1 /*
2 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/symbolTable.hpp"
44 #include "classfile/systemDictionary.hpp"
45 #include "classfile/vmSymbols.hpp"
46 #include "code/codeCache.hpp"
47 #include "compiler/compileBroker.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/oopStorage.inline.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "interpreter/bytecodeStream.hpp"
52 #include "interpreter/interpreter.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "logging/log.hpp"
55 #include "logging/logStream.hpp"
56 #include "memory/filemap.hpp"
57 #include "memory/heapShared.hpp"
58 #include "memory/metaspaceClosure.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/access.inline.hpp"
63 #include "oops/instanceKlass.hpp"
64 #include "oops/instanceRefKlass.hpp"
65 #include "oops/klass.inline.hpp"
66 #include "oops/method.inline.hpp"
67 #include "oops/methodData.hpp"
68 #include "oops/objArrayKlass.hpp"
69 #include "oops/objArrayOop.inline.hpp"
70 #include "oops/oop.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/fieldType.hpp"
78 #include "runtime/handles.inline.hpp"
79 #include "runtime/java.hpp"
80 #include "runtime/javaCalls.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/orderAccess.hpp"
83 #include "runtime/sharedRuntime.hpp"
84 #include "runtime/signature.hpp"
85 #include "services/classLoadingService.hpp"
86 #include "services/diagnosticCommand.hpp"
87 #include "services/threadService.hpp"
88 #include "utilities/macros.hpp"
89 #if INCLUDE_CDS
90 #include "classfile/systemDictionaryShared.hpp"
91 #endif
92 #if INCLUDE_JFR
93 #include "jfr/jfr.hpp"
94 #endif
95
96 PlaceholderTable* SystemDictionary::_placeholders = NULL;
97 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
98 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
99 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
100 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
101
102 oop SystemDictionary::_system_loader_lock_obj = NULL;
103
104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
105 = { NULL /*, NULL...*/ };
106
107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
108
109 oop SystemDictionary::_java_system_loader = NULL;
110 oop SystemDictionary::_java_platform_loader = NULL;
111
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118 // ----------------------------------------------------------------------------
119 // Java-level SystemLoader and PlatformLoader
120
121 oop SystemDictionary::java_system_loader() {
122 return _java_system_loader;
123 }
124
125 oop SystemDictionary::java_platform_loader() {
126 return _java_platform_loader;
127 }
128
129 void SystemDictionary::compute_java_loaders(TRAPS) {
130 JavaValue result(T_OBJECT);
131 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
132 JavaCalls::call_static(&result,
133 class_loader_klass,
134 vmSymbols::getSystemClassLoader_name(),
135 vmSymbols::void_classloader_signature(),
136 CHECK);
137
138 _java_system_loader = (oop)result.get_jobject();
139
140 JavaCalls::call_static(&result,
141 class_loader_klass,
142 vmSymbols::getPlatformClassLoader_name(),
143 vmSymbols::void_classloader_signature(),
144 CHECK);
145
146 _java_platform_loader = (oop)result.get_jobject();
147 }
148
149 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
150 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
151 return ClassLoaderDataGraph::find_or_create(class_loader);
152 }
153
154 // ----------------------------------------------------------------------------
155 // Parallel class loading check
156
157 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
158 if (class_loader.is_null()) return true;
159 if (AlwaysLockClassLoader) return false;
160 return java_lang_ClassLoader::parallelCapable(class_loader());
161 }
162 // ----------------------------------------------------------------------------
163 // ParallelDefineClass flag does not apply to bootclass loader
164 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
165 if (class_loader.is_null()) return false;
166 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
167 return true;
168 }
169 return false;
170 }
171
172 // Returns true if the passed class loader is the builtin application class loader
173 // or a custom system class loader. A customer system class loader can be
174 // specified via -Djava.system.class.loader.
175 bool SystemDictionary::is_system_class_loader(oop class_loader) {
176 if (class_loader == NULL) {
177 return false;
178 }
179 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
180 class_loader == _java_system_loader);
181 }
182
183 // Returns true if the passed class loader is the platform class loader.
184 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
185 if (class_loader == NULL) {
186 return false;
187 }
188 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
189 }
190
191 // ----------------------------------------------------------------------------
192 // Resolving of classes
193
194 // Forwards to resolve_or_null
195
196 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
197 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
198 if (HAS_PENDING_EXCEPTION || klass == NULL) {
199 // can return a null klass
200 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
201 }
202 return klass;
203 }
204
205 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
206 bool throw_error,
207 Klass* klass, TRAPS) {
208 if (HAS_PENDING_EXCEPTION) {
209 // If we have a pending exception we forward it to the caller, unless throw_error is true,
210 // in which case we have to check whether the pending exception is a ClassNotFoundException,
211 // and if so convert it to a NoClassDefFoundError
212 // And chain the original ClassNotFoundException
213 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
214 ResourceMark rm(THREAD);
215 assert(klass == NULL, "Should not have result with exception pending");
216 Handle e(THREAD, PENDING_EXCEPTION);
217 CLEAR_PENDING_EXCEPTION;
218 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
219 } else {
220 return NULL;
221 }
222 }
223 // Class not found, throw appropriate error or exception depending on value of throw_error
224 if (klass == NULL) {
225 ResourceMark rm(THREAD);
226 if (throw_error) {
227 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
228 } else {
229 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
230 }
231 }
232 return klass;
233 }
234
235
236 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
237 bool throw_error, TRAPS)
238 {
239 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
240 }
241
242
243 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
244
245 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
246 if (FieldType::is_array(class_name)) {
247 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
248 } else {
249 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
250 }
251 }
252
253 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
254 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
255 Handle class_loader,
256 Handle protection_domain,
257 TRAPS) {
258 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
259 if (FieldType::is_obj(class_name)) {
260 ResourceMark rm(THREAD);
261 // Ignore wrapping L and ;.
262 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
263 class_name->utf8_length() - 2);
264 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
265 } else {
266 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
267 }
268 }
269
270 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
271 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
272 }
273
274 // Forwards to resolve_instance_class_or_null
275
276 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
277 Handle class_loader,
278 Handle protection_domain,
279 TRAPS) {
280 assert(FieldType::is_array(class_name), "must be array");
281 Klass* k = NULL;
282 FieldArrayInfo fd;
283 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
284 // of this call
285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
286 if (t == T_OBJECT) {
287 // naked oop "k" is OK here -- we assign back into it
288 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
289 class_loader,
290 protection_domain,
291 CHECK_NULL);
292 if (k != NULL) {
293 k = k->array_klass(fd.dimension(), CHECK_NULL);
294 }
295 } else {
296 k = Universe::typeArrayKlassObj(t);
297 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
298 }
299 return k;
300 }
301
302
303 // Must be called for any super-class or super-interface resolution
304 // during class definition to allow class circularity checking
305 // super-interface callers:
306 // parse_interfaces - for defineClass & jvmtiRedefineClasses
307 // super-class callers:
308 // ClassFileParser - for defineClass & jvmtiRedefineClasses
309 // load_shared_class - while loading a class from shared archive
310 // resolve_instance_class_or_null:
311 // via: handle_parallel_super_load
312 // when resolving a class that has an existing placeholder with
313 // a saved superclass [i.e. a defineClass is currently in progress]
314 // if another thread is trying to resolve the class, it must do
315 // super-class checks on its own thread to catch class circularity
316 // This last call is critical in class circularity checking for cases
317 // where classloading is delegated to different threads and the
318 // classloader lock is released.
319 // Take the case: Base->Super->Base
320 // 1. If thread T1 tries to do a defineClass of class Base
321 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
322 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
323 // so it tries to load Super
324 // 3. If we load the class internally, or user classloader uses same thread
325 // loadClassFromxxx or defineClass via parseClassFile Super ...
326 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
327 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
328 // 3.4 calls resolve_super_or_fail Base
329 // 3.5 finds T1,Base -> throws class circularity
330 //OR 4. If T2 tries to resolve Super via defineClass Super ...
331 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
332 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
333 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
334 // 4.4 finds T2, Super -> throws class circularity
335 // Must be called, even if superclass is null, since this is
336 // where the placeholder entry is created which claims this
337 // thread is loading this class/classloader.
338 // Be careful when modifying this code: once you have run
339 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
340 // you need to find_and_remove it before returning.
341 // So be careful to not exit with a CHECK_ macro betweeen these calls.
342 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
343 Symbol* super_name,
344 Handle class_loader,
345 Handle protection_domain,
346 bool is_superclass,
347 TRAPS) {
348 assert(!FieldType::is_array(super_name), "invalid super class name");
349 #if INCLUDE_CDS
350 if (DumpSharedSpaces) {
351 // Special processing for handling UNREGISTERED shared classes.
352 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
353 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
354 if (k) {
355 return k;
356 }
357 }
358 #endif // INCLUDE_CDS
359
360 // Double-check, if child class is already loaded, just return super-class,interface
361 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
362 // dictionary.
363 // Make sure there's a placeholder for the *child* before resolving.
364 // Used as a claim that this thread is currently loading superclass/classloader
365 // Used here for ClassCircularity checks and also for heap verification
366 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
367 // Must check ClassCircularity before checking if super class is already loaded.
368 //
369 // We might not already have a placeholder if this child_name was
370 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
371 // the name of the class might not be known until the stream is actually
372 // parsed.
373 // Bugs 4643874, 4715493
374
375 ClassLoaderData* loader_data = class_loader_data(class_loader);
376 Dictionary* dictionary = loader_data->dictionary();
377 unsigned int d_hash = dictionary->compute_hash(child_name);
378 unsigned int p_hash = placeholders()->compute_hash(child_name);
379 int p_index = placeholders()->hash_to_index(p_hash);
380 // can't throw error holding a lock
381 bool child_already_loaded = false;
382 bool throw_circularity_error = false;
383 {
384 MutexLocker mu(SystemDictionary_lock, THREAD);
385 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
386 InstanceKlass* quicksuperk;
387 // to support // loading: if child done loading, just return superclass
388 // if super_name, & class_loader don't match:
389 // if initial define, SD update will give LinkageError
390 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
391 // so we don't throw an exception here.
392 // see: nsk redefclass014 & java.lang.instrument Instrument032
393 if ((childk != NULL ) && (is_superclass) &&
394 ((quicksuperk = childk->java_super()) != NULL) &&
395 ((quicksuperk->name() == super_name) &&
396 (quicksuperk->class_loader() == class_loader()))) {
397 return quicksuperk;
398 } else {
399 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
400 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
401 throw_circularity_error = true;
402 }
403 }
404 if (!throw_circularity_error) {
405 // Be careful not to exit resolve_super
406 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
407 }
408 }
409 if (throw_circularity_error) {
410 ResourceMark rm(THREAD);
411 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
412 }
413
414 // java.lang.Object should have been found above
415 assert(super_name != NULL, "null super class for resolving");
416 // Resolve the super class or interface, check results on return
417 InstanceKlass* superk =
418 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
419 class_loader,
420 protection_domain,
421 THREAD);
422
423 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
424 // It is no longer necessary to keep the placeholder table alive until update_dictionary
425 // or error. GC used to walk the placeholder table as strong roots.
426 // The instanceKlass is kept alive because the class loader is on the stack,
427 // which keeps the loader_data alive, as well as all instanceKlasses in
428 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
429 {
430 MutexLocker mu(SystemDictionary_lock, THREAD);
431 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
432 SystemDictionary_lock->notify_all();
433 }
434 if (HAS_PENDING_EXCEPTION || superk == NULL) {
435 // can null superk
436 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
437 assert(k == NULL || k == superk, "must be");
438 if (k == NULL) {
439 superk = NULL;
440 }
441 }
442
443 return superk;
444 }
445
446 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
447 Handle class_loader,
448 Handle protection_domain,
449 TRAPS) {
450 if(!has_checkPackageAccess()) return;
451
452 // Now we have to call back to java to check if the initating class has access
453 JavaValue result(T_VOID);
454 LogTarget(Debug, protectiondomain) lt;
455 if (lt.is_enabled()) {
456 ResourceMark rm;
457 // Print out trace information
458 LogStream ls(lt);
459 ls.print_cr("Checking package access");
460 if (class_loader() != NULL) {
461 ls.print("class loader: ");
462 class_loader()->print_value_on(&ls);
463 } else {
464 ls.print_cr("class loader: NULL");
465 }
466 if (protection_domain() != NULL) {
467 ls.print(" protection domain: ");
468 protection_domain()->print_value_on(&ls);
469 } else {
470 ls.print_cr(" protection domain: NULL");
471 }
472 ls.print(" loading: "); klass->print_value_on(&ls);
473 ls.cr();
474 }
475
476 // This handle and the class_loader handle passed in keeps this class from
477 // being unloaded through several GC points.
478 // The class_loader handle passed in is the initiating loader.
479 Handle mirror(THREAD, klass->java_mirror());
480
481 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
482 JavaCalls::call_special(&result,
483 class_loader,
484 system_loader,
485 vmSymbols::checkPackageAccess_name(),
486 vmSymbols::class_protectiondomain_signature(),
487 mirror,
488 protection_domain,
489 THREAD);
490
491 if (HAS_PENDING_EXCEPTION) {
492 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
493 } else {
494 log_debug(protectiondomain)("granted");
495 }
496
497 if (HAS_PENDING_EXCEPTION) return;
498
499 // If no exception has been thrown, we have validated the protection domain
500 // Insert the protection domain of the initiating class into the set.
501 {
502 ClassLoaderData* loader_data = class_loader_data(class_loader);
503 Dictionary* dictionary = loader_data->dictionary();
504
505 Symbol* kn = klass->name();
506 unsigned int d_hash = dictionary->compute_hash(kn);
507
508 MutexLocker mu(SystemDictionary_lock, THREAD);
509 int d_index = dictionary->hash_to_index(d_hash);
510 dictionary->add_protection_domain(d_index, d_hash, klass,
511 protection_domain, THREAD);
512 }
513 }
514
515 // We only get here if this thread finds that another thread
516 // has already claimed the placeholder token for the current operation,
517 // but that other thread either never owned or gave up the
518 // object lock
519 // Waits on SystemDictionary_lock to indicate placeholder table updated
520 // On return, caller must recheck placeholder table state
521 //
522 // We only get here if
523 // 1) custom classLoader, i.e. not bootstrap classloader
524 // 2) custom classLoader has broken the class loader objectLock
525 // so another thread got here in parallel
526 //
527 // lockObject must be held.
528 // Complicated dance due to lock ordering:
529 // Must first release the classloader object lock to
530 // allow initial definer to complete the class definition
531 // and to avoid deadlock
532 // Reclaim classloader lock object with same original recursion count
533 // Must release SystemDictionary_lock after notify, since
534 // class loader lock must be claimed before SystemDictionary_lock
535 // to prevent deadlocks
536 //
537 // The notify allows applications that did an untimed wait() on
538 // the classloader object lock to not hang.
539 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
540 assert_lock_strong(SystemDictionary_lock);
541
542 bool calledholdinglock
543 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
544 assert(calledholdinglock,"must hold lock for notify");
545 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
546 ObjectSynchronizer::notifyall(lockObject, THREAD);
547 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
548 SystemDictionary_lock->wait();
549 SystemDictionary_lock->unlock();
550 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
551 SystemDictionary_lock->lock();
552 }
553
554 // If the class in is in the placeholder table, class loading is in progress
555 // For cases where the application changes threads to load classes, it
556 // is critical to ClassCircularity detection that we try loading
557 // the superclass on the same thread internally, so we do parallel
558 // super class loading here.
559 // This also is critical in cases where the original thread gets stalled
560 // even in non-circularity situations.
561 // Note: must call resolve_super_or_fail even if null super -
562 // to force placeholder entry creation for this class for circularity detection
563 // Caller must check for pending exception
564 // Returns non-null Klass* if other thread has completed load
565 // and we are done,
566 // If return null Klass* and no pending exception, the caller must load the class
567 InstanceKlass* SystemDictionary::handle_parallel_super_load(
568 Symbol* name, Symbol* superclassname, Handle class_loader,
569 Handle protection_domain, Handle lockObject, TRAPS) {
570
571 ClassLoaderData* loader_data = class_loader_data(class_loader);
572 Dictionary* dictionary = loader_data->dictionary();
573 unsigned int d_hash = dictionary->compute_hash(name);
574 unsigned int p_hash = placeholders()->compute_hash(name);
575 int p_index = placeholders()->hash_to_index(p_hash);
576
577 // superk is not used, resolve_super called for circularity check only
578 // This code is reached in two situations. One if this thread
579 // is loading the same class twice (e.g. ClassCircularity, or
580 // java.lang.instrument).
581 // The second is if another thread started the resolve_super first
582 // and has not yet finished.
583 // In both cases the original caller will clean up the placeholder
584 // entry on error.
585 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
586 superclassname,
587 class_loader,
588 protection_domain,
589 true,
590 CHECK_NULL);
591
592 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
593 // Serial class loaders and bootstrap classloader do wait for superclass loads
594 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
595 MutexLocker mu(SystemDictionary_lock, THREAD);
596 // Check if classloading completed while we were loading superclass or waiting
597 return find_class(d_hash, name, dictionary);
598 }
599
600 // must loop to both handle other placeholder updates
601 // and spurious notifications
602 bool super_load_in_progress = true;
603 PlaceholderEntry* placeholder;
604 while (super_load_in_progress) {
605 MutexLocker mu(SystemDictionary_lock, THREAD);
606 // Check if classloading completed while we were loading superclass or waiting
607 InstanceKlass* check = find_class(d_hash, name, dictionary);
608 if (check != NULL) {
609 // Klass is already loaded, so just return it
610 return check;
611 } else {
612 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
613 if (placeholder && placeholder->super_load_in_progress() ){
614 // We only get here if the application has released the
615 // classloader lock when another thread was in the middle of loading a
616 // superclass/superinterface for this class, and now
617 // this thread is also trying to load this class.
618 // To minimize surprises, the first thread that started to
619 // load a class should be the one to complete the loading
620 // with the classfile it initially expected.
621 // This logic has the current thread wait once it has done
622 // all the superclass/superinterface loading it can, until
623 // the original thread completes the class loading or fails
624 // If it completes we will use the resulting InstanceKlass
625 // which we will find below in the systemDictionary.
626 // We also get here for parallel bootstrap classloader
627 if (class_loader.is_null()) {
628 SystemDictionary_lock->wait();
629 } else {
630 double_lock_wait(lockObject, THREAD);
631 }
632 } else {
633 // If not in SD and not in PH, other thread's load must have failed
634 super_load_in_progress = false;
635 }
636 }
637 }
638 return NULL;
639 }
640
641 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
642 assert(event != NULL, "invariant");
643 assert(k != NULL, "invariant");
644 assert(event->should_commit(), "invariant");
645 event->set_loadedClass(k);
646 event->set_definingClassLoader(k->class_loader_data());
647 event->set_initiatingClassLoader(init_cld);
648 event->commit();
649 }
650
651
652 // Be careful when modifying this code: once you have run
653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
654 // you need to find_and_remove it before returning.
655 // So be careful to not exit with a CHECK_ macro betweeen these calls.
656 //
657 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
658 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
659 Handle class_loader,
660 Handle protection_domain,
661 TRAPS) {
662 assert(name != NULL && !FieldType::is_array(name) &&
663 !FieldType::is_obj(name), "invalid class name");
664
665 EventClassLoad class_load_start_event;
666
667 HandleMark hm(THREAD);
668
669 // Fix for 4474172; see evaluation for more details
670 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
671 ClassLoaderData* loader_data = register_loader(class_loader);
672 Dictionary* dictionary = loader_data->dictionary();
673 unsigned int d_hash = dictionary->compute_hash(name);
674
675 // Do lookup to see if class already exist and the protection domain
676 // has the right access
677 // This call uses find which checks protection domain already matches
678 // All subsequent calls use find_class, and set has_loaded_class so that
679 // before we return a result we call out to java to check for valid protection domain
680 // to allow returning the Klass* and add it to the pd_set if it is valid
681 {
682 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
683 if (probe != NULL) return probe;
684 }
685
686 // Non-bootstrap class loaders will call out to class loader and
687 // define via jvm/jni_DefineClass which will acquire the
688 // class loader object lock to protect against multiple threads
689 // defining the class in parallel by accident.
690 // This lock must be acquired here so the waiter will find
691 // any successful result in the SystemDictionary and not attempt
692 // the define.
693 // ParallelCapable Classloaders and the bootstrap classloader
694 // do not acquire lock here.
695 bool DoObjectLock = true;
696 if (is_parallelCapable(class_loader)) {
697 DoObjectLock = false;
698 }
699
700 unsigned int p_hash = placeholders()->compute_hash(name);
701 int p_index = placeholders()->hash_to_index(p_hash);
702
703 // Class is not in SystemDictionary so we have to do loading.
704 // Make sure we are synchronized on the class loader before we proceed
705 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
706 check_loader_lock_contention(lockObject, THREAD);
707 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
708
709 // Check again (after locking) if class already exist in SystemDictionary
710 bool class_has_been_loaded = false;
711 bool super_load_in_progress = false;
712 bool havesupername = false;
713 InstanceKlass* k = NULL;
714 PlaceholderEntry* placeholder;
715 Symbol* superclassname = NULL;
716
717 assert(THREAD->can_call_java(),
718 "can not load classes with compiler thread: class=%s, classloader=%s",
719 name->as_C_string(),
720 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
721 {
722 MutexLocker mu(SystemDictionary_lock, THREAD);
723 InstanceKlass* check = find_class(d_hash, name, dictionary);
724 if (check != NULL) {
725 // InstanceKlass is already loaded, so just return it
726 class_has_been_loaded = true;
727 k = check;
728 } else {
729 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
730 if (placeholder && placeholder->super_load_in_progress()) {
731 super_load_in_progress = true;
732 if (placeholder->havesupername() == true) {
733 superclassname = placeholder->supername();
734 havesupername = true;
735 }
736 }
737 }
738 }
739
740 // If the class is in the placeholder table, class loading is in progress
741 if (super_load_in_progress && havesupername==true) {
742 k = handle_parallel_super_load(name,
743 superclassname,
744 class_loader,
745 protection_domain,
746 lockObject, THREAD);
747 if (HAS_PENDING_EXCEPTION) {
748 return NULL;
749 }
750 if (k != NULL) {
751 class_has_been_loaded = true;
752 }
753 }
754
755 bool throw_circularity_error = false;
756 if (!class_has_been_loaded) {
757 bool load_instance_added = false;
758
759 // add placeholder entry to record loading instance class
760 // Five cases:
761 // All cases need to prevent modifying bootclasssearchpath
762 // in parallel with a classload of same classname
763 // Redefineclasses uses existence of the placeholder for the duration
764 // of the class load to prevent concurrent redefinition of not completely
765 // defined classes.
766 // case 1. traditional classloaders that rely on the classloader object lock
767 // - no other need for LOAD_INSTANCE
768 // case 2. traditional classloaders that break the classloader object lock
769 // as a deadlock workaround. Detection of this case requires that
770 // this check is done while holding the classloader object lock,
771 // and that lock is still held when calling classloader's loadClass.
772 // For these classloaders, we ensure that the first requestor
773 // completes the load and other requestors wait for completion.
774 // case 3. Bootstrap classloader - don't own objectLocker
775 // This classloader supports parallelism at the classloader level,
776 // but only allows a single load of a class/classloader pair.
777 // No performance benefit and no deadlock issues.
778 // case 4. parallelCapable user level classloaders - without objectLocker
779 // Allow parallel classloading of a class/classloader pair
780
781 {
782 MutexLocker mu(SystemDictionary_lock, THREAD);
783 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
784 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
785 if (oldprobe) {
786 // only need check_seen_thread once, not on each loop
787 // 6341374 java/lang/Instrument with -Xcomp
788 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
789 throw_circularity_error = true;
790 } else {
791 // case 1: traditional: should never see load_in_progress.
792 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
793
794 // case 3: bootstrap classloader: prevent futile classloading,
795 // wait on first requestor
796 if (class_loader.is_null()) {
797 SystemDictionary_lock->wait();
798 } else {
799 // case 2: traditional with broken classloader lock. wait on first
800 // requestor.
801 double_lock_wait(lockObject, THREAD);
802 }
803 // Check if classloading completed while we were waiting
804 InstanceKlass* check = find_class(d_hash, name, dictionary);
805 if (check != NULL) {
806 // Klass is already loaded, so just return it
807 k = check;
808 class_has_been_loaded = true;
809 }
810 // check if other thread failed to load and cleaned up
811 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
812 }
813 }
814 }
815 }
816 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
817 // case 4: parallelCapable: allow competing threads to try
818 // LOAD_INSTANCE in parallel
819
820 if (!throw_circularity_error && !class_has_been_loaded) {
821 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
822 load_instance_added = true;
823 // For class loaders that do not acquire the classloader object lock,
824 // if they did not catch another thread holding LOAD_INSTANCE,
825 // need a check analogous to the acquire ObjectLocker/find_class
826 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
827 // one final check if the load has already completed
828 // class loaders holding the ObjectLock shouldn't find the class here
829 InstanceKlass* check = find_class(d_hash, name, dictionary);
830 if (check != NULL) {
831 // Klass is already loaded, so return it after checking/adding protection domain
832 k = check;
833 class_has_been_loaded = true;
834 }
835 }
836 }
837
838 // must throw error outside of owning lock
839 if (throw_circularity_error) {
840 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
841 ResourceMark rm(THREAD);
842 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
843 }
844
845 if (!class_has_been_loaded) {
846
847 // Do actual loading
848 k = load_instance_class(name, class_loader, THREAD);
849
850 // If everything was OK (no exceptions, no null return value), and
851 // class_loader is NOT the defining loader, do a little more bookkeeping.
852 if (!HAS_PENDING_EXCEPTION && k != NULL &&
853 k->class_loader() != class_loader()) {
854
855 check_constraints(d_hash, k, class_loader, false, THREAD);
856
857 // Need to check for a PENDING_EXCEPTION again; check_constraints
858 // can throw but we may have to remove entry from the placeholder table below.
859 if (!HAS_PENDING_EXCEPTION) {
860 // Record dependency for non-parent delegation.
861 // This recording keeps the defining class loader of the klass (k) found
862 // from being unloaded while the initiating class loader is loaded
863 // even if the reference to the defining class loader is dropped
864 // before references to the initiating class loader.
865 loader_data->record_dependency(k);
866
867 { // Grabbing the Compile_lock prevents systemDictionary updates
868 // during compilations.
869 MutexLocker mu(Compile_lock, THREAD);
870 update_dictionary(d_hash, p_index, p_hash,
871 k, class_loader, THREAD);
872 }
873
874 if (JvmtiExport::should_post_class_load()) {
875 Thread *thread = THREAD;
876 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
877 JvmtiExport::post_class_load((JavaThread *) thread, k);
878 }
879 }
880 }
881 } // load_instance_class
882
883 if (load_instance_added == true) {
884 // clean up placeholder entries for LOAD_INSTANCE success or error
885 // This brackets the SystemDictionary updates for both defining
886 // and initiating loaders
887 MutexLocker mu(SystemDictionary_lock, THREAD);
888 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
889 SystemDictionary_lock->notify_all();
890 }
891 }
892
893 if (HAS_PENDING_EXCEPTION || k == NULL) {
894 return NULL;
895 }
896 if (class_load_start_event.should_commit()) {
897 post_class_load_event(&class_load_start_event, k, loader_data);
898 }
899 #ifdef ASSERT
900 {
901 ClassLoaderData* loader_data = k->class_loader_data();
902 MutexLocker mu(SystemDictionary_lock, THREAD);
903 InstanceKlass* kk = find_class(name, loader_data);
904 assert(kk == k, "should be present in dictionary");
905 }
906 #endif
907
908 // return if the protection domain in NULL
909 if (protection_domain() == NULL) return k;
910
911 // Check the protection domain has the right access
912 if (dictionary->is_valid_protection_domain(d_hash, name,
913 protection_domain)) {
914 return k;
915 }
916
917 // Verify protection domain. If it fails an exception is thrown
918 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
919
920 return k;
921 }
922
923
924 // This routine does not lock the system dictionary.
925 //
926 // Since readers don't hold a lock, we must make sure that system
927 // dictionary entries are only removed at a safepoint (when only one
928 // thread is running), and are added to in a safe way (all links must
929 // be updated in an MT-safe manner).
930 //
931 // Callers should be aware that an entry could be added just after
932 // _dictionary->bucket(index) is read here, so the caller will not see
933 // the new entry.
934
935 Klass* SystemDictionary::find(Symbol* class_name,
936 Handle class_loader,
937 Handle protection_domain,
938 TRAPS) {
939
940 // The result of this call should be consistent with the result
941 // of the call to resolve_instance_class_or_null().
942 // See evaluation 6790209 and 4474172 for more details.
943 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
944 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
945
946 if (loader_data == NULL) {
947 // If the ClassLoaderData has not been setup,
948 // then the class loader has no entries in the dictionary.
949 return NULL;
950 }
951
952 Dictionary* dictionary = loader_data->dictionary();
953 unsigned int d_hash = dictionary->compute_hash(class_name);
954 return dictionary->find(d_hash, class_name,
955 protection_domain);
956 }
957
958
959 // Look for a loaded instance or array klass by name. Do not do any loading.
960 // return NULL in case of error.
961 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
962 Handle class_loader,
963 Handle protection_domain,
964 TRAPS) {
965 Klass* k = NULL;
966 assert(class_name != NULL, "class name must be non NULL");
967
968 if (FieldType::is_array(class_name)) {
969 // The name refers to an array. Parse the name.
970 // dimension and object_key in FieldArrayInfo are assigned as a
971 // side-effect of this call
972 FieldArrayInfo fd;
973 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
974 if (t != T_OBJECT) {
975 k = Universe::typeArrayKlassObj(t);
976 } else {
977 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
978 }
979 if (k != NULL) {
980 k = k->array_klass_or_null(fd.dimension());
981 }
982 } else {
983 k = find(class_name, class_loader, protection_domain, THREAD);
984 }
985 return k;
986 }
987
988 // Note: this method is much like resolve_from_stream, but
989 // does not publish the classes via the SystemDictionary.
990 // Handles unsafe_DefineAnonymousClass and redefineclasses
991 // RedefinedClasses do not add to the class hierarchy
992 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
993 Handle class_loader,
994 Handle protection_domain,
995 ClassFileStream* st,
996 const InstanceKlass* unsafe_anonymous_host,
997 GrowableArray<Handle>* cp_patches,
998 TRAPS) {
999
1000 EventClassLoad class_load_start_event;
1001
1002 ClassLoaderData* loader_data;
1003 if (unsafe_anonymous_host != NULL) {
1004 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1005 // as the unsafe_anonymous_host
1006 guarantee(unsafe_anonymous_host->class_loader() == class_loader(), "should be the same");
1007 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1008 } else {
1009 loader_data = ClassLoaderData::class_loader_data(class_loader());
1010 }
1011
1012 assert(st != NULL, "invariant");
1013 assert(st->need_verify(), "invariant");
1014
1015 // Parse stream and create a klass.
1016 // Note that we do this even though this klass might
1017 // already be present in the SystemDictionary, otherwise we would not
1018 // throw potential ClassFormatErrors.
1019
1020 InstanceKlass* k = KlassFactory::create_from_stream(st,
1021 class_name,
1022 loader_data,
1023 protection_domain,
1024 unsafe_anonymous_host,
1025 cp_patches,
1026 CHECK_NULL);
1027
1028 if (unsafe_anonymous_host != NULL && k != NULL) {
1029 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1030 // so that they can be unloaded when the mirror is no longer referenced.
1031 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1032
1033 {
1034 MutexLocker mu_r(Compile_lock, THREAD);
1035
1036 // Add to class hierarchy, initialize vtables, and do possible
1037 // deoptimizations.
1038 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1039 // But, do not add to dictionary.
1040 }
1041
1042 // Rewrite and patch constant pool here.
1043 k->link_class(CHECK_NULL);
1044 if (cp_patches != NULL) {
1045 k->constants()->patch_resolved_references(cp_patches);
1046 }
1047
1048 // If it's anonymous, initialize it now, since nobody else will.
1049 k->eager_initialize(CHECK_NULL);
1050
1051 // notify jvmti
1052 if (JvmtiExport::should_post_class_load()) {
1053 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1054 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1055 }
1056 if (class_load_start_event.should_commit()) {
1057 post_class_load_event(&class_load_start_event, k, loader_data);
1058 }
1059 }
1060 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1061 "cp_patches only found with unsafe_anonymous_host");
1062
1063 return k;
1064 }
1065
1066 // Add a klass to the system from a stream (called by jni_DefineClass and
1067 // JVM_DefineClass).
1068 // Note: class_name can be NULL. In that case we do not know the name of
1069 // the class until we have parsed the stream.
1070
1071 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1072 Handle class_loader,
1073 Handle protection_domain,
1074 ClassFileStream* st,
1075 TRAPS) {
1076
1077 HandleMark hm(THREAD);
1078
1079 // Classloaders that support parallelism, e.g. bootstrap classloader,
1080 // do not acquire lock here
1081 bool DoObjectLock = true;
1082 if (is_parallelCapable(class_loader)) {
1083 DoObjectLock = false;
1084 }
1085
1086 ClassLoaderData* loader_data = register_loader(class_loader);
1087
1088 // Make sure we are synchronized on the class loader before we proceed
1089 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1090 check_loader_lock_contention(lockObject, THREAD);
1091 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1092
1093 assert(st != NULL, "invariant");
1094
1095 // Parse the stream and create a klass.
1096 // Note that we do this even though this klass might
1097 // already be present in the SystemDictionary, otherwise we would not
1098 // throw potential ClassFormatErrors.
1099 InstanceKlass* k = NULL;
1100
1101 #if INCLUDE_CDS
1102 if (!DumpSharedSpaces) {
1103 k = SystemDictionaryShared::lookup_from_stream(class_name,
1104 class_loader,
1105 protection_domain,
1106 st,
1107 CHECK_NULL);
1108 }
1109 #endif
1110
1111 if (k == NULL) {
1112 if (st->buffer() == NULL) {
1113 return NULL;
1114 }
1115 k = KlassFactory::create_from_stream(st,
1116 class_name,
1117 loader_data,
1118 protection_domain,
1119 NULL, // unsafe_anonymous_host
1120 NULL, // cp_patches
1121 CHECK_NULL);
1122 }
1123
1124 assert(k != NULL, "no klass created");
1125 Symbol* h_name = k->name();
1126 assert(class_name == NULL || class_name == h_name, "name mismatch");
1127
1128 // Add class just loaded
1129 // If a class loader supports parallel classloading handle parallel define requests
1130 // find_or_define_instance_class may return a different InstanceKlass
1131 if (is_parallelCapable(class_loader)) {
1132 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1133 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1134 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1135 assert(defined_k != NULL, "Should have a klass if there's no exception");
1136 loader_data->add_to_deallocate_list(k);
1137 k = defined_k;
1138 }
1139 } else {
1140 define_instance_class(k, THREAD);
1141 }
1142
1143 // If defining the class throws an exception register 'k' for cleanup.
1144 if (HAS_PENDING_EXCEPTION) {
1145 assert(k != NULL, "Must have an instance klass here!");
1146 loader_data->add_to_deallocate_list(k);
1147 return NULL;
1148 }
1149
1150 // Make sure we have an entry in the SystemDictionary on success
1151 debug_only( {
1152 MutexLocker mu(SystemDictionary_lock, THREAD);
1153
1154 Klass* check = find_class(h_name, k->class_loader_data());
1155 assert(check == k, "should be present in the dictionary");
1156 } );
1157
1158 return k;
1159 }
1160
1161 #if INCLUDE_CDS
1162 // Load a class for boot loader from the shared spaces. This also
1163 // forces the super class and all interfaces to be loaded.
1164 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1165 TRAPS) {
1166 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1167 if (ik != NULL && ik->is_shared_boot_class()) {
1168 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1169 }
1170 return NULL;
1171 }
1172
1173 // Check if a shared class can be loaded by the specific classloader:
1174 //
1175 // NULL classloader:
1176 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1177 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1178 // be defined in an unnamed module.
1179 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1180 InstanceKlass* ik,
1181 Handle class_loader, TRAPS) {
1182 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1183 "Cannot use sharing if java.base is patched");
1184 ResourceMark rm;
1185 int path_index = ik->shared_classpath_index();
1186 ClassLoaderData* loader_data = class_loader_data(class_loader);
1187 if (path_index < 0) {
1188 // path_index < 0 indicates that the class is intended for a custom loader
1189 // and should not be loaded by boot/platform/app loaders
1190 if (loader_data->is_builtin_class_loader_data()) {
1191 return false;
1192 } else {
1193 return true;
1194 }
1195 }
1196 SharedClassPathEntry* ent =
1197 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1198 if (!Universe::is_module_initialized()) {
1199 assert(ent != NULL && ent->is_modules_image(),
1200 "Loading non-bootstrap classes before the module system is initialized");
1201 assert(class_loader.is_null(), "sanity");
1202 return true;
1203 }
1204 // Get the pkg_entry from the classloader
1205 TempNewSymbol pkg_name = NULL;
1206 PackageEntry* pkg_entry = NULL;
1207 ModuleEntry* mod_entry = NULL;
1208 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1209 if (pkg_name != NULL) {
1210 if (loader_data != NULL) {
1211 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1212 }
1213 if (pkg_entry != NULL) {
1214 mod_entry = pkg_entry->module();
1215 }
1216 }
1217
1218 // If the archived class is from a module that has been patched at runtime,
1219 // the class cannot be loaded from the archive.
1220 if (mod_entry != NULL && mod_entry->is_patched()) {
1221 return false;
1222 }
1223
1224 if (class_loader.is_null()) {
1225 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1226 // The NULL classloader can load archived class originated from the
1227 // "modules" jimage and the -Xbootclasspath/a. For class from the
1228 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1229 // by the NULL classloader.
1230 if (mod_entry != NULL) {
1231 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1232 // ModuleEntry's location agrees with the archived class' origination.
1233 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1234 return true; // Module class from the "module" jimage
1235 }
1236 }
1237
1238 // If the archived class is not from the "module" jimage, the class can be
1239 // loaded by the NULL classloader if
1240 //
1241 // 1. the class is from the unamed package
1242 // 2. or, the class is not from a module defined in the NULL classloader
1243 // 3. or, the class is from an unamed module
1244 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1245 // the class is from the -Xbootclasspath/a
1246 if (pkg_name == NULL ||
1247 pkg_entry == NULL ||
1248 pkg_entry->in_unnamed_module()) {
1249 assert(mod_entry == NULL ||
1250 mod_entry == loader_data->unnamed_module(),
1251 "the unnamed module is not defined in the classloader");
1252 return true;
1253 }
1254 }
1255 return false;
1256 } else {
1257 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1258 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1259 return res;
1260 }
1261 }
1262
1263 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1264 Handle class_loader,
1265 Handle protection_domain,
1266 const ClassFileStream *cfs,
1267 TRAPS) {
1268 assert(ik != NULL, "sanity");
1269 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1270 Symbol* class_name = ik->name();
1271
1272 bool visible = is_shared_class_visible(
1273 class_name, ik, class_loader, CHECK_NULL);
1274 if (!visible) {
1275 return NULL;
1276 }
1277
1278 // Resolve the superclass and interfaces. They must be the same
1279 // as in dump time, because the layout of <ik> depends on
1280 // the specific layout of ik->super() and ik->local_interfaces().
1281 //
1282 // If unexpected superclass or interfaces are found, we cannot
1283 // load <ik> from the shared archive.
1284
1285 if (ik->super() != NULL) {
1286 Symbol* cn = ik->super()->name();
1287 Klass *s = resolve_super_or_fail(class_name, cn,
1288 class_loader, protection_domain, true, CHECK_NULL);
1289 if (s != ik->super()) {
1290 // The dynamically resolved super class is not the same as the one we used during dump time,
1291 // so we cannot use ik.
1292 return NULL;
1293 } else {
1294 assert(s->is_shared(), "must be");
1295 }
1296 }
1297
1298 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1299 int num_interfaces = interfaces->length();
1300 for (int index = 0; index < num_interfaces; index++) {
1301 InstanceKlass* k = interfaces->at(index);
1302 Symbol* name = k->name();
1303 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1304 if (k != i) {
1305 // The dynamically resolved interface class is not the same as the one we used during dump time,
1306 // so we cannot use ik.
1307 return NULL;
1308 } else {
1309 assert(i->is_shared(), "must be");
1310 }
1311 }
1312
1313 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1314 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1315 if (new_ik != NULL) {
1316 // The class is changed by CFLH. Return the new class. The shared class is
1317 // not used.
1318 return new_ik;
1319 }
1320
1321 // Adjust methods to recover missing data. They need addresses for
1322 // interpreter entry points and their default native method address
1323 // must be reset.
1324
1325 // Updating methods must be done under a lock so multiple
1326 // threads don't update these in parallel
1327 //
1328 // Shared classes are all currently loaded by either the bootstrap or
1329 // internal parallel class loaders, so this will never cause a deadlock
1330 // on a custom class loader lock.
1331
1332 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1333 {
1334 HandleMark hm(THREAD);
1335 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1336 check_loader_lock_contention(lockObject, THREAD);
1337 ObjectLocker ol(lockObject, THREAD, true);
1338 // prohibited package check assumes all classes loaded from archive call
1339 // restore_unshareable_info which calls ik->set_package()
1340 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1341 }
1342
1343 ik->print_class_load_logging(loader_data, NULL, NULL);
1344
1345 // For boot loader, ensure that GetSystemPackage knows that a class in this
1346 // package was loaded.
1347 if (class_loader.is_null()) {
1348 int path_index = ik->shared_classpath_index();
1349 ResourceMark rm;
1350 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1351 }
1352
1353 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1354 // Only dump the classes that can be stored into CDS archive
1355 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1356 ResourceMark rm(THREAD);
1357 classlist_file->print_cr("%s", ik->name()->as_C_string());
1358 classlist_file->flush();
1359 }
1360 }
1361
1362 // notify a class loaded from shared object
1363 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1364
1365 ik->set_has_passed_fingerprint_check(false);
1366 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1367 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1368 uint64_t cds_fp = ik->get_stored_fingerprint();
1369 if (aot_fp != 0 && aot_fp == cds_fp) {
1370 // This class matches with a class saved in an AOT library
1371 ik->set_has_passed_fingerprint_check(true);
1372 } else {
1373 ResourceMark rm;
1374 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1375 }
1376 }
1377
1378 return ik;
1379 }
1380 #endif // INCLUDE_CDS
1381
1382 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1383
1384 if (class_loader.is_null()) {
1385 ResourceMark rm;
1386 PackageEntry* pkg_entry = NULL;
1387 bool search_only_bootloader_append = false;
1388 ClassLoaderData *loader_data = class_loader_data(class_loader);
1389
1390 // Find the package in the boot loader's package entry table.
1391 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1392 if (pkg_name != NULL) {
1393 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1394 }
1395
1396 // Prior to attempting to load the class, enforce the boot loader's
1397 // visibility boundaries.
1398 if (!Universe::is_module_initialized()) {
1399 // During bootstrapping, prior to module initialization, any
1400 // class attempting to be loaded must be checked against the
1401 // java.base packages in the boot loader's PackageEntryTable.
1402 // No class outside of java.base is allowed to be loaded during
1403 // this bootstrapping window.
1404 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1405 // Class is either in the unnamed package or in
1406 // a named package within the unnamed module. Either
1407 // case is outside of java.base, do not attempt to
1408 // load the class post java.base definition. If
1409 // java.base has not been defined, let the class load
1410 // and its package will be checked later by
1411 // ModuleEntryTable::verify_javabase_packages.
1412 if (ModuleEntryTable::javabase_defined()) {
1413 return NULL;
1414 }
1415 } else {
1416 // Check that the class' package is defined within java.base.
1417 ModuleEntry* mod_entry = pkg_entry->module();
1418 Symbol* mod_entry_name = mod_entry->name();
1419 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1420 return NULL;
1421 }
1422 }
1423 } else {
1424 // After the module system has been initialized, check if the class'
1425 // package is in a module defined to the boot loader.
1426 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1427 // Class is either in the unnamed package, in a named package
1428 // within a module not defined to the boot loader or in a
1429 // a named package within the unnamed module. In all cases,
1430 // limit visibility to search for the class only in the boot
1431 // loader's append path.
1432 if (!ClassLoader::has_bootclasspath_append()) {
1433 // If there is no bootclasspath append entry, no need to continue
1434 // searching.
1435 return NULL;
1436 }
1437 search_only_bootloader_append = true;
1438 }
1439 }
1440
1441 // Prior to bootstrapping's module initialization, never load a class outside
1442 // of the boot loader's module path
1443 assert(Universe::is_module_initialized() ||
1444 !search_only_bootloader_append,
1445 "Attempt to load a class outside of boot loader's module path");
1446
1447 // Search for classes in the CDS archive.
1448 InstanceKlass* k = NULL;
1449 {
1450 #if INCLUDE_CDS
1451 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1452 k = load_shared_boot_class(class_name, THREAD);
1453 #endif
1454 }
1455
1456 if (k == NULL) {
1457 // Use VM class loader
1458 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1459 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1460 }
1461
1462 // find_or_define_instance_class may return a different InstanceKlass
1463 if (k != NULL) {
1464 InstanceKlass* defined_k =
1465 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1466 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1467 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1468 assert(defined_k != NULL, "Should have a klass if there's no exception");
1469 loader_data->add_to_deallocate_list(k);
1470 k = defined_k;
1471 } else if (HAS_PENDING_EXCEPTION) {
1472 loader_data->add_to_deallocate_list(k);
1473 return NULL;
1474 }
1475 }
1476 return k;
1477 } else {
1478 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1479 ResourceMark rm(THREAD);
1480
1481 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1482 JavaThread* jt = (JavaThread*) THREAD;
1483
1484 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1485 ClassLoader::perf_app_classload_selftime(),
1486 ClassLoader::perf_app_classload_count(),
1487 jt->get_thread_stat()->perf_recursion_counts_addr(),
1488 jt->get_thread_stat()->perf_timers_addr(),
1489 PerfClassTraceTime::CLASS_LOAD);
1490
1491 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1492 // Translate to external class name format, i.e., convert '/' chars to '.'
1493 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1494
1495 JavaValue result(T_OBJECT);
1496
1497 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1498
1499 // Call public unsynchronized loadClass(String) directly for all class loaders.
1500 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1501 // acquire a class-name based lock rather than the class loader object lock.
1502 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1503 JavaCalls::call_virtual(&result,
1504 class_loader,
1505 spec_klass,
1506 vmSymbols::loadClass_name(),
1507 vmSymbols::string_class_signature(),
1508 string,
1509 CHECK_NULL);
1510
1511 assert(result.get_type() == T_OBJECT, "just checking");
1512 oop obj = (oop) result.get_jobject();
1513
1514 // Primitive classes return null since forName() can not be
1515 // used to obtain any of the Class objects representing primitives or void
1516 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1517 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1518 // For user defined Java class loaders, check that the name returned is
1519 // the same as that requested. This check is done for the bootstrap
1520 // loader when parsing the class file.
1521 if (class_name == k->name()) {
1522 return k;
1523 }
1524 }
1525 // Class is not found or has the wrong name, return NULL
1526 return NULL;
1527 }
1528 }
1529
1530 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1531 EventClassDefine event;
1532 if (event.should_commit()) {
1533 event.set_definedClass(k);
1534 event.set_definingClassLoader(def_cld);
1535 event.commit();
1536 }
1537 }
1538
1539 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1540
1541 HandleMark hm(THREAD);
1542 ClassLoaderData* loader_data = k->class_loader_data();
1543 Handle class_loader_h(THREAD, loader_data->class_loader());
1544
1545 // for bootstrap and other parallel classloaders don't acquire lock,
1546 // use placeholder token
1547 // If a parallelCapable class loader calls define_instance_class instead of
1548 // find_or_define_instance_class to get here, we have a timing
1549 // hole with systemDictionary updates and check_constraints
1550 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1551 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1552 compute_loader_lock_object(class_loader_h, THREAD)),
1553 "define called without lock");
1554 }
1555
1556 // Check class-loading constraints. Throw exception if violation is detected.
1557 // Grabs and releases SystemDictionary_lock
1558 // The check_constraints/find_class call and update_dictionary sequence
1559 // must be "atomic" for a specific class/classloader pair so we never
1560 // define two different instanceKlasses for that class/classloader pair.
1561 // Existing classloaders will call define_instance_class with the
1562 // classloader lock held
1563 // Parallel classloaders will call find_or_define_instance_class
1564 // which will require a token to perform the define class
1565 Symbol* name_h = k->name();
1566 Dictionary* dictionary = loader_data->dictionary();
1567 unsigned int d_hash = dictionary->compute_hash(name_h);
1568 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1569
1570 // Register class just loaded with class loader (placed in Vector)
1571 // Note we do this before updating the dictionary, as this can
1572 // fail with an OutOfMemoryError (if it does, we will *not* put this
1573 // class in the dictionary and will not update the class hierarchy).
1574 // JVMTI FollowReferences needs to find the classes this way.
1575 if (k->class_loader() != NULL) {
1576 methodHandle m(THREAD, Universe::loader_addClass_method());
1577 JavaValue result(T_VOID);
1578 JavaCallArguments args(class_loader_h);
1579 args.push_oop(Handle(THREAD, k->java_mirror()));
1580 JavaCalls::call(&result, m, &args, CHECK);
1581 }
1582
1583 // Add the new class. We need recompile lock during update of CHA.
1584 {
1585 unsigned int p_hash = placeholders()->compute_hash(name_h);
1586 int p_index = placeholders()->hash_to_index(p_hash);
1587
1588 MutexLocker mu_r(Compile_lock, THREAD);
1589
1590 // Add to class hierarchy, initialize vtables, and do possible
1591 // deoptimizations.
1592 add_to_hierarchy(k, CHECK); // No exception, but can block
1593
1594 // Add to systemDictionary - so other classes can see it.
1595 // Grabs and releases SystemDictionary_lock
1596 update_dictionary(d_hash, p_index, p_hash,
1597 k, class_loader_h, THREAD);
1598 }
1599 k->eager_initialize(THREAD);
1600
1601 // notify jvmti
1602 if (JvmtiExport::should_post_class_load()) {
1603 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1604 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1605
1606 }
1607 post_class_define_event(k, loader_data);
1608 }
1609
1610 // Support parallel classloading
1611 // All parallel class loaders, including bootstrap classloader
1612 // lock a placeholder entry for this class/class_loader pair
1613 // to allow parallel defines of different classes for this class loader
1614 // With AllowParallelDefine flag==true, in case they do not synchronize around
1615 // FindLoadedClass/DefineClass, calls, we check for parallel
1616 // loading for them, wait if a defineClass is in progress
1617 // and return the initial requestor's results
1618 // This flag does not apply to the bootstrap classloader.
1619 // With AllowParallelDefine flag==false, call through to define_instance_class
1620 // which will throw LinkageError: duplicate class definition.
1621 // False is the requested default.
1622 // For better performance, the class loaders should synchronize
1623 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1624 // potentially waste time reading and parsing the bytestream.
1625 // Note: VM callers should ensure consistency of k/class_name,class_loader
1626 // Be careful when modifying this code: once you have run
1627 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1628 // you need to find_and_remove it before returning.
1629 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1630 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1631 InstanceKlass* k, TRAPS) {
1632
1633 Symbol* name_h = k->name(); // passed in class_name may be null
1634 ClassLoaderData* loader_data = class_loader_data(class_loader);
1635 Dictionary* dictionary = loader_data->dictionary();
1636
1637 unsigned int d_hash = dictionary->compute_hash(name_h);
1638
1639 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1640 unsigned int p_hash = placeholders()->compute_hash(name_h);
1641 int p_index = placeholders()->hash_to_index(p_hash);
1642 PlaceholderEntry* probe;
1643
1644 {
1645 MutexLocker mu(SystemDictionary_lock, THREAD);
1646 // First check if class already defined
1647 if (is_parallelDefine(class_loader)) {
1648 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1649 if (check != NULL) {
1650 return check;
1651 }
1652 }
1653
1654 // Acquire define token for this class/classloader
1655 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1656 // Wait if another thread defining in parallel
1657 // All threads wait - even those that will throw duplicate class: otherwise
1658 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1659 // if other thread has not finished updating dictionary
1660 while (probe->definer() != NULL) {
1661 SystemDictionary_lock->wait();
1662 }
1663 // Only special cases allow parallel defines and can use other thread's results
1664 // Other cases fall through, and may run into duplicate defines
1665 // caught by finding an entry in the SystemDictionary
1666 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1667 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1668 SystemDictionary_lock->notify_all();
1669 #ifdef ASSERT
1670 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1671 assert(check != NULL, "definer missed recording success");
1672 #endif
1673 return probe->instance_klass();
1674 } else {
1675 // This thread will define the class (even if earlier thread tried and had an error)
1676 probe->set_definer(THREAD);
1677 }
1678 }
1679
1680 define_instance_class(k, THREAD);
1681
1682 Handle linkage_exception = Handle(); // null handle
1683
1684 // definer must notify any waiting threads
1685 {
1686 MutexLocker mu(SystemDictionary_lock, THREAD);
1687 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1688 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1689 if (probe != NULL) {
1690 if (HAS_PENDING_EXCEPTION) {
1691 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1692 CLEAR_PENDING_EXCEPTION;
1693 } else {
1694 probe->set_instance_klass(k);
1695 }
1696 probe->set_definer(NULL);
1697 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1698 SystemDictionary_lock->notify_all();
1699 }
1700 }
1701
1702 // Can't throw exception while holding lock due to rank ordering
1703 if (linkage_exception() != NULL) {
1704 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1705 }
1706
1707 return k;
1708 }
1709
1710 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1711 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1712 if (class_loader.is_null()) {
1713 return Handle(THREAD, _system_loader_lock_obj);
1714 } else {
1715 return class_loader;
1716 }
1717 }
1718
1719 // This method is added to check how often we have to wait to grab loader
1720 // lock. The results are being recorded in the performance counters defined in
1721 // ClassLoader::_sync_systemLoaderLockContentionRate and
1722 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1723 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1724 if (!UsePerfData) {
1725 return;
1726 }
1727
1728 assert(!loader_lock.is_null(), "NULL lock object");
1729
1730 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1731 == ObjectSynchronizer::owner_other) {
1732 // contention will likely happen, so increment the corresponding
1733 // contention counter.
1734 if (loader_lock() == _system_loader_lock_obj) {
1735 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1736 } else {
1737 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1738 }
1739 }
1740 }
1741
1742 // ----------------------------------------------------------------------------
1743 // Lookup
1744
1745 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1746 Symbol* class_name,
1747 Dictionary* dictionary) {
1748 assert_locked_or_safepoint(SystemDictionary_lock);
1749 int index = dictionary->hash_to_index(hash);
1750 return dictionary->find_class(index, hash, class_name);
1751 }
1752
1753
1754 // Basic find on classes in the midst of being loaded
1755 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1756 ClassLoaderData* loader_data) {
1757 assert_locked_or_safepoint(SystemDictionary_lock);
1758 unsigned int p_hash = placeholders()->compute_hash(class_name);
1759 int p_index = placeholders()->hash_to_index(p_hash);
1760 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1761 }
1762
1763
1764 // Used for assertions and verification only
1765 // Precalculating the hash and index is an optimization because there are many lookups
1766 // before adding the class.
1767 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1768 assert_locked_or_safepoint(SystemDictionary_lock);
1769 #ifndef ASSERT
1770 guarantee(VerifyBeforeGC ||
1771 VerifyDuringGC ||
1772 VerifyBeforeExit ||
1773 VerifyDuringStartup ||
1774 VerifyAfterGC, "too expensive");
1775 #endif
1776
1777 Dictionary* dictionary = loader_data->dictionary();
1778 unsigned int d_hash = dictionary->compute_hash(class_name);
1779 return find_class(d_hash, class_name, dictionary);
1780 }
1781
1782
1783 // ----------------------------------------------------------------------------
1784 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1785 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1786 // before a new class is used.
1787
1788 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1789 assert(k != NULL, "just checking");
1790 assert_locked_or_safepoint(Compile_lock);
1791
1792 k->set_init_state(InstanceKlass::loaded);
1793 // make sure init_state store is already done.
1794 // The compiler reads the hierarchy outside of the Compile_lock.
1795 // Access ordering is used to add to hierarchy.
1796
1797 // Link into hierachy.
1798 k->append_to_sibling_list(); // add to superklass/sibling list
1799 k->process_interfaces(THREAD); // handle all "implements" declarations
1800
1801 // Now flush all code that depended on old class hierarchy.
1802 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1803 CodeCache::flush_dependents_on(k);
1804 }
1805
1806 // ----------------------------------------------------------------------------
1807 // GC support
1808
1809 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1810 // Note: anonymous classes are not in the SD.
1811 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1812
1813 bool unloading_occurred;
1814 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1815 {
1816 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1817 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1818 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1819 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1820 if (unloading_occurred) {
1821 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1822 JFR_ONLY(Jfr::on_unloading_classes();)
1823
1824 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1825 ClassLoaderDataGraph::clean_module_and_package_info();
1826 constraints()->purge_loader_constraints();
1827 resolution_errors()->purge_resolution_errors();
1828 }
1829 }
1830
1831 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1832
1833 if (unloading_occurred) {
1834 SymbolTable::trigger_cleanup();
1835
1836 // Oops referenced by the protection domain cache table may get unreachable independently
1837 // of the class loader (eg. cached protection domain oops). So we need to
1838 // explicitly unlink them here.
1839 // All protection domain oops are linked to the caller class, so if nothing
1840 // unloads, this is not needed.
1841 _pd_cache_table->trigger_cleanup();
1842 }
1843
1844 return unloading_occurred;
1845 }
1846
1847 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1848 f->do_oop(&_java_system_loader);
1849 f->do_oop(&_java_platform_loader);
1850 f->do_oop(&_system_loader_lock_obj);
1851 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1852
1853 // Visit extra methods
1854 invoke_method_table()->oops_do(f);
1855
1856 if (include_handles) {
1857 OopStorageSet::vm_global()->oops_do(f);
1858 }
1859 }
1860
1861 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1862 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1863 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1864 it->push(well_known_klass_addr((WKID)id));
1865 }
1866 }
1867
1868 void SystemDictionary::methods_do(void f(Method*)) {
1869 // Walk methods in loaded classes
1870 MutexLocker ml(ClassLoaderDataGraph_lock);
1871 ClassLoaderDataGraph::methods_do(f);
1872 // Walk method handle intrinsics
1873 invoke_method_table()->methods_do(f);
1874 }
1875
1876 // ----------------------------------------------------------------------------
1877 // Initialization
1878
1879 void SystemDictionary::initialize(TRAPS) {
1880 // Allocate arrays
1881 _placeholders = new PlaceholderTable(_placeholder_table_size);
1882 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1883 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1884 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1885 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1886
1887 // Allocate private object used as system class loader lock
1888 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1889 // Initialize basic classes
1890 resolve_well_known_classes(CHECK);
1891 }
1892
1893 // Compact table of directions on the initialization of klasses:
1894 static const short wk_init_info[] = {
1895 #define WK_KLASS_INIT_INFO(name, symbol) \
1896 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1897
1898 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1899 #undef WK_KLASS_INIT_INFO
1900 0
1901 };
1902
1903 #ifdef ASSERT
1904 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1905 int sid;
1906 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1907 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1908 if (class_name == symbol) {
1909 return true;
1910 }
1911 }
1912 return false;
1913 }
1914 #endif
1915
1916 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1917 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1918 int sid = wk_init_info[id - FIRST_WKID];
1919 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1920 InstanceKlass** klassp = &_well_known_klasses[id];
1921
1922 if ((*klassp) == NULL) {
1923 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1924 (*klassp) = InstanceKlass::cast(k);
1925 }
1926 return ((*klassp) != NULL);
1927 }
1928
1929 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1930 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1931 for (int id = (int)start_id; id < (int)limit_id; id++) {
1932 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1933 resolve_wk_klass((WKID)id, CHECK);
1934 }
1935
1936 // move the starting value forward to the limit:
1937 start_id = limit_id;
1938 }
1939
1940 bool SystemDictionary::register_native(Klass* k, Symbol* name, Symbol* signature, address entry, TRAPS) {
1941 Method* method = k->lookup_method(name, signature);
1942 if (method == NULL) {
1943 ResourceMark rm;
1944 stringStream st;
1945 st.print("Method '");
1946 Method::print_external_name(&st, k, name, signature);
1947 st.print("' name or signature does not match");
1948 THROW_MSG_(vmSymbols::java_lang_NoSuchMethodError(), st.as_string(), false);
1949 }
1950 if (!method->is_native()) {
1951 // trying to register to a non-native method, see if a JVM TI agent has added prefix(es)
1952 method = find_prefixed_native(k, name, signature, THREAD);
1953 if (method == NULL) {
1954 ResourceMark rm;
1955 stringStream st;
1956 st.print("Method '");
1957 Method::print_external_name(&st, k, name, signature);
1958 st.print("' is not declared as native");
1959 THROW_MSG_(vmSymbols::java_lang_NoSuchMethodError(), st.as_string(), false);
1960 }
1961 }
1962
1963 if (entry != NULL) {
1964 method->set_native_function(entry,
1965 Method::native_bind_event_is_interesting);
1966 } else {
1967 method->clear_native_function();
1968 }
1969 if (PrintJNIResolving) {
1970 ResourceMark rm(THREAD);
1971 tty->print_cr("[Registering JNI native method %s.%s]",
1972 method->method_holder()->external_name(),
1973 method->name()->as_C_string());
1974 }
1975 return true;
1976 }
1977
1978 // The RegisterNatives call being attempted tried to register with a method that
1979 // is not native. Ask JVM TI what prefixes have been specified. Then check
1980 // to see if the native method is now wrapped with the prefixes. See the
1981 // SetNativeMethodPrefix(es) functions in the JVM TI Spec for details.
1982 Method* SystemDictionary::find_prefixed_native(Klass* k, Symbol* name, Symbol* signature, TRAPS) {
1983 #if INCLUDE_JVMTI
1984 ResourceMark rm(THREAD);
1985 Method* method;
1986 int name_len = name->utf8_length();
1987 char* name_str = name->as_utf8();
1988 int prefix_count;
1989 char** prefixes = JvmtiExport::get_all_native_method_prefixes(&prefix_count);
1990 for (int i = 0; i < prefix_count; i++) {
1991 char* prefix = prefixes[i];
1992 int prefix_len = (int)strlen(prefix);
1993
1994 // try adding this prefix to the method name and see if it matches another method name
1995 int trial_len = name_len + prefix_len;
1996 char* trial_name_str = NEW_RESOURCE_ARRAY(char, trial_len + 1);
1997 strcpy(trial_name_str, prefix);
1998 strcat(trial_name_str, name_str);
1999 TempNewSymbol trial_name = SymbolTable::probe(trial_name_str, trial_len);
2000 if (trial_name == NULL) {
2001 continue; // no such symbol, so this prefix wasn't used, try the next prefix
2002 }
2003 method = k->lookup_method(trial_name, signature);
2004 if (method == NULL) {
2005 continue; // signature doesn't match, try the next prefix
2006 }
2007 if (method->is_native()) {
2008 method->set_is_prefixed_native();
2009 return method; // wahoo, we found a prefixed version of the method, return it
2010 }
2011 // found as non-native, so prefix is good, add it, probably just need more prefixes
2012 name_len = trial_len;
2013 name_str = trial_name_str;
2014 }
2015 #endif // INCLUDE_JVMTI
2016 return NULL; // not found
2017 }
2018
2019 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2020 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
2021
2022 // Create the ModuleEntry for java.base. This call needs to be done here,
2023 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2024 ClassLoader::classLoader_init2(CHECK);
2025
2026 // Preload commonly used klasses
2027 WKID scan = FIRST_WKID;
2028 // first do Object, then String, Class
2029 #if INCLUDE_CDS
2030 if (UseSharedSpaces) {
2031 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2032
2033 // It's unsafe to access the archived heap regions before they
2034 // are fixed up, so we must do the fixup as early as possible
2035 // before the archived java objects are accessed by functions
2036 // such as java_lang_Class::restore_archived_mirror and
2037 // ConstantPool::restore_unshareable_info (restores the archived
2038 // resolved_references array object).
2039 //
2040 // HeapShared::fixup_mapped_heap_regions() fills the empty
2041 // spaces in the archived heap regions and may use
2042 // SystemDictionary::Object_klass(), so we can do this only after
2043 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2044 // call. No mirror objects are accessed/restored in the above call.
2045 // Mirrors are restored after java.lang.Class is loaded.
2046 HeapShared::fixup_mapped_heap_regions();
2047
2048 // Initialize the constant pool for the Object_class
2049 assert(Object_klass()->is_shared(), "must be");
2050 Object_klass()->constants()->restore_unshareable_info(CHECK);
2051 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2052 } else
2053 #endif
2054 {
2055 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2056 }
2057
2058 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2059
2060 // Register native methods of Object
2061 register_native(Object_klass(), vmSymbols::hashCode_name(), vmSymbols::void_int_signature(), (address)&JVM_IHashCode, THREAD);
2062 register_native(Object_klass(), vmSymbols::wait_name(), vmSymbols::long_void_signature(), (address)&JVM_MonitorWait, THREAD);
2063 register_native(Object_klass(), vmSymbols::notify_name(), vmSymbols::void_method_signature(), (address)&JVM_MonitorNotify, THREAD);
2064 register_native(Object_klass(), vmSymbols::notifyAll_name(), vmSymbols::void_method_signature(), (address)&JVM_MonitorNotifyAll, THREAD);
2065 register_native(Object_klass(), vmSymbols::clone_name(), vmSymbols::void_object_signature(), (address)&JVM_Clone, THREAD);
2066
2067 // Calculate offsets for String and Class classes since they are loaded and
2068 // can be used after this point.
2069 java_lang_String::compute_offsets();
2070 java_lang_Class::compute_offsets();
2071
2072 // Fixup mirrors for classes loaded before java.lang.Class.
2073 // These calls iterate over the objects currently in the perm gen
2074 // so calling them at this point is matters (not before when there
2075 // are fewer objects and not later after there are more objects
2076 // in the perm gen.
2077 Universe::initialize_basic_type_mirrors(CHECK);
2078 Universe::fixup_mirrors(CHECK);
2079
2080 // do a bunch more:
2081 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2082
2083 // Preload ref klasses and set reference types
2084 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2085 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2086
2087 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2088 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2089 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2090 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2091 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2092
2093 // JSR 292 classes
2094 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2095 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2096 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2097 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2098 WKID last = WKID_LIMIT;
2099 resolve_wk_klasses_until(last, scan, CHECK);
2100
2101 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2102 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2103 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2104 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2105 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2106 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2107 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2108 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2109 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2110 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2111
2112 { // Compute whether we should use checkPackageAccess or NOT
2113 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2114 _has_checkPackageAccess = (method != NULL);
2115 }
2116
2117 #ifdef ASSERT
2118 if (UseSharedSpaces) {
2119 assert(JvmtiExport::is_early_phase(),
2120 "All well known classes must be resolved in JVMTI early phase");
2121 for (int i = FIRST_WKID; i < last; i++) {
2122 InstanceKlass* k = _well_known_klasses[i];
2123 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2124 }
2125 }
2126 #endif
2127 }
2128
2129 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2130 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2131 BasicType SystemDictionary::box_klass_type(Klass* k) {
2132 assert(k != NULL, "");
2133 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2134 if (_box_klasses[i] == k)
2135 return (BasicType)i;
2136 }
2137 return T_OBJECT;
2138 }
2139
2140 // Constraints on class loaders. The details of the algorithm can be
2141 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2142 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2143 // that the dictionary needs to maintain a set of contraints that
2144 // must be satisfied by all classes in the dictionary.
2145 // if defining is true, then LinkageError if already in dictionary
2146 // if initiating loader, then ok if InstanceKlass matches existing entry
2147
2148 void SystemDictionary::check_constraints(unsigned int d_hash,
2149 InstanceKlass* k,
2150 Handle class_loader,
2151 bool defining,
2152 TRAPS) {
2153 ResourceMark rm(THREAD);
2154 stringStream ss;
2155 bool throwException = false;
2156
2157 {
2158 Symbol *name = k->name();
2159 ClassLoaderData *loader_data = class_loader_data(class_loader);
2160
2161 MutexLocker mu(SystemDictionary_lock, THREAD);
2162
2163 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2164 if (check != NULL) {
2165 // If different InstanceKlass - duplicate class definition,
2166 // else - ok, class loaded by a different thread in parallel.
2167 // We should only have found it if it was done loading and ok to use.
2168 // The dictionary only holds instance classes, placeholders
2169 // also hold array classes.
2170
2171 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2172 if ((defining == true) || (k != check)) {
2173 throwException = true;
2174 ss.print("loader %s", loader_data->loader_name_and_id());
2175 ss.print(" attempted duplicate %s definition for %s. (%s)",
2176 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2177 } else {
2178 return;
2179 }
2180 }
2181
2182 #ifdef ASSERT
2183 Symbol* ph_check = find_placeholder(name, loader_data);
2184 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2185 #endif
2186
2187 if (throwException == false) {
2188 if (constraints()->check_or_update(k, class_loader, name) == false) {
2189 throwException = true;
2190 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2191 ss.print(" wants to load %s %s.",
2192 k->external_kind(), k->external_name());
2193 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2194 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2195 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2196 existing_klass->external_kind(),
2197 existing_klass->class_loader_data()->loader_name_and_id(),
2198 existing_klass->class_in_module_of_loader(false, true));
2199 } else {
2200 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2201 }
2202 }
2203 }
2204 }
2205
2206 // Throw error now if needed (cannot throw while holding
2207 // SystemDictionary_lock because of rank ordering)
2208 if (throwException == true) {
2209 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2210 }
2211 }
2212
2213 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2214 // have been called.
2215 void SystemDictionary::update_dictionary(unsigned int d_hash,
2216 int p_index, unsigned int p_hash,
2217 InstanceKlass* k,
2218 Handle class_loader,
2219 TRAPS) {
2220 // Compile_lock prevents systemDictionary updates during compilations
2221 assert_locked_or_safepoint(Compile_lock);
2222 Symbol* name = k->name();
2223 ClassLoaderData *loader_data = class_loader_data(class_loader);
2224
2225 {
2226 MutexLocker mu1(SystemDictionary_lock, THREAD);
2227
2228 // See whether biased locking is enabled and if so set it for this
2229 // klass.
2230 // Note that this must be done past the last potential blocking
2231 // point / safepoint. We might enable biased locking lazily using a
2232 // VM_Operation to iterate the SystemDictionary and installing the
2233 // biasable mark word into each InstanceKlass's prototype header.
2234 // To avoid race conditions where we accidentally miss enabling the
2235 // optimization for one class in the process of being added to the
2236 // dictionary, we must not safepoint after the test of
2237 // BiasedLocking::enabled().
2238 if (UseBiasedLocking && BiasedLocking::enabled()) {
2239 // Set biased locking bit for all loaded classes; it will be
2240 // cleared if revocation occurs too often for this type
2241 // NOTE that we must only do this when the class is initally
2242 // defined, not each time it is referenced from a new class loader
2243 if (k->class_loader() == class_loader()) {
2244 k->set_prototype_header(markWord::biased_locking_prototype());
2245 }
2246 }
2247
2248 // Make a new dictionary entry.
2249 Dictionary* dictionary = loader_data->dictionary();
2250 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2251 if (sd_check == NULL) {
2252 dictionary->add_klass(d_hash, name, k);
2253 }
2254 #ifdef ASSERT
2255 sd_check = find_class(d_hash, name, dictionary);
2256 assert (sd_check != NULL, "should have entry in dictionary");
2257 // Note: there may be a placeholder entry: for circularity testing
2258 // or for parallel defines
2259 #endif
2260 SystemDictionary_lock->notify_all();
2261 }
2262 }
2263
2264
2265 // Try to find a class name using the loader constraints. The
2266 // loader constraints might know about a class that isn't fully loaded
2267 // yet and these will be ignored.
2268 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2269 Symbol* class_name, Handle class_loader, TRAPS) {
2270
2271 // First see if it has been loaded directly.
2272 // Force the protection domain to be null. (This removes protection checks.)
2273 Handle no_protection_domain;
2274 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2275 no_protection_domain, CHECK_NULL);
2276 if (klass != NULL)
2277 return klass;
2278
2279 // Now look to see if it has been loaded elsewhere, and is subject to
2280 // a loader constraint that would require this loader to return the
2281 // klass that is already loaded.
2282 if (FieldType::is_array(class_name)) {
2283 // For array classes, their Klass*s are not kept in the
2284 // constraint table. The element Klass*s are.
2285 FieldArrayInfo fd;
2286 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2287 if (t != T_OBJECT) {
2288 klass = Universe::typeArrayKlassObj(t);
2289 } else {
2290 MutexLocker mu(SystemDictionary_lock, THREAD);
2291 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2292 }
2293 // If element class already loaded, allocate array klass
2294 if (klass != NULL) {
2295 klass = klass->array_klass_or_null(fd.dimension());
2296 }
2297 } else {
2298 MutexLocker mu(SystemDictionary_lock, THREAD);
2299 // Non-array classes are easy: simply check the constraint table.
2300 klass = constraints()->find_constrained_klass(class_name, class_loader);
2301 }
2302
2303 return klass;
2304 }
2305
2306
2307 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2308 Handle class_loader1,
2309 Handle class_loader2,
2310 Thread* THREAD) {
2311 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2312 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2313
2314 Symbol* constraint_name = NULL;
2315 // Needs to be in same scope as constraint_name in case a Symbol is created and
2316 // assigned to constraint_name.
2317 FieldArrayInfo fd;
2318 if (!FieldType::is_array(class_name)) {
2319 constraint_name = class_name;
2320 } else {
2321 // For array classes, their Klass*s are not kept in the
2322 // constraint table. The element classes are.
2323 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2324 // primitive types always pass
2325 if (t != T_OBJECT) {
2326 return true;
2327 } else {
2328 constraint_name = fd.object_key();
2329 }
2330 }
2331
2332 Dictionary* dictionary1 = loader_data1->dictionary();
2333 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2334
2335 Dictionary* dictionary2 = loader_data2->dictionary();
2336 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2337
2338 {
2339 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2340 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2341 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2342 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2343 klass2, class_loader2);
2344 }
2345 }
2346
2347 // Add entry to resolution error table to record the error when the first
2348 // attempt to resolve a reference to a class has failed.
2349 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2350 Symbol* error, Symbol* message) {
2351 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2352 int index = resolution_errors()->hash_to_index(hash);
2353 {
2354 MutexLocker ml(SystemDictionary_lock, Thread::current());
2355 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2356 }
2357 }
2358
2359 // Delete a resolution error for RedefineClasses for a constant pool is going away
2360 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2361 resolution_errors()->delete_entry(pool);
2362 }
2363
2364 // Lookup resolution error table. Returns error if found, otherwise NULL.
2365 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2366 Symbol** message) {
2367 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2368 int index = resolution_errors()->hash_to_index(hash);
2369 {
2370 MutexLocker ml(SystemDictionary_lock, Thread::current());
2371 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2372 if (entry != NULL) {
2373 *message = entry->message();
2374 return entry->error();
2375 } else {
2376 return NULL;
2377 }
2378 }
2379 }
2380
2381
2382 // Signature constraints ensure that callers and callees agree about
2383 // the meaning of type names in their signatures. This routine is the
2384 // intake for constraints. It collects them from several places:
2385 //
2386 // * LinkResolver::resolve_method (if check_access is true) requires
2387 // that the resolving class (the caller) and the defining class of
2388 // the resolved method (the callee) agree on each type in the
2389 // method's signature.
2390 //
2391 // * LinkResolver::resolve_interface_method performs exactly the same
2392 // checks.
2393 //
2394 // * LinkResolver::resolve_field requires that the constant pool
2395 // attempting to link to a field agree with the field's defining
2396 // class about the type of the field signature.
2397 //
2398 // * klassVtable::initialize_vtable requires that, when a class
2399 // overrides a vtable entry allocated by a superclass, that the
2400 // overriding method (i.e., the callee) agree with the superclass
2401 // on each type in the method's signature.
2402 //
2403 // * klassItable::initialize_itable requires that, when a class fills
2404 // in its itables, for each non-abstract method installed in an
2405 // itable, the method (i.e., the callee) agree with the interface
2406 // on each type in the method's signature.
2407 //
2408 // All those methods have a boolean (check_access, checkconstraints)
2409 // which turns off the checks. This is used from specialized contexts
2410 // such as bootstrapping, dumping, and debugging.
2411 //
2412 // No direct constraint is placed between the class and its
2413 // supertypes. Constraints are only placed along linked relations
2414 // between callers and callees. When a method overrides or implements
2415 // an abstract method in a supertype (superclass or interface), the
2416 // constraints are placed as if the supertype were the caller to the
2417 // overriding method. (This works well, since callers to the
2418 // supertype have already established agreement between themselves and
2419 // the supertype.) As a result of all this, a class can disagree with
2420 // its supertype about the meaning of a type name, as long as that
2421 // class neither calls a relevant method of the supertype, nor is
2422 // called (perhaps via an override) from the supertype.
2423 //
2424 //
2425 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2426 //
2427 // Make sure all class components (including arrays) in the given
2428 // signature will be resolved to the same class in both loaders.
2429 // Returns the name of the type that failed a loader constraint check, or
2430 // NULL if no constraint failed. No exception except OOME is thrown.
2431 // Arrays are not added to the loader constraint table, their elements are.
2432 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2433 Handle loader1, Handle loader2,
2434 bool is_method, TRAPS) {
2435 // Nothing to do if loaders are the same.
2436 if (loader1() == loader2()) {
2437 return NULL;
2438 }
2439
2440 SignatureStream sig_strm(signature, is_method);
2441 while (!sig_strm.is_done()) {
2442 if (sig_strm.is_object()) {
2443 Symbol* sig = sig_strm.as_symbol();
2444 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2445 return sig;
2446 }
2447 }
2448 sig_strm.next();
2449 }
2450 return NULL;
2451 }
2452
2453
2454 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2455 Symbol* signature,
2456 TRAPS) {
2457 methodHandle empty;
2458 assert(MethodHandles::is_signature_polymorphic(iid) &&
2459 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2460 iid != vmIntrinsics::_invokeGeneric,
2461 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2462
2463 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2464 int index = invoke_method_table()->hash_to_index(hash);
2465 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2466 methodHandle m;
2467 if (spe == NULL || spe->method() == NULL) {
2468 spe = NULL;
2469 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2470 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2471 if (!Arguments::is_interpreter_only()) {
2472 // Generate a compiled form of the MH intrinsic.
2473 AdapterHandlerLibrary::create_native_wrapper(m);
2474 // Check if have the compiled code.
2475 if (!m->has_compiled_code()) {
2476 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2477 "Out of space in CodeCache for method handle intrinsic", empty);
2478 }
2479 }
2480 // Now grab the lock. We might have to throw away the new method,
2481 // if a racing thread has managed to install one at the same time.
2482 {
2483 MutexLocker ml(SystemDictionary_lock, THREAD);
2484 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2485 if (spe == NULL)
2486 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2487 if (spe->method() == NULL)
2488 spe->set_method(m());
2489 }
2490 }
2491
2492 assert(spe != NULL && spe->method() != NULL, "");
2493 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2494 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2495 "MH intrinsic invariant");
2496 return spe->method();
2497 }
2498
2499 // Helper for unpacking the return value from linkMethod and linkCallSite.
2500 static methodHandle unpack_method_and_appendix(Handle mname,
2501 Klass* accessing_klass,
2502 objArrayHandle appendix_box,
2503 Handle* appendix_result,
2504 TRAPS) {
2505 methodHandle empty;
2506 if (mname.not_null()) {
2507 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2508 if (m != NULL) {
2509 oop appendix = appendix_box->obj_at(0);
2510 if (TraceMethodHandles) {
2511 #ifndef PRODUCT
2512 ttyLocker ttyl;
2513 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2514 m->print();
2515 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2516 tty->cr();
2517 #endif //PRODUCT
2518 }
2519 (*appendix_result) = Handle(THREAD, appendix);
2520 // the target is stored in the cpCache and if a reference to this
2521 // MemberName is dropped we need a way to make sure the
2522 // class_loader containing this method is kept alive.
2523 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2524 this_key->record_dependency(m->method_holder());
2525 return methodHandle(THREAD, m);
2526 }
2527 }
2528 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2529 return empty;
2530 }
2531
2532 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2533 Symbol* name,
2534 Symbol* signature,
2535 Klass* accessing_klass,
2536 Handle *appendix_result,
2537 TRAPS) {
2538 methodHandle empty;
2539 assert(THREAD->can_call_java() ,"");
2540 Handle method_type =
2541 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2542
2543 int ref_kind = JVM_REF_invokeVirtual;
2544 oop name_oop = StringTable::intern(name, CHECK_(empty));
2545 Handle name_str (THREAD, name_oop);
2546 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2547 assert(appendix_box->obj_at(0) == NULL, "");
2548
2549 // This should not happen. JDK code should take care of that.
2550 if (accessing_klass == NULL || method_type.is_null()) {
2551 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2552 }
2553
2554 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2555 JavaCallArguments args;
2556 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2557 args.push_int(ref_kind);
2558 args.push_oop(Handle(THREAD, klass->java_mirror()));
2559 args.push_oop(name_str);
2560 args.push_oop(method_type);
2561 args.push_oop(appendix_box);
2562 JavaValue result(T_OBJECT);
2563 JavaCalls::call_static(&result,
2564 SystemDictionary::MethodHandleNatives_klass(),
2565 vmSymbols::linkMethod_name(),
2566 vmSymbols::linkMethod_signature(),
2567 &args, CHECK_(empty));
2568 Handle mname(THREAD, (oop) result.get_jobject());
2569 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2570 }
2571
2572 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2573 // We must ensure that all class loaders everywhere will reach this class, for any client.
2574 // This is a safe bet for public classes in java.lang, such as Object and String.
2575 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2576 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2577 static bool is_always_visible_class(oop mirror) {
2578 Klass* klass = java_lang_Class::as_Klass(mirror);
2579 if (klass->is_objArray_klass()) {
2580 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2581 }
2582 if (klass->is_typeArray_klass()) {
2583 return true; // primitive array
2584 }
2585 assert(klass->is_instance_klass(), "%s", klass->external_name());
2586 return klass->is_public() &&
2587 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2588 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2589 }
2590
2591
2592 // Return the Java mirror (java.lang.Class instance) for a single-character
2593 // descriptor. This result, when available, is the same as produced by the
2594 // heavier API point of the same name that takes a Symbol.
2595 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2596 return java_lang_Class::primitive_mirror(char2type(signature_char));
2597 }
2598
2599 // Find or construct the Java mirror (java.lang.Class instance) for a
2600 // for the given field type signature, as interpreted relative to the
2601 // given class loader. Handles primitives, void, references, arrays,
2602 // and all other reflectable types, except method types.
2603 // N.B. Code in reflection should use this entry point.
2604 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2605 Klass* accessing_klass,
2606 Handle class_loader,
2607 Handle protection_domain,
2608 SignatureStream::FailureMode failure_mode,
2609 TRAPS) {
2610 Handle empty;
2611
2612 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2613 "one or the other, or perhaps neither");
2614
2615 Symbol* type = signature;
2616
2617 // What we have here must be a valid field descriptor,
2618 // and all valid field descriptors are supported.
2619 // Produce the same java.lang.Class that reflection reports.
2620 if (type->utf8_length() == 1) {
2621
2622 // It's a primitive. (Void has a primitive mirror too.)
2623 char ch = type->char_at(0);
2624 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2625 return Handle(THREAD, find_java_mirror_for_type(ch));
2626
2627 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2628
2629 // It's a reference type.
2630 if (accessing_klass != NULL) {
2631 class_loader = Handle(THREAD, accessing_klass->class_loader());
2632 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2633 }
2634 Klass* constant_type_klass;
2635 if (failure_mode == SignatureStream::ReturnNull) {
2636 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2637 CHECK_(empty));
2638 } else {
2639 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2640 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2641 throw_error, CHECK_(empty));
2642 }
2643 if (constant_type_klass == NULL) {
2644 return Handle(); // report failure this way
2645 }
2646 Handle mirror(THREAD, constant_type_klass->java_mirror());
2647
2648 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2649 if (accessing_klass != NULL) {
2650 Klass* sel_klass = constant_type_klass;
2651 bool fold_type_to_class = true;
2652 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2653 fold_type_to_class, CHECK_(empty));
2654 }
2655
2656 return mirror;
2657
2658 }
2659
2660 // Fall through to an error.
2661 assert(false, "unsupported mirror syntax");
2662 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2663 }
2664
2665
2666 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2667 // signature, as interpreted relative to the given class loader.
2668 // Because of class loader constraints, all method handle usage must be
2669 // consistent with this loader.
2670 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2671 Klass* accessing_klass,
2672 TRAPS) {
2673 Handle empty;
2674 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2675 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2676 int index = invoke_method_table()->hash_to_index(hash);
2677 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2678 if (spe != NULL && spe->method_type() != NULL) {
2679 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2680 return Handle(THREAD, spe->method_type());
2681 } else if (!THREAD->can_call_java()) {
2682 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2683 return Handle(); // do not attempt from within compiler, unless it was cached
2684 }
2685
2686 Handle class_loader, protection_domain;
2687 if (accessing_klass != NULL) {
2688 class_loader = Handle(THREAD, accessing_klass->class_loader());
2689 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2690 }
2691 bool can_be_cached = true;
2692 int npts = ArgumentCount(signature).size();
2693 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2694 int arg = 0;
2695 Handle rt; // the return type from the signature
2696 ResourceMark rm(THREAD);
2697 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2698 oop mirror = NULL;
2699 if (can_be_cached) {
2700 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2701 mirror = ss.as_java_mirror(Handle(), Handle(),
2702 SignatureStream::ReturnNull, CHECK_(empty));
2703 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2704 // Fall back to accessing_klass context.
2705 can_be_cached = false;
2706 }
2707 }
2708 if (!can_be_cached) {
2709 // Resolve, throwing a real error if it doesn't work.
2710 mirror = ss.as_java_mirror(class_loader, protection_domain,
2711 SignatureStream::NCDFError, CHECK_(empty));
2712 }
2713 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2714 if (ss.at_return_type())
2715 rt = Handle(THREAD, mirror);
2716 else
2717 pts->obj_at_put(arg++, mirror);
2718
2719 // Check accessibility.
2720 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2721 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2722 mirror = NULL; // safety
2723 // Emulate ConstantPool::verify_constant_pool_resolve.
2724 bool fold_type_to_class = true;
2725 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2726 fold_type_to_class, CHECK_(empty));
2727 }
2728 }
2729 assert(arg == npts, "");
2730
2731 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2732 JavaCallArguments args(Handle(THREAD, rt()));
2733 args.push_oop(pts);
2734 JavaValue result(T_OBJECT);
2735 JavaCalls::call_static(&result,
2736 SystemDictionary::MethodHandleNatives_klass(),
2737 vmSymbols::findMethodHandleType_name(),
2738 vmSymbols::findMethodHandleType_signature(),
2739 &args, CHECK_(empty));
2740 Handle method_type(THREAD, (oop) result.get_jobject());
2741
2742 if (can_be_cached) {
2743 // We can cache this MethodType inside the JVM.
2744 MutexLocker ml(SystemDictionary_lock, THREAD);
2745 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2746 if (spe == NULL)
2747 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2748 if (spe->method_type() == NULL) {
2749 spe->set_method_type(method_type());
2750 }
2751 }
2752
2753 // report back to the caller with the MethodType
2754 return method_type;
2755 }
2756
2757 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2758 Klass* accessing_klass,
2759 TRAPS) {
2760 Handle empty;
2761 ResourceMark rm(THREAD);
2762 SignatureStream ss(signature, /*is_method=*/ false);
2763 if (!ss.is_done()) {
2764 Handle class_loader, protection_domain;
2765 if (accessing_klass != NULL) {
2766 class_loader = Handle(THREAD, accessing_klass->class_loader());
2767 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2768 }
2769 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2770 ss.next();
2771 if (ss.is_done()) {
2772 return Handle(THREAD, mirror);
2773 }
2774 }
2775 return empty;
2776 }
2777
2778 // Ask Java code to find or construct a method handle constant.
2779 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2780 int ref_kind, //e.g., JVM_REF_invokeVirtual
2781 Klass* callee,
2782 Symbol* name,
2783 Symbol* signature,
2784 TRAPS) {
2785 Handle empty;
2786 if (caller == NULL) {
2787 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2788 }
2789 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2790 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2791
2792 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2793 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2794 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2795 java_lang_invoke_MemberName::set_name (mname(), name_str());
2796 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2797 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2798
2799 if (ref_kind == JVM_REF_invokeVirtual &&
2800 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2801 // Skip resolution for public signature polymorphic methods such as
2802 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2803 // They require appendix argument which MemberName resolution doesn't handle.
2804 // There's special logic on JDK side to handle them
2805 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2806 } else {
2807 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2808 }
2809
2810 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2811 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2812
2813 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2814 JavaCallArguments args;
2815 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2816 args.push_int(ref_kind);
2817 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2818 args.push_oop(name_str);
2819 args.push_oop(type);
2820 JavaValue result(T_OBJECT);
2821 JavaCalls::call_static(&result,
2822 SystemDictionary::MethodHandleNatives_klass(),
2823 vmSymbols::linkMethodHandleConstant_name(),
2824 vmSymbols::linkMethodHandleConstant_signature(),
2825 &args, CHECK_(empty));
2826 return Handle(THREAD, (oop) result.get_jobject());
2827 }
2828
2829 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2830 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2831 // with linkage results being stored back into the bootstrap specifier.
2832 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2833 // Resolve the bootstrap specifier, its name, type, and static arguments
2834 bootstrap_specifier.resolve_bsm(CHECK);
2835
2836 // This should not happen. JDK code should take care of that.
2837 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2838 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2839 }
2840
2841 bool is_indy = bootstrap_specifier.is_method_call();
2842 objArrayHandle appendix_box;
2843 if (is_indy) {
2844 // Some method calls may require an appendix argument. Arrange to receive it.
2845 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2846 assert(appendix_box->obj_at(0) == NULL, "");
2847 }
2848
2849 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2850 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2851 JavaCallArguments args;
2852 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2853 args.push_int(bootstrap_specifier.bss_index());
2854 args.push_oop(bootstrap_specifier.bsm());
2855 args.push_oop(bootstrap_specifier.name_arg());
2856 args.push_oop(bootstrap_specifier.type_arg());
2857 args.push_oop(bootstrap_specifier.arg_values());
2858 if (is_indy) {
2859 args.push_oop(appendix_box);
2860 }
2861 JavaValue result(T_OBJECT);
2862 JavaCalls::call_static(&result,
2863 SystemDictionary::MethodHandleNatives_klass(),
2864 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2865 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2866 &args, CHECK);
2867
2868 Handle value(THREAD, (oop) result.get_jobject());
2869 if (is_indy) {
2870 Handle appendix;
2871 methodHandle method = unpack_method_and_appendix(value,
2872 bootstrap_specifier.caller(),
2873 appendix_box,
2874 &appendix, CHECK);
2875 bootstrap_specifier.set_resolved_method(method, appendix);
2876 } else {
2877 bootstrap_specifier.set_resolved_value(value);
2878 }
2879
2880 // sanity check
2881 assert(bootstrap_specifier.is_resolved() ||
2882 (bootstrap_specifier.is_method_call() &&
2883 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2884 }
2885
2886 // Protection domain cache table handling
2887
2888 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2889 return _pd_cache_table->get(protection_domain);
2890 }
2891
2892 // ----------------------------------------------------------------------------
2893
2894 void SystemDictionary::print_on(outputStream *st) {
2895 CDS_ONLY(SystemDictionaryShared::print_on(st));
2896 GCMutexLocker mu(SystemDictionary_lock);
2897
2898 ClassLoaderDataGraph::print_dictionary(st);
2899
2900 // Placeholders
2901 placeholders()->print_on(st);
2902 st->cr();
2903
2904 // loader constraints - print under SD_lock
2905 constraints()->print_on(st);
2906 st->cr();
2907
2908 _pd_cache_table->print_on(st);
2909 st->cr();
2910 }
2911
2912 void SystemDictionary::print() { print_on(tty); }
2913
2914 void SystemDictionary::verify() {
2915 guarantee(constraints() != NULL,
2916 "Verify of loader constraints failed");
2917 guarantee(placeholders()->number_of_entries() >= 0,
2918 "Verify of placeholders failed");
2919
2920 GCMutexLocker mu(SystemDictionary_lock);
2921
2922 // Verify dictionary
2923 ClassLoaderDataGraph::verify_dictionary();
2924
2925 placeholders()->verify();
2926
2927 // Verify constraint table
2928 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2929 constraints()->verify(placeholders());
2930
2931 _pd_cache_table->verify();
2932 }
2933
2934 void SystemDictionary::dump(outputStream *st, bool verbose) {
2935 assert_locked_or_safepoint(SystemDictionary_lock);
2936 if (verbose) {
2937 print_on(st);
2938 } else {
2939 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2940 ClassLoaderDataGraph::print_table_statistics(st);
2941 placeholders()->print_table_statistics(st, "Placeholder Table");
2942 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2943 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2944 }
2945 }
2946
2947 TableStatistics SystemDictionary::placeholders_statistics() {
2948 MutexLocker ml(SystemDictionary_lock);
2949 return placeholders()->statistics_calculate();
2950 }
2951
2952 TableStatistics SystemDictionary::loader_constraints_statistics() {
2953 MutexLocker ml(SystemDictionary_lock);
2954 return constraints()->statistics_calculate();
2955 }
2956
2957 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2958 MutexLocker ml(SystemDictionary_lock);
2959 return pd_cache_table()->statistics_calculate();
2960 }
2961
2962 // Utility for dumping dictionaries.
2963 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2964 DCmdWithParser(output, heap),
2965 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2966 "BOOLEAN", false, "false") {
2967 _dcmdparser.add_dcmd_option(&_verbose);
2968 }
2969
2970 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2971 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2972 _verbose.value());
2973 VMThread::execute(&dumper);
2974 }
2975
2976 int SystemDictionaryDCmd::num_arguments() {
2977 ResourceMark rm;
2978 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2979 if (dcmd != NULL) {
2980 DCmdMark mark(dcmd);
2981 return dcmd->_dcmdparser.num_arguments();
2982 } else {
2983 return 0;
2984 }
2985 }