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/tracing.hpp"
81 #include "utilities/macros.hpp"
82 #if INCLUDE_CDS
83 #include "classfile/sharedClassUtil.hpp"
84 #include "classfile/systemDictionaryShared.hpp"
85 #endif
86 #if INCLUDE_JVMCI
87 #include "jvmci/jvmciRuntime.hpp"
88 #endif
89
90 PlaceholderTable* SystemDictionary::_placeholders = NULL;
91 Dictionary* SystemDictionary::_shared_dictionary = NULL;
92 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
93 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
94 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
95 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
96
97 int SystemDictionary::_number_of_modifications = 0;
98 oop SystemDictionary::_system_loader_lock_obj = NULL;
99
100 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
101 = { NULL /*, NULL...*/ };
102
103 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
104
105 oop SystemDictionary::_java_system_loader = NULL;
106
107 bool SystemDictionary::_has_loadClassInternal = false;
108 bool SystemDictionary::_has_checkPackageAccess = false;
109
110 // lazily initialized klass variables
111 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
112
113 // Default ProtectionDomainCacheSize value
114
115 const int defaultProtectionDomainCacheSize = 1009;
116
117
118 // ----------------------------------------------------------------------------
119 // Java-level SystemLoader
120
121 oop SystemDictionary::java_system_loader() {
122 return _java_system_loader;
123 }
124
125 void SystemDictionary::compute_java_system_loader(TRAPS) {
126 Klass* system_klass = WK_KLASS(ClassLoader_klass);
127 JavaValue result(T_OBJECT);
128 JavaCalls::call_static(&result,
129 WK_KLASS(ClassLoader_klass),
130 vmSymbols::getSystemClassLoader_name(),
131 vmSymbols::void_classloader_signature(),
132 CHECK);
133
134 _java_system_loader = (oop)result.get_jobject();
135
136 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
137 }
138
139
140 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
141 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
142 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
143 }
144
145 // ----------------------------------------------------------------------------
146 // Parallel class loading check
147
148 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
149 if (UnsyncloadClass || class_loader.is_null()) return true;
150 if (AlwaysLockClassLoader) return false;
151 return java_lang_ClassLoader::parallelCapable(class_loader());
152 }
153 // ----------------------------------------------------------------------------
154 // ParallelDefineClass flag does not apply to bootclass loader
155 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
156 if (class_loader.is_null()) return false;
157 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
158 return true;
159 }
160 return false;
161 }
162
163 // Returns true if the passed class loader is the builtin application class loader
164 // or a custom system class loader. A customer system class loader can be
165 // specified via -Djava.system.class.loader.
166 bool SystemDictionary::is_system_class_loader(oop class_loader) {
167 if (class_loader == NULL) {
168 return false;
169 }
170 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
171 class_loader == _java_system_loader);
172 }
173
174 // Returns true if the passed class loader is the platform class loader.
175 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
176 if (class_loader == NULL) {
177 return false;
178 }
179 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
180 }
181
182 // ----------------------------------------------------------------------------
183 // Resolving of classes
184
185 // Forwards to resolve_or_null
186
187 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
188 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
189 if (HAS_PENDING_EXCEPTION || klass == NULL) {
190 // can return a null klass
191 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
192 }
193 return klass;
194 }
195
196 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
197 bool throw_error,
198 Klass* klass, TRAPS) {
199 if (HAS_PENDING_EXCEPTION) {
200 // If we have a pending exception we forward it to the caller, unless throw_error is true,
201 // in which case we have to check whether the pending exception is a ClassNotFoundException,
202 // and if so convert it to a NoClassDefFoundError
203 // And chain the original ClassNotFoundException
204 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
205 ResourceMark rm(THREAD);
206 assert(klass == NULL, "Should not have result with exception pending");
207 Handle e(THREAD, PENDING_EXCEPTION);
208 CLEAR_PENDING_EXCEPTION;
209 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
210 } else {
211 return NULL;
212 }
213 }
214 // Class not found, throw appropriate error or exception depending on value of throw_error
215 if (klass == NULL) {
216 ResourceMark rm(THREAD);
217 if (throw_error) {
218 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
219 } else {
220 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
221 }
222 }
223 return klass;
224 }
225
226
227 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
228 bool throw_error, TRAPS)
229 {
230 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
231 }
232
233
234 // Forwards to resolve_instance_class_or_null
235
236 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
237 assert(THREAD->can_call_java(),
238 "can not load classes with compiler thread: class=%s, classloader=%s",
239 class_name->as_C_string(),
240 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
241 if (FieldType::is_array(class_name)) {
242 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
243 } else if (FieldType::is_obj(class_name)) {
244 ResourceMark rm(THREAD);
245 // Ignore wrapping L and ;.
246 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
247 class_name->utf8_length() - 2, CHECK_NULL);
248 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
249 } else {
250 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
251 }
252 }
253
254 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
255 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
256 }
257
258 // Forwards to resolve_instance_class_or_null
259
260 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
261 Handle class_loader,
262 Handle protection_domain,
263 TRAPS) {
264 assert(FieldType::is_array(class_name), "must be array");
265 Klass* k = NULL;
266 FieldArrayInfo fd;
267 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
268 // of this call
269 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
270 if (t == T_OBJECT) {
271 // naked oop "k" is OK here -- we assign back into it
272 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
273 class_loader,
274 protection_domain,
275 CHECK_NULL);
276 if (k != NULL) {
277 k = k->array_klass(fd.dimension(), CHECK_NULL);
278 }
279 } else {
280 k = Universe::typeArrayKlassObj(t);
281 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
282 }
283 return k;
284 }
285
286
287 // Must be called for any super-class or super-interface resolution
288 // during class definition to allow class circularity checking
289 // super-interface callers:
290 // parse_interfaces - for defineClass & jvmtiRedefineClasses
291 // super-class callers:
292 // ClassFileParser - for defineClass & jvmtiRedefineClasses
293 // load_shared_class - while loading a class from shared archive
294 // resolve_instance_class_or_null:
295 // via: handle_parallel_super_load
296 // when resolving a class that has an existing placeholder with
297 // a saved superclass [i.e. a defineClass is currently in progress]
298 // if another thread is trying to resolve the class, it must do
299 // super-class checks on its own thread to catch class circularity
300 // This last call is critical in class circularity checking for cases
301 // where classloading is delegated to different threads and the
302 // classloader lock is released.
303 // Take the case: Base->Super->Base
304 // 1. If thread T1 tries to do a defineClass of class Base
305 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
306 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
307 // so it tries to load Super
308 // 3. If we load the class internally, or user classloader uses same thread
309 // loadClassFromxxx or defineClass via parseClassFile Super ...
310 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
311 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
312 // 3.4 calls resolve_super_or_fail Base
313 // 3.5 finds T1,Base -> throws class circularity
314 //OR 4. If T2 tries to resolve Super via defineClass Super ...
315 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
316 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
317 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
318 // 4.4 finds T2, Super -> throws class circularity
319 // Must be called, even if superclass is null, since this is
320 // where the placeholder entry is created which claims this
321 // thread is loading this class/classloader.
322 // Be careful when modifying this code: once you have run
323 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
324 // you need to find_and_remove it before returning.
325 // So be careful to not exit with a CHECK_ macro betweeen these calls.
326 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
327 Symbol* class_name,
328 Handle class_loader,
329 Handle protection_domain,
330 bool is_superclass,
331 TRAPS) {
332 #if INCLUDE_CDS
333 if (DumpSharedSpaces) {
334 // Special processing for CDS dump time.
335 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
336 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
337 if (k) {
338 return k;
339 }
340 }
341 #endif // INCLUDE_CDS
342
343 // Double-check, if child class is already loaded, just return super-class,interface
344 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
345 // dictionary.
346 // Make sure there's a placeholder for the *child* before resolving.
347 // Used as a claim that this thread is currently loading superclass/classloader
348 // Used here for ClassCircularity checks and also for heap verification
349 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
350 // Must check ClassCircularity before checking if super class is already loaded.
351 //
352 // We might not already have a placeholder if this child_name was
353 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
354 // the name of the class might not be known until the stream is actually
355 // parsed.
356 // Bugs 4643874, 4715493
357
358 ClassLoaderData* loader_data = class_loader_data(class_loader);
359 Dictionary* dictionary = loader_data->dictionary();
360 unsigned int d_hash = dictionary->compute_hash(child_name);
361 int d_index = dictionary->hash_to_index(d_hash);
362 unsigned int p_hash = placeholders()->compute_hash(child_name);
363 int p_index = placeholders()->hash_to_index(p_hash);
364 // can't throw error holding a lock
365 bool child_already_loaded = false;
366 bool throw_circularity_error = false;
367 {
368 MutexLocker mu(SystemDictionary_lock, THREAD);
369 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
370 Klass* quicksuperk;
371 // to support // loading: if child done loading, just return superclass
372 // if class_name, & class_loader don't match:
373 // if initial define, SD update will give LinkageError
374 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
375 // so we don't throw an exception here.
376 // see: nsk redefclass014 & java.lang.instrument Instrument032
377 if ((childk != NULL ) && (is_superclass) &&
378 ((quicksuperk = childk->super()) != NULL) &&
379
380 ((quicksuperk->name() == class_name) &&
381 (quicksuperk->class_loader() == class_loader()))) {
382 return quicksuperk;
383 } else {
384 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
385 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
386 throw_circularity_error = true;
387 }
388 }
389 if (!throw_circularity_error) {
390 // Be careful not to exit resolve_super
391 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
392 }
393 }
394 if (throw_circularity_error) {
395 ResourceMark rm(THREAD);
396 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
397 }
398
399 // java.lang.Object should have been found above
400 assert(class_name != NULL, "null super class for resolving");
401 // Resolve the super class or interface, check results on return
402 Klass* superk = SystemDictionary::resolve_or_null(class_name,
403 class_loader,
404 protection_domain,
405 THREAD);
406
407 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
408 // It is no longer necessary to keep the placeholder table alive until update_dictionary
409 // or error. GC used to walk the placeholder table as strong roots.
410 // The instanceKlass is kept alive because the class loader is on the stack,
411 // which keeps the loader_data alive, as well as all instanceKlasses in
412 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
413 {
414 MutexLocker mu(SystemDictionary_lock, THREAD);
415 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
416 SystemDictionary_lock->notify_all();
417 }
418 if (HAS_PENDING_EXCEPTION || superk == NULL) {
419 // can null superk
420 superk = handle_resolution_exception(class_name, true, superk, THREAD);
421 }
422
423 return superk;
424 }
425
426 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
427 Handle class_loader,
428 Handle protection_domain,
429 TRAPS) {
430 if(!has_checkPackageAccess()) return;
431
432 // Now we have to call back to java to check if the initating class has access
433 JavaValue result(T_VOID);
434 LogTarget(Debug, protectiondomain) lt;
435 if (lt.is_enabled()) {
436 ResourceMark rm;
437 // Print out trace information
438 LogStream ls(lt);
439 ls.print_cr("Checking package access");
440 ls.print("class loader: "); class_loader()->print_value_on(&ls);
441 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
442 ls.print(" loading: "); klass->print_value_on(&ls);
443 ls.cr();
444 }
445
446 // This handle and the class_loader handle passed in keeps this class from
447 // being unloaded through several GC points.
448 // The class_loader handle passed in is the initiating loader.
449 Handle mirror(THREAD, klass->java_mirror());
450
451 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
452 JavaCalls::call_special(&result,
453 class_loader,
454 system_loader,
455 vmSymbols::checkPackageAccess_name(),
456 vmSymbols::class_protectiondomain_signature(),
457 mirror,
458 protection_domain,
459 THREAD);
460
461 if (HAS_PENDING_EXCEPTION) {
462 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
463 } else {
464 log_debug(protectiondomain)("granted");
465 }
466
467 if (HAS_PENDING_EXCEPTION) return;
468
469 // If no exception has been thrown, we have validated the protection domain
470 // Insert the protection domain of the initiating class into the set.
471 {
472 ClassLoaderData* loader_data = class_loader_data(class_loader);
473 Dictionary* dictionary = loader_data->dictionary();
474
475 Symbol* kn = klass->name();
476 unsigned int d_hash = dictionary->compute_hash(kn);
477 int d_index = dictionary->hash_to_index(d_hash);
478
479 MutexLocker mu(SystemDictionary_lock, THREAD);
480 dictionary->add_protection_domain(d_index, d_hash, klass,
481 protection_domain, THREAD);
482 }
483 }
484
485 // We only get here if this thread finds that another thread
486 // has already claimed the placeholder token for the current operation,
487 // but that other thread either never owned or gave up the
488 // object lock
489 // Waits on SystemDictionary_lock to indicate placeholder table updated
490 // On return, caller must recheck placeholder table state
491 //
492 // We only get here if
493 // 1) custom classLoader, i.e. not bootstrap classloader
494 // 2) UnsyncloadClass not set
495 // 3) custom classLoader has broken the class loader objectLock
496 // so another thread got here in parallel
497 //
498 // lockObject must be held.
499 // Complicated dance due to lock ordering:
500 // Must first release the classloader object lock to
501 // allow initial definer to complete the class definition
502 // and to avoid deadlock
503 // Reclaim classloader lock object with same original recursion count
504 // Must release SystemDictionary_lock after notify, since
505 // class loader lock must be claimed before SystemDictionary_lock
506 // to prevent deadlocks
507 //
508 // The notify allows applications that did an untimed wait() on
509 // the classloader object lock to not hang.
510 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
511 assert_lock_strong(SystemDictionary_lock);
512
513 bool calledholdinglock
514 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
515 assert(calledholdinglock,"must hold lock for notify");
516 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
517 ObjectSynchronizer::notifyall(lockObject, THREAD);
518 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
519 SystemDictionary_lock->wait();
520 SystemDictionary_lock->unlock();
521 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
522 SystemDictionary_lock->lock();
523 }
524
525 // If the class in is in the placeholder table, class loading is in progress
526 // For cases where the application changes threads to load classes, it
527 // is critical to ClassCircularity detection that we try loading
528 // the superclass on the same thread internally, so we do parallel
529 // super class loading here.
530 // This also is critical in cases where the original thread gets stalled
531 // even in non-circularity situations.
532 // Note: must call resolve_super_or_fail even if null super -
533 // to force placeholder entry creation for this class for circularity detection
534 // Caller must check for pending exception
535 // Returns non-null Klass* if other thread has completed load
536 // and we are done,
537 // If return null Klass* and no pending exception, the caller must load the class
538 InstanceKlass* SystemDictionary::handle_parallel_super_load(
539 Symbol* name, Symbol* superclassname, Handle class_loader,
540 Handle protection_domain, Handle lockObject, TRAPS) {
541
542 ClassLoaderData* loader_data = class_loader_data(class_loader);
543 Dictionary* dictionary = loader_data->dictionary();
544 unsigned int d_hash = dictionary->compute_hash(name);
545 int d_index = dictionary->hash_to_index(d_hash);
546 unsigned int p_hash = placeholders()->compute_hash(name);
547 int p_index = placeholders()->hash_to_index(p_hash);
548
549 // superk is not used, resolve_super called for circularity check only
550 // This code is reached in two situations. One if this thread
551 // is loading the same class twice (e.g. ClassCircularity, or
552 // java.lang.instrument).
553 // The second is if another thread started the resolve_super first
554 // and has not yet finished.
555 // In both cases the original caller will clean up the placeholder
556 // entry on error.
557 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
558 superclassname,
559 class_loader,
560 protection_domain,
561 true,
562 CHECK_NULL);
563
564 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
565 // Serial class loaders and bootstrap classloader do wait for superclass loads
566 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
567 MutexLocker mu(SystemDictionary_lock, THREAD);
568 // Check if classloading completed while we were loading superclass or waiting
569 return find_class(d_index, d_hash, name, dictionary);
570 }
571
572 // must loop to both handle other placeholder updates
573 // and spurious notifications
574 bool super_load_in_progress = true;
575 PlaceholderEntry* placeholder;
576 while (super_load_in_progress) {
577 MutexLocker mu(SystemDictionary_lock, THREAD);
578 // Check if classloading completed while we were loading superclass or waiting
579 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
580 if (check != NULL) {
581 // Klass is already loaded, so just return it
582 return check;
583 } else {
584 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
585 if (placeholder && placeholder->super_load_in_progress() ){
586 // Before UnsyncloadClass:
587 // We only get here if the application has released the
588 // classloader lock when another thread was in the middle of loading a
589 // superclass/superinterface for this class, and now
590 // this thread is also trying to load this class.
591 // To minimize surprises, the first thread that started to
592 // load a class should be the one to complete the loading
593 // with the classfile it initially expected.
594 // This logic has the current thread wait once it has done
595 // all the superclass/superinterface loading it can, until
596 // the original thread completes the class loading or fails
597 // If it completes we will use the resulting InstanceKlass
598 // which we will find below in the systemDictionary.
599 // We also get here for parallel bootstrap classloader
600 if (class_loader.is_null()) {
601 SystemDictionary_lock->wait();
602 } else {
603 double_lock_wait(lockObject, THREAD);
604 }
605 } else {
606 // If not in SD and not in PH, other thread's load must have failed
607 super_load_in_progress = false;
608 }
609 }
610 }
611 return NULL;
612 }
613
614 static void post_class_load_event(EventClassLoad* event,
615 const InstanceKlass* k,
616 const ClassLoaderData* init_cld) {
617 #if INCLUDE_TRACE
618 assert(event != NULL, "invariant");
619 assert(k != NULL, "invariant");
620 if (event->should_commit()) {
621 event->set_loadedClass(k);
622 event->set_definingClassLoader(k->class_loader_data());
623 event->set_initiatingClassLoader(init_cld);
624 event->commit();
625 }
626 #endif // INCLUDE_TRACE
627 }
628
629 static void class_define_event(InstanceKlass* k,
630 const ClassLoaderData* def_cld) {
631 #if INCLUDE_TRACE
632 EventClassDefine event;
633 if (event.should_commit()) {
634 event.set_definedClass(k);
635 event.set_definingClassLoader(def_cld);
636 event.commit();
637 }
638 #endif // INCLUDE_TRACE
639 }
640
641 // Be careful when modifying this code: once you have run
642 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
643 // you need to find_and_remove it before returning.
644 // So be careful to not exit with a CHECK_ macro betweeen these calls.
645 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
646 Handle class_loader,
647 Handle protection_domain,
648 TRAPS) {
649 assert(name != NULL && !FieldType::is_array(name) &&
650 !FieldType::is_obj(name), "invalid class name");
651
652 EventClassLoad class_load_start_event;
653
654 HandleMark hm(THREAD);
655
656 // Fix for 4474172; see evaluation for more details
657 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
658 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
659 Dictionary* dictionary = loader_data->dictionary();
660
661 // Do lookup to see if class already exist and the protection domain
662 // has the right access
663 // This call uses find which checks protection domain already matches
664 // All subsequent calls use find_class, and set has_loaded_class so that
665 // before we return a result we call out to java to check for valid protection domain
666 // to allow returning the Klass* and add it to the pd_set if it is valid
667 unsigned int d_hash = dictionary->compute_hash(name);
668 int d_index = dictionary->hash_to_index(d_hash);
669 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
670 if (probe != NULL) return probe;
671
672
673 // Non-bootstrap class loaders will call out to class loader and
674 // define via jvm/jni_DefineClass which will acquire the
675 // class loader object lock to protect against multiple threads
676 // defining the class in parallel by accident.
677 // This lock must be acquired here so the waiter will find
678 // any successful result in the SystemDictionary and not attempt
679 // the define
680 // ParallelCapable Classloaders and the bootstrap classloader,
681 // or all classloaders with UnsyncloadClass do not acquire lock here
682 bool DoObjectLock = true;
683 if (is_parallelCapable(class_loader)) {
684 DoObjectLock = false;
685 }
686
687 unsigned int p_hash = placeholders()->compute_hash(name);
688 int p_index = placeholders()->hash_to_index(p_hash);
689
690 // Class is not in SystemDictionary so we have to do loading.
691 // Make sure we are synchronized on the class loader before we proceed
692 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
693 check_loader_lock_contention(lockObject, THREAD);
694 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
695
696 // Check again (after locking) if class already exist in SystemDictionary
697 bool class_has_been_loaded = false;
698 bool super_load_in_progress = false;
699 bool havesupername = false;
700 InstanceKlass* k = NULL;
701 PlaceholderEntry* placeholder;
702 Symbol* superclassname = NULL;
703
704 {
705 MutexLocker mu(SystemDictionary_lock, THREAD);
706 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
707 if (check != NULL) {
708 // Klass is already loaded, so just return it
709 class_has_been_loaded = true;
710 k = check;
711 } else {
712 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
713 if (placeholder && placeholder->super_load_in_progress()) {
714 super_load_in_progress = true;
715 if (placeholder->havesupername() == true) {
716 superclassname = placeholder->supername();
717 havesupername = true;
718 }
719 }
720 }
721 }
722
723 // If the class is in the placeholder table, class loading is in progress
724 if (super_load_in_progress && havesupername==true) {
725 k = handle_parallel_super_load(name,
726 superclassname,
727 class_loader,
728 protection_domain,
729 lockObject, THREAD);
730 if (HAS_PENDING_EXCEPTION) {
731 return NULL;
732 }
733 if (k != NULL) {
734 class_has_been_loaded = true;
735 }
736 }
737
738 bool throw_circularity_error = false;
739 if (!class_has_been_loaded) {
740 bool load_instance_added = false;
741
742 // add placeholder entry to record loading instance class
743 // Five cases:
744 // All cases need to prevent modifying bootclasssearchpath
745 // in parallel with a classload of same classname
746 // Redefineclasses uses existence of the placeholder for the duration
747 // of the class load to prevent concurrent redefinition of not completely
748 // defined classes.
749 // case 1. traditional classloaders that rely on the classloader object lock
750 // - no other need for LOAD_INSTANCE
751 // case 2. traditional classloaders that break the classloader object lock
752 // as a deadlock workaround. Detection of this case requires that
753 // this check is done while holding the classloader object lock,
754 // and that lock is still held when calling classloader's loadClass.
755 // For these classloaders, we ensure that the first requestor
756 // completes the load and other requestors wait for completion.
757 // case 3. UnsyncloadClass - don't use objectLocker
758 // With this flag, we allow parallel classloading of a
759 // class/classloader pair
760 // case4. Bootstrap classloader - don't own objectLocker
761 // This classloader supports parallelism at the classloader level,
762 // but only allows a single load of a class/classloader pair.
763 // No performance benefit and no deadlock issues.
764 // case 5. parallelCapable user level classloaders - without objectLocker
765 // Allow parallel classloading of a class/classloader pair
766
767 {
768 MutexLocker mu(SystemDictionary_lock, THREAD);
769 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
770 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
771 if (oldprobe) {
772 // only need check_seen_thread once, not on each loop
773 // 6341374 java/lang/Instrument with -Xcomp
774 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
775 throw_circularity_error = true;
776 } else {
777 // case 1: traditional: should never see load_in_progress.
778 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
779
780 // case 4: bootstrap classloader: prevent futile classloading,
781 // wait on first requestor
782 if (class_loader.is_null()) {
783 SystemDictionary_lock->wait();
784 } else {
785 // case 2: traditional with broken classloader lock. wait on first
786 // requestor.
787 double_lock_wait(lockObject, THREAD);
788 }
789 // Check if classloading completed while we were waiting
790 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
791 if (check != NULL) {
792 // Klass is already loaded, so just return it
793 k = check;
794 class_has_been_loaded = true;
795 }
796 // check if other thread failed to load and cleaned up
797 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
798 }
799 }
800 }
801 }
802 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
803 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
804 // LOAD_INSTANCE in parallel
805
806 if (!throw_circularity_error && !class_has_been_loaded) {
807 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
808 load_instance_added = true;
809 // For class loaders that do not acquire the classloader object lock,
810 // if they did not catch another thread holding LOAD_INSTANCE,
811 // need a check analogous to the acquire ObjectLocker/find_class
812 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
813 // one final check if the load has already completed
814 // class loaders holding the ObjectLock shouldn't find the class here
815 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
816 if (check != NULL) {
817 // Klass is already loaded, so return it after checking/adding protection domain
818 k = check;
819 class_has_been_loaded = true;
820 }
821 }
822 }
823
824 // must throw error outside of owning lock
825 if (throw_circularity_error) {
826 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
827 ResourceMark rm(THREAD);
828 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
829 }
830
831 if (!class_has_been_loaded) {
832
833 // Do actual loading
834 k = load_instance_class(name, class_loader, THREAD);
835
836 // For UnsyncloadClass only
837 // If they got a linkageError, check if a parallel class load succeeded.
838 // If it did, then for bytecode resolution the specification requires
839 // that we return the same result we did for the other thread, i.e. the
840 // successfully loaded InstanceKlass
841 // Should not get here for classloaders that support parallelism
842 // with the new cleaner mechanism, even with AllowParallelDefineClass
843 // Bootstrap goes through here to allow for an extra guarantee check
844 if (UnsyncloadClass || (class_loader.is_null())) {
845 if (k == NULL && HAS_PENDING_EXCEPTION
846 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
847 MutexLocker mu(SystemDictionary_lock, THREAD);
848 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
849 if (check != NULL) {
850 // Klass is already loaded, so just use it
851 k = check;
852 CLEAR_PENDING_EXCEPTION;
853 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
854 }
855 }
856 }
857
858 // If everything was OK (no exceptions, no null return value), and
859 // class_loader is NOT the defining loader, do a little more bookkeeping.
860 if (!HAS_PENDING_EXCEPTION && k != NULL &&
861 k->class_loader() != class_loader()) {
862
863 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
864
865 // Need to check for a PENDING_EXCEPTION again; check_constraints
866 // can throw and doesn't use the CHECK macro.
867 if (!HAS_PENDING_EXCEPTION) {
868 { // Grabbing the Compile_lock prevents systemDictionary updates
869 // during compilations.
870 MutexLocker mu(Compile_lock, THREAD);
871 update_dictionary(d_index, d_hash, p_index, p_hash,
872 k, class_loader, THREAD);
873 }
874
875 if (JvmtiExport::should_post_class_load()) {
876 Thread *thread = THREAD;
877 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
878 JvmtiExport::post_class_load((JavaThread *) thread, k);
879 }
880 }
881 }
882 } // load_instance_class
883
884 if (load_instance_added == true) {
885 // clean up placeholder entries for LOAD_INSTANCE success or error
886 // This brackets the SystemDictionary updates for both defining
887 // and initiating loaders
888 MutexLocker mu(SystemDictionary_lock, THREAD);
889 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
890 SystemDictionary_lock->notify_all();
891 }
892 }
893
894 if (HAS_PENDING_EXCEPTION || k == NULL) {
895 return NULL;
896 }
897
898 post_class_load_event(&class_load_start_event, k, loader_data);
899
900 #ifdef ASSERT
901 {
902 ClassLoaderData* loader_data = k->class_loader_data();
903 MutexLocker mu(SystemDictionary_lock, THREAD);
904 Klass* kk = find_class(name, loader_data);
905 assert(kk == k, "should be present in dictionary");
906 }
907 #endif
908
909 // return if the protection domain in NULL
910 if (protection_domain() == NULL) return k;
911
912 // Check the protection domain has the right access
913 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
914 protection_domain)) {
915 return k;
916 }
917
918 // Verify protection domain. If it fails an exception is thrown
919 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
920
921 return k;
922 }
923
924
925 // This routine does not lock the system dictionary.
926 //
927 // Since readers don't hold a lock, we must make sure that system
928 // dictionary entries are only removed at a safepoint (when only one
929 // thread is running), and are added to in a safe way (all links must
930 // be updated in an MT-safe manner).
931 //
932 // Callers should be aware that an entry could be added just after
933 // _dictionary->bucket(index) is read here, so the caller will not see
934 // the new entry.
935
936 Klass* SystemDictionary::find(Symbol* class_name,
937 Handle class_loader,
938 Handle protection_domain,
939 TRAPS) {
940
941 // The result of this call should be consistent with the result
942 // of the call to resolve_instance_class_or_null().
943 // See evaluation 6790209 and 4474172 for more details.
944 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
945 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
946
947 if (loader_data == NULL) {
948 // If the ClassLoaderData has not been setup,
949 // then the class loader has no entries in the dictionary.
950 return NULL;
951 }
952
953 Dictionary* dictionary = loader_data->dictionary();
954 unsigned int d_hash = dictionary->compute_hash(class_name);
955 int d_index = dictionary->hash_to_index(d_hash);
956 return dictionary->find(d_index, d_hash, class_name,
957 protection_domain);
958 }
959
960
961 // Look for a loaded instance or array klass by name. Do not do any loading.
962 // return NULL in case of error.
963 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
964 Handle class_loader,
965 Handle protection_domain,
966 TRAPS) {
967 Klass* k = NULL;
968 assert(class_name != NULL, "class name must be non NULL");
969
970 if (FieldType::is_array(class_name)) {
971 // The name refers to an array. Parse the name.
972 // dimension and object_key in FieldArrayInfo are assigned as a
973 // side-effect of this call
974 FieldArrayInfo fd;
975 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
976 if (t != T_OBJECT) {
977 k = Universe::typeArrayKlassObj(t);
978 } else {
979 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
980 }
981 if (k != NULL) {
982 k = k->array_klass_or_null(fd.dimension());
983 }
984 } else {
985 k = find(class_name, class_loader, protection_domain, THREAD);
986 }
987 return k;
988 }
989
990 // Note: this method is much like resolve_from_stream, but
991 // does not publish the classes via the SystemDictionary.
992 // Handles unsafe_DefineAnonymousClass and redefineclasses
993 // RedefinedClasses do not add to the class hierarchy
994 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
995 Handle class_loader,
996 Handle protection_domain,
997 ClassFileStream* st,
998 const InstanceKlass* host_klass,
999 GrowableArray<Handle>* cp_patches,
1000 TRAPS) {
1001
1002 EventClassLoad class_load_start_event;
1003
1004 ClassLoaderData* loader_data;
1005 if (host_klass != NULL) {
1006 // Create a new CLD for anonymous class, that uses the same class loader
1007 // as the host_klass
1008 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1009 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1010 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1011 } else {
1012 loader_data = ClassLoaderData::class_loader_data(class_loader());
1013 }
1014
1015 assert(st != NULL, "invariant");
1016 assert(st->need_verify(), "invariant");
1017
1018 // Parse stream and create a klass.
1019 // Note that we do this even though this klass might
1020 // already be present in the SystemDictionary, otherwise we would not
1021 // throw potential ClassFormatErrors.
1022
1023 InstanceKlass* k = KlassFactory::create_from_stream(st,
1024 class_name,
1025 loader_data,
1026 protection_domain,
1027 host_klass,
1028 cp_patches,
1029 CHECK_NULL);
1030
1031 if (host_klass != NULL && k != NULL) {
1032 // If it's anonymous, initialize it now, since nobody else will.
1033
1034 {
1035 MutexLocker mu_r(Compile_lock, THREAD);
1036
1037 // Add to class hierarchy, initialize vtables, and do possible
1038 // deoptimizations.
1039 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1040
1041 // But, do not add to dictionary.
1042
1043 // compiled code dependencies need to be validated anyway
1044 notice_modification();
1045 }
1046
1047 // Rewrite and patch constant pool here.
1048 k->link_class(CHECK_NULL);
1049 if (cp_patches != NULL) {
1050 k->constants()->patch_resolved_references(cp_patches);
1051 }
1052 k->eager_initialize(CHECK_NULL);
1053
1054 // notify jvmti
1055 if (JvmtiExport::should_post_class_load()) {
1056 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1057 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1058 }
1059
1060 post_class_load_event(&class_load_start_event, k, loader_data);
1061 }
1062 assert(host_klass != NULL || NULL == cp_patches,
1063 "cp_patches only found with host_klass");
1064
1065 return k;
1066 }
1067
1068 // Add a klass to the system from a stream (called by jni_DefineClass and
1069 // JVM_DefineClass).
1070 // Note: class_name can be NULL. In that case we do not know the name of
1071 // the class until we have parsed the stream.
1072
1073 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1074 Handle class_loader,
1075 Handle protection_domain,
1076 ClassFileStream* st,
1077 TRAPS) {
1078
1079 HandleMark hm(THREAD);
1080
1081 // Classloaders that support parallelism, e.g. bootstrap classloader,
1082 // or all classloaders with UnsyncloadClass do not acquire lock here
1083 bool DoObjectLock = true;
1084 if (is_parallelCapable(class_loader)) {
1085 DoObjectLock = false;
1086 }
1087
1088 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1089
1090 // Make sure we are synchronized on the class loader before we proceed
1091 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1092 check_loader_lock_contention(lockObject, THREAD);
1093 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1094
1095 assert(st != NULL, "invariant");
1096
1097 // Parse the stream and create a klass.
1098 // Note that we do this even though this klass might
1099 // already be present in the SystemDictionary, otherwise we would not
1100 // throw potential ClassFormatErrors.
1101 InstanceKlass* k = NULL;
1102
1103 #if INCLUDE_CDS
1104 k = SystemDictionaryShared::lookup_from_stream(class_name,
1105 class_loader,
1106 protection_domain,
1107 st,
1108 CHECK_NULL);
1109 #endif
1110
1111 if (k == NULL) {
1112 if (st->buffer() == NULL) {
1113 return NULL;
1114 }
1115 k = KlassFactory::create_from_stream(st,
1116 class_name,
1117 loader_data,
1118 protection_domain,
1119 NULL, // host_klass
1120 NULL, // cp_patches
1121 CHECK_NULL);
1122 }
1123
1124 assert(k != NULL, "no klass created");
1125 Symbol* h_name = k->name();
1126 assert(class_name == NULL || class_name == h_name, "name mismatch");
1127
1128 // Add class just loaded
1129 // If a class loader supports parallel classloading handle parallel define requests
1130 // find_or_define_instance_class may return a different InstanceKlass
1131 if (is_parallelCapable(class_loader)) {
1132 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1133 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1134 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1135 assert(defined_k != NULL, "Should have a klass if there's no exception");
1136 loader_data->add_to_deallocate_list(k);
1137 k = defined_k;
1138 }
1139 } else {
1140 define_instance_class(k, THREAD);
1141 }
1142
1143 // If defining the class throws an exception register 'k' for cleanup.
1144 if (HAS_PENDING_EXCEPTION) {
1145 assert(k != NULL, "Must have an instance klass here!");
1146 loader_data->add_to_deallocate_list(k);
1147 return NULL;
1148 }
1149
1150 // Make sure we have an entry in the SystemDictionary on success
1151 debug_only( {
1152 MutexLocker mu(SystemDictionary_lock, THREAD);
1153
1154 Klass* check = find_class(h_name, k->class_loader_data());
1155 assert(check == k, "should be present in the dictionary");
1156 } );
1157
1158 return k;
1159 }
1160
1161 #if INCLUDE_CDS
1162 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1163 int number_of_entries) {
1164 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1165 "bad shared dictionary size.");
1166 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1167 _shared_dictionary_size, t, number_of_entries);
1168 }
1169
1170
1171 // If there is a shared dictionary, then find the entry for the
1172 // given shared system class, if any.
1173
1174 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1175 if (shared_dictionary() != NULL) {
1176 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1177 int d_index = shared_dictionary()->hash_to_index(d_hash);
1178
1179 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1180 } else {
1181 return NULL;
1182 }
1183 }
1184
1185
1186 // Load a class from the shared spaces (found through the shared system
1187 // dictionary). Force the superclass and all interfaces to be loaded.
1188 // Update the class definition to include sibling classes and no
1189 // subclasses (yet). [Classes in the shared space are not part of the
1190 // object hierarchy until loaded.]
1191
1192 InstanceKlass* SystemDictionary::load_shared_class(
1193 Symbol* class_name, Handle class_loader, TRAPS) {
1194 InstanceKlass* ik = find_shared_class(class_name);
1195 // Make sure we only return the boot class for the NULL classloader.
1196 if (ik != NULL &&
1197 ik->is_shared_boot_class() && class_loader.is_null()) {
1198 Handle protection_domain;
1199 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1200 }
1201 return NULL;
1202 }
1203
1204 // Check if a shared class can be loaded by the specific classloader:
1205 //
1206 // NULL classloader:
1207 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1208 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1209 // be defined in an unnamed module.
1210 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1211 InstanceKlass* ik,
1212 Handle class_loader, TRAPS) {
1213 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1214 "Cannot use sharing if java.base is patched");
1215 ResourceMark rm;
1216 int path_index = ik->shared_classpath_index();
1217 SharedClassPathEntry* ent =
1218 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1219 if (!Universe::is_module_initialized()) {
1220 assert(ent != NULL && ent->is_jrt(),
1221 "Loading non-bootstrap classes before the module system is initialized");
1222 assert(class_loader.is_null(), "sanity");
1223 return true;
1224 }
1225 // Get the pkg_entry from the classloader
1226 TempNewSymbol pkg_name = NULL;
1227 PackageEntry* pkg_entry = NULL;
1228 ModuleEntry* mod_entry = NULL;
1229 const char* pkg_string = NULL;
1230 ClassLoaderData* loader_data = class_loader_data(class_loader);
1231 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1232 if (pkg_name != NULL) {
1233 pkg_string = pkg_name->as_C_string();
1234 if (loader_data != NULL) {
1235 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1236 }
1237 if (pkg_entry != NULL) {
1238 mod_entry = pkg_entry->module();
1239 }
1240 }
1241
1242 // If the archived class is from a module that has been patched at runtime,
1243 // the class cannot be loaded from the archive.
1244 if (mod_entry != NULL && mod_entry->is_patched()) {
1245 return false;
1246 }
1247
1248 if (class_loader.is_null()) {
1249 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1250 // The NULL classloader can load archived class originated from the
1251 // "modules" jimage and the -Xbootclasspath/a. For class from the
1252 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1253 // by the NULL classloader.
1254 if (mod_entry != NULL) {
1255 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1256 // ModuleEntry's location agrees with the archived class' origination.
1257 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1258 return true; // Module class from the "module" jimage
1259 }
1260 }
1261
1262 // If the archived class is not from the "module" jimage, the class can be
1263 // loaded by the NULL classloader if
1264 //
1265 // 1. the class is from the unamed package
1266 // 2. or, the class is not from a module defined in the NULL classloader
1267 // 3. or, the class is from an unamed module
1268 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1269 // the class is from the -Xbootclasspath/a
1270 if (pkg_string == NULL ||
1271 pkg_entry == NULL ||
1272 pkg_entry->in_unnamed_module()) {
1273 assert(mod_entry == NULL ||
1274 mod_entry == loader_data->unnamed_module(),
1275 "the unnamed module is not defined in the classloader");
1276 return true;
1277 }
1278 }
1279 return false;
1280 } else {
1281 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1282 ik, class_loader, pkg_string, pkg_name,
1283 pkg_entry, mod_entry, CHECK_(false));
1284 return res;
1285 }
1286 }
1287
1288 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1289 Handle class_loader,
1290 Handle protection_domain, TRAPS) {
1291
1292 if (ik != NULL) {
1293 Symbol* class_name = ik->name();
1294
1295 bool visible = is_shared_class_visible(
1296 class_name, ik, class_loader, CHECK_NULL);
1297 if (!visible) {
1298 return NULL;
1299 }
1300
1301 // Resolve the superclass and interfaces. They must be the same
1302 // as in dump time, because the layout of <ik> depends on
1303 // the specific layout of ik->super() and ik->local_interfaces().
1304 //
1305 // If unexpected superclass or interfaces are found, we cannot
1306 // load <ik> from the shared archive.
1307
1308 if (ik->super() != NULL) {
1309 Symbol* cn = ik->super()->name();
1310 Klass *s = resolve_super_or_fail(class_name, cn,
1311 class_loader, protection_domain, true, CHECK_NULL);
1312 if (s != ik->super()) {
1313 // The dynamically resolved super class is not the same as the one we used during dump time,
1314 // so we cannot use ik.
1315 return NULL;
1316 } else {
1317 assert(s->is_shared(), "must be");
1318 }
1319 }
1320
1321 Array<Klass*>* interfaces = ik->local_interfaces();
1322 int num_interfaces = interfaces->length();
1323 for (int index = 0; index < num_interfaces; index++) {
1324 Klass* k = interfaces->at(index);
1325 Symbol* name = k->name();
1326 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1327 if (k != i) {
1328 // The dynamically resolved interface class is not the same as the one we used during dump time,
1329 // so we cannot use ik.
1330 return NULL;
1331 } else {
1332 assert(i->is_shared(), "must be");
1333 }
1334 }
1335
1336 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1337 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1338 if (new_ik != NULL) {
1339 // The class is changed by CFLH. Return the new class. The shared class is
1340 // not used.
1341 return new_ik;
1342 }
1343
1344 // Adjust methods to recover missing data. They need addresses for
1345 // interpreter entry points and their default native method address
1346 // must be reset.
1347
1348 // Updating methods must be done under a lock so multiple
1349 // threads don't update these in parallel
1350 //
1351 // Shared classes are all currently loaded by either the bootstrap or
1352 // internal parallel class loaders, so this will never cause a deadlock
1353 // on a custom class loader lock.
1354
1355 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1356 {
1357 HandleMark hm(THREAD);
1358 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1359 check_loader_lock_contention(lockObject, THREAD);
1360 ObjectLocker ol(lockObject, THREAD, true);
1361 // prohibited package check assumes all classes loaded from archive call
1362 // restore_unshareable_info which calls ik->set_package()
1363 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1364 }
1365
1366 ik->print_class_load_logging(loader_data, NULL, NULL);
1367
1368 // For boot loader, ensure that GetSystemPackage knows that a class in this
1369 // package was loaded.
1370 if (class_loader.is_null()) {
1371 int path_index = ik->shared_classpath_index();
1372 ResourceMark rm;
1373 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1374 }
1375
1376 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1377 // Only dump the classes that can be stored into CDS archive
1378 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1379 ResourceMark rm(THREAD);
1380 classlist_file->print_cr("%s", ik->name()->as_C_string());
1381 classlist_file->flush();
1382 }
1383 }
1384
1385 // notify a class loaded from shared object
1386 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1387 }
1388
1389 ik->set_has_passed_fingerprint_check(false);
1390 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1391 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1392 uint64_t cds_fp = ik->get_stored_fingerprint();
1393 if (aot_fp != 0 && aot_fp == cds_fp) {
1394 // This class matches with a class saved in an AOT library
1395 ik->set_has_passed_fingerprint_check(true);
1396 } else {
1397 ResourceMark rm;
1398 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1399 }
1400 }
1401 return ik;
1402 }
1403 #endif // INCLUDE_CDS
1404
1405 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1406
1407 if (class_loader.is_null()) {
1408 ResourceMark rm;
1409 PackageEntry* pkg_entry = NULL;
1410 bool search_only_bootloader_append = false;
1411 ClassLoaderData *loader_data = class_loader_data(class_loader);
1412
1413 // Find the package in the boot loader's package entry table.
1414 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1415 if (pkg_name != NULL) {
1416 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1417 }
1418
1419 // Prior to attempting to load the class, enforce the boot loader's
1420 // visibility boundaries.
1421 if (!Universe::is_module_initialized()) {
1422 // During bootstrapping, prior to module initialization, any
1423 // class attempting to be loaded must be checked against the
1424 // java.base packages in the boot loader's PackageEntryTable.
1425 // No class outside of java.base is allowed to be loaded during
1426 // this bootstrapping window.
1427 if (!DumpSharedSpaces) {
1428 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1429 // Class is either in the unnamed package or in
1430 // a named package within the unnamed module. Either
1431 // case is outside of java.base, do not attempt to
1432 // load the class post java.base definition. If
1433 // java.base has not been defined, let the class load
1434 // and its package will be checked later by
1435 // ModuleEntryTable::verify_javabase_packages.
1436 if (ModuleEntryTable::javabase_defined()) {
1437 return NULL;
1438 }
1439 } else {
1440 // Check that the class' package is defined within java.base.
1441 ModuleEntry* mod_entry = pkg_entry->module();
1442 Symbol* mod_entry_name = mod_entry->name();
1443 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1444 return NULL;
1445 }
1446 }
1447 }
1448 } else {
1449 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1450 // After the module system has been initialized, check if the class'
1451 // package is in a module defined to the boot loader.
1452 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1453 // Class is either in the unnamed package, in a named package
1454 // within a module not defined to the boot loader or in a
1455 // a named package within the unnamed module. In all cases,
1456 // limit visibility to search for the class only in the boot
1457 // loader's append path.
1458 search_only_bootloader_append = true;
1459 }
1460 }
1461
1462 // Prior to bootstrapping's module initialization, never load a class outside
1463 // of the boot loader's module path
1464 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1465 !search_only_bootloader_append,
1466 "Attempt to load a class outside of boot loader's module path");
1467
1468 // Search the shared system dictionary for classes preloaded into the
1469 // shared spaces.
1470 InstanceKlass* k = NULL;
1471 {
1472 #if INCLUDE_CDS
1473 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1474 k = load_shared_class(class_name, class_loader, THREAD);
1475 #endif
1476 }
1477
1478 if (k == NULL) {
1479 // Use VM class loader
1480 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1481 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1482 }
1483
1484 // find_or_define_instance_class may return a different InstanceKlass
1485 if (k != NULL) {
1486 InstanceKlass* defined_k =
1487 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1488 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1489 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1490 assert(defined_k != NULL, "Should have a klass if there's no exception");
1491 loader_data->add_to_deallocate_list(k);
1492 k = defined_k;
1493 } else if (HAS_PENDING_EXCEPTION) {
1494 loader_data->add_to_deallocate_list(k);
1495 return NULL;
1496 }
1497 }
1498 return k;
1499 } else {
1500 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1501 ResourceMark rm(THREAD);
1502
1503 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1504 JavaThread* jt = (JavaThread*) THREAD;
1505
1506 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1507 ClassLoader::perf_app_classload_selftime(),
1508 ClassLoader::perf_app_classload_count(),
1509 jt->get_thread_stat()->perf_recursion_counts_addr(),
1510 jt->get_thread_stat()->perf_timers_addr(),
1511 PerfClassTraceTime::CLASS_LOAD);
1512
1513 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1514 // Translate to external class name format, i.e., convert '/' chars to '.'
1515 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1516
1517 JavaValue result(T_OBJECT);
1518
1519 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1520
1521 // Call public unsynchronized loadClass(String) directly for all class loaders
1522 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1523 // acquire a class-name based lock rather than the class loader object lock.
1524 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1525 // so the call to loadClassInternal() was not required.
1526 //
1527 // UnsyncloadClass flag means both call loadClass(String) and do
1528 // not acquire the class loader lock even for class loaders that are
1529 // not parallelCapable. This was a risky transitional
1530 // flag for diagnostic purposes only. It is risky to call
1531 // custom class loaders without synchronization.
1532 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1533 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1534 // Do NOT assume this will be supported in future releases.
1535 //
1536 // Added MustCallLoadClassInternal in case we discover in the field
1537 // a customer that counts on this call
1538 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1539 JavaCalls::call_special(&result,
1540 class_loader,
1541 spec_klass,
1542 vmSymbols::loadClassInternal_name(),
1543 vmSymbols::string_class_signature(),
1544 string,
1545 CHECK_NULL);
1546 } else {
1547 JavaCalls::call_virtual(&result,
1548 class_loader,
1549 spec_klass,
1550 vmSymbols::loadClass_name(),
1551 vmSymbols::string_class_signature(),
1552 string,
1553 CHECK_NULL);
1554 }
1555
1556 assert(result.get_type() == T_OBJECT, "just checking");
1557 oop obj = (oop) result.get_jobject();
1558
1559 // Primitive classes return null since forName() can not be
1560 // used to obtain any of the Class objects representing primitives or void
1561 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1562 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1563 // For user defined Java class loaders, check that the name returned is
1564 // the same as that requested. This check is done for the bootstrap
1565 // loader when parsing the class file.
1566 if (class_name == k->name()) {
1567 return k;
1568 }
1569 }
1570 // Class is not found or has the wrong name, return NULL
1571 return NULL;
1572 }
1573 }
1574
1575 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1576
1577 HandleMark hm(THREAD);
1578 ClassLoaderData* loader_data = k->class_loader_data();
1579 Handle class_loader_h(THREAD, loader_data->class_loader());
1580
1581 // for bootstrap and other parallel classloaders don't acquire lock,
1582 // use placeholder token
1583 // If a parallelCapable class loader calls define_instance_class instead of
1584 // find_or_define_instance_class to get here, we have a timing
1585 // hole with systemDictionary updates and check_constraints
1586 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1587 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1588 compute_loader_lock_object(class_loader_h, THREAD)),
1589 "define called without lock");
1590 }
1591
1592 // Check class-loading constraints. Throw exception if violation is detected.
1593 // Grabs and releases SystemDictionary_lock
1594 // The check_constraints/find_class call and update_dictionary sequence
1595 // must be "atomic" for a specific class/classloader pair so we never
1596 // define two different instanceKlasses for that class/classloader pair.
1597 // Existing classloaders will call define_instance_class with the
1598 // classloader lock held
1599 // Parallel classloaders will call find_or_define_instance_class
1600 // which will require a token to perform the define class
1601 Symbol* name_h = k->name();
1602 Dictionary* dictionary = loader_data->dictionary();
1603 unsigned int d_hash = dictionary->compute_hash(name_h);
1604 int d_index = dictionary->hash_to_index(d_hash);
1605 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1606
1607 // Register class just loaded with class loader (placed in Vector)
1608 // Note we do this before updating the dictionary, as this can
1609 // fail with an OutOfMemoryError (if it does, we will *not* put this
1610 // class in the dictionary and will not update the class hierarchy).
1611 // JVMTI FollowReferences needs to find the classes this way.
1612 if (k->class_loader() != NULL) {
1613 methodHandle m(THREAD, Universe::loader_addClass_method());
1614 JavaValue result(T_VOID);
1615 JavaCallArguments args(class_loader_h);
1616 args.push_oop(Handle(THREAD, k->java_mirror()));
1617 JavaCalls::call(&result, m, &args, CHECK);
1618 }
1619
1620 // Add the new class. We need recompile lock during update of CHA.
1621 {
1622 unsigned int p_hash = placeholders()->compute_hash(name_h);
1623 int p_index = placeholders()->hash_to_index(p_hash);
1624
1625 MutexLocker mu_r(Compile_lock, THREAD);
1626
1627 // Add to class hierarchy, initialize vtables, and do possible
1628 // deoptimizations.
1629 add_to_hierarchy(k, CHECK); // No exception, but can block
1630
1631 // Add to systemDictionary - so other classes can see it.
1632 // Grabs and releases SystemDictionary_lock
1633 update_dictionary(d_index, d_hash, p_index, p_hash,
1634 k, class_loader_h, THREAD);
1635 }
1636 k->eager_initialize(THREAD);
1637
1638 // notify jvmti
1639 if (JvmtiExport::should_post_class_load()) {
1640 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1641 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1642
1643 }
1644 class_define_event(k, loader_data);
1645 }
1646
1647 // Support parallel classloading
1648 // All parallel class loaders, including bootstrap classloader
1649 // lock a placeholder entry for this class/class_loader pair
1650 // to allow parallel defines of different classes for this class loader
1651 // With AllowParallelDefine flag==true, in case they do not synchronize around
1652 // FindLoadedClass/DefineClass, calls, we check for parallel
1653 // loading for them, wait if a defineClass is in progress
1654 // and return the initial requestor's results
1655 // This flag does not apply to the bootstrap classloader.
1656 // With AllowParallelDefine flag==false, call through to define_instance_class
1657 // which will throw LinkageError: duplicate class definition.
1658 // False is the requested default.
1659 // For better performance, the class loaders should synchronize
1660 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1661 // potentially waste time reading and parsing the bytestream.
1662 // Note: VM callers should ensure consistency of k/class_name,class_loader
1663 // Be careful when modifying this code: once you have run
1664 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1665 // you need to find_and_remove it before returning.
1666 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1667 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1668 InstanceKlass* k, TRAPS) {
1669
1670 Symbol* name_h = k->name(); // passed in class_name may be null
1671 ClassLoaderData* loader_data = class_loader_data(class_loader);
1672 Dictionary* dictionary = loader_data->dictionary();
1673
1674 unsigned int d_hash = dictionary->compute_hash(name_h);
1675 int d_index = dictionary->hash_to_index(d_hash);
1676
1677 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1678 unsigned int p_hash = placeholders()->compute_hash(name_h);
1679 int p_index = placeholders()->hash_to_index(p_hash);
1680 PlaceholderEntry* probe;
1681
1682 {
1683 MutexLocker mu(SystemDictionary_lock, THREAD);
1684 // First check if class already defined
1685 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1686 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1687 if (check != NULL) {
1688 return check;
1689 }
1690 }
1691
1692 // Acquire define token for this class/classloader
1693 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1694 // Wait if another thread defining in parallel
1695 // All threads wait - even those that will throw duplicate class: otherwise
1696 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1697 // if other thread has not finished updating dictionary
1698 while (probe->definer() != NULL) {
1699 SystemDictionary_lock->wait();
1700 }
1701 // Only special cases allow parallel defines and can use other thread's results
1702 // Other cases fall through, and may run into duplicate defines
1703 // caught by finding an entry in the SystemDictionary
1704 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1705 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1706 SystemDictionary_lock->notify_all();
1707 #ifdef ASSERT
1708 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1709 assert(check != NULL, "definer missed recording success");
1710 #endif
1711 return probe->instance_klass();
1712 } else {
1713 // This thread will define the class (even if earlier thread tried and had an error)
1714 probe->set_definer(THREAD);
1715 }
1716 }
1717
1718 define_instance_class(k, THREAD);
1719
1720 Handle linkage_exception = Handle(); // null handle
1721
1722 // definer must notify any waiting threads
1723 {
1724 MutexLocker mu(SystemDictionary_lock, THREAD);
1725 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1726 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1727 if (probe != NULL) {
1728 if (HAS_PENDING_EXCEPTION) {
1729 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1730 CLEAR_PENDING_EXCEPTION;
1731 } else {
1732 probe->set_instance_klass(k);
1733 }
1734 probe->set_definer(NULL);
1735 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1736 SystemDictionary_lock->notify_all();
1737 }
1738 }
1739
1740 // Can't throw exception while holding lock due to rank ordering
1741 if (linkage_exception() != NULL) {
1742 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1743 }
1744
1745 return k;
1746 }
1747
1748 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1749 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1750 if (class_loader.is_null()) {
1751 return Handle(THREAD, _system_loader_lock_obj);
1752 } else {
1753 return class_loader;
1754 }
1755 }
1756
1757 // This method is added to check how often we have to wait to grab loader
1758 // lock. The results are being recorded in the performance counters defined in
1759 // ClassLoader::_sync_systemLoaderLockContentionRate and
1760 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1761 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1762 if (!UsePerfData) {
1763 return;
1764 }
1765
1766 assert(!loader_lock.is_null(), "NULL lock object");
1767
1768 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1769 == ObjectSynchronizer::owner_other) {
1770 // contention will likely happen, so increment the corresponding
1771 // contention counter.
1772 if (loader_lock() == _system_loader_lock_obj) {
1773 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1774 } else {
1775 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1776 }
1777 }
1778 }
1779
1780 // ----------------------------------------------------------------------------
1781 // Lookup
1782
1783 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1784 Symbol* class_name,
1785 Dictionary* dictionary) {
1786 assert_locked_or_safepoint(SystemDictionary_lock);
1787 return dictionary->find_class(index, hash, class_name);
1788 }
1789
1790
1791 // Basic find on classes in the midst of being loaded
1792 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1793 ClassLoaderData* loader_data) {
1794 assert_locked_or_safepoint(SystemDictionary_lock);
1795 unsigned int p_hash = placeholders()->compute_hash(class_name);
1796 int p_index = placeholders()->hash_to_index(p_hash);
1797 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1798 }
1799
1800
1801 // Used for assertions and verification only
1802 // Precalculating the hash and index is an optimization because there are many lookups
1803 // before adding the class.
1804 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1805 assert_locked_or_safepoint(SystemDictionary_lock);
1806 #ifndef ASSERT
1807 guarantee(VerifyBeforeGC ||
1808 VerifyDuringGC ||
1809 VerifyBeforeExit ||
1810 VerifyDuringStartup ||
1811 VerifyAfterGC, "too expensive");
1812 #endif
1813
1814 Dictionary* dictionary = loader_data->dictionary();
1815 unsigned int d_hash = dictionary->compute_hash(class_name);
1816 int d_index = dictionary->hash_to_index(d_hash);
1817 return find_class(d_index, d_hash, class_name, dictionary);
1818 }
1819
1820
1821 // ----------------------------------------------------------------------------
1822 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1823 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1824 // before a new class is used.
1825
1826 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1827 assert(k != NULL, "just checking");
1828 assert_locked_or_safepoint(Compile_lock);
1829
1830 // Link into hierachy. Make sure the vtables are initialized before linking into
1831 k->append_to_sibling_list(); // add to superklass/sibling list
1832 k->process_interfaces(THREAD); // handle all "implements" declarations
1833 k->set_init_state(InstanceKlass::loaded);
1834 // Now flush all code that depended on old class hierarchy.
1835 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1836 // Also, first reinitialize vtable because it may have gotten out of synch
1837 // while the new class wasn't connected to the class hierarchy.
1838 CodeCache::flush_dependents_on(k);
1839 }
1840
1841 // ----------------------------------------------------------------------------
1842 // GC support
1843
1844 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1845 roots_oops_do(blk, NULL);
1846 }
1847
1848
1849 #ifdef ASSERT
1850 class VerifySDReachableAndLiveClosure : public OopClosure {
1851 private:
1852 BoolObjectClosure* _is_alive;
1853
1854 template <class T> void do_oop_work(T* p) {
1855 oop obj = oopDesc::load_decode_heap_oop(p);
1856 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1857 }
1858
1859 public:
1860 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1861
1862 virtual void do_oop(oop* p) { do_oop_work(p); }
1863 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1864 };
1865 #endif
1866
1867 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1868 // Note: anonymous classes are not in the SD.
1869 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1870 GCTimer* gc_timer,
1871 bool do_cleaning) {
1872
1873
1874 bool unloading_occurred;
1875 {
1876 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1877
1878 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1879 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1880 do_cleaning);
1881 }
1882
1883 if (unloading_occurred) {
1884 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1885 constraints()->purge_loader_constraints();
1886 resolution_errors()->purge_resolution_errors();
1887 }
1888
1889 {
1890 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1891 // Oops referenced by the protection domain cache table may get unreachable independently
1892 // of the class loader (eg. cached protection domain oops). So we need to
1893 // explicitly unlink them here.
1894 _pd_cache_table->unlink(is_alive);
1895
1896 #ifdef ASSERT
1897 VerifySDReachableAndLiveClosure cl(is_alive);
1898 _pd_cache_table->oops_do(&cl);
1899 #endif
1900 }
1901
1902 if (do_cleaning) {
1903 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1904 ResolvedMethodTable::unlink(is_alive);
1905 }
1906
1907 return unloading_occurred;
1908 }
1909
1910 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1911 strong->do_oop(&_java_system_loader);
1912 strong->do_oop(&_system_loader_lock_obj);
1913 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1914
1915 // Do strong roots marking if the closures are the same.
1916 if (strong == weak || !ClassUnloading) {
1917 // Only the protection domain oops contain references into the heap. Iterate
1918 // over all of them.
1919 _pd_cache_table->oops_do(strong);
1920 } else {
1921 if (weak != NULL) {
1922 _pd_cache_table->oops_do(weak);
1923 }
1924 }
1925
1926 // Visit extra methods
1927 invoke_method_table()->oops_do(strong);
1928
1929 if (weak != NULL) {
1930 ResolvedMethodTable::oops_do(weak);
1931 }
1932 }
1933
1934 void SystemDictionary::oops_do(OopClosure* f) {
1935 f->do_oop(&_java_system_loader);
1936 f->do_oop(&_system_loader_lock_obj);
1937 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1938
1939 // Only the protection domain oops contain references into the heap. Iterate
1940 // over all of them.
1941 _pd_cache_table->oops_do(f);
1942
1943 // Visit extra methods
1944 invoke_method_table()->oops_do(f);
1945
1946 ResolvedMethodTable::oops_do(f);
1947 }
1948
1949 // CDS: scan and relocate all classes in the system dictionary.
1950 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1951 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1952 }
1953
1954 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1955 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1956 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1957 it->push(well_known_klass_addr((WKID)id));
1958 }
1959 }
1960
1961 void SystemDictionary::methods_do(void f(Method*)) {
1962 // Walk methods in loaded classes
1963 ClassLoaderDataGraph::methods_do(f);
1964 // Walk method handle intrinsics
1965 invoke_method_table()->methods_do(f);
1966 }
1967
1968 void SystemDictionary::remove_classes_in_error_state() {
1969 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1970 }
1971
1972 // ----------------------------------------------------------------------------
1973 // Lazily load klasses
1974
1975 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1976 // if multiple threads calling this function, only one thread will load
1977 // the class. The other threads will find the loaded version once the
1978 // class is loaded.
1979 Klass* aos = _abstract_ownable_synchronizer_klass;
1980 if (aos == NULL) {
1981 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1982 // Force a fence to prevent any read before the write completes
1983 OrderAccess::fence();
1984 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1985 }
1986 }
1987
1988 // ----------------------------------------------------------------------------
1989 // Initialization
1990
1991 void SystemDictionary::initialize(TRAPS) {
1992 // Allocate arrays
1993 _placeholders = new PlaceholderTable(_placeholder_table_size);
1994 _number_of_modifications = 0;
1995 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1996 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1997 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1998 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1999
2000 // Allocate private object used as system class loader lock
2001 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2002 // Initialize basic classes
2003 initialize_preloaded_classes(CHECK);
2004 }
2005
2006 // Compact table of directions on the initialization of klasses:
2007 static const short wk_init_info[] = {
2008 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2009 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2010 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2011 | (int)SystemDictionary::option ),
2012 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2013 #undef WK_KLASS_INIT_INFO
2014 0
2015 };
2016
2017 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2018 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2019 int info = wk_init_info[id - FIRST_WKID];
2020 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2021 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2022 InstanceKlass** klassp = &_well_known_klasses[id];
2023
2024 bool must_load;
2025 #if INCLUDE_JVMCI
2026 if (EnableJVMCI) {
2027 // If JVMCI is enabled we require its classes to be found.
2028 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2029 } else
2030 #endif
2031 {
2032 must_load = (init_opt < SystemDictionary::Opt);
2033 }
2034
2035 if ((*klassp) == NULL) {
2036 Klass* k;
2037 if (must_load) {
2038 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2039 } else {
2040 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2041 }
2042 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2043 }
2044 return ((*klassp) != NULL);
2045 }
2046
2047 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2048 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2049 for (int id = (int)start_id; id < (int)limit_id; id++) {
2050 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2051 int info = wk_init_info[id - FIRST_WKID];
2052 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2053 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2054
2055 initialize_wk_klass((WKID)id, opt, CHECK);
2056 }
2057
2058 // move the starting value forward to the limit:
2059 start_id = limit_id;
2060 }
2061
2062 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2063 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2064
2065 // Create the ModuleEntry for java.base. This call needs to be done here,
2066 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2067 ClassLoader::classLoader_init2(CHECK);
2068
2069 // Preload commonly used klasses
2070 WKID scan = FIRST_WKID;
2071 // first do Object, then String, Class
2072 #if INCLUDE_CDS
2073 if (UseSharedSpaces) {
2074 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2075 // Initialize the constant pool for the Object_class
2076 Object_klass()->constants()->restore_unshareable_info(CHECK);
2077 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2078 } else
2079 #endif
2080 {
2081 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2082 }
2083
2084 // Calculate offsets for String and Class classes since they are loaded and
2085 // can be used after this point.
2086 java_lang_String::compute_offsets();
2087 java_lang_Class::compute_offsets();
2088
2089 // Fixup mirrors for classes loaded before java.lang.Class.
2090 // These calls iterate over the objects currently in the perm gen
2091 // so calling them at this point is matters (not before when there
2092 // are fewer objects and not later after there are more objects
2093 // in the perm gen.
2094 Universe::initialize_basic_type_mirrors(CHECK);
2095 Universe::fixup_mirrors(CHECK);
2096
2097 // do a bunch more:
2098 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2099
2100 // Preload ref klasses and set reference types
2101 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2102 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2103
2104 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2105 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2106 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2107 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2108 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2109
2110 // JSR 292 classes
2111 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2112 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2113 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2114 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2115 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2116
2117 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2118 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2119 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2120 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2121 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2122 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2123 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2124 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2125 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2126 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2127
2128 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2129 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2130 _has_loadClassInternal = (method != NULL);
2131 }
2132 { // Compute whether we should use checkPackageAccess or NOT
2133 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2134 _has_checkPackageAccess = (method != NULL);
2135 }
2136 }
2137
2138 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2139 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2140 BasicType SystemDictionary::box_klass_type(Klass* k) {
2141 assert(k != NULL, "");
2142 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2143 if (_box_klasses[i] == k)
2144 return (BasicType)i;
2145 }
2146 return T_OBJECT;
2147 }
2148
2149 // Constraints on class loaders. The details of the algorithm can be
2150 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2151 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2152 // that the dictionary needs to maintain a set of contraints that
2153 // must be satisfied by all classes in the dictionary.
2154 // if defining is true, then LinkageError if already in dictionary
2155 // if initiating loader, then ok if InstanceKlass matches existing entry
2156
2157 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2158 InstanceKlass* k,
2159 Handle class_loader, bool defining,
2160 TRAPS) {
2161 const char *linkage_error1 = NULL;
2162 const char *linkage_error2 = NULL;
2163 {
2164 Symbol* name = k->name();
2165 ClassLoaderData *loader_data = class_loader_data(class_loader);
2166
2167 MutexLocker mu(SystemDictionary_lock, THREAD);
2168
2169 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2170 if (check != NULL) {
2171 // if different InstanceKlass - duplicate class definition,
2172 // else - ok, class loaded by a different thread in parallel,
2173 // we should only have found it if it was done loading and ok to use
2174 // dictionary only holds instance classes, placeholders
2175 // also holds array classes
2176
2177 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2178 if ((defining == true) || (k != check)) {
2179 linkage_error1 = "loader (instance of ";
2180 linkage_error2 = "): attempted duplicate class definition for name: \"";
2181 } else {
2182 return;
2183 }
2184 }
2185
2186 #ifdef ASSERT
2187 Symbol* ph_check = find_placeholder(name, loader_data);
2188 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2189 #endif
2190
2191 if (linkage_error1 == NULL) {
2192 if (constraints()->check_or_update(k, class_loader, name) == false) {
2193 linkage_error1 = "loader constraint violation: loader (instance of ";
2194 linkage_error2 = ") previously initiated loading for a different type with name \"";
2195 }
2196 }
2197 }
2198
2199 // Throw error now if needed (cannot throw while holding
2200 // SystemDictionary_lock because of rank ordering)
2201
2202 if (linkage_error1) {
2203 ResourceMark rm(THREAD);
2204 const char* class_loader_name = loader_name(class_loader());
2205 char* type_name = k->name()->as_C_string();
2206 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2207 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2208 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2209 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2210 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2211 }
2212 }
2213
2214
2215 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2216 // have been called.
2217 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2218 int p_index, unsigned int p_hash,
2219 InstanceKlass* k,
2220 Handle class_loader,
2221 TRAPS) {
2222 // Compile_lock prevents systemDictionary updates during compilations
2223 assert_locked_or_safepoint(Compile_lock);
2224 Symbol* name = k->name();
2225 ClassLoaderData *loader_data = class_loader_data(class_loader);
2226
2227 {
2228 MutexLocker mu1(SystemDictionary_lock, THREAD);
2229
2230 // See whether biased locking is enabled and if so set it for this
2231 // klass.
2232 // Note that this must be done past the last potential blocking
2233 // point / safepoint. We enable biased locking lazily using a
2234 // VM_Operation to iterate the SystemDictionary and installing the
2235 // biasable mark word into each InstanceKlass's prototype header.
2236 // To avoid race conditions where we accidentally miss enabling the
2237 // optimization for one class in the process of being added to the
2238 // dictionary, we must not safepoint after the test of
2239 // BiasedLocking::enabled().
2240 if (UseBiasedLocking && BiasedLocking::enabled()) {
2241 // Set biased locking bit for all loaded classes; it will be
2242 // cleared if revocation occurs too often for this type
2243 // NOTE that we must only do this when the class is initally
2244 // defined, not each time it is referenced from a new class loader
2245 if (k->class_loader() == class_loader()) {
2246 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2247 }
2248 }
2249
2250 // Make a new dictionary entry.
2251 Dictionary* dictionary = loader_data->dictionary();
2252 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2253 if (sd_check == NULL) {
2254 dictionary->add_klass(d_index, d_hash, name, k);
2255 notice_modification();
2256 }
2257 #ifdef ASSERT
2258 sd_check = find_class(d_index, d_hash, name, dictionary);
2259 assert (sd_check != NULL, "should have entry in dictionary");
2260 // Note: there may be a placeholder entry: for circularity testing
2261 // or for parallel defines
2262 #endif
2263 SystemDictionary_lock->notify_all();
2264 }
2265 }
2266
2267
2268 // Try to find a class name using the loader constraints. The
2269 // loader constraints might know about a class that isn't fully loaded
2270 // yet and these will be ignored.
2271 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2272 Symbol* class_name, Handle class_loader, TRAPS) {
2273
2274 // First see if it has been loaded directly.
2275 // Force the protection domain to be null. (This removes protection checks.)
2276 Handle no_protection_domain;
2277 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2278 no_protection_domain, CHECK_NULL);
2279 if (klass != NULL)
2280 return klass;
2281
2282 // Now look to see if it has been loaded elsewhere, and is subject to
2283 // a loader constraint that would require this loader to return the
2284 // klass that is already loaded.
2285 if (FieldType::is_array(class_name)) {
2286 // For array classes, their Klass*s are not kept in the
2287 // constraint table. The element Klass*s are.
2288 FieldArrayInfo fd;
2289 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2290 if (t != T_OBJECT) {
2291 klass = Universe::typeArrayKlassObj(t);
2292 } else {
2293 MutexLocker mu(SystemDictionary_lock, THREAD);
2294 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2295 }
2296 // If element class already loaded, allocate array klass
2297 if (klass != NULL) {
2298 klass = klass->array_klass_or_null(fd.dimension());
2299 }
2300 } else {
2301 MutexLocker mu(SystemDictionary_lock, THREAD);
2302 // Non-array classes are easy: simply check the constraint table.
2303 klass = constraints()->find_constrained_klass(class_name, class_loader);
2304 }
2305
2306 return klass;
2307 }
2308
2309
2310 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2311 Handle class_loader1,
2312 Handle class_loader2,
2313 Thread* THREAD) {
2314 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2315 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2316
2317 Symbol* constraint_name = NULL;
2318 if (!FieldType::is_array(class_name)) {
2319 constraint_name = class_name;
2320 } else {
2321 // For array classes, their Klass*s are not kept in the
2322 // constraint table. The element classes are.
2323 FieldArrayInfo fd;
2324 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2325 // primitive types always pass
2326 if (t != T_OBJECT) {
2327 return true;
2328 } else {
2329 constraint_name = fd.object_key();
2330 }
2331 }
2332
2333 Dictionary* dictionary1 = loader_data1->dictionary();
2334 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2335 int d_index1 = dictionary1->hash_to_index(d_hash1);
2336
2337 Dictionary* dictionary2 = loader_data2->dictionary();
2338 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2339 int d_index2 = dictionary2->hash_to_index(d_hash2);
2340
2341 {
2342 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2343 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2344 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2345 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2346 klass2, class_loader2);
2347 }
2348 }
2349
2350 // Add entry to resolution error table to record the error when the first
2351 // attempt to resolve a reference to a class has failed.
2352 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2353 Symbol* error, Symbol* message) {
2354 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2355 int index = resolution_errors()->hash_to_index(hash);
2356 {
2357 MutexLocker ml(SystemDictionary_lock, Thread::current());
2358 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2359 }
2360 }
2361
2362 // Delete a resolution error for RedefineClasses for a constant pool is going away
2363 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2364 resolution_errors()->delete_entry(pool);
2365 }
2366
2367 // Lookup resolution error table. Returns error if found, otherwise NULL.
2368 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2369 Symbol** message) {
2370 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2371 int index = resolution_errors()->hash_to_index(hash);
2372 {
2373 MutexLocker ml(SystemDictionary_lock, Thread::current());
2374 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2375 if (entry != NULL) {
2376 *message = entry->message();
2377 return entry->error();
2378 } else {
2379 return NULL;
2380 }
2381 }
2382 }
2383
2384
2385 // Signature constraints ensure that callers and callees agree about
2386 // the meaning of type names in their signatures. This routine is the
2387 // intake for constraints. It collects them from several places:
2388 //
2389 // * LinkResolver::resolve_method (if check_access is true) requires
2390 // that the resolving class (the caller) and the defining class of
2391 // the resolved method (the callee) agree on each type in the
2392 // method's signature.
2393 //
2394 // * LinkResolver::resolve_interface_method performs exactly the same
2395 // checks.
2396 //
2397 // * LinkResolver::resolve_field requires that the constant pool
2398 // attempting to link to a field agree with the field's defining
2399 // class about the type of the field signature.
2400 //
2401 // * klassVtable::initialize_vtable requires that, when a class
2402 // overrides a vtable entry allocated by a superclass, that the
2403 // overriding method (i.e., the callee) agree with the superclass
2404 // on each type in the method's signature.
2405 //
2406 // * klassItable::initialize_itable requires that, when a class fills
2407 // in its itables, for each non-abstract method installed in an
2408 // itable, the method (i.e., the callee) agree with the interface
2409 // on each type in the method's signature.
2410 //
2411 // All those methods have a boolean (check_access, checkconstraints)
2412 // which turns off the checks. This is used from specialized contexts
2413 // such as bootstrapping, dumping, and debugging.
2414 //
2415 // No direct constraint is placed between the class and its
2416 // supertypes. Constraints are only placed along linked relations
2417 // between callers and callees. When a method overrides or implements
2418 // an abstract method in a supertype (superclass or interface), the
2419 // constraints are placed as if the supertype were the caller to the
2420 // overriding method. (This works well, since callers to the
2421 // supertype have already established agreement between themselves and
2422 // the supertype.) As a result of all this, a class can disagree with
2423 // its supertype about the meaning of a type name, as long as that
2424 // class neither calls a relevant method of the supertype, nor is
2425 // called (perhaps via an override) from the supertype.
2426 //
2427 //
2428 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2429 //
2430 // Make sure all class components (including arrays) in the given
2431 // signature will be resolved to the same class in both loaders.
2432 // Returns the name of the type that failed a loader constraint check, or
2433 // NULL if no constraint failed. No exception except OOME is thrown.
2434 // Arrays are not added to the loader constraint table, their elements are.
2435 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2436 Handle loader1, Handle loader2,
2437 bool is_method, TRAPS) {
2438 // Nothing to do if loaders are the same.
2439 if (loader1() == loader2()) {
2440 return NULL;
2441 }
2442
2443 SignatureStream sig_strm(signature, is_method);
2444 while (!sig_strm.is_done()) {
2445 if (sig_strm.is_object()) {
2446 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2447 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2448 return sig;
2449 }
2450 }
2451 sig_strm.next();
2452 }
2453 return NULL;
2454 }
2455
2456
2457 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2458 Symbol* signature,
2459 TRAPS) {
2460 methodHandle empty;
2461 assert(MethodHandles::is_signature_polymorphic(iid) &&
2462 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2463 iid != vmIntrinsics::_invokeGeneric,
2464 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2465
2466 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2467 int index = invoke_method_table()->hash_to_index(hash);
2468 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2469 methodHandle m;
2470 if (spe == NULL || spe->method() == NULL) {
2471 spe = NULL;
2472 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2473 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2474 if (!Arguments::is_interpreter_only()) {
2475 // Generate a compiled form of the MH intrinsic.
2476 AdapterHandlerLibrary::create_native_wrapper(m);
2477 // Check if have the compiled code.
2478 if (!m->has_compiled_code()) {
2479 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2480 "Out of space in CodeCache for method handle intrinsic", empty);
2481 }
2482 }
2483 // Now grab the lock. We might have to throw away the new method,
2484 // if a racing thread has managed to install one at the same time.
2485 {
2486 MutexLocker ml(SystemDictionary_lock, THREAD);
2487 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2488 if (spe == NULL)
2489 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2490 if (spe->method() == NULL)
2491 spe->set_method(m());
2492 }
2493 }
2494
2495 assert(spe != NULL && spe->method() != NULL, "");
2496 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2497 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2498 "MH intrinsic invariant");
2499 return spe->method();
2500 }
2501
2502 // Helper for unpacking the return value from linkMethod and linkCallSite.
2503 static methodHandle unpack_method_and_appendix(Handle mname,
2504 Klass* accessing_klass,
2505 objArrayHandle appendix_box,
2506 Handle* appendix_result,
2507 TRAPS) {
2508 methodHandle empty;
2509 if (mname.not_null()) {
2510 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2511 if (m != NULL) {
2512 oop appendix = appendix_box->obj_at(0);
2513 if (TraceMethodHandles) {
2514 #ifndef PRODUCT
2515 ttyLocker ttyl;
2516 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2517 m->print();
2518 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2519 tty->cr();
2520 #endif //PRODUCT
2521 }
2522 (*appendix_result) = Handle(THREAD, appendix);
2523 // the target is stored in the cpCache and if a reference to this
2524 // MethodName is dropped we need a way to make sure the
2525 // class_loader containing this method is kept alive.
2526 // FIXME: the appendix might also preserve this dependency.
2527 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2528 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2529 return methodHandle(THREAD, m);
2530 }
2531 }
2532 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2533 return empty;
2534 }
2535
2536 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2537 Symbol* name,
2538 Symbol* signature,
2539 Klass* accessing_klass,
2540 Handle *appendix_result,
2541 Handle *method_type_result,
2542 TRAPS) {
2543 methodHandle empty;
2544 assert(THREAD->can_call_java() ,"");
2545 Handle method_type =
2546 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2547
2548 int ref_kind = JVM_REF_invokeVirtual;
2549 oop name_oop = StringTable::intern(name, CHECK_(empty));
2550 Handle name_str (THREAD, name_oop);
2551 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2552 assert(appendix_box->obj_at(0) == NULL, "");
2553
2554 // This should not happen. JDK code should take care of that.
2555 if (accessing_klass == NULL || method_type.is_null()) {
2556 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2557 }
2558
2559 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2560 JavaCallArguments args;
2561 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2562 args.push_int(ref_kind);
2563 args.push_oop(Handle(THREAD, klass->java_mirror()));
2564 args.push_oop(name_str);
2565 args.push_oop(method_type);
2566 args.push_oop(appendix_box);
2567 JavaValue result(T_OBJECT);
2568 JavaCalls::call_static(&result,
2569 SystemDictionary::MethodHandleNatives_klass(),
2570 vmSymbols::linkMethod_name(),
2571 vmSymbols::linkMethod_signature(),
2572 &args, CHECK_(empty));
2573 Handle mname(THREAD, (oop) result.get_jobject());
2574 (*method_type_result) = method_type;
2575 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2576 }
2577
2578 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2579 // We must ensure that all class loaders everywhere will reach this class, for any client.
2580 // This is a safe bet for public classes in java.lang, such as Object and String.
2581 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2582 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2583 static bool is_always_visible_class(oop mirror) {
2584 Klass* klass = java_lang_Class::as_Klass(mirror);
2585 if (klass->is_objArray_klass()) {
2586 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2587 }
2588 if (klass->is_typeArray_klass()) {
2589 return true; // primitive array
2590 }
2591 assert(klass->is_instance_klass(), "%s", klass->external_name());
2592 return klass->is_public() &&
2593 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2594 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2595 }
2596
2597 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2598 // signature, as interpreted relative to the given class loader.
2599 // Because of class loader constraints, all method handle usage must be
2600 // consistent with this loader.
2601 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2602 Klass* accessing_klass,
2603 TRAPS) {
2604 Handle empty;
2605 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2606 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2607 int index = invoke_method_table()->hash_to_index(hash);
2608 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2609 if (spe != NULL && spe->method_type() != NULL) {
2610 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2611 return Handle(THREAD, spe->method_type());
2612 } else if (!THREAD->can_call_java()) {
2613 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2614 return Handle(); // do not attempt from within compiler, unless it was cached
2615 }
2616
2617 Handle class_loader, protection_domain;
2618 if (accessing_klass != NULL) {
2619 class_loader = Handle(THREAD, accessing_klass->class_loader());
2620 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2621 }
2622 bool can_be_cached = true;
2623 int npts = ArgumentCount(signature).size();
2624 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2625 int arg = 0;
2626 Handle rt; // the return type from the signature
2627 ResourceMark rm(THREAD);
2628 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2629 oop mirror = NULL;
2630 if (can_be_cached) {
2631 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2632 mirror = ss.as_java_mirror(Handle(), Handle(),
2633 SignatureStream::ReturnNull, CHECK_(empty));
2634 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2635 // Fall back to accessing_klass context.
2636 can_be_cached = false;
2637 }
2638 }
2639 if (!can_be_cached) {
2640 // Resolve, throwing a real error if it doesn't work.
2641 mirror = ss.as_java_mirror(class_loader, protection_domain,
2642 SignatureStream::NCDFError, CHECK_(empty));
2643 }
2644 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2645 if (ss.at_return_type())
2646 rt = Handle(THREAD, mirror);
2647 else
2648 pts->obj_at_put(arg++, mirror);
2649
2650 // Check accessibility.
2651 if (ss.is_object() && accessing_klass != NULL) {
2652 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2653 mirror = NULL; // safety
2654 // Emulate ConstantPool::verify_constant_pool_resolve.
2655 if (sel_klass->is_objArray_klass())
2656 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2657 if (sel_klass->is_instance_klass()) {
2658 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2659 }
2660 }
2661 }
2662 assert(arg == npts, "");
2663
2664 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2665 JavaCallArguments args(Handle(THREAD, rt()));
2666 args.push_oop(pts);
2667 JavaValue result(T_OBJECT);
2668 JavaCalls::call_static(&result,
2669 SystemDictionary::MethodHandleNatives_klass(),
2670 vmSymbols::findMethodHandleType_name(),
2671 vmSymbols::findMethodHandleType_signature(),
2672 &args, CHECK_(empty));
2673 Handle method_type(THREAD, (oop) result.get_jobject());
2674
2675 if (can_be_cached) {
2676 // We can cache this MethodType inside the JVM.
2677 MutexLocker ml(SystemDictionary_lock, THREAD);
2678 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2679 if (spe == NULL)
2680 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2681 if (spe->method_type() == NULL) {
2682 spe->set_method_type(method_type());
2683 }
2684 }
2685
2686 // report back to the caller with the MethodType
2687 return method_type;
2688 }
2689
2690 // Ask Java code to find or construct a method handle constant.
2691 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2692 int ref_kind, //e.g., JVM_REF_invokeVirtual
2693 Klass* callee,
2694 Symbol* name_sym,
2695 Symbol* signature,
2696 TRAPS) {
2697 Handle empty;
2698 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2699 Handle type;
2700 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2701 type = find_method_handle_type(signature, caller, CHECK_(empty));
2702 } else if (caller == NULL) {
2703 // This should not happen. JDK code should take care of that.
2704 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2705 } else {
2706 ResourceMark rm(THREAD);
2707 SignatureStream ss(signature, false);
2708 if (!ss.is_done()) {
2709 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2710 Handle(THREAD, caller->protection_domain()),
2711 SignatureStream::NCDFError, CHECK_(empty));
2712 type = Handle(THREAD, mirror);
2713 ss.next();
2714 if (!ss.is_done()) type = Handle(); // error!
2715 }
2716 }
2717 if (type.is_null()) {
2718 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2719 }
2720
2721 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2722 JavaCallArguments args;
2723 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2724 args.push_int(ref_kind);
2725 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2726 args.push_oop(name);
2727 args.push_oop(type);
2728 JavaValue result(T_OBJECT);
2729 JavaCalls::call_static(&result,
2730 SystemDictionary::MethodHandleNatives_klass(),
2731 vmSymbols::linkMethodHandleConstant_name(),
2732 vmSymbols::linkMethodHandleConstant_signature(),
2733 &args, CHECK_(empty));
2734 return Handle(THREAD, (oop) result.get_jobject());
2735 }
2736
2737 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2738 // name and signature, as interpreted relative to the given class loader.
2739 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2740 Handle bootstrap_specifier,
2741 Symbol* name,
2742 Symbol* type,
2743 Handle *appendix_result,
2744 Handle *method_type_result,
2745 TRAPS) {
2746 methodHandle empty;
2747 Handle bsm, info;
2748 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2749 bsm = bootstrap_specifier;
2750 } else {
2751 assert(bootstrap_specifier->is_objArray(), "");
2752 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2753 int len = args->length();
2754 assert(len >= 1, "");
2755 bsm = Handle(THREAD, args->obj_at(0));
2756 if (len > 1) {
2757 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2758 for (int i = 1; i < len; i++)
2759 args1->obj_at_put(i-1, args->obj_at(i));
2760 info = Handle(THREAD, args1);
2761 }
2762 }
2763 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2764 "caller must supply a valid BSM");
2765
2766 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2767 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2768
2769 // This should not happen. JDK code should take care of that.
2770 if (caller == NULL || method_type.is_null()) {
2771 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2772 }
2773
2774 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2775 assert(appendix_box->obj_at(0) == NULL, "");
2776
2777 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2778 JavaCallArguments args;
2779 args.push_oop(Handle(THREAD, caller->java_mirror()));
2780 args.push_oop(bsm);
2781 args.push_oop(method_name);
2782 args.push_oop(method_type);
2783 args.push_oop(info);
2784 args.push_oop(appendix_box);
2785 JavaValue result(T_OBJECT);
2786 JavaCalls::call_static(&result,
2787 SystemDictionary::MethodHandleNatives_klass(),
2788 vmSymbols::linkCallSite_name(),
2789 vmSymbols::linkCallSite_signature(),
2790 &args, CHECK_(empty));
2791 Handle mname(THREAD, (oop) result.get_jobject());
2792 (*method_type_result) = method_type;
2793 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2794 }
2795
2796 // Protection domain cache table handling
2797
2798 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2799 return _pd_cache_table->get(protection_domain);
2800 }
2801
2802 void SystemDictionary::reorder_dictionary_for_sharing() {
2803 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2804 }
2805
2806 size_t SystemDictionary::count_bytes_for_buckets() {
2807 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2808 }
2809
2810 size_t SystemDictionary::count_bytes_for_table() {
2811 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2812 }
2813
2814 void SystemDictionary::copy_buckets(char* top, char* end) {
2815 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2816 }
2817
2818 void SystemDictionary::copy_table(char* top, char* end) {
2819 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2820 }
2821
2822 // ----------------------------------------------------------------------------
2823 void SystemDictionary::print_shared(outputStream *st) {
2824 shared_dictionary()->print_on(st);
2825 }
2826
2827 void SystemDictionary::print_on(outputStream *st) {
2828 if (shared_dictionary() != NULL) {
2829 st->print_cr("Shared Dictionary");
2830 shared_dictionary()->print_on(st);
2831 st->cr();
2832 }
2833
2834 GCMutexLocker mu(SystemDictionary_lock);
2835
2836 ClassLoaderDataGraph::print_dictionary(st);
2837
2838 // Placeholders
2839 placeholders()->print_on(st);
2840 st->cr();
2841
2842 // loader constraints - print under SD_lock
2843 constraints()->print_on(st);
2844 st->cr();
2845
2846 _pd_cache_table->print_on(st);
2847 st->cr();
2848 }
2849
2850 void SystemDictionary::verify() {
2851 guarantee(constraints() != NULL,
2852 "Verify of loader constraints failed");
2853 guarantee(placeholders()->number_of_entries() >= 0,
2854 "Verify of placeholders failed");
2855
2856 GCMutexLocker mu(SystemDictionary_lock);
2857
2858 // Verify dictionary
2859 ClassLoaderDataGraph::verify_dictionary();
2860
2861 placeholders()->verify();
2862
2863 // Verify constraint table
2864 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2865 constraints()->verify(placeholders());
2866
2867 _pd_cache_table->verify();
2868 }
2869
2870 void SystemDictionary::dump(outputStream *st, bool verbose) {
2871 assert_locked_or_safepoint(SystemDictionary_lock);
2872 if (verbose) {
2873 print_on(st);
2874 } else {
2875 if (shared_dictionary() != NULL) {
2876 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2877 }
2878 ClassLoaderDataGraph::print_dictionary_statistics(st);
2879 placeholders()->print_table_statistics(st, "Placeholder Table");
2880 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2881 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2882 }
2883 }
2884
2885 // Utility for dumping dictionaries.
2886 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2887 DCmdWithParser(output, heap),
2888 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2889 "BOOLEAN", false, "false") {
2890 _dcmdparser.add_dcmd_option(&_verbose);
2891 }
2892
2893 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2894 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2895 _verbose.value());
2896 VMThread::execute(&dumper);
2897 }
2898
2899 int SystemDictionaryDCmd::num_arguments() {
2900 ResourceMark rm;
2901 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2902 if (dcmd != NULL) {
2903 DCmdMark mark(dcmd);
2904 return dcmd->_dcmdparser.num_arguments();
2905 } else {
2906 return 0;
2907 }
2908 }
2909
2910
2911 // caller needs ResourceMark
2912 const char* SystemDictionary::loader_name(const oop loader) {
2913 return ((loader) == NULL ? "<bootloader>" :
2914 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2915 }
2916
2917 // caller needs ResourceMark
2918 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2919 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2920 SystemDictionary::loader_name(loader_data->class_loader()));
2921 }