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