1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/methodData.hpp"
60 #include "oops/objArrayKlass.hpp"
61 #include "oops/objArrayOop.inline.hpp"
62 #include "oops/oop.inline.hpp"
63 #include "oops/symbol.hpp"
64 #include "oops/typeArrayKlass.hpp"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/arguments_ext.hpp"
70 #include "runtime/biasedLocking.hpp"
71 #include "runtime/fieldType.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/java.hpp"
74 #include "runtime/javaCalls.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.inline.hpp"
77 #include "runtime/signature.hpp"
78 #include "services/classLoadingService.hpp"
79 #include "services/diagnosticCommand.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/tracing.hpp"
82 #include "utilities/macros.hpp"
83 #if INCLUDE_CDS
84 #include "classfile/sharedClassUtil.hpp"
85 #include "classfile/systemDictionaryShared.hpp"
86 #endif
87 #if INCLUDE_JVMCI
88 #include "jvmci/jvmciRuntime.hpp"
89 #endif
90
91 PlaceholderTable* SystemDictionary::_placeholders = NULL;
92 Dictionary* SystemDictionary::_shared_dictionary = NULL;
93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
97
98 int SystemDictionary::_number_of_modifications = 0;
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107 oop SystemDictionary::_java_platform_loader = NULL;
108
109 bool SystemDictionary::_has_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149
150 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
151 }
152
153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
155 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
156 }
157
158 // ----------------------------------------------------------------------------
159 // Parallel class loading check
160
161 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
162 if (UnsyncloadClass || class_loader.is_null()) return true;
163 if (AlwaysLockClassLoader) return false;
164 return java_lang_ClassLoader::parallelCapable(class_loader());
165 }
166 // ----------------------------------------------------------------------------
167 // ParallelDefineClass flag does not apply to bootclass loader
168 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
169 if (class_loader.is_null()) return false;
170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
171 return true;
172 }
173 return false;
174 }
175
176 // Returns true if the passed class loader is the builtin application class loader
177 // or a custom system class loader. A customer system class loader can be
178 // specified via -Djava.system.class.loader.
179 bool SystemDictionary::is_system_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
184 class_loader == _java_system_loader);
185 }
186
187 // Returns true if the passed class loader is the platform class loader.
188 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
189 if (class_loader == NULL) {
190 return false;
191 }
192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
193 }
194
195 // ----------------------------------------------------------------------------
196 // Resolving of classes
197
198 // Forwards to resolve_or_null
199
200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
202 if (HAS_PENDING_EXCEPTION || klass == NULL) {
203 // can return a null klass
204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
205 }
206 return klass;
207 }
208
209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
210 bool throw_error,
211 Klass* klass, TRAPS) {
212 if (HAS_PENDING_EXCEPTION) {
213 // If we have a pending exception we forward it to the caller, unless throw_error is true,
214 // in which case we have to check whether the pending exception is a ClassNotFoundException,
215 // and if so convert it to a NoClassDefFoundError
216 // And chain the original ClassNotFoundException
217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
218 ResourceMark rm(THREAD);
219 assert(klass == NULL, "Should not have result with exception pending");
220 Handle e(THREAD, PENDING_EXCEPTION);
221 CLEAR_PENDING_EXCEPTION;
222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
223 } else {
224 return NULL;
225 }
226 }
227 // Class not found, throw appropriate error or exception depending on value of throw_error
228 if (klass == NULL) {
229 ResourceMark rm(THREAD);
230 if (throw_error) {
231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
232 } else {
233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
234 }
235 }
236 return klass;
237 }
238
239
240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
241 bool throw_error, TRAPS)
242 {
243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
244 }
245
246
247 // Forwards to resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 assert(THREAD->can_call_java(),
251 "can not load classes with compiler thread: class=%s, classloader=%s",
252 class_name->as_C_string(),
253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
254 if (FieldType::is_array(class_name)) {
255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 } else if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2, CHECK_NULL);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* class_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for CDS dump time.
348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(SystemDictionary_lock, THREAD);
381 Klass* childk = find_class(d_hash, child_name, dictionary);
382 Klass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if class_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->super()) != NULL) &&
391
392 ((quicksuperk->name() == class_name) &&
393 (quicksuperk->class_loader() == class_loader()))) {
394 return quicksuperk;
395 } else {
396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
398 throw_circularity_error = true;
399 }
400 }
401 if (!throw_circularity_error) {
402 // Be careful not to exit resolve_super
403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
404 }
405 }
406 if (throw_circularity_error) {
407 ResourceMark rm(THREAD);
408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
409 }
410
411 // java.lang.Object should have been found above
412 assert(class_name != NULL, "null super class for resolving");
413 // Resolve the super class or interface, check results on return
414 Klass* superk = SystemDictionary::resolve_or_null(class_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 superk = handle_resolution_exception(class_name, true, superk, THREAD);
433 }
434
435 return superk;
436 }
437
438 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
439 Handle class_loader,
440 Handle protection_domain,
441 TRAPS) {
442 if(!has_checkPackageAccess()) return;
443
444 // Now we have to call back to java to check if the initating class has access
445 JavaValue result(T_VOID);
446 LogTarget(Debug, protectiondomain) lt;
447 if (lt.is_enabled()) {
448 ResourceMark rm;
449 // Print out trace information
450 LogStream ls(lt);
451 ls.print_cr("Checking package access");
452 ls.print("class loader: "); class_loader()->print_value_on(&ls);
453 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
454 ls.print(" loading: "); klass->print_value_on(&ls);
455 ls.cr();
456 }
457
458 // This handle and the class_loader handle passed in keeps this class from
459 // being unloaded through several GC points.
460 // The class_loader handle passed in is the initiating loader.
461 Handle mirror(THREAD, klass->java_mirror());
462
463 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
464 JavaCalls::call_special(&result,
465 class_loader,
466 system_loader,
467 vmSymbols::checkPackageAccess_name(),
468 vmSymbols::class_protectiondomain_signature(),
469 mirror,
470 protection_domain,
471 THREAD);
472
473 if (HAS_PENDING_EXCEPTION) {
474 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
475 } else {
476 log_debug(protectiondomain)("granted");
477 }
478
479 if (HAS_PENDING_EXCEPTION) return;
480
481 // If no exception has been thrown, we have validated the protection domain
482 // Insert the protection domain of the initiating class into the set.
483 {
484 ClassLoaderData* loader_data = class_loader_data(class_loader);
485 Dictionary* dictionary = loader_data->dictionary();
486
487 Symbol* kn = klass->name();
488 unsigned int d_hash = dictionary->compute_hash(kn);
489
490 MutexLocker mu(SystemDictionary_lock, THREAD);
491 int d_index = dictionary->hash_to_index(d_hash);
492 dictionary->add_protection_domain(d_index, d_hash, klass,
493 protection_domain, THREAD);
494 }
495 }
496
497 // We only get here if this thread finds that another thread
498 // has already claimed the placeholder token for the current operation,
499 // but that other thread either never owned or gave up the
500 // object lock
501 // Waits on SystemDictionary_lock to indicate placeholder table updated
502 // On return, caller must recheck placeholder table state
503 //
504 // We only get here if
505 // 1) custom classLoader, i.e. not bootstrap classloader
506 // 2) UnsyncloadClass not set
507 // 3) custom classLoader has broken the class loader objectLock
508 // so another thread got here in parallel
509 //
510 // lockObject must be held.
511 // Complicated dance due to lock ordering:
512 // Must first release the classloader object lock to
513 // allow initial definer to complete the class definition
514 // and to avoid deadlock
515 // Reclaim classloader lock object with same original recursion count
516 // Must release SystemDictionary_lock after notify, since
517 // class loader lock must be claimed before SystemDictionary_lock
518 // to prevent deadlocks
519 //
520 // The notify allows applications that did an untimed wait() on
521 // the classloader object lock to not hang.
522 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
523 assert_lock_strong(SystemDictionary_lock);
524
525 bool calledholdinglock
526 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
527 assert(calledholdinglock,"must hold lock for notify");
528 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
529 ObjectSynchronizer::notifyall(lockObject, THREAD);
530 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
531 SystemDictionary_lock->wait();
532 SystemDictionary_lock->unlock();
533 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
534 SystemDictionary_lock->lock();
535 }
536
537 // If the class in is in the placeholder table, class loading is in progress
538 // For cases where the application changes threads to load classes, it
539 // is critical to ClassCircularity detection that we try loading
540 // the superclass on the same thread internally, so we do parallel
541 // super class loading here.
542 // This also is critical in cases where the original thread gets stalled
543 // even in non-circularity situations.
544 // Note: must call resolve_super_or_fail even if null super -
545 // to force placeholder entry creation for this class for circularity detection
546 // Caller must check for pending exception
547 // Returns non-null Klass* if other thread has completed load
548 // and we are done,
549 // If return null Klass* and no pending exception, the caller must load the class
550 InstanceKlass* SystemDictionary::handle_parallel_super_load(
551 Symbol* name, Symbol* superclassname, Handle class_loader,
552 Handle protection_domain, Handle lockObject, TRAPS) {
553
554 ClassLoaderData* loader_data = class_loader_data(class_loader);
555 Dictionary* dictionary = loader_data->dictionary();
556 unsigned int d_hash = dictionary->compute_hash(name);
557 unsigned int p_hash = placeholders()->compute_hash(name);
558 int p_index = placeholders()->hash_to_index(p_hash);
559
560 // superk is not used, resolve_super called for circularity check only
561 // This code is reached in two situations. One if this thread
562 // is loading the same class twice (e.g. ClassCircularity, or
563 // java.lang.instrument).
564 // The second is if another thread started the resolve_super first
565 // and has not yet finished.
566 // In both cases the original caller will clean up the placeholder
567 // entry on error.
568 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
569 superclassname,
570 class_loader,
571 protection_domain,
572 true,
573 CHECK_NULL);
574
575 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
576 // Serial class loaders and bootstrap classloader do wait for superclass loads
577 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
578 MutexLocker mu(SystemDictionary_lock, THREAD);
579 // Check if classloading completed while we were loading superclass or waiting
580 return find_class(d_hash, name, dictionary);
581 }
582
583 // must loop to both handle other placeholder updates
584 // and spurious notifications
585 bool super_load_in_progress = true;
586 PlaceholderEntry* placeholder;
587 while (super_load_in_progress) {
588 MutexLocker mu(SystemDictionary_lock, THREAD);
589 // Check if classloading completed while we were loading superclass or waiting
590 InstanceKlass* check = find_class(d_hash, name, dictionary);
591 if (check != NULL) {
592 // Klass is already loaded, so just return it
593 return check;
594 } else {
595 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
596 if (placeholder && placeholder->super_load_in_progress() ){
597 // Before UnsyncloadClass:
598 // We only get here if the application has released the
599 // classloader lock when another thread was in the middle of loading a
600 // superclass/superinterface for this class, and now
601 // this thread is also trying to load this class.
602 // To minimize surprises, the first thread that started to
603 // load a class should be the one to complete the loading
604 // with the classfile it initially expected.
605 // This logic has the current thread wait once it has done
606 // all the superclass/superinterface loading it can, until
607 // the original thread completes the class loading or fails
608 // If it completes we will use the resulting InstanceKlass
609 // which we will find below in the systemDictionary.
610 // We also get here for parallel bootstrap classloader
611 if (class_loader.is_null()) {
612 SystemDictionary_lock->wait();
613 } else {
614 double_lock_wait(lockObject, THREAD);
615 }
616 } else {
617 // If not in SD and not in PH, other thread's load must have failed
618 super_load_in_progress = false;
619 }
620 }
621 }
622 return NULL;
623 }
624
625 static void post_class_load_event(EventClassLoad* event,
626 const InstanceKlass* k,
627 const ClassLoaderData* init_cld) {
628 #if INCLUDE_TRACE
629 assert(event != NULL, "invariant");
630 assert(k != NULL, "invariant");
631 if (event->should_commit()) {
632 event->set_loadedClass(k);
633 event->set_definingClassLoader(k->class_loader_data());
634 event->set_initiatingClassLoader(init_cld);
635 event->commit();
636 }
637 #endif // INCLUDE_TRACE
638 }
639
640 static void class_define_event(InstanceKlass* k,
641 const ClassLoaderData* def_cld) {
642 #if INCLUDE_TRACE
643 EventClassDefine event;
644 if (event.should_commit()) {
645 event.set_definedClass(k);
646 event.set_definingClassLoader(def_cld);
647 event.commit();
648 }
649 #endif // INCLUDE_TRACE
650 }
651
652 // Be careful when modifying this code: once you have run
653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
654 // you need to find_and_remove it before returning.
655 // So be careful to not exit with a CHECK_ macro betweeen these calls.
656 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
657 Handle class_loader,
658 Handle protection_domain,
659 TRAPS) {
660 assert(name != NULL && !FieldType::is_array(name) &&
661 !FieldType::is_obj(name), "invalid class name");
662
663 EventClassLoad class_load_start_event;
664
665 HandleMark hm(THREAD);
666
667 // Fix for 4474172; see evaluation for more details
668 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
669 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
670 Dictionary* dictionary = loader_data->dictionary();
671 unsigned int d_hash = dictionary->compute_hash(name);
672
673 // Do lookup to see if class already exist and the protection domain
674 // has the right access
675 // This call uses find which checks protection domain already matches
676 // All subsequent calls use find_class, and set has_loaded_class so that
677 // before we return a result we call out to java to check for valid protection domain
678 // to allow returning the Klass* and add it to the pd_set if it is valid
679 {
680 Klass* probe = dictionary->find(d_hash, name, protection_domain);
681 if (probe != NULL) return probe;
682 }
683
684 // Non-bootstrap class loaders will call out to class loader and
685 // define via jvm/jni_DefineClass which will acquire the
686 // class loader object lock to protect against multiple threads
687 // defining the class in parallel by accident.
688 // This lock must be acquired here so the waiter will find
689 // any successful result in the SystemDictionary and not attempt
690 // the define
691 // ParallelCapable Classloaders and the bootstrap classloader,
692 // or all classloaders with UnsyncloadClass do not acquire lock here
693 bool DoObjectLock = true;
694 if (is_parallelCapable(class_loader)) {
695 DoObjectLock = false;
696 }
697
698 unsigned int p_hash = placeholders()->compute_hash(name);
699 int p_index = placeholders()->hash_to_index(p_hash);
700
701 // Class is not in SystemDictionary so we have to do loading.
702 // Make sure we are synchronized on the class loader before we proceed
703 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
704 check_loader_lock_contention(lockObject, THREAD);
705 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
706
707 // Check again (after locking) if class already exist in SystemDictionary
708 bool class_has_been_loaded = false;
709 bool super_load_in_progress = false;
710 bool havesupername = false;
711 InstanceKlass* k = NULL;
712 PlaceholderEntry* placeholder;
713 Symbol* superclassname = NULL;
714
715 {
716 MutexLocker mu(SystemDictionary_lock, THREAD);
717 InstanceKlass* check = find_class(d_hash, name, dictionary);
718 if (check != NULL) {
719 // Klass is already loaded, so just return it
720 class_has_been_loaded = true;
721 k = check;
722 } else {
723 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (placeholder && placeholder->super_load_in_progress()) {
725 super_load_in_progress = true;
726 if (placeholder->havesupername() == true) {
727 superclassname = placeholder->supername();
728 havesupername = true;
729 }
730 }
731 }
732 }
733
734 // If the class is in the placeholder table, class loading is in progress
735 if (super_load_in_progress && havesupername==true) {
736 k = handle_parallel_super_load(name,
737 superclassname,
738 class_loader,
739 protection_domain,
740 lockObject, THREAD);
741 if (HAS_PENDING_EXCEPTION) {
742 return NULL;
743 }
744 if (k != NULL) {
745 class_has_been_loaded = true;
746 }
747 }
748
749 bool throw_circularity_error = false;
750 if (!class_has_been_loaded) {
751 bool load_instance_added = false;
752
753 // add placeholder entry to record loading instance class
754 // Five cases:
755 // All cases need to prevent modifying bootclasssearchpath
756 // in parallel with a classload of same classname
757 // Redefineclasses uses existence of the placeholder for the duration
758 // of the class load to prevent concurrent redefinition of not completely
759 // defined classes.
760 // case 1. traditional classloaders that rely on the classloader object lock
761 // - no other need for LOAD_INSTANCE
762 // case 2. traditional classloaders that break the classloader object lock
763 // as a deadlock workaround. Detection of this case requires that
764 // this check is done while holding the classloader object lock,
765 // and that lock is still held when calling classloader's loadClass.
766 // For these classloaders, we ensure that the first requestor
767 // completes the load and other requestors wait for completion.
768 // case 3. UnsyncloadClass - don't use objectLocker
769 // With this flag, we allow parallel classloading of a
770 // class/classloader pair
771 // case4. Bootstrap classloader - don't own objectLocker
772 // This classloader supports parallelism at the classloader level,
773 // but only allows a single load of a class/classloader pair.
774 // No performance benefit and no deadlock issues.
775 // case 5. parallelCapable user level classloaders - without objectLocker
776 // Allow parallel classloading of a class/classloader pair
777
778 {
779 MutexLocker mu(SystemDictionary_lock, THREAD);
780 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
781 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
782 if (oldprobe) {
783 // only need check_seen_thread once, not on each loop
784 // 6341374 java/lang/Instrument with -Xcomp
785 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
786 throw_circularity_error = true;
787 } else {
788 // case 1: traditional: should never see load_in_progress.
789 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
790
791 // case 4: bootstrap classloader: prevent futile classloading,
792 // wait on first requestor
793 if (class_loader.is_null()) {
794 SystemDictionary_lock->wait();
795 } else {
796 // case 2: traditional with broken classloader lock. wait on first
797 // requestor.
798 double_lock_wait(lockObject, THREAD);
799 }
800 // Check if classloading completed while we were waiting
801 InstanceKlass* check = find_class(d_hash, name, dictionary);
802 if (check != NULL) {
803 // Klass is already loaded, so just return it
804 k = check;
805 class_has_been_loaded = true;
806 }
807 // check if other thread failed to load and cleaned up
808 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
809 }
810 }
811 }
812 }
813 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
814 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
815 // LOAD_INSTANCE in parallel
816
817 if (!throw_circularity_error && !class_has_been_loaded) {
818 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
819 load_instance_added = true;
820 // For class loaders that do not acquire the classloader object lock,
821 // if they did not catch another thread holding LOAD_INSTANCE,
822 // need a check analogous to the acquire ObjectLocker/find_class
823 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
824 // one final check if the load has already completed
825 // class loaders holding the ObjectLock shouldn't find the class here
826 InstanceKlass* check = find_class(d_hash, name, dictionary);
827 if (check != NULL) {
828 // Klass is already loaded, so return it after checking/adding protection domain
829 k = check;
830 class_has_been_loaded = true;
831 }
832 }
833 }
834
835 // must throw error outside of owning lock
836 if (throw_circularity_error) {
837 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
838 ResourceMark rm(THREAD);
839 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
840 }
841
842 if (!class_has_been_loaded) {
843
844 // Do actual loading
845 k = load_instance_class(name, class_loader, THREAD);
846
847 // For UnsyncloadClass only
848 // If they got a linkageError, check if a parallel class load succeeded.
849 // If it did, then for bytecode resolution the specification requires
850 // that we return the same result we did for the other thread, i.e. the
851 // successfully loaded InstanceKlass
852 // Should not get here for classloaders that support parallelism
853 // with the new cleaner mechanism, even with AllowParallelDefineClass
854 // Bootstrap goes through here to allow for an extra guarantee check
855 if (UnsyncloadClass || (class_loader.is_null())) {
856 if (k == NULL && HAS_PENDING_EXCEPTION
857 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
858 MutexLocker mu(SystemDictionary_lock, THREAD);
859 InstanceKlass* check = find_class(d_hash, name, dictionary);
860 if (check != NULL) {
861 // Klass is already loaded, so just use it
862 k = check;
863 CLEAR_PENDING_EXCEPTION;
864 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
865 }
866 }
867 }
868
869 // If everything was OK (no exceptions, no null return value), and
870 // class_loader is NOT the defining loader, do a little more bookkeeping.
871 if (!HAS_PENDING_EXCEPTION && k != NULL &&
872 k->class_loader() != class_loader()) {
873
874 check_constraints(d_hash, k, class_loader, false, THREAD);
875
876 // Need to check for a PENDING_EXCEPTION again; check_constraints
877 // can throw and doesn't use the CHECK macro.
878 if (!HAS_PENDING_EXCEPTION) {
879 { // Grabbing the Compile_lock prevents systemDictionary updates
880 // during compilations.
881 MutexLocker mu(Compile_lock, THREAD);
882 update_dictionary(d_hash, p_index, p_hash,
883 k, class_loader, THREAD);
884 }
885
886 if (JvmtiExport::should_post_class_load()) {
887 Thread *thread = THREAD;
888 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
889 JvmtiExport::post_class_load((JavaThread *) thread, k);
890 }
891 }
892 }
893 } // load_instance_class
894
895 if (load_instance_added == true) {
896 // clean up placeholder entries for LOAD_INSTANCE success or error
897 // This brackets the SystemDictionary updates for both defining
898 // and initiating loaders
899 MutexLocker mu(SystemDictionary_lock, THREAD);
900 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
901 SystemDictionary_lock->notify_all();
902 }
903 }
904
905 if (HAS_PENDING_EXCEPTION || k == NULL) {
906 return NULL;
907 }
908
909 post_class_load_event(&class_load_start_event, k, loader_data);
910
911 #ifdef ASSERT
912 {
913 ClassLoaderData* loader_data = k->class_loader_data();
914 MutexLocker mu(SystemDictionary_lock, THREAD);
915 Klass* kk = find_class(name, loader_data);
916 assert(kk == k, "should be present in dictionary");
917 }
918 #endif
919
920 // return if the protection domain in NULL
921 if (protection_domain() == NULL) return k;
922
923 // Check the protection domain has the right access
924 if (dictionary->is_valid_protection_domain(d_hash, name,
925 protection_domain)) {
926 return k;
927 }
928
929 // Verify protection domain. If it fails an exception is thrown
930 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
931
932 return k;
933 }
934
935
936 // This routine does not lock the system dictionary.
937 //
938 // Since readers don't hold a lock, we must make sure that system
939 // dictionary entries are only removed at a safepoint (when only one
940 // thread is running), and are added to in a safe way (all links must
941 // be updated in an MT-safe manner).
942 //
943 // Callers should be aware that an entry could be added just after
944 // _dictionary->bucket(index) is read here, so the caller will not see
945 // the new entry.
946
947 Klass* SystemDictionary::find(Symbol* class_name,
948 Handle class_loader,
949 Handle protection_domain,
950 TRAPS) {
951
952 // The result of this call should be consistent with the result
953 // of the call to resolve_instance_class_or_null().
954 // See evaluation 6790209 and 4474172 for more details.
955 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
956 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
957
958 if (loader_data == NULL) {
959 // If the ClassLoaderData has not been setup,
960 // then the class loader has no entries in the dictionary.
961 return NULL;
962 }
963
964 Dictionary* dictionary = loader_data->dictionary();
965 unsigned int d_hash = dictionary->compute_hash(class_name);
966 return dictionary->find(d_hash, class_name,
967 protection_domain);
968 }
969
970
971 // Look for a loaded instance or array klass by name. Do not do any loading.
972 // return NULL in case of error.
973 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
974 Handle class_loader,
975 Handle protection_domain,
976 TRAPS) {
977 Klass* k = NULL;
978 assert(class_name != NULL, "class name must be non NULL");
979
980 if (FieldType::is_array(class_name)) {
981 // The name refers to an array. Parse the name.
982 // dimension and object_key in FieldArrayInfo are assigned as a
983 // side-effect of this call
984 FieldArrayInfo fd;
985 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
986 if (t != T_OBJECT) {
987 k = Universe::typeArrayKlassObj(t);
988 } else {
989 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
990 }
991 if (k != NULL) {
992 k = k->array_klass_or_null(fd.dimension());
993 }
994 } else {
995 k = find(class_name, class_loader, protection_domain, THREAD);
996 }
997 return k;
998 }
999
1000 // Note: this method is much like resolve_from_stream, but
1001 // does not publish the classes via the SystemDictionary.
1002 // Handles unsafe_DefineAnonymousClass and redefineclasses
1003 // RedefinedClasses do not add to the class hierarchy
1004 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1005 Handle class_loader,
1006 Handle protection_domain,
1007 ClassFileStream* st,
1008 const InstanceKlass* host_klass,
1009 GrowableArray<Handle>* cp_patches,
1010 TRAPS) {
1011
1012 EventClassLoad class_load_start_event;
1013
1014 ClassLoaderData* loader_data;
1015 if (host_klass != NULL) {
1016 // Create a new CLD for anonymous class, that uses the same class loader
1017 // as the host_klass
1018 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1019 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1020 } else {
1021 loader_data = ClassLoaderData::class_loader_data(class_loader());
1022 }
1023
1024 assert(st != NULL, "invariant");
1025 assert(st->need_verify(), "invariant");
1026
1027 // Parse stream and create a klass.
1028 // Note that we do this even though this klass might
1029 // already be present in the SystemDictionary, otherwise we would not
1030 // throw potential ClassFormatErrors.
1031
1032 InstanceKlass* k = KlassFactory::create_from_stream(st,
1033 class_name,
1034 loader_data,
1035 protection_domain,
1036 host_klass,
1037 cp_patches,
1038 CHECK_NULL);
1039
1040 if (host_klass != NULL && k != NULL) {
1041 // If it's anonymous, initialize it now, since nobody else will.
1042
1043 {
1044 MutexLocker mu_r(Compile_lock, THREAD);
1045
1046 // Add to class hierarchy, initialize vtables, and do possible
1047 // deoptimizations.
1048 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1049
1050 // But, do not add to dictionary.
1051
1052 // compiled code dependencies need to be validated anyway
1053 notice_modification();
1054 }
1055
1056 // Rewrite and patch constant pool here.
1057 k->link_class(CHECK_NULL);
1058 if (cp_patches != NULL) {
1059 k->constants()->patch_resolved_references(cp_patches);
1060 }
1061 k->eager_initialize(CHECK_NULL);
1062
1063 // notify jvmti
1064 if (JvmtiExport::should_post_class_load()) {
1065 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1066 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1067 }
1068
1069 post_class_load_event(&class_load_start_event, k, loader_data);
1070 }
1071 assert(host_klass != NULL || NULL == cp_patches,
1072 "cp_patches only found with host_klass");
1073
1074 return k;
1075 }
1076
1077 // Add a klass to the system from a stream (called by jni_DefineClass and
1078 // JVM_DefineClass).
1079 // Note: class_name can be NULL. In that case we do not know the name of
1080 // the class until we have parsed the stream.
1081
1082 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1083 Handle class_loader,
1084 Handle protection_domain,
1085 ClassFileStream* st,
1086 TRAPS) {
1087 #if INCLUDE_CDS
1088 ResourceMark rm(THREAD);
1089 if (DumpSharedSpaces && !class_loader.is_null() &&
1090 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1091 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1092 // class, which is used by MethodHandles).
1093 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1094 }
1095 #endif
1096
1097 HandleMark hm(THREAD);
1098
1099 // Classloaders that support parallelism, e.g. bootstrap classloader,
1100 // or all classloaders with UnsyncloadClass do not acquire lock here
1101 bool DoObjectLock = true;
1102 if (is_parallelCapable(class_loader)) {
1103 DoObjectLock = false;
1104 }
1105
1106 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1107
1108 // Make sure we are synchronized on the class loader before we proceed
1109 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1110 check_loader_lock_contention(lockObject, THREAD);
1111 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1112
1113 assert(st != NULL, "invariant");
1114
1115 // Parse the stream and create a klass.
1116 // Note that we do this even though this klass might
1117 // already be present in the SystemDictionary, otherwise we would not
1118 // throw potential ClassFormatErrors.
1119 InstanceKlass* k = NULL;
1120
1121 #if INCLUDE_CDS
1122 if (!DumpSharedSpaces) {
1123 k = SystemDictionaryShared::lookup_from_stream(class_name,
1124 class_loader,
1125 protection_domain,
1126 st,
1127 CHECK_NULL);
1128 }
1129 #endif
1130
1131 if (k == NULL) {
1132 if (st->buffer() == NULL) {
1133 return NULL;
1134 }
1135 k = KlassFactory::create_from_stream(st,
1136 class_name,
1137 loader_data,
1138 protection_domain,
1139 NULL, // host_klass
1140 NULL, // cp_patches
1141 CHECK_NULL);
1142 }
1143
1144 assert(k != NULL, "no klass created");
1145 Symbol* h_name = k->name();
1146 assert(class_name == NULL || class_name == h_name, "name mismatch");
1147
1148 // Add class just loaded
1149 // If a class loader supports parallel classloading handle parallel define requests
1150 // find_or_define_instance_class may return a different InstanceKlass
1151 if (is_parallelCapable(class_loader)) {
1152 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1153 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1154 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1155 assert(defined_k != NULL, "Should have a klass if there's no exception");
1156 loader_data->add_to_deallocate_list(k);
1157 k = defined_k;
1158 }
1159 } else {
1160 define_instance_class(k, THREAD);
1161 }
1162
1163 // If defining the class throws an exception register 'k' for cleanup.
1164 if (HAS_PENDING_EXCEPTION) {
1165 assert(k != NULL, "Must have an instance klass here!");
1166 loader_data->add_to_deallocate_list(k);
1167 return NULL;
1168 }
1169
1170 // Make sure we have an entry in the SystemDictionary on success
1171 debug_only( {
1172 MutexLocker mu(SystemDictionary_lock, THREAD);
1173
1174 Klass* check = find_class(h_name, k->class_loader_data());
1175 assert(check == k, "should be present in the dictionary");
1176 } );
1177
1178 return k;
1179 }
1180
1181 #if INCLUDE_CDS
1182 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1183 int number_of_entries) {
1184 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1185 "bad shared dictionary size.");
1186 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1187 _shared_dictionary_size, t, number_of_entries);
1188 }
1189
1190
1191 // If there is a shared dictionary, then find the entry for the
1192 // given shared system class, if any.
1193
1194 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1195 if (shared_dictionary() != NULL) {
1196 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1197 int d_index = shared_dictionary()->hash_to_index(d_hash);
1198
1199 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1200 } else {
1201 return NULL;
1202 }
1203 }
1204
1205
1206 // Load a class from the shared spaces (found through the shared system
1207 // dictionary). Force the superclass and all interfaces to be loaded.
1208 // Update the class definition to include sibling classes and no
1209 // subclasses (yet). [Classes in the shared space are not part of the
1210 // object hierarchy until loaded.]
1211
1212 InstanceKlass* SystemDictionary::load_shared_class(
1213 Symbol* class_name, Handle class_loader, TRAPS) {
1214 InstanceKlass* ik = find_shared_class(class_name);
1215 // Make sure we only return the boot class for the NULL classloader.
1216 if (ik != NULL &&
1217 ik->is_shared_boot_class() && class_loader.is_null()) {
1218 Handle protection_domain;
1219 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1220 }
1221 return NULL;
1222 }
1223
1224 // Check if a shared class can be loaded by the specific classloader:
1225 //
1226 // NULL classloader:
1227 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1228 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1229 // be defined in an unnamed module.
1230 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1231 InstanceKlass* ik,
1232 Handle class_loader, TRAPS) {
1233 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1234 "Cannot use sharing if java.base is patched");
1235 ResourceMark rm;
1236 int path_index = ik->shared_classpath_index();
1237 ClassLoaderData* loader_data = class_loader_data(class_loader);
1238 if (path_index < 0) {
1239 // path_index < 0 indicates that the class is intended for a custom loader
1240 // and should not be loaded by boot/platform/app loaders
1241 if (loader_data->is_builtin_class_loader_data()) {
1242 return false;
1243 } else {
1244 return true;
1245 }
1246 }
1247 SharedClassPathEntry* ent =
1248 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1249 if (!Universe::is_module_initialized()) {
1250 assert(ent != NULL && ent->is_modules_image(),
1251 "Loading non-bootstrap classes before the module system is initialized");
1252 assert(class_loader.is_null(), "sanity");
1253 return true;
1254 }
1255 // Get the pkg_entry from the classloader
1256 TempNewSymbol pkg_name = NULL;
1257 PackageEntry* pkg_entry = NULL;
1258 ModuleEntry* mod_entry = NULL;
1259 const char* pkg_string = NULL;
1260 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1261 if (pkg_name != NULL) {
1262 pkg_string = pkg_name->as_C_string();
1263 if (loader_data != NULL) {
1264 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1265 }
1266 if (pkg_entry != NULL) {
1267 mod_entry = pkg_entry->module();
1268 }
1269 }
1270
1271 // If the archived class is from a module that has been patched at runtime,
1272 // the class cannot be loaded from the archive.
1273 if (mod_entry != NULL && mod_entry->is_patched()) {
1274 return false;
1275 }
1276
1277 if (class_loader.is_null()) {
1278 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1279 // The NULL classloader can load archived class originated from the
1280 // "modules" jimage and the -Xbootclasspath/a. For class from the
1281 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1282 // by the NULL classloader.
1283 if (mod_entry != NULL) {
1284 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1285 // ModuleEntry's location agrees with the archived class' origination.
1286 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1287 return true; // Module class from the "module" jimage
1288 }
1289 }
1290
1291 // If the archived class is not from the "module" jimage, the class can be
1292 // loaded by the NULL classloader if
1293 //
1294 // 1. the class is from the unamed package
1295 // 2. or, the class is not from a module defined in the NULL classloader
1296 // 3. or, the class is from an unamed module
1297 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1298 // the class is from the -Xbootclasspath/a
1299 if (pkg_string == NULL ||
1300 pkg_entry == NULL ||
1301 pkg_entry->in_unnamed_module()) {
1302 assert(mod_entry == NULL ||
1303 mod_entry == loader_data->unnamed_module(),
1304 "the unnamed module is not defined in the classloader");
1305 return true;
1306 }
1307 }
1308 return false;
1309 } else {
1310 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1311 ik, class_loader, pkg_string, pkg_name,
1312 pkg_entry, mod_entry, CHECK_(false));
1313 return res;
1314 }
1315 }
1316
1317 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1318 Handle class_loader,
1319 Handle protection_domain, TRAPS) {
1320
1321 if (ik != NULL) {
1322 Symbol* class_name = ik->name();
1323
1324 bool visible = is_shared_class_visible(
1325 class_name, ik, class_loader, CHECK_NULL);
1326 if (!visible) {
1327 return NULL;
1328 }
1329
1330 // Resolve the superclass and interfaces. They must be the same
1331 // as in dump time, because the layout of <ik> depends on
1332 // the specific layout of ik->super() and ik->local_interfaces().
1333 //
1334 // If unexpected superclass or interfaces are found, we cannot
1335 // load <ik> from the shared archive.
1336
1337 if (ik->super() != NULL) {
1338 Symbol* cn = ik->super()->name();
1339 Klass *s = resolve_super_or_fail(class_name, cn,
1340 class_loader, protection_domain, true, CHECK_NULL);
1341 if (s != ik->super()) {
1342 // The dynamically resolved super class is not the same as the one we used during dump time,
1343 // so we cannot use ik.
1344 return NULL;
1345 } else {
1346 assert(s->is_shared(), "must be");
1347 }
1348 }
1349
1350 Array<Klass*>* interfaces = ik->local_interfaces();
1351 int num_interfaces = interfaces->length();
1352 for (int index = 0; index < num_interfaces; index++) {
1353 Klass* k = interfaces->at(index);
1354 Symbol* name = k->name();
1355 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1356 if (k != i) {
1357 // The dynamically resolved interface class is not the same as the one we used during dump time,
1358 // so we cannot use ik.
1359 return NULL;
1360 } else {
1361 assert(i->is_shared(), "must be");
1362 }
1363 }
1364
1365 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1366 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1367 if (new_ik != NULL) {
1368 // The class is changed by CFLH. Return the new class. The shared class is
1369 // not used.
1370 return new_ik;
1371 }
1372
1373 // Adjust methods to recover missing data. They need addresses for
1374 // interpreter entry points and their default native method address
1375 // must be reset.
1376
1377 // Updating methods must be done under a lock so multiple
1378 // threads don't update these in parallel
1379 //
1380 // Shared classes are all currently loaded by either the bootstrap or
1381 // internal parallel class loaders, so this will never cause a deadlock
1382 // on a custom class loader lock.
1383
1384 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1385 {
1386 HandleMark hm(THREAD);
1387 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1388 check_loader_lock_contention(lockObject, THREAD);
1389 ObjectLocker ol(lockObject, THREAD, true);
1390 // prohibited package check assumes all classes loaded from archive call
1391 // restore_unshareable_info which calls ik->set_package()
1392 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1393 }
1394
1395 ik->print_class_load_logging(loader_data, NULL, NULL);
1396
1397 // For boot loader, ensure that GetSystemPackage knows that a class in this
1398 // package was loaded.
1399 if (class_loader.is_null()) {
1400 int path_index = ik->shared_classpath_index();
1401 ResourceMark rm;
1402 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1403 }
1404
1405 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1406 // Only dump the classes that can be stored into CDS archive
1407 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1408 ResourceMark rm(THREAD);
1409 classlist_file->print_cr("%s", ik->name()->as_C_string());
1410 classlist_file->flush();
1411 }
1412 }
1413
1414 // notify a class loaded from shared object
1415 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1416 }
1417
1418 ik->set_has_passed_fingerprint_check(false);
1419 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1420 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1421 uint64_t cds_fp = ik->get_stored_fingerprint();
1422 if (aot_fp != 0 && aot_fp == cds_fp) {
1423 // This class matches with a class saved in an AOT library
1424 ik->set_has_passed_fingerprint_check(true);
1425 } else {
1426 ResourceMark rm;
1427 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1428 }
1429 }
1430 return ik;
1431 }
1432
1433 void SystemDictionary::clear_invoke_method_table() {
1434 SymbolPropertyEntry* spe = NULL;
1435 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1436 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1437 while (p != NULL) {
1438 spe = p;
1439 p = p->next();
1440 _invoke_method_table->free_entry(spe);
1441 }
1442 }
1443 }
1444 #endif // INCLUDE_CDS
1445
1446 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1447
1448 if (class_loader.is_null()) {
1449 ResourceMark rm;
1450 PackageEntry* pkg_entry = NULL;
1451 bool search_only_bootloader_append = false;
1452 ClassLoaderData *loader_data = class_loader_data(class_loader);
1453
1454 // Find the package in the boot loader's package entry table.
1455 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1456 if (pkg_name != NULL) {
1457 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1458 }
1459
1460 // Prior to attempting to load the class, enforce the boot loader's
1461 // visibility boundaries.
1462 if (!Universe::is_module_initialized()) {
1463 // During bootstrapping, prior to module initialization, any
1464 // class attempting to be loaded must be checked against the
1465 // java.base packages in the boot loader's PackageEntryTable.
1466 // No class outside of java.base is allowed to be loaded during
1467 // this bootstrapping window.
1468 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1469 // Class is either in the unnamed package or in
1470 // a named package within the unnamed module. Either
1471 // case is outside of java.base, do not attempt to
1472 // load the class post java.base definition. If
1473 // java.base has not been defined, let the class load
1474 // and its package will be checked later by
1475 // ModuleEntryTable::verify_javabase_packages.
1476 if (ModuleEntryTable::javabase_defined()) {
1477 return NULL;
1478 }
1479 } else {
1480 // Check that the class' package is defined within java.base.
1481 ModuleEntry* mod_entry = pkg_entry->module();
1482 Symbol* mod_entry_name = mod_entry->name();
1483 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1484 return NULL;
1485 }
1486 }
1487 } else {
1488 // After the module system has been initialized, check if the class'
1489 // package is in a module defined to the boot loader.
1490 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1491 // Class is either in the unnamed package, in a named package
1492 // within a module not defined to the boot loader or in a
1493 // a named package within the unnamed module. In all cases,
1494 // limit visibility to search for the class only in the boot
1495 // loader's append path.
1496 search_only_bootloader_append = true;
1497 }
1498 }
1499
1500 // Prior to bootstrapping's module initialization, never load a class outside
1501 // of the boot loader's module path
1502 assert(Universe::is_module_initialized() ||
1503 !search_only_bootloader_append,
1504 "Attempt to load a class outside of boot loader's module path");
1505
1506 // Search the shared system dictionary for classes preloaded into the
1507 // shared spaces.
1508 InstanceKlass* k = NULL;
1509 {
1510 #if INCLUDE_CDS
1511 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1512 k = load_shared_class(class_name, class_loader, THREAD);
1513 #endif
1514 }
1515
1516 if (k == NULL) {
1517 // Use VM class loader
1518 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1519 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1520 }
1521
1522 // find_or_define_instance_class may return a different InstanceKlass
1523 if (k != NULL) {
1524 InstanceKlass* defined_k =
1525 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1526 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1527 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1528 assert(defined_k != NULL, "Should have a klass if there's no exception");
1529 loader_data->add_to_deallocate_list(k);
1530 k = defined_k;
1531 } else if (HAS_PENDING_EXCEPTION) {
1532 loader_data->add_to_deallocate_list(k);
1533 return NULL;
1534 }
1535 }
1536 return k;
1537 } else {
1538 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1539 ResourceMark rm(THREAD);
1540
1541 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1542 JavaThread* jt = (JavaThread*) THREAD;
1543
1544 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1545 ClassLoader::perf_app_classload_selftime(),
1546 ClassLoader::perf_app_classload_count(),
1547 jt->get_thread_stat()->perf_recursion_counts_addr(),
1548 jt->get_thread_stat()->perf_timers_addr(),
1549 PerfClassTraceTime::CLASS_LOAD);
1550
1551 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1552 // Translate to external class name format, i.e., convert '/' chars to '.'
1553 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1554
1555 JavaValue result(T_OBJECT);
1556
1557 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1558
1559 // Call public unsynchronized loadClass(String) directly for all class loaders
1560 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1561 // acquire a class-name based lock rather than the class loader object lock.
1562 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1563 // so the call to loadClassInternal() was not required.
1564 //
1565 // UnsyncloadClass flag means both call loadClass(String) and do
1566 // not acquire the class loader lock even for class loaders that are
1567 // not parallelCapable. This was a risky transitional
1568 // flag for diagnostic purposes only. It is risky to call
1569 // custom class loaders without synchronization.
1570 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1571 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1572 // Do NOT assume this will be supported in future releases.
1573 //
1574 // Added MustCallLoadClassInternal in case we discover in the field
1575 // a customer that counts on this call
1576 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1577 JavaCalls::call_special(&result,
1578 class_loader,
1579 spec_klass,
1580 vmSymbols::loadClassInternal_name(),
1581 vmSymbols::string_class_signature(),
1582 string,
1583 CHECK_NULL);
1584 } else {
1585 JavaCalls::call_virtual(&result,
1586 class_loader,
1587 spec_klass,
1588 vmSymbols::loadClass_name(),
1589 vmSymbols::string_class_signature(),
1590 string,
1591 CHECK_NULL);
1592 }
1593
1594 assert(result.get_type() == T_OBJECT, "just checking");
1595 oop obj = (oop) result.get_jobject();
1596
1597 // Primitive classes return null since forName() can not be
1598 // used to obtain any of the Class objects representing primitives or void
1599 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1600 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1601 // For user defined Java class loaders, check that the name returned is
1602 // the same as that requested. This check is done for the bootstrap
1603 // loader when parsing the class file.
1604 if (class_name == k->name()) {
1605 return k;
1606 }
1607 }
1608 // Class is not found or has the wrong name, return NULL
1609 return NULL;
1610 }
1611 }
1612
1613 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1614
1615 HandleMark hm(THREAD);
1616 ClassLoaderData* loader_data = k->class_loader_data();
1617 Handle class_loader_h(THREAD, loader_data->class_loader());
1618
1619 // for bootstrap and other parallel classloaders don't acquire lock,
1620 // use placeholder token
1621 // If a parallelCapable class loader calls define_instance_class instead of
1622 // find_or_define_instance_class to get here, we have a timing
1623 // hole with systemDictionary updates and check_constraints
1624 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1625 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1626 compute_loader_lock_object(class_loader_h, THREAD)),
1627 "define called without lock");
1628 }
1629
1630 // Check class-loading constraints. Throw exception if violation is detected.
1631 // Grabs and releases SystemDictionary_lock
1632 // The check_constraints/find_class call and update_dictionary sequence
1633 // must be "atomic" for a specific class/classloader pair so we never
1634 // define two different instanceKlasses for that class/classloader pair.
1635 // Existing classloaders will call define_instance_class with the
1636 // classloader lock held
1637 // Parallel classloaders will call find_or_define_instance_class
1638 // which will require a token to perform the define class
1639 Symbol* name_h = k->name();
1640 Dictionary* dictionary = loader_data->dictionary();
1641 unsigned int d_hash = dictionary->compute_hash(name_h);
1642 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1643
1644 // Register class just loaded with class loader (placed in Vector)
1645 // Note we do this before updating the dictionary, as this can
1646 // fail with an OutOfMemoryError (if it does, we will *not* put this
1647 // class in the dictionary and will not update the class hierarchy).
1648 // JVMTI FollowReferences needs to find the classes this way.
1649 if (k->class_loader() != NULL) {
1650 methodHandle m(THREAD, Universe::loader_addClass_method());
1651 JavaValue result(T_VOID);
1652 JavaCallArguments args(class_loader_h);
1653 args.push_oop(Handle(THREAD, k->java_mirror()));
1654 JavaCalls::call(&result, m, &args, CHECK);
1655 }
1656
1657 // Add the new class. We need recompile lock during update of CHA.
1658 {
1659 unsigned int p_hash = placeholders()->compute_hash(name_h);
1660 int p_index = placeholders()->hash_to_index(p_hash);
1661
1662 MutexLocker mu_r(Compile_lock, THREAD);
1663
1664 // Add to class hierarchy, initialize vtables, and do possible
1665 // deoptimizations.
1666 add_to_hierarchy(k, CHECK); // No exception, but can block
1667
1668 // Add to systemDictionary - so other classes can see it.
1669 // Grabs and releases SystemDictionary_lock
1670 update_dictionary(d_hash, p_index, p_hash,
1671 k, class_loader_h, THREAD);
1672 }
1673 k->eager_initialize(THREAD);
1674
1675 // notify jvmti
1676 if (JvmtiExport::should_post_class_load()) {
1677 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1678 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1679
1680 }
1681 class_define_event(k, loader_data);
1682 }
1683
1684 // Support parallel classloading
1685 // All parallel class loaders, including bootstrap classloader
1686 // lock a placeholder entry for this class/class_loader pair
1687 // to allow parallel defines of different classes for this class loader
1688 // With AllowParallelDefine flag==true, in case they do not synchronize around
1689 // FindLoadedClass/DefineClass, calls, we check for parallel
1690 // loading for them, wait if a defineClass is in progress
1691 // and return the initial requestor's results
1692 // This flag does not apply to the bootstrap classloader.
1693 // With AllowParallelDefine flag==false, call through to define_instance_class
1694 // which will throw LinkageError: duplicate class definition.
1695 // False is the requested default.
1696 // For better performance, the class loaders should synchronize
1697 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1698 // potentially waste time reading and parsing the bytestream.
1699 // Note: VM callers should ensure consistency of k/class_name,class_loader
1700 // Be careful when modifying this code: once you have run
1701 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1702 // you need to find_and_remove it before returning.
1703 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1704 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1705 InstanceKlass* k, TRAPS) {
1706
1707 Symbol* name_h = k->name(); // passed in class_name may be null
1708 ClassLoaderData* loader_data = class_loader_data(class_loader);
1709 Dictionary* dictionary = loader_data->dictionary();
1710
1711 unsigned int d_hash = dictionary->compute_hash(name_h);
1712
1713 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1714 unsigned int p_hash = placeholders()->compute_hash(name_h);
1715 int p_index = placeholders()->hash_to_index(p_hash);
1716 PlaceholderEntry* probe;
1717
1718 {
1719 MutexLocker mu(SystemDictionary_lock, THREAD);
1720 // First check if class already defined
1721 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1722 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1723 if (check != NULL) {
1724 return check;
1725 }
1726 }
1727
1728 // Acquire define token for this class/classloader
1729 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1730 // Wait if another thread defining in parallel
1731 // All threads wait - even those that will throw duplicate class: otherwise
1732 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1733 // if other thread has not finished updating dictionary
1734 while (probe->definer() != NULL) {
1735 SystemDictionary_lock->wait();
1736 }
1737 // Only special cases allow parallel defines and can use other thread's results
1738 // Other cases fall through, and may run into duplicate defines
1739 // caught by finding an entry in the SystemDictionary
1740 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1741 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1742 SystemDictionary_lock->notify_all();
1743 #ifdef ASSERT
1744 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1745 assert(check != NULL, "definer missed recording success");
1746 #endif
1747 return probe->instance_klass();
1748 } else {
1749 // This thread will define the class (even if earlier thread tried and had an error)
1750 probe->set_definer(THREAD);
1751 }
1752 }
1753
1754 define_instance_class(k, THREAD);
1755
1756 Handle linkage_exception = Handle(); // null handle
1757
1758 // definer must notify any waiting threads
1759 {
1760 MutexLocker mu(SystemDictionary_lock, THREAD);
1761 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1762 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1763 if (probe != NULL) {
1764 if (HAS_PENDING_EXCEPTION) {
1765 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1766 CLEAR_PENDING_EXCEPTION;
1767 } else {
1768 probe->set_instance_klass(k);
1769 }
1770 probe->set_definer(NULL);
1771 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1772 SystemDictionary_lock->notify_all();
1773 }
1774 }
1775
1776 // Can't throw exception while holding lock due to rank ordering
1777 if (linkage_exception() != NULL) {
1778 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1779 }
1780
1781 return k;
1782 }
1783
1784 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1785 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1786 if (class_loader.is_null()) {
1787 return Handle(THREAD, _system_loader_lock_obj);
1788 } else {
1789 return class_loader;
1790 }
1791 }
1792
1793 // This method is added to check how often we have to wait to grab loader
1794 // lock. The results are being recorded in the performance counters defined in
1795 // ClassLoader::_sync_systemLoaderLockContentionRate and
1796 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1797 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1798 if (!UsePerfData) {
1799 return;
1800 }
1801
1802 assert(!loader_lock.is_null(), "NULL lock object");
1803
1804 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1805 == ObjectSynchronizer::owner_other) {
1806 // contention will likely happen, so increment the corresponding
1807 // contention counter.
1808 if (loader_lock() == _system_loader_lock_obj) {
1809 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1810 } else {
1811 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1812 }
1813 }
1814 }
1815
1816 // ----------------------------------------------------------------------------
1817 // Lookup
1818
1819 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1820 Symbol* class_name,
1821 Dictionary* dictionary) {
1822 assert_locked_or_safepoint(SystemDictionary_lock);
1823 int index = dictionary->hash_to_index(hash);
1824 return dictionary->find_class(index, hash, class_name);
1825 }
1826
1827
1828 // Basic find on classes in the midst of being loaded
1829 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1830 ClassLoaderData* loader_data) {
1831 assert_locked_or_safepoint(SystemDictionary_lock);
1832 unsigned int p_hash = placeholders()->compute_hash(class_name);
1833 int p_index = placeholders()->hash_to_index(p_hash);
1834 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1835 }
1836
1837
1838 // Used for assertions and verification only
1839 // Precalculating the hash and index is an optimization because there are many lookups
1840 // before adding the class.
1841 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1842 assert_locked_or_safepoint(SystemDictionary_lock);
1843 #ifndef ASSERT
1844 guarantee(VerifyBeforeGC ||
1845 VerifyDuringGC ||
1846 VerifyBeforeExit ||
1847 VerifyDuringStartup ||
1848 VerifyAfterGC, "too expensive");
1849 #endif
1850
1851 Dictionary* dictionary = loader_data->dictionary();
1852 unsigned int d_hash = dictionary->compute_hash(class_name);
1853 return find_class(d_hash, class_name, dictionary);
1854 }
1855
1856
1857 // ----------------------------------------------------------------------------
1858 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1859 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1860 // before a new class is used.
1861
1862 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1863 assert(k != NULL, "just checking");
1864 assert_locked_or_safepoint(Compile_lock);
1865
1866 // Link into hierachy. Make sure the vtables are initialized before linking into
1867 k->append_to_sibling_list(); // add to superklass/sibling list
1868 k->process_interfaces(THREAD); // handle all "implements" declarations
1869 k->set_init_state(InstanceKlass::loaded);
1870 // Now flush all code that depended on old class hierarchy.
1871 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1872 // Also, first reinitialize vtable because it may have gotten out of synch
1873 // while the new class wasn't connected to the class hierarchy.
1874 CodeCache::flush_dependents_on(k);
1875 }
1876
1877 // ----------------------------------------------------------------------------
1878 // GC support
1879
1880 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1881 roots_oops_do(blk, NULL);
1882 }
1883
1884
1885 #ifdef ASSERT
1886 class VerifySDReachableAndLiveClosure : public OopClosure {
1887 private:
1888 BoolObjectClosure* _is_alive;
1889
1890 template <class T> void do_oop_work(T* p) {
1891 oop obj = oopDesc::load_decode_heap_oop(p);
1892 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1893 }
1894
1895 public:
1896 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1897
1898 virtual void do_oop(oop* p) { do_oop_work(p); }
1899 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1900 };
1901 #endif
1902
1903 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1904 // Note: anonymous classes are not in the SD.
1905 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1906 GCTimer* gc_timer,
1907 bool do_cleaning) {
1908
1909
1910 bool unloading_occurred;
1911 {
1912 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1913
1914 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1915 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1916 do_cleaning);
1917 }
1918
1919 if (unloading_occurred) {
1920 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1921 constraints()->purge_loader_constraints();
1922 resolution_errors()->purge_resolution_errors();
1923 }
1924
1925 {
1926 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1927 // Oops referenced by the protection domain cache table may get unreachable independently
1928 // of the class loader (eg. cached protection domain oops). So we need to
1929 // explicitly unlink them here.
1930 _pd_cache_table->unlink(is_alive);
1931
1932 #ifdef ASSERT
1933 VerifySDReachableAndLiveClosure cl(is_alive);
1934 _pd_cache_table->oops_do(&cl);
1935 #endif
1936 }
1937
1938 if (do_cleaning) {
1939 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1940 ResolvedMethodTable::unlink(is_alive);
1941 }
1942
1943 return unloading_occurred;
1944 }
1945
1946 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1947 strong->do_oop(&_java_system_loader);
1948 strong->do_oop(&_java_platform_loader);
1949 strong->do_oop(&_system_loader_lock_obj);
1950 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1951
1952 // Do strong roots marking if the closures are the same.
1953 if (strong == weak || !ClassUnloading) {
1954 // Only the protection domain oops contain references into the heap. Iterate
1955 // over all of them.
1956 _pd_cache_table->oops_do(strong);
1957 } else {
1958 if (weak != NULL) {
1959 _pd_cache_table->oops_do(weak);
1960 }
1961 }
1962
1963 // Visit extra methods
1964 invoke_method_table()->oops_do(strong);
1965
1966 if (weak != NULL) {
1967 ResolvedMethodTable::oops_do(weak);
1968 }
1969 }
1970
1971 void SystemDictionary::oops_do(OopClosure* f) {
1972 f->do_oop(&_java_system_loader);
1973 f->do_oop(&_java_platform_loader);
1974 f->do_oop(&_system_loader_lock_obj);
1975 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1976
1977 // Only the protection domain oops contain references into the heap. Iterate
1978 // over all of them.
1979 _pd_cache_table->oops_do(f);
1980
1981 // Visit extra methods
1982 invoke_method_table()->oops_do(f);
1983
1984 ResolvedMethodTable::oops_do(f);
1985 }
1986
1987 // CDS: scan and relocate all classes in the system dictionary.
1988 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1989 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1990 }
1991
1992 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1993 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1994 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1995 it->push(well_known_klass_addr((WKID)id));
1996 }
1997 }
1998
1999 void SystemDictionary::methods_do(void f(Method*)) {
2000 // Walk methods in loaded classes
2001 ClassLoaderDataGraph::methods_do(f);
2002 // Walk method handle intrinsics
2003 invoke_method_table()->methods_do(f);
2004 }
2005
2006 class RemoveClassesClosure : public CLDClosure {
2007 public:
2008 void do_cld(ClassLoaderData* cld) {
2009 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2010 cld->dictionary()->remove_classes_in_error_state();
2011 }
2012 }
2013 };
2014
2015 void SystemDictionary::remove_classes_in_error_state() {
2016 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
2017 RemoveClassesClosure rcc;
2018 ClassLoaderDataGraph::cld_do(&rcc);
2019 }
2020
2021 // ----------------------------------------------------------------------------
2022 // Lazily load klasses
2023
2024 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2025 // if multiple threads calling this function, only one thread will load
2026 // the class. The other threads will find the loaded version once the
2027 // class is loaded.
2028 Klass* aos = _abstract_ownable_synchronizer_klass;
2029 if (aos == NULL) {
2030 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2031 // Force a fence to prevent any read before the write completes
2032 OrderAccess::fence();
2033 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2034 }
2035 }
2036
2037 // ----------------------------------------------------------------------------
2038 // Initialization
2039
2040 void SystemDictionary::initialize(TRAPS) {
2041 // Allocate arrays
2042 _placeholders = new PlaceholderTable(_placeholder_table_size);
2043 _number_of_modifications = 0;
2044 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2045 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2046 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2047 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2048
2049 // Allocate private object used as system class loader lock
2050 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2051 // Initialize basic classes
2052 initialize_preloaded_classes(CHECK);
2053 }
2054
2055 // Compact table of directions on the initialization of klasses:
2056 static const short wk_init_info[] = {
2057 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2058 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2059 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2060 | (int)SystemDictionary::option ),
2061 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2062 #undef WK_KLASS_INIT_INFO
2063 0
2064 };
2065
2066 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2067 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2068 int info = wk_init_info[id - FIRST_WKID];
2069 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2070 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2071 InstanceKlass** klassp = &_well_known_klasses[id];
2072
2073 bool must_load;
2074 #if INCLUDE_JVMCI
2075 if (EnableJVMCI) {
2076 // If JVMCI is enabled we require its classes to be found.
2077 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2078 } else
2079 #endif
2080 {
2081 must_load = (init_opt < SystemDictionary::Opt);
2082 }
2083
2084 if ((*klassp) == NULL) {
2085 Klass* k;
2086 if (must_load) {
2087 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2088 } else {
2089 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2090 }
2091 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2092 }
2093 return ((*klassp) != NULL);
2094 }
2095
2096 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2097 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2098 for (int id = (int)start_id; id < (int)limit_id; id++) {
2099 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2100 int info = wk_init_info[id - FIRST_WKID];
2101 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2102 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2103
2104 initialize_wk_klass((WKID)id, opt, CHECK);
2105 }
2106
2107 // move the starting value forward to the limit:
2108 start_id = limit_id;
2109 }
2110
2111 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2112 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2113
2114 // Create the ModuleEntry for java.base. This call needs to be done here,
2115 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2116 ClassLoader::classLoader_init2(CHECK);
2117
2118 // Preload commonly used klasses
2119 WKID scan = FIRST_WKID;
2120 // first do Object, then String, Class
2121 #if INCLUDE_CDS
2122 if (UseSharedSpaces) {
2123 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2124 // Initialize the constant pool for the Object_class
2125 Object_klass()->constants()->restore_unshareable_info(CHECK);
2126 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2127 } else
2128 #endif
2129 {
2130 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2131 }
2132
2133 // Calculate offsets for String and Class classes since they are loaded and
2134 // can be used after this point.
2135 java_lang_String::compute_offsets();
2136 java_lang_Class::compute_offsets();
2137
2138 // Fixup mirrors for classes loaded before java.lang.Class.
2139 // These calls iterate over the objects currently in the perm gen
2140 // so calling them at this point is matters (not before when there
2141 // are fewer objects and not later after there are more objects
2142 // in the perm gen.
2143 Universe::initialize_basic_type_mirrors(CHECK);
2144 Universe::fixup_mirrors(CHECK);
2145
2146 // do a bunch more:
2147 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2148
2149 // Preload ref klasses and set reference types
2150 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2151 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2152
2153 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2154 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2155 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2156 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2157 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2158
2159 // JSR 292 classes
2160 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2161 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2162 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2163 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2164 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2165
2166 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2167 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2168 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2169 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2170 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2171 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2172 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2173 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2174 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2175 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2176
2177 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2178 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2179 _has_loadClassInternal = (method != NULL);
2180 }
2181 { // Compute whether we should use checkPackageAccess or NOT
2182 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2183 _has_checkPackageAccess = (method != NULL);
2184 }
2185 }
2186
2187 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2188 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2189 BasicType SystemDictionary::box_klass_type(Klass* k) {
2190 assert(k != NULL, "");
2191 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2192 if (_box_klasses[i] == k)
2193 return (BasicType)i;
2194 }
2195 return T_OBJECT;
2196 }
2197
2198 // Constraints on class loaders. The details of the algorithm can be
2199 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2200 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2201 // that the dictionary needs to maintain a set of contraints that
2202 // must be satisfied by all classes in the dictionary.
2203 // if defining is true, then LinkageError if already in dictionary
2204 // if initiating loader, then ok if InstanceKlass matches existing entry
2205
2206 void SystemDictionary::check_constraints(unsigned int d_hash,
2207 InstanceKlass* k,
2208 Handle class_loader, bool defining,
2209 TRAPS) {
2210 const char *linkage_error1 = NULL;
2211 const char *linkage_error2 = NULL;
2212 {
2213 Symbol* name = k->name();
2214 ClassLoaderData *loader_data = class_loader_data(class_loader);
2215
2216 MutexLocker mu(SystemDictionary_lock, THREAD);
2217
2218 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2219 if (check != NULL) {
2220 // if different InstanceKlass - duplicate class definition,
2221 // else - ok, class loaded by a different thread in parallel,
2222 // we should only have found it if it was done loading and ok to use
2223 // dictionary only holds instance classes, placeholders
2224 // also holds array classes
2225
2226 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2227 if ((defining == true) || (k != check)) {
2228 linkage_error1 = "loader (instance of ";
2229 linkage_error2 = "): attempted duplicate class definition for name: \"";
2230 } else {
2231 return;
2232 }
2233 }
2234
2235 #ifdef ASSERT
2236 Symbol* ph_check = find_placeholder(name, loader_data);
2237 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2238 #endif
2239
2240 if (linkage_error1 == NULL) {
2241 if (constraints()->check_or_update(k, class_loader, name) == false) {
2242 linkage_error1 = "loader constraint violation: loader (instance of ";
2243 linkage_error2 = ") previously initiated loading for a different type with name \"";
2244 }
2245 }
2246 }
2247
2248 // Throw error now if needed (cannot throw while holding
2249 // SystemDictionary_lock because of rank ordering)
2250
2251 if (linkage_error1) {
2252 ResourceMark rm(THREAD);
2253 const char* class_loader_name = loader_name(class_loader());
2254 char* type_name = k->name()->as_C_string();
2255 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2256 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2257 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2258 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2259 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2260 }
2261 }
2262
2263
2264 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2265 // have been called.
2266 void SystemDictionary::update_dictionary(unsigned int d_hash,
2267 int p_index, unsigned int p_hash,
2268 InstanceKlass* k,
2269 Handle class_loader,
2270 TRAPS) {
2271 // Compile_lock prevents systemDictionary updates during compilations
2272 assert_locked_or_safepoint(Compile_lock);
2273 Symbol* name = k->name();
2274 ClassLoaderData *loader_data = class_loader_data(class_loader);
2275
2276 {
2277 MutexLocker mu1(SystemDictionary_lock, THREAD);
2278
2279 // See whether biased locking is enabled and if so set it for this
2280 // klass.
2281 // Note that this must be done past the last potential blocking
2282 // point / safepoint. We enable biased locking lazily using a
2283 // VM_Operation to iterate the SystemDictionary and installing the
2284 // biasable mark word into each InstanceKlass's prototype header.
2285 // To avoid race conditions where we accidentally miss enabling the
2286 // optimization for one class in the process of being added to the
2287 // dictionary, we must not safepoint after the test of
2288 // BiasedLocking::enabled().
2289 if (UseBiasedLocking && BiasedLocking::enabled()) {
2290 // Set biased locking bit for all loaded classes; it will be
2291 // cleared if revocation occurs too often for this type
2292 // NOTE that we must only do this when the class is initally
2293 // defined, not each time it is referenced from a new class loader
2294 if (k->class_loader() == class_loader()) {
2295 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2296 }
2297 }
2298
2299 // Make a new dictionary entry.
2300 Dictionary* dictionary = loader_data->dictionary();
2301 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2302 if (sd_check == NULL) {
2303 dictionary->add_klass(d_hash, name, k);
2304 notice_modification();
2305 }
2306 #ifdef ASSERT
2307 sd_check = find_class(d_hash, name, dictionary);
2308 assert (sd_check != NULL, "should have entry in dictionary");
2309 // Note: there may be a placeholder entry: for circularity testing
2310 // or for parallel defines
2311 #endif
2312 SystemDictionary_lock->notify_all();
2313 }
2314 }
2315
2316
2317 // Try to find a class name using the loader constraints. The
2318 // loader constraints might know about a class that isn't fully loaded
2319 // yet and these will be ignored.
2320 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2321 Symbol* class_name, Handle class_loader, TRAPS) {
2322
2323 // First see if it has been loaded directly.
2324 // Force the protection domain to be null. (This removes protection checks.)
2325 Handle no_protection_domain;
2326 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2327 no_protection_domain, CHECK_NULL);
2328 if (klass != NULL)
2329 return klass;
2330
2331 // Now look to see if it has been loaded elsewhere, and is subject to
2332 // a loader constraint that would require this loader to return the
2333 // klass that is already loaded.
2334 if (FieldType::is_array(class_name)) {
2335 // For array classes, their Klass*s are not kept in the
2336 // constraint table. The element Klass*s are.
2337 FieldArrayInfo fd;
2338 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2339 if (t != T_OBJECT) {
2340 klass = Universe::typeArrayKlassObj(t);
2341 } else {
2342 MutexLocker mu(SystemDictionary_lock, THREAD);
2343 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2344 }
2345 // If element class already loaded, allocate array klass
2346 if (klass != NULL) {
2347 klass = klass->array_klass_or_null(fd.dimension());
2348 }
2349 } else {
2350 MutexLocker mu(SystemDictionary_lock, THREAD);
2351 // Non-array classes are easy: simply check the constraint table.
2352 klass = constraints()->find_constrained_klass(class_name, class_loader);
2353 }
2354
2355 return klass;
2356 }
2357
2358
2359 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2360 Handle class_loader1,
2361 Handle class_loader2,
2362 Thread* THREAD) {
2363 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2364 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2365
2366 Symbol* constraint_name = NULL;
2367 if (!FieldType::is_array(class_name)) {
2368 constraint_name = class_name;
2369 } else {
2370 // For array classes, their Klass*s are not kept in the
2371 // constraint table. The element classes are.
2372 FieldArrayInfo fd;
2373 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2374 // primitive types always pass
2375 if (t != T_OBJECT) {
2376 return true;
2377 } else {
2378 constraint_name = fd.object_key();
2379 }
2380 }
2381
2382 Dictionary* dictionary1 = loader_data1->dictionary();
2383 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2384
2385 Dictionary* dictionary2 = loader_data2->dictionary();
2386 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2387
2388 {
2389 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2390 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2391 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2392 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2393 klass2, class_loader2);
2394 }
2395 }
2396
2397 // Add entry to resolution error table to record the error when the first
2398 // attempt to resolve a reference to a class has failed.
2399 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2400 Symbol* error, Symbol* message) {
2401 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2402 int index = resolution_errors()->hash_to_index(hash);
2403 {
2404 MutexLocker ml(SystemDictionary_lock, Thread::current());
2405 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2406 }
2407 }
2408
2409 // Delete a resolution error for RedefineClasses for a constant pool is going away
2410 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2411 resolution_errors()->delete_entry(pool);
2412 }
2413
2414 // Lookup resolution error table. Returns error if found, otherwise NULL.
2415 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2416 Symbol** message) {
2417 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2418 int index = resolution_errors()->hash_to_index(hash);
2419 {
2420 MutexLocker ml(SystemDictionary_lock, Thread::current());
2421 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2422 if (entry != NULL) {
2423 *message = entry->message();
2424 return entry->error();
2425 } else {
2426 return NULL;
2427 }
2428 }
2429 }
2430
2431
2432 // Signature constraints ensure that callers and callees agree about
2433 // the meaning of type names in their signatures. This routine is the
2434 // intake for constraints. It collects them from several places:
2435 //
2436 // * LinkResolver::resolve_method (if check_access is true) requires
2437 // that the resolving class (the caller) and the defining class of
2438 // the resolved method (the callee) agree on each type in the
2439 // method's signature.
2440 //
2441 // * LinkResolver::resolve_interface_method performs exactly the same
2442 // checks.
2443 //
2444 // * LinkResolver::resolve_field requires that the constant pool
2445 // attempting to link to a field agree with the field's defining
2446 // class about the type of the field signature.
2447 //
2448 // * klassVtable::initialize_vtable requires that, when a class
2449 // overrides a vtable entry allocated by a superclass, that the
2450 // overriding method (i.e., the callee) agree with the superclass
2451 // on each type in the method's signature.
2452 //
2453 // * klassItable::initialize_itable requires that, when a class fills
2454 // in its itables, for each non-abstract method installed in an
2455 // itable, the method (i.e., the callee) agree with the interface
2456 // on each type in the method's signature.
2457 //
2458 // All those methods have a boolean (check_access, checkconstraints)
2459 // which turns off the checks. This is used from specialized contexts
2460 // such as bootstrapping, dumping, and debugging.
2461 //
2462 // No direct constraint is placed between the class and its
2463 // supertypes. Constraints are only placed along linked relations
2464 // between callers and callees. When a method overrides or implements
2465 // an abstract method in a supertype (superclass or interface), the
2466 // constraints are placed as if the supertype were the caller to the
2467 // overriding method. (This works well, since callers to the
2468 // supertype have already established agreement between themselves and
2469 // the supertype.) As a result of all this, a class can disagree with
2470 // its supertype about the meaning of a type name, as long as that
2471 // class neither calls a relevant method of the supertype, nor is
2472 // called (perhaps via an override) from the supertype.
2473 //
2474 //
2475 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2476 //
2477 // Make sure all class components (including arrays) in the given
2478 // signature will be resolved to the same class in both loaders.
2479 // Returns the name of the type that failed a loader constraint check, or
2480 // NULL if no constraint failed. No exception except OOME is thrown.
2481 // Arrays are not added to the loader constraint table, their elements are.
2482 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2483 Handle loader1, Handle loader2,
2484 bool is_method, TRAPS) {
2485 // Nothing to do if loaders are the same.
2486 if (loader1() == loader2()) {
2487 return NULL;
2488 }
2489
2490 SignatureStream sig_strm(signature, is_method);
2491 while (!sig_strm.is_done()) {
2492 if (sig_strm.is_object()) {
2493 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2494 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2495 return sig;
2496 }
2497 }
2498 sig_strm.next();
2499 }
2500 return NULL;
2501 }
2502
2503
2504 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2505 Symbol* signature,
2506 TRAPS) {
2507 methodHandle empty;
2508 assert(MethodHandles::is_signature_polymorphic(iid) &&
2509 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2510 iid != vmIntrinsics::_invokeGeneric,
2511 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2512
2513 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2514 int index = invoke_method_table()->hash_to_index(hash);
2515 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2516 methodHandle m;
2517 if (spe == NULL || spe->method() == NULL) {
2518 spe = NULL;
2519 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2520 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2521 if (!Arguments::is_interpreter_only()) {
2522 // Generate a compiled form of the MH intrinsic.
2523 AdapterHandlerLibrary::create_native_wrapper(m);
2524 // Check if have the compiled code.
2525 if (!m->has_compiled_code()) {
2526 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2527 "Out of space in CodeCache for method handle intrinsic", empty);
2528 }
2529 }
2530 // Now grab the lock. We might have to throw away the new method,
2531 // if a racing thread has managed to install one at the same time.
2532 {
2533 MutexLocker ml(SystemDictionary_lock, THREAD);
2534 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2535 if (spe == NULL)
2536 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2537 if (spe->method() == NULL)
2538 spe->set_method(m());
2539 }
2540 }
2541
2542 assert(spe != NULL && spe->method() != NULL, "");
2543 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2544 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2545 "MH intrinsic invariant");
2546 return spe->method();
2547 }
2548
2549 // Helper for unpacking the return value from linkMethod and linkCallSite.
2550 static methodHandle unpack_method_and_appendix(Handle mname,
2551 Klass* accessing_klass,
2552 objArrayHandle appendix_box,
2553 Handle* appendix_result,
2554 TRAPS) {
2555 methodHandle empty;
2556 if (mname.not_null()) {
2557 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2558 if (m != NULL) {
2559 oop appendix = appendix_box->obj_at(0);
2560 if (TraceMethodHandles) {
2561 #ifndef PRODUCT
2562 ttyLocker ttyl;
2563 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2564 m->print();
2565 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2566 tty->cr();
2567 #endif //PRODUCT
2568 }
2569 (*appendix_result) = Handle(THREAD, appendix);
2570 // the target is stored in the cpCache and if a reference to this
2571 // MethodName is dropped we need a way to make sure the
2572 // class_loader containing this method is kept alive.
2573 // FIXME: the appendix might also preserve this dependency.
2574 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2575 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2576 return methodHandle(THREAD, m);
2577 }
2578 }
2579 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2580 return empty;
2581 }
2582
2583 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2584 Symbol* name,
2585 Symbol* signature,
2586 Klass* accessing_klass,
2587 Handle *appendix_result,
2588 Handle *method_type_result,
2589 TRAPS) {
2590 methodHandle empty;
2591 assert(THREAD->can_call_java() ,"");
2592 Handle method_type =
2593 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2594
2595 int ref_kind = JVM_REF_invokeVirtual;
2596 oop name_oop = StringTable::intern(name, CHECK_(empty));
2597 Handle name_str (THREAD, name_oop);
2598 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2599 assert(appendix_box->obj_at(0) == NULL, "");
2600
2601 // This should not happen. JDK code should take care of that.
2602 if (accessing_klass == NULL || method_type.is_null()) {
2603 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2604 }
2605
2606 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2607 JavaCallArguments args;
2608 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2609 args.push_int(ref_kind);
2610 args.push_oop(Handle(THREAD, klass->java_mirror()));
2611 args.push_oop(name_str);
2612 args.push_oop(method_type);
2613 args.push_oop(appendix_box);
2614 JavaValue result(T_OBJECT);
2615 JavaCalls::call_static(&result,
2616 SystemDictionary::MethodHandleNatives_klass(),
2617 vmSymbols::linkMethod_name(),
2618 vmSymbols::linkMethod_signature(),
2619 &args, CHECK_(empty));
2620 Handle mname(THREAD, (oop) result.get_jobject());
2621 (*method_type_result) = method_type;
2622 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2623 }
2624
2625 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2626 // We must ensure that all class loaders everywhere will reach this class, for any client.
2627 // This is a safe bet for public classes in java.lang, such as Object and String.
2628 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2629 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2630 static bool is_always_visible_class(oop mirror) {
2631 Klass* klass = java_lang_Class::as_Klass(mirror);
2632 if (klass->is_objArray_klass()) {
2633 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2634 }
2635 if (klass->is_typeArray_klass()) {
2636 return true; // primitive array
2637 }
2638 assert(klass->is_instance_klass(), "%s", klass->external_name());
2639 return klass->is_public() &&
2640 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2641 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2642 }
2643
2644 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2645 // signature, as interpreted relative to the given class loader.
2646 // Because of class loader constraints, all method handle usage must be
2647 // consistent with this loader.
2648 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2649 Klass* accessing_klass,
2650 TRAPS) {
2651 Handle empty;
2652 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2653 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2654 int index = invoke_method_table()->hash_to_index(hash);
2655 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2656 if (spe != NULL && spe->method_type() != NULL) {
2657 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2658 return Handle(THREAD, spe->method_type());
2659 } else if (!THREAD->can_call_java()) {
2660 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2661 return Handle(); // do not attempt from within compiler, unless it was cached
2662 }
2663
2664 Handle class_loader, protection_domain;
2665 if (accessing_klass != NULL) {
2666 class_loader = Handle(THREAD, accessing_klass->class_loader());
2667 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2668 }
2669 bool can_be_cached = true;
2670 int npts = ArgumentCount(signature).size();
2671 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2672 int arg = 0;
2673 Handle rt; // the return type from the signature
2674 ResourceMark rm(THREAD);
2675 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2676 oop mirror = NULL;
2677 if (can_be_cached) {
2678 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2679 mirror = ss.as_java_mirror(Handle(), Handle(),
2680 SignatureStream::ReturnNull, CHECK_(empty));
2681 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2682 // Fall back to accessing_klass context.
2683 can_be_cached = false;
2684 }
2685 }
2686 if (!can_be_cached) {
2687 // Resolve, throwing a real error if it doesn't work.
2688 mirror = ss.as_java_mirror(class_loader, protection_domain,
2689 SignatureStream::NCDFError, CHECK_(empty));
2690 }
2691 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2692 if (ss.at_return_type())
2693 rt = Handle(THREAD, mirror);
2694 else
2695 pts->obj_at_put(arg++, mirror);
2696
2697 // Check accessibility.
2698 if (ss.is_object() && accessing_klass != NULL) {
2699 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2700 mirror = NULL; // safety
2701 // Emulate ConstantPool::verify_constant_pool_resolve.
2702 if (sel_klass->is_objArray_klass())
2703 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2704 if (sel_klass->is_instance_klass()) {
2705 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2706 }
2707 }
2708 }
2709 assert(arg == npts, "");
2710
2711 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2712 JavaCallArguments args(Handle(THREAD, rt()));
2713 args.push_oop(pts);
2714 JavaValue result(T_OBJECT);
2715 JavaCalls::call_static(&result,
2716 SystemDictionary::MethodHandleNatives_klass(),
2717 vmSymbols::findMethodHandleType_name(),
2718 vmSymbols::findMethodHandleType_signature(),
2719 &args, CHECK_(empty));
2720 Handle method_type(THREAD, (oop) result.get_jobject());
2721
2722 if (can_be_cached) {
2723 // We can cache this MethodType inside the JVM.
2724 MutexLocker ml(SystemDictionary_lock, THREAD);
2725 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2726 if (spe == NULL)
2727 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2728 if (spe->method_type() == NULL) {
2729 spe->set_method_type(method_type());
2730 }
2731 }
2732
2733 // report back to the caller with the MethodType
2734 return method_type;
2735 }
2736
2737 // Ask Java code to find or construct a method handle constant.
2738 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2739 int ref_kind, //e.g., JVM_REF_invokeVirtual
2740 Klass* callee,
2741 Symbol* name_sym,
2742 Symbol* signature,
2743 TRAPS) {
2744 Handle empty;
2745 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2746 Handle type;
2747 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2748 type = find_method_handle_type(signature, caller, CHECK_(empty));
2749 } else if (caller == NULL) {
2750 // This should not happen. JDK code should take care of that.
2751 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2752 } else {
2753 ResourceMark rm(THREAD);
2754 SignatureStream ss(signature, false);
2755 if (!ss.is_done()) {
2756 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2757 Handle(THREAD, caller->protection_domain()),
2758 SignatureStream::NCDFError, CHECK_(empty));
2759 type = Handle(THREAD, mirror);
2760 ss.next();
2761 if (!ss.is_done()) type = Handle(); // error!
2762 }
2763 }
2764 if (type.is_null()) {
2765 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2766 }
2767
2768 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2769 JavaCallArguments args;
2770 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2771 args.push_int(ref_kind);
2772 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2773 args.push_oop(name);
2774 args.push_oop(type);
2775 JavaValue result(T_OBJECT);
2776 JavaCalls::call_static(&result,
2777 SystemDictionary::MethodHandleNatives_klass(),
2778 vmSymbols::linkMethodHandleConstant_name(),
2779 vmSymbols::linkMethodHandleConstant_signature(),
2780 &args, CHECK_(empty));
2781 return Handle(THREAD, (oop) result.get_jobject());
2782 }
2783
2784 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2785 // name and signature, as interpreted relative to the given class loader.
2786 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2787 Handle bootstrap_specifier,
2788 Symbol* name,
2789 Symbol* type,
2790 Handle *appendix_result,
2791 Handle *method_type_result,
2792 TRAPS) {
2793 methodHandle empty;
2794 Handle bsm, info;
2795 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2796 bsm = bootstrap_specifier;
2797 } else {
2798 assert(bootstrap_specifier->is_objArray(), "");
2799 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2800 int len = args->length();
2801 assert(len >= 1, "");
2802 bsm = Handle(THREAD, args->obj_at(0));
2803 if (len > 1) {
2804 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2805 for (int i = 1; i < len; i++)
2806 args1->obj_at_put(i-1, args->obj_at(i));
2807 info = Handle(THREAD, args1);
2808 }
2809 }
2810 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2811 "caller must supply a valid BSM");
2812
2813 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2814 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2815
2816 // This should not happen. JDK code should take care of that.
2817 if (caller == NULL || method_type.is_null()) {
2818 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2819 }
2820
2821 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2822 assert(appendix_box->obj_at(0) == NULL, "");
2823
2824 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2825 JavaCallArguments args;
2826 args.push_oop(Handle(THREAD, caller->java_mirror()));
2827 args.push_oop(bsm);
2828 args.push_oop(method_name);
2829 args.push_oop(method_type);
2830 args.push_oop(info);
2831 args.push_oop(appendix_box);
2832 JavaValue result(T_OBJECT);
2833 JavaCalls::call_static(&result,
2834 SystemDictionary::MethodHandleNatives_klass(),
2835 vmSymbols::linkCallSite_name(),
2836 vmSymbols::linkCallSite_signature(),
2837 &args, CHECK_(empty));
2838 Handle mname(THREAD, (oop) result.get_jobject());
2839 (*method_type_result) = method_type;
2840 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2841 }
2842
2843 // Protection domain cache table handling
2844
2845 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2846 return _pd_cache_table->get(protection_domain);
2847 }
2848
2849 #if INCLUDE_CDS
2850 void SystemDictionary::reorder_dictionary_for_sharing() {
2851 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2852 }
2853 #endif
2854
2855 size_t SystemDictionary::count_bytes_for_buckets() {
2856 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2857 }
2858
2859 size_t SystemDictionary::count_bytes_for_table() {
2860 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2861 }
2862
2863 void SystemDictionary::copy_buckets(char* top, char* end) {
2864 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2865 }
2866
2867 void SystemDictionary::copy_table(char* top, char* end) {
2868 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2869 }
2870
2871 // ----------------------------------------------------------------------------
2872 void SystemDictionary::print_shared(outputStream *st) {
2873 shared_dictionary()->print_on(st);
2874 }
2875
2876 void SystemDictionary::print_on(outputStream *st) {
2877 if (shared_dictionary() != NULL) {
2878 st->print_cr("Shared Dictionary");
2879 shared_dictionary()->print_on(st);
2880 st->cr();
2881 }
2882
2883 GCMutexLocker mu(SystemDictionary_lock);
2884
2885 ClassLoaderDataGraph::print_dictionary(st);
2886
2887 // Placeholders
2888 placeholders()->print_on(st);
2889 st->cr();
2890
2891 // loader constraints - print under SD_lock
2892 constraints()->print_on(st);
2893 st->cr();
2894
2895 _pd_cache_table->print_on(st);
2896 st->cr();
2897 }
2898
2899 void SystemDictionary::verify() {
2900 guarantee(constraints() != NULL,
2901 "Verify of loader constraints failed");
2902 guarantee(placeholders()->number_of_entries() >= 0,
2903 "Verify of placeholders failed");
2904
2905 GCMutexLocker mu(SystemDictionary_lock);
2906
2907 // Verify dictionary
2908 ClassLoaderDataGraph::verify_dictionary();
2909
2910 placeholders()->verify();
2911
2912 // Verify constraint table
2913 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2914 constraints()->verify(placeholders());
2915
2916 _pd_cache_table->verify();
2917 }
2918
2919 void SystemDictionary::dump(outputStream *st, bool verbose) {
2920 assert_locked_or_safepoint(SystemDictionary_lock);
2921 if (verbose) {
2922 print_on(st);
2923 } else {
2924 if (shared_dictionary() != NULL) {
2925 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2926 }
2927 ClassLoaderDataGraph::print_dictionary_statistics(st);
2928 placeholders()->print_table_statistics(st, "Placeholder Table");
2929 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2930 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2931 }
2932 }
2933
2934 // Utility for dumping dictionaries.
2935 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2936 DCmdWithParser(output, heap),
2937 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2938 "BOOLEAN", false, "false") {
2939 _dcmdparser.add_dcmd_option(&_verbose);
2940 }
2941
2942 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2943 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2944 _verbose.value());
2945 VMThread::execute(&dumper);
2946 }
2947
2948 int SystemDictionaryDCmd::num_arguments() {
2949 ResourceMark rm;
2950 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2951 if (dcmd != NULL) {
2952 DCmdMark mark(dcmd);
2953 return dcmd->_dcmdparser.num_arguments();
2954 } else {
2955 return 0;
2956 }
2957 }
2958
2959 class CombineDictionariesClosure : public CLDClosure {
2960 private:
2961 Dictionary* _master_dictionary;
2962 public:
2963 CombineDictionariesClosure(Dictionary* master_dictionary) :
2964 _master_dictionary(master_dictionary) {}
2965 void do_cld(ClassLoaderData* cld) {
2966 ResourceMark rm;
2967 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2968 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
2969 Dictionary* curr_dictionary = cld->dictionary();
2970 DictionaryEntry* p = curr_dictionary->bucket(i);
2971 while (p != NULL) {
2972 Symbol* name = p->instance_klass()->name();
2973 unsigned int d_hash = _master_dictionary->compute_hash(name);
2974 int d_index = _master_dictionary->hash_to_index(d_hash);
2975 DictionaryEntry* next = p->next();
2976 if (p->literal()->class_loader_data() != cld) {
2977 // This is an initiating class loader entry; don't use it
2978 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
2979 curr_dictionary->free_entry(p);
2980 } else {
2981 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
2982 curr_dictionary->unlink_entry(p);
2983 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
2984 _master_dictionary->add_entry(d_index, p);
2985 }
2986 p = next;
2987 }
2988 *curr_dictionary->bucket_addr(i) = NULL;
2989 }
2990 }
2991 }
2992 };
2993
2994 // Combining platform and system loader dictionaries into boot loader dictionaries.
2995 // During run time, we only have one shared dictionary.
2996 void SystemDictionary::combine_shared_dictionaries() {
2997 assert(DumpSharedSpaces, "dump time only");
2998 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
2999 CombineDictionariesClosure cdc(master_dictionary);
3000 ClassLoaderDataGraph::cld_do(&cdc);
3001
3002 // These tables are no longer valid or necessary. Keeping them around will
3003 // cause SystemDictionary::verify() to fail. Let's empty them.
3004 _placeholders = new PlaceholderTable(_placeholder_table_size);
3005 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3006
3007 NOT_PRODUCT(SystemDictionary::verify());
3008 }
3009
3010 // caller needs ResourceMark
3011 const char* SystemDictionary::loader_name(const oop loader) {
3012 return ((loader) == NULL ? "<bootloader>" :
3013 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3014 }
3015
3016 // caller needs ResourceMark
3017 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3018 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3019 SystemDictionary::loader_name(loader_data->class_loader()));
3020 }