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/gcTraceTime.inline.hpp"
47 #include "gc/shared/oopStorage.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "jfr/jfr.hpp"
51 #include "jfr/jfrEvents.hpp"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/filemap.hpp"
55 #include "memory/metaspaceClosure.hpp"
56 #include "memory/oopFactory.hpp"
57 #include "memory/resourceArea.hpp"
58 #include "oops/access.inline.hpp"
59 #include "oops/instanceKlass.hpp"
60 #include "oops/instanceRefKlass.hpp"
61 #include "oops/klass.inline.hpp"
62 #include "oops/method.inline.hpp"
63 #include "oops/methodData.hpp"
64 #include "oops/objArrayKlass.hpp"
65 #include "oops/objArrayOop.inline.hpp"
66 #include "oops/oop.inline.hpp"
67 #include "oops/symbol.hpp"
68 #include "oops/typeArrayKlass.hpp"
69 #include "prims/jvmtiEnvBase.hpp"
70 #include "prims/resolvedMethodTable.hpp"
71 #include "prims/methodHandles.hpp"
72 #include "runtime/arguments.hpp"
73 #include "runtime/arguments_ext.hpp"
74 #include "runtime/biasedLocking.hpp"
75 #include "runtime/fieldType.hpp"
76 #include "runtime/handles.inline.hpp"
77 #include "runtime/java.hpp"
78 #include "runtime/javaCalls.hpp"
79 #include "runtime/mutexLocker.hpp"
80 #include "runtime/orderAccess.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #include "utilities/ticks.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JVMCI
92 #include "jvmci/jvmciRuntime.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 Dictionary* SystemDictionary::_shared_dictionary = NULL;
97 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
98 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
99 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
100 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
101
102 int SystemDictionary::_number_of_modifications = 0;
103 oop SystemDictionary::_system_loader_lock_obj = NULL;
104
105 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
106 = { NULL /*, NULL...*/ };
107
108 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
109
110 oop SystemDictionary::_java_system_loader = NULL;
111 oop SystemDictionary::_java_platform_loader = NULL;
112
113 bool SystemDictionary::_has_checkPackageAccess = false;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
118
119 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
120
121
122 // ----------------------------------------------------------------------------
123 // Java-level SystemLoader and PlatformLoader
124
125 oop SystemDictionary::java_system_loader() {
126 return _java_system_loader;
127 }
128
129 oop SystemDictionary::java_platform_loader() {
130 return _java_platform_loader;
131 }
132
133 void SystemDictionary::compute_java_loaders(TRAPS) {
134 JavaValue result(T_OBJECT);
135 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
136 JavaCalls::call_static(&result,
137 class_loader_klass,
138 vmSymbols::getSystemClassLoader_name(),
139 vmSymbols::void_classloader_signature(),
140 CHECK);
141
142 _java_system_loader = (oop)result.get_jobject();
143
144 JavaCalls::call_static(&result,
145 class_loader_klass,
146 vmSymbols::getPlatformClassLoader_name(),
147 vmSymbols::void_classloader_signature(),
148 CHECK);
149
150 _java_platform_loader = (oop)result.get_jobject();
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 oopDesc::equals(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_array_class_or_null or resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 if (FieldType::is_array(class_name)) {
251 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
252 } else {
253 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
254 }
255 }
256
257 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
258 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
259 Handle class_loader,
260 Handle protection_domain,
261 TRAPS) {
262 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
263 if (FieldType::is_obj(class_name)) {
264 ResourceMark rm(THREAD);
265 // Ignore wrapping L and ;.
266 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
267 class_name->utf8_length() - 2, CHECK_NULL);
268 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
269 } else {
270 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
271 }
272 }
273
274 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
275 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
276 }
277
278 // Forwards to resolve_instance_class_or_null
279
280 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
281 Handle class_loader,
282 Handle protection_domain,
283 TRAPS) {
284 assert(FieldType::is_array(class_name), "must be array");
285 Klass* k = NULL;
286 FieldArrayInfo fd;
287 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
288 // of this call
289 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
290 if (t == T_OBJECT) {
291 // naked oop "k" is OK here -- we assign back into it
292 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
293 class_loader,
294 protection_domain,
295 CHECK_NULL);
296 if (k != NULL) {
297 k = k->array_klass(fd.dimension(), CHECK_NULL);
298 }
299 } else {
300 k = Universe::typeArrayKlassObj(t);
301 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
302 }
303 return k;
304 }
305
306
307 // Must be called for any super-class or super-interface resolution
308 // during class definition to allow class circularity checking
309 // super-interface callers:
310 // parse_interfaces - for defineClass & jvmtiRedefineClasses
311 // super-class callers:
312 // ClassFileParser - for defineClass & jvmtiRedefineClasses
313 // load_shared_class - while loading a class from shared archive
314 // resolve_instance_class_or_null:
315 // via: handle_parallel_super_load
316 // when resolving a class that has an existing placeholder with
317 // a saved superclass [i.e. a defineClass is currently in progress]
318 // if another thread is trying to resolve the class, it must do
319 // super-class checks on its own thread to catch class circularity
320 // This last call is critical in class circularity checking for cases
321 // where classloading is delegated to different threads and the
322 // classloader lock is released.
323 // Take the case: Base->Super->Base
324 // 1. If thread T1 tries to do a defineClass of class Base
325 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
326 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
327 // so it tries to load Super
328 // 3. If we load the class internally, or user classloader uses same thread
329 // loadClassFromxxx or defineClass via parseClassFile Super ...
330 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
331 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
332 // 3.4 calls resolve_super_or_fail Base
333 // 3.5 finds T1,Base -> throws class circularity
334 //OR 4. If T2 tries to resolve Super via defineClass Super ...
335 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
336 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
337 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
338 // 4.4 finds T2, Super -> throws class circularity
339 // Must be called, even if superclass is null, since this is
340 // where the placeholder entry is created which claims this
341 // thread is loading this class/classloader.
342 // Be careful when modifying this code: once you have run
343 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
344 // you need to find_and_remove it before returning.
345 // So be careful to not exit with a CHECK_ macro betweeen these calls.
346 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
347 Symbol* super_name,
348 Handle class_loader,
349 Handle protection_domain,
350 bool is_superclass,
351 TRAPS) {
352 assert(!FieldType::is_array(super_name), "invalid super class name");
353 #if INCLUDE_CDS
354 if (DumpSharedSpaces) {
355 // Special processing for CDS dump time.
356 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
357 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
358 if (k) {
359 return k;
360 }
361 }
362 #endif // INCLUDE_CDS
363
364 // Double-check, if child class is already loaded, just return super-class,interface
365 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
366 // dictionary.
367 // Make sure there's a placeholder for the *child* before resolving.
368 // Used as a claim that this thread is currently loading superclass/classloader
369 // Used here for ClassCircularity checks and also for heap verification
370 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
371 // Must check ClassCircularity before checking if super class is already loaded.
372 //
373 // We might not already have a placeholder if this child_name was
374 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
375 // the name of the class might not be known until the stream is actually
376 // parsed.
377 // Bugs 4643874, 4715493
378
379 ClassLoaderData* loader_data = class_loader_data(class_loader);
380 Dictionary* dictionary = loader_data->dictionary();
381 unsigned int d_hash = dictionary->compute_hash(child_name);
382 unsigned int p_hash = placeholders()->compute_hash(child_name);
383 int p_index = placeholders()->hash_to_index(p_hash);
384 // can't throw error holding a lock
385 bool child_already_loaded = false;
386 bool throw_circularity_error = false;
387 {
388 MutexLocker mu(SystemDictionary_lock, THREAD);
389 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
390 InstanceKlass* quicksuperk;
391 // to support // loading: if child done loading, just return superclass
392 // if super_name, & class_loader don't match:
393 // if initial define, SD update will give LinkageError
394 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
395 // so we don't throw an exception here.
396 // see: nsk redefclass014 & java.lang.instrument Instrument032
397 if ((childk != NULL ) && (is_superclass) &&
398 ((quicksuperk = childk->java_super()) != NULL) &&
399 ((quicksuperk->name() == super_name) &&
400 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
401 return quicksuperk;
402 } else {
403 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
404 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
405 throw_circularity_error = true;
406 }
407 }
408 if (!throw_circularity_error) {
409 // Be careful not to exit resolve_super
410 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
411 }
412 }
413 if (throw_circularity_error) {
414 ResourceMark rm(THREAD);
415 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
416 }
417
418 // java.lang.Object should have been found above
419 assert(super_name != NULL, "null super class for resolving");
420 // Resolve the super class or interface, check results on return
421 InstanceKlass* superk =
422 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
423 class_loader,
424 protection_domain,
425 THREAD);
426
427 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
428 // It is no longer necessary to keep the placeholder table alive until update_dictionary
429 // or error. GC used to walk the placeholder table as strong roots.
430 // The instanceKlass is kept alive because the class loader is on the stack,
431 // which keeps the loader_data alive, as well as all instanceKlasses in
432 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
433 {
434 MutexLocker mu(SystemDictionary_lock, THREAD);
435 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
436 SystemDictionary_lock->notify_all();
437 }
438 if (HAS_PENDING_EXCEPTION || superk == NULL) {
439 // can null superk
440 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
441 assert(k == NULL || k == superk, "must be");
442 if (k == NULL) {
443 superk = NULL;
444 }
445 }
446
447 return superk;
448 }
449
450 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
451 Handle class_loader,
452 Handle protection_domain,
453 TRAPS) {
454 if(!has_checkPackageAccess()) return;
455
456 // Now we have to call back to java to check if the initating class has access
457 JavaValue result(T_VOID);
458 LogTarget(Debug, protectiondomain) lt;
459 if (lt.is_enabled()) {
460 ResourceMark rm;
461 // Print out trace information
462 LogStream ls(lt);
463 ls.print_cr("Checking package access");
464 if (class_loader() != NULL) {
465 ls.print("class loader: ");
466 class_loader()->print_value_on(&ls);
467 } else {
468 ls.print_cr("class loader: NULL");
469 }
470 if (protection_domain() != NULL) {
471 ls.print(" protection domain: ");
472 protection_domain()->print_value_on(&ls);
473 } else {
474 ls.print_cr(" protection domain: NULL");
475 }
476 ls.print(" loading: "); klass->print_value_on(&ls);
477 ls.cr();
478 }
479
480 // This handle and the class_loader handle passed in keeps this class from
481 // being unloaded through several GC points.
482 // The class_loader handle passed in is the initiating loader.
483 Handle mirror(THREAD, klass->java_mirror());
484
485 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
486 JavaCalls::call_special(&result,
487 class_loader,
488 system_loader,
489 vmSymbols::checkPackageAccess_name(),
490 vmSymbols::class_protectiondomain_signature(),
491 mirror,
492 protection_domain,
493 THREAD);
494
495 if (HAS_PENDING_EXCEPTION) {
496 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
497 } else {
498 log_debug(protectiondomain)("granted");
499 }
500
501 if (HAS_PENDING_EXCEPTION) return;
502
503 // If no exception has been thrown, we have validated the protection domain
504 // Insert the protection domain of the initiating class into the set.
505 {
506 ClassLoaderData* loader_data = class_loader_data(class_loader);
507 Dictionary* dictionary = loader_data->dictionary();
508
509 Symbol* kn = klass->name();
510 unsigned int d_hash = dictionary->compute_hash(kn);
511
512 MutexLocker mu(SystemDictionary_lock, THREAD);
513 int d_index = dictionary->hash_to_index(d_hash);
514 dictionary->add_protection_domain(d_index, d_hash, klass,
515 protection_domain, THREAD);
516 }
517 }
518
519 // We only get here if this thread finds that another thread
520 // has already claimed the placeholder token for the current operation,
521 // but that other thread either never owned or gave up the
522 // object lock
523 // Waits on SystemDictionary_lock to indicate placeholder table updated
524 // On return, caller must recheck placeholder table state
525 //
526 // We only get here if
527 // 1) custom classLoader, i.e. not bootstrap classloader
528 // 2) custom classLoader has broken the class loader objectLock
529 // so another thread got here in parallel
530 //
531 // lockObject must be held.
532 // Complicated dance due to lock ordering:
533 // Must first release the classloader object lock to
534 // allow initial definer to complete the class definition
535 // and to avoid deadlock
536 // Reclaim classloader lock object with same original recursion count
537 // Must release SystemDictionary_lock after notify, since
538 // class loader lock must be claimed before SystemDictionary_lock
539 // to prevent deadlocks
540 //
541 // The notify allows applications that did an untimed wait() on
542 // the classloader object lock to not hang.
543 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
544 assert_lock_strong(SystemDictionary_lock);
545
546 bool calledholdinglock
547 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
548 assert(calledholdinglock,"must hold lock for notify");
549 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
550 ObjectSynchronizer::notifyall(lockObject, THREAD);
551 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
552 SystemDictionary_lock->wait();
553 SystemDictionary_lock->unlock();
554 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
555 SystemDictionary_lock->lock();
556 }
557
558 // If the class in is in the placeholder table, class loading is in progress
559 // For cases where the application changes threads to load classes, it
560 // is critical to ClassCircularity detection that we try loading
561 // the superclass on the same thread internally, so we do parallel
562 // super class loading here.
563 // This also is critical in cases where the original thread gets stalled
564 // even in non-circularity situations.
565 // Note: must call resolve_super_or_fail even if null super -
566 // to force placeholder entry creation for this class for circularity detection
567 // Caller must check for pending exception
568 // Returns non-null Klass* if other thread has completed load
569 // and we are done,
570 // If return null Klass* and no pending exception, the caller must load the class
571 InstanceKlass* SystemDictionary::handle_parallel_super_load(
572 Symbol* name, Symbol* superclassname, Handle class_loader,
573 Handle protection_domain, Handle lockObject, TRAPS) {
574
575 ClassLoaderData* loader_data = class_loader_data(class_loader);
576 Dictionary* dictionary = loader_data->dictionary();
577 unsigned int d_hash = dictionary->compute_hash(name);
578 unsigned int p_hash = placeholders()->compute_hash(name);
579 int p_index = placeholders()->hash_to_index(p_hash);
580
581 // superk is not used, resolve_super called for circularity check only
582 // This code is reached in two situations. One if this thread
583 // is loading the same class twice (e.g. ClassCircularity, or
584 // java.lang.instrument).
585 // The second is if another thread started the resolve_super first
586 // and has not yet finished.
587 // In both cases the original caller will clean up the placeholder
588 // entry on error.
589 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
590 superclassname,
591 class_loader,
592 protection_domain,
593 true,
594 CHECK_NULL);
595
596 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
597 // Serial class loaders and bootstrap classloader do wait for superclass loads
598 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
599 MutexLocker mu(SystemDictionary_lock, THREAD);
600 // Check if classloading completed while we were loading superclass or waiting
601 return find_class(d_hash, name, dictionary);
602 }
603
604 // must loop to both handle other placeholder updates
605 // and spurious notifications
606 bool super_load_in_progress = true;
607 PlaceholderEntry* placeholder;
608 while (super_load_in_progress) {
609 MutexLocker mu(SystemDictionary_lock, THREAD);
610 // Check if classloading completed while we were loading superclass or waiting
611 InstanceKlass* check = find_class(d_hash, name, dictionary);
612 if (check != NULL) {
613 // Klass is already loaded, so just return it
614 return check;
615 } else {
616 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
617 if (placeholder && placeholder->super_load_in_progress() ){
618 // We only get here if the application has released the
619 // classloader lock when another thread was in the middle of loading a
620 // superclass/superinterface for this class, and now
621 // this thread is also trying to load this class.
622 // To minimize surprises, the first thread that started to
623 // load a class should be the one to complete the loading
624 // with the classfile it initially expected.
625 // This logic has the current thread wait once it has done
626 // all the superclass/superinterface loading it can, until
627 // the original thread completes the class loading or fails
628 // If it completes we will use the resulting InstanceKlass
629 // which we will find below in the systemDictionary.
630 // We also get here for parallel bootstrap classloader
631 if (class_loader.is_null()) {
632 SystemDictionary_lock->wait();
633 } else {
634 double_lock_wait(lockObject, THREAD);
635 }
636 } else {
637 // If not in SD and not in PH, other thread's load must have failed
638 super_load_in_progress = false;
639 }
640 }
641 }
642 return NULL;
643 }
644
645 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
646 assert(event != NULL, "invariant");
647 assert(k != NULL, "invariant");
648 assert(event->should_commit(), "invariant");
649 event->set_loadedClass(k);
650 event->set_definingClassLoader(k->class_loader_data());
651 event->set_initiatingClassLoader(init_cld);
652 event->commit();
653 }
654
655
656 // Be careful when modifying this code: once you have run
657 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
658 // you need to find_and_remove it before returning.
659 // So be careful to not exit with a CHECK_ macro betweeen these calls.
660 //
661 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
662 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
663 Handle class_loader,
664 Handle protection_domain,
665 TRAPS) {
666 assert(name != NULL && !FieldType::is_array(name) &&
667 !FieldType::is_obj(name), "invalid class name");
668
669 EventClassLoad class_load_start_event;
670
671 HandleMark hm(THREAD);
672
673 // Fix for 4474172; see evaluation for more details
674 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
675 ClassLoaderData* loader_data = register_loader(class_loader);
676 Dictionary* dictionary = loader_data->dictionary();
677 unsigned int d_hash = dictionary->compute_hash(name);
678
679 // Do lookup to see if class already exist and the protection domain
680 // has the right access
681 // This call uses find which checks protection domain already matches
682 // All subsequent calls use find_class, and set has_loaded_class so that
683 // before we return a result we call out to java to check for valid protection domain
684 // to allow returning the Klass* and add it to the pd_set if it is valid
685 {
686 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
687 if (probe != NULL) return probe;
688 }
689
690 // Non-bootstrap class loaders will call out to class loader and
691 // define via jvm/jni_DefineClass which will acquire the
692 // class loader object lock to protect against multiple threads
693 // defining the class in parallel by accident.
694 // This lock must be acquired here so the waiter will find
695 // any successful result in the SystemDictionary and not attempt
696 // the define.
697 // ParallelCapable Classloaders and the bootstrap classloader
698 // do not acquire lock here.
699 bool DoObjectLock = true;
700 if (is_parallelCapable(class_loader)) {
701 DoObjectLock = false;
702 }
703
704 unsigned int p_hash = placeholders()->compute_hash(name);
705 int p_index = placeholders()->hash_to_index(p_hash);
706
707 // Class is not in SystemDictionary so we have to do loading.
708 // Make sure we are synchronized on the class loader before we proceed
709 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
710 check_loader_lock_contention(lockObject, THREAD);
711 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
712
713 // Check again (after locking) if class already exist in SystemDictionary
714 bool class_has_been_loaded = false;
715 bool super_load_in_progress = false;
716 bool havesupername = false;
717 InstanceKlass* k = NULL;
718 PlaceholderEntry* placeholder;
719 Symbol* superclassname = NULL;
720
721 assert(THREAD->can_call_java(),
722 "can not load classes with compiler thread: class=%s, classloader=%s",
723 name->as_C_string(),
724 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
725 {
726 MutexLocker mu(SystemDictionary_lock, THREAD);
727 InstanceKlass* check = find_class(d_hash, name, dictionary);
728 if (check != NULL) {
729 // InstanceKlass is already loaded, so just return it
730 class_has_been_loaded = true;
731 k = check;
732 } else {
733 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
734 if (placeholder && placeholder->super_load_in_progress()) {
735 super_load_in_progress = true;
736 if (placeholder->havesupername() == true) {
737 superclassname = placeholder->supername();
738 havesupername = true;
739 }
740 }
741 }
742 }
743
744 // If the class is in the placeholder table, class loading is in progress
745 if (super_load_in_progress && havesupername==true) {
746 k = handle_parallel_super_load(name,
747 superclassname,
748 class_loader,
749 protection_domain,
750 lockObject, THREAD);
751 if (HAS_PENDING_EXCEPTION) {
752 return NULL;
753 }
754 if (k != NULL) {
755 class_has_been_loaded = true;
756 }
757 }
758
759 bool throw_circularity_error = false;
760 if (!class_has_been_loaded) {
761 bool load_instance_added = false;
762
763 // add placeholder entry to record loading instance class
764 // Five cases:
765 // All cases need to prevent modifying bootclasssearchpath
766 // in parallel with a classload of same classname
767 // Redefineclasses uses existence of the placeholder for the duration
768 // of the class load to prevent concurrent redefinition of not completely
769 // defined classes.
770 // case 1. traditional classloaders that rely on the classloader object lock
771 // - no other need for LOAD_INSTANCE
772 // case 2. traditional classloaders that break the classloader object lock
773 // as a deadlock workaround. Detection of this case requires that
774 // this check is done while holding the classloader object lock,
775 // and that lock is still held when calling classloader's loadClass.
776 // For these classloaders, we ensure that the first requestor
777 // completes the load and other requestors wait for completion.
778 // case 3. Bootstrap classloader - don't own objectLocker
779 // This classloader supports parallelism at the classloader level,
780 // but only allows a single load of a class/classloader pair.
781 // No performance benefit and no deadlock issues.
782 // case 4. parallelCapable user level classloaders - without objectLocker
783 // Allow parallel classloading of a class/classloader pair
784
785 {
786 MutexLocker mu(SystemDictionary_lock, THREAD);
787 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
788 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
789 if (oldprobe) {
790 // only need check_seen_thread once, not on each loop
791 // 6341374 java/lang/Instrument with -Xcomp
792 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
793 throw_circularity_error = true;
794 } else {
795 // case 1: traditional: should never see load_in_progress.
796 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
797
798 // case 3: bootstrap classloader: prevent futile classloading,
799 // wait on first requestor
800 if (class_loader.is_null()) {
801 SystemDictionary_lock->wait();
802 } else {
803 // case 2: traditional with broken classloader lock. wait on first
804 // requestor.
805 double_lock_wait(lockObject, THREAD);
806 }
807 // Check if classloading completed while we were waiting
808 InstanceKlass* check = find_class(d_hash, name, dictionary);
809 if (check != NULL) {
810 // Klass is already loaded, so just return it
811 k = check;
812 class_has_been_loaded = true;
813 }
814 // check if other thread failed to load and cleaned up
815 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
816 }
817 }
818 }
819 }
820 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
821 // case 4: parallelCapable: allow competing threads to try
822 // LOAD_INSTANCE in parallel
823
824 if (!throw_circularity_error && !class_has_been_loaded) {
825 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
826 load_instance_added = true;
827 // For class loaders that do not acquire the classloader object lock,
828 // if they did not catch another thread holding LOAD_INSTANCE,
829 // need a check analogous to the acquire ObjectLocker/find_class
830 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
831 // one final check if the load has already completed
832 // class loaders holding the ObjectLock shouldn't find the class here
833 InstanceKlass* check = find_class(d_hash, name, dictionary);
834 if (check != NULL) {
835 // Klass is already loaded, so return it after checking/adding protection domain
836 k = check;
837 class_has_been_loaded = true;
838 }
839 }
840 }
841
842 // must throw error outside of owning lock
843 if (throw_circularity_error) {
844 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
845 ResourceMark rm(THREAD);
846 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
847 }
848
849 if (!class_has_been_loaded) {
850
851 // Do actual loading
852 k = load_instance_class(name, class_loader, THREAD);
853
854 // If everything was OK (no exceptions, no null return value), and
855 // class_loader is NOT the defining loader, do a little more bookkeeping.
856 if (!HAS_PENDING_EXCEPTION && k != NULL &&
857 !oopDesc::equals(k->class_loader(), class_loader())) {
858
859 check_constraints(d_hash, k, class_loader, false, THREAD);
860
861 // Need to check for a PENDING_EXCEPTION again; check_constraints
862 // can throw and doesn't use the CHECK macro.
863 if (!HAS_PENDING_EXCEPTION) {
864 { // Grabbing the Compile_lock prevents systemDictionary updates
865 // during compilations.
866 MutexLocker mu(Compile_lock, THREAD);
867 update_dictionary(d_hash, p_index, p_hash,
868 k, class_loader, THREAD);
869 }
870
871 if (JvmtiExport::should_post_class_load()) {
872 Thread *thread = THREAD;
873 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
874 JvmtiExport::post_class_load((JavaThread *) thread, k);
875 }
876 }
877 }
878 } // load_instance_class
879
880 if (load_instance_added == true) {
881 // clean up placeholder entries for LOAD_INSTANCE success or error
882 // This brackets the SystemDictionary updates for both defining
883 // and initiating loaders
884 MutexLocker mu(SystemDictionary_lock, THREAD);
885 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
886 SystemDictionary_lock->notify_all();
887 }
888 }
889
890 if (HAS_PENDING_EXCEPTION || k == NULL) {
891 return NULL;
892 }
893 if (class_load_start_event.should_commit()) {
894 post_class_load_event(&class_load_start_event, k, loader_data);
895 }
896 #ifdef ASSERT
897 {
898 ClassLoaderData* loader_data = k->class_loader_data();
899 MutexLocker mu(SystemDictionary_lock, THREAD);
900 InstanceKlass* kk = find_class(name, loader_data);
901 assert(kk == k, "should be present in dictionary");
902 }
903 #endif
904
905 // return if the protection domain in NULL
906 if (protection_domain() == NULL) return k;
907
908 // Check the protection domain has the right access
909 if (dictionary->is_valid_protection_domain(d_hash, name,
910 protection_domain)) {
911 return k;
912 }
913
914 // Verify protection domain. If it fails an exception is thrown
915 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
916
917 return k;
918 }
919
920
921 // This routine does not lock the system dictionary.
922 //
923 // Since readers don't hold a lock, we must make sure that system
924 // dictionary entries are only removed at a safepoint (when only one
925 // thread is running), and are added to in a safe way (all links must
926 // be updated in an MT-safe manner).
927 //
928 // Callers should be aware that an entry could be added just after
929 // _dictionary->bucket(index) is read here, so the caller will not see
930 // the new entry.
931
932 Klass* SystemDictionary::find(Symbol* class_name,
933 Handle class_loader,
934 Handle protection_domain,
935 TRAPS) {
936
937 // The result of this call should be consistent with the result
938 // of the call to resolve_instance_class_or_null().
939 // See evaluation 6790209 and 4474172 for more details.
940 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
941 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
942
943 if (loader_data == NULL) {
944 // If the ClassLoaderData has not been setup,
945 // then the class loader has no entries in the dictionary.
946 return NULL;
947 }
948
949 Dictionary* dictionary = loader_data->dictionary();
950 unsigned int d_hash = dictionary->compute_hash(class_name);
951 return dictionary->find(d_hash, class_name,
952 protection_domain);
953 }
954
955
956 // Look for a loaded instance or array klass by name. Do not do any loading.
957 // return NULL in case of error.
958 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
959 Handle class_loader,
960 Handle protection_domain,
961 TRAPS) {
962 Klass* k = NULL;
963 assert(class_name != NULL, "class name must be non NULL");
964
965 if (FieldType::is_array(class_name)) {
966 // The name refers to an array. Parse the name.
967 // dimension and object_key in FieldArrayInfo are assigned as a
968 // side-effect of this call
969 FieldArrayInfo fd;
970 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
971 if (t != T_OBJECT) {
972 k = Universe::typeArrayKlassObj(t);
973 } else {
974 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
975 }
976 if (k != NULL) {
977 k = k->array_klass_or_null(fd.dimension());
978 }
979 } else {
980 k = find(class_name, class_loader, protection_domain, THREAD);
981 }
982 return k;
983 }
984
985 // Note: this method is much like resolve_from_stream, but
986 // does not publish the classes via the SystemDictionary.
987 // Handles unsafe_DefineAnonymousClass and redefineclasses
988 // RedefinedClasses do not add to the class hierarchy
989 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
990 Handle class_loader,
991 Handle protection_domain,
992 ClassFileStream* st,
993 const InstanceKlass* unsafe_anonymous_host,
994 GrowableArray<Handle>* cp_patches,
995 TRAPS) {
996
997 EventClassLoad class_load_start_event;
998
999 ClassLoaderData* loader_data;
1000 if (unsafe_anonymous_host != NULL) {
1001 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1002 // as the unsafe_anonymous_host
1003 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1004 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1005 } else {
1006 loader_data = ClassLoaderData::class_loader_data(class_loader());
1007 }
1008
1009 assert(st != NULL, "invariant");
1010 assert(st->need_verify(), "invariant");
1011
1012 // Parse stream and create a klass.
1013 // Note that we do this even though this klass might
1014 // already be present in the SystemDictionary, otherwise we would not
1015 // throw potential ClassFormatErrors.
1016
1017 InstanceKlass* k = KlassFactory::create_from_stream(st,
1018 class_name,
1019 loader_data,
1020 protection_domain,
1021 unsafe_anonymous_host,
1022 cp_patches,
1023 CHECK_NULL);
1024
1025 if (unsafe_anonymous_host != NULL && k != NULL) {
1026 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1027 // so that they can be unloaded when the mirror is no longer referenced.
1028 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1029
1030 {
1031 MutexLocker mu_r(Compile_lock, THREAD);
1032
1033 // Add to class hierarchy, initialize vtables, and do possible
1034 // deoptimizations.
1035 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1036
1037 // But, do not add to dictionary.
1038
1039 // compiled code dependencies need to be validated anyway
1040 notice_modification();
1041 }
1042
1043 // Rewrite and patch constant pool here.
1044 k->link_class(CHECK_NULL);
1045 if (cp_patches != NULL) {
1046 k->constants()->patch_resolved_references(cp_patches);
1047 }
1048
1049 // If it's anonymous, initialize it now, since nobody else will.
1050 k->eager_initialize(CHECK_NULL);
1051
1052 // notify jvmti
1053 if (JvmtiExport::should_post_class_load()) {
1054 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1055 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1056 }
1057 if (class_load_start_event.should_commit()) {
1058 post_class_load_event(&class_load_start_event, k, loader_data);
1059 }
1060 }
1061 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1062 "cp_patches only found with unsafe_anonymous_host");
1063
1064 return k;
1065 }
1066
1067 // Add a klass to the system from a stream (called by jni_DefineClass and
1068 // JVM_DefineClass).
1069 // Note: class_name can be NULL. In that case we do not know the name of
1070 // the class until we have parsed the stream.
1071
1072 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1073 Handle class_loader,
1074 Handle protection_domain,
1075 ClassFileStream* st,
1076 TRAPS) {
1077
1078 HandleMark hm(THREAD);
1079
1080 // Classloaders that support parallelism, e.g. bootstrap classloader,
1081 // do not acquire lock here
1082 bool DoObjectLock = true;
1083 if (is_parallelCapable(class_loader)) {
1084 DoObjectLock = false;
1085 }
1086
1087 ClassLoaderData* loader_data = register_loader(class_loader);
1088
1089 // Make sure we are synchronized on the class loader before we proceed
1090 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1091 check_loader_lock_contention(lockObject, THREAD);
1092 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1093
1094 assert(st != NULL, "invariant");
1095
1096 // Parse the stream and create a klass.
1097 // Note that we do this even though this klass might
1098 // already be present in the SystemDictionary, otherwise we would not
1099 // throw potential ClassFormatErrors.
1100 InstanceKlass* k = NULL;
1101
1102 #if INCLUDE_CDS
1103 if (!DumpSharedSpaces) {
1104 k = SystemDictionaryShared::lookup_from_stream(class_name,
1105 class_loader,
1106 protection_domain,
1107 st,
1108 CHECK_NULL);
1109 }
1110 #endif
1111
1112 if (k == NULL) {
1113 if (st->buffer() == NULL) {
1114 return NULL;
1115 }
1116 k = KlassFactory::create_from_stream(st,
1117 class_name,
1118 loader_data,
1119 protection_domain,
1120 NULL, // unsafe_anonymous_host
1121 NULL, // cp_patches
1122 CHECK_NULL);
1123 }
1124
1125 assert(k != NULL, "no klass created");
1126 Symbol* h_name = k->name();
1127 assert(class_name == NULL || class_name == h_name, "name mismatch");
1128
1129 // Add class just loaded
1130 // If a class loader supports parallel classloading handle parallel define requests
1131 // find_or_define_instance_class may return a different InstanceKlass
1132 if (is_parallelCapable(class_loader)) {
1133 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1134 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1135 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1136 assert(defined_k != NULL, "Should have a klass if there's no exception");
1137 loader_data->add_to_deallocate_list(k);
1138 k = defined_k;
1139 }
1140 } else {
1141 define_instance_class(k, THREAD);
1142 }
1143
1144 // If defining the class throws an exception register 'k' for cleanup.
1145 if (HAS_PENDING_EXCEPTION) {
1146 assert(k != NULL, "Must have an instance klass here!");
1147 loader_data->add_to_deallocate_list(k);
1148 return NULL;
1149 }
1150
1151 // Make sure we have an entry in the SystemDictionary on success
1152 debug_only( {
1153 MutexLocker mu(SystemDictionary_lock, THREAD);
1154
1155 Klass* check = find_class(h_name, k->class_loader_data());
1156 assert(check == k, "should be present in the dictionary");
1157 } );
1158
1159 return k;
1160 }
1161
1162 #if INCLUDE_CDS
1163 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1164 int number_of_entries) {
1165 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1166 "bad shared dictionary size.");
1167 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1168 _shared_dictionary_size, t, number_of_entries);
1169 }
1170
1171
1172 // If there is a shared dictionary, then find the entry for the
1173 // given shared system class, if any.
1174
1175 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1176 if (shared_dictionary() != NULL) {
1177 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1178 int d_index = shared_dictionary()->hash_to_index(d_hash);
1179
1180 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1181 } else {
1182 return NULL;
1183 }
1184 }
1185
1186
1187 // Load a class from the shared spaces (found through the shared system
1188 // dictionary). Force the superclass and all interfaces to be loaded.
1189 // Update the class definition to include sibling classes and no
1190 // subclasses (yet). [Classes in the shared space are not part of the
1191 // object hierarchy until loaded.]
1192
1193 InstanceKlass* SystemDictionary::load_shared_class(
1194 Symbol* class_name, Handle class_loader, TRAPS) {
1195 InstanceKlass* ik = find_shared_class(class_name);
1196 // Make sure we only return the boot class for the NULL classloader.
1197 if (ik != NULL &&
1198 ik->is_shared_boot_class() && class_loader.is_null()) {
1199 Handle protection_domain;
1200 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1201 }
1202 return NULL;
1203 }
1204
1205 // Check if a shared class can be loaded by the specific classloader:
1206 //
1207 // NULL classloader:
1208 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1209 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1210 // be defined in an unnamed module.
1211 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1212 InstanceKlass* ik,
1213 Handle class_loader, TRAPS) {
1214 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1215 "Cannot use sharing if java.base is patched");
1216 ResourceMark rm;
1217 int path_index = ik->shared_classpath_index();
1218 ClassLoaderData* loader_data = class_loader_data(class_loader);
1219 if (path_index < 0) {
1220 // path_index < 0 indicates that the class is intended for a custom loader
1221 // and should not be loaded by boot/platform/app loaders
1222 if (loader_data->is_builtin_class_loader_data()) {
1223 return false;
1224 } else {
1225 return true;
1226 }
1227 }
1228 SharedClassPathEntry* ent =
1229 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1230 if (!Universe::is_module_initialized()) {
1231 assert(ent != NULL && ent->is_modules_image(),
1232 "Loading non-bootstrap classes before the module system is initialized");
1233 assert(class_loader.is_null(), "sanity");
1234 return true;
1235 }
1236 // Get the pkg_entry from the classloader
1237 TempNewSymbol pkg_name = NULL;
1238 PackageEntry* pkg_entry = NULL;
1239 ModuleEntry* mod_entry = NULL;
1240 const char* pkg_string = NULL;
1241 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1242 if (pkg_name != NULL) {
1243 pkg_string = pkg_name->as_C_string();
1244 if (loader_data != NULL) {
1245 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1246 }
1247 if (pkg_entry != NULL) {
1248 mod_entry = pkg_entry->module();
1249 }
1250 }
1251
1252 // If the archived class is from a module that has been patched at runtime,
1253 // the class cannot be loaded from the archive.
1254 if (mod_entry != NULL && mod_entry->is_patched()) {
1255 return false;
1256 }
1257
1258 if (class_loader.is_null()) {
1259 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1260 // The NULL classloader can load archived class originated from the
1261 // "modules" jimage and the -Xbootclasspath/a. For class from the
1262 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1263 // by the NULL classloader.
1264 if (mod_entry != NULL) {
1265 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1266 // ModuleEntry's location agrees with the archived class' origination.
1267 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1268 return true; // Module class from the "module" jimage
1269 }
1270 }
1271
1272 // If the archived class is not from the "module" jimage, the class can be
1273 // loaded by the NULL classloader if
1274 //
1275 // 1. the class is from the unamed package
1276 // 2. or, the class is not from a module defined in the NULL classloader
1277 // 3. or, the class is from an unamed module
1278 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1279 // the class is from the -Xbootclasspath/a
1280 if (pkg_string == NULL ||
1281 pkg_entry == NULL ||
1282 pkg_entry->in_unnamed_module()) {
1283 assert(mod_entry == NULL ||
1284 mod_entry == loader_data->unnamed_module(),
1285 "the unnamed module is not defined in the classloader");
1286 return true;
1287 }
1288 }
1289 return false;
1290 } else {
1291 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1292 ik, class_loader, pkg_string, pkg_name,
1293 pkg_entry, mod_entry, CHECK_(false));
1294 return res;
1295 }
1296 }
1297
1298 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1299 Handle class_loader,
1300 Handle protection_domain, TRAPS) {
1301
1302 if (ik != NULL) {
1303 Symbol* class_name = ik->name();
1304
1305 bool visible = is_shared_class_visible(
1306 class_name, ik, class_loader, CHECK_NULL);
1307 if (!visible) {
1308 return NULL;
1309 }
1310
1311 // Resolve the superclass and interfaces. They must be the same
1312 // as in dump time, because the layout of <ik> depends on
1313 // the specific layout of ik->super() and ik->local_interfaces().
1314 //
1315 // If unexpected superclass or interfaces are found, we cannot
1316 // load <ik> from the shared archive.
1317
1318 if (ik->super() != NULL) {
1319 Symbol* cn = ik->super()->name();
1320 Klass *s = resolve_super_or_fail(class_name, cn,
1321 class_loader, protection_domain, true, CHECK_NULL);
1322 if (s != ik->super()) {
1323 // The dynamically resolved super class is not the same as the one we used during dump time,
1324 // so we cannot use ik.
1325 return NULL;
1326 } else {
1327 assert(s->is_shared(), "must be");
1328 }
1329 }
1330
1331 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1332 int num_interfaces = interfaces->length();
1333 for (int index = 0; index < num_interfaces; index++) {
1334 InstanceKlass* k = interfaces->at(index);
1335 Symbol* name = k->name();
1336 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1337 if (k != i) {
1338 // The dynamically resolved interface class is not the same as the one we used during dump time,
1339 // so we cannot use ik.
1340 return NULL;
1341 } else {
1342 assert(i->is_shared(), "must be");
1343 }
1344 }
1345
1346 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1347 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1348 if (new_ik != NULL) {
1349 // The class is changed by CFLH. Return the new class. The shared class is
1350 // not used.
1351 return new_ik;
1352 }
1353
1354 // Adjust methods to recover missing data. They need addresses for
1355 // interpreter entry points and their default native method address
1356 // must be reset.
1357
1358 // Updating methods must be done under a lock so multiple
1359 // threads don't update these in parallel
1360 //
1361 // Shared classes are all currently loaded by either the bootstrap or
1362 // internal parallel class loaders, so this will never cause a deadlock
1363 // on a custom class loader lock.
1364
1365 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1366 {
1367 HandleMark hm(THREAD);
1368 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1369 check_loader_lock_contention(lockObject, THREAD);
1370 ObjectLocker ol(lockObject, THREAD, true);
1371 // prohibited package check assumes all classes loaded from archive call
1372 // restore_unshareable_info which calls ik->set_package()
1373 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1374 }
1375
1376 ik->print_class_load_logging(loader_data, NULL, NULL);
1377
1378 // For boot loader, ensure that GetSystemPackage knows that a class in this
1379 // package was loaded.
1380 if (class_loader.is_null()) {
1381 int path_index = ik->shared_classpath_index();
1382 ResourceMark rm;
1383 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1384 }
1385
1386 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1387 // Only dump the classes that can be stored into CDS archive
1388 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1389 ResourceMark rm(THREAD);
1390 classlist_file->print_cr("%s", ik->name()->as_C_string());
1391 classlist_file->flush();
1392 }
1393 }
1394
1395 // notify a class loaded from shared object
1396 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1397
1398 ik->set_has_passed_fingerprint_check(false);
1399 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1400 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1401 uint64_t cds_fp = ik->get_stored_fingerprint();
1402 if (aot_fp != 0 && aot_fp == cds_fp) {
1403 // This class matches with a class saved in an AOT library
1404 ik->set_has_passed_fingerprint_check(true);
1405 } else {
1406 ResourceMark rm;
1407 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1408 }
1409 }
1410 }
1411 return ik;
1412 }
1413
1414 void SystemDictionary::clear_invoke_method_table() {
1415 SymbolPropertyEntry* spe = NULL;
1416 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1417 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1418 while (p != NULL) {
1419 spe = p;
1420 p = p->next();
1421 _invoke_method_table->free_entry(spe);
1422 }
1423 }
1424 }
1425 #endif // INCLUDE_CDS
1426
1427 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1428
1429 if (class_loader.is_null()) {
1430 ResourceMark rm;
1431 PackageEntry* pkg_entry = NULL;
1432 bool search_only_bootloader_append = false;
1433 ClassLoaderData *loader_data = class_loader_data(class_loader);
1434
1435 // Find the package in the boot loader's package entry table.
1436 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1437 if (pkg_name != NULL) {
1438 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1439 }
1440
1441 // Prior to attempting to load the class, enforce the boot loader's
1442 // visibility boundaries.
1443 if (!Universe::is_module_initialized()) {
1444 // During bootstrapping, prior to module initialization, any
1445 // class attempting to be loaded must be checked against the
1446 // java.base packages in the boot loader's PackageEntryTable.
1447 // No class outside of java.base is allowed to be loaded during
1448 // this bootstrapping window.
1449 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1450 // Class is either in the unnamed package or in
1451 // a named package within the unnamed module. Either
1452 // case is outside of java.base, do not attempt to
1453 // load the class post java.base definition. If
1454 // java.base has not been defined, let the class load
1455 // and its package will be checked later by
1456 // ModuleEntryTable::verify_javabase_packages.
1457 if (ModuleEntryTable::javabase_defined()) {
1458 return NULL;
1459 }
1460 } else {
1461 // Check that the class' package is defined within java.base.
1462 ModuleEntry* mod_entry = pkg_entry->module();
1463 Symbol* mod_entry_name = mod_entry->name();
1464 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1465 return NULL;
1466 }
1467 }
1468 } else {
1469 // After the module system has been initialized, check if the class'
1470 // package is in a module defined to the boot loader.
1471 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1472 // Class is either in the unnamed package, in a named package
1473 // within a module not defined to the boot loader or in a
1474 // a named package within the unnamed module. In all cases,
1475 // limit visibility to search for the class only in the boot
1476 // loader's append path.
1477 search_only_bootloader_append = true;
1478 }
1479 }
1480
1481 // Prior to bootstrapping's module initialization, never load a class outside
1482 // of the boot loader's module path
1483 assert(Universe::is_module_initialized() ||
1484 !search_only_bootloader_append,
1485 "Attempt to load a class outside of boot loader's module path");
1486
1487 // Search the shared system dictionary for classes preloaded into the
1488 // shared spaces.
1489 InstanceKlass* k = NULL;
1490 {
1491 #if INCLUDE_CDS
1492 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1493 k = load_shared_class(class_name, class_loader, THREAD);
1494 #endif
1495 }
1496
1497 if (k == NULL) {
1498 // Use VM class loader
1499 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1500 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1501 }
1502
1503 // find_or_define_instance_class may return a different InstanceKlass
1504 if (k != NULL) {
1505 InstanceKlass* defined_k =
1506 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1507 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1508 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1509 assert(defined_k != NULL, "Should have a klass if there's no exception");
1510 loader_data->add_to_deallocate_list(k);
1511 k = defined_k;
1512 } else if (HAS_PENDING_EXCEPTION) {
1513 loader_data->add_to_deallocate_list(k);
1514 return NULL;
1515 }
1516 }
1517 return k;
1518 } else {
1519 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1520 ResourceMark rm(THREAD);
1521
1522 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1523 JavaThread* jt = (JavaThread*) THREAD;
1524
1525 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1526 ClassLoader::perf_app_classload_selftime(),
1527 ClassLoader::perf_app_classload_count(),
1528 jt->get_thread_stat()->perf_recursion_counts_addr(),
1529 jt->get_thread_stat()->perf_timers_addr(),
1530 PerfClassTraceTime::CLASS_LOAD);
1531
1532 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1533 // Translate to external class name format, i.e., convert '/' chars to '.'
1534 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1535
1536 JavaValue result(T_OBJECT);
1537
1538 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1539
1540 // Call public unsynchronized loadClass(String) directly for all class loaders.
1541 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1542 // acquire a class-name based lock rather than the class loader object lock.
1543 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1544 JavaCalls::call_virtual(&result,
1545 class_loader,
1546 spec_klass,
1547 vmSymbols::loadClass_name(),
1548 vmSymbols::string_class_signature(),
1549 string,
1550 CHECK_NULL);
1551
1552 assert(result.get_type() == T_OBJECT, "just checking");
1553 oop obj = (oop) result.get_jobject();
1554
1555 // Primitive classes return null since forName() can not be
1556 // used to obtain any of the Class objects representing primitives or void
1557 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1558 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1559 // For user defined Java class loaders, check that the name returned is
1560 // the same as that requested. This check is done for the bootstrap
1561 // loader when parsing the class file.
1562 if (class_name == k->name()) {
1563 return k;
1564 }
1565 }
1566 // Class is not found or has the wrong name, return NULL
1567 return NULL;
1568 }
1569 }
1570
1571 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1572 EventClassDefine event;
1573 if (event.should_commit()) {
1574 event.set_definedClass(k);
1575 event.set_definingClassLoader(def_cld);
1576 event.commit();
1577 }
1578 }
1579
1580 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1581
1582 HandleMark hm(THREAD);
1583 ClassLoaderData* loader_data = k->class_loader_data();
1584 Handle class_loader_h(THREAD, loader_data->class_loader());
1585
1586 // for bootstrap and other parallel classloaders don't acquire lock,
1587 // use placeholder token
1588 // If a parallelCapable class loader calls define_instance_class instead of
1589 // find_or_define_instance_class to get here, we have a timing
1590 // hole with systemDictionary updates and check_constraints
1591 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1592 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1593 compute_loader_lock_object(class_loader_h, THREAD)),
1594 "define called without lock");
1595 }
1596
1597 // Check class-loading constraints. Throw exception if violation is detected.
1598 // Grabs and releases SystemDictionary_lock
1599 // The check_constraints/find_class call and update_dictionary sequence
1600 // must be "atomic" for a specific class/classloader pair so we never
1601 // define two different instanceKlasses for that class/classloader pair.
1602 // Existing classloaders will call define_instance_class with the
1603 // classloader lock held
1604 // Parallel classloaders will call find_or_define_instance_class
1605 // which will require a token to perform the define class
1606 Symbol* name_h = k->name();
1607 Dictionary* dictionary = loader_data->dictionary();
1608 unsigned int d_hash = dictionary->compute_hash(name_h);
1609 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1610
1611 // Register class just loaded with class loader (placed in Vector)
1612 // Note we do this before updating the dictionary, as this can
1613 // fail with an OutOfMemoryError (if it does, we will *not* put this
1614 // class in the dictionary and will not update the class hierarchy).
1615 // JVMTI FollowReferences needs to find the classes this way.
1616 if (k->class_loader() != NULL) {
1617 methodHandle m(THREAD, Universe::loader_addClass_method());
1618 JavaValue result(T_VOID);
1619 JavaCallArguments args(class_loader_h);
1620 args.push_oop(Handle(THREAD, k->java_mirror()));
1621 JavaCalls::call(&result, m, &args, CHECK);
1622 }
1623
1624 // Add the new class. We need recompile lock during update of CHA.
1625 {
1626 unsigned int p_hash = placeholders()->compute_hash(name_h);
1627 int p_index = placeholders()->hash_to_index(p_hash);
1628
1629 MutexLocker mu_r(Compile_lock, THREAD);
1630
1631 // Add to class hierarchy, initialize vtables, and do possible
1632 // deoptimizations.
1633 add_to_hierarchy(k, CHECK); // No exception, but can block
1634
1635 // Add to systemDictionary - so other classes can see it.
1636 // Grabs and releases SystemDictionary_lock
1637 update_dictionary(d_hash, p_index, p_hash,
1638 k, class_loader_h, THREAD);
1639 }
1640 k->eager_initialize(THREAD);
1641
1642 // notify jvmti
1643 if (JvmtiExport::should_post_class_load()) {
1644 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1645 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1646
1647 }
1648 post_class_define_event(k, loader_data);
1649 }
1650
1651 // Support parallel classloading
1652 // All parallel class loaders, including bootstrap classloader
1653 // lock a placeholder entry for this class/class_loader pair
1654 // to allow parallel defines of different classes for this class loader
1655 // With AllowParallelDefine flag==true, in case they do not synchronize around
1656 // FindLoadedClass/DefineClass, calls, we check for parallel
1657 // loading for them, wait if a defineClass is in progress
1658 // and return the initial requestor's results
1659 // This flag does not apply to the bootstrap classloader.
1660 // With AllowParallelDefine flag==false, call through to define_instance_class
1661 // which will throw LinkageError: duplicate class definition.
1662 // False is the requested default.
1663 // For better performance, the class loaders should synchronize
1664 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1665 // potentially waste time reading and parsing the bytestream.
1666 // Note: VM callers should ensure consistency of k/class_name,class_loader
1667 // Be careful when modifying this code: once you have run
1668 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1669 // you need to find_and_remove it before returning.
1670 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1671 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1672 InstanceKlass* k, TRAPS) {
1673
1674 Symbol* name_h = k->name(); // passed in class_name may be null
1675 ClassLoaderData* loader_data = class_loader_data(class_loader);
1676 Dictionary* dictionary = loader_data->dictionary();
1677
1678 unsigned int d_hash = dictionary->compute_hash(name_h);
1679
1680 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1681 unsigned int p_hash = placeholders()->compute_hash(name_h);
1682 int p_index = placeholders()->hash_to_index(p_hash);
1683 PlaceholderEntry* probe;
1684
1685 {
1686 MutexLocker mu(SystemDictionary_lock, THREAD);
1687 // First check if class already defined
1688 if (is_parallelDefine(class_loader)) {
1689 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1690 if (check != NULL) {
1691 return check;
1692 }
1693 }
1694
1695 // Acquire define token for this class/classloader
1696 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1697 // Wait if another thread defining in parallel
1698 // All threads wait - even those that will throw duplicate class: otherwise
1699 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1700 // if other thread has not finished updating dictionary
1701 while (probe->definer() != NULL) {
1702 SystemDictionary_lock->wait();
1703 }
1704 // Only special cases allow parallel defines and can use other thread's results
1705 // Other cases fall through, and may run into duplicate defines
1706 // caught by finding an entry in the SystemDictionary
1707 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1708 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1709 SystemDictionary_lock->notify_all();
1710 #ifdef ASSERT
1711 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1712 assert(check != NULL, "definer missed recording success");
1713 #endif
1714 return probe->instance_klass();
1715 } else {
1716 // This thread will define the class (even if earlier thread tried and had an error)
1717 probe->set_definer(THREAD);
1718 }
1719 }
1720
1721 define_instance_class(k, THREAD);
1722
1723 Handle linkage_exception = Handle(); // null handle
1724
1725 // definer must notify any waiting threads
1726 {
1727 MutexLocker mu(SystemDictionary_lock, THREAD);
1728 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1729 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1730 if (probe != NULL) {
1731 if (HAS_PENDING_EXCEPTION) {
1732 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1733 CLEAR_PENDING_EXCEPTION;
1734 } else {
1735 probe->set_instance_klass(k);
1736 }
1737 probe->set_definer(NULL);
1738 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1739 SystemDictionary_lock->notify_all();
1740 }
1741 }
1742
1743 // Can't throw exception while holding lock due to rank ordering
1744 if (linkage_exception() != NULL) {
1745 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1746 }
1747
1748 return k;
1749 }
1750
1751 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1752 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1753 if (class_loader.is_null()) {
1754 return Handle(THREAD, _system_loader_lock_obj);
1755 } else {
1756 return class_loader;
1757 }
1758 }
1759
1760 // This method is added to check how often we have to wait to grab loader
1761 // lock. The results are being recorded in the performance counters defined in
1762 // ClassLoader::_sync_systemLoaderLockContentionRate and
1763 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1764 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1765 if (!UsePerfData) {
1766 return;
1767 }
1768
1769 assert(!loader_lock.is_null(), "NULL lock object");
1770
1771 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1772 == ObjectSynchronizer::owner_other) {
1773 // contention will likely happen, so increment the corresponding
1774 // contention counter.
1775 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1776 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1777 } else {
1778 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1779 }
1780 }
1781 }
1782
1783 // ----------------------------------------------------------------------------
1784 // Lookup
1785
1786 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1787 Symbol* class_name,
1788 Dictionary* dictionary) {
1789 assert_locked_or_safepoint(SystemDictionary_lock);
1790 int index = dictionary->hash_to_index(hash);
1791 return dictionary->find_class(index, hash, class_name);
1792 }
1793
1794
1795 // Basic find on classes in the midst of being loaded
1796 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1797 ClassLoaderData* loader_data) {
1798 assert_locked_or_safepoint(SystemDictionary_lock);
1799 unsigned int p_hash = placeholders()->compute_hash(class_name);
1800 int p_index = placeholders()->hash_to_index(p_hash);
1801 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1802 }
1803
1804
1805 // Used for assertions and verification only
1806 // Precalculating the hash and index is an optimization because there are many lookups
1807 // before adding the class.
1808 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1809 assert_locked_or_safepoint(SystemDictionary_lock);
1810 #ifndef ASSERT
1811 guarantee(VerifyBeforeGC ||
1812 VerifyDuringGC ||
1813 VerifyBeforeExit ||
1814 VerifyDuringStartup ||
1815 VerifyAfterGC, "too expensive");
1816 #endif
1817
1818 Dictionary* dictionary = loader_data->dictionary();
1819 unsigned int d_hash = dictionary->compute_hash(class_name);
1820 return find_class(d_hash, class_name, dictionary);
1821 }
1822
1823
1824 // ----------------------------------------------------------------------------
1825 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1826 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1827 // before a new class is used.
1828
1829 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1830 assert(k != NULL, "just checking");
1831 assert_locked_or_safepoint(Compile_lock);
1832
1833 // Link into hierachy. Make sure the vtables are initialized before linking into
1834 k->append_to_sibling_list(); // add to superklass/sibling list
1835 k->process_interfaces(THREAD); // handle all "implements" declarations
1836 k->set_init_state(InstanceKlass::loaded);
1837 // Now flush all code that depended on old class hierarchy.
1838 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1839 // Also, first reinitialize vtable because it may have gotten out of synch
1840 // while the new class wasn't connected to the class hierarchy.
1841 CodeCache::flush_dependents_on(k);
1842 }
1843
1844 // ----------------------------------------------------------------------------
1845 // GC support
1846
1847 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1848 // Note: anonymous classes are not in the SD.
1849 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1850 bool do_cleaning) {
1851
1852 bool unloading_occurred;
1853 {
1854 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1855
1856 #if INCLUDE_JFR
1857 // If unloading occurs, make sure time stamp is consistent.
1858 if (Jfr::is_enabled()) {
1859 InstanceKlass::set_class_unload_time(Ticks::now());
1860 }
1861 #endif
1862
1863 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1864 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1865 if (unloading_occurred) {
1866 ClassLoaderDataGraph::clean_module_and_package_info();
1867 #if INCLUDE_JFR
1868 if (Jfr::is_enabled()) {
1869 Jfr::on_unloading_classes();
1870 }
1871 #endif
1872 }
1873 }
1874
1875 // TODO: just return if !unloading_occurred.
1876 if (unloading_occurred) {
1877 {
1878 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
1879 // Check if there's work to do in the SymbolTable
1880 SymbolTable::do_check_concurrent_work();
1881 }
1882
1883 {
1884 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1885 constraints()->purge_loader_constraints();
1886 resolution_errors()->purge_resolution_errors();
1887 }
1888 }
1889
1890 {
1891 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1892 // Oops referenced by the protection domain cache table may get unreachable independently
1893 // of the class loader (eg. cached protection domain oops). So we need to
1894 // explicitly unlink them here.
1895 _pd_cache_table->unlink();
1896 }
1897
1898 if (do_cleaning) {
1899 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1900 ResolvedMethodTable::trigger_cleanup();
1901 }
1902
1903 return unloading_occurred;
1904 }
1905
1906 void SystemDictionary::oops_do(OopClosure* f) {
1907 f->do_oop(&_java_system_loader);
1908 f->do_oop(&_java_platform_loader);
1909 f->do_oop(&_system_loader_lock_obj);
1910 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1911
1912 // Visit extra methods
1913 invoke_method_table()->oops_do(f);
1914 }
1915
1916 // CDS: scan and relocate all classes in the system dictionary.
1917 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1918 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1919 }
1920
1921 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1922 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1923 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1924 it->push(well_known_klass_addr((WKID)id));
1925 }
1926 }
1927
1928 void SystemDictionary::methods_do(void f(Method*)) {
1929 // Walk methods in loaded classes
1930 ClassLoaderDataGraph::methods_do(f);
1931 // Walk method handle intrinsics
1932 invoke_method_table()->methods_do(f);
1933 }
1934
1935 class RemoveClassesClosure : public CLDClosure {
1936 public:
1937 void do_cld(ClassLoaderData* cld) {
1938 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1939 cld->dictionary()->remove_classes_in_error_state();
1940 }
1941 }
1942 };
1943
1944 void SystemDictionary::remove_classes_in_error_state() {
1945 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1946 RemoveClassesClosure rcc;
1947 ClassLoaderDataGraph::cld_do(&rcc);
1948 }
1949
1950 // ----------------------------------------------------------------------------
1951 // Initialization
1952
1953 void SystemDictionary::initialize(TRAPS) {
1954 // Allocate arrays
1955 _placeholders = new PlaceholderTable(_placeholder_table_size);
1956 _number_of_modifications = 0;
1957 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1958 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1959 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1960 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1961
1962 // Allocate private object used as system class loader lock
1963 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1964 // Initialize basic classes
1965 resolve_preloaded_classes(CHECK);
1966 }
1967
1968 // Compact table of directions on the initialization of klasses:
1969 static const short wk_init_info[] = {
1970 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1971 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1972 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1973 | (int)SystemDictionary::option ),
1974 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1975 #undef WK_KLASS_INIT_INFO
1976 0
1977 };
1978
1979 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) {
1980 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1981 int info = wk_init_info[id - FIRST_WKID];
1982 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1983 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1984 InstanceKlass** klassp = &_well_known_klasses[id];
1985
1986 bool must_load;
1987 #if INCLUDE_JVMCI
1988 if (EnableJVMCI) {
1989 // If JVMCI is enabled we require its classes to be found.
1990 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1991 } else
1992 #endif
1993 {
1994 must_load = (init_opt < SystemDictionary::Opt);
1995 }
1996
1997 if ((*klassp) == NULL) {
1998 Klass* k;
1999 if (must_load) {
2000 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2001 } else {
2002 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2003 }
2004 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2005 }
2006 return ((*klassp) != NULL);
2007 }
2008
2009 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2010 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2011 for (int id = (int)start_id; id < (int)limit_id; id++) {
2012 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2013 int info = wk_init_info[id - FIRST_WKID];
2014 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2015 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2016
2017 resolve_wk_klass((WKID)id, opt, CHECK);
2018 }
2019
2020 // move the starting value forward to the limit:
2021 start_id = limit_id;
2022 }
2023
2024 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
2025 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2026
2027 // Create the ModuleEntry for java.base. This call needs to be done here,
2028 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2029 ClassLoader::classLoader_init2(CHECK);
2030
2031 // Preload commonly used klasses
2032 WKID scan = FIRST_WKID;
2033 // first do Object, then String, Class
2034 #if INCLUDE_CDS
2035 if (UseSharedSpaces) {
2036 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2037 // Initialize the constant pool for the Object_class
2038 Object_klass()->constants()->restore_unshareable_info(CHECK);
2039 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2040 } else
2041 #endif
2042 {
2043 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2044 }
2045
2046 // Calculate offsets for String and Class classes since they are loaded and
2047 // can be used after this point.
2048 java_lang_String::compute_offsets();
2049 java_lang_Class::compute_offsets();
2050
2051 // Fixup mirrors for classes loaded before java.lang.Class.
2052 // These calls iterate over the objects currently in the perm gen
2053 // so calling them at this point is matters (not before when there
2054 // are fewer objects and not later after there are more objects
2055 // in the perm gen.
2056 Universe::initialize_basic_type_mirrors(CHECK);
2057 Universe::fixup_mirrors(CHECK);
2058
2059 // do a bunch more:
2060 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2061
2062 // Preload ref klasses and set reference types
2063 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2064 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2065
2066 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2067 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2068 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2069 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2070 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2071
2072 // JSR 292 classes
2073 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2074 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2075 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2076 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2077 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2078
2079 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2080 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2081 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2082 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2083 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2084 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2085 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2086 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2087 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2088 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2089
2090 { // Compute whether we should use checkPackageAccess or NOT
2091 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2092 _has_checkPackageAccess = (method != NULL);
2093 }
2094 }
2095
2096 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2097 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2098 BasicType SystemDictionary::box_klass_type(Klass* k) {
2099 assert(k != NULL, "");
2100 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2101 if (_box_klasses[i] == k)
2102 return (BasicType)i;
2103 }
2104 return T_OBJECT;
2105 }
2106
2107 // Constraints on class loaders. The details of the algorithm can be
2108 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2109 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2110 // that the dictionary needs to maintain a set of contraints that
2111 // must be satisfied by all classes in the dictionary.
2112 // if defining is true, then LinkageError if already in dictionary
2113 // if initiating loader, then ok if InstanceKlass matches existing entry
2114
2115 void SystemDictionary::check_constraints(unsigned int d_hash,
2116 InstanceKlass* k,
2117 Handle class_loader,
2118 bool defining,
2119 TRAPS) {
2120 ResourceMark rm(THREAD);
2121 stringStream ss;
2122 bool throwException = false;
2123
2124 {
2125 Symbol *name = k->name();
2126 ClassLoaderData *loader_data = class_loader_data(class_loader);
2127
2128 MutexLocker mu(SystemDictionary_lock, THREAD);
2129
2130 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2131 if (check != NULL) {
2132 // If different InstanceKlass - duplicate class definition,
2133 // else - ok, class loaded by a different thread in parallel.
2134 // We should only have found it if it was done loading and ok to use.
2135 // The dictionary only holds instance classes, placeholders
2136 // also hold array classes.
2137
2138 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2139 if ((defining == true) || (k != check)) {
2140 throwException = true;
2141 ss.print("loader %s", loader_data->loader_name_and_id());
2142 ss.print(" attempted duplicate %s definition for %s. (%s)",
2143 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2144 } else {
2145 return;
2146 }
2147 }
2148
2149 #ifdef ASSERT
2150 Symbol* ph_check = find_placeholder(name, loader_data);
2151 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2152 #endif
2153
2154 if (throwException == false) {
2155 if (constraints()->check_or_update(k, class_loader, name) == false) {
2156 throwException = true;
2157 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2158 ss.print(" wants to load %s %s.",
2159 k->external_kind(), k->external_name());
2160 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2161 if (existing_klass->class_loader() != class_loader()) {
2162 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2163 existing_klass->external_kind(),
2164 existing_klass->class_loader_data()->loader_name_and_id(),
2165 existing_klass->class_in_module_of_loader(false, true));
2166 } else {
2167 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2168 }
2169 }
2170 }
2171 }
2172
2173 // Throw error now if needed (cannot throw while holding
2174 // SystemDictionary_lock because of rank ordering)
2175 if (throwException == true) {
2176 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2177 }
2178 }
2179
2180 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2181 // have been called.
2182 void SystemDictionary::update_dictionary(unsigned int d_hash,
2183 int p_index, unsigned int p_hash,
2184 InstanceKlass* k,
2185 Handle class_loader,
2186 TRAPS) {
2187 // Compile_lock prevents systemDictionary updates during compilations
2188 assert_locked_or_safepoint(Compile_lock);
2189 Symbol* name = k->name();
2190 ClassLoaderData *loader_data = class_loader_data(class_loader);
2191
2192 {
2193 MutexLocker mu1(SystemDictionary_lock, THREAD);
2194
2195 // See whether biased locking is enabled and if so set it for this
2196 // klass.
2197 // Note that this must be done past the last potential blocking
2198 // point / safepoint. We enable biased locking lazily using a
2199 // VM_Operation to iterate the SystemDictionary and installing the
2200 // biasable mark word into each InstanceKlass's prototype header.
2201 // To avoid race conditions where we accidentally miss enabling the
2202 // optimization for one class in the process of being added to the
2203 // dictionary, we must not safepoint after the test of
2204 // BiasedLocking::enabled().
2205 if (UseBiasedLocking && BiasedLocking::enabled()) {
2206 // Set biased locking bit for all loaded classes; it will be
2207 // cleared if revocation occurs too often for this type
2208 // NOTE that we must only do this when the class is initally
2209 // defined, not each time it is referenced from a new class loader
2210 if (oopDesc::equals(k->class_loader(), class_loader())) {
2211 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2212 }
2213 }
2214
2215 // Make a new dictionary entry.
2216 Dictionary* dictionary = loader_data->dictionary();
2217 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2218 if (sd_check == NULL) {
2219 dictionary->add_klass(d_hash, name, k);
2220 notice_modification();
2221 }
2222 #ifdef ASSERT
2223 sd_check = find_class(d_hash, name, dictionary);
2224 assert (sd_check != NULL, "should have entry in dictionary");
2225 // Note: there may be a placeholder entry: for circularity testing
2226 // or for parallel defines
2227 #endif
2228 SystemDictionary_lock->notify_all();
2229 }
2230 }
2231
2232
2233 // Try to find a class name using the loader constraints. The
2234 // loader constraints might know about a class that isn't fully loaded
2235 // yet and these will be ignored.
2236 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2237 Symbol* class_name, Handle class_loader, TRAPS) {
2238
2239 // First see if it has been loaded directly.
2240 // Force the protection domain to be null. (This removes protection checks.)
2241 Handle no_protection_domain;
2242 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2243 no_protection_domain, CHECK_NULL);
2244 if (klass != NULL)
2245 return klass;
2246
2247 // Now look to see if it has been loaded elsewhere, and is subject to
2248 // a loader constraint that would require this loader to return the
2249 // klass that is already loaded.
2250 if (FieldType::is_array(class_name)) {
2251 // For array classes, their Klass*s are not kept in the
2252 // constraint table. The element Klass*s are.
2253 FieldArrayInfo fd;
2254 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2255 if (t != T_OBJECT) {
2256 klass = Universe::typeArrayKlassObj(t);
2257 } else {
2258 MutexLocker mu(SystemDictionary_lock, THREAD);
2259 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2260 }
2261 // If element class already loaded, allocate array klass
2262 if (klass != NULL) {
2263 klass = klass->array_klass_or_null(fd.dimension());
2264 }
2265 } else {
2266 MutexLocker mu(SystemDictionary_lock, THREAD);
2267 // Non-array classes are easy: simply check the constraint table.
2268 klass = constraints()->find_constrained_klass(class_name, class_loader);
2269 }
2270
2271 return klass;
2272 }
2273
2274
2275 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2276 Handle class_loader1,
2277 Handle class_loader2,
2278 Thread* THREAD) {
2279 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2280 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2281
2282 Symbol* constraint_name = NULL;
2283 // Needs to be in same scope as constraint_name in case a Symbol is created and
2284 // assigned to constraint_name.
2285 FieldArrayInfo fd;
2286 if (!FieldType::is_array(class_name)) {
2287 constraint_name = class_name;
2288 } else {
2289 // For array classes, their Klass*s are not kept in the
2290 // constraint table. The element classes are.
2291 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2292 // primitive types always pass
2293 if (t != T_OBJECT) {
2294 return true;
2295 } else {
2296 constraint_name = fd.object_key();
2297 }
2298 }
2299
2300 Dictionary* dictionary1 = loader_data1->dictionary();
2301 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2302
2303 Dictionary* dictionary2 = loader_data2->dictionary();
2304 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2305
2306 {
2307 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2308 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2309 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2310 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2311 klass2, class_loader2);
2312 }
2313 }
2314
2315 // Add entry to resolution error table to record the error when the first
2316 // attempt to resolve a reference to a class has failed.
2317 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2318 Symbol* error, Symbol* message) {
2319 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2320 int index = resolution_errors()->hash_to_index(hash);
2321 {
2322 MutexLocker ml(SystemDictionary_lock, Thread::current());
2323 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2324 }
2325 }
2326
2327 // Delete a resolution error for RedefineClasses for a constant pool is going away
2328 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2329 resolution_errors()->delete_entry(pool);
2330 }
2331
2332 // Lookup resolution error table. Returns error if found, otherwise NULL.
2333 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2334 Symbol** message) {
2335 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2336 int index = resolution_errors()->hash_to_index(hash);
2337 {
2338 MutexLocker ml(SystemDictionary_lock, Thread::current());
2339 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2340 if (entry != NULL) {
2341 *message = entry->message();
2342 return entry->error();
2343 } else {
2344 return NULL;
2345 }
2346 }
2347 }
2348
2349
2350 // Signature constraints ensure that callers and callees agree about
2351 // the meaning of type names in their signatures. This routine is the
2352 // intake for constraints. It collects them from several places:
2353 //
2354 // * LinkResolver::resolve_method (if check_access is true) requires
2355 // that the resolving class (the caller) and the defining class of
2356 // the resolved method (the callee) agree on each type in the
2357 // method's signature.
2358 //
2359 // * LinkResolver::resolve_interface_method performs exactly the same
2360 // checks.
2361 //
2362 // * LinkResolver::resolve_field requires that the constant pool
2363 // attempting to link to a field agree with the field's defining
2364 // class about the type of the field signature.
2365 //
2366 // * klassVtable::initialize_vtable requires that, when a class
2367 // overrides a vtable entry allocated by a superclass, that the
2368 // overriding method (i.e., the callee) agree with the superclass
2369 // on each type in the method's signature.
2370 //
2371 // * klassItable::initialize_itable requires that, when a class fills
2372 // in its itables, for each non-abstract method installed in an
2373 // itable, the method (i.e., the callee) agree with the interface
2374 // on each type in the method's signature.
2375 //
2376 // All those methods have a boolean (check_access, checkconstraints)
2377 // which turns off the checks. This is used from specialized contexts
2378 // such as bootstrapping, dumping, and debugging.
2379 //
2380 // No direct constraint is placed between the class and its
2381 // supertypes. Constraints are only placed along linked relations
2382 // between callers and callees. When a method overrides or implements
2383 // an abstract method in a supertype (superclass or interface), the
2384 // constraints are placed as if the supertype were the caller to the
2385 // overriding method. (This works well, since callers to the
2386 // supertype have already established agreement between themselves and
2387 // the supertype.) As a result of all this, a class can disagree with
2388 // its supertype about the meaning of a type name, as long as that
2389 // class neither calls a relevant method of the supertype, nor is
2390 // called (perhaps via an override) from the supertype.
2391 //
2392 //
2393 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2394 //
2395 // Make sure all class components (including arrays) in the given
2396 // signature will be resolved to the same class in both loaders.
2397 // Returns the name of the type that failed a loader constraint check, or
2398 // NULL if no constraint failed. No exception except OOME is thrown.
2399 // Arrays are not added to the loader constraint table, their elements are.
2400 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2401 Handle loader1, Handle loader2,
2402 bool is_method, TRAPS) {
2403 // Nothing to do if loaders are the same.
2404 if (oopDesc::equals(loader1(), loader2())) {
2405 return NULL;
2406 }
2407
2408 SignatureStream sig_strm(signature, is_method);
2409 while (!sig_strm.is_done()) {
2410 if (sig_strm.is_object()) {
2411 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2412 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2413 return sig;
2414 }
2415 }
2416 sig_strm.next();
2417 }
2418 return NULL;
2419 }
2420
2421
2422 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2423 Symbol* signature,
2424 TRAPS) {
2425 methodHandle empty;
2426 assert(MethodHandles::is_signature_polymorphic(iid) &&
2427 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2428 iid != vmIntrinsics::_invokeGeneric,
2429 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2430
2431 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2432 int index = invoke_method_table()->hash_to_index(hash);
2433 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2434 methodHandle m;
2435 if (spe == NULL || spe->method() == NULL) {
2436 spe = NULL;
2437 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2438 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2439 if (!Arguments::is_interpreter_only()) {
2440 // Generate a compiled form of the MH intrinsic.
2441 AdapterHandlerLibrary::create_native_wrapper(m);
2442 // Check if have the compiled code.
2443 if (!m->has_compiled_code()) {
2444 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2445 "Out of space in CodeCache for method handle intrinsic", empty);
2446 }
2447 }
2448 // Now grab the lock. We might have to throw away the new method,
2449 // if a racing thread has managed to install one at the same time.
2450 {
2451 MutexLocker ml(SystemDictionary_lock, THREAD);
2452 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2453 if (spe == NULL)
2454 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2455 if (spe->method() == NULL)
2456 spe->set_method(m());
2457 }
2458 }
2459
2460 assert(spe != NULL && spe->method() != NULL, "");
2461 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2462 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2463 "MH intrinsic invariant");
2464 return spe->method();
2465 }
2466
2467 // Helper for unpacking the return value from linkMethod and linkCallSite.
2468 static methodHandle unpack_method_and_appendix(Handle mname,
2469 Klass* accessing_klass,
2470 objArrayHandle appendix_box,
2471 Handle* appendix_result,
2472 TRAPS) {
2473 methodHandle empty;
2474 if (mname.not_null()) {
2475 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2476 if (m != NULL) {
2477 oop appendix = appendix_box->obj_at(0);
2478 if (TraceMethodHandles) {
2479 #ifndef PRODUCT
2480 ttyLocker ttyl;
2481 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2482 m->print();
2483 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2484 tty->cr();
2485 #endif //PRODUCT
2486 }
2487 (*appendix_result) = Handle(THREAD, appendix);
2488 // the target is stored in the cpCache and if a reference to this
2489 // MemberName is dropped we need a way to make sure the
2490 // class_loader containing this method is kept alive.
2491 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2492 this_key->record_dependency(m->method_holder());
2493 return methodHandle(THREAD, m);
2494 }
2495 }
2496 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2497 return empty;
2498 }
2499
2500 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2501 Symbol* name,
2502 Symbol* signature,
2503 Klass* accessing_klass,
2504 Handle *appendix_result,
2505 Handle *method_type_result,
2506 TRAPS) {
2507 methodHandle empty;
2508 assert(THREAD->can_call_java() ,"");
2509 Handle method_type =
2510 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2511
2512 int ref_kind = JVM_REF_invokeVirtual;
2513 oop name_oop = StringTable::intern(name, CHECK_(empty));
2514 Handle name_str (THREAD, name_oop);
2515 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2516 assert(appendix_box->obj_at(0) == NULL, "");
2517
2518 // This should not happen. JDK code should take care of that.
2519 if (accessing_klass == NULL || method_type.is_null()) {
2520 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2521 }
2522
2523 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2524 JavaCallArguments args;
2525 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2526 args.push_int(ref_kind);
2527 args.push_oop(Handle(THREAD, klass->java_mirror()));
2528 args.push_oop(name_str);
2529 args.push_oop(method_type);
2530 args.push_oop(appendix_box);
2531 JavaValue result(T_OBJECT);
2532 JavaCalls::call_static(&result,
2533 SystemDictionary::MethodHandleNatives_klass(),
2534 vmSymbols::linkMethod_name(),
2535 vmSymbols::linkMethod_signature(),
2536 &args, CHECK_(empty));
2537 Handle mname(THREAD, (oop) result.get_jobject());
2538 (*method_type_result) = method_type;
2539 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2540 }
2541
2542 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2543 // We must ensure that all class loaders everywhere will reach this class, for any client.
2544 // This is a safe bet for public classes in java.lang, such as Object and String.
2545 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2546 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2547 static bool is_always_visible_class(oop mirror) {
2548 Klass* klass = java_lang_Class::as_Klass(mirror);
2549 if (klass->is_objArray_klass()) {
2550 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2551 }
2552 if (klass->is_typeArray_klass()) {
2553 return true; // primitive array
2554 }
2555 assert(klass->is_instance_klass(), "%s", klass->external_name());
2556 return klass->is_public() &&
2557 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2558 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2559 }
2560
2561
2562 // Return the Java mirror (java.lang.Class instance) for a single-character
2563 // descriptor. This result, when available, is the same as produced by the
2564 // heavier API point of the same name that takes a Symbol.
2565 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2566 return java_lang_Class::primitive_mirror(char2type(signature_char));
2567 }
2568
2569 // Find or construct the Java mirror (java.lang.Class instance) for a
2570 // for the given field type signature, as interpreted relative to the
2571 // given class loader. Handles primitives, void, references, arrays,
2572 // and all other reflectable types, except method types.
2573 // N.B. Code in reflection should use this entry point.
2574 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2575 Klass* accessing_klass,
2576 Handle class_loader,
2577 Handle protection_domain,
2578 SignatureStream::FailureMode failure_mode,
2579 TRAPS) {
2580 Handle empty;
2581
2582 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2583 "one or the other, or perhaps neither");
2584
2585 Symbol* type = signature;
2586
2587 // What we have here must be a valid field descriptor,
2588 // and all valid field descriptors are supported.
2589 // Produce the same java.lang.Class that reflection reports.
2590 if (type->utf8_length() == 1) {
2591
2592 // It's a primitive. (Void has a primitive mirror too.)
2593 char ch = (char) type->byte_at(0);
2594 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2595 return Handle(THREAD, find_java_mirror_for_type(ch));
2596
2597 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2598
2599 // It's a reference type.
2600 if (accessing_klass != NULL) {
2601 class_loader = Handle(THREAD, accessing_klass->class_loader());
2602 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2603 }
2604 Klass* constant_type_klass;
2605 if (failure_mode == SignatureStream::ReturnNull) {
2606 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2607 CHECK_(empty));
2608 } else {
2609 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2610 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2611 throw_error, CHECK_(empty));
2612 }
2613 if (constant_type_klass == NULL) {
2614 return Handle(); // report failure this way
2615 }
2616 Handle mirror(THREAD, constant_type_klass->java_mirror());
2617
2618 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2619 if (accessing_klass != NULL) {
2620 Klass* sel_klass = constant_type_klass;
2621 bool fold_type_to_class = true;
2622 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2623 fold_type_to_class, CHECK_(empty));
2624 }
2625
2626 return mirror;
2627
2628 }
2629
2630 // Fall through to an error.
2631 assert(false, "unsupported mirror syntax");
2632 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2633 }
2634
2635
2636 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2637 // signature, as interpreted relative to the given class loader.
2638 // Because of class loader constraints, all method handle usage must be
2639 // consistent with this loader.
2640 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2641 Klass* accessing_klass,
2642 TRAPS) {
2643 Handle empty;
2644 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2645 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2646 int index = invoke_method_table()->hash_to_index(hash);
2647 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2648 if (spe != NULL && spe->method_type() != NULL) {
2649 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2650 return Handle(THREAD, spe->method_type());
2651 } else if (!THREAD->can_call_java()) {
2652 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2653 return Handle(); // do not attempt from within compiler, unless it was cached
2654 }
2655
2656 Handle class_loader, protection_domain;
2657 if (accessing_klass != NULL) {
2658 class_loader = Handle(THREAD, accessing_klass->class_loader());
2659 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2660 }
2661 bool can_be_cached = true;
2662 int npts = ArgumentCount(signature).size();
2663 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2664 int arg = 0;
2665 Handle rt; // the return type from the signature
2666 ResourceMark rm(THREAD);
2667 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2668 oop mirror = NULL;
2669 if (can_be_cached) {
2670 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2671 mirror = ss.as_java_mirror(Handle(), Handle(),
2672 SignatureStream::ReturnNull, CHECK_(empty));
2673 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2674 // Fall back to accessing_klass context.
2675 can_be_cached = false;
2676 }
2677 }
2678 if (!can_be_cached) {
2679 // Resolve, throwing a real error if it doesn't work.
2680 mirror = ss.as_java_mirror(class_loader, protection_domain,
2681 SignatureStream::NCDFError, CHECK_(empty));
2682 }
2683 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2684 if (ss.at_return_type())
2685 rt = Handle(THREAD, mirror);
2686 else
2687 pts->obj_at_put(arg++, mirror);
2688
2689 // Check accessibility.
2690 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2691 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2692 mirror = NULL; // safety
2693 // Emulate ConstantPool::verify_constant_pool_resolve.
2694 bool fold_type_to_class = true;
2695 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2696 fold_type_to_class, CHECK_(empty));
2697 }
2698 }
2699 assert(arg == npts, "");
2700
2701 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2702 JavaCallArguments args(Handle(THREAD, rt()));
2703 args.push_oop(pts);
2704 JavaValue result(T_OBJECT);
2705 JavaCalls::call_static(&result,
2706 SystemDictionary::MethodHandleNatives_klass(),
2707 vmSymbols::findMethodHandleType_name(),
2708 vmSymbols::findMethodHandleType_signature(),
2709 &args, CHECK_(empty));
2710 Handle method_type(THREAD, (oop) result.get_jobject());
2711
2712 if (can_be_cached) {
2713 // We can cache this MethodType inside the JVM.
2714 MutexLocker ml(SystemDictionary_lock, THREAD);
2715 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2716 if (spe == NULL)
2717 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2718 if (spe->method_type() == NULL) {
2719 spe->set_method_type(method_type());
2720 }
2721 }
2722
2723 // report back to the caller with the MethodType
2724 return method_type;
2725 }
2726
2727 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2728 Klass* accessing_klass,
2729 TRAPS) {
2730 Handle empty;
2731 ResourceMark rm(THREAD);
2732 SignatureStream ss(signature, /*is_method=*/ false);
2733 if (!ss.is_done()) {
2734 Handle class_loader, protection_domain;
2735 if (accessing_klass != NULL) {
2736 class_loader = Handle(THREAD, accessing_klass->class_loader());
2737 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2738 }
2739 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2740 ss.next();
2741 if (ss.is_done()) {
2742 return Handle(THREAD, mirror);
2743 }
2744 }
2745 return empty;
2746 }
2747
2748 // Ask Java code to find or construct a method handle constant.
2749 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2750 int ref_kind, //e.g., JVM_REF_invokeVirtual
2751 Klass* callee,
2752 Symbol* name,
2753 Symbol* signature,
2754 TRAPS) {
2755 Handle empty;
2756 if (caller == NULL) {
2757 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2758 }
2759 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2760 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2761
2762 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2763 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2764 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2765 java_lang_invoke_MemberName::set_name (mname(), name_str());
2766 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2767 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2768
2769 if (ref_kind == JVM_REF_invokeVirtual &&
2770 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2771 // Skip resolution for public signature polymorphic methods such as
2772 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2773 // They require appendix argument which MemberName resolution doesn't handle.
2774 // There's special logic on JDK side to handle them
2775 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2776 } else {
2777 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2778 }
2779
2780 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2781 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2782
2783 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2784 JavaCallArguments args;
2785 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2786 args.push_int(ref_kind);
2787 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2788 args.push_oop(name_str);
2789 args.push_oop(type);
2790 JavaValue result(T_OBJECT);
2791 JavaCalls::call_static(&result,
2792 SystemDictionary::MethodHandleNatives_klass(),
2793 vmSymbols::linkMethodHandleConstant_name(),
2794 vmSymbols::linkMethodHandleConstant_signature(),
2795 &args, CHECK_(empty));
2796 return Handle(THREAD, (oop) result.get_jobject());
2797 }
2798
2799 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2800 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2801 int condy_index,
2802 Handle bootstrap_specifier,
2803 Symbol* name,
2804 Symbol* type,
2805 TRAPS) {
2806 Handle empty;
2807 Handle bsm, info;
2808 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2809 bsm = bootstrap_specifier;
2810 } else {
2811 assert(bootstrap_specifier->is_objArray(), "");
2812 objArrayOop args = (objArrayOop) bootstrap_specifier();
2813 assert(args->length() == 2, "");
2814 bsm = Handle(THREAD, args->obj_at(0));
2815 info = Handle(THREAD, args->obj_at(1));
2816 }
2817 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2818 "caller must supply a valid BSM");
2819
2820 // This should not happen. JDK code should take care of that.
2821 if (caller == NULL) {
2822 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2823 }
2824
2825 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2826
2827 // Resolve the constant type in the context of the caller class
2828 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2829 CHECK_(empty));
2830
2831 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2832 JavaCallArguments args;
2833 args.push_oop(Handle(THREAD, caller->java_mirror()));
2834 args.push_int(condy_index);
2835 args.push_oop(bsm);
2836 args.push_oop(constant_name);
2837 args.push_oop(type_mirror);
2838 args.push_oop(info);
2839 JavaValue result(T_OBJECT);
2840 JavaCalls::call_static(&result,
2841 SystemDictionary::MethodHandleNatives_klass(),
2842 vmSymbols::linkDynamicConstant_name(),
2843 vmSymbols::linkDynamicConstant_signature(),
2844 &args, CHECK_(empty));
2845
2846 return Handle(THREAD, (oop) result.get_jobject());
2847 }
2848
2849 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2850 // name and signature, as interpreted relative to the given class loader.
2851 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2852 int indy_index,
2853 Handle bootstrap_specifier,
2854 Symbol* name,
2855 Symbol* type,
2856 Handle *appendix_result,
2857 Handle *method_type_result,
2858 TRAPS) {
2859 methodHandle empty;
2860 Handle bsm, info;
2861 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2862 bsm = bootstrap_specifier;
2863 } else {
2864 objArrayOop args = (objArrayOop) bootstrap_specifier();
2865 assert(args->length() == 2, "");
2866 bsm = Handle(THREAD, args->obj_at(0));
2867 info = Handle(THREAD, args->obj_at(1));
2868 }
2869 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2870 "caller must supply a valid BSM");
2871
2872 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2873 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2874
2875 // This should not happen. JDK code should take care of that.
2876 if (caller == NULL || method_type.is_null()) {
2877 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2878 }
2879
2880 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2881 assert(appendix_box->obj_at(0) == NULL, "");
2882
2883 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2884 JavaCallArguments args;
2885 args.push_oop(Handle(THREAD, caller->java_mirror()));
2886 args.push_int(indy_index);
2887 args.push_oop(bsm);
2888 args.push_oop(method_name);
2889 args.push_oop(method_type);
2890 args.push_oop(info);
2891 args.push_oop(appendix_box);
2892 JavaValue result(T_OBJECT);
2893 JavaCalls::call_static(&result,
2894 SystemDictionary::MethodHandleNatives_klass(),
2895 vmSymbols::linkCallSite_name(),
2896 vmSymbols::linkCallSite_signature(),
2897 &args, CHECK_(empty));
2898 Handle mname(THREAD, (oop) result.get_jobject());
2899 (*method_type_result) = method_type;
2900 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2901 }
2902
2903 // Protection domain cache table handling
2904
2905 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2906 return _pd_cache_table->get(protection_domain);
2907 }
2908
2909 #if INCLUDE_CDS
2910 void SystemDictionary::reorder_dictionary_for_sharing() {
2911 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2912 }
2913 #endif
2914
2915 size_t SystemDictionary::count_bytes_for_buckets() {
2916 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2917 }
2918
2919 size_t SystemDictionary::count_bytes_for_table() {
2920 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2921 }
2922
2923 void SystemDictionary::copy_buckets(char* top, char* end) {
2924 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2925 }
2926
2927 void SystemDictionary::copy_table(char* top, char* end) {
2928 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2929 }
2930
2931 // ----------------------------------------------------------------------------
2932 void SystemDictionary::print_shared(outputStream *st) {
2933 shared_dictionary()->print_on(st);
2934 }
2935
2936 void SystemDictionary::print_on(outputStream *st) {
2937 if (shared_dictionary() != NULL) {
2938 st->print_cr("Shared Dictionary");
2939 shared_dictionary()->print_on(st);
2940 st->cr();
2941 }
2942
2943 GCMutexLocker mu(SystemDictionary_lock);
2944
2945 ClassLoaderDataGraph::print_dictionary(st);
2946
2947 // Placeholders
2948 placeholders()->print_on(st);
2949 st->cr();
2950
2951 // loader constraints - print under SD_lock
2952 constraints()->print_on(st);
2953 st->cr();
2954
2955 _pd_cache_table->print_on(st);
2956 st->cr();
2957 }
2958
2959 void SystemDictionary::verify() {
2960 guarantee(constraints() != NULL,
2961 "Verify of loader constraints failed");
2962 guarantee(placeholders()->number_of_entries() >= 0,
2963 "Verify of placeholders failed");
2964
2965 GCMutexLocker mu(SystemDictionary_lock);
2966
2967 // Verify dictionary
2968 ClassLoaderDataGraph::verify_dictionary();
2969
2970 placeholders()->verify();
2971
2972 // Verify constraint table
2973 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2974 constraints()->verify(placeholders());
2975
2976 _pd_cache_table->verify();
2977 }
2978
2979 void SystemDictionary::dump(outputStream *st, bool verbose) {
2980 assert_locked_or_safepoint(SystemDictionary_lock);
2981 if (verbose) {
2982 print_on(st);
2983 } else {
2984 if (shared_dictionary() != NULL) {
2985 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2986 }
2987 ClassLoaderDataGraph::print_dictionary_statistics(st);
2988 placeholders()->print_table_statistics(st, "Placeholder Table");
2989 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2990 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2991 }
2992 }
2993
2994 // Utility for dumping dictionaries.
2995 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2996 DCmdWithParser(output, heap),
2997 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2998 "BOOLEAN", false, "false") {
2999 _dcmdparser.add_dcmd_option(&_verbose);
3000 }
3001
3002 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3003 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3004 _verbose.value());
3005 VMThread::execute(&dumper);
3006 }
3007
3008 int SystemDictionaryDCmd::num_arguments() {
3009 ResourceMark rm;
3010 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3011 if (dcmd != NULL) {
3012 DCmdMark mark(dcmd);
3013 return dcmd->_dcmdparser.num_arguments();
3014 } else {
3015 return 0;
3016 }
3017 }
3018
3019 class CombineDictionariesClosure : public CLDClosure {
3020 private:
3021 Dictionary* _master_dictionary;
3022 public:
3023 CombineDictionariesClosure(Dictionary* master_dictionary) :
3024 _master_dictionary(master_dictionary) {}
3025 void do_cld(ClassLoaderData* cld) {
3026 ResourceMark rm;
3027 if (cld->is_unsafe_anonymous()) {
3028 return;
3029 }
3030 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3031 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3032 Dictionary* curr_dictionary = cld->dictionary();
3033 DictionaryEntry* p = curr_dictionary->bucket(i);
3034 while (p != NULL) {
3035 Symbol* name = p->instance_klass()->name();
3036 unsigned int d_hash = _master_dictionary->compute_hash(name);
3037 int d_index = _master_dictionary->hash_to_index(d_hash);
3038 DictionaryEntry* next = p->next();
3039 if (p->literal()->class_loader_data() != cld) {
3040 // This is an initiating class loader entry; don't use it
3041 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3042 curr_dictionary->free_entry(p);
3043 } else {
3044 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3045 curr_dictionary->unlink_entry(p);
3046 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3047 _master_dictionary->add_entry(d_index, p);
3048 }
3049 p = next;
3050 }
3051 *curr_dictionary->bucket_addr(i) = NULL;
3052 }
3053 }
3054 }
3055 };
3056
3057 // Combining platform and system loader dictionaries into boot loader dictionary.
3058 // During run time, we only have one shared dictionary.
3059 void SystemDictionary::combine_shared_dictionaries() {
3060 assert(DumpSharedSpaces, "dump time only");
3061 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3062 CombineDictionariesClosure cdc(master_dictionary);
3063 ClassLoaderDataGraph::cld_do(&cdc);
3064
3065 // These tables are no longer valid or necessary. Keeping them around will
3066 // cause SystemDictionary::verify() to fail. Let's empty them.
3067 _placeholders = new PlaceholderTable(_placeholder_table_size);
3068 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3069
3070 NOT_PRODUCT(SystemDictionary::verify());
3071 }
3072
3073 void SystemDictionary::initialize_oop_storage() {
3074 _vm_weak_oop_storage =
3075 new OopStorage("VM Weak Oop Handles",
3076 VMWeakAlloc_lock,
3077 VMWeakActive_lock);
3078 }
3079
3080 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3081 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3082 return _vm_weak_oop_storage;
3083 }