1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "gc/shared/oopStorage.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "jfr/jfrEvents.hpp"
51 #include "logging/log.hpp"
52 #include "logging/logStream.hpp"
53 #include "memory/filemap.hpp"
54 #include "memory/metaspaceClosure.hpp"
55 #include "memory/oopFactory.hpp"
56 #include "memory/resourceArea.hpp"
57 #include "oops/access.inline.hpp"
58 #include "oops/instanceKlass.hpp"
59 #include "oops/instanceRefKlass.hpp"
60 #include "oops/klass.inline.hpp"
61 #include "oops/method.inline.hpp"
62 #include "oops/methodData.hpp"
63 #include "oops/objArrayKlass.hpp"
64 #include "oops/objArrayOop.inline.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "oops/symbol.hpp"
67 #include "oops/typeArrayKlass.hpp"
68 #include "prims/jvmtiEnvBase.hpp"
69 #include "prims/resolvedMethodTable.hpp"
70 #include "prims/methodHandles.hpp"
71 #include "runtime/arguments.hpp"
72 #include "runtime/arguments_ext.hpp"
73 #include "runtime/biasedLocking.hpp"
74 #include "runtime/fieldType.hpp"
75 #include "runtime/handles.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "runtime/orderAccess.hpp"
80 #include "runtime/sharedRuntime.hpp"
81 #include "runtime/signature.hpp"
82 #include "services/classLoadingService.hpp"
83 #include "services/diagnosticCommand.hpp"
84 #include "services/threadService.hpp"
85 #include "utilities/macros.hpp"
86 #if INCLUDE_CDS
87 #include "classfile/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_checkPackageAccess = false;
112
113 // Default ProtectionDomainCacheSize value
114
115 const int defaultProtectionDomainCacheSize = 1009;
116
117 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149 }
150
151 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
152 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
153 return ClassLoaderDataGraph::find_or_create(class_loader);
154 }
155
156 // ----------------------------------------------------------------------------
157 // Parallel class loading check
158
159 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
160 if (class_loader.is_null()) return true;
161 if (AlwaysLockClassLoader) return false;
162 return java_lang_ClassLoader::parallelCapable(class_loader());
163 }
164 // ----------------------------------------------------------------------------
165 // ParallelDefineClass flag does not apply to bootclass loader
166 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
167 if (class_loader.is_null()) return false;
168 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
169 return true;
170 }
171 return false;
172 }
173
174 // Returns true if the passed class loader is the builtin application class loader
175 // or a custom system class loader. A customer system class loader can be
176 // specified via -Djava.system.class.loader.
177 bool SystemDictionary::is_system_class_loader(oop class_loader) {
178 if (class_loader == NULL) {
179 return false;
180 }
181 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
182 oopDesc::equals(class_loader, _java_system_loader));
183 }
184
185 // Returns true if the passed class loader is the platform class loader.
186 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
187 if (class_loader == NULL) {
188 return false;
189 }
190 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
191 }
192
193 // ----------------------------------------------------------------------------
194 // Resolving of classes
195
196 // Forwards to resolve_or_null
197
198 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
199 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
200 if (HAS_PENDING_EXCEPTION || klass == NULL) {
201 // can return a null klass
202 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
203 }
204 return klass;
205 }
206
207 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
208 bool throw_error,
209 Klass* klass, TRAPS) {
210 if (HAS_PENDING_EXCEPTION) {
211 // If we have a pending exception we forward it to the caller, unless throw_error is true,
212 // in which case we have to check whether the pending exception is a ClassNotFoundException,
213 // and if so convert it to a NoClassDefFoundError
214 // And chain the original ClassNotFoundException
215 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
216 ResourceMark rm(THREAD);
217 assert(klass == NULL, "Should not have result with exception pending");
218 Handle e(THREAD, PENDING_EXCEPTION);
219 CLEAR_PENDING_EXCEPTION;
220 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
221 } else {
222 return NULL;
223 }
224 }
225 // Class not found, throw appropriate error or exception depending on value of throw_error
226 if (klass == NULL) {
227 ResourceMark rm(THREAD);
228 if (throw_error) {
229 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
230 } else {
231 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
232 }
233 }
234 return klass;
235 }
236
237
238 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
239 bool throw_error, TRAPS)
240 {
241 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
242 }
243
244
245 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
246
247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
248 if (FieldType::is_array(class_name)) {
249 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
250 } else {
251 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
252 }
253 }
254
255 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
256 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
257 Handle class_loader,
258 Handle protection_domain,
259 TRAPS) {
260 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
261 if (FieldType::is_obj(class_name)) {
262 ResourceMark rm(THREAD);
263 // Ignore wrapping L and ;.
264 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
265 class_name->utf8_length() - 2, CHECK_NULL);
266 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
267 } else {
268 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
269 }
270 }
271
272 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
273 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
274 }
275
276 // Forwards to resolve_instance_class_or_null
277
278 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
279 Handle class_loader,
280 Handle protection_domain,
281 TRAPS) {
282 assert(FieldType::is_array(class_name), "must be array");
283 Klass* k = NULL;
284 FieldArrayInfo fd;
285 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
286 // of this call
287 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
288 if (t == T_OBJECT) {
289 // naked oop "k" is OK here -- we assign back into it
290 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
291 class_loader,
292 protection_domain,
293 CHECK_NULL);
294 if (k != NULL) {
295 k = k->array_klass(fd.dimension(), CHECK_NULL);
296 }
297 } else {
298 k = Universe::typeArrayKlassObj(t);
299 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
300 }
301 return k;
302 }
303
304
305 // Must be called for any super-class or super-interface resolution
306 // during class definition to allow class circularity checking
307 // super-interface callers:
308 // parse_interfaces - for defineClass & jvmtiRedefineClasses
309 // super-class callers:
310 // ClassFileParser - for defineClass & jvmtiRedefineClasses
311 // load_shared_class - while loading a class from shared archive
312 // resolve_instance_class_or_null:
313 // via: handle_parallel_super_load
314 // when resolving a class that has an existing placeholder with
315 // a saved superclass [i.e. a defineClass is currently in progress]
316 // if another thread is trying to resolve the class, it must do
317 // super-class checks on its own thread to catch class circularity
318 // This last call is critical in class circularity checking for cases
319 // where classloading is delegated to different threads and the
320 // classloader lock is released.
321 // Take the case: Base->Super->Base
322 // 1. If thread T1 tries to do a defineClass of class Base
323 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
324 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
325 // so it tries to load Super
326 // 3. If we load the class internally, or user classloader uses same thread
327 // loadClassFromxxx or defineClass via parseClassFile Super ...
328 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
329 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
330 // 3.4 calls resolve_super_or_fail Base
331 // 3.5 finds T1,Base -> throws class circularity
332 //OR 4. If T2 tries to resolve Super via defineClass Super ...
333 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
334 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
335 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
336 // 4.4 finds T2, Super -> throws class circularity
337 // Must be called, even if superclass is null, since this is
338 // where the placeholder entry is created which claims this
339 // thread is loading this class/classloader.
340 // Be careful when modifying this code: once you have run
341 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
342 // you need to find_and_remove it before returning.
343 // So be careful to not exit with a CHECK_ macro betweeen these calls.
344 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
345 Symbol* super_name,
346 Handle class_loader,
347 Handle protection_domain,
348 bool is_superclass,
349 TRAPS) {
350 assert(!FieldType::is_array(super_name), "invalid super class name");
351 #if INCLUDE_CDS
352 if (DumpSharedSpaces) {
353 // Special processing for CDS dump time.
354 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
355 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
356 if (k) {
357 return k;
358 }
359 }
360 #endif // INCLUDE_CDS
361
362 // Double-check, if child class is already loaded, just return super-class,interface
363 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
364 // dictionary.
365 // Make sure there's a placeholder for the *child* before resolving.
366 // Used as a claim that this thread is currently loading superclass/classloader
367 // Used here for ClassCircularity checks and also for heap verification
368 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
369 // Must check ClassCircularity before checking if super class is already loaded.
370 //
371 // We might not already have a placeholder if this child_name was
372 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
373 // the name of the class might not be known until the stream is actually
374 // parsed.
375 // Bugs 4643874, 4715493
376
377 ClassLoaderData* loader_data = class_loader_data(class_loader);
378 Dictionary* dictionary = loader_data->dictionary();
379 unsigned int d_hash = dictionary->compute_hash(child_name);
380 unsigned int p_hash = placeholders()->compute_hash(child_name);
381 int p_index = placeholders()->hash_to_index(p_hash);
382 // can't throw error holding a lock
383 bool child_already_loaded = false;
384 bool throw_circularity_error = false;
385 {
386 MutexLocker mu(SystemDictionary_lock, THREAD);
387 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
388 InstanceKlass* quicksuperk;
389 // to support // loading: if child done loading, just return superclass
390 // if super_name, & class_loader don't match:
391 // if initial define, SD update will give LinkageError
392 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
393 // so we don't throw an exception here.
394 // see: nsk redefclass014 & java.lang.instrument Instrument032
395 if ((childk != NULL ) && (is_superclass) &&
396 ((quicksuperk = childk->java_super()) != NULL) &&
397 ((quicksuperk->name() == super_name) &&
398 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
399 return quicksuperk;
400 } else {
401 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
402 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
403 throw_circularity_error = true;
404 }
405 }
406 if (!throw_circularity_error) {
407 // Be careful not to exit resolve_super
408 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
409 }
410 }
411 if (throw_circularity_error) {
412 ResourceMark rm(THREAD);
413 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
414 }
415
416 // java.lang.Object should have been found above
417 assert(super_name != NULL, "null super class for resolving");
418 // Resolve the super class or interface, check results on return
419 InstanceKlass* superk =
420 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
421 class_loader,
422 protection_domain,
423 THREAD);
424
425 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
426 // It is no longer necessary to keep the placeholder table alive until update_dictionary
427 // or error. GC used to walk the placeholder table as strong roots.
428 // The instanceKlass is kept alive because the class loader is on the stack,
429 // which keeps the loader_data alive, as well as all instanceKlasses in
430 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
431 {
432 MutexLocker mu(SystemDictionary_lock, THREAD);
433 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
434 SystemDictionary_lock->notify_all();
435 }
436 if (HAS_PENDING_EXCEPTION || superk == NULL) {
437 // can null superk
438 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
439 assert(k == NULL || k == superk, "must be");
440 if (k == NULL) {
441 superk = NULL;
442 }
443 }
444
445 return superk;
446 }
447
448 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
449 Handle class_loader,
450 Handle protection_domain,
451 TRAPS) {
452 if(!has_checkPackageAccess()) return;
453
454 // Now we have to call back to java to check if the initating class has access
455 JavaValue result(T_VOID);
456 LogTarget(Debug, protectiondomain) lt;
457 if (lt.is_enabled()) {
458 ResourceMark rm;
459 // Print out trace information
460 LogStream ls(lt);
461 ls.print_cr("Checking package access");
462 if (class_loader() != NULL) {
463 ls.print("class loader: ");
464 class_loader()->print_value_on(&ls);
465 } else {
466 ls.print_cr("class loader: NULL");
467 }
468 if (protection_domain() != NULL) {
469 ls.print(" protection domain: ");
470 protection_domain()->print_value_on(&ls);
471 } else {
472 ls.print_cr(" protection domain: NULL");
473 }
474 ls.print(" loading: "); klass->print_value_on(&ls);
475 ls.cr();
476 }
477
478 // This handle and the class_loader handle passed in keeps this class from
479 // being unloaded through several GC points.
480 // The class_loader handle passed in is the initiating loader.
481 Handle mirror(THREAD, klass->java_mirror());
482
483 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
484 JavaCalls::call_special(&result,
485 class_loader,
486 system_loader,
487 vmSymbols::checkPackageAccess_name(),
488 vmSymbols::class_protectiondomain_signature(),
489 mirror,
490 protection_domain,
491 THREAD);
492
493 if (HAS_PENDING_EXCEPTION) {
494 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
495 } else {
496 log_debug(protectiondomain)("granted");
497 }
498
499 if (HAS_PENDING_EXCEPTION) return;
500
501 // If no exception has been thrown, we have validated the protection domain
502 // Insert the protection domain of the initiating class into the set.
503 {
504 ClassLoaderData* loader_data = class_loader_data(class_loader);
505 Dictionary* dictionary = loader_data->dictionary();
506
507 Symbol* kn = klass->name();
508 unsigned int d_hash = dictionary->compute_hash(kn);
509
510 MutexLocker mu(SystemDictionary_lock, THREAD);
511 int d_index = dictionary->hash_to_index(d_hash);
512 dictionary->add_protection_domain(d_index, d_hash, klass,
513 protection_domain, THREAD);
514 }
515 }
516
517 // We only get here if this thread finds that another thread
518 // has already claimed the placeholder token for the current operation,
519 // but that other thread either never owned or gave up the
520 // object lock
521 // Waits on SystemDictionary_lock to indicate placeholder table updated
522 // On return, caller must recheck placeholder table state
523 //
524 // We only get here if
525 // 1) custom classLoader, i.e. not bootstrap classloader
526 // 2) custom classLoader has broken the class loader objectLock
527 // so another thread got here in parallel
528 //
529 // lockObject must be held.
530 // Complicated dance due to lock ordering:
531 // Must first release the classloader object lock to
532 // allow initial definer to complete the class definition
533 // and to avoid deadlock
534 // Reclaim classloader lock object with same original recursion count
535 // Must release SystemDictionary_lock after notify, since
536 // class loader lock must be claimed before SystemDictionary_lock
537 // to prevent deadlocks
538 //
539 // The notify allows applications that did an untimed wait() on
540 // the classloader object lock to not hang.
541 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
542 assert_lock_strong(SystemDictionary_lock);
543
544 bool calledholdinglock
545 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
546 assert(calledholdinglock,"must hold lock for notify");
547 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
548 ObjectSynchronizer::notifyall(lockObject, THREAD);
549 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
550 SystemDictionary_lock->wait();
551 SystemDictionary_lock->unlock();
552 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
553 SystemDictionary_lock->lock();
554 }
555
556 // If the class in is in the placeholder table, class loading is in progress
557 // For cases where the application changes threads to load classes, it
558 // is critical to ClassCircularity detection that we try loading
559 // the superclass on the same thread internally, so we do parallel
560 // super class loading here.
561 // This also is critical in cases where the original thread gets stalled
562 // even in non-circularity situations.
563 // Note: must call resolve_super_or_fail even if null super -
564 // to force placeholder entry creation for this class for circularity detection
565 // Caller must check for pending exception
566 // Returns non-null Klass* if other thread has completed load
567 // and we are done,
568 // If return null Klass* and no pending exception, the caller must load the class
569 InstanceKlass* SystemDictionary::handle_parallel_super_load(
570 Symbol* name, Symbol* superclassname, Handle class_loader,
571 Handle protection_domain, Handle lockObject, TRAPS) {
572
573 ClassLoaderData* loader_data = class_loader_data(class_loader);
574 Dictionary* dictionary = loader_data->dictionary();
575 unsigned int d_hash = dictionary->compute_hash(name);
576 unsigned int p_hash = placeholders()->compute_hash(name);
577 int p_index = placeholders()->hash_to_index(p_hash);
578
579 // superk is not used, resolve_super called for circularity check only
580 // This code is reached in two situations. One if this thread
581 // is loading the same class twice (e.g. ClassCircularity, or
582 // java.lang.instrument).
583 // The second is if another thread started the resolve_super first
584 // and has not yet finished.
585 // In both cases the original caller will clean up the placeholder
586 // entry on error.
587 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
588 superclassname,
589 class_loader,
590 protection_domain,
591 true,
592 CHECK_NULL);
593
594 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
595 // Serial class loaders and bootstrap classloader do wait for superclass loads
596 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
597 MutexLocker mu(SystemDictionary_lock, THREAD);
598 // Check if classloading completed while we were loading superclass or waiting
599 return find_class(d_hash, name, dictionary);
600 }
601
602 // must loop to both handle other placeholder updates
603 // and spurious notifications
604 bool super_load_in_progress = true;
605 PlaceholderEntry* placeholder;
606 while (super_load_in_progress) {
607 MutexLocker mu(SystemDictionary_lock, THREAD);
608 // Check if classloading completed while we were loading superclass or waiting
609 InstanceKlass* check = find_class(d_hash, name, dictionary);
610 if (check != NULL) {
611 // Klass is already loaded, so just return it
612 return check;
613 } else {
614 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
615 if (placeholder && placeholder->super_load_in_progress() ){
616 // We only get here if the application has released the
617 // classloader lock when another thread was in the middle of loading a
618 // superclass/superinterface for this class, and now
619 // this thread is also trying to load this class.
620 // To minimize surprises, the first thread that started to
621 // load a class should be the one to complete the loading
622 // with the classfile it initially expected.
623 // This logic has the current thread wait once it has done
624 // all the superclass/superinterface loading it can, until
625 // the original thread completes the class loading or fails
626 // If it completes we will use the resulting InstanceKlass
627 // which we will find below in the systemDictionary.
628 // We also get here for parallel bootstrap classloader
629 if (class_loader.is_null()) {
630 SystemDictionary_lock->wait();
631 } else {
632 double_lock_wait(lockObject, THREAD);
633 }
634 } else {
635 // If not in SD and not in PH, other thread's load must have failed
636 super_load_in_progress = false;
637 }
638 }
639 }
640 return NULL;
641 }
642
643 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
644 assert(event != NULL, "invariant");
645 assert(k != NULL, "invariant");
646 assert(event->should_commit(), "invariant");
647 event->set_loadedClass(k);
648 event->set_definingClassLoader(k->class_loader_data());
649 event->set_initiatingClassLoader(init_cld);
650 event->commit();
651 }
652
653
654 // Be careful when modifying this code: once you have run
655 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
656 // you need to find_and_remove it before returning.
657 // So be careful to not exit with a CHECK_ macro betweeen these calls.
658 //
659 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
660 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
661 Handle class_loader,
662 Handle protection_domain,
663 TRAPS) {
664 assert(name != NULL && !FieldType::is_array(name) &&
665 !FieldType::is_obj(name), "invalid class name");
666
667 EventClassLoad class_load_start_event;
668
669 HandleMark hm(THREAD);
670
671 // Fix for 4474172; see evaluation for more details
672 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
673 ClassLoaderData* loader_data = register_loader(class_loader);
674 Dictionary* dictionary = loader_data->dictionary();
675 unsigned int d_hash = dictionary->compute_hash(name);
676
677 // Do lookup to see if class already exist and the protection domain
678 // has the right access
679 // This call uses find which checks protection domain already matches
680 // All subsequent calls use find_class, and set has_loaded_class so that
681 // before we return a result we call out to java to check for valid protection domain
682 // to allow returning the Klass* and add it to the pd_set if it is valid
683 {
684 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
685 if (probe != NULL) return probe;
686 }
687
688 // Non-bootstrap class loaders will call out to class loader and
689 // define via jvm/jni_DefineClass which will acquire the
690 // class loader object lock to protect against multiple threads
691 // defining the class in parallel by accident.
692 // This lock must be acquired here so the waiter will find
693 // any successful result in the SystemDictionary and not attempt
694 // the define.
695 // ParallelCapable Classloaders and the bootstrap classloader
696 // do not acquire lock here.
697 bool DoObjectLock = true;
698 if (is_parallelCapable(class_loader)) {
699 DoObjectLock = false;
700 }
701
702 unsigned int p_hash = placeholders()->compute_hash(name);
703 int p_index = placeholders()->hash_to_index(p_hash);
704
705 // Class is not in SystemDictionary so we have to do loading.
706 // Make sure we are synchronized on the class loader before we proceed
707 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
708 check_loader_lock_contention(lockObject, THREAD);
709 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
710
711 // Check again (after locking) if class already exist in SystemDictionary
712 bool class_has_been_loaded = false;
713 bool super_load_in_progress = false;
714 bool havesupername = false;
715 InstanceKlass* k = NULL;
716 PlaceholderEntry* placeholder;
717 Symbol* superclassname = NULL;
718
719 assert(THREAD->can_call_java(),
720 "can not load classes with compiler thread: class=%s, classloader=%s",
721 name->as_C_string(),
722 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
723 {
724 MutexLocker mu(SystemDictionary_lock, THREAD);
725 InstanceKlass* check = find_class(d_hash, name, dictionary);
726 if (check != NULL) {
727 // InstanceKlass is already loaded, so just return it
728 class_has_been_loaded = true;
729 k = check;
730 } else {
731 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
732 if (placeholder && placeholder->super_load_in_progress()) {
733 super_load_in_progress = true;
734 if (placeholder->havesupername() == true) {
735 superclassname = placeholder->supername();
736 havesupername = true;
737 }
738 }
739 }
740 }
741
742 // If the class is in the placeholder table, class loading is in progress
743 if (super_load_in_progress && havesupername==true) {
744 k = handle_parallel_super_load(name,
745 superclassname,
746 class_loader,
747 protection_domain,
748 lockObject, THREAD);
749 if (HAS_PENDING_EXCEPTION) {
750 return NULL;
751 }
752 if (k != NULL) {
753 class_has_been_loaded = true;
754 }
755 }
756
757 bool throw_circularity_error = false;
758 if (!class_has_been_loaded) {
759 bool load_instance_added = false;
760
761 // add placeholder entry to record loading instance class
762 // Five cases:
763 // All cases need to prevent modifying bootclasssearchpath
764 // in parallel with a classload of same classname
765 // Redefineclasses uses existence of the placeholder for the duration
766 // of the class load to prevent concurrent redefinition of not completely
767 // defined classes.
768 // case 1. traditional classloaders that rely on the classloader object lock
769 // - no other need for LOAD_INSTANCE
770 // case 2. traditional classloaders that break the classloader object lock
771 // as a deadlock workaround. Detection of this case requires that
772 // this check is done while holding the classloader object lock,
773 // and that lock is still held when calling classloader's loadClass.
774 // For these classloaders, we ensure that the first requestor
775 // completes the load and other requestors wait for completion.
776 // case 3. Bootstrap classloader - don't own objectLocker
777 // This classloader supports parallelism at the classloader level,
778 // but only allows a single load of a class/classloader pair.
779 // No performance benefit and no deadlock issues.
780 // case 4. parallelCapable user level classloaders - without objectLocker
781 // Allow parallel classloading of a class/classloader pair
782
783 {
784 MutexLocker mu(SystemDictionary_lock, THREAD);
785 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
786 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
787 if (oldprobe) {
788 // only need check_seen_thread once, not on each loop
789 // 6341374 java/lang/Instrument with -Xcomp
790 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
791 throw_circularity_error = true;
792 } else {
793 // case 1: traditional: should never see load_in_progress.
794 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
795
796 // case 3: bootstrap classloader: prevent futile classloading,
797 // wait on first requestor
798 if (class_loader.is_null()) {
799 SystemDictionary_lock->wait();
800 } else {
801 // case 2: traditional with broken classloader lock. wait on first
802 // requestor.
803 double_lock_wait(lockObject, THREAD);
804 }
805 // Check if classloading completed while we were waiting
806 InstanceKlass* check = find_class(d_hash, name, dictionary);
807 if (check != NULL) {
808 // Klass is already loaded, so just return it
809 k = check;
810 class_has_been_loaded = true;
811 }
812 // check if other thread failed to load and cleaned up
813 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
814 }
815 }
816 }
817 }
818 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
819 // case 4: parallelCapable: allow competing threads to try
820 // LOAD_INSTANCE in parallel
821
822 if (!throw_circularity_error && !class_has_been_loaded) {
823 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
824 load_instance_added = true;
825 // For class loaders that do not acquire the classloader object lock,
826 // if they did not catch another thread holding LOAD_INSTANCE,
827 // need a check analogous to the acquire ObjectLocker/find_class
828 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
829 // one final check if the load has already completed
830 // class loaders holding the ObjectLock shouldn't find the class here
831 InstanceKlass* check = find_class(d_hash, name, dictionary);
832 if (check != NULL) {
833 // Klass is already loaded, so return it after checking/adding protection domain
834 k = check;
835 class_has_been_loaded = true;
836 }
837 }
838 }
839
840 // must throw error outside of owning lock
841 if (throw_circularity_error) {
842 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
843 ResourceMark rm(THREAD);
844 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
845 }
846
847 if (!class_has_been_loaded) {
848
849 // Do actual loading
850 k = load_instance_class(name, class_loader, THREAD);
851
852 // If everything was OK (no exceptions, no null return value), and
853 // class_loader is NOT the defining loader, do a little more bookkeeping.
854 if (!HAS_PENDING_EXCEPTION && k != NULL &&
855 !oopDesc::equals(k->class_loader(), class_loader())) {
856
857 check_constraints(d_hash, k, class_loader, false, THREAD);
858
859 // Need to check for a PENDING_EXCEPTION again; check_constraints
860 // can throw and doesn't use the CHECK macro.
861 if (!HAS_PENDING_EXCEPTION) {
862 { // Grabbing the Compile_lock prevents systemDictionary updates
863 // during compilations.
864 MutexLocker mu(Compile_lock, THREAD);
865 update_dictionary(d_hash, p_index, p_hash,
866 k, class_loader, THREAD);
867 }
868
869 if (JvmtiExport::should_post_class_load()) {
870 Thread *thread = THREAD;
871 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
872 JvmtiExport::post_class_load((JavaThread *) thread, k);
873 }
874 }
875 }
876 } // load_instance_class
877
878 if (load_instance_added == true) {
879 // clean up placeholder entries for LOAD_INSTANCE success or error
880 // This brackets the SystemDictionary updates for both defining
881 // and initiating loaders
882 MutexLocker mu(SystemDictionary_lock, THREAD);
883 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
884 SystemDictionary_lock->notify_all();
885 }
886 }
887
888 if (HAS_PENDING_EXCEPTION || k == NULL) {
889 return NULL;
890 }
891 if (class_load_start_event.should_commit()) {
892 post_class_load_event(&class_load_start_event, k, loader_data);
893 }
894 #ifdef ASSERT
895 {
896 ClassLoaderData* loader_data = k->class_loader_data();
897 MutexLocker mu(SystemDictionary_lock, THREAD);
898 InstanceKlass* kk = find_class(name, loader_data);
899 assert(kk == k, "should be present in dictionary");
900 }
901 #endif
902
903 // return if the protection domain in NULL
904 if (protection_domain() == NULL) return k;
905
906 // Check the protection domain has the right access
907 if (dictionary->is_valid_protection_domain(d_hash, name,
908 protection_domain)) {
909 return k;
910 }
911
912 // Verify protection domain. If it fails an exception is thrown
913 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
914
915 return k;
916 }
917
918
919 // This routine does not lock the system dictionary.
920 //
921 // Since readers don't hold a lock, we must make sure that system
922 // dictionary entries are only removed at a safepoint (when only one
923 // thread is running), and are added to in a safe way (all links must
924 // be updated in an MT-safe manner).
925 //
926 // Callers should be aware that an entry could be added just after
927 // _dictionary->bucket(index) is read here, so the caller will not see
928 // the new entry.
929
930 Klass* SystemDictionary::find(Symbol* class_name,
931 Handle class_loader,
932 Handle protection_domain,
933 TRAPS) {
934
935 // The result of this call should be consistent with the result
936 // of the call to resolve_instance_class_or_null().
937 // See evaluation 6790209 and 4474172 for more details.
938 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
939 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
940
941 if (loader_data == NULL) {
942 // If the ClassLoaderData has not been setup,
943 // then the class loader has no entries in the dictionary.
944 return NULL;
945 }
946
947 Dictionary* dictionary = loader_data->dictionary();
948 unsigned int d_hash = dictionary->compute_hash(class_name);
949 return dictionary->find(d_hash, class_name,
950 protection_domain);
951 }
952
953
954 // Look for a loaded instance or array klass by name. Do not do any loading.
955 // return NULL in case of error.
956 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
957 Handle class_loader,
958 Handle protection_domain,
959 TRAPS) {
960 Klass* k = NULL;
961 assert(class_name != NULL, "class name must be non NULL");
962
963 if (FieldType::is_array(class_name)) {
964 // The name refers to an array. Parse the name.
965 // dimension and object_key in FieldArrayInfo are assigned as a
966 // side-effect of this call
967 FieldArrayInfo fd;
968 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
969 if (t != T_OBJECT) {
970 k = Universe::typeArrayKlassObj(t);
971 } else {
972 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
973 }
974 if (k != NULL) {
975 k = k->array_klass_or_null(fd.dimension());
976 }
977 } else {
978 k = find(class_name, class_loader, protection_domain, THREAD);
979 }
980 return k;
981 }
982
983 // Note: this method is much like resolve_from_stream, but
984 // does not publish the classes via the SystemDictionary.
985 // Handles unsafe_DefineAnonymousClass and redefineclasses
986 // RedefinedClasses do not add to the class hierarchy
987 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
988 Handle class_loader,
989 Handle protection_domain,
990 ClassFileStream* st,
991 const InstanceKlass* unsafe_anonymous_host,
992 GrowableArray<Handle>* cp_patches,
993 TRAPS) {
994
995 EventClassLoad class_load_start_event;
996
997 ClassLoaderData* loader_data;
998 if (unsafe_anonymous_host != NULL) {
999 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1000 // as the unsafe_anonymous_host
1001 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1002 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1003 } else {
1004 loader_data = ClassLoaderData::class_loader_data(class_loader());
1005 }
1006
1007 assert(st != NULL, "invariant");
1008 assert(st->need_verify(), "invariant");
1009
1010 // Parse stream and create a klass.
1011 // Note that we do this even though this klass might
1012 // already be present in the SystemDictionary, otherwise we would not
1013 // throw potential ClassFormatErrors.
1014
1015 InstanceKlass* k = KlassFactory::create_from_stream(st,
1016 class_name,
1017 loader_data,
1018 protection_domain,
1019 unsafe_anonymous_host,
1020 cp_patches,
1021 CHECK_NULL);
1022
1023 if (unsafe_anonymous_host != NULL && k != NULL) {
1024 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1025 // so that they can be unloaded when the mirror is no longer referenced.
1026 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1027
1028 {
1029 MutexLocker mu_r(Compile_lock, THREAD);
1030
1031 // Add to class hierarchy, initialize vtables, and do possible
1032 // deoptimizations.
1033 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1034
1035 // But, do not add to dictionary.
1036
1037 // compiled code dependencies need to be validated anyway
1038 notice_modification();
1039 }
1040
1041 // Rewrite and patch constant pool here.
1042 k->link_class(CHECK_NULL);
1043 if (cp_patches != NULL) {
1044 k->constants()->patch_resolved_references(cp_patches);
1045 }
1046
1047 // If it's anonymous, initialize it now, since nobody else will.
1048 k->eager_initialize(CHECK_NULL);
1049
1050 // notify jvmti
1051 if (JvmtiExport::should_post_class_load()) {
1052 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1053 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1054 }
1055 if (class_load_start_event.should_commit()) {
1056 post_class_load_event(&class_load_start_event, k, loader_data);
1057 }
1058 }
1059 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1060 "cp_patches only found with unsafe_anonymous_host");
1061
1062 return k;
1063 }
1064
1065 // Add a klass to the system from a stream (called by jni_DefineClass and
1066 // JVM_DefineClass).
1067 // Note: class_name can be NULL. In that case we do not know the name of
1068 // the class until we have parsed the stream.
1069
1070 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1071 Handle class_loader,
1072 Handle protection_domain,
1073 ClassFileStream* st,
1074 TRAPS) {
1075
1076 HandleMark hm(THREAD);
1077
1078 // Classloaders that support parallelism, e.g. bootstrap classloader,
1079 // do not acquire lock here
1080 bool DoObjectLock = true;
1081 if (is_parallelCapable(class_loader)) {
1082 DoObjectLock = false;
1083 }
1084
1085 ClassLoaderData* loader_data = register_loader(class_loader);
1086
1087 // Make sure we are synchronized on the class loader before we proceed
1088 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1089 check_loader_lock_contention(lockObject, THREAD);
1090 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1091
1092 assert(st != NULL, "invariant");
1093
1094 // Parse the stream and create a klass.
1095 // Note that we do this even though this klass might
1096 // already be present in the SystemDictionary, otherwise we would not
1097 // throw potential ClassFormatErrors.
1098 InstanceKlass* k = NULL;
1099
1100 #if INCLUDE_CDS
1101 if (!DumpSharedSpaces) {
1102 k = SystemDictionaryShared::lookup_from_stream(class_name,
1103 class_loader,
1104 protection_domain,
1105 st,
1106 CHECK_NULL);
1107 }
1108 #endif
1109
1110 if (k == NULL) {
1111 if (st->buffer() == NULL) {
1112 return NULL;
1113 }
1114 k = KlassFactory::create_from_stream(st,
1115 class_name,
1116 loader_data,
1117 protection_domain,
1118 NULL, // unsafe_anonymous_host
1119 NULL, // cp_patches
1120 CHECK_NULL);
1121 }
1122
1123 assert(k != NULL, "no klass created");
1124 Symbol* h_name = k->name();
1125 assert(class_name == NULL || class_name == h_name, "name mismatch");
1126
1127 // Add class just loaded
1128 // If a class loader supports parallel classloading handle parallel define requests
1129 // find_or_define_instance_class may return a different InstanceKlass
1130 if (is_parallelCapable(class_loader)) {
1131 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1132 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1133 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1134 assert(defined_k != NULL, "Should have a klass if there's no exception");
1135 loader_data->add_to_deallocate_list(k);
1136 k = defined_k;
1137 }
1138 } else {
1139 define_instance_class(k, THREAD);
1140 }
1141
1142 // If defining the class throws an exception register 'k' for cleanup.
1143 if (HAS_PENDING_EXCEPTION) {
1144 assert(k != NULL, "Must have an instance klass here!");
1145 loader_data->add_to_deallocate_list(k);
1146 return NULL;
1147 }
1148
1149 // Make sure we have an entry in the SystemDictionary on success
1150 debug_only( {
1151 MutexLocker mu(SystemDictionary_lock, THREAD);
1152
1153 Klass* check = find_class(h_name, k->class_loader_data());
1154 assert(check == k, "should be present in the dictionary");
1155 } );
1156
1157 return k;
1158 }
1159
1160 #if INCLUDE_CDS
1161 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1162 int number_of_entries) {
1163 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
1164 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1165 "bad shared dictionary size.");
1166 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1167 _shared_dictionary_size, t, number_of_entries,
1168 false /* explicitly set _resizable to false */);
1169 }
1170
1171
1172 // If there is a shared dictionary, then find the entry for the
1173 // given shared system class, if any.
1174
1175 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1176 if (shared_dictionary() != NULL) {
1177 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1178 int d_index = shared_dictionary()->hash_to_index(d_hash);
1179
1180 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1181 } else {
1182 return NULL;
1183 }
1184 }
1185
1186
1187 // Load a class from the shared spaces (found through the shared system
1188 // dictionary). Force the superclass and all interfaces to be loaded.
1189 // Update the class definition to include sibling classes and no
1190 // subclasses (yet). [Classes in the shared space are not part of the
1191 // object hierarchy until loaded.]
1192
1193 InstanceKlass* SystemDictionary::load_shared_class(
1194 Symbol* class_name, Handle class_loader, TRAPS) {
1195 InstanceKlass* ik = find_shared_class(class_name);
1196 // Make sure we only return the boot class for the NULL classloader.
1197 if (ik != NULL &&
1198 ik->is_shared_boot_class() && class_loader.is_null()) {
1199 Handle protection_domain;
1200 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1201 }
1202 return NULL;
1203 }
1204
1205 // Check if a shared class can be loaded by the specific classloader:
1206 //
1207 // NULL classloader:
1208 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1209 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1210 // be defined in an unnamed module.
1211 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1212 InstanceKlass* ik,
1213 Handle class_loader, TRAPS) {
1214 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1215 "Cannot use sharing if java.base is patched");
1216 ResourceMark rm;
1217 int path_index = ik->shared_classpath_index();
1218 ClassLoaderData* loader_data = class_loader_data(class_loader);
1219 if (path_index < 0) {
1220 // path_index < 0 indicates that the class is intended for a custom loader
1221 // and should not be loaded by boot/platform/app loaders
1222 if (loader_data->is_builtin_class_loader_data()) {
1223 return false;
1224 } else {
1225 return true;
1226 }
1227 }
1228 SharedClassPathEntry* ent =
1229 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1230 if (!Universe::is_module_initialized()) {
1231 assert(ent != NULL && ent->is_modules_image(),
1232 "Loading non-bootstrap classes before the module system is initialized");
1233 assert(class_loader.is_null(), "sanity");
1234 return true;
1235 }
1236 // Get the pkg_entry from the classloader
1237 TempNewSymbol pkg_name = NULL;
1238 PackageEntry* pkg_entry = NULL;
1239 ModuleEntry* mod_entry = NULL;
1240 const char* pkg_string = NULL;
1241 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1242 if (pkg_name != NULL) {
1243 pkg_string = pkg_name->as_C_string();
1244 if (loader_data != NULL) {
1245 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1246 }
1247 if (pkg_entry != NULL) {
1248 mod_entry = pkg_entry->module();
1249 }
1250 }
1251
1252 // If the archived class is from a module that has been patched at runtime,
1253 // the class cannot be loaded from the archive.
1254 if (mod_entry != NULL && mod_entry->is_patched()) {
1255 return false;
1256 }
1257
1258 if (class_loader.is_null()) {
1259 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1260 // The NULL classloader can load archived class originated from the
1261 // "modules" jimage and the -Xbootclasspath/a. For class from the
1262 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1263 // by the NULL classloader.
1264 if (mod_entry != NULL) {
1265 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1266 // ModuleEntry's location agrees with the archived class' origination.
1267 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1268 return true; // Module class from the "module" jimage
1269 }
1270 }
1271
1272 // If the archived class is not from the "module" jimage, the class can be
1273 // loaded by the NULL classloader if
1274 //
1275 // 1. the class is from the unamed package
1276 // 2. or, the class is not from a module defined in the NULL classloader
1277 // 3. or, the class is from an unamed module
1278 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1279 // the class is from the -Xbootclasspath/a
1280 if (pkg_string == NULL ||
1281 pkg_entry == NULL ||
1282 pkg_entry->in_unnamed_module()) {
1283 assert(mod_entry == NULL ||
1284 mod_entry == loader_data->unnamed_module(),
1285 "the unnamed module is not defined in the classloader");
1286 return true;
1287 }
1288 }
1289 return false;
1290 } else {
1291 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1292 ik, class_loader, pkg_string, pkg_name,
1293 pkg_entry, mod_entry, CHECK_(false));
1294 return res;
1295 }
1296 }
1297
1298 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1299 Handle class_loader,
1300 Handle protection_domain, TRAPS) {
1301
1302 if (ik != NULL) {
1303 Symbol* class_name = ik->name();
1304
1305 bool visible = is_shared_class_visible(
1306 class_name, ik, class_loader, CHECK_NULL);
1307 if (!visible) {
1308 return NULL;
1309 }
1310
1311 // Resolve the superclass and interfaces. They must be the same
1312 // as in dump time, because the layout of <ik> depends on
1313 // the specific layout of ik->super() and ik->local_interfaces().
1314 //
1315 // If unexpected superclass or interfaces are found, we cannot
1316 // load <ik> from the shared archive.
1317
1318 if (ik->super() != NULL) {
1319 Symbol* cn = ik->super()->name();
1320 Klass *s = resolve_super_or_fail(class_name, cn,
1321 class_loader, protection_domain, true, CHECK_NULL);
1322 if (s != ik->super()) {
1323 // The dynamically resolved super class is not the same as the one we used during dump time,
1324 // so we cannot use ik.
1325 return NULL;
1326 } else {
1327 assert(s->is_shared(), "must be");
1328 }
1329 }
1330
1331 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1332 int num_interfaces = interfaces->length();
1333 for (int index = 0; index < num_interfaces; index++) {
1334 InstanceKlass* k = interfaces->at(index);
1335 Symbol* name = k->name();
1336 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1337 if (k != i) {
1338 // The dynamically resolved interface class is not the same as the one we used during dump time,
1339 // so we cannot use ik.
1340 return NULL;
1341 } else {
1342 assert(i->is_shared(), "must be");
1343 }
1344 }
1345
1346 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1347 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1348 if (new_ik != NULL) {
1349 // The class is changed by CFLH. Return the new class. The shared class is
1350 // not used.
1351 return new_ik;
1352 }
1353
1354 // Adjust methods to recover missing data. They need addresses for
1355 // interpreter entry points and their default native method address
1356 // must be reset.
1357
1358 // Updating methods must be done under a lock so multiple
1359 // threads don't update these in parallel
1360 //
1361 // Shared classes are all currently loaded by either the bootstrap or
1362 // internal parallel class loaders, so this will never cause a deadlock
1363 // on a custom class loader lock.
1364
1365 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1366 {
1367 HandleMark hm(THREAD);
1368 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1369 check_loader_lock_contention(lockObject, THREAD);
1370 ObjectLocker ol(lockObject, THREAD, true);
1371 // prohibited package check assumes all classes loaded from archive call
1372 // restore_unshareable_info which calls ik->set_package()
1373 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1374 }
1375
1376 ik->print_class_load_logging(loader_data, NULL, NULL);
1377
1378 // For boot loader, ensure that GetSystemPackage knows that a class in this
1379 // package was loaded.
1380 if (class_loader.is_null()) {
1381 int path_index = ik->shared_classpath_index();
1382 ResourceMark rm;
1383 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1384 }
1385
1386 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1387 // Only dump the classes that can be stored into CDS archive
1388 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1389 ResourceMark rm(THREAD);
1390 classlist_file->print_cr("%s", ik->name()->as_C_string());
1391 classlist_file->flush();
1392 }
1393 }
1394
1395 // notify a class loaded from shared object
1396 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1397
1398 ik->set_has_passed_fingerprint_check(false);
1399 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1400 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1401 uint64_t cds_fp = ik->get_stored_fingerprint();
1402 if (aot_fp != 0 && aot_fp == cds_fp) {
1403 // This class matches with a class saved in an AOT library
1404 ik->set_has_passed_fingerprint_check(true);
1405 } else {
1406 ResourceMark rm;
1407 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1408 }
1409 }
1410 }
1411 return ik;
1412 }
1413
1414 void SystemDictionary::clear_invoke_method_table() {
1415 SymbolPropertyEntry* spe = NULL;
1416 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1417 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1418 while (p != NULL) {
1419 spe = p;
1420 p = p->next();
1421 _invoke_method_table->free_entry(spe);
1422 }
1423 }
1424 }
1425 #endif // INCLUDE_CDS
1426
1427 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1428
1429 if (class_loader.is_null()) {
1430 ResourceMark rm;
1431 PackageEntry* pkg_entry = NULL;
1432 bool search_only_bootloader_append = false;
1433 ClassLoaderData *loader_data = class_loader_data(class_loader);
1434
1435 // Find the package in the boot loader's package entry table.
1436 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1437 if (pkg_name != NULL) {
1438 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1439 }
1440
1441 // Prior to attempting to load the class, enforce the boot loader's
1442 // visibility boundaries.
1443 if (!Universe::is_module_initialized()) {
1444 // During bootstrapping, prior to module initialization, any
1445 // class attempting to be loaded must be checked against the
1446 // java.base packages in the boot loader's PackageEntryTable.
1447 // No class outside of java.base is allowed to be loaded during
1448 // this bootstrapping window.
1449 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1450 // Class is either in the unnamed package or in
1451 // a named package within the unnamed module. Either
1452 // case is outside of java.base, do not attempt to
1453 // load the class post java.base definition. If
1454 // java.base has not been defined, let the class load
1455 // and its package will be checked later by
1456 // ModuleEntryTable::verify_javabase_packages.
1457 if (ModuleEntryTable::javabase_defined()) {
1458 return NULL;
1459 }
1460 } else {
1461 // Check that the class' package is defined within java.base.
1462 ModuleEntry* mod_entry = pkg_entry->module();
1463 Symbol* mod_entry_name = mod_entry->name();
1464 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1465 return NULL;
1466 }
1467 }
1468 } else {
1469 // After the module system has been initialized, check if the class'
1470 // package is in a module defined to the boot loader.
1471 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1472 // Class is either in the unnamed package, in a named package
1473 // within a module not defined to the boot loader or in a
1474 // a named package within the unnamed module. In all cases,
1475 // limit visibility to search for the class only in the boot
1476 // loader's append path.
1477 search_only_bootloader_append = true;
1478 }
1479 }
1480
1481 // Prior to bootstrapping's module initialization, never load a class outside
1482 // of the boot loader's module path
1483 assert(Universe::is_module_initialized() ||
1484 !search_only_bootloader_append,
1485 "Attempt to load a class outside of boot loader's module path");
1486
1487 // Search the shared system dictionary for classes preloaded into the
1488 // shared spaces.
1489 InstanceKlass* k = NULL;
1490 {
1491 #if INCLUDE_CDS
1492 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1493 k = load_shared_class(class_name, class_loader, THREAD);
1494 #endif
1495 }
1496
1497 if (k == NULL) {
1498 // Use VM class loader
1499 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1500 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1501 }
1502
1503 // find_or_define_instance_class may return a different InstanceKlass
1504 if (k != NULL) {
1505 InstanceKlass* defined_k =
1506 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1507 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1508 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1509 assert(defined_k != NULL, "Should have a klass if there's no exception");
1510 loader_data->add_to_deallocate_list(k);
1511 k = defined_k;
1512 } else if (HAS_PENDING_EXCEPTION) {
1513 loader_data->add_to_deallocate_list(k);
1514 return NULL;
1515 }
1516 }
1517 return k;
1518 } else {
1519 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1520 ResourceMark rm(THREAD);
1521
1522 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1523 JavaThread* jt = (JavaThread*) THREAD;
1524
1525 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1526 ClassLoader::perf_app_classload_selftime(),
1527 ClassLoader::perf_app_classload_count(),
1528 jt->get_thread_stat()->perf_recursion_counts_addr(),
1529 jt->get_thread_stat()->perf_timers_addr(),
1530 PerfClassTraceTime::CLASS_LOAD);
1531
1532 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1533 // Translate to external class name format, i.e., convert '/' chars to '.'
1534 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1535
1536 JavaValue result(T_OBJECT);
1537
1538 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1539
1540 // Call public unsynchronized loadClass(String) directly for all class loaders.
1541 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1542 // acquire a class-name based lock rather than the class loader object lock.
1543 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1544 JavaCalls::call_virtual(&result,
1545 class_loader,
1546 spec_klass,
1547 vmSymbols::loadClass_name(),
1548 vmSymbols::string_class_signature(),
1549 string,
1550 CHECK_NULL);
1551
1552 assert(result.get_type() == T_OBJECT, "just checking");
1553 oop obj = (oop) result.get_jobject();
1554
1555 // Primitive classes return null since forName() can not be
1556 // used to obtain any of the Class objects representing primitives or void
1557 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1558 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1559 // For user defined Java class loaders, check that the name returned is
1560 // the same as that requested. This check is done for the bootstrap
1561 // loader when parsing the class file.
1562 if (class_name == k->name()) {
1563 return k;
1564 }
1565 }
1566 // Class is not found or has the wrong name, return NULL
1567 return NULL;
1568 }
1569 }
1570
1571 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1572 EventClassDefine event;
1573 if (event.should_commit()) {
1574 event.set_definedClass(k);
1575 event.set_definingClassLoader(def_cld);
1576 event.commit();
1577 }
1578 }
1579
1580 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1581
1582 HandleMark hm(THREAD);
1583 ClassLoaderData* loader_data = k->class_loader_data();
1584 Handle class_loader_h(THREAD, loader_data->class_loader());
1585
1586 // for bootstrap and other parallel classloaders don't acquire lock,
1587 // use placeholder token
1588 // If a parallelCapable class loader calls define_instance_class instead of
1589 // find_or_define_instance_class to get here, we have a timing
1590 // hole with systemDictionary updates and check_constraints
1591 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1592 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1593 compute_loader_lock_object(class_loader_h, THREAD)),
1594 "define called without lock");
1595 }
1596
1597 // Check class-loading constraints. Throw exception if violation is detected.
1598 // Grabs and releases SystemDictionary_lock
1599 // The check_constraints/find_class call and update_dictionary sequence
1600 // must be "atomic" for a specific class/classloader pair so we never
1601 // define two different instanceKlasses for that class/classloader pair.
1602 // Existing classloaders will call define_instance_class with the
1603 // classloader lock held
1604 // Parallel classloaders will call find_or_define_instance_class
1605 // which will require a token to perform the define class
1606 Symbol* name_h = k->name();
1607 Dictionary* dictionary = loader_data->dictionary();
1608 unsigned int d_hash = dictionary->compute_hash(name_h);
1609 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1610
1611 // Register class just loaded with class loader (placed in Vector)
1612 // Note we do this before updating the dictionary, as this can
1613 // fail with an OutOfMemoryError (if it does, we will *not* put this
1614 // class in the dictionary and will not update the class hierarchy).
1615 // JVMTI FollowReferences needs to find the classes this way.
1616 if (k->class_loader() != NULL) {
1617 methodHandle m(THREAD, Universe::loader_addClass_method());
1618 JavaValue result(T_VOID);
1619 JavaCallArguments args(class_loader_h);
1620 args.push_oop(Handle(THREAD, k->java_mirror()));
1621 JavaCalls::call(&result, m, &args, CHECK);
1622 }
1623
1624 // Add the new class. We need recompile lock during update of CHA.
1625 {
1626 unsigned int p_hash = placeholders()->compute_hash(name_h);
1627 int p_index = placeholders()->hash_to_index(p_hash);
1628
1629 MutexLocker mu_r(Compile_lock, THREAD);
1630
1631 // Add to class hierarchy, initialize vtables, and do possible
1632 // deoptimizations.
1633 add_to_hierarchy(k, CHECK); // No exception, but can block
1634
1635 // Add to systemDictionary - so other classes can see it.
1636 // Grabs and releases SystemDictionary_lock
1637 update_dictionary(d_hash, p_index, p_hash,
1638 k, class_loader_h, THREAD);
1639 }
1640 k->eager_initialize(THREAD);
1641
1642 // notify jvmti
1643 if (JvmtiExport::should_post_class_load()) {
1644 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1645 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1646
1647 }
1648 post_class_define_event(k, loader_data);
1649 }
1650
1651 // Support parallel classloading
1652 // All parallel class loaders, including bootstrap classloader
1653 // lock a placeholder entry for this class/class_loader pair
1654 // to allow parallel defines of different classes for this class loader
1655 // With AllowParallelDefine flag==true, in case they do not synchronize around
1656 // FindLoadedClass/DefineClass, calls, we check for parallel
1657 // loading for them, wait if a defineClass is in progress
1658 // and return the initial requestor's results
1659 // This flag does not apply to the bootstrap classloader.
1660 // With AllowParallelDefine flag==false, call through to define_instance_class
1661 // which will throw LinkageError: duplicate class definition.
1662 // False is the requested default.
1663 // For better performance, the class loaders should synchronize
1664 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1665 // potentially waste time reading and parsing the bytestream.
1666 // Note: VM callers should ensure consistency of k/class_name,class_loader
1667 // Be careful when modifying this code: once you have run
1668 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1669 // you need to find_and_remove it before returning.
1670 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1671 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1672 InstanceKlass* k, TRAPS) {
1673
1674 Symbol* name_h = k->name(); // passed in class_name may be null
1675 ClassLoaderData* loader_data = class_loader_data(class_loader);
1676 Dictionary* dictionary = loader_data->dictionary();
1677
1678 unsigned int d_hash = dictionary->compute_hash(name_h);
1679
1680 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1681 unsigned int p_hash = placeholders()->compute_hash(name_h);
1682 int p_index = placeholders()->hash_to_index(p_hash);
1683 PlaceholderEntry* probe;
1684
1685 {
1686 MutexLocker mu(SystemDictionary_lock, THREAD);
1687 // First check if class already defined
1688 if (is_parallelDefine(class_loader)) {
1689 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1690 if (check != NULL) {
1691 return check;
1692 }
1693 }
1694
1695 // Acquire define token for this class/classloader
1696 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1697 // Wait if another thread defining in parallel
1698 // All threads wait - even those that will throw duplicate class: otherwise
1699 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1700 // if other thread has not finished updating dictionary
1701 while (probe->definer() != NULL) {
1702 SystemDictionary_lock->wait();
1703 }
1704 // Only special cases allow parallel defines and can use other thread's results
1705 // Other cases fall through, and may run into duplicate defines
1706 // caught by finding an entry in the SystemDictionary
1707 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1708 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1709 SystemDictionary_lock->notify_all();
1710 #ifdef ASSERT
1711 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1712 assert(check != NULL, "definer missed recording success");
1713 #endif
1714 return probe->instance_klass();
1715 } else {
1716 // This thread will define the class (even if earlier thread tried and had an error)
1717 probe->set_definer(THREAD);
1718 }
1719 }
1720
1721 define_instance_class(k, THREAD);
1722
1723 Handle linkage_exception = Handle(); // null handle
1724
1725 // definer must notify any waiting threads
1726 {
1727 MutexLocker mu(SystemDictionary_lock, THREAD);
1728 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1729 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1730 if (probe != NULL) {
1731 if (HAS_PENDING_EXCEPTION) {
1732 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1733 CLEAR_PENDING_EXCEPTION;
1734 } else {
1735 probe->set_instance_klass(k);
1736 }
1737 probe->set_definer(NULL);
1738 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1739 SystemDictionary_lock->notify_all();
1740 }
1741 }
1742
1743 // Can't throw exception while holding lock due to rank ordering
1744 if (linkage_exception() != NULL) {
1745 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1746 }
1747
1748 return k;
1749 }
1750
1751 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1752 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1753 if (class_loader.is_null()) {
1754 return Handle(THREAD, _system_loader_lock_obj);
1755 } else {
1756 return class_loader;
1757 }
1758 }
1759
1760 // This method is added to check how often we have to wait to grab loader
1761 // lock. The results are being recorded in the performance counters defined in
1762 // ClassLoader::_sync_systemLoaderLockContentionRate and
1763 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1764 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1765 if (!UsePerfData) {
1766 return;
1767 }
1768
1769 assert(!loader_lock.is_null(), "NULL lock object");
1770
1771 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1772 == ObjectSynchronizer::owner_other) {
1773 // contention will likely happen, so increment the corresponding
1774 // contention counter.
1775 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1776 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1777 } else {
1778 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1779 }
1780 }
1781 }
1782
1783 // ----------------------------------------------------------------------------
1784 // Lookup
1785
1786 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1787 Symbol* class_name,
1788 Dictionary* dictionary) {
1789 assert_locked_or_safepoint(SystemDictionary_lock);
1790 int index = dictionary->hash_to_index(hash);
1791 return dictionary->find_class(index, hash, class_name);
1792 }
1793
1794
1795 // Basic find on classes in the midst of being loaded
1796 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1797 ClassLoaderData* loader_data) {
1798 assert_locked_or_safepoint(SystemDictionary_lock);
1799 unsigned int p_hash = placeholders()->compute_hash(class_name);
1800 int p_index = placeholders()->hash_to_index(p_hash);
1801 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1802 }
1803
1804
1805 // Used for assertions and verification only
1806 // Precalculating the hash and index is an optimization because there are many lookups
1807 // before adding the class.
1808 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1809 assert_locked_or_safepoint(SystemDictionary_lock);
1810 #ifndef ASSERT
1811 guarantee(VerifyBeforeGC ||
1812 VerifyDuringGC ||
1813 VerifyBeforeExit ||
1814 VerifyDuringStartup ||
1815 VerifyAfterGC, "too expensive");
1816 #endif
1817
1818 Dictionary* dictionary = loader_data->dictionary();
1819 unsigned int d_hash = dictionary->compute_hash(class_name);
1820 return find_class(d_hash, class_name, dictionary);
1821 }
1822
1823
1824 // ----------------------------------------------------------------------------
1825 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1826 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1827 // before a new class is used.
1828
1829 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1830 assert(k != NULL, "just checking");
1831 assert_locked_or_safepoint(Compile_lock);
1832
1833 // Link into hierachy. Make sure the vtables are initialized before linking into
1834 k->append_to_sibling_list(); // add to superklass/sibling list
1835 k->process_interfaces(THREAD); // handle all "implements" declarations
1836 k->set_init_state(InstanceKlass::loaded);
1837 // Now flush all code that depended on old class hierarchy.
1838 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1839 // Also, first reinitialize vtable because it may have gotten out of synch
1840 // while the new class wasn't connected to the class hierarchy.
1841 CodeCache::flush_dependents_on(k);
1842 }
1843
1844 // ----------------------------------------------------------------------------
1845 // GC support
1846
1847 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1848 // Note: anonymous classes are not in the SD.
1849 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1850 bool do_cleaning) {
1851
1852 bool unloading_occurred;
1853 {
1854 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1855
1856 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1857 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1858 if (unloading_occurred) {
1859 ClassLoaderDataGraph::clean_module_and_package_info();
1860 }
1861 }
1862
1863 // TODO: just return if !unloading_occurred.
1864 if (unloading_occurred) {
1865 {
1866 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
1867 // Check if there's work to do in the SymbolTable
1868 SymbolTable::do_check_concurrent_work();
1869 }
1870
1871 {
1872 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1873 constraints()->purge_loader_constraints();
1874 resolution_errors()->purge_resolution_errors();
1875 }
1876 }
1877
1878 {
1879 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1880 // Oops referenced by the protection domain cache table may get unreachable independently
1881 // of the class loader (eg. cached protection domain oops). So we need to
1882 // explicitly unlink them here.
1883 _pd_cache_table->unlink();
1884 }
1885
1886 if (do_cleaning) {
1887 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1888 ResolvedMethodTable::trigger_cleanup();
1889 }
1890
1891 return unloading_occurred;
1892 }
1893
1894 void SystemDictionary::oops_do(OopClosure* f) {
1895 f->do_oop(&_java_system_loader);
1896 f->do_oop(&_java_platform_loader);
1897 f->do_oop(&_system_loader_lock_obj);
1898 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1899
1900 // Visit extra methods
1901 invoke_method_table()->oops_do(f);
1902 }
1903
1904 // CDS: scan and relocate all classes in the system dictionary.
1905 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1906 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1907 }
1908
1909 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1910 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1911 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1912 it->push(well_known_klass_addr((WKID)id));
1913 }
1914 }
1915
1916 void SystemDictionary::methods_do(void f(Method*)) {
1917 // Walk methods in loaded classes
1918 ClassLoaderDataGraph::methods_do(f);
1919 // Walk method handle intrinsics
1920 invoke_method_table()->methods_do(f);
1921 }
1922
1923 class RemoveClassesClosure : public CLDClosure {
1924 public:
1925 void do_cld(ClassLoaderData* cld) {
1926 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1927 cld->dictionary()->remove_classes_in_error_state();
1928 }
1929 }
1930 };
1931
1932 void SystemDictionary::remove_classes_in_error_state() {
1933 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1934 RemoveClassesClosure rcc;
1935 ClassLoaderDataGraph::cld_do(&rcc);
1936 }
1937
1938 // ----------------------------------------------------------------------------
1939 // Initialization
1940
1941 void SystemDictionary::initialize(TRAPS) {
1942 // Allocate arrays
1943 _placeholders = new PlaceholderTable(_placeholder_table_size);
1944 _number_of_modifications = 0;
1945 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1946 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1947 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1948 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1949
1950 // Allocate private object used as system class loader lock
1951 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1952 // Initialize basic classes
1953 resolve_preloaded_classes(CHECK);
1954 }
1955
1956 // Compact table of directions on the initialization of klasses:
1957 static const short wk_init_info[] = {
1958 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1959 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1960 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1961 | (int)SystemDictionary::option ),
1962 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1963 #undef WK_KLASS_INIT_INFO
1964 0
1965 };
1966
1967 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) {
1968 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1969 int info = wk_init_info[id - FIRST_WKID];
1970 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1971 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1972 InstanceKlass** klassp = &_well_known_klasses[id];
1973
1974 bool must_load;
1975 #if INCLUDE_JVMCI
1976 if (EnableJVMCI) {
1977 // If JVMCI is enabled we require its classes to be found.
1978 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1979 } else
1980 #endif
1981 {
1982 must_load = (init_opt < SystemDictionary::Opt);
1983 }
1984
1985 if ((*klassp) == NULL) {
1986 Klass* k;
1987 if (must_load) {
1988 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
1989 } else {
1990 k = resolve_or_null(symbol, CHECK_0); // load optional klass
1991 }
1992 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
1993 }
1994 return ((*klassp) != NULL);
1995 }
1996
1997 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1998 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1999 for (int id = (int)start_id; id < (int)limit_id; id++) {
2000 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2001 int info = wk_init_info[id - FIRST_WKID];
2002 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2003 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2004
2005 resolve_wk_klass((WKID)id, opt, CHECK);
2006 }
2007
2008 // move the starting value forward to the limit:
2009 start_id = limit_id;
2010 }
2011
2012 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
2013 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2014
2015 // Create the ModuleEntry for java.base. This call needs to be done here,
2016 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2017 ClassLoader::classLoader_init2(CHECK);
2018
2019 // Preload commonly used klasses
2020 WKID scan = FIRST_WKID;
2021 // first do Object, then String, Class
2022 #if INCLUDE_CDS
2023 if (UseSharedSpaces) {
2024 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2025 // Initialize the constant pool for the Object_class
2026 Object_klass()->constants()->restore_unshareable_info(CHECK);
2027 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2028 } else
2029 #endif
2030 {
2031 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2032 }
2033
2034 // Calculate offsets for String and Class classes since they are loaded and
2035 // can be used after this point.
2036 java_lang_String::compute_offsets();
2037 java_lang_Class::compute_offsets();
2038
2039 // Fixup mirrors for classes loaded before java.lang.Class.
2040 // These calls iterate over the objects currently in the perm gen
2041 // so calling them at this point is matters (not before when there
2042 // are fewer objects and not later after there are more objects
2043 // in the perm gen.
2044 Universe::initialize_basic_type_mirrors(CHECK);
2045 Universe::fixup_mirrors(CHECK);
2046
2047 // do a bunch more:
2048 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2049
2050 // Preload ref klasses and set reference types
2051 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2052 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2053
2054 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2055 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2056 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2057 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2058 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2059
2060 // JSR 292 classes
2061 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2062 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2063 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2064 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2065 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2066
2067 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2068 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2069 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2070 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2071 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2072 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2073 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2074 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2075 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2076 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2077
2078 { // Compute whether we should use checkPackageAccess or NOT
2079 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2080 _has_checkPackageAccess = (method != NULL);
2081 }
2082 }
2083
2084 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2085 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2086 BasicType SystemDictionary::box_klass_type(Klass* k) {
2087 assert(k != NULL, "");
2088 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2089 if (_box_klasses[i] == k)
2090 return (BasicType)i;
2091 }
2092 return T_OBJECT;
2093 }
2094
2095 // Constraints on class loaders. The details of the algorithm can be
2096 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2097 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2098 // that the dictionary needs to maintain a set of contraints that
2099 // must be satisfied by all classes in the dictionary.
2100 // if defining is true, then LinkageError if already in dictionary
2101 // if initiating loader, then ok if InstanceKlass matches existing entry
2102
2103 void SystemDictionary::check_constraints(unsigned int d_hash,
2104 InstanceKlass* k,
2105 Handle class_loader,
2106 bool defining,
2107 TRAPS) {
2108 ResourceMark rm(THREAD);
2109 stringStream ss;
2110 bool throwException = false;
2111
2112 {
2113 Symbol *name = k->name();
2114 ClassLoaderData *loader_data = class_loader_data(class_loader);
2115
2116 MutexLocker mu(SystemDictionary_lock, THREAD);
2117
2118 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2119 if (check != NULL) {
2120 // If different InstanceKlass - duplicate class definition,
2121 // else - ok, class loaded by a different thread in parallel.
2122 // We should only have found it if it was done loading and ok to use.
2123 // The dictionary only holds instance classes, placeholders
2124 // also hold array classes.
2125
2126 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2127 if ((defining == true) || (k != check)) {
2128 throwException = true;
2129 ss.print("loader %s", loader_data->loader_name_and_id());
2130 ss.print(" attempted duplicate %s definition for %s. (%s)",
2131 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2132 } else {
2133 return;
2134 }
2135 }
2136
2137 #ifdef ASSERT
2138 Symbol* ph_check = find_placeholder(name, loader_data);
2139 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2140 #endif
2141
2142 if (throwException == false) {
2143 if (constraints()->check_or_update(k, class_loader, name) == false) {
2144 throwException = true;
2145 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2146 ss.print(" wants to load %s %s.",
2147 k->external_kind(), k->external_name());
2148 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2149 if (existing_klass->class_loader() != class_loader()) {
2150 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2151 existing_klass->external_kind(),
2152 existing_klass->class_loader_data()->loader_name_and_id(),
2153 existing_klass->class_in_module_of_loader(false, true));
2154 } else {
2155 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2156 }
2157 }
2158 }
2159 }
2160
2161 // Throw error now if needed (cannot throw while holding
2162 // SystemDictionary_lock because of rank ordering)
2163 if (throwException == true) {
2164 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2165 }
2166 }
2167
2168 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2169 // have been called.
2170 void SystemDictionary::update_dictionary(unsigned int d_hash,
2171 int p_index, unsigned int p_hash,
2172 InstanceKlass* k,
2173 Handle class_loader,
2174 TRAPS) {
2175 // Compile_lock prevents systemDictionary updates during compilations
2176 assert_locked_or_safepoint(Compile_lock);
2177 Symbol* name = k->name();
2178 ClassLoaderData *loader_data = class_loader_data(class_loader);
2179
2180 {
2181 MutexLocker mu1(SystemDictionary_lock, THREAD);
2182
2183 // See whether biased locking is enabled and if so set it for this
2184 // klass.
2185 // Note that this must be done past the last potential blocking
2186 // point / safepoint. We enable biased locking lazily using a
2187 // VM_Operation to iterate the SystemDictionary and installing the
2188 // biasable mark word into each InstanceKlass's prototype header.
2189 // To avoid race conditions where we accidentally miss enabling the
2190 // optimization for one class in the process of being added to the
2191 // dictionary, we must not safepoint after the test of
2192 // BiasedLocking::enabled().
2193 if (UseBiasedLocking && BiasedLocking::enabled()) {
2194 // Set biased locking bit for all loaded classes; it will be
2195 // cleared if revocation occurs too often for this type
2196 // NOTE that we must only do this when the class is initally
2197 // defined, not each time it is referenced from a new class loader
2198 if (oopDesc::equals(k->class_loader(), class_loader())) {
2199 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2200 }
2201 }
2202
2203 // Make a new dictionary entry.
2204 Dictionary* dictionary = loader_data->dictionary();
2205 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2206 if (sd_check == NULL) {
2207 dictionary->add_klass(d_hash, name, k);
2208 notice_modification();
2209 }
2210 #ifdef ASSERT
2211 sd_check = find_class(d_hash, name, dictionary);
2212 assert (sd_check != NULL, "should have entry in dictionary");
2213 // Note: there may be a placeholder entry: for circularity testing
2214 // or for parallel defines
2215 #endif
2216 SystemDictionary_lock->notify_all();
2217 }
2218 }
2219
2220
2221 // Try to find a class name using the loader constraints. The
2222 // loader constraints might know about a class that isn't fully loaded
2223 // yet and these will be ignored.
2224 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2225 Symbol* class_name, Handle class_loader, TRAPS) {
2226
2227 // First see if it has been loaded directly.
2228 // Force the protection domain to be null. (This removes protection checks.)
2229 Handle no_protection_domain;
2230 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2231 no_protection_domain, CHECK_NULL);
2232 if (klass != NULL)
2233 return klass;
2234
2235 // Now look to see if it has been loaded elsewhere, and is subject to
2236 // a loader constraint that would require this loader to return the
2237 // klass that is already loaded.
2238 if (FieldType::is_array(class_name)) {
2239 // For array classes, their Klass*s are not kept in the
2240 // constraint table. The element Klass*s are.
2241 FieldArrayInfo fd;
2242 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2243 if (t != T_OBJECT) {
2244 klass = Universe::typeArrayKlassObj(t);
2245 } else {
2246 MutexLocker mu(SystemDictionary_lock, THREAD);
2247 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2248 }
2249 // If element class already loaded, allocate array klass
2250 if (klass != NULL) {
2251 klass = klass->array_klass_or_null(fd.dimension());
2252 }
2253 } else {
2254 MutexLocker mu(SystemDictionary_lock, THREAD);
2255 // Non-array classes are easy: simply check the constraint table.
2256 klass = constraints()->find_constrained_klass(class_name, class_loader);
2257 }
2258
2259 return klass;
2260 }
2261
2262
2263 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2264 Handle class_loader1,
2265 Handle class_loader2,
2266 Thread* THREAD) {
2267 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2268 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2269
2270 Symbol* constraint_name = NULL;
2271 // Needs to be in same scope as constraint_name in case a Symbol is created and
2272 // assigned to constraint_name.
2273 FieldArrayInfo fd;
2274 if (!FieldType::is_array(class_name)) {
2275 constraint_name = class_name;
2276 } else {
2277 // For array classes, their Klass*s are not kept in the
2278 // constraint table. The element classes are.
2279 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2280 // primitive types always pass
2281 if (t != T_OBJECT) {
2282 return true;
2283 } else {
2284 constraint_name = fd.object_key();
2285 }
2286 }
2287
2288 Dictionary* dictionary1 = loader_data1->dictionary();
2289 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2290
2291 Dictionary* dictionary2 = loader_data2->dictionary();
2292 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2293
2294 {
2295 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2296 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2297 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2298 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2299 klass2, class_loader2);
2300 }
2301 }
2302
2303 // Add entry to resolution error table to record the error when the first
2304 // attempt to resolve a reference to a class has failed.
2305 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2306 Symbol* error, Symbol* message) {
2307 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2308 int index = resolution_errors()->hash_to_index(hash);
2309 {
2310 MutexLocker ml(SystemDictionary_lock, Thread::current());
2311 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2312 }
2313 }
2314
2315 // Delete a resolution error for RedefineClasses for a constant pool is going away
2316 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2317 resolution_errors()->delete_entry(pool);
2318 }
2319
2320 // Lookup resolution error table. Returns error if found, otherwise NULL.
2321 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2322 Symbol** message) {
2323 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2324 int index = resolution_errors()->hash_to_index(hash);
2325 {
2326 MutexLocker ml(SystemDictionary_lock, Thread::current());
2327 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2328 if (entry != NULL) {
2329 *message = entry->message();
2330 return entry->error();
2331 } else {
2332 return NULL;
2333 }
2334 }
2335 }
2336
2337
2338 // Signature constraints ensure that callers and callees agree about
2339 // the meaning of type names in their signatures. This routine is the
2340 // intake for constraints. It collects them from several places:
2341 //
2342 // * LinkResolver::resolve_method (if check_access is true) requires
2343 // that the resolving class (the caller) and the defining class of
2344 // the resolved method (the callee) agree on each type in the
2345 // method's signature.
2346 //
2347 // * LinkResolver::resolve_interface_method performs exactly the same
2348 // checks.
2349 //
2350 // * LinkResolver::resolve_field requires that the constant pool
2351 // attempting to link to a field agree with the field's defining
2352 // class about the type of the field signature.
2353 //
2354 // * klassVtable::initialize_vtable requires that, when a class
2355 // overrides a vtable entry allocated by a superclass, that the
2356 // overriding method (i.e., the callee) agree with the superclass
2357 // on each type in the method's signature.
2358 //
2359 // * klassItable::initialize_itable requires that, when a class fills
2360 // in its itables, for each non-abstract method installed in an
2361 // itable, the method (i.e., the callee) agree with the interface
2362 // on each type in the method's signature.
2363 //
2364 // All those methods have a boolean (check_access, checkconstraints)
2365 // which turns off the checks. This is used from specialized contexts
2366 // such as bootstrapping, dumping, and debugging.
2367 //
2368 // No direct constraint is placed between the class and its
2369 // supertypes. Constraints are only placed along linked relations
2370 // between callers and callees. When a method overrides or implements
2371 // an abstract method in a supertype (superclass or interface), the
2372 // constraints are placed as if the supertype were the caller to the
2373 // overriding method. (This works well, since callers to the
2374 // supertype have already established agreement between themselves and
2375 // the supertype.) As a result of all this, a class can disagree with
2376 // its supertype about the meaning of a type name, as long as that
2377 // class neither calls a relevant method of the supertype, nor is
2378 // called (perhaps via an override) from the supertype.
2379 //
2380 //
2381 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2382 //
2383 // Make sure all class components (including arrays) in the given
2384 // signature will be resolved to the same class in both loaders.
2385 // Returns the name of the type that failed a loader constraint check, or
2386 // NULL if no constraint failed. No exception except OOME is thrown.
2387 // Arrays are not added to the loader constraint table, their elements are.
2388 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2389 Handle loader1, Handle loader2,
2390 bool is_method, TRAPS) {
2391 // Nothing to do if loaders are the same.
2392 if (oopDesc::equals(loader1(), loader2())) {
2393 return NULL;
2394 }
2395
2396 SignatureStream sig_strm(signature, is_method);
2397 while (!sig_strm.is_done()) {
2398 if (sig_strm.is_object()) {
2399 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2400 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2401 return sig;
2402 }
2403 }
2404 sig_strm.next();
2405 }
2406 return NULL;
2407 }
2408
2409
2410 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2411 Symbol* signature,
2412 TRAPS) {
2413 methodHandle empty;
2414 assert(MethodHandles::is_signature_polymorphic(iid) &&
2415 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2416 iid != vmIntrinsics::_invokeGeneric,
2417 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2418
2419 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2420 int index = invoke_method_table()->hash_to_index(hash);
2421 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2422 methodHandle m;
2423 if (spe == NULL || spe->method() == NULL) {
2424 spe = NULL;
2425 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2426 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2427 if (!Arguments::is_interpreter_only()) {
2428 // Generate a compiled form of the MH intrinsic.
2429 AdapterHandlerLibrary::create_native_wrapper(m);
2430 // Check if have the compiled code.
2431 if (!m->has_compiled_code()) {
2432 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2433 "Out of space in CodeCache for method handle intrinsic", empty);
2434 }
2435 }
2436 // Now grab the lock. We might have to throw away the new method,
2437 // if a racing thread has managed to install one at the same time.
2438 {
2439 MutexLocker ml(SystemDictionary_lock, THREAD);
2440 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2441 if (spe == NULL)
2442 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2443 if (spe->method() == NULL)
2444 spe->set_method(m());
2445 }
2446 }
2447
2448 assert(spe != NULL && spe->method() != NULL, "");
2449 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2450 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2451 "MH intrinsic invariant");
2452 return spe->method();
2453 }
2454
2455 // Helper for unpacking the return value from linkMethod and linkCallSite.
2456 static methodHandle unpack_method_and_appendix(Handle mname,
2457 Klass* accessing_klass,
2458 objArrayHandle appendix_box,
2459 Handle* appendix_result,
2460 TRAPS) {
2461 methodHandle empty;
2462 if (mname.not_null()) {
2463 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2464 if (m != NULL) {
2465 oop appendix = appendix_box->obj_at(0);
2466 if (TraceMethodHandles) {
2467 #ifndef PRODUCT
2468 ttyLocker ttyl;
2469 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2470 m->print();
2471 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2472 tty->cr();
2473 #endif //PRODUCT
2474 }
2475 (*appendix_result) = Handle(THREAD, appendix);
2476 // the target is stored in the cpCache and if a reference to this
2477 // MemberName is dropped we need a way to make sure the
2478 // class_loader containing this method is kept alive.
2479 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2480 this_key->record_dependency(m->method_holder());
2481 return methodHandle(THREAD, m);
2482 }
2483 }
2484 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2485 return empty;
2486 }
2487
2488 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2489 Symbol* name,
2490 Symbol* signature,
2491 Klass* accessing_klass,
2492 Handle *appendix_result,
2493 Handle *method_type_result,
2494 TRAPS) {
2495 methodHandle empty;
2496 assert(THREAD->can_call_java() ,"");
2497 Handle method_type =
2498 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2499
2500 int ref_kind = JVM_REF_invokeVirtual;
2501 oop name_oop = StringTable::intern(name, CHECK_(empty));
2502 Handle name_str (THREAD, name_oop);
2503 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2504 assert(appendix_box->obj_at(0) == NULL, "");
2505
2506 // This should not happen. JDK code should take care of that.
2507 if (accessing_klass == NULL || method_type.is_null()) {
2508 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2509 }
2510
2511 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2512 JavaCallArguments args;
2513 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2514 args.push_int(ref_kind);
2515 args.push_oop(Handle(THREAD, klass->java_mirror()));
2516 args.push_oop(name_str);
2517 args.push_oop(method_type);
2518 args.push_oop(appendix_box);
2519 JavaValue result(T_OBJECT);
2520 JavaCalls::call_static(&result,
2521 SystemDictionary::MethodHandleNatives_klass(),
2522 vmSymbols::linkMethod_name(),
2523 vmSymbols::linkMethod_signature(),
2524 &args, CHECK_(empty));
2525 Handle mname(THREAD, (oop) result.get_jobject());
2526 (*method_type_result) = method_type;
2527 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2528 }
2529
2530 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2531 // We must ensure that all class loaders everywhere will reach this class, for any client.
2532 // This is a safe bet for public classes in java.lang, such as Object and String.
2533 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2534 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2535 static bool is_always_visible_class(oop mirror) {
2536 Klass* klass = java_lang_Class::as_Klass(mirror);
2537 if (klass->is_objArray_klass()) {
2538 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2539 }
2540 if (klass->is_typeArray_klass()) {
2541 return true; // primitive array
2542 }
2543 assert(klass->is_instance_klass(), "%s", klass->external_name());
2544 return klass->is_public() &&
2545 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2546 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2547 }
2548
2549
2550 // Return the Java mirror (java.lang.Class instance) for a single-character
2551 // descriptor. This result, when available, is the same as produced by the
2552 // heavier API point of the same name that takes a Symbol.
2553 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2554 return java_lang_Class::primitive_mirror(char2type(signature_char));
2555 }
2556
2557 // Find or construct the Java mirror (java.lang.Class instance) for a
2558 // for the given field type signature, as interpreted relative to the
2559 // given class loader. Handles primitives, void, references, arrays,
2560 // and all other reflectable types, except method types.
2561 // N.B. Code in reflection should use this entry point.
2562 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2563 Klass* accessing_klass,
2564 Handle class_loader,
2565 Handle protection_domain,
2566 SignatureStream::FailureMode failure_mode,
2567 TRAPS) {
2568 Handle empty;
2569
2570 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2571 "one or the other, or perhaps neither");
2572
2573 Symbol* type = signature;
2574
2575 // What we have here must be a valid field descriptor,
2576 // and all valid field descriptors are supported.
2577 // Produce the same java.lang.Class that reflection reports.
2578 if (type->utf8_length() == 1) {
2579
2580 // It's a primitive. (Void has a primitive mirror too.)
2581 char ch = (char) type->byte_at(0);
2582 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2583 return Handle(THREAD, find_java_mirror_for_type(ch));
2584
2585 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2586
2587 // It's a reference type.
2588 if (accessing_klass != NULL) {
2589 class_loader = Handle(THREAD, accessing_klass->class_loader());
2590 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2591 }
2592 Klass* constant_type_klass;
2593 if (failure_mode == SignatureStream::ReturnNull) {
2594 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2595 CHECK_(empty));
2596 } else {
2597 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2598 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2599 throw_error, CHECK_(empty));
2600 }
2601 if (constant_type_klass == NULL) {
2602 return Handle(); // report failure this way
2603 }
2604 Handle mirror(THREAD, constant_type_klass->java_mirror());
2605
2606 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2607 if (accessing_klass != NULL) {
2608 Klass* sel_klass = constant_type_klass;
2609 bool fold_type_to_class = true;
2610 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2611 fold_type_to_class, CHECK_(empty));
2612 }
2613
2614 return mirror;
2615
2616 }
2617
2618 // Fall through to an error.
2619 assert(false, "unsupported mirror syntax");
2620 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2621 }
2622
2623
2624 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2625 // signature, as interpreted relative to the given class loader.
2626 // Because of class loader constraints, all method handle usage must be
2627 // consistent with this loader.
2628 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2629 Klass* accessing_klass,
2630 TRAPS) {
2631 Handle empty;
2632 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2633 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2634 int index = invoke_method_table()->hash_to_index(hash);
2635 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2636 if (spe != NULL && spe->method_type() != NULL) {
2637 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2638 return Handle(THREAD, spe->method_type());
2639 } else if (!THREAD->can_call_java()) {
2640 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2641 return Handle(); // do not attempt from within compiler, unless it was cached
2642 }
2643
2644 Handle class_loader, protection_domain;
2645 if (accessing_klass != NULL) {
2646 class_loader = Handle(THREAD, accessing_klass->class_loader());
2647 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2648 }
2649 bool can_be_cached = true;
2650 int npts = ArgumentCount(signature).size();
2651 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2652 int arg = 0;
2653 Handle rt; // the return type from the signature
2654 ResourceMark rm(THREAD);
2655 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2656 oop mirror = NULL;
2657 if (can_be_cached) {
2658 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2659 mirror = ss.as_java_mirror(Handle(), Handle(),
2660 SignatureStream::ReturnNull, CHECK_(empty));
2661 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2662 // Fall back to accessing_klass context.
2663 can_be_cached = false;
2664 }
2665 }
2666 if (!can_be_cached) {
2667 // Resolve, throwing a real error if it doesn't work.
2668 mirror = ss.as_java_mirror(class_loader, protection_domain,
2669 SignatureStream::NCDFError, CHECK_(empty));
2670 }
2671 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2672 if (ss.at_return_type())
2673 rt = Handle(THREAD, mirror);
2674 else
2675 pts->obj_at_put(arg++, mirror);
2676
2677 // Check accessibility.
2678 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2679 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2680 mirror = NULL; // safety
2681 // Emulate ConstantPool::verify_constant_pool_resolve.
2682 bool fold_type_to_class = true;
2683 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2684 fold_type_to_class, CHECK_(empty));
2685 }
2686 }
2687 assert(arg == npts, "");
2688
2689 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2690 JavaCallArguments args(Handle(THREAD, rt()));
2691 args.push_oop(pts);
2692 JavaValue result(T_OBJECT);
2693 JavaCalls::call_static(&result,
2694 SystemDictionary::MethodHandleNatives_klass(),
2695 vmSymbols::findMethodHandleType_name(),
2696 vmSymbols::findMethodHandleType_signature(),
2697 &args, CHECK_(empty));
2698 Handle method_type(THREAD, (oop) result.get_jobject());
2699
2700 if (can_be_cached) {
2701 // We can cache this MethodType inside the JVM.
2702 MutexLocker ml(SystemDictionary_lock, THREAD);
2703 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2704 if (spe == NULL)
2705 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2706 if (spe->method_type() == NULL) {
2707 spe->set_method_type(method_type());
2708 }
2709 }
2710
2711 // report back to the caller with the MethodType
2712 return method_type;
2713 }
2714
2715 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2716 Klass* accessing_klass,
2717 TRAPS) {
2718 Handle empty;
2719 ResourceMark rm(THREAD);
2720 SignatureStream ss(signature, /*is_method=*/ false);
2721 if (!ss.is_done()) {
2722 Handle class_loader, protection_domain;
2723 if (accessing_klass != NULL) {
2724 class_loader = Handle(THREAD, accessing_klass->class_loader());
2725 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2726 }
2727 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2728 ss.next();
2729 if (ss.is_done()) {
2730 return Handle(THREAD, mirror);
2731 }
2732 }
2733 return empty;
2734 }
2735
2736 // Ask Java code to find or construct a method handle constant.
2737 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2738 int ref_kind, //e.g., JVM_REF_invokeVirtual
2739 Klass* callee,
2740 Symbol* name,
2741 Symbol* signature,
2742 TRAPS) {
2743 Handle empty;
2744 if (caller == NULL) {
2745 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2746 }
2747 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2748 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2749
2750 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2751 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2752 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2753 java_lang_invoke_MemberName::set_name (mname(), name_str());
2754 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2755 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2756
2757 if (ref_kind == JVM_REF_invokeVirtual &&
2758 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2759 // Skip resolution for public signature polymorphic methods such as
2760 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2761 // They require appendix argument which MemberName resolution doesn't handle.
2762 // There's special logic on JDK side to handle them
2763 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2764 } else {
2765 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2766 }
2767
2768 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2769 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2770
2771 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2772 JavaCallArguments args;
2773 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2774 args.push_int(ref_kind);
2775 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2776 args.push_oop(name_str);
2777 args.push_oop(type);
2778 JavaValue result(T_OBJECT);
2779 JavaCalls::call_static(&result,
2780 SystemDictionary::MethodHandleNatives_klass(),
2781 vmSymbols::linkMethodHandleConstant_name(),
2782 vmSymbols::linkMethodHandleConstant_signature(),
2783 &args, CHECK_(empty));
2784 return Handle(THREAD, (oop) result.get_jobject());
2785 }
2786
2787 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2788 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2789 int condy_index,
2790 Handle bootstrap_specifier,
2791 Symbol* name,
2792 Symbol* type,
2793 TRAPS) {
2794 Handle empty;
2795 Handle bsm, info;
2796 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2797 bsm = bootstrap_specifier;
2798 } else {
2799 assert(bootstrap_specifier->is_objArray(), "");
2800 objArrayOop args = (objArrayOop) bootstrap_specifier();
2801 assert(args->length() == 2, "");
2802 bsm = Handle(THREAD, args->obj_at(0));
2803 info = Handle(THREAD, args->obj_at(1));
2804 }
2805 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2806 "caller must supply a valid BSM");
2807
2808 // This should not happen. JDK code should take care of that.
2809 if (caller == NULL) {
2810 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2811 }
2812
2813 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2814
2815 // Resolve the constant type in the context of the caller class
2816 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2817 CHECK_(empty));
2818
2819 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2820 JavaCallArguments args;
2821 args.push_oop(Handle(THREAD, caller->java_mirror()));
2822 args.push_int(condy_index);
2823 args.push_oop(bsm);
2824 args.push_oop(constant_name);
2825 args.push_oop(type_mirror);
2826 args.push_oop(info);
2827 JavaValue result(T_OBJECT);
2828 JavaCalls::call_static(&result,
2829 SystemDictionary::MethodHandleNatives_klass(),
2830 vmSymbols::linkDynamicConstant_name(),
2831 vmSymbols::linkDynamicConstant_signature(),
2832 &args, CHECK_(empty));
2833
2834 return Handle(THREAD, (oop) result.get_jobject());
2835 }
2836
2837 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2838 // name and signature, as interpreted relative to the given class loader.
2839 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2840 int indy_index,
2841 Handle bootstrap_specifier,
2842 Symbol* name,
2843 Symbol* type,
2844 Handle *appendix_result,
2845 Handle *method_type_result,
2846 TRAPS) {
2847 methodHandle empty;
2848 Handle bsm, info;
2849 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2850 bsm = bootstrap_specifier;
2851 } else {
2852 objArrayOop args = (objArrayOop) bootstrap_specifier();
2853 assert(args->length() == 2, "");
2854 bsm = Handle(THREAD, args->obj_at(0));
2855 info = Handle(THREAD, args->obj_at(1));
2856 }
2857 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2858 "caller must supply a valid BSM");
2859
2860 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2861 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2862
2863 // This should not happen. JDK code should take care of that.
2864 if (caller == NULL || method_type.is_null()) {
2865 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2866 }
2867
2868 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2869 assert(appendix_box->obj_at(0) == NULL, "");
2870
2871 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2872 JavaCallArguments args;
2873 args.push_oop(Handle(THREAD, caller->java_mirror()));
2874 args.push_int(indy_index);
2875 args.push_oop(bsm);
2876 args.push_oop(method_name);
2877 args.push_oop(method_type);
2878 args.push_oop(info);
2879 args.push_oop(appendix_box);
2880 JavaValue result(T_OBJECT);
2881 JavaCalls::call_static(&result,
2882 SystemDictionary::MethodHandleNatives_klass(),
2883 vmSymbols::linkCallSite_name(),
2884 vmSymbols::linkCallSite_signature(),
2885 &args, CHECK_(empty));
2886 Handle mname(THREAD, (oop) result.get_jobject());
2887 (*method_type_result) = method_type;
2888 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2889 }
2890
2891 // Protection domain cache table handling
2892
2893 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2894 return _pd_cache_table->get(protection_domain);
2895 }
2896
2897 #if INCLUDE_CDS
2898 void SystemDictionary::reorder_dictionary_for_sharing() {
2899 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2900 }
2901 #endif
2902
2903 size_t SystemDictionary::count_bytes_for_buckets() {
2904 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2905 }
2906
2907 size_t SystemDictionary::count_bytes_for_table() {
2908 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2909 }
2910
2911 void SystemDictionary::copy_buckets(char* top, char* end) {
2912 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2913 }
2914
2915 void SystemDictionary::copy_table(char* top, char* end) {
2916 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2917 }
2918
2919 // ----------------------------------------------------------------------------
2920 void SystemDictionary::print_shared(outputStream *st) {
2921 shared_dictionary()->print_on(st);
2922 }
2923
2924 void SystemDictionary::print_on(outputStream *st) {
2925 if (shared_dictionary() != NULL) {
2926 st->print_cr("Shared Dictionary");
2927 shared_dictionary()->print_on(st);
2928 st->cr();
2929 }
2930
2931 GCMutexLocker mu(SystemDictionary_lock);
2932
2933 ClassLoaderDataGraph::print_dictionary(st);
2934
2935 // Placeholders
2936 placeholders()->print_on(st);
2937 st->cr();
2938
2939 // loader constraints - print under SD_lock
2940 constraints()->print_on(st);
2941 st->cr();
2942
2943 _pd_cache_table->print_on(st);
2944 st->cr();
2945 }
2946
2947 void SystemDictionary::verify() {
2948 guarantee(constraints() != NULL,
2949 "Verify of loader constraints failed");
2950 guarantee(placeholders()->number_of_entries() >= 0,
2951 "Verify of placeholders failed");
2952
2953 GCMutexLocker mu(SystemDictionary_lock);
2954
2955 // Verify dictionary
2956 ClassLoaderDataGraph::verify_dictionary();
2957
2958 placeholders()->verify();
2959
2960 // Verify constraint table
2961 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2962 constraints()->verify(placeholders());
2963
2964 _pd_cache_table->verify();
2965 }
2966
2967 void SystemDictionary::dump(outputStream *st, bool verbose) {
2968 assert_locked_or_safepoint(SystemDictionary_lock);
2969 if (verbose) {
2970 print_on(st);
2971 } else {
2972 if (shared_dictionary() != NULL) {
2973 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2974 }
2975 ClassLoaderDataGraph::print_dictionary_statistics(st);
2976 placeholders()->print_table_statistics(st, "Placeholder Table");
2977 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2978 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2979 }
2980 }
2981
2982 // Utility for dumping dictionaries.
2983 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2984 DCmdWithParser(output, heap),
2985 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2986 "BOOLEAN", false, "false") {
2987 _dcmdparser.add_dcmd_option(&_verbose);
2988 }
2989
2990 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2991 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2992 _verbose.value());
2993 VMThread::execute(&dumper);
2994 }
2995
2996 int SystemDictionaryDCmd::num_arguments() {
2997 ResourceMark rm;
2998 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2999 if (dcmd != NULL) {
3000 DCmdMark mark(dcmd);
3001 return dcmd->_dcmdparser.num_arguments();
3002 } else {
3003 return 0;
3004 }
3005 }
3006
3007 class CombineDictionariesClosure : public CLDClosure {
3008 private:
3009 Dictionary* _master_dictionary;
3010 public:
3011 CombineDictionariesClosure(Dictionary* master_dictionary) :
3012 _master_dictionary(master_dictionary) {}
3013 void do_cld(ClassLoaderData* cld) {
3014 ResourceMark rm;
3015 if (cld->is_unsafe_anonymous()) {
3016 return;
3017 }
3018 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3019 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3020 Dictionary* curr_dictionary = cld->dictionary();
3021 DictionaryEntry* p = curr_dictionary->bucket(i);
3022 while (p != NULL) {
3023 Symbol* name = p->instance_klass()->name();
3024 unsigned int d_hash = _master_dictionary->compute_hash(name);
3025 int d_index = _master_dictionary->hash_to_index(d_hash);
3026 DictionaryEntry* next = p->next();
3027 if (p->literal()->class_loader_data() != cld) {
3028 // This is an initiating class loader entry; don't use it
3029 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3030 curr_dictionary->free_entry(p);
3031 } else {
3032 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3033 curr_dictionary->unlink_entry(p);
3034 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3035 _master_dictionary->add_entry(d_index, p);
3036 }
3037 p = next;
3038 }
3039 *curr_dictionary->bucket_addr(i) = NULL;
3040 }
3041 }
3042 }
3043 };
3044
3045 // Combining platform and system loader dictionaries into boot loader dictionary.
3046 // During run time, we only have one shared dictionary.
3047 void SystemDictionary::combine_shared_dictionaries() {
3048 assert(DumpSharedSpaces, "dump time only");
3049 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3050 CombineDictionariesClosure cdc(master_dictionary);
3051 ClassLoaderDataGraph::cld_do(&cdc);
3052
3053 // These tables are no longer valid or necessary. Keeping them around will
3054 // cause SystemDictionary::verify() to fail. Let's empty them.
3055 _placeholders = new PlaceholderTable(_placeholder_table_size);
3056 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3057
3058 NOT_PRODUCT(SystemDictionary::verify());
3059 }
3060
3061 void SystemDictionary::initialize_oop_storage() {
3062 _vm_weak_oop_storage =
3063 new OopStorage("VM Weak Oop Handles",
3064 VMWeakAlloc_lock,
3065 VMWeakActive_lock);
3066 }
3067
3068 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3069 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3070 return _vm_weak_oop_storage;
3071 }