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/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/systemDictionary.hpp"
44 #include "classfile/vmSymbols.hpp"
45 #include "code/codeCache.hpp"
46 #include "compiler/compileBroker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "gc/shared/oopStorage.inline.hpp"
49 #include "interpreter/bytecodeStream.hpp"
50 #include "interpreter/interpreter.hpp"
51 #include "jfr/jfrEvents.hpp"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/filemap.hpp"
55 #include "memory/heapShared.hpp"
56 #include "memory/metaspaceClosure.hpp"
57 #include "memory/oopFactory.hpp"
58 #include "memory/resourceArea.hpp"
59 #include "oops/access.inline.hpp"
60 #include "oops/instanceKlass.hpp"
61 #include "oops/instanceRefKlass.hpp"
62 #include "oops/klass.inline.hpp"
63 #include "oops/method.inline.hpp"
64 #include "oops/methodData.hpp"
65 #include "oops/objArrayKlass.hpp"
66 #include "oops/objArrayOop.inline.hpp"
67 #include "oops/oop.inline.hpp"
68 #include "oops/symbol.hpp"
69 #include "oops/typeArrayKlass.hpp"
70 #include "prims/jvmtiEnvBase.hpp"
71 #include "prims/resolvedMethodTable.hpp"
72 #include "prims/methodHandles.hpp"
73 #include "runtime/arguments.hpp"
74 #include "runtime/arguments_ext.hpp"
75 #include "runtime/biasedLocking.hpp"
76 #include "runtime/fieldType.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/orderAccess.hpp"
82 #include "runtime/sharedRuntime.hpp"
83 #include "runtime/signature.hpp"
84 #include "services/classLoadingService.hpp"
85 #include "services/diagnosticCommand.hpp"
86 #include "services/threadService.hpp"
87 #include "utilities/macros.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JVMCI
92 #include "jvmci/jvmciRuntime.hpp"
93 #endif
94 #if INCLUDE_JFR
95 #include "jfr/jfr.hpp"
96 #endif
97
98 PlaceholderTable* SystemDictionary::_placeholders = NULL;
99 Dictionary* SystemDictionary::_shared_dictionary = NULL;
100 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
101 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
102 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
103 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
104
105 int SystemDictionary::_number_of_modifications = 0;
106 oop SystemDictionary::_system_loader_lock_obj = NULL;
107
108 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
109 = { NULL /*, NULL...*/ };
110
111 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
112
113 oop SystemDictionary::_java_system_loader = NULL;
114 oop SystemDictionary::_java_platform_loader = NULL;
115
116 bool SystemDictionary::_has_checkPackageAccess = false;
117
118 // Default ProtectionDomainCacheSize value
119
120 const int defaultProtectionDomainCacheSize = 1009;
121
122 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
123
124
125 // ----------------------------------------------------------------------------
126 // Java-level SystemLoader and PlatformLoader
127
128 oop SystemDictionary::java_system_loader() {
129 return _java_system_loader;
130 }
131
132 oop SystemDictionary::java_platform_loader() {
133 return _java_platform_loader;
134 }
135
136 void SystemDictionary::compute_java_loaders(TRAPS) {
137 JavaValue result(T_OBJECT);
138 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
139 JavaCalls::call_static(&result,
140 class_loader_klass,
141 vmSymbols::getSystemClassLoader_name(),
142 vmSymbols::void_classloader_signature(),
143 CHECK);
144
145 _java_system_loader = (oop)result.get_jobject();
146
147 JavaCalls::call_static(&result,
148 class_loader_klass,
149 vmSymbols::getPlatformClassLoader_name(),
150 vmSymbols::void_classloader_signature(),
151 CHECK);
152
153 _java_platform_loader = (oop)result.get_jobject();
154 }
155
156 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
157 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
158 return ClassLoaderDataGraph::find_or_create(class_loader);
159 }
160
161 // ----------------------------------------------------------------------------
162 // Parallel class loading check
163
164 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
165 if (class_loader.is_null()) return true;
166 if (AlwaysLockClassLoader) return false;
167 return java_lang_ClassLoader::parallelCapable(class_loader());
168 }
169 // ----------------------------------------------------------------------------
170 // ParallelDefineClass flag does not apply to bootclass loader
171 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
172 if (class_loader.is_null()) return false;
173 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
174 return true;
175 }
176 return false;
177 }
178
179 // Returns true if the passed class loader is the builtin application class loader
180 // or a custom system class loader. A customer system class loader can be
181 // specified via -Djava.system.class.loader.
182 bool SystemDictionary::is_system_class_loader(oop class_loader) {
183 if (class_loader == NULL) {
184 return false;
185 }
186 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
187 oopDesc::equals(class_loader, _java_system_loader));
188 }
189
190 // Returns true if the passed class loader is the platform class loader.
191 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
192 if (class_loader == NULL) {
193 return false;
194 }
195 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
196 }
197
198 // ----------------------------------------------------------------------------
199 // Resolving of classes
200
201 // Forwards to resolve_or_null
202
203 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
204 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
205 if (HAS_PENDING_EXCEPTION || klass == NULL) {
206 // can return a null klass
207 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
208 }
209 return klass;
210 }
211
212 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
213 bool throw_error,
214 Klass* klass, TRAPS) {
215 if (HAS_PENDING_EXCEPTION) {
216 // If we have a pending exception we forward it to the caller, unless throw_error is true,
217 // in which case we have to check whether the pending exception is a ClassNotFoundException,
218 // and if so convert it to a NoClassDefFoundError
219 // And chain the original ClassNotFoundException
220 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
221 ResourceMark rm(THREAD);
222 assert(klass == NULL, "Should not have result with exception pending");
223 Handle e(THREAD, PENDING_EXCEPTION);
224 CLEAR_PENDING_EXCEPTION;
225 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
226 } else {
227 return NULL;
228 }
229 }
230 // Class not found, throw appropriate error or exception depending on value of throw_error
231 if (klass == NULL) {
232 ResourceMark rm(THREAD);
233 if (throw_error) {
234 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
235 } else {
236 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
237 }
238 }
239 return klass;
240 }
241
242
243 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
244 bool throw_error, TRAPS)
245 {
246 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
247 }
248
249
250 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
251
252 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
253 if (FieldType::is_array(class_name)) {
254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
255 } else {
256 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
257 }
258 }
259
260 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
261 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
262 Handle class_loader,
263 Handle protection_domain,
264 TRAPS) {
265 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
266 if (FieldType::is_obj(class_name)) {
267 ResourceMark rm(THREAD);
268 // Ignore wrapping L and ;.
269 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
270 class_name->utf8_length() - 2, CHECK_NULL);
271 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
272 } else {
273 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
274 }
275 }
276
277 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
278 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
279 }
280
281 // Forwards to resolve_instance_class_or_null
282
283 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
284 Handle class_loader,
285 Handle protection_domain,
286 TRAPS) {
287 assert(FieldType::is_array(class_name), "must be array");
288 Klass* k = NULL;
289 FieldArrayInfo fd;
290 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
291 // of this call
292 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
293 if (t == T_OBJECT) {
294 // naked oop "k" is OK here -- we assign back into it
295 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
296 class_loader,
297 protection_domain,
298 CHECK_NULL);
299 if (k != NULL) {
300 k = k->array_klass(fd.dimension(), CHECK_NULL);
301 }
302 } else {
303 k = Universe::typeArrayKlassObj(t);
304 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
305 }
306 return k;
307 }
308
309
310 // Must be called for any super-class or super-interface resolution
311 // during class definition to allow class circularity checking
312 // super-interface callers:
313 // parse_interfaces - for defineClass & jvmtiRedefineClasses
314 // super-class callers:
315 // ClassFileParser - for defineClass & jvmtiRedefineClasses
316 // load_shared_class - while loading a class from shared archive
317 // resolve_instance_class_or_null:
318 // via: handle_parallel_super_load
319 // when resolving a class that has an existing placeholder with
320 // a saved superclass [i.e. a defineClass is currently in progress]
321 // if another thread is trying to resolve the class, it must do
322 // super-class checks on its own thread to catch class circularity
323 // This last call is critical in class circularity checking for cases
324 // where classloading is delegated to different threads and the
325 // classloader lock is released.
326 // Take the case: Base->Super->Base
327 // 1. If thread T1 tries to do a defineClass of class Base
328 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
329 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
330 // so it tries to load Super
331 // 3. If we load the class internally, or user classloader uses same thread
332 // loadClassFromxxx or defineClass via parseClassFile Super ...
333 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
334 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
335 // 3.4 calls resolve_super_or_fail Base
336 // 3.5 finds T1,Base -> throws class circularity
337 //OR 4. If T2 tries to resolve Super via defineClass Super ...
338 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
339 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
340 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
341 // 4.4 finds T2, Super -> throws class circularity
342 // Must be called, even if superclass is null, since this is
343 // where the placeholder entry is created which claims this
344 // thread is loading this class/classloader.
345 // Be careful when modifying this code: once you have run
346 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
347 // you need to find_and_remove it before returning.
348 // So be careful to not exit with a CHECK_ macro betweeen these calls.
349 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
350 Symbol* super_name,
351 Handle class_loader,
352 Handle protection_domain,
353 bool is_superclass,
354 TRAPS) {
355 assert(!FieldType::is_array(super_name), "invalid super class name");
356 #if INCLUDE_CDS
357 if (DumpSharedSpaces) {
358 // Special processing for CDS dump time.
359 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
360 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
361 if (k) {
362 return k;
363 }
364 }
365 #endif // INCLUDE_CDS
366
367 // Double-check, if child class is already loaded, just return super-class,interface
368 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
369 // dictionary.
370 // Make sure there's a placeholder for the *child* before resolving.
371 // Used as a claim that this thread is currently loading superclass/classloader
372 // Used here for ClassCircularity checks and also for heap verification
373 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
374 // Must check ClassCircularity before checking if super class is already loaded.
375 //
376 // We might not already have a placeholder if this child_name was
377 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
378 // the name of the class might not be known until the stream is actually
379 // parsed.
380 // Bugs 4643874, 4715493
381
382 ClassLoaderData* loader_data = class_loader_data(class_loader);
383 Dictionary* dictionary = loader_data->dictionary();
384 unsigned int d_hash = dictionary->compute_hash(child_name);
385 unsigned int p_hash = placeholders()->compute_hash(child_name);
386 int p_index = placeholders()->hash_to_index(p_hash);
387 // can't throw error holding a lock
388 bool child_already_loaded = false;
389 bool throw_circularity_error = false;
390 {
391 MutexLocker mu(SystemDictionary_lock, THREAD);
392 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
393 InstanceKlass* quicksuperk;
394 // to support // loading: if child done loading, just return superclass
395 // if super_name, & class_loader don't match:
396 // if initial define, SD update will give LinkageError
397 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
398 // so we don't throw an exception here.
399 // see: nsk redefclass014 & java.lang.instrument Instrument032
400 if ((childk != NULL ) && (is_superclass) &&
401 ((quicksuperk = childk->java_super()) != NULL) &&
402 ((quicksuperk->name() == super_name) &&
403 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
404 return quicksuperk;
405 } else {
406 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
407 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
408 throw_circularity_error = true;
409 }
410 }
411 if (!throw_circularity_error) {
412 // Be careful not to exit resolve_super
413 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
414 }
415 }
416 if (throw_circularity_error) {
417 ResourceMark rm(THREAD);
418 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
419 }
420
421 // java.lang.Object should have been found above
422 assert(super_name != NULL, "null super class for resolving");
423 // Resolve the super class or interface, check results on return
424 InstanceKlass* superk =
425 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
426 class_loader,
427 protection_domain,
428 THREAD);
429
430 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
431 // It is no longer necessary to keep the placeholder table alive until update_dictionary
432 // or error. GC used to walk the placeholder table as strong roots.
433 // The instanceKlass is kept alive because the class loader is on the stack,
434 // which keeps the loader_data alive, as well as all instanceKlasses in
435 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
436 {
437 MutexLocker mu(SystemDictionary_lock, THREAD);
438 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
439 SystemDictionary_lock->notify_all();
440 }
441 if (HAS_PENDING_EXCEPTION || superk == NULL) {
442 // can null superk
443 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
444 assert(k == NULL || k == superk, "must be");
445 if (k == NULL) {
446 superk = NULL;
447 }
448 }
449
450 return superk;
451 }
452
453 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
454 Handle class_loader,
455 Handle protection_domain,
456 TRAPS) {
457 if(!has_checkPackageAccess()) return;
458
459 // Now we have to call back to java to check if the initating class has access
460 JavaValue result(T_VOID);
461 LogTarget(Debug, protectiondomain) lt;
462 if (lt.is_enabled()) {
463 ResourceMark rm;
464 // Print out trace information
465 LogStream ls(lt);
466 ls.print_cr("Checking package access");
467 if (class_loader() != NULL) {
468 ls.print("class loader: ");
469 class_loader()->print_value_on(&ls);
470 } else {
471 ls.print_cr("class loader: NULL");
472 }
473 if (protection_domain() != NULL) {
474 ls.print(" protection domain: ");
475 protection_domain()->print_value_on(&ls);
476 } else {
477 ls.print_cr(" protection domain: NULL");
478 }
479 ls.print(" loading: "); klass->print_value_on(&ls);
480 ls.cr();
481 }
482
483 // This handle and the class_loader handle passed in keeps this class from
484 // being unloaded through several GC points.
485 // The class_loader handle passed in is the initiating loader.
486 Handle mirror(THREAD, klass->java_mirror());
487
488 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
489 JavaCalls::call_special(&result,
490 class_loader,
491 system_loader,
492 vmSymbols::checkPackageAccess_name(),
493 vmSymbols::class_protectiondomain_signature(),
494 mirror,
495 protection_domain,
496 THREAD);
497
498 if (HAS_PENDING_EXCEPTION) {
499 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
500 } else {
501 log_debug(protectiondomain)("granted");
502 }
503
504 if (HAS_PENDING_EXCEPTION) return;
505
506 // If no exception has been thrown, we have validated the protection domain
507 // Insert the protection domain of the initiating class into the set.
508 {
509 ClassLoaderData* loader_data = class_loader_data(class_loader);
510 Dictionary* dictionary = loader_data->dictionary();
511
512 Symbol* kn = klass->name();
513 unsigned int d_hash = dictionary->compute_hash(kn);
514
515 MutexLocker mu(SystemDictionary_lock, THREAD);
516 int d_index = dictionary->hash_to_index(d_hash);
517 dictionary->add_protection_domain(d_index, d_hash, klass,
518 protection_domain, THREAD);
519 }
520 }
521
522 // We only get here if this thread finds that another thread
523 // has already claimed the placeholder token for the current operation,
524 // but that other thread either never owned or gave up the
525 // object lock
526 // Waits on SystemDictionary_lock to indicate placeholder table updated
527 // On return, caller must recheck placeholder table state
528 //
529 // We only get here if
530 // 1) custom classLoader, i.e. not bootstrap classloader
531 // 2) custom classLoader has broken the class loader objectLock
532 // so another thread got here in parallel
533 //
534 // lockObject must be held.
535 // Complicated dance due to lock ordering:
536 // Must first release the classloader object lock to
537 // allow initial definer to complete the class definition
538 // and to avoid deadlock
539 // Reclaim classloader lock object with same original recursion count
540 // Must release SystemDictionary_lock after notify, since
541 // class loader lock must be claimed before SystemDictionary_lock
542 // to prevent deadlocks
543 //
544 // The notify allows applications that did an untimed wait() on
545 // the classloader object lock to not hang.
546 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
547 assert_lock_strong(SystemDictionary_lock);
548
549 bool calledholdinglock
550 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
551 assert(calledholdinglock,"must hold lock for notify");
552 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
553 ObjectSynchronizer::notifyall(lockObject, THREAD);
554 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
555 SystemDictionary_lock->wait();
556 SystemDictionary_lock->unlock();
557 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
558 SystemDictionary_lock->lock();
559 }
560
561 // If the class in is in the placeholder table, class loading is in progress
562 // For cases where the application changes threads to load classes, it
563 // is critical to ClassCircularity detection that we try loading
564 // the superclass on the same thread internally, so we do parallel
565 // super class loading here.
566 // This also is critical in cases where the original thread gets stalled
567 // even in non-circularity situations.
568 // Note: must call resolve_super_or_fail even if null super -
569 // to force placeholder entry creation for this class for circularity detection
570 // Caller must check for pending exception
571 // Returns non-null Klass* if other thread has completed load
572 // and we are done,
573 // If return null Klass* and no pending exception, the caller must load the class
574 InstanceKlass* SystemDictionary::handle_parallel_super_load(
575 Symbol* name, Symbol* superclassname, Handle class_loader,
576 Handle protection_domain, Handle lockObject, TRAPS) {
577
578 ClassLoaderData* loader_data = class_loader_data(class_loader);
579 Dictionary* dictionary = loader_data->dictionary();
580 unsigned int d_hash = dictionary->compute_hash(name);
581 unsigned int p_hash = placeholders()->compute_hash(name);
582 int p_index = placeholders()->hash_to_index(p_hash);
583
584 // superk is not used, resolve_super called for circularity check only
585 // This code is reached in two situations. One if this thread
586 // is loading the same class twice (e.g. ClassCircularity, or
587 // java.lang.instrument).
588 // The second is if another thread started the resolve_super first
589 // and has not yet finished.
590 // In both cases the original caller will clean up the placeholder
591 // entry on error.
592 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
593 superclassname,
594 class_loader,
595 protection_domain,
596 true,
597 CHECK_NULL);
598
599 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
600 // Serial class loaders and bootstrap classloader do wait for superclass loads
601 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
602 MutexLocker mu(SystemDictionary_lock, THREAD);
603 // Check if classloading completed while we were loading superclass or waiting
604 return find_class(d_hash, name, dictionary);
605 }
606
607 // must loop to both handle other placeholder updates
608 // and spurious notifications
609 bool super_load_in_progress = true;
610 PlaceholderEntry* placeholder;
611 while (super_load_in_progress) {
612 MutexLocker mu(SystemDictionary_lock, THREAD);
613 // Check if classloading completed while we were loading superclass or waiting
614 InstanceKlass* check = find_class(d_hash, name, dictionary);
615 if (check != NULL) {
616 // Klass is already loaded, so just return it
617 return check;
618 } else {
619 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
620 if (placeholder && placeholder->super_load_in_progress() ){
621 // We only get here if the application has released the
622 // classloader lock when another thread was in the middle of loading a
623 // superclass/superinterface for this class, and now
624 // this thread is also trying to load this class.
625 // To minimize surprises, the first thread that started to
626 // load a class should be the one to complete the loading
627 // with the classfile it initially expected.
628 // This logic has the current thread wait once it has done
629 // all the superclass/superinterface loading it can, until
630 // the original thread completes the class loading or fails
631 // If it completes we will use the resulting InstanceKlass
632 // which we will find below in the systemDictionary.
633 // We also get here for parallel bootstrap classloader
634 if (class_loader.is_null()) {
635 SystemDictionary_lock->wait();
636 } else {
637 double_lock_wait(lockObject, THREAD);
638 }
639 } else {
640 // If not in SD and not in PH, other thread's load must have failed
641 super_load_in_progress = false;
642 }
643 }
644 }
645 return NULL;
646 }
647
648 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
649 assert(event != NULL, "invariant");
650 assert(k != NULL, "invariant");
651 assert(event->should_commit(), "invariant");
652 event->set_loadedClass(k);
653 event->set_definingClassLoader(k->class_loader_data());
654 event->set_initiatingClassLoader(init_cld);
655 event->commit();
656 }
657
658
659 // Be careful when modifying this code: once you have run
660 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
661 // you need to find_and_remove it before returning.
662 // So be careful to not exit with a CHECK_ macro betweeen these calls.
663 //
664 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
665 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
666 Handle class_loader,
667 Handle protection_domain,
668 TRAPS) {
669 assert(name != NULL && !FieldType::is_array(name) &&
670 !FieldType::is_obj(name), "invalid class name");
671
672 EventClassLoad class_load_start_event;
673
674 HandleMark hm(THREAD);
675
676 // Fix for 4474172; see evaluation for more details
677 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
678 ClassLoaderData* loader_data = register_loader(class_loader);
679 Dictionary* dictionary = loader_data->dictionary();
680 unsigned int d_hash = dictionary->compute_hash(name);
681
682 // Do lookup to see if class already exist and the protection domain
683 // has the right access
684 // This call uses find which checks protection domain already matches
685 // All subsequent calls use find_class, and set has_loaded_class so that
686 // before we return a result we call out to java to check for valid protection domain
687 // to allow returning the Klass* and add it to the pd_set if it is valid
688 {
689 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
690 if (probe != NULL) return probe;
691 }
692
693 // Non-bootstrap class loaders will call out to class loader and
694 // define via jvm/jni_DefineClass which will acquire the
695 // class loader object lock to protect against multiple threads
696 // defining the class in parallel by accident.
697 // This lock must be acquired here so the waiter will find
698 // any successful result in the SystemDictionary and not attempt
699 // the define.
700 // ParallelCapable Classloaders and the bootstrap classloader
701 // do not acquire lock here.
702 bool DoObjectLock = true;
703 if (is_parallelCapable(class_loader)) {
704 DoObjectLock = false;
705 }
706
707 unsigned int p_hash = placeholders()->compute_hash(name);
708 int p_index = placeholders()->hash_to_index(p_hash);
709
710 // Class is not in SystemDictionary so we have to do loading.
711 // Make sure we are synchronized on the class loader before we proceed
712 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
713 check_loader_lock_contention(lockObject, THREAD);
714 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
715
716 // Check again (after locking) if class already exist in SystemDictionary
717 bool class_has_been_loaded = false;
718 bool super_load_in_progress = false;
719 bool havesupername = false;
720 InstanceKlass* k = NULL;
721 PlaceholderEntry* placeholder;
722 Symbol* superclassname = NULL;
723
724 assert(THREAD->can_call_java(),
725 "can not load classes with compiler thread: class=%s, classloader=%s",
726 name->as_C_string(),
727 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
728 {
729 MutexLocker mu(SystemDictionary_lock, THREAD);
730 InstanceKlass* check = find_class(d_hash, name, dictionary);
731 if (check != NULL) {
732 // InstanceKlass is already loaded, so just return it
733 class_has_been_loaded = true;
734 k = check;
735 } else {
736 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
737 if (placeholder && placeholder->super_load_in_progress()) {
738 super_load_in_progress = true;
739 if (placeholder->havesupername() == true) {
740 superclassname = placeholder->supername();
741 havesupername = true;
742 }
743 }
744 }
745 }
746
747 // If the class is in the placeholder table, class loading is in progress
748 if (super_load_in_progress && havesupername==true) {
749 k = handle_parallel_super_load(name,
750 superclassname,
751 class_loader,
752 protection_domain,
753 lockObject, THREAD);
754 if (HAS_PENDING_EXCEPTION) {
755 return NULL;
756 }
757 if (k != NULL) {
758 class_has_been_loaded = true;
759 }
760 }
761
762 bool throw_circularity_error = false;
763 if (!class_has_been_loaded) {
764 bool load_instance_added = false;
765
766 // add placeholder entry to record loading instance class
767 // Five cases:
768 // All cases need to prevent modifying bootclasssearchpath
769 // in parallel with a classload of same classname
770 // Redefineclasses uses existence of the placeholder for the duration
771 // of the class load to prevent concurrent redefinition of not completely
772 // defined classes.
773 // case 1. traditional classloaders that rely on the classloader object lock
774 // - no other need for LOAD_INSTANCE
775 // case 2. traditional classloaders that break the classloader object lock
776 // as a deadlock workaround. Detection of this case requires that
777 // this check is done while holding the classloader object lock,
778 // and that lock is still held when calling classloader's loadClass.
779 // For these classloaders, we ensure that the first requestor
780 // completes the load and other requestors wait for completion.
781 // case 3. Bootstrap classloader - don't own objectLocker
782 // This classloader supports parallelism at the classloader level,
783 // but only allows a single load of a class/classloader pair.
784 // No performance benefit and no deadlock issues.
785 // case 4. parallelCapable user level classloaders - without objectLocker
786 // Allow parallel classloading of a class/classloader pair
787
788 {
789 MutexLocker mu(SystemDictionary_lock, THREAD);
790 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
791 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
792 if (oldprobe) {
793 // only need check_seen_thread once, not on each loop
794 // 6341374 java/lang/Instrument with -Xcomp
795 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
796 throw_circularity_error = true;
797 } else {
798 // case 1: traditional: should never see load_in_progress.
799 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
800
801 // case 3: bootstrap classloader: prevent futile classloading,
802 // wait on first requestor
803 if (class_loader.is_null()) {
804 SystemDictionary_lock->wait();
805 } else {
806 // case 2: traditional with broken classloader lock. wait on first
807 // requestor.
808 double_lock_wait(lockObject, THREAD);
809 }
810 // Check if classloading completed while we were waiting
811 InstanceKlass* check = find_class(d_hash, name, dictionary);
812 if (check != NULL) {
813 // Klass is already loaded, so just return it
814 k = check;
815 class_has_been_loaded = true;
816 }
817 // check if other thread failed to load and cleaned up
818 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
819 }
820 }
821 }
822 }
823 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
824 // case 4: parallelCapable: allow competing threads to try
825 // LOAD_INSTANCE in parallel
826
827 if (!throw_circularity_error && !class_has_been_loaded) {
828 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
829 load_instance_added = true;
830 // For class loaders that do not acquire the classloader object lock,
831 // if they did not catch another thread holding LOAD_INSTANCE,
832 // need a check analogous to the acquire ObjectLocker/find_class
833 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
834 // one final check if the load has already completed
835 // class loaders holding the ObjectLock shouldn't find the class here
836 InstanceKlass* check = find_class(d_hash, name, dictionary);
837 if (check != NULL) {
838 // Klass is already loaded, so return it after checking/adding protection domain
839 k = check;
840 class_has_been_loaded = true;
841 }
842 }
843 }
844
845 // must throw error outside of owning lock
846 if (throw_circularity_error) {
847 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
848 ResourceMark rm(THREAD);
849 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
850 }
851
852 if (!class_has_been_loaded) {
853
854 // Do actual loading
855 k = load_instance_class(name, class_loader, THREAD);
856
857 // If everything was OK (no exceptions, no null return value), and
858 // class_loader is NOT the defining loader, do a little more bookkeeping.
859 if (!HAS_PENDING_EXCEPTION && k != NULL &&
860 !oopDesc::equals(k->class_loader(), class_loader())) {
861
862 check_constraints(d_hash, k, class_loader, false, THREAD);
863
864 // Need to check for a PENDING_EXCEPTION again; check_constraints
865 // can throw and doesn't use the CHECK macro.
866 if (!HAS_PENDING_EXCEPTION) {
867 { // Grabbing the Compile_lock prevents systemDictionary updates
868 // during compilations.
869 MutexLocker mu(Compile_lock, THREAD);
870 update_dictionary(d_hash, p_index, p_hash,
871 k, class_loader, THREAD);
872 }
873
874 if (JvmtiExport::should_post_class_load()) {
875 Thread *thread = THREAD;
876 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
877 JvmtiExport::post_class_load((JavaThread *) thread, k);
878 }
879 }
880 }
881 } // load_instance_class
882
883 if (load_instance_added == true) {
884 // clean up placeholder entries for LOAD_INSTANCE success or error
885 // This brackets the SystemDictionary updates for both defining
886 // and initiating loaders
887 MutexLocker mu(SystemDictionary_lock, THREAD);
888 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
889 SystemDictionary_lock->notify_all();
890 }
891 }
892
893 if (HAS_PENDING_EXCEPTION || k == NULL) {
894 return NULL;
895 }
896 if (class_load_start_event.should_commit()) {
897 post_class_load_event(&class_load_start_event, k, loader_data);
898 }
899 #ifdef ASSERT
900 {
901 ClassLoaderData* loader_data = k->class_loader_data();
902 MutexLocker mu(SystemDictionary_lock, THREAD);
903 InstanceKlass* kk = find_class(name, loader_data);
904 assert(kk == k, "should be present in dictionary");
905 }
906 #endif
907
908 // return if the protection domain in NULL
909 if (protection_domain() == NULL) return k;
910
911 // Check the protection domain has the right access
912 if (dictionary->is_valid_protection_domain(d_hash, name,
913 protection_domain)) {
914 return k;
915 }
916
917 // Verify protection domain. If it fails an exception is thrown
918 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
919
920 return k;
921 }
922
923
924 // This routine does not lock the system dictionary.
925 //
926 // Since readers don't hold a lock, we must make sure that system
927 // dictionary entries are only removed at a safepoint (when only one
928 // thread is running), and are added to in a safe way (all links must
929 // be updated in an MT-safe manner).
930 //
931 // Callers should be aware that an entry could be added just after
932 // _dictionary->bucket(index) is read here, so the caller will not see
933 // the new entry.
934
935 Klass* SystemDictionary::find(Symbol* class_name,
936 Handle class_loader,
937 Handle protection_domain,
938 TRAPS) {
939
940 // The result of this call should be consistent with the result
941 // of the call to resolve_instance_class_or_null().
942 // See evaluation 6790209 and 4474172 for more details.
943 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
944 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
945
946 if (loader_data == NULL) {
947 // If the ClassLoaderData has not been setup,
948 // then the class loader has no entries in the dictionary.
949 return NULL;
950 }
951
952 Dictionary* dictionary = loader_data->dictionary();
953 unsigned int d_hash = dictionary->compute_hash(class_name);
954 return dictionary->find(d_hash, class_name,
955 protection_domain);
956 }
957
958
959 // Look for a loaded instance or array klass by name. Do not do any loading.
960 // return NULL in case of error.
961 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
962 Handle class_loader,
963 Handle protection_domain,
964 TRAPS) {
965 Klass* k = NULL;
966 assert(class_name != NULL, "class name must be non NULL");
967
968 if (FieldType::is_array(class_name)) {
969 // The name refers to an array. Parse the name.
970 // dimension and object_key in FieldArrayInfo are assigned as a
971 // side-effect of this call
972 FieldArrayInfo fd;
973 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
974 if (t != T_OBJECT) {
975 k = Universe::typeArrayKlassObj(t);
976 } else {
977 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
978 }
979 if (k != NULL) {
980 k = k->array_klass_or_null(fd.dimension());
981 }
982 } else {
983 k = find(class_name, class_loader, protection_domain, THREAD);
984 }
985 return k;
986 }
987
988 // Note: this method is much like resolve_from_stream, but
989 // does not publish the classes via the SystemDictionary.
990 // Handles unsafe_DefineAnonymousClass and redefineclasses
991 // RedefinedClasses do not add to the class hierarchy
992 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
993 Handle class_loader,
994 Handle protection_domain,
995 ClassFileStream* st,
996 const InstanceKlass* unsafe_anonymous_host,
997 GrowableArray<Handle>* cp_patches,
998 TRAPS) {
999
1000 EventClassLoad class_load_start_event;
1001
1002 ClassLoaderData* loader_data;
1003 if (unsafe_anonymous_host != NULL) {
1004 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1005 // as the unsafe_anonymous_host
1006 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1007 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1008 } else {
1009 loader_data = ClassLoaderData::class_loader_data(class_loader());
1010 }
1011
1012 assert(st != NULL, "invariant");
1013 assert(st->need_verify(), "invariant");
1014
1015 // Parse stream and create a klass.
1016 // Note that we do this even though this klass might
1017 // already be present in the SystemDictionary, otherwise we would not
1018 // throw potential ClassFormatErrors.
1019
1020 InstanceKlass* k = KlassFactory::create_from_stream(st,
1021 class_name,
1022 loader_data,
1023 protection_domain,
1024 unsafe_anonymous_host,
1025 cp_patches,
1026 CHECK_NULL);
1027
1028 if (unsafe_anonymous_host != NULL && k != NULL) {
1029 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1030 // so that they can be unloaded when the mirror is no longer referenced.
1031 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1032
1033 {
1034 MutexLocker mu_r(Compile_lock, THREAD);
1035
1036 // Add to class hierarchy, initialize vtables, and do possible
1037 // deoptimizations.
1038 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1039
1040 // But, do not add to dictionary.
1041
1042 // compiled code dependencies need to be validated anyway
1043 notice_modification();
1044 }
1045
1046 // Rewrite and patch constant pool here.
1047 k->link_class(CHECK_NULL);
1048 if (cp_patches != NULL) {
1049 k->constants()->patch_resolved_references(cp_patches);
1050 }
1051
1052 // If it's anonymous, initialize it now, since nobody else will.
1053 k->eager_initialize(CHECK_NULL);
1054
1055 // notify jvmti
1056 if (JvmtiExport::should_post_class_load()) {
1057 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1058 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1059 }
1060 if (class_load_start_event.should_commit()) {
1061 post_class_load_event(&class_load_start_event, k, loader_data);
1062 }
1063 }
1064 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1065 "cp_patches only found with unsafe_anonymous_host");
1066
1067 return k;
1068 }
1069
1070 // Add a klass to the system from a stream (called by jni_DefineClass and
1071 // JVM_DefineClass).
1072 // Note: class_name can be NULL. In that case we do not know the name of
1073 // the class until we have parsed the stream.
1074
1075 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1076 Handle class_loader,
1077 Handle protection_domain,
1078 ClassFileStream* st,
1079 TRAPS) {
1080
1081 HandleMark hm(THREAD);
1082
1083 // Classloaders that support parallelism, e.g. bootstrap classloader,
1084 // do not acquire lock here
1085 bool DoObjectLock = true;
1086 if (is_parallelCapable(class_loader)) {
1087 DoObjectLock = false;
1088 }
1089
1090 ClassLoaderData* loader_data = register_loader(class_loader);
1091
1092 // Make sure we are synchronized on the class loader before we proceed
1093 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1094 check_loader_lock_contention(lockObject, THREAD);
1095 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1096
1097 assert(st != NULL, "invariant");
1098
1099 // Parse the stream and create a klass.
1100 // Note that we do this even though this klass might
1101 // already be present in the SystemDictionary, otherwise we would not
1102 // throw potential ClassFormatErrors.
1103 InstanceKlass* k = NULL;
1104
1105 #if INCLUDE_CDS
1106 if (!DumpSharedSpaces) {
1107 k = SystemDictionaryShared::lookup_from_stream(class_name,
1108 class_loader,
1109 protection_domain,
1110 st,
1111 CHECK_NULL);
1112 }
1113 #endif
1114
1115 if (k == NULL) {
1116 if (st->buffer() == NULL) {
1117 return NULL;
1118 }
1119 k = KlassFactory::create_from_stream(st,
1120 class_name,
1121 loader_data,
1122 protection_domain,
1123 NULL, // unsafe_anonymous_host
1124 NULL, // cp_patches
1125 CHECK_NULL);
1126 }
1127
1128 assert(k != NULL, "no klass created");
1129 Symbol* h_name = k->name();
1130 assert(class_name == NULL || class_name == h_name, "name mismatch");
1131
1132 // Add class just loaded
1133 // If a class loader supports parallel classloading handle parallel define requests
1134 // find_or_define_instance_class may return a different InstanceKlass
1135 if (is_parallelCapable(class_loader)) {
1136 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1137 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1138 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1139 assert(defined_k != NULL, "Should have a klass if there's no exception");
1140 loader_data->add_to_deallocate_list(k);
1141 k = defined_k;
1142 }
1143 } else {
1144 define_instance_class(k, THREAD);
1145 }
1146
1147 // If defining the class throws an exception register 'k' for cleanup.
1148 if (HAS_PENDING_EXCEPTION) {
1149 assert(k != NULL, "Must have an instance klass here!");
1150 loader_data->add_to_deallocate_list(k);
1151 return NULL;
1152 }
1153
1154 // Make sure we have an entry in the SystemDictionary on success
1155 debug_only( {
1156 MutexLocker mu(SystemDictionary_lock, THREAD);
1157
1158 Klass* check = find_class(h_name, k->class_loader_data());
1159 assert(check == k, "should be present in the dictionary");
1160 } );
1161
1162 return k;
1163 }
1164
1165 #if INCLUDE_CDS
1166 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1167 int number_of_entries) {
1168 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
1169 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1170 "bad shared dictionary size.");
1171 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1172 _shared_dictionary_size, t, number_of_entries,
1173 false /* explicitly set _resizable to false */);
1174 }
1175
1176
1177 // If there is a shared dictionary, then find the entry for the
1178 // given shared system class, if any.
1179
1180 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1181 if (shared_dictionary() != NULL) {
1182 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1183 int d_index = shared_dictionary()->hash_to_index(d_hash);
1184
1185 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1186 } else {
1187 return NULL;
1188 }
1189 }
1190
1191
1192 // Load a class from the shared spaces (found through the shared system
1193 // dictionary). Force the superclass and all interfaces to be loaded.
1194 // Update the class definition to include sibling classes and no
1195 // subclasses (yet). [Classes in the shared space are not part of the
1196 // object hierarchy until loaded.]
1197
1198 InstanceKlass* SystemDictionary::load_shared_class(
1199 Symbol* class_name, Handle class_loader, TRAPS) {
1200 InstanceKlass* ik = find_shared_class(class_name);
1201 // Make sure we only return the boot class for the NULL classloader.
1202 if (ik != NULL &&
1203 ik->is_shared_boot_class() && class_loader.is_null()) {
1204 Handle protection_domain;
1205 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1206 }
1207 return NULL;
1208 }
1209
1210 // Check if a shared class can be loaded by the specific classloader:
1211 //
1212 // NULL classloader:
1213 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1214 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1215 // be defined in an unnamed module.
1216 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1217 InstanceKlass* ik,
1218 Handle class_loader, TRAPS) {
1219 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1220 "Cannot use sharing if java.base is patched");
1221 ResourceMark rm;
1222 int path_index = ik->shared_classpath_index();
1223 ClassLoaderData* loader_data = class_loader_data(class_loader);
1224 if (path_index < 0) {
1225 // path_index < 0 indicates that the class is intended for a custom loader
1226 // and should not be loaded by boot/platform/app loaders
1227 if (loader_data->is_builtin_class_loader_data()) {
1228 return false;
1229 } else {
1230 return true;
1231 }
1232 }
1233 SharedClassPathEntry* ent =
1234 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1235 if (!Universe::is_module_initialized()) {
1236 assert(ent != NULL && ent->is_modules_image(),
1237 "Loading non-bootstrap classes before the module system is initialized");
1238 assert(class_loader.is_null(), "sanity");
1239 return true;
1240 }
1241 // Get the pkg_entry from the classloader
1242 TempNewSymbol pkg_name = NULL;
1243 PackageEntry* pkg_entry = NULL;
1244 ModuleEntry* mod_entry = NULL;
1245 const char* pkg_string = NULL;
1246 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1247 if (pkg_name != NULL) {
1248 pkg_string = pkg_name->as_C_string();
1249 if (loader_data != NULL) {
1250 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1251 }
1252 if (pkg_entry != NULL) {
1253 mod_entry = pkg_entry->module();
1254 }
1255 }
1256
1257 // If the archived class is from a module that has been patched at runtime,
1258 // the class cannot be loaded from the archive.
1259 if (mod_entry != NULL && mod_entry->is_patched()) {
1260 return false;
1261 }
1262
1263 if (class_loader.is_null()) {
1264 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1265 // The NULL classloader can load archived class originated from the
1266 // "modules" jimage and the -Xbootclasspath/a. For class from the
1267 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1268 // by the NULL classloader.
1269 if (mod_entry != NULL) {
1270 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1271 // ModuleEntry's location agrees with the archived class' origination.
1272 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1273 return true; // Module class from the "module" jimage
1274 }
1275 }
1276
1277 // If the archived class is not from the "module" jimage, the class can be
1278 // loaded by the NULL classloader if
1279 //
1280 // 1. the class is from the unamed package
1281 // 2. or, the class is not from a module defined in the NULL classloader
1282 // 3. or, the class is from an unamed module
1283 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1284 // the class is from the -Xbootclasspath/a
1285 if (pkg_string == NULL ||
1286 pkg_entry == NULL ||
1287 pkg_entry->in_unnamed_module()) {
1288 assert(mod_entry == NULL ||
1289 mod_entry == loader_data->unnamed_module(),
1290 "the unnamed module is not defined in the classloader");
1291 return true;
1292 }
1293 }
1294 return false;
1295 } else {
1296 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1297 ik, class_loader, pkg_string, pkg_name,
1298 pkg_entry, mod_entry, CHECK_(false));
1299 return res;
1300 }
1301 }
1302
1303 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1304 Handle class_loader,
1305 Handle protection_domain, TRAPS) {
1306
1307 if (ik != NULL) {
1308 Symbol* class_name = ik->name();
1309
1310 bool visible = is_shared_class_visible(
1311 class_name, ik, class_loader, CHECK_NULL);
1312 if (!visible) {
1313 return NULL;
1314 }
1315
1316 // Resolve the superclass and interfaces. They must be the same
1317 // as in dump time, because the layout of <ik> depends on
1318 // the specific layout of ik->super() and ik->local_interfaces().
1319 //
1320 // If unexpected superclass or interfaces are found, we cannot
1321 // load <ik> from the shared archive.
1322
1323 if (ik->super() != NULL) {
1324 Symbol* cn = ik->super()->name();
1325 Klass *s = resolve_super_or_fail(class_name, cn,
1326 class_loader, protection_domain, true, CHECK_NULL);
1327 if (s != ik->super()) {
1328 // The dynamically resolved super class is not the same as the one we used during dump time,
1329 // so we cannot use ik.
1330 return NULL;
1331 } else {
1332 assert(s->is_shared(), "must be");
1333 }
1334 }
1335
1336 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1337 int num_interfaces = interfaces->length();
1338 for (int index = 0; index < num_interfaces; index++) {
1339 InstanceKlass* k = interfaces->at(index);
1340 Symbol* name = k->name();
1341 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1342 if (k != i) {
1343 // The dynamically resolved interface class is not the same as the one we used during dump time,
1344 // so we cannot use ik.
1345 return NULL;
1346 } else {
1347 assert(i->is_shared(), "must be");
1348 }
1349 }
1350
1351 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1352 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1353 if (new_ik != NULL) {
1354 // The class is changed by CFLH. Return the new class. The shared class is
1355 // not used.
1356 return new_ik;
1357 }
1358
1359 // Adjust methods to recover missing data. They need addresses for
1360 // interpreter entry points and their default native method address
1361 // must be reset.
1362
1363 // Updating methods must be done under a lock so multiple
1364 // threads don't update these in parallel
1365 //
1366 // Shared classes are all currently loaded by either the bootstrap or
1367 // internal parallel class loaders, so this will never cause a deadlock
1368 // on a custom class loader lock.
1369
1370 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1371 {
1372 HandleMark hm(THREAD);
1373 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1374 check_loader_lock_contention(lockObject, THREAD);
1375 ObjectLocker ol(lockObject, THREAD, true);
1376 // prohibited package check assumes all classes loaded from archive call
1377 // restore_unshareable_info which calls ik->set_package()
1378 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1379 }
1380
1381 ik->print_class_load_logging(loader_data, NULL, NULL);
1382
1383 // For boot loader, ensure that GetSystemPackage knows that a class in this
1384 // package was loaded.
1385 if (class_loader.is_null()) {
1386 int path_index = ik->shared_classpath_index();
1387 ResourceMark rm;
1388 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1389 }
1390
1391 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1392 // Only dump the classes that can be stored into CDS archive
1393 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1394 ResourceMark rm(THREAD);
1395 classlist_file->print_cr("%s", ik->name()->as_C_string());
1396 classlist_file->flush();
1397 }
1398 }
1399
1400 // notify a class loaded from shared object
1401 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1402
1403 ik->set_has_passed_fingerprint_check(false);
1404 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1405 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1406 uint64_t cds_fp = ik->get_stored_fingerprint();
1407 if (aot_fp != 0 && aot_fp == cds_fp) {
1408 // This class matches with a class saved in an AOT library
1409 ik->set_has_passed_fingerprint_check(true);
1410 } else {
1411 ResourceMark rm;
1412 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1413 }
1414 }
1415 }
1416 return ik;
1417 }
1418
1419 void SystemDictionary::clear_invoke_method_table() {
1420 SymbolPropertyEntry* spe = NULL;
1421 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1422 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1423 while (p != NULL) {
1424 spe = p;
1425 p = p->next();
1426 _invoke_method_table->free_entry(spe);
1427 }
1428 }
1429 }
1430 #endif // INCLUDE_CDS
1431
1432 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1433
1434 if (class_loader.is_null()) {
1435 ResourceMark rm;
1436 PackageEntry* pkg_entry = NULL;
1437 bool search_only_bootloader_append = false;
1438 ClassLoaderData *loader_data = class_loader_data(class_loader);
1439
1440 // Find the package in the boot loader's package entry table.
1441 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1442 if (pkg_name != NULL) {
1443 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1444 }
1445
1446 // Prior to attempting to load the class, enforce the boot loader's
1447 // visibility boundaries.
1448 if (!Universe::is_module_initialized()) {
1449 // During bootstrapping, prior to module initialization, any
1450 // class attempting to be loaded must be checked against the
1451 // java.base packages in the boot loader's PackageEntryTable.
1452 // No class outside of java.base is allowed to be loaded during
1453 // this bootstrapping window.
1454 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1455 // Class is either in the unnamed package or in
1456 // a named package within the unnamed module. Either
1457 // case is outside of java.base, do not attempt to
1458 // load the class post java.base definition. If
1459 // java.base has not been defined, let the class load
1460 // and its package will be checked later by
1461 // ModuleEntryTable::verify_javabase_packages.
1462 if (ModuleEntryTable::javabase_defined()) {
1463 return NULL;
1464 }
1465 } else {
1466 // Check that the class' package is defined within java.base.
1467 ModuleEntry* mod_entry = pkg_entry->module();
1468 Symbol* mod_entry_name = mod_entry->name();
1469 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1470 return NULL;
1471 }
1472 }
1473 } else {
1474 // After the module system has been initialized, check if the class'
1475 // package is in a module defined to the boot loader.
1476 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1477 // Class is either in the unnamed package, in a named package
1478 // within a module not defined to the boot loader or in a
1479 // a named package within the unnamed module. In all cases,
1480 // limit visibility to search for the class only in the boot
1481 // loader's append path.
1482 search_only_bootloader_append = true;
1483 }
1484 }
1485
1486 // Prior to bootstrapping's module initialization, never load a class outside
1487 // of the boot loader's module path
1488 assert(Universe::is_module_initialized() ||
1489 !search_only_bootloader_append,
1490 "Attempt to load a class outside of boot loader's module path");
1491
1492 // Search for classes in the CDS archive.
1493 InstanceKlass* k = NULL;
1494 {
1495 #if INCLUDE_CDS
1496 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1497 k = load_shared_class(class_name, class_loader, THREAD);
1498 #endif
1499 }
1500
1501 if (k == NULL) {
1502 // Use VM class loader
1503 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1504 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1505 }
1506
1507 // find_or_define_instance_class may return a different InstanceKlass
1508 if (k != NULL) {
1509 InstanceKlass* defined_k =
1510 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1511 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1512 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1513 assert(defined_k != NULL, "Should have a klass if there's no exception");
1514 loader_data->add_to_deallocate_list(k);
1515 k = defined_k;
1516 } else if (HAS_PENDING_EXCEPTION) {
1517 loader_data->add_to_deallocate_list(k);
1518 return NULL;
1519 }
1520 }
1521 return k;
1522 } else {
1523 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1524 ResourceMark rm(THREAD);
1525
1526 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1527 JavaThread* jt = (JavaThread*) THREAD;
1528
1529 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1530 ClassLoader::perf_app_classload_selftime(),
1531 ClassLoader::perf_app_classload_count(),
1532 jt->get_thread_stat()->perf_recursion_counts_addr(),
1533 jt->get_thread_stat()->perf_timers_addr(),
1534 PerfClassTraceTime::CLASS_LOAD);
1535
1536 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1537 // Translate to external class name format, i.e., convert '/' chars to '.'
1538 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1539
1540 JavaValue result(T_OBJECT);
1541
1542 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1543
1544 // Call public unsynchronized loadClass(String) directly for all class loaders.
1545 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1546 // acquire a class-name based lock rather than the class loader object lock.
1547 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1548 JavaCalls::call_virtual(&result,
1549 class_loader,
1550 spec_klass,
1551 vmSymbols::loadClass_name(),
1552 vmSymbols::string_class_signature(),
1553 string,
1554 CHECK_NULL);
1555
1556 assert(result.get_type() == T_OBJECT, "just checking");
1557 oop obj = (oop) result.get_jobject();
1558
1559 // Primitive classes return null since forName() can not be
1560 // used to obtain any of the Class objects representing primitives or void
1561 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1562 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1563 // For user defined Java class loaders, check that the name returned is
1564 // the same as that requested. This check is done for the bootstrap
1565 // loader when parsing the class file.
1566 if (class_name == k->name()) {
1567 return k;
1568 }
1569 }
1570 // Class is not found or has the wrong name, return NULL
1571 return NULL;
1572 }
1573 }
1574
1575 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1576 EventClassDefine event;
1577 if (event.should_commit()) {
1578 event.set_definedClass(k);
1579 event.set_definingClassLoader(def_cld);
1580 event.commit();
1581 }
1582 }
1583
1584 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1585
1586 HandleMark hm(THREAD);
1587 ClassLoaderData* loader_data = k->class_loader_data();
1588 Handle class_loader_h(THREAD, loader_data->class_loader());
1589
1590 // for bootstrap and other parallel classloaders don't acquire lock,
1591 // use placeholder token
1592 // If a parallelCapable class loader calls define_instance_class instead of
1593 // find_or_define_instance_class to get here, we have a timing
1594 // hole with systemDictionary updates and check_constraints
1595 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1596 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1597 compute_loader_lock_object(class_loader_h, THREAD)),
1598 "define called without lock");
1599 }
1600
1601 // Check class-loading constraints. Throw exception if violation is detected.
1602 // Grabs and releases SystemDictionary_lock
1603 // The check_constraints/find_class call and update_dictionary sequence
1604 // must be "atomic" for a specific class/classloader pair so we never
1605 // define two different instanceKlasses for that class/classloader pair.
1606 // Existing classloaders will call define_instance_class with the
1607 // classloader lock held
1608 // Parallel classloaders will call find_or_define_instance_class
1609 // which will require a token to perform the define class
1610 Symbol* name_h = k->name();
1611 Dictionary* dictionary = loader_data->dictionary();
1612 unsigned int d_hash = dictionary->compute_hash(name_h);
1613 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1614
1615 // Register class just loaded with class loader (placed in Vector)
1616 // Note we do this before updating the dictionary, as this can
1617 // fail with an OutOfMemoryError (if it does, we will *not* put this
1618 // class in the dictionary and will not update the class hierarchy).
1619 // JVMTI FollowReferences needs to find the classes this way.
1620 if (k->class_loader() != NULL) {
1621 methodHandle m(THREAD, Universe::loader_addClass_method());
1622 JavaValue result(T_VOID);
1623 JavaCallArguments args(class_loader_h);
1624 args.push_oop(Handle(THREAD, k->java_mirror()));
1625 JavaCalls::call(&result, m, &args, CHECK);
1626 }
1627
1628 // Add the new class. We need recompile lock during update of CHA.
1629 {
1630 unsigned int p_hash = placeholders()->compute_hash(name_h);
1631 int p_index = placeholders()->hash_to_index(p_hash);
1632
1633 MutexLocker mu_r(Compile_lock, THREAD);
1634
1635 // Add to class hierarchy, initialize vtables, and do possible
1636 // deoptimizations.
1637 add_to_hierarchy(k, CHECK); // No exception, but can block
1638
1639 // Add to systemDictionary - so other classes can see it.
1640 // Grabs and releases SystemDictionary_lock
1641 update_dictionary(d_hash, p_index, p_hash,
1642 k, class_loader_h, THREAD);
1643 }
1644 k->eager_initialize(THREAD);
1645
1646 // notify jvmti
1647 if (JvmtiExport::should_post_class_load()) {
1648 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1649 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1650
1651 }
1652 post_class_define_event(k, loader_data);
1653 }
1654
1655 // Support parallel classloading
1656 // All parallel class loaders, including bootstrap classloader
1657 // lock a placeholder entry for this class/class_loader pair
1658 // to allow parallel defines of different classes for this class loader
1659 // With AllowParallelDefine flag==true, in case they do not synchronize around
1660 // FindLoadedClass/DefineClass, calls, we check for parallel
1661 // loading for them, wait if a defineClass is in progress
1662 // and return the initial requestor's results
1663 // This flag does not apply to the bootstrap classloader.
1664 // With AllowParallelDefine flag==false, call through to define_instance_class
1665 // which will throw LinkageError: duplicate class definition.
1666 // False is the requested default.
1667 // For better performance, the class loaders should synchronize
1668 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1669 // potentially waste time reading and parsing the bytestream.
1670 // Note: VM callers should ensure consistency of k/class_name,class_loader
1671 // Be careful when modifying this code: once you have run
1672 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1673 // you need to find_and_remove it before returning.
1674 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1675 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1676 InstanceKlass* k, TRAPS) {
1677
1678 Symbol* name_h = k->name(); // passed in class_name may be null
1679 ClassLoaderData* loader_data = class_loader_data(class_loader);
1680 Dictionary* dictionary = loader_data->dictionary();
1681
1682 unsigned int d_hash = dictionary->compute_hash(name_h);
1683
1684 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1685 unsigned int p_hash = placeholders()->compute_hash(name_h);
1686 int p_index = placeholders()->hash_to_index(p_hash);
1687 PlaceholderEntry* probe;
1688
1689 {
1690 MutexLocker mu(SystemDictionary_lock, THREAD);
1691 // First check if class already defined
1692 if (is_parallelDefine(class_loader)) {
1693 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1694 if (check != NULL) {
1695 return check;
1696 }
1697 }
1698
1699 // Acquire define token for this class/classloader
1700 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1701 // Wait if another thread defining in parallel
1702 // All threads wait - even those that will throw duplicate class: otherwise
1703 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1704 // if other thread has not finished updating dictionary
1705 while (probe->definer() != NULL) {
1706 SystemDictionary_lock->wait();
1707 }
1708 // Only special cases allow parallel defines and can use other thread's results
1709 // Other cases fall through, and may run into duplicate defines
1710 // caught by finding an entry in the SystemDictionary
1711 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1712 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1713 SystemDictionary_lock->notify_all();
1714 #ifdef ASSERT
1715 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1716 assert(check != NULL, "definer missed recording success");
1717 #endif
1718 return probe->instance_klass();
1719 } else {
1720 // This thread will define the class (even if earlier thread tried and had an error)
1721 probe->set_definer(THREAD);
1722 }
1723 }
1724
1725 define_instance_class(k, THREAD);
1726
1727 Handle linkage_exception = Handle(); // null handle
1728
1729 // definer must notify any waiting threads
1730 {
1731 MutexLocker mu(SystemDictionary_lock, THREAD);
1732 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1733 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1734 if (probe != NULL) {
1735 if (HAS_PENDING_EXCEPTION) {
1736 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1737 CLEAR_PENDING_EXCEPTION;
1738 } else {
1739 probe->set_instance_klass(k);
1740 }
1741 probe->set_definer(NULL);
1742 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1743 SystemDictionary_lock->notify_all();
1744 }
1745 }
1746
1747 // Can't throw exception while holding lock due to rank ordering
1748 if (linkage_exception() != NULL) {
1749 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1750 }
1751
1752 return k;
1753 }
1754
1755 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1756 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1757 if (class_loader.is_null()) {
1758 return Handle(THREAD, _system_loader_lock_obj);
1759 } else {
1760 return class_loader;
1761 }
1762 }
1763
1764 // This method is added to check how often we have to wait to grab loader
1765 // lock. The results are being recorded in the performance counters defined in
1766 // ClassLoader::_sync_systemLoaderLockContentionRate and
1767 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1768 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1769 if (!UsePerfData) {
1770 return;
1771 }
1772
1773 assert(!loader_lock.is_null(), "NULL lock object");
1774
1775 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1776 == ObjectSynchronizer::owner_other) {
1777 // contention will likely happen, so increment the corresponding
1778 // contention counter.
1779 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1780 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1781 } else {
1782 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1783 }
1784 }
1785 }
1786
1787 // ----------------------------------------------------------------------------
1788 // Lookup
1789
1790 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1791 Symbol* class_name,
1792 Dictionary* dictionary) {
1793 assert_locked_or_safepoint(SystemDictionary_lock);
1794 int index = dictionary->hash_to_index(hash);
1795 return dictionary->find_class(index, hash, class_name);
1796 }
1797
1798
1799 // Basic find on classes in the midst of being loaded
1800 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1801 ClassLoaderData* loader_data) {
1802 assert_locked_or_safepoint(SystemDictionary_lock);
1803 unsigned int p_hash = placeholders()->compute_hash(class_name);
1804 int p_index = placeholders()->hash_to_index(p_hash);
1805 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1806 }
1807
1808
1809 // Used for assertions and verification only
1810 // Precalculating the hash and index is an optimization because there are many lookups
1811 // before adding the class.
1812 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1813 assert_locked_or_safepoint(SystemDictionary_lock);
1814 #ifndef ASSERT
1815 guarantee(VerifyBeforeGC ||
1816 VerifyDuringGC ||
1817 VerifyBeforeExit ||
1818 VerifyDuringStartup ||
1819 VerifyAfterGC, "too expensive");
1820 #endif
1821
1822 Dictionary* dictionary = loader_data->dictionary();
1823 unsigned int d_hash = dictionary->compute_hash(class_name);
1824 return find_class(d_hash, class_name, dictionary);
1825 }
1826
1827
1828 // ----------------------------------------------------------------------------
1829 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1830 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1831 // before a new class is used.
1832
1833 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1834 assert(k != NULL, "just checking");
1835 assert_locked_or_safepoint(Compile_lock);
1836
1837 // Link into hierachy. Make sure the vtables are initialized before linking into
1838 k->append_to_sibling_list(); // add to superklass/sibling list
1839 k->process_interfaces(THREAD); // handle all "implements" declarations
1840 k->set_init_state(InstanceKlass::loaded);
1841 // Now flush all code that depended on old class hierarchy.
1842 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1843 // Also, first reinitialize vtable because it may have gotten out of synch
1844 // while the new class wasn't connected to the class hierarchy.
1845 CodeCache::flush_dependents_on(k);
1846 }
1847
1848 // ----------------------------------------------------------------------------
1849 // GC support
1850
1851 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1852 // Note: anonymous classes are not in the SD.
1853 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1854 bool do_cleaning) {
1855
1856 bool unloading_occurred;
1857 {
1858 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1859
1860 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1861 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1862 if (unloading_occurred) {
1863 JFR_ONLY(Jfr::on_unloading_classes();)
1864 ClassLoaderDataGraph::clean_module_and_package_info();
1865 }
1866 }
1867
1868 // TODO: just return if !unloading_occurred.
1869 if (unloading_occurred) {
1870 {
1871 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
1872 // Check if there's work to do in the SymbolTable
1873 SymbolTable::do_check_concurrent_work();
1874 }
1875
1876 {
1877 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1878 constraints()->purge_loader_constraints();
1879 resolution_errors()->purge_resolution_errors();
1880 }
1881 }
1882
1883 {
1884 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1885 // Oops referenced by the protection domain cache table may get unreachable independently
1886 // of the class loader (eg. cached protection domain oops). So we need to
1887 // explicitly unlink them here.
1888 _pd_cache_table->trigger_cleanup();
1889 }
1890
1891 if (do_cleaning) {
1892 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1893 ResolvedMethodTable::trigger_cleanup();
1894 }
1895
1896 return unloading_occurred;
1897 }
1898
1899 void SystemDictionary::oops_do(OopClosure* f) {
1900 f->do_oop(&_java_system_loader);
1901 f->do_oop(&_java_platform_loader);
1902 f->do_oop(&_system_loader_lock_obj);
1903 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1904
1905 // Visit extra methods
1906 invoke_method_table()->oops_do(f);
1907 }
1908
1909 // CDS: scan and relocate all classes in the system dictionary.
1910 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1911 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1912 }
1913
1914 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1915 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1916 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1917 it->push(well_known_klass_addr((WKID)id));
1918 }
1919 }
1920
1921 void SystemDictionary::methods_do(void f(Method*)) {
1922 // Walk methods in loaded classes
1923 MutexLocker ml(ClassLoaderDataGraph_lock);
1924 ClassLoaderDataGraph::methods_do(f);
1925 // Walk method handle intrinsics
1926 invoke_method_table()->methods_do(f);
1927 }
1928
1929 class RemoveClassesClosure : public CLDClosure {
1930 public:
1931 void do_cld(ClassLoaderData* cld) {
1932 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1933 cld->dictionary()->remove_classes_in_error_state();
1934 }
1935 }
1936 };
1937
1938 void SystemDictionary::remove_classes_in_error_state() {
1939 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1940 RemoveClassesClosure rcc;
1941 MutexLocker ml(ClassLoaderDataGraph_lock);
1942 ClassLoaderDataGraph::cld_do(&rcc);
1943 }
1944
1945 // ----------------------------------------------------------------------------
1946 // Initialization
1947
1948 void SystemDictionary::initialize(TRAPS) {
1949 // Allocate arrays
1950 _placeholders = new PlaceholderTable(_placeholder_table_size);
1951 _number_of_modifications = 0;
1952 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1953 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1954 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1955 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1956
1957 // Allocate private object used as system class loader lock
1958 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1959 // Initialize basic classes
1960 resolve_well_known_classes(CHECK);
1961 }
1962
1963 // Compact table of directions on the initialization of klasses:
1964 static const short wk_init_info[] = {
1965 #define WK_KLASS_INIT_INFO(name, symbol) \
1966 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1967
1968 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1969 #undef WK_KLASS_INIT_INFO
1970 0
1971 };
1972
1973 #ifdef ASSERT
1974 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1975 for (int i = 0; ; i++) {
1976 int sid = wk_init_info[i];
1977 if (sid == 0) {
1978 break;
1979 }
1980 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1981 if (class_name == symbol) {
1982 return true;
1983 }
1984 }
1985 return false;
1986 }
1987 #endif
1988
1989 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1990 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1991 int sid = wk_init_info[id - FIRST_WKID];
1992 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1993 InstanceKlass** klassp = &_well_known_klasses[id];
1994
1995
1996 #if INCLUDE_JVMCI
1997 if (id >= FIRST_JVMCI_WKID) {
1998 assert(EnableJVMCI, "resolve JVMCI classes only when EnableJVMCI is true");
1999 }
2000 #endif
2001
2002 if ((*klassp) == NULL) {
2003 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
2004 (*klassp) = InstanceKlass::cast(k);
2005 }
2006 return ((*klassp) != NULL);
2007 }
2008
2009 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2010 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2011 for (int id = (int)start_id; id < (int)limit_id; id++) {
2012 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2013 resolve_wk_klass((WKID)id, CHECK);
2014 }
2015
2016 // move the starting value forward to the limit:
2017 start_id = limit_id;
2018 }
2019
2020 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2021 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
2022
2023 // Create the ModuleEntry for java.base. This call needs to be done here,
2024 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2025 ClassLoader::classLoader_init2(CHECK);
2026
2027 // Preload commonly used klasses
2028 WKID scan = FIRST_WKID;
2029 // first do Object, then String, Class
2030 #if INCLUDE_CDS
2031 if (UseSharedSpaces) {
2032 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2033
2034 // It's unsafe to access the archived heap regions before they
2035 // are fixed up, so we must do the fixup as early as possible
2036 // before the archived java objects are accessed by functions
2037 // such as java_lang_Class::restore_archived_mirror and
2038 // ConstantPool::restore_unshareable_info (restores the archived
2039 // resolved_references array object).
2040 //
2041 // HeapShared::fixup_mapped_heap_regions() fills the empty
2042 // spaces in the archived heap regions and may use
2043 // SystemDictionary::Object_klass(), so we can do this only after
2044 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2045 // call. No mirror objects are accessed/restored in the above call.
2046 // Mirrors are restored after java.lang.Class is loaded.
2047 HeapShared::fixup_mapped_heap_regions();
2048
2049 // Initialize the constant pool for the Object_class
2050 Object_klass()->constants()->restore_unshareable_info(CHECK);
2051 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2052 } else
2053 #endif
2054 {
2055 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2056 }
2057
2058 // Calculate offsets for String and Class classes since they are loaded and
2059 // can be used after this point.
2060 java_lang_String::compute_offsets();
2061 java_lang_Class::compute_offsets();
2062
2063 // Fixup mirrors for classes loaded before java.lang.Class.
2064 // These calls iterate over the objects currently in the perm gen
2065 // so calling them at this point is matters (not before when there
2066 // are fewer objects and not later after there are more objects
2067 // in the perm gen.
2068 Universe::initialize_basic_type_mirrors(CHECK);
2069 Universe::fixup_mirrors(CHECK);
2070
2071 // do a bunch more:
2072 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2073
2074 // Preload ref klasses and set reference types
2075 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2076 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2077
2078 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2079 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2080 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2081 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2082 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2083
2084 // JSR 292 classes
2085 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2086 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2087 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2088 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2089 WKID last = NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID);
2090 resolve_wk_klasses_until(last, scan, CHECK);
2091
2092 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2093 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2094 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2095 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2096 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2097 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2098 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2099 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2100 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2101 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2102
2103 { // Compute whether we should use checkPackageAccess or NOT
2104 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2105 _has_checkPackageAccess = (method != NULL);
2106 }
2107
2108 if (UseSharedSpaces) {
2109 assert(JvmtiEnvBase::get_phase() <= JVMTI_PHASE_PRIMORDIAL,
2110 "All well known classes must be resolved in JVMTI_PHASE_PRIMORDIAL or before");
2111 for (int i = FIRST_WKID; i < last; i++) {
2112 InstanceKlass* k = _well_known_klasses[i];
2113 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2114 }
2115 }
2116 }
2117
2118 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2119 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2120 BasicType SystemDictionary::box_klass_type(Klass* k) {
2121 assert(k != NULL, "");
2122 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2123 if (_box_klasses[i] == k)
2124 return (BasicType)i;
2125 }
2126 return T_OBJECT;
2127 }
2128
2129 // Constraints on class loaders. The details of the algorithm can be
2130 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2131 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2132 // that the dictionary needs to maintain a set of contraints that
2133 // must be satisfied by all classes in the dictionary.
2134 // if defining is true, then LinkageError if already in dictionary
2135 // if initiating loader, then ok if InstanceKlass matches existing entry
2136
2137 void SystemDictionary::check_constraints(unsigned int d_hash,
2138 InstanceKlass* k,
2139 Handle class_loader,
2140 bool defining,
2141 TRAPS) {
2142 ResourceMark rm(THREAD);
2143 stringStream ss;
2144 bool throwException = false;
2145
2146 {
2147 Symbol *name = k->name();
2148 ClassLoaderData *loader_data = class_loader_data(class_loader);
2149
2150 MutexLocker mu(SystemDictionary_lock, THREAD);
2151
2152 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2153 if (check != NULL) {
2154 // If different InstanceKlass - duplicate class definition,
2155 // else - ok, class loaded by a different thread in parallel.
2156 // We should only have found it if it was done loading and ok to use.
2157 // The dictionary only holds instance classes, placeholders
2158 // also hold array classes.
2159
2160 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2161 if ((defining == true) || (k != check)) {
2162 throwException = true;
2163 ss.print("loader %s", loader_data->loader_name_and_id());
2164 ss.print(" attempted duplicate %s definition for %s. (%s)",
2165 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2166 } else {
2167 return;
2168 }
2169 }
2170
2171 #ifdef ASSERT
2172 Symbol* ph_check = find_placeholder(name, loader_data);
2173 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2174 #endif
2175
2176 if (throwException == false) {
2177 if (constraints()->check_or_update(k, class_loader, name) == false) {
2178 throwException = true;
2179 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2180 ss.print(" wants to load %s %s.",
2181 k->external_kind(), k->external_name());
2182 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2183 if (existing_klass->class_loader() != class_loader()) {
2184 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2185 existing_klass->external_kind(),
2186 existing_klass->class_loader_data()->loader_name_and_id(),
2187 existing_klass->class_in_module_of_loader(false, true));
2188 } else {
2189 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2190 }
2191 }
2192 }
2193 }
2194
2195 // Throw error now if needed (cannot throw while holding
2196 // SystemDictionary_lock because of rank ordering)
2197 if (throwException == true) {
2198 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2199 }
2200 }
2201
2202 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2203 // have been called.
2204 void SystemDictionary::update_dictionary(unsigned int d_hash,
2205 int p_index, unsigned int p_hash,
2206 InstanceKlass* k,
2207 Handle class_loader,
2208 TRAPS) {
2209 // Compile_lock prevents systemDictionary updates during compilations
2210 assert_locked_or_safepoint(Compile_lock);
2211 Symbol* name = k->name();
2212 ClassLoaderData *loader_data = class_loader_data(class_loader);
2213
2214 {
2215 MutexLocker mu1(SystemDictionary_lock, THREAD);
2216
2217 // See whether biased locking is enabled and if so set it for this
2218 // klass.
2219 // Note that this must be done past the last potential blocking
2220 // point / safepoint. We enable biased locking lazily using a
2221 // VM_Operation to iterate the SystemDictionary and installing the
2222 // biasable mark word into each InstanceKlass's prototype header.
2223 // To avoid race conditions where we accidentally miss enabling the
2224 // optimization for one class in the process of being added to the
2225 // dictionary, we must not safepoint after the test of
2226 // BiasedLocking::enabled().
2227 if (UseBiasedLocking && BiasedLocking::enabled()) {
2228 // Set biased locking bit for all loaded classes; it will be
2229 // cleared if revocation occurs too often for this type
2230 // NOTE that we must only do this when the class is initally
2231 // defined, not each time it is referenced from a new class loader
2232 if (oopDesc::equals(k->class_loader(), class_loader())) {
2233 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2234 }
2235 }
2236
2237 // Make a new dictionary entry.
2238 Dictionary* dictionary = loader_data->dictionary();
2239 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2240 if (sd_check == NULL) {
2241 dictionary->add_klass(d_hash, name, k);
2242 notice_modification();
2243 }
2244 #ifdef ASSERT
2245 sd_check = find_class(d_hash, name, dictionary);
2246 assert (sd_check != NULL, "should have entry in dictionary");
2247 // Note: there may be a placeholder entry: for circularity testing
2248 // or for parallel defines
2249 #endif
2250 SystemDictionary_lock->notify_all();
2251 }
2252 }
2253
2254
2255 // Try to find a class name using the loader constraints. The
2256 // loader constraints might know about a class that isn't fully loaded
2257 // yet and these will be ignored.
2258 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2259 Symbol* class_name, Handle class_loader, TRAPS) {
2260
2261 // First see if it has been loaded directly.
2262 // Force the protection domain to be null. (This removes protection checks.)
2263 Handle no_protection_domain;
2264 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2265 no_protection_domain, CHECK_NULL);
2266 if (klass != NULL)
2267 return klass;
2268
2269 // Now look to see if it has been loaded elsewhere, and is subject to
2270 // a loader constraint that would require this loader to return the
2271 // klass that is already loaded.
2272 if (FieldType::is_array(class_name)) {
2273 // For array classes, their Klass*s are not kept in the
2274 // constraint table. The element Klass*s are.
2275 FieldArrayInfo fd;
2276 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2277 if (t != T_OBJECT) {
2278 klass = Universe::typeArrayKlassObj(t);
2279 } else {
2280 MutexLocker mu(SystemDictionary_lock, THREAD);
2281 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2282 }
2283 // If element class already loaded, allocate array klass
2284 if (klass != NULL) {
2285 klass = klass->array_klass_or_null(fd.dimension());
2286 }
2287 } else {
2288 MutexLocker mu(SystemDictionary_lock, THREAD);
2289 // Non-array classes are easy: simply check the constraint table.
2290 klass = constraints()->find_constrained_klass(class_name, class_loader);
2291 }
2292
2293 return klass;
2294 }
2295
2296
2297 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2298 Handle class_loader1,
2299 Handle class_loader2,
2300 Thread* THREAD) {
2301 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2302 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2303
2304 Symbol* constraint_name = NULL;
2305 // Needs to be in same scope as constraint_name in case a Symbol is created and
2306 // assigned to constraint_name.
2307 FieldArrayInfo fd;
2308 if (!FieldType::is_array(class_name)) {
2309 constraint_name = class_name;
2310 } else {
2311 // For array classes, their Klass*s are not kept in the
2312 // constraint table. The element classes are.
2313 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2314 // primitive types always pass
2315 if (t != T_OBJECT) {
2316 return true;
2317 } else {
2318 constraint_name = fd.object_key();
2319 }
2320 }
2321
2322 Dictionary* dictionary1 = loader_data1->dictionary();
2323 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2324
2325 Dictionary* dictionary2 = loader_data2->dictionary();
2326 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2327
2328 {
2329 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2330 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2331 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2332 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2333 klass2, class_loader2);
2334 }
2335 }
2336
2337 // Add entry to resolution error table to record the error when the first
2338 // attempt to resolve a reference to a class has failed.
2339 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2340 Symbol* error, Symbol* message) {
2341 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2342 int index = resolution_errors()->hash_to_index(hash);
2343 {
2344 MutexLocker ml(SystemDictionary_lock, Thread::current());
2345 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2346 }
2347 }
2348
2349 // Delete a resolution error for RedefineClasses for a constant pool is going away
2350 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2351 resolution_errors()->delete_entry(pool);
2352 }
2353
2354 // Lookup resolution error table. Returns error if found, otherwise NULL.
2355 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2356 Symbol** message) {
2357 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2358 int index = resolution_errors()->hash_to_index(hash);
2359 {
2360 MutexLocker ml(SystemDictionary_lock, Thread::current());
2361 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2362 if (entry != NULL) {
2363 *message = entry->message();
2364 return entry->error();
2365 } else {
2366 return NULL;
2367 }
2368 }
2369 }
2370
2371
2372 // Signature constraints ensure that callers and callees agree about
2373 // the meaning of type names in their signatures. This routine is the
2374 // intake for constraints. It collects them from several places:
2375 //
2376 // * LinkResolver::resolve_method (if check_access is true) requires
2377 // that the resolving class (the caller) and the defining class of
2378 // the resolved method (the callee) agree on each type in the
2379 // method's signature.
2380 //
2381 // * LinkResolver::resolve_interface_method performs exactly the same
2382 // checks.
2383 //
2384 // * LinkResolver::resolve_field requires that the constant pool
2385 // attempting to link to a field agree with the field's defining
2386 // class about the type of the field signature.
2387 //
2388 // * klassVtable::initialize_vtable requires that, when a class
2389 // overrides a vtable entry allocated by a superclass, that the
2390 // overriding method (i.e., the callee) agree with the superclass
2391 // on each type in the method's signature.
2392 //
2393 // * klassItable::initialize_itable requires that, when a class fills
2394 // in its itables, for each non-abstract method installed in an
2395 // itable, the method (i.e., the callee) agree with the interface
2396 // on each type in the method's signature.
2397 //
2398 // All those methods have a boolean (check_access, checkconstraints)
2399 // which turns off the checks. This is used from specialized contexts
2400 // such as bootstrapping, dumping, and debugging.
2401 //
2402 // No direct constraint is placed between the class and its
2403 // supertypes. Constraints are only placed along linked relations
2404 // between callers and callees. When a method overrides or implements
2405 // an abstract method in a supertype (superclass or interface), the
2406 // constraints are placed as if the supertype were the caller to the
2407 // overriding method. (This works well, since callers to the
2408 // supertype have already established agreement between themselves and
2409 // the supertype.) As a result of all this, a class can disagree with
2410 // its supertype about the meaning of a type name, as long as that
2411 // class neither calls a relevant method of the supertype, nor is
2412 // called (perhaps via an override) from the supertype.
2413 //
2414 //
2415 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2416 //
2417 // Make sure all class components (including arrays) in the given
2418 // signature will be resolved to the same class in both loaders.
2419 // Returns the name of the type that failed a loader constraint check, or
2420 // NULL if no constraint failed. No exception except OOME is thrown.
2421 // Arrays are not added to the loader constraint table, their elements are.
2422 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2423 Handle loader1, Handle loader2,
2424 bool is_method, TRAPS) {
2425 // Nothing to do if loaders are the same.
2426 if (oopDesc::equals(loader1(), loader2())) {
2427 return NULL;
2428 }
2429
2430 SignatureStream sig_strm(signature, is_method);
2431 while (!sig_strm.is_done()) {
2432 if (sig_strm.is_object()) {
2433 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2434 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2435 return sig;
2436 }
2437 }
2438 sig_strm.next();
2439 }
2440 return NULL;
2441 }
2442
2443
2444 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2445 Symbol* signature,
2446 TRAPS) {
2447 methodHandle empty;
2448 assert(MethodHandles::is_signature_polymorphic(iid) &&
2449 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2450 iid != vmIntrinsics::_invokeGeneric,
2451 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2452
2453 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2454 int index = invoke_method_table()->hash_to_index(hash);
2455 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2456 methodHandle m;
2457 if (spe == NULL || spe->method() == NULL) {
2458 spe = NULL;
2459 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2460 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2461 if (!Arguments::is_interpreter_only()) {
2462 // Generate a compiled form of the MH intrinsic.
2463 AdapterHandlerLibrary::create_native_wrapper(m);
2464 // Check if have the compiled code.
2465 if (!m->has_compiled_code()) {
2466 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2467 "Out of space in CodeCache for method handle intrinsic", empty);
2468 }
2469 }
2470 // Now grab the lock. We might have to throw away the new method,
2471 // if a racing thread has managed to install one at the same time.
2472 {
2473 MutexLocker ml(SystemDictionary_lock, THREAD);
2474 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2475 if (spe == NULL)
2476 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2477 if (spe->method() == NULL)
2478 spe->set_method(m());
2479 }
2480 }
2481
2482 assert(spe != NULL && spe->method() != NULL, "");
2483 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2484 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2485 "MH intrinsic invariant");
2486 return spe->method();
2487 }
2488
2489 // Helper for unpacking the return value from linkMethod and linkCallSite.
2490 static methodHandle unpack_method_and_appendix(Handle mname,
2491 Klass* accessing_klass,
2492 objArrayHandle appendix_box,
2493 Handle* appendix_result,
2494 TRAPS) {
2495 methodHandle empty;
2496 if (mname.not_null()) {
2497 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2498 if (m != NULL) {
2499 oop appendix = appendix_box->obj_at(0);
2500 if (TraceMethodHandles) {
2501 #ifndef PRODUCT
2502 ttyLocker ttyl;
2503 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2504 m->print();
2505 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2506 tty->cr();
2507 #endif //PRODUCT
2508 }
2509 (*appendix_result) = Handle(THREAD, appendix);
2510 // the target is stored in the cpCache and if a reference to this
2511 // MemberName is dropped we need a way to make sure the
2512 // class_loader containing this method is kept alive.
2513 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2514 this_key->record_dependency(m->method_holder());
2515 return methodHandle(THREAD, m);
2516 }
2517 }
2518 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2519 return empty;
2520 }
2521
2522 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2523 Symbol* name,
2524 Symbol* signature,
2525 Klass* accessing_klass,
2526 Handle *appendix_result,
2527 Handle *method_type_result,
2528 TRAPS) {
2529 methodHandle empty;
2530 assert(THREAD->can_call_java() ,"");
2531 Handle method_type =
2532 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2533
2534 int ref_kind = JVM_REF_invokeVirtual;
2535 oop name_oop = StringTable::intern(name, CHECK_(empty));
2536 Handle name_str (THREAD, name_oop);
2537 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2538 assert(appendix_box->obj_at(0) == NULL, "");
2539
2540 // This should not happen. JDK code should take care of that.
2541 if (accessing_klass == NULL || method_type.is_null()) {
2542 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2543 }
2544
2545 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2546 JavaCallArguments args;
2547 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2548 args.push_int(ref_kind);
2549 args.push_oop(Handle(THREAD, klass->java_mirror()));
2550 args.push_oop(name_str);
2551 args.push_oop(method_type);
2552 args.push_oop(appendix_box);
2553 JavaValue result(T_OBJECT);
2554 JavaCalls::call_static(&result,
2555 SystemDictionary::MethodHandleNatives_klass(),
2556 vmSymbols::linkMethod_name(),
2557 vmSymbols::linkMethod_signature(),
2558 &args, CHECK_(empty));
2559 Handle mname(THREAD, (oop) result.get_jobject());
2560 (*method_type_result) = method_type;
2561 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2562 }
2563
2564 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2565 // We must ensure that all class loaders everywhere will reach this class, for any client.
2566 // This is a safe bet for public classes in java.lang, such as Object and String.
2567 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2568 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2569 static bool is_always_visible_class(oop mirror) {
2570 Klass* klass = java_lang_Class::as_Klass(mirror);
2571 if (klass->is_objArray_klass()) {
2572 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2573 }
2574 if (klass->is_typeArray_klass()) {
2575 return true; // primitive array
2576 }
2577 assert(klass->is_instance_klass(), "%s", klass->external_name());
2578 return klass->is_public() &&
2579 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2580 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2581 }
2582
2583
2584 // Return the Java mirror (java.lang.Class instance) for a single-character
2585 // descriptor. This result, when available, is the same as produced by the
2586 // heavier API point of the same name that takes a Symbol.
2587 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2588 return java_lang_Class::primitive_mirror(char2type(signature_char));
2589 }
2590
2591 // Find or construct the Java mirror (java.lang.Class instance) for a
2592 // for the given field type signature, as interpreted relative to the
2593 // given class loader. Handles primitives, void, references, arrays,
2594 // and all other reflectable types, except method types.
2595 // N.B. Code in reflection should use this entry point.
2596 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2597 Klass* accessing_klass,
2598 Handle class_loader,
2599 Handle protection_domain,
2600 SignatureStream::FailureMode failure_mode,
2601 TRAPS) {
2602 Handle empty;
2603
2604 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2605 "one or the other, or perhaps neither");
2606
2607 Symbol* type = signature;
2608
2609 // What we have here must be a valid field descriptor,
2610 // and all valid field descriptors are supported.
2611 // Produce the same java.lang.Class that reflection reports.
2612 if (type->utf8_length() == 1) {
2613
2614 // It's a primitive. (Void has a primitive mirror too.)
2615 char ch = type->char_at(0);
2616 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2617 return Handle(THREAD, find_java_mirror_for_type(ch));
2618
2619 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2620
2621 // It's a reference type.
2622 if (accessing_klass != NULL) {
2623 class_loader = Handle(THREAD, accessing_klass->class_loader());
2624 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2625 }
2626 Klass* constant_type_klass;
2627 if (failure_mode == SignatureStream::ReturnNull) {
2628 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2629 CHECK_(empty));
2630 } else {
2631 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2632 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2633 throw_error, CHECK_(empty));
2634 }
2635 if (constant_type_klass == NULL) {
2636 return Handle(); // report failure this way
2637 }
2638 Handle mirror(THREAD, constant_type_klass->java_mirror());
2639
2640 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2641 if (accessing_klass != NULL) {
2642 Klass* sel_klass = constant_type_klass;
2643 bool fold_type_to_class = true;
2644 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2645 fold_type_to_class, CHECK_(empty));
2646 }
2647
2648 return mirror;
2649
2650 }
2651
2652 // Fall through to an error.
2653 assert(false, "unsupported mirror syntax");
2654 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2655 }
2656
2657
2658 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2659 // signature, as interpreted relative to the given class loader.
2660 // Because of class loader constraints, all method handle usage must be
2661 // consistent with this loader.
2662 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2663 Klass* accessing_klass,
2664 TRAPS) {
2665 Handle empty;
2666 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2667 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2668 int index = invoke_method_table()->hash_to_index(hash);
2669 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2670 if (spe != NULL && spe->method_type() != NULL) {
2671 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2672 return Handle(THREAD, spe->method_type());
2673 } else if (!THREAD->can_call_java()) {
2674 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2675 return Handle(); // do not attempt from within compiler, unless it was cached
2676 }
2677
2678 Handle class_loader, protection_domain;
2679 if (accessing_klass != NULL) {
2680 class_loader = Handle(THREAD, accessing_klass->class_loader());
2681 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2682 }
2683 bool can_be_cached = true;
2684 int npts = ArgumentCount(signature).size();
2685 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2686 int arg = 0;
2687 Handle rt; // the return type from the signature
2688 ResourceMark rm(THREAD);
2689 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2690 oop mirror = NULL;
2691 if (can_be_cached) {
2692 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2693 mirror = ss.as_java_mirror(Handle(), Handle(),
2694 SignatureStream::ReturnNull, CHECK_(empty));
2695 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2696 // Fall back to accessing_klass context.
2697 can_be_cached = false;
2698 }
2699 }
2700 if (!can_be_cached) {
2701 // Resolve, throwing a real error if it doesn't work.
2702 mirror = ss.as_java_mirror(class_loader, protection_domain,
2703 SignatureStream::NCDFError, CHECK_(empty));
2704 }
2705 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2706 if (ss.at_return_type())
2707 rt = Handle(THREAD, mirror);
2708 else
2709 pts->obj_at_put(arg++, mirror);
2710
2711 // Check accessibility.
2712 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2713 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2714 mirror = NULL; // safety
2715 // Emulate ConstantPool::verify_constant_pool_resolve.
2716 bool fold_type_to_class = true;
2717 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2718 fold_type_to_class, CHECK_(empty));
2719 }
2720 }
2721 assert(arg == npts, "");
2722
2723 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2724 JavaCallArguments args(Handle(THREAD, rt()));
2725 args.push_oop(pts);
2726 JavaValue result(T_OBJECT);
2727 JavaCalls::call_static(&result,
2728 SystemDictionary::MethodHandleNatives_klass(),
2729 vmSymbols::findMethodHandleType_name(),
2730 vmSymbols::findMethodHandleType_signature(),
2731 &args, CHECK_(empty));
2732 Handle method_type(THREAD, (oop) result.get_jobject());
2733
2734 if (can_be_cached) {
2735 // We can cache this MethodType inside the JVM.
2736 MutexLocker ml(SystemDictionary_lock, THREAD);
2737 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2738 if (spe == NULL)
2739 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2740 if (spe->method_type() == NULL) {
2741 spe->set_method_type(method_type());
2742 }
2743 }
2744
2745 // report back to the caller with the MethodType
2746 return method_type;
2747 }
2748
2749 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2750 Klass* accessing_klass,
2751 TRAPS) {
2752 Handle empty;
2753 ResourceMark rm(THREAD);
2754 SignatureStream ss(signature, /*is_method=*/ false);
2755 if (!ss.is_done()) {
2756 Handle class_loader, protection_domain;
2757 if (accessing_klass != NULL) {
2758 class_loader = Handle(THREAD, accessing_klass->class_loader());
2759 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2760 }
2761 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2762 ss.next();
2763 if (ss.is_done()) {
2764 return Handle(THREAD, mirror);
2765 }
2766 }
2767 return empty;
2768 }
2769
2770 // Ask Java code to find or construct a method handle constant.
2771 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2772 int ref_kind, //e.g., JVM_REF_invokeVirtual
2773 Klass* callee,
2774 Symbol* name,
2775 Symbol* signature,
2776 TRAPS) {
2777 Handle empty;
2778 if (caller == NULL) {
2779 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2780 }
2781 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2782 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2783
2784 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2785 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2786 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2787 java_lang_invoke_MemberName::set_name (mname(), name_str());
2788 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2789 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2790
2791 if (ref_kind == JVM_REF_invokeVirtual &&
2792 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2793 // Skip resolution for public signature polymorphic methods such as
2794 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2795 // They require appendix argument which MemberName resolution doesn't handle.
2796 // There's special logic on JDK side to handle them
2797 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2798 } else {
2799 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2800 }
2801
2802 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2803 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2804
2805 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2806 JavaCallArguments args;
2807 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2808 args.push_int(ref_kind);
2809 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2810 args.push_oop(name_str);
2811 args.push_oop(type);
2812 JavaValue result(T_OBJECT);
2813 JavaCalls::call_static(&result,
2814 SystemDictionary::MethodHandleNatives_klass(),
2815 vmSymbols::linkMethodHandleConstant_name(),
2816 vmSymbols::linkMethodHandleConstant_signature(),
2817 &args, CHECK_(empty));
2818 return Handle(THREAD, (oop) result.get_jobject());
2819 }
2820
2821 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2822 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2823 int condy_index,
2824 Handle bootstrap_specifier,
2825 Symbol* name,
2826 Symbol* type,
2827 TRAPS) {
2828 Handle empty;
2829 Handle bsm, info;
2830 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2831 bsm = bootstrap_specifier;
2832 } else {
2833 assert(bootstrap_specifier->is_objArray(), "");
2834 objArrayOop args = (objArrayOop) bootstrap_specifier();
2835 assert(args->length() == 2, "");
2836 bsm = Handle(THREAD, args->obj_at(0));
2837 info = Handle(THREAD, args->obj_at(1));
2838 }
2839 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2840 "caller must supply a valid BSM");
2841
2842 // This should not happen. JDK code should take care of that.
2843 if (caller == NULL) {
2844 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2845 }
2846
2847 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2848
2849 // Resolve the constant type in the context of the caller class
2850 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2851 CHECK_(empty));
2852
2853 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2854 JavaCallArguments args;
2855 args.push_oop(Handle(THREAD, caller->java_mirror()));
2856 args.push_int(condy_index);
2857 args.push_oop(bsm);
2858 args.push_oop(constant_name);
2859 args.push_oop(type_mirror);
2860 args.push_oop(info);
2861 JavaValue result(T_OBJECT);
2862 JavaCalls::call_static(&result,
2863 SystemDictionary::MethodHandleNatives_klass(),
2864 vmSymbols::linkDynamicConstant_name(),
2865 vmSymbols::linkDynamicConstant_signature(),
2866 &args, CHECK_(empty));
2867
2868 return Handle(THREAD, (oop) result.get_jobject());
2869 }
2870
2871 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2872 // name and signature, as interpreted relative to the given class loader.
2873 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2874 int indy_index,
2875 Handle bootstrap_specifier,
2876 Symbol* name,
2877 Symbol* type,
2878 Handle *appendix_result,
2879 Handle *method_type_result,
2880 TRAPS) {
2881 methodHandle empty;
2882 Handle bsm, info;
2883 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2884 bsm = bootstrap_specifier;
2885 } else {
2886 objArrayOop args = (objArrayOop) bootstrap_specifier();
2887 assert(args->length() == 2, "");
2888 bsm = Handle(THREAD, args->obj_at(0));
2889 info = Handle(THREAD, args->obj_at(1));
2890 }
2891 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2892 "caller must supply a valid BSM");
2893
2894 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2895 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2896
2897 // This should not happen. JDK code should take care of that.
2898 if (caller == NULL || method_type.is_null()) {
2899 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2900 }
2901
2902 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2903 assert(appendix_box->obj_at(0) == NULL, "");
2904
2905 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2906 JavaCallArguments args;
2907 args.push_oop(Handle(THREAD, caller->java_mirror()));
2908 args.push_int(indy_index);
2909 args.push_oop(bsm);
2910 args.push_oop(method_name);
2911 args.push_oop(method_type);
2912 args.push_oop(info);
2913 args.push_oop(appendix_box);
2914 JavaValue result(T_OBJECT);
2915 JavaCalls::call_static(&result,
2916 SystemDictionary::MethodHandleNatives_klass(),
2917 vmSymbols::linkCallSite_name(),
2918 vmSymbols::linkCallSite_signature(),
2919 &args, CHECK_(empty));
2920 Handle mname(THREAD, (oop) result.get_jobject());
2921 (*method_type_result) = method_type;
2922 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2923 }
2924
2925 // Protection domain cache table handling
2926
2927 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2928 return _pd_cache_table->get(protection_domain);
2929 }
2930
2931 #if INCLUDE_CDS
2932 void SystemDictionary::reorder_dictionary_for_sharing() {
2933 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2934 }
2935 #endif
2936
2937 size_t SystemDictionary::count_bytes_for_buckets() {
2938 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2939 }
2940
2941 size_t SystemDictionary::count_bytes_for_table() {
2942 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2943 }
2944
2945 void SystemDictionary::copy_buckets(char* top, char* end) {
2946 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2947 }
2948
2949 void SystemDictionary::copy_table(char* top, char* end) {
2950 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2951 }
2952
2953 // ----------------------------------------------------------------------------
2954 void SystemDictionary::print_shared(outputStream *st) {
2955 shared_dictionary()->print_on(st);
2956 }
2957
2958 void SystemDictionary::print_on(outputStream *st) {
2959 if (shared_dictionary() != NULL) {
2960 st->print_cr("Shared Dictionary");
2961 shared_dictionary()->print_on(st);
2962 st->cr();
2963 }
2964
2965 GCMutexLocker mu(SystemDictionary_lock);
2966
2967 ClassLoaderDataGraph::print_dictionary(st);
2968
2969 // Placeholders
2970 placeholders()->print_on(st);
2971 st->cr();
2972
2973 // loader constraints - print under SD_lock
2974 constraints()->print_on(st);
2975 st->cr();
2976
2977 _pd_cache_table->print_on(st);
2978 st->cr();
2979 }
2980
2981 void SystemDictionary::verify() {
2982 guarantee(constraints() != NULL,
2983 "Verify of loader constraints failed");
2984 guarantee(placeholders()->number_of_entries() >= 0,
2985 "Verify of placeholders failed");
2986
2987 GCMutexLocker mu(SystemDictionary_lock);
2988
2989 // Verify dictionary
2990 ClassLoaderDataGraph::verify_dictionary();
2991
2992 placeholders()->verify();
2993
2994 // Verify constraint table
2995 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2996 constraints()->verify(placeholders());
2997
2998 _pd_cache_table->verify();
2999 }
3000
3001 void SystemDictionary::dump(outputStream *st, bool verbose) {
3002 assert_locked_or_safepoint(SystemDictionary_lock);
3003 if (verbose) {
3004 print_on(st);
3005 } else {
3006 if (shared_dictionary() != NULL) {
3007 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3008 }
3009 ClassLoaderDataGraph::print_dictionary_statistics(st);
3010 placeholders()->print_table_statistics(st, "Placeholder Table");
3011 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3012 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3013 }
3014 }
3015
3016 // Utility for dumping dictionaries.
3017 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3018 DCmdWithParser(output, heap),
3019 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3020 "BOOLEAN", false, "false") {
3021 _dcmdparser.add_dcmd_option(&_verbose);
3022 }
3023
3024 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3025 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3026 _verbose.value());
3027 VMThread::execute(&dumper);
3028 }
3029
3030 int SystemDictionaryDCmd::num_arguments() {
3031 ResourceMark rm;
3032 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3033 if (dcmd != NULL) {
3034 DCmdMark mark(dcmd);
3035 return dcmd->_dcmdparser.num_arguments();
3036 } else {
3037 return 0;
3038 }
3039 }
3040
3041 class CombineDictionariesClosure : public CLDClosure {
3042 private:
3043 Dictionary* _master_dictionary;
3044 public:
3045 CombineDictionariesClosure(Dictionary* master_dictionary) :
3046 _master_dictionary(master_dictionary) {}
3047 void do_cld(ClassLoaderData* cld) {
3048 ResourceMark rm;
3049 if (cld->is_unsafe_anonymous()) {
3050 return;
3051 }
3052 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3053 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3054 Dictionary* curr_dictionary = cld->dictionary();
3055 DictionaryEntry* p = curr_dictionary->bucket(i);
3056 while (p != NULL) {
3057 Symbol* name = p->instance_klass()->name();
3058 unsigned int d_hash = _master_dictionary->compute_hash(name);
3059 int d_index = _master_dictionary->hash_to_index(d_hash);
3060 DictionaryEntry* next = p->next();
3061 if (p->literal()->class_loader_data() != cld) {
3062 // This is an initiating class loader entry; don't use it
3063 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3064 curr_dictionary->free_entry(p);
3065 } else {
3066 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3067 curr_dictionary->unlink_entry(p);
3068 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3069 _master_dictionary->add_entry(d_index, p);
3070 }
3071 p = next;
3072 }
3073 *curr_dictionary->bucket_addr(i) = NULL;
3074 }
3075 }
3076 }
3077 };
3078
3079 // Combining platform and system loader dictionaries into boot loader dictionary.
3080 // During run time, we only have one shared dictionary.
3081 void SystemDictionary::combine_shared_dictionaries() {
3082 assert(DumpSharedSpaces, "dump time only");
3083 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3084 CombineDictionariesClosure cdc(master_dictionary);
3085 ClassLoaderDataGraph::cld_do(&cdc);
3086
3087 // These tables are no longer valid or necessary. Keeping them around will
3088 // cause SystemDictionary::verify() to fail. Let's empty them.
3089 _placeholders = new PlaceholderTable(_placeholder_table_size);
3090 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3091
3092 NOT_PRODUCT(SystemDictionary::verify());
3093 }
3094
3095 void SystemDictionary::initialize_oop_storage() {
3096 _vm_weak_oop_storage =
3097 new OopStorage("VM Weak Oop Handles",
3098 VMWeakAlloc_lock,
3099 VMWeakActive_lock);
3100 }
3101
3102 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3103 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3104 return _vm_weak_oop_storage;
3105 }