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 "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/protectionDomainCache.hpp"
39 #include "classfile/resolutionErrors.hpp"
40 #include "classfile/stringTable.hpp"
41 #include "classfile/systemDictionary.hpp"
42 #include "classfile/vmSymbols.hpp"
43 #include "code/codeCache.hpp"
44 #include "compiler/compileBroker.hpp"
45 #include "gc/shared/gcLocker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "interpreter/bytecodeStream.hpp"
48 #include "interpreter/interpreter.hpp"
49 #include "logging/log.hpp"
50 #include "logging/logStream.hpp"
51 #include "memory/filemap.hpp"
52 #include "memory/metaspaceClosure.hpp"
53 #include "memory/oopFactory.hpp"
54 #include "memory/resourceArea.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/instanceRefKlass.hpp"
57 #include "oops/klass.inline.hpp"
58 #include "oops/methodData.hpp"
59 #include "oops/objArrayKlass.hpp"
60 #include "oops/objArrayOop.inline.hpp"
61 #include "oops/oop.inline.hpp"
62 #include "oops/symbol.hpp"
63 #include "oops/typeArrayKlass.hpp"
64 #include "prims/jvm.h"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/biasedLocking.hpp"
70 #include "runtime/fieldType.hpp"
71 #include "runtime/handles.inline.hpp"
72 #include "runtime/java.hpp"
73 #include "runtime/javaCalls.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.inline.hpp"
76 #include "runtime/signature.hpp"
77 #include "services/classLoadingService.hpp"
78 #include "services/diagnosticCommand.hpp"
79 #include "services/threadService.hpp"
80 #include "trace/traceMacros.hpp"
81 #include "utilities/macros.hpp"
82 #include "utilities/ticks.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 #if INCLUDE_TRACE
91 #include "trace/tracing.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 Dictionary* SystemDictionary::_shared_dictionary = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 int SystemDictionary::_number_of_modifications = 0;
102 oop SystemDictionary::_system_loader_lock_obj = NULL;
103
104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
105 = { NULL /*, NULL...*/ };
106
107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
108
109 oop SystemDictionary::_java_system_loader = NULL;
110
111 bool SystemDictionary::_has_loadClassInternal = false;
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // lazily initialized klass variables
115 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
116
117 // Default ProtectionDomainCacheSize value
118
119 const int defaultProtectionDomainCacheSize = 1009;
120
121
122 // ----------------------------------------------------------------------------
123 // Java-level SystemLoader
124
125 oop SystemDictionary::java_system_loader() {
126 return _java_system_loader;
127 }
128
129 void SystemDictionary::compute_java_system_loader(TRAPS) {
130 Klass* system_klass = WK_KLASS(ClassLoader_klass);
131 JavaValue result(T_OBJECT);
132 JavaCalls::call_static(&result,
133 WK_KLASS(ClassLoader_klass),
134 vmSymbols::getSystemClassLoader_name(),
135 vmSymbols::void_classloader_signature(),
136 CHECK);
137
138 _java_system_loader = (oop)result.get_jobject();
139
140 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
141 }
142
143
144 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
145 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
146 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
147 }
148
149 // ----------------------------------------------------------------------------
150 // Parallel class loading check
151
152 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
153 if (UnsyncloadClass || class_loader.is_null()) return true;
154 if (AlwaysLockClassLoader) return false;
155 return java_lang_ClassLoader::parallelCapable(class_loader());
156 }
157 // ----------------------------------------------------------------------------
158 // ParallelDefineClass flag does not apply to bootclass loader
159 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
160 if (class_loader.is_null()) return false;
161 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
162 return true;
163 }
164 return false;
165 }
166
167 // Returns true if the passed class loader is the builtin application class loader
168 // or a custom system class loader. A customer system class loader can be
169 // specified via -Djava.system.class.loader.
170 bool SystemDictionary::is_system_class_loader(oop class_loader) {
171 if (class_loader == NULL) {
172 return false;
173 }
174 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
175 class_loader == _java_system_loader);
176 }
177
178 // Returns true if the passed class loader is the platform class loader.
179 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
184 }
185
186 // ----------------------------------------------------------------------------
187 // Resolving of classes
188
189 // Forwards to resolve_or_null
190
191 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
192 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
193 if (HAS_PENDING_EXCEPTION || klass == NULL) {
194 // can return a null klass
195 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
196 }
197 return klass;
198 }
199
200 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
201 bool throw_error,
202 Klass* klass, TRAPS) {
203 if (HAS_PENDING_EXCEPTION) {
204 // If we have a pending exception we forward it to the caller, unless throw_error is true,
205 // in which case we have to check whether the pending exception is a ClassNotFoundException,
206 // and if so convert it to a NoClassDefFoundError
207 // And chain the original ClassNotFoundException
208 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
209 ResourceMark rm(THREAD);
210 assert(klass == NULL, "Should not have result with exception pending");
211 Handle e(THREAD, PENDING_EXCEPTION);
212 CLEAR_PENDING_EXCEPTION;
213 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
214 } else {
215 return NULL;
216 }
217 }
218 // Class not found, throw appropriate error or exception depending on value of throw_error
219 if (klass == NULL) {
220 ResourceMark rm(THREAD);
221 if (throw_error) {
222 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
223 } else {
224 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
225 }
226 }
227 return klass;
228 }
229
230
231 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
232 bool throw_error, TRAPS)
233 {
234 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
235 }
236
237
238 // Forwards to resolve_instance_class_or_null
239
240 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
241 assert(THREAD->can_call_java(),
242 "can not load classes with compiler thread: class=%s, classloader=%s",
243 class_name->as_C_string(),
244 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
245 if (FieldType::is_array(class_name)) {
246 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
247 } else if (FieldType::is_obj(class_name)) {
248 ResourceMark rm(THREAD);
249 // Ignore wrapping L and ;.
250 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
251 class_name->utf8_length() - 2, CHECK_NULL);
252 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
253 } else {
254 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
255 }
256 }
257
258 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
259 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
260 }
261
262 // Forwards to resolve_instance_class_or_null
263
264 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
265 Handle class_loader,
266 Handle protection_domain,
267 TRAPS) {
268 assert(FieldType::is_array(class_name), "must be array");
269 Klass* k = NULL;
270 FieldArrayInfo fd;
271 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
272 // of this call
273 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
274 if (t == T_OBJECT) {
275 // naked oop "k" is OK here -- we assign back into it
276 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
277 class_loader,
278 protection_domain,
279 CHECK_NULL);
280 if (k != NULL) {
281 k = k->array_klass(fd.dimension(), CHECK_NULL);
282 }
283 } else {
284 k = Universe::typeArrayKlassObj(t);
285 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
286 }
287 return k;
288 }
289
290
291 // Must be called for any super-class or super-interface resolution
292 // during class definition to allow class circularity checking
293 // super-interface callers:
294 // parse_interfaces - for defineClass & jvmtiRedefineClasses
295 // super-class callers:
296 // ClassFileParser - for defineClass & jvmtiRedefineClasses
297 // load_shared_class - while loading a class from shared archive
298 // resolve_instance_class_or_null:
299 // via: handle_parallel_super_load
300 // when resolving a class that has an existing placeholder with
301 // a saved superclass [i.e. a defineClass is currently in progress]
302 // if another thread is trying to resolve the class, it must do
303 // super-class checks on its own thread to catch class circularity
304 // This last call is critical in class circularity checking for cases
305 // where classloading is delegated to different threads and the
306 // classloader lock is released.
307 // Take the case: Base->Super->Base
308 // 1. If thread T1 tries to do a defineClass of class Base
309 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
310 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
311 // so it tries to load Super
312 // 3. If we load the class internally, or user classloader uses same thread
313 // loadClassFromxxx or defineClass via parseClassFile Super ...
314 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
315 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
316 // 3.4 calls resolve_super_or_fail Base
317 // 3.5 finds T1,Base -> throws class circularity
318 //OR 4. If T2 tries to resolve Super via defineClass Super ...
319 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
320 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
321 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
322 // 4.4 finds T2, Super -> throws class circularity
323 // Must be called, even if superclass is null, since this is
324 // where the placeholder entry is created which claims this
325 // thread is loading this class/classloader.
326 // Be careful when modifying this code: once you have run
327 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
328 // you need to find_and_remove it before returning.
329 // So be careful to not exit with a CHECK_ macro betweeen these calls.
330 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
331 Symbol* class_name,
332 Handle class_loader,
333 Handle protection_domain,
334 bool is_superclass,
335 TRAPS) {
336 #if INCLUDE_CDS
337 if (DumpSharedSpaces) {
338 // Special processing for CDS dump time.
339 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
340 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
341 if (k) {
342 return k;
343 }
344 }
345 #endif // INCLUDE_CDS
346
347 // Double-check, if child class is already loaded, just return super-class,interface
348 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
349 // dictionary.
350 // Make sure there's a placeholder for the *child* before resolving.
351 // Used as a claim that this thread is currently loading superclass/classloader
352 // Used here for ClassCircularity checks and also for heap verification
353 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
354 // Must check ClassCircularity before checking if super class is already loaded.
355 //
356 // We might not already have a placeholder if this child_name was
357 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
358 // the name of the class might not be known until the stream is actually
359 // parsed.
360 // Bugs 4643874, 4715493
361
362 ClassLoaderData* loader_data = class_loader_data(class_loader);
363 Dictionary* dictionary = loader_data->dictionary();
364 unsigned int d_hash = dictionary->compute_hash(child_name);
365 int d_index = dictionary->hash_to_index(d_hash);
366 unsigned int p_hash = placeholders()->compute_hash(child_name);
367 int p_index = placeholders()->hash_to_index(p_hash);
368 // can't throw error holding a lock
369 bool child_already_loaded = false;
370 bool throw_circularity_error = false;
371 {
372 MutexLocker mu(SystemDictionary_lock, THREAD);
373 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
374 Klass* quicksuperk;
375 // to support // loading: if child done loading, just return superclass
376 // if class_name, & class_loader don't match:
377 // if initial define, SD update will give LinkageError
378 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
379 // so we don't throw an exception here.
380 // see: nsk redefclass014 & java.lang.instrument Instrument032
381 if ((childk != NULL ) && (is_superclass) &&
382 ((quicksuperk = childk->super()) != NULL) &&
383
384 ((quicksuperk->name() == class_name) &&
385 (quicksuperk->class_loader() == class_loader()))) {
386 return quicksuperk;
387 } else {
388 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
389 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
390 throw_circularity_error = true;
391 }
392 }
393 if (!throw_circularity_error) {
394 // Be careful not to exit resolve_super
395 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
396 }
397 }
398 if (throw_circularity_error) {
399 ResourceMark rm(THREAD);
400 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
401 }
402
403 // java.lang.Object should have been found above
404 assert(class_name != NULL, "null super class for resolving");
405 // Resolve the super class or interface, check results on return
406 Klass* superk = SystemDictionary::resolve_or_null(class_name,
407 class_loader,
408 protection_domain,
409 THREAD);
410
411 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
412 // It is no longer necessary to keep the placeholder table alive until update_dictionary
413 // or error. GC used to walk the placeholder table as strong roots.
414 // The instanceKlass is kept alive because the class loader is on the stack,
415 // which keeps the loader_data alive, as well as all instanceKlasses in
416 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
417 {
418 MutexLocker mu(SystemDictionary_lock, THREAD);
419 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
420 SystemDictionary_lock->notify_all();
421 }
422 if (HAS_PENDING_EXCEPTION || superk == NULL) {
423 // can null superk
424 superk = handle_resolution_exception(class_name, true, superk, THREAD);
425 }
426
427 return superk;
428 }
429
430 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
431 Handle class_loader,
432 Handle protection_domain,
433 TRAPS) {
434 if(!has_checkPackageAccess()) return;
435
436 // Now we have to call back to java to check if the initating class has access
437 JavaValue result(T_VOID);
438 LogTarget(Debug, protectiondomain) lt;
439 if (lt.is_enabled()) {
440 ResourceMark rm;
441 // Print out trace information
442 LogStream ls(lt);
443 ls.print_cr("Checking package access");
444 ls.print("class loader: "); class_loader()->print_value_on(&ls);
445 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
446 ls.print(" loading: "); klass->print_value_on(&ls);
447 ls.cr();
448 }
449
450 // This handle and the class_loader handle passed in keeps this class from
451 // being unloaded through several GC points.
452 // The class_loader handle passed in is the initiating loader.
453 Handle mirror(THREAD, klass->java_mirror());
454
455 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
456 JavaCalls::call_special(&result,
457 class_loader,
458 system_loader,
459 vmSymbols::checkPackageAccess_name(),
460 vmSymbols::class_protectiondomain_signature(),
461 mirror,
462 protection_domain,
463 THREAD);
464
465 if (HAS_PENDING_EXCEPTION) {
466 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
467 } else {
468 log_debug(protectiondomain)("granted");
469 }
470
471 if (HAS_PENDING_EXCEPTION) return;
472
473 // If no exception has been thrown, we have validated the protection domain
474 // Insert the protection domain of the initiating class into the set.
475 {
476 ClassLoaderData* loader_data = class_loader_data(class_loader);
477 Dictionary* dictionary = loader_data->dictionary();
478
479 Symbol* kn = klass->name();
480 unsigned int d_hash = dictionary->compute_hash(kn);
481 int d_index = dictionary->hash_to_index(d_hash);
482
483 MutexLocker mu(SystemDictionary_lock, THREAD);
484 dictionary->add_protection_domain(d_index, d_hash, klass,
485 protection_domain, THREAD);
486 }
487 }
488
489 // We only get here if this thread finds that another thread
490 // has already claimed the placeholder token for the current operation,
491 // but that other thread either never owned or gave up the
492 // object lock
493 // Waits on SystemDictionary_lock to indicate placeholder table updated
494 // On return, caller must recheck placeholder table state
495 //
496 // We only get here if
497 // 1) custom classLoader, i.e. not bootstrap classloader
498 // 2) UnsyncloadClass not set
499 // 3) custom classLoader has broken the class loader objectLock
500 // so another thread got here in parallel
501 //
502 // lockObject must be held.
503 // Complicated dance due to lock ordering:
504 // Must first release the classloader object lock to
505 // allow initial definer to complete the class definition
506 // and to avoid deadlock
507 // Reclaim classloader lock object with same original recursion count
508 // Must release SystemDictionary_lock after notify, since
509 // class loader lock must be claimed before SystemDictionary_lock
510 // to prevent deadlocks
511 //
512 // The notify allows applications that did an untimed wait() on
513 // the classloader object lock to not hang.
514 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
515 assert_lock_strong(SystemDictionary_lock);
516
517 bool calledholdinglock
518 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
519 assert(calledholdinglock,"must hold lock for notify");
520 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
521 ObjectSynchronizer::notifyall(lockObject, THREAD);
522 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
523 SystemDictionary_lock->wait();
524 SystemDictionary_lock->unlock();
525 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
526 SystemDictionary_lock->lock();
527 }
528
529 // If the class in is in the placeholder table, class loading is in progress
530 // For cases where the application changes threads to load classes, it
531 // is critical to ClassCircularity detection that we try loading
532 // the superclass on the same thread internally, so we do parallel
533 // super class loading here.
534 // This also is critical in cases where the original thread gets stalled
535 // even in non-circularity situations.
536 // Note: must call resolve_super_or_fail even if null super -
537 // to force placeholder entry creation for this class for circularity detection
538 // Caller must check for pending exception
539 // Returns non-null Klass* if other thread has completed load
540 // and we are done,
541 // If return null Klass* and no pending exception, the caller must load the class
542 InstanceKlass* SystemDictionary::handle_parallel_super_load(
543 Symbol* name, Symbol* superclassname, Handle class_loader,
544 Handle protection_domain, Handle lockObject, TRAPS) {
545
546 ClassLoaderData* loader_data = class_loader_data(class_loader);
547 Dictionary* dictionary = loader_data->dictionary();
548 unsigned int d_hash = dictionary->compute_hash(name);
549 int d_index = dictionary->hash_to_index(d_hash);
550 unsigned int p_hash = placeholders()->compute_hash(name);
551 int p_index = placeholders()->hash_to_index(p_hash);
552
553 // superk is not used, resolve_super called for circularity check only
554 // This code is reached in two situations. One if this thread
555 // is loading the same class twice (e.g. ClassCircularity, or
556 // java.lang.instrument).
557 // The second is if another thread started the resolve_super first
558 // and has not yet finished.
559 // In both cases the original caller will clean up the placeholder
560 // entry on error.
561 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
562 superclassname,
563 class_loader,
564 protection_domain,
565 true,
566 CHECK_NULL);
567
568 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
569 // Serial class loaders and bootstrap classloader do wait for superclass loads
570 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
571 MutexLocker mu(SystemDictionary_lock, THREAD);
572 // Check if classloading completed while we were loading superclass or waiting
573 return find_class(d_index, d_hash, name, dictionary);
574 }
575
576 // must loop to both handle other placeholder updates
577 // and spurious notifications
578 bool super_load_in_progress = true;
579 PlaceholderEntry* placeholder;
580 while (super_load_in_progress) {
581 MutexLocker mu(SystemDictionary_lock, THREAD);
582 // Check if classloading completed while we were loading superclass or waiting
583 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
584 if (check != NULL) {
585 // Klass is already loaded, so just return it
586 return check;
587 } else {
588 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
589 if (placeholder && placeholder->super_load_in_progress() ){
590 // Before UnsyncloadClass:
591 // We only get here if the application has released the
592 // classloader lock when another thread was in the middle of loading a
593 // superclass/superinterface for this class, and now
594 // this thread is also trying to load this class.
595 // To minimize surprises, the first thread that started to
596 // load a class should be the one to complete the loading
597 // with the classfile it initially expected.
598 // This logic has the current thread wait once it has done
599 // all the superclass/superinterface loading it can, until
600 // the original thread completes the class loading or fails
601 // If it completes we will use the resulting InstanceKlass
602 // which we will find below in the systemDictionary.
603 // We also get here for parallel bootstrap classloader
604 if (class_loader.is_null()) {
605 SystemDictionary_lock->wait();
606 } else {
607 double_lock_wait(lockObject, THREAD);
608 }
609 } else {
610 // If not in SD and not in PH, other thread's load must have failed
611 super_load_in_progress = false;
612 }
613 }
614 }
615 return NULL;
616 }
617
618 static void post_class_load_event(const Ticks& start_time,
619 InstanceKlass* k,
620 const ClassLoaderData* init_cld) {
621 #if INCLUDE_TRACE
622 EventClassLoad event(UNTIMED);
623 if (event.should_commit()) {
624 event.set_starttime(start_time);
625 event.set_loadedClass(k);
626 event.set_definingClassLoader(k->class_loader_data());
627 event.set_initiatingClassLoader(init_cld);
628 event.commit();
629 }
630 #endif // INCLUDE_TRACE
631 }
632
633 static void class_define_event(InstanceKlass* k,
634 const ClassLoaderData* def_cld) {
635 #if INCLUDE_TRACE
636 EventClassDefine event;
637 if (event.should_commit()) {
638 event.set_definedClass(k);
639 event.set_definingClassLoader(def_cld);
640 event.commit();
641 }
642 #endif // INCLUDE_TRACE
643 }
644
645 // Be careful when modifying this code: once you have run
646 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
647 // you need to find_and_remove it before returning.
648 // So be careful to not exit with a CHECK_ macro betweeen these calls.
649 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
650 Handle class_loader,
651 Handle protection_domain,
652 TRAPS) {
653 assert(name != NULL && !FieldType::is_array(name) &&
654 !FieldType::is_obj(name), "invalid class name");
655
656 Ticks class_load_start_time = Ticks::now();
657
658 HandleMark hm(THREAD);
659
660 // Fix for 4474172; see evaluation for more details
661 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
662 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
663 Dictionary* dictionary = loader_data->dictionary();
664
665 // Do lookup to see if class already exist and the protection domain
666 // has the right access
667 // This call uses find which checks protection domain already matches
668 // All subsequent calls use find_class, and set has_loaded_class so that
669 // before we return a result we call out to java to check for valid protection domain
670 // to allow returning the Klass* and add it to the pd_set if it is valid
671 unsigned int d_hash = dictionary->compute_hash(name);
672 int d_index = dictionary->hash_to_index(d_hash);
673 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
674 if (probe != NULL) return probe;
675
676
677 // Non-bootstrap class loaders will call out to class loader and
678 // define via jvm/jni_DefineClass which will acquire the
679 // class loader object lock to protect against multiple threads
680 // defining the class in parallel by accident.
681 // This lock must be acquired here so the waiter will find
682 // any successful result in the SystemDictionary and not attempt
683 // the define
684 // ParallelCapable Classloaders and the bootstrap classloader,
685 // or all classloaders with UnsyncloadClass do not acquire lock here
686 bool DoObjectLock = true;
687 if (is_parallelCapable(class_loader)) {
688 DoObjectLock = false;
689 }
690
691 unsigned int p_hash = placeholders()->compute_hash(name);
692 int p_index = placeholders()->hash_to_index(p_hash);
693
694 // Class is not in SystemDictionary so we have to do loading.
695 // Make sure we are synchronized on the class loader before we proceed
696 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
697 check_loader_lock_contention(lockObject, THREAD);
698 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
699
700 // Check again (after locking) if class already exist in SystemDictionary
701 bool class_has_been_loaded = false;
702 bool super_load_in_progress = false;
703 bool havesupername = false;
704 InstanceKlass* k = NULL;
705 PlaceholderEntry* placeholder;
706 Symbol* superclassname = NULL;
707
708 {
709 MutexLocker mu(SystemDictionary_lock, THREAD);
710 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
711 if (check != NULL) {
712 // Klass is already loaded, so just return it
713 class_has_been_loaded = true;
714 k = check;
715 } else {
716 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
717 if (placeholder && placeholder->super_load_in_progress()) {
718 super_load_in_progress = true;
719 if (placeholder->havesupername() == true) {
720 superclassname = placeholder->supername();
721 havesupername = true;
722 }
723 }
724 }
725 }
726
727 // If the class is in the placeholder table, class loading is in progress
728 if (super_load_in_progress && havesupername==true) {
729 k = handle_parallel_super_load(name,
730 superclassname,
731 class_loader,
732 protection_domain,
733 lockObject, THREAD);
734 if (HAS_PENDING_EXCEPTION) {
735 return NULL;
736 }
737 if (k != NULL) {
738 class_has_been_loaded = true;
739 }
740 }
741
742 bool throw_circularity_error = false;
743 if (!class_has_been_loaded) {
744 bool load_instance_added = false;
745
746 // add placeholder entry to record loading instance class
747 // Five cases:
748 // All cases need to prevent modifying bootclasssearchpath
749 // in parallel with a classload of same classname
750 // Redefineclasses uses existence of the placeholder for the duration
751 // of the class load to prevent concurrent redefinition of not completely
752 // defined classes.
753 // case 1. traditional classloaders that rely on the classloader object lock
754 // - no other need for LOAD_INSTANCE
755 // case 2. traditional classloaders that break the classloader object lock
756 // as a deadlock workaround. Detection of this case requires that
757 // this check is done while holding the classloader object lock,
758 // and that lock is still held when calling classloader's loadClass.
759 // For these classloaders, we ensure that the first requestor
760 // completes the load and other requestors wait for completion.
761 // case 3. UnsyncloadClass - don't use objectLocker
762 // With this flag, we allow parallel classloading of a
763 // class/classloader pair
764 // case4. Bootstrap classloader - don't own objectLocker
765 // This classloader supports parallelism at the classloader level,
766 // but only allows a single load of a class/classloader pair.
767 // No performance benefit and no deadlock issues.
768 // case 5. parallelCapable user level classloaders - without objectLocker
769 // Allow parallel classloading of a class/classloader pair
770
771 {
772 MutexLocker mu(SystemDictionary_lock, THREAD);
773 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
774 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
775 if (oldprobe) {
776 // only need check_seen_thread once, not on each loop
777 // 6341374 java/lang/Instrument with -Xcomp
778 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
779 throw_circularity_error = true;
780 } else {
781 // case 1: traditional: should never see load_in_progress.
782 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
783
784 // case 4: bootstrap classloader: prevent futile classloading,
785 // wait on first requestor
786 if (class_loader.is_null()) {
787 SystemDictionary_lock->wait();
788 } else {
789 // case 2: traditional with broken classloader lock. wait on first
790 // requestor.
791 double_lock_wait(lockObject, THREAD);
792 }
793 // Check if classloading completed while we were waiting
794 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
795 if (check != NULL) {
796 // Klass is already loaded, so just return it
797 k = check;
798 class_has_been_loaded = true;
799 }
800 // check if other thread failed to load and cleaned up
801 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
802 }
803 }
804 }
805 }
806 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
807 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
808 // LOAD_INSTANCE in parallel
809
810 if (!throw_circularity_error && !class_has_been_loaded) {
811 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
812 load_instance_added = true;
813 // For class loaders that do not acquire the classloader object lock,
814 // if they did not catch another thread holding LOAD_INSTANCE,
815 // need a check analogous to the acquire ObjectLocker/find_class
816 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
817 // one final check if the load has already completed
818 // class loaders holding the ObjectLock shouldn't find the class here
819 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
820 if (check != NULL) {
821 // Klass is already loaded, so return it after checking/adding protection domain
822 k = check;
823 class_has_been_loaded = true;
824 }
825 }
826 }
827
828 // must throw error outside of owning lock
829 if (throw_circularity_error) {
830 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
831 ResourceMark rm(THREAD);
832 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
833 }
834
835 if (!class_has_been_loaded) {
836
837 // Do actual loading
838 k = load_instance_class(name, class_loader, THREAD);
839
840 // For UnsyncloadClass only
841 // If they got a linkageError, check if a parallel class load succeeded.
842 // If it did, then for bytecode resolution the specification requires
843 // that we return the same result we did for the other thread, i.e. the
844 // successfully loaded InstanceKlass
845 // Should not get here for classloaders that support parallelism
846 // with the new cleaner mechanism, even with AllowParallelDefineClass
847 // Bootstrap goes through here to allow for an extra guarantee check
848 if (UnsyncloadClass || (class_loader.is_null())) {
849 if (k == NULL && HAS_PENDING_EXCEPTION
850 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
851 MutexLocker mu(SystemDictionary_lock, THREAD);
852 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
853 if (check != NULL) {
854 // Klass is already loaded, so just use it
855 k = check;
856 CLEAR_PENDING_EXCEPTION;
857 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
858 }
859 }
860 }
861
862 // If everything was OK (no exceptions, no null return value), and
863 // class_loader is NOT the defining loader, do a little more bookkeeping.
864 if (!HAS_PENDING_EXCEPTION && k != NULL &&
865 k->class_loader() != class_loader()) {
866
867 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
868
869 // Need to check for a PENDING_EXCEPTION again; check_constraints
870 // can throw and doesn't use the CHECK macro.
871 if (!HAS_PENDING_EXCEPTION) {
872 { // Grabbing the Compile_lock prevents systemDictionary updates
873 // during compilations.
874 MutexLocker mu(Compile_lock, THREAD);
875 update_dictionary(d_index, d_hash, p_index, p_hash,
876 k, class_loader, THREAD);
877 }
878
879 if (JvmtiExport::should_post_class_load()) {
880 Thread *thread = THREAD;
881 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
882 JvmtiExport::post_class_load((JavaThread *) thread, k);
883 }
884 }
885 }
886 } // load_instance_class
887
888 if (load_instance_added == true) {
889 // clean up placeholder entries for LOAD_INSTANCE success or error
890 // This brackets the SystemDictionary updates for both defining
891 // and initiating loaders
892 MutexLocker mu(SystemDictionary_lock, THREAD);
893 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
894 SystemDictionary_lock->notify_all();
895 }
896 }
897
898 if (HAS_PENDING_EXCEPTION || k == NULL) {
899 return NULL;
900 }
901
902 post_class_load_event(class_load_start_time, k, loader_data);
903
904 #ifdef ASSERT
905 {
906 ClassLoaderData* loader_data = k->class_loader_data();
907 MutexLocker mu(SystemDictionary_lock, THREAD);
908 Klass* kk = find_class(name, loader_data);
909 assert(kk == k, "should be present in dictionary");
910 }
911 #endif
912
913 // return if the protection domain in NULL
914 if (protection_domain() == NULL) return k;
915
916 // Check the protection domain has the right access
917 {
918 MutexLocker mu(SystemDictionary_lock, THREAD);
919 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
920 protection_domain)) {
921 return k;
922 }
923 }
924
925 // Verify protection domain. If it fails an exception is thrown
926 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
927
928 return k;
929 }
930
931
932 // This routine does not lock the system dictionary.
933 //
934 // Since readers don't hold a lock, we must make sure that system
935 // dictionary entries are only removed at a safepoint (when only one
936 // thread is running), and are added to in a safe way (all links must
937 // be updated in an MT-safe manner).
938 //
939 // Callers should be aware that an entry could be added just after
940 // _dictionary->bucket(index) is read here, so the caller will not see
941 // the new entry.
942
943 Klass* SystemDictionary::find(Symbol* class_name,
944 Handle class_loader,
945 Handle protection_domain,
946 TRAPS) {
947
948 // The result of this call should be consistent with the result
949 // of the call to resolve_instance_class_or_null().
950 // See evaluation 6790209 and 4474172 for more details.
951 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
952 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
953
954 if (loader_data == NULL) {
955 // If the ClassLoaderData has not been setup,
956 // then the class loader has no entries in the dictionary.
957 return NULL;
958 }
959
960 Dictionary* dictionary = loader_data->dictionary();
961 unsigned int d_hash = dictionary->compute_hash(class_name);
962 int d_index = dictionary->hash_to_index(d_hash);
963 return dictionary->find(d_index, d_hash, class_name,
964 protection_domain);
965 }
966
967
968 // Look for a loaded instance or array klass by name. Do not do any loading.
969 // return NULL in case of error.
970 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
971 Handle class_loader,
972 Handle protection_domain,
973 TRAPS) {
974 Klass* k = NULL;
975 assert(class_name != NULL, "class name must be non NULL");
976
977 if (FieldType::is_array(class_name)) {
978 // The name refers to an array. Parse the name.
979 // dimension and object_key in FieldArrayInfo are assigned as a
980 // side-effect of this call
981 FieldArrayInfo fd;
982 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
983 if (t != T_OBJECT) {
984 k = Universe::typeArrayKlassObj(t);
985 } else {
986 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
987 }
988 if (k != NULL) {
989 k = k->array_klass_or_null(fd.dimension());
990 }
991 } else {
992 k = find(class_name, class_loader, protection_domain, THREAD);
993 }
994 return k;
995 }
996
997 // Note: this method is much like resolve_from_stream, but
998 // does not publish the classes via the SystemDictionary.
999 // Handles unsafe_DefineAnonymousClass and redefineclasses
1000 // RedefinedClasses do not add to the class hierarchy
1001 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1002 Handle class_loader,
1003 Handle protection_domain,
1004 ClassFileStream* st,
1005 const InstanceKlass* host_klass,
1006 GrowableArray<Handle>* cp_patches,
1007 TRAPS) {
1008
1009 Ticks class_load_start_time = Ticks::now();
1010
1011 ClassLoaderData* loader_data;
1012 if (host_klass != NULL) {
1013 // Create a new CLD for anonymous class, that uses the same class loader
1014 // as the host_klass
1015 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1016 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1017 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1018 } else {
1019 loader_data = ClassLoaderData::class_loader_data(class_loader());
1020 }
1021
1022 assert(st != NULL, "invariant");
1023 assert(st->need_verify(), "invariant");
1024
1025 // Parse stream and create a klass.
1026 // Note that we do this even though this klass might
1027 // already be present in the SystemDictionary, otherwise we would not
1028 // throw potential ClassFormatErrors.
1029
1030 InstanceKlass* k = KlassFactory::create_from_stream(st,
1031 class_name,
1032 loader_data,
1033 protection_domain,
1034 host_klass,
1035 cp_patches,
1036 CHECK_NULL);
1037
1038 if (host_klass != NULL && k != NULL) {
1039 // If it's anonymous, initialize it now, since nobody else will.
1040
1041 {
1042 MutexLocker mu_r(Compile_lock, THREAD);
1043
1044 // Add to class hierarchy, initialize vtables, and do possible
1045 // deoptimizations.
1046 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1047
1048 // But, do not add to dictionary.
1049
1050 // compiled code dependencies need to be validated anyway
1051 notice_modification();
1052 }
1053
1054 // Rewrite and patch constant pool here.
1055 k->link_class(CHECK_NULL);
1056 if (cp_patches != NULL) {
1057 k->constants()->patch_resolved_references(cp_patches);
1058 }
1059 k->eager_initialize(CHECK_NULL);
1060
1061 // notify jvmti
1062 if (JvmtiExport::should_post_class_load()) {
1063 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1064 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1065 }
1066
1067 post_class_load_event(class_load_start_time, k, loader_data);
1068 }
1069 assert(host_klass != NULL || NULL == cp_patches,
1070 "cp_patches only found with host_klass");
1071
1072 return k;
1073 }
1074
1075 // Add a klass to the system from a stream (called by jni_DefineClass and
1076 // JVM_DefineClass).
1077 // Note: class_name can be NULL. In that case we do not know the name of
1078 // the class until we have parsed the stream.
1079
1080 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1081 Handle class_loader,
1082 Handle protection_domain,
1083 ClassFileStream* st,
1084 TRAPS) {
1085
1086 HandleMark hm(THREAD);
1087
1088 // Classloaders that support parallelism, e.g. bootstrap classloader,
1089 // or all classloaders with UnsyncloadClass do not acquire lock here
1090 bool DoObjectLock = true;
1091 if (is_parallelCapable(class_loader)) {
1092 DoObjectLock = false;
1093 }
1094
1095 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1096
1097 // Make sure we are synchronized on the class loader before we proceed
1098 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1099 check_loader_lock_contention(lockObject, THREAD);
1100 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1101
1102 assert(st != NULL, "invariant");
1103
1104 // Parse the stream and create a klass.
1105 // Note that we do this even though this klass might
1106 // already be present in the SystemDictionary, otherwise we would not
1107 // throw potential ClassFormatErrors.
1108 InstanceKlass* k = NULL;
1109
1110 #if INCLUDE_CDS
1111 k = SystemDictionaryShared::lookup_from_stream(class_name,
1112 class_loader,
1113 protection_domain,
1114 st,
1115 CHECK_NULL);
1116 #endif
1117
1118 if (k == NULL) {
1119 if (st->buffer() == NULL) {
1120 return NULL;
1121 }
1122 k = KlassFactory::create_from_stream(st,
1123 class_name,
1124 loader_data,
1125 protection_domain,
1126 NULL, // host_klass
1127 NULL, // cp_patches
1128 CHECK_NULL);
1129 }
1130
1131 assert(k != NULL, "no klass created");
1132 Symbol* h_name = k->name();
1133 assert(class_name == NULL || class_name == h_name, "name mismatch");
1134
1135 // Add class just loaded
1136 // If a class loader supports parallel classloading handle parallel define requests
1137 // find_or_define_instance_class may return a different InstanceKlass
1138 if (is_parallelCapable(class_loader)) {
1139 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1140 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1141 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1142 assert(defined_k != NULL, "Should have a klass if there's no exception");
1143 loader_data->add_to_deallocate_list(k);
1144 k = defined_k;
1145 }
1146 } else {
1147 define_instance_class(k, THREAD);
1148 }
1149
1150 // If defining the class throws an exception register 'k' for cleanup.
1151 if (HAS_PENDING_EXCEPTION) {
1152 assert(k != NULL, "Must have an instance klass here!");
1153 loader_data->add_to_deallocate_list(k);
1154 return NULL;
1155 }
1156
1157 // Make sure we have an entry in the SystemDictionary on success
1158 debug_only( {
1159 MutexLocker mu(SystemDictionary_lock, THREAD);
1160
1161 Klass* check = find_class(h_name, k->class_loader_data());
1162 assert(check == k, "should be present in the dictionary");
1163 } );
1164
1165 return k;
1166 }
1167
1168 #if INCLUDE_CDS
1169 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1170 int number_of_entries) {
1171 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1172 "bad shared dictionary size.");
1173 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1174 _shared_dictionary_size, t, number_of_entries);
1175 }
1176
1177
1178 // If there is a shared dictionary, then find the entry for the
1179 // given shared system class, if any.
1180
1181 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1182 if (shared_dictionary() != NULL) {
1183 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1184 int d_index = shared_dictionary()->hash_to_index(d_hash);
1185
1186 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1187 } else {
1188 return NULL;
1189 }
1190 }
1191
1192
1193 // Load a class from the shared spaces (found through the shared system
1194 // dictionary). Force the superclass and all interfaces to be loaded.
1195 // Update the class definition to include sibling classes and no
1196 // subclasses (yet). [Classes in the shared space are not part of the
1197 // object hierarchy until loaded.]
1198
1199 InstanceKlass* SystemDictionary::load_shared_class(
1200 Symbol* class_name, Handle class_loader, TRAPS) {
1201 InstanceKlass* ik = find_shared_class(class_name);
1202 // Make sure we only return the boot class for the NULL classloader.
1203 if (ik != NULL &&
1204 ik->is_shared_boot_class() && class_loader.is_null()) {
1205 Handle protection_domain;
1206 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1207 }
1208 return NULL;
1209 }
1210
1211 // Check if a shared class can be loaded by the specific classloader:
1212 //
1213 // NULL classloader:
1214 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1215 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1216 // be defined in an unnamed module.
1217 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1218 InstanceKlass* ik,
1219 Handle class_loader, TRAPS) {
1220 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1221 "Cannot use sharing if java.base is patched");
1222 ResourceMark rm;
1223 int path_index = ik->shared_classpath_index();
1224 SharedClassPathEntry* ent =
1225 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1226 if (!Universe::is_module_initialized()) {
1227 assert(ent != NULL && ent->is_jrt(),
1228 "Loading non-bootstrap classes before the module system is initialized");
1229 assert(class_loader.is_null(), "sanity");
1230 return true;
1231 }
1232 // Get the pkg_entry from the classloader
1233 TempNewSymbol pkg_name = NULL;
1234 PackageEntry* pkg_entry = NULL;
1235 ModuleEntry* mod_entry = NULL;
1236 const char* pkg_string = NULL;
1237 ClassLoaderData* loader_data = class_loader_data(class_loader);
1238 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1239 if (pkg_name != NULL) {
1240 pkg_string = pkg_name->as_C_string();
1241 if (loader_data != NULL) {
1242 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1243 }
1244 if (pkg_entry != NULL) {
1245 mod_entry = pkg_entry->module();
1246 }
1247 }
1248
1249 // If the archived class is from a module that has been patched at runtime,
1250 // the class cannot be loaded from the archive.
1251 if (mod_entry != NULL && mod_entry->is_patched()) {
1252 return false;
1253 }
1254
1255 if (class_loader.is_null()) {
1256 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1257 // The NULL classloader can load archived class originated from the
1258 // "modules" jimage and the -Xbootclasspath/a. For class from the
1259 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1260 // by the NULL classloader.
1261 if (mod_entry != NULL) {
1262 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1263 // ModuleEntry's location agrees with the archived class' origination.
1264 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1265 return true; // Module class from the "module" jimage
1266 }
1267 }
1268
1269 // If the archived class is not from the "module" jimage, the class can be
1270 // loaded by the NULL classloader if
1271 //
1272 // 1. the class is from the unamed package
1273 // 2. or, the class is not from a module defined in the NULL classloader
1274 // 3. or, the class is from an unamed module
1275 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1276 // the class is from the -Xbootclasspath/a
1277 if (pkg_string == NULL ||
1278 pkg_entry == NULL ||
1279 pkg_entry->in_unnamed_module()) {
1280 assert(mod_entry == NULL ||
1281 mod_entry == loader_data->unnamed_module(),
1282 "the unnamed module is not defined in the classloader");
1283 return true;
1284 }
1285 }
1286 return false;
1287 } else {
1288 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1289 ik, class_loader, pkg_string, pkg_name,
1290 pkg_entry, mod_entry, CHECK_(false));
1291 return res;
1292 }
1293 }
1294
1295 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1296 Handle class_loader,
1297 Handle protection_domain, TRAPS) {
1298
1299 if (ik != NULL) {
1300 Symbol* class_name = ik->name();
1301
1302 bool visible = is_shared_class_visible(
1303 class_name, ik, class_loader, CHECK_NULL);
1304 if (!visible) {
1305 return NULL;
1306 }
1307
1308 // Resolve the superclass and interfaces. They must be the same
1309 // as in dump time, because the layout of <ik> depends on
1310 // the specific layout of ik->super() and ik->local_interfaces().
1311 //
1312 // If unexpected superclass or interfaces are found, we cannot
1313 // load <ik> from the shared archive.
1314
1315 if (ik->super() != NULL) {
1316 Symbol* cn = ik->super()->name();
1317 Klass *s = resolve_super_or_fail(class_name, cn,
1318 class_loader, protection_domain, true, CHECK_NULL);
1319 if (s != ik->super()) {
1320 // The dynamically resolved super class is not the same as the one we used during dump time,
1321 // so we cannot use ik.
1322 return NULL;
1323 } else {
1324 assert(s->is_shared(), "must be");
1325 }
1326 }
1327
1328 Array<Klass*>* interfaces = ik->local_interfaces();
1329 int num_interfaces = interfaces->length();
1330 for (int index = 0; index < num_interfaces; index++) {
1331 Klass* k = interfaces->at(index);
1332 Symbol* name = k->name();
1333 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1334 if (k != i) {
1335 // The dynamically resolved interface class is not the same as the one we used during dump time,
1336 // so we cannot use ik.
1337 return NULL;
1338 } else {
1339 assert(i->is_shared(), "must be");
1340 }
1341 }
1342
1343 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1344 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1345 if (new_ik != NULL) {
1346 // The class is changed by CFLH. Return the new class. The shared class is
1347 // not used.
1348 return new_ik;
1349 }
1350
1351 // Adjust methods to recover missing data. They need addresses for
1352 // interpreter entry points and their default native method address
1353 // must be reset.
1354
1355 // Updating methods must be done under a lock so multiple
1356 // threads don't update these in parallel
1357 //
1358 // Shared classes are all currently loaded by either the bootstrap or
1359 // internal parallel class loaders, so this will never cause a deadlock
1360 // on a custom class loader lock.
1361
1362 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1363 {
1364 HandleMark hm(THREAD);
1365 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1366 check_loader_lock_contention(lockObject, THREAD);
1367 ObjectLocker ol(lockObject, THREAD, true);
1368 // prohibited package check assumes all classes loaded from archive call
1369 // restore_unshareable_info which calls ik->set_package()
1370 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1371 }
1372
1373 ik->print_class_load_logging(loader_data, NULL, NULL);
1374
1375 // For boot loader, ensure that GetSystemPackage knows that a class in this
1376 // package was loaded.
1377 if (class_loader.is_null()) {
1378 int path_index = ik->shared_classpath_index();
1379 ResourceMark rm;
1380 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1381 }
1382
1383 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1384 // Only dump the classes that can be stored into CDS archive
1385 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1386 ResourceMark rm(THREAD);
1387 classlist_file->print_cr("%s", ik->name()->as_C_string());
1388 classlist_file->flush();
1389 }
1390 }
1391
1392 // notify a class loaded from shared object
1393 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1394 }
1395
1396 ik->set_has_passed_fingerprint_check(false);
1397 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1398 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1399 uint64_t cds_fp = ik->get_stored_fingerprint();
1400 if (aot_fp != 0 && aot_fp == cds_fp) {
1401 // This class matches with a class saved in an AOT library
1402 ik->set_has_passed_fingerprint_check(true);
1403 } else {
1404 ResourceMark rm;
1405 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1406 }
1407 }
1408 return ik;
1409 }
1410 #endif // INCLUDE_CDS
1411
1412 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1413
1414 if (class_loader.is_null()) {
1415 ResourceMark rm;
1416 PackageEntry* pkg_entry = NULL;
1417 bool search_only_bootloader_append = false;
1418 ClassLoaderData *loader_data = class_loader_data(class_loader);
1419
1420 // Find the package in the boot loader's package entry table.
1421 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1422 if (pkg_name != NULL) {
1423 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1424 }
1425
1426 // Prior to attempting to load the class, enforce the boot loader's
1427 // visibility boundaries.
1428 if (!Universe::is_module_initialized()) {
1429 // During bootstrapping, prior to module initialization, any
1430 // class attempting to be loaded must be checked against the
1431 // java.base packages in the boot loader's PackageEntryTable.
1432 // No class outside of java.base is allowed to be loaded during
1433 // this bootstrapping window.
1434 if (!DumpSharedSpaces) {
1435 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1436 // Class is either in the unnamed package or in
1437 // a named package within the unnamed module. Either
1438 // case is outside of java.base, do not attempt to
1439 // load the class post java.base definition. If
1440 // java.base has not been defined, let the class load
1441 // and its package will be checked later by
1442 // ModuleEntryTable::verify_javabase_packages.
1443 if (ModuleEntryTable::javabase_defined()) {
1444 return NULL;
1445 }
1446 } else {
1447 // Check that the class' package is defined within java.base.
1448 ModuleEntry* mod_entry = pkg_entry->module();
1449 Symbol* mod_entry_name = mod_entry->name();
1450 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1451 return NULL;
1452 }
1453 }
1454 }
1455 } else {
1456 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1457 // After the module system has been initialized, check if the class'
1458 // package is in a module defined to the boot loader.
1459 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1460 // Class is either in the unnamed package, in a named package
1461 // within a module not defined to the boot loader or in a
1462 // a named package within the unnamed module. In all cases,
1463 // limit visibility to search for the class only in the boot
1464 // loader's append path.
1465 search_only_bootloader_append = true;
1466 }
1467 }
1468
1469 // Prior to bootstrapping's module initialization, never load a class outside
1470 // of the boot loader's module path
1471 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1472 !search_only_bootloader_append,
1473 "Attempt to load a class outside of boot loader's module path");
1474
1475 // Search the shared system dictionary for classes preloaded into the
1476 // shared spaces.
1477 InstanceKlass* k = NULL;
1478 {
1479 #if INCLUDE_CDS
1480 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1481 k = load_shared_class(class_name, class_loader, THREAD);
1482 #endif
1483 }
1484
1485 if (k == NULL) {
1486 // Use VM class loader
1487 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1488 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1489 }
1490
1491 // find_or_define_instance_class may return a different InstanceKlass
1492 if (k != NULL) {
1493 InstanceKlass* defined_k =
1494 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1495 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1496 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1497 assert(defined_k != NULL, "Should have a klass if there's no exception");
1498 loader_data->add_to_deallocate_list(k);
1499 k = defined_k;
1500 } else if (HAS_PENDING_EXCEPTION) {
1501 loader_data->add_to_deallocate_list(k);
1502 return NULL;
1503 }
1504 }
1505 return k;
1506 } else {
1507 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1508 ResourceMark rm(THREAD);
1509
1510 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1511 JavaThread* jt = (JavaThread*) THREAD;
1512
1513 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1514 ClassLoader::perf_app_classload_selftime(),
1515 ClassLoader::perf_app_classload_count(),
1516 jt->get_thread_stat()->perf_recursion_counts_addr(),
1517 jt->get_thread_stat()->perf_timers_addr(),
1518 PerfClassTraceTime::CLASS_LOAD);
1519
1520 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1521 // Translate to external class name format, i.e., convert '/' chars to '.'
1522 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1523
1524 JavaValue result(T_OBJECT);
1525
1526 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1527
1528 // Call public unsynchronized loadClass(String) directly for all class loaders
1529 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1530 // acquire a class-name based lock rather than the class loader object lock.
1531 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1532 // so the call to loadClassInternal() was not required.
1533 //
1534 // UnsyncloadClass flag means both call loadClass(String) and do
1535 // not acquire the class loader lock even for class loaders that are
1536 // not parallelCapable. This was a risky transitional
1537 // flag for diagnostic purposes only. It is risky to call
1538 // custom class loaders without synchronization.
1539 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1540 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1541 // Do NOT assume this will be supported in future releases.
1542 //
1543 // Added MustCallLoadClassInternal in case we discover in the field
1544 // a customer that counts on this call
1545 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1546 JavaCalls::call_special(&result,
1547 class_loader,
1548 spec_klass,
1549 vmSymbols::loadClassInternal_name(),
1550 vmSymbols::string_class_signature(),
1551 string,
1552 CHECK_NULL);
1553 } else {
1554 JavaCalls::call_virtual(&result,
1555 class_loader,
1556 spec_klass,
1557 vmSymbols::loadClass_name(),
1558 vmSymbols::string_class_signature(),
1559 string,
1560 CHECK_NULL);
1561 }
1562
1563 assert(result.get_type() == T_OBJECT, "just checking");
1564 oop obj = (oop) result.get_jobject();
1565
1566 // Primitive classes return null since forName() can not be
1567 // used to obtain any of the Class objects representing primitives or void
1568 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1569 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1570 // For user defined Java class loaders, check that the name returned is
1571 // the same as that requested. This check is done for the bootstrap
1572 // loader when parsing the class file.
1573 if (class_name == k->name()) {
1574 return k;
1575 }
1576 }
1577 // Class is not found or has the wrong name, return NULL
1578 return NULL;
1579 }
1580 }
1581
1582 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1583
1584 HandleMark hm(THREAD);
1585 ClassLoaderData* loader_data = k->class_loader_data();
1586 Handle class_loader_h(THREAD, loader_data->class_loader());
1587
1588 // for bootstrap and other parallel classloaders don't acquire lock,
1589 // use placeholder token
1590 // If a parallelCapable class loader calls define_instance_class instead of
1591 // find_or_define_instance_class to get here, we have a timing
1592 // hole with systemDictionary updates and check_constraints
1593 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1594 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1595 compute_loader_lock_object(class_loader_h, THREAD)),
1596 "define called without lock");
1597 }
1598
1599 // Check class-loading constraints. Throw exception if violation is detected.
1600 // Grabs and releases SystemDictionary_lock
1601 // The check_constraints/find_class call and update_dictionary sequence
1602 // must be "atomic" for a specific class/classloader pair so we never
1603 // define two different instanceKlasses for that class/classloader pair.
1604 // Existing classloaders will call define_instance_class with the
1605 // classloader lock held
1606 // Parallel classloaders will call find_or_define_instance_class
1607 // which will require a token to perform the define class
1608 Symbol* name_h = k->name();
1609 Dictionary* dictionary = loader_data->dictionary();
1610 unsigned int d_hash = dictionary->compute_hash(name_h);
1611 int d_index = dictionary->hash_to_index(d_hash);
1612 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1613
1614 // Register class just loaded with class loader (placed in Vector)
1615 // Note we do this before updating the dictionary, as this can
1616 // fail with an OutOfMemoryError (if it does, we will *not* put this
1617 // class in the dictionary and will not update the class hierarchy).
1618 // JVMTI FollowReferences needs to find the classes this way.
1619 if (k->class_loader() != NULL) {
1620 methodHandle m(THREAD, Universe::loader_addClass_method());
1621 JavaValue result(T_VOID);
1622 JavaCallArguments args(class_loader_h);
1623 args.push_oop(Handle(THREAD, k->java_mirror()));
1624 JavaCalls::call(&result, m, &args, CHECK);
1625 }
1626
1627 // Add the new class. We need recompile lock during update of CHA.
1628 {
1629 unsigned int p_hash = placeholders()->compute_hash(name_h);
1630 int p_index = placeholders()->hash_to_index(p_hash);
1631
1632 MutexLocker mu_r(Compile_lock, THREAD);
1633
1634 // Add to class hierarchy, initialize vtables, and do possible
1635 // deoptimizations.
1636 add_to_hierarchy(k, CHECK); // No exception, but can block
1637
1638 // Add to systemDictionary - so other classes can see it.
1639 // Grabs and releases SystemDictionary_lock
1640 update_dictionary(d_index, d_hash, p_index, p_hash,
1641 k, class_loader_h, THREAD);
1642 }
1643 k->eager_initialize(THREAD);
1644
1645 // notify jvmti
1646 if (JvmtiExport::should_post_class_load()) {
1647 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1648 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1649
1650 }
1651 class_define_event(k, loader_data);
1652 }
1653
1654 // Support parallel classloading
1655 // All parallel class loaders, including bootstrap classloader
1656 // lock a placeholder entry for this class/class_loader pair
1657 // to allow parallel defines of different classes for this class loader
1658 // With AllowParallelDefine flag==true, in case they do not synchronize around
1659 // FindLoadedClass/DefineClass, calls, we check for parallel
1660 // loading for them, wait if a defineClass is in progress
1661 // and return the initial requestor's results
1662 // This flag does not apply to the bootstrap classloader.
1663 // With AllowParallelDefine flag==false, call through to define_instance_class
1664 // which will throw LinkageError: duplicate class definition.
1665 // False is the requested default.
1666 // For better performance, the class loaders should synchronize
1667 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1668 // potentially waste time reading and parsing the bytestream.
1669 // Note: VM callers should ensure consistency of k/class_name,class_loader
1670 // Be careful when modifying this code: once you have run
1671 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1672 // you need to find_and_remove it before returning.
1673 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1674 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1675 InstanceKlass* k, TRAPS) {
1676
1677 Symbol* name_h = k->name(); // passed in class_name may be null
1678 ClassLoaderData* loader_data = class_loader_data(class_loader);
1679 Dictionary* dictionary = loader_data->dictionary();
1680
1681 unsigned int d_hash = dictionary->compute_hash(name_h);
1682 int d_index = dictionary->hash_to_index(d_hash);
1683
1684 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1685 unsigned int p_hash = placeholders()->compute_hash(name_h);
1686 int p_index = placeholders()->hash_to_index(p_hash);
1687 PlaceholderEntry* probe;
1688
1689 {
1690 MutexLocker mu(SystemDictionary_lock, THREAD);
1691 // First check if class already defined
1692 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1693 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1694 if (check != NULL) {
1695 return check;
1696 }
1697 }
1698
1699 // Acquire define token for this class/classloader
1700 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1701 // Wait if another thread defining in parallel
1702 // All threads wait - even those that will throw duplicate class: otherwise
1703 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1704 // if other thread has not finished updating dictionary
1705 while (probe->definer() != NULL) {
1706 SystemDictionary_lock->wait();
1707 }
1708 // Only special cases allow parallel defines and can use other thread's results
1709 // Other cases fall through, and may run into duplicate defines
1710 // caught by finding an entry in the SystemDictionary
1711 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1712 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1713 SystemDictionary_lock->notify_all();
1714 #ifdef ASSERT
1715 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1716 assert(check != NULL, "definer missed recording success");
1717 #endif
1718 return probe->instance_klass();
1719 } else {
1720 // This thread will define the class (even if earlier thread tried and had an error)
1721 probe->set_definer(THREAD);
1722 }
1723 }
1724
1725 define_instance_class(k, THREAD);
1726
1727 Handle linkage_exception = Handle(); // null handle
1728
1729 // definer must notify any waiting threads
1730 {
1731 MutexLocker mu(SystemDictionary_lock, THREAD);
1732 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1733 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1734 if (probe != NULL) {
1735 if (HAS_PENDING_EXCEPTION) {
1736 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1737 CLEAR_PENDING_EXCEPTION;
1738 } else {
1739 probe->set_instance_klass(k);
1740 }
1741 probe->set_definer(NULL);
1742 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1743 SystemDictionary_lock->notify_all();
1744 }
1745 }
1746
1747 // Can't throw exception while holding lock due to rank ordering
1748 if (linkage_exception() != NULL) {
1749 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1750 }
1751
1752 return k;
1753 }
1754
1755 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1756 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1757 if (class_loader.is_null()) {
1758 return Handle(THREAD, _system_loader_lock_obj);
1759 } else {
1760 return class_loader;
1761 }
1762 }
1763
1764 // This method is added to check how often we have to wait to grab loader
1765 // lock. The results are being recorded in the performance counters defined in
1766 // ClassLoader::_sync_systemLoaderLockContentionRate and
1767 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1768 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1769 if (!UsePerfData) {
1770 return;
1771 }
1772
1773 assert(!loader_lock.is_null(), "NULL lock object");
1774
1775 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1776 == ObjectSynchronizer::owner_other) {
1777 // contention will likely happen, so increment the corresponding
1778 // contention counter.
1779 if (loader_lock() == _system_loader_lock_obj) {
1780 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1781 } else {
1782 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1783 }
1784 }
1785 }
1786
1787 // ----------------------------------------------------------------------------
1788 // Lookup
1789
1790 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1791 Symbol* class_name,
1792 Dictionary* dictionary) {
1793 assert_locked_or_safepoint(SystemDictionary_lock);
1794 return dictionary->find_class(index, hash, class_name);
1795 }
1796
1797
1798 // Basic find on classes in the midst of being loaded
1799 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1800 ClassLoaderData* loader_data) {
1801 assert_locked_or_safepoint(SystemDictionary_lock);
1802 unsigned int p_hash = placeholders()->compute_hash(class_name);
1803 int p_index = placeholders()->hash_to_index(p_hash);
1804 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1805 }
1806
1807
1808 // Used for assertions and verification only
1809 // Precalculating the hash and index is an optimization because there are many lookups
1810 // before adding the class.
1811 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1812 assert_locked_or_safepoint(SystemDictionary_lock);
1813 #ifndef ASSERT
1814 guarantee(VerifyBeforeGC ||
1815 VerifyDuringGC ||
1816 VerifyBeforeExit ||
1817 VerifyDuringStartup ||
1818 VerifyAfterGC, "too expensive");
1819 #endif
1820
1821 Dictionary* dictionary = loader_data->dictionary();
1822 unsigned int d_hash = dictionary->compute_hash(class_name);
1823 int d_index = dictionary->hash_to_index(d_hash);
1824 return find_class(d_index, d_hash, class_name, dictionary);
1825 }
1826
1827
1828 // ----------------------------------------------------------------------------
1829 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1830 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1831 // before a new class is used.
1832
1833 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1834 assert(k != NULL, "just checking");
1835 assert_locked_or_safepoint(Compile_lock);
1836
1837 // Link into hierachy. Make sure the vtables are initialized before linking into
1838 k->append_to_sibling_list(); // add to superklass/sibling list
1839 k->process_interfaces(THREAD); // handle all "implements" declarations
1840 k->set_init_state(InstanceKlass::loaded);
1841 // Now flush all code that depended on old class hierarchy.
1842 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1843 // Also, first reinitialize vtable because it may have gotten out of synch
1844 // while the new class wasn't connected to the class hierarchy.
1845 CodeCache::flush_dependents_on(k);
1846 }
1847
1848 // ----------------------------------------------------------------------------
1849 // GC support
1850
1851 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1852 roots_oops_do(blk, NULL);
1853 }
1854
1855
1856 #ifdef ASSERT
1857 class VerifySDReachableAndLiveClosure : public OopClosure {
1858 private:
1859 BoolObjectClosure* _is_alive;
1860
1861 template <class T> void do_oop_work(T* p) {
1862 oop obj = oopDesc::load_decode_heap_oop(p);
1863 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1864 }
1865
1866 public:
1867 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1868
1869 virtual void do_oop(oop* p) { do_oop_work(p); }
1870 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1871 };
1872 #endif
1873
1874 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1875 // Note: anonymous classes are not in the SD.
1876 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1877 GCTimer* gc_timer,
1878 bool do_cleaning) {
1879
1880
1881 bool unloading_occurred;
1882 {
1883 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1884
1885 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1886 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1887 do_cleaning);
1888 }
1889
1890 if (unloading_occurred) {
1891 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1892 constraints()->purge_loader_constraints();
1893 resolution_errors()->purge_resolution_errors();
1894 }
1895
1896 {
1897 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1898 // Oops referenced by the protection domain cache table may get unreachable independently
1899 // of the class loader (eg. cached protection domain oops). So we need to
1900 // explicitly unlink them here.
1901 _pd_cache_table->unlink(is_alive);
1902
1903 #ifdef ASSERT
1904 VerifySDReachableAndLiveClosure cl(is_alive);
1905 _pd_cache_table->oops_do(&cl);
1906 #endif
1907 }
1908
1909 if (do_cleaning) {
1910 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1911 ResolvedMethodTable::unlink(is_alive);
1912 }
1913
1914 return unloading_occurred;
1915 }
1916
1917 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1918 strong->do_oop(&_java_system_loader);
1919 strong->do_oop(&_system_loader_lock_obj);
1920 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1921
1922 // Do strong roots marking if the closures are the same.
1923 if (strong == weak || !ClassUnloading) {
1924 // Only the protection domain oops contain references into the heap. Iterate
1925 // over all of them.
1926 _pd_cache_table->oops_do(strong);
1927 } else {
1928 if (weak != NULL) {
1929 _pd_cache_table->oops_do(weak);
1930 }
1931 }
1932
1933 // Visit extra methods
1934 invoke_method_table()->oops_do(strong);
1935
1936 if (weak != NULL) {
1937 ResolvedMethodTable::oops_do(weak);
1938 }
1939 }
1940
1941 void SystemDictionary::oops_do(OopClosure* f) {
1942 f->do_oop(&_java_system_loader);
1943 f->do_oop(&_system_loader_lock_obj);
1944 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1945
1946 // Only the protection domain oops contain references into the heap. Iterate
1947 // over all of them.
1948 _pd_cache_table->oops_do(f);
1949
1950 // Visit extra methods
1951 invoke_method_table()->oops_do(f);
1952
1953 ResolvedMethodTable::oops_do(f);
1954 }
1955
1956 // CDS: scan and relocate all classes in the system dictionary.
1957 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1958 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1959 }
1960
1961 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1962 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1963 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1964 it->push(well_known_klass_addr((WKID)id));
1965 }
1966 }
1967
1968 void SystemDictionary::methods_do(void f(Method*)) {
1969 // Walk methods in loaded classes
1970 ClassLoaderDataGraph::methods_do(f);
1971 // Walk method handle intrinsics
1972 invoke_method_table()->methods_do(f);
1973 }
1974
1975 void SystemDictionary::remove_classes_in_error_state() {
1976 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1977 }
1978
1979 // ----------------------------------------------------------------------------
1980 // Lazily load klasses
1981
1982 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1983 // if multiple threads calling this function, only one thread will load
1984 // the class. The other threads will find the loaded version once the
1985 // class is loaded.
1986 Klass* aos = _abstract_ownable_synchronizer_klass;
1987 if (aos == NULL) {
1988 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1989 // Force a fence to prevent any read before the write completes
1990 OrderAccess::fence();
1991 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1992 }
1993 }
1994
1995 // ----------------------------------------------------------------------------
1996 // Initialization
1997
1998 void SystemDictionary::initialize(TRAPS) {
1999 // Allocate arrays
2000 _placeholders = new PlaceholderTable(_placeholder_table_size);
2001 _number_of_modifications = 0;
2002 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2003 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2004 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2005 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2006
2007 // Allocate private object used as system class loader lock
2008 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2009 // Initialize basic classes
2010 initialize_preloaded_classes(CHECK);
2011 }
2012
2013 // Compact table of directions on the initialization of klasses:
2014 static const short wk_init_info[] = {
2015 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2016 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2017 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2018 | (int)SystemDictionary::option ),
2019 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2020 #undef WK_KLASS_INIT_INFO
2021 0
2022 };
2023
2024 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2025 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2026 int info = wk_init_info[id - FIRST_WKID];
2027 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2028 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2029 InstanceKlass** klassp = &_well_known_klasses[id];
2030
2031 bool must_load;
2032 #if INCLUDE_JVMCI
2033 if (EnableJVMCI) {
2034 // If JVMCI is enabled we require its classes to be found.
2035 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2036 } else
2037 #endif
2038 {
2039 must_load = (init_opt < SystemDictionary::Opt);
2040 }
2041
2042 if ((*klassp) == NULL) {
2043 Klass* k;
2044 if (must_load) {
2045 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2046 } else {
2047 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2048 }
2049 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2050 }
2051 return ((*klassp) != NULL);
2052 }
2053
2054 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2055 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2056 for (int id = (int)start_id; id < (int)limit_id; id++) {
2057 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2058 int info = wk_init_info[id - FIRST_WKID];
2059 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2060 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2061
2062 initialize_wk_klass((WKID)id, opt, CHECK);
2063 }
2064
2065 // move the starting value forward to the limit:
2066 start_id = limit_id;
2067 }
2068
2069 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2070 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2071
2072 // Create the ModuleEntry for java.base. This call needs to be done here,
2073 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2074 ClassLoader::classLoader_init2(CHECK);
2075
2076 // Preload commonly used klasses
2077 WKID scan = FIRST_WKID;
2078 // first do Object, then String, Class
2079 #if INCLUDE_CDS
2080 if (UseSharedSpaces) {
2081 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2082 // Initialize the constant pool for the Object_class
2083 Object_klass()->constants()->restore_unshareable_info(CHECK);
2084 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2085 } else
2086 #endif
2087 {
2088 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2089 }
2090
2091 // Calculate offsets for String and Class classes since they are loaded and
2092 // can be used after this point.
2093 java_lang_String::compute_offsets();
2094 java_lang_Class::compute_offsets();
2095
2096 // Fixup mirrors for classes loaded before java.lang.Class.
2097 // These calls iterate over the objects currently in the perm gen
2098 // so calling them at this point is matters (not before when there
2099 // are fewer objects and not later after there are more objects
2100 // in the perm gen.
2101 Universe::initialize_basic_type_mirrors(CHECK);
2102 Universe::fixup_mirrors(CHECK);
2103
2104 // do a bunch more:
2105 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2106
2107 // Preload ref klasses and set reference types
2108 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2109 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2110
2111 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2112 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2113 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2114 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2115 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2116
2117 // JSR 292 classes
2118 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2119 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2120 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2121 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2122 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2123
2124 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2125 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2126 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2127 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2128 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2129 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2130 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2131 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2132 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2133 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2134
2135 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2136 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2137 _has_loadClassInternal = (method != NULL);
2138 }
2139 { // Compute whether we should use checkPackageAccess or NOT
2140 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2141 _has_checkPackageAccess = (method != NULL);
2142 }
2143 }
2144
2145 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2146 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2147 BasicType SystemDictionary::box_klass_type(Klass* k) {
2148 assert(k != NULL, "");
2149 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2150 if (_box_klasses[i] == k)
2151 return (BasicType)i;
2152 }
2153 return T_OBJECT;
2154 }
2155
2156 // Constraints on class loaders. The details of the algorithm can be
2157 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2158 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2159 // that the dictionary needs to maintain a set of contraints that
2160 // must be satisfied by all classes in the dictionary.
2161 // if defining is true, then LinkageError if already in dictionary
2162 // if initiating loader, then ok if InstanceKlass matches existing entry
2163
2164 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2165 InstanceKlass* k,
2166 Handle class_loader, bool defining,
2167 TRAPS) {
2168 const char *linkage_error1 = NULL;
2169 const char *linkage_error2 = NULL;
2170 {
2171 Symbol* name = k->name();
2172 ClassLoaderData *loader_data = class_loader_data(class_loader);
2173
2174 MutexLocker mu(SystemDictionary_lock, THREAD);
2175
2176 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2177 if (check != NULL) {
2178 // if different InstanceKlass - duplicate class definition,
2179 // else - ok, class loaded by a different thread in parallel,
2180 // we should only have found it if it was done loading and ok to use
2181 // dictionary only holds instance classes, placeholders
2182 // also holds array classes
2183
2184 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2185 if ((defining == true) || (k != check)) {
2186 linkage_error1 = "loader (instance of ";
2187 linkage_error2 = "): attempted duplicate class definition for name: \"";
2188 } else {
2189 return;
2190 }
2191 }
2192
2193 #ifdef ASSERT
2194 Symbol* ph_check = find_placeholder(name, loader_data);
2195 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2196 #endif
2197
2198 if (linkage_error1 == NULL) {
2199 if (constraints()->check_or_update(k, class_loader, name) == false) {
2200 linkage_error1 = "loader constraint violation: loader (instance of ";
2201 linkage_error2 = ") previously initiated loading for a different type with name \"";
2202 }
2203 }
2204 }
2205
2206 // Throw error now if needed (cannot throw while holding
2207 // SystemDictionary_lock because of rank ordering)
2208
2209 if (linkage_error1) {
2210 ResourceMark rm(THREAD);
2211 const char* class_loader_name = loader_name(class_loader());
2212 char* type_name = k->name()->as_C_string();
2213 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2214 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2215 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2216 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2217 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2218 }
2219 }
2220
2221
2222 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2223 // have been called.
2224 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2225 int p_index, unsigned int p_hash,
2226 InstanceKlass* k,
2227 Handle class_loader,
2228 TRAPS) {
2229 // Compile_lock prevents systemDictionary updates during compilations
2230 assert_locked_or_safepoint(Compile_lock);
2231 Symbol* name = k->name();
2232 ClassLoaderData *loader_data = class_loader_data(class_loader);
2233
2234 {
2235 MutexLocker mu1(SystemDictionary_lock, THREAD);
2236
2237 // See whether biased locking is enabled and if so set it for this
2238 // klass.
2239 // Note that this must be done past the last potential blocking
2240 // point / safepoint. We enable biased locking lazily using a
2241 // VM_Operation to iterate the SystemDictionary and installing the
2242 // biasable mark word into each InstanceKlass's prototype header.
2243 // To avoid race conditions where we accidentally miss enabling the
2244 // optimization for one class in the process of being added to the
2245 // dictionary, we must not safepoint after the test of
2246 // BiasedLocking::enabled().
2247 if (UseBiasedLocking && BiasedLocking::enabled()) {
2248 // Set biased locking bit for all loaded classes; it will be
2249 // cleared if revocation occurs too often for this type
2250 // NOTE that we must only do this when the class is initally
2251 // defined, not each time it is referenced from a new class loader
2252 if (k->class_loader() == class_loader()) {
2253 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2254 }
2255 }
2256
2257 // Make a new dictionary entry.
2258 Dictionary* dictionary = loader_data->dictionary();
2259 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2260 if (sd_check == NULL) {
2261 dictionary->add_klass(d_index, d_hash, name, k);
2262 notice_modification();
2263 }
2264 #ifdef ASSERT
2265 sd_check = find_class(d_index, d_hash, name, dictionary);
2266 assert (sd_check != NULL, "should have entry in dictionary");
2267 // Note: there may be a placeholder entry: for circularity testing
2268 // or for parallel defines
2269 #endif
2270 SystemDictionary_lock->notify_all();
2271 }
2272 }
2273
2274
2275 // Try to find a class name using the loader constraints. The
2276 // loader constraints might know about a class that isn't fully loaded
2277 // yet and these will be ignored.
2278 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2279 Symbol* class_name, Handle class_loader, TRAPS) {
2280
2281 // First see if it has been loaded directly.
2282 // Force the protection domain to be null. (This removes protection checks.)
2283 Handle no_protection_domain;
2284 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2285 no_protection_domain, CHECK_NULL);
2286 if (klass != NULL)
2287 return klass;
2288
2289 // Now look to see if it has been loaded elsewhere, and is subject to
2290 // a loader constraint that would require this loader to return the
2291 // klass that is already loaded.
2292 if (FieldType::is_array(class_name)) {
2293 // For array classes, their Klass*s are not kept in the
2294 // constraint table. The element Klass*s are.
2295 FieldArrayInfo fd;
2296 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2297 if (t != T_OBJECT) {
2298 klass = Universe::typeArrayKlassObj(t);
2299 } else {
2300 MutexLocker mu(SystemDictionary_lock, THREAD);
2301 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2302 }
2303 // If element class already loaded, allocate array klass
2304 if (klass != NULL) {
2305 klass = klass->array_klass_or_null(fd.dimension());
2306 }
2307 } else {
2308 MutexLocker mu(SystemDictionary_lock, THREAD);
2309 // Non-array classes are easy: simply check the constraint table.
2310 klass = constraints()->find_constrained_klass(class_name, class_loader);
2311 }
2312
2313 return klass;
2314 }
2315
2316
2317 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2318 Handle class_loader1,
2319 Handle class_loader2,
2320 Thread* THREAD) {
2321 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2322 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2323
2324 Symbol* constraint_name = NULL;
2325 if (!FieldType::is_array(class_name)) {
2326 constraint_name = class_name;
2327 } else {
2328 // For array classes, their Klass*s are not kept in the
2329 // constraint table. The element classes are.
2330 FieldArrayInfo fd;
2331 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2332 // primitive types always pass
2333 if (t != T_OBJECT) {
2334 return true;
2335 } else {
2336 constraint_name = fd.object_key();
2337 }
2338 }
2339
2340 Dictionary* dictionary1 = loader_data1->dictionary();
2341 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2342 int d_index1 = dictionary1->hash_to_index(d_hash1);
2343
2344 Dictionary* dictionary2 = loader_data2->dictionary();
2345 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2346 int d_index2 = dictionary2->hash_to_index(d_hash2);
2347
2348 {
2349 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2350 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2351 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2352 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2353 klass2, class_loader2);
2354 }
2355 }
2356
2357 // Add entry to resolution error table to record the error when the first
2358 // attempt to resolve a reference to a class has failed.
2359 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2360 Symbol* error, Symbol* message) {
2361 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2362 int index = resolution_errors()->hash_to_index(hash);
2363 {
2364 MutexLocker ml(SystemDictionary_lock, Thread::current());
2365 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2366 }
2367 }
2368
2369 // Delete a resolution error for RedefineClasses for a constant pool is going away
2370 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2371 resolution_errors()->delete_entry(pool);
2372 }
2373
2374 // Lookup resolution error table. Returns error if found, otherwise NULL.
2375 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2376 Symbol** message) {
2377 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2378 int index = resolution_errors()->hash_to_index(hash);
2379 {
2380 MutexLocker ml(SystemDictionary_lock, Thread::current());
2381 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2382 if (entry != NULL) {
2383 *message = entry->message();
2384 return entry->error();
2385 } else {
2386 return NULL;
2387 }
2388 }
2389 }
2390
2391
2392 // Signature constraints ensure that callers and callees agree about
2393 // the meaning of type names in their signatures. This routine is the
2394 // intake for constraints. It collects them from several places:
2395 //
2396 // * LinkResolver::resolve_method (if check_access is true) requires
2397 // that the resolving class (the caller) and the defining class of
2398 // the resolved method (the callee) agree on each type in the
2399 // method's signature.
2400 //
2401 // * LinkResolver::resolve_interface_method performs exactly the same
2402 // checks.
2403 //
2404 // * LinkResolver::resolve_field requires that the constant pool
2405 // attempting to link to a field agree with the field's defining
2406 // class about the type of the field signature.
2407 //
2408 // * klassVtable::initialize_vtable requires that, when a class
2409 // overrides a vtable entry allocated by a superclass, that the
2410 // overriding method (i.e., the callee) agree with the superclass
2411 // on each type in the method's signature.
2412 //
2413 // * klassItable::initialize_itable requires that, when a class fills
2414 // in its itables, for each non-abstract method installed in an
2415 // itable, the method (i.e., the callee) agree with the interface
2416 // on each type in the method's signature.
2417 //
2418 // All those methods have a boolean (check_access, checkconstraints)
2419 // which turns off the checks. This is used from specialized contexts
2420 // such as bootstrapping, dumping, and debugging.
2421 //
2422 // No direct constraint is placed between the class and its
2423 // supertypes. Constraints are only placed along linked relations
2424 // between callers and callees. When a method overrides or implements
2425 // an abstract method in a supertype (superclass or interface), the
2426 // constraints are placed as if the supertype were the caller to the
2427 // overriding method. (This works well, since callers to the
2428 // supertype have already established agreement between themselves and
2429 // the supertype.) As a result of all this, a class can disagree with
2430 // its supertype about the meaning of a type name, as long as that
2431 // class neither calls a relevant method of the supertype, nor is
2432 // called (perhaps via an override) from the supertype.
2433 //
2434 //
2435 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2436 //
2437 // Make sure all class components (including arrays) in the given
2438 // signature will be resolved to the same class in both loaders.
2439 // Returns the name of the type that failed a loader constraint check, or
2440 // NULL if no constraint failed. No exception except OOME is thrown.
2441 // Arrays are not added to the loader constraint table, their elements are.
2442 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2443 Handle loader1, Handle loader2,
2444 bool is_method, TRAPS) {
2445 // Nothing to do if loaders are the same.
2446 if (loader1() == loader2()) {
2447 return NULL;
2448 }
2449
2450 SignatureStream sig_strm(signature, is_method);
2451 while (!sig_strm.is_done()) {
2452 if (sig_strm.is_object()) {
2453 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2454 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2455 return sig;
2456 }
2457 }
2458 sig_strm.next();
2459 }
2460 return NULL;
2461 }
2462
2463
2464 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2465 Symbol* signature,
2466 TRAPS) {
2467 methodHandle empty;
2468 assert(MethodHandles::is_signature_polymorphic(iid) &&
2469 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2470 iid != vmIntrinsics::_invokeGeneric,
2471 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2472
2473 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2474 int index = invoke_method_table()->hash_to_index(hash);
2475 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2476 methodHandle m;
2477 if (spe == NULL || spe->method() == NULL) {
2478 spe = NULL;
2479 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2480 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2481 if (!Arguments::is_interpreter_only()) {
2482 // Generate a compiled form of the MH intrinsic.
2483 AdapterHandlerLibrary::create_native_wrapper(m);
2484 // Check if have the compiled code.
2485 if (!m->has_compiled_code()) {
2486 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2487 "Out of space in CodeCache for method handle intrinsic", empty);
2488 }
2489 }
2490 // Now grab the lock. We might have to throw away the new method,
2491 // if a racing thread has managed to install one at the same time.
2492 {
2493 MutexLocker ml(SystemDictionary_lock, THREAD);
2494 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2495 if (spe == NULL)
2496 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2497 if (spe->method() == NULL)
2498 spe->set_method(m());
2499 }
2500 }
2501
2502 assert(spe != NULL && spe->method() != NULL, "");
2503 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2504 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2505 "MH intrinsic invariant");
2506 return spe->method();
2507 }
2508
2509 // Helper for unpacking the return value from linkMethod and linkCallSite.
2510 static methodHandle unpack_method_and_appendix(Handle mname,
2511 Klass* accessing_klass,
2512 objArrayHandle appendix_box,
2513 Handle* appendix_result,
2514 TRAPS) {
2515 methodHandle empty;
2516 if (mname.not_null()) {
2517 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2518 if (m != NULL) {
2519 oop appendix = appendix_box->obj_at(0);
2520 if (TraceMethodHandles) {
2521 #ifndef PRODUCT
2522 ttyLocker ttyl;
2523 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2524 m->print();
2525 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2526 tty->cr();
2527 #endif //PRODUCT
2528 }
2529 (*appendix_result) = Handle(THREAD, appendix);
2530 // the target is stored in the cpCache and if a reference to this
2531 // MethodName is dropped we need a way to make sure the
2532 // class_loader containing this method is kept alive.
2533 // FIXME: the appendix might also preserve this dependency.
2534 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2535 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2536 return methodHandle(THREAD, m);
2537 }
2538 }
2539 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2540 return empty;
2541 }
2542
2543 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2544 Symbol* name,
2545 Symbol* signature,
2546 Klass* accessing_klass,
2547 Handle *appendix_result,
2548 Handle *method_type_result,
2549 TRAPS) {
2550 methodHandle empty;
2551 assert(THREAD->can_call_java() ,"");
2552 Handle method_type =
2553 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2554
2555 int ref_kind = JVM_REF_invokeVirtual;
2556 oop name_oop = StringTable::intern(name, CHECK_(empty));
2557 Handle name_str (THREAD, name_oop);
2558 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2559 assert(appendix_box->obj_at(0) == NULL, "");
2560
2561 // This should not happen. JDK code should take care of that.
2562 if (accessing_klass == NULL || method_type.is_null()) {
2563 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2564 }
2565
2566 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2567 JavaCallArguments args;
2568 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2569 args.push_int(ref_kind);
2570 args.push_oop(Handle(THREAD, klass->java_mirror()));
2571 args.push_oop(name_str);
2572 args.push_oop(method_type);
2573 args.push_oop(appendix_box);
2574 JavaValue result(T_OBJECT);
2575 JavaCalls::call_static(&result,
2576 SystemDictionary::MethodHandleNatives_klass(),
2577 vmSymbols::linkMethod_name(),
2578 vmSymbols::linkMethod_signature(),
2579 &args, CHECK_(empty));
2580 Handle mname(THREAD, (oop) result.get_jobject());
2581 (*method_type_result) = method_type;
2582 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2583 }
2584
2585 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2586 // We must ensure that all class loaders everywhere will reach this class, for any client.
2587 // This is a safe bet for public classes in java.lang, such as Object and String.
2588 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2589 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2590 static bool is_always_visible_class(oop mirror) {
2591 Klass* klass = java_lang_Class::as_Klass(mirror);
2592 if (klass->is_objArray_klass()) {
2593 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2594 }
2595 if (klass->is_typeArray_klass()) {
2596 return true; // primitive array
2597 }
2598 assert(klass->is_instance_klass(), "%s", klass->external_name());
2599 return klass->is_public() &&
2600 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2601 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2602 }
2603
2604 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2605 // signature, as interpreted relative to the given class loader.
2606 // Because of class loader constraints, all method handle usage must be
2607 // consistent with this loader.
2608 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2609 Klass* accessing_klass,
2610 TRAPS) {
2611 Handle empty;
2612 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2613 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2614 int index = invoke_method_table()->hash_to_index(hash);
2615 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2616 if (spe != NULL && spe->method_type() != NULL) {
2617 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2618 return Handle(THREAD, spe->method_type());
2619 } else if (!THREAD->can_call_java()) {
2620 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2621 return Handle(); // do not attempt from within compiler, unless it was cached
2622 }
2623
2624 Handle class_loader, protection_domain;
2625 if (accessing_klass != NULL) {
2626 class_loader = Handle(THREAD, accessing_klass->class_loader());
2627 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2628 }
2629 bool can_be_cached = true;
2630 int npts = ArgumentCount(signature).size();
2631 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2632 int arg = 0;
2633 Handle rt; // the return type from the signature
2634 ResourceMark rm(THREAD);
2635 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2636 oop mirror = NULL;
2637 if (can_be_cached) {
2638 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2639 mirror = ss.as_java_mirror(Handle(), Handle(),
2640 SignatureStream::ReturnNull, CHECK_(empty));
2641 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2642 // Fall back to accessing_klass context.
2643 can_be_cached = false;
2644 }
2645 }
2646 if (!can_be_cached) {
2647 // Resolve, throwing a real error if it doesn't work.
2648 mirror = ss.as_java_mirror(class_loader, protection_domain,
2649 SignatureStream::NCDFError, CHECK_(empty));
2650 }
2651 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2652 if (ss.at_return_type())
2653 rt = Handle(THREAD, mirror);
2654 else
2655 pts->obj_at_put(arg++, mirror);
2656
2657 // Check accessibility.
2658 if (ss.is_object() && accessing_klass != NULL) {
2659 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2660 mirror = NULL; // safety
2661 // Emulate ConstantPool::verify_constant_pool_resolve.
2662 if (sel_klass->is_objArray_klass())
2663 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2664 if (sel_klass->is_instance_klass()) {
2665 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2666 }
2667 }
2668 }
2669 assert(arg == npts, "");
2670
2671 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2672 JavaCallArguments args(Handle(THREAD, rt()));
2673 args.push_oop(pts);
2674 JavaValue result(T_OBJECT);
2675 JavaCalls::call_static(&result,
2676 SystemDictionary::MethodHandleNatives_klass(),
2677 vmSymbols::findMethodHandleType_name(),
2678 vmSymbols::findMethodHandleType_signature(),
2679 &args, CHECK_(empty));
2680 Handle method_type(THREAD, (oop) result.get_jobject());
2681
2682 if (can_be_cached) {
2683 // We can cache this MethodType inside the JVM.
2684 MutexLocker ml(SystemDictionary_lock, THREAD);
2685 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2686 if (spe == NULL)
2687 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2688 if (spe->method_type() == NULL) {
2689 spe->set_method_type(method_type());
2690 }
2691 }
2692
2693 // report back to the caller with the MethodType
2694 return method_type;
2695 }
2696
2697 // Ask Java code to find or construct a method handle constant.
2698 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2699 int ref_kind, //e.g., JVM_REF_invokeVirtual
2700 Klass* callee,
2701 Symbol* name_sym,
2702 Symbol* signature,
2703 TRAPS) {
2704 Handle empty;
2705 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2706 Handle type;
2707 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2708 type = find_method_handle_type(signature, caller, CHECK_(empty));
2709 } else if (caller == NULL) {
2710 // This should not happen. JDK code should take care of that.
2711 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2712 } else {
2713 ResourceMark rm(THREAD);
2714 SignatureStream ss(signature, false);
2715 if (!ss.is_done()) {
2716 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2717 Handle(THREAD, caller->protection_domain()),
2718 SignatureStream::NCDFError, CHECK_(empty));
2719 type = Handle(THREAD, mirror);
2720 ss.next();
2721 if (!ss.is_done()) type = Handle(); // error!
2722 }
2723 }
2724 if (type.is_null()) {
2725 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2726 }
2727
2728 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2729 JavaCallArguments args;
2730 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2731 args.push_int(ref_kind);
2732 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2733 args.push_oop(name);
2734 args.push_oop(type);
2735 JavaValue result(T_OBJECT);
2736 JavaCalls::call_static(&result,
2737 SystemDictionary::MethodHandleNatives_klass(),
2738 vmSymbols::linkMethodHandleConstant_name(),
2739 vmSymbols::linkMethodHandleConstant_signature(),
2740 &args, CHECK_(empty));
2741 return Handle(THREAD, (oop) result.get_jobject());
2742 }
2743
2744 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2745 // name and signature, as interpreted relative to the given class loader.
2746 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2747 Handle bootstrap_specifier,
2748 Symbol* name,
2749 Symbol* type,
2750 Handle *appendix_result,
2751 Handle *method_type_result,
2752 TRAPS) {
2753 methodHandle empty;
2754 Handle bsm, info;
2755 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2756 bsm = bootstrap_specifier;
2757 } else {
2758 assert(bootstrap_specifier->is_objArray(), "");
2759 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2760 int len = args->length();
2761 assert(len >= 1, "");
2762 bsm = Handle(THREAD, args->obj_at(0));
2763 if (len > 1) {
2764 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2765 for (int i = 1; i < len; i++)
2766 args1->obj_at_put(i-1, args->obj_at(i));
2767 info = Handle(THREAD, args1);
2768 }
2769 }
2770 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2771 "caller must supply a valid BSM");
2772
2773 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2774 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2775
2776 // This should not happen. JDK code should take care of that.
2777 if (caller == NULL || method_type.is_null()) {
2778 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2779 }
2780
2781 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2782 assert(appendix_box->obj_at(0) == NULL, "");
2783
2784 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2785 JavaCallArguments args;
2786 args.push_oop(Handle(THREAD, caller->java_mirror()));
2787 args.push_oop(bsm);
2788 args.push_oop(method_name);
2789 args.push_oop(method_type);
2790 args.push_oop(info);
2791 args.push_oop(appendix_box);
2792 JavaValue result(T_OBJECT);
2793 JavaCalls::call_static(&result,
2794 SystemDictionary::MethodHandleNatives_klass(),
2795 vmSymbols::linkCallSite_name(),
2796 vmSymbols::linkCallSite_signature(),
2797 &args, CHECK_(empty));
2798 Handle mname(THREAD, (oop) result.get_jobject());
2799 (*method_type_result) = method_type;
2800 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2801 }
2802
2803 // Protection domain cache table handling
2804
2805 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2806 return _pd_cache_table->get(protection_domain);
2807 }
2808
2809 void SystemDictionary::reorder_dictionary_for_sharing() {
2810 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2811 }
2812
2813 size_t SystemDictionary::count_bytes_for_buckets() {
2814 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2815 }
2816
2817 size_t SystemDictionary::count_bytes_for_table() {
2818 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2819 }
2820
2821 void SystemDictionary::copy_buckets(char* top, char* end) {
2822 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2823 }
2824
2825 void SystemDictionary::copy_table(char* top, char* end) {
2826 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2827 }
2828
2829 // ----------------------------------------------------------------------------
2830 void SystemDictionary::print_shared(outputStream *st) {
2831 shared_dictionary()->print_on(st);
2832 }
2833
2834 void SystemDictionary::print_on(outputStream *st) {
2835 if (shared_dictionary() != NULL) {
2836 st->print_cr("Shared Dictionary");
2837 shared_dictionary()->print_on(st);
2838 st->cr();
2839 }
2840
2841 GCMutexLocker mu(SystemDictionary_lock);
2842
2843 ClassLoaderDataGraph::print_dictionary(st);
2844
2845 // Placeholders
2846 placeholders()->print_on(st);
2847 st->cr();
2848
2849 // loader constraints - print under SD_lock
2850 constraints()->print_on(st);
2851 st->cr();
2852
2853 _pd_cache_table->print_on(st);
2854 st->cr();
2855 }
2856
2857 void SystemDictionary::verify() {
2858 guarantee(constraints() != NULL,
2859 "Verify of loader constraints failed");
2860 guarantee(placeholders()->number_of_entries() >= 0,
2861 "Verify of placeholders failed");
2862
2863 GCMutexLocker mu(SystemDictionary_lock);
2864
2865 // Verify dictionary
2866 ClassLoaderDataGraph::verify_dictionary();
2867
2868 placeholders()->verify();
2869
2870 // Verify constraint table
2871 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2872 constraints()->verify(placeholders());
2873
2874 _pd_cache_table->verify();
2875 }
2876
2877 void SystemDictionary::dump(outputStream *st, bool verbose) {
2878 assert_locked_or_safepoint(SystemDictionary_lock);
2879 if (verbose) {
2880 print_on(st);
2881 } else {
2882 if (shared_dictionary() != NULL) {
2883 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2884 }
2885 ClassLoaderDataGraph::print_dictionary_statistics(st);
2886 placeholders()->print_table_statistics(st, "Placeholder Table");
2887 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2888 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2889 }
2890 }
2891
2892 // Utility for dumping dictionaries.
2893 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2894 DCmdWithParser(output, heap),
2895 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2896 "BOOLEAN", false, "false") {
2897 _dcmdparser.add_dcmd_option(&_verbose);
2898 }
2899
2900 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2901 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2902 _verbose.value());
2903 VMThread::execute(&dumper);
2904 }
2905
2906 int SystemDictionaryDCmd::num_arguments() {
2907 ResourceMark rm;
2908 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2909 if (dcmd != NULL) {
2910 DCmdMark mark(dcmd);
2911 return dcmd->_dcmdparser.num_arguments();
2912 } else {
2913 return 0;
2914 }
2915 }
2916
2917
2918 // caller needs ResourceMark
2919 const char* SystemDictionary::loader_name(const oop loader) {
2920 return ((loader) == NULL ? "<bootloader>" :
2921 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2922 }
2923
2924 // caller needs ResourceMark
2925 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2926 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2927 SystemDictionary::loader_name(loader_data->class_loader()));
2928 }