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 #if INCLUDE_JFR
93 #include "jfr/jfr.hpp"
94 #endif
95
96 PlaceholderTable* SystemDictionary::_placeholders = NULL;
97 Dictionary* SystemDictionary::_shared_dictionary = NULL;
98 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
99 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
100 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
101 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
102
103 int SystemDictionary::_number_of_modifications = 0;
104 oop SystemDictionary::_system_loader_lock_obj = NULL;
105
106 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
107 = { NULL /*, NULL...*/ };
108
109 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
110
111 oop SystemDictionary::_java_system_loader = NULL;
112 oop SystemDictionary::_java_platform_loader = NULL;
113
114 bool SystemDictionary::_has_checkPackageAccess = false;
115
116 // Default ProtectionDomainCacheSize value
117
118 const int defaultProtectionDomainCacheSize = 1009;
119
120 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
121
122
123 // ----------------------------------------------------------------------------
124 // Java-level SystemLoader and PlatformLoader
125
126 oop SystemDictionary::java_system_loader() {
127 return _java_system_loader;
128 }
129
130 oop SystemDictionary::java_platform_loader() {
131 return _java_platform_loader;
132 }
133
134 void SystemDictionary::compute_java_loaders(TRAPS) {
135 JavaValue result(T_OBJECT);
136 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
137 JavaCalls::call_static(&result,
138 class_loader_klass,
139 vmSymbols::getSystemClassLoader_name(),
140 vmSymbols::void_classloader_signature(),
141 CHECK);
142
143 _java_system_loader = (oop)result.get_jobject();
144
145 JavaCalls::call_static(&result,
146 class_loader_klass,
147 vmSymbols::getPlatformClassLoader_name(),
148 vmSymbols::void_classloader_signature(),
149 CHECK);
150
151 _java_platform_loader = (oop)result.get_jobject();
152 }
153
154 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
155 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
156 return ClassLoaderDataGraph::find_or_create(class_loader);
157 }
158
159 // ----------------------------------------------------------------------------
160 // Parallel class loading check
161
162 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
163 if (class_loader.is_null()) return true;
164 if (AlwaysLockClassLoader) return false;
165 return java_lang_ClassLoader::parallelCapable(class_loader());
166 }
167 // ----------------------------------------------------------------------------
168 // ParallelDefineClass flag does not apply to bootclass loader
169 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
170 if (class_loader.is_null()) return false;
171 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
172 return true;
173 }
174 return false;
175 }
176
177 // Returns true if the passed class loader is the builtin application class loader
178 // or a custom system class loader. A customer system class loader can be
179 // specified via -Djava.system.class.loader.
180 bool SystemDictionary::is_system_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
185 oopDesc::equals(class_loader, _java_system_loader));
186 }
187
188 // Returns true if the passed class loader is the platform class loader.
189 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
190 if (class_loader == NULL) {
191 return false;
192 }
193 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
194 }
195
196 // ----------------------------------------------------------------------------
197 // Resolving of classes
198
199 // Forwards to resolve_or_null
200
201 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
202 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
203 if (HAS_PENDING_EXCEPTION || klass == NULL) {
204 // can return a null klass
205 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
206 }
207 return klass;
208 }
209
210 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
211 bool throw_error,
212 Klass* klass, TRAPS) {
213 if (HAS_PENDING_EXCEPTION) {
214 // If we have a pending exception we forward it to the caller, unless throw_error is true,
215 // in which case we have to check whether the pending exception is a ClassNotFoundException,
216 // and if so convert it to a NoClassDefFoundError
217 // And chain the original ClassNotFoundException
218 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
219 ResourceMark rm(THREAD);
220 assert(klass == NULL, "Should not have result with exception pending");
221 Handle e(THREAD, PENDING_EXCEPTION);
222 CLEAR_PENDING_EXCEPTION;
223 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
224 } else {
225 return NULL;
226 }
227 }
228 // Class not found, throw appropriate error or exception depending on value of throw_error
229 if (klass == NULL) {
230 ResourceMark rm(THREAD);
231 if (throw_error) {
232 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
233 } else {
234 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
235 }
236 }
237 return klass;
238 }
239
240
241 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
242 bool throw_error, TRAPS)
243 {
244 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
245 }
246
247
248 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
249
250 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
251 if (FieldType::is_array(class_name)) {
252 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
253 } else {
254 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
255 }
256 }
257
258 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
259 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
260 Handle class_loader,
261 Handle protection_domain,
262 TRAPS) {
263 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
264 if (FieldType::is_obj(class_name)) {
265 ResourceMark rm(THREAD);
266 // Ignore wrapping L and ;.
267 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
268 class_name->utf8_length() - 2, CHECK_NULL);
269 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
270 } else {
271 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
272 }
273 }
274
275 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
276 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
277 }
278
279 // Forwards to resolve_instance_class_or_null
280
281 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
282 Handle class_loader,
283 Handle protection_domain,
284 TRAPS) {
285 assert(FieldType::is_array(class_name), "must be array");
286 Klass* k = NULL;
287 FieldArrayInfo fd;
288 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
289 // of this call
290 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
291 if (t == T_OBJECT) {
292 // naked oop "k" is OK here -- we assign back into it
293 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
294 class_loader,
295 protection_domain,
296 CHECK_NULL);
297 if (k != NULL) {
298 k = k->array_klass(fd.dimension(), CHECK_NULL);
299 }
300 } else {
301 k = Universe::typeArrayKlassObj(t);
302 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
303 }
304 return k;
305 }
306
307
308 // Must be called for any super-class or super-interface resolution
309 // during class definition to allow class circularity checking
310 // super-interface callers:
311 // parse_interfaces - for defineClass & jvmtiRedefineClasses
312 // super-class callers:
313 // ClassFileParser - for defineClass & jvmtiRedefineClasses
314 // load_shared_class - while loading a class from shared archive
315 // resolve_instance_class_or_null:
316 // via: handle_parallel_super_load
317 // when resolving a class that has an existing placeholder with
318 // a saved superclass [i.e. a defineClass is currently in progress]
319 // if another thread is trying to resolve the class, it must do
320 // super-class checks on its own thread to catch class circularity
321 // This last call is critical in class circularity checking for cases
322 // where classloading is delegated to different threads and the
323 // classloader lock is released.
324 // Take the case: Base->Super->Base
325 // 1. If thread T1 tries to do a defineClass of class Base
326 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
327 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
328 // so it tries to load Super
329 // 3. If we load the class internally, or user classloader uses same thread
330 // loadClassFromxxx or defineClass via parseClassFile Super ...
331 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
332 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
333 // 3.4 calls resolve_super_or_fail Base
334 // 3.5 finds T1,Base -> throws class circularity
335 //OR 4. If T2 tries to resolve Super via defineClass Super ...
336 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
337 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
338 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
339 // 4.4 finds T2, Super -> throws class circularity
340 // Must be called, even if superclass is null, since this is
341 // where the placeholder entry is created which claims this
342 // thread is loading this class/classloader.
343 // Be careful when modifying this code: once you have run
344 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
345 // you need to find_and_remove it before returning.
346 // So be careful to not exit with a CHECK_ macro betweeen these calls.
347 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
348 Symbol* super_name,
349 Handle class_loader,
350 Handle protection_domain,
351 bool is_superclass,
352 TRAPS) {
353 assert(!FieldType::is_array(super_name), "invalid super class name");
354 #if INCLUDE_CDS
355 if (DumpSharedSpaces) {
356 // Special processing for CDS dump time.
357 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
358 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
359 if (k) {
360 return k;
361 }
362 }
363 #endif // INCLUDE_CDS
364
365 // Double-check, if child class is already loaded, just return super-class,interface
366 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
367 // dictionary.
368 // Make sure there's a placeholder for the *child* before resolving.
369 // Used as a claim that this thread is currently loading superclass/classloader
370 // Used here for ClassCircularity checks and also for heap verification
371 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
372 // Must check ClassCircularity before checking if super class is already loaded.
373 //
374 // We might not already have a placeholder if this child_name was
375 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
376 // the name of the class might not be known until the stream is actually
377 // parsed.
378 // Bugs 4643874, 4715493
379
380 ClassLoaderData* loader_data = class_loader_data(class_loader);
381 Dictionary* dictionary = loader_data->dictionary();
382 unsigned int d_hash = dictionary->compute_hash(child_name);
383 unsigned int p_hash = placeholders()->compute_hash(child_name);
384 int p_index = placeholders()->hash_to_index(p_hash);
385 // can't throw error holding a lock
386 bool child_already_loaded = false;
387 bool throw_circularity_error = false;
388 {
389 MutexLocker mu(SystemDictionary_lock, THREAD);
390 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
391 InstanceKlass* quicksuperk;
392 // to support // loading: if child done loading, just return superclass
393 // if super_name, & class_loader don't match:
394 // if initial define, SD update will give LinkageError
395 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
396 // so we don't throw an exception here.
397 // see: nsk redefclass014 & java.lang.instrument Instrument032
398 if ((childk != NULL ) && (is_superclass) &&
399 ((quicksuperk = childk->java_super()) != NULL) &&
400 ((quicksuperk->name() == super_name) &&
401 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
402 return quicksuperk;
403 } else {
404 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
405 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
406 throw_circularity_error = true;
407 }
408 }
409 if (!throw_circularity_error) {
410 // Be careful not to exit resolve_super
411 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
412 }
413 }
414 if (throw_circularity_error) {
415 ResourceMark rm(THREAD);
416 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
417 }
418
419 // java.lang.Object should have been found above
420 assert(super_name != NULL, "null super class for resolving");
421 // Resolve the super class or interface, check results on return
422 InstanceKlass* superk =
423 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
424 class_loader,
425 protection_domain,
426 THREAD);
427
428 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
429 // It is no longer necessary to keep the placeholder table alive until update_dictionary
430 // or error. GC used to walk the placeholder table as strong roots.
431 // The instanceKlass is kept alive because the class loader is on the stack,
432 // which keeps the loader_data alive, as well as all instanceKlasses in
433 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
434 {
435 MutexLocker mu(SystemDictionary_lock, THREAD);
436 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
437 SystemDictionary_lock->notify_all();
438 }
439 if (HAS_PENDING_EXCEPTION || superk == NULL) {
440 // can null superk
441 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
442 assert(k == NULL || k == superk, "must be");
443 if (k == NULL) {
444 superk = NULL;
445 }
446 }
447
448 return superk;
449 }
450
451 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
452 Handle class_loader,
453 Handle protection_domain,
454 TRAPS) {
455 if(!has_checkPackageAccess()) return;
456
457 // Now we have to call back to java to check if the initating class has access
458 JavaValue result(T_VOID);
459 LogTarget(Debug, protectiondomain) lt;
460 if (lt.is_enabled()) {
461 ResourceMark rm;
462 // Print out trace information
463 LogStream ls(lt);
464 ls.print_cr("Checking package access");
465 if (class_loader() != NULL) {
466 ls.print("class loader: ");
467 class_loader()->print_value_on(&ls);
468 } else {
469 ls.print_cr("class loader: NULL");
470 }
471 if (protection_domain() != NULL) {
472 ls.print(" protection domain: ");
473 protection_domain()->print_value_on(&ls);
474 } else {
475 ls.print_cr(" protection domain: NULL");
476 }
477 ls.print(" loading: "); klass->print_value_on(&ls);
478 ls.cr();
479 }
480
481 // This handle and the class_loader handle passed in keeps this class from
482 // being unloaded through several GC points.
483 // The class_loader handle passed in is the initiating loader.
484 Handle mirror(THREAD, klass->java_mirror());
485
486 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
487 JavaCalls::call_special(&result,
488 class_loader,
489 system_loader,
490 vmSymbols::checkPackageAccess_name(),
491 vmSymbols::class_protectiondomain_signature(),
492 mirror,
493 protection_domain,
494 THREAD);
495
496 if (HAS_PENDING_EXCEPTION) {
497 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
498 } else {
499 log_debug(protectiondomain)("granted");
500 }
501
502 if (HAS_PENDING_EXCEPTION) return;
503
504 // If no exception has been thrown, we have validated the protection domain
505 // Insert the protection domain of the initiating class into the set.
506 {
507 ClassLoaderData* loader_data = class_loader_data(class_loader);
508 Dictionary* dictionary = loader_data->dictionary();
509
510 Symbol* kn = klass->name();
511 unsigned int d_hash = dictionary->compute_hash(kn);
512
513 MutexLocker mu(SystemDictionary_lock, THREAD);
514 int d_index = dictionary->hash_to_index(d_hash);
515 dictionary->add_protection_domain(d_index, d_hash, klass,
516 protection_domain, THREAD);
517 }
518 }
519
520 // We only get here if this thread finds that another thread
521 // has already claimed the placeholder token for the current operation,
522 // but that other thread either never owned or gave up the
523 // object lock
524 // Waits on SystemDictionary_lock to indicate placeholder table updated
525 // On return, caller must recheck placeholder table state
526 //
527 // We only get here if
528 // 1) custom classLoader, i.e. not bootstrap classloader
529 // 2) custom classLoader has broken the class loader objectLock
530 // so another thread got here in parallel
531 //
532 // lockObject must be held.
533 // Complicated dance due to lock ordering:
534 // Must first release the classloader object lock to
535 // allow initial definer to complete the class definition
536 // and to avoid deadlock
537 // Reclaim classloader lock object with same original recursion count
538 // Must release SystemDictionary_lock after notify, since
539 // class loader lock must be claimed before SystemDictionary_lock
540 // to prevent deadlocks
541 //
542 // The notify allows applications that did an untimed wait() on
543 // the classloader object lock to not hang.
544 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
545 assert_lock_strong(SystemDictionary_lock);
546
547 bool calledholdinglock
548 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
549 assert(calledholdinglock,"must hold lock for notify");
550 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
551 ObjectSynchronizer::notifyall(lockObject, THREAD);
552 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
553 SystemDictionary_lock->wait();
554 SystemDictionary_lock->unlock();
555 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
556 SystemDictionary_lock->lock();
557 }
558
559 // If the class in is in the placeholder table, class loading is in progress
560 // For cases where the application changes threads to load classes, it
561 // is critical to ClassCircularity detection that we try loading
562 // the superclass on the same thread internally, so we do parallel
563 // super class loading here.
564 // This also is critical in cases where the original thread gets stalled
565 // even in non-circularity situations.
566 // Note: must call resolve_super_or_fail even if null super -
567 // to force placeholder entry creation for this class for circularity detection
568 // Caller must check for pending exception
569 // Returns non-null Klass* if other thread has completed load
570 // and we are done,
571 // If return null Klass* and no pending exception, the caller must load the class
572 InstanceKlass* SystemDictionary::handle_parallel_super_load(
573 Symbol* name, Symbol* superclassname, Handle class_loader,
574 Handle protection_domain, Handle lockObject, TRAPS) {
575
576 ClassLoaderData* loader_data = class_loader_data(class_loader);
577 Dictionary* dictionary = loader_data->dictionary();
578 unsigned int d_hash = dictionary->compute_hash(name);
579 unsigned int p_hash = placeholders()->compute_hash(name);
580 int p_index = placeholders()->hash_to_index(p_hash);
581
582 // superk is not used, resolve_super called for circularity check only
583 // This code is reached in two situations. One if this thread
584 // is loading the same class twice (e.g. ClassCircularity, or
585 // java.lang.instrument).
586 // The second is if another thread started the resolve_super first
587 // and has not yet finished.
588 // In both cases the original caller will clean up the placeholder
589 // entry on error.
590 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
591 superclassname,
592 class_loader,
593 protection_domain,
594 true,
595 CHECK_NULL);
596
597 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
598 // Serial class loaders and bootstrap classloader do wait for superclass loads
599 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
600 MutexLocker mu(SystemDictionary_lock, THREAD);
601 // Check if classloading completed while we were loading superclass or waiting
602 return find_class(d_hash, name, dictionary);
603 }
604
605 // must loop to both handle other placeholder updates
606 // and spurious notifications
607 bool super_load_in_progress = true;
608 PlaceholderEntry* placeholder;
609 while (super_load_in_progress) {
610 MutexLocker mu(SystemDictionary_lock, THREAD);
611 // Check if classloading completed while we were loading superclass or waiting
612 InstanceKlass* check = find_class(d_hash, name, dictionary);
613 if (check != NULL) {
614 // Klass is already loaded, so just return it
615 return check;
616 } else {
617 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
618 if (placeholder && placeholder->super_load_in_progress() ){
619 // We only get here if the application has released the
620 // classloader lock when another thread was in the middle of loading a
621 // superclass/superinterface for this class, and now
622 // this thread is also trying to load this class.
623 // To minimize surprises, the first thread that started to
624 // load a class should be the one to complete the loading
625 // with the classfile it initially expected.
626 // This logic has the current thread wait once it has done
627 // all the superclass/superinterface loading it can, until
628 // the original thread completes the class loading or fails
629 // If it completes we will use the resulting InstanceKlass
630 // which we will find below in the systemDictionary.
631 // We also get here for parallel bootstrap classloader
632 if (class_loader.is_null()) {
633 SystemDictionary_lock->wait();
634 } else {
635 double_lock_wait(lockObject, THREAD);
636 }
637 } else {
638 // If not in SD and not in PH, other thread's load must have failed
639 super_load_in_progress = false;
640 }
641 }
642 }
643 return NULL;
644 }
645
646 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
647 assert(event != NULL, "invariant");
648 assert(k != NULL, "invariant");
649 assert(event->should_commit(), "invariant");
650 event->set_loadedClass(k);
651 event->set_definingClassLoader(k->class_loader_data());
652 event->set_initiatingClassLoader(init_cld);
653 event->commit();
654 }
655
656
657 // Be careful when modifying this code: once you have run
658 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
659 // you need to find_and_remove it before returning.
660 // So be careful to not exit with a CHECK_ macro betweeen these calls.
661 //
662 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
663 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
664 Handle class_loader,
665 Handle protection_domain,
666 TRAPS) {
667 assert(name != NULL && !FieldType::is_array(name) &&
668 !FieldType::is_obj(name), "invalid class name");
669
670 EventClassLoad class_load_start_event;
671
672 HandleMark hm(THREAD);
673
674 // Fix for 4474172; see evaluation for more details
675 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
676 ClassLoaderData* loader_data = register_loader(class_loader);
677 Dictionary* dictionary = loader_data->dictionary();
678 unsigned int d_hash = dictionary->compute_hash(name);
679
680 // Do lookup to see if class already exist and the protection domain
681 // has the right access
682 // This call uses find which checks protection domain already matches
683 // All subsequent calls use find_class, and set has_loaded_class so that
684 // before we return a result we call out to java to check for valid protection domain
685 // to allow returning the Klass* and add it to the pd_set if it is valid
686 {
687 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
688 if (probe != NULL) return probe;
689 }
690
691 // Non-bootstrap class loaders will call out to class loader and
692 // define via jvm/jni_DefineClass which will acquire the
693 // class loader object lock to protect against multiple threads
694 // defining the class in parallel by accident.
695 // This lock must be acquired here so the waiter will find
696 // any successful result in the SystemDictionary and not attempt
697 // the define.
698 // ParallelCapable Classloaders and the bootstrap classloader
699 // do not acquire lock here.
700 bool DoObjectLock = true;
701 if (is_parallelCapable(class_loader)) {
702 DoObjectLock = false;
703 }
704
705 unsigned int p_hash = placeholders()->compute_hash(name);
706 int p_index = placeholders()->hash_to_index(p_hash);
707
708 // Class is not in SystemDictionary so we have to do loading.
709 // Make sure we are synchronized on the class loader before we proceed
710 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
711 check_loader_lock_contention(lockObject, THREAD);
712 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
713
714 // Check again (after locking) if class already exist in SystemDictionary
715 bool class_has_been_loaded = false;
716 bool super_load_in_progress = false;
717 bool havesupername = false;
718 InstanceKlass* k = NULL;
719 PlaceholderEntry* placeholder;
720 Symbol* superclassname = NULL;
721
722 assert(THREAD->can_call_java(),
723 "can not load classes with compiler thread: class=%s, classloader=%s",
724 name->as_C_string(),
725 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
726 {
727 MutexLocker mu(SystemDictionary_lock, THREAD);
728 InstanceKlass* check = find_class(d_hash, name, dictionary);
729 if (check != NULL) {
730 // InstanceKlass is already loaded, so just return it
731 class_has_been_loaded = true;
732 k = check;
733 } else {
734 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
735 if (placeholder && placeholder->super_load_in_progress()) {
736 super_load_in_progress = true;
737 if (placeholder->havesupername() == true) {
738 superclassname = placeholder->supername();
739 havesupername = true;
740 }
741 }
742 }
743 }
744
745 // If the class is in the placeholder table, class loading is in progress
746 if (super_load_in_progress && havesupername==true) {
747 k = handle_parallel_super_load(name,
748 superclassname,
749 class_loader,
750 protection_domain,
751 lockObject, THREAD);
752 if (HAS_PENDING_EXCEPTION) {
753 return NULL;
754 }
755 if (k != NULL) {
756 class_has_been_loaded = true;
757 }
758 }
759
760 bool throw_circularity_error = false;
761 if (!class_has_been_loaded) {
762 bool load_instance_added = false;
763
764 // add placeholder entry to record loading instance class
765 // Five cases:
766 // All cases need to prevent modifying bootclasssearchpath
767 // in parallel with a classload of same classname
768 // Redefineclasses uses existence of the placeholder for the duration
769 // of the class load to prevent concurrent redefinition of not completely
770 // defined classes.
771 // case 1. traditional classloaders that rely on the classloader object lock
772 // - no other need for LOAD_INSTANCE
773 // case 2. traditional classloaders that break the classloader object lock
774 // as a deadlock workaround. Detection of this case requires that
775 // this check is done while holding the classloader object lock,
776 // and that lock is still held when calling classloader's loadClass.
777 // For these classloaders, we ensure that the first requestor
778 // completes the load and other requestors wait for completion.
779 // case 3. Bootstrap classloader - don't own objectLocker
780 // This classloader supports parallelism at the classloader level,
781 // but only allows a single load of a class/classloader pair.
782 // No performance benefit and no deadlock issues.
783 // case 4. parallelCapable user level classloaders - without objectLocker
784 // Allow parallel classloading of a class/classloader pair
785
786 {
787 MutexLocker mu(SystemDictionary_lock, THREAD);
788 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
789 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
790 if (oldprobe) {
791 // only need check_seen_thread once, not on each loop
792 // 6341374 java/lang/Instrument with -Xcomp
793 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
794 throw_circularity_error = true;
795 } else {
796 // case 1: traditional: should never see load_in_progress.
797 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
798
799 // case 3: bootstrap classloader: prevent futile classloading,
800 // wait on first requestor
801 if (class_loader.is_null()) {
802 SystemDictionary_lock->wait();
803 } else {
804 // case 2: traditional with broken classloader lock. wait on first
805 // requestor.
806 double_lock_wait(lockObject, THREAD);
807 }
808 // Check if classloading completed while we were waiting
809 InstanceKlass* check = find_class(d_hash, name, dictionary);
810 if (check != NULL) {
811 // Klass is already loaded, so just return it
812 k = check;
813 class_has_been_loaded = true;
814 }
815 // check if other thread failed to load and cleaned up
816 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
817 }
818 }
819 }
820 }
821 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
822 // case 4: parallelCapable: allow competing threads to try
823 // LOAD_INSTANCE in parallel
824
825 if (!throw_circularity_error && !class_has_been_loaded) {
826 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
827 load_instance_added = true;
828 // For class loaders that do not acquire the classloader object lock,
829 // if they did not catch another thread holding LOAD_INSTANCE,
830 // need a check analogous to the acquire ObjectLocker/find_class
831 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
832 // one final check if the load has already completed
833 // class loaders holding the ObjectLock shouldn't find the class here
834 InstanceKlass* check = find_class(d_hash, name, dictionary);
835 if (check != NULL) {
836 // Klass is already loaded, so return it after checking/adding protection domain
837 k = check;
838 class_has_been_loaded = true;
839 }
840 }
841 }
842
843 // must throw error outside of owning lock
844 if (throw_circularity_error) {
845 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
846 ResourceMark rm(THREAD);
847 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
848 }
849
850 if (!class_has_been_loaded) {
851
852 // Do actual loading
853 k = load_instance_class(name, class_loader, THREAD);
854
855 // If everything was OK (no exceptions, no null return value), and
856 // class_loader is NOT the defining loader, do a little more bookkeeping.
857 if (!HAS_PENDING_EXCEPTION && k != NULL &&
858 !oopDesc::equals(k->class_loader(), class_loader())) {
859
860 check_constraints(d_hash, k, class_loader, false, THREAD);
861
862 // Need to check for a PENDING_EXCEPTION again; check_constraints
863 // can throw and doesn't use the CHECK macro.
864 if (!HAS_PENDING_EXCEPTION) {
865 { // Grabbing the Compile_lock prevents systemDictionary updates
866 // during compilations.
867 MutexLocker mu(Compile_lock, THREAD);
868 update_dictionary(d_hash, p_index, p_hash,
869 k, class_loader, THREAD);
870 }
871
872 if (JvmtiExport::should_post_class_load()) {
873 Thread *thread = THREAD;
874 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
875 JvmtiExport::post_class_load((JavaThread *) thread, k);
876 }
877 }
878 }
879 } // load_instance_class
880
881 if (load_instance_added == true) {
882 // clean up placeholder entries for LOAD_INSTANCE success or error
883 // This brackets the SystemDictionary updates for both defining
884 // and initiating loaders
885 MutexLocker mu(SystemDictionary_lock, THREAD);
886 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
887 SystemDictionary_lock->notify_all();
888 }
889 }
890
891 if (HAS_PENDING_EXCEPTION || k == NULL) {
892 return NULL;
893 }
894 if (class_load_start_event.should_commit()) {
895 post_class_load_event(&class_load_start_event, k, loader_data);
896 }
897 #ifdef ASSERT
898 {
899 ClassLoaderData* loader_data = k->class_loader_data();
900 MutexLocker mu(SystemDictionary_lock, THREAD);
901 InstanceKlass* kk = find_class(name, loader_data);
902 assert(kk == k, "should be present in dictionary");
903 }
904 #endif
905
906 // return if the protection domain in NULL
907 if (protection_domain() == NULL) return k;
908
909 // Check the protection domain has the right access
910 if (dictionary->is_valid_protection_domain(d_hash, name,
911 protection_domain)) {
912 return k;
913 }
914
915 // Verify protection domain. If it fails an exception is thrown
916 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
917
918 return k;
919 }
920
921
922 // This routine does not lock the system dictionary.
923 //
924 // Since readers don't hold a lock, we must make sure that system
925 // dictionary entries are only removed at a safepoint (when only one
926 // thread is running), and are added to in a safe way (all links must
927 // be updated in an MT-safe manner).
928 //
929 // Callers should be aware that an entry could be added just after
930 // _dictionary->bucket(index) is read here, so the caller will not see
931 // the new entry.
932
933 Klass* SystemDictionary::find(Symbol* class_name,
934 Handle class_loader,
935 Handle protection_domain,
936 TRAPS) {
937
938 // The result of this call should be consistent with the result
939 // of the call to resolve_instance_class_or_null().
940 // See evaluation 6790209 and 4474172 for more details.
941 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
942 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
943
944 if (loader_data == NULL) {
945 // If the ClassLoaderData has not been setup,
946 // then the class loader has no entries in the dictionary.
947 return NULL;
948 }
949
950 Dictionary* dictionary = loader_data->dictionary();
951 unsigned int d_hash = dictionary->compute_hash(class_name);
952 return dictionary->find(d_hash, class_name,
953 protection_domain);
954 }
955
956
957 // Look for a loaded instance or array klass by name. Do not do any loading.
958 // return NULL in case of error.
959 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
960 Handle class_loader,
961 Handle protection_domain,
962 TRAPS) {
963 Klass* k = NULL;
964 assert(class_name != NULL, "class name must be non NULL");
965
966 if (FieldType::is_array(class_name)) {
967 // The name refers to an array. Parse the name.
968 // dimension and object_key in FieldArrayInfo are assigned as a
969 // side-effect of this call
970 FieldArrayInfo fd;
971 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
972 if (t != T_OBJECT) {
973 k = Universe::typeArrayKlassObj(t);
974 } else {
975 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
976 }
977 if (k != NULL) {
978 k = k->array_klass_or_null(fd.dimension());
979 }
980 } else {
981 k = find(class_name, class_loader, protection_domain, THREAD);
982 }
983 return k;
984 }
985
986 // Note: this method is much like resolve_from_stream, but
987 // does not publish the classes via the SystemDictionary.
988 // Handles unsafe_DefineAnonymousClass and redefineclasses
989 // RedefinedClasses do not add to the class hierarchy
990 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
991 Handle class_loader,
992 Handle protection_domain,
993 ClassFileStream* st,
994 const InstanceKlass* unsafe_anonymous_host,
995 GrowableArray<Handle>* cp_patches,
996 TRAPS) {
997
998 EventClassLoad class_load_start_event;
999
1000 ClassLoaderData* loader_data;
1001 if (unsafe_anonymous_host != NULL) {
1002 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1003 // as the unsafe_anonymous_host
1004 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1005 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1006 } else {
1007 loader_data = ClassLoaderData::class_loader_data(class_loader());
1008 }
1009
1010 assert(st != NULL, "invariant");
1011 assert(st->need_verify(), "invariant");
1012
1013 // Parse stream and create a klass.
1014 // Note that we do this even though this klass might
1015 // already be present in the SystemDictionary, otherwise we would not
1016 // throw potential ClassFormatErrors.
1017
1018 InstanceKlass* k = KlassFactory::create_from_stream(st,
1019 class_name,
1020 loader_data,
1021 protection_domain,
1022 unsafe_anonymous_host,
1023 cp_patches,
1024 CHECK_NULL);
1025
1026 if (unsafe_anonymous_host != NULL && k != NULL) {
1027 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1028 // so that they can be unloaded when the mirror is no longer referenced.
1029 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1030
1031 {
1032 MutexLocker mu_r(Compile_lock, THREAD);
1033
1034 // Add to class hierarchy, initialize vtables, and do possible
1035 // deoptimizations.
1036 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1037
1038 // But, do not add to dictionary.
1039
1040 // compiled code dependencies need to be validated anyway
1041 notice_modification();
1042 }
1043
1044 // Rewrite and patch constant pool here.
1045 k->link_class(CHECK_NULL);
1046 if (cp_patches != NULL) {
1047 k->constants()->patch_resolved_references(cp_patches);
1048 }
1049
1050 // If it's anonymous, initialize it now, since nobody else will.
1051 k->eager_initialize(CHECK_NULL);
1052
1053 // notify jvmti
1054 if (JvmtiExport::should_post_class_load()) {
1055 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1056 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1057 }
1058 if (class_load_start_event.should_commit()) {
1059 post_class_load_event(&class_load_start_event, k, loader_data);
1060 }
1061 }
1062 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1063 "cp_patches only found with unsafe_anonymous_host");
1064
1065 return k;
1066 }
1067
1068 // Add a klass to the system from a stream (called by jni_DefineClass and
1069 // JVM_DefineClass).
1070 // Note: class_name can be NULL. In that case we do not know the name of
1071 // the class until we have parsed the stream.
1072
1073 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1074 Handle class_loader,
1075 Handle protection_domain,
1076 ClassFileStream* st,
1077 TRAPS) {
1078
1079 HandleMark hm(THREAD);
1080
1081 // Classloaders that support parallelism, e.g. bootstrap classloader,
1082 // do not acquire lock here
1083 bool DoObjectLock = true;
1084 if (is_parallelCapable(class_loader)) {
1085 DoObjectLock = false;
1086 }
1087
1088 ClassLoaderData* loader_data = register_loader(class_loader);
1089
1090 // Make sure we are synchronized on the class loader before we proceed
1091 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1092 check_loader_lock_contention(lockObject, THREAD);
1093 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1094
1095 assert(st != NULL, "invariant");
1096
1097 // Parse the stream and create a klass.
1098 // Note that we do this even though this klass might
1099 // already be present in the SystemDictionary, otherwise we would not
1100 // throw potential ClassFormatErrors.
1101 InstanceKlass* k = NULL;
1102
1103 #if INCLUDE_CDS
1104 if (!DumpSharedSpaces) {
1105 k = SystemDictionaryShared::lookup_from_stream(class_name,
1106 class_loader,
1107 protection_domain,
1108 st,
1109 CHECK_NULL);
1110 }
1111 #endif
1112
1113 if (k == NULL) {
1114 if (st->buffer() == NULL) {
1115 return NULL;
1116 }
1117 k = KlassFactory::create_from_stream(st,
1118 class_name,
1119 loader_data,
1120 protection_domain,
1121 NULL, // unsafe_anonymous_host
1122 NULL, // cp_patches
1123 CHECK_NULL);
1124 }
1125
1126 assert(k != NULL, "no klass created");
1127 Symbol* h_name = k->name();
1128 assert(class_name == NULL || class_name == h_name, "name mismatch");
1129
1130 // Add class just loaded
1131 // If a class loader supports parallel classloading handle parallel define requests
1132 // find_or_define_instance_class may return a different InstanceKlass
1133 if (is_parallelCapable(class_loader)) {
1134 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1135 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1136 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1137 assert(defined_k != NULL, "Should have a klass if there's no exception");
1138 loader_data->add_to_deallocate_list(k);
1139 k = defined_k;
1140 }
1141 } else {
1142 define_instance_class(k, THREAD);
1143 }
1144
1145 // If defining the class throws an exception register 'k' for cleanup.
1146 if (HAS_PENDING_EXCEPTION) {
1147 assert(k != NULL, "Must have an instance klass here!");
1148 loader_data->add_to_deallocate_list(k);
1149 return NULL;
1150 }
1151
1152 // Make sure we have an entry in the SystemDictionary on success
1153 debug_only( {
1154 MutexLocker mu(SystemDictionary_lock, THREAD);
1155
1156 Klass* check = find_class(h_name, k->class_loader_data());
1157 assert(check == k, "should be present in the dictionary");
1158 } );
1159
1160 return k;
1161 }
1162
1163 #if INCLUDE_CDS
1164 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1165 int number_of_entries) {
1166 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
1167 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1168 "bad shared dictionary size.");
1169 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1170 _shared_dictionary_size, t, number_of_entries,
1171 false /* explicitly set _resizable to false */);
1172 }
1173
1174
1175 // If there is a shared dictionary, then find the entry for the
1176 // given shared system class, if any.
1177
1178 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1179 if (shared_dictionary() != NULL) {
1180 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1181 int d_index = shared_dictionary()->hash_to_index(d_hash);
1182
1183 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1184 } else {
1185 return NULL;
1186 }
1187 }
1188
1189
1190 // Load a class from the shared spaces (found through the shared system
1191 // dictionary). Force the superclass and all interfaces to be loaded.
1192 // Update the class definition to include sibling classes and no
1193 // subclasses (yet). [Classes in the shared space are not part of the
1194 // object hierarchy until loaded.]
1195
1196 InstanceKlass* SystemDictionary::load_shared_class(
1197 Symbol* class_name, Handle class_loader, TRAPS) {
1198 InstanceKlass* ik = find_shared_class(class_name);
1199 // Make sure we only return the boot class for the NULL classloader.
1200 if (ik != NULL &&
1201 ik->is_shared_boot_class() && class_loader.is_null()) {
1202 Handle protection_domain;
1203 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1204 }
1205 return NULL;
1206 }
1207
1208 // Check if a shared class can be loaded by the specific classloader:
1209 //
1210 // NULL classloader:
1211 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1212 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1213 // be defined in an unnamed module.
1214 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1215 InstanceKlass* ik,
1216 Handle class_loader, TRAPS) {
1217 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1218 "Cannot use sharing if java.base is patched");
1219 ResourceMark rm;
1220 int path_index = ik->shared_classpath_index();
1221 ClassLoaderData* loader_data = class_loader_data(class_loader);
1222 if (path_index < 0) {
1223 // path_index < 0 indicates that the class is intended for a custom loader
1224 // and should not be loaded by boot/platform/app loaders
1225 if (loader_data->is_builtin_class_loader_data()) {
1226 return false;
1227 } else {
1228 return true;
1229 }
1230 }
1231 SharedClassPathEntry* ent =
1232 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1233 if (!Universe::is_module_initialized()) {
1234 assert(ent != NULL && ent->is_modules_image(),
1235 "Loading non-bootstrap classes before the module system is initialized");
1236 assert(class_loader.is_null(), "sanity");
1237 return true;
1238 }
1239 // Get the pkg_entry from the classloader
1240 TempNewSymbol pkg_name = NULL;
1241 PackageEntry* pkg_entry = NULL;
1242 ModuleEntry* mod_entry = NULL;
1243 const char* pkg_string = NULL;
1244 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1245 if (pkg_name != NULL) {
1246 pkg_string = pkg_name->as_C_string();
1247 if (loader_data != NULL) {
1248 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1249 }
1250 if (pkg_entry != NULL) {
1251 mod_entry = pkg_entry->module();
1252 }
1253 }
1254
1255 // If the archived class is from a module that has been patched at runtime,
1256 // the class cannot be loaded from the archive.
1257 if (mod_entry != NULL && mod_entry->is_patched()) {
1258 return false;
1259 }
1260
1261 if (class_loader.is_null()) {
1262 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1263 // The NULL classloader can load archived class originated from the
1264 // "modules" jimage and the -Xbootclasspath/a. For class from the
1265 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1266 // by the NULL classloader.
1267 if (mod_entry != NULL) {
1268 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1269 // ModuleEntry's location agrees with the archived class' origination.
1270 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1271 return true; // Module class from the "module" jimage
1272 }
1273 }
1274
1275 // If the archived class is not from the "module" jimage, the class can be
1276 // loaded by the NULL classloader if
1277 //
1278 // 1. the class is from the unamed package
1279 // 2. or, the class is not from a module defined in the NULL classloader
1280 // 3. or, the class is from an unamed module
1281 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1282 // the class is from the -Xbootclasspath/a
1283 if (pkg_string == NULL ||
1284 pkg_entry == NULL ||
1285 pkg_entry->in_unnamed_module()) {
1286 assert(mod_entry == NULL ||
1287 mod_entry == loader_data->unnamed_module(),
1288 "the unnamed module is not defined in the classloader");
1289 return true;
1290 }
1291 }
1292 return false;
1293 } else {
1294 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1295 ik, class_loader, pkg_string, pkg_name,
1296 pkg_entry, mod_entry, CHECK_(false));
1297 return res;
1298 }
1299 }
1300
1301 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1302 Handle class_loader,
1303 Handle protection_domain, TRAPS) {
1304
1305 if (ik != NULL) {
1306 Symbol* class_name = ik->name();
1307
1308 bool visible = is_shared_class_visible(
1309 class_name, ik, class_loader, CHECK_NULL);
1310 if (!visible) {
1311 return NULL;
1312 }
1313
1314 // Resolve the superclass and interfaces. They must be the same
1315 // as in dump time, because the layout of <ik> depends on
1316 // the specific layout of ik->super() and ik->local_interfaces().
1317 //
1318 // If unexpected superclass or interfaces are found, we cannot
1319 // load <ik> from the shared archive.
1320
1321 if (ik->super() != NULL) {
1322 Symbol* cn = ik->super()->name();
1323 Klass *s = resolve_super_or_fail(class_name, cn,
1324 class_loader, protection_domain, true, CHECK_NULL);
1325 if (s != ik->super()) {
1326 // The dynamically resolved super class is not the same as the one we used during dump time,
1327 // so we cannot use ik.
1328 return NULL;
1329 } else {
1330 assert(s->is_shared(), "must be");
1331 }
1332 }
1333
1334 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1335 int num_interfaces = interfaces->length();
1336 for (int index = 0; index < num_interfaces; index++) {
1337 InstanceKlass* k = interfaces->at(index);
1338 Symbol* name = k->name();
1339 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1340 if (k != i) {
1341 // The dynamically resolved interface class is not the same as the one we used during dump time,
1342 // so we cannot use ik.
1343 return NULL;
1344 } else {
1345 assert(i->is_shared(), "must be");
1346 }
1347 }
1348
1349 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1350 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1351 if (new_ik != NULL) {
1352 // The class is changed by CFLH. Return the new class. The shared class is
1353 // not used.
1354 return new_ik;
1355 }
1356
1357 // Adjust methods to recover missing data. They need addresses for
1358 // interpreter entry points and their default native method address
1359 // must be reset.
1360
1361 // Updating methods must be done under a lock so multiple
1362 // threads don't update these in parallel
1363 //
1364 // Shared classes are all currently loaded by either the bootstrap or
1365 // internal parallel class loaders, so this will never cause a deadlock
1366 // on a custom class loader lock.
1367
1368 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1369 {
1370 HandleMark hm(THREAD);
1371 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1372 check_loader_lock_contention(lockObject, THREAD);
1373 ObjectLocker ol(lockObject, THREAD, true);
1374 // prohibited package check assumes all classes loaded from archive call
1375 // restore_unshareable_info which calls ik->set_package()
1376 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1377 }
1378
1379 ik->print_class_load_logging(loader_data, NULL, NULL);
1380
1381 // For boot loader, ensure that GetSystemPackage knows that a class in this
1382 // package was loaded.
1383 if (class_loader.is_null()) {
1384 int path_index = ik->shared_classpath_index();
1385 ResourceMark rm;
1386 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1387 }
1388
1389 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1390 // Only dump the classes that can be stored into CDS archive
1391 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1392 ResourceMark rm(THREAD);
1393 classlist_file->print_cr("%s", ik->name()->as_C_string());
1394 classlist_file->flush();
1395 }
1396 }
1397
1398 // notify a class loaded from shared object
1399 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1400
1401 ik->set_has_passed_fingerprint_check(false);
1402 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1403 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1404 uint64_t cds_fp = ik->get_stored_fingerprint();
1405 if (aot_fp != 0 && aot_fp == cds_fp) {
1406 // This class matches with a class saved in an AOT library
1407 ik->set_has_passed_fingerprint_check(true);
1408 } else {
1409 ResourceMark rm;
1410 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1411 }
1412 }
1413 }
1414 return ik;
1415 }
1416
1417 void SystemDictionary::clear_invoke_method_table() {
1418 SymbolPropertyEntry* spe = NULL;
1419 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1420 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1421 while (p != NULL) {
1422 spe = p;
1423 p = p->next();
1424 _invoke_method_table->free_entry(spe);
1425 }
1426 }
1427 }
1428 #endif // INCLUDE_CDS
1429
1430 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1431
1432 if (class_loader.is_null()) {
1433 ResourceMark rm;
1434 PackageEntry* pkg_entry = NULL;
1435 bool search_only_bootloader_append = false;
1436 ClassLoaderData *loader_data = class_loader_data(class_loader);
1437
1438 // Find the package in the boot loader's package entry table.
1439 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1440 if (pkg_name != NULL) {
1441 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1442 }
1443
1444 // Prior to attempting to load the class, enforce the boot loader's
1445 // visibility boundaries.
1446 if (!Universe::is_module_initialized()) {
1447 // During bootstrapping, prior to module initialization, any
1448 // class attempting to be loaded must be checked against the
1449 // java.base packages in the boot loader's PackageEntryTable.
1450 // No class outside of java.base is allowed to be loaded during
1451 // this bootstrapping window.
1452 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1453 // Class is either in the unnamed package or in
1454 // a named package within the unnamed module. Either
1455 // case is outside of java.base, do not attempt to
1456 // load the class post java.base definition. If
1457 // java.base has not been defined, let the class load
1458 // and its package will be checked later by
1459 // ModuleEntryTable::verify_javabase_packages.
1460 if (ModuleEntryTable::javabase_defined()) {
1461 return NULL;
1462 }
1463 } else {
1464 // Check that the class' package is defined within java.base.
1465 ModuleEntry* mod_entry = pkg_entry->module();
1466 Symbol* mod_entry_name = mod_entry->name();
1467 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1468 return NULL;
1469 }
1470 }
1471 } else {
1472 // After the module system has been initialized, check if the class'
1473 // package is in a module defined to the boot loader.
1474 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1475 // Class is either in the unnamed package, in a named package
1476 // within a module not defined to the boot loader or in a
1477 // a named package within the unnamed module. In all cases,
1478 // limit visibility to search for the class only in the boot
1479 // loader's append path.
1480 search_only_bootloader_append = true;
1481 }
1482 }
1483
1484 // Prior to bootstrapping's module initialization, never load a class outside
1485 // of the boot loader's module path
1486 assert(Universe::is_module_initialized() ||
1487 !search_only_bootloader_append,
1488 "Attempt to load a class outside of boot loader's module path");
1489
1490 // Search the shared system dictionary for classes preloaded into the
1491 // shared spaces.
1492 InstanceKlass* k = NULL;
1493 {
1494 #if INCLUDE_CDS
1495 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1496 k = load_shared_class(class_name, class_loader, THREAD);
1497 #endif
1498 }
1499
1500 if (k == NULL) {
1501 // Use VM class loader
1502 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1503 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1504 }
1505
1506 // find_or_define_instance_class may return a different InstanceKlass
1507 if (k != NULL) {
1508 InstanceKlass* defined_k =
1509 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1510 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1511 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1512 assert(defined_k != NULL, "Should have a klass if there's no exception");
1513 loader_data->add_to_deallocate_list(k);
1514 k = defined_k;
1515 } else if (HAS_PENDING_EXCEPTION) {
1516 loader_data->add_to_deallocate_list(k);
1517 return NULL;
1518 }
1519 }
1520 return k;
1521 } else {
1522 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1523 ResourceMark rm(THREAD);
1524
1525 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1526 JavaThread* jt = (JavaThread*) THREAD;
1527
1528 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1529 ClassLoader::perf_app_classload_selftime(),
1530 ClassLoader::perf_app_classload_count(),
1531 jt->get_thread_stat()->perf_recursion_counts_addr(),
1532 jt->get_thread_stat()->perf_timers_addr(),
1533 PerfClassTraceTime::CLASS_LOAD);
1534
1535 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1536 // Translate to external class name format, i.e., convert '/' chars to '.'
1537 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1538
1539 JavaValue result(T_OBJECT);
1540
1541 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1542
1543 // Call public unsynchronized loadClass(String) directly for all class loaders.
1544 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1545 // acquire a class-name based lock rather than the class loader object lock.
1546 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1547 JavaCalls::call_virtual(&result,
1548 class_loader,
1549 spec_klass,
1550 vmSymbols::loadClass_name(),
1551 vmSymbols::string_class_signature(),
1552 string,
1553 CHECK_NULL);
1554
1555 assert(result.get_type() == T_OBJECT, "just checking");
1556 oop obj = (oop) result.get_jobject();
1557
1558 // Primitive classes return null since forName() can not be
1559 // used to obtain any of the Class objects representing primitives or void
1560 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1561 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1562 // For user defined Java class loaders, check that the name returned is
1563 // the same as that requested. This check is done for the bootstrap
1564 // loader when parsing the class file.
1565 if (class_name == k->name()) {
1566 return k;
1567 }
1568 }
1569 // Class is not found or has the wrong name, return NULL
1570 return NULL;
1571 }
1572 }
1573
1574 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1575 EventClassDefine event;
1576 if (event.should_commit()) {
1577 event.set_definedClass(k);
1578 event.set_definingClassLoader(def_cld);
1579 event.commit();
1580 }
1581 }
1582
1583 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1584
1585 HandleMark hm(THREAD);
1586 ClassLoaderData* loader_data = k->class_loader_data();
1587 Handle class_loader_h(THREAD, loader_data->class_loader());
1588
1589 // for bootstrap and other parallel classloaders don't acquire lock,
1590 // use placeholder token
1591 // If a parallelCapable class loader calls define_instance_class instead of
1592 // find_or_define_instance_class to get here, we have a timing
1593 // hole with systemDictionary updates and check_constraints
1594 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1595 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1596 compute_loader_lock_object(class_loader_h, THREAD)),
1597 "define called without lock");
1598 }
1599
1600 // Check class-loading constraints. Throw exception if violation is detected.
1601 // Grabs and releases SystemDictionary_lock
1602 // The check_constraints/find_class call and update_dictionary sequence
1603 // must be "atomic" for a specific class/classloader pair so we never
1604 // define two different instanceKlasses for that class/classloader pair.
1605 // Existing classloaders will call define_instance_class with the
1606 // classloader lock held
1607 // Parallel classloaders will call find_or_define_instance_class
1608 // which will require a token to perform the define class
1609 Symbol* name_h = k->name();
1610 Dictionary* dictionary = loader_data->dictionary();
1611 unsigned int d_hash = dictionary->compute_hash(name_h);
1612 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1613
1614 // Register class just loaded with class loader (placed in Vector)
1615 // Note we do this before updating the dictionary, as this can
1616 // fail with an OutOfMemoryError (if it does, we will *not* put this
1617 // class in the dictionary and will not update the class hierarchy).
1618 // JVMTI FollowReferences needs to find the classes this way.
1619 if (k->class_loader() != NULL) {
1620 methodHandle m(THREAD, Universe::loader_addClass_method());
1621 JavaValue result(T_VOID);
1622 JavaCallArguments args(class_loader_h);
1623 args.push_oop(Handle(THREAD, k->java_mirror()));
1624 JavaCalls::call(&result, m, &args, CHECK);
1625 }
1626
1627 // Add the new class. We need recompile lock during update of CHA.
1628 {
1629 unsigned int p_hash = placeholders()->compute_hash(name_h);
1630 int p_index = placeholders()->hash_to_index(p_hash);
1631
1632 MutexLocker mu_r(Compile_lock, THREAD);
1633
1634 // Add to class hierarchy, initialize vtables, and do possible
1635 // deoptimizations.
1636 add_to_hierarchy(k, CHECK); // No exception, but can block
1637
1638 // Add to systemDictionary - so other classes can see it.
1639 // Grabs and releases SystemDictionary_lock
1640 update_dictionary(d_hash, p_index, p_hash,
1641 k, class_loader_h, THREAD);
1642 }
1643 k->eager_initialize(THREAD);
1644
1645 // notify jvmti
1646 if (JvmtiExport::should_post_class_load()) {
1647 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1648 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1649
1650 }
1651 post_class_define_event(k, loader_data);
1652 }
1653
1654 // Support parallel classloading
1655 // All parallel class loaders, including bootstrap classloader
1656 // lock a placeholder entry for this class/class_loader pair
1657 // to allow parallel defines of different classes for this class loader
1658 // With AllowParallelDefine flag==true, in case they do not synchronize around
1659 // FindLoadedClass/DefineClass, calls, we check for parallel
1660 // loading for them, wait if a defineClass is in progress
1661 // and return the initial requestor's results
1662 // This flag does not apply to the bootstrap classloader.
1663 // With AllowParallelDefine flag==false, call through to define_instance_class
1664 // which will throw LinkageError: duplicate class definition.
1665 // False is the requested default.
1666 // For better performance, the class loaders should synchronize
1667 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1668 // potentially waste time reading and parsing the bytestream.
1669 // Note: VM callers should ensure consistency of k/class_name,class_loader
1670 // Be careful when modifying this code: once you have run
1671 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1672 // you need to find_and_remove it before returning.
1673 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1674 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1675 InstanceKlass* k, TRAPS) {
1676
1677 Symbol* name_h = k->name(); // passed in class_name may be null
1678 ClassLoaderData* loader_data = class_loader_data(class_loader);
1679 Dictionary* dictionary = loader_data->dictionary();
1680
1681 unsigned int d_hash = dictionary->compute_hash(name_h);
1682
1683 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1684 unsigned int p_hash = placeholders()->compute_hash(name_h);
1685 int p_index = placeholders()->hash_to_index(p_hash);
1686 PlaceholderEntry* probe;
1687
1688 {
1689 MutexLocker mu(SystemDictionary_lock, THREAD);
1690 // First check if class already defined
1691 if (is_parallelDefine(class_loader)) {
1692 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1693 if (check != NULL) {
1694 return check;
1695 }
1696 }
1697
1698 // Acquire define token for this class/classloader
1699 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1700 // Wait if another thread defining in parallel
1701 // All threads wait - even those that will throw duplicate class: otherwise
1702 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1703 // if other thread has not finished updating dictionary
1704 while (probe->definer() != NULL) {
1705 SystemDictionary_lock->wait();
1706 }
1707 // Only special cases allow parallel defines and can use other thread's results
1708 // Other cases fall through, and may run into duplicate defines
1709 // caught by finding an entry in the SystemDictionary
1710 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1711 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1712 SystemDictionary_lock->notify_all();
1713 #ifdef ASSERT
1714 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1715 assert(check != NULL, "definer missed recording success");
1716 #endif
1717 return probe->instance_klass();
1718 } else {
1719 // This thread will define the class (even if earlier thread tried and had an error)
1720 probe->set_definer(THREAD);
1721 }
1722 }
1723
1724 define_instance_class(k, THREAD);
1725
1726 Handle linkage_exception = Handle(); // null handle
1727
1728 // definer must notify any waiting threads
1729 {
1730 MutexLocker mu(SystemDictionary_lock, THREAD);
1731 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1732 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1733 if (probe != NULL) {
1734 if (HAS_PENDING_EXCEPTION) {
1735 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1736 CLEAR_PENDING_EXCEPTION;
1737 } else {
1738 probe->set_instance_klass(k);
1739 }
1740 probe->set_definer(NULL);
1741 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1742 SystemDictionary_lock->notify_all();
1743 }
1744 }
1745
1746 // Can't throw exception while holding lock due to rank ordering
1747 if (linkage_exception() != NULL) {
1748 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1749 }
1750
1751 return k;
1752 }
1753
1754 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1755 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1756 if (class_loader.is_null()) {
1757 return Handle(THREAD, _system_loader_lock_obj);
1758 } else {
1759 return class_loader;
1760 }
1761 }
1762
1763 // This method is added to check how often we have to wait to grab loader
1764 // lock. The results are being recorded in the performance counters defined in
1765 // ClassLoader::_sync_systemLoaderLockContentionRate and
1766 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1767 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1768 if (!UsePerfData) {
1769 return;
1770 }
1771
1772 assert(!loader_lock.is_null(), "NULL lock object");
1773
1774 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1775 == ObjectSynchronizer::owner_other) {
1776 // contention will likely happen, so increment the corresponding
1777 // contention counter.
1778 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1779 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1780 } else {
1781 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1782 }
1783 }
1784 }
1785
1786 // ----------------------------------------------------------------------------
1787 // Lookup
1788
1789 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1790 Symbol* class_name,
1791 Dictionary* dictionary) {
1792 assert_locked_or_safepoint(SystemDictionary_lock);
1793 int index = dictionary->hash_to_index(hash);
1794 return dictionary->find_class(index, hash, class_name);
1795 }
1796
1797
1798 // Basic find on classes in the midst of being loaded
1799 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1800 ClassLoaderData* loader_data) {
1801 assert_locked_or_safepoint(SystemDictionary_lock);
1802 unsigned int p_hash = placeholders()->compute_hash(class_name);
1803 int p_index = placeholders()->hash_to_index(p_hash);
1804 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1805 }
1806
1807
1808 // Used for assertions and verification only
1809 // Precalculating the hash and index is an optimization because there are many lookups
1810 // before adding the class.
1811 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1812 assert_locked_or_safepoint(SystemDictionary_lock);
1813 #ifndef ASSERT
1814 guarantee(VerifyBeforeGC ||
1815 VerifyDuringGC ||
1816 VerifyBeforeExit ||
1817 VerifyDuringStartup ||
1818 VerifyAfterGC, "too expensive");
1819 #endif
1820
1821 Dictionary* dictionary = loader_data->dictionary();
1822 unsigned int d_hash = dictionary->compute_hash(class_name);
1823 return find_class(d_hash, class_name, dictionary);
1824 }
1825
1826
1827 // ----------------------------------------------------------------------------
1828 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1829 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1830 // before a new class is used.
1831
1832 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1833 assert(k != NULL, "just checking");
1834 assert_locked_or_safepoint(Compile_lock);
1835
1836 // Link into hierachy. Make sure the vtables are initialized before linking into
1837 k->append_to_sibling_list(); // add to superklass/sibling list
1838 k->process_interfaces(THREAD); // handle all "implements" declarations
1839 k->set_init_state(InstanceKlass::loaded);
1840 // Now flush all code that depended on old class hierarchy.
1841 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1842 // Also, first reinitialize vtable because it may have gotten out of synch
1843 // while the new class wasn't connected to the class hierarchy.
1844 CodeCache::flush_dependents_on(k);
1845 }
1846
1847 // ----------------------------------------------------------------------------
1848 // GC support
1849
1850 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1851 // Note: anonymous classes are not in the SD.
1852 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1853 bool do_cleaning) {
1854
1855 bool unloading_occurred;
1856 {
1857 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1858
1859 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1860 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1861 if (unloading_occurred) {
1862 JFR_ONLY(Jfr::on_unloading_classes();)
1863 ClassLoaderDataGraph::clean_module_and_package_info();
1864 }
1865 }
1866
1867 // TODO: just return if !unloading_occurred.
1868 if (unloading_occurred) {
1869 {
1870 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
1871 // Check if there's work to do in the SymbolTable
1872 SymbolTable::do_check_concurrent_work();
1873 }
1874
1875 {
1876 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1877 constraints()->purge_loader_constraints();
1878 resolution_errors()->purge_resolution_errors();
1879 }
1880 }
1881
1882 {
1883 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1884 // Oops referenced by the protection domain cache table may get unreachable independently
1885 // of the class loader (eg. cached protection domain oops). So we need to
1886 // explicitly unlink them here.
1887 _pd_cache_table->trigger_cleanup();
1888 }
1889
1890 if (do_cleaning) {
1891 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1892 ResolvedMethodTable::trigger_cleanup();
1893 }
1894
1895 return unloading_occurred;
1896 }
1897
1898 void SystemDictionary::oops_do(OopClosure* f) {
1899 f->do_oop(&_java_system_loader);
1900 f->do_oop(&_java_platform_loader);
1901 f->do_oop(&_system_loader_lock_obj);
1902 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1903
1904 // Visit extra methods
1905 invoke_method_table()->oops_do(f);
1906 }
1907
1908 // CDS: scan and relocate all classes in the system dictionary.
1909 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1910 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1911 }
1912
1913 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1914 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1915 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1916 it->push(well_known_klass_addr((WKID)id));
1917 }
1918 }
1919
1920 void SystemDictionary::methods_do(void f(Method*)) {
1921 // Walk methods in loaded classes
1922 MutexLocker ml(ClassLoaderDataGraph_lock);
1923 ClassLoaderDataGraph::methods_do(f);
1924 // Walk method handle intrinsics
1925 invoke_method_table()->methods_do(f);
1926 }
1927
1928 class RemoveClassesClosure : public CLDClosure {
1929 public:
1930 void do_cld(ClassLoaderData* cld) {
1931 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1932 cld->dictionary()->remove_classes_in_error_state();
1933 }
1934 }
1935 };
1936
1937 void SystemDictionary::remove_classes_in_error_state() {
1938 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1939 RemoveClassesClosure rcc;
1940 MutexLocker ml(ClassLoaderDataGraph_lock);
1941 ClassLoaderDataGraph::cld_do(&rcc);
1942 }
1943
1944 // ----------------------------------------------------------------------------
1945 // Initialization
1946
1947 void SystemDictionary::initialize(TRAPS) {
1948 // Allocate arrays
1949 _placeholders = new PlaceholderTable(_placeholder_table_size);
1950 _number_of_modifications = 0;
1951 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1952 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1953 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1954 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1955
1956 // Allocate private object used as system class loader lock
1957 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1958 // Initialize basic classes
1959 resolve_preloaded_classes(CHECK);
1960 }
1961
1962 // Compact table of directions on the initialization of klasses:
1963 static const short wk_init_info[] = {
1964 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1965 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1966 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1967 | (int)SystemDictionary::option ),
1968 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1969 #undef WK_KLASS_INIT_INFO
1970 0
1971 };
1972
1973 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) {
1974 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1975 int info = wk_init_info[id - FIRST_WKID];
1976 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1977 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1978 InstanceKlass** klassp = &_well_known_klasses[id];
1979
1980 bool must_load;
1981 #if INCLUDE_JVMCI
1982 if (EnableJVMCI) {
1983 // If JVMCI is enabled we require its classes to be found.
1984 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1985 } else
1986 #endif
1987 {
1988 must_load = (init_opt < SystemDictionary::Opt);
1989 }
1990
1991 if ((*klassp) == NULL) {
1992 Klass* k;
1993 if (must_load) {
1994 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
1995 } else {
1996 k = resolve_or_null(symbol, CHECK_0); // load optional klass
1997 }
1998 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
1999 }
2000 return ((*klassp) != NULL);
2001 }
2002
2003 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2004 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2005 for (int id = (int)start_id; id < (int)limit_id; id++) {
2006 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2007 int info = wk_init_info[id - FIRST_WKID];
2008 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2009 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2010
2011 resolve_wk_klass((WKID)id, opt, CHECK);
2012 }
2013
2014 // move the starting value forward to the limit:
2015 start_id = limit_id;
2016 }
2017
2018 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
2019 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2020
2021 // Create the ModuleEntry for java.base. This call needs to be done here,
2022 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2023 ClassLoader::classLoader_init2(CHECK);
2024
2025 // Preload commonly used klasses
2026 WKID scan = FIRST_WKID;
2027 // first do Object, then String, Class
2028 #if INCLUDE_CDS
2029 if (UseSharedSpaces) {
2030 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2031
2032 // It's unsafe to access the archived heap regions before they
2033 // are fixed up, so we must do the fixup as early as possible
2034 // before the archived java objects are accessed by functions
2035 // such as java_lang_Class::restore_archived_mirror and
2036 // ConstantPool::restore_unshareable_info (restores the archived
2037 // resolved_references array object).
2038 //
2039 // MetaspaceShared::fixup_mapped_heap_regions() fills the empty
2040 // spaces in the archived heap regions and may use
2041 // SystemDictionary::Object_klass(), so we can do this only after
2042 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2043 // call. No mirror objects are accessed/restored in the above call.
2044 // Mirrors are restored after java.lang.Class is loaded.
2045 MetaspaceShared::fixup_mapped_heap_regions();
2046
2047 // Initialize the constant pool for the Object_class
2048 Object_klass()->constants()->restore_unshareable_info(CHECK);
2049 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2050 } else
2051 #endif
2052 {
2053 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2054 }
2055
2056 // Calculate offsets for String and Class classes since they are loaded and
2057 // can be used after this point.
2058 java_lang_String::compute_offsets();
2059 java_lang_Class::compute_offsets();
2060
2061 // Fixup mirrors for classes loaded before java.lang.Class.
2062 // These calls iterate over the objects currently in the perm gen
2063 // so calling them at this point is matters (not before when there
2064 // are fewer objects and not later after there are more objects
2065 // in the perm gen.
2066 Universe::initialize_basic_type_mirrors(CHECK);
2067 Universe::fixup_mirrors(CHECK);
2068
2069 // do a bunch more:
2070 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2071
2072 // Preload ref klasses and set reference types
2073 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2074 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2075
2076 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2077 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2078 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2079 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2080 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2081
2082 // JSR 292 classes
2083 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2084 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2085 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2086 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2087 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2088
2089 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2090 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2091 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2092 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2093 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2094 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2095 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2096 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2097 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2098 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2099
2100 { // Compute whether we should use checkPackageAccess or NOT
2101 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2102 _has_checkPackageAccess = (method != NULL);
2103 }
2104 }
2105
2106 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2107 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2108 BasicType SystemDictionary::box_klass_type(Klass* k) {
2109 assert(k != NULL, "");
2110 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2111 if (_box_klasses[i] == k)
2112 return (BasicType)i;
2113 }
2114 return T_OBJECT;
2115 }
2116
2117 // Constraints on class loaders. The details of the algorithm can be
2118 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2119 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2120 // that the dictionary needs to maintain a set of contraints that
2121 // must be satisfied by all classes in the dictionary.
2122 // if defining is true, then LinkageError if already in dictionary
2123 // if initiating loader, then ok if InstanceKlass matches existing entry
2124
2125 void SystemDictionary::check_constraints(unsigned int d_hash,
2126 InstanceKlass* k,
2127 Handle class_loader,
2128 bool defining,
2129 TRAPS) {
2130 ResourceMark rm(THREAD);
2131 stringStream ss;
2132 bool throwException = false;
2133
2134 {
2135 Symbol *name = k->name();
2136 ClassLoaderData *loader_data = class_loader_data(class_loader);
2137
2138 MutexLocker mu(SystemDictionary_lock, THREAD);
2139
2140 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2141 if (check != NULL) {
2142 // If different InstanceKlass - duplicate class definition,
2143 // else - ok, class loaded by a different thread in parallel.
2144 // We should only have found it if it was done loading and ok to use.
2145 // The dictionary only holds instance classes, placeholders
2146 // also hold array classes.
2147
2148 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2149 if ((defining == true) || (k != check)) {
2150 throwException = true;
2151 ss.print("loader %s", loader_data->loader_name_and_id());
2152 ss.print(" attempted duplicate %s definition for %s. (%s)",
2153 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2154 } else {
2155 return;
2156 }
2157 }
2158
2159 #ifdef ASSERT
2160 Symbol* ph_check = find_placeholder(name, loader_data);
2161 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2162 #endif
2163
2164 if (throwException == false) {
2165 if (constraints()->check_or_update(k, class_loader, name) == false) {
2166 throwException = true;
2167 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2168 ss.print(" wants to load %s %s.",
2169 k->external_kind(), k->external_name());
2170 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2171 if (existing_klass->class_loader() != class_loader()) {
2172 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2173 existing_klass->external_kind(),
2174 existing_klass->class_loader_data()->loader_name_and_id(),
2175 existing_klass->class_in_module_of_loader(false, true));
2176 } else {
2177 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2178 }
2179 }
2180 }
2181 }
2182
2183 // Throw error now if needed (cannot throw while holding
2184 // SystemDictionary_lock because of rank ordering)
2185 if (throwException == true) {
2186 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2187 }
2188 }
2189
2190 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2191 // have been called.
2192 void SystemDictionary::update_dictionary(unsigned int d_hash,
2193 int p_index, unsigned int p_hash,
2194 InstanceKlass* k,
2195 Handle class_loader,
2196 TRAPS) {
2197 // Compile_lock prevents systemDictionary updates during compilations
2198 assert_locked_or_safepoint(Compile_lock);
2199 Symbol* name = k->name();
2200 ClassLoaderData *loader_data = class_loader_data(class_loader);
2201
2202 {
2203 MutexLocker mu1(SystemDictionary_lock, THREAD);
2204
2205 // See whether biased locking is enabled and if so set it for this
2206 // klass.
2207 // Note that this must be done past the last potential blocking
2208 // point / safepoint. We enable biased locking lazily using a
2209 // VM_Operation to iterate the SystemDictionary and installing the
2210 // biasable mark word into each InstanceKlass's prototype header.
2211 // To avoid race conditions where we accidentally miss enabling the
2212 // optimization for one class in the process of being added to the
2213 // dictionary, we must not safepoint after the test of
2214 // BiasedLocking::enabled().
2215 if (UseBiasedLocking && BiasedLocking::enabled()) {
2216 // Set biased locking bit for all loaded classes; it will be
2217 // cleared if revocation occurs too often for this type
2218 // NOTE that we must only do this when the class is initally
2219 // defined, not each time it is referenced from a new class loader
2220 if (oopDesc::equals(k->class_loader(), class_loader())) {
2221 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2222 }
2223 }
2224
2225 // Make a new dictionary entry.
2226 Dictionary* dictionary = loader_data->dictionary();
2227 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2228 if (sd_check == NULL) {
2229 dictionary->add_klass(d_hash, name, k);
2230 notice_modification();
2231 }
2232 #ifdef ASSERT
2233 sd_check = find_class(d_hash, name, dictionary);
2234 assert (sd_check != NULL, "should have entry in dictionary");
2235 // Note: there may be a placeholder entry: for circularity testing
2236 // or for parallel defines
2237 #endif
2238 SystemDictionary_lock->notify_all();
2239 }
2240 }
2241
2242
2243 // Try to find a class name using the loader constraints. The
2244 // loader constraints might know about a class that isn't fully loaded
2245 // yet and these will be ignored.
2246 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2247 Symbol* class_name, Handle class_loader, TRAPS) {
2248
2249 // First see if it has been loaded directly.
2250 // Force the protection domain to be null. (This removes protection checks.)
2251 Handle no_protection_domain;
2252 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2253 no_protection_domain, CHECK_NULL);
2254 if (klass != NULL)
2255 return klass;
2256
2257 // Now look to see if it has been loaded elsewhere, and is subject to
2258 // a loader constraint that would require this loader to return the
2259 // klass that is already loaded.
2260 if (FieldType::is_array(class_name)) {
2261 // For array classes, their Klass*s are not kept in the
2262 // constraint table. The element Klass*s are.
2263 FieldArrayInfo fd;
2264 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2265 if (t != T_OBJECT) {
2266 klass = Universe::typeArrayKlassObj(t);
2267 } else {
2268 MutexLocker mu(SystemDictionary_lock, THREAD);
2269 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2270 }
2271 // If element class already loaded, allocate array klass
2272 if (klass != NULL) {
2273 klass = klass->array_klass_or_null(fd.dimension());
2274 }
2275 } else {
2276 MutexLocker mu(SystemDictionary_lock, THREAD);
2277 // Non-array classes are easy: simply check the constraint table.
2278 klass = constraints()->find_constrained_klass(class_name, class_loader);
2279 }
2280
2281 return klass;
2282 }
2283
2284
2285 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2286 Handle class_loader1,
2287 Handle class_loader2,
2288 Thread* THREAD) {
2289 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2290 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2291
2292 Symbol* constraint_name = NULL;
2293 // Needs to be in same scope as constraint_name in case a Symbol is created and
2294 // assigned to constraint_name.
2295 FieldArrayInfo fd;
2296 if (!FieldType::is_array(class_name)) {
2297 constraint_name = class_name;
2298 } else {
2299 // For array classes, their Klass*s are not kept in the
2300 // constraint table. The element classes are.
2301 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2302 // primitive types always pass
2303 if (t != T_OBJECT) {
2304 return true;
2305 } else {
2306 constraint_name = fd.object_key();
2307 }
2308 }
2309
2310 Dictionary* dictionary1 = loader_data1->dictionary();
2311 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2312
2313 Dictionary* dictionary2 = loader_data2->dictionary();
2314 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2315
2316 {
2317 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2318 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2319 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2320 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2321 klass2, class_loader2);
2322 }
2323 }
2324
2325 // Add entry to resolution error table to record the error when the first
2326 // attempt to resolve a reference to a class has failed.
2327 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2328 Symbol* error, Symbol* message) {
2329 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2330 int index = resolution_errors()->hash_to_index(hash);
2331 {
2332 MutexLocker ml(SystemDictionary_lock, Thread::current());
2333 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2334 }
2335 }
2336
2337 // Delete a resolution error for RedefineClasses for a constant pool is going away
2338 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2339 resolution_errors()->delete_entry(pool);
2340 }
2341
2342 // Lookup resolution error table. Returns error if found, otherwise NULL.
2343 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2344 Symbol** message) {
2345 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2346 int index = resolution_errors()->hash_to_index(hash);
2347 {
2348 MutexLocker ml(SystemDictionary_lock, Thread::current());
2349 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2350 if (entry != NULL) {
2351 *message = entry->message();
2352 return entry->error();
2353 } else {
2354 return NULL;
2355 }
2356 }
2357 }
2358
2359
2360 // Signature constraints ensure that callers and callees agree about
2361 // the meaning of type names in their signatures. This routine is the
2362 // intake for constraints. It collects them from several places:
2363 //
2364 // * LinkResolver::resolve_method (if check_access is true) requires
2365 // that the resolving class (the caller) and the defining class of
2366 // the resolved method (the callee) agree on each type in the
2367 // method's signature.
2368 //
2369 // * LinkResolver::resolve_interface_method performs exactly the same
2370 // checks.
2371 //
2372 // * LinkResolver::resolve_field requires that the constant pool
2373 // attempting to link to a field agree with the field's defining
2374 // class about the type of the field signature.
2375 //
2376 // * klassVtable::initialize_vtable requires that, when a class
2377 // overrides a vtable entry allocated by a superclass, that the
2378 // overriding method (i.e., the callee) agree with the superclass
2379 // on each type in the method's signature.
2380 //
2381 // * klassItable::initialize_itable requires that, when a class fills
2382 // in its itables, for each non-abstract method installed in an
2383 // itable, the method (i.e., the callee) agree with the interface
2384 // on each type in the method's signature.
2385 //
2386 // All those methods have a boolean (check_access, checkconstraints)
2387 // which turns off the checks. This is used from specialized contexts
2388 // such as bootstrapping, dumping, and debugging.
2389 //
2390 // No direct constraint is placed between the class and its
2391 // supertypes. Constraints are only placed along linked relations
2392 // between callers and callees. When a method overrides or implements
2393 // an abstract method in a supertype (superclass or interface), the
2394 // constraints are placed as if the supertype were the caller to the
2395 // overriding method. (This works well, since callers to the
2396 // supertype have already established agreement between themselves and
2397 // the supertype.) As a result of all this, a class can disagree with
2398 // its supertype about the meaning of a type name, as long as that
2399 // class neither calls a relevant method of the supertype, nor is
2400 // called (perhaps via an override) from the supertype.
2401 //
2402 //
2403 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2404 //
2405 // Make sure all class components (including arrays) in the given
2406 // signature will be resolved to the same class in both loaders.
2407 // Returns the name of the type that failed a loader constraint check, or
2408 // NULL if no constraint failed. No exception except OOME is thrown.
2409 // Arrays are not added to the loader constraint table, their elements are.
2410 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2411 Handle loader1, Handle loader2,
2412 bool is_method, TRAPS) {
2413 // Nothing to do if loaders are the same.
2414 if (oopDesc::equals(loader1(), loader2())) {
2415 return NULL;
2416 }
2417
2418 SignatureStream sig_strm(signature, is_method);
2419 while (!sig_strm.is_done()) {
2420 if (sig_strm.is_object()) {
2421 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2422 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2423 return sig;
2424 }
2425 }
2426 sig_strm.next();
2427 }
2428 return NULL;
2429 }
2430
2431
2432 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2433 Symbol* signature,
2434 TRAPS) {
2435 methodHandle empty;
2436 assert(MethodHandles::is_signature_polymorphic(iid) &&
2437 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2438 iid != vmIntrinsics::_invokeGeneric,
2439 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2440
2441 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2442 int index = invoke_method_table()->hash_to_index(hash);
2443 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2444 methodHandle m;
2445 if (spe == NULL || spe->method() == NULL) {
2446 spe = NULL;
2447 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2448 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2449 if (!Arguments::is_interpreter_only()) {
2450 // Generate a compiled form of the MH intrinsic.
2451 AdapterHandlerLibrary::create_native_wrapper(m);
2452 // Check if have the compiled code.
2453 if (!m->has_compiled_code()) {
2454 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2455 "Out of space in CodeCache for method handle intrinsic", empty);
2456 }
2457 }
2458 // Now grab the lock. We might have to throw away the new method,
2459 // if a racing thread has managed to install one at the same time.
2460 {
2461 MutexLocker ml(SystemDictionary_lock, THREAD);
2462 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2463 if (spe == NULL)
2464 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2465 if (spe->method() == NULL)
2466 spe->set_method(m());
2467 }
2468 }
2469
2470 assert(spe != NULL && spe->method() != NULL, "");
2471 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2472 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2473 "MH intrinsic invariant");
2474 return spe->method();
2475 }
2476
2477 // Helper for unpacking the return value from linkMethod and linkCallSite.
2478 static methodHandle unpack_method_and_appendix(Handle mname,
2479 Klass* accessing_klass,
2480 objArrayHandle appendix_box,
2481 Handle* appendix_result,
2482 TRAPS) {
2483 methodHandle empty;
2484 if (mname.not_null()) {
2485 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2486 if (m != NULL) {
2487 oop appendix = appendix_box->obj_at(0);
2488 if (TraceMethodHandles) {
2489 #ifndef PRODUCT
2490 ttyLocker ttyl;
2491 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2492 m->print();
2493 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2494 tty->cr();
2495 #endif //PRODUCT
2496 }
2497 (*appendix_result) = Handle(THREAD, appendix);
2498 // the target is stored in the cpCache and if a reference to this
2499 // MemberName is dropped we need a way to make sure the
2500 // class_loader containing this method is kept alive.
2501 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2502 this_key->record_dependency(m->method_holder());
2503 return methodHandle(THREAD, m);
2504 }
2505 }
2506 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2507 return empty;
2508 }
2509
2510 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2511 Symbol* name,
2512 Symbol* signature,
2513 Klass* accessing_klass,
2514 Handle *appendix_result,
2515 Handle *method_type_result,
2516 TRAPS) {
2517 methodHandle empty;
2518 assert(THREAD->can_call_java() ,"");
2519 Handle method_type =
2520 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2521
2522 int ref_kind = JVM_REF_invokeVirtual;
2523 oop name_oop = StringTable::intern(name, CHECK_(empty));
2524 Handle name_str (THREAD, name_oop);
2525 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2526 assert(appendix_box->obj_at(0) == NULL, "");
2527
2528 // This should not happen. JDK code should take care of that.
2529 if (accessing_klass == NULL || method_type.is_null()) {
2530 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2531 }
2532
2533 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2534 JavaCallArguments args;
2535 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2536 args.push_int(ref_kind);
2537 args.push_oop(Handle(THREAD, klass->java_mirror()));
2538 args.push_oop(name_str);
2539 args.push_oop(method_type);
2540 args.push_oop(appendix_box);
2541 JavaValue result(T_OBJECT);
2542 JavaCalls::call_static(&result,
2543 SystemDictionary::MethodHandleNatives_klass(),
2544 vmSymbols::linkMethod_name(),
2545 vmSymbols::linkMethod_signature(),
2546 &args, CHECK_(empty));
2547 Handle mname(THREAD, (oop) result.get_jobject());
2548 (*method_type_result) = method_type;
2549 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2550 }
2551
2552 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2553 // We must ensure that all class loaders everywhere will reach this class, for any client.
2554 // This is a safe bet for public classes in java.lang, such as Object and String.
2555 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2556 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2557 static bool is_always_visible_class(oop mirror) {
2558 Klass* klass = java_lang_Class::as_Klass(mirror);
2559 if (klass->is_objArray_klass()) {
2560 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2561 }
2562 if (klass->is_typeArray_klass()) {
2563 return true; // primitive array
2564 }
2565 assert(klass->is_instance_klass(), "%s", klass->external_name());
2566 return klass->is_public() &&
2567 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2568 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2569 }
2570
2571
2572 // Return the Java mirror (java.lang.Class instance) for a single-character
2573 // descriptor. This result, when available, is the same as produced by the
2574 // heavier API point of the same name that takes a Symbol.
2575 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2576 return java_lang_Class::primitive_mirror(char2type(signature_char));
2577 }
2578
2579 // Find or construct the Java mirror (java.lang.Class instance) for a
2580 // for the given field type signature, as interpreted relative to the
2581 // given class loader. Handles primitives, void, references, arrays,
2582 // and all other reflectable types, except method types.
2583 // N.B. Code in reflection should use this entry point.
2584 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2585 Klass* accessing_klass,
2586 Handle class_loader,
2587 Handle protection_domain,
2588 SignatureStream::FailureMode failure_mode,
2589 TRAPS) {
2590 Handle empty;
2591
2592 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2593 "one or the other, or perhaps neither");
2594
2595 Symbol* type = signature;
2596
2597 // What we have here must be a valid field descriptor,
2598 // and all valid field descriptors are supported.
2599 // Produce the same java.lang.Class that reflection reports.
2600 if (type->utf8_length() == 1) {
2601
2602 // It's a primitive. (Void has a primitive mirror too.)
2603 char ch = (char) type->byte_at(0);
2604 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2605 return Handle(THREAD, find_java_mirror_for_type(ch));
2606
2607 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2608
2609 // It's a reference type.
2610 if (accessing_klass != NULL) {
2611 class_loader = Handle(THREAD, accessing_klass->class_loader());
2612 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2613 }
2614 Klass* constant_type_klass;
2615 if (failure_mode == SignatureStream::ReturnNull) {
2616 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2617 CHECK_(empty));
2618 } else {
2619 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2620 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2621 throw_error, CHECK_(empty));
2622 }
2623 if (constant_type_klass == NULL) {
2624 return Handle(); // report failure this way
2625 }
2626 Handle mirror(THREAD, constant_type_klass->java_mirror());
2627
2628 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2629 if (accessing_klass != NULL) {
2630 Klass* sel_klass = constant_type_klass;
2631 bool fold_type_to_class = true;
2632 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2633 fold_type_to_class, CHECK_(empty));
2634 }
2635
2636 return mirror;
2637
2638 }
2639
2640 // Fall through to an error.
2641 assert(false, "unsupported mirror syntax");
2642 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2643 }
2644
2645
2646 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2647 // signature, as interpreted relative to the given class loader.
2648 // Because of class loader constraints, all method handle usage must be
2649 // consistent with this loader.
2650 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2651 Klass* accessing_klass,
2652 TRAPS) {
2653 Handle empty;
2654 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2655 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2656 int index = invoke_method_table()->hash_to_index(hash);
2657 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2658 if (spe != NULL && spe->method_type() != NULL) {
2659 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2660 return Handle(THREAD, spe->method_type());
2661 } else if (!THREAD->can_call_java()) {
2662 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2663 return Handle(); // do not attempt from within compiler, unless it was cached
2664 }
2665
2666 Handle class_loader, protection_domain;
2667 if (accessing_klass != NULL) {
2668 class_loader = Handle(THREAD, accessing_klass->class_loader());
2669 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2670 }
2671 bool can_be_cached = true;
2672 int npts = ArgumentCount(signature).size();
2673 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2674 int arg = 0;
2675 Handle rt; // the return type from the signature
2676 ResourceMark rm(THREAD);
2677 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2678 oop mirror = NULL;
2679 if (can_be_cached) {
2680 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2681 mirror = ss.as_java_mirror(Handle(), Handle(),
2682 SignatureStream::ReturnNull, CHECK_(empty));
2683 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2684 // Fall back to accessing_klass context.
2685 can_be_cached = false;
2686 }
2687 }
2688 if (!can_be_cached) {
2689 // Resolve, throwing a real error if it doesn't work.
2690 mirror = ss.as_java_mirror(class_loader, protection_domain,
2691 SignatureStream::NCDFError, CHECK_(empty));
2692 }
2693 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2694 if (ss.at_return_type())
2695 rt = Handle(THREAD, mirror);
2696 else
2697 pts->obj_at_put(arg++, mirror);
2698
2699 // Check accessibility.
2700 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2701 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2702 mirror = NULL; // safety
2703 // Emulate ConstantPool::verify_constant_pool_resolve.
2704 bool fold_type_to_class = true;
2705 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2706 fold_type_to_class, CHECK_(empty));
2707 }
2708 }
2709 assert(arg == npts, "");
2710
2711 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2712 JavaCallArguments args(Handle(THREAD, rt()));
2713 args.push_oop(pts);
2714 JavaValue result(T_OBJECT);
2715 JavaCalls::call_static(&result,
2716 SystemDictionary::MethodHandleNatives_klass(),
2717 vmSymbols::findMethodHandleType_name(),
2718 vmSymbols::findMethodHandleType_signature(),
2719 &args, CHECK_(empty));
2720 Handle method_type(THREAD, (oop) result.get_jobject());
2721
2722 if (can_be_cached) {
2723 // We can cache this MethodType inside the JVM.
2724 MutexLocker ml(SystemDictionary_lock, THREAD);
2725 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2726 if (spe == NULL)
2727 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2728 if (spe->method_type() == NULL) {
2729 spe->set_method_type(method_type());
2730 }
2731 }
2732
2733 // report back to the caller with the MethodType
2734 return method_type;
2735 }
2736
2737 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2738 Klass* accessing_klass,
2739 TRAPS) {
2740 Handle empty;
2741 ResourceMark rm(THREAD);
2742 SignatureStream ss(signature, /*is_method=*/ false);
2743 if (!ss.is_done()) {
2744 Handle class_loader, protection_domain;
2745 if (accessing_klass != NULL) {
2746 class_loader = Handle(THREAD, accessing_klass->class_loader());
2747 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2748 }
2749 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2750 ss.next();
2751 if (ss.is_done()) {
2752 return Handle(THREAD, mirror);
2753 }
2754 }
2755 return empty;
2756 }
2757
2758 // Ask Java code to find or construct a method handle constant.
2759 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2760 int ref_kind, //e.g., JVM_REF_invokeVirtual
2761 Klass* callee,
2762 Symbol* name,
2763 Symbol* signature,
2764 TRAPS) {
2765 Handle empty;
2766 if (caller == NULL) {
2767 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2768 }
2769 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2770 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2771
2772 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2773 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2774 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2775 java_lang_invoke_MemberName::set_name (mname(), name_str());
2776 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2777 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2778
2779 if (ref_kind == JVM_REF_invokeVirtual &&
2780 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2781 // Skip resolution for public signature polymorphic methods such as
2782 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2783 // They require appendix argument which MemberName resolution doesn't handle.
2784 // There's special logic on JDK side to handle them
2785 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2786 } else {
2787 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2788 }
2789
2790 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2791 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2792
2793 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2794 JavaCallArguments args;
2795 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2796 args.push_int(ref_kind);
2797 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2798 args.push_oop(name_str);
2799 args.push_oop(type);
2800 JavaValue result(T_OBJECT);
2801 JavaCalls::call_static(&result,
2802 SystemDictionary::MethodHandleNatives_klass(),
2803 vmSymbols::linkMethodHandleConstant_name(),
2804 vmSymbols::linkMethodHandleConstant_signature(),
2805 &args, CHECK_(empty));
2806 return Handle(THREAD, (oop) result.get_jobject());
2807 }
2808
2809 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2810 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2811 int condy_index,
2812 Handle bootstrap_specifier,
2813 Symbol* name,
2814 Symbol* type,
2815 TRAPS) {
2816 Handle empty;
2817 Handle bsm, info;
2818 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2819 bsm = bootstrap_specifier;
2820 } else {
2821 assert(bootstrap_specifier->is_objArray(), "");
2822 objArrayOop args = (objArrayOop) bootstrap_specifier();
2823 assert(args->length() == 2, "");
2824 bsm = Handle(THREAD, args->obj_at(0));
2825 info = Handle(THREAD, args->obj_at(1));
2826 }
2827 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2828 "caller must supply a valid BSM");
2829
2830 // This should not happen. JDK code should take care of that.
2831 if (caller == NULL) {
2832 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2833 }
2834
2835 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2836
2837 // Resolve the constant type in the context of the caller class
2838 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2839 CHECK_(empty));
2840
2841 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2842 JavaCallArguments args;
2843 args.push_oop(Handle(THREAD, caller->java_mirror()));
2844 args.push_int(condy_index);
2845 args.push_oop(bsm);
2846 args.push_oop(constant_name);
2847 args.push_oop(type_mirror);
2848 args.push_oop(info);
2849 JavaValue result(T_OBJECT);
2850 JavaCalls::call_static(&result,
2851 SystemDictionary::MethodHandleNatives_klass(),
2852 vmSymbols::linkDynamicConstant_name(),
2853 vmSymbols::linkDynamicConstant_signature(),
2854 &args, CHECK_(empty));
2855
2856 return Handle(THREAD, (oop) result.get_jobject());
2857 }
2858
2859 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2860 // name and signature, as interpreted relative to the given class loader.
2861 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2862 int indy_index,
2863 Handle bootstrap_specifier,
2864 Symbol* name,
2865 Symbol* type,
2866 Handle *appendix_result,
2867 Handle *method_type_result,
2868 TRAPS) {
2869 methodHandle empty;
2870 Handle bsm, info;
2871 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2872 bsm = bootstrap_specifier;
2873 } else {
2874 objArrayOop args = (objArrayOop) bootstrap_specifier();
2875 assert(args->length() == 2, "");
2876 bsm = Handle(THREAD, args->obj_at(0));
2877 info = Handle(THREAD, args->obj_at(1));
2878 }
2879 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2880 "caller must supply a valid BSM");
2881
2882 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2883 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2884
2885 // This should not happen. JDK code should take care of that.
2886 if (caller == NULL || method_type.is_null()) {
2887 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2888 }
2889
2890 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2891 assert(appendix_box->obj_at(0) == NULL, "");
2892
2893 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2894 JavaCallArguments args;
2895 args.push_oop(Handle(THREAD, caller->java_mirror()));
2896 args.push_int(indy_index);
2897 args.push_oop(bsm);
2898 args.push_oop(method_name);
2899 args.push_oop(method_type);
2900 args.push_oop(info);
2901 args.push_oop(appendix_box);
2902 JavaValue result(T_OBJECT);
2903 JavaCalls::call_static(&result,
2904 SystemDictionary::MethodHandleNatives_klass(),
2905 vmSymbols::linkCallSite_name(),
2906 vmSymbols::linkCallSite_signature(),
2907 &args, CHECK_(empty));
2908 Handle mname(THREAD, (oop) result.get_jobject());
2909 (*method_type_result) = method_type;
2910 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2911 }
2912
2913 // Protection domain cache table handling
2914
2915 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2916 return _pd_cache_table->get(protection_domain);
2917 }
2918
2919 #if INCLUDE_CDS
2920 void SystemDictionary::reorder_dictionary_for_sharing() {
2921 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2922 }
2923 #endif
2924
2925 size_t SystemDictionary::count_bytes_for_buckets() {
2926 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2927 }
2928
2929 size_t SystemDictionary::count_bytes_for_table() {
2930 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2931 }
2932
2933 void SystemDictionary::copy_buckets(char* top, char* end) {
2934 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2935 }
2936
2937 void SystemDictionary::copy_table(char* top, char* end) {
2938 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2939 }
2940
2941 // ----------------------------------------------------------------------------
2942 void SystemDictionary::print_shared(outputStream *st) {
2943 shared_dictionary()->print_on(st);
2944 }
2945
2946 void SystemDictionary::print_on(outputStream *st) {
2947 if (shared_dictionary() != NULL) {
2948 st->print_cr("Shared Dictionary");
2949 shared_dictionary()->print_on(st);
2950 st->cr();
2951 }
2952
2953 GCMutexLocker mu(SystemDictionary_lock);
2954
2955 ClassLoaderDataGraph::print_dictionary(st);
2956
2957 // Placeholders
2958 placeholders()->print_on(st);
2959 st->cr();
2960
2961 // loader constraints - print under SD_lock
2962 constraints()->print_on(st);
2963 st->cr();
2964
2965 _pd_cache_table->print_on(st);
2966 st->cr();
2967 }
2968
2969 void SystemDictionary::verify() {
2970 guarantee(constraints() != NULL,
2971 "Verify of loader constraints failed");
2972 guarantee(placeholders()->number_of_entries() >= 0,
2973 "Verify of placeholders failed");
2974
2975 GCMutexLocker mu(SystemDictionary_lock);
2976
2977 // Verify dictionary
2978 ClassLoaderDataGraph::verify_dictionary();
2979
2980 placeholders()->verify();
2981
2982 // Verify constraint table
2983 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2984 constraints()->verify(placeholders());
2985
2986 _pd_cache_table->verify();
2987 }
2988
2989 void SystemDictionary::dump(outputStream *st, bool verbose) {
2990 assert_locked_or_safepoint(SystemDictionary_lock);
2991 if (verbose) {
2992 print_on(st);
2993 } else {
2994 if (shared_dictionary() != NULL) {
2995 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2996 }
2997 ClassLoaderDataGraph::print_dictionary_statistics(st);
2998 placeholders()->print_table_statistics(st, "Placeholder Table");
2999 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3000 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3001 }
3002 }
3003
3004 // Utility for dumping dictionaries.
3005 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3006 DCmdWithParser(output, heap),
3007 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3008 "BOOLEAN", false, "false") {
3009 _dcmdparser.add_dcmd_option(&_verbose);
3010 }
3011
3012 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3013 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3014 _verbose.value());
3015 VMThread::execute(&dumper);
3016 }
3017
3018 int SystemDictionaryDCmd::num_arguments() {
3019 ResourceMark rm;
3020 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3021 if (dcmd != NULL) {
3022 DCmdMark mark(dcmd);
3023 return dcmd->_dcmdparser.num_arguments();
3024 } else {
3025 return 0;
3026 }
3027 }
3028
3029 class CombineDictionariesClosure : public CLDClosure {
3030 private:
3031 Dictionary* _master_dictionary;
3032 public:
3033 CombineDictionariesClosure(Dictionary* master_dictionary) :
3034 _master_dictionary(master_dictionary) {}
3035 void do_cld(ClassLoaderData* cld) {
3036 ResourceMark rm;
3037 if (cld->is_unsafe_anonymous()) {
3038 return;
3039 }
3040 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3041 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3042 Dictionary* curr_dictionary = cld->dictionary();
3043 DictionaryEntry* p = curr_dictionary->bucket(i);
3044 while (p != NULL) {
3045 Symbol* name = p->instance_klass()->name();
3046 unsigned int d_hash = _master_dictionary->compute_hash(name);
3047 int d_index = _master_dictionary->hash_to_index(d_hash);
3048 DictionaryEntry* next = p->next();
3049 if (p->literal()->class_loader_data() != cld) {
3050 // This is an initiating class loader entry; don't use it
3051 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3052 curr_dictionary->free_entry(p);
3053 } else {
3054 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3055 curr_dictionary->unlink_entry(p);
3056 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3057 _master_dictionary->add_entry(d_index, p);
3058 }
3059 p = next;
3060 }
3061 *curr_dictionary->bucket_addr(i) = NULL;
3062 }
3063 }
3064 }
3065 };
3066
3067 // Combining platform and system loader dictionaries into boot loader dictionary.
3068 // During run time, we only have one shared dictionary.
3069 void SystemDictionary::combine_shared_dictionaries() {
3070 assert(DumpSharedSpaces, "dump time only");
3071 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3072 CombineDictionariesClosure cdc(master_dictionary);
3073 ClassLoaderDataGraph::cld_do(&cdc);
3074
3075 // These tables are no longer valid or necessary. Keeping them around will
3076 // cause SystemDictionary::verify() to fail. Let's empty them.
3077 _placeholders = new PlaceholderTable(_placeholder_table_size);
3078 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3079
3080 NOT_PRODUCT(SystemDictionary::verify());
3081 }
3082
3083 void SystemDictionary::initialize_oop_storage() {
3084 _vm_weak_oop_storage =
3085 new OopStorage("VM Weak Oop Handles",
3086 VMWeakAlloc_lock,
3087 VMWeakActive_lock);
3088 }
3089
3090 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3091 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3092 return _vm_weak_oop_storage;
3093 }