1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/method.inline.hpp"
60 #include "oops/methodData.hpp"
61 #include "oops/objArrayKlass.hpp"
62 #include "oops/objArrayOop.inline.hpp"
63 #include "oops/oop.inline.hpp"
64 #include "oops/symbol.hpp"
65 #include "oops/typeArrayKlass.hpp"
66 #include "prims/jvmtiEnvBase.hpp"
67 #include "prims/resolvedMethodTable.hpp"
68 #include "prims/methodHandles.hpp"
69 #include "runtime/arguments.hpp"
70 #include "runtime/arguments_ext.hpp"
71 #include "runtime/biasedLocking.hpp"
72 #include "runtime/fieldType.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/java.hpp"
75 #include "runtime/javaCalls.hpp"
76 #include "runtime/mutexLocker.hpp"
77 #include "runtime/orderAccess.inline.hpp"
78 #include "runtime/signature.hpp"
79 #include "services/classLoadingService.hpp"
80 #include "services/diagnosticCommand.hpp"
81 #include "services/threadService.hpp"
82 #include "trace/tracing.hpp"
83 #include "utilities/macros.hpp"
84 #if INCLUDE_CDS
85 #include "classfile/sharedClassUtil.hpp"
86 #include "classfile/systemDictionaryShared.hpp"
87 #endif
88 #if INCLUDE_JVMCI
89 #include "jvmci/jvmciRuntime.hpp"
90 #endif
91
92 PlaceholderTable* SystemDictionary::_placeholders = NULL;
93 Dictionary* SystemDictionary::_shared_dictionary = NULL;
94 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
95 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
96 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
97 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
98
99 int SystemDictionary::_number_of_modifications = 0;
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108 oop SystemDictionary::_java_platform_loader = NULL;
109
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149
150 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
151 }
152
153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
155 return ClassLoaderDataGraph::find_or_create(class_loader);
156 }
157
158 // ----------------------------------------------------------------------------
159 // Parallel class loading check
160
161 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
162 if (class_loader.is_null()) return true;
163 if (AlwaysLockClassLoader) return false;
164 return java_lang_ClassLoader::parallelCapable(class_loader());
165 }
166 // ----------------------------------------------------------------------------
167 // ParallelDefineClass flag does not apply to bootclass loader
168 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
169 if (class_loader.is_null()) return false;
170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
171 return true;
172 }
173 return false;
174 }
175
176 // Returns true if the passed class loader is the builtin application class loader
177 // or a custom system class loader. A customer system class loader can be
178 // specified via -Djava.system.class.loader.
179 bool SystemDictionary::is_system_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
184 class_loader == _java_system_loader);
185 }
186
187 // Returns true if the passed class loader is the platform class loader.
188 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
189 if (class_loader == NULL) {
190 return false;
191 }
192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
193 }
194
195 // ----------------------------------------------------------------------------
196 // Resolving of classes
197
198 // Forwards to resolve_or_null
199
200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
202 if (HAS_PENDING_EXCEPTION || klass == NULL) {
203 // can return a null klass
204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
205 }
206 return klass;
207 }
208
209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
210 bool throw_error,
211 Klass* klass, TRAPS) {
212 if (HAS_PENDING_EXCEPTION) {
213 // If we have a pending exception we forward it to the caller, unless throw_error is true,
214 // in which case we have to check whether the pending exception is a ClassNotFoundException,
215 // and if so convert it to a NoClassDefFoundError
216 // And chain the original ClassNotFoundException
217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
218 ResourceMark rm(THREAD);
219 assert(klass == NULL, "Should not have result with exception pending");
220 Handle e(THREAD, PENDING_EXCEPTION);
221 CLEAR_PENDING_EXCEPTION;
222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
223 } else {
224 return NULL;
225 }
226 }
227 // Class not found, throw appropriate error or exception depending on value of throw_error
228 if (klass == NULL) {
229 ResourceMark rm(THREAD);
230 if (throw_error) {
231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
232 } else {
233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
234 }
235 }
236 return klass;
237 }
238
239
240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
241 bool throw_error, TRAPS)
242 {
243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
244 }
245
246
247 // Forwards to resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 assert(THREAD->can_call_java(),
251 "can not load classes with compiler thread: class=%s, classloader=%s",
252 class_name->as_C_string(),
253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
254 if (FieldType::is_array(class_name)) {
255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 } else if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2, CHECK_NULL);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* class_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for CDS dump time.
348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(SystemDictionary_lock, THREAD);
381 Klass* childk = find_class(d_hash, child_name, dictionary);
382 Klass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if class_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->super()) != NULL) &&
391
392 ((quicksuperk->name() == class_name) &&
393 (quicksuperk->class_loader() == class_loader()))) {
394 return quicksuperk;
395 } else {
396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
398 throw_circularity_error = true;
399 }
400 }
401 if (!throw_circularity_error) {
402 // Be careful not to exit resolve_super
403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
404 }
405 }
406 if (throw_circularity_error) {
407 ResourceMark rm(THREAD);
408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
409 }
410
411 // java.lang.Object should have been found above
412 assert(class_name != NULL, "null super class for resolving");
413 // Resolve the super class or interface, check results on return
414 Klass* superk = SystemDictionary::resolve_or_null(class_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 superk = handle_resolution_exception(class_name, true, superk, THREAD);
433 }
434
435 return superk;
436 }
437
438 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
439 Handle class_loader,
440 Handle protection_domain,
441 TRAPS) {
442 if(!has_checkPackageAccess()) return;
443
444 // Now we have to call back to java to check if the initating class has access
445 JavaValue result(T_VOID);
446 LogTarget(Debug, protectiondomain) lt;
447 if (lt.is_enabled()) {
448 ResourceMark rm;
449 // Print out trace information
450 LogStream ls(lt);
451 ls.print_cr("Checking package access");
452 ls.print("class loader: "); class_loader()->print_value_on(&ls);
453 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
454 ls.print(" loading: "); klass->print_value_on(&ls);
455 ls.cr();
456 }
457
458 // This handle and the class_loader handle passed in keeps this class from
459 // being unloaded through several GC points.
460 // The class_loader handle passed in is the initiating loader.
461 Handle mirror(THREAD, klass->java_mirror());
462
463 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
464 JavaCalls::call_special(&result,
465 class_loader,
466 system_loader,
467 vmSymbols::checkPackageAccess_name(),
468 vmSymbols::class_protectiondomain_signature(),
469 mirror,
470 protection_domain,
471 THREAD);
472
473 if (HAS_PENDING_EXCEPTION) {
474 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
475 } else {
476 log_debug(protectiondomain)("granted");
477 }
478
479 if (HAS_PENDING_EXCEPTION) return;
480
481 // If no exception has been thrown, we have validated the protection domain
482 // Insert the protection domain of the initiating class into the set.
483 {
484 ClassLoaderData* loader_data = class_loader_data(class_loader);
485 Dictionary* dictionary = loader_data->dictionary();
486
487 Symbol* kn = klass->name();
488 unsigned int d_hash = dictionary->compute_hash(kn);
489
490 MutexLocker mu(SystemDictionary_lock, THREAD);
491 int d_index = dictionary->hash_to_index(d_hash);
492 dictionary->add_protection_domain(d_index, d_hash, klass,
493 protection_domain, THREAD);
494 }
495 }
496
497 // We only get here if this thread finds that another thread
498 // has already claimed the placeholder token for the current operation,
499 // but that other thread either never owned or gave up the
500 // object lock
501 // Waits on SystemDictionary_lock to indicate placeholder table updated
502 // On return, caller must recheck placeholder table state
503 //
504 // We only get here if
505 // 1) custom classLoader, i.e. not bootstrap classloader
506 // 2) custom classLoader has broken the class loader objectLock
507 // so another thread got here in parallel
508 //
509 // lockObject must be held.
510 // Complicated dance due to lock ordering:
511 // Must first release the classloader object lock to
512 // allow initial definer to complete the class definition
513 // and to avoid deadlock
514 // Reclaim classloader lock object with same original recursion count
515 // Must release SystemDictionary_lock after notify, since
516 // class loader lock must be claimed before SystemDictionary_lock
517 // to prevent deadlocks
518 //
519 // The notify allows applications that did an untimed wait() on
520 // the classloader object lock to not hang.
521 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
522 assert_lock_strong(SystemDictionary_lock);
523
524 bool calledholdinglock
525 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
526 assert(calledholdinglock,"must hold lock for notify");
527 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
528 ObjectSynchronizer::notifyall(lockObject, THREAD);
529 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
530 SystemDictionary_lock->wait();
531 SystemDictionary_lock->unlock();
532 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
533 SystemDictionary_lock->lock();
534 }
535
536 // If the class in is in the placeholder table, class loading is in progress
537 // For cases where the application changes threads to load classes, it
538 // is critical to ClassCircularity detection that we try loading
539 // the superclass on the same thread internally, so we do parallel
540 // super class loading here.
541 // This also is critical in cases where the original thread gets stalled
542 // even in non-circularity situations.
543 // Note: must call resolve_super_or_fail even if null super -
544 // to force placeholder entry creation for this class for circularity detection
545 // Caller must check for pending exception
546 // Returns non-null Klass* if other thread has completed load
547 // and we are done,
548 // If return null Klass* and no pending exception, the caller must load the class
549 InstanceKlass* SystemDictionary::handle_parallel_super_load(
550 Symbol* name, Symbol* superclassname, Handle class_loader,
551 Handle protection_domain, Handle lockObject, TRAPS) {
552
553 ClassLoaderData* loader_data = class_loader_data(class_loader);
554 Dictionary* dictionary = loader_data->dictionary();
555 unsigned int d_hash = dictionary->compute_hash(name);
556 unsigned int p_hash = placeholders()->compute_hash(name);
557 int p_index = placeholders()->hash_to_index(p_hash);
558
559 // superk is not used, resolve_super called for circularity check only
560 // This code is reached in two situations. One if this thread
561 // is loading the same class twice (e.g. ClassCircularity, or
562 // java.lang.instrument).
563 // The second is if another thread started the resolve_super first
564 // and has not yet finished.
565 // In both cases the original caller will clean up the placeholder
566 // entry on error.
567 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
568 superclassname,
569 class_loader,
570 protection_domain,
571 true,
572 CHECK_NULL);
573
574 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
575 // Serial class loaders and bootstrap classloader do wait for superclass loads
576 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
577 MutexLocker mu(SystemDictionary_lock, THREAD);
578 // Check if classloading completed while we were loading superclass or waiting
579 return find_class(d_hash, name, dictionary);
580 }
581
582 // must loop to both handle other placeholder updates
583 // and spurious notifications
584 bool super_load_in_progress = true;
585 PlaceholderEntry* placeholder;
586 while (super_load_in_progress) {
587 MutexLocker mu(SystemDictionary_lock, THREAD);
588 // Check if classloading completed while we were loading superclass or waiting
589 InstanceKlass* check = find_class(d_hash, name, dictionary);
590 if (check != NULL) {
591 // Klass is already loaded, so just return it
592 return check;
593 } else {
594 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
595 if (placeholder && placeholder->super_load_in_progress() ){
596 // We only get here if the application has released the
597 // classloader lock when another thread was in the middle of loading a
598 // superclass/superinterface for this class, and now
599 // this thread is also trying to load this class.
600 // To minimize surprises, the first thread that started to
601 // load a class should be the one to complete the loading
602 // with the classfile it initially expected.
603 // This logic has the current thread wait once it has done
604 // all the superclass/superinterface loading it can, until
605 // the original thread completes the class loading or fails
606 // If it completes we will use the resulting InstanceKlass
607 // which we will find below in the systemDictionary.
608 // We also get here for parallel bootstrap classloader
609 if (class_loader.is_null()) {
610 SystemDictionary_lock->wait();
611 } else {
612 double_lock_wait(lockObject, THREAD);
613 }
614 } else {
615 // If not in SD and not in PH, other thread's load must have failed
616 super_load_in_progress = false;
617 }
618 }
619 }
620 return NULL;
621 }
622
623 static void post_class_load_event(EventClassLoad* event,
624 const InstanceKlass* k,
625 const ClassLoaderData* init_cld) {
626 #if INCLUDE_TRACE
627 assert(event != NULL, "invariant");
628 assert(k != NULL, "invariant");
629 if (event->should_commit()) {
630 event->set_loadedClass(k);
631 event->set_definingClassLoader(k->class_loader_data());
632 event->set_initiatingClassLoader(init_cld);
633 event->commit();
634 }
635 #endif // INCLUDE_TRACE
636 }
637
638 static void class_define_event(InstanceKlass* k,
639 const ClassLoaderData* def_cld) {
640 #if INCLUDE_TRACE
641 EventClassDefine event;
642 if (event.should_commit()) {
643 event.set_definedClass(k);
644 event.set_definingClassLoader(def_cld);
645 event.commit();
646 }
647 #endif // INCLUDE_TRACE
648 }
649
650 // Be careful when modifying this code: once you have run
651 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
652 // you need to find_and_remove it before returning.
653 // So be careful to not exit with a CHECK_ macro betweeen these calls.
654 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
655 Handle class_loader,
656 Handle protection_domain,
657 TRAPS) {
658 assert(name != NULL && !FieldType::is_array(name) &&
659 !FieldType::is_obj(name), "invalid class name");
660
661 EventClassLoad class_load_start_event;
662
663 HandleMark hm(THREAD);
664
665 // Fix for 4474172; see evaluation for more details
666 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
667 ClassLoaderData* loader_data = register_loader(class_loader);
668 Dictionary* dictionary = loader_data->dictionary();
669 unsigned int d_hash = dictionary->compute_hash(name);
670
671 // Do lookup to see if class already exist and the protection domain
672 // has the right access
673 // This call uses find which checks protection domain already matches
674 // All subsequent calls use find_class, and set has_loaded_class so that
675 // before we return a result we call out to java to check for valid protection domain
676 // to allow returning the Klass* and add it to the pd_set if it is valid
677 {
678 Klass* probe = dictionary->find(d_hash, name, protection_domain);
679 if (probe != NULL) return probe;
680 }
681
682 // Non-bootstrap class loaders will call out to class loader and
683 // define via jvm/jni_DefineClass which will acquire the
684 // class loader object lock to protect against multiple threads
685 // defining the class in parallel by accident.
686 // This lock must be acquired here so the waiter will find
687 // any successful result in the SystemDictionary and not attempt
688 // the define.
689 // ParallelCapable Classloaders and the bootstrap classloader
690 // do not acquire lock here.
691 bool DoObjectLock = true;
692 if (is_parallelCapable(class_loader)) {
693 DoObjectLock = false;
694 }
695
696 unsigned int p_hash = placeholders()->compute_hash(name);
697 int p_index = placeholders()->hash_to_index(p_hash);
698
699 // Class is not in SystemDictionary so we have to do loading.
700 // Make sure we are synchronized on the class loader before we proceed
701 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
702 check_loader_lock_contention(lockObject, THREAD);
703 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
704
705 // Check again (after locking) if class already exist in SystemDictionary
706 bool class_has_been_loaded = false;
707 bool super_load_in_progress = false;
708 bool havesupername = false;
709 InstanceKlass* k = NULL;
710 PlaceholderEntry* placeholder;
711 Symbol* superclassname = NULL;
712
713 {
714 MutexLocker mu(SystemDictionary_lock, THREAD);
715 InstanceKlass* check = find_class(d_hash, name, dictionary);
716 if (check != NULL) {
717 // Klass is already loaded, so just return it
718 class_has_been_loaded = true;
719 k = check;
720 } else {
721 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
722 if (placeholder && placeholder->super_load_in_progress()) {
723 super_load_in_progress = true;
724 if (placeholder->havesupername() == true) {
725 superclassname = placeholder->supername();
726 havesupername = true;
727 }
728 }
729 }
730 }
731
732 // If the class is in the placeholder table, class loading is in progress
733 if (super_load_in_progress && havesupername==true) {
734 k = handle_parallel_super_load(name,
735 superclassname,
736 class_loader,
737 protection_domain,
738 lockObject, THREAD);
739 if (HAS_PENDING_EXCEPTION) {
740 return NULL;
741 }
742 if (k != NULL) {
743 class_has_been_loaded = true;
744 }
745 }
746
747 bool throw_circularity_error = false;
748 if (!class_has_been_loaded) {
749 bool load_instance_added = false;
750
751 // add placeholder entry to record loading instance class
752 // Five cases:
753 // All cases need to prevent modifying bootclasssearchpath
754 // in parallel with a classload of same classname
755 // Redefineclasses uses existence of the placeholder for the duration
756 // of the class load to prevent concurrent redefinition of not completely
757 // defined classes.
758 // case 1. traditional classloaders that rely on the classloader object lock
759 // - no other need for LOAD_INSTANCE
760 // case 2. traditional classloaders that break the classloader object lock
761 // as a deadlock workaround. Detection of this case requires that
762 // this check is done while holding the classloader object lock,
763 // and that lock is still held when calling classloader's loadClass.
764 // For these classloaders, we ensure that the first requestor
765 // completes the load and other requestors wait for completion.
766 // case 3. Bootstrap classloader - don't own objectLocker
767 // This classloader supports parallelism at the classloader level,
768 // but only allows a single load of a class/classloader pair.
769 // No performance benefit and no deadlock issues.
770 // case 4. parallelCapable user level classloaders - without objectLocker
771 // Allow parallel classloading of a class/classloader pair
772
773 {
774 MutexLocker mu(SystemDictionary_lock, THREAD);
775 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
776 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
777 if (oldprobe) {
778 // only need check_seen_thread once, not on each loop
779 // 6341374 java/lang/Instrument with -Xcomp
780 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
781 throw_circularity_error = true;
782 } else {
783 // case 1: traditional: should never see load_in_progress.
784 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
785
786 // case 3: bootstrap classloader: prevent futile classloading,
787 // wait on first requestor
788 if (class_loader.is_null()) {
789 SystemDictionary_lock->wait();
790 } else {
791 // case 2: traditional with broken classloader lock. wait on first
792 // requestor.
793 double_lock_wait(lockObject, THREAD);
794 }
795 // Check if classloading completed while we were waiting
796 InstanceKlass* check = find_class(d_hash, name, dictionary);
797 if (check != NULL) {
798 // Klass is already loaded, so just return it
799 k = check;
800 class_has_been_loaded = true;
801 }
802 // check if other thread failed to load and cleaned up
803 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
804 }
805 }
806 }
807 }
808 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
809 // case 4: parallelCapable: allow competing threads to try
810 // LOAD_INSTANCE in parallel
811
812 if (!throw_circularity_error && !class_has_been_loaded) {
813 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
814 load_instance_added = true;
815 // For class loaders that do not acquire the classloader object lock,
816 // if they did not catch another thread holding LOAD_INSTANCE,
817 // need a check analogous to the acquire ObjectLocker/find_class
818 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
819 // one final check if the load has already completed
820 // class loaders holding the ObjectLock shouldn't find the class here
821 InstanceKlass* check = find_class(d_hash, name, dictionary);
822 if (check != NULL) {
823 // Klass is already loaded, so return it after checking/adding protection domain
824 k = check;
825 class_has_been_loaded = true;
826 }
827 }
828 }
829
830 // must throw error outside of owning lock
831 if (throw_circularity_error) {
832 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
833 ResourceMark rm(THREAD);
834 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
835 }
836
837 if (!class_has_been_loaded) {
838
839 // Do actual loading
840 k = load_instance_class(name, class_loader, THREAD);
841
842 // If everything was OK (no exceptions, no null return value), and
843 // class_loader is NOT the defining loader, do a little more bookkeeping.
844 if (!HAS_PENDING_EXCEPTION && k != NULL &&
845 k->class_loader() != class_loader()) {
846
847 check_constraints(d_hash, k, class_loader, false, THREAD);
848
849 // Need to check for a PENDING_EXCEPTION again; check_constraints
850 // can throw and doesn't use the CHECK macro.
851 if (!HAS_PENDING_EXCEPTION) {
852 { // Grabbing the Compile_lock prevents systemDictionary updates
853 // during compilations.
854 MutexLocker mu(Compile_lock, THREAD);
855 update_dictionary(d_hash, p_index, p_hash,
856 k, class_loader, THREAD);
857 }
858
859 if (JvmtiExport::should_post_class_load()) {
860 Thread *thread = THREAD;
861 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
862 JvmtiExport::post_class_load((JavaThread *) thread, k);
863 }
864 }
865 }
866 } // load_instance_class
867
868 if (load_instance_added == true) {
869 // clean up placeholder entries for LOAD_INSTANCE success or error
870 // This brackets the SystemDictionary updates for both defining
871 // and initiating loaders
872 MutexLocker mu(SystemDictionary_lock, THREAD);
873 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
874 SystemDictionary_lock->notify_all();
875 }
876 }
877
878 if (HAS_PENDING_EXCEPTION || k == NULL) {
879 return NULL;
880 }
881
882 post_class_load_event(&class_load_start_event, k, loader_data);
883
884 #ifdef ASSERT
885 {
886 ClassLoaderData* loader_data = k->class_loader_data();
887 MutexLocker mu(SystemDictionary_lock, THREAD);
888 Klass* kk = find_class(name, loader_data);
889 assert(kk == k, "should be present in dictionary");
890 }
891 #endif
892
893 // return if the protection domain in NULL
894 if (protection_domain() == NULL) return k;
895
896 // Check the protection domain has the right access
897 if (dictionary->is_valid_protection_domain(d_hash, name,
898 protection_domain)) {
899 return k;
900 }
901
902 // Verify protection domain. If it fails an exception is thrown
903 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
904
905 return k;
906 }
907
908
909 // This routine does not lock the system dictionary.
910 //
911 // Since readers don't hold a lock, we must make sure that system
912 // dictionary entries are only removed at a safepoint (when only one
913 // thread is running), and are added to in a safe way (all links must
914 // be updated in an MT-safe manner).
915 //
916 // Callers should be aware that an entry could be added just after
917 // _dictionary->bucket(index) is read here, so the caller will not see
918 // the new entry.
919
920 Klass* SystemDictionary::find(Symbol* class_name,
921 Handle class_loader,
922 Handle protection_domain,
923 TRAPS) {
924
925 // The result of this call should be consistent with the result
926 // of the call to resolve_instance_class_or_null().
927 // See evaluation 6790209 and 4474172 for more details.
928 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
929 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
930
931 if (loader_data == NULL) {
932 // If the ClassLoaderData has not been setup,
933 // then the class loader has no entries in the dictionary.
934 return NULL;
935 }
936
937 Dictionary* dictionary = loader_data->dictionary();
938 unsigned int d_hash = dictionary->compute_hash(class_name);
939 return dictionary->find(d_hash, class_name,
940 protection_domain);
941 }
942
943
944 // Look for a loaded instance or array klass by name. Do not do any loading.
945 // return NULL in case of error.
946 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
947 Handle class_loader,
948 Handle protection_domain,
949 TRAPS) {
950 Klass* k = NULL;
951 assert(class_name != NULL, "class name must be non NULL");
952
953 if (FieldType::is_array(class_name)) {
954 // The name refers to an array. Parse the name.
955 // dimension and object_key in FieldArrayInfo are assigned as a
956 // side-effect of this call
957 FieldArrayInfo fd;
958 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
959 if (t != T_OBJECT) {
960 k = Universe::typeArrayKlassObj(t);
961 } else {
962 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
963 }
964 if (k != NULL) {
965 k = k->array_klass_or_null(fd.dimension());
966 }
967 } else {
968 k = find(class_name, class_loader, protection_domain, THREAD);
969 }
970 return k;
971 }
972
973 // Note: this method is much like resolve_from_stream, but
974 // does not publish the classes via the SystemDictionary.
975 // Handles unsafe_DefineAnonymousClass and redefineclasses
976 // RedefinedClasses do not add to the class hierarchy
977 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
978 Handle class_loader,
979 Handle protection_domain,
980 ClassFileStream* st,
981 const InstanceKlass* host_klass,
982 GrowableArray<Handle>* cp_patches,
983 TRAPS) {
984
985 EventClassLoad class_load_start_event;
986
987 ClassLoaderData* loader_data;
988 if (host_klass != NULL) {
989 // Create a new CLD for anonymous class, that uses the same class loader
990 // as the host_klass
991 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
992 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
993 } else {
994 loader_data = ClassLoaderData::class_loader_data(class_loader());
995 }
996
997 assert(st != NULL, "invariant");
998 assert(st->need_verify(), "invariant");
999
1000 // Parse stream and create a klass.
1001 // Note that we do this even though this klass might
1002 // already be present in the SystemDictionary, otherwise we would not
1003 // throw potential ClassFormatErrors.
1004
1005 InstanceKlass* k = KlassFactory::create_from_stream(st,
1006 class_name,
1007 loader_data,
1008 protection_domain,
1009 host_klass,
1010 cp_patches,
1011 CHECK_NULL);
1012
1013 if (host_klass != NULL && k != NULL) {
1014 // If it's anonymous, initialize it now, since nobody else will.
1015
1016 {
1017 MutexLocker mu_r(Compile_lock, THREAD);
1018
1019 // Add to class hierarchy, initialize vtables, and do possible
1020 // deoptimizations.
1021 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1022
1023 // But, do not add to dictionary.
1024
1025 // compiled code dependencies need to be validated anyway
1026 notice_modification();
1027 }
1028
1029 // Rewrite and patch constant pool here.
1030 k->link_class(CHECK_NULL);
1031 if (cp_patches != NULL) {
1032 k->constants()->patch_resolved_references(cp_patches);
1033 }
1034 k->eager_initialize(CHECK_NULL);
1035
1036 // notify jvmti
1037 if (JvmtiExport::should_post_class_load()) {
1038 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1039 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1040 }
1041
1042 post_class_load_event(&class_load_start_event, k, loader_data);
1043 }
1044 assert(host_klass != NULL || NULL == cp_patches,
1045 "cp_patches only found with host_klass");
1046
1047 return k;
1048 }
1049
1050 // Add a klass to the system from a stream (called by jni_DefineClass and
1051 // JVM_DefineClass).
1052 // Note: class_name can be NULL. In that case we do not know the name of
1053 // the class until we have parsed the stream.
1054
1055 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1056 Handle class_loader,
1057 Handle protection_domain,
1058 ClassFileStream* st,
1059 TRAPS) {
1060
1061 HandleMark hm(THREAD);
1062
1063 // Classloaders that support parallelism, e.g. bootstrap classloader,
1064 // do not acquire lock here
1065 bool DoObjectLock = true;
1066 if (is_parallelCapable(class_loader)) {
1067 DoObjectLock = false;
1068 }
1069
1070 ClassLoaderData* loader_data = register_loader(class_loader);
1071
1072 // Make sure we are synchronized on the class loader before we proceed
1073 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1074 check_loader_lock_contention(lockObject, THREAD);
1075 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1076
1077 assert(st != NULL, "invariant");
1078
1079 // Parse the stream and create a klass.
1080 // Note that we do this even though this klass might
1081 // already be present in the SystemDictionary, otherwise we would not
1082 // throw potential ClassFormatErrors.
1083 InstanceKlass* k = NULL;
1084
1085 #if INCLUDE_CDS
1086 if (!DumpSharedSpaces) {
1087 k = SystemDictionaryShared::lookup_from_stream(class_name,
1088 class_loader,
1089 protection_domain,
1090 st,
1091 CHECK_NULL);
1092 }
1093 #endif
1094
1095 if (k == NULL) {
1096 if (st->buffer() == NULL) {
1097 return NULL;
1098 }
1099 k = KlassFactory::create_from_stream(st,
1100 class_name,
1101 loader_data,
1102 protection_domain,
1103 NULL, // host_klass
1104 NULL, // cp_patches
1105 CHECK_NULL);
1106 }
1107
1108 assert(k != NULL, "no klass created");
1109 Symbol* h_name = k->name();
1110 assert(class_name == NULL || class_name == h_name, "name mismatch");
1111
1112 // Add class just loaded
1113 // If a class loader supports parallel classloading handle parallel define requests
1114 // find_or_define_instance_class may return a different InstanceKlass
1115 if (is_parallelCapable(class_loader)) {
1116 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1117 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1118 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1119 assert(defined_k != NULL, "Should have a klass if there's no exception");
1120 loader_data->add_to_deallocate_list(k);
1121 k = defined_k;
1122 }
1123 } else {
1124 define_instance_class(k, THREAD);
1125 }
1126
1127 // If defining the class throws an exception register 'k' for cleanup.
1128 if (HAS_PENDING_EXCEPTION) {
1129 assert(k != NULL, "Must have an instance klass here!");
1130 loader_data->add_to_deallocate_list(k);
1131 return NULL;
1132 }
1133
1134 // Make sure we have an entry in the SystemDictionary on success
1135 debug_only( {
1136 MutexLocker mu(SystemDictionary_lock, THREAD);
1137
1138 Klass* check = find_class(h_name, k->class_loader_data());
1139 assert(check == k, "should be present in the dictionary");
1140 } );
1141
1142 return k;
1143 }
1144
1145 #if INCLUDE_CDS
1146 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1147 int number_of_entries) {
1148 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1149 "bad shared dictionary size.");
1150 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1151 _shared_dictionary_size, t, number_of_entries);
1152 }
1153
1154
1155 // If there is a shared dictionary, then find the entry for the
1156 // given shared system class, if any.
1157
1158 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1159 if (shared_dictionary() != NULL) {
1160 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1161 int d_index = shared_dictionary()->hash_to_index(d_hash);
1162
1163 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1164 } else {
1165 return NULL;
1166 }
1167 }
1168
1169
1170 // Load a class from the shared spaces (found through the shared system
1171 // dictionary). Force the superclass and all interfaces to be loaded.
1172 // Update the class definition to include sibling classes and no
1173 // subclasses (yet). [Classes in the shared space are not part of the
1174 // object hierarchy until loaded.]
1175
1176 InstanceKlass* SystemDictionary::load_shared_class(
1177 Symbol* class_name, Handle class_loader, TRAPS) {
1178 InstanceKlass* ik = find_shared_class(class_name);
1179 // Make sure we only return the boot class for the NULL classloader.
1180 if (ik != NULL &&
1181 ik->is_shared_boot_class() && class_loader.is_null()) {
1182 Handle protection_domain;
1183 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1184 }
1185 return NULL;
1186 }
1187
1188 // Check if a shared class can be loaded by the specific classloader:
1189 //
1190 // NULL classloader:
1191 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1192 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1193 // be defined in an unnamed module.
1194 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1195 InstanceKlass* ik,
1196 Handle class_loader, TRAPS) {
1197 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1198 "Cannot use sharing if java.base is patched");
1199 ResourceMark rm;
1200 int path_index = ik->shared_classpath_index();
1201 ClassLoaderData* loader_data = class_loader_data(class_loader);
1202 if (path_index < 0) {
1203 // path_index < 0 indicates that the class is intended for a custom loader
1204 // and should not be loaded by boot/platform/app loaders
1205 if (loader_data->is_builtin_class_loader_data()) {
1206 return false;
1207 } else {
1208 return true;
1209 }
1210 }
1211 SharedClassPathEntry* ent =
1212 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1213 if (!Universe::is_module_initialized()) {
1214 assert(ent != NULL && ent->is_modules_image(),
1215 "Loading non-bootstrap classes before the module system is initialized");
1216 assert(class_loader.is_null(), "sanity");
1217 return true;
1218 }
1219 // Get the pkg_entry from the classloader
1220 TempNewSymbol pkg_name = NULL;
1221 PackageEntry* pkg_entry = NULL;
1222 ModuleEntry* mod_entry = NULL;
1223 const char* pkg_string = NULL;
1224 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1225 if (pkg_name != NULL) {
1226 pkg_string = pkg_name->as_C_string();
1227 if (loader_data != NULL) {
1228 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1229 }
1230 if (pkg_entry != NULL) {
1231 mod_entry = pkg_entry->module();
1232 }
1233 }
1234
1235 // If the archived class is from a module that has been patched at runtime,
1236 // the class cannot be loaded from the archive.
1237 if (mod_entry != NULL && mod_entry->is_patched()) {
1238 return false;
1239 }
1240
1241 if (class_loader.is_null()) {
1242 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1243 // The NULL classloader can load archived class originated from the
1244 // "modules" jimage and the -Xbootclasspath/a. For class from the
1245 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1246 // by the NULL classloader.
1247 if (mod_entry != NULL) {
1248 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1249 // ModuleEntry's location agrees with the archived class' origination.
1250 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1251 return true; // Module class from the "module" jimage
1252 }
1253 }
1254
1255 // If the archived class is not from the "module" jimage, the class can be
1256 // loaded by the NULL classloader if
1257 //
1258 // 1. the class is from the unamed package
1259 // 2. or, the class is not from a module defined in the NULL classloader
1260 // 3. or, the class is from an unamed module
1261 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1262 // the class is from the -Xbootclasspath/a
1263 if (pkg_string == NULL ||
1264 pkg_entry == NULL ||
1265 pkg_entry->in_unnamed_module()) {
1266 assert(mod_entry == NULL ||
1267 mod_entry == loader_data->unnamed_module(),
1268 "the unnamed module is not defined in the classloader");
1269 return true;
1270 }
1271 }
1272 return false;
1273 } else {
1274 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1275 ik, class_loader, pkg_string, pkg_name,
1276 pkg_entry, mod_entry, CHECK_(false));
1277 return res;
1278 }
1279 }
1280
1281 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1282 Handle class_loader,
1283 Handle protection_domain, TRAPS) {
1284
1285 if (ik != NULL) {
1286 Symbol* class_name = ik->name();
1287
1288 bool visible = is_shared_class_visible(
1289 class_name, ik, class_loader, CHECK_NULL);
1290 if (!visible) {
1291 return NULL;
1292 }
1293
1294 // Resolve the superclass and interfaces. They must be the same
1295 // as in dump time, because the layout of <ik> depends on
1296 // the specific layout of ik->super() and ik->local_interfaces().
1297 //
1298 // If unexpected superclass or interfaces are found, we cannot
1299 // load <ik> from the shared archive.
1300
1301 if (ik->super() != NULL) {
1302 Symbol* cn = ik->super()->name();
1303 Klass *s = resolve_super_or_fail(class_name, cn,
1304 class_loader, protection_domain, true, CHECK_NULL);
1305 if (s != ik->super()) {
1306 // The dynamically resolved super class is not the same as the one we used during dump time,
1307 // so we cannot use ik.
1308 return NULL;
1309 } else {
1310 assert(s->is_shared(), "must be");
1311 }
1312 }
1313
1314 Array<Klass*>* interfaces = ik->local_interfaces();
1315 int num_interfaces = interfaces->length();
1316 for (int index = 0; index < num_interfaces; index++) {
1317 Klass* k = interfaces->at(index);
1318 Symbol* name = k->name();
1319 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1320 if (k != i) {
1321 // The dynamically resolved interface class is not the same as the one we used during dump time,
1322 // so we cannot use ik.
1323 return NULL;
1324 } else {
1325 assert(i->is_shared(), "must be");
1326 }
1327 }
1328
1329 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1330 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1331 if (new_ik != NULL) {
1332 // The class is changed by CFLH. Return the new class. The shared class is
1333 // not used.
1334 return new_ik;
1335 }
1336
1337 // Adjust methods to recover missing data. They need addresses for
1338 // interpreter entry points and their default native method address
1339 // must be reset.
1340
1341 // Updating methods must be done under a lock so multiple
1342 // threads don't update these in parallel
1343 //
1344 // Shared classes are all currently loaded by either the bootstrap or
1345 // internal parallel class loaders, so this will never cause a deadlock
1346 // on a custom class loader lock.
1347
1348 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1349 {
1350 HandleMark hm(THREAD);
1351 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1352 check_loader_lock_contention(lockObject, THREAD);
1353 ObjectLocker ol(lockObject, THREAD, true);
1354 // prohibited package check assumes all classes loaded from archive call
1355 // restore_unshareable_info which calls ik->set_package()
1356 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1357 }
1358
1359 ik->print_class_load_logging(loader_data, NULL, NULL);
1360
1361 // For boot loader, ensure that GetSystemPackage knows that a class in this
1362 // package was loaded.
1363 if (class_loader.is_null()) {
1364 int path_index = ik->shared_classpath_index();
1365 ResourceMark rm;
1366 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1367 }
1368
1369 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1370 // Only dump the classes that can be stored into CDS archive
1371 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1372 ResourceMark rm(THREAD);
1373 classlist_file->print_cr("%s", ik->name()->as_C_string());
1374 classlist_file->flush();
1375 }
1376 }
1377
1378 // notify a class loaded from shared object
1379 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1380 }
1381
1382 ik->set_has_passed_fingerprint_check(false);
1383 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1384 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1385 uint64_t cds_fp = ik->get_stored_fingerprint();
1386 if (aot_fp != 0 && aot_fp == cds_fp) {
1387 // This class matches with a class saved in an AOT library
1388 ik->set_has_passed_fingerprint_check(true);
1389 } else {
1390 ResourceMark rm;
1391 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1392 }
1393 }
1394 return ik;
1395 }
1396
1397 void SystemDictionary::clear_invoke_method_table() {
1398 SymbolPropertyEntry* spe = NULL;
1399 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1400 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1401 while (p != NULL) {
1402 spe = p;
1403 p = p->next();
1404 _invoke_method_table->free_entry(spe);
1405 }
1406 }
1407 }
1408 #endif // INCLUDE_CDS
1409
1410 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1411
1412 if (class_loader.is_null()) {
1413 ResourceMark rm;
1414 PackageEntry* pkg_entry = NULL;
1415 bool search_only_bootloader_append = false;
1416 ClassLoaderData *loader_data = class_loader_data(class_loader);
1417
1418 // Find the package in the boot loader's package entry table.
1419 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1420 if (pkg_name != NULL) {
1421 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1422 }
1423
1424 // Prior to attempting to load the class, enforce the boot loader's
1425 // visibility boundaries.
1426 if (!Universe::is_module_initialized()) {
1427 // During bootstrapping, prior to module initialization, any
1428 // class attempting to be loaded must be checked against the
1429 // java.base packages in the boot loader's PackageEntryTable.
1430 // No class outside of java.base is allowed to be loaded during
1431 // this bootstrapping window.
1432 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1433 // Class is either in the unnamed package or in
1434 // a named package within the unnamed module. Either
1435 // case is outside of java.base, do not attempt to
1436 // load the class post java.base definition. If
1437 // java.base has not been defined, let the class load
1438 // and its package will be checked later by
1439 // ModuleEntryTable::verify_javabase_packages.
1440 if (ModuleEntryTable::javabase_defined()) {
1441 return NULL;
1442 }
1443 } else {
1444 // Check that the class' package is defined within java.base.
1445 ModuleEntry* mod_entry = pkg_entry->module();
1446 Symbol* mod_entry_name = mod_entry->name();
1447 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1448 return NULL;
1449 }
1450 }
1451 } else {
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() ||
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 JavaCalls::call_virtual(&result,
1528 class_loader,
1529 spec_klass,
1530 vmSymbols::loadClass_name(),
1531 vmSymbols::string_class_signature(),
1532 string,
1533 CHECK_NULL);
1534
1535 assert(result.get_type() == T_OBJECT, "just checking");
1536 oop obj = (oop) result.get_jobject();
1537
1538 // Primitive classes return null since forName() can not be
1539 // used to obtain any of the Class objects representing primitives or void
1540 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1541 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1542 // For user defined Java class loaders, check that the name returned is
1543 // the same as that requested. This check is done for the bootstrap
1544 // loader when parsing the class file.
1545 if (class_name == k->name()) {
1546 return k;
1547 }
1548 }
1549 // Class is not found or has the wrong name, return NULL
1550 return NULL;
1551 }
1552 }
1553
1554 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1555
1556 HandleMark hm(THREAD);
1557 ClassLoaderData* loader_data = k->class_loader_data();
1558 Handle class_loader_h(THREAD, loader_data->class_loader());
1559
1560 // for bootstrap and other parallel classloaders don't acquire lock,
1561 // use placeholder token
1562 // If a parallelCapable class loader calls define_instance_class instead of
1563 // find_or_define_instance_class to get here, we have a timing
1564 // hole with systemDictionary updates and check_constraints
1565 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1566 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1567 compute_loader_lock_object(class_loader_h, THREAD)),
1568 "define called without lock");
1569 }
1570
1571 // Check class-loading constraints. Throw exception if violation is detected.
1572 // Grabs and releases SystemDictionary_lock
1573 // The check_constraints/find_class call and update_dictionary sequence
1574 // must be "atomic" for a specific class/classloader pair so we never
1575 // define two different instanceKlasses for that class/classloader pair.
1576 // Existing classloaders will call define_instance_class with the
1577 // classloader lock held
1578 // Parallel classloaders will call find_or_define_instance_class
1579 // which will require a token to perform the define class
1580 Symbol* name_h = k->name();
1581 Dictionary* dictionary = loader_data->dictionary();
1582 unsigned int d_hash = dictionary->compute_hash(name_h);
1583 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1584
1585 // Register class just loaded with class loader (placed in Vector)
1586 // Note we do this before updating the dictionary, as this can
1587 // fail with an OutOfMemoryError (if it does, we will *not* put this
1588 // class in the dictionary and will not update the class hierarchy).
1589 // JVMTI FollowReferences needs to find the classes this way.
1590 if (k->class_loader() != NULL) {
1591 methodHandle m(THREAD, Universe::loader_addClass_method());
1592 JavaValue result(T_VOID);
1593 JavaCallArguments args(class_loader_h);
1594 args.push_oop(Handle(THREAD, k->java_mirror()));
1595 JavaCalls::call(&result, m, &args, CHECK);
1596 }
1597
1598 // Add the new class. We need recompile lock during update of CHA.
1599 {
1600 unsigned int p_hash = placeholders()->compute_hash(name_h);
1601 int p_index = placeholders()->hash_to_index(p_hash);
1602
1603 MutexLocker mu_r(Compile_lock, THREAD);
1604
1605 // Add to class hierarchy, initialize vtables, and do possible
1606 // deoptimizations.
1607 add_to_hierarchy(k, CHECK); // No exception, but can block
1608
1609 // Add to systemDictionary - so other classes can see it.
1610 // Grabs and releases SystemDictionary_lock
1611 update_dictionary(d_hash, p_index, p_hash,
1612 k, class_loader_h, THREAD);
1613 }
1614 k->eager_initialize(THREAD);
1615
1616 // notify jvmti
1617 if (JvmtiExport::should_post_class_load()) {
1618 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1619 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1620
1621 }
1622 class_define_event(k, loader_data);
1623 }
1624
1625 // Support parallel classloading
1626 // All parallel class loaders, including bootstrap classloader
1627 // lock a placeholder entry for this class/class_loader pair
1628 // to allow parallel defines of different classes for this class loader
1629 // With AllowParallelDefine flag==true, in case they do not synchronize around
1630 // FindLoadedClass/DefineClass, calls, we check for parallel
1631 // loading for them, wait if a defineClass is in progress
1632 // and return the initial requestor's results
1633 // This flag does not apply to the bootstrap classloader.
1634 // With AllowParallelDefine flag==false, call through to define_instance_class
1635 // which will throw LinkageError: duplicate class definition.
1636 // False is the requested default.
1637 // For better performance, the class loaders should synchronize
1638 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1639 // potentially waste time reading and parsing the bytestream.
1640 // Note: VM callers should ensure consistency of k/class_name,class_loader
1641 // Be careful when modifying this code: once you have run
1642 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1643 // you need to find_and_remove it before returning.
1644 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1645 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1646 InstanceKlass* k, TRAPS) {
1647
1648 Symbol* name_h = k->name(); // passed in class_name may be null
1649 ClassLoaderData* loader_data = class_loader_data(class_loader);
1650 Dictionary* dictionary = loader_data->dictionary();
1651
1652 unsigned int d_hash = dictionary->compute_hash(name_h);
1653
1654 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1655 unsigned int p_hash = placeholders()->compute_hash(name_h);
1656 int p_index = placeholders()->hash_to_index(p_hash);
1657 PlaceholderEntry* probe;
1658
1659 {
1660 MutexLocker mu(SystemDictionary_lock, THREAD);
1661 // First check if class already defined
1662 if (is_parallelDefine(class_loader)) {
1663 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1664 if (check != NULL) {
1665 return check;
1666 }
1667 }
1668
1669 // Acquire define token for this class/classloader
1670 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1671 // Wait if another thread defining in parallel
1672 // All threads wait - even those that will throw duplicate class: otherwise
1673 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1674 // if other thread has not finished updating dictionary
1675 while (probe->definer() != NULL) {
1676 SystemDictionary_lock->wait();
1677 }
1678 // Only special cases allow parallel defines and can use other thread's results
1679 // Other cases fall through, and may run into duplicate defines
1680 // caught by finding an entry in the SystemDictionary
1681 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1682 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1683 SystemDictionary_lock->notify_all();
1684 #ifdef ASSERT
1685 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1686 assert(check != NULL, "definer missed recording success");
1687 #endif
1688 return probe->instance_klass();
1689 } else {
1690 // This thread will define the class (even if earlier thread tried and had an error)
1691 probe->set_definer(THREAD);
1692 }
1693 }
1694
1695 define_instance_class(k, THREAD);
1696
1697 Handle linkage_exception = Handle(); // null handle
1698
1699 // definer must notify any waiting threads
1700 {
1701 MutexLocker mu(SystemDictionary_lock, THREAD);
1702 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1703 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1704 if (probe != NULL) {
1705 if (HAS_PENDING_EXCEPTION) {
1706 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1707 CLEAR_PENDING_EXCEPTION;
1708 } else {
1709 probe->set_instance_klass(k);
1710 }
1711 probe->set_definer(NULL);
1712 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1713 SystemDictionary_lock->notify_all();
1714 }
1715 }
1716
1717 // Can't throw exception while holding lock due to rank ordering
1718 if (linkage_exception() != NULL) {
1719 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1720 }
1721
1722 return k;
1723 }
1724
1725 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1726 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1727 if (class_loader.is_null()) {
1728 return Handle(THREAD, _system_loader_lock_obj);
1729 } else {
1730 return class_loader;
1731 }
1732 }
1733
1734 // This method is added to check how often we have to wait to grab loader
1735 // lock. The results are being recorded in the performance counters defined in
1736 // ClassLoader::_sync_systemLoaderLockContentionRate and
1737 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1738 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1739 if (!UsePerfData) {
1740 return;
1741 }
1742
1743 assert(!loader_lock.is_null(), "NULL lock object");
1744
1745 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1746 == ObjectSynchronizer::owner_other) {
1747 // contention will likely happen, so increment the corresponding
1748 // contention counter.
1749 if (loader_lock() == _system_loader_lock_obj) {
1750 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1751 } else {
1752 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1753 }
1754 }
1755 }
1756
1757 // ----------------------------------------------------------------------------
1758 // Lookup
1759
1760 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1761 Symbol* class_name,
1762 Dictionary* dictionary) {
1763 assert_locked_or_safepoint(SystemDictionary_lock);
1764 int index = dictionary->hash_to_index(hash);
1765 return dictionary->find_class(index, hash, class_name);
1766 }
1767
1768
1769 // Basic find on classes in the midst of being loaded
1770 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1771 ClassLoaderData* loader_data) {
1772 assert_locked_or_safepoint(SystemDictionary_lock);
1773 unsigned int p_hash = placeholders()->compute_hash(class_name);
1774 int p_index = placeholders()->hash_to_index(p_hash);
1775 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1776 }
1777
1778
1779 // Used for assertions and verification only
1780 // Precalculating the hash and index is an optimization because there are many lookups
1781 // before adding the class.
1782 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1783 assert_locked_or_safepoint(SystemDictionary_lock);
1784 #ifndef ASSERT
1785 guarantee(VerifyBeforeGC ||
1786 VerifyDuringGC ||
1787 VerifyBeforeExit ||
1788 VerifyDuringStartup ||
1789 VerifyAfterGC, "too expensive");
1790 #endif
1791
1792 Dictionary* dictionary = loader_data->dictionary();
1793 unsigned int d_hash = dictionary->compute_hash(class_name);
1794 return find_class(d_hash, class_name, dictionary);
1795 }
1796
1797
1798 // ----------------------------------------------------------------------------
1799 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1800 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1801 // before a new class is used.
1802
1803 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1804 assert(k != NULL, "just checking");
1805 assert_locked_or_safepoint(Compile_lock);
1806
1807 // Link into hierachy. Make sure the vtables are initialized before linking into
1808 k->append_to_sibling_list(); // add to superklass/sibling list
1809 k->process_interfaces(THREAD); // handle all "implements" declarations
1810 k->set_init_state(InstanceKlass::loaded);
1811 // Now flush all code that depended on old class hierarchy.
1812 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1813 // Also, first reinitialize vtable because it may have gotten out of synch
1814 // while the new class wasn't connected to the class hierarchy.
1815 CodeCache::flush_dependents_on(k);
1816 }
1817
1818 // ----------------------------------------------------------------------------
1819 // GC support
1820
1821 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1822 roots_oops_do(blk, NULL);
1823 }
1824
1825
1826 #ifdef ASSERT
1827 class VerifySDReachableAndLiveClosure : public OopClosure {
1828 private:
1829 BoolObjectClosure* _is_alive;
1830
1831 template <class T> void do_oop_work(T* p) {
1832 oop obj = oopDesc::load_decode_heap_oop(p);
1833 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1834 }
1835
1836 public:
1837 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1838
1839 virtual void do_oop(oop* p) { do_oop_work(p); }
1840 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1841 };
1842 #endif
1843
1844 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1845 // Note: anonymous classes are not in the SD.
1846 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1847 GCTimer* gc_timer,
1848 bool do_cleaning) {
1849
1850
1851 bool unloading_occurred;
1852 {
1853 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1854
1855 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1856 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1857 do_cleaning);
1858 }
1859
1860 if (unloading_occurred) {
1861 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1862 constraints()->purge_loader_constraints();
1863 resolution_errors()->purge_resolution_errors();
1864 }
1865
1866 {
1867 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1868 // Oops referenced by the protection domain cache table may get unreachable independently
1869 // of the class loader (eg. cached protection domain oops). So we need to
1870 // explicitly unlink them here.
1871 _pd_cache_table->unlink(is_alive);
1872
1873 #ifdef ASSERT
1874 VerifySDReachableAndLiveClosure cl(is_alive);
1875 _pd_cache_table->oops_do(&cl);
1876 #endif
1877 }
1878
1879 if (do_cleaning) {
1880 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1881 ResolvedMethodTable::unlink(is_alive);
1882 }
1883
1884 return unloading_occurred;
1885 }
1886
1887 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1888 strong->do_oop(&_java_system_loader);
1889 strong->do_oop(&_java_platform_loader);
1890 strong->do_oop(&_system_loader_lock_obj);
1891 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1892
1893 // Do strong roots marking if the closures are the same.
1894 if (strong == weak || !ClassUnloading) {
1895 // Only the protection domain oops contain references into the heap. Iterate
1896 // over all of them.
1897 _pd_cache_table->oops_do(strong);
1898 } else {
1899 if (weak != NULL) {
1900 _pd_cache_table->oops_do(weak);
1901 }
1902 }
1903
1904 // Visit extra methods
1905 invoke_method_table()->oops_do(strong);
1906
1907 if (weak != NULL) {
1908 ResolvedMethodTable::oops_do(weak);
1909 }
1910 }
1911
1912 void SystemDictionary::oops_do(OopClosure* f) {
1913 f->do_oop(&_java_system_loader);
1914 f->do_oop(&_java_platform_loader);
1915 f->do_oop(&_system_loader_lock_obj);
1916 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1917
1918 // Only the protection domain oops contain references into the heap. Iterate
1919 // over all of them.
1920 _pd_cache_table->oops_do(f);
1921
1922 // Visit extra methods
1923 invoke_method_table()->oops_do(f);
1924
1925 ResolvedMethodTable::oops_do(f);
1926 }
1927
1928 // CDS: scan and relocate all classes in the system dictionary.
1929 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1930 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1931 }
1932
1933 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1934 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1935 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1936 it->push(well_known_klass_addr((WKID)id));
1937 }
1938 }
1939
1940 void SystemDictionary::methods_do(void f(Method*)) {
1941 // Walk methods in loaded classes
1942 ClassLoaderDataGraph::methods_do(f);
1943 // Walk method handle intrinsics
1944 invoke_method_table()->methods_do(f);
1945 }
1946
1947 class RemoveClassesClosure : public CLDClosure {
1948 public:
1949 void do_cld(ClassLoaderData* cld) {
1950 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1951 cld->dictionary()->remove_classes_in_error_state();
1952 }
1953 }
1954 };
1955
1956 void SystemDictionary::remove_classes_in_error_state() {
1957 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1958 RemoveClassesClosure rcc;
1959 ClassLoaderDataGraph::cld_do(&rcc);
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 checkPackageAccess or NOT
2119 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2120 _has_checkPackageAccess = (method != NULL);
2121 }
2122 }
2123
2124 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2125 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2126 BasicType SystemDictionary::box_klass_type(Klass* k) {
2127 assert(k != NULL, "");
2128 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2129 if (_box_klasses[i] == k)
2130 return (BasicType)i;
2131 }
2132 return T_OBJECT;
2133 }
2134
2135 // Constraints on class loaders. The details of the algorithm can be
2136 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2137 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2138 // that the dictionary needs to maintain a set of contraints that
2139 // must be satisfied by all classes in the dictionary.
2140 // if defining is true, then LinkageError if already in dictionary
2141 // if initiating loader, then ok if InstanceKlass matches existing entry
2142
2143 void SystemDictionary::check_constraints(unsigned int d_hash,
2144 InstanceKlass* k,
2145 Handle class_loader,
2146 bool defining,
2147 TRAPS) {
2148 const char *linkage_error1 = NULL;
2149 const char *linkage_error2 = NULL;
2150 const char *linkage_error3 = "";
2151 // Remember the loader of the similar class that is already loaded.
2152 const char *existing_klass_loader_name = "";
2153
2154 {
2155 Symbol* name = k->name();
2156 ClassLoaderData *loader_data = class_loader_data(class_loader);
2157
2158 MutexLocker mu(SystemDictionary_lock, THREAD);
2159
2160 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2161 if (check != NULL) {
2162 // If different InstanceKlass - duplicate class definition,
2163 // else - ok, class loaded by a different thread in parallel.
2164 // We should only have found it if it was done loading and ok to use.
2165 // The dictionary only holds instance classes, placeholders
2166 // also hold array classes.
2167
2168 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2169 if ((defining == true) || (k != check)) {
2170 linkage_error1 = "loader ";
2171 linkage_error2 = " attempted duplicate class definition for ";
2172 guarantee(check->class_loader() == class_loader(), "Per construction. Else report the other loader.");
2173 } else {
2174 return;
2175 }
2176 }
2177
2178 #ifdef ASSERT
2179 Symbol* ph_check = find_placeholder(name, loader_data);
2180 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2181 #endif
2182
2183 if (linkage_error1 == NULL) {
2184 if (constraints()->check_or_update(k, class_loader, name) == false) {
2185 linkage_error1 = "loader constraint violation: loader ";
2186 linkage_error2 = " wants to load class ";
2187 linkage_error3 = ". A different class with the same name was previously loaded by ";
2188 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2189 if (existing_klass->class_loader() != class_loader()) {
2190 existing_klass_loader_name =
2191 java_lang_ClassLoader::describe_external(existing_klass->class_loader());
2192 }
2193 }
2194 }
2195 }
2196
2197 // Throw error now if needed (cannot throw while holding
2198 // SystemDictionary_lock because of rank ordering)
2199
2200 if (linkage_error1) {
2201 ResourceMark rm(THREAD);
2202 stringStream ss;
2203 ss.print("%s", linkage_error1);
2204 ss.print("%s", java_lang_ClassLoader::describe_external(class_loader()));
2205 ss.print("%s", linkage_error2);
2206 ss.print("%s", k->external_name());
2207 ss.print("%s", linkage_error3);
2208 ss.print("%s", existing_klass_loader_name);
2209 ss.print(".");
2210 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2211 }
2212 }
2213
2214 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2215 // have been called.
2216 void SystemDictionary::update_dictionary(unsigned int d_hash,
2217 int p_index, unsigned int p_hash,
2218 InstanceKlass* k,
2219 Handle class_loader,
2220 TRAPS) {
2221 // Compile_lock prevents systemDictionary updates during compilations
2222 assert_locked_or_safepoint(Compile_lock);
2223 Symbol* name = k->name();
2224 ClassLoaderData *loader_data = class_loader_data(class_loader);
2225
2226 {
2227 MutexLocker mu1(SystemDictionary_lock, THREAD);
2228
2229 // See whether biased locking is enabled and if so set it for this
2230 // klass.
2231 // Note that this must be done past the last potential blocking
2232 // point / safepoint. We enable biased locking lazily using a
2233 // VM_Operation to iterate the SystemDictionary and installing the
2234 // biasable mark word into each InstanceKlass's prototype header.
2235 // To avoid race conditions where we accidentally miss enabling the
2236 // optimization for one class in the process of being added to the
2237 // dictionary, we must not safepoint after the test of
2238 // BiasedLocking::enabled().
2239 if (UseBiasedLocking && BiasedLocking::enabled()) {
2240 // Set biased locking bit for all loaded classes; it will be
2241 // cleared if revocation occurs too often for this type
2242 // NOTE that we must only do this when the class is initally
2243 // defined, not each time it is referenced from a new class loader
2244 if (k->class_loader() == class_loader()) {
2245 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2246 }
2247 }
2248
2249 // Make a new dictionary entry.
2250 Dictionary* dictionary = loader_data->dictionary();
2251 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2252 if (sd_check == NULL) {
2253 dictionary->add_klass(d_hash, name, k);
2254 notice_modification();
2255 }
2256 #ifdef ASSERT
2257 sd_check = find_class(d_hash, name, dictionary);
2258 assert (sd_check != NULL, "should have entry in dictionary");
2259 // Note: there may be a placeholder entry: for circularity testing
2260 // or for parallel defines
2261 #endif
2262 SystemDictionary_lock->notify_all();
2263 }
2264 }
2265
2266
2267 // Try to find a class name using the loader constraints. The
2268 // loader constraints might know about a class that isn't fully loaded
2269 // yet and these will be ignored.
2270 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2271 Symbol* class_name, Handle class_loader, TRAPS) {
2272
2273 // First see if it has been loaded directly.
2274 // Force the protection domain to be null. (This removes protection checks.)
2275 Handle no_protection_domain;
2276 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2277 no_protection_domain, CHECK_NULL);
2278 if (klass != NULL)
2279 return klass;
2280
2281 // Now look to see if it has been loaded elsewhere, and is subject to
2282 // a loader constraint that would require this loader to return the
2283 // klass that is already loaded.
2284 if (FieldType::is_array(class_name)) {
2285 // For array classes, their Klass*s are not kept in the
2286 // constraint table. The element Klass*s are.
2287 FieldArrayInfo fd;
2288 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2289 if (t != T_OBJECT) {
2290 klass = Universe::typeArrayKlassObj(t);
2291 } else {
2292 MutexLocker mu(SystemDictionary_lock, THREAD);
2293 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2294 }
2295 // If element class already loaded, allocate array klass
2296 if (klass != NULL) {
2297 klass = klass->array_klass_or_null(fd.dimension());
2298 }
2299 } else {
2300 MutexLocker mu(SystemDictionary_lock, THREAD);
2301 // Non-array classes are easy: simply check the constraint table.
2302 klass = constraints()->find_constrained_klass(class_name, class_loader);
2303 }
2304
2305 return klass;
2306 }
2307
2308
2309 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2310 Handle class_loader1,
2311 Handle class_loader2,
2312 Thread* THREAD) {
2313 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2314 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2315
2316 Symbol* constraint_name = NULL;
2317 if (!FieldType::is_array(class_name)) {
2318 constraint_name = class_name;
2319 } else {
2320 // For array classes, their Klass*s are not kept in the
2321 // constraint table. The element classes are.
2322 FieldArrayInfo fd;
2323 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2324 // primitive types always pass
2325 if (t != T_OBJECT) {
2326 return true;
2327 } else {
2328 constraint_name = fd.object_key();
2329 }
2330 }
2331
2332 Dictionary* dictionary1 = loader_data1->dictionary();
2333 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2334
2335 Dictionary* dictionary2 = loader_data2->dictionary();
2336 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2337
2338 {
2339 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2340 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2341 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2342 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2343 klass2, class_loader2);
2344 }
2345 }
2346
2347 // Add entry to resolution error table to record the error when the first
2348 // attempt to resolve a reference to a class has failed.
2349 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2350 Symbol* error, Symbol* message) {
2351 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2352 int index = resolution_errors()->hash_to_index(hash);
2353 {
2354 MutexLocker ml(SystemDictionary_lock, Thread::current());
2355 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2356 }
2357 }
2358
2359 // Delete a resolution error for RedefineClasses for a constant pool is going away
2360 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2361 resolution_errors()->delete_entry(pool);
2362 }
2363
2364 // Lookup resolution error table. Returns error if found, otherwise NULL.
2365 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2366 Symbol** message) {
2367 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2368 int index = resolution_errors()->hash_to_index(hash);
2369 {
2370 MutexLocker ml(SystemDictionary_lock, Thread::current());
2371 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2372 if (entry != NULL) {
2373 *message = entry->message();
2374 return entry->error();
2375 } else {
2376 return NULL;
2377 }
2378 }
2379 }
2380
2381
2382 // Signature constraints ensure that callers and callees agree about
2383 // the meaning of type names in their signatures. This routine is the
2384 // intake for constraints. It collects them from several places:
2385 //
2386 // * LinkResolver::resolve_method (if check_access is true) requires
2387 // that the resolving class (the caller) and the defining class of
2388 // the resolved method (the callee) agree on each type in the
2389 // method's signature.
2390 //
2391 // * LinkResolver::resolve_interface_method performs exactly the same
2392 // checks.
2393 //
2394 // * LinkResolver::resolve_field requires that the constant pool
2395 // attempting to link to a field agree with the field's defining
2396 // class about the type of the field signature.
2397 //
2398 // * klassVtable::initialize_vtable requires that, when a class
2399 // overrides a vtable entry allocated by a superclass, that the
2400 // overriding method (i.e., the callee) agree with the superclass
2401 // on each type in the method's signature.
2402 //
2403 // * klassItable::initialize_itable requires that, when a class fills
2404 // in its itables, for each non-abstract method installed in an
2405 // itable, the method (i.e., the callee) agree with the interface
2406 // on each type in the method's signature.
2407 //
2408 // All those methods have a boolean (check_access, checkconstraints)
2409 // which turns off the checks. This is used from specialized contexts
2410 // such as bootstrapping, dumping, and debugging.
2411 //
2412 // No direct constraint is placed between the class and its
2413 // supertypes. Constraints are only placed along linked relations
2414 // between callers and callees. When a method overrides or implements
2415 // an abstract method in a supertype (superclass or interface), the
2416 // constraints are placed as if the supertype were the caller to the
2417 // overriding method. (This works well, since callers to the
2418 // supertype have already established agreement between themselves and
2419 // the supertype.) As a result of all this, a class can disagree with
2420 // its supertype about the meaning of a type name, as long as that
2421 // class neither calls a relevant method of the supertype, nor is
2422 // called (perhaps via an override) from the supertype.
2423 //
2424 //
2425 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2426 //
2427 // Make sure all class components (including arrays) in the given
2428 // signature will be resolved to the same class in both loaders.
2429 // Returns the name of the type that failed a loader constraint check, or
2430 // NULL if no constraint failed. No exception except OOME is thrown.
2431 // Arrays are not added to the loader constraint table, their elements are.
2432 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2433 Handle loader1, Handle loader2,
2434 bool is_method, TRAPS) {
2435 // Nothing to do if loaders are the same.
2436 if (loader1() == loader2()) {
2437 return NULL;
2438 }
2439
2440 SignatureStream sig_strm(signature, is_method);
2441 while (!sig_strm.is_done()) {
2442 if (sig_strm.is_object()) {
2443 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2444 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2445 return sig;
2446 }
2447 }
2448 sig_strm.next();
2449 }
2450 return NULL;
2451 }
2452
2453
2454 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2455 Symbol* signature,
2456 TRAPS) {
2457 methodHandle empty;
2458 assert(MethodHandles::is_signature_polymorphic(iid) &&
2459 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2460 iid != vmIntrinsics::_invokeGeneric,
2461 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2462
2463 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2464 int index = invoke_method_table()->hash_to_index(hash);
2465 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2466 methodHandle m;
2467 if (spe == NULL || spe->method() == NULL) {
2468 spe = NULL;
2469 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2470 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2471 if (!Arguments::is_interpreter_only()) {
2472 // Generate a compiled form of the MH intrinsic.
2473 AdapterHandlerLibrary::create_native_wrapper(m);
2474 // Check if have the compiled code.
2475 if (!m->has_compiled_code()) {
2476 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2477 "Out of space in CodeCache for method handle intrinsic", empty);
2478 }
2479 }
2480 // Now grab the lock. We might have to throw away the new method,
2481 // if a racing thread has managed to install one at the same time.
2482 {
2483 MutexLocker ml(SystemDictionary_lock, THREAD);
2484 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2485 if (spe == NULL)
2486 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2487 if (spe->method() == NULL)
2488 spe->set_method(m());
2489 }
2490 }
2491
2492 assert(spe != NULL && spe->method() != NULL, "");
2493 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2494 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2495 "MH intrinsic invariant");
2496 return spe->method();
2497 }
2498
2499 // Helper for unpacking the return value from linkMethod and linkCallSite.
2500 static methodHandle unpack_method_and_appendix(Handle mname,
2501 Klass* accessing_klass,
2502 objArrayHandle appendix_box,
2503 Handle* appendix_result,
2504 TRAPS) {
2505 methodHandle empty;
2506 if (mname.not_null()) {
2507 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2508 if (m != NULL) {
2509 oop appendix = appendix_box->obj_at(0);
2510 if (TraceMethodHandles) {
2511 #ifndef PRODUCT
2512 ttyLocker ttyl;
2513 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2514 m->print();
2515 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2516 tty->cr();
2517 #endif //PRODUCT
2518 }
2519 (*appendix_result) = Handle(THREAD, appendix);
2520 // the target is stored in the cpCache and if a reference to this
2521 // MemberName is dropped we need a way to make sure the
2522 // class_loader containing this method is kept alive.
2523 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2524 this_key->record_dependency(m->method_holder());
2525 return methodHandle(THREAD, m);
2526 }
2527 }
2528 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2529 return empty;
2530 }
2531
2532 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2533 Symbol* name,
2534 Symbol* signature,
2535 Klass* accessing_klass,
2536 Handle *appendix_result,
2537 Handle *method_type_result,
2538 TRAPS) {
2539 methodHandle empty;
2540 assert(THREAD->can_call_java() ,"");
2541 Handle method_type =
2542 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2543
2544 int ref_kind = JVM_REF_invokeVirtual;
2545 oop name_oop = StringTable::intern(name, CHECK_(empty));
2546 Handle name_str (THREAD, name_oop);
2547 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2548 assert(appendix_box->obj_at(0) == NULL, "");
2549
2550 // This should not happen. JDK code should take care of that.
2551 if (accessing_klass == NULL || method_type.is_null()) {
2552 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2553 }
2554
2555 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2556 JavaCallArguments args;
2557 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2558 args.push_int(ref_kind);
2559 args.push_oop(Handle(THREAD, klass->java_mirror()));
2560 args.push_oop(name_str);
2561 args.push_oop(method_type);
2562 args.push_oop(appendix_box);
2563 JavaValue result(T_OBJECT);
2564 JavaCalls::call_static(&result,
2565 SystemDictionary::MethodHandleNatives_klass(),
2566 vmSymbols::linkMethod_name(),
2567 vmSymbols::linkMethod_signature(),
2568 &args, CHECK_(empty));
2569 Handle mname(THREAD, (oop) result.get_jobject());
2570 (*method_type_result) = method_type;
2571 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2572 }
2573
2574 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2575 // We must ensure that all class loaders everywhere will reach this class, for any client.
2576 // This is a safe bet for public classes in java.lang, such as Object and String.
2577 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2578 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2579 static bool is_always_visible_class(oop mirror) {
2580 Klass* klass = java_lang_Class::as_Klass(mirror);
2581 if (klass->is_objArray_klass()) {
2582 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2583 }
2584 if (klass->is_typeArray_klass()) {
2585 return true; // primitive array
2586 }
2587 assert(klass->is_instance_klass(), "%s", klass->external_name());
2588 return klass->is_public() &&
2589 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2590 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2591 }
2592
2593
2594 // Return the Java mirror (java.lang.Class instance) for a single-character
2595 // descriptor. This result, when available, is the same as produced by the
2596 // heavier API point of the same name that takes a Symbol.
2597 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2598 return java_lang_Class::primitive_mirror(char2type(signature_char));
2599 }
2600
2601 // Find or construct the Java mirror (java.lang.Class instance) for a
2602 // for the given field type signature, as interpreted relative to the
2603 // given class loader. Handles primitives, void, references, arrays,
2604 // and all other reflectable types, except method types.
2605 // N.B. Code in reflection should use this entry point.
2606 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2607 Klass* accessing_klass,
2608 Handle class_loader,
2609 Handle protection_domain,
2610 SignatureStream::FailureMode failure_mode,
2611 TRAPS) {
2612 Handle empty;
2613
2614 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2615 "one or the other, or perhaps neither");
2616
2617 Symbol* type = signature;
2618
2619 // What we have here must be a valid field descriptor,
2620 // and all valid field descriptors are supported.
2621 // Produce the same java.lang.Class that reflection reports.
2622 if (type->utf8_length() == 1) {
2623
2624 // It's a primitive. (Void has a primitive mirror too.)
2625 char ch = (char) type->byte_at(0);
2626 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2627 return Handle(THREAD, find_java_mirror_for_type(ch));
2628
2629 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2630
2631 // It's a reference type.
2632 if (accessing_klass != NULL) {
2633 class_loader = Handle(THREAD, accessing_klass->class_loader());
2634 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2635 }
2636 Klass* constant_type_klass;
2637 if (failure_mode == SignatureStream::ReturnNull) {
2638 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2639 CHECK_(empty));
2640 } else {
2641 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2642 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2643 throw_error, CHECK_(empty));
2644 }
2645 if (constant_type_klass == NULL) {
2646 return Handle(); // report failure this way
2647 }
2648 Handle mirror(THREAD, constant_type_klass->java_mirror());
2649
2650 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2651 if (accessing_klass != NULL) {
2652 Klass* sel_klass = constant_type_klass;
2653 bool fold_type_to_class = true;
2654 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2655 fold_type_to_class, CHECK_(empty));
2656 }
2657
2658 return mirror;
2659
2660 }
2661
2662 // Fall through to an error.
2663 assert(false, "unsupported mirror syntax");
2664 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2665 }
2666
2667
2668 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2669 // signature, as interpreted relative to the given class loader.
2670 // Because of class loader constraints, all method handle usage must be
2671 // consistent with this loader.
2672 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2673 Klass* accessing_klass,
2674 TRAPS) {
2675 Handle empty;
2676 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2677 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2678 int index = invoke_method_table()->hash_to_index(hash);
2679 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2680 if (spe != NULL && spe->method_type() != NULL) {
2681 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2682 return Handle(THREAD, spe->method_type());
2683 } else if (!THREAD->can_call_java()) {
2684 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2685 return Handle(); // do not attempt from within compiler, unless it was cached
2686 }
2687
2688 Handle class_loader, protection_domain;
2689 if (accessing_klass != NULL) {
2690 class_loader = Handle(THREAD, accessing_klass->class_loader());
2691 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2692 }
2693 bool can_be_cached = true;
2694 int npts = ArgumentCount(signature).size();
2695 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2696 int arg = 0;
2697 Handle rt; // the return type from the signature
2698 ResourceMark rm(THREAD);
2699 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2700 oop mirror = NULL;
2701 if (can_be_cached) {
2702 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2703 mirror = ss.as_java_mirror(Handle(), Handle(),
2704 SignatureStream::ReturnNull, CHECK_(empty));
2705 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2706 // Fall back to accessing_klass context.
2707 can_be_cached = false;
2708 }
2709 }
2710 if (!can_be_cached) {
2711 // Resolve, throwing a real error if it doesn't work.
2712 mirror = ss.as_java_mirror(class_loader, protection_domain,
2713 SignatureStream::NCDFError, CHECK_(empty));
2714 }
2715 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2716 if (ss.at_return_type())
2717 rt = Handle(THREAD, mirror);
2718 else
2719 pts->obj_at_put(arg++, mirror);
2720
2721 // Check accessibility.
2722 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2723 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2724 mirror = NULL; // safety
2725 // Emulate ConstantPool::verify_constant_pool_resolve.
2726 bool fold_type_to_class = true;
2727 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2728 fold_type_to_class, CHECK_(empty));
2729 }
2730 }
2731 assert(arg == npts, "");
2732
2733 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2734 JavaCallArguments args(Handle(THREAD, rt()));
2735 args.push_oop(pts);
2736 JavaValue result(T_OBJECT);
2737 JavaCalls::call_static(&result,
2738 SystemDictionary::MethodHandleNatives_klass(),
2739 vmSymbols::findMethodHandleType_name(),
2740 vmSymbols::findMethodHandleType_signature(),
2741 &args, CHECK_(empty));
2742 Handle method_type(THREAD, (oop) result.get_jobject());
2743
2744 if (can_be_cached) {
2745 // We can cache this MethodType inside the JVM.
2746 MutexLocker ml(SystemDictionary_lock, THREAD);
2747 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2748 if (spe == NULL)
2749 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2750 if (spe->method_type() == NULL) {
2751 spe->set_method_type(method_type());
2752 }
2753 }
2754
2755 // report back to the caller with the MethodType
2756 return method_type;
2757 }
2758
2759 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2760 Klass* accessing_klass,
2761 TRAPS) {
2762 Handle empty;
2763 ResourceMark rm(THREAD);
2764 SignatureStream ss(signature, /*is_method=*/ false);
2765 if (!ss.is_done()) {
2766 Handle class_loader, protection_domain;
2767 if (accessing_klass != NULL) {
2768 class_loader = Handle(THREAD, accessing_klass->class_loader());
2769 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2770 }
2771 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2772 ss.next();
2773 if (ss.is_done()) {
2774 return Handle(THREAD, mirror);
2775 }
2776 }
2777 return empty;
2778 }
2779
2780 // Ask Java code to find or construct a method handle constant.
2781 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2782 int ref_kind, //e.g., JVM_REF_invokeVirtual
2783 Klass* callee,
2784 Symbol* name,
2785 Symbol* signature,
2786 TRAPS) {
2787 Handle empty;
2788 if (caller == NULL) {
2789 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2790 }
2791 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2792 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2793
2794 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2795 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2796 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2797 java_lang_invoke_MemberName::set_name (mname(), name_str());
2798 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2799 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2800
2801 if (ref_kind == JVM_REF_invokeVirtual &&
2802 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2803 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2804 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2805 // They are public signature polymorphic methods, but require appendix argument
2806 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2807 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2808 } else {
2809 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2810 }
2811
2812 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2813 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2814
2815 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2816 JavaCallArguments args;
2817 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2818 args.push_int(ref_kind);
2819 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2820 args.push_oop(name_str);
2821 args.push_oop(type);
2822 JavaValue result(T_OBJECT);
2823 JavaCalls::call_static(&result,
2824 SystemDictionary::MethodHandleNatives_klass(),
2825 vmSymbols::linkMethodHandleConstant_name(),
2826 vmSymbols::linkMethodHandleConstant_signature(),
2827 &args, CHECK_(empty));
2828 return Handle(THREAD, (oop) result.get_jobject());
2829 }
2830
2831 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2832 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2833 int condy_index,
2834 Handle bootstrap_specifier,
2835 Symbol* name,
2836 Symbol* type,
2837 TRAPS) {
2838 Handle empty;
2839 Handle bsm, info;
2840 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2841 bsm = bootstrap_specifier;
2842 } else {
2843 assert(bootstrap_specifier->is_objArray(), "");
2844 objArrayOop args = (objArrayOop) bootstrap_specifier();
2845 assert(args->length() == 2, "");
2846 bsm = Handle(THREAD, args->obj_at(0));
2847 info = Handle(THREAD, args->obj_at(1));
2848 }
2849 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2850 "caller must supply a valid BSM");
2851
2852 // This should not happen. JDK code should take care of that.
2853 if (caller == NULL) {
2854 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2855 }
2856
2857 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2858
2859 // Resolve the constant type in the context of the caller class
2860 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2861 CHECK_(empty));
2862
2863 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2864 JavaCallArguments args;
2865 args.push_oop(Handle(THREAD, caller->java_mirror()));
2866 args.push_int(condy_index);
2867 args.push_oop(bsm);
2868 args.push_oop(constant_name);
2869 args.push_oop(type_mirror);
2870 args.push_oop(info);
2871 JavaValue result(T_OBJECT);
2872 JavaCalls::call_static(&result,
2873 SystemDictionary::MethodHandleNatives_klass(),
2874 vmSymbols::linkDynamicConstant_name(),
2875 vmSymbols::linkDynamicConstant_signature(),
2876 &args, CHECK_(empty));
2877
2878 return Handle(THREAD, (oop) result.get_jobject());
2879 }
2880
2881 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2882 // name and signature, as interpreted relative to the given class loader.
2883 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2884 int indy_index,
2885 Handle bootstrap_specifier,
2886 Symbol* name,
2887 Symbol* type,
2888 Handle *appendix_result,
2889 Handle *method_type_result,
2890 TRAPS) {
2891 methodHandle empty;
2892 Handle bsm, info;
2893 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2894 bsm = bootstrap_specifier;
2895 } else {
2896 objArrayOop args = (objArrayOop) bootstrap_specifier();
2897 assert(args->length() == 2, "");
2898 bsm = Handle(THREAD, args->obj_at(0));
2899 info = Handle(THREAD, args->obj_at(1));
2900 }
2901 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2902 "caller must supply a valid BSM");
2903
2904 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2905 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2906
2907 // This should not happen. JDK code should take care of that.
2908 if (caller == NULL || method_type.is_null()) {
2909 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2910 }
2911
2912 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2913 assert(appendix_box->obj_at(0) == NULL, "");
2914
2915 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2916 JavaCallArguments args;
2917 args.push_oop(Handle(THREAD, caller->java_mirror()));
2918 args.push_int(indy_index);
2919 args.push_oop(bsm);
2920 args.push_oop(method_name);
2921 args.push_oop(method_type);
2922 args.push_oop(info);
2923 args.push_oop(appendix_box);
2924 JavaValue result(T_OBJECT);
2925 JavaCalls::call_static(&result,
2926 SystemDictionary::MethodHandleNatives_klass(),
2927 vmSymbols::linkCallSite_name(),
2928 vmSymbols::linkCallSite_signature(),
2929 &args, CHECK_(empty));
2930 Handle mname(THREAD, (oop) result.get_jobject());
2931 (*method_type_result) = method_type;
2932 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2933 }
2934
2935 // Protection domain cache table handling
2936
2937 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2938 return _pd_cache_table->get(protection_domain);
2939 }
2940
2941 #if INCLUDE_CDS
2942 void SystemDictionary::reorder_dictionary_for_sharing() {
2943 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2944 }
2945 #endif
2946
2947 size_t SystemDictionary::count_bytes_for_buckets() {
2948 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2949 }
2950
2951 size_t SystemDictionary::count_bytes_for_table() {
2952 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2953 }
2954
2955 void SystemDictionary::copy_buckets(char* top, char* end) {
2956 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2957 }
2958
2959 void SystemDictionary::copy_table(char* top, char* end) {
2960 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2961 }
2962
2963 // ----------------------------------------------------------------------------
2964 void SystemDictionary::print_shared(outputStream *st) {
2965 shared_dictionary()->print_on(st);
2966 }
2967
2968 void SystemDictionary::print_on(outputStream *st) {
2969 if (shared_dictionary() != NULL) {
2970 st->print_cr("Shared Dictionary");
2971 shared_dictionary()->print_on(st);
2972 st->cr();
2973 }
2974
2975 GCMutexLocker mu(SystemDictionary_lock);
2976
2977 ClassLoaderDataGraph::print_dictionary(st);
2978
2979 // Placeholders
2980 placeholders()->print_on(st);
2981 st->cr();
2982
2983 // loader constraints - print under SD_lock
2984 constraints()->print_on(st);
2985 st->cr();
2986
2987 _pd_cache_table->print_on(st);
2988 st->cr();
2989 }
2990
2991 void SystemDictionary::verify() {
2992 guarantee(constraints() != NULL,
2993 "Verify of loader constraints failed");
2994 guarantee(placeholders()->number_of_entries() >= 0,
2995 "Verify of placeholders failed");
2996
2997 GCMutexLocker mu(SystemDictionary_lock);
2998
2999 // Verify dictionary
3000 ClassLoaderDataGraph::verify_dictionary();
3001
3002 placeholders()->verify();
3003
3004 // Verify constraint table
3005 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3006 constraints()->verify(placeholders());
3007
3008 _pd_cache_table->verify();
3009 }
3010
3011 void SystemDictionary::dump(outputStream *st, bool verbose) {
3012 assert_locked_or_safepoint(SystemDictionary_lock);
3013 if (verbose) {
3014 print_on(st);
3015 } else {
3016 if (shared_dictionary() != NULL) {
3017 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3018 }
3019 ClassLoaderDataGraph::print_dictionary_statistics(st);
3020 placeholders()->print_table_statistics(st, "Placeholder Table");
3021 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3022 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3023 }
3024 }
3025
3026 // Utility for dumping dictionaries.
3027 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3028 DCmdWithParser(output, heap),
3029 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3030 "BOOLEAN", false, "false") {
3031 _dcmdparser.add_dcmd_option(&_verbose);
3032 }
3033
3034 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3035 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3036 _verbose.value());
3037 VMThread::execute(&dumper);
3038 }
3039
3040 int SystemDictionaryDCmd::num_arguments() {
3041 ResourceMark rm;
3042 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3043 if (dcmd != NULL) {
3044 DCmdMark mark(dcmd);
3045 return dcmd->_dcmdparser.num_arguments();
3046 } else {
3047 return 0;
3048 }
3049 }
3050
3051 class CombineDictionariesClosure : public CLDClosure {
3052 private:
3053 Dictionary* _master_dictionary;
3054 public:
3055 CombineDictionariesClosure(Dictionary* master_dictionary) :
3056 _master_dictionary(master_dictionary) {}
3057 void do_cld(ClassLoaderData* cld) {
3058 ResourceMark rm;
3059 if (cld->is_anonymous()) {
3060 return;
3061 }
3062 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3063 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3064 Dictionary* curr_dictionary = cld->dictionary();
3065 DictionaryEntry* p = curr_dictionary->bucket(i);
3066 while (p != NULL) {
3067 Symbol* name = p->instance_klass()->name();
3068 unsigned int d_hash = _master_dictionary->compute_hash(name);
3069 int d_index = _master_dictionary->hash_to_index(d_hash);
3070 DictionaryEntry* next = p->next();
3071 if (p->literal()->class_loader_data() != cld) {
3072 // This is an initiating class loader entry; don't use it
3073 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3074 curr_dictionary->free_entry(p);
3075 } else {
3076 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3077 curr_dictionary->unlink_entry(p);
3078 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3079 _master_dictionary->add_entry(d_index, p);
3080 }
3081 p = next;
3082 }
3083 *curr_dictionary->bucket_addr(i) = NULL;
3084 }
3085 }
3086 }
3087 };
3088
3089 // Combining platform and system loader dictionaries into boot loader dictionary.
3090 // During run time, we only have one shared dictionary.
3091 void SystemDictionary::combine_shared_dictionaries() {
3092 assert(DumpSharedSpaces, "dump time only");
3093 // If AppCDS isn't enabled, we only dump the classes in the boot loader dictionary
3094 // into the shared archive.
3095 if (UseAppCDS) {
3096 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3097 CombineDictionariesClosure cdc(master_dictionary);
3098 ClassLoaderDataGraph::cld_do(&cdc);
3099 }
3100
3101 // These tables are no longer valid or necessary. Keeping them around will
3102 // cause SystemDictionary::verify() to fail. Let's empty them.
3103 _placeholders = new PlaceholderTable(_placeholder_table_size);
3104 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3105
3106 NOT_PRODUCT(SystemDictionary::verify());
3107 }
3108
3109 // Return string to give helpful intformation about a classloader.
3110 // Caller needs ResourceMark.
3111 const char* SystemDictionary::loader_name(const oop loader) {
3112 #if INCLUDE_CDS
3113 if (DumpSharedSpaces) {
3114 // Describe_external() calls assert(is_instance...) in various places,
3115 // which may fail with DumpSharedSpaces.
3116 if ((loader) == NULL) return "<bootloader>";
3117 return InstanceKlass::cast((loader)->klass())->name()->as_C_string();
3118 }
3119 #endif
3120 return java_lang_ClassLoader::describe_external(loader);
3121 }
3122
3123 // caller needs ResourceMark
3124 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3125 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3126 SystemDictionary::loader_name(loader_data->class_loader()));
3127 }