1 /*
2 * Copyright (c) 1997, 2017, 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 "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/protectionDomainCache.hpp"
39 #include "classfile/resolutionErrors.hpp"
40 #include "classfile/stringTable.hpp"
41 #include "classfile/systemDictionary.hpp"
42 #include "classfile/vmSymbols.hpp"
43 #include "code/codeCache.hpp"
44 #include "compiler/compileBroker.hpp"
45 #include "gc/shared/gcLocker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "interpreter/bytecodeStream.hpp"
48 #include "interpreter/interpreter.hpp"
49 #include "logging/log.hpp"
50 #include "memory/filemap.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "oops/instanceKlass.hpp"
54 #include "oops/instanceRefKlass.hpp"
55 #include "oops/klass.inline.hpp"
56 #include "oops/methodData.hpp"
57 #include "oops/objArrayKlass.hpp"
58 #include "oops/objArrayOop.inline.hpp"
59 #include "oops/oop.inline.hpp"
60 #include "oops/symbol.hpp"
61 #include "oops/typeArrayKlass.hpp"
62 #include "prims/jvm.h"
63 #include "prims/jvmtiEnvBase.hpp"
64 #include "prims/resolvedMethodTable.hpp"
65 #include "prims/methodHandles.hpp"
66 #include "runtime/arguments.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/fieldType.hpp"
69 #include "runtime/handles.inline.hpp"
70 #include "runtime/java.hpp"
71 #include "runtime/javaCalls.hpp"
72 #include "runtime/mutexLocker.hpp"
73 #include "runtime/orderAccess.inline.hpp"
74 #include "runtime/signature.hpp"
75 #include "services/classLoadingService.hpp"
76 #include "services/threadService.hpp"
77 #include "trace/traceMacros.hpp"
78 #include "utilities/macros.hpp"
79 #include "utilities/ticks.hpp"
80 #if INCLUDE_CDS
81 #include "classfile/sharedClassUtil.hpp"
82 #include "classfile/systemDictionaryShared.hpp"
83 #endif
84 #if INCLUDE_JVMCI
85 #include "jvmci/jvmciRuntime.hpp"
86 #endif
87 #if INCLUDE_TRACE
88 #include "trace/tracing.hpp"
89 #endif
90
91 PlaceholderTable* SystemDictionary::_placeholders = NULL;
92 Dictionary* SystemDictionary::_shared_dictionary = NULL;
93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
97
98 int SystemDictionary::_number_of_modifications = 0;
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107
108 bool SystemDictionary::_has_loadClassInternal = false;
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118
119 // ----------------------------------------------------------------------------
120 // Java-level SystemLoader
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader;
124 }
125
126 void SystemDictionary::compute_java_system_loader(TRAPS) {
127 Klass* system_klass = WK_KLASS(ClassLoader_klass);
128 JavaValue result(T_OBJECT);
129 JavaCalls::call_static(&result,
130 WK_KLASS(ClassLoader_klass),
131 vmSymbols::getSystemClassLoader_name(),
132 vmSymbols::void_classloader_signature(),
133 CHECK);
134
135 _java_system_loader = (oop)result.get_jobject();
136
137 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
138 }
139
140
141 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
142 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
143 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
144 }
145
146 // ----------------------------------------------------------------------------
147 // Parallel class loading check
148
149 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
150 if (UnsyncloadClass || class_loader.is_null()) return true;
151 if (AlwaysLockClassLoader) return false;
152 return java_lang_ClassLoader::parallelCapable(class_loader());
153 }
154 // ----------------------------------------------------------------------------
155 // ParallelDefineClass flag does not apply to bootclass loader
156 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
157 if (class_loader.is_null()) return false;
158 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
159 return true;
160 }
161 return false;
162 }
163
164 // Returns true if the passed class loader is the builtin application class loader
165 // or a custom system class loader. A customer system class loader can be
166 // specified via -Djava.system.class.loader.
167 bool SystemDictionary::is_system_class_loader(oop class_loader) {
168 if (class_loader == NULL) {
169 return false;
170 }
171 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
172 class_loader == _java_system_loader);
173 }
174
175 // Returns true if the passed class loader is the platform class loader.
176 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
177 if (class_loader == NULL) {
178 return false;
179 }
180 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
181 }
182
183 // ----------------------------------------------------------------------------
184 // Resolving of classes
185
186 // Forwards to resolve_or_null
187
188 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
189 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
190 if (HAS_PENDING_EXCEPTION || klass == NULL) {
191 // can return a null klass
192 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
193 }
194 return klass;
195 }
196
197 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
198 bool throw_error,
199 Klass* klass, TRAPS) {
200 if (HAS_PENDING_EXCEPTION) {
201 // If we have a pending exception we forward it to the caller, unless throw_error is true,
202 // in which case we have to check whether the pending exception is a ClassNotFoundException,
203 // and if so convert it to a NoClassDefFoundError
204 // And chain the original ClassNotFoundException
205 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
206 ResourceMark rm(THREAD);
207 assert(klass == NULL, "Should not have result with exception pending");
208 Handle e(THREAD, PENDING_EXCEPTION);
209 CLEAR_PENDING_EXCEPTION;
210 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
211 } else {
212 return NULL;
213 }
214 }
215 // Class not found, throw appropriate error or exception depending on value of throw_error
216 if (klass == NULL) {
217 ResourceMark rm(THREAD);
218 if (throw_error) {
219 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
220 } else {
221 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
222 }
223 }
224 return klass;
225 }
226
227
228 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
229 bool throw_error, TRAPS)
230 {
231 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
232 }
233
234
235 // Forwards to resolve_instance_class_or_null
236
237 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
238 assert(THREAD->can_call_java(),
239 "can not load classes with compiler thread: class=%s, classloader=%s",
240 class_name->as_C_string(),
241 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
242 if (FieldType::is_array(class_name)) {
243 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
244 } else if (FieldType::is_obj(class_name)) {
245 ResourceMark rm(THREAD);
246 // Ignore wrapping L and ;.
247 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
248 class_name->utf8_length() - 2, CHECK_NULL);
249 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
250 } else {
251 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
252 }
253 }
254
255 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
256 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
257 }
258
259 // Forwards to resolve_instance_class_or_null
260
261 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
262 Handle class_loader,
263 Handle protection_domain,
264 TRAPS) {
265 assert(FieldType::is_array(class_name), "must be array");
266 Klass* k = NULL;
267 FieldArrayInfo fd;
268 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
269 // of this call
270 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
271 if (t == T_OBJECT) {
272 // naked oop "k" is OK here -- we assign back into it
273 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
274 class_loader,
275 protection_domain,
276 CHECK_NULL);
277 if (k != NULL) {
278 k = k->array_klass(fd.dimension(), CHECK_NULL);
279 }
280 } else {
281 k = Universe::typeArrayKlassObj(t);
282 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
283 }
284 return k;
285 }
286
287
288 // Must be called for any super-class or super-interface resolution
289 // during class definition to allow class circularity checking
290 // super-interface callers:
291 // parse_interfaces - for defineClass & jvmtiRedefineClasses
292 // super-class callers:
293 // ClassFileParser - for defineClass & jvmtiRedefineClasses
294 // load_shared_class - while loading a class from shared archive
295 // resolve_instance_class_or_null:
296 // via: handle_parallel_super_load
297 // when resolving a class that has an existing placeholder with
298 // a saved superclass [i.e. a defineClass is currently in progress]
299 // if another thread is trying to resolve the class, it must do
300 // super-class checks on its own thread to catch class circularity
301 // This last call is critical in class circularity checking for cases
302 // where classloading is delegated to different threads and the
303 // classloader lock is released.
304 // Take the case: Base->Super->Base
305 // 1. If thread T1 tries to do a defineClass of class Base
306 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
307 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
308 // so it tries to load Super
309 // 3. If we load the class internally, or user classloader uses same thread
310 // loadClassFromxxx or defineClass via parseClassFile Super ...
311 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
312 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
313 // 3.4 calls resolve_super_or_fail Base
314 // 3.5 finds T1,Base -> throws class circularity
315 //OR 4. If T2 tries to resolve Super via defineClass Super ...
316 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
317 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
318 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
319 // 4.4 finds T2, Super -> throws class circularity
320 // Must be called, even if superclass is null, since this is
321 // where the placeholder entry is created which claims this
322 // thread is loading this class/classloader.
323 // Be careful when modifying this code: once you have run
324 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
325 // you need to find_and_remove it before returning.
326 // So be careful to not exit with a CHECK_ macro betweeen these calls.
327 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
328 Symbol* class_name,
329 Handle class_loader,
330 Handle protection_domain,
331 bool is_superclass,
332 TRAPS) {
333 #if INCLUDE_CDS
334 if (DumpSharedSpaces) {
335 // Special processing for CDS dump time.
336 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
337 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
338 if (k) {
339 return k;
340 }
341 }
342 #endif // INCLUDE_CDS
343
344 // Double-check, if child class is already loaded, just return super-class,interface
345 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
346 // dictionary.
347 // Make sure there's a placeholder for the *child* before resolving.
348 // Used as a claim that this thread is currently loading superclass/classloader
349 // Used here for ClassCircularity checks and also for heap verification
350 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
351 // Must check ClassCircularity before checking if super class is already loaded.
352 //
353 // We might not already have a placeholder if this child_name was
354 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
355 // the name of the class might not be known until the stream is actually
356 // parsed.
357 // Bugs 4643874, 4715493
358
359 ClassLoaderData* loader_data = class_loader_data(class_loader);
360 Dictionary* dictionary = loader_data->dictionary();
361 unsigned int d_hash = dictionary->compute_hash(child_name);
362 int d_index = dictionary->hash_to_index(d_hash);
363 unsigned int p_hash = placeholders()->compute_hash(child_name);
364 int p_index = placeholders()->hash_to_index(p_hash);
365 // can't throw error holding a lock
366 bool child_already_loaded = false;
367 bool throw_circularity_error = false;
368 {
369 MutexLocker mu(SystemDictionary_lock, THREAD);
370 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
371 Klass* quicksuperk;
372 // to support // loading: if child done loading, just return superclass
373 // if class_name, & class_loader don't match:
374 // if initial define, SD update will give LinkageError
375 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
376 // so we don't throw an exception here.
377 // see: nsk redefclass014 & java.lang.instrument Instrument032
378 if ((childk != NULL ) && (is_superclass) &&
379 ((quicksuperk = childk->super()) != NULL) &&
380
381 ((quicksuperk->name() == class_name) &&
382 (quicksuperk->class_loader() == class_loader()))) {
383 return quicksuperk;
384 } else {
385 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
386 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
387 throw_circularity_error = true;
388 }
389 }
390 if (!throw_circularity_error) {
391 // Be careful not to exit resolve_super
392 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
393 }
394 }
395 if (throw_circularity_error) {
396 ResourceMark rm(THREAD);
397 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
398 }
399
400 // java.lang.Object should have been found above
401 assert(class_name != NULL, "null super class for resolving");
402 // Resolve the super class or interface, check results on return
403 Klass* superk = SystemDictionary::resolve_or_null(class_name,
404 class_loader,
405 protection_domain,
406 THREAD);
407
408 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
409 // It is no longer necessary to keep the placeholder table alive until update_dictionary
410 // or error. GC used to walk the placeholder table as strong roots.
411 // The instanceKlass is kept alive because the class loader is on the stack,
412 // which keeps the loader_data alive, as well as all instanceKlasses in
413 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
414 {
415 MutexLocker mu(SystemDictionary_lock, THREAD);
416 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
417 SystemDictionary_lock->notify_all();
418 }
419 if (HAS_PENDING_EXCEPTION || superk == NULL) {
420 // can null superk
421 superk = handle_resolution_exception(class_name, true, superk, THREAD);
422 }
423
424 return superk;
425 }
426
427 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
428 Handle class_loader,
429 Handle protection_domain,
430 TRAPS) {
431 if(!has_checkPackageAccess()) return;
432
433 // Now we have to call back to java to check if the initating class has access
434 JavaValue result(T_VOID);
435 if (log_is_enabled(Debug, protectiondomain)) {
436 ResourceMark rm;
437 // Print out trace information
438 outputStream* log = Log(protectiondomain)::debug_stream();
439 log->print_cr("Checking package access");
440 log->print("class loader: "); class_loader()->print_value_on(log);
441 log->print(" protection domain: "); protection_domain()->print_value_on(log);
442 log->print(" loading: "); klass->print_value_on(log);
443 log->cr();
444 }
445
446 // This handle and the class_loader handle passed in keeps this class from
447 // being unloaded through several GC points.
448 // The class_loader handle passed in is the initiating loader.
449 Handle mirror(THREAD, klass->java_mirror());
450
451 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
452 JavaCalls::call_special(&result,
453 class_loader,
454 system_loader,
455 vmSymbols::checkPackageAccess_name(),
456 vmSymbols::class_protectiondomain_signature(),
457 mirror,
458 protection_domain,
459 THREAD);
460
461 if (HAS_PENDING_EXCEPTION) {
462 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
463 } else {
464 log_debug(protectiondomain)("granted");
465 }
466
467 if (HAS_PENDING_EXCEPTION) return;
468
469 // If no exception has been thrown, we have validated the protection domain
470 // Insert the protection domain of the initiating class into the set.
471 {
472 ClassLoaderData* loader_data = class_loader_data(class_loader);
473 Dictionary* dictionary = loader_data->dictionary();
474
475 Symbol* kn = klass->name();
476 unsigned int d_hash = dictionary->compute_hash(kn);
477 int d_index = dictionary->hash_to_index(d_hash);
478
479 MutexLocker mu(SystemDictionary_lock, THREAD);
480 dictionary->add_protection_domain(d_index, d_hash, klass,
481 protection_domain, THREAD);
482 }
483
484 // We only get here if this thread finds that another thread
485 // has already claimed the placeholder token for the current operation,
486 // but that other thread either never owned or gave up the
487 // object lock
488 // Waits on SystemDictionary_lock to indicate placeholder table updated
489 // On return, caller must recheck placeholder table state
490 //
491 // We only get here if
492 // 1) custom classLoader, i.e. not bootstrap classloader
493 // 2) UnsyncloadClass not set
494 // 3) custom classLoader has broken the class loader objectLock
495 // so another thread got here in parallel
496 //
497 // lockObject must be held.
498 // Complicated dance due to lock ordering:
499 // Must first release the classloader object lock to
500 // allow initial definer to complete the class definition
501 // and to avoid deadlock
502 // Reclaim classloader lock object with same original recursion count
503 // Must release SystemDictionary_lock after notify, since
504 // class loader lock must be claimed before SystemDictionary_lock
505 // to prevent deadlocks
506 //
507 // The notify allows applications that did an untimed wait() on
508 // the classloader object lock to not hang.
509 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
510 assert_lock_strong(SystemDictionary_lock);
511
512 bool calledholdinglock
513 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
514 assert(calledholdinglock,"must hold lock for notify");
515 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
516 ObjectSynchronizer::notifyall(lockObject, THREAD);
517 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
518 SystemDictionary_lock->wait();
519 SystemDictionary_lock->unlock();
520 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
521 SystemDictionary_lock->lock();
522 }
523
524 // If the class in is in the placeholder table, class loading is in progress
525 // For cases where the application changes threads to load classes, it
526 // is critical to ClassCircularity detection that we try loading
527 // the superclass on the same thread internally, so we do parallel
528 // super class loading here.
529 // This also is critical in cases where the original thread gets stalled
530 // even in non-circularity situations.
531 // Note: must call resolve_super_or_fail even if null super -
532 // to force placeholder entry creation for this class for circularity detection
533 // Caller must check for pending exception
534 // Returns non-null Klass* if other thread has completed load
535 // and we are done,
536 // If return null Klass* and no pending exception, the caller must load the class
537 InstanceKlass* SystemDictionary::handle_parallel_super_load(
538 Symbol* name, Symbol* superclassname, Handle class_loader,
539 Handle protection_domain, Handle lockObject, TRAPS) {
540
541 ClassLoaderData* loader_data = class_loader_data(class_loader);
542 Dictionary* dictionary = loader_data->dictionary();
543 unsigned int d_hash = dictionary->compute_hash(name);
544 int d_index = dictionary->hash_to_index(d_hash);
545 unsigned int p_hash = placeholders()->compute_hash(name);
546 int p_index = placeholders()->hash_to_index(p_hash);
547
548 // superk is not used, resolve_super called for circularity check only
549 // This code is reached in two situations. One if this thread
550 // is loading the same class twice (e.g. ClassCircularity, or
551 // java.lang.instrument).
552 // The second is if another thread started the resolve_super first
553 // and has not yet finished.
554 // In both cases the original caller will clean up the placeholder
555 // entry on error.
556 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
557 superclassname,
558 class_loader,
559 protection_domain,
560 true,
561 CHECK_NULL);
562
563 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
564 // Serial class loaders and bootstrap classloader do wait for superclass loads
565 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
566 MutexLocker mu(SystemDictionary_lock, THREAD);
567 // Check if classloading completed while we were loading superclass or waiting
568 return find_class(d_index, d_hash, name, dictionary);
569 }
570
571 // must loop to both handle other placeholder updates
572 // and spurious notifications
573 bool super_load_in_progress = true;
574 PlaceholderEntry* placeholder;
575 while (super_load_in_progress) {
576 MutexLocker mu(SystemDictionary_lock, THREAD);
577 // Check if classloading completed while we were loading superclass or waiting
578 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
579 if (check != NULL) {
580 // Klass is already loaded, so just return it
581 return check;
582 } else {
583 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
584 if (placeholder && placeholder->super_load_in_progress() ){
585 // Before UnsyncloadClass:
586 // We only get here if the application has released the
587 // classloader lock when another thread was in the middle of loading a
588 // superclass/superinterface for this class, and now
589 // this thread is also trying to load this class.
590 // To minimize surprises, the first thread that started to
591 // load a class should be the one to complete the loading
592 // with the classfile it initially expected.
593 // This logic has the current thread wait once it has done
594 // all the superclass/superinterface loading it can, until
595 // the original thread completes the class loading or fails
596 // If it completes we will use the resulting InstanceKlass
597 // which we will find below in the systemDictionary.
598 // We also get here for parallel bootstrap classloader
599 if (class_loader.is_null()) {
600 SystemDictionary_lock->wait();
601 } else {
602 double_lock_wait(lockObject, THREAD);
603 }
604 } else {
605 // If not in SD and not in PH, other thread's load must have failed
606 super_load_in_progress = false;
607 }
608 }
609 }
610 return NULL;
611 }
612
613 static void post_class_load_event(const Ticks& start_time,
614 InstanceKlass* k,
615 const ClassLoaderData* init_cld) {
616 #if INCLUDE_TRACE
617 EventClassLoad event(UNTIMED);
618 if (event.should_commit()) {
619 event.set_starttime(start_time);
620 event.set_loadedClass(k);
621 event.set_definingClassLoader(k->class_loader_data());
622 event.set_initiatingClassLoader(init_cld);
623 event.commit();
624 }
625 #endif // INCLUDE_TRACE
626 }
627
628 static void class_define_event(InstanceKlass* k,
629 const ClassLoaderData* def_cld) {
630 #if INCLUDE_TRACE
631 EventClassDefine event;
632 if (event.should_commit()) {
633 event.set_definedClass(k);
634 event.set_definingClassLoader(def_cld);
635 event.commit();
636 }
637 #endif // INCLUDE_TRACE
638 }
639
640 // Be careful when modifying this code: once you have run
641 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
642 // you need to find_and_remove it before returning.
643 // So be careful to not exit with a CHECK_ macro betweeen these calls.
644 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
645 Handle class_loader,
646 Handle protection_domain,
647 TRAPS) {
648 assert(name != NULL && !FieldType::is_array(name) &&
649 !FieldType::is_obj(name), "invalid class name");
650
651 Ticks class_load_start_time = Ticks::now();
652
653 HandleMark hm(THREAD);
654
655 // Fix for 4474172; see evaluation for more details
656 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
657 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
658 Dictionary* dictionary = loader_data->dictionary();
659
660 // Do lookup to see if class already exist and the protection domain
661 // has the right access
662 // This call uses find which checks protection domain already matches
663 // All subsequent calls use find_class, and set has_loaded_class so that
664 // before we return a result we call out to java to check for valid protection domain
665 // to allow returning the Klass* and add it to the pd_set if it is valid
666 unsigned int d_hash = dictionary->compute_hash(name);
667 int d_index = dictionary->hash_to_index(d_hash);
668 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
669 if (probe != NULL) return probe;
670
671
672 // Non-bootstrap class loaders will call out to class loader and
673 // define via jvm/jni_DefineClass which will acquire the
674 // class loader object lock to protect against multiple threads
675 // defining the class in parallel by accident.
676 // This lock must be acquired here so the waiter will find
677 // any successful result in the SystemDictionary and not attempt
678 // the define
679 // ParallelCapable Classloaders and the bootstrap classloader,
680 // or all classloaders with UnsyncloadClass do not acquire lock here
681 bool DoObjectLock = true;
682 if (is_parallelCapable(class_loader)) {
683 DoObjectLock = false;
684 }
685
686 unsigned int p_hash = placeholders()->compute_hash(name);
687 int p_index = placeholders()->hash_to_index(p_hash);
688
689 // Class is not in SystemDictionary so we have to do loading.
690 // Make sure we are synchronized on the class loader before we proceed
691 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
692 check_loader_lock_contention(lockObject, THREAD);
693 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
694
695 // Check again (after locking) if class already exist in SystemDictionary
696 bool class_has_been_loaded = false;
697 bool super_load_in_progress = false;
698 bool havesupername = false;
699 InstanceKlass* k = NULL;
700 PlaceholderEntry* placeholder;
701 Symbol* superclassname = NULL;
702
703 {
704 MutexLocker mu(SystemDictionary_lock, THREAD);
705 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
706 if (check != NULL) {
707 // Klass is already loaded, so just return it
708 class_has_been_loaded = true;
709 k = check;
710 } else {
711 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
712 if (placeholder && placeholder->super_load_in_progress()) {
713 super_load_in_progress = true;
714 if (placeholder->havesupername() == true) {
715 superclassname = placeholder->supername();
716 havesupername = true;
717 }
718 }
719 }
720 }
721
722 // If the class is in the placeholder table, class loading is in progress
723 if (super_load_in_progress && havesupername==true) {
724 k = handle_parallel_super_load(name,
725 superclassname,
726 class_loader,
727 protection_domain,
728 lockObject, THREAD);
729 if (HAS_PENDING_EXCEPTION) {
730 return NULL;
731 }
732 if (k != NULL) {
733 class_has_been_loaded = true;
734 }
735 }
736
737 bool throw_circularity_error = false;
738 if (!class_has_been_loaded) {
739 bool load_instance_added = false;
740
741 // add placeholder entry to record loading instance class
742 // Five cases:
743 // All cases need to prevent modifying bootclasssearchpath
744 // in parallel with a classload of same classname
745 // Redefineclasses uses existence of the placeholder for the duration
746 // of the class load to prevent concurrent redefinition of not completely
747 // defined classes.
748 // case 1. traditional classloaders that rely on the classloader object lock
749 // - no other need for LOAD_INSTANCE
750 // case 2. traditional classloaders that break the classloader object lock
751 // as a deadlock workaround. Detection of this case requires that
752 // this check is done while holding the classloader object lock,
753 // and that lock is still held when calling classloader's loadClass.
754 // For these classloaders, we ensure that the first requestor
755 // completes the load and other requestors wait for completion.
756 // case 3. UnsyncloadClass - don't use objectLocker
757 // With this flag, we allow parallel classloading of a
758 // class/classloader pair
759 // case4. Bootstrap classloader - don't own objectLocker
760 // This classloader supports parallelism at the classloader level,
761 // but only allows a single load of a class/classloader pair.
762 // No performance benefit and no deadlock issues.
763 // case 5. parallelCapable user level classloaders - without objectLocker
764 // Allow parallel classloading of a class/classloader pair
765
766 {
767 MutexLocker mu(SystemDictionary_lock, THREAD);
768 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
769 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
770 if (oldprobe) {
771 // only need check_seen_thread once, not on each loop
772 // 6341374 java/lang/Instrument with -Xcomp
773 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
774 throw_circularity_error = true;
775 } else {
776 // case 1: traditional: should never see load_in_progress.
777 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
778
779 // case 4: bootstrap classloader: prevent futile classloading,
780 // wait on first requestor
781 if (class_loader.is_null()) {
782 SystemDictionary_lock->wait();
783 } else {
784 // case 2: traditional with broken classloader lock. wait on first
785 // requestor.
786 double_lock_wait(lockObject, THREAD);
787 }
788 // Check if classloading completed while we were waiting
789 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
790 if (check != NULL) {
791 // Klass is already loaded, so just return it
792 k = check;
793 class_has_been_loaded = true;
794 }
795 // check if other thread failed to load and cleaned up
796 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
797 }
798 }
799 }
800 }
801 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
802 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
803 // LOAD_INSTANCE in parallel
804
805 if (!throw_circularity_error && !class_has_been_loaded) {
806 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
807 load_instance_added = true;
808 // For class loaders that do not acquire the classloader object lock,
809 // if they did not catch another thread holding LOAD_INSTANCE,
810 // need a check analogous to the acquire ObjectLocker/find_class
811 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
812 // one final check if the load has already completed
813 // class loaders holding the ObjectLock shouldn't find the class here
814 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
815 if (check != NULL) {
816 // Klass is already loaded, so return it after checking/adding protection domain
817 k = check;
818 class_has_been_loaded = true;
819 }
820 }
821 }
822
823 // must throw error outside of owning lock
824 if (throw_circularity_error) {
825 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
826 ResourceMark rm(THREAD);
827 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
828 }
829
830 if (!class_has_been_loaded) {
831
832 // Do actual loading
833 k = load_instance_class(name, class_loader, THREAD);
834
835 // For UnsyncloadClass only
836 // If they got a linkageError, check if a parallel class load succeeded.
837 // If it did, then for bytecode resolution the specification requires
838 // that we return the same result we did for the other thread, i.e. the
839 // successfully loaded InstanceKlass
840 // Should not get here for classloaders that support parallelism
841 // with the new cleaner mechanism, even with AllowParallelDefineClass
842 // Bootstrap goes through here to allow for an extra guarantee check
843 if (UnsyncloadClass || (class_loader.is_null())) {
844 if (k == NULL && HAS_PENDING_EXCEPTION
845 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
846 MutexLocker mu(SystemDictionary_lock, THREAD);
847 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
848 if (check != NULL) {
849 // Klass is already loaded, so just use it
850 k = check;
851 CLEAR_PENDING_EXCEPTION;
852 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
853 }
854 }
855 }
856
857 // If everything was OK (no exceptions, no null return value), and
858 // class_loader is NOT the defining loader, do a little more bookkeeping.
859 if (!HAS_PENDING_EXCEPTION && k != NULL &&
860 k->class_loader() != class_loader()) {
861
862 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
863
864 // Need to check for a PENDING_EXCEPTION again; check_constraints
865 // can throw and doesn't use the CHECK macro.
866 if (!HAS_PENDING_EXCEPTION) {
867 { // Grabbing the Compile_lock prevents systemDictionary updates
868 // during compilations.
869 MutexLocker mu(Compile_lock, THREAD);
870 update_dictionary(d_index, 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
897 post_class_load_event(class_load_start_time, k, loader_data);
898
899 #ifdef ASSERT
900 {
901 ClassLoaderData* loader_data = k->class_loader_data();
902 MutexLocker mu(SystemDictionary_lock, THREAD);
903 Klass* 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 {
913 MutexLocker mu(SystemDictionary_lock, THREAD);
914 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
915 protection_domain)) {
916 return k;
917 }
918 }
919
920 // Verify protection domain. If it fails an exception is thrown
921 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
922
923 return k;
924 }
925
926
927 // This routine does not lock the system dictionary.
928 //
929 // Since readers don't hold a lock, we must make sure that system
930 // dictionary entries are only removed at a safepoint (when only one
931 // thread is running), and are added to in a safe way (all links must
932 // be updated in an MT-safe manner).
933 //
934 // Callers should be aware that an entry could be added just after
935 // _dictionary->bucket(index) is read here, so the caller will not see
936 // the new entry.
937
938 Klass* SystemDictionary::find(Symbol* class_name,
939 Handle class_loader,
940 Handle protection_domain,
941 TRAPS) {
942
943 // The result of this call should be consistent with the result
944 // of the call to resolve_instance_class_or_null().
945 // See evaluation 6790209 and 4474172 for more details.
946 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
947 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
948
949 if (loader_data == NULL) {
950 // If the ClassLoaderData has not been setup,
951 // then the class loader has no entries in the dictionary.
952 return NULL;
953 }
954
955 Dictionary* dictionary = loader_data->dictionary();
956 unsigned int d_hash = dictionary->compute_hash(class_name);
957 int d_index = dictionary->hash_to_index(d_hash);
958 return dictionary->find(d_index, d_hash, class_name,
959 protection_domain);
960 }
961
962
963 // Look for a loaded instance or array klass by name. Do not do any loading.
964 // return NULL in case of error.
965 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
966 Handle class_loader,
967 Handle protection_domain,
968 TRAPS) {
969 Klass* k = NULL;
970 assert(class_name != NULL, "class name must be non NULL");
971
972 if (FieldType::is_array(class_name)) {
973 // The name refers to an array. Parse the name.
974 // dimension and object_key in FieldArrayInfo are assigned as a
975 // side-effect of this call
976 FieldArrayInfo fd;
977 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
978 if (t != T_OBJECT) {
979 k = Universe::typeArrayKlassObj(t);
980 } else {
981 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
982 }
983 if (k != NULL) {
984 k = k->array_klass_or_null(fd.dimension());
985 }
986 } else {
987 k = find(class_name, class_loader, protection_domain, THREAD);
988 }
989 return k;
990 }
991
992 // Note: this method is much like resolve_from_stream, but
993 // does not publish the classes via the SystemDictionary.
994 // Handles unsafe_DefineAnonymousClass and redefineclasses
995 // RedefinedClasses do not add to the class hierarchy
996 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
997 Handle class_loader,
998 Handle protection_domain,
999 ClassFileStream* st,
1000 const InstanceKlass* host_klass,
1001 GrowableArray<Handle>* cp_patches,
1002 TRAPS) {
1003
1004 Ticks class_load_start_time = Ticks::now();
1005
1006 ClassLoaderData* loader_data;
1007 if (host_klass != NULL) {
1008 // Create a new CLD for anonymous class, that uses the same class loader
1009 // as the host_klass
1010 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1011 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1012 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1013 } else {
1014 loader_data = ClassLoaderData::class_loader_data(class_loader());
1015 }
1016
1017 assert(st != NULL, "invariant");
1018 assert(st->need_verify(), "invariant");
1019
1020 // Parse stream and create a klass.
1021 // Note that we do this even though this klass might
1022 // already be present in the SystemDictionary, otherwise we would not
1023 // throw potential ClassFormatErrors.
1024
1025 InstanceKlass* k = KlassFactory::create_from_stream(st,
1026 class_name,
1027 loader_data,
1028 protection_domain,
1029 host_klass,
1030 cp_patches,
1031 CHECK_NULL);
1032
1033 if (host_klass != NULL && k != NULL) {
1034 // If it's anonymous, initialize it now, since nobody else will.
1035
1036 {
1037 MutexLocker mu_r(Compile_lock, THREAD);
1038
1039 // Add to class hierarchy, initialize vtables, and do possible
1040 // deoptimizations.
1041 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1042
1043 // But, do not add to dictionary.
1044
1045 // compiled code dependencies need to be validated anyway
1046 notice_modification();
1047 }
1048
1049 // Rewrite and patch constant pool here.
1050 k->link_class(CHECK_NULL);
1051 if (cp_patches != NULL) {
1052 k->constants()->patch_resolved_references(cp_patches);
1053 }
1054 k->eager_initialize(CHECK_NULL);
1055
1056 // notify jvmti
1057 if (JvmtiExport::should_post_class_load()) {
1058 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1059 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1060 }
1061
1062 post_class_load_event(class_load_start_time, k, loader_data);
1063 }
1064 assert(host_klass != NULL || NULL == cp_patches,
1065 "cp_patches only found with host_klass");
1066
1067 return k;
1068 }
1069
1070 // Add a klass to the system from a stream (called by jni_DefineClass and
1071 // JVM_DefineClass).
1072 // Note: class_name can be NULL. In that case we do not know the name of
1073 // the class until we have parsed the stream.
1074
1075 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1076 Handle class_loader,
1077 Handle protection_domain,
1078 ClassFileStream* st,
1079 TRAPS) {
1080
1081 HandleMark hm(THREAD);
1082
1083 // Classloaders that support parallelism, e.g. bootstrap classloader,
1084 // or all classloaders with UnsyncloadClass do not acquire lock here
1085 bool DoObjectLock = true;
1086 if (is_parallelCapable(class_loader)) {
1087 DoObjectLock = false;
1088 }
1089
1090 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1091
1092 // Make sure we are synchronized on the class loader before we proceed
1093 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1094 check_loader_lock_contention(lockObject, THREAD);
1095 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1096
1097 assert(st != NULL, "invariant");
1098
1099 // Parse the stream and create a klass.
1100 // Note that we do this even though this klass might
1101 // already be present in the SystemDictionary, otherwise we would not
1102 // throw potential ClassFormatErrors.
1103 InstanceKlass* k = NULL;
1104
1105 #if INCLUDE_CDS
1106 k = SystemDictionaryShared::lookup_from_stream(class_name,
1107 class_loader,
1108 protection_domain,
1109 st,
1110 CHECK_NULL);
1111 #endif
1112
1113 if (k == NULL) {
1114 if (st->buffer() == NULL) {
1115 return NULL;
1116 }
1117 k = KlassFactory::create_from_stream(st,
1118 class_name,
1119 loader_data,
1120 protection_domain,
1121 NULL, // host_klass
1122 NULL, // cp_patches
1123 CHECK_NULL);
1124 }
1125
1126 assert(k != NULL, "no klass created");
1127 Symbol* h_name = k->name();
1128 assert(class_name == NULL || class_name == h_name, "name mismatch");
1129
1130 // Add class just loaded
1131 // If a class loader supports parallel classloading handle parallel define requests
1132 // find_or_define_instance_class may return a different InstanceKlass
1133 if (is_parallelCapable(class_loader)) {
1134 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1135 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1136 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1137 assert(defined_k != NULL, "Should have a klass if there's no exception");
1138 loader_data->add_to_deallocate_list(k);
1139 k = defined_k;
1140 }
1141 } else {
1142 define_instance_class(k, THREAD);
1143 }
1144
1145 // If defining the class throws an exception register 'k' for cleanup.
1146 if (HAS_PENDING_EXCEPTION) {
1147 assert(k != NULL, "Must have an instance klass here!");
1148 loader_data->add_to_deallocate_list(k);
1149 return NULL;
1150 }
1151
1152 // Make sure we have an entry in the SystemDictionary on success
1153 debug_only( {
1154 MutexLocker mu(SystemDictionary_lock, THREAD);
1155
1156 Klass* check = find_class(h_name, k->class_loader_data());
1157 assert(check == k, "should be present in the dictionary");
1158 } );
1159
1160 return k;
1161 }
1162
1163 #if INCLUDE_CDS
1164 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1165 int number_of_entries) {
1166 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1167 "bad shared dictionary size.");
1168 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1169 _shared_dictionary_size, t, number_of_entries);
1170 }
1171
1172
1173 // If there is a shared dictionary, then find the entry for the
1174 // given shared system class, if any.
1175
1176 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1177 if (shared_dictionary() != NULL) {
1178 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1179 int d_index = shared_dictionary()->hash_to_index(d_hash);
1180
1181 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1182 } else {
1183 return NULL;
1184 }
1185 }
1186
1187
1188 // Load a class from the shared spaces (found through the shared system
1189 // dictionary). Force the superclass and all interfaces to be loaded.
1190 // Update the class definition to include sibling classes and no
1191 // subclasses (yet). [Classes in the shared space are not part of the
1192 // object hierarchy until loaded.]
1193
1194 InstanceKlass* SystemDictionary::load_shared_class(
1195 Symbol* class_name, Handle class_loader, TRAPS) {
1196 InstanceKlass* ik = find_shared_class(class_name);
1197 // Make sure we only return the boot class for the NULL classloader.
1198 if (ik != NULL &&
1199 ik->is_shared_boot_class() && class_loader.is_null()) {
1200 Handle protection_domain;
1201 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1202 }
1203 return NULL;
1204 }
1205
1206 // Check if a shared class can be loaded by the specific classloader:
1207 //
1208 // NULL classloader:
1209 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1210 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1211 // be defined in an unnamed module.
1212 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1213 InstanceKlass* ik,
1214 Handle class_loader, TRAPS) {
1215 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1216 "Cannot use sharing if java.base is patched");
1217 ResourceMark rm;
1218 int path_index = ik->shared_classpath_index();
1219 SharedClassPathEntry* ent =
1220 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1221 if (!Universe::is_module_initialized()) {
1222 assert(ent != NULL && ent->is_jrt(),
1223 "Loading non-bootstrap classes before the module system is initialized");
1224 assert(class_loader.is_null(), "sanity");
1225 return true;
1226 }
1227 // Get the pkg_entry from the classloader
1228 TempNewSymbol pkg_name = NULL;
1229 PackageEntry* pkg_entry = NULL;
1230 ModuleEntry* mod_entry = NULL;
1231 const char* pkg_string = NULL;
1232 ClassLoaderData* loader_data = class_loader_data(class_loader);
1233 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1234 if (pkg_name != NULL) {
1235 pkg_string = pkg_name->as_C_string();
1236 if (loader_data != NULL) {
1237 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1238 }
1239 if (pkg_entry != NULL) {
1240 mod_entry = pkg_entry->module();
1241 }
1242 }
1243
1244 // If the archived class is from a module that has been patched at runtime,
1245 // the class cannot be loaded from the archive.
1246 if (mod_entry != NULL && mod_entry->is_patched()) {
1247 return false;
1248 }
1249
1250 if (class_loader.is_null()) {
1251 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1252 // The NULL classloader can load archived class originated from the
1253 // "modules" jimage and the -Xbootclasspath/a. For class from the
1254 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1255 // by the NULL classloader.
1256 if (mod_entry != NULL) {
1257 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1258 // ModuleEntry's location agrees with the archived class' origination.
1259 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1260 return true; // Module class from the "module" jimage
1261 }
1262 }
1263
1264 // If the archived class is not from the "module" jimage, the class can be
1265 // loaded by the NULL classloader if
1266 //
1267 // 1. the class is from the unamed package
1268 // 2. or, the class is not from a module defined in the NULL classloader
1269 // 3. or, the class is from an unamed module
1270 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1271 // the class is from the -Xbootclasspath/a
1272 if (pkg_string == NULL ||
1273 pkg_entry == NULL ||
1274 pkg_entry->in_unnamed_module()) {
1275 assert(mod_entry == NULL ||
1276 mod_entry == loader_data->unnamed_module(),
1277 "the unnamed module is not defined in the classloader");
1278 return true;
1279 }
1280 }
1281 return false;
1282 } else {
1283 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1284 ik, class_loader, pkg_string, pkg_name,
1285 pkg_entry, mod_entry, CHECK_(false));
1286 return res;
1287 }
1288 }
1289
1290 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1291 Handle class_loader,
1292 Handle protection_domain, TRAPS) {
1293
1294 if (ik != NULL) {
1295 Symbol* class_name = ik->name();
1296
1297 bool visible = is_shared_class_visible(
1298 class_name, ik, class_loader, CHECK_NULL);
1299 if (!visible) {
1300 return NULL;
1301 }
1302
1303 // Resolve the superclass and interfaces. They must be the same
1304 // as in dump time, because the layout of <ik> depends on
1305 // the specific layout of ik->super() and ik->local_interfaces().
1306 //
1307 // If unexpected superclass or interfaces are found, we cannot
1308 // load <ik> from the shared archive.
1309
1310 if (ik->super() != NULL) {
1311 Symbol* cn = ik->super()->name();
1312 Klass *s = resolve_super_or_fail(class_name, cn,
1313 class_loader, protection_domain, true, CHECK_NULL);
1314 if (s != ik->super()) {
1315 // The dynamically resolved super class is not the same as the one we used during dump time,
1316 // so we cannot use ik.
1317 return NULL;
1318 } else {
1319 assert(s->is_shared(), "must be");
1320 }
1321 }
1322
1323 Array<Klass*>* interfaces = ik->local_interfaces();
1324 int num_interfaces = interfaces->length();
1325 for (int index = 0; index < num_interfaces; index++) {
1326 Klass* k = interfaces->at(index);
1327 Symbol* name = k->name();
1328 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1329 if (k != i) {
1330 // The dynamically resolved interface class is not the same as the one we used during dump time,
1331 // so we cannot use ik.
1332 return NULL;
1333 } else {
1334 assert(i->is_shared(), "must be");
1335 }
1336 }
1337
1338 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1339 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1340 if (new_ik != NULL) {
1341 // The class is changed by CFLH. Return the new class. The shared class is
1342 // not used.
1343 return new_ik;
1344 }
1345
1346 // Adjust methods to recover missing data. They need addresses for
1347 // interpreter entry points and their default native method address
1348 // must be reset.
1349
1350 // Updating methods must be done under a lock so multiple
1351 // threads don't update these in parallel
1352 //
1353 // Shared classes are all currently loaded by either the bootstrap or
1354 // internal parallel class loaders, so this will never cause a deadlock
1355 // on a custom class loader lock.
1356
1357 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1358 {
1359 HandleMark hm(THREAD);
1360 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1361 check_loader_lock_contention(lockObject, THREAD);
1362 ObjectLocker ol(lockObject, THREAD, true);
1363 // prohibited package check assumes all classes loaded from archive call
1364 // restore_unshareable_info which calls ik->set_package()
1365 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1366 }
1367
1368 ik->print_class_load_logging(loader_data, NULL, NULL);
1369
1370 // For boot loader, ensure that GetSystemPackage knows that a class in this
1371 // package was loaded.
1372 if (class_loader.is_null()) {
1373 int path_index = ik->shared_classpath_index();
1374 ResourceMark rm;
1375 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1376 }
1377
1378 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1379 // Only dump the classes that can be stored into CDS archive
1380 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1381 ResourceMark rm(THREAD);
1382 classlist_file->print_cr("%s", ik->name()->as_C_string());
1383 classlist_file->flush();
1384 }
1385 }
1386
1387 // notify a class loaded from shared object
1388 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1389 }
1390
1391 ik->set_has_passed_fingerprint_check(false);
1392 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1393 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1394 uint64_t cds_fp = ik->get_stored_fingerprint();
1395 if (aot_fp != 0 && aot_fp == cds_fp) {
1396 // This class matches with a class saved in an AOT library
1397 ik->set_has_passed_fingerprint_check(true);
1398 } else {
1399 ResourceMark rm;
1400 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1401 }
1402 }
1403 return ik;
1404 }
1405 #endif // INCLUDE_CDS
1406
1407 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1408
1409 if (class_loader.is_null()) {
1410 ResourceMark rm;
1411 PackageEntry* pkg_entry = NULL;
1412 bool search_only_bootloader_append = false;
1413 ClassLoaderData *loader_data = class_loader_data(class_loader);
1414
1415 // Find the package in the boot loader's package entry table.
1416 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1417 if (pkg_name != NULL) {
1418 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1419 }
1420
1421 // Prior to attempting to load the class, enforce the boot loader's
1422 // visibility boundaries.
1423 if (!Universe::is_module_initialized()) {
1424 // During bootstrapping, prior to module initialization, any
1425 // class attempting to be loaded must be checked against the
1426 // java.base packages in the boot loader's PackageEntryTable.
1427 // No class outside of java.base is allowed to be loaded during
1428 // this bootstrapping window.
1429 if (!DumpSharedSpaces) {
1430 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1431 // Class is either in the unnamed package or in
1432 // a named package within the unnamed module. Either
1433 // case is outside of java.base, do not attempt to
1434 // load the class post java.base definition. If
1435 // java.base has not been defined, let the class load
1436 // and its package will be checked later by
1437 // ModuleEntryTable::verify_javabase_packages.
1438 if (ModuleEntryTable::javabase_defined()) {
1439 return NULL;
1440 }
1441 } else {
1442 // Check that the class' package is defined within java.base.
1443 ModuleEntry* mod_entry = pkg_entry->module();
1444 Symbol* mod_entry_name = mod_entry->name();
1445 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1446 return NULL;
1447 }
1448 }
1449 }
1450 } else {
1451 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1452 // After the module system has been initialized, check if the class'
1453 // package is in a module defined to the boot loader.
1454 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1455 // Class is either in the unnamed package, in a named package
1456 // within a module not defined to the boot loader or in a
1457 // a named package within the unnamed module. In all cases,
1458 // limit visibility to search for the class only in the boot
1459 // loader's append path.
1460 search_only_bootloader_append = true;
1461 }
1462 }
1463
1464 // Prior to bootstrapping's module initialization, never load a class outside
1465 // of the boot loader's module path
1466 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1467 !search_only_bootloader_append,
1468 "Attempt to load a class outside of boot loader's module path");
1469
1470 // Search the shared system dictionary for classes preloaded into the
1471 // shared spaces.
1472 InstanceKlass* k = NULL;
1473 {
1474 #if INCLUDE_CDS
1475 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1476 k = load_shared_class(class_name, class_loader, THREAD);
1477 #endif
1478 }
1479
1480 if (k == NULL) {
1481 // Use VM class loader
1482 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1483 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1484 }
1485
1486 // find_or_define_instance_class may return a different InstanceKlass
1487 if (k != NULL) {
1488 InstanceKlass* defined_k =
1489 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1490 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1491 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1492 assert(defined_k != NULL, "Should have a klass if there's no exception");
1493 loader_data->add_to_deallocate_list(k);
1494 k = defined_k;
1495 } else if (HAS_PENDING_EXCEPTION) {
1496 loader_data->add_to_deallocate_list(k);
1497 return NULL;
1498 }
1499 }
1500 return k;
1501 } else {
1502 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1503 ResourceMark rm(THREAD);
1504
1505 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1506 JavaThread* jt = (JavaThread*) THREAD;
1507
1508 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1509 ClassLoader::perf_app_classload_selftime(),
1510 ClassLoader::perf_app_classload_count(),
1511 jt->get_thread_stat()->perf_recursion_counts_addr(),
1512 jt->get_thread_stat()->perf_timers_addr(),
1513 PerfClassTraceTime::CLASS_LOAD);
1514
1515 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1516 // Translate to external class name format, i.e., convert '/' chars to '.'
1517 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1518
1519 JavaValue result(T_OBJECT);
1520
1521 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1522
1523 // Call public unsynchronized loadClass(String) directly for all class loaders
1524 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1525 // acquire a class-name based lock rather than the class loader object lock.
1526 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1527 // so the call to loadClassInternal() was not required.
1528 //
1529 // UnsyncloadClass flag means both call loadClass(String) and do
1530 // not acquire the class loader lock even for class loaders that are
1531 // not parallelCapable. This was a risky transitional
1532 // flag for diagnostic purposes only. It is risky to call
1533 // custom class loaders without synchronization.
1534 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1535 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1536 // Do NOT assume this will be supported in future releases.
1537 //
1538 // Added MustCallLoadClassInternal in case we discover in the field
1539 // a customer that counts on this call
1540 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1541 JavaCalls::call_special(&result,
1542 class_loader,
1543 spec_klass,
1544 vmSymbols::loadClassInternal_name(),
1545 vmSymbols::string_class_signature(),
1546 string,
1547 CHECK_NULL);
1548 } else {
1549 JavaCalls::call_virtual(&result,
1550 class_loader,
1551 spec_klass,
1552 vmSymbols::loadClass_name(),
1553 vmSymbols::string_class_signature(),
1554 string,
1555 CHECK_NULL);
1556 }
1557
1558 assert(result.get_type() == T_OBJECT, "just checking");
1559 oop obj = (oop) result.get_jobject();
1560
1561 // Primitive classes return null since forName() can not be
1562 // used to obtain any of the Class objects representing primitives or void
1563 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1564 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1565 // For user defined Java class loaders, check that the name returned is
1566 // the same as that requested. This check is done for the bootstrap
1567 // loader when parsing the class file.
1568 if (class_name == k->name()) {
1569 return k;
1570 }
1571 }
1572 // Class is not found or has the wrong name, return NULL
1573 return NULL;
1574 }
1575 }
1576
1577 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1578
1579 HandleMark hm(THREAD);
1580 ClassLoaderData* loader_data = k->class_loader_data();
1581 Handle class_loader_h(THREAD, loader_data->class_loader());
1582
1583 // for bootstrap and other parallel classloaders don't acquire lock,
1584 // use placeholder token
1585 // If a parallelCapable class loader calls define_instance_class instead of
1586 // find_or_define_instance_class to get here, we have a timing
1587 // hole with systemDictionary updates and check_constraints
1588 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1589 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1590 compute_loader_lock_object(class_loader_h, THREAD)),
1591 "define called without lock");
1592 }
1593
1594 // Check class-loading constraints. Throw exception if violation is detected.
1595 // Grabs and releases SystemDictionary_lock
1596 // The check_constraints/find_class call and update_dictionary sequence
1597 // must be "atomic" for a specific class/classloader pair so we never
1598 // define two different instanceKlasses for that class/classloader pair.
1599 // Existing classloaders will call define_instance_class with the
1600 // classloader lock held
1601 // Parallel classloaders will call find_or_define_instance_class
1602 // which will require a token to perform the define class
1603 Symbol* name_h = k->name();
1604 Dictionary* dictionary = loader_data->dictionary();
1605 unsigned int d_hash = dictionary->compute_hash(name_h);
1606 int d_index = dictionary->hash_to_index(d_hash);
1607 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1608
1609 // Register class just loaded with class loader (placed in Vector)
1610 // Note we do this before updating the dictionary, as this can
1611 // fail with an OutOfMemoryError (if it does, we will *not* put this
1612 // class in the dictionary and will not update the class hierarchy).
1613 // JVMTI FollowReferences needs to find the classes this way.
1614 if (k->class_loader() != NULL) {
1615 methodHandle m(THREAD, Universe::loader_addClass_method());
1616 JavaValue result(T_VOID);
1617 JavaCallArguments args(class_loader_h);
1618 args.push_oop(Handle(THREAD, k->java_mirror()));
1619 JavaCalls::call(&result, m, &args, CHECK);
1620 }
1621
1622 // Add the new class. We need recompile lock during update of CHA.
1623 {
1624 unsigned int p_hash = placeholders()->compute_hash(name_h);
1625 int p_index = placeholders()->hash_to_index(p_hash);
1626
1627 MutexLocker mu_r(Compile_lock, THREAD);
1628
1629 // Add to class hierarchy, initialize vtables, and do possible
1630 // deoptimizations.
1631 add_to_hierarchy(k, CHECK); // No exception, but can block
1632
1633 // Add to systemDictionary - so other classes can see it.
1634 // Grabs and releases SystemDictionary_lock
1635 update_dictionary(d_index, d_hash, p_index, p_hash,
1636 k, class_loader_h, THREAD);
1637 }
1638 k->eager_initialize(THREAD);
1639
1640 // notify jvmti
1641 if (JvmtiExport::should_post_class_load()) {
1642 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1643 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1644
1645 }
1646 class_define_event(k, loader_data);
1647 }
1648
1649 // Support parallel classloading
1650 // All parallel class loaders, including bootstrap classloader
1651 // lock a placeholder entry for this class/class_loader pair
1652 // to allow parallel defines of different classes for this class loader
1653 // With AllowParallelDefine flag==true, in case they do not synchronize around
1654 // FindLoadedClass/DefineClass, calls, we check for parallel
1655 // loading for them, wait if a defineClass is in progress
1656 // and return the initial requestor's results
1657 // This flag does not apply to the bootstrap classloader.
1658 // With AllowParallelDefine flag==false, call through to define_instance_class
1659 // which will throw LinkageError: duplicate class definition.
1660 // False is the requested default.
1661 // For better performance, the class loaders should synchronize
1662 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1663 // potentially waste time reading and parsing the bytestream.
1664 // Note: VM callers should ensure consistency of k/class_name,class_loader
1665 // Be careful when modifying this code: once you have run
1666 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1667 // you need to find_and_remove it before returning.
1668 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1669 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1670 InstanceKlass* k, TRAPS) {
1671
1672 Symbol* name_h = k->name(); // passed in class_name may be null
1673 ClassLoaderData* loader_data = class_loader_data(class_loader);
1674 Dictionary* dictionary = loader_data->dictionary();
1675
1676 unsigned int d_hash = dictionary->compute_hash(name_h);
1677 int d_index = dictionary->hash_to_index(d_hash);
1678
1679 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1680 unsigned int p_hash = placeholders()->compute_hash(name_h);
1681 int p_index = placeholders()->hash_to_index(p_hash);
1682 PlaceholderEntry* probe;
1683
1684 {
1685 MutexLocker mu(SystemDictionary_lock, THREAD);
1686 // First check if class already defined
1687 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1688 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1689 if (check != NULL) {
1690 return check;
1691 }
1692 }
1693
1694 // Acquire define token for this class/classloader
1695 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1696 // Wait if another thread defining in parallel
1697 // All threads wait - even those that will throw duplicate class: otherwise
1698 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1699 // if other thread has not finished updating dictionary
1700 while (probe->definer() != NULL) {
1701 SystemDictionary_lock->wait();
1702 }
1703 // Only special cases allow parallel defines and can use other thread's results
1704 // Other cases fall through, and may run into duplicate defines
1705 // caught by finding an entry in the SystemDictionary
1706 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1707 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1708 SystemDictionary_lock->notify_all();
1709 #ifdef ASSERT
1710 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1711 assert(check != NULL, "definer missed recording success");
1712 #endif
1713 return probe->instance_klass();
1714 } else {
1715 // This thread will define the class (even if earlier thread tried and had an error)
1716 probe->set_definer(THREAD);
1717 }
1718 }
1719
1720 define_instance_class(k, THREAD);
1721
1722 Handle linkage_exception = Handle(); // null handle
1723
1724 // definer must notify any waiting threads
1725 {
1726 MutexLocker mu(SystemDictionary_lock, THREAD);
1727 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1728 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1729 if (probe != NULL) {
1730 if (HAS_PENDING_EXCEPTION) {
1731 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1732 CLEAR_PENDING_EXCEPTION;
1733 } else {
1734 probe->set_instance_klass(k);
1735 }
1736 probe->set_definer(NULL);
1737 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1738 SystemDictionary_lock->notify_all();
1739 }
1740 }
1741
1742 // Can't throw exception while holding lock due to rank ordering
1743 if (linkage_exception() != NULL) {
1744 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1745 }
1746
1747 return k;
1748 }
1749
1750 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1751 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1752 if (class_loader.is_null()) {
1753 return Handle(THREAD, _system_loader_lock_obj);
1754 } else {
1755 return class_loader;
1756 }
1757 }
1758
1759 // This method is added to check how often we have to wait to grab loader
1760 // lock. The results are being recorded in the performance counters defined in
1761 // ClassLoader::_sync_systemLoaderLockContentionRate and
1762 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1763 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1764 if (!UsePerfData) {
1765 return;
1766 }
1767
1768 assert(!loader_lock.is_null(), "NULL lock object");
1769
1770 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1771 == ObjectSynchronizer::owner_other) {
1772 // contention will likely happen, so increment the corresponding
1773 // contention counter.
1774 if (loader_lock() == _system_loader_lock_obj) {
1775 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1776 } else {
1777 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1778 }
1779 }
1780 }
1781
1782 // ----------------------------------------------------------------------------
1783 // Lookup
1784
1785 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1786 Symbol* class_name,
1787 Dictionary* dictionary) {
1788 assert_locked_or_safepoint(SystemDictionary_lock);
1789 return dictionary->find_class(index, hash, class_name);
1790 }
1791
1792
1793 // Basic find on classes in the midst of being loaded
1794 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1795 ClassLoaderData* loader_data) {
1796 assert_locked_or_safepoint(SystemDictionary_lock);
1797 unsigned int p_hash = placeholders()->compute_hash(class_name);
1798 int p_index = placeholders()->hash_to_index(p_hash);
1799 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1800 }
1801
1802
1803 // Used for assertions and verification only
1804 // Precalculating the hash and index is an optimization because there are many lookups
1805 // before adding the class.
1806 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1807 assert_locked_or_safepoint(SystemDictionary_lock);
1808 #ifndef ASSERT
1809 guarantee(VerifyBeforeGC ||
1810 VerifyDuringGC ||
1811 VerifyBeforeExit ||
1812 VerifyDuringStartup ||
1813 VerifyAfterGC, "too expensive");
1814 #endif
1815
1816 Dictionary* dictionary = loader_data->dictionary();
1817 unsigned int d_hash = dictionary->compute_hash(class_name);
1818 int d_index = dictionary->hash_to_index(d_hash);
1819 return find_class(d_index, d_hash, class_name, dictionary);
1820 }
1821
1822
1823 // ----------------------------------------------------------------------------
1824 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1825 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1826 // before a new class is used.
1827
1828 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1829 assert(k != NULL, "just checking");
1830 assert_locked_or_safepoint(Compile_lock);
1831
1832 // Link into hierachy. Make sure the vtables are initialized before linking into
1833 k->append_to_sibling_list(); // add to superklass/sibling list
1834 k->process_interfaces(THREAD); // handle all "implements" declarations
1835 k->set_init_state(InstanceKlass::loaded);
1836 // Now flush all code that depended on old class hierarchy.
1837 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1838 // Also, first reinitialize vtable because it may have gotten out of synch
1839 // while the new class wasn't connected to the class hierarchy.
1840 CodeCache::flush_dependents_on(k);
1841 }
1842
1843 // ----------------------------------------------------------------------------
1844 // GC support
1845
1846 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1847 roots_oops_do(blk, NULL);
1848 }
1849
1850
1851 #ifdef ASSERT
1852 class VerifySDReachableAndLiveClosure : public OopClosure {
1853 private:
1854 BoolObjectClosure* _is_alive;
1855
1856 template <class T> void do_oop_work(T* p) {
1857 oop obj = oopDesc::load_decode_heap_oop(p);
1858 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1859 }
1860
1861 public:
1862 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1863
1864 virtual void do_oop(oop* p) { do_oop_work(p); }
1865 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1866 };
1867 #endif
1868
1869 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1870 // Note: anonymous classes are not in the SD.
1871 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1872 GCTimer* gc_timer,
1873 bool do_cleaning) {
1874
1875
1876 bool unloading_occurred;
1877 {
1878 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1879
1880 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1881 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1882 do_cleaning);
1883 }
1884
1885 if (unloading_occurred) {
1886 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1887 constraints()->purge_loader_constraints();
1888 resolution_errors()->purge_resolution_errors();
1889 }
1890
1891 {
1892 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1893 // Oops referenced by the protection domain cache table may get unreachable independently
1894 // of the class loader (eg. cached protection domain oops). So we need to
1895 // explicitly unlink them here.
1896 _pd_cache_table->unlink(is_alive);
1897
1898 #ifdef ASSERT
1899 VerifySDReachableAndLiveClosure cl(is_alive);
1900 _pd_cache_table->oops_do(&cl);
1901 #endif
1902 }
1903
1904 if (do_cleaning) {
1905 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1906 ResolvedMethodTable::unlink(is_alive);
1907 }
1908
1909 return unloading_occurred;
1910 }
1911
1912 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1913 strong->do_oop(&_java_system_loader);
1914 strong->do_oop(&_system_loader_lock_obj);
1915 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1916
1917 // Do strong roots marking if the closures are the same.
1918 if (strong == weak || !ClassUnloading) {
1919 // Only the protection domain oops contain references into the heap. Iterate
1920 // over all of them.
1921 _pd_cache_table->oops_do(strong);
1922 } else {
1923 if (weak != NULL) {
1924 _pd_cache_table->oops_do(weak);
1925 }
1926 }
1927
1928 // Visit extra methods
1929 invoke_method_table()->oops_do(strong);
1930
1931 if (weak != NULL) {
1932 ResolvedMethodTable::oops_do(weak);
1933 }
1934 }
1935
1936 void SystemDictionary::oops_do(OopClosure* f) {
1937 f->do_oop(&_java_system_loader);
1938 f->do_oop(&_system_loader_lock_obj);
1939 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1940
1941 // Only the protection domain oops contain references into the heap. Iterate
1942 // over all of them.
1943 _pd_cache_table->oops_do(f);
1944
1945 // Visit extra methods
1946 invoke_method_table()->oops_do(f);
1947
1948 ResolvedMethodTable::oops_do(f);
1949 }
1950
1951 void SystemDictionary::methods_do(void f(Method*)) {
1952 // Walk methods in loaded classes
1953 ClassLoaderDataGraph::methods_do(f);
1954 // Walk method handle intrinsics
1955 invoke_method_table()->methods_do(f);
1956 }
1957
1958 void SystemDictionary::remove_classes_in_error_state() {
1959 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1960 }
1961
1962 // ----------------------------------------------------------------------------
1963 // Lazily load klasses
1964
1965 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1966 // if multiple threads calling this function, only one thread will load
1967 // the class. The other threads will find the loaded version once the
1968 // class is loaded.
1969 Klass* aos = _abstract_ownable_synchronizer_klass;
1970 if (aos == NULL) {
1971 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1972 // Force a fence to prevent any read before the write completes
1973 OrderAccess::fence();
1974 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1975 }
1976 }
1977
1978 // ----------------------------------------------------------------------------
1979 // Initialization
1980
1981 void SystemDictionary::initialize(TRAPS) {
1982 // Allocate arrays
1983 _placeholders = new PlaceholderTable(_placeholder_table_size);
1984 _number_of_modifications = 0;
1985 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1986 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1987 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1988 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1989
1990 // Allocate private object used as system class loader lock
1991 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1992 // Initialize basic classes
1993 initialize_preloaded_classes(CHECK);
1994 }
1995
1996 // Compact table of directions on the initialization of klasses:
1997 static const short wk_init_info[] = {
1998 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1999 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2000 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2001 | (int)SystemDictionary::option ),
2002 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2003 #undef WK_KLASS_INIT_INFO
2004 0
2005 };
2006
2007 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2008 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2009 int info = wk_init_info[id - FIRST_WKID];
2010 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2011 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2012 InstanceKlass** klassp = &_well_known_klasses[id];
2013
2014 bool must_load;
2015 #if INCLUDE_JVMCI
2016 if (EnableJVMCI) {
2017 // If JVMCI is enabled we require its classes to be found.
2018 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2019 } else
2020 #endif
2021 {
2022 must_load = (init_opt < SystemDictionary::Opt);
2023 }
2024
2025 if ((*klassp) == NULL) {
2026 Klass* k;
2027 if (must_load) {
2028 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2029 } else {
2030 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2031 }
2032 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2033 }
2034 return ((*klassp) != NULL);
2035 }
2036
2037 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2038 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2039 for (int id = (int)start_id; id < (int)limit_id; id++) {
2040 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2041 int info = wk_init_info[id - FIRST_WKID];
2042 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2043 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2044
2045 initialize_wk_klass((WKID)id, opt, CHECK);
2046 }
2047
2048 // move the starting value forward to the limit:
2049 start_id = limit_id;
2050 }
2051
2052 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2053 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2054
2055 // Create the ModuleEntry for java.base. This call needs to be done here,
2056 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2057 ClassLoader::classLoader_init2(CHECK);
2058
2059 // Preload commonly used klasses
2060 WKID scan = FIRST_WKID;
2061 // first do Object, then String, Class
2062 #if INCLUDE_CDS
2063 if (UseSharedSpaces) {
2064 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2065 // Initialize the constant pool for the Object_class
2066 Object_klass()->constants()->restore_unshareable_info(CHECK);
2067 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2068 } else
2069 #endif
2070 {
2071 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2072 }
2073
2074 // Calculate offsets for String and Class classes since they are loaded and
2075 // can be used after this point.
2076 java_lang_String::compute_offsets();
2077 java_lang_Class::compute_offsets();
2078
2079 // Fixup mirrors for classes loaded before java.lang.Class.
2080 // These calls iterate over the objects currently in the perm gen
2081 // so calling them at this point is matters (not before when there
2082 // are fewer objects and not later after there are more objects
2083 // in the perm gen.
2084 Universe::initialize_basic_type_mirrors(CHECK);
2085 Universe::fixup_mirrors(CHECK);
2086
2087 // do a bunch more:
2088 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2089
2090 // Preload ref klasses and set reference types
2091 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2092 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2093
2094 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2095 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2096 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2097 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2098 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2099
2100 // JSR 292 classes
2101 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2102 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2103 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2104 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2105 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2106
2107 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2108 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2109 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2110 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2111 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2112 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2113 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2114 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2115 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2116 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2117
2118 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2119 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2120 _has_loadClassInternal = (method != NULL);
2121 }
2122 { // Compute whether we should use checkPackageAccess or NOT
2123 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2124 _has_checkPackageAccess = (method != NULL);
2125 }
2126 }
2127
2128 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2129 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2130 BasicType SystemDictionary::box_klass_type(Klass* k) {
2131 assert(k != NULL, "");
2132 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2133 if (_box_klasses[i] == k)
2134 return (BasicType)i;
2135 }
2136 return T_OBJECT;
2137 }
2138
2139 // Constraints on class loaders. The details of the algorithm can be
2140 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2141 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2142 // that the dictionary needs to maintain a set of contraints that
2143 // must be satisfied by all classes in the dictionary.
2144 // if defining is true, then LinkageError if already in dictionary
2145 // if initiating loader, then ok if InstanceKlass matches existing entry
2146
2147 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2148 InstanceKlass* k,
2149 Handle class_loader, bool defining,
2150 TRAPS) {
2151 const char *linkage_error1 = NULL;
2152 const char *linkage_error2 = NULL;
2153 {
2154 Symbol* name = k->name();
2155 ClassLoaderData *loader_data = class_loader_data(class_loader);
2156
2157 MutexLocker mu(SystemDictionary_lock, THREAD);
2158
2159 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2160 if (check != NULL) {
2161 // if different InstanceKlass - duplicate class definition,
2162 // else - ok, class loaded by a different thread in parallel,
2163 // we should only have found it if it was done loading and ok to use
2164 // dictionary only holds instance classes, placeholders
2165 // also holds array classes
2166
2167 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2168 if ((defining == true) || (k != check)) {
2169 linkage_error1 = "loader (instance of ";
2170 linkage_error2 = "): attempted duplicate class definition for name: \"";
2171 } else {
2172 return;
2173 }
2174 }
2175
2176 #ifdef ASSERT
2177 Symbol* ph_check = find_placeholder(name, loader_data);
2178 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2179 #endif
2180
2181 if (linkage_error1 == NULL) {
2182 if (constraints()->check_or_update(k, class_loader, name) == false) {
2183 linkage_error1 = "loader constraint violation: loader (instance of ";
2184 linkage_error2 = ") previously initiated loading for a different type with name \"";
2185 }
2186 }
2187 }
2188
2189 // Throw error now if needed (cannot throw while holding
2190 // SystemDictionary_lock because of rank ordering)
2191
2192 if (linkage_error1) {
2193 ResourceMark rm(THREAD);
2194 const char* class_loader_name = loader_name(class_loader());
2195 char* type_name = k->name()->as_C_string();
2196 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2197 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2198 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2199 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2200 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2201 }
2202 }
2203
2204
2205 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2206 // have been called.
2207 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2208 int p_index, unsigned int p_hash,
2209 InstanceKlass* k,
2210 Handle class_loader,
2211 TRAPS) {
2212 // Compile_lock prevents systemDictionary updates during compilations
2213 assert_locked_or_safepoint(Compile_lock);
2214 Symbol* name = k->name();
2215 ClassLoaderData *loader_data = class_loader_data(class_loader);
2216
2217 {
2218 MutexLocker mu1(SystemDictionary_lock, THREAD);
2219
2220 // See whether biased locking is enabled and if so set it for this
2221 // klass.
2222 // Note that this must be done past the last potential blocking
2223 // point / safepoint. We enable biased locking lazily using a
2224 // VM_Operation to iterate the SystemDictionary and installing the
2225 // biasable mark word into each InstanceKlass's prototype header.
2226 // To avoid race conditions where we accidentally miss enabling the
2227 // optimization for one class in the process of being added to the
2228 // dictionary, we must not safepoint after the test of
2229 // BiasedLocking::enabled().
2230 if (UseBiasedLocking && BiasedLocking::enabled()) {
2231 // Set biased locking bit for all loaded classes; it will be
2232 // cleared if revocation occurs too often for this type
2233 // NOTE that we must only do this when the class is initally
2234 // defined, not each time it is referenced from a new class loader
2235 if (k->class_loader() == class_loader()) {
2236 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2237 }
2238 }
2239
2240 // Make a new dictionary entry.
2241 Dictionary* dictionary = loader_data->dictionary();
2242 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2243 if (sd_check == NULL) {
2244 dictionary->add_klass(d_index, d_hash, name, k);
2245 notice_modification();
2246 }
2247 #ifdef ASSERT
2248 sd_check = find_class(d_index, d_hash, name, dictionary);
2249 assert (sd_check != NULL, "should have entry in dictionary");
2250 // Note: there may be a placeholder entry: for circularity testing
2251 // or for parallel defines
2252 #endif
2253 SystemDictionary_lock->notify_all();
2254 }
2255 }
2256
2257
2258 // Try to find a class name using the loader constraints. The
2259 // loader constraints might know about a class that isn't fully loaded
2260 // yet and these will be ignored.
2261 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2262 Symbol* class_name, Handle class_loader, TRAPS) {
2263
2264 // First see if it has been loaded directly.
2265 // Force the protection domain to be null. (This removes protection checks.)
2266 Handle no_protection_domain;
2267 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2268 no_protection_domain, CHECK_NULL);
2269 if (klass != NULL)
2270 return klass;
2271
2272 // Now look to see if it has been loaded elsewhere, and is subject to
2273 // a loader constraint that would require this loader to return the
2274 // klass that is already loaded.
2275 if (FieldType::is_array(class_name)) {
2276 // For array classes, their Klass*s are not kept in the
2277 // constraint table. The element Klass*s are.
2278 FieldArrayInfo fd;
2279 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2280 if (t != T_OBJECT) {
2281 klass = Universe::typeArrayKlassObj(t);
2282 } else {
2283 MutexLocker mu(SystemDictionary_lock, THREAD);
2284 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2285 }
2286 // If element class already loaded, allocate array klass
2287 if (klass != NULL) {
2288 klass = klass->array_klass_or_null(fd.dimension());
2289 }
2290 } else {
2291 MutexLocker mu(SystemDictionary_lock, THREAD);
2292 // Non-array classes are easy: simply check the constraint table.
2293 klass = constraints()->find_constrained_klass(class_name, class_loader);
2294 }
2295
2296 return klass;
2297 }
2298
2299
2300 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2301 Handle class_loader1,
2302 Handle class_loader2,
2303 Thread* THREAD) {
2304 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2305 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2306
2307 Symbol* constraint_name = NULL;
2308 if (!FieldType::is_array(class_name)) {
2309 constraint_name = class_name;
2310 } else {
2311 // For array classes, their Klass*s are not kept in the
2312 // constraint table. The element classes are.
2313 FieldArrayInfo fd;
2314 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2315 // primitive types always pass
2316 if (t != T_OBJECT) {
2317 return true;
2318 } else {
2319 constraint_name = fd.object_key();
2320 }
2321 }
2322
2323 Dictionary* dictionary1 = loader_data1->dictionary();
2324 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2325 int d_index1 = dictionary1->hash_to_index(d_hash1);
2326
2327 Dictionary* dictionary2 = loader_data2->dictionary();
2328 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2329 int d_index2 = dictionary2->hash_to_index(d_hash2);
2330
2331 {
2332 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2333 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2334 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2335 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2336 klass2, class_loader2);
2337 }
2338 }
2339
2340 // Add entry to resolution error table to record the error when the first
2341 // attempt to resolve a reference to a class has failed.
2342 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2343 Symbol* error, Symbol* message) {
2344 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2345 int index = resolution_errors()->hash_to_index(hash);
2346 {
2347 MutexLocker ml(SystemDictionary_lock, Thread::current());
2348 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2349 }
2350 }
2351
2352 // Delete a resolution error for RedefineClasses for a constant pool is going away
2353 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2354 resolution_errors()->delete_entry(pool);
2355 }
2356
2357 // Lookup resolution error table. Returns error if found, otherwise NULL.
2358 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2359 Symbol** message) {
2360 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2361 int index = resolution_errors()->hash_to_index(hash);
2362 {
2363 MutexLocker ml(SystemDictionary_lock, Thread::current());
2364 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2365 if (entry != NULL) {
2366 *message = entry->message();
2367 return entry->error();
2368 } else {
2369 return NULL;
2370 }
2371 }
2372 }
2373
2374
2375 // Signature constraints ensure that callers and callees agree about
2376 // the meaning of type names in their signatures. This routine is the
2377 // intake for constraints. It collects them from several places:
2378 //
2379 // * LinkResolver::resolve_method (if check_access is true) requires
2380 // that the resolving class (the caller) and the defining class of
2381 // the resolved method (the callee) agree on each type in the
2382 // method's signature.
2383 //
2384 // * LinkResolver::resolve_interface_method performs exactly the same
2385 // checks.
2386 //
2387 // * LinkResolver::resolve_field requires that the constant pool
2388 // attempting to link to a field agree with the field's defining
2389 // class about the type of the field signature.
2390 //
2391 // * klassVtable::initialize_vtable requires that, when a class
2392 // overrides a vtable entry allocated by a superclass, that the
2393 // overriding method (i.e., the callee) agree with the superclass
2394 // on each type in the method's signature.
2395 //
2396 // * klassItable::initialize_itable requires that, when a class fills
2397 // in its itables, for each non-abstract method installed in an
2398 // itable, the method (i.e., the callee) agree with the interface
2399 // on each type in the method's signature.
2400 //
2401 // All those methods have a boolean (check_access, checkconstraints)
2402 // which turns off the checks. This is used from specialized contexts
2403 // such as bootstrapping, dumping, and debugging.
2404 //
2405 // No direct constraint is placed between the class and its
2406 // supertypes. Constraints are only placed along linked relations
2407 // between callers and callees. When a method overrides or implements
2408 // an abstract method in a supertype (superclass or interface), the
2409 // constraints are placed as if the supertype were the caller to the
2410 // overriding method. (This works well, since callers to the
2411 // supertype have already established agreement between themselves and
2412 // the supertype.) As a result of all this, a class can disagree with
2413 // its supertype about the meaning of a type name, as long as that
2414 // class neither calls a relevant method of the supertype, nor is
2415 // called (perhaps via an override) from the supertype.
2416 //
2417 //
2418 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2419 //
2420 // Make sure all class components (including arrays) in the given
2421 // signature will be resolved to the same class in both loaders.
2422 // Returns the name of the type that failed a loader constraint check, or
2423 // NULL if no constraint failed. No exception except OOME is thrown.
2424 // Arrays are not added to the loader constraint table, their elements are.
2425 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2426 Handle loader1, Handle loader2,
2427 bool is_method, TRAPS) {
2428 // Nothing to do if loaders are the same.
2429 if (loader1() == loader2()) {
2430 return NULL;
2431 }
2432
2433 SignatureStream sig_strm(signature, is_method);
2434 while (!sig_strm.is_done()) {
2435 if (sig_strm.is_object()) {
2436 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2437 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2438 return sig;
2439 }
2440 }
2441 sig_strm.next();
2442 }
2443 return NULL;
2444 }
2445
2446
2447 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2448 Symbol* signature,
2449 TRAPS) {
2450 methodHandle empty;
2451 assert(MethodHandles::is_signature_polymorphic(iid) &&
2452 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2453 iid != vmIntrinsics::_invokeGeneric,
2454 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2455
2456 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2457 int index = invoke_method_table()->hash_to_index(hash);
2458 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2459 methodHandle m;
2460 if (spe == NULL || spe->method() == NULL) {
2461 spe = NULL;
2462 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2463 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2464 if (!Arguments::is_interpreter_only()) {
2465 // Generate a compiled form of the MH intrinsic.
2466 AdapterHandlerLibrary::create_native_wrapper(m);
2467 // Check if have the compiled code.
2468 if (!m->has_compiled_code()) {
2469 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2470 "Out of space in CodeCache for method handle intrinsic", empty);
2471 }
2472 }
2473 // Now grab the lock. We might have to throw away the new method,
2474 // if a racing thread has managed to install one at the same time.
2475 {
2476 MutexLocker ml(SystemDictionary_lock, THREAD);
2477 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2478 if (spe == NULL)
2479 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2480 if (spe->method() == NULL)
2481 spe->set_method(m());
2482 }
2483 }
2484
2485 assert(spe != NULL && spe->method() != NULL, "");
2486 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2487 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2488 "MH intrinsic invariant");
2489 return spe->method();
2490 }
2491
2492 // Helper for unpacking the return value from linkMethod and linkCallSite.
2493 static methodHandle unpack_method_and_appendix(Handle mname,
2494 Klass* accessing_klass,
2495 objArrayHandle appendix_box,
2496 Handle* appendix_result,
2497 TRAPS) {
2498 methodHandle empty;
2499 if (mname.not_null()) {
2500 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2501 if (m != NULL) {
2502 oop appendix = appendix_box->obj_at(0);
2503 if (TraceMethodHandles) {
2504 #ifndef PRODUCT
2505 ttyLocker ttyl;
2506 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2507 m->print();
2508 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2509 tty->cr();
2510 #endif //PRODUCT
2511 }
2512 (*appendix_result) = Handle(THREAD, appendix);
2513 // the target is stored in the cpCache and if a reference to this
2514 // MethodName is dropped we need a way to make sure the
2515 // class_loader containing this method is kept alive.
2516 // FIXME: the appendix might also preserve this dependency.
2517 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2518 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2519 return methodHandle(THREAD, m);
2520 }
2521 }
2522 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2523 return empty;
2524 }
2525
2526 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2527 Symbol* name,
2528 Symbol* signature,
2529 Klass* accessing_klass,
2530 Handle *appendix_result,
2531 Handle *method_type_result,
2532 TRAPS) {
2533 methodHandle empty;
2534 assert(THREAD->can_call_java() ,"");
2535 Handle method_type =
2536 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2537
2538 int ref_kind = JVM_REF_invokeVirtual;
2539 oop name_oop = StringTable::intern(name, CHECK_(empty));
2540 Handle name_str (THREAD, name_oop);
2541 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2542 assert(appendix_box->obj_at(0) == NULL, "");
2543
2544 // This should not happen. JDK code should take care of that.
2545 if (accessing_klass == NULL || method_type.is_null()) {
2546 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2547 }
2548
2549 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2550 JavaCallArguments args;
2551 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2552 args.push_int(ref_kind);
2553 args.push_oop(Handle(THREAD, klass->java_mirror()));
2554 args.push_oop(name_str);
2555 args.push_oop(method_type);
2556 args.push_oop(appendix_box);
2557 JavaValue result(T_OBJECT);
2558 JavaCalls::call_static(&result,
2559 SystemDictionary::MethodHandleNatives_klass(),
2560 vmSymbols::linkMethod_name(),
2561 vmSymbols::linkMethod_signature(),
2562 &args, CHECK_(empty));
2563 Handle mname(THREAD, (oop) result.get_jobject());
2564 (*method_type_result) = method_type;
2565 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2566 }
2567
2568 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2569 // We must ensure that all class loaders everywhere will reach this class, for any client.
2570 // This is a safe bet for public classes in java.lang, such as Object and String.
2571 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2572 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2573 static bool is_always_visible_class(oop mirror) {
2574 Klass* klass = java_lang_Class::as_Klass(mirror);
2575 if (klass->is_objArray_klass()) {
2576 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2577 }
2578 if (klass->is_typeArray_klass()) {
2579 return true; // primitive array
2580 }
2581 assert(klass->is_instance_klass(), "%s", klass->external_name());
2582 return klass->is_public() &&
2583 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2584 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2585 }
2586
2587 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2588 // signature, as interpreted relative to the given class loader.
2589 // Because of class loader constraints, all method handle usage must be
2590 // consistent with this loader.
2591 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2592 Klass* accessing_klass,
2593 TRAPS) {
2594 Handle empty;
2595 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2596 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2597 int index = invoke_method_table()->hash_to_index(hash);
2598 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2599 if (spe != NULL && spe->method_type() != NULL) {
2600 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2601 return Handle(THREAD, spe->method_type());
2602 } else if (!THREAD->can_call_java()) {
2603 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2604 return Handle(); // do not attempt from within compiler, unless it was cached
2605 }
2606
2607 Handle class_loader, protection_domain;
2608 if (accessing_klass != NULL) {
2609 class_loader = Handle(THREAD, accessing_klass->class_loader());
2610 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2611 }
2612 bool can_be_cached = true;
2613 int npts = ArgumentCount(signature).size();
2614 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2615 int arg = 0;
2616 Handle rt; // the return type from the signature
2617 ResourceMark rm(THREAD);
2618 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2619 oop mirror = NULL;
2620 if (can_be_cached) {
2621 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2622 mirror = ss.as_java_mirror(Handle(), Handle(),
2623 SignatureStream::ReturnNull, CHECK_(empty));
2624 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2625 // Fall back to accessing_klass context.
2626 can_be_cached = false;
2627 }
2628 }
2629 if (!can_be_cached) {
2630 // Resolve, throwing a real error if it doesn't work.
2631 mirror = ss.as_java_mirror(class_loader, protection_domain,
2632 SignatureStream::NCDFError, CHECK_(empty));
2633 }
2634 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2635 if (ss.at_return_type())
2636 rt = Handle(THREAD, mirror);
2637 else
2638 pts->obj_at_put(arg++, mirror);
2639
2640 // Check accessibility.
2641 if (ss.is_object() && accessing_klass != NULL) {
2642 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2643 mirror = NULL; // safety
2644 // Emulate ConstantPool::verify_constant_pool_resolve.
2645 if (sel_klass->is_objArray_klass())
2646 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2647 if (sel_klass->is_instance_klass()) {
2648 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2649 }
2650 }
2651 }
2652 assert(arg == npts, "");
2653
2654 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2655 JavaCallArguments args(Handle(THREAD, rt()));
2656 args.push_oop(pts);
2657 JavaValue result(T_OBJECT);
2658 JavaCalls::call_static(&result,
2659 SystemDictionary::MethodHandleNatives_klass(),
2660 vmSymbols::findMethodHandleType_name(),
2661 vmSymbols::findMethodHandleType_signature(),
2662 &args, CHECK_(empty));
2663 Handle method_type(THREAD, (oop) result.get_jobject());
2664
2665 if (can_be_cached) {
2666 // We can cache this MethodType inside the JVM.
2667 MutexLocker ml(SystemDictionary_lock, THREAD);
2668 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2669 if (spe == NULL)
2670 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2671 if (spe->method_type() == NULL) {
2672 spe->set_method_type(method_type());
2673 }
2674 }
2675
2676 // report back to the caller with the MethodType
2677 return method_type;
2678 }
2679
2680 // Ask Java code to find or construct a method handle constant.
2681 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2682 int ref_kind, //e.g., JVM_REF_invokeVirtual
2683 Klass* callee,
2684 Symbol* name_sym,
2685 Symbol* signature,
2686 TRAPS) {
2687 Handle empty;
2688 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2689 Handle type;
2690 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2691 type = find_method_handle_type(signature, caller, CHECK_(empty));
2692 } else if (caller == NULL) {
2693 // This should not happen. JDK code should take care of that.
2694 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2695 } else {
2696 ResourceMark rm(THREAD);
2697 SignatureStream ss(signature, false);
2698 if (!ss.is_done()) {
2699 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2700 Handle(THREAD, caller->protection_domain()),
2701 SignatureStream::NCDFError, CHECK_(empty));
2702 type = Handle(THREAD, mirror);
2703 ss.next();
2704 if (!ss.is_done()) type = Handle(); // error!
2705 }
2706 }
2707 if (type.is_null()) {
2708 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2709 }
2710
2711 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2712 JavaCallArguments args;
2713 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2714 args.push_int(ref_kind);
2715 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2716 args.push_oop(name);
2717 args.push_oop(type);
2718 JavaValue result(T_OBJECT);
2719 JavaCalls::call_static(&result,
2720 SystemDictionary::MethodHandleNatives_klass(),
2721 vmSymbols::linkMethodHandleConstant_name(),
2722 vmSymbols::linkMethodHandleConstant_signature(),
2723 &args, CHECK_(empty));
2724 return Handle(THREAD, (oop) result.get_jobject());
2725 }
2726
2727 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2728 // name and signature, as interpreted relative to the given class loader.
2729 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2730 Handle bootstrap_specifier,
2731 Symbol* name,
2732 Symbol* type,
2733 Handle *appendix_result,
2734 Handle *method_type_result,
2735 TRAPS) {
2736 methodHandle empty;
2737 Handle bsm, info;
2738 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2739 bsm = bootstrap_specifier;
2740 } else {
2741 assert(bootstrap_specifier->is_objArray(), "");
2742 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2743 int len = args->length();
2744 assert(len >= 1, "");
2745 bsm = Handle(THREAD, args->obj_at(0));
2746 if (len > 1) {
2747 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2748 for (int i = 1; i < len; i++)
2749 args1->obj_at_put(i-1, args->obj_at(i));
2750 info = Handle(THREAD, args1);
2751 }
2752 }
2753 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2754 "caller must supply a valid BSM");
2755
2756 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2757 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2758
2759 // This should not happen. JDK code should take care of that.
2760 if (caller == NULL || method_type.is_null()) {
2761 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2762 }
2763
2764 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2765 assert(appendix_box->obj_at(0) == NULL, "");
2766
2767 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2768 JavaCallArguments args;
2769 args.push_oop(Handle(THREAD, caller->java_mirror()));
2770 args.push_oop(bsm);
2771 args.push_oop(method_name);
2772 args.push_oop(method_type);
2773 args.push_oop(info);
2774 args.push_oop(appendix_box);
2775 JavaValue result(T_OBJECT);
2776 JavaCalls::call_static(&result,
2777 SystemDictionary::MethodHandleNatives_klass(),
2778 vmSymbols::linkCallSite_name(),
2779 vmSymbols::linkCallSite_signature(),
2780 &args, CHECK_(empty));
2781 Handle mname(THREAD, (oop) result.get_jobject());
2782 (*method_type_result) = method_type;
2783 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2784 }
2785
2786 // Protection domain cache table handling
2787
2788 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2789 return _pd_cache_table->get(protection_domain);
2790 }
2791
2792
2793 void SystemDictionary::reorder_dictionary() {
2794 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary();
2795 }
2796
2797
2798 void SystemDictionary::copy_buckets(char** top, char* end) {
2799 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2800 }
2801
2802
2803 void SystemDictionary::copy_table(char** top, char* end) {
2804 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2805 }
2806
2807 // ----------------------------------------------------------------------------
2808 void SystemDictionary::print_shared(bool details) {
2809 shared_dictionary()->print(details);
2810 }
2811
2812 void SystemDictionary::print(bool details) {
2813 if (shared_dictionary() != NULL) {
2814 tty->print_cr("Shared Dictionary");
2815 shared_dictionary()->print(details);
2816 }
2817
2818 GCMutexLocker mu(SystemDictionary_lock);
2819
2820 ClassLoaderDataGraph::print_dictionary(details);
2821
2822 // Placeholders
2823 placeholders()->print();
2824 tty->cr();
2825
2826 // loader constraints - print under SD_lock
2827 constraints()->print();
2828 tty->cr();
2829
2830 _pd_cache_table->print();
2831 tty->cr();
2832 }
2833
2834
2835 void SystemDictionary::verify() {
2836 guarantee(constraints() != NULL,
2837 "Verify of loader constraints failed");
2838 guarantee(placeholders()->number_of_entries() >= 0,
2839 "Verify of placeholders failed");
2840
2841 // Verify dictionary
2842 ClassLoaderDataGraph::verify_dictionary();
2843
2844 GCMutexLocker mu(SystemDictionary_lock);
2845 placeholders()->verify();
2846
2847 // Verify constraint table
2848 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2849 constraints()->verify(placeholders());
2850
2851 _pd_cache_table->verify();
2852 }
2853
2854 // caller needs ResourceMark
2855 const char* SystemDictionary::loader_name(const oop loader) {
2856 return ((loader) == NULL ? "<bootloader>" :
2857 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2858 }
2859
2860 // caller needs ResourceMark
2861 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2862 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2863 SystemDictionary::loader_name(loader_data->class_loader()));
2864 }