1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "gc/shared/oopStorage.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "jfr/jfrEvents.hpp"
51 #include "logging/log.hpp"
52 #include "logging/logStream.hpp"
53 #include "memory/filemap.hpp"
54 #include "memory/metaspaceClosure.hpp"
55 #include "memory/oopFactory.hpp"
56 #include "memory/resourceArea.hpp"
57 #include "oops/access.inline.hpp"
58 #include "oops/instanceKlass.hpp"
59 #include "oops/instanceRefKlass.hpp"
60 #include "oops/klass.inline.hpp"
61 #include "oops/method.inline.hpp"
62 #include "oops/methodData.hpp"
63 #include "oops/objArrayKlass.hpp"
64 #include "oops/objArrayOop.inline.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "oops/symbol.hpp"
67 #include "oops/typeArrayKlass.hpp"
68 #include "prims/jvmtiEnvBase.hpp"
69 #include "prims/resolvedMethodTable.hpp"
70 #include "prims/methodHandles.hpp"
71 #include "runtime/arguments.hpp"
72 #include "runtime/arguments_ext.hpp"
73 #include "runtime/biasedLocking.hpp"
74 #include "runtime/fieldType.hpp"
75 #include "runtime/handles.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "runtime/orderAccess.hpp"
80 #include "runtime/sharedRuntime.hpp"
81 #include "runtime/signature.hpp"
82 #include "services/classLoadingService.hpp"
83 #include "services/diagnosticCommand.hpp"
84 #include "services/threadService.hpp"
85 #include "utilities/macros.hpp"
86 #if INCLUDE_CDS
87 #include "classfile/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_checkPackageAccess = false;
112
113 // Default ProtectionDomainCacheSize value
114
115 const int defaultProtectionDomainCacheSize = 1009;
116
117 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149 }
150
151 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
152 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
153 return ClassLoaderDataGraph::find_or_create(class_loader);
154 }
155
156 // ----------------------------------------------------------------------------
157 // Parallel class loading check
158
159 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
160 if (class_loader.is_null()) return true;
161 if (AlwaysLockClassLoader) return false;
162 return java_lang_ClassLoader::parallelCapable(class_loader());
163 }
164 // ----------------------------------------------------------------------------
165 // ParallelDefineClass flag does not apply to bootclass loader
166 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
167 if (class_loader.is_null()) return false;
168 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
169 return true;
170 }
171 return false;
172 }
173
174 // Returns true if the passed class loader is the builtin application class loader
175 // or a custom system class loader. A customer system class loader can be
176 // specified via -Djava.system.class.loader.
177 bool SystemDictionary::is_system_class_loader(oop class_loader) {
178 if (class_loader == NULL) {
179 return false;
180 }
181 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
182 oopDesc::equals(class_loader, _java_system_loader));
183 }
184
185 // Returns true if the passed class loader is the platform class loader.
186 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
187 if (class_loader == NULL) {
188 return false;
189 }
190 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
191 }
192
193 // ----------------------------------------------------------------------------
194 // Resolving of classes
195
196 // Forwards to resolve_or_null
197
198 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
199 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
200 if (HAS_PENDING_EXCEPTION || klass == NULL) {
201 // can return a null klass
202 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
203 }
204 return klass;
205 }
206
207 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
208 bool throw_error,
209 Klass* klass, TRAPS) {
210 if (HAS_PENDING_EXCEPTION) {
211 // If we have a pending exception we forward it to the caller, unless throw_error is true,
212 // in which case we have to check whether the pending exception is a ClassNotFoundException,
213 // and if so convert it to a NoClassDefFoundError
214 // And chain the original ClassNotFoundException
215 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
216 ResourceMark rm(THREAD);
217 assert(klass == NULL, "Should not have result with exception pending");
218 Handle e(THREAD, PENDING_EXCEPTION);
219 CLEAR_PENDING_EXCEPTION;
220 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
221 } else {
222 return NULL;
223 }
224 }
225 // Class not found, throw appropriate error or exception depending on value of throw_error
226 if (klass == NULL) {
227 ResourceMark rm(THREAD);
228 if (throw_error) {
229 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
230 } else {
231 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
232 }
233 }
234 return klass;
235 }
236
237
238 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
239 bool throw_error, TRAPS)
240 {
241 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
242 }
243
244
245 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
246
247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
248 if (FieldType::is_array(class_name)) {
249 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
250 } else {
251 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
252 }
253 }
254
255 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
256 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
257 Handle class_loader,
258 Handle protection_domain,
259 TRAPS) {
260 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
261 if (FieldType::is_obj(class_name)) {
262 ResourceMark rm(THREAD);
263 // Ignore wrapping L and ;.
264 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
265 class_name->utf8_length() - 2, CHECK_NULL);
266 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
267 } else {
268 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
269 }
270 }
271
272 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
273 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
274 }
275
276 // Forwards to resolve_instance_class_or_null
277
278 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
279 Handle class_loader,
280 Handle protection_domain,
281 TRAPS) {
282 assert(FieldType::is_array(class_name), "must be array");
283 Klass* k = NULL;
284 FieldArrayInfo fd;
285 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
286 // of this call
287 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
288 if (t == T_OBJECT) {
289 // naked oop "k" is OK here -- we assign back into it
290 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
291 class_loader,
292 protection_domain,
293 CHECK_NULL);
294 if (k != NULL) {
295 k = k->array_klass(fd.dimension(), CHECK_NULL);
296 }
297 } else {
298 k = Universe::typeArrayKlassObj(t);
299 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
300 }
301 return k;
302 }
303
304
305 // Must be called for any super-class or super-interface resolution
306 // during class definition to allow class circularity checking
307 // super-interface callers:
308 // parse_interfaces - for defineClass & jvmtiRedefineClasses
309 // super-class callers:
310 // ClassFileParser - for defineClass & jvmtiRedefineClasses
311 // load_shared_class - while loading a class from shared archive
312 // resolve_instance_class_or_null:
313 // via: handle_parallel_super_load
314 // when resolving a class that has an existing placeholder with
315 // a saved superclass [i.e. a defineClass is currently in progress]
316 // if another thread is trying to resolve the class, it must do
317 // super-class checks on its own thread to catch class circularity
318 // This last call is critical in class circularity checking for cases
319 // where classloading is delegated to different threads and the
320 // classloader lock is released.
321 // Take the case: Base->Super->Base
322 // 1. If thread T1 tries to do a defineClass of class Base
323 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
324 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
325 // so it tries to load Super
326 // 3. If we load the class internally, or user classloader uses same thread
327 // loadClassFromxxx or defineClass via parseClassFile Super ...
328 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
329 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
330 // 3.4 calls resolve_super_or_fail Base
331 // 3.5 finds T1,Base -> throws class circularity
332 //OR 4. If T2 tries to resolve Super via defineClass Super ...
333 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
334 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
335 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
336 // 4.4 finds T2, Super -> throws class circularity
337 // Must be called, even if superclass is null, since this is
338 // where the placeholder entry is created which claims this
339 // thread is loading this class/classloader.
340 // Be careful when modifying this code: once you have run
341 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
342 // you need to find_and_remove it before returning.
343 // So be careful to not exit with a CHECK_ macro betweeen these calls.
344 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
345 Symbol* super_name,
346 Handle class_loader,
347 Handle protection_domain,
348 bool is_superclass,
349 TRAPS) {
350 assert(!FieldType::is_array(super_name), "invalid super class name");
351 #if INCLUDE_CDS
352 if (DumpSharedSpaces) {
353 // Special processing for CDS dump time.
354 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
355 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
356 if (k) {
357 return k;
358 }
359 }
360 #endif // INCLUDE_CDS
361
362 // Double-check, if child class is already loaded, just return super-class,interface
363 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
364 // dictionary.
365 // Make sure there's a placeholder for the *child* before resolving.
366 // Used as a claim that this thread is currently loading superclass/classloader
367 // Used here for ClassCircularity checks and also for heap verification
368 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
369 // Must check ClassCircularity before checking if super class is already loaded.
370 //
371 // We might not already have a placeholder if this child_name was
372 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
373 // the name of the class might not be known until the stream is actually
374 // parsed.
375 // Bugs 4643874, 4715493
376
377 ClassLoaderData* loader_data = class_loader_data(class_loader);
378 Dictionary* dictionary = loader_data->dictionary();
379 unsigned int d_hash = dictionary->compute_hash(child_name);
380 unsigned int p_hash = placeholders()->compute_hash(child_name);
381 int p_index = placeholders()->hash_to_index(p_hash);
382 // can't throw error holding a lock
383 bool child_already_loaded = false;
384 bool throw_circularity_error = false;
385 {
386 MutexLocker mu(SystemDictionary_lock, THREAD);
387 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
388 InstanceKlass* quicksuperk;
389 // to support // loading: if child done loading, just return superclass
390 // if super_name, & class_loader don't match:
391 // if initial define, SD update will give LinkageError
392 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
393 // so we don't throw an exception here.
394 // see: nsk redefclass014 & java.lang.instrument Instrument032
395 if ((childk != NULL ) && (is_superclass) &&
396 ((quicksuperk = childk->java_super()) != NULL) &&
397 ((quicksuperk->name() == super_name) &&
398 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
399 return quicksuperk;
400 } else {
401 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
402 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
403 throw_circularity_error = true;
404 }
405 }
406 if (!throw_circularity_error) {
407 // Be careful not to exit resolve_super
408 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
409 }
410 }
411 if (throw_circularity_error) {
412 ResourceMark rm(THREAD);
413 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
414 }
415
416 // java.lang.Object should have been found above
417 assert(super_name != NULL, "null super class for resolving");
418 // Resolve the super class or interface, check results on return
419 InstanceKlass* superk =
420 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
421 class_loader,
422 protection_domain,
423 THREAD);
424
425 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
426 // It is no longer necessary to keep the placeholder table alive until update_dictionary
427 // or error. GC used to walk the placeholder table as strong roots.
428 // The instanceKlass is kept alive because the class loader is on the stack,
429 // which keeps the loader_data alive, as well as all instanceKlasses in
430 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
431 {
432 MutexLocker mu(SystemDictionary_lock, THREAD);
433 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
434 SystemDictionary_lock->notify_all();
435 }
436 if (HAS_PENDING_EXCEPTION || superk == NULL) {
437 // can null superk
438 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
439 assert(k == NULL || k == superk, "must be");
440 if (k == NULL) {
441 superk = NULL;
442 }
443 }
444
445 return superk;
446 }
447
448 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
449 Handle class_loader,
450 Handle protection_domain,
451 TRAPS) {
452 if(!has_checkPackageAccess()) return;
453
454 // Now we have to call back to java to check if the initating class has access
455 JavaValue result(T_VOID);
456 LogTarget(Debug, protectiondomain) lt;
457 if (lt.is_enabled()) {
458 ResourceMark rm;
459 // Print out trace information
460 LogStream ls(lt);
461 ls.print_cr("Checking package access");
462 if (class_loader() != NULL) {
463 ls.print("class loader: ");
464 class_loader()->print_value_on(&ls);
465 } else {
466 ls.print_cr("class loader: NULL");
467 }
468 if (protection_domain() != NULL) {
469 ls.print(" protection domain: ");
470 protection_domain()->print_value_on(&ls);
471 } else {
472 ls.print_cr(" protection domain: NULL");
473 }
474 ls.print(" loading: "); klass->print_value_on(&ls);
475 ls.cr();
476 }
477
478 // This handle and the class_loader handle passed in keeps this class from
479 // being unloaded through several GC points.
480 // The class_loader handle passed in is the initiating loader.
481 Handle mirror(THREAD, klass->java_mirror());
482
483 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
484 JavaCalls::call_special(&result,
485 class_loader,
486 system_loader,
487 vmSymbols::checkPackageAccess_name(),
488 vmSymbols::class_protectiondomain_signature(),
489 mirror,
490 protection_domain,
491 THREAD);
492
493 if (HAS_PENDING_EXCEPTION) {
494 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
495 } else {
496 log_debug(protectiondomain)("granted");
497 }
498
499 if (HAS_PENDING_EXCEPTION) return;
500
501 // If no exception has been thrown, we have validated the protection domain
502 // Insert the protection domain of the initiating class into the set.
503 {
504 ClassLoaderData* loader_data = class_loader_data(class_loader);
505 Dictionary* dictionary = loader_data->dictionary();
506
507 Symbol* kn = klass->name();
508 unsigned int d_hash = dictionary->compute_hash(kn);
509
510 MutexLocker mu(SystemDictionary_lock, THREAD);
511 int d_index = dictionary->hash_to_index(d_hash);
512 dictionary->add_protection_domain(d_index, d_hash, klass,
513 protection_domain, THREAD);
514 }
515 }
516
517 // We only get here if this thread finds that another thread
518 // has already claimed the placeholder token for the current operation,
519 // but that other thread either never owned or gave up the
520 // object lock
521 // Waits on SystemDictionary_lock to indicate placeholder table updated
522 // On return, caller must recheck placeholder table state
523 //
524 // We only get here if
525 // 1) custom classLoader, i.e. not bootstrap classloader
526 // 2) custom classLoader has broken the class loader objectLock
527 // so another thread got here in parallel
528 //
529 // lockObject must be held.
530 // Complicated dance due to lock ordering:
531 // Must first release the classloader object lock to
532 // allow initial definer to complete the class definition
533 // and to avoid deadlock
534 // Reclaim classloader lock object with same original recursion count
535 // Must release SystemDictionary_lock after notify, since
536 // class loader lock must be claimed before SystemDictionary_lock
537 // to prevent deadlocks
538 //
539 // The notify allows applications that did an untimed wait() on
540 // the classloader object lock to not hang.
541 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
542 assert_lock_strong(SystemDictionary_lock);
543
544 bool calledholdinglock
545 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
546 assert(calledholdinglock,"must hold lock for notify");
547 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
548 ObjectSynchronizer::notifyall(lockObject, THREAD);
549 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
550 SystemDictionary_lock->wait();
551 SystemDictionary_lock->unlock();
552 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
553 SystemDictionary_lock->lock();
554 }
555
556 // If the class in is in the placeholder table, class loading is in progress
557 // For cases where the application changes threads to load classes, it
558 // is critical to ClassCircularity detection that we try loading
559 // the superclass on the same thread internally, so we do parallel
560 // super class loading here.
561 // This also is critical in cases where the original thread gets stalled
562 // even in non-circularity situations.
563 // Note: must call resolve_super_or_fail even if null super -
564 // to force placeholder entry creation for this class for circularity detection
565 // Caller must check for pending exception
566 // Returns non-null Klass* if other thread has completed load
567 // and we are done,
568 // If return null Klass* and no pending exception, the caller must load the class
569 InstanceKlass* SystemDictionary::handle_parallel_super_load(
570 Symbol* name, Symbol* superclassname, Handle class_loader,
571 Handle protection_domain, Handle lockObject, TRAPS) {
572
573 ClassLoaderData* loader_data = class_loader_data(class_loader);
574 Dictionary* dictionary = loader_data->dictionary();
575 unsigned int d_hash = dictionary->compute_hash(name);
576 unsigned int p_hash = placeholders()->compute_hash(name);
577 int p_index = placeholders()->hash_to_index(p_hash);
578
579 // superk is not used, resolve_super called for circularity check only
580 // This code is reached in two situations. One if this thread
581 // is loading the same class twice (e.g. ClassCircularity, or
582 // java.lang.instrument).
583 // The second is if another thread started the resolve_super first
584 // and has not yet finished.
585 // In both cases the original caller will clean up the placeholder
586 // entry on error.
587 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
588 superclassname,
589 class_loader,
590 protection_domain,
591 true,
592 CHECK_NULL);
593
594 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
595 // Serial class loaders and bootstrap classloader do wait for superclass loads
596 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
597 MutexLocker mu(SystemDictionary_lock, THREAD);
598 // Check if classloading completed while we were loading superclass or waiting
599 return find_class(d_hash, name, dictionary);
600 }
601
602 // must loop to both handle other placeholder updates
603 // and spurious notifications
604 bool super_load_in_progress = true;
605 PlaceholderEntry* placeholder;
606 while (super_load_in_progress) {
607 MutexLocker mu(SystemDictionary_lock, THREAD);
608 // Check if classloading completed while we were loading superclass or waiting
609 InstanceKlass* check = find_class(d_hash, name, dictionary);
610 if (check != NULL) {
611 // Klass is already loaded, so just return it
612 return check;
613 } else {
614 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
615 if (placeholder && placeholder->super_load_in_progress() ){
616 // We only get here if the application has released the
617 // classloader lock when another thread was in the middle of loading a
618 // superclass/superinterface for this class, and now
619 // this thread is also trying to load this class.
620 // To minimize surprises, the first thread that started to
621 // load a class should be the one to complete the loading
622 // with the classfile it initially expected.
623 // This logic has the current thread wait once it has done
624 // all the superclass/superinterface loading it can, until
625 // the original thread completes the class loading or fails
626 // If it completes we will use the resulting InstanceKlass
627 // which we will find below in the systemDictionary.
628 // We also get here for parallel bootstrap classloader
629 if (class_loader.is_null()) {
630 SystemDictionary_lock->wait();
631 } else {
632 double_lock_wait(lockObject, THREAD);
633 }
634 } else {
635 // If not in SD and not in PH, other thread's load must have failed
636 super_load_in_progress = false;
637 }
638 }
639 }
640 return NULL;
641 }
642
643 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
644 assert(event != NULL, "invariant");
645 assert(k != NULL, "invariant");
646 assert(event->should_commit(), "invariant");
647 event->set_loadedClass(k);
648 event->set_definingClassLoader(k->class_loader_data());
649 event->set_initiatingClassLoader(init_cld);
650 event->commit();
651 }
652
653
654 // Be careful when modifying this code: once you have run
655 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
656 // you need to find_and_remove it before returning.
657 // So be careful to not exit with a CHECK_ macro betweeen these calls.
658 //
659 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
660 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
661 Handle class_loader,
662 Handle protection_domain,
663 TRAPS) {
664 assert(name != NULL && !FieldType::is_array(name) &&
665 !FieldType::is_obj(name), "invalid class name");
666
667 EventClassLoad class_load_start_event;
668
669 HandleMark hm(THREAD);
670
671 // Fix for 4474172; see evaluation for more details
672 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
673 ClassLoaderData* loader_data = register_loader(class_loader);
674 Dictionary* dictionary = loader_data->dictionary();
675 unsigned int d_hash = dictionary->compute_hash(name);
676
677 // Do lookup to see if class already exist and the protection domain
678 // has the right access
679 // This call uses find which checks protection domain already matches
680 // All subsequent calls use find_class, and set has_loaded_class so that
681 // before we return a result we call out to java to check for valid protection domain
682 // to allow returning the Klass* and add it to the pd_set if it is valid
683 {
684 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
685 if (probe != NULL) return probe;
686 }
687
688 // Non-bootstrap class loaders will call out to class loader and
689 // define via jvm/jni_DefineClass which will acquire the
690 // class loader object lock to protect against multiple threads
691 // defining the class in parallel by accident.
692 // This lock must be acquired here so the waiter will find
693 // any successful result in the SystemDictionary and not attempt
694 // the define.
695 // ParallelCapable Classloaders and the bootstrap classloader
696 // do not acquire lock here.
697 bool DoObjectLock = true;
698 if (is_parallelCapable(class_loader)) {
699 DoObjectLock = false;
700 }
701
702 unsigned int p_hash = placeholders()->compute_hash(name);
703 int p_index = placeholders()->hash_to_index(p_hash);
704
705 // Class is not in SystemDictionary so we have to do loading.
706 // Make sure we are synchronized on the class loader before we proceed
707 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
708 check_loader_lock_contention(lockObject, THREAD);
709 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
710
711 // Check again (after locking) if class already exist in SystemDictionary
712 bool class_has_been_loaded = false;
713 bool super_load_in_progress = false;
714 bool havesupername = false;
715 InstanceKlass* k = NULL;
716 PlaceholderEntry* placeholder;
717 Symbol* superclassname = NULL;
718
719 assert(THREAD->can_call_java(),
720 "can not load classes with compiler thread: class=%s, classloader=%s",
721 name->as_C_string(),
722 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
723 {
724 MutexLocker mu(SystemDictionary_lock, THREAD);
725 InstanceKlass* check = find_class(d_hash, name, dictionary);
726 if (check != NULL) {
727 // InstanceKlass is already loaded, so just return it
728 class_has_been_loaded = true;
729 k = check;
730 } else {
731 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
732 if (placeholder && placeholder->super_load_in_progress()) {
733 super_load_in_progress = true;
734 if (placeholder->havesupername() == true) {
735 superclassname = placeholder->supername();
736 havesupername = true;
737 }
738 }
739 }
740 }
741
742 // If the class is in the placeholder table, class loading is in progress
743 if (super_load_in_progress && havesupername==true) {
744 k = handle_parallel_super_load(name,
745 superclassname,
746 class_loader,
747 protection_domain,
748 lockObject, THREAD);
749 if (HAS_PENDING_EXCEPTION) {
750 return NULL;
751 }
752 if (k != NULL) {
753 class_has_been_loaded = true;
754 }
755 }
756
757 bool throw_circularity_error = false;
758 if (!class_has_been_loaded) {
759 bool load_instance_added = false;
760
761 // add placeholder entry to record loading instance class
762 // Five cases:
763 // All cases need to prevent modifying bootclasssearchpath
764 // in parallel with a classload of same classname
765 // Redefineclasses uses existence of the placeholder for the duration
766 // of the class load to prevent concurrent redefinition of not completely
767 // defined classes.
768 // case 1. traditional classloaders that rely on the classloader object lock
769 // - no other need for LOAD_INSTANCE
770 // case 2. traditional classloaders that break the classloader object lock
771 // as a deadlock workaround. Detection of this case requires that
772 // this check is done while holding the classloader object lock,
773 // and that lock is still held when calling classloader's loadClass.
774 // For these classloaders, we ensure that the first requestor
775 // completes the load and other requestors wait for completion.
776 // case 3. Bootstrap classloader - don't own objectLocker
777 // This classloader supports parallelism at the classloader level,
778 // but only allows a single load of a class/classloader pair.
779 // No performance benefit and no deadlock issues.
780 // case 4. parallelCapable user level classloaders - without objectLocker
781 // Allow parallel classloading of a class/classloader pair
782
783 {
784 MutexLocker mu(SystemDictionary_lock, THREAD);
785 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
786 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
787 if (oldprobe) {
788 // only need check_seen_thread once, not on each loop
789 // 6341374 java/lang/Instrument with -Xcomp
790 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
791 throw_circularity_error = true;
792 } else {
793 // case 1: traditional: should never see load_in_progress.
794 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
795
796 // case 3: bootstrap classloader: prevent futile classloading,
797 // wait on first requestor
798 if (class_loader.is_null()) {
799 SystemDictionary_lock->wait();
800 } else {
801 // case 2: traditional with broken classloader lock. wait on first
802 // requestor.
803 double_lock_wait(lockObject, THREAD);
804 }
805 // Check if classloading completed while we were waiting
806 InstanceKlass* check = find_class(d_hash, name, dictionary);
807 if (check != NULL) {
808 // Klass is already loaded, so just return it
809 k = check;
810 class_has_been_loaded = true;
811 }
812 // check if other thread failed to load and cleaned up
813 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
814 }
815 }
816 }
817 }
818 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
819 // case 4: parallelCapable: allow competing threads to try
820 // LOAD_INSTANCE in parallel
821
822 if (!throw_circularity_error && !class_has_been_loaded) {
823 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
824 load_instance_added = true;
825 // For class loaders that do not acquire the classloader object lock,
826 // if they did not catch another thread holding LOAD_INSTANCE,
827 // need a check analogous to the acquire ObjectLocker/find_class
828 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
829 // one final check if the load has already completed
830 // class loaders holding the ObjectLock shouldn't find the class here
831 InstanceKlass* check = find_class(d_hash, name, dictionary);
832 if (check != NULL) {
833 // Klass is already loaded, so return it after checking/adding protection domain
834 k = check;
835 class_has_been_loaded = true;
836 }
837 }
838 }
839
840 // must throw error outside of owning lock
841 if (throw_circularity_error) {
842 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
843 ResourceMark rm(THREAD);
844 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
845 }
846
847 if (!class_has_been_loaded) {
848
849 // Do actual loading
850 k = load_instance_class(name, class_loader, THREAD);
851
852 // If everything was OK (no exceptions, no null return value), and
853 // class_loader is NOT the defining loader, do a little more bookkeeping.
854 if (!HAS_PENDING_EXCEPTION && k != NULL &&
855 !oopDesc::equals(k->class_loader(), class_loader())) {
856
857 check_constraints(d_hash, k, class_loader, false, THREAD);
858
859 // Need to check for a PENDING_EXCEPTION again; check_constraints
860 // can throw and doesn't use the CHECK macro.
861 if (!HAS_PENDING_EXCEPTION) {
862 { // Grabbing the Compile_lock prevents systemDictionary updates
863 // during compilations.
864 MutexLocker mu(Compile_lock, THREAD);
865 update_dictionary(d_hash, p_index, p_hash,
866 k, class_loader, THREAD);
867 }
868
869 if (JvmtiExport::should_post_class_load()) {
870 Thread *thread = THREAD;
871 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
872 JvmtiExport::post_class_load((JavaThread *) thread, k);
873 }
874 }
875 }
876 } // load_instance_class
877
878 if (load_instance_added == true) {
879 // clean up placeholder entries for LOAD_INSTANCE success or error
880 // This brackets the SystemDictionary updates for both defining
881 // and initiating loaders
882 MutexLocker mu(SystemDictionary_lock, THREAD);
883 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
884 SystemDictionary_lock->notify_all();
885 }
886 }
887
888 if (HAS_PENDING_EXCEPTION || k == NULL) {
889 return NULL;
890 }
891 if (class_load_start_event.should_commit()) {
892 post_class_load_event(&class_load_start_event, k, loader_data);
893 }
894 #ifdef ASSERT
895 {
896 ClassLoaderData* loader_data = k->class_loader_data();
897 MutexLocker mu(SystemDictionary_lock, THREAD);
898 InstanceKlass* kk = find_class(name, loader_data);
899 assert(kk == k, "should be present in dictionary");
900 }
901 #endif
902
903 // return if the protection domain in NULL
904 if (protection_domain() == NULL) return k;
905
906 // Check the protection domain has the right access
907 if (dictionary->is_valid_protection_domain(d_hash, name,
908 protection_domain)) {
909 return k;
910 }
911
912 // Verify protection domain. If it fails an exception is thrown
913 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
914
915 return k;
916 }
917
918
919 // This routine does not lock the system dictionary.
920 //
921 // Since readers don't hold a lock, we must make sure that system
922 // dictionary entries are only removed at a safepoint (when only one
923 // thread is running), and are added to in a safe way (all links must
924 // be updated in an MT-safe manner).
925 //
926 // Callers should be aware that an entry could be added just after
927 // _dictionary->bucket(index) is read here, so the caller will not see
928 // the new entry.
929
930 Klass* SystemDictionary::find(Symbol* class_name,
931 Handle class_loader,
932 Handle protection_domain,
933 TRAPS) {
934
935 // The result of this call should be consistent with the result
936 // of the call to resolve_instance_class_or_null().
937 // See evaluation 6790209 and 4474172 for more details.
938 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
939 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
940
941 if (loader_data == NULL) {
942 // If the ClassLoaderData has not been setup,
943 // then the class loader has no entries in the dictionary.
944 return NULL;
945 }
946
947 Dictionary* dictionary = loader_data->dictionary();
948 unsigned int d_hash = dictionary->compute_hash(class_name);
949 return dictionary->find(d_hash, class_name,
950 protection_domain);
951 }
952
953
954 // Look for a loaded instance or array klass by name. Do not do any loading.
955 // return NULL in case of error.
956 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
957 Handle class_loader,
958 Handle protection_domain,
959 TRAPS) {
960 Klass* k = NULL;
961 assert(class_name != NULL, "class name must be non NULL");
962
963 if (FieldType::is_array(class_name)) {
964 // The name refers to an array. Parse the name.
965 // dimension and object_key in FieldArrayInfo are assigned as a
966 // side-effect of this call
967 FieldArrayInfo fd;
968 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
969 if (t != T_OBJECT) {
970 k = Universe::typeArrayKlassObj(t);
971 } else {
972 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
973 }
974 if (k != NULL) {
975 k = k->array_klass_or_null(fd.dimension());
976 }
977 } else {
978 k = find(class_name, class_loader, protection_domain, THREAD);
979 }
980 return k;
981 }
982
983 // Note: this method is much like resolve_from_stream, but
984 // does not publish the classes via the SystemDictionary.
985 // Handles unsafe_DefineAnonymousClass and redefineclasses
986 // RedefinedClasses do not add to the class hierarchy
987 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
988 Handle class_loader,
989 Handle protection_domain,
990 ClassFileStream* st,
991 const InstanceKlass* host_klass,
992 GrowableArray<Handle>* cp_patches,
993 TRAPS) {
994
995 EventClassLoad class_load_start_event;
996
997 ClassLoaderData* loader_data;
998 if (host_klass != NULL) {
999 // Create a new CLD for anonymous class, that uses the same class loader
1000 // as the host_klass
1001 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
1002 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
1003 } else {
1004 loader_data = ClassLoaderData::class_loader_data(class_loader());
1005 }
1006
1007 assert(st != NULL, "invariant");
1008 assert(st->need_verify(), "invariant");
1009
1010 // Parse stream and create a klass.
1011 // Note that we do this even though this klass might
1012 // already be present in the SystemDictionary, otherwise we would not
1013 // throw potential ClassFormatErrors.
1014
1015 InstanceKlass* k = KlassFactory::create_from_stream(st,
1016 class_name,
1017 loader_data,
1018 protection_domain,
1019 host_klass,
1020 cp_patches,
1021 CHECK_NULL);
1022
1023 if (host_klass != NULL && k != NULL) {
1024 // Anonymous classes must update ClassLoaderData holder (was host_klass loader)
1025 // so that they can be unloaded when the mirror is no longer referenced.
1026 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1027
1028 {
1029 MutexLocker mu_r(Compile_lock, THREAD);
1030
1031 // Add to class hierarchy, initialize vtables, and do possible
1032 // deoptimizations.
1033 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1034
1035 // But, do not add to dictionary.
1036
1037 // compiled code dependencies need to be validated anyway
1038 notice_modification();
1039 }
1040
1041 // Rewrite and patch constant pool here.
1042 k->link_class(CHECK_NULL);
1043 if (cp_patches != NULL) {
1044 k->constants()->patch_resolved_references(cp_patches);
1045 }
1046
1047 // If it's anonymous, initialize it now, since nobody else will.
1048 k->eager_initialize(CHECK_NULL);
1049
1050 // notify jvmti
1051 if (JvmtiExport::should_post_class_load()) {
1052 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1053 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1054 }
1055 if (class_load_start_event.should_commit()) {
1056 post_class_load_event(&class_load_start_event, k, loader_data);
1057 }
1058 }
1059 assert(host_klass != NULL || NULL == cp_patches,
1060 "cp_patches only found with host_klass");
1061
1062 return k;
1063 }
1064
1065 // Add a klass to the system from a stream (called by jni_DefineClass and
1066 // JVM_DefineClass).
1067 // Note: class_name can be NULL. In that case we do not know the name of
1068 // the class until we have parsed the stream.
1069
1070 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1071 Handle class_loader,
1072 Handle protection_domain,
1073 ClassFileStream* st,
1074 TRAPS) {
1075
1076 HandleMark hm(THREAD);
1077
1078 // Classloaders that support parallelism, e.g. bootstrap classloader,
1079 // do not acquire lock here
1080 bool DoObjectLock = true;
1081 if (is_parallelCapable(class_loader)) {
1082 DoObjectLock = false;
1083 }
1084
1085 ClassLoaderData* loader_data = register_loader(class_loader);
1086
1087 // Make sure we are synchronized on the class loader before we proceed
1088 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1089 check_loader_lock_contention(lockObject, THREAD);
1090 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1091
1092 assert(st != NULL, "invariant");
1093
1094 // Parse the stream and create a klass.
1095 // Note that we do this even though this klass might
1096 // already be present in the SystemDictionary, otherwise we would not
1097 // throw potential ClassFormatErrors.
1098 InstanceKlass* k = NULL;
1099
1100 #if INCLUDE_CDS
1101 if (!DumpSharedSpaces) {
1102 k = SystemDictionaryShared::lookup_from_stream(class_name,
1103 class_loader,
1104 protection_domain,
1105 st,
1106 CHECK_NULL);
1107 }
1108 #endif
1109
1110 if (k == NULL) {
1111 if (st->buffer() == NULL) {
1112 return NULL;
1113 }
1114 k = KlassFactory::create_from_stream(st,
1115 class_name,
1116 loader_data,
1117 protection_domain,
1118 NULL, // host_klass
1119 NULL, // cp_patches
1120 CHECK_NULL);
1121 }
1122
1123 assert(k != NULL, "no klass created");
1124 Symbol* h_name = k->name();
1125 assert(class_name == NULL || class_name == h_name, "name mismatch");
1126
1127 // Add class just loaded
1128 // If a class loader supports parallel classloading handle parallel define requests
1129 // find_or_define_instance_class may return a different InstanceKlass
1130 if (is_parallelCapable(class_loader)) {
1131 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1132 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1133 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1134 assert(defined_k != NULL, "Should have a klass if there's no exception");
1135 loader_data->add_to_deallocate_list(k);
1136 k = defined_k;
1137 }
1138 } else {
1139 define_instance_class(k, THREAD);
1140 }
1141
1142 // If defining the class throws an exception register 'k' for cleanup.
1143 if (HAS_PENDING_EXCEPTION) {
1144 assert(k != NULL, "Must have an instance klass here!");
1145 loader_data->add_to_deallocate_list(k);
1146 return NULL;
1147 }
1148
1149 // Make sure we have an entry in the SystemDictionary on success
1150 debug_only( {
1151 MutexLocker mu(SystemDictionary_lock, THREAD);
1152
1153 Klass* check = find_class(h_name, k->class_loader_data());
1154 assert(check == k, "should be present in the dictionary");
1155 } );
1156
1157 return k;
1158 }
1159
1160 #if INCLUDE_CDS
1161 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1162 int number_of_entries) {
1163 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1164 "bad shared dictionary size.");
1165 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1166 _shared_dictionary_size, t, number_of_entries);
1167 }
1168
1169
1170 // If there is a shared dictionary, then find the entry for the
1171 // given shared system class, if any.
1172
1173 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1174 if (shared_dictionary() != NULL) {
1175 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1176 int d_index = shared_dictionary()->hash_to_index(d_hash);
1177
1178 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1179 } else {
1180 return NULL;
1181 }
1182 }
1183
1184
1185 // Load a class from the shared spaces (found through the shared system
1186 // dictionary). Force the superclass and all interfaces to be loaded.
1187 // Update the class definition to include sibling classes and no
1188 // subclasses (yet). [Classes in the shared space are not part of the
1189 // object hierarchy until loaded.]
1190
1191 InstanceKlass* SystemDictionary::load_shared_class(
1192 Symbol* class_name, Handle class_loader, TRAPS) {
1193 InstanceKlass* ik = find_shared_class(class_name);
1194 // Make sure we only return the boot class for the NULL classloader.
1195 if (ik != NULL &&
1196 ik->is_shared_boot_class() && class_loader.is_null()) {
1197 Handle protection_domain;
1198 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1199 }
1200 return NULL;
1201 }
1202
1203 // Check if a shared class can be loaded by the specific classloader:
1204 //
1205 // NULL classloader:
1206 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1207 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1208 // be defined in an unnamed module.
1209 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1210 InstanceKlass* ik,
1211 Handle class_loader, TRAPS) {
1212 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1213 "Cannot use sharing if java.base is patched");
1214 ResourceMark rm;
1215 int path_index = ik->shared_classpath_index();
1216 ClassLoaderData* loader_data = class_loader_data(class_loader);
1217 if (path_index < 0) {
1218 // path_index < 0 indicates that the class is intended for a custom loader
1219 // and should not be loaded by boot/platform/app loaders
1220 if (loader_data->is_builtin_class_loader_data()) {
1221 return false;
1222 } else {
1223 return true;
1224 }
1225 }
1226 SharedClassPathEntry* ent =
1227 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1228 if (!Universe::is_module_initialized()) {
1229 assert(ent != NULL && ent->is_modules_image(),
1230 "Loading non-bootstrap classes before the module system is initialized");
1231 assert(class_loader.is_null(), "sanity");
1232 return true;
1233 }
1234 // Get the pkg_entry from the classloader
1235 TempNewSymbol pkg_name = NULL;
1236 PackageEntry* pkg_entry = NULL;
1237 ModuleEntry* mod_entry = NULL;
1238 const char* pkg_string = NULL;
1239 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1240 if (pkg_name != NULL) {
1241 pkg_string = pkg_name->as_C_string();
1242 if (loader_data != NULL) {
1243 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1244 }
1245 if (pkg_entry != NULL) {
1246 mod_entry = pkg_entry->module();
1247 }
1248 }
1249
1250 // If the archived class is from a module that has been patched at runtime,
1251 // the class cannot be loaded from the archive.
1252 if (mod_entry != NULL && mod_entry->is_patched()) {
1253 return false;
1254 }
1255
1256 if (class_loader.is_null()) {
1257 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1258 // The NULL classloader can load archived class originated from the
1259 // "modules" jimage and the -Xbootclasspath/a. For class from the
1260 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1261 // by the NULL classloader.
1262 if (mod_entry != NULL) {
1263 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1264 // ModuleEntry's location agrees with the archived class' origination.
1265 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1266 return true; // Module class from the "module" jimage
1267 }
1268 }
1269
1270 // If the archived class is not from the "module" jimage, the class can be
1271 // loaded by the NULL classloader if
1272 //
1273 // 1. the class is from the unamed package
1274 // 2. or, the class is not from a module defined in the NULL classloader
1275 // 3. or, the class is from an unamed module
1276 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1277 // the class is from the -Xbootclasspath/a
1278 if (pkg_string == NULL ||
1279 pkg_entry == NULL ||
1280 pkg_entry->in_unnamed_module()) {
1281 assert(mod_entry == NULL ||
1282 mod_entry == loader_data->unnamed_module(),
1283 "the unnamed module is not defined in the classloader");
1284 return true;
1285 }
1286 }
1287 return false;
1288 } else {
1289 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1290 ik, class_loader, pkg_string, pkg_name,
1291 pkg_entry, mod_entry, CHECK_(false));
1292 return res;
1293 }
1294 }
1295
1296 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1297 Handle class_loader,
1298 Handle protection_domain, TRAPS) {
1299
1300 if (ik != NULL) {
1301 Symbol* class_name = ik->name();
1302
1303 bool visible = is_shared_class_visible(
1304 class_name, ik, class_loader, CHECK_NULL);
1305 if (!visible) {
1306 return NULL;
1307 }
1308
1309 // Resolve the superclass and interfaces. They must be the same
1310 // as in dump time, because the layout of <ik> depends on
1311 // the specific layout of ik->super() and ik->local_interfaces().
1312 //
1313 // If unexpected superclass or interfaces are found, we cannot
1314 // load <ik> from the shared archive.
1315
1316 if (ik->super() != NULL) {
1317 Symbol* cn = ik->super()->name();
1318 Klass *s = resolve_super_or_fail(class_name, cn,
1319 class_loader, protection_domain, true, CHECK_NULL);
1320 if (s != ik->super()) {
1321 // The dynamically resolved super class is not the same as the one we used during dump time,
1322 // so we cannot use ik.
1323 return NULL;
1324 } else {
1325 assert(s->is_shared(), "must be");
1326 }
1327 }
1328
1329 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1330 int num_interfaces = interfaces->length();
1331 for (int index = 0; index < num_interfaces; index++) {
1332 InstanceKlass* k = interfaces->at(index);
1333 Symbol* name = k->name();
1334 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1335 if (k != i) {
1336 // The dynamically resolved interface class is not the same as the one we used during dump time,
1337 // so we cannot use ik.
1338 return NULL;
1339 } else {
1340 assert(i->is_shared(), "must be");
1341 }
1342 }
1343
1344 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1345 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1346 if (new_ik != NULL) {
1347 // The class is changed by CFLH. Return the new class. The shared class is
1348 // not used.
1349 return new_ik;
1350 }
1351
1352 // Adjust methods to recover missing data. They need addresses for
1353 // interpreter entry points and their default native method address
1354 // must be reset.
1355
1356 // Updating methods must be done under a lock so multiple
1357 // threads don't update these in parallel
1358 //
1359 // Shared classes are all currently loaded by either the bootstrap or
1360 // internal parallel class loaders, so this will never cause a deadlock
1361 // on a custom class loader lock.
1362
1363 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1364 {
1365 HandleMark hm(THREAD);
1366 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1367 check_loader_lock_contention(lockObject, THREAD);
1368 ObjectLocker ol(lockObject, THREAD, true);
1369 // prohibited package check assumes all classes loaded from archive call
1370 // restore_unshareable_info which calls ik->set_package()
1371 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1372 }
1373
1374 ik->print_class_load_logging(loader_data, NULL, NULL);
1375
1376 // For boot loader, ensure that GetSystemPackage knows that a class in this
1377 // package was loaded.
1378 if (class_loader.is_null()) {
1379 int path_index = ik->shared_classpath_index();
1380 ResourceMark rm;
1381 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1382 }
1383
1384 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1385 // Only dump the classes that can be stored into CDS archive
1386 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1387 ResourceMark rm(THREAD);
1388 classlist_file->print_cr("%s", ik->name()->as_C_string());
1389 classlist_file->flush();
1390 }
1391 }
1392
1393 // notify a class loaded from shared object
1394 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1395
1396 ik->set_has_passed_fingerprint_check(false);
1397 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1398 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1399 uint64_t cds_fp = ik->get_stored_fingerprint();
1400 if (aot_fp != 0 && aot_fp == cds_fp) {
1401 // This class matches with a class saved in an AOT library
1402 ik->set_has_passed_fingerprint_check(true);
1403 } else {
1404 ResourceMark rm;
1405 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1406 }
1407 }
1408 }
1409 return ik;
1410 }
1411
1412 void SystemDictionary::clear_invoke_method_table() {
1413 SymbolPropertyEntry* spe = NULL;
1414 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1415 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1416 while (p != NULL) {
1417 spe = p;
1418 p = p->next();
1419 _invoke_method_table->free_entry(spe);
1420 }
1421 }
1422 }
1423 #endif // INCLUDE_CDS
1424
1425 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1426
1427 if (class_loader.is_null()) {
1428 ResourceMark rm;
1429 PackageEntry* pkg_entry = NULL;
1430 bool search_only_bootloader_append = false;
1431 ClassLoaderData *loader_data = class_loader_data(class_loader);
1432
1433 // Find the package in the boot loader's package entry table.
1434 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1435 if (pkg_name != NULL) {
1436 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1437 }
1438
1439 // Prior to attempting to load the class, enforce the boot loader's
1440 // visibility boundaries.
1441 if (!Universe::is_module_initialized()) {
1442 // During bootstrapping, prior to module initialization, any
1443 // class attempting to be loaded must be checked against the
1444 // java.base packages in the boot loader's PackageEntryTable.
1445 // No class outside of java.base is allowed to be loaded during
1446 // this bootstrapping window.
1447 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1448 // Class is either in the unnamed package or in
1449 // a named package within the unnamed module. Either
1450 // case is outside of java.base, do not attempt to
1451 // load the class post java.base definition. If
1452 // java.base has not been defined, let the class load
1453 // and its package will be checked later by
1454 // ModuleEntryTable::verify_javabase_packages.
1455 if (ModuleEntryTable::javabase_defined()) {
1456 return NULL;
1457 }
1458 } else {
1459 // Check that the class' package is defined within java.base.
1460 ModuleEntry* mod_entry = pkg_entry->module();
1461 Symbol* mod_entry_name = mod_entry->name();
1462 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1463 return NULL;
1464 }
1465 }
1466 } else {
1467 // After the module system has been initialized, check if the class'
1468 // package is in a module defined to the boot loader.
1469 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1470 // Class is either in the unnamed package, in a named package
1471 // within a module not defined to the boot loader or in a
1472 // a named package within the unnamed module. In all cases,
1473 // limit visibility to search for the class only in the boot
1474 // loader's append path.
1475 search_only_bootloader_append = true;
1476 }
1477 }
1478
1479 // Prior to bootstrapping's module initialization, never load a class outside
1480 // of the boot loader's module path
1481 assert(Universe::is_module_initialized() ||
1482 !search_only_bootloader_append,
1483 "Attempt to load a class outside of boot loader's module path");
1484
1485 // Search the shared system dictionary for classes preloaded into the
1486 // shared spaces.
1487 InstanceKlass* k = NULL;
1488 {
1489 #if INCLUDE_CDS
1490 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1491 k = load_shared_class(class_name, class_loader, THREAD);
1492 #endif
1493 }
1494
1495 if (k == NULL) {
1496 // Use VM class loader
1497 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1498 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1499 }
1500
1501 // find_or_define_instance_class may return a different InstanceKlass
1502 if (k != NULL) {
1503 InstanceKlass* defined_k =
1504 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1505 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1506 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1507 assert(defined_k != NULL, "Should have a klass if there's no exception");
1508 loader_data->add_to_deallocate_list(k);
1509 k = defined_k;
1510 } else if (HAS_PENDING_EXCEPTION) {
1511 loader_data->add_to_deallocate_list(k);
1512 return NULL;
1513 }
1514 }
1515 return k;
1516 } else {
1517 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1518 ResourceMark rm(THREAD);
1519
1520 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1521 JavaThread* jt = (JavaThread*) THREAD;
1522
1523 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1524 ClassLoader::perf_app_classload_selftime(),
1525 ClassLoader::perf_app_classload_count(),
1526 jt->get_thread_stat()->perf_recursion_counts_addr(),
1527 jt->get_thread_stat()->perf_timers_addr(),
1528 PerfClassTraceTime::CLASS_LOAD);
1529
1530 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1531 // Translate to external class name format, i.e., convert '/' chars to '.'
1532 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1533
1534 JavaValue result(T_OBJECT);
1535
1536 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1537
1538 // Call public unsynchronized loadClass(String) directly for all class loaders.
1539 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1540 // acquire a class-name based lock rather than the class loader object lock.
1541 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1542 JavaCalls::call_virtual(&result,
1543 class_loader,
1544 spec_klass,
1545 vmSymbols::loadClass_name(),
1546 vmSymbols::string_class_signature(),
1547 string,
1548 CHECK_NULL);
1549
1550 assert(result.get_type() == T_OBJECT, "just checking");
1551 oop obj = (oop) result.get_jobject();
1552
1553 // Primitive classes return null since forName() can not be
1554 // used to obtain any of the Class objects representing primitives or void
1555 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1556 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1557 // For user defined Java class loaders, check that the name returned is
1558 // the same as that requested. This check is done for the bootstrap
1559 // loader when parsing the class file.
1560 if (class_name == k->name()) {
1561 return k;
1562 }
1563 }
1564 // Class is not found or has the wrong name, return NULL
1565 return NULL;
1566 }
1567 }
1568
1569 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1570 EventClassDefine event;
1571 if (event.should_commit()) {
1572 event.set_definedClass(k);
1573 event.set_definingClassLoader(def_cld);
1574 event.commit();
1575 }
1576 }
1577
1578 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1579
1580 HandleMark hm(THREAD);
1581 ClassLoaderData* loader_data = k->class_loader_data();
1582 Handle class_loader_h(THREAD, loader_data->class_loader());
1583
1584 // for bootstrap and other parallel classloaders don't acquire lock,
1585 // use placeholder token
1586 // If a parallelCapable class loader calls define_instance_class instead of
1587 // find_or_define_instance_class to get here, we have a timing
1588 // hole with systemDictionary updates and check_constraints
1589 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1590 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1591 compute_loader_lock_object(class_loader_h, THREAD)),
1592 "define called without lock");
1593 }
1594
1595 // Check class-loading constraints. Throw exception if violation is detected.
1596 // Grabs and releases SystemDictionary_lock
1597 // The check_constraints/find_class call and update_dictionary sequence
1598 // must be "atomic" for a specific class/classloader pair so we never
1599 // define two different instanceKlasses for that class/classloader pair.
1600 // Existing classloaders will call define_instance_class with the
1601 // classloader lock held
1602 // Parallel classloaders will call find_or_define_instance_class
1603 // which will require a token to perform the define class
1604 Symbol* name_h = k->name();
1605 Dictionary* dictionary = loader_data->dictionary();
1606 unsigned int d_hash = dictionary->compute_hash(name_h);
1607 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1608
1609 // Register class just loaded with class loader (placed in Vector)
1610 // Note we do this before updating the dictionary, as this can
1611 // fail with an OutOfMemoryError (if it does, we will *not* put this
1612 // class in the dictionary and will not update the class hierarchy).
1613 // JVMTI FollowReferences needs to find the classes this way.
1614 if (k->class_loader() != NULL) {
1615 methodHandle m(THREAD, Universe::loader_addClass_method());
1616 JavaValue result(T_VOID);
1617 JavaCallArguments args(class_loader_h);
1618 args.push_oop(Handle(THREAD, k->java_mirror()));
1619 JavaCalls::call(&result, m, &args, CHECK);
1620 }
1621
1622 // Add the new class. We need recompile lock during update of CHA.
1623 {
1624 unsigned int p_hash = placeholders()->compute_hash(name_h);
1625 int p_index = placeholders()->hash_to_index(p_hash);
1626
1627 MutexLocker mu_r(Compile_lock, THREAD);
1628
1629 // Add to class hierarchy, initialize vtables, and do possible
1630 // deoptimizations.
1631 add_to_hierarchy(k, CHECK); // No exception, but can block
1632
1633 // Add to systemDictionary - so other classes can see it.
1634 // Grabs and releases SystemDictionary_lock
1635 update_dictionary(d_hash, p_index, p_hash,
1636 k, class_loader_h, THREAD);
1637 }
1638 k->eager_initialize(THREAD);
1639
1640 // notify jvmti
1641 if (JvmtiExport::should_post_class_load()) {
1642 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1643 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1644
1645 }
1646 post_class_define_event(k, loader_data);
1647 }
1648
1649 // Support parallel classloading
1650 // All parallel class loaders, including bootstrap classloader
1651 // lock a placeholder entry for this class/class_loader pair
1652 // to allow parallel defines of different classes for this class loader
1653 // With AllowParallelDefine flag==true, in case they do not synchronize around
1654 // FindLoadedClass/DefineClass, calls, we check for parallel
1655 // loading for them, wait if a defineClass is in progress
1656 // and return the initial requestor's results
1657 // This flag does not apply to the bootstrap classloader.
1658 // With AllowParallelDefine flag==false, call through to define_instance_class
1659 // which will throw LinkageError: duplicate class definition.
1660 // False is the requested default.
1661 // For better performance, the class loaders should synchronize
1662 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1663 // potentially waste time reading and parsing the bytestream.
1664 // Note: VM callers should ensure consistency of k/class_name,class_loader
1665 // Be careful when modifying this code: once you have run
1666 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1667 // you need to find_and_remove it before returning.
1668 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1669 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1670 InstanceKlass* k, TRAPS) {
1671
1672 Symbol* name_h = k->name(); // passed in class_name may be null
1673 ClassLoaderData* loader_data = class_loader_data(class_loader);
1674 Dictionary* dictionary = loader_data->dictionary();
1675
1676 unsigned int d_hash = dictionary->compute_hash(name_h);
1677
1678 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1679 unsigned int p_hash = placeholders()->compute_hash(name_h);
1680 int p_index = placeholders()->hash_to_index(p_hash);
1681 PlaceholderEntry* probe;
1682
1683 {
1684 MutexLocker mu(SystemDictionary_lock, THREAD);
1685 // First check if class already defined
1686 if (is_parallelDefine(class_loader)) {
1687 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1688 if (check != NULL) {
1689 return check;
1690 }
1691 }
1692
1693 // Acquire define token for this class/classloader
1694 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1695 // Wait if another thread defining in parallel
1696 // All threads wait - even those that will throw duplicate class: otherwise
1697 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1698 // if other thread has not finished updating dictionary
1699 while (probe->definer() != NULL) {
1700 SystemDictionary_lock->wait();
1701 }
1702 // Only special cases allow parallel defines and can use other thread's results
1703 // Other cases fall through, and may run into duplicate defines
1704 // caught by finding an entry in the SystemDictionary
1705 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1706 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1707 SystemDictionary_lock->notify_all();
1708 #ifdef ASSERT
1709 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1710 assert(check != NULL, "definer missed recording success");
1711 #endif
1712 return probe->instance_klass();
1713 } else {
1714 // This thread will define the class (even if earlier thread tried and had an error)
1715 probe->set_definer(THREAD);
1716 }
1717 }
1718
1719 define_instance_class(k, THREAD);
1720
1721 Handle linkage_exception = Handle(); // null handle
1722
1723 // definer must notify any waiting threads
1724 {
1725 MutexLocker mu(SystemDictionary_lock, THREAD);
1726 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1727 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1728 if (probe != NULL) {
1729 if (HAS_PENDING_EXCEPTION) {
1730 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1731 CLEAR_PENDING_EXCEPTION;
1732 } else {
1733 probe->set_instance_klass(k);
1734 }
1735 probe->set_definer(NULL);
1736 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1737 SystemDictionary_lock->notify_all();
1738 }
1739 }
1740
1741 // Can't throw exception while holding lock due to rank ordering
1742 if (linkage_exception() != NULL) {
1743 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1744 }
1745
1746 return k;
1747 }
1748
1749 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1750 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1751 if (class_loader.is_null()) {
1752 return Handle(THREAD, _system_loader_lock_obj);
1753 } else {
1754 return class_loader;
1755 }
1756 }
1757
1758 // This method is added to check how often we have to wait to grab loader
1759 // lock. The results are being recorded in the performance counters defined in
1760 // ClassLoader::_sync_systemLoaderLockContentionRate and
1761 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1762 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1763 if (!UsePerfData) {
1764 return;
1765 }
1766
1767 assert(!loader_lock.is_null(), "NULL lock object");
1768
1769 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1770 == ObjectSynchronizer::owner_other) {
1771 // contention will likely happen, so increment the corresponding
1772 // contention counter.
1773 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1774 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1775 } else {
1776 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1777 }
1778 }
1779 }
1780
1781 // ----------------------------------------------------------------------------
1782 // Lookup
1783
1784 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1785 Symbol* class_name,
1786 Dictionary* dictionary) {
1787 assert_locked_or_safepoint(SystemDictionary_lock);
1788 int index = dictionary->hash_to_index(hash);
1789 return dictionary->find_class(index, hash, class_name);
1790 }
1791
1792
1793 // Basic find on classes in the midst of being loaded
1794 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1795 ClassLoaderData* loader_data) {
1796 assert_locked_or_safepoint(SystemDictionary_lock);
1797 unsigned int p_hash = placeholders()->compute_hash(class_name);
1798 int p_index = placeholders()->hash_to_index(p_hash);
1799 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1800 }
1801
1802
1803 // Used for assertions and verification only
1804 // Precalculating the hash and index is an optimization because there are many lookups
1805 // before adding the class.
1806 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1807 assert_locked_or_safepoint(SystemDictionary_lock);
1808 #ifndef ASSERT
1809 guarantee(VerifyBeforeGC ||
1810 VerifyDuringGC ||
1811 VerifyBeforeExit ||
1812 VerifyDuringStartup ||
1813 VerifyAfterGC, "too expensive");
1814 #endif
1815
1816 Dictionary* dictionary = loader_data->dictionary();
1817 unsigned int d_hash = dictionary->compute_hash(class_name);
1818 return find_class(d_hash, class_name, dictionary);
1819 }
1820
1821
1822 // ----------------------------------------------------------------------------
1823 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1824 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1825 // before a new class is used.
1826
1827 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1828 assert(k != NULL, "just checking");
1829 assert_locked_or_safepoint(Compile_lock);
1830
1831 // Link into hierachy. Make sure the vtables are initialized before linking into
1832 k->append_to_sibling_list(); // add to superklass/sibling list
1833 k->process_interfaces(THREAD); // handle all "implements" declarations
1834 k->set_init_state(InstanceKlass::loaded);
1835 // Now flush all code that depended on old class hierarchy.
1836 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1837 // Also, first reinitialize vtable because it may have gotten out of synch
1838 // while the new class wasn't connected to the class hierarchy.
1839 CodeCache::flush_dependents_on(k);
1840 }
1841
1842 // ----------------------------------------------------------------------------
1843 // GC support
1844
1845 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1846 // Note: anonymous classes are not in the SD.
1847 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1848 bool do_cleaning) {
1849
1850 bool unloading_occurred;
1851 {
1852 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1853
1854 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1855 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1856 }
1857
1858 if (unloading_occurred) {
1859 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1860 constraints()->purge_loader_constraints();
1861 resolution_errors()->purge_resolution_errors();
1862 }
1863
1864 {
1865 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1866 // Oops referenced by the protection domain cache table may get unreachable independently
1867 // of the class loader (eg. cached protection domain oops). So we need to
1868 // explicitly unlink them here.
1869 _pd_cache_table->unlink();
1870 }
1871
1872 if (do_cleaning) {
1873 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1874 ResolvedMethodTable::unlink();
1875 }
1876
1877 return unloading_occurred;
1878 }
1879
1880 void SystemDictionary::oops_do(OopClosure* f) {
1881 f->do_oop(&_java_system_loader);
1882 f->do_oop(&_java_platform_loader);
1883 f->do_oop(&_system_loader_lock_obj);
1884 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1885
1886 // Visit extra methods
1887 invoke_method_table()->oops_do(f);
1888 }
1889
1890 // CDS: scan and relocate all classes in the system dictionary.
1891 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1892 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1893 }
1894
1895 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1896 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1897 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1898 it->push(well_known_klass_addr((WKID)id));
1899 }
1900 }
1901
1902 void SystemDictionary::methods_do(void f(Method*)) {
1903 // Walk methods in loaded classes
1904 ClassLoaderDataGraph::methods_do(f);
1905 // Walk method handle intrinsics
1906 invoke_method_table()->methods_do(f);
1907 }
1908
1909 class RemoveClassesClosure : public CLDClosure {
1910 public:
1911 void do_cld(ClassLoaderData* cld) {
1912 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1913 cld->dictionary()->remove_classes_in_error_state();
1914 }
1915 }
1916 };
1917
1918 void SystemDictionary::remove_classes_in_error_state() {
1919 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1920 RemoveClassesClosure rcc;
1921 ClassLoaderDataGraph::cld_do(&rcc);
1922 }
1923
1924 // ----------------------------------------------------------------------------
1925 // Initialization
1926
1927 void SystemDictionary::initialize(TRAPS) {
1928 // Allocate arrays
1929 _placeholders = new PlaceholderTable(_placeholder_table_size);
1930 _number_of_modifications = 0;
1931 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1932 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1933 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1934 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1935
1936 // Allocate private object used as system class loader lock
1937 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1938 // Initialize basic classes
1939 resolve_preloaded_classes(CHECK);
1940 }
1941
1942 // Compact table of directions on the initialization of klasses:
1943 static const short wk_init_info[] = {
1944 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1945 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1946 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1947 | (int)SystemDictionary::option ),
1948 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1949 #undef WK_KLASS_INIT_INFO
1950 0
1951 };
1952
1953 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) {
1954 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1955 int info = wk_init_info[id - FIRST_WKID];
1956 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1957 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1958 InstanceKlass** klassp = &_well_known_klasses[id];
1959
1960 bool must_load;
1961 #if INCLUDE_JVMCI
1962 if (EnableJVMCI) {
1963 // If JVMCI is enabled we require its classes to be found.
1964 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1965 } else
1966 #endif
1967 {
1968 must_load = (init_opt < SystemDictionary::Opt);
1969 }
1970
1971 if ((*klassp) == NULL) {
1972 Klass* k;
1973 if (must_load) {
1974 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
1975 } else {
1976 k = resolve_or_null(symbol, CHECK_0); // load optional klass
1977 }
1978 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
1979 }
1980 return ((*klassp) != NULL);
1981 }
1982
1983 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1984 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1985 for (int id = (int)start_id; id < (int)limit_id; id++) {
1986 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1987 int info = wk_init_info[id - FIRST_WKID];
1988 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1989 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1990
1991 resolve_wk_klass((WKID)id, opt, CHECK);
1992 }
1993
1994 // move the starting value forward to the limit:
1995 start_id = limit_id;
1996 }
1997
1998 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
1999 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2000
2001 // Create the ModuleEntry for java.base. This call needs to be done here,
2002 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2003 ClassLoader::classLoader_init2(CHECK);
2004
2005 // Preload commonly used klasses
2006 WKID scan = FIRST_WKID;
2007 // first do Object, then String, Class
2008 #if INCLUDE_CDS
2009 if (UseSharedSpaces) {
2010 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2011 // Initialize the constant pool for the Object_class
2012 Object_klass()->constants()->restore_unshareable_info(CHECK);
2013 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2014 } else
2015 #endif
2016 {
2017 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2018 }
2019
2020 // Calculate offsets for String and Class classes since they are loaded and
2021 // can be used after this point.
2022 java_lang_String::compute_offsets();
2023 java_lang_Class::compute_offsets();
2024
2025 // Fixup mirrors for classes loaded before java.lang.Class.
2026 // These calls iterate over the objects currently in the perm gen
2027 // so calling them at this point is matters (not before when there
2028 // are fewer objects and not later after there are more objects
2029 // in the perm gen.
2030 Universe::initialize_basic_type_mirrors(CHECK);
2031 Universe::fixup_mirrors(CHECK);
2032
2033 // do a bunch more:
2034 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2035
2036 // Preload ref klasses and set reference types
2037 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2038 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2039
2040 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2041 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2042 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2043 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2044 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2045
2046 // JSR 292 classes
2047 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2048 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2049 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2050 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2051 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2052
2053 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2054 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2055 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2056 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2057 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2058 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2059 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2060 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2061 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2062 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2063
2064 { // Compute whether we should use checkPackageAccess or NOT
2065 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2066 _has_checkPackageAccess = (method != NULL);
2067 }
2068 }
2069
2070 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2071 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2072 BasicType SystemDictionary::box_klass_type(Klass* k) {
2073 assert(k != NULL, "");
2074 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2075 if (_box_klasses[i] == k)
2076 return (BasicType)i;
2077 }
2078 return T_OBJECT;
2079 }
2080
2081 // Constraints on class loaders. The details of the algorithm can be
2082 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2083 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2084 // that the dictionary needs to maintain a set of contraints that
2085 // must be satisfied by all classes in the dictionary.
2086 // if defining is true, then LinkageError if already in dictionary
2087 // if initiating loader, then ok if InstanceKlass matches existing entry
2088
2089 void SystemDictionary::check_constraints(unsigned int d_hash,
2090 InstanceKlass* k,
2091 Handle class_loader,
2092 bool defining,
2093 TRAPS) {
2094 ResourceMark rm(THREAD);
2095 stringStream ss;
2096 bool throwException = false;
2097
2098 {
2099 Symbol *name = k->name();
2100 ClassLoaderData *loader_data = class_loader_data(class_loader);
2101
2102 MutexLocker mu(SystemDictionary_lock, THREAD);
2103
2104 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2105 if (check != NULL) {
2106 // If different InstanceKlass - duplicate class definition,
2107 // else - ok, class loaded by a different thread in parallel.
2108 // We should only have found it if it was done loading and ok to use.
2109 // The dictionary only holds instance classes, placeholders
2110 // also hold array classes.
2111
2112 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2113 if ((defining == true) || (k != check)) {
2114 throwException = true;
2115 ss.print("loader %s", loader_data->loader_name_and_id());
2116 ss.print(" attempted duplicate %s definition for %s. (%s)",
2117 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2118 } else {
2119 return;
2120 }
2121 }
2122
2123 #ifdef ASSERT
2124 Symbol* ph_check = find_placeholder(name, loader_data);
2125 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2126 #endif
2127
2128 if (throwException == false) {
2129 if (constraints()->check_or_update(k, class_loader, name) == false) {
2130 throwException = true;
2131 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2132 ss.print(" wants to load %s %s.",
2133 k->external_kind(), k->external_name());
2134 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2135 if (existing_klass->class_loader() != class_loader()) {
2136 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2137 existing_klass->external_kind(),
2138 existing_klass->class_loader_data()->loader_name_and_id(),
2139 existing_klass->class_in_module_of_loader(false, true));
2140 } else {
2141 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2142 }
2143 }
2144 }
2145 }
2146
2147 // Throw error now if needed (cannot throw while holding
2148 // SystemDictionary_lock because of rank ordering)
2149 if (throwException == true) {
2150 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2151 }
2152 }
2153
2154 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2155 // have been called.
2156 void SystemDictionary::update_dictionary(unsigned int d_hash,
2157 int p_index, unsigned int p_hash,
2158 InstanceKlass* k,
2159 Handle class_loader,
2160 TRAPS) {
2161 // Compile_lock prevents systemDictionary updates during compilations
2162 assert_locked_or_safepoint(Compile_lock);
2163 Symbol* name = k->name();
2164 ClassLoaderData *loader_data = class_loader_data(class_loader);
2165
2166 {
2167 MutexLocker mu1(SystemDictionary_lock, THREAD);
2168
2169 // See whether biased locking is enabled and if so set it for this
2170 // klass.
2171 // Note that this must be done past the last potential blocking
2172 // point / safepoint. We enable biased locking lazily using a
2173 // VM_Operation to iterate the SystemDictionary and installing the
2174 // biasable mark word into each InstanceKlass's prototype header.
2175 // To avoid race conditions where we accidentally miss enabling the
2176 // optimization for one class in the process of being added to the
2177 // dictionary, we must not safepoint after the test of
2178 // BiasedLocking::enabled().
2179 if (UseBiasedLocking && BiasedLocking::enabled()) {
2180 // Set biased locking bit for all loaded classes; it will be
2181 // cleared if revocation occurs too often for this type
2182 // NOTE that we must only do this when the class is initally
2183 // defined, not each time it is referenced from a new class loader
2184 if (oopDesc::equals(k->class_loader(), class_loader())) {
2185 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2186 }
2187 }
2188
2189 // Make a new dictionary entry.
2190 Dictionary* dictionary = loader_data->dictionary();
2191 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2192 if (sd_check == NULL) {
2193 dictionary->add_klass(d_hash, name, k);
2194 notice_modification();
2195 }
2196 #ifdef ASSERT
2197 sd_check = find_class(d_hash, name, dictionary);
2198 assert (sd_check != NULL, "should have entry in dictionary");
2199 // Note: there may be a placeholder entry: for circularity testing
2200 // or for parallel defines
2201 #endif
2202 SystemDictionary_lock->notify_all();
2203 }
2204 }
2205
2206
2207 // Try to find a class name using the loader constraints. The
2208 // loader constraints might know about a class that isn't fully loaded
2209 // yet and these will be ignored.
2210 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2211 Symbol* class_name, Handle class_loader, TRAPS) {
2212
2213 // First see if it has been loaded directly.
2214 // Force the protection domain to be null. (This removes protection checks.)
2215 Handle no_protection_domain;
2216 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2217 no_protection_domain, CHECK_NULL);
2218 if (klass != NULL)
2219 return klass;
2220
2221 // Now look to see if it has been loaded elsewhere, and is subject to
2222 // a loader constraint that would require this loader to return the
2223 // klass that is already loaded.
2224 if (FieldType::is_array(class_name)) {
2225 // For array classes, their Klass*s are not kept in the
2226 // constraint table. The element Klass*s are.
2227 FieldArrayInfo fd;
2228 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2229 if (t != T_OBJECT) {
2230 klass = Universe::typeArrayKlassObj(t);
2231 } else {
2232 MutexLocker mu(SystemDictionary_lock, THREAD);
2233 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2234 }
2235 // If element class already loaded, allocate array klass
2236 if (klass != NULL) {
2237 klass = klass->array_klass_or_null(fd.dimension());
2238 }
2239 } else {
2240 MutexLocker mu(SystemDictionary_lock, THREAD);
2241 // Non-array classes are easy: simply check the constraint table.
2242 klass = constraints()->find_constrained_klass(class_name, class_loader);
2243 }
2244
2245 return klass;
2246 }
2247
2248
2249 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2250 Handle class_loader1,
2251 Handle class_loader2,
2252 Thread* THREAD) {
2253 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2254 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2255
2256 Symbol* constraint_name = NULL;
2257 // Needs to be in same scope as constraint_name in case a Symbol is created and
2258 // assigned to constraint_name.
2259 FieldArrayInfo fd;
2260 if (!FieldType::is_array(class_name)) {
2261 constraint_name = class_name;
2262 } else {
2263 // For array classes, their Klass*s are not kept in the
2264 // constraint table. The element classes are.
2265 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2266 // primitive types always pass
2267 if (t != T_OBJECT) {
2268 return true;
2269 } else {
2270 constraint_name = fd.object_key();
2271 }
2272 }
2273
2274 Dictionary* dictionary1 = loader_data1->dictionary();
2275 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2276
2277 Dictionary* dictionary2 = loader_data2->dictionary();
2278 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2279
2280 {
2281 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2282 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2283 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2284 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2285 klass2, class_loader2);
2286 }
2287 }
2288
2289 // Add entry to resolution error table to record the error when the first
2290 // attempt to resolve a reference to a class has failed.
2291 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2292 Symbol* error, Symbol* message) {
2293 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2294 int index = resolution_errors()->hash_to_index(hash);
2295 {
2296 MutexLocker ml(SystemDictionary_lock, Thread::current());
2297 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2298 }
2299 }
2300
2301 // Delete a resolution error for RedefineClasses for a constant pool is going away
2302 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2303 resolution_errors()->delete_entry(pool);
2304 }
2305
2306 // Lookup resolution error table. Returns error if found, otherwise NULL.
2307 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2308 Symbol** message) {
2309 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2310 int index = resolution_errors()->hash_to_index(hash);
2311 {
2312 MutexLocker ml(SystemDictionary_lock, Thread::current());
2313 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2314 if (entry != NULL) {
2315 *message = entry->message();
2316 return entry->error();
2317 } else {
2318 return NULL;
2319 }
2320 }
2321 }
2322
2323
2324 // Signature constraints ensure that callers and callees agree about
2325 // the meaning of type names in their signatures. This routine is the
2326 // intake for constraints. It collects them from several places:
2327 //
2328 // * LinkResolver::resolve_method (if check_access is true) requires
2329 // that the resolving class (the caller) and the defining class of
2330 // the resolved method (the callee) agree on each type in the
2331 // method's signature.
2332 //
2333 // * LinkResolver::resolve_interface_method performs exactly the same
2334 // checks.
2335 //
2336 // * LinkResolver::resolve_field requires that the constant pool
2337 // attempting to link to a field agree with the field's defining
2338 // class about the type of the field signature.
2339 //
2340 // * klassVtable::initialize_vtable requires that, when a class
2341 // overrides a vtable entry allocated by a superclass, that the
2342 // overriding method (i.e., the callee) agree with the superclass
2343 // on each type in the method's signature.
2344 //
2345 // * klassItable::initialize_itable requires that, when a class fills
2346 // in its itables, for each non-abstract method installed in an
2347 // itable, the method (i.e., the callee) agree with the interface
2348 // on each type in the method's signature.
2349 //
2350 // All those methods have a boolean (check_access, checkconstraints)
2351 // which turns off the checks. This is used from specialized contexts
2352 // such as bootstrapping, dumping, and debugging.
2353 //
2354 // No direct constraint is placed between the class and its
2355 // supertypes. Constraints are only placed along linked relations
2356 // between callers and callees. When a method overrides or implements
2357 // an abstract method in a supertype (superclass or interface), the
2358 // constraints are placed as if the supertype were the caller to the
2359 // overriding method. (This works well, since callers to the
2360 // supertype have already established agreement between themselves and
2361 // the supertype.) As a result of all this, a class can disagree with
2362 // its supertype about the meaning of a type name, as long as that
2363 // class neither calls a relevant method of the supertype, nor is
2364 // called (perhaps via an override) from the supertype.
2365 //
2366 //
2367 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2368 //
2369 // Make sure all class components (including arrays) in the given
2370 // signature will be resolved to the same class in both loaders.
2371 // Returns the name of the type that failed a loader constraint check, or
2372 // NULL if no constraint failed. No exception except OOME is thrown.
2373 // Arrays are not added to the loader constraint table, their elements are.
2374 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2375 Handle loader1, Handle loader2,
2376 bool is_method, TRAPS) {
2377 // Nothing to do if loaders are the same.
2378 if (oopDesc::equals(loader1(), loader2())) {
2379 return NULL;
2380 }
2381
2382 SignatureStream sig_strm(signature, is_method);
2383 while (!sig_strm.is_done()) {
2384 if (sig_strm.is_object()) {
2385 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2386 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2387 return sig;
2388 }
2389 }
2390 sig_strm.next();
2391 }
2392 return NULL;
2393 }
2394
2395
2396 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2397 Symbol* signature,
2398 TRAPS) {
2399 methodHandle empty;
2400 assert(MethodHandles::is_signature_polymorphic(iid) &&
2401 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2402 iid != vmIntrinsics::_invokeGeneric,
2403 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2404
2405 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2406 int index = invoke_method_table()->hash_to_index(hash);
2407 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2408 methodHandle m;
2409 if (spe == NULL || spe->method() == NULL) {
2410 spe = NULL;
2411 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2412 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2413 if (!Arguments::is_interpreter_only()) {
2414 // Generate a compiled form of the MH intrinsic.
2415 AdapterHandlerLibrary::create_native_wrapper(m);
2416 // Check if have the compiled code.
2417 if (!m->has_compiled_code()) {
2418 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2419 "Out of space in CodeCache for method handle intrinsic", empty);
2420 }
2421 }
2422 // Now grab the lock. We might have to throw away the new method,
2423 // if a racing thread has managed to install one at the same time.
2424 {
2425 MutexLocker ml(SystemDictionary_lock, THREAD);
2426 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2427 if (spe == NULL)
2428 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2429 if (spe->method() == NULL)
2430 spe->set_method(m());
2431 }
2432 }
2433
2434 assert(spe != NULL && spe->method() != NULL, "");
2435 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2436 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2437 "MH intrinsic invariant");
2438 return spe->method();
2439 }
2440
2441 // Helper for unpacking the return value from linkMethod and linkCallSite.
2442 static methodHandle unpack_method_and_appendix(Handle mname,
2443 Klass* accessing_klass,
2444 objArrayHandle appendix_box,
2445 Handle* appendix_result,
2446 TRAPS) {
2447 methodHandle empty;
2448 if (mname.not_null()) {
2449 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2450 if (m != NULL) {
2451 oop appendix = appendix_box->obj_at(0);
2452 if (TraceMethodHandles) {
2453 #ifndef PRODUCT
2454 ttyLocker ttyl;
2455 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2456 m->print();
2457 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2458 tty->cr();
2459 #endif //PRODUCT
2460 }
2461 (*appendix_result) = Handle(THREAD, appendix);
2462 // the target is stored in the cpCache and if a reference to this
2463 // MemberName is dropped we need a way to make sure the
2464 // class_loader containing this method is kept alive.
2465 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2466 this_key->record_dependency(m->method_holder());
2467 return methodHandle(THREAD, m);
2468 }
2469 }
2470 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2471 return empty;
2472 }
2473
2474 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2475 Symbol* name,
2476 Symbol* signature,
2477 Klass* accessing_klass,
2478 Handle *appendix_result,
2479 Handle *method_type_result,
2480 TRAPS) {
2481 methodHandle empty;
2482 assert(THREAD->can_call_java() ,"");
2483 Handle method_type =
2484 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2485
2486 int ref_kind = JVM_REF_invokeVirtual;
2487 oop name_oop = StringTable::intern(name, CHECK_(empty));
2488 Handle name_str (THREAD, name_oop);
2489 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2490 assert(appendix_box->obj_at(0) == NULL, "");
2491
2492 // This should not happen. JDK code should take care of that.
2493 if (accessing_klass == NULL || method_type.is_null()) {
2494 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2495 }
2496
2497 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2498 JavaCallArguments args;
2499 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2500 args.push_int(ref_kind);
2501 args.push_oop(Handle(THREAD, klass->java_mirror()));
2502 args.push_oop(name_str);
2503 args.push_oop(method_type);
2504 args.push_oop(appendix_box);
2505 JavaValue result(T_OBJECT);
2506 JavaCalls::call_static(&result,
2507 SystemDictionary::MethodHandleNatives_klass(),
2508 vmSymbols::linkMethod_name(),
2509 vmSymbols::linkMethod_signature(),
2510 &args, CHECK_(empty));
2511 Handle mname(THREAD, (oop) result.get_jobject());
2512 (*method_type_result) = method_type;
2513 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2514 }
2515
2516 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2517 // We must ensure that all class loaders everywhere will reach this class, for any client.
2518 // This is a safe bet for public classes in java.lang, such as Object and String.
2519 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2520 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2521 static bool is_always_visible_class(oop mirror) {
2522 Klass* klass = java_lang_Class::as_Klass(mirror);
2523 if (klass->is_objArray_klass()) {
2524 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2525 }
2526 if (klass->is_typeArray_klass()) {
2527 return true; // primitive array
2528 }
2529 assert(klass->is_instance_klass(), "%s", klass->external_name());
2530 return klass->is_public() &&
2531 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2532 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2533 }
2534
2535
2536 // Return the Java mirror (java.lang.Class instance) for a single-character
2537 // descriptor. This result, when available, is the same as produced by the
2538 // heavier API point of the same name that takes a Symbol.
2539 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2540 return java_lang_Class::primitive_mirror(char2type(signature_char));
2541 }
2542
2543 // Find or construct the Java mirror (java.lang.Class instance) for a
2544 // for the given field type signature, as interpreted relative to the
2545 // given class loader. Handles primitives, void, references, arrays,
2546 // and all other reflectable types, except method types.
2547 // N.B. Code in reflection should use this entry point.
2548 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2549 Klass* accessing_klass,
2550 Handle class_loader,
2551 Handle protection_domain,
2552 SignatureStream::FailureMode failure_mode,
2553 TRAPS) {
2554 Handle empty;
2555
2556 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2557 "one or the other, or perhaps neither");
2558
2559 Symbol* type = signature;
2560
2561 // What we have here must be a valid field descriptor,
2562 // and all valid field descriptors are supported.
2563 // Produce the same java.lang.Class that reflection reports.
2564 if (type->utf8_length() == 1) {
2565
2566 // It's a primitive. (Void has a primitive mirror too.)
2567 char ch = (char) type->byte_at(0);
2568 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2569 return Handle(THREAD, find_java_mirror_for_type(ch));
2570
2571 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2572
2573 // It's a reference type.
2574 if (accessing_klass != NULL) {
2575 class_loader = Handle(THREAD, accessing_klass->class_loader());
2576 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2577 }
2578 Klass* constant_type_klass;
2579 if (failure_mode == SignatureStream::ReturnNull) {
2580 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2581 CHECK_(empty));
2582 } else {
2583 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2584 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2585 throw_error, CHECK_(empty));
2586 }
2587 if (constant_type_klass == NULL) {
2588 return Handle(); // report failure this way
2589 }
2590 Handle mirror(THREAD, constant_type_klass->java_mirror());
2591
2592 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2593 if (accessing_klass != NULL) {
2594 Klass* sel_klass = constant_type_klass;
2595 bool fold_type_to_class = true;
2596 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2597 fold_type_to_class, CHECK_(empty));
2598 }
2599
2600 return mirror;
2601
2602 }
2603
2604 // Fall through to an error.
2605 assert(false, "unsupported mirror syntax");
2606 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2607 }
2608
2609
2610 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2611 // signature, as interpreted relative to the given class loader.
2612 // Because of class loader constraints, all method handle usage must be
2613 // consistent with this loader.
2614 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2615 Klass* accessing_klass,
2616 TRAPS) {
2617 Handle empty;
2618 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2619 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2620 int index = invoke_method_table()->hash_to_index(hash);
2621 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2622 if (spe != NULL && spe->method_type() != NULL) {
2623 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2624 return Handle(THREAD, spe->method_type());
2625 } else if (!THREAD->can_call_java()) {
2626 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2627 return Handle(); // do not attempt from within compiler, unless it was cached
2628 }
2629
2630 Handle class_loader, protection_domain;
2631 if (accessing_klass != NULL) {
2632 class_loader = Handle(THREAD, accessing_klass->class_loader());
2633 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2634 }
2635 bool can_be_cached = true;
2636 int npts = ArgumentCount(signature).size();
2637 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2638 int arg = 0;
2639 Handle rt; // the return type from the signature
2640 ResourceMark rm(THREAD);
2641 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2642 oop mirror = NULL;
2643 if (can_be_cached) {
2644 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2645 mirror = ss.as_java_mirror(Handle(), Handle(),
2646 SignatureStream::ReturnNull, CHECK_(empty));
2647 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2648 // Fall back to accessing_klass context.
2649 can_be_cached = false;
2650 }
2651 }
2652 if (!can_be_cached) {
2653 // Resolve, throwing a real error if it doesn't work.
2654 mirror = ss.as_java_mirror(class_loader, protection_domain,
2655 SignatureStream::NCDFError, CHECK_(empty));
2656 }
2657 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2658 if (ss.at_return_type())
2659 rt = Handle(THREAD, mirror);
2660 else
2661 pts->obj_at_put(arg++, mirror);
2662
2663 // Check accessibility.
2664 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2665 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2666 mirror = NULL; // safety
2667 // Emulate ConstantPool::verify_constant_pool_resolve.
2668 bool fold_type_to_class = true;
2669 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2670 fold_type_to_class, CHECK_(empty));
2671 }
2672 }
2673 assert(arg == npts, "");
2674
2675 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2676 JavaCallArguments args(Handle(THREAD, rt()));
2677 args.push_oop(pts);
2678 JavaValue result(T_OBJECT);
2679 JavaCalls::call_static(&result,
2680 SystemDictionary::MethodHandleNatives_klass(),
2681 vmSymbols::findMethodHandleType_name(),
2682 vmSymbols::findMethodHandleType_signature(),
2683 &args, CHECK_(empty));
2684 Handle method_type(THREAD, (oop) result.get_jobject());
2685
2686 if (can_be_cached) {
2687 // We can cache this MethodType inside the JVM.
2688 MutexLocker ml(SystemDictionary_lock, THREAD);
2689 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2690 if (spe == NULL)
2691 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2692 if (spe->method_type() == NULL) {
2693 spe->set_method_type(method_type());
2694 }
2695 }
2696
2697 // report back to the caller with the MethodType
2698 return method_type;
2699 }
2700
2701 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2702 Klass* accessing_klass,
2703 TRAPS) {
2704 Handle empty;
2705 ResourceMark rm(THREAD);
2706 SignatureStream ss(signature, /*is_method=*/ false);
2707 if (!ss.is_done()) {
2708 Handle class_loader, protection_domain;
2709 if (accessing_klass != NULL) {
2710 class_loader = Handle(THREAD, accessing_klass->class_loader());
2711 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2712 }
2713 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2714 ss.next();
2715 if (ss.is_done()) {
2716 return Handle(THREAD, mirror);
2717 }
2718 }
2719 return empty;
2720 }
2721
2722 // Ask Java code to find or construct a method handle constant.
2723 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2724 int ref_kind, //e.g., JVM_REF_invokeVirtual
2725 Klass* callee,
2726 Symbol* name,
2727 Symbol* signature,
2728 TRAPS) {
2729 Handle empty;
2730 if (caller == NULL) {
2731 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2732 }
2733 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2734 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2735
2736 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2737 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2738 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2739 java_lang_invoke_MemberName::set_name (mname(), name_str());
2740 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2741 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2742
2743 if (ref_kind == JVM_REF_invokeVirtual &&
2744 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2745 // Skip resolution for public signature polymorphic methods such as
2746 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2747 // They require appendix argument which MemberName resolution doesn't handle.
2748 // There's special logic on JDK side to handle them
2749 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2750 } else {
2751 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2752 }
2753
2754 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2755 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2756
2757 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2758 JavaCallArguments args;
2759 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2760 args.push_int(ref_kind);
2761 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2762 args.push_oop(name_str);
2763 args.push_oop(type);
2764 JavaValue result(T_OBJECT);
2765 JavaCalls::call_static(&result,
2766 SystemDictionary::MethodHandleNatives_klass(),
2767 vmSymbols::linkMethodHandleConstant_name(),
2768 vmSymbols::linkMethodHandleConstant_signature(),
2769 &args, CHECK_(empty));
2770 return Handle(THREAD, (oop) result.get_jobject());
2771 }
2772
2773 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2774 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2775 int condy_index,
2776 Handle bootstrap_specifier,
2777 Symbol* name,
2778 Symbol* type,
2779 TRAPS) {
2780 Handle empty;
2781 Handle bsm, info;
2782 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2783 bsm = bootstrap_specifier;
2784 } else {
2785 assert(bootstrap_specifier->is_objArray(), "");
2786 objArrayOop args = (objArrayOop) bootstrap_specifier();
2787 assert(args->length() == 2, "");
2788 bsm = Handle(THREAD, args->obj_at(0));
2789 info = Handle(THREAD, args->obj_at(1));
2790 }
2791 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2792 "caller must supply a valid BSM");
2793
2794 // This should not happen. JDK code should take care of that.
2795 if (caller == NULL) {
2796 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2797 }
2798
2799 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2800
2801 // Resolve the constant type in the context of the caller class
2802 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2803 CHECK_(empty));
2804
2805 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2806 JavaCallArguments args;
2807 args.push_oop(Handle(THREAD, caller->java_mirror()));
2808 args.push_int(condy_index);
2809 args.push_oop(bsm);
2810 args.push_oop(constant_name);
2811 args.push_oop(type_mirror);
2812 args.push_oop(info);
2813 JavaValue result(T_OBJECT);
2814 JavaCalls::call_static(&result,
2815 SystemDictionary::MethodHandleNatives_klass(),
2816 vmSymbols::linkDynamicConstant_name(),
2817 vmSymbols::linkDynamicConstant_signature(),
2818 &args, CHECK_(empty));
2819
2820 return Handle(THREAD, (oop) result.get_jobject());
2821 }
2822
2823 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2824 // name and signature, as interpreted relative to the given class loader.
2825 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2826 int indy_index,
2827 Handle bootstrap_specifier,
2828 Symbol* name,
2829 Symbol* type,
2830 Handle *appendix_result,
2831 Handle *method_type_result,
2832 TRAPS) {
2833 methodHandle empty;
2834 Handle bsm, info;
2835 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2836 bsm = bootstrap_specifier;
2837 } else {
2838 objArrayOop args = (objArrayOop) bootstrap_specifier();
2839 assert(args->length() == 2, "");
2840 bsm = Handle(THREAD, args->obj_at(0));
2841 info = Handle(THREAD, args->obj_at(1));
2842 }
2843 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2844 "caller must supply a valid BSM");
2845
2846 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2847 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2848
2849 // This should not happen. JDK code should take care of that.
2850 if (caller == NULL || method_type.is_null()) {
2851 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2852 }
2853
2854 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2855 assert(appendix_box->obj_at(0) == NULL, "");
2856
2857 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2858 JavaCallArguments args;
2859 args.push_oop(Handle(THREAD, caller->java_mirror()));
2860 args.push_int(indy_index);
2861 args.push_oop(bsm);
2862 args.push_oop(method_name);
2863 args.push_oop(method_type);
2864 args.push_oop(info);
2865 args.push_oop(appendix_box);
2866 JavaValue result(T_OBJECT);
2867 JavaCalls::call_static(&result,
2868 SystemDictionary::MethodHandleNatives_klass(),
2869 vmSymbols::linkCallSite_name(),
2870 vmSymbols::linkCallSite_signature(),
2871 &args, CHECK_(empty));
2872 Handle mname(THREAD, (oop) result.get_jobject());
2873 (*method_type_result) = method_type;
2874 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2875 }
2876
2877 // Protection domain cache table handling
2878
2879 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2880 return _pd_cache_table->get(protection_domain);
2881 }
2882
2883 #if INCLUDE_CDS
2884 void SystemDictionary::reorder_dictionary_for_sharing() {
2885 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2886 }
2887 #endif
2888
2889 size_t SystemDictionary::count_bytes_for_buckets() {
2890 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2891 }
2892
2893 size_t SystemDictionary::count_bytes_for_table() {
2894 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2895 }
2896
2897 void SystemDictionary::copy_buckets(char* top, char* end) {
2898 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2899 }
2900
2901 void SystemDictionary::copy_table(char* top, char* end) {
2902 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2903 }
2904
2905 // ----------------------------------------------------------------------------
2906 void SystemDictionary::print_shared(outputStream *st) {
2907 shared_dictionary()->print_on(st);
2908 }
2909
2910 void SystemDictionary::print_on(outputStream *st) {
2911 if (shared_dictionary() != NULL) {
2912 st->print_cr("Shared Dictionary");
2913 shared_dictionary()->print_on(st);
2914 st->cr();
2915 }
2916
2917 GCMutexLocker mu(SystemDictionary_lock);
2918
2919 ClassLoaderDataGraph::print_dictionary(st);
2920
2921 // Placeholders
2922 placeholders()->print_on(st);
2923 st->cr();
2924
2925 // loader constraints - print under SD_lock
2926 constraints()->print_on(st);
2927 st->cr();
2928
2929 _pd_cache_table->print_on(st);
2930 st->cr();
2931 }
2932
2933 void SystemDictionary::verify() {
2934 guarantee(constraints() != NULL,
2935 "Verify of loader constraints failed");
2936 guarantee(placeholders()->number_of_entries() >= 0,
2937 "Verify of placeholders failed");
2938
2939 GCMutexLocker mu(SystemDictionary_lock);
2940
2941 // Verify dictionary
2942 ClassLoaderDataGraph::verify_dictionary();
2943
2944 placeholders()->verify();
2945
2946 // Verify constraint table
2947 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2948 constraints()->verify(placeholders());
2949
2950 _pd_cache_table->verify();
2951 }
2952
2953 void SystemDictionary::dump(outputStream *st, bool verbose) {
2954 assert_locked_or_safepoint(SystemDictionary_lock);
2955 if (verbose) {
2956 print_on(st);
2957 } else {
2958 if (shared_dictionary() != NULL) {
2959 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2960 }
2961 ClassLoaderDataGraph::print_dictionary_statistics(st);
2962 placeholders()->print_table_statistics(st, "Placeholder Table");
2963 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2964 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2965 }
2966 }
2967
2968 // Utility for dumping dictionaries.
2969 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2970 DCmdWithParser(output, heap),
2971 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2972 "BOOLEAN", false, "false") {
2973 _dcmdparser.add_dcmd_option(&_verbose);
2974 }
2975
2976 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2977 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2978 _verbose.value());
2979 VMThread::execute(&dumper);
2980 }
2981
2982 int SystemDictionaryDCmd::num_arguments() {
2983 ResourceMark rm;
2984 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2985 if (dcmd != NULL) {
2986 DCmdMark mark(dcmd);
2987 return dcmd->_dcmdparser.num_arguments();
2988 } else {
2989 return 0;
2990 }
2991 }
2992
2993 class CombineDictionariesClosure : public CLDClosure {
2994 private:
2995 Dictionary* _master_dictionary;
2996 public:
2997 CombineDictionariesClosure(Dictionary* master_dictionary) :
2998 _master_dictionary(master_dictionary) {}
2999 void do_cld(ClassLoaderData* cld) {
3000 ResourceMark rm;
3001 if (cld->is_anonymous()) {
3002 return;
3003 }
3004 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3005 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3006 Dictionary* curr_dictionary = cld->dictionary();
3007 DictionaryEntry* p = curr_dictionary->bucket(i);
3008 while (p != NULL) {
3009 Symbol* name = p->instance_klass()->name();
3010 unsigned int d_hash = _master_dictionary->compute_hash(name);
3011 int d_index = _master_dictionary->hash_to_index(d_hash);
3012 DictionaryEntry* next = p->next();
3013 if (p->literal()->class_loader_data() != cld) {
3014 // This is an initiating class loader entry; don't use it
3015 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3016 curr_dictionary->free_entry(p);
3017 } else {
3018 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3019 curr_dictionary->unlink_entry(p);
3020 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3021 _master_dictionary->add_entry(d_index, p);
3022 }
3023 p = next;
3024 }
3025 *curr_dictionary->bucket_addr(i) = NULL;
3026 }
3027 }
3028 }
3029 };
3030
3031 // Combining platform and system loader dictionaries into boot loader dictionary.
3032 // During run time, we only have one shared dictionary.
3033 void SystemDictionary::combine_shared_dictionaries() {
3034 assert(DumpSharedSpaces, "dump time only");
3035 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3036 CombineDictionariesClosure cdc(master_dictionary);
3037 ClassLoaderDataGraph::cld_do(&cdc);
3038
3039 // These tables are no longer valid or necessary. Keeping them around will
3040 // cause SystemDictionary::verify() to fail. Let's empty them.
3041 _placeholders = new PlaceholderTable(_placeholder_table_size);
3042 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3043
3044 NOT_PRODUCT(SystemDictionary::verify());
3045 }
3046
3047 void SystemDictionary::initialize_oop_storage() {
3048 _vm_weak_oop_storage =
3049 new OopStorage("VM Weak Oop Handles",
3050 VMWeakAlloc_lock,
3051 VMWeakActive_lock);
3052 }
3053
3054 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3055 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3056 return _vm_weak_oop_storage;
3057 }