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/sharedRuntime.hpp"
83 #include "runtime/signature.hpp"
84 #include "services/classLoadingService.hpp"
85 #include "services/diagnosticCommand.hpp"
86 #include "services/threadService.hpp"
87 #include "utilities/macros.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JFR
92 #include "jfr/jfr.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 // Default ProtectionDomainCacheSize value
112
113 const int defaultProtectionDomainCacheSize = 1009;
114
115 // ----------------------------------------------------------------------------
116 // Java-level SystemLoader and PlatformLoader
117
118 oop SystemDictionary::java_system_loader() {
119 return _java_system_loader;
120 }
121
122 oop SystemDictionary::java_platform_loader() {
123 return _java_platform_loader;
124 }
125
126 void SystemDictionary::compute_java_loaders(TRAPS) {
127 JavaValue result(T_OBJECT);
128 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
129 JavaCalls::call_static(&result,
130 class_loader_klass,
131 vmSymbols::getSystemClassLoader_name(),
132 vmSymbols::void_classloader_signature(),
133 CHECK);
134
135 _java_system_loader = (oop)result.get_jobject();
136
137 JavaCalls::call_static(&result,
138 class_loader_klass,
139 vmSymbols::getPlatformClassLoader_name(),
140 vmSymbols::void_classloader_signature(),
141 CHECK);
142
143 _java_platform_loader = (oop)result.get_jobject();
144 }
145
146 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
147 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
148 return ClassLoaderDataGraph::find_or_create(class_loader);
149 }
150
151 // ----------------------------------------------------------------------------
152 // Parallel class loading check
153
154 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
155 if (class_loader.is_null()) return true;
156 if (AlwaysLockClassLoader) return false;
157 return java_lang_ClassLoader::parallelCapable(class_loader());
158 }
159 // ----------------------------------------------------------------------------
160 // ParallelDefineClass flag does not apply to bootclass loader
161 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
162 if (class_loader.is_null()) return false;
163 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
164 return true;
165 }
166 return false;
167 }
168
169 // Returns true if the passed class loader is the builtin application class loader
170 // or a custom system class loader. A customer system class loader can be
171 // specified via -Djava.system.class.loader.
172 bool SystemDictionary::is_system_class_loader(oop class_loader) {
173 if (class_loader == NULL) {
174 return false;
175 }
176 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
177 class_loader == _java_system_loader);
178 }
179
180 // Returns true if the passed class loader is the platform class loader.
181 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
182 if (class_loader == NULL) {
183 return false;
184 }
185 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
186 }
187
188 // ----------------------------------------------------------------------------
189 // Resolving of classes
190
191 // Forwards to resolve_or_null
192
193 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
194 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
195 if (HAS_PENDING_EXCEPTION || klass == NULL) {
196 // can return a null klass
197 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
198 }
199 return klass;
200 }
201
202 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
203 bool throw_error,
204 Klass* klass, TRAPS) {
205 if (HAS_PENDING_EXCEPTION) {
206 // If we have a pending exception we forward it to the caller, unless throw_error is true,
207 // in which case we have to check whether the pending exception is a ClassNotFoundException,
208 // and if so convert it to a NoClassDefFoundError
209 // And chain the original ClassNotFoundException
210 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
211 ResourceMark rm(THREAD);
212 assert(klass == NULL, "Should not have result with exception pending");
213 Handle e(THREAD, PENDING_EXCEPTION);
214 CLEAR_PENDING_EXCEPTION;
215 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
216 } else {
217 return NULL;
218 }
219 }
220 // Class not found, throw appropriate error or exception depending on value of throw_error
221 if (klass == NULL) {
222 ResourceMark rm(THREAD);
223 if (throw_error) {
224 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
225 } else {
226 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
227 }
228 }
229 return klass;
230 }
231
232
233 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
234 bool throw_error, TRAPS)
235 {
236 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
237 }
238
239
240 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
241
242 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
243 if (FieldType::is_array(class_name)) {
244 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
245 } else {
246 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
247 }
248 }
249
250 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
251 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
252 Handle class_loader,
253 Handle protection_domain,
254 TRAPS) {
255 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
256 if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* super_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 assert(!FieldType::is_array(super_name), "invalid super class name");
346 #if INCLUDE_CDS
347 if (DumpSharedSpaces) {
348 // Special processing for handling UNREGISTERED shared classes.
349 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
350 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
351 if (k) {
352 return k;
353 }
354 }
355 #endif // INCLUDE_CDS
356
357 // Double-check, if child class is already loaded, just return super-class,interface
358 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
359 // dictionary.
360 // Make sure there's a placeholder for the *child* before resolving.
361 // Used as a claim that this thread is currently loading superclass/classloader
362 // Used here for ClassCircularity checks and also for heap verification
363 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
364 // Must check ClassCircularity before checking if super class is already loaded.
365 //
366 // We might not already have a placeholder if this child_name was
367 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
368 // the name of the class might not be known until the stream is actually
369 // parsed.
370 // Bugs 4643874, 4715493
371
372 ClassLoaderData* loader_data = class_loader_data(class_loader);
373 Dictionary* dictionary = loader_data->dictionary();
374 unsigned int d_hash = dictionary->compute_hash(child_name);
375 unsigned int p_hash = placeholders()->compute_hash(child_name);
376 int p_index = placeholders()->hash_to_index(p_hash);
377 // can't throw error holding a lock
378 bool child_already_loaded = false;
379 bool throw_circularity_error = false;
380 {
381 MutexLocker mu(SystemDictionary_lock, THREAD);
382 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
383 InstanceKlass* quicksuperk;
384 // to support // loading: if child done loading, just return superclass
385 // if super_name, & class_loader don't match:
386 // if initial define, SD update will give LinkageError
387 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
388 // so we don't throw an exception here.
389 // see: nsk redefclass014 & java.lang.instrument Instrument032
390 if ((childk != NULL ) && (is_superclass) &&
391 ((quicksuperk = childk->java_super()) != NULL) &&
392 ((quicksuperk->name() == super_name) &&
393 (quicksuperk->class_loader() == class_loader()))) {
394 return quicksuperk;
395 } else {
396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
398 throw_circularity_error = true;
399 }
400 }
401 if (!throw_circularity_error) {
402 // Be careful not to exit resolve_super
403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
404 }
405 }
406 if (throw_circularity_error) {
407 ResourceMark rm(THREAD);
408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
409 }
410
411 // java.lang.Object should have been found above
412 assert(super_name != NULL, "null super class for resolving");
413 // Resolve the super class or interface, check results on return
414 InstanceKlass* superk =
415 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
416 class_loader,
417 protection_domain,
418 THREAD);
419
420 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
421 // It is no longer necessary to keep the placeholder table alive until update_dictionary
422 // or error. GC used to walk the placeholder table as strong roots.
423 // The instanceKlass is kept alive because the class loader is on the stack,
424 // which keeps the loader_data alive, as well as all instanceKlasses in
425 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
426 {
427 MutexLocker mu(SystemDictionary_lock, THREAD);
428 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
429 SystemDictionary_lock->notify_all();
430 }
431 if (HAS_PENDING_EXCEPTION || superk == NULL) {
432 // can null superk
433 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
434 assert(k == NULL || k == superk, "must be");
435 if (k == NULL) {
436 superk = NULL;
437 }
438 }
439
440 return superk;
441 }
442
443 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
444 Handle class_loader,
445 Handle protection_domain,
446 TRAPS) {
447 // Now we have to call back to java to check if the initating class has access
448 JavaValue result(T_VOID);
449 LogTarget(Debug, protectiondomain) lt;
450 if (lt.is_enabled()) {
451 ResourceMark rm(THREAD);
452 // Print out trace information
453 LogStream ls(lt);
454 ls.print_cr("Checking package access");
455 if (class_loader() != NULL) {
456 ls.print("class loader: ");
457 class_loader()->print_value_on(&ls);
458 } else {
459 ls.print_cr("class loader: NULL");
460 }
461 if (protection_domain() != NULL) {
462 ls.print(" protection domain: ");
463 protection_domain()->print_value_on(&ls);
464 } else {
465 ls.print_cr(" protection domain: NULL");
466 }
467 ls.print(" loading: "); klass->print_value_on(&ls);
468 ls.cr();
469 }
470
471 // This handle and the class_loader handle passed in keeps this class from
472 // being unloaded through several GC points.
473 // The class_loader handle passed in is the initiating loader.
474 Handle mirror(THREAD, klass->java_mirror());
475
476 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
477 JavaCalls::call_special(&result,
478 class_loader,
479 system_loader,
480 vmSymbols::checkPackageAccess_name(),
481 vmSymbols::class_protectiondomain_signature(),
482 mirror,
483 protection_domain,
484 THREAD);
485
486 if (HAS_PENDING_EXCEPTION) {
487 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
488 } else {
489 log_debug(protectiondomain)("granted");
490 }
491
492 if (HAS_PENDING_EXCEPTION) return;
493
494 // If no exception has been thrown, we have validated the protection domain
495 // Insert the protection domain of the initiating class into the set.
496 {
497 ClassLoaderData* loader_data = class_loader_data(class_loader);
498 Dictionary* dictionary = loader_data->dictionary();
499
500 Symbol* kn = klass->name();
501 unsigned int d_hash = dictionary->compute_hash(kn);
502
503 MutexLocker mu(SystemDictionary_lock, THREAD);
504 int d_index = dictionary->hash_to_index(d_hash);
505 dictionary->add_protection_domain(d_index, d_hash, klass,
506 protection_domain, THREAD);
507 }
508 }
509
510 // We only get here if this thread finds that another thread
511 // has already claimed the placeholder token for the current operation,
512 // but that other thread either never owned or gave up the
513 // object lock
514 // Waits on SystemDictionary_lock to indicate placeholder table updated
515 // On return, caller must recheck placeholder table state
516 //
517 // We only get here if
518 // 1) custom classLoader, i.e. not bootstrap classloader
519 // 2) custom classLoader has broken the class loader objectLock
520 // so another thread got here in parallel
521 //
522 // lockObject must be held.
523 // Complicated dance due to lock ordering:
524 // Must first release the classloader object lock to
525 // allow initial definer to complete the class definition
526 // and to avoid deadlock
527 // Reclaim classloader lock object with same original recursion count
528 // Must release SystemDictionary_lock after notify, since
529 // class loader lock must be claimed before SystemDictionary_lock
530 // to prevent deadlocks
531 //
532 // The notify allows applications that did an untimed wait() on
533 // the classloader object lock to not hang.
534 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
535 assert_lock_strong(SystemDictionary_lock);
536
537 bool calledholdinglock
538 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
539 assert(calledholdinglock,"must hold lock for notify");
540 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
541 ObjectSynchronizer::notifyall(lockObject, THREAD);
542 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
543 SystemDictionary_lock->wait();
544 SystemDictionary_lock->unlock();
545 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
546 SystemDictionary_lock->lock();
547 }
548
549 // If the class in is in the placeholder table, class loading is in progress
550 // For cases where the application changes threads to load classes, it
551 // is critical to ClassCircularity detection that we try loading
552 // the superclass on the same thread internally, so we do parallel
553 // super class loading here.
554 // This also is critical in cases where the original thread gets stalled
555 // even in non-circularity situations.
556 // Note: must call resolve_super_or_fail even if null super -
557 // to force placeholder entry creation for this class for circularity detection
558 // Caller must check for pending exception
559 // Returns non-null Klass* if other thread has completed load
560 // and we are done,
561 // If return null Klass* and no pending exception, the caller must load the class
562 InstanceKlass* SystemDictionary::handle_parallel_super_load(
563 Symbol* name, Symbol* superclassname, Handle class_loader,
564 Handle protection_domain, Handle lockObject, TRAPS) {
565
566 ClassLoaderData* loader_data = class_loader_data(class_loader);
567 Dictionary* dictionary = loader_data->dictionary();
568 unsigned int d_hash = dictionary->compute_hash(name);
569 unsigned int p_hash = placeholders()->compute_hash(name);
570 int p_index = placeholders()->hash_to_index(p_hash);
571
572 // superk is not used, resolve_super called for circularity check only
573 // This code is reached in two situations. One if this thread
574 // is loading the same class twice (e.g. ClassCircularity, or
575 // java.lang.instrument).
576 // The second is if another thread started the resolve_super first
577 // and has not yet finished.
578 // In both cases the original caller will clean up the placeholder
579 // entry on error.
580 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
581 superclassname,
582 class_loader,
583 protection_domain,
584 true,
585 CHECK_NULL);
586
587 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
588 // Serial class loaders and bootstrap classloader do wait for superclass loads
589 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
590 MutexLocker mu(SystemDictionary_lock, THREAD);
591 // Check if classloading completed while we were loading superclass or waiting
592 return find_class(d_hash, name, dictionary);
593 }
594
595 // must loop to both handle other placeholder updates
596 // and spurious notifications
597 bool super_load_in_progress = true;
598 PlaceholderEntry* placeholder;
599 while (super_load_in_progress) {
600 MutexLocker mu(SystemDictionary_lock, THREAD);
601 // Check if classloading completed while we were loading superclass or waiting
602 InstanceKlass* check = find_class(d_hash, name, dictionary);
603 if (check != NULL) {
604 // Klass is already loaded, so just return it
605 return check;
606 } else {
607 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
608 if (placeholder && placeholder->super_load_in_progress() ){
609 // We only get here if the application has released the
610 // classloader lock when another thread was in the middle of loading a
611 // superclass/superinterface for this class, and now
612 // this thread is also trying to load this class.
613 // To minimize surprises, the first thread that started to
614 // load a class should be the one to complete the loading
615 // with the classfile it initially expected.
616 // This logic has the current thread wait once it has done
617 // all the superclass/superinterface loading it can, until
618 // the original thread completes the class loading or fails
619 // If it completes we will use the resulting InstanceKlass
620 // which we will find below in the systemDictionary.
621 // We also get here for parallel bootstrap classloader
622 if (class_loader.is_null()) {
623 SystemDictionary_lock->wait();
624 } else {
625 double_lock_wait(lockObject, THREAD);
626 }
627 } else {
628 // If not in SD and not in PH, other thread's load must have failed
629 super_load_in_progress = false;
630 }
631 }
632 }
633 return NULL;
634 }
635
636 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
637 assert(event != NULL, "invariant");
638 assert(k != NULL, "invariant");
639 assert(event->should_commit(), "invariant");
640 event->set_loadedClass(k);
641 event->set_definingClassLoader(k->class_loader_data());
642 event->set_initiatingClassLoader(init_cld);
643 event->commit();
644 }
645
646
647 // Be careful when modifying this code: once you have run
648 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
649 // you need to find_and_remove it before returning.
650 // So be careful to not exit with a CHECK_ macro betweeen these calls.
651 //
652 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
653 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
654 Handle class_loader,
655 Handle protection_domain,
656 TRAPS) {
657 assert(name != NULL && !FieldType::is_array(name) &&
658 !FieldType::is_obj(name), "invalid class name");
659
660 EventClassLoad class_load_start_event;
661
662 HandleMark hm(THREAD);
663
664 // Fix for 4474172; see evaluation for more details
665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
666 ClassLoaderData* loader_data = register_loader(class_loader);
667 Dictionary* dictionary = loader_data->dictionary();
668 unsigned int d_hash = dictionary->compute_hash(name);
669
670 // Do lookup to see if class already exist and the protection domain
671 // has the right access
672 // This call uses find which checks protection domain already matches
673 // All subsequent calls use find_class, and set has_loaded_class so that
674 // before we return a result we call out to java to check for valid protection domain
675 // to allow returning the Klass* and add it to the pd_set if it is valid
676 {
677 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
678 if (probe != NULL) return probe;
679 }
680
681 // Non-bootstrap class loaders will call out to class loader and
682 // define via jvm/jni_DefineClass which will acquire the
683 // class loader object lock to protect against multiple threads
684 // defining the class in parallel by accident.
685 // This lock must be acquired here so the waiter will find
686 // any successful result in the SystemDictionary and not attempt
687 // the define.
688 // ParallelCapable Classloaders and the bootstrap classloader
689 // do not acquire lock here.
690 bool DoObjectLock = true;
691 if (is_parallelCapable(class_loader)) {
692 DoObjectLock = false;
693 }
694
695 unsigned int p_hash = placeholders()->compute_hash(name);
696 int p_index = placeholders()->hash_to_index(p_hash);
697
698 // Class is not in SystemDictionary so we have to do loading.
699 // Make sure we are synchronized on the class loader before we proceed
700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
701 check_loader_lock_contention(lockObject, THREAD);
702 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
703
704 // Check again (after locking) if class already exist in SystemDictionary
705 bool class_has_been_loaded = false;
706 bool super_load_in_progress = false;
707 bool havesupername = false;
708 InstanceKlass* k = NULL;
709 PlaceholderEntry* placeholder;
710 Symbol* superclassname = NULL;
711
712 assert(THREAD->can_call_java(),
713 "can not load classes with compiler thread: class=%s, classloader=%s",
714 name->as_C_string(),
715 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
716 {
717 MutexLocker mu(SystemDictionary_lock, THREAD);
718 InstanceKlass* check = find_class(d_hash, name, dictionary);
719 if (check != NULL) {
720 // InstanceKlass is already loaded, so just return it
721 class_has_been_loaded = true;
722 k = check;
723 } else {
724 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
725 if (placeholder && placeholder->super_load_in_progress()) {
726 super_load_in_progress = true;
727 if (placeholder->havesupername() == true) {
728 superclassname = placeholder->supername();
729 havesupername = true;
730 }
731 }
732 }
733 }
734
735 // If the class is in the placeholder table, class loading is in progress
736 if (super_load_in_progress && havesupername==true) {
737 k = handle_parallel_super_load(name,
738 superclassname,
739 class_loader,
740 protection_domain,
741 lockObject, THREAD);
742 if (HAS_PENDING_EXCEPTION) {
743 return NULL;
744 }
745 if (k != NULL) {
746 class_has_been_loaded = true;
747 }
748 }
749
750 bool throw_circularity_error = false;
751 if (!class_has_been_loaded) {
752 bool load_instance_added = false;
753
754 // add placeholder entry to record loading instance class
755 // Five cases:
756 // All cases need to prevent modifying bootclasssearchpath
757 // in parallel with a classload of same classname
758 // Redefineclasses uses existence of the placeholder for the duration
759 // of the class load to prevent concurrent redefinition of not completely
760 // defined classes.
761 // case 1. traditional classloaders that rely on the classloader object lock
762 // - no other need for LOAD_INSTANCE
763 // case 2. traditional classloaders that break the classloader object lock
764 // as a deadlock workaround. Detection of this case requires that
765 // this check is done while holding the classloader object lock,
766 // and that lock is still held when calling classloader's loadClass.
767 // For these classloaders, we ensure that the first requestor
768 // completes the load and other requestors wait for completion.
769 // case 3. Bootstrap classloader - don't own objectLocker
770 // This classloader supports parallelism at the classloader level,
771 // but only allows a single load of a class/classloader pair.
772 // No performance benefit and no deadlock issues.
773 // case 4. parallelCapable user level classloaders - without objectLocker
774 // Allow parallel classloading of a class/classloader pair
775
776 {
777 MutexLocker mu(SystemDictionary_lock, THREAD);
778 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
779 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
780 if (oldprobe) {
781 // only need check_seen_thread once, not on each loop
782 // 6341374 java/lang/Instrument with -Xcomp
783 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
784 throw_circularity_error = true;
785 } else {
786 // case 1: traditional: should never see load_in_progress.
787 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
788
789 // case 3: bootstrap classloader: prevent futile classloading,
790 // wait on first requestor
791 if (class_loader.is_null()) {
792 SystemDictionary_lock->wait();
793 } else {
794 // case 2: traditional with broken classloader lock. wait on first
795 // requestor.
796 double_lock_wait(lockObject, THREAD);
797 }
798 // Check if classloading completed while we were waiting
799 InstanceKlass* check = find_class(d_hash, name, dictionary);
800 if (check != NULL) {
801 // Klass is already loaded, so just return it
802 k = check;
803 class_has_been_loaded = true;
804 }
805 // check if other thread failed to load and cleaned up
806 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
807 }
808 }
809 }
810 }
811 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
812 // case 4: parallelCapable: allow competing threads to try
813 // LOAD_INSTANCE in parallel
814
815 if (!throw_circularity_error && !class_has_been_loaded) {
816 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
817 load_instance_added = true;
818 // For class loaders that do not acquire the classloader object lock,
819 // if they did not catch another thread holding LOAD_INSTANCE,
820 // need a check analogous to the acquire ObjectLocker/find_class
821 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
822 // one final check if the load has already completed
823 // class loaders holding the ObjectLock shouldn't find the class here
824 InstanceKlass* check = find_class(d_hash, name, dictionary);
825 if (check != NULL) {
826 // Klass is already loaded, so return it after checking/adding protection domain
827 k = check;
828 class_has_been_loaded = true;
829 }
830 }
831 }
832
833 // must throw error outside of owning lock
834 if (throw_circularity_error) {
835 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
836 ResourceMark rm(THREAD);
837 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
838 }
839
840 if (!class_has_been_loaded) {
841
842 // Do actual loading
843 k = load_instance_class(name, class_loader, THREAD);
844
845 // If everything was OK (no exceptions, no null return value), and
846 // class_loader is NOT the defining loader, do a little more bookkeeping.
847 if (!HAS_PENDING_EXCEPTION && k != NULL &&
848 k->class_loader() != class_loader()) {
849
850 check_constraints(d_hash, k, class_loader, false, THREAD);
851
852 // Need to check for a PENDING_EXCEPTION again; check_constraints
853 // can throw but we may have to remove entry from the placeholder table below.
854 if (!HAS_PENDING_EXCEPTION) {
855 // Record dependency for non-parent delegation.
856 // This recording keeps the defining class loader of the klass (k) found
857 // from being unloaded while the initiating class loader is loaded
858 // even if the reference to the defining class loader is dropped
859 // before references to the initiating class loader.
860 loader_data->record_dependency(k);
861
862 { // Grabbing the Compile_lock prevents systemDictionary updates
863 // during compilations.
864 MutexLocker mu(Compile_lock, THREAD);
865 update_dictionary(d_hash, p_index, p_hash,
866 k, class_loader, THREAD);
867 }
868
869 if (JvmtiExport::should_post_class_load()) {
870 Thread *thread = THREAD;
871 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
872 JvmtiExport::post_class_load((JavaThread *) thread, k);
873 }
874 }
875 }
876 } // load_instance_class
877
878 if (load_instance_added == true) {
879 // clean up placeholder entries for LOAD_INSTANCE success or error
880 // This brackets the SystemDictionary updates for both defining
881 // and initiating loaders
882 MutexLocker mu(SystemDictionary_lock, THREAD);
883 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
884 SystemDictionary_lock->notify_all();
885 }
886 }
887
888 if (HAS_PENDING_EXCEPTION || k == NULL) {
889 return NULL;
890 }
891 if (class_load_start_event.should_commit()) {
892 post_class_load_event(&class_load_start_event, k, loader_data);
893 }
894 #ifdef ASSERT
895 {
896 ClassLoaderData* loader_data = k->class_loader_data();
897 MutexLocker mu(SystemDictionary_lock, THREAD);
898 InstanceKlass* kk = find_class(name, loader_data);
899 assert(kk == k, "should be present in dictionary");
900 }
901 #endif
902
903 // return if the protection domain in NULL
904 if (protection_domain() == NULL) return k;
905
906 // Check the protection domain has the right access
907 if (dictionary->is_valid_protection_domain(d_hash, name,
908 protection_domain)) {
909 return k;
910 }
911
912 // Verify protection domain. If it fails an exception is thrown
913 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
914
915 return k;
916 }
917
918
919 // This routine does not lock the system dictionary.
920 //
921 // Since readers don't hold a lock, we must make sure that system
922 // dictionary entries are only removed at a safepoint (when only one
923 // thread is running), and are added to in a safe way (all links must
924 // be updated in an MT-safe manner).
925 //
926 // Callers should be aware that an entry could be added just after
927 // _dictionary->bucket(index) is read here, so the caller will not see
928 // the new entry.
929
930 Klass* SystemDictionary::find(Symbol* class_name,
931 Handle class_loader,
932 Handle protection_domain,
933 TRAPS) {
934
935 // The result of this call should be consistent with the result
936 // of the call to resolve_instance_class_or_null().
937 // See evaluation 6790209 and 4474172 for more details.
938 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
939 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
940
941 if (loader_data == NULL) {
942 // If the ClassLoaderData has not been setup,
943 // then the class loader has no entries in the dictionary.
944 return NULL;
945 }
946
947 Dictionary* dictionary = loader_data->dictionary();
948 unsigned int d_hash = dictionary->compute_hash(class_name);
949 return dictionary->find(d_hash, class_name,
950 protection_domain);
951 }
952
953
954 // Look for a loaded instance or array klass by name. Do not do any loading.
955 // return NULL in case of error.
956 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
957 Handle class_loader,
958 Handle protection_domain,
959 TRAPS) {
960 Klass* k = NULL;
961 assert(class_name != NULL, "class name must be non NULL");
962
963 if (FieldType::is_array(class_name)) {
964 // The name refers to an array. Parse the name.
965 // dimension and object_key in FieldArrayInfo are assigned as a
966 // side-effect of this call
967 FieldArrayInfo fd;
968 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
969 if (t != T_OBJECT) {
970 k = Universe::typeArrayKlassObj(t);
971 } else {
972 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
973 }
974 if (k != NULL) {
975 k = k->array_klass_or_null(fd.dimension());
976 }
977 } else {
978 k = find(class_name, class_loader, protection_domain, THREAD);
979 }
980 return k;
981 }
982
983 // Note: this method is much like resolve_from_stream, but
984 // does not publish the classes via the SystemDictionary.
985 // Handles unsafe_DefineAnonymousClass and redefineclasses
986 // RedefinedClasses do not add to the class hierarchy
987 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
988 Handle class_loader,
989 Handle protection_domain,
990 ClassFileStream* st,
991 const InstanceKlass* unsafe_anonymous_host,
992 GrowableArray<Handle>* cp_patches,
993 TRAPS) {
994
995 EventClassLoad class_load_start_event;
996
997 ClassLoaderData* loader_data;
998 if (unsafe_anonymous_host != NULL) {
999 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1000 // as the unsafe_anonymous_host
1001 guarantee(unsafe_anonymous_host->class_loader() == class_loader(), "should be the same");
1002 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1003 } else {
1004 loader_data = ClassLoaderData::class_loader_data(class_loader());
1005 }
1006
1007 assert(st != NULL, "invariant");
1008 assert(st->need_verify(), "invariant");
1009
1010 // Parse stream and create a klass.
1011 // Note that we do this even though this klass might
1012 // already be present in the SystemDictionary, otherwise we would not
1013 // throw potential ClassFormatErrors.
1014
1015 InstanceKlass* k = KlassFactory::create_from_stream(st,
1016 class_name,
1017 loader_data,
1018 protection_domain,
1019 unsafe_anonymous_host,
1020 cp_patches,
1021 CHECK_NULL);
1022
1023 if (unsafe_anonymous_host != NULL && k != NULL) {
1024 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1025 // so that they can be unloaded when the mirror is no longer referenced.
1026 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1027
1028 {
1029 MutexLocker mu_r(Compile_lock, THREAD);
1030
1031 // Add to class hierarchy, initialize vtables, and do possible
1032 // deoptimizations.
1033 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1034 // But, do not add to dictionary.
1035 }
1036
1037 // Rewrite and patch constant pool here.
1038 k->link_class(CHECK_NULL);
1039 if (cp_patches != NULL) {
1040 k->constants()->patch_resolved_references(cp_patches);
1041 }
1042
1043 // If it's anonymous, initialize it now, since nobody else will.
1044 k->eager_initialize(CHECK_NULL);
1045
1046 // notify jvmti
1047 if (JvmtiExport::should_post_class_load()) {
1048 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1049 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1050 }
1051 if (class_load_start_event.should_commit()) {
1052 post_class_load_event(&class_load_start_event, k, loader_data);
1053 }
1054 }
1055 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1056 "cp_patches only found with unsafe_anonymous_host");
1057
1058 return k;
1059 }
1060
1061 // Add a klass to the system from a stream (called by jni_DefineClass and
1062 // JVM_DefineClass).
1063 // Note: class_name can be NULL. In that case we do not know the name of
1064 // the class until we have parsed the stream.
1065
1066 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1067 Handle class_loader,
1068 Handle protection_domain,
1069 ClassFileStream* st,
1070 TRAPS) {
1071
1072 HandleMark hm(THREAD);
1073
1074 // Classloaders that support parallelism, e.g. bootstrap classloader,
1075 // do not acquire lock here
1076 bool DoObjectLock = true;
1077 if (is_parallelCapable(class_loader)) {
1078 DoObjectLock = false;
1079 }
1080
1081 ClassLoaderData* loader_data = register_loader(class_loader);
1082
1083 // Make sure we are synchronized on the class loader before we proceed
1084 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1085 check_loader_lock_contention(lockObject, THREAD);
1086 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1087
1088 assert(st != NULL, "invariant");
1089
1090 // Parse the stream and create a klass.
1091 // Note that we do this even though this klass might
1092 // already be present in the SystemDictionary, otherwise we would not
1093 // throw potential ClassFormatErrors.
1094 InstanceKlass* k = NULL;
1095
1096 #if INCLUDE_CDS
1097 if (!DumpSharedSpaces) {
1098 k = SystemDictionaryShared::lookup_from_stream(class_name,
1099 class_loader,
1100 protection_domain,
1101 st,
1102 CHECK_NULL);
1103 }
1104 #endif
1105
1106 if (k == NULL) {
1107 if (st->buffer() == NULL) {
1108 return NULL;
1109 }
1110 k = KlassFactory::create_from_stream(st,
1111 class_name,
1112 loader_data,
1113 protection_domain,
1114 NULL, // unsafe_anonymous_host
1115 NULL, // cp_patches
1116 CHECK_NULL);
1117 }
1118
1119 assert(k != NULL, "no klass created");
1120 Symbol* h_name = k->name();
1121 assert(class_name == NULL || class_name == h_name, "name mismatch");
1122
1123 // Add class just loaded
1124 // If a class loader supports parallel classloading handle parallel define requests
1125 // find_or_define_instance_class may return a different InstanceKlass
1126 if (is_parallelCapable(class_loader)) {
1127 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1128 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1129 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1130 assert(defined_k != NULL, "Should have a klass if there's no exception");
1131 loader_data->add_to_deallocate_list(k);
1132 k = defined_k;
1133 }
1134 } else {
1135 define_instance_class(k, THREAD);
1136 }
1137
1138 // If defining the class throws an exception register 'k' for cleanup.
1139 if (HAS_PENDING_EXCEPTION) {
1140 assert(k != NULL, "Must have an instance klass here!");
1141 loader_data->add_to_deallocate_list(k);
1142 return NULL;
1143 }
1144
1145 // Make sure we have an entry in the SystemDictionary on success
1146 debug_only( {
1147 MutexLocker mu(SystemDictionary_lock, THREAD);
1148
1149 Klass* check = find_class(h_name, k->class_loader_data());
1150 assert(check == k, "should be present in the dictionary");
1151 } );
1152
1153 return k;
1154 }
1155
1156 #if INCLUDE_CDS
1157 // Load a class for boot loader from the shared spaces. This also
1158 // forces the super class and all interfaces to be loaded.
1159 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1160 TRAPS) {
1161 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1162 if (ik != NULL && ik->is_shared_boot_class()) {
1163 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1164 }
1165 return NULL;
1166 }
1167
1168 // Check if a shared class can be loaded by the specific classloader:
1169 //
1170 // NULL classloader:
1171 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1172 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1173 // be defined in an unnamed module.
1174 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1175 InstanceKlass* ik,
1176 Handle class_loader, TRAPS) {
1177 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1178 "Cannot use sharing if java.base is patched");
1179 ResourceMark rm(THREAD);
1180 int path_index = ik->shared_classpath_index();
1181 ClassLoaderData* loader_data = class_loader_data(class_loader);
1182 if (path_index < 0) {
1183 // path_index < 0 indicates that the class is intended for a custom loader
1184 // and should not be loaded by boot/platform/app loaders
1185 if (loader_data->is_builtin_class_loader_data()) {
1186 return false;
1187 } else {
1188 return true;
1189 }
1190 }
1191 SharedClassPathEntry* ent =
1192 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1193 if (!Universe::is_module_initialized()) {
1194 assert(ent != NULL && ent->is_modules_image(),
1195 "Loading non-bootstrap classes before the module system is initialized");
1196 assert(class_loader.is_null(), "sanity");
1197 return true;
1198 }
1199 // Get the pkg_entry from the classloader
1200 TempNewSymbol pkg_name = NULL;
1201 PackageEntry* pkg_entry = NULL;
1202 ModuleEntry* mod_entry = NULL;
1203 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1204 if (pkg_name != NULL) {
1205 if (loader_data != NULL) {
1206 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1207 }
1208 if (pkg_entry != NULL) {
1209 mod_entry = pkg_entry->module();
1210 }
1211 }
1212
1213 // If the archived class is from a module that has been patched at runtime,
1214 // the class cannot be loaded from the archive.
1215 if (mod_entry != NULL && mod_entry->is_patched()) {
1216 return false;
1217 }
1218
1219 if (class_loader.is_null()) {
1220 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1221 // The NULL classloader can load archived class originated from the
1222 // "modules" jimage and the -Xbootclasspath/a. For class from the
1223 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1224 // by the NULL classloader.
1225 if (mod_entry != NULL) {
1226 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1227 // ModuleEntry's location agrees with the archived class' origination.
1228 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1229 return true; // Module class from the "module" jimage
1230 }
1231 }
1232
1233 // If the archived class is not from the "module" jimage, the class can be
1234 // loaded by the NULL classloader if
1235 //
1236 // 1. the class is from the unamed package
1237 // 2. or, the class is not from a module defined in the NULL classloader
1238 // 3. or, the class is from an unamed module
1239 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1240 // the class is from the -Xbootclasspath/a
1241 if (pkg_name == NULL ||
1242 pkg_entry == NULL ||
1243 pkg_entry->in_unnamed_module()) {
1244 assert(mod_entry == NULL ||
1245 mod_entry == loader_data->unnamed_module(),
1246 "the unnamed module is not defined in the classloader");
1247 return true;
1248 }
1249 }
1250 return false;
1251 } else {
1252 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1253 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1254 return res;
1255 }
1256 }
1257
1258 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1259 Handle class_loader,
1260 Handle protection_domain,
1261 const ClassFileStream *cfs,
1262 TRAPS) {
1263 assert(ik != NULL, "sanity");
1264 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1265 Symbol* class_name = ik->name();
1266
1267 bool visible = is_shared_class_visible(
1268 class_name, ik, class_loader, CHECK_NULL);
1269 if (!visible) {
1270 return NULL;
1271 }
1272
1273 // Resolve the superclass and interfaces. They must be the same
1274 // as in dump time, because the layout of <ik> depends on
1275 // the specific layout of ik->super() and ik->local_interfaces().
1276 //
1277 // If unexpected superclass or interfaces are found, we cannot
1278 // load <ik> from the shared archive.
1279
1280 if (ik->super() != NULL) {
1281 Symbol* cn = ik->super()->name();
1282 Klass *s = resolve_super_or_fail(class_name, cn,
1283 class_loader, protection_domain, true, CHECK_NULL);
1284 if (s != ik->super()) {
1285 // The dynamically resolved super class is not the same as the one we used during dump time,
1286 // so we cannot use ik.
1287 return NULL;
1288 } else {
1289 assert(s->is_shared(), "must be");
1290 }
1291 }
1292
1293 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1294 int num_interfaces = interfaces->length();
1295 for (int index = 0; index < num_interfaces; index++) {
1296 InstanceKlass* k = interfaces->at(index);
1297 Symbol* name = k->name();
1298 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1299 if (k != i) {
1300 // The dynamically resolved interface class is not the same as the one we used during dump time,
1301 // so we cannot use ik.
1302 return NULL;
1303 } else {
1304 assert(i->is_shared(), "must be");
1305 }
1306 }
1307
1308 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1309 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1310 if (new_ik != NULL) {
1311 // The class is changed by CFLH. Return the new class. The shared class is
1312 // not used.
1313 return new_ik;
1314 }
1315
1316 // Adjust methods to recover missing data. They need addresses for
1317 // interpreter entry points and their default native method address
1318 // must be reset.
1319
1320 // Updating methods must be done under a lock so multiple
1321 // threads don't update these in parallel
1322 //
1323 // Shared classes are all currently loaded by either the bootstrap or
1324 // internal parallel class loaders, so this will never cause a deadlock
1325 // on a custom class loader lock.
1326
1327 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1328 {
1329 HandleMark hm(THREAD);
1330 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1331 check_loader_lock_contention(lockObject, THREAD);
1332 ObjectLocker ol(lockObject, THREAD, true);
1333 // prohibited package check assumes all classes loaded from archive call
1334 // restore_unshareable_info which calls ik->set_package()
1335 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1336 }
1337
1338 ik->print_class_load_logging(loader_data, NULL, NULL);
1339
1340 // For boot loader, ensure that GetSystemPackage knows that a class in this
1341 // package was loaded.
1342 if (class_loader.is_null()) {
1343 int path_index = ik->shared_classpath_index();
1344 ResourceMark rm(THREAD);
1345 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1346 }
1347
1348 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1349 // Only dump the classes that can be stored into CDS archive
1350 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1351 ResourceMark rm(THREAD);
1352 classlist_file->print_cr("%s", ik->name()->as_C_string());
1353 classlist_file->flush();
1354 }
1355 }
1356
1357 // notify a class loaded from shared object
1358 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1359
1360 ik->set_has_passed_fingerprint_check(false);
1361 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1362 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1363 uint64_t cds_fp = ik->get_stored_fingerprint();
1364 if (aot_fp != 0 && aot_fp == cds_fp) {
1365 // This class matches with a class saved in an AOT library
1366 ik->set_has_passed_fingerprint_check(true);
1367 } else {
1368 if (log_is_enabled(Info, class, fingerprint)) {
1369 ResourceMark rm(THREAD);
1370 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1371 }
1372 }
1373 }
1374
1375 return ik;
1376 }
1377 #endif // INCLUDE_CDS
1378
1379 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1380
1381 if (class_loader.is_null()) {
1382 ResourceMark rm(THREAD);
1383 PackageEntry* pkg_entry = NULL;
1384 bool search_only_bootloader_append = false;
1385 ClassLoaderData *loader_data = class_loader_data(class_loader);
1386
1387 // Find the package in the boot loader's package entry table.
1388 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1389 if (pkg_name != NULL) {
1390 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1391 }
1392
1393 // Prior to attempting to load the class, enforce the boot loader's
1394 // visibility boundaries.
1395 if (!Universe::is_module_initialized()) {
1396 // During bootstrapping, prior to module initialization, any
1397 // class attempting to be loaded must be checked against the
1398 // java.base packages in the boot loader's PackageEntryTable.
1399 // No class outside of java.base is allowed to be loaded during
1400 // this bootstrapping window.
1401 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1402 // Class is either in the unnamed package or in
1403 // a named package within the unnamed module. Either
1404 // case is outside of java.base, do not attempt to
1405 // load the class post java.base definition. If
1406 // java.base has not been defined, let the class load
1407 // and its package will be checked later by
1408 // ModuleEntryTable::verify_javabase_packages.
1409 if (ModuleEntryTable::javabase_defined()) {
1410 return NULL;
1411 }
1412 } else {
1413 // Check that the class' package is defined within java.base.
1414 ModuleEntry* mod_entry = pkg_entry->module();
1415 Symbol* mod_entry_name = mod_entry->name();
1416 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1417 return NULL;
1418 }
1419 }
1420 } else {
1421 // After the module system has been initialized, check if the class'
1422 // package is in a module defined to the boot loader.
1423 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1424 // Class is either in the unnamed package, in a named package
1425 // within a module not defined to the boot loader or in a
1426 // a named package within the unnamed module. In all cases,
1427 // limit visibility to search for the class only in the boot
1428 // loader's append path.
1429 if (!ClassLoader::has_bootclasspath_append()) {
1430 // If there is no bootclasspath append entry, no need to continue
1431 // searching.
1432 return NULL;
1433 }
1434 search_only_bootloader_append = true;
1435 }
1436 }
1437
1438 // Prior to bootstrapping's module initialization, never load a class outside
1439 // of the boot loader's module path
1440 assert(Universe::is_module_initialized() ||
1441 !search_only_bootloader_append,
1442 "Attempt to load a class outside of boot loader's module path");
1443
1444 // Search for classes in the CDS archive.
1445 InstanceKlass* k = NULL;
1446 {
1447 #if INCLUDE_CDS
1448 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1449 k = load_shared_boot_class(class_name, THREAD);
1450 #endif
1451 }
1452
1453 if (k == NULL) {
1454 // Use VM class loader
1455 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1456 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1457 }
1458
1459 // find_or_define_instance_class may return a different InstanceKlass
1460 if (k != NULL) {
1461 InstanceKlass* defined_k =
1462 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1463 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1464 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1465 assert(defined_k != NULL, "Should have a klass if there's no exception");
1466 loader_data->add_to_deallocate_list(k);
1467 k = defined_k;
1468 } else if (HAS_PENDING_EXCEPTION) {
1469 loader_data->add_to_deallocate_list(k);
1470 return NULL;
1471 }
1472 }
1473 return k;
1474 } else {
1475 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1476 ResourceMark rm(THREAD);
1477
1478 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1479 JavaThread* jt = (JavaThread*) THREAD;
1480
1481 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1482 ClassLoader::perf_app_classload_selftime(),
1483 ClassLoader::perf_app_classload_count(),
1484 jt->get_thread_stat()->perf_recursion_counts_addr(),
1485 jt->get_thread_stat()->perf_timers_addr(),
1486 PerfClassTraceTime::CLASS_LOAD);
1487
1488 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1489 // Translate to external class name format, i.e., convert '/' chars to '.'
1490 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1491
1492 JavaValue result(T_OBJECT);
1493
1494 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1495
1496 // Call public unsynchronized loadClass(String) directly for all class loaders.
1497 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1498 // acquire a class-name based lock rather than the class loader object lock.
1499 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1500 JavaCalls::call_virtual(&result,
1501 class_loader,
1502 spec_klass,
1503 vmSymbols::loadClass_name(),
1504 vmSymbols::string_class_signature(),
1505 string,
1506 CHECK_NULL);
1507
1508 assert(result.get_type() == T_OBJECT, "just checking");
1509 oop obj = (oop) result.get_jobject();
1510
1511 // Primitive classes return null since forName() can not be
1512 // used to obtain any of the Class objects representing primitives or void
1513 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1514 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1515 // For user defined Java class loaders, check that the name returned is
1516 // the same as that requested. This check is done for the bootstrap
1517 // loader when parsing the class file.
1518 if (class_name == k->name()) {
1519 return k;
1520 }
1521 }
1522 // Class is not found or has the wrong name, return NULL
1523 return NULL;
1524 }
1525 }
1526
1527 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1528 EventClassDefine event;
1529 if (event.should_commit()) {
1530 event.set_definedClass(k);
1531 event.set_definingClassLoader(def_cld);
1532 event.commit();
1533 }
1534 }
1535
1536 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1537
1538 HandleMark hm(THREAD);
1539 ClassLoaderData* loader_data = k->class_loader_data();
1540 Handle class_loader_h(THREAD, loader_data->class_loader());
1541
1542 // for bootstrap and other parallel classloaders don't acquire lock,
1543 // use placeholder token
1544 // If a parallelCapable class loader calls define_instance_class instead of
1545 // find_or_define_instance_class to get here, we have a timing
1546 // hole with systemDictionary updates and check_constraints
1547 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1548 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1549 compute_loader_lock_object(class_loader_h, THREAD)),
1550 "define called without lock");
1551 }
1552
1553 // Check class-loading constraints. Throw exception if violation is detected.
1554 // Grabs and releases SystemDictionary_lock
1555 // The check_constraints/find_class call and update_dictionary sequence
1556 // must be "atomic" for a specific class/classloader pair so we never
1557 // define two different instanceKlasses for that class/classloader pair.
1558 // Existing classloaders will call define_instance_class with the
1559 // classloader lock held
1560 // Parallel classloaders will call find_or_define_instance_class
1561 // which will require a token to perform the define class
1562 Symbol* name_h = k->name();
1563 Dictionary* dictionary = loader_data->dictionary();
1564 unsigned int d_hash = dictionary->compute_hash(name_h);
1565 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1566
1567 // Register class just loaded with class loader (placed in Vector)
1568 // Note we do this before updating the dictionary, as this can
1569 // fail with an OutOfMemoryError (if it does, we will *not* put this
1570 // class in the dictionary and will not update the class hierarchy).
1571 // JVMTI FollowReferences needs to find the classes this way.
1572 if (k->class_loader() != NULL) {
1573 methodHandle m(THREAD, Universe::loader_addClass_method());
1574 JavaValue result(T_VOID);
1575 JavaCallArguments args(class_loader_h);
1576 args.push_oop(Handle(THREAD, k->java_mirror()));
1577 JavaCalls::call(&result, m, &args, CHECK);
1578 }
1579
1580 // Add the new class. We need recompile lock during update of CHA.
1581 {
1582 unsigned int p_hash = placeholders()->compute_hash(name_h);
1583 int p_index = placeholders()->hash_to_index(p_hash);
1584
1585 MutexLocker mu_r(Compile_lock, THREAD);
1586
1587 // Add to class hierarchy, initialize vtables, and do possible
1588 // deoptimizations.
1589 add_to_hierarchy(k, CHECK); // No exception, but can block
1590
1591 // Add to systemDictionary - so other classes can see it.
1592 // Grabs and releases SystemDictionary_lock
1593 update_dictionary(d_hash, p_index, p_hash,
1594 k, class_loader_h, THREAD);
1595 }
1596 k->eager_initialize(THREAD);
1597
1598 // notify jvmti
1599 if (JvmtiExport::should_post_class_load()) {
1600 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1601 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1602
1603 }
1604 post_class_define_event(k, loader_data);
1605 }
1606
1607 // Support parallel classloading
1608 // All parallel class loaders, including bootstrap classloader
1609 // lock a placeholder entry for this class/class_loader pair
1610 // to allow parallel defines of different classes for this class loader
1611 // With AllowParallelDefine flag==true, in case they do not synchronize around
1612 // FindLoadedClass/DefineClass, calls, we check for parallel
1613 // loading for them, wait if a defineClass is in progress
1614 // and return the initial requestor's results
1615 // This flag does not apply to the bootstrap classloader.
1616 // With AllowParallelDefine flag==false, call through to define_instance_class
1617 // which will throw LinkageError: duplicate class definition.
1618 // False is the requested default.
1619 // For better performance, the class loaders should synchronize
1620 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1621 // potentially waste time reading and parsing the bytestream.
1622 // Note: VM callers should ensure consistency of k/class_name,class_loader
1623 // Be careful when modifying this code: once you have run
1624 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1625 // you need to find_and_remove it before returning.
1626 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1627 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1628 InstanceKlass* k, TRAPS) {
1629
1630 Symbol* name_h = k->name(); // passed in class_name may be null
1631 ClassLoaderData* loader_data = class_loader_data(class_loader);
1632 Dictionary* dictionary = loader_data->dictionary();
1633
1634 unsigned int d_hash = dictionary->compute_hash(name_h);
1635
1636 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1637 unsigned int p_hash = placeholders()->compute_hash(name_h);
1638 int p_index = placeholders()->hash_to_index(p_hash);
1639 PlaceholderEntry* probe;
1640
1641 {
1642 MutexLocker mu(SystemDictionary_lock, THREAD);
1643 // First check if class already defined
1644 if (is_parallelDefine(class_loader)) {
1645 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1646 if (check != NULL) {
1647 return check;
1648 }
1649 }
1650
1651 // Acquire define token for this class/classloader
1652 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1653 // Wait if another thread defining in parallel
1654 // All threads wait - even those that will throw duplicate class: otherwise
1655 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1656 // if other thread has not finished updating dictionary
1657 while (probe->definer() != NULL) {
1658 SystemDictionary_lock->wait();
1659 }
1660 // Only special cases allow parallel defines and can use other thread's results
1661 // Other cases fall through, and may run into duplicate defines
1662 // caught by finding an entry in the SystemDictionary
1663 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1664 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1665 SystemDictionary_lock->notify_all();
1666 #ifdef ASSERT
1667 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1668 assert(check != NULL, "definer missed recording success");
1669 #endif
1670 return probe->instance_klass();
1671 } else {
1672 // This thread will define the class (even if earlier thread tried and had an error)
1673 probe->set_definer(THREAD);
1674 }
1675 }
1676
1677 define_instance_class(k, THREAD);
1678
1679 Handle linkage_exception = Handle(); // null handle
1680
1681 // definer must notify any waiting threads
1682 {
1683 MutexLocker mu(SystemDictionary_lock, THREAD);
1684 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1685 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1686 if (probe != NULL) {
1687 if (HAS_PENDING_EXCEPTION) {
1688 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1689 CLEAR_PENDING_EXCEPTION;
1690 } else {
1691 probe->set_instance_klass(k);
1692 }
1693 probe->set_definer(NULL);
1694 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1695 SystemDictionary_lock->notify_all();
1696 }
1697 }
1698
1699 // Can't throw exception while holding lock due to rank ordering
1700 if (linkage_exception() != NULL) {
1701 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1702 }
1703
1704 return k;
1705 }
1706
1707 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1708 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1709 if (class_loader.is_null()) {
1710 return Handle(THREAD, _system_loader_lock_obj);
1711 } else {
1712 return class_loader;
1713 }
1714 }
1715
1716 // This method is added to check how often we have to wait to grab loader
1717 // lock. The results are being recorded in the performance counters defined in
1718 // ClassLoader::_sync_systemLoaderLockContentionRate and
1719 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1720 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1721 if (!UsePerfData) {
1722 return;
1723 }
1724
1725 assert(!loader_lock.is_null(), "NULL lock object");
1726
1727 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1728 == ObjectSynchronizer::owner_other) {
1729 // contention will likely happen, so increment the corresponding
1730 // contention counter.
1731 if (loader_lock() == _system_loader_lock_obj) {
1732 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1733 } else {
1734 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1735 }
1736 }
1737 }
1738
1739 // ----------------------------------------------------------------------------
1740 // Lookup
1741
1742 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1743 Symbol* class_name,
1744 Dictionary* dictionary) {
1745 assert_locked_or_safepoint(SystemDictionary_lock);
1746 int index = dictionary->hash_to_index(hash);
1747 return dictionary->find_class(index, hash, class_name);
1748 }
1749
1750
1751 // Basic find on classes in the midst of being loaded
1752 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1753 ClassLoaderData* loader_data) {
1754 assert_locked_or_safepoint(SystemDictionary_lock);
1755 unsigned int p_hash = placeholders()->compute_hash(class_name);
1756 int p_index = placeholders()->hash_to_index(p_hash);
1757 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1758 }
1759
1760
1761 // Used for assertions and verification only
1762 // Precalculating the hash and index is an optimization because there are many lookups
1763 // before adding the class.
1764 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1765 assert_locked_or_safepoint(SystemDictionary_lock);
1766 #ifndef ASSERT
1767 guarantee(VerifyBeforeGC ||
1768 VerifyDuringGC ||
1769 VerifyBeforeExit ||
1770 VerifyDuringStartup ||
1771 VerifyAfterGC, "too expensive");
1772 #endif
1773
1774 Dictionary* dictionary = loader_data->dictionary();
1775 unsigned int d_hash = dictionary->compute_hash(class_name);
1776 return find_class(d_hash, class_name, dictionary);
1777 }
1778
1779
1780 // ----------------------------------------------------------------------------
1781 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1782 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1783 // before a new class is used.
1784
1785 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1786 assert(k != NULL, "just checking");
1787 assert_locked_or_safepoint(Compile_lock);
1788
1789 k->set_init_state(InstanceKlass::loaded);
1790 // make sure init_state store is already done.
1791 // The compiler reads the hierarchy outside of the Compile_lock.
1792 // Access ordering is used to add to hierarchy.
1793
1794 // Link into hierachy.
1795 k->append_to_sibling_list(); // add to superklass/sibling list
1796 k->process_interfaces(THREAD); // handle all "implements" declarations
1797
1798 // Now flush all code that depended on old class hierarchy.
1799 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1800 CodeCache::flush_dependents_on(k);
1801 }
1802
1803 // ----------------------------------------------------------------------------
1804 // GC support
1805
1806 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1807 // Note: anonymous classes are not in the SD.
1808 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1809
1810 bool unloading_occurred;
1811 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1812 {
1813 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1814 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1815 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1816 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1817 if (unloading_occurred) {
1818 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1819 JFR_ONLY(Jfr::on_unloading_classes();)
1820
1821 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1822 ClassLoaderDataGraph::clean_module_and_package_info();
1823 constraints()->purge_loader_constraints();
1824 resolution_errors()->purge_resolution_errors();
1825 }
1826 }
1827
1828 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1829
1830 if (unloading_occurred) {
1831 SymbolTable::trigger_cleanup();
1832
1833 // Oops referenced by the protection domain cache table may get unreachable independently
1834 // of the class loader (eg. cached protection domain oops). So we need to
1835 // explicitly unlink them here.
1836 // All protection domain oops are linked to the caller class, so if nothing
1837 // unloads, this is not needed.
1838 _pd_cache_table->trigger_cleanup();
1839 }
1840
1841 return unloading_occurred;
1842 }
1843
1844 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1845 f->do_oop(&_java_system_loader);
1846 f->do_oop(&_java_platform_loader);
1847 f->do_oop(&_system_loader_lock_obj);
1848 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1849
1850 // Visit extra methods
1851 invoke_method_table()->oops_do(f);
1852
1853 if (include_handles) {
1854 OopStorageSet::vm_global()->oops_do(f);
1855 }
1856 }
1857
1858 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1859 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1860 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1861 it->push(well_known_klass_addr((WKID)id));
1862 }
1863 }
1864
1865 void SystemDictionary::methods_do(void f(Method*)) {
1866 // Walk methods in loaded classes
1867 MutexLocker ml(ClassLoaderDataGraph_lock);
1868 ClassLoaderDataGraph::methods_do(f);
1869 // Walk method handle intrinsics
1870 invoke_method_table()->methods_do(f);
1871 }
1872
1873 // ----------------------------------------------------------------------------
1874 // Initialization
1875
1876 void SystemDictionary::initialize(TRAPS) {
1877 // Allocate arrays
1878 _placeholders = new PlaceholderTable(_placeholder_table_size);
1879 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1880 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1881 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1882 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1883
1884 // Allocate private object used as system class loader lock
1885 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1886 // Initialize basic classes
1887 resolve_well_known_classes(CHECK);
1888 }
1889
1890 // Compact table of directions on the initialization of klasses:
1891 static const short wk_init_info[] = {
1892 #define WK_KLASS_INIT_INFO(name, symbol) \
1893 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1894
1895 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1896 #undef WK_KLASS_INIT_INFO
1897 0
1898 };
1899
1900 #ifdef ASSERT
1901 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1902 int sid;
1903 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1904 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1905 if (class_name == symbol) {
1906 return true;
1907 }
1908 }
1909 return false;
1910 }
1911 #endif
1912
1913 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1914 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1915 int sid = wk_init_info[id - FIRST_WKID];
1916 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1917 InstanceKlass** klassp = &_well_known_klasses[id];
1918
1919 if ((*klassp) == NULL) {
1920 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1921 (*klassp) = InstanceKlass::cast(k);
1922 }
1923 return ((*klassp) != NULL);
1924 }
1925
1926 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1927 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1928 for (int id = (int)start_id; id < (int)limit_id; id++) {
1929 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1930 resolve_wk_klass((WKID)id, CHECK);
1931 }
1932
1933 // move the starting value forward to the limit:
1934 start_id = limit_id;
1935 }
1936
1937 void SystemDictionary::resolve_well_known_classes(TRAPS) {
1938 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
1939
1940 // Create the ModuleEntry for java.base. This call needs to be done here,
1941 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1942 ClassLoader::classLoader_init2(CHECK);
1943
1944 // Preload commonly used klasses
1945 WKID scan = FIRST_WKID;
1946 // first do Object, then String, Class
1947 #if INCLUDE_CDS
1948 if (UseSharedSpaces) {
1949 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1950
1951 // It's unsafe to access the archived heap regions before they
1952 // are fixed up, so we must do the fixup as early as possible
1953 // before the archived java objects are accessed by functions
1954 // such as java_lang_Class::restore_archived_mirror and
1955 // ConstantPool::restore_unshareable_info (restores the archived
1956 // resolved_references array object).
1957 //
1958 // HeapShared::fixup_mapped_heap_regions() fills the empty
1959 // spaces in the archived heap regions and may use
1960 // SystemDictionary::Object_klass(), so we can do this only after
1961 // Object_klass is resolved. See the above resolve_wk_klasses_through()
1962 // call. No mirror objects are accessed/restored in the above call.
1963 // Mirrors are restored after java.lang.Class is loaded.
1964 HeapShared::fixup_mapped_heap_regions();
1965
1966 // Initialize the constant pool for the Object_class
1967 assert(Object_klass()->is_shared(), "must be");
1968 Object_klass()->constants()->restore_unshareable_info(CHECK);
1969 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1970 } else
1971 #endif
1972 {
1973 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1974 }
1975
1976 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
1977
1978 java_lang_Object::register_natives(CHECK);
1979
1980 // Calculate offsets for String and Class classes since they are loaded and
1981 // can be used after this point.
1982 java_lang_String::compute_offsets();
1983 java_lang_Class::compute_offsets();
1984
1985 // Fixup mirrors for classes loaded before java.lang.Class.
1986 // These calls iterate over the objects currently in the perm gen
1987 // so calling them at this point is matters (not before when there
1988 // are fewer objects and not later after there are more objects
1989 // in the perm gen.
1990 Universe::initialize_basic_type_mirrors(CHECK);
1991 Universe::fixup_mirrors(CHECK);
1992
1993 // do a bunch more:
1994 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1995
1996 // Preload ref klasses and set reference types
1997 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
1998 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1999
2000 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2001 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2002 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2003 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2004 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2005
2006 // JSR 292 classes
2007 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2008 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2009 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2010 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2011 WKID last = WKID_LIMIT;
2012 resolve_wk_klasses_until(last, scan, CHECK);
2013
2014 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2015 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2016 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2017 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2018 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2019 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2020 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2021 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2022 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2023 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2024
2025 #ifdef ASSERT
2026 if (UseSharedSpaces) {
2027 assert(JvmtiExport::is_early_phase(),
2028 "All well known classes must be resolved in JVMTI early phase");
2029 for (int i = FIRST_WKID; i < last; i++) {
2030 InstanceKlass* k = _well_known_klasses[i];
2031 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2032 }
2033 }
2034 #endif
2035 }
2036
2037 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2038 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2039 BasicType SystemDictionary::box_klass_type(Klass* k) {
2040 assert(k != NULL, "");
2041 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2042 if (_box_klasses[i] == k)
2043 return (BasicType)i;
2044 }
2045 return T_OBJECT;
2046 }
2047
2048 // Constraints on class loaders. The details of the algorithm can be
2049 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2050 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2051 // that the dictionary needs to maintain a set of contraints that
2052 // must be satisfied by all classes in the dictionary.
2053 // if defining is true, then LinkageError if already in dictionary
2054 // if initiating loader, then ok if InstanceKlass matches existing entry
2055
2056 void SystemDictionary::check_constraints(unsigned int d_hash,
2057 InstanceKlass* k,
2058 Handle class_loader,
2059 bool defining,
2060 TRAPS) {
2061 ResourceMark rm(THREAD);
2062 stringStream ss;
2063 bool throwException = false;
2064
2065 {
2066 Symbol *name = k->name();
2067 ClassLoaderData *loader_data = class_loader_data(class_loader);
2068
2069 MutexLocker mu(SystemDictionary_lock, THREAD);
2070
2071 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2072 if (check != NULL) {
2073 // If different InstanceKlass - duplicate class definition,
2074 // else - ok, class loaded by a different thread in parallel.
2075 // We should only have found it if it was done loading and ok to use.
2076 // The dictionary only holds instance classes, placeholders
2077 // also hold array classes.
2078
2079 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2080 if ((defining == true) || (k != check)) {
2081 throwException = true;
2082 ss.print("loader %s", loader_data->loader_name_and_id());
2083 ss.print(" attempted duplicate %s definition for %s. (%s)",
2084 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2085 } else {
2086 return;
2087 }
2088 }
2089
2090 #ifdef ASSERT
2091 Symbol* ph_check = find_placeholder(name, loader_data);
2092 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2093 #endif
2094
2095 if (throwException == false) {
2096 if (constraints()->check_or_update(k, class_loader, name) == false) {
2097 throwException = true;
2098 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2099 ss.print(" wants to load %s %s.",
2100 k->external_kind(), k->external_name());
2101 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2102 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2103 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2104 existing_klass->external_kind(),
2105 existing_klass->class_loader_data()->loader_name_and_id(),
2106 existing_klass->class_in_module_of_loader(false, true));
2107 } else {
2108 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2109 }
2110 }
2111 }
2112 }
2113
2114 // Throw error now if needed (cannot throw while holding
2115 // SystemDictionary_lock because of rank ordering)
2116 if (throwException == true) {
2117 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2118 }
2119 }
2120
2121 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2122 // have been called.
2123 void SystemDictionary::update_dictionary(unsigned int d_hash,
2124 int p_index, unsigned int p_hash,
2125 InstanceKlass* k,
2126 Handle class_loader,
2127 TRAPS) {
2128 // Compile_lock prevents systemDictionary updates during compilations
2129 assert_locked_or_safepoint(Compile_lock);
2130 Symbol* name = k->name();
2131 ClassLoaderData *loader_data = class_loader_data(class_loader);
2132
2133 {
2134 MutexLocker mu1(SystemDictionary_lock, THREAD);
2135
2136 // Make a new dictionary entry.
2137 Dictionary* dictionary = loader_data->dictionary();
2138 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2139 if (sd_check == NULL) {
2140 dictionary->add_klass(d_hash, name, k);
2141 }
2142 #ifdef ASSERT
2143 sd_check = find_class(d_hash, name, dictionary);
2144 assert (sd_check != NULL, "should have entry in dictionary");
2145 // Note: there may be a placeholder entry: for circularity testing
2146 // or for parallel defines
2147 #endif
2148 SystemDictionary_lock->notify_all();
2149 }
2150 }
2151
2152
2153 // Try to find a class name using the loader constraints. The
2154 // loader constraints might know about a class that isn't fully loaded
2155 // yet and these will be ignored.
2156 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2157 Symbol* class_name, Handle class_loader, TRAPS) {
2158
2159 // First see if it has been loaded directly.
2160 // Force the protection domain to be null. (This removes protection checks.)
2161 Handle no_protection_domain;
2162 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2163 no_protection_domain, CHECK_NULL);
2164 if (klass != NULL)
2165 return klass;
2166
2167 // Now look to see if it has been loaded elsewhere, and is subject to
2168 // a loader constraint that would require this loader to return the
2169 // klass that is already loaded.
2170 if (FieldType::is_array(class_name)) {
2171 // For array classes, their Klass*s are not kept in the
2172 // constraint table. The element Klass*s are.
2173 FieldArrayInfo fd;
2174 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2175 if (t != T_OBJECT) {
2176 klass = Universe::typeArrayKlassObj(t);
2177 } else {
2178 MutexLocker mu(SystemDictionary_lock, THREAD);
2179 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2180 }
2181 // If element class already loaded, allocate array klass
2182 if (klass != NULL) {
2183 klass = klass->array_klass_or_null(fd.dimension());
2184 }
2185 } else {
2186 MutexLocker mu(SystemDictionary_lock, THREAD);
2187 // Non-array classes are easy: simply check the constraint table.
2188 klass = constraints()->find_constrained_klass(class_name, class_loader);
2189 }
2190
2191 return klass;
2192 }
2193
2194
2195 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2196 Handle class_loader1,
2197 Handle class_loader2,
2198 Thread* THREAD) {
2199 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2200 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2201
2202 Symbol* constraint_name = NULL;
2203 // Needs to be in same scope as constraint_name in case a Symbol is created and
2204 // assigned to constraint_name.
2205 FieldArrayInfo fd;
2206 if (!FieldType::is_array(class_name)) {
2207 constraint_name = class_name;
2208 } else {
2209 // For array classes, their Klass*s are not kept in the
2210 // constraint table. The element classes are.
2211 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2212 // primitive types always pass
2213 if (t != T_OBJECT) {
2214 return true;
2215 } else {
2216 constraint_name = fd.object_key();
2217 }
2218 }
2219
2220 Dictionary* dictionary1 = loader_data1->dictionary();
2221 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2222
2223 Dictionary* dictionary2 = loader_data2->dictionary();
2224 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2225
2226 {
2227 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2228 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2229 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2230 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2231 klass2, class_loader2);
2232 }
2233 }
2234
2235 // Add entry to resolution error table to record the error when the first
2236 // attempt to resolve a reference to a class has failed.
2237 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2238 Symbol* error, Symbol* message) {
2239 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2240 int index = resolution_errors()->hash_to_index(hash);
2241 {
2242 MutexLocker ml(SystemDictionary_lock, Thread::current());
2243 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2244 }
2245 }
2246
2247 // Delete a resolution error for RedefineClasses for a constant pool is going away
2248 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2249 resolution_errors()->delete_entry(pool);
2250 }
2251
2252 // Lookup resolution error table. Returns error if found, otherwise NULL.
2253 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2254 Symbol** message) {
2255 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2256 int index = resolution_errors()->hash_to_index(hash);
2257 {
2258 MutexLocker ml(SystemDictionary_lock, Thread::current());
2259 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2260 if (entry != NULL) {
2261 *message = entry->message();
2262 return entry->error();
2263 } else {
2264 return NULL;
2265 }
2266 }
2267 }
2268
2269
2270 // Signature constraints ensure that callers and callees agree about
2271 // the meaning of type names in their signatures. This routine is the
2272 // intake for constraints. It collects them from several places:
2273 //
2274 // * LinkResolver::resolve_method (if check_access is true) requires
2275 // that the resolving class (the caller) and the defining class of
2276 // the resolved method (the callee) agree on each type in the
2277 // method's signature.
2278 //
2279 // * LinkResolver::resolve_interface_method performs exactly the same
2280 // checks.
2281 //
2282 // * LinkResolver::resolve_field requires that the constant pool
2283 // attempting to link to a field agree with the field's defining
2284 // class about the type of the field signature.
2285 //
2286 // * klassVtable::initialize_vtable requires that, when a class
2287 // overrides a vtable entry allocated by a superclass, that the
2288 // overriding method (i.e., the callee) agree with the superclass
2289 // on each type in the method's signature.
2290 //
2291 // * klassItable::initialize_itable requires that, when a class fills
2292 // in its itables, for each non-abstract method installed in an
2293 // itable, the method (i.e., the callee) agree with the interface
2294 // on each type in the method's signature.
2295 //
2296 // All those methods have a boolean (check_access, checkconstraints)
2297 // which turns off the checks. This is used from specialized contexts
2298 // such as bootstrapping, dumping, and debugging.
2299 //
2300 // No direct constraint is placed between the class and its
2301 // supertypes. Constraints are only placed along linked relations
2302 // between callers and callees. When a method overrides or implements
2303 // an abstract method in a supertype (superclass or interface), the
2304 // constraints are placed as if the supertype were the caller to the
2305 // overriding method. (This works well, since callers to the
2306 // supertype have already established agreement between themselves and
2307 // the supertype.) As a result of all this, a class can disagree with
2308 // its supertype about the meaning of a type name, as long as that
2309 // class neither calls a relevant method of the supertype, nor is
2310 // called (perhaps via an override) from the supertype.
2311 //
2312 //
2313 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2314 //
2315 // Make sure all class components (including arrays) in the given
2316 // signature will be resolved to the same class in both loaders.
2317 // Returns the name of the type that failed a loader constraint check, or
2318 // NULL if no constraint failed. No exception except OOME is thrown.
2319 // Arrays are not added to the loader constraint table, their elements are.
2320 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2321 Handle loader1, Handle loader2,
2322 bool is_method, TRAPS) {
2323 // Nothing to do if loaders are the same.
2324 if (loader1() == loader2()) {
2325 return NULL;
2326 }
2327
2328 SignatureStream sig_strm(signature, is_method);
2329 while (!sig_strm.is_done()) {
2330 if (sig_strm.is_object()) {
2331 Symbol* sig = sig_strm.as_symbol();
2332 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2333 return sig;
2334 }
2335 }
2336 sig_strm.next();
2337 }
2338 return NULL;
2339 }
2340
2341
2342 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2343 Symbol* signature,
2344 TRAPS) {
2345 methodHandle empty;
2346 assert(MethodHandles::is_signature_polymorphic(iid) &&
2347 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2348 iid != vmIntrinsics::_invokeGeneric,
2349 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2350
2351 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2352 int index = invoke_method_table()->hash_to_index(hash);
2353 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2354 methodHandle m;
2355 if (spe == NULL || spe->method() == NULL) {
2356 spe = NULL;
2357 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2358 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2359 if (!Arguments::is_interpreter_only()) {
2360 // Generate a compiled form of the MH intrinsic.
2361 AdapterHandlerLibrary::create_native_wrapper(m);
2362 // Check if have the compiled code.
2363 if (!m->has_compiled_code()) {
2364 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2365 "Out of space in CodeCache for method handle intrinsic");
2366 }
2367 }
2368 // Now grab the lock. We might have to throw away the new method,
2369 // if a racing thread has managed to install one at the same time.
2370 {
2371 MutexLocker ml(SystemDictionary_lock, THREAD);
2372 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2373 if (spe == NULL)
2374 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2375 if (spe->method() == NULL)
2376 spe->set_method(m());
2377 }
2378 }
2379
2380 assert(spe != NULL && spe->method() != NULL, "");
2381 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2382 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2383 "MH intrinsic invariant");
2384 return spe->method();
2385 }
2386
2387 // Helper for unpacking the return value from linkMethod and linkCallSite.
2388 static Method* unpack_method_and_appendix(Handle mname,
2389 Klass* accessing_klass,
2390 objArrayHandle appendix_box,
2391 Handle* appendix_result,
2392 TRAPS) {
2393 if (mname.not_null()) {
2394 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2395 if (m != NULL) {
2396 oop appendix = appendix_box->obj_at(0);
2397 if (TraceMethodHandles) {
2398 #ifndef PRODUCT
2399 ttyLocker ttyl;
2400 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2401 m->print();
2402 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2403 tty->cr();
2404 #endif //PRODUCT
2405 }
2406 (*appendix_result) = Handle(THREAD, appendix);
2407 // the target is stored in the cpCache and if a reference to this
2408 // MemberName is dropped we need a way to make sure the
2409 // class_loader containing this method is kept alive.
2410 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2411 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2412 this_key->record_dependency(m->method_holder());
2413 return mh();
2414 }
2415 }
2416 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2417 }
2418
2419 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2420 Symbol* name,
2421 Symbol* signature,
2422 Klass* accessing_klass,
2423 Handle *appendix_result,
2424 TRAPS) {
2425 assert(THREAD->can_call_java() ,"");
2426 Handle method_type =
2427 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2428
2429 int ref_kind = JVM_REF_invokeVirtual;
2430 oop name_oop = StringTable::intern(name, CHECK_NULL);
2431 Handle name_str (THREAD, name_oop);
2432 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2433 assert(appendix_box->obj_at(0) == NULL, "");
2434
2435 // This should not happen. JDK code should take care of that.
2436 if (accessing_klass == NULL || method_type.is_null()) {
2437 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2438 }
2439
2440 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2441 JavaCallArguments args;
2442 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2443 args.push_int(ref_kind);
2444 args.push_oop(Handle(THREAD, klass->java_mirror()));
2445 args.push_oop(name_str);
2446 args.push_oop(method_type);
2447 args.push_oop(appendix_box);
2448 JavaValue result(T_OBJECT);
2449 JavaCalls::call_static(&result,
2450 SystemDictionary::MethodHandleNatives_klass(),
2451 vmSymbols::linkMethod_name(),
2452 vmSymbols::linkMethod_signature(),
2453 &args, CHECK_NULL);
2454 Handle mname(THREAD, (oop) result.get_jobject());
2455 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2456 }
2457
2458 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2459 // We must ensure that all class loaders everywhere will reach this class, for any client.
2460 // This is a safe bet for public classes in java.lang, such as Object and String.
2461 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2462 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2463 static bool is_always_visible_class(oop mirror) {
2464 Klass* klass = java_lang_Class::as_Klass(mirror);
2465 if (klass->is_objArray_klass()) {
2466 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2467 }
2468 if (klass->is_typeArray_klass()) {
2469 return true; // primitive array
2470 }
2471 assert(klass->is_instance_klass(), "%s", klass->external_name());
2472 return klass->is_public() &&
2473 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2474 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2475 }
2476
2477
2478 // Return the Java mirror (java.lang.Class instance) for a single-character
2479 // descriptor. This result, when available, is the same as produced by the
2480 // heavier API point of the same name that takes a Symbol.
2481 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2482 return java_lang_Class::primitive_mirror(char2type(signature_char));
2483 }
2484
2485 // Find or construct the Java mirror (java.lang.Class instance) for a
2486 // for the given field type signature, as interpreted relative to the
2487 // given class loader. Handles primitives, void, references, arrays,
2488 // and all other reflectable types, except method types.
2489 // N.B. Code in reflection should use this entry point.
2490 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2491 Klass* accessing_klass,
2492 Handle class_loader,
2493 Handle protection_domain,
2494 SignatureStream::FailureMode failure_mode,
2495 TRAPS) {
2496 Handle empty;
2497
2498 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2499 "one or the other, or perhaps neither");
2500
2501 Symbol* type = signature;
2502
2503 // What we have here must be a valid field descriptor,
2504 // and all valid field descriptors are supported.
2505 // Produce the same java.lang.Class that reflection reports.
2506 if (type->utf8_length() == 1) {
2507
2508 // It's a primitive. (Void has a primitive mirror too.)
2509 char ch = type->char_at(0);
2510 assert(is_java_primitive(char2type(ch)) || ch == JVM_SIGNATURE_VOID, "");
2511 return Handle(THREAD, find_java_mirror_for_type(ch));
2512
2513 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2514
2515 // It's a reference type.
2516 if (accessing_klass != NULL) {
2517 class_loader = Handle(THREAD, accessing_klass->class_loader());
2518 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2519 }
2520 Klass* constant_type_klass;
2521 if (failure_mode == SignatureStream::ReturnNull) {
2522 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2523 CHECK_(empty));
2524 } else {
2525 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2526 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2527 throw_error, CHECK_(empty));
2528 }
2529 if (constant_type_klass == NULL) {
2530 return Handle(); // report failure this way
2531 }
2532 Handle mirror(THREAD, constant_type_klass->java_mirror());
2533
2534 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2535 if (accessing_klass != NULL) {
2536 Klass* sel_klass = constant_type_klass;
2537 bool fold_type_to_class = true;
2538 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2539 fold_type_to_class, CHECK_(empty));
2540 }
2541
2542 return mirror;
2543
2544 }
2545
2546 // Fall through to an error.
2547 assert(false, "unsupported mirror syntax");
2548 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2549 }
2550
2551
2552 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2553 // signature, as interpreted relative to the given class loader.
2554 // Because of class loader constraints, all method handle usage must be
2555 // consistent with this loader.
2556 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2557 Klass* accessing_klass,
2558 TRAPS) {
2559 Handle empty;
2560 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2561 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2562 int index = invoke_method_table()->hash_to_index(hash);
2563 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2564 if (spe != NULL && spe->method_type() != NULL) {
2565 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2566 return Handle(THREAD, spe->method_type());
2567 } else if (!THREAD->can_call_java()) {
2568 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2569 return Handle(); // do not attempt from within compiler, unless it was cached
2570 }
2571
2572 Handle class_loader, protection_domain;
2573 if (accessing_klass != NULL) {
2574 class_loader = Handle(THREAD, accessing_klass->class_loader());
2575 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2576 }
2577 bool can_be_cached = true;
2578 int npts = ArgumentCount(signature).size();
2579 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2580 int arg = 0;
2581 Handle rt; // the return type from the signature
2582 ResourceMark rm(THREAD);
2583 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2584 oop mirror = NULL;
2585 if (can_be_cached) {
2586 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2587 mirror = ss.as_java_mirror(Handle(), Handle(),
2588 SignatureStream::ReturnNull, CHECK_(empty));
2589 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2590 // Fall back to accessing_klass context.
2591 can_be_cached = false;
2592 }
2593 }
2594 if (!can_be_cached) {
2595 // Resolve, throwing a real error if it doesn't work.
2596 mirror = ss.as_java_mirror(class_loader, protection_domain,
2597 SignatureStream::NCDFError, CHECK_(empty));
2598 }
2599 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2600 if (ss.at_return_type())
2601 rt = Handle(THREAD, mirror);
2602 else
2603 pts->obj_at_put(arg++, mirror);
2604
2605 // Check accessibility.
2606 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2607 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2608 mirror = NULL; // safety
2609 // Emulate ConstantPool::verify_constant_pool_resolve.
2610 bool fold_type_to_class = true;
2611 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2612 fold_type_to_class, CHECK_(empty));
2613 }
2614 }
2615 assert(arg == npts, "");
2616
2617 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2618 JavaCallArguments args(Handle(THREAD, rt()));
2619 args.push_oop(pts);
2620 JavaValue result(T_OBJECT);
2621 JavaCalls::call_static(&result,
2622 SystemDictionary::MethodHandleNatives_klass(),
2623 vmSymbols::findMethodHandleType_name(),
2624 vmSymbols::findMethodHandleType_signature(),
2625 &args, CHECK_(empty));
2626 Handle method_type(THREAD, (oop) result.get_jobject());
2627
2628 if (can_be_cached) {
2629 // We can cache this MethodType inside the JVM.
2630 MutexLocker ml(SystemDictionary_lock, THREAD);
2631 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2632 if (spe == NULL)
2633 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2634 if (spe->method_type() == NULL) {
2635 spe->set_method_type(method_type());
2636 }
2637 }
2638
2639 // report back to the caller with the MethodType
2640 return method_type;
2641 }
2642
2643 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2644 Klass* accessing_klass,
2645 TRAPS) {
2646 Handle empty;
2647 ResourceMark rm(THREAD);
2648 SignatureStream ss(signature, /*is_method=*/ false);
2649 if (!ss.is_done()) {
2650 Handle class_loader, protection_domain;
2651 if (accessing_klass != NULL) {
2652 class_loader = Handle(THREAD, accessing_klass->class_loader());
2653 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2654 }
2655 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2656 ss.next();
2657 if (ss.is_done()) {
2658 return Handle(THREAD, mirror);
2659 }
2660 }
2661 return empty;
2662 }
2663
2664 // Ask Java code to find or construct a method handle constant.
2665 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2666 int ref_kind, //e.g., JVM_REF_invokeVirtual
2667 Klass* callee,
2668 Symbol* name,
2669 Symbol* signature,
2670 TRAPS) {
2671 Handle empty;
2672 if (caller == NULL) {
2673 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2674 }
2675 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2676 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2677
2678 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2679 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2680 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2681 java_lang_invoke_MemberName::set_name (mname(), name_str());
2682 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2683 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2684
2685 if (ref_kind == JVM_REF_invokeVirtual &&
2686 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2687 // Skip resolution for public signature polymorphic methods such as
2688 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2689 // They require appendix argument which MemberName resolution doesn't handle.
2690 // There's special logic on JDK side to handle them
2691 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2692 } else {
2693 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2694 }
2695
2696 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2697 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2698
2699 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2700 JavaCallArguments args;
2701 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2702 args.push_int(ref_kind);
2703 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2704 args.push_oop(name_str);
2705 args.push_oop(type);
2706 JavaValue result(T_OBJECT);
2707 JavaCalls::call_static(&result,
2708 SystemDictionary::MethodHandleNatives_klass(),
2709 vmSymbols::linkMethodHandleConstant_name(),
2710 vmSymbols::linkMethodHandleConstant_signature(),
2711 &args, CHECK_(empty));
2712 return Handle(THREAD, (oop) result.get_jobject());
2713 }
2714
2715 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2716 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2717 // with linkage results being stored back into the bootstrap specifier.
2718 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2719 // Resolve the bootstrap specifier, its name, type, and static arguments
2720 bootstrap_specifier.resolve_bsm(CHECK);
2721
2722 // This should not happen. JDK code should take care of that.
2723 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2724 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2725 }
2726
2727 bool is_indy = bootstrap_specifier.is_method_call();
2728 objArrayHandle appendix_box;
2729 if (is_indy) {
2730 // Some method calls may require an appendix argument. Arrange to receive it.
2731 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2732 assert(appendix_box->obj_at(0) == NULL, "");
2733 }
2734
2735 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2736 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2737 JavaCallArguments args;
2738 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2739 args.push_int(bootstrap_specifier.bss_index());
2740 args.push_oop(bootstrap_specifier.bsm());
2741 args.push_oop(bootstrap_specifier.name_arg());
2742 args.push_oop(bootstrap_specifier.type_arg());
2743 args.push_oop(bootstrap_specifier.arg_values());
2744 if (is_indy) {
2745 args.push_oop(appendix_box);
2746 }
2747 JavaValue result(T_OBJECT);
2748 JavaCalls::call_static(&result,
2749 SystemDictionary::MethodHandleNatives_klass(),
2750 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2751 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2752 &args, CHECK);
2753
2754 Handle value(THREAD, (oop) result.get_jobject());
2755 if (is_indy) {
2756 Handle appendix;
2757 Method* method = unpack_method_and_appendix(value,
2758 bootstrap_specifier.caller(),
2759 appendix_box,
2760 &appendix, CHECK);
2761 methodHandle mh(THREAD, method);
2762 bootstrap_specifier.set_resolved_method(mh, appendix);
2763 } else {
2764 bootstrap_specifier.set_resolved_value(value);
2765 }
2766
2767 // sanity check
2768 assert(bootstrap_specifier.is_resolved() ||
2769 (bootstrap_specifier.is_method_call() &&
2770 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2771 }
2772
2773 // Protection domain cache table handling
2774
2775 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2776 return _pd_cache_table->get(protection_domain);
2777 }
2778
2779 // ----------------------------------------------------------------------------
2780
2781 void SystemDictionary::print_on(outputStream *st) {
2782 CDS_ONLY(SystemDictionaryShared::print_on(st));
2783 GCMutexLocker mu(SystemDictionary_lock);
2784
2785 ClassLoaderDataGraph::print_dictionary(st);
2786
2787 // Placeholders
2788 placeholders()->print_on(st);
2789 st->cr();
2790
2791 // loader constraints - print under SD_lock
2792 constraints()->print_on(st);
2793 st->cr();
2794
2795 _pd_cache_table->print_on(st);
2796 st->cr();
2797 }
2798
2799 void SystemDictionary::print() { print_on(tty); }
2800
2801 void SystemDictionary::verify() {
2802 guarantee(constraints() != NULL,
2803 "Verify of loader constraints failed");
2804 guarantee(placeholders()->number_of_entries() >= 0,
2805 "Verify of placeholders failed");
2806
2807 GCMutexLocker mu(SystemDictionary_lock);
2808
2809 // Verify dictionary
2810 ClassLoaderDataGraph::verify_dictionary();
2811
2812 placeholders()->verify();
2813
2814 // Verify constraint table
2815 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2816 constraints()->verify(placeholders());
2817
2818 _pd_cache_table->verify();
2819 }
2820
2821 void SystemDictionary::dump(outputStream *st, bool verbose) {
2822 assert_locked_or_safepoint(SystemDictionary_lock);
2823 if (verbose) {
2824 print_on(st);
2825 } else {
2826 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2827 ClassLoaderDataGraph::print_table_statistics(st);
2828 placeholders()->print_table_statistics(st, "Placeholder Table");
2829 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2830 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2831 }
2832 }
2833
2834 TableStatistics SystemDictionary::placeholders_statistics() {
2835 MutexLocker ml(SystemDictionary_lock);
2836 return placeholders()->statistics_calculate();
2837 }
2838
2839 TableStatistics SystemDictionary::loader_constraints_statistics() {
2840 MutexLocker ml(SystemDictionary_lock);
2841 return constraints()->statistics_calculate();
2842 }
2843
2844 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2845 MutexLocker ml(SystemDictionary_lock);
2846 return pd_cache_table()->statistics_calculate();
2847 }
2848
2849 // Utility for dumping dictionaries.
2850 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2851 DCmdWithParser(output, heap),
2852 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2853 "BOOLEAN", false, "false") {
2854 _dcmdparser.add_dcmd_option(&_verbose);
2855 }
2856
2857 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2858 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2859 _verbose.value());
2860 VMThread::execute(&dumper);
2861 }
2862
2863 int SystemDictionaryDCmd::num_arguments() {
2864 ResourceMark rm;
2865 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2866 if (dcmd != NULL) {
2867 DCmdMark mark(dcmd);
2868 return dcmd->_dcmdparser.num_arguments();
2869 } else {
2870 return 0;
2871 }
2872 }