1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/symbolTable.hpp"
44 #include "classfile/systemDictionary.hpp"
45 #include "classfile/vmSymbols.hpp"
46 #include "code/codeCache.hpp"
47 #include "compiler/compileBroker.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/oopStorage.inline.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "interpreter/bytecodeStream.hpp"
52 #include "interpreter/interpreter.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "logging/log.hpp"
55 #include "logging/logStream.hpp"
56 #include "memory/filemap.hpp"
57 #include "memory/heapShared.hpp"
58 #include "memory/metaspaceClosure.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/access.inline.hpp"
63 #include "oops/instanceKlass.hpp"
64 #include "oops/instanceRefKlass.hpp"
65 #include "oops/klass.inline.hpp"
66 #include "oops/method.inline.hpp"
67 #include "oops/methodData.hpp"
68 #include "oops/objArrayKlass.hpp"
69 #include "oops/objArrayOop.inline.hpp"
70 #include "oops/oop.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #if INCLUDE_CDS
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JFR
91 #include "jfr/jfr.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108 oop SystemDictionary::_java_platform_loader = NULL;
109
110 // Default ProtectionDomainCacheSize value
111
112 const int defaultProtectionDomainCacheSize = 1009;
113
114 // ----------------------------------------------------------------------------
115 // Java-level SystemLoader and PlatformLoader
116
117 oop SystemDictionary::java_system_loader() {
118 return _java_system_loader;
119 }
120
121 oop SystemDictionary::java_platform_loader() {
122 return _java_platform_loader;
123 }
124
125 void SystemDictionary::compute_java_loaders(TRAPS) {
126 JavaValue result(T_OBJECT);
127 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
128 JavaCalls::call_static(&result,
129 class_loader_klass,
130 vmSymbols::getSystemClassLoader_name(),
131 vmSymbols::void_classloader_signature(),
132 CHECK);
133
134 _java_system_loader = (oop)result.get_jobject();
135
136 JavaCalls::call_static(&result,
137 class_loader_klass,
138 vmSymbols::getPlatformClassLoader_name(),
139 vmSymbols::void_classloader_signature(),
140 CHECK);
141
142 _java_platform_loader = (oop)result.get_jobject();
143 }
144
145 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
146 if (class_loader.is_null()) return ClassLoaderData::the_null_class_loader_data();
147 return ClassLoaderDataGraph::find_or_create(class_loader);
148 }
149
150 // ----------------------------------------------------------------------------
151 // Parallel class loading check
152
153 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
154 if (class_loader.is_null()) return true;
155 if (AlwaysLockClassLoader) return false;
156 return java_lang_ClassLoader::parallelCapable(class_loader());
157 }
158 // ----------------------------------------------------------------------------
159 // ParallelDefineClass flag does not apply to bootclass loader
160 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
161 if (class_loader.is_null()) return false;
162 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
163 return true;
164 }
165 return false;
166 }
167
168 // Returns true if the passed class loader is the builtin application class loader
169 // or a custom system class loader. A customer system class loader can be
170 // specified via -Djava.system.class.loader.
171 bool SystemDictionary::is_system_class_loader(oop class_loader) {
172 if (class_loader == NULL) {
173 return false;
174 }
175 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
176 class_loader == _java_system_loader);
177 }
178
179 // Returns true if the passed class loader is the platform class loader.
180 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
185 }
186
187 // ----------------------------------------------------------------------------
188 // Resolving of classes
189
190 // Forwards to resolve_or_null
191
192 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
193 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
194 if (HAS_PENDING_EXCEPTION || klass == NULL) {
195 // can return a null klass
196 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
197 }
198 return klass;
199 }
200
201 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
202 bool throw_error,
203 Klass* klass, TRAPS) {
204 if (HAS_PENDING_EXCEPTION) {
205 // If we have a pending exception we forward it to the caller, unless throw_error is true,
206 // in which case we have to check whether the pending exception is a ClassNotFoundException,
207 // and if so convert it to a NoClassDefFoundError
208 // And chain the original ClassNotFoundException
209 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
210 ResourceMark rm(THREAD);
211 assert(klass == NULL, "Should not have result with exception pending");
212 Handle e(THREAD, PENDING_EXCEPTION);
213 CLEAR_PENDING_EXCEPTION;
214 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
215 } else {
216 return NULL;
217 }
218 }
219 // Class not found, throw appropriate error or exception depending on value of throw_error
220 if (klass == NULL) {
221 ResourceMark rm(THREAD);
222 if (throw_error) {
223 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
224 } else {
225 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
226 }
227 }
228 return klass;
229 }
230
231
232 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
233 bool throw_error, TRAPS)
234 {
235 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
236 }
237
238
239 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
240
241 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
242 if (Signature::is_array(class_name)) {
243 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
244 } else {
245 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
246 }
247 }
248
249 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
250 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
251 Handle class_loader,
252 Handle protection_domain,
253 TRAPS) {
254 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
255 if (Signature::has_envelope(class_name)) {
256 ResourceMark rm(THREAD);
257 // Ignore wrapping L and ;.
258 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
259 class_name->utf8_length() - 2);
260 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
261 } else {
262 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
263 }
264 }
265
266 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
267 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
268 }
269
270 // Forwards to resolve_instance_class_or_null
271
272 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
273 Handle class_loader,
274 Handle protection_domain,
275 TRAPS) {
276 assert(Signature::is_array(class_name), "must be array");
277 ResourceMark rm(THREAD);
278 SignatureStream ss(class_name, false);
279 int ndims = ss.skip_array_prefix(); // skip all '['s
280 Klass* k = NULL;
281 BasicType t = ss.type();
282 if (ss.has_envelope()) {
283 Symbol* obj_class = ss.as_symbol();
284 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
285 class_loader,
286 protection_domain,
287 CHECK_NULL);
288 if (k != NULL) {
289 k = k->array_klass(ndims, CHECK_NULL);
290 }
291 } else {
292 k = Universe::typeArrayKlassObj(t);
293 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
294 }
295 return k;
296 }
297
298
299 // Must be called for any super-class or super-interface resolution
300 // during class definition to allow class circularity checking
301 // super-interface callers:
302 // parse_interfaces - for defineClass & jvmtiRedefineClasses
303 // super-class callers:
304 // ClassFileParser - for defineClass & jvmtiRedefineClasses
305 // load_shared_class - while loading a class from shared archive
306 // resolve_instance_class_or_null:
307 // via: handle_parallel_super_load
308 // when resolving a class that has an existing placeholder with
309 // a saved superclass [i.e. a defineClass is currently in progress]
310 // if another thread is trying to resolve the class, it must do
311 // super-class checks on its own thread to catch class circularity
312 // This last call is critical in class circularity checking for cases
313 // where classloading is delegated to different threads and the
314 // classloader lock is released.
315 // Take the case: Base->Super->Base
316 // 1. If thread T1 tries to do a defineClass of class Base
317 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
318 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
319 // so it tries to load Super
320 // 3. If we load the class internally, or user classloader uses same thread
321 // loadClassFromxxx or defineClass via parseClassFile Super ...
322 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
323 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
324 // 3.4 calls resolve_super_or_fail Base
325 // 3.5 finds T1,Base -> throws class circularity
326 //OR 4. If T2 tries to resolve Super via defineClass Super ...
327 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
328 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
329 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
330 // 4.4 finds T2, Super -> throws class circularity
331 // Must be called, even if superclass is null, since this is
332 // where the placeholder entry is created which claims this
333 // thread is loading this class/classloader.
334 // Be careful when modifying this code: once you have run
335 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
336 // you need to find_and_remove it before returning.
337 // So be careful to not exit with a CHECK_ macro betweeen these calls.
338 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
339 Symbol* super_name,
340 Handle class_loader,
341 Handle protection_domain,
342 bool is_superclass,
343 TRAPS) {
344 assert(!Signature::is_array(super_name), "invalid super class name");
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for handling UNREGISTERED shared classes.
348 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(THREAD, SystemDictionary_lock);
381 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
382 InstanceKlass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if super_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->java_super()) != NULL) &&
391 ((quicksuperk->name() == super_name) &&
392 (quicksuperk->class_loader() == class_loader()))) {
393 return quicksuperk;
394 } else {
395 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
396 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
397 throw_circularity_error = true;
398 }
399 }
400 if (!throw_circularity_error) {
401 // Be careful not to exit resolve_super
402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
403 }
404 }
405 if (throw_circularity_error) {
406 ResourceMark rm(THREAD);
407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
408 }
409
410 // java.lang.Object should have been found above
411 assert(super_name != NULL, "null super class for resolving");
412 // Resolve the super class or interface, check results on return
413 InstanceKlass* superk =
414 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(THREAD, SystemDictionary_lock);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
433 assert(k == NULL || k == superk, "must be");
434 if (k == NULL) {
435 superk = NULL;
436 }
437 }
438
439 return superk;
440 }
441
442 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
443 Handle class_loader,
444 Handle protection_domain,
445 TRAPS) {
446 // Now we have to call back to java to check if the initating class has access
447 JavaValue result(T_VOID);
448 LogTarget(Debug, protectiondomain) lt;
449 if (lt.is_enabled()) {
450 ResourceMark rm(THREAD);
451 // Print out trace information
452 LogStream ls(lt);
453 ls.print_cr("Checking package access");
454 if (class_loader() != NULL) {
455 ls.print("class loader: ");
456 class_loader()->print_value_on(&ls);
457 } else {
458 ls.print_cr("class loader: NULL");
459 }
460 if (protection_domain() != NULL) {
461 ls.print(" protection domain: ");
462 protection_domain()->print_value_on(&ls);
463 } else {
464 ls.print_cr(" protection domain: NULL");
465 }
466 ls.print(" loading: "); klass->print_value_on(&ls);
467 ls.cr();
468 }
469
470 // This handle and the class_loader handle passed in keeps this class from
471 // being unloaded through several GC points.
472 // The class_loader handle passed in is the initiating loader.
473 Handle mirror(THREAD, klass->java_mirror());
474
475 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
476 JavaCalls::call_special(&result,
477 class_loader,
478 system_loader,
479 vmSymbols::checkPackageAccess_name(),
480 vmSymbols::class_protectiondomain_signature(),
481 mirror,
482 protection_domain,
483 THREAD);
484
485 if (HAS_PENDING_EXCEPTION) {
486 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
487 } else {
488 log_debug(protectiondomain)("granted");
489 }
490
491 if (HAS_PENDING_EXCEPTION) return;
492
493 // If no exception has been thrown, we have validated the protection domain
494 // Insert the protection domain of the initiating class into the set.
495 {
496 ClassLoaderData* loader_data = class_loader_data(class_loader);
497 Dictionary* dictionary = loader_data->dictionary();
498
499 Symbol* kn = klass->name();
500 unsigned int d_hash = dictionary->compute_hash(kn);
501
502 MutexLocker mu(THREAD, SystemDictionary_lock);
503 int d_index = dictionary->hash_to_index(d_hash);
504 dictionary->add_protection_domain(d_index, d_hash, klass,
505 protection_domain, THREAD);
506 }
507 }
508
509 // We only get here if this thread finds that another thread
510 // has already claimed the placeholder token for the current operation,
511 // but that other thread either never owned or gave up the
512 // object lock
513 // Waits on SystemDictionary_lock to indicate placeholder table updated
514 // On return, caller must recheck placeholder table state
515 //
516 // We only get here if
517 // 1) custom classLoader, i.e. not bootstrap classloader
518 // 2) custom classLoader has broken the class loader objectLock
519 // so another thread got here in parallel
520 //
521 // lockObject must be held.
522 // Complicated dance due to lock ordering:
523 // Must first release the classloader object lock to
524 // allow initial definer to complete the class definition
525 // and to avoid deadlock
526 // Reclaim classloader lock object with same original recursion count
527 // Must release SystemDictionary_lock after notify, since
528 // class loader lock must be claimed before SystemDictionary_lock
529 // to prevent deadlocks
530 //
531 // The notify allows applications that did an untimed wait() on
532 // the classloader object lock to not hang.
533 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
534 assert_lock_strong(SystemDictionary_lock);
535
536 bool calledholdinglock
537 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
538 assert(calledholdinglock,"must hold lock for notify");
539 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
540 ObjectSynchronizer::notifyall(lockObject, THREAD);
541 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
542 SystemDictionary_lock->wait();
543 SystemDictionary_lock->unlock();
544 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
545 SystemDictionary_lock->lock();
546 }
547
548 // If the class in is in the placeholder table, class loading is in progress
549 // For cases where the application changes threads to load classes, it
550 // is critical to ClassCircularity detection that we try loading
551 // the superclass on the same thread internally, so we do parallel
552 // super class loading here.
553 // This also is critical in cases where the original thread gets stalled
554 // even in non-circularity situations.
555 // Note: must call resolve_super_or_fail even if null super -
556 // to force placeholder entry creation for this class for circularity detection
557 // Caller must check for pending exception
558 // Returns non-null Klass* if other thread has completed load
559 // and we are done,
560 // If return null Klass* and no pending exception, the caller must load the class
561 InstanceKlass* SystemDictionary::handle_parallel_super_load(
562 Symbol* name, Symbol* superclassname, Handle class_loader,
563 Handle protection_domain, Handle lockObject, TRAPS) {
564
565 ClassLoaderData* loader_data = class_loader_data(class_loader);
566 Dictionary* dictionary = loader_data->dictionary();
567 unsigned int d_hash = dictionary->compute_hash(name);
568 unsigned int p_hash = placeholders()->compute_hash(name);
569 int p_index = placeholders()->hash_to_index(p_hash);
570
571 // superk is not used, resolve_super called for circularity check only
572 // This code is reached in two situations. One if this thread
573 // is loading the same class twice (e.g. ClassCircularity, or
574 // java.lang.instrument).
575 // The second is if another thread started the resolve_super first
576 // and has not yet finished.
577 // In both cases the original caller will clean up the placeholder
578 // entry on error.
579 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
580 superclassname,
581 class_loader,
582 protection_domain,
583 true,
584 CHECK_NULL);
585
586 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
587 // Serial class loaders and bootstrap classloader do wait for superclass loads
588 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
589 MutexLocker mu(THREAD, SystemDictionary_lock);
590 // Check if classloading completed while we were loading superclass or waiting
591 return find_class(d_hash, name, dictionary);
592 }
593
594 // must loop to both handle other placeholder updates
595 // and spurious notifications
596 bool super_load_in_progress = true;
597 PlaceholderEntry* placeholder;
598 while (super_load_in_progress) {
599 MutexLocker mu(THREAD, SystemDictionary_lock);
600 // Check if classloading completed while we were loading superclass or waiting
601 InstanceKlass* check = find_class(d_hash, name, dictionary);
602 if (check != NULL) {
603 // Klass is already loaded, so just return it
604 return check;
605 } else {
606 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
607 if (placeholder && placeholder->super_load_in_progress() ){
608 // We only get here if the application has released the
609 // classloader lock when another thread was in the middle of loading a
610 // superclass/superinterface for this class, and now
611 // this thread is also trying to load this class.
612 // To minimize surprises, the first thread that started to
613 // load a class should be the one to complete the loading
614 // with the classfile it initially expected.
615 // This logic has the current thread wait once it has done
616 // all the superclass/superinterface loading it can, until
617 // the original thread completes the class loading or fails
618 // If it completes we will use the resulting InstanceKlass
619 // which we will find below in the systemDictionary.
620 // We also get here for parallel bootstrap classloader
621 if (class_loader.is_null()) {
622 SystemDictionary_lock->wait();
623 } else {
624 double_lock_wait(lockObject, THREAD);
625 }
626 } else {
627 // If not in SD and not in PH, other thread's load must have failed
628 super_load_in_progress = false;
629 }
630 }
631 }
632 return NULL;
633 }
634
635 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
636 assert(event != NULL, "invariant");
637 assert(k != NULL, "invariant");
638 assert(event->should_commit(), "invariant");
639 event->set_loadedClass(k);
640 event->set_definingClassLoader(k->class_loader_data());
641 event->set_initiatingClassLoader(init_cld);
642 event->commit();
643 }
644
645
646 // Be careful when modifying this code: once you have run
647 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
648 // you need to find_and_remove it before returning.
649 // So be careful to not exit with a CHECK_ macro betweeen these calls.
650 //
651 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
652 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
653 Handle class_loader,
654 Handle protection_domain,
655 TRAPS) {
656 assert(name != NULL && !Signature::is_array(name) &&
657 !Signature::has_envelope(name), "invalid class name");
658
659 EventClassLoad class_load_start_event;
660
661 HandleMark hm(THREAD);
662
663 // Fix for 4474172; see evaluation for more details
664 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
665 ClassLoaderData* loader_data = register_loader(class_loader);
666 Dictionary* dictionary = loader_data->dictionary();
667 unsigned int d_hash = dictionary->compute_hash(name);
668
669 // Do lookup to see if class already exist and the protection domain
670 // has the right access
671 // This call uses find which checks protection domain already matches
672 // All subsequent calls use find_class, and set has_loaded_class so that
673 // before we return a result we call out to java to check for valid protection domain
674 // to allow returning the Klass* and add it to the pd_set if it is valid
675 {
676 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
677 if (probe != NULL) return probe;
678 }
679
680 // Non-bootstrap class loaders will call out to class loader and
681 // define via jvm/jni_DefineClass which will acquire the
682 // class loader object lock to protect against multiple threads
683 // defining the class in parallel by accident.
684 // This lock must be acquired here so the waiter will find
685 // any successful result in the SystemDictionary and not attempt
686 // the define.
687 // ParallelCapable Classloaders and the bootstrap classloader
688 // do not acquire lock here.
689 bool DoObjectLock = true;
690 if (is_parallelCapable(class_loader)) {
691 DoObjectLock = false;
692 }
693
694 unsigned int p_hash = placeholders()->compute_hash(name);
695 int p_index = placeholders()->hash_to_index(p_hash);
696
697 // Class is not in SystemDictionary so we have to do loading.
698 // Make sure we are synchronized on the class loader before we proceed
699 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
700 check_loader_lock_contention(lockObject, THREAD);
701 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
702
703 // Check again (after locking) if class already exist in SystemDictionary
704 bool class_has_been_loaded = false;
705 bool super_load_in_progress = false;
706 bool havesupername = false;
707 InstanceKlass* k = NULL;
708 PlaceholderEntry* placeholder;
709 Symbol* superclassname = NULL;
710
711 assert(THREAD->can_call_java(),
712 "can not load classes with compiler thread: class=%s, classloader=%s",
713 name->as_C_string(),
714 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
715 {
716 MutexLocker mu(THREAD, SystemDictionary_lock);
717 InstanceKlass* check = find_class(d_hash, name, dictionary);
718 if (check != NULL) {
719 // InstanceKlass is already loaded, so just return it
720 class_has_been_loaded = true;
721 k = check;
722 } else {
723 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (placeholder && placeholder->super_load_in_progress()) {
725 super_load_in_progress = true;
726 if (placeholder->havesupername() == true) {
727 superclassname = placeholder->supername();
728 havesupername = true;
729 }
730 }
731 }
732 }
733
734 // If the class is in the placeholder table, class loading is in progress
735 if (super_load_in_progress && havesupername==true) {
736 k = handle_parallel_super_load(name,
737 superclassname,
738 class_loader,
739 protection_domain,
740 lockObject, THREAD);
741 if (HAS_PENDING_EXCEPTION) {
742 return NULL;
743 }
744 if (k != NULL) {
745 class_has_been_loaded = true;
746 }
747 }
748
749 bool throw_circularity_error = false;
750 if (!class_has_been_loaded) {
751 bool load_instance_added = false;
752
753 // add placeholder entry to record loading instance class
754 // Five cases:
755 // All cases need to prevent modifying bootclasssearchpath
756 // in parallel with a classload of same classname
757 // Redefineclasses uses existence of the placeholder for the duration
758 // of the class load to prevent concurrent redefinition of not completely
759 // defined classes.
760 // case 1. traditional classloaders that rely on the classloader object lock
761 // - no other need for LOAD_INSTANCE
762 // case 2. traditional classloaders that break the classloader object lock
763 // as a deadlock workaround. Detection of this case requires that
764 // this check is done while holding the classloader object lock,
765 // and that lock is still held when calling classloader's loadClass.
766 // For these classloaders, we ensure that the first requestor
767 // completes the load and other requestors wait for completion.
768 // case 3. Bootstrap classloader - don't own objectLocker
769 // This classloader supports parallelism at the classloader level,
770 // but only allows a single load of a class/classloader pair.
771 // No performance benefit and no deadlock issues.
772 // case 4. parallelCapable user level classloaders - without objectLocker
773 // Allow parallel classloading of a class/classloader pair
774
775 {
776 MutexLocker mu(THREAD, SystemDictionary_lock);
777 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
778 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
779 if (oldprobe) {
780 // only need check_seen_thread once, not on each loop
781 // 6341374 java/lang/Instrument with -Xcomp
782 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
783 throw_circularity_error = true;
784 } else {
785 // case 1: traditional: should never see load_in_progress.
786 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
787
788 // case 3: bootstrap classloader: prevent futile classloading,
789 // wait on first requestor
790 if (class_loader.is_null()) {
791 SystemDictionary_lock->wait();
792 } else {
793 // case 2: traditional with broken classloader lock. wait on first
794 // requestor.
795 double_lock_wait(lockObject, THREAD);
796 }
797 // Check if classloading completed while we were waiting
798 InstanceKlass* check = find_class(d_hash, name, dictionary);
799 if (check != NULL) {
800 // Klass is already loaded, so just return it
801 k = check;
802 class_has_been_loaded = true;
803 }
804 // check if other thread failed to load and cleaned up
805 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
806 }
807 }
808 }
809 }
810 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
811 // case 4: parallelCapable: allow competing threads to try
812 // LOAD_INSTANCE in parallel
813
814 if (!throw_circularity_error && !class_has_been_loaded) {
815 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
816 load_instance_added = true;
817 // For class loaders that do not acquire the classloader object lock,
818 // if they did not catch another thread holding LOAD_INSTANCE,
819 // need a check analogous to the acquire ObjectLocker/find_class
820 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
821 // one final check if the load has already completed
822 // class loaders holding the ObjectLock shouldn't find the class here
823 InstanceKlass* check = find_class(d_hash, name, dictionary);
824 if (check != NULL) {
825 // Klass is already loaded, so return it after checking/adding protection domain
826 k = check;
827 class_has_been_loaded = true;
828 }
829 }
830 }
831
832 // must throw error outside of owning lock
833 if (throw_circularity_error) {
834 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
835 ResourceMark rm(THREAD);
836 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
837 }
838
839 if (!class_has_been_loaded) {
840
841 // Do actual loading
842 k = load_instance_class(name, class_loader, THREAD);
843
844 // If everything was OK (no exceptions, no null return value), and
845 // class_loader is NOT the defining loader, do a little more bookkeeping.
846 if (!HAS_PENDING_EXCEPTION && k != NULL &&
847 k->class_loader() != class_loader()) {
848
849 check_constraints(d_hash, k, class_loader, false, THREAD);
850
851 // Need to check for a PENDING_EXCEPTION again; check_constraints
852 // can throw but we may have to remove entry from the placeholder table below.
853 if (!HAS_PENDING_EXCEPTION) {
854 // Record dependency for non-parent delegation.
855 // This recording keeps the defining class loader of the klass (k) found
856 // from being unloaded while the initiating class loader is loaded
857 // even if the reference to the defining class loader is dropped
858 // before references to the initiating class loader.
859 loader_data->record_dependency(k);
860
861 { // Grabbing the Compile_lock prevents systemDictionary updates
862 // during compilations.
863 MutexLocker mu(THREAD, Compile_lock);
864 update_dictionary(d_hash, p_index, p_hash,
865 k, class_loader, THREAD);
866 }
867
868 if (JvmtiExport::should_post_class_load()) {
869 Thread *thread = THREAD;
870 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
871 JvmtiExport::post_class_load((JavaThread *) thread, k);
872 }
873 }
874 }
875 } // load_instance_class
876
877 if (load_instance_added == true) {
878 // clean up placeholder entries for LOAD_INSTANCE success or error
879 // This brackets the SystemDictionary updates for both defining
880 // and initiating loaders
881 MutexLocker mu(THREAD, SystemDictionary_lock);
882 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
883 SystemDictionary_lock->notify_all();
884 }
885 }
886
887 if (HAS_PENDING_EXCEPTION || k == NULL) {
888 return NULL;
889 }
890 if (class_load_start_event.should_commit()) {
891 post_class_load_event(&class_load_start_event, k, loader_data);
892 }
893 #ifdef ASSERT
894 {
895 ClassLoaderData* loader_data = k->class_loader_data();
896 MutexLocker mu(THREAD, SystemDictionary_lock);
897 InstanceKlass* kk = find_class(name, loader_data);
898 assert(kk == k, "should be present in dictionary");
899 }
900 #endif
901
902 // return if the protection domain in NULL
903 if (protection_domain() == NULL) return k;
904
905 // Check the protection domain has the right access
906 if (dictionary->is_valid_protection_domain(d_hash, name,
907 protection_domain)) {
908 return k;
909 }
910
911 // Verify protection domain. If it fails an exception is thrown
912 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
913
914 return k;
915 }
916
917
918 // This routine does not lock the system dictionary.
919 //
920 // Since readers don't hold a lock, we must make sure that system
921 // dictionary entries are only removed at a safepoint (when only one
922 // thread is running), and are added to in a safe way (all links must
923 // be updated in an MT-safe manner).
924 //
925 // Callers should be aware that an entry could be added just after
926 // _dictionary->bucket(index) is read here, so the caller will not see
927 // the new entry.
928
929 Klass* SystemDictionary::find(Symbol* class_name,
930 Handle class_loader,
931 Handle protection_domain,
932 TRAPS) {
933
934 // The result of this call should be consistent with the result
935 // of the call to resolve_instance_class_or_null().
936 // See evaluation 6790209 and 4474172 for more details.
937 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
938 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
939
940 if (loader_data == NULL) {
941 // If the ClassLoaderData has not been setup,
942 // then the class loader has no entries in the dictionary.
943 return NULL;
944 }
945
946 Dictionary* dictionary = loader_data->dictionary();
947 unsigned int d_hash = dictionary->compute_hash(class_name);
948 return dictionary->find(d_hash, class_name,
949 protection_domain);
950 }
951
952
953 // Look for a loaded instance or array klass by name. Do not do any loading.
954 // return NULL in case of error.
955 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
956 Handle class_loader,
957 Handle protection_domain,
958 TRAPS) {
959 Klass* k = NULL;
960 assert(class_name != NULL, "class name must be non NULL");
961
962 if (Signature::is_array(class_name)) {
963 // The name refers to an array. Parse the name.
964 // dimension and object_key in FieldArrayInfo are assigned as a
965 // side-effect of this call
966 SignatureStream ss(class_name, false);
967 int ndims = ss.skip_array_prefix(); // skip all '['s
968 BasicType t = ss.type();
969 if (t != T_OBJECT) {
970 k = Universe::typeArrayKlassObj(t);
971 } else {
972 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
973 }
974 if (k != NULL) {
975 k = k->array_klass_or_null(ndims);
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(THREAD, Compile_lock);
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(THREAD, SystemDictionary_lock);
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 PackageEntry* pkg_entry = NULL;
1201 ModuleEntry* mod_entry = NULL;
1202 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1203 if (pkg_name != NULL) {
1204 if (loader_data != NULL) {
1205 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1206 if (pkg_entry != NULL) {
1207 mod_entry = pkg_entry->module();
1208 // If the archived class is from a module that has been patched at runtime,
1209 // the class cannot be loaded from the archive.
1210 if (mod_entry != NULL && mod_entry->is_patched()) {
1211 return false;
1212 }
1213 }
1214 }
1215 }
1216
1217 if (class_loader.is_null()) {
1218 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1219 // The NULL classloader can load archived class originated from the
1220 // "modules" jimage and the -Xbootclasspath/a. For class from the
1221 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1222 // by the NULL classloader.
1223 if (mod_entry != NULL) {
1224 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1225 // ModuleEntry's location agrees with the archived class' origination.
1226 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1227 return true; // Module class from the "module" jimage
1228 }
1229 }
1230
1231 // If the archived class is not from the "module" jimage, the class can be
1232 // loaded by the NULL classloader if
1233 //
1234 // 1. the class is from the unamed package
1235 // 2. or, the class is not from a module defined in the NULL classloader
1236 // 3. or, the class is from an unamed module
1237 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1238 // the class is from the -Xbootclasspath/a
1239 if (pkg_name == NULL ||
1240 pkg_entry == NULL ||
1241 pkg_entry->in_unnamed_module()) {
1242 assert(mod_entry == NULL ||
1243 mod_entry == loader_data->unnamed_module(),
1244 "the unnamed module is not defined in the classloader");
1245 return true;
1246 }
1247 }
1248 return false;
1249 } else {
1250 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1251 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1252 return res;
1253 }
1254 }
1255
1256 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1257 Handle class_loader, Handle protection_domain,
1258 bool is_superclass, TRAPS) {
1259 assert(super_type->is_shared(), "must be");
1260
1261 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1262 class_loader, protection_domain, is_superclass, CHECK_0);
1263 if (found == super_type) {
1264 return true;
1265 } else {
1266 // The dynamically resolved super type is not the same as the one we used during dump time,
1267 // so we cannot use the child class.
1268 return false;
1269 }
1270 }
1271
1272 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1273 Handle protection_domain, TRAPS) {
1274 // Check the superclass and interfaces. They must be the same
1275 // as in dump time, because the layout of <ik> depends on
1276 // the specific layout of ik->super() and ik->local_interfaces().
1277 //
1278 // If unexpected superclass or interfaces are found, we cannot
1279 // load <ik> from the shared archive.
1280
1281 if (ik->super() != NULL &&
1282 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1283 class_loader, protection_domain, true, THREAD)) {
1284 return false;
1285 }
1286
1287 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1288 int num_interfaces = interfaces->length();
1289 for (int index = 0; index < num_interfaces; index++) {
1290 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1291 return false;
1292 }
1293 }
1294
1295 return true;
1296 }
1297
1298 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1299 Handle class_loader,
1300 Handle protection_domain,
1301 const ClassFileStream *cfs,
1302 TRAPS) {
1303 assert(ik != NULL, "sanity");
1304 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1305 Symbol* class_name = ik->name();
1306
1307 bool visible = is_shared_class_visible(
1308 class_name, ik, class_loader, CHECK_NULL);
1309 if (!visible) {
1310 return NULL;
1311 }
1312
1313 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1314 return NULL;
1315 }
1316
1317 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1318 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1319 if (new_ik != NULL) {
1320 // The class is changed by CFLH. Return the new class. The shared class is
1321 // not used.
1322 return new_ik;
1323 }
1324
1325 // Adjust methods to recover missing data. They need addresses for
1326 // interpreter entry points and their default native method address
1327 // must be reset.
1328
1329 // Updating methods must be done under a lock so multiple
1330 // threads don't update these in parallel
1331 //
1332 // Shared classes are all currently loaded by either the bootstrap or
1333 // internal parallel class loaders, so this will never cause a deadlock
1334 // on a custom class loader lock.
1335
1336 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1337 {
1338 HandleMark hm(THREAD);
1339 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1340 check_loader_lock_contention(lockObject, THREAD);
1341 ObjectLocker ol(lockObject, THREAD, true);
1342 // prohibited package check assumes all classes loaded from archive call
1343 // restore_unshareable_info which calls ik->set_package()
1344 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1345 }
1346
1347 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1348 return ik;
1349 }
1350
1351 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1352 ik->print_class_load_logging(loader_data, NULL, NULL);
1353
1354 // For boot loader, ensure that GetSystemPackage knows that a class in this
1355 // package was loaded.
1356 if (loader_data->is_the_null_class_loader_data()) {
1357 int path_index = ik->shared_classpath_index();
1358 ClassLoader::add_package(ik, path_index, THREAD);
1359 }
1360
1361 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1362 // Only dump the classes that can be stored into CDS archive
1363 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1364 ResourceMark rm(THREAD);
1365 classlist_file->print_cr("%s", ik->name()->as_C_string());
1366 classlist_file->flush();
1367 }
1368 }
1369
1370 // notify a class loaded from shared object
1371 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1372
1373 ik->set_has_passed_fingerprint_check(false);
1374 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1375 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1376 uint64_t cds_fp = ik->get_stored_fingerprint();
1377 if (aot_fp != 0 && aot_fp == cds_fp) {
1378 // This class matches with a class saved in an AOT library
1379 ik->set_has_passed_fingerprint_check(true);
1380 } else {
1381 if (log_is_enabled(Info, class, fingerprint)) {
1382 ResourceMark rm(THREAD);
1383 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1384 }
1385 }
1386 }
1387 }
1388
1389 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1390 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1391 assert(klass->is_shared(), "Must be shared class");
1392 if (klass->class_loader_data() != NULL) {
1393 return;
1394 }
1395
1396 // add super and interfaces first
1397 Klass* super = klass->super();
1398 if (super != NULL && super->class_loader_data() == NULL) {
1399 assert(super->is_instance_klass(), "Super should be instance klass");
1400 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1401 }
1402
1403 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1404 for (int i = 0; i < ifs->length(); i++) {
1405 InstanceKlass* ik = ifs->at(i);
1406 if (ik->class_loader_data() == NULL) {
1407 quick_resolve(ik, loader_data, domain, CHECK);
1408 }
1409 }
1410
1411 klass->restore_unshareable_info(loader_data, domain, THREAD);
1412 load_shared_class_misc(klass, loader_data, CHECK);
1413 Dictionary* dictionary = loader_data->dictionary();
1414 unsigned int hash = dictionary->compute_hash(klass->name());
1415 dictionary->add_klass(hash, klass->name(), klass);
1416 add_to_hierarchy(klass, CHECK);
1417 assert(klass->is_loaded(), "Must be in at least loaded state");
1418 }
1419 #endif // INCLUDE_CDS
1420
1421 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1422
1423 if (class_loader.is_null()) {
1424 ResourceMark rm(THREAD);
1425 PackageEntry* pkg_entry = NULL;
1426 bool search_only_bootloader_append = false;
1427 ClassLoaderData *loader_data = class_loader_data(class_loader);
1428
1429 // Find the package in the boot loader's package entry table.
1430 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1431 if (pkg_name != NULL) {
1432 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1433 }
1434
1435 // Prior to attempting to load the class, enforce the boot loader's
1436 // visibility boundaries.
1437 if (!Universe::is_module_initialized()) {
1438 // During bootstrapping, prior to module initialization, any
1439 // class attempting to be loaded must be checked against the
1440 // java.base packages in the boot loader's PackageEntryTable.
1441 // No class outside of java.base is allowed to be loaded during
1442 // this bootstrapping window.
1443 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1444 // Class is either in the unnamed package or in
1445 // a named package within the unnamed module. Either
1446 // case is outside of java.base, do not attempt to
1447 // load the class post java.base definition. If
1448 // java.base has not been defined, let the class load
1449 // and its package will be checked later by
1450 // ModuleEntryTable::verify_javabase_packages.
1451 if (ModuleEntryTable::javabase_defined()) {
1452 return NULL;
1453 }
1454 } else {
1455 // Check that the class' package is defined within java.base.
1456 ModuleEntry* mod_entry = pkg_entry->module();
1457 Symbol* mod_entry_name = mod_entry->name();
1458 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1459 return NULL;
1460 }
1461 }
1462 } else {
1463 // After the module system has been initialized, check if the class'
1464 // package is in a module defined to the boot loader.
1465 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1466 // Class is either in the unnamed package, in a named package
1467 // within a module not defined to the boot loader or in a
1468 // a named package within the unnamed module. In all cases,
1469 // limit visibility to search for the class only in the boot
1470 // loader's append path.
1471 if (!ClassLoader::has_bootclasspath_append()) {
1472 // If there is no bootclasspath append entry, no need to continue
1473 // searching.
1474 return NULL;
1475 }
1476 search_only_bootloader_append = true;
1477 }
1478 }
1479
1480 // Prior to bootstrapping's module initialization, never load a class outside
1481 // of the boot loader's module path
1482 assert(Universe::is_module_initialized() ||
1483 !search_only_bootloader_append,
1484 "Attempt to load a class outside of boot loader's module path");
1485
1486 // Search for classes in the CDS archive.
1487 InstanceKlass* k = NULL;
1488 {
1489 #if INCLUDE_CDS
1490 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1491 k = load_shared_boot_class(class_name, THREAD);
1492 #endif
1493 }
1494
1495 if (k == NULL) {
1496 // Use VM class loader
1497 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1498 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1499 }
1500
1501 // find_or_define_instance_class may return a different InstanceKlass
1502 if (k != NULL) {
1503 InstanceKlass* defined_k =
1504 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1505 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1506 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1507 assert(defined_k != NULL, "Should have a klass if there's no exception");
1508 loader_data->add_to_deallocate_list(k);
1509 k = defined_k;
1510 } else if (HAS_PENDING_EXCEPTION) {
1511 loader_data->add_to_deallocate_list(k);
1512 return NULL;
1513 }
1514 }
1515 return k;
1516 } else {
1517 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1518 ResourceMark rm(THREAD);
1519
1520 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1521 JavaThread* jt = (JavaThread*) THREAD;
1522
1523 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1524 ClassLoader::perf_app_classload_selftime(),
1525 ClassLoader::perf_app_classload_count(),
1526 jt->get_thread_stat()->perf_recursion_counts_addr(),
1527 jt->get_thread_stat()->perf_timers_addr(),
1528 PerfClassTraceTime::CLASS_LOAD);
1529
1530 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1531 // Translate to external class name format, i.e., convert '/' chars to '.'
1532 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1533
1534 JavaValue result(T_OBJECT);
1535
1536 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1537
1538 // Call public unsynchronized loadClass(String) directly for all class loaders.
1539 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1540 // acquire a class-name based lock rather than the class loader object lock.
1541 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1542 JavaCalls::call_virtual(&result,
1543 class_loader,
1544 spec_klass,
1545 vmSymbols::loadClass_name(),
1546 vmSymbols::string_class_signature(),
1547 string,
1548 CHECK_NULL);
1549
1550 assert(result.get_type() == T_OBJECT, "just checking");
1551 oop obj = (oop) result.get_jobject();
1552
1553 // Primitive classes return null since forName() can not be
1554 // used to obtain any of the Class objects representing primitives or void
1555 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1556 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1557 // For user defined Java class loaders, check that the name returned is
1558 // the same as that requested. This check is done for the bootstrap
1559 // loader when parsing the class file.
1560 if (class_name == k->name()) {
1561 return k;
1562 }
1563 }
1564 // Class is not found or has the wrong name, return NULL
1565 return NULL;
1566 }
1567 }
1568
1569 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1570 EventClassDefine event;
1571 if (event.should_commit()) {
1572 event.set_definedClass(k);
1573 event.set_definingClassLoader(def_cld);
1574 event.commit();
1575 }
1576 }
1577
1578 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1579
1580 HandleMark hm(THREAD);
1581 ClassLoaderData* loader_data = k->class_loader_data();
1582 Handle class_loader_h(THREAD, loader_data->class_loader());
1583
1584 // for bootstrap and other parallel classloaders don't acquire lock,
1585 // use placeholder token
1586 // If a parallelCapable class loader calls define_instance_class instead of
1587 // find_or_define_instance_class to get here, we have a timing
1588 // hole with systemDictionary updates and check_constraints
1589 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1590 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1591 compute_loader_lock_object(class_loader_h, THREAD)),
1592 "define called without lock");
1593 }
1594
1595 // Check class-loading constraints. Throw exception if violation is detected.
1596 // Grabs and releases SystemDictionary_lock
1597 // The check_constraints/find_class call and update_dictionary sequence
1598 // must be "atomic" for a specific class/classloader pair so we never
1599 // define two different instanceKlasses for that class/classloader pair.
1600 // Existing classloaders will call define_instance_class with the
1601 // classloader lock held
1602 // Parallel classloaders will call find_or_define_instance_class
1603 // which will require a token to perform the define class
1604 Symbol* name_h = k->name();
1605 Dictionary* dictionary = loader_data->dictionary();
1606 unsigned int d_hash = dictionary->compute_hash(name_h);
1607 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1608
1609 // Register class just loaded with class loader (placed in ArrayList)
1610 // Note we do this before updating the dictionary, as this can
1611 // fail with an OutOfMemoryError (if it does, we will *not* put this
1612 // class in the dictionary and will not update the class hierarchy).
1613 // JVMTI FollowReferences needs to find the classes this way.
1614 if (k->class_loader() != NULL) {
1615 methodHandle m(THREAD, Universe::loader_addClass_method());
1616 JavaValue result(T_VOID);
1617 JavaCallArguments args(class_loader_h);
1618 args.push_oop(Handle(THREAD, k->java_mirror()));
1619 JavaCalls::call(&result, m, &args, CHECK);
1620 }
1621
1622 // Add the new class. We need recompile lock during update of CHA.
1623 {
1624 unsigned int p_hash = placeholders()->compute_hash(name_h);
1625 int p_index = placeholders()->hash_to_index(p_hash);
1626
1627 MutexLocker mu_r(THREAD, Compile_lock);
1628
1629 // Add to class hierarchy, initialize vtables, and do possible
1630 // deoptimizations.
1631 add_to_hierarchy(k, CHECK); // No exception, but can block
1632
1633 // Add to systemDictionary - so other classes can see it.
1634 // Grabs and releases SystemDictionary_lock
1635 update_dictionary(d_hash, p_index, p_hash,
1636 k, class_loader_h, THREAD);
1637 }
1638 k->eager_initialize(THREAD);
1639
1640 // notify jvmti
1641 if (JvmtiExport::should_post_class_load()) {
1642 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1643 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1644
1645 }
1646 post_class_define_event(k, loader_data);
1647 }
1648
1649 // Support parallel classloading
1650 // All parallel class loaders, including bootstrap classloader
1651 // lock a placeholder entry for this class/class_loader pair
1652 // to allow parallel defines of different classes for this class loader
1653 // With AllowParallelDefine flag==true, in case they do not synchronize around
1654 // FindLoadedClass/DefineClass, calls, we check for parallel
1655 // loading for them, wait if a defineClass is in progress
1656 // and return the initial requestor's results
1657 // This flag does not apply to the bootstrap classloader.
1658 // With AllowParallelDefine flag==false, call through to define_instance_class
1659 // which will throw LinkageError: duplicate class definition.
1660 // False is the requested default.
1661 // For better performance, the class loaders should synchronize
1662 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1663 // potentially waste time reading and parsing the bytestream.
1664 // Note: VM callers should ensure consistency of k/class_name,class_loader
1665 // Be careful when modifying this code: once you have run
1666 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1667 // you need to find_and_remove it before returning.
1668 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1669 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1670 InstanceKlass* k, TRAPS) {
1671
1672 Symbol* name_h = k->name(); // passed in class_name may be null
1673 ClassLoaderData* loader_data = class_loader_data(class_loader);
1674 Dictionary* dictionary = loader_data->dictionary();
1675
1676 unsigned int d_hash = dictionary->compute_hash(name_h);
1677
1678 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1679 unsigned int p_hash = placeholders()->compute_hash(name_h);
1680 int p_index = placeholders()->hash_to_index(p_hash);
1681 PlaceholderEntry* probe;
1682
1683 {
1684 MutexLocker mu(THREAD, SystemDictionary_lock);
1685 // First check if class already defined
1686 if (is_parallelDefine(class_loader)) {
1687 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1688 if (check != NULL) {
1689 return check;
1690 }
1691 }
1692
1693 // Acquire define token for this class/classloader
1694 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1695 // Wait if another thread defining in parallel
1696 // All threads wait - even those that will throw duplicate class: otherwise
1697 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1698 // if other thread has not finished updating dictionary
1699 while (probe->definer() != NULL) {
1700 SystemDictionary_lock->wait();
1701 }
1702 // Only special cases allow parallel defines and can use other thread's results
1703 // Other cases fall through, and may run into duplicate defines
1704 // caught by finding an entry in the SystemDictionary
1705 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1706 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1707 SystemDictionary_lock->notify_all();
1708 #ifdef ASSERT
1709 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1710 assert(check != NULL, "definer missed recording success");
1711 #endif
1712 return probe->instance_klass();
1713 } else {
1714 // This thread will define the class (even if earlier thread tried and had an error)
1715 probe->set_definer(THREAD);
1716 }
1717 }
1718
1719 define_instance_class(k, THREAD);
1720
1721 Handle linkage_exception = Handle(); // null handle
1722
1723 // definer must notify any waiting threads
1724 {
1725 MutexLocker mu(THREAD, SystemDictionary_lock);
1726 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1727 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1728 if (probe != NULL) {
1729 if (HAS_PENDING_EXCEPTION) {
1730 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1731 CLEAR_PENDING_EXCEPTION;
1732 } else {
1733 probe->set_instance_klass(k);
1734 }
1735 probe->set_definer(NULL);
1736 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1737 SystemDictionary_lock->notify_all();
1738 }
1739 }
1740
1741 // Can't throw exception while holding lock due to rank ordering
1742 if (linkage_exception() != NULL) {
1743 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1744 }
1745
1746 return k;
1747 }
1748
1749 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1750 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1751 if (class_loader.is_null()) {
1752 return Handle(THREAD, _system_loader_lock_obj);
1753 } else {
1754 return class_loader;
1755 }
1756 }
1757
1758 // This method is added to check how often we have to wait to grab loader
1759 // lock. The results are being recorded in the performance counters defined in
1760 // ClassLoader::_sync_systemLoaderLockContentionRate and
1761 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1762 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1763 if (!UsePerfData) {
1764 return;
1765 }
1766
1767 assert(!loader_lock.is_null(), "NULL lock object");
1768
1769 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1770 == ObjectSynchronizer::owner_other) {
1771 // contention will likely happen, so increment the corresponding
1772 // contention counter.
1773 if (loader_lock() == _system_loader_lock_obj) {
1774 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1775 } else {
1776 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1777 }
1778 }
1779 }
1780
1781 // ----------------------------------------------------------------------------
1782 // Lookup
1783
1784 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1785 Symbol* class_name,
1786 Dictionary* dictionary) {
1787 assert_locked_or_safepoint(SystemDictionary_lock);
1788 int index = dictionary->hash_to_index(hash);
1789 return dictionary->find_class(index, hash, class_name);
1790 }
1791
1792
1793 // Basic find on classes in the midst of being loaded
1794 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1795 ClassLoaderData* loader_data) {
1796 assert_locked_or_safepoint(SystemDictionary_lock);
1797 unsigned int p_hash = placeholders()->compute_hash(class_name);
1798 int p_index = placeholders()->hash_to_index(p_hash);
1799 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1800 }
1801
1802
1803 // Used for assertions and verification only
1804 // Precalculating the hash and index is an optimization because there are many lookups
1805 // before adding the class.
1806 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1807 assert_locked_or_safepoint(SystemDictionary_lock);
1808 #ifndef ASSERT
1809 guarantee(VerifyBeforeGC ||
1810 VerifyDuringGC ||
1811 VerifyBeforeExit ||
1812 VerifyDuringStartup ||
1813 VerifyAfterGC, "too expensive");
1814 #endif
1815
1816 Dictionary* dictionary = loader_data->dictionary();
1817 unsigned int d_hash = dictionary->compute_hash(class_name);
1818 return find_class(d_hash, class_name, dictionary);
1819 }
1820
1821
1822 // ----------------------------------------------------------------------------
1823 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1824 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1825 // before a new class is used.
1826
1827 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1828 assert(k != NULL, "just checking");
1829 if (Universe::is_fully_initialized()) {
1830 assert_locked_or_safepoint(Compile_lock);
1831 }
1832
1833 k->set_init_state(InstanceKlass::loaded);
1834 // make sure init_state store is already done.
1835 // The compiler reads the hierarchy outside of the Compile_lock.
1836 // Access ordering is used to add to hierarchy.
1837
1838 // Link into hierachy.
1839 k->append_to_sibling_list(); // add to superklass/sibling list
1840 k->process_interfaces(THREAD); // handle all "implements" declarations
1841
1842 // Now flush all code that depended on old class hierarchy.
1843 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1844 if (Universe::is_fully_initialized()) {
1845 CodeCache::flush_dependents_on(k);
1846 }
1847 }
1848
1849 // ----------------------------------------------------------------------------
1850 // GC support
1851
1852 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1853 // Note: anonymous classes are not in the SD.
1854 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1855
1856 bool unloading_occurred;
1857 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1858 {
1859 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1860 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1861 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1862 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1863 if (unloading_occurred) {
1864 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1865 JFR_ONLY(Jfr::on_unloading_classes();)
1866
1867 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1868 ClassLoaderDataGraph::clean_module_and_package_info();
1869 constraints()->purge_loader_constraints();
1870 resolution_errors()->purge_resolution_errors();
1871 }
1872 }
1873
1874 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1875
1876 if (unloading_occurred) {
1877 SymbolTable::trigger_cleanup();
1878
1879 // Oops referenced by the protection domain cache table may get unreachable independently
1880 // of the class loader (eg. cached protection domain oops). So we need to
1881 // explicitly unlink them here.
1882 // All protection domain oops are linked to the caller class, so if nothing
1883 // unloads, this is not needed.
1884 _pd_cache_table->trigger_cleanup();
1885 }
1886
1887 return unloading_occurred;
1888 }
1889
1890 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1891 f->do_oop(&_java_system_loader);
1892 f->do_oop(&_java_platform_loader);
1893 f->do_oop(&_system_loader_lock_obj);
1894 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1895
1896 // Visit extra methods
1897 invoke_method_table()->oops_do(f);
1898
1899 if (include_handles) {
1900 OopStorageSet::vm_global()->oops_do(f);
1901 }
1902 }
1903
1904 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1905 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1906 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1907 it->push(well_known_klass_addr((WKID)id));
1908 }
1909 }
1910
1911 void SystemDictionary::methods_do(void f(Method*)) {
1912 // Walk methods in loaded classes
1913 MutexLocker ml(ClassLoaderDataGraph_lock);
1914 ClassLoaderDataGraph::methods_do(f);
1915 // Walk method handle intrinsics
1916 invoke_method_table()->methods_do(f);
1917 }
1918
1919 // ----------------------------------------------------------------------------
1920 // Initialization
1921
1922 void SystemDictionary::initialize(TRAPS) {
1923 // Allocate arrays
1924 _placeholders = new PlaceholderTable(_placeholder_table_size);
1925 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1926 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1927 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1928 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1929
1930 // Allocate private object used as system class loader lock
1931 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1932 // Initialize basic classes
1933 resolve_well_known_classes(CHECK);
1934 }
1935
1936 // Compact table of directions on the initialization of klasses:
1937 static const short wk_init_info[] = {
1938 #define WK_KLASS_INIT_INFO(name, symbol) \
1939 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1940
1941 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1942 #undef WK_KLASS_INIT_INFO
1943 0
1944 };
1945
1946 #ifdef ASSERT
1947 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1948 int sid;
1949 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1950 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1951 if (class_name == symbol) {
1952 return true;
1953 }
1954 }
1955 return false;
1956 }
1957 #endif
1958
1959 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1960 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1961 int sid = wk_init_info[id - FIRST_WKID];
1962 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1963 InstanceKlass** klassp = &_well_known_klasses[id];
1964
1965 #if INCLUDE_CDS
1966 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
1967 InstanceKlass* k = *klassp;
1968 assert(k->is_shared_boot_class(), "must be");
1969
1970 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
1971 quick_resolve(k, loader_data, Handle(), CHECK_false);
1972 return true;
1973 }
1974 #endif // INCLUDE_CDS
1975
1976 if (!is_wk_klass_loaded(*klassp)) {
1977 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
1978 (*klassp) = InstanceKlass::cast(k);
1979 }
1980 return ((*klassp) != NULL);
1981 }
1982
1983 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1984 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1985 for (int id = (int)start_id; id < (int)limit_id; id++) {
1986 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1987 resolve_wk_klass((WKID)id, CHECK);
1988 }
1989
1990 // move the starting value forward to the limit:
1991 start_id = limit_id;
1992 }
1993
1994 void SystemDictionary::resolve_well_known_classes(TRAPS) {
1995 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
1996
1997 // Create the ModuleEntry for java.base. This call needs to be done here,
1998 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1999 ClassLoader::classLoader_init2(CHECK);
2000
2001 // Preload commonly used klasses
2002 WKID scan = FIRST_WKID;
2003 // first do Object, then String, Class
2004 #if INCLUDE_CDS
2005 if (UseSharedSpaces) {
2006 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2007
2008 // It's unsafe to access the archived heap regions before they
2009 // are fixed up, so we must do the fixup as early as possible
2010 // before the archived java objects are accessed by functions
2011 // such as java_lang_Class::restore_archived_mirror and
2012 // ConstantPool::restore_unshareable_info (restores the archived
2013 // resolved_references array object).
2014 //
2015 // HeapShared::fixup_mapped_heap_regions() fills the empty
2016 // spaces in the archived heap regions and may use
2017 // SystemDictionary::Object_klass(), so we can do this only after
2018 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2019 // call. No mirror objects are accessed/restored in the above call.
2020 // Mirrors are restored after java.lang.Class is loaded.
2021 HeapShared::fixup_mapped_heap_regions();
2022
2023 // Initialize the constant pool for the Object_class
2024 assert(Object_klass()->is_shared(), "must be");
2025 Object_klass()->constants()->restore_unshareable_info(CHECK);
2026 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2027 } else
2028 #endif
2029 {
2030 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2031 }
2032
2033 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2034
2035 java_lang_Object::register_natives(CHECK);
2036
2037 // Calculate offsets for String and Class classes since they are loaded and
2038 // can be used after this point.
2039 java_lang_String::compute_offsets();
2040 java_lang_Class::compute_offsets();
2041
2042 // Fixup mirrors for classes loaded before java.lang.Class.
2043 Universe::initialize_basic_type_mirrors(CHECK);
2044 Universe::fixup_mirrors(CHECK);
2045
2046 // do a bunch more:
2047 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2048
2049 // Preload ref klasses and set reference types
2050 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2051 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2052
2053 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2054 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2055 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2056 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2057 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2058
2059 // JSR 292 classes
2060 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2061 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2062 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2063 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2064 WKID last = WKID_LIMIT;
2065 resolve_wk_klasses_until(last, scan, CHECK);
2066
2067 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2068 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2069 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2070 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2071 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2072 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2073 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2074 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2075 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2076 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2077
2078 #ifdef ASSERT
2079 if (UseSharedSpaces) {
2080 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2081 "All well known classes must be resolved in JVMTI early phase"));
2082 for (int i = FIRST_WKID; i < last; i++) {
2083 InstanceKlass* k = _well_known_klasses[i];
2084 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2085 }
2086 }
2087 #endif
2088 }
2089
2090 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2091 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2092 BasicType SystemDictionary::box_klass_type(Klass* k) {
2093 assert(k != NULL, "");
2094 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2095 if (_box_klasses[i] == k)
2096 return (BasicType)i;
2097 }
2098 return T_OBJECT;
2099 }
2100
2101 // Constraints on class loaders. The details of the algorithm can be
2102 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2103 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2104 // that the dictionary needs to maintain a set of contraints that
2105 // must be satisfied by all classes in the dictionary.
2106 // if defining is true, then LinkageError if already in dictionary
2107 // if initiating loader, then ok if InstanceKlass matches existing entry
2108
2109 void SystemDictionary::check_constraints(unsigned int d_hash,
2110 InstanceKlass* k,
2111 Handle class_loader,
2112 bool defining,
2113 TRAPS) {
2114 ResourceMark rm(THREAD);
2115 stringStream ss;
2116 bool throwException = false;
2117
2118 {
2119 Symbol *name = k->name();
2120 ClassLoaderData *loader_data = class_loader_data(class_loader);
2121
2122 MutexLocker mu(THREAD, SystemDictionary_lock);
2123
2124 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2125 if (check != NULL) {
2126 // If different InstanceKlass - duplicate class definition,
2127 // else - ok, class loaded by a different thread in parallel.
2128 // We should only have found it if it was done loading and ok to use.
2129 // The dictionary only holds instance classes, placeholders
2130 // also hold array classes.
2131
2132 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2133 if ((defining == true) || (k != check)) {
2134 throwException = true;
2135 ss.print("loader %s", loader_data->loader_name_and_id());
2136 ss.print(" attempted duplicate %s definition for %s. (%s)",
2137 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2138 } else {
2139 return;
2140 }
2141 }
2142
2143 #ifdef ASSERT
2144 Symbol* ph_check = find_placeholder(name, loader_data);
2145 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2146 #endif
2147
2148 if (throwException == false) {
2149 if (constraints()->check_or_update(k, class_loader, name) == false) {
2150 throwException = true;
2151 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2152 ss.print(" wants to load %s %s.",
2153 k->external_kind(), k->external_name());
2154 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2155 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2156 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2157 existing_klass->external_kind(),
2158 existing_klass->class_loader_data()->loader_name_and_id(),
2159 existing_klass->class_in_module_of_loader(false, true));
2160 } else {
2161 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2162 }
2163 }
2164 }
2165 }
2166
2167 // Throw error now if needed (cannot throw while holding
2168 // SystemDictionary_lock because of rank ordering)
2169 if (throwException == true) {
2170 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2171 }
2172 }
2173
2174 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2175 // have been called.
2176 void SystemDictionary::update_dictionary(unsigned int d_hash,
2177 int p_index, unsigned int p_hash,
2178 InstanceKlass* k,
2179 Handle class_loader,
2180 TRAPS) {
2181 // Compile_lock prevents systemDictionary updates during compilations
2182 assert_locked_or_safepoint(Compile_lock);
2183 Symbol* name = k->name();
2184 ClassLoaderData *loader_data = class_loader_data(class_loader);
2185
2186 {
2187 MutexLocker mu1(THREAD, SystemDictionary_lock);
2188
2189 // Make a new dictionary entry.
2190 Dictionary* dictionary = loader_data->dictionary();
2191 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2192 if (sd_check == NULL) {
2193 dictionary->add_klass(d_hash, name, k);
2194 }
2195 #ifdef ASSERT
2196 sd_check = find_class(d_hash, name, dictionary);
2197 assert (sd_check != NULL, "should have entry in dictionary");
2198 // Note: there may be a placeholder entry: for circularity testing
2199 // or for parallel defines
2200 #endif
2201 SystemDictionary_lock->notify_all();
2202 }
2203 }
2204
2205
2206 // Try to find a class name using the loader constraints. The
2207 // loader constraints might know about a class that isn't fully loaded
2208 // yet and these will be ignored.
2209 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2210 Symbol* class_name, Handle class_loader, TRAPS) {
2211
2212 // First see if it has been loaded directly.
2213 // Force the protection domain to be null. (This removes protection checks.)
2214 Handle no_protection_domain;
2215 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2216 no_protection_domain, CHECK_NULL);
2217 if (klass != NULL)
2218 return klass;
2219
2220 // Now look to see if it has been loaded elsewhere, and is subject to
2221 // a loader constraint that would require this loader to return the
2222 // klass that is already loaded.
2223 if (Signature::is_array(class_name)) {
2224 // For array classes, their Klass*s are not kept in the
2225 // constraint table. The element Klass*s are.
2226 SignatureStream ss(class_name, false);
2227 int ndims = ss.skip_array_prefix(); // skip all '['s
2228 BasicType t = ss.type();
2229 if (t != T_OBJECT) {
2230 klass = Universe::typeArrayKlassObj(t);
2231 } else {
2232 MutexLocker mu(THREAD, SystemDictionary_lock);
2233 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2234 }
2235 // If element class already loaded, allocate array klass
2236 if (klass != NULL) {
2237 klass = klass->array_klass_or_null(ndims);
2238 }
2239 } else {
2240 MutexLocker mu(THREAD, SystemDictionary_lock);
2241 // Non-array classes are easy: simply check the constraint table.
2242 klass = constraints()->find_constrained_klass(class_name, class_loader);
2243 }
2244
2245 return klass;
2246 }
2247
2248
2249 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2250 Handle class_loader1,
2251 Handle class_loader2,
2252 Thread* THREAD) {
2253 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2254 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2255
2256 Symbol* constraint_name = NULL;
2257
2258 if (!Signature::is_array(class_name)) {
2259 constraint_name = class_name;
2260 } else {
2261 // For array classes, their Klass*s are not kept in the
2262 // constraint table. The element classes are.
2263 SignatureStream ss(class_name, false);
2264 ss.skip_array_prefix(); // skip all '['s
2265 if (!ss.has_envelope()) {
2266 return true; // primitive types always pass
2267 }
2268 constraint_name = ss.as_symbol();
2269 // Increment refcount to keep constraint_name alive after
2270 // SignatureStream is destructed. It will be decremented below
2271 // before returning.
2272 constraint_name->increment_refcount();
2273 }
2274
2275 Dictionary* dictionary1 = loader_data1->dictionary();
2276 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2277
2278 Dictionary* dictionary2 = loader_data2->dictionary();
2279 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2280
2281 {
2282 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2283 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2284 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2285 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2286 klass2, class_loader2);
2287 if (Signature::is_array(class_name)) {
2288 constraint_name->decrement_refcount();
2289 }
2290 return result;
2291 }
2292 }
2293
2294 // Add entry to resolution error table to record the error when the first
2295 // attempt to resolve a reference to a class has failed.
2296 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2297 Symbol* error, Symbol* message) {
2298 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2299 int index = resolution_errors()->hash_to_index(hash);
2300 {
2301 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2302 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2303 }
2304 }
2305
2306 // Delete a resolution error for RedefineClasses for a constant pool is going away
2307 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2308 resolution_errors()->delete_entry(pool);
2309 }
2310
2311 // Lookup resolution error table. Returns error if found, otherwise NULL.
2312 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2313 Symbol** message) {
2314 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2315 int index = resolution_errors()->hash_to_index(hash);
2316 {
2317 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2318 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2319 if (entry != NULL) {
2320 *message = entry->message();
2321 return entry->error();
2322 } else {
2323 return NULL;
2324 }
2325 }
2326 }
2327
2328
2329 // Signature constraints ensure that callers and callees agree about
2330 // the meaning of type names in their signatures. This routine is the
2331 // intake for constraints. It collects them from several places:
2332 //
2333 // * LinkResolver::resolve_method (if check_access is true) requires
2334 // that the resolving class (the caller) and the defining class of
2335 // the resolved method (the callee) agree on each type in the
2336 // method's signature.
2337 //
2338 // * LinkResolver::resolve_interface_method performs exactly the same
2339 // checks.
2340 //
2341 // * LinkResolver::resolve_field requires that the constant pool
2342 // attempting to link to a field agree with the field's defining
2343 // class about the type of the field signature.
2344 //
2345 // * klassVtable::initialize_vtable requires that, when a class
2346 // overrides a vtable entry allocated by a superclass, that the
2347 // overriding method (i.e., the callee) agree with the superclass
2348 // on each type in the method's signature.
2349 //
2350 // * klassItable::initialize_itable requires that, when a class fills
2351 // in its itables, for each non-abstract method installed in an
2352 // itable, the method (i.e., the callee) agree with the interface
2353 // on each type in the method's signature.
2354 //
2355 // All those methods have a boolean (check_access, checkconstraints)
2356 // which turns off the checks. This is used from specialized contexts
2357 // such as bootstrapping, dumping, and debugging.
2358 //
2359 // No direct constraint is placed between the class and its
2360 // supertypes. Constraints are only placed along linked relations
2361 // between callers and callees. When a method overrides or implements
2362 // an abstract method in a supertype (superclass or interface), the
2363 // constraints are placed as if the supertype were the caller to the
2364 // overriding method. (This works well, since callers to the
2365 // supertype have already established agreement between themselves and
2366 // the supertype.) As a result of all this, a class can disagree with
2367 // its supertype about the meaning of a type name, as long as that
2368 // class neither calls a relevant method of the supertype, nor is
2369 // called (perhaps via an override) from the supertype.
2370 //
2371 //
2372 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2373 //
2374 // Make sure all class components (including arrays) in the given
2375 // signature will be resolved to the same class in both loaders.
2376 // Returns the name of the type that failed a loader constraint check, or
2377 // NULL if no constraint failed. No exception except OOME is thrown.
2378 // Arrays are not added to the loader constraint table, their elements are.
2379 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2380 Handle loader1, Handle loader2,
2381 bool is_method, TRAPS) {
2382 // Nothing to do if loaders are the same.
2383 if (loader1() == loader2()) {
2384 return NULL;
2385 }
2386
2387 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2388 if (ss.is_reference()) {
2389 Symbol* sig = ss.as_symbol();
2390 // Note: In the future, if template-like types can take
2391 // arguments, we will want to recognize them and dig out class
2392 // names hiding inside the argument lists.
2393 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2394 return sig;
2395 }
2396 }
2397 }
2398 return NULL;
2399 }
2400
2401
2402 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2403 Symbol* signature,
2404 TRAPS) {
2405 methodHandle empty;
2406 assert(MethodHandles::is_signature_polymorphic(iid) &&
2407 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2408 iid != vmIntrinsics::_invokeGeneric,
2409 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2410
2411 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2412 int index = invoke_method_table()->hash_to_index(hash);
2413 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2414 methodHandle m;
2415 if (spe == NULL || spe->method() == NULL) {
2416 spe = NULL;
2417 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2418 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2419 if (!Arguments::is_interpreter_only()) {
2420 // Generate a compiled form of the MH intrinsic.
2421 AdapterHandlerLibrary::create_native_wrapper(m);
2422 // Check if have the compiled code.
2423 if (!m->has_compiled_code()) {
2424 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2425 "Out of space in CodeCache for method handle intrinsic");
2426 }
2427 }
2428 // Now grab the lock. We might have to throw away the new method,
2429 // if a racing thread has managed to install one at the same time.
2430 {
2431 MutexLocker ml(THREAD, SystemDictionary_lock);
2432 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2433 if (spe == NULL)
2434 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2435 if (spe->method() == NULL)
2436 spe->set_method(m());
2437 }
2438 }
2439
2440 assert(spe != NULL && spe->method() != NULL, "");
2441 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2442 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2443 "MH intrinsic invariant");
2444 return spe->method();
2445 }
2446
2447 // Helper for unpacking the return value from linkMethod and linkCallSite.
2448 static Method* unpack_method_and_appendix(Handle mname,
2449 Klass* accessing_klass,
2450 objArrayHandle appendix_box,
2451 Handle* appendix_result,
2452 TRAPS) {
2453 if (mname.not_null()) {
2454 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2455 if (m != NULL) {
2456 oop appendix = appendix_box->obj_at(0);
2457 if (TraceMethodHandles) {
2458 #ifndef PRODUCT
2459 ttyLocker ttyl;
2460 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2461 m->print();
2462 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2463 tty->cr();
2464 #endif //PRODUCT
2465 }
2466 (*appendix_result) = Handle(THREAD, appendix);
2467 // the target is stored in the cpCache and if a reference to this
2468 // MemberName is dropped we need a way to make sure the
2469 // class_loader containing this method is kept alive.
2470 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2471 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2472 this_key->record_dependency(m->method_holder());
2473 return mh();
2474 }
2475 }
2476 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2477 }
2478
2479 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2480 Symbol* name,
2481 Symbol* signature,
2482 Klass* accessing_klass,
2483 Handle *appendix_result,
2484 TRAPS) {
2485 assert(THREAD->can_call_java() ,"");
2486 Handle method_type =
2487 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2488
2489 int ref_kind = JVM_REF_invokeVirtual;
2490 oop name_oop = StringTable::intern(name, CHECK_NULL);
2491 Handle name_str (THREAD, name_oop);
2492 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2493 assert(appendix_box->obj_at(0) == NULL, "");
2494
2495 // This should not happen. JDK code should take care of that.
2496 if (accessing_klass == NULL || method_type.is_null()) {
2497 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2498 }
2499
2500 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2501 JavaCallArguments args;
2502 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2503 args.push_int(ref_kind);
2504 args.push_oop(Handle(THREAD, klass->java_mirror()));
2505 args.push_oop(name_str);
2506 args.push_oop(method_type);
2507 args.push_oop(appendix_box);
2508 JavaValue result(T_OBJECT);
2509 JavaCalls::call_static(&result,
2510 SystemDictionary::MethodHandleNatives_klass(),
2511 vmSymbols::linkMethod_name(),
2512 vmSymbols::linkMethod_signature(),
2513 &args, CHECK_NULL);
2514 Handle mname(THREAD, (oop) result.get_jobject());
2515 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2516 }
2517
2518 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2519 // We must ensure that all class loaders everywhere will reach this class, for any client.
2520 // This is a safe bet for public classes in java.lang, such as Object and String.
2521 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2522 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2523 static bool is_always_visible_class(oop mirror) {
2524 Klass* klass = java_lang_Class::as_Klass(mirror);
2525 if (klass->is_objArray_klass()) {
2526 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2527 }
2528 if (klass->is_typeArray_klass()) {
2529 return true; // primitive array
2530 }
2531 assert(klass->is_instance_klass(), "%s", klass->external_name());
2532 return klass->is_public() &&
2533 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2534 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2535 }
2536
2537 // Find or construct the Java mirror (java.lang.Class instance) for
2538 // the given field type signature, as interpreted relative to the
2539 // given class loader. Handles primitives, void, references, arrays,
2540 // and all other reflectable types, except method types.
2541 // N.B. Code in reflection should use this entry point.
2542 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2543 Klass* accessing_klass,
2544 Handle class_loader,
2545 Handle protection_domain,
2546 SignatureStream::FailureMode failure_mode,
2547 TRAPS) {
2548 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2549 "one or the other, or perhaps neither");
2550
2551 // What we have here must be a valid field descriptor,
2552 // and all valid field descriptors are supported.
2553 // Produce the same java.lang.Class that reflection reports.
2554 if (accessing_klass != NULL) {
2555 class_loader = Handle(THREAD, accessing_klass->class_loader());
2556 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2557 }
2558 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2559 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2560 if (mirror_oop == NULL) {
2561 return Handle(); // report failure this way
2562 }
2563 Handle mirror(THREAD, mirror_oop);
2564
2565 if (accessing_klass != NULL) {
2566 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2567 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2568 if (sel_klass != NULL) {
2569 bool fold_type_to_class = true;
2570 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2571 fold_type_to_class, CHECK_NH);
2572 }
2573 }
2574 return mirror;
2575 }
2576
2577
2578 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2579 // signature, as interpreted relative to the given class loader.
2580 // Because of class loader constraints, all method handle usage must be
2581 // consistent with this loader.
2582 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2583 Klass* accessing_klass,
2584 TRAPS) {
2585 Handle empty;
2586 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2587 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2588 int index = invoke_method_table()->hash_to_index(hash);
2589 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2590 if (spe != NULL && spe->method_type() != NULL) {
2591 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2592 return Handle(THREAD, spe->method_type());
2593 } else if (!THREAD->can_call_java()) {
2594 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2595 return Handle(); // do not attempt from within compiler, unless it was cached
2596 }
2597
2598 Handle class_loader, protection_domain;
2599 if (accessing_klass != NULL) {
2600 class_loader = Handle(THREAD, accessing_klass->class_loader());
2601 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2602 }
2603 bool can_be_cached = true;
2604 int npts = ArgumentCount(signature).size();
2605 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2606 int arg = 0;
2607 Handle rt; // the return type from the signature
2608 ResourceMark rm(THREAD);
2609 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2610 oop mirror = NULL;
2611 if (can_be_cached) {
2612 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2613 mirror = ss.as_java_mirror(Handle(), Handle(),
2614 SignatureStream::ReturnNull, CHECK_(empty));
2615 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2616 // Fall back to accessing_klass context.
2617 can_be_cached = false;
2618 }
2619 }
2620 if (!can_be_cached) {
2621 // Resolve, throwing a real error if it doesn't work.
2622 mirror = ss.as_java_mirror(class_loader, protection_domain,
2623 SignatureStream::NCDFError, CHECK_(empty));
2624 }
2625 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2626 if (ss.at_return_type())
2627 rt = Handle(THREAD, mirror);
2628 else
2629 pts->obj_at_put(arg++, mirror);
2630
2631 // Check accessibility.
2632 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2633 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2634 mirror = NULL; // safety
2635 // Emulate ConstantPool::verify_constant_pool_resolve.
2636 bool fold_type_to_class = true;
2637 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2638 fold_type_to_class, CHECK_(empty));
2639 }
2640 }
2641 assert(arg == npts, "");
2642
2643 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2644 JavaCallArguments args(Handle(THREAD, rt()));
2645 args.push_oop(pts);
2646 JavaValue result(T_OBJECT);
2647 JavaCalls::call_static(&result,
2648 SystemDictionary::MethodHandleNatives_klass(),
2649 vmSymbols::findMethodHandleType_name(),
2650 vmSymbols::findMethodHandleType_signature(),
2651 &args, CHECK_(empty));
2652 Handle method_type(THREAD, (oop) result.get_jobject());
2653
2654 if (can_be_cached) {
2655 // We can cache this MethodType inside the JVM.
2656 MutexLocker ml(THREAD, SystemDictionary_lock);
2657 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2658 if (spe == NULL)
2659 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2660 if (spe->method_type() == NULL) {
2661 spe->set_method_type(method_type());
2662 }
2663 }
2664
2665 // report back to the caller with the MethodType
2666 return method_type;
2667 }
2668
2669 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2670 Klass* accessing_klass,
2671 TRAPS) {
2672 Handle empty;
2673 ResourceMark rm(THREAD);
2674 SignatureStream ss(signature, /*is_method=*/ false);
2675 if (!ss.is_done()) {
2676 Handle class_loader, protection_domain;
2677 if (accessing_klass != NULL) {
2678 class_loader = Handle(THREAD, accessing_klass->class_loader());
2679 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2680 }
2681 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2682 ss.next();
2683 if (ss.is_done()) {
2684 return Handle(THREAD, mirror);
2685 }
2686 }
2687 return empty;
2688 }
2689
2690 // Ask Java code to find or construct a method handle constant.
2691 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2692 int ref_kind, //e.g., JVM_REF_invokeVirtual
2693 Klass* callee,
2694 Symbol* name,
2695 Symbol* signature,
2696 TRAPS) {
2697 Handle empty;
2698 if (caller == NULL) {
2699 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2700 }
2701 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2702 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2703
2704 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2705 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2706 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2707 java_lang_invoke_MemberName::set_name (mname(), name_str());
2708 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2709 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2710
2711 if (ref_kind == JVM_REF_invokeVirtual &&
2712 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2713 // Skip resolution for public signature polymorphic methods such as
2714 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2715 // They require appendix argument which MemberName resolution doesn't handle.
2716 // There's special logic on JDK side to handle them
2717 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2718 } else {
2719 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2720 }
2721
2722 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2723 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2724
2725 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2726 JavaCallArguments args;
2727 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2728 args.push_int(ref_kind);
2729 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2730 args.push_oop(name_str);
2731 args.push_oop(type);
2732 JavaValue result(T_OBJECT);
2733 JavaCalls::call_static(&result,
2734 SystemDictionary::MethodHandleNatives_klass(),
2735 vmSymbols::linkMethodHandleConstant_name(),
2736 vmSymbols::linkMethodHandleConstant_signature(),
2737 &args, CHECK_(empty));
2738 return Handle(THREAD, (oop) result.get_jobject());
2739 }
2740
2741 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2742 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2743 // with linkage results being stored back into the bootstrap specifier.
2744 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2745 // Resolve the bootstrap specifier, its name, type, and static arguments
2746 bootstrap_specifier.resolve_bsm(CHECK);
2747
2748 // This should not happen. JDK code should take care of that.
2749 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2750 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2751 }
2752
2753 bool is_indy = bootstrap_specifier.is_method_call();
2754 objArrayHandle appendix_box;
2755 if (is_indy) {
2756 // Some method calls may require an appendix argument. Arrange to receive it.
2757 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2758 assert(appendix_box->obj_at(0) == NULL, "");
2759 }
2760
2761 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2762 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2763 JavaCallArguments args;
2764 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2765 args.push_int(bootstrap_specifier.bss_index());
2766 args.push_oop(bootstrap_specifier.bsm());
2767 args.push_oop(bootstrap_specifier.name_arg());
2768 args.push_oop(bootstrap_specifier.type_arg());
2769 args.push_oop(bootstrap_specifier.arg_values());
2770 if (is_indy) {
2771 args.push_oop(appendix_box);
2772 }
2773 JavaValue result(T_OBJECT);
2774 JavaCalls::call_static(&result,
2775 SystemDictionary::MethodHandleNatives_klass(),
2776 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2777 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2778 &args, CHECK);
2779
2780 Handle value(THREAD, (oop) result.get_jobject());
2781 if (is_indy) {
2782 Handle appendix;
2783 Method* method = unpack_method_and_appendix(value,
2784 bootstrap_specifier.caller(),
2785 appendix_box,
2786 &appendix, CHECK);
2787 methodHandle mh(THREAD, method);
2788 bootstrap_specifier.set_resolved_method(mh, appendix);
2789 } else {
2790 bootstrap_specifier.set_resolved_value(value);
2791 }
2792
2793 // sanity check
2794 assert(bootstrap_specifier.is_resolved() ||
2795 (bootstrap_specifier.is_method_call() &&
2796 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2797 }
2798
2799 // Protection domain cache table handling
2800
2801 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2802 return _pd_cache_table->get(protection_domain);
2803 }
2804
2805 // ----------------------------------------------------------------------------
2806
2807 void SystemDictionary::print_on(outputStream *st) {
2808 CDS_ONLY(SystemDictionaryShared::print_on(st));
2809 GCMutexLocker mu(SystemDictionary_lock);
2810
2811 ClassLoaderDataGraph::print_dictionary(st);
2812
2813 // Placeholders
2814 placeholders()->print_on(st);
2815 st->cr();
2816
2817 // loader constraints - print under SD_lock
2818 constraints()->print_on(st);
2819 st->cr();
2820
2821 _pd_cache_table->print_on(st);
2822 st->cr();
2823 }
2824
2825 void SystemDictionary::print() { print_on(tty); }
2826
2827 void SystemDictionary::verify() {
2828 guarantee(constraints() != NULL,
2829 "Verify of loader constraints failed");
2830 guarantee(placeholders()->number_of_entries() >= 0,
2831 "Verify of placeholders failed");
2832
2833 GCMutexLocker mu(SystemDictionary_lock);
2834
2835 // Verify dictionary
2836 ClassLoaderDataGraph::verify_dictionary();
2837
2838 placeholders()->verify();
2839
2840 // Verify constraint table
2841 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2842 constraints()->verify(placeholders());
2843
2844 _pd_cache_table->verify();
2845 }
2846
2847 void SystemDictionary::dump(outputStream *st, bool verbose) {
2848 assert_locked_or_safepoint(SystemDictionary_lock);
2849 if (verbose) {
2850 print_on(st);
2851 } else {
2852 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2853 ClassLoaderDataGraph::print_table_statistics(st);
2854 placeholders()->print_table_statistics(st, "Placeholder Table");
2855 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2856 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2857 }
2858 }
2859
2860 TableStatistics SystemDictionary::placeholders_statistics() {
2861 MutexLocker ml(SystemDictionary_lock);
2862 return placeholders()->statistics_calculate();
2863 }
2864
2865 TableStatistics SystemDictionary::loader_constraints_statistics() {
2866 MutexLocker ml(SystemDictionary_lock);
2867 return constraints()->statistics_calculate();
2868 }
2869
2870 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2871 MutexLocker ml(SystemDictionary_lock);
2872 return pd_cache_table()->statistics_calculate();
2873 }
2874
2875 // Utility for dumping dictionaries.
2876 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2877 DCmdWithParser(output, heap),
2878 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2879 "BOOLEAN", false, "false") {
2880 _dcmdparser.add_dcmd_option(&_verbose);
2881 }
2882
2883 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2884 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2885 _verbose.value());
2886 VMThread::execute(&dumper);
2887 }
2888
2889 int SystemDictionaryDCmd::num_arguments() {
2890 ResourceMark rm;
2891 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2892 if (dcmd != NULL) {
2893 DCmdMark mark(dcmd);
2894 return dcmd->_dcmdparser.num_arguments();
2895 } else {
2896 return 0;
2897 }
2898 }