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 Lookup.defineClass nonfindable, unsafe_DefineAnonymousClass
991 // and redefineclasses. 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 const bool is_nonfindable,
999 const bool is_weaknonfindable,
1000 const bool can_access_vm_annotations,
1001 TRAPS) {
1002
1003 EventClassLoad class_load_start_event;
1004
1005 ClassLoaderData* loader_data;
1006
1007 if (unsafe_anonymous_host != NULL) {
1008 // - for unsafe anonymous class: create a new short-lived CLD that uses the same
1009 // class loader as the unsafe_anonymous_host.
1010 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1011 loader_data = ClassLoaderData::shortlived_class_loader_data(class_loader);
1012 } else if (is_nonfindable) {
1013 // - for weak nonfindable class: create a new short-lived CLD whose loader is
1014 // the Lookup class' loader.
1015 // - for nonfindable class: add the class to the Lookup class' loader's CLD.
1016 if (is_weaknonfindable) {
1017 loader_data = ClassLoaderData::shortlived_class_loader_data(class_loader);
1018 } else {
1019 // This nonfindable class goes into the regular CLD pool for this loader.
1020 loader_data = register_loader(class_loader);
1021 }
1022 } else {
1023 loader_data = ClassLoaderData::class_loader_data(class_loader());
1024 }
1025
1026 assert(st != NULL, "invariant");
1027 assert(st->need_verify(), "invariant");
1028
1029 // Parse stream and create a klass.
1030 // Note that we do this even though this klass might
1031 // already be present in the SystemDictionary, otherwise we would not
1032 // throw potential ClassFormatErrors.
1033
1034 InstanceKlass* k = KlassFactory::create_from_stream(st,
1035 class_name,
1036 loader_data,
1037 protection_domain,
1038 unsafe_anonymous_host,
1039 cp_patches,
1040 is_nonfindable,
1041 can_access_vm_annotations,
1042 CHECK_NULL);
1043
1044 if ((is_nonfindable || (unsafe_anonymous_host != NULL)) && k != NULL) {
1045 // Weak nonfindable and unsafe anonymous classes must update ClassLoaderData holder
1046 // so that they can be unloaded when the mirror is no longer referenced.
1047 if (is_weaknonfindable || (unsafe_anonymous_host != NULL)) {
1048 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1049 }
1050
1051 {
1052 MutexLocker mu_r(Compile_lock, THREAD);
1053
1054 // Add to class hierarchy, initialize vtables, and do possible
1055 // deoptimizations.
1056 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1057
1058 // But, do not add to dictionary.
1059
1060 // compiled code dependencies need to be validated anyway
1061 notice_modification();
1062 }
1063
1064 // Rewrite and patch constant pool here.
1065 k->link_class(CHECK_NULL);
1066 if (cp_patches != NULL) {
1067 k->constants()->patch_resolved_references(cp_patches);
1068 }
1069
1070 // Initialize it now, since nobody else will.
1071 k->eager_initialize(CHECK_NULL);
1072
1073 // notify jvmti
1074 if (JvmtiExport::should_post_class_load()) {
1075 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1076 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1077 }
1078 if (class_load_start_event.should_commit()) {
1079 post_class_load_event(&class_load_start_event, k, loader_data);
1080 }
1081 }
1082 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1083 "cp_patches only found with unsafe_anonymous_host");
1084
1085 return k;
1086 }
1087
1088 // Add a klass to the system from a stream (called by jni_DefineClass and
1089 // JVM_DefineClass).
1090 // Note: class_name can be NULL. In that case we do not know the name of
1091 // the class until we have parsed the stream.
1092
1093 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1094 Handle class_loader,
1095 Handle protection_domain,
1096 ClassFileStream* st,
1097 TRAPS) {
1098
1099 HandleMark hm(THREAD);
1100
1101 // Classloaders that support parallelism, e.g. bootstrap classloader,
1102 // do not acquire lock here
1103 bool DoObjectLock = true;
1104 if (is_parallelCapable(class_loader)) {
1105 DoObjectLock = false;
1106 }
1107
1108 ClassLoaderData* loader_data = register_loader(class_loader);
1109
1110 // Make sure we are synchronized on the class loader before we proceed
1111 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1112 check_loader_lock_contention(lockObject, THREAD);
1113 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1114
1115 assert(st != NULL, "invariant");
1116
1117 // Parse the stream and create a klass.
1118 // Note that we do this even though this klass might
1119 // already be present in the SystemDictionary, otherwise we would not
1120 // throw potential ClassFormatErrors.
1121 InstanceKlass* k = NULL;
1122
1123 #if INCLUDE_CDS
1124 if (!DumpSharedSpaces) {
1125 k = SystemDictionaryShared::lookup_from_stream(class_name,
1126 class_loader,
1127 protection_domain,
1128 st,
1129 CHECK_NULL);
1130 }
1131 #endif
1132
1133 if (k == NULL) {
1134 if (st->buffer() == NULL) {
1135 return NULL;
1136 }
1137 k = KlassFactory::create_from_stream(st,
1138 class_name,
1139 loader_data,
1140 protection_domain,
1141 NULL, // unsafe_anonymous_host
1142 NULL, // cp_patches
1143 false, // is_nonfindable
1144 false, // can_access_vm_annotations
1145 CHECK_NULL);
1146 }
1147
1148 assert(k != NULL, "no klass created");
1149 Symbol* h_name = k->name();
1150 assert(class_name == NULL || class_name == h_name, "name mismatch");
1151
1152 // Add class just loaded
1153 // If a class loader supports parallel classloading handle parallel define requests
1154 // find_or_define_instance_class may return a different InstanceKlass
1155 if (is_parallelCapable(class_loader)) {
1156 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1157 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1158 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1159 assert(defined_k != NULL, "Should have a klass if there's no exception");
1160 loader_data->add_to_deallocate_list(k);
1161 k = defined_k;
1162 }
1163 } else {
1164 define_instance_class(k, THREAD);
1165 }
1166
1167 // If defining the class throws an exception register 'k' for cleanup.
1168 if (HAS_PENDING_EXCEPTION) {
1169 assert(k != NULL, "Must have an instance klass here!");
1170 loader_data->add_to_deallocate_list(k);
1171 return NULL;
1172 }
1173
1174 // Make sure we have an entry in the SystemDictionary on success
1175 debug_only( {
1176 MutexLocker mu(SystemDictionary_lock, THREAD);
1177
1178 Klass* check = find_class(h_name, k->class_loader_data());
1179 assert(check == k, "should be present in the dictionary");
1180 } );
1181
1182 return k;
1183 }
1184
1185 #if INCLUDE_CDS
1186 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1187 int number_of_entries) {
1188 assert(!DumpSharedSpaces, "Should not be called with DumpSharedSpaces");
1189 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1190 "bad shared dictionary size.");
1191 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1192 _shared_dictionary_size, t, number_of_entries,
1193 false /* explicitly set _resizable to false */);
1194 }
1195
1196
1197 // If there is a shared dictionary, then find the entry for the
1198 // given shared system class, if any.
1199
1200 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1201 if (shared_dictionary() != NULL) {
1202 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1203 int d_index = shared_dictionary()->hash_to_index(d_hash);
1204
1205 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1206 } else {
1207 return NULL;
1208 }
1209 }
1210
1211
1212 // Load a class from the shared spaces (found through the shared system
1213 // dictionary). Force the superclass and all interfaces to be loaded.
1214 // Update the class definition to include sibling classes and no
1215 // subclasses (yet). [Classes in the shared space are not part of the
1216 // object hierarchy until loaded.]
1217
1218 InstanceKlass* SystemDictionary::load_shared_class(
1219 Symbol* class_name, Handle class_loader, TRAPS) {
1220 InstanceKlass* ik = find_shared_class(class_name);
1221 // Make sure we only return the boot class for the NULL classloader.
1222 if (ik != NULL &&
1223 ik->is_shared_boot_class() && class_loader.is_null()) {
1224 Handle protection_domain;
1225 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1226 }
1227 return NULL;
1228 }
1229
1230 // Check if a shared class can be loaded by the specific classloader:
1231 //
1232 // NULL classloader:
1233 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1234 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1235 // be defined in an unnamed module.
1236 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1237 InstanceKlass* ik,
1238 Handle class_loader, TRAPS) {
1239 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1240 "Cannot use sharing if java.base is patched");
1241 ResourceMark rm;
1242 int path_index = ik->shared_classpath_index();
1243 ClassLoaderData* loader_data = class_loader_data(class_loader);
1244 if (path_index < 0) {
1245 // path_index < 0 indicates that the class is intended for a custom loader
1246 // and should not be loaded by boot/platform/app loaders
1247 if (loader_data->is_builtin_class_loader_data()) {
1248 return false;
1249 } else {
1250 return true;
1251 }
1252 }
1253 SharedClassPathEntry* ent =
1254 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1255 if (!Universe::is_module_initialized()) {
1256 assert(ent != NULL && ent->is_modules_image(),
1257 "Loading non-bootstrap classes before the module system is initialized");
1258 assert(class_loader.is_null(), "sanity");
1259 return true;
1260 }
1261 // Get the pkg_entry from the classloader
1262 TempNewSymbol pkg_name = NULL;
1263 PackageEntry* pkg_entry = NULL;
1264 ModuleEntry* mod_entry = NULL;
1265 const char* pkg_string = NULL;
1266 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1267 if (pkg_name != NULL) {
1268 pkg_string = pkg_name->as_C_string();
1269 if (loader_data != NULL) {
1270 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1271 }
1272 if (pkg_entry != NULL) {
1273 mod_entry = pkg_entry->module();
1274 }
1275 }
1276
1277 // If the archived class is from a module that has been patched at runtime,
1278 // the class cannot be loaded from the archive.
1279 if (mod_entry != NULL && mod_entry->is_patched()) {
1280 return false;
1281 }
1282
1283 if (class_loader.is_null()) {
1284 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1285 // The NULL classloader can load archived class originated from the
1286 // "modules" jimage and the -Xbootclasspath/a. For class from the
1287 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1288 // by the NULL classloader.
1289 if (mod_entry != NULL) {
1290 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1291 // ModuleEntry's location agrees with the archived class' origination.
1292 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1293 return true; // Module class from the "module" jimage
1294 }
1295 }
1296
1297 // If the archived class is not from the "module" jimage, the class can be
1298 // loaded by the NULL classloader if
1299 //
1300 // 1. the class is from the unamed package
1301 // 2. or, the class is not from a module defined in the NULL classloader
1302 // 3. or, the class is from an unamed module
1303 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1304 // the class is from the -Xbootclasspath/a
1305 if (pkg_string == NULL ||
1306 pkg_entry == NULL ||
1307 pkg_entry->in_unnamed_module()) {
1308 assert(mod_entry == NULL ||
1309 mod_entry == loader_data->unnamed_module(),
1310 "the unnamed module is not defined in the classloader");
1311 return true;
1312 }
1313 }
1314 return false;
1315 } else {
1316 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1317 ik, class_loader, pkg_string, pkg_name,
1318 pkg_entry, mod_entry, CHECK_(false));
1319 return res;
1320 }
1321 }
1322
1323 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1324 Handle class_loader,
1325 Handle protection_domain, TRAPS) {
1326
1327 if (ik != NULL) {
1328 Symbol* class_name = ik->name();
1329
1330 bool visible = is_shared_class_visible(
1331 class_name, ik, class_loader, CHECK_NULL);
1332 if (!visible) {
1333 return NULL;
1334 }
1335
1336 // Resolve the superclass and interfaces. They must be the same
1337 // as in dump time, because the layout of <ik> depends on
1338 // the specific layout of ik->super() and ik->local_interfaces().
1339 //
1340 // If unexpected superclass or interfaces are found, we cannot
1341 // load <ik> from the shared archive.
1342
1343 if (ik->super() != NULL) {
1344 Symbol* cn = ik->super()->name();
1345 Klass *s = resolve_super_or_fail(class_name, cn,
1346 class_loader, protection_domain, true, CHECK_NULL);
1347 if (s != ik->super()) {
1348 // The dynamically resolved super class is not the same as the one we used during dump time,
1349 // so we cannot use ik.
1350 return NULL;
1351 } else {
1352 assert(s->is_shared(), "must be");
1353 }
1354 }
1355
1356 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1357 int num_interfaces = interfaces->length();
1358 for (int index = 0; index < num_interfaces; index++) {
1359 InstanceKlass* k = interfaces->at(index);
1360 Symbol* name = k->name();
1361 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1362 if (k != i) {
1363 // The dynamically resolved interface class is not the same as the one we used during dump time,
1364 // so we cannot use ik.
1365 return NULL;
1366 } else {
1367 assert(i->is_shared(), "must be");
1368 }
1369 }
1370
1371 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1372 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1373 if (new_ik != NULL) {
1374 // The class is changed by CFLH. Return the new class. The shared class is
1375 // not used.
1376 return new_ik;
1377 }
1378
1379 // Adjust methods to recover missing data. They need addresses for
1380 // interpreter entry points and their default native method address
1381 // must be reset.
1382
1383 // Updating methods must be done under a lock so multiple
1384 // threads don't update these in parallel
1385 //
1386 // Shared classes are all currently loaded by either the bootstrap or
1387 // internal parallel class loaders, so this will never cause a deadlock
1388 // on a custom class loader lock.
1389
1390 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1391 {
1392 HandleMark hm(THREAD);
1393 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1394 check_loader_lock_contention(lockObject, THREAD);
1395 ObjectLocker ol(lockObject, THREAD, true);
1396 // prohibited package check assumes all classes loaded from archive call
1397 // restore_unshareable_info which calls ik->set_package()
1398 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1399 }
1400
1401 ik->print_class_load_logging(loader_data, NULL, NULL);
1402
1403 // For boot loader, ensure that GetSystemPackage knows that a class in this
1404 // package was loaded.
1405 if (class_loader.is_null()) {
1406 int path_index = ik->shared_classpath_index();
1407 ResourceMark rm;
1408 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1409 }
1410
1411 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1412 // Only dump the classes that can be stored into CDS archive
1413 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1414 ResourceMark rm(THREAD);
1415 classlist_file->print_cr("%s", ik->name()->as_C_string());
1416 classlist_file->flush();
1417 }
1418 }
1419
1420 // notify a class loaded from shared object
1421 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1422
1423 ik->set_has_passed_fingerprint_check(false);
1424 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1425 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1426 uint64_t cds_fp = ik->get_stored_fingerprint();
1427 if (aot_fp != 0 && aot_fp == cds_fp) {
1428 // This class matches with a class saved in an AOT library
1429 ik->set_has_passed_fingerprint_check(true);
1430 } else {
1431 ResourceMark rm;
1432 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1433 }
1434 }
1435 }
1436 return ik;
1437 }
1438
1439 void SystemDictionary::clear_invoke_method_table() {
1440 SymbolPropertyEntry* spe = NULL;
1441 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1442 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1443 while (p != NULL) {
1444 spe = p;
1445 p = p->next();
1446 _invoke_method_table->free_entry(spe);
1447 }
1448 }
1449 }
1450 #endif // INCLUDE_CDS
1451
1452 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1453
1454 if (class_loader.is_null()) {
1455 ResourceMark rm;
1456 PackageEntry* pkg_entry = NULL;
1457 bool search_only_bootloader_append = false;
1458 ClassLoaderData *loader_data = class_loader_data(class_loader);
1459
1460 // Find the package in the boot loader's package entry table.
1461 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1462 if (pkg_name != NULL) {
1463 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1464 }
1465
1466 // Prior to attempting to load the class, enforce the boot loader's
1467 // visibility boundaries.
1468 if (!Universe::is_module_initialized()) {
1469 // During bootstrapping, prior to module initialization, any
1470 // class attempting to be loaded must be checked against the
1471 // java.base packages in the boot loader's PackageEntryTable.
1472 // No class outside of java.base is allowed to be loaded during
1473 // this bootstrapping window.
1474 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1475 // Class is either in the unnamed package or in
1476 // a named package within the unnamed module. Either
1477 // case is outside of java.base, do not attempt to
1478 // load the class post java.base definition. If
1479 // java.base has not been defined, let the class load
1480 // and its package will be checked later by
1481 // ModuleEntryTable::verify_javabase_packages.
1482 if (ModuleEntryTable::javabase_defined()) {
1483 return NULL;
1484 }
1485 } else {
1486 // Check that the class' package is defined within java.base.
1487 ModuleEntry* mod_entry = pkg_entry->module();
1488 Symbol* mod_entry_name = mod_entry->name();
1489 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1490 return NULL;
1491 }
1492 }
1493 } else {
1494 // After the module system has been initialized, check if the class'
1495 // package is in a module defined to the boot loader.
1496 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1497 // Class is either in the unnamed package, in a named package
1498 // within a module not defined to the boot loader or in a
1499 // a named package within the unnamed module. In all cases,
1500 // limit visibility to search for the class only in the boot
1501 // loader's append path.
1502 search_only_bootloader_append = true;
1503 }
1504 }
1505
1506 // Prior to bootstrapping's module initialization, never load a class outside
1507 // of the boot loader's module path
1508 assert(Universe::is_module_initialized() ||
1509 !search_only_bootloader_append,
1510 "Attempt to load a class outside of boot loader's module path");
1511
1512 // Search the shared system dictionary for classes preloaded into the
1513 // shared spaces.
1514 InstanceKlass* k = NULL;
1515 {
1516 #if INCLUDE_CDS
1517 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1518 k = load_shared_class(class_name, class_loader, THREAD);
1519 #endif
1520 }
1521
1522 if (k == NULL) {
1523 // Use VM class loader
1524 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1525 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1526 }
1527
1528 // find_or_define_instance_class may return a different InstanceKlass
1529 if (k != NULL) {
1530 InstanceKlass* defined_k =
1531 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1532 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1533 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1534 assert(defined_k != NULL, "Should have a klass if there's no exception");
1535 loader_data->add_to_deallocate_list(k);
1536 k = defined_k;
1537 } else if (HAS_PENDING_EXCEPTION) {
1538 loader_data->add_to_deallocate_list(k);
1539 return NULL;
1540 }
1541 }
1542 return k;
1543 } else {
1544 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1545 ResourceMark rm(THREAD);
1546
1547 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1548 JavaThread* jt = (JavaThread*) THREAD;
1549
1550 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1551 ClassLoader::perf_app_classload_selftime(),
1552 ClassLoader::perf_app_classload_count(),
1553 jt->get_thread_stat()->perf_recursion_counts_addr(),
1554 jt->get_thread_stat()->perf_timers_addr(),
1555 PerfClassTraceTime::CLASS_LOAD);
1556
1557 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1558 // Translate to external class name format, i.e., convert '/' chars to '.'
1559 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1560
1561 JavaValue result(T_OBJECT);
1562
1563 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1564
1565 // Call public unsynchronized loadClass(String) directly for all class loaders.
1566 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1567 // acquire a class-name based lock rather than the class loader object lock.
1568 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1569 JavaCalls::call_virtual(&result,
1570 class_loader,
1571 spec_klass,
1572 vmSymbols::loadClass_name(),
1573 vmSymbols::string_class_signature(),
1574 string,
1575 CHECK_NULL);
1576
1577 assert(result.get_type() == T_OBJECT, "just checking");
1578 oop obj = (oop) result.get_jobject();
1579
1580 // Primitive classes return null since forName() can not be
1581 // used to obtain any of the Class objects representing primitives or void
1582 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1583 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1584 // For user defined Java class loaders, check that the name returned is
1585 // the same as that requested. This check is done for the bootstrap
1586 // loader when parsing the class file.
1587 if (class_name == k->name()) {
1588 return k;
1589 }
1590 }
1591 // Class is not found or has the wrong name, return NULL
1592 return NULL;
1593 }
1594 }
1595
1596 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1597 EventClassDefine event;
1598 if (event.should_commit()) {
1599 event.set_definedClass(k);
1600 event.set_definingClassLoader(def_cld);
1601 event.commit();
1602 }
1603 }
1604
1605 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1606
1607 HandleMark hm(THREAD);
1608 ClassLoaderData* loader_data = k->class_loader_data();
1609 Handle class_loader_h(THREAD, loader_data->class_loader());
1610
1611 // for bootstrap and other parallel classloaders don't acquire lock,
1612 // use placeholder token
1613 // If a parallelCapable class loader calls define_instance_class instead of
1614 // find_or_define_instance_class to get here, we have a timing
1615 // hole with systemDictionary updates and check_constraints
1616 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1617 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1618 compute_loader_lock_object(class_loader_h, THREAD)),
1619 "define called without lock");
1620 }
1621
1622 // Check class-loading constraints. Throw exception if violation is detected.
1623 // Grabs and releases SystemDictionary_lock
1624 // The check_constraints/find_class call and update_dictionary sequence
1625 // must be "atomic" for a specific class/classloader pair so we never
1626 // define two different instanceKlasses for that class/classloader pair.
1627 // Existing classloaders will call define_instance_class with the
1628 // classloader lock held
1629 // Parallel classloaders will call find_or_define_instance_class
1630 // which will require a token to perform the define class
1631 Symbol* name_h = k->name();
1632 Dictionary* dictionary = loader_data->dictionary();
1633 unsigned int d_hash = dictionary->compute_hash(name_h);
1634 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1635
1636 // Register class just loaded with class loader (placed in Vector)
1637 // Note we do this before updating the dictionary, as this can
1638 // fail with an OutOfMemoryError (if it does, we will *not* put this
1639 // class in the dictionary and will not update the class hierarchy).
1640 // JVMTI FollowReferences needs to find the classes this way.
1641 if (k->class_loader() != NULL) {
1642 methodHandle m(THREAD, Universe::loader_addClass_method());
1643 JavaValue result(T_VOID);
1644 JavaCallArguments args(class_loader_h);
1645 args.push_oop(Handle(THREAD, k->java_mirror()));
1646 JavaCalls::call(&result, m, &args, CHECK);
1647 }
1648
1649 // Add the new class. We need recompile lock during update of CHA.
1650 {
1651 unsigned int p_hash = placeholders()->compute_hash(name_h);
1652 int p_index = placeholders()->hash_to_index(p_hash);
1653
1654 MutexLocker mu_r(Compile_lock, THREAD);
1655
1656 // Add to class hierarchy, initialize vtables, and do possible
1657 // deoptimizations.
1658 add_to_hierarchy(k, CHECK); // No exception, but can block
1659
1660 // Add to systemDictionary - so other classes can see it.
1661 // Grabs and releases SystemDictionary_lock
1662 update_dictionary(d_hash, p_index, p_hash,
1663 k, class_loader_h, THREAD);
1664 }
1665 k->eager_initialize(THREAD);
1666
1667 // notify jvmti
1668 if (JvmtiExport::should_post_class_load()) {
1669 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1670 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1671
1672 }
1673 post_class_define_event(k, loader_data);
1674 }
1675
1676 // Support parallel classloading
1677 // All parallel class loaders, including bootstrap classloader
1678 // lock a placeholder entry for this class/class_loader pair
1679 // to allow parallel defines of different classes for this class loader
1680 // With AllowParallelDefine flag==true, in case they do not synchronize around
1681 // FindLoadedClass/DefineClass, calls, we check for parallel
1682 // loading for them, wait if a defineClass is in progress
1683 // and return the initial requestor's results
1684 // This flag does not apply to the bootstrap classloader.
1685 // With AllowParallelDefine flag==false, call through to define_instance_class
1686 // which will throw LinkageError: duplicate class definition.
1687 // False is the requested default.
1688 // For better performance, the class loaders should synchronize
1689 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1690 // potentially waste time reading and parsing the bytestream.
1691 // Note: VM callers should ensure consistency of k/class_name,class_loader
1692 // Be careful when modifying this code: once you have run
1693 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1694 // you need to find_and_remove it before returning.
1695 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1696 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1697 InstanceKlass* k, TRAPS) {
1698
1699 Symbol* name_h = k->name(); // passed in class_name may be null
1700 ClassLoaderData* loader_data = class_loader_data(class_loader);
1701 Dictionary* dictionary = loader_data->dictionary();
1702
1703 unsigned int d_hash = dictionary->compute_hash(name_h);
1704
1705 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1706 unsigned int p_hash = placeholders()->compute_hash(name_h);
1707 int p_index = placeholders()->hash_to_index(p_hash);
1708 PlaceholderEntry* probe;
1709
1710 {
1711 MutexLocker mu(SystemDictionary_lock, THREAD);
1712 // First check if class already defined
1713 if (is_parallelDefine(class_loader)) {
1714 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1715 if (check != NULL) {
1716 return check;
1717 }
1718 }
1719
1720 // Acquire define token for this class/classloader
1721 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1722 // Wait if another thread defining in parallel
1723 // All threads wait - even those that will throw duplicate class: otherwise
1724 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1725 // if other thread has not finished updating dictionary
1726 while (probe->definer() != NULL) {
1727 SystemDictionary_lock->wait();
1728 }
1729 // Only special cases allow parallel defines and can use other thread's results
1730 // Other cases fall through, and may run into duplicate defines
1731 // caught by finding an entry in the SystemDictionary
1732 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1733 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1734 SystemDictionary_lock->notify_all();
1735 #ifdef ASSERT
1736 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1737 assert(check != NULL, "definer missed recording success");
1738 #endif
1739 return probe->instance_klass();
1740 } else {
1741 // This thread will define the class (even if earlier thread tried and had an error)
1742 probe->set_definer(THREAD);
1743 }
1744 }
1745
1746 define_instance_class(k, THREAD);
1747
1748 Handle linkage_exception = Handle(); // null handle
1749
1750 // definer must notify any waiting threads
1751 {
1752 MutexLocker mu(SystemDictionary_lock, THREAD);
1753 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1754 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1755 if (probe != NULL) {
1756 if (HAS_PENDING_EXCEPTION) {
1757 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1758 CLEAR_PENDING_EXCEPTION;
1759 } else {
1760 probe->set_instance_klass(k);
1761 }
1762 probe->set_definer(NULL);
1763 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1764 SystemDictionary_lock->notify_all();
1765 }
1766 }
1767
1768 // Can't throw exception while holding lock due to rank ordering
1769 if (linkage_exception() != NULL) {
1770 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1771 }
1772
1773 return k;
1774 }
1775
1776 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1777 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1778 if (class_loader.is_null()) {
1779 return Handle(THREAD, _system_loader_lock_obj);
1780 } else {
1781 return class_loader;
1782 }
1783 }
1784
1785 // This method is added to check how often we have to wait to grab loader
1786 // lock. The results are being recorded in the performance counters defined in
1787 // ClassLoader::_sync_systemLoaderLockContentionRate and
1788 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1789 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1790 if (!UsePerfData) {
1791 return;
1792 }
1793
1794 assert(!loader_lock.is_null(), "NULL lock object");
1795
1796 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1797 == ObjectSynchronizer::owner_other) {
1798 // contention will likely happen, so increment the corresponding
1799 // contention counter.
1800 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1801 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1802 } else {
1803 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1804 }
1805 }
1806 }
1807
1808 // ----------------------------------------------------------------------------
1809 // Lookup
1810
1811 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1812 Symbol* class_name,
1813 Dictionary* dictionary) {
1814 assert_locked_or_safepoint(SystemDictionary_lock);
1815 int index = dictionary->hash_to_index(hash);
1816 return dictionary->find_class(index, hash, class_name);
1817 }
1818
1819
1820 // Basic find on classes in the midst of being loaded
1821 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1822 ClassLoaderData* loader_data) {
1823 assert_locked_or_safepoint(SystemDictionary_lock);
1824 unsigned int p_hash = placeholders()->compute_hash(class_name);
1825 int p_index = placeholders()->hash_to_index(p_hash);
1826 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1827 }
1828
1829
1830 // Used for assertions and verification only
1831 // Precalculating the hash and index is an optimization because there are many lookups
1832 // before adding the class.
1833 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1834 assert_locked_or_safepoint(SystemDictionary_lock);
1835 #ifndef ASSERT
1836 guarantee(VerifyBeforeGC ||
1837 VerifyDuringGC ||
1838 VerifyBeforeExit ||
1839 VerifyDuringStartup ||
1840 VerifyAfterGC, "too expensive");
1841 #endif
1842
1843 Dictionary* dictionary = loader_data->dictionary();
1844 unsigned int d_hash = dictionary->compute_hash(class_name);
1845 return find_class(d_hash, class_name, dictionary);
1846 }
1847
1848
1849 // ----------------------------------------------------------------------------
1850 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1851 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1852 // before a new class is used.
1853
1854 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1855 assert(k != NULL, "just checking");
1856 assert_locked_or_safepoint(Compile_lock);
1857
1858 // Link into hierachy. Make sure the vtables are initialized before linking into
1859 k->append_to_sibling_list(); // add to superklass/sibling list
1860 k->process_interfaces(THREAD); // handle all "implements" declarations
1861 k->set_init_state(InstanceKlass::loaded);
1862 // Now flush all code that depended on old class hierarchy.
1863 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1864 // Also, first reinitialize vtable because it may have gotten out of synch
1865 // while the new class wasn't connected to the class hierarchy.
1866 CodeCache::flush_dependents_on(k);
1867 }
1868
1869 // ----------------------------------------------------------------------------
1870 // GC support
1871
1872 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1873 // Note: anonymous classes are not in the SD.
1874 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1875 bool do_cleaning) {
1876
1877 bool unloading_occurred;
1878 {
1879 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1880
1881 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1882 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1883 if (unloading_occurred) {
1884 JFR_ONLY(Jfr::on_unloading_classes();)
1885 ClassLoaderDataGraph::clean_module_and_package_info();
1886 }
1887 }
1888
1889 // TODO: just return if !unloading_occurred.
1890 if (unloading_occurred) {
1891 {
1892 GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
1893 // Check if there's work to do in the SymbolTable
1894 SymbolTable::do_check_concurrent_work();
1895 }
1896
1897 {
1898 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1899 constraints()->purge_loader_constraints();
1900 resolution_errors()->purge_resolution_errors();
1901 }
1902 }
1903
1904 {
1905 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1906 // Oops referenced by the protection domain cache table may get unreachable independently
1907 // of the class loader (eg. cached protection domain oops). So we need to
1908 // explicitly unlink them here.
1909 _pd_cache_table->trigger_cleanup();
1910 }
1911
1912 if (do_cleaning) {
1913 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1914 ResolvedMethodTable::trigger_cleanup();
1915 }
1916
1917 return unloading_occurred;
1918 }
1919
1920 void SystemDictionary::oops_do(OopClosure* f) {
1921 f->do_oop(&_java_system_loader);
1922 f->do_oop(&_java_platform_loader);
1923 f->do_oop(&_system_loader_lock_obj);
1924 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1925
1926 // Visit extra methods
1927 invoke_method_table()->oops_do(f);
1928 }
1929
1930 // CDS: scan and relocate all classes in the system dictionary.
1931 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1932 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1933 }
1934
1935 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1936 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1937 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1938 it->push(well_known_klass_addr((WKID)id));
1939 }
1940 }
1941
1942 void SystemDictionary::methods_do(void f(Method*)) {
1943 // Walk methods in loaded classes
1944 MutexLocker ml(ClassLoaderDataGraph_lock);
1945 ClassLoaderDataGraph::methods_do(f);
1946 // Walk method handle intrinsics
1947 invoke_method_table()->methods_do(f);
1948 }
1949
1950 class RemoveClassesClosure : public CLDClosure {
1951 public:
1952 void do_cld(ClassLoaderData* cld) {
1953 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1954 cld->dictionary()->remove_classes_in_error_state();
1955 }
1956 }
1957 };
1958
1959 void SystemDictionary::remove_classes_in_error_state() {
1960 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1961 RemoveClassesClosure rcc;
1962 MutexLocker ml(ClassLoaderDataGraph_lock);
1963 ClassLoaderDataGraph::cld_do(&rcc);
1964 }
1965
1966 // ----------------------------------------------------------------------------
1967 // Initialization
1968
1969 void SystemDictionary::initialize(TRAPS) {
1970 // Allocate arrays
1971 _placeholders = new PlaceholderTable(_placeholder_table_size);
1972 _number_of_modifications = 0;
1973 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1974 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1975 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1976 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1977
1978 // Allocate private object used as system class loader lock
1979 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1980 // Initialize basic classes
1981 resolve_preloaded_classes(CHECK);
1982 }
1983
1984 // Compact table of directions on the initialization of klasses:
1985 static const short wk_init_info[] = {
1986 #define WK_KLASS_INIT_INFO(name, symbol) \
1987 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1988
1989 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1990 #undef WK_KLASS_INIT_INFO
1991 0
1992 };
1993
1994 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1995 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1996 int sid = wk_init_info[id - FIRST_WKID];
1997 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1998 InstanceKlass** klassp = &_well_known_klasses[id];
1999
2000
2001 #if INCLUDE_JVMCI
2002 if (id >= FIRST_JVMCI_WKID) {
2003 assert(EnableJVMCI, "resolve JVMCI classes only when EnableJVMCI is true");
2004 }
2005 #endif
2006
2007 if ((*klassp) == NULL) {
2008 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
2009 (*klassp) = InstanceKlass::cast(k);
2010 }
2011 return ((*klassp) != NULL);
2012 }
2013
2014 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2015 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2016 for (int id = (int)start_id; id < (int)limit_id; id++) {
2017 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2018 resolve_wk_klass((WKID)id, CHECK);
2019 }
2020
2021 // move the starting value forward to the limit:
2022 start_id = limit_id;
2023 }
2024
2025 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
2026 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2027
2028 // Create the ModuleEntry for java.base. This call needs to be done here,
2029 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2030 ClassLoader::classLoader_init2(CHECK);
2031
2032 // Preload commonly used klasses
2033 WKID scan = FIRST_WKID;
2034 // first do Object, then String, Class
2035 #if INCLUDE_CDS
2036 if (UseSharedSpaces) {
2037 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2038
2039 // It's unsafe to access the archived heap regions before they
2040 // are fixed up, so we must do the fixup as early as possible
2041 // before the archived java objects are accessed by functions
2042 // such as java_lang_Class::restore_archived_mirror and
2043 // ConstantPool::restore_unshareable_info (restores the archived
2044 // resolved_references array object).
2045 //
2046 // HeapShared::fixup_mapped_heap_regions() fills the empty
2047 // spaces in the archived heap regions and may use
2048 // SystemDictionary::Object_klass(), so we can do this only after
2049 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2050 // call. No mirror objects are accessed/restored in the above call.
2051 // Mirrors are restored after java.lang.Class is loaded.
2052 HeapShared::fixup_mapped_heap_regions();
2053
2054 // Initialize the constant pool for the Object_class
2055 Object_klass()->constants()->restore_unshareable_info(CHECK);
2056 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2057 } else
2058 #endif
2059 {
2060 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2061 }
2062
2063 // Calculate offsets for String and Class classes since they are loaded and
2064 // can be used after this point.
2065 java_lang_String::compute_offsets();
2066 java_lang_Class::compute_offsets();
2067
2068 // Fixup mirrors for classes loaded before java.lang.Class.
2069 // These calls iterate over the objects currently in the perm gen
2070 // so calling them at this point is matters (not before when there
2071 // are fewer objects and not later after there are more objects
2072 // in the perm gen.
2073 Universe::initialize_basic_type_mirrors(CHECK);
2074 Universe::fixup_mirrors(CHECK);
2075
2076 // do a bunch more:
2077 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2078
2079 // Preload ref klasses and set reference types
2080 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2081 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2082
2083 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2084 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2085 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2086 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2087 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2088
2089 // JSR 292 classes
2090 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2091 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2092 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2093 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2094 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2095
2096 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2097 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2098 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2099 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2100 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2101 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2102 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2103 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2104 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2105 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2106
2107 { // Compute whether we should use checkPackageAccess or NOT
2108 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2109 _has_checkPackageAccess = (method != NULL);
2110 }
2111 }
2112
2113 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2114 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2115 BasicType SystemDictionary::box_klass_type(Klass* k) {
2116 assert(k != NULL, "");
2117 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2118 if (_box_klasses[i] == k)
2119 return (BasicType)i;
2120 }
2121 return T_OBJECT;
2122 }
2123
2124 // Constraints on class loaders. The details of the algorithm can be
2125 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2126 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2127 // that the dictionary needs to maintain a set of contraints that
2128 // must be satisfied by all classes in the dictionary.
2129 // if defining is true, then LinkageError if already in dictionary
2130 // if initiating loader, then ok if InstanceKlass matches existing entry
2131
2132 void SystemDictionary::check_constraints(unsigned int d_hash,
2133 InstanceKlass* k,
2134 Handle class_loader,
2135 bool defining,
2136 TRAPS) {
2137 ResourceMark rm(THREAD);
2138 stringStream ss;
2139 bool throwException = false;
2140
2141 {
2142 Symbol *name = k->name();
2143 ClassLoaderData *loader_data = class_loader_data(class_loader);
2144
2145 MutexLocker mu(SystemDictionary_lock, THREAD);
2146
2147 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2148 if (check != NULL) {
2149 // If different InstanceKlass - duplicate class definition,
2150 // else - ok, class loaded by a different thread in parallel.
2151 // We should only have found it if it was done loading and ok to use.
2152 // The dictionary only holds instance classes, placeholders
2153 // also hold array classes.
2154
2155 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2156 if ((defining == true) || (k != check)) {
2157 throwException = true;
2158 ss.print("loader %s", loader_data->loader_name_and_id());
2159 ss.print(" attempted duplicate %s definition for %s. (%s)",
2160 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2161 } else {
2162 return;
2163 }
2164 }
2165
2166 #ifdef ASSERT
2167 Symbol* ph_check = find_placeholder(name, loader_data);
2168 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2169 #endif
2170
2171 if (throwException == false) {
2172 if (constraints()->check_or_update(k, class_loader, name) == false) {
2173 throwException = true;
2174 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2175 ss.print(" wants to load %s %s.",
2176 k->external_kind(), k->external_name());
2177 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2178 if (existing_klass->class_loader() != class_loader()) {
2179 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2180 existing_klass->external_kind(),
2181 existing_klass->class_loader_data()->loader_name_and_id(),
2182 existing_klass->class_in_module_of_loader(false, true));
2183 } else {
2184 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2185 }
2186 }
2187 }
2188 }
2189
2190 // Throw error now if needed (cannot throw while holding
2191 // SystemDictionary_lock because of rank ordering)
2192 if (throwException == true) {
2193 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2194 }
2195 }
2196
2197 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2198 // have been called.
2199 void SystemDictionary::update_dictionary(unsigned int d_hash,
2200 int p_index, unsigned int p_hash,
2201 InstanceKlass* k,
2202 Handle class_loader,
2203 TRAPS) {
2204 // Compile_lock prevents systemDictionary updates during compilations
2205 assert_locked_or_safepoint(Compile_lock);
2206 Symbol* name = k->name();
2207 ClassLoaderData *loader_data = class_loader_data(class_loader);
2208
2209 {
2210 MutexLocker mu1(SystemDictionary_lock, THREAD);
2211
2212 // See whether biased locking is enabled and if so set it for this
2213 // klass.
2214 // Note that this must be done past the last potential blocking
2215 // point / safepoint. We enable biased locking lazily using a
2216 // VM_Operation to iterate the SystemDictionary and installing the
2217 // biasable mark word into each InstanceKlass's prototype header.
2218 // To avoid race conditions where we accidentally miss enabling the
2219 // optimization for one class in the process of being added to the
2220 // dictionary, we must not safepoint after the test of
2221 // BiasedLocking::enabled().
2222 if (UseBiasedLocking && BiasedLocking::enabled()) {
2223 // Set biased locking bit for all loaded classes; it will be
2224 // cleared if revocation occurs too often for this type
2225 // NOTE that we must only do this when the class is initally
2226 // defined, not each time it is referenced from a new class loader
2227 if (oopDesc::equals(k->class_loader(), class_loader())) {
2228 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2229 }
2230 }
2231
2232 // Make a new dictionary entry.
2233 Dictionary* dictionary = loader_data->dictionary();
2234 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2235 if (sd_check == NULL) {
2236 dictionary->add_klass(d_hash, name, k);
2237 notice_modification();
2238 }
2239 #ifdef ASSERT
2240 sd_check = find_class(d_hash, name, dictionary);
2241 assert (sd_check != NULL, "should have entry in dictionary");
2242 // Note: there may be a placeholder entry: for circularity testing
2243 // or for parallel defines
2244 #endif
2245 SystemDictionary_lock->notify_all();
2246 }
2247 }
2248
2249
2250 // Try to find a class name using the loader constraints. The
2251 // loader constraints might know about a class that isn't fully loaded
2252 // yet and these will be ignored.
2253 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2254 Symbol* class_name, Handle class_loader, TRAPS) {
2255
2256 // First see if it has been loaded directly.
2257 // Force the protection domain to be null. (This removes protection checks.)
2258 Handle no_protection_domain;
2259 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2260 no_protection_domain, CHECK_NULL);
2261 if (klass != NULL)
2262 return klass;
2263
2264 // Now look to see if it has been loaded elsewhere, and is subject to
2265 // a loader constraint that would require this loader to return the
2266 // klass that is already loaded.
2267 if (FieldType::is_array(class_name)) {
2268 // For array classes, their Klass*s are not kept in the
2269 // constraint table. The element Klass*s are.
2270 FieldArrayInfo fd;
2271 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2272 if (t != T_OBJECT) {
2273 klass = Universe::typeArrayKlassObj(t);
2274 } else {
2275 MutexLocker mu(SystemDictionary_lock, THREAD);
2276 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2277 }
2278 // If element class already loaded, allocate array klass
2279 if (klass != NULL) {
2280 klass = klass->array_klass_or_null(fd.dimension());
2281 }
2282 } else {
2283 MutexLocker mu(SystemDictionary_lock, THREAD);
2284 // Non-array classes are easy: simply check the constraint table.
2285 klass = constraints()->find_constrained_klass(class_name, class_loader);
2286 }
2287
2288 return klass;
2289 }
2290
2291
2292 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2293 Handle class_loader1,
2294 Handle class_loader2,
2295 Thread* THREAD) {
2296 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2297 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2298
2299 Symbol* constraint_name = NULL;
2300 // Needs to be in same scope as constraint_name in case a Symbol is created and
2301 // assigned to constraint_name.
2302 FieldArrayInfo fd;
2303 if (!FieldType::is_array(class_name)) {
2304 constraint_name = class_name;
2305 } else {
2306 // For array classes, their Klass*s are not kept in the
2307 // constraint table. The element classes are.
2308 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2309 // primitive types always pass
2310 if (t != T_OBJECT) {
2311 return true;
2312 } else {
2313 constraint_name = fd.object_key();
2314 }
2315 }
2316
2317 Dictionary* dictionary1 = loader_data1->dictionary();
2318 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2319
2320 Dictionary* dictionary2 = loader_data2->dictionary();
2321 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2322
2323 {
2324 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2325 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2326 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2327 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2328 klass2, class_loader2);
2329 }
2330 }
2331
2332 // Add entry to resolution error table to record the error when the first
2333 // attempt to resolve a reference to a class has failed.
2334 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2335 Symbol* error, Symbol* message) {
2336 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2337 int index = resolution_errors()->hash_to_index(hash);
2338 {
2339 MutexLocker ml(SystemDictionary_lock, Thread::current());
2340 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2341 }
2342 }
2343
2344 // Delete a resolution error for RedefineClasses for a constant pool is going away
2345 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2346 resolution_errors()->delete_entry(pool);
2347 }
2348
2349 // Lookup resolution error table. Returns error if found, otherwise NULL.
2350 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2351 Symbol** message) {
2352 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2353 int index = resolution_errors()->hash_to_index(hash);
2354 {
2355 MutexLocker ml(SystemDictionary_lock, Thread::current());
2356 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2357 if (entry != NULL) {
2358 *message = entry->message();
2359 return entry->error();
2360 } else {
2361 return NULL;
2362 }
2363 }
2364 }
2365
2366
2367 // Signature constraints ensure that callers and callees agree about
2368 // the meaning of type names in their signatures. This routine is the
2369 // intake for constraints. It collects them from several places:
2370 //
2371 // * LinkResolver::resolve_method (if check_access is true) requires
2372 // that the resolving class (the caller) and the defining class of
2373 // the resolved method (the callee) agree on each type in the
2374 // method's signature.
2375 //
2376 // * LinkResolver::resolve_interface_method performs exactly the same
2377 // checks.
2378 //
2379 // * LinkResolver::resolve_field requires that the constant pool
2380 // attempting to link to a field agree with the field's defining
2381 // class about the type of the field signature.
2382 //
2383 // * klassVtable::initialize_vtable requires that, when a class
2384 // overrides a vtable entry allocated by a superclass, that the
2385 // overriding method (i.e., the callee) agree with the superclass
2386 // on each type in the method's signature.
2387 //
2388 // * klassItable::initialize_itable requires that, when a class fills
2389 // in its itables, for each non-abstract method installed in an
2390 // itable, the method (i.e., the callee) agree with the interface
2391 // on each type in the method's signature.
2392 //
2393 // All those methods have a boolean (check_access, checkconstraints)
2394 // which turns off the checks. This is used from specialized contexts
2395 // such as bootstrapping, dumping, and debugging.
2396 //
2397 // No direct constraint is placed between the class and its
2398 // supertypes. Constraints are only placed along linked relations
2399 // between callers and callees. When a method overrides or implements
2400 // an abstract method in a supertype (superclass or interface), the
2401 // constraints are placed as if the supertype were the caller to the
2402 // overriding method. (This works well, since callers to the
2403 // supertype have already established agreement between themselves and
2404 // the supertype.) As a result of all this, a class can disagree with
2405 // its supertype about the meaning of a type name, as long as that
2406 // class neither calls a relevant method of the supertype, nor is
2407 // called (perhaps via an override) from the supertype.
2408 //
2409 //
2410 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2411 //
2412 // Make sure all class components (including arrays) in the given
2413 // signature will be resolved to the same class in both loaders.
2414 // Returns the name of the type that failed a loader constraint check, or
2415 // NULL if no constraint failed. No exception except OOME is thrown.
2416 // Arrays are not added to the loader constraint table, their elements are.
2417 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2418 Handle loader1, Handle loader2,
2419 bool is_method, TRAPS) {
2420 // Nothing to do if loaders are the same.
2421 if (oopDesc::equals(loader1(), loader2())) {
2422 return NULL;
2423 }
2424
2425 SignatureStream sig_strm(signature, is_method);
2426 while (!sig_strm.is_done()) {
2427 if (sig_strm.is_object()) {
2428 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2429 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2430 return sig;
2431 }
2432 }
2433 sig_strm.next();
2434 }
2435 return NULL;
2436 }
2437
2438
2439 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2440 Symbol* signature,
2441 TRAPS) {
2442 methodHandle empty;
2443 assert(MethodHandles::is_signature_polymorphic(iid) &&
2444 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2445 iid != vmIntrinsics::_invokeGeneric,
2446 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2447
2448 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2449 int index = invoke_method_table()->hash_to_index(hash);
2450 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2451 methodHandle m;
2452 if (spe == NULL || spe->method() == NULL) {
2453 spe = NULL;
2454 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2455 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2456 if (!Arguments::is_interpreter_only()) {
2457 // Generate a compiled form of the MH intrinsic.
2458 AdapterHandlerLibrary::create_native_wrapper(m);
2459 // Check if have the compiled code.
2460 if (!m->has_compiled_code()) {
2461 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2462 "Out of space in CodeCache for method handle intrinsic", empty);
2463 }
2464 }
2465 // Now grab the lock. We might have to throw away the new method,
2466 // if a racing thread has managed to install one at the same time.
2467 {
2468 MutexLocker ml(SystemDictionary_lock, THREAD);
2469 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2470 if (spe == NULL)
2471 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2472 if (spe->method() == NULL)
2473 spe->set_method(m());
2474 }
2475 }
2476
2477 assert(spe != NULL && spe->method() != NULL, "");
2478 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2479 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2480 "MH intrinsic invariant");
2481 return spe->method();
2482 }
2483
2484 // Helper for unpacking the return value from linkMethod and linkCallSite.
2485 static methodHandle unpack_method_and_appendix(Handle mname,
2486 Klass* accessing_klass,
2487 objArrayHandle appendix_box,
2488 Handle* appendix_result,
2489 TRAPS) {
2490 methodHandle empty;
2491 if (mname.not_null()) {
2492 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2493 if (m != NULL) {
2494 oop appendix = appendix_box->obj_at(0);
2495 if (TraceMethodHandles) {
2496 #ifndef PRODUCT
2497 ttyLocker ttyl;
2498 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2499 m->print();
2500 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2501 tty->cr();
2502 #endif //PRODUCT
2503 }
2504 (*appendix_result) = Handle(THREAD, appendix);
2505 // the target is stored in the cpCache and if a reference to this
2506 // MemberName is dropped we need a way to make sure the
2507 // class_loader containing this method is kept alive.
2508 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2509 this_key->record_dependency(m->method_holder());
2510 return methodHandle(THREAD, m);
2511 }
2512 }
2513 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2514 return empty;
2515 }
2516
2517 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2518 Symbol* name,
2519 Symbol* signature,
2520 Klass* accessing_klass,
2521 Handle *appendix_result,
2522 Handle *method_type_result,
2523 TRAPS) {
2524 methodHandle empty;
2525 assert(THREAD->can_call_java() ,"");
2526 Handle method_type =
2527 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2528
2529 int ref_kind = JVM_REF_invokeVirtual;
2530 oop name_oop = StringTable::intern(name, CHECK_(empty));
2531 Handle name_str (THREAD, name_oop);
2532 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2533 assert(appendix_box->obj_at(0) == NULL, "");
2534
2535 // This should not happen. JDK code should take care of that.
2536 if (accessing_klass == NULL || method_type.is_null()) {
2537 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2538 }
2539
2540 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2541 JavaCallArguments args;
2542 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2543 args.push_int(ref_kind);
2544 args.push_oop(Handle(THREAD, klass->java_mirror()));
2545 args.push_oop(name_str);
2546 args.push_oop(method_type);
2547 args.push_oop(appendix_box);
2548 JavaValue result(T_OBJECT);
2549 JavaCalls::call_static(&result,
2550 SystemDictionary::MethodHandleNatives_klass(),
2551 vmSymbols::linkMethod_name(),
2552 vmSymbols::linkMethod_signature(),
2553 &args, CHECK_(empty));
2554 Handle mname(THREAD, (oop) result.get_jobject());
2555 (*method_type_result) = method_type;
2556 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2557 }
2558
2559 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2560 // We must ensure that all class loaders everywhere will reach this class, for any client.
2561 // This is a safe bet for public classes in java.lang, such as Object and String.
2562 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2563 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2564 static bool is_always_visible_class(oop mirror) {
2565 Klass* klass = java_lang_Class::as_Klass(mirror);
2566 if (klass->is_objArray_klass()) {
2567 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2568 }
2569 if (klass->is_typeArray_klass()) {
2570 return true; // primitive array
2571 }
2572 assert(klass->is_instance_klass(), "%s", klass->external_name());
2573 return klass->is_public() &&
2574 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2575 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2576 }
2577
2578
2579 // Return the Java mirror (java.lang.Class instance) for a single-character
2580 // descriptor. This result, when available, is the same as produced by the
2581 // heavier API point of the same name that takes a Symbol.
2582 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2583 return java_lang_Class::primitive_mirror(char2type(signature_char));
2584 }
2585
2586 // Find or construct the Java mirror (java.lang.Class instance) for a
2587 // for the given field type signature, as interpreted relative to the
2588 // given class loader. Handles primitives, void, references, arrays,
2589 // and all other reflectable types, except method types.
2590 // N.B. Code in reflection should use this entry point.
2591 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2592 Klass* accessing_klass,
2593 Handle class_loader,
2594 Handle protection_domain,
2595 SignatureStream::FailureMode failure_mode,
2596 TRAPS) {
2597 Handle empty;
2598
2599 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2600 "one or the other, or perhaps neither");
2601
2602 Symbol* type = signature;
2603
2604 // What we have here must be a valid field descriptor,
2605 // and all valid field descriptors are supported.
2606 // Produce the same java.lang.Class that reflection reports.
2607 if (type->utf8_length() == 1) {
2608
2609 // It's a primitive. (Void has a primitive mirror too.)
2610 char ch = type->char_at(0);
2611 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2612 return Handle(THREAD, find_java_mirror_for_type(ch));
2613
2614 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2615
2616 // It's a reference type.
2617 if (accessing_klass != NULL) {
2618 class_loader = Handle(THREAD, accessing_klass->class_loader());
2619 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2620 }
2621 Klass* constant_type_klass;
2622 if (failure_mode == SignatureStream::ReturnNull) {
2623 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2624 CHECK_(empty));
2625 } else {
2626 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2627 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2628 throw_error, CHECK_(empty));
2629 }
2630 if (constant_type_klass == NULL) {
2631 return Handle(); // report failure this way
2632 }
2633 Handle mirror(THREAD, constant_type_klass->java_mirror());
2634
2635 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2636 if (accessing_klass != NULL) {
2637 Klass* sel_klass = constant_type_klass;
2638 bool fold_type_to_class = true;
2639 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2640 fold_type_to_class, CHECK_(empty));
2641 }
2642
2643 return mirror;
2644
2645 }
2646
2647 // Fall through to an error.
2648 assert(false, "unsupported mirror syntax");
2649 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2650 }
2651
2652
2653 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2654 // signature, as interpreted relative to the given class loader.
2655 // Because of class loader constraints, all method handle usage must be
2656 // consistent with this loader.
2657 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2658 Klass* accessing_klass,
2659 TRAPS) {
2660 Handle empty;
2661 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2662 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2663 int index = invoke_method_table()->hash_to_index(hash);
2664 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2665 if (spe != NULL && spe->method_type() != NULL) {
2666 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2667 return Handle(THREAD, spe->method_type());
2668 } else if (!THREAD->can_call_java()) {
2669 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2670 return Handle(); // do not attempt from within compiler, unless it was cached
2671 }
2672
2673 Handle class_loader, protection_domain;
2674 if (accessing_klass != NULL) {
2675 class_loader = Handle(THREAD, accessing_klass->class_loader());
2676 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2677 }
2678 bool can_be_cached = true;
2679 int npts = ArgumentCount(signature).size();
2680 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2681 int arg = 0;
2682 Handle rt; // the return type from the signature
2683 ResourceMark rm(THREAD);
2684 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2685 oop mirror = NULL;
2686 if (can_be_cached) {
2687 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2688 mirror = ss.as_java_mirror(Handle(), Handle(),
2689 SignatureStream::ReturnNull, CHECK_(empty));
2690 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2691 // Fall back to accessing_klass context.
2692 can_be_cached = false;
2693 }
2694 }
2695 if (!can_be_cached) {
2696 // Resolve, throwing a real error if it doesn't work.
2697 mirror = ss.as_java_mirror(class_loader, protection_domain,
2698 SignatureStream::NCDFError, CHECK_(empty));
2699 }
2700 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2701 if (ss.at_return_type())
2702 rt = Handle(THREAD, mirror);
2703 else
2704 pts->obj_at_put(arg++, mirror);
2705
2706 // Check accessibility.
2707 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2708 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2709 mirror = NULL; // safety
2710 // Emulate ConstantPool::verify_constant_pool_resolve.
2711 bool fold_type_to_class = true;
2712 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2713 fold_type_to_class, CHECK_(empty));
2714 }
2715 }
2716 assert(arg == npts, "");
2717
2718 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2719 JavaCallArguments args(Handle(THREAD, rt()));
2720 args.push_oop(pts);
2721 JavaValue result(T_OBJECT);
2722 JavaCalls::call_static(&result,
2723 SystemDictionary::MethodHandleNatives_klass(),
2724 vmSymbols::findMethodHandleType_name(),
2725 vmSymbols::findMethodHandleType_signature(),
2726 &args, CHECK_(empty));
2727 Handle method_type(THREAD, (oop) result.get_jobject());
2728
2729 if (can_be_cached) {
2730 // We can cache this MethodType inside the JVM.
2731 MutexLocker ml(SystemDictionary_lock, THREAD);
2732 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2733 if (spe == NULL)
2734 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2735 if (spe->method_type() == NULL) {
2736 spe->set_method_type(method_type());
2737 }
2738 }
2739
2740 // report back to the caller with the MethodType
2741 return method_type;
2742 }
2743
2744 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2745 Klass* accessing_klass,
2746 TRAPS) {
2747 Handle empty;
2748 ResourceMark rm(THREAD);
2749 SignatureStream ss(signature, /*is_method=*/ false);
2750 if (!ss.is_done()) {
2751 Handle class_loader, protection_domain;
2752 if (accessing_klass != NULL) {
2753 class_loader = Handle(THREAD, accessing_klass->class_loader());
2754 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2755 }
2756 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2757 ss.next();
2758 if (ss.is_done()) {
2759 return Handle(THREAD, mirror);
2760 }
2761 }
2762 return empty;
2763 }
2764
2765 // Ask Java code to find or construct a method handle constant.
2766 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2767 int ref_kind, //e.g., JVM_REF_invokeVirtual
2768 Klass* callee,
2769 Symbol* name,
2770 Symbol* signature,
2771 TRAPS) {
2772 Handle empty;
2773 if (caller == NULL) {
2774 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2775 }
2776 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2777 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2778
2779 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2780 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2781 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2782 java_lang_invoke_MemberName::set_name (mname(), name_str());
2783 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2784 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2785
2786 if (ref_kind == JVM_REF_invokeVirtual &&
2787 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2788 // Skip resolution for public signature polymorphic methods such as
2789 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2790 // They require appendix argument which MemberName resolution doesn't handle.
2791 // There's special logic on JDK side to handle them
2792 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2793 } else {
2794 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2795 }
2796
2797 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2798 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2799
2800 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2801 JavaCallArguments args;
2802 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2803 args.push_int(ref_kind);
2804 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2805 args.push_oop(name_str);
2806 args.push_oop(type);
2807 JavaValue result(T_OBJECT);
2808 JavaCalls::call_static(&result,
2809 SystemDictionary::MethodHandleNatives_klass(),
2810 vmSymbols::linkMethodHandleConstant_name(),
2811 vmSymbols::linkMethodHandleConstant_signature(),
2812 &args, CHECK_(empty));
2813 return Handle(THREAD, (oop) result.get_jobject());
2814 }
2815
2816 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2817 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2818 int condy_index,
2819 Handle bootstrap_specifier,
2820 Symbol* name,
2821 Symbol* type,
2822 TRAPS) {
2823 Handle empty;
2824 Handle bsm, info;
2825 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2826 bsm = bootstrap_specifier;
2827 } else {
2828 assert(bootstrap_specifier->is_objArray(), "");
2829 objArrayOop args = (objArrayOop) bootstrap_specifier();
2830 assert(args->length() == 2, "");
2831 bsm = Handle(THREAD, args->obj_at(0));
2832 info = Handle(THREAD, args->obj_at(1));
2833 }
2834 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2835 "caller must supply a valid BSM");
2836
2837 // This should not happen. JDK code should take care of that.
2838 if (caller == NULL) {
2839 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2840 }
2841
2842 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2843
2844 // Resolve the constant type in the context of the caller class
2845 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2846 CHECK_(empty));
2847
2848 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2849 JavaCallArguments args;
2850 args.push_oop(Handle(THREAD, caller->java_mirror()));
2851 args.push_int(condy_index);
2852 args.push_oop(bsm);
2853 args.push_oop(constant_name);
2854 args.push_oop(type_mirror);
2855 args.push_oop(info);
2856 JavaValue result(T_OBJECT);
2857 JavaCalls::call_static(&result,
2858 SystemDictionary::MethodHandleNatives_klass(),
2859 vmSymbols::linkDynamicConstant_name(),
2860 vmSymbols::linkDynamicConstant_signature(),
2861 &args, CHECK_(empty));
2862
2863 return Handle(THREAD, (oop) result.get_jobject());
2864 }
2865
2866 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2867 // name and signature, as interpreted relative to the given class loader.
2868 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2869 int indy_index,
2870 Handle bootstrap_specifier,
2871 Symbol* name,
2872 Symbol* type,
2873 Handle *appendix_result,
2874 Handle *method_type_result,
2875 TRAPS) {
2876 methodHandle empty;
2877 Handle bsm, info;
2878 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2879 bsm = bootstrap_specifier;
2880 } else {
2881 objArrayOop args = (objArrayOop) bootstrap_specifier();
2882 assert(args->length() == 2, "");
2883 bsm = Handle(THREAD, args->obj_at(0));
2884 info = Handle(THREAD, args->obj_at(1));
2885 }
2886 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2887 "caller must supply a valid BSM");
2888
2889 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2890 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2891
2892 // This should not happen. JDK code should take care of that.
2893 if (caller == NULL || method_type.is_null()) {
2894 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2895 }
2896
2897 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2898 assert(appendix_box->obj_at(0) == NULL, "");
2899
2900 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2901 JavaCallArguments args;
2902 args.push_oop(Handle(THREAD, caller->java_mirror()));
2903 args.push_int(indy_index);
2904 args.push_oop(bsm);
2905 args.push_oop(method_name);
2906 args.push_oop(method_type);
2907 args.push_oop(info);
2908 args.push_oop(appendix_box);
2909 JavaValue result(T_OBJECT);
2910 JavaCalls::call_static(&result,
2911 SystemDictionary::MethodHandleNatives_klass(),
2912 vmSymbols::linkCallSite_name(),
2913 vmSymbols::linkCallSite_signature(),
2914 &args, CHECK_(empty));
2915 Handle mname(THREAD, (oop) result.get_jobject());
2916 (*method_type_result) = method_type;
2917 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2918 }
2919
2920 // Protection domain cache table handling
2921
2922 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2923 return _pd_cache_table->get(protection_domain);
2924 }
2925
2926 #if INCLUDE_CDS
2927 void SystemDictionary::reorder_dictionary_for_sharing() {
2928 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2929 }
2930 #endif
2931
2932 size_t SystemDictionary::count_bytes_for_buckets() {
2933 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2934 }
2935
2936 size_t SystemDictionary::count_bytes_for_table() {
2937 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2938 }
2939
2940 void SystemDictionary::copy_buckets(char* top, char* end) {
2941 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2942 }
2943
2944 void SystemDictionary::copy_table(char* top, char* end) {
2945 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2946 }
2947
2948 // ----------------------------------------------------------------------------
2949 void SystemDictionary::print_shared(outputStream *st) {
2950 shared_dictionary()->print_on(st);
2951 }
2952
2953 void SystemDictionary::print_on(outputStream *st) {
2954 if (shared_dictionary() != NULL) {
2955 st->print_cr("Shared Dictionary");
2956 shared_dictionary()->print_on(st);
2957 st->cr();
2958 }
2959
2960 GCMutexLocker mu(SystemDictionary_lock);
2961
2962 ClassLoaderDataGraph::print_dictionary(st);
2963
2964 // Placeholders
2965 placeholders()->print_on(st);
2966 st->cr();
2967
2968 // loader constraints - print under SD_lock
2969 constraints()->print_on(st);
2970 st->cr();
2971
2972 _pd_cache_table->print_on(st);
2973 st->cr();
2974 }
2975
2976 void SystemDictionary::verify() {
2977 guarantee(constraints() != NULL,
2978 "Verify of loader constraints failed");
2979 guarantee(placeholders()->number_of_entries() >= 0,
2980 "Verify of placeholders failed");
2981
2982 GCMutexLocker mu(SystemDictionary_lock);
2983
2984 // Verify dictionary
2985 ClassLoaderDataGraph::verify_dictionary();
2986
2987 placeholders()->verify();
2988
2989 // Verify constraint table
2990 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2991 constraints()->verify(placeholders());
2992
2993 _pd_cache_table->verify();
2994 }
2995
2996 void SystemDictionary::dump(outputStream *st, bool verbose) {
2997 assert_locked_or_safepoint(SystemDictionary_lock);
2998 if (verbose) {
2999 print_on(st);
3000 } else {
3001 if (shared_dictionary() != NULL) {
3002 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3003 }
3004 ClassLoaderDataGraph::print_dictionary_statistics(st);
3005 placeholders()->print_table_statistics(st, "Placeholder Table");
3006 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3007 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3008 }
3009 }
3010
3011 // Utility for dumping dictionaries.
3012 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3013 DCmdWithParser(output, heap),
3014 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3015 "BOOLEAN", false, "false") {
3016 _dcmdparser.add_dcmd_option(&_verbose);
3017 }
3018
3019 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3020 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3021 _verbose.value());
3022 VMThread::execute(&dumper);
3023 }
3024
3025 int SystemDictionaryDCmd::num_arguments() {
3026 ResourceMark rm;
3027 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3028 if (dcmd != NULL) {
3029 DCmdMark mark(dcmd);
3030 return dcmd->_dcmdparser.num_arguments();
3031 } else {
3032 return 0;
3033 }
3034 }
3035
3036 class CombineDictionariesClosure : public CLDClosure {
3037 private:
3038 Dictionary* _master_dictionary;
3039 public:
3040 CombineDictionariesClosure(Dictionary* master_dictionary) :
3041 _master_dictionary(master_dictionary) {}
3042 void do_cld(ClassLoaderData* cld) {
3043 ResourceMark rm;
3044 if (cld->is_shortlived()) {
3045 return;
3046 }
3047 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3048 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3049 Dictionary* curr_dictionary = cld->dictionary();
3050 DictionaryEntry* p = curr_dictionary->bucket(i);
3051 while (p != NULL) {
3052 Symbol* name = p->instance_klass()->name();
3053 unsigned int d_hash = _master_dictionary->compute_hash(name);
3054 int d_index = _master_dictionary->hash_to_index(d_hash);
3055 DictionaryEntry* next = p->next();
3056 if (p->literal()->class_loader_data() != cld) {
3057 // This is an initiating class loader entry; don't use it
3058 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3059 curr_dictionary->free_entry(p);
3060 } else {
3061 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3062 curr_dictionary->unlink_entry(p);
3063 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3064 _master_dictionary->add_entry(d_index, p);
3065 }
3066 p = next;
3067 }
3068 *curr_dictionary->bucket_addr(i) = NULL;
3069 }
3070 }
3071 }
3072 };
3073
3074 // Combining platform and system loader dictionaries into boot loader dictionary.
3075 // During run time, we only have one shared dictionary.
3076 void SystemDictionary::combine_shared_dictionaries() {
3077 assert(DumpSharedSpaces, "dump time only");
3078 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3079 CombineDictionariesClosure cdc(master_dictionary);
3080 ClassLoaderDataGraph::cld_do(&cdc);
3081
3082 // These tables are no longer valid or necessary. Keeping them around will
3083 // cause SystemDictionary::verify() to fail. Let's empty them.
3084 _placeholders = new PlaceholderTable(_placeholder_table_size);
3085 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3086
3087 NOT_PRODUCT(SystemDictionary::verify());
3088 }
3089
3090 void SystemDictionary::initialize_oop_storage() {
3091 _vm_weak_oop_storage =
3092 new OopStorage("VM Weak Oop Handles",
3093 VMWeakAlloc_lock,
3094 VMWeakActive_lock);
3095 }
3096
3097 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3098 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3099 return _vm_weak_oop_storage;
3100 }