265 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2266 }
2267 }
2268
2269 // Delete a resolution error for RedefineClasses for a constant pool is going away
2270 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2271 resolution_errors()->delete_entry(pool);
2272 }
2273
2274 // Lookup resolution error table. Returns error if found, otherwise NULL.
2275 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2276 Symbol** message) {
2277 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2278 int index = resolution_errors()->hash_to_index(hash);
2279 {
2280 MutexLocker ml(SystemDictionary_lock, Thread::current());
2281 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2282 if (entry != NULL) {
2283 *message = entry->message();
2284 return entry->error();
2285 } else {
2286 return NULL;
2287 }
2288 }
2289 }
2290
2291
2292 // Signature constraints ensure that callers and callees agree about
2293 // the meaning of type names in their signatures. This routine is the
2294 // intake for constraints. It collects them from several places:
2295 //
2296 // * LinkResolver::resolve_method (if check_access is true) requires
2297 // that the resolving class (the caller) and the defining class of
2298 // the resolved method (the callee) agree on each type in the
2299 // method's signature.
2300 //
2301 // * LinkResolver::resolve_interface_method performs exactly the same
2302 // checks.
2303 //
2304 // * LinkResolver::resolve_field requires that the constant pool
2305 // attempting to link to a field agree with the field's defining
2306 // class about the type of the field signature.
2307 //
2308 // * klassVtable::initialize_vtable requires that, when a class
2309 // overrides a vtable entry allocated by a superclass, that the
2310 // overriding method (i.e., the callee) agree with the superclass
2311 // on each type in the method's signature.
2312 //
2313 // * klassItable::initialize_itable requires that, when a class fills
2314 // in its itables, for each non-abstract method installed in an
2315 // itable, the method (i.e., the callee) agree with the interface
2316 // on each type in the method's signature.
2317 //
2318 // All those methods have a boolean (check_access, checkconstraints)
2319 // which turns off the checks. This is used from specialized contexts
2320 // such as bootstrapping, dumping, and debugging.
2321 //
2322 // No direct constraint is placed between the class and its
2323 // supertypes. Constraints are only placed along linked relations
2324 // between callers and callees. When a method overrides or implements
2325 // an abstract method in a supertype (superclass or interface), the
2326 // constraints are placed as if the supertype were the caller to the
2327 // overriding method. (This works well, since callers to the
2328 // supertype have already established agreement between themselves and
2329 // the supertype.) As a result of all this, a class can disagree with
2330 // its supertype about the meaning of a type name, as long as that
2331 // class neither calls a relevant method of the supertype, nor is
2332 // called (perhaps via an override) from the supertype.
2333 //
2334 //
2335 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2336 //
2337 // Make sure all class components (including arrays) in the given
2338 // signature will be resolved to the same class in both loaders.
2339 // Returns the name of the type that failed a loader constraint check, or
2340 // NULL if no constraint failed. No exception except OOME is thrown.
2341 // Arrays are not added to the loader constraint table, their elements are.
2342 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2343 Handle loader1, Handle loader2,
2344 bool is_method, TRAPS) {
2345 // Nothing to do if loaders are the same.
2346 if (loader1() == loader2()) {
2347 return NULL;
2348 }
2349
2350 SignatureStream sig_strm(signature, is_method);
2351 while (!sig_strm.is_done()) {
2352 if (sig_strm.is_object()) {
2353 Symbol* sig = sig_strm.as_symbol();
2354 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2355 return sig;
2356 }
2357 }
2358 sig_strm.next();
2359 }
2360 return NULL;
2361 }
2362
2363
2364 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2365 Symbol* signature,
2366 TRAPS) {
2367 methodHandle empty;
2368 assert(MethodHandles::is_signature_polymorphic(iid) &&
2369 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2370 iid != vmIntrinsics::_invokeGeneric,
2371 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2372
2373 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2374 int index = invoke_method_table()->hash_to_index(hash);
2375 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2376 methodHandle m;
2377 if (spe == NULL || spe->method() == NULL) {
2378 spe = NULL;
2379 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2380 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2381 if (!Arguments::is_interpreter_only()) {
2382 // Generate a compiled form of the MH intrinsic.
2383 AdapterHandlerLibrary::create_native_wrapper(m);
2384 // Check if have the compiled code.
2385 if (!m->has_compiled_code()) {
2386 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2387 "Out of space in CodeCache for method handle intrinsic", empty);
2388 }
2389 }
2390 // Now grab the lock. We might have to throw away the new method,
2391 // if a racing thread has managed to install one at the same time.
2392 {
2393 MutexLocker ml(SystemDictionary_lock, THREAD);
2394 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2395 if (spe == NULL)
2396 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2397 if (spe->method() == NULL)
2398 spe->set_method(m());
2399 }
2400 }
2401
2402 assert(spe != NULL && spe->method() != NULL, "");
2403 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2404 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2405 "MH intrinsic invariant");
2406 return spe->method();
2407 }
2408
2409 // Helper for unpacking the return value from linkMethod and linkCallSite.
2410 static methodHandle unpack_method_and_appendix(Handle mname,
2411 Klass* accessing_klass,
2412 objArrayHandle appendix_box,
2413 Handle* appendix_result,
2414 TRAPS) {
2415 methodHandle empty;
2416 if (mname.not_null()) {
2417 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2418 if (m != NULL) {
2419 oop appendix = appendix_box->obj_at(0);
2420 if (TraceMethodHandles) {
2421 #ifndef PRODUCT
2422 ttyLocker ttyl;
2423 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2424 m->print();
2425 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2426 tty->cr();
2427 #endif //PRODUCT
2428 }
2429 (*appendix_result) = Handle(THREAD, appendix);
2430 // the target is stored in the cpCache and if a reference to this
2431 // MemberName is dropped we need a way to make sure the
2432 // class_loader containing this method is kept alive.
2433 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2434 this_key->record_dependency(m->method_holder());
2435 return methodHandle(THREAD, m);
2436 }
2437 }
2438 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2439 return empty;
2440 }
2441
2442 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2443 Symbol* name,
2444 Symbol* signature,
2445 Klass* accessing_klass,
2446 Handle *appendix_result,
2447 TRAPS) {
2448 methodHandle empty;
2449 assert(THREAD->can_call_java() ,"");
2450 Handle method_type =
2451 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2452
2453 int ref_kind = JVM_REF_invokeVirtual;
2454 oop name_oop = StringTable::intern(name, CHECK_(empty));
2455 Handle name_str (THREAD, name_oop);
2456 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2457 assert(appendix_box->obj_at(0) == NULL, "");
2458
2459 // This should not happen. JDK code should take care of that.
2460 if (accessing_klass == NULL || method_type.is_null()) {
2461 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2462 }
2463
2464 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2465 JavaCallArguments args;
2466 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2467 args.push_int(ref_kind);
2468 args.push_oop(Handle(THREAD, klass->java_mirror()));
2469 args.push_oop(name_str);
2470 args.push_oop(method_type);
2471 args.push_oop(appendix_box);
2472 JavaValue result(T_OBJECT);
2473 JavaCalls::call_static(&result,
2474 SystemDictionary::MethodHandleNatives_klass(),
2475 vmSymbols::linkMethod_name(),
2476 vmSymbols::linkMethod_signature(),
2477 &args, CHECK_(empty));
2478 Handle mname(THREAD, (oop) result.get_jobject());
2479 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2480 }
2481
2482 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2483 // We must ensure that all class loaders everywhere will reach this class, for any client.
2484 // This is a safe bet for public classes in java.lang, such as Object and String.
2485 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2486 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2487 static bool is_always_visible_class(oop mirror) {
2488 Klass* klass = java_lang_Class::as_Klass(mirror);
2489 if (klass->is_objArray_klass()) {
2490 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2491 }
2492 if (klass->is_typeArray_klass()) {
2493 return true; // primitive array
2494 }
2495 assert(klass->is_instance_klass(), "%s", klass->external_name());
2496 return klass->is_public() &&
2497 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2498 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2499 }
2500
2501
2502 // Return the Java mirror (java.lang.Class instance) for a single-character
2503 // descriptor. This result, when available, is the same as produced by the
2504 // heavier API point of the same name that takes a Symbol.
2505 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2506 return java_lang_Class::primitive_mirror(char2type(signature_char));
2507 }
2508
2509 // Find or construct the Java mirror (java.lang.Class instance) for a
2510 // for the given field type signature, as interpreted relative to the
2511 // given class loader. Handles primitives, void, references, arrays,
2512 // and all other reflectable types, except method types.
2513 // N.B. Code in reflection should use this entry point.
2514 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2515 Klass* accessing_klass,
2516 Handle class_loader,
2517 Handle protection_domain,
2518 SignatureStream::FailureMode failure_mode,
2519 TRAPS) {
2520 Handle empty;
2521
2522 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2523 "one or the other, or perhaps neither");
2524
2525 Symbol* type = signature;
2526
2527 // What we have here must be a valid field descriptor,
2528 // and all valid field descriptors are supported.
2529 // Produce the same java.lang.Class that reflection reports.
2530 if (type->utf8_length() == 1) {
2531
2532 // It's a primitive. (Void has a primitive mirror too.)
2533 char ch = type->char_at(0);
2534 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2535 return Handle(THREAD, find_java_mirror_for_type(ch));
2536
2537 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2538
2539 // It's a reference type.
2540 if (accessing_klass != NULL) {
2541 class_loader = Handle(THREAD, accessing_klass->class_loader());
2542 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2543 }
2544 Klass* constant_type_klass;
2545 if (failure_mode == SignatureStream::ReturnNull) {
2546 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2547 CHECK_(empty));
2548 } else {
2549 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2550 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2551 throw_error, CHECK_(empty));
2552 }
2553 if (constant_type_klass == NULL) {
2554 return Handle(); // report failure this way
2555 }
2556 Handle mirror(THREAD, constant_type_klass->java_mirror());
2557
2558 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2559 if (accessing_klass != NULL) {
2560 Klass* sel_klass = constant_type_klass;
2561 bool fold_type_to_class = true;
2562 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2563 fold_type_to_class, CHECK_(empty));
2564 }
2565
2566 return mirror;
2567
2568 }
2569
2570 // Fall through to an error.
2571 assert(false, "unsupported mirror syntax");
2572 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2573 }
2574
2575
2576 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2577 // signature, as interpreted relative to the given class loader.
2578 // Because of class loader constraints, all method handle usage must be
2579 // consistent with this loader.
2580 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2581 Klass* accessing_klass,
2582 TRAPS) {
2583 Handle empty;
2584 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2585 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2586 int index = invoke_method_table()->hash_to_index(hash);
2587 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2588 if (spe != NULL && spe->method_type() != NULL) {
2589 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2590 return Handle(THREAD, spe->method_type());
2591 } else if (!THREAD->can_call_java()) {
2592 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2593 return Handle(); // do not attempt from within compiler, unless it was cached
2594 }
2595
2596 Handle class_loader, protection_domain;
2597 if (accessing_klass != NULL) {
2598 class_loader = Handle(THREAD, accessing_klass->class_loader());
2599 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2600 }
2601 bool can_be_cached = true;
2602 int npts = ArgumentCount(signature).size();
2603 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2604 int arg = 0;
2605 Handle rt; // the return type from the signature
2606 ResourceMark rm(THREAD);
2607 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2608 oop mirror = NULL;
2609 if (can_be_cached) {
2610 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2611 mirror = ss.as_java_mirror(Handle(), Handle(),
2612 SignatureStream::ReturnNull, CHECK_(empty));
2613 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2614 // Fall back to accessing_klass context.
2615 can_be_cached = false;
2616 }
2617 }
2618 if (!can_be_cached) {
2619 // Resolve, throwing a real error if it doesn't work.
2620 mirror = ss.as_java_mirror(class_loader, protection_domain,
2621 SignatureStream::NCDFError, CHECK_(empty));
2622 }
2623 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2624 if (ss.at_return_type())
2625 rt = Handle(THREAD, mirror);
2626 else
2627 pts->obj_at_put(arg++, mirror);
2628
2629 // Check accessibility.
2630 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2631 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2632 mirror = NULL; // safety
2633 // Emulate ConstantPool::verify_constant_pool_resolve.
2634 bool fold_type_to_class = true;
2635 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2636 fold_type_to_class, CHECK_(empty));
2637 }
2638 }
2639 assert(arg == npts, "");
2640
2641 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2642 JavaCallArguments args(Handle(THREAD, rt()));
2643 args.push_oop(pts);
2644 JavaValue result(T_OBJECT);
2645 JavaCalls::call_static(&result,
2646 SystemDictionary::MethodHandleNatives_klass(),
2647 vmSymbols::findMethodHandleType_name(),
2648 vmSymbols::findMethodHandleType_signature(),
2649 &args, CHECK_(empty));
2650 Handle method_type(THREAD, (oop) result.get_jobject());
2651
2652 if (can_be_cached) {
2653 // We can cache this MethodType inside the JVM.
2654 MutexLocker ml(SystemDictionary_lock, THREAD);
2655 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2656 if (spe == NULL)
2657 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2658 if (spe->method_type() == NULL) {
2659 spe->set_method_type(method_type());
2660 }
2661 }
2662
2663 // report back to the caller with the MethodType
2664 return method_type;
2665 }
2666
2667 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2668 Klass* accessing_klass,
2669 TRAPS) {
2670 Handle empty;
2671 ResourceMark rm(THREAD);
2672 SignatureStream ss(signature, /*is_method=*/ false);
2673 if (!ss.is_done()) {
2674 Handle class_loader, protection_domain;
2675 if (accessing_klass != NULL) {
2676 class_loader = Handle(THREAD, accessing_klass->class_loader());
2677 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2678 }
2679 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2680 ss.next();
2681 if (ss.is_done()) {
2682 return Handle(THREAD, mirror);
2683 }
2684 }
2685 return empty;
2686 }
2687
2688 // Ask Java code to find or construct a method handle constant.
2689 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2690 int ref_kind, //e.g., JVM_REF_invokeVirtual
2691 Klass* callee,
2692 Symbol* name,
2693 Symbol* signature,
2694 TRAPS) {
2695 Handle empty;
2696 if (caller == NULL) {
2697 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2698 }
2699 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2700 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2701
2702 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2703 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2704 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2705 java_lang_invoke_MemberName::set_name (mname(), name_str());
2706 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2707 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2708
2709 if (ref_kind == JVM_REF_invokeVirtual &&
2710 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2711 // Skip resolution for public signature polymorphic methods such as
2712 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2713 // They require appendix argument which MemberName resolution doesn't handle.
2714 // There's special logic on JDK side to handle them
2715 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2716 } else {
2717 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2718 }
2719
2720 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2721 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2722
2723 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2724 JavaCallArguments args;
2725 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2726 args.push_int(ref_kind);
2727 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2728 args.push_oop(name_str);
2729 args.push_oop(type);
2730 JavaValue result(T_OBJECT);
2731 JavaCalls::call_static(&result,
2732 SystemDictionary::MethodHandleNatives_klass(),
2733 vmSymbols::linkMethodHandleConstant_name(),
2734 vmSymbols::linkMethodHandleConstant_signature(),
2735 &args, CHECK_(empty));
2736 return Handle(THREAD, (oop) result.get_jobject());
2737 }
2738
2739 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2740 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2741 // with linkage results being stored back into the bootstrap specifier.
2742 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2743 // Resolve the bootstrap specifier, its name, type, and static arguments
2744 bootstrap_specifier.resolve_bsm(CHECK);
2745
2746 // This should not happen. JDK code should take care of that.
2747 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2748 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2749 }
2750
2751 bool is_indy = bootstrap_specifier.is_method_call();
2752 objArrayHandle appendix_box;
2753 if (is_indy) {
2754 // Some method calls may require an appendix argument. Arrange to receive it.
2755 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2756 assert(appendix_box->obj_at(0) == NULL, "");
2757 }
2758
2759 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2760 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2761 JavaCallArguments args;
2762 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2763 args.push_int(bootstrap_specifier.bss_index());
2764 args.push_oop(bootstrap_specifier.bsm());
2765 args.push_oop(bootstrap_specifier.name_arg());
2766 args.push_oop(bootstrap_specifier.type_arg());
2767 args.push_oop(bootstrap_specifier.arg_values());
2768 if (is_indy) {
2769 args.push_oop(appendix_box);
2770 }
2771 JavaValue result(T_OBJECT);
2772 JavaCalls::call_static(&result,
2773 SystemDictionary::MethodHandleNatives_klass(),
2774 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2775 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2776 &args, CHECK);
2777
2778 Handle value(THREAD, (oop) result.get_jobject());
2779 if (is_indy) {
2780 Handle appendix;
2781 methodHandle method = unpack_method_and_appendix(value,
2782 bootstrap_specifier.caller(),
2783 appendix_box,
2784 &appendix, CHECK);
2785 bootstrap_specifier.set_resolved_method(method, appendix);
2786 } else {
2787 bootstrap_specifier.set_resolved_value(value);
2788 }
2789
2790 // sanity check
2791 assert(bootstrap_specifier.is_resolved() ||
2792 (bootstrap_specifier.is_method_call() &&
2793 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2794 }
2795
2796 // Protection domain cache table handling
2797
2798 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2799 return _pd_cache_table->get(protection_domain);
2800 }
2801
2802 // ----------------------------------------------------------------------------
2803
2804 void SystemDictionary::print_on(outputStream *st) {
2805 CDS_ONLY(SystemDictionaryShared::print_on(st));
2806 GCMutexLocker mu(SystemDictionary_lock);
2807
2808 ClassLoaderDataGraph::print_dictionary(st);
2809
2810 // Placeholders
2811 placeholders()->print_on(st);
2812 st->cr();
2813
2814 // loader constraints - print under SD_lock
2815 constraints()->print_on(st);
2816 st->cr();
2817
2818 _pd_cache_table->print_on(st);
2819 st->cr();
2820 }
2821
2822 void SystemDictionary::print() { print_on(tty); }
2823
2824 void SystemDictionary::verify() {
2825 guarantee(constraints() != NULL,
2826 "Verify of loader constraints failed");
2827 guarantee(placeholders()->number_of_entries() >= 0,
2828 "Verify of placeholders failed");
2829
2830 GCMutexLocker mu(SystemDictionary_lock);
2831
2832 // Verify dictionary
2833 ClassLoaderDataGraph::verify_dictionary();
2834
2835 placeholders()->verify();
2836
2837 // Verify constraint table
2838 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2839 constraints()->verify(placeholders());
2840
2841 _pd_cache_table->verify();
2842 }
2843
2844 void SystemDictionary::dump(outputStream *st, bool verbose) {
2845 assert_locked_or_safepoint(SystemDictionary_lock);
2846 if (verbose) {
2847 print_on(st);
2848 } else {
2849 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2850 ClassLoaderDataGraph::print_table_statistics(st);
2851 placeholders()->print_table_statistics(st, "Placeholder Table");
2852 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2853 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2854 }
2855 }
2856
2857 TableStatistics SystemDictionary::placeholders_statistics() {
2858 MutexLocker ml(SystemDictionary_lock);
2859 return placeholders()->statistics_calculate();
2860 }
2861
2862 TableStatistics SystemDictionary::loader_constraints_statistics() {
2863 MutexLocker ml(SystemDictionary_lock);
2864 return constraints()->statistics_calculate();
2865 }
2866
2867 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2868 MutexLocker ml(SystemDictionary_lock);
2869 return pd_cache_table()->statistics_calculate();
2870 }
2871
2872 // Utility for dumping dictionaries.
2873 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2874 DCmdWithParser(output, heap),
2875 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2876 "BOOLEAN", false, "false") {
2877 _dcmdparser.add_dcmd_option(&_verbose);
2878 }
2879
2880 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2881 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2882 _verbose.value());
2883 VMThread::execute(&dumper);
2884 }
2885
2886 int SystemDictionaryDCmd::num_arguments() {
2887 ResourceMark rm;
2888 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2889 if (dcmd != NULL) {
2890 DCmdMark mark(dcmd);
2891 return dcmd->_dcmdparser.num_arguments();
2892 } else {
2893 return 0;
2894 }
2895 }