1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/method.inline.hpp"
60 #include "oops/methodData.hpp"
61 #include "oops/objArrayKlass.hpp"
62 #include "oops/objArrayOop.inline.hpp"
63 #include "oops/oop.inline.hpp"
64 #include "oops/symbol.hpp"
65 #include "oops/typeArrayKlass.hpp"
66 #include "prims/jvmtiEnvBase.hpp"
67 #include "prims/resolvedMethodTable.hpp"
68 #include "prims/methodHandles.hpp"
69 #include "runtime/arguments.hpp"
70 #include "runtime/arguments_ext.hpp"
71 #include "runtime/biasedLocking.hpp"
72 #include "runtime/fieldType.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/java.hpp"
75 #include "runtime/javaCalls.hpp"
76 #include "runtime/mutexLocker.hpp"
77 #include "runtime/orderAccess.inline.hpp"
78 #include "runtime/signature.hpp"
79 #include "services/classLoadingService.hpp"
80 #include "services/diagnosticCommand.hpp"
81 #include "services/threadService.hpp"
82 #include "trace/tracing.hpp"
83 #include "utilities/macros.hpp"
84 #if INCLUDE_CDS
85 #include "classfile/sharedClassUtil.hpp"
86 #include "classfile/systemDictionaryShared.hpp"
87 #endif
88 #if INCLUDE_JVMCI
89 #include "jvmci/jvmciRuntime.hpp"
90 #endif
91
92 PlaceholderTable* SystemDictionary::_placeholders = NULL;
93 Dictionary* SystemDictionary::_shared_dictionary = NULL;
94 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
95 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
96 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
97 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
98
99 int SystemDictionary::_number_of_modifications = 0;
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108 oop SystemDictionary::_java_platform_loader = NULL;
109
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149
150 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
151 }
152
153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
155 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
156 }
157
158 // ----------------------------------------------------------------------------
159 // Parallel class loading check
160
161 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
162 if (class_loader.is_null()) return true;
163 if (AlwaysLockClassLoader) return false;
164 return java_lang_ClassLoader::parallelCapable(class_loader());
165 }
166 // ----------------------------------------------------------------------------
167 // ParallelDefineClass flag does not apply to bootclass loader
168 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
169 if (class_loader.is_null()) return false;
170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
171 return true;
172 }
173 return false;
174 }
175
176 // Returns true if the passed class loader is the builtin application class loader
177 // or a custom system class loader. A customer system class loader can be
178 // specified via -Djava.system.class.loader.
179 bool SystemDictionary::is_system_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
184 class_loader == _java_system_loader);
185 }
186
187 // Returns true if the passed class loader is the platform class loader.
188 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
189 if (class_loader == NULL) {
190 return false;
191 }
192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
193 }
194
195 // ----------------------------------------------------------------------------
196 // Resolving of classes
197
198 // Forwards to resolve_or_null
199
200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
202 if (HAS_PENDING_EXCEPTION || klass == NULL) {
203 // can return a null klass
204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
205 }
206 return klass;
207 }
208
209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
210 bool throw_error,
211 Klass* klass, TRAPS) {
212 if (HAS_PENDING_EXCEPTION) {
213 // If we have a pending exception we forward it to the caller, unless throw_error is true,
214 // in which case we have to check whether the pending exception is a ClassNotFoundException,
215 // and if so convert it to a NoClassDefFoundError
216 // And chain the original ClassNotFoundException
217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
218 ResourceMark rm(THREAD);
219 assert(klass == NULL, "Should not have result with exception pending");
220 Handle e(THREAD, PENDING_EXCEPTION);
221 CLEAR_PENDING_EXCEPTION;
222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
223 } else {
224 return NULL;
225 }
226 }
227 // Class not found, throw appropriate error or exception depending on value of throw_error
228 if (klass == NULL) {
229 ResourceMark rm(THREAD);
230 if (throw_error) {
231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
232 } else {
233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
234 }
235 }
236 return klass;
237 }
238
239
240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
241 bool throw_error, TRAPS)
242 {
243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
244 }
245
246
247 // Forwards to resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 assert(THREAD->can_call_java(),
251 "can not load classes with compiler thread: class=%s, classloader=%s",
252 class_name->as_C_string(),
253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
254 if (FieldType::is_array(class_name)) {
255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 } else if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2, CHECK_NULL);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* class_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for CDS dump time.
348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(SystemDictionary_lock, THREAD);
381 Klass* childk = find_class(d_hash, child_name, dictionary);
382 Klass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if class_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->super()) != NULL) &&
391
392 ((quicksuperk->name() == class_name) &&
393 (quicksuperk->class_loader() == class_loader()))) {
394 return quicksuperk;
395 } else {
396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
398 throw_circularity_error = true;
399 }
400 }
401 if (!throw_circularity_error) {
402 // Be careful not to exit resolve_super
403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
404 }
405 }
406 if (throw_circularity_error) {
407 ResourceMark rm(THREAD);
408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
409 }
410
411 // java.lang.Object should have been found above
412 assert(class_name != NULL, "null super class for resolving");
413 // Resolve the super class or interface, check results on return
414 Klass* superk = SystemDictionary::resolve_or_null(class_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 superk = handle_resolution_exception(class_name, true, superk, THREAD);
433 }
434
435 return superk;
436 }
437
438 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
439 Handle class_loader,
440 Handle protection_domain,
441 TRAPS) {
442 if(!has_checkPackageAccess()) return;
443
444 // Now we have to call back to java to check if the initating class has access
445 JavaValue result(T_VOID);
446 LogTarget(Debug, protectiondomain) lt;
447 if (lt.is_enabled()) {
448 ResourceMark rm;
449 // Print out trace information
450 LogStream ls(lt);
451 ls.print_cr("Checking package access");
452 ls.print("class loader: "); class_loader()->print_value_on(&ls);
453 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
454 ls.print(" loading: "); klass->print_value_on(&ls);
455 ls.cr();
456 }
457
458 // This handle and the class_loader handle passed in keeps this class from
459 // being unloaded through several GC points.
460 // The class_loader handle passed in is the initiating loader.
461 Handle mirror(THREAD, klass->java_mirror());
462
463 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
464 JavaCalls::call_special(&result,
465 class_loader,
466 system_loader,
467 vmSymbols::checkPackageAccess_name(),
468 vmSymbols::class_protectiondomain_signature(),
469 mirror,
470 protection_domain,
471 THREAD);
472
473 if (HAS_PENDING_EXCEPTION) {
474 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
475 } else {
476 log_debug(protectiondomain)("granted");
477 }
478
479 if (HAS_PENDING_EXCEPTION) return;
480
481 // If no exception has been thrown, we have validated the protection domain
482 // Insert the protection domain of the initiating class into the set.
483 {
484 ClassLoaderData* loader_data = class_loader_data(class_loader);
485 Dictionary* dictionary = loader_data->dictionary();
486
487 Symbol* kn = klass->name();
488 unsigned int d_hash = dictionary->compute_hash(kn);
489
490 MutexLocker mu(SystemDictionary_lock, THREAD);
491 int d_index = dictionary->hash_to_index(d_hash);
492 dictionary->add_protection_domain(d_index, d_hash, klass,
493 protection_domain, THREAD);
494 }
495 }
496
497 // We only get here if this thread finds that another thread
498 // has already claimed the placeholder token for the current operation,
499 // but that other thread either never owned or gave up the
500 // object lock
501 // Waits on SystemDictionary_lock to indicate placeholder table updated
502 // On return, caller must recheck placeholder table state
503 //
504 // We only get here if
505 // 1) custom classLoader, i.e. not bootstrap classloader
506 // 2) custom classLoader has broken the class loader objectLock
507 // so another thread got here in parallel
508 //
509 // lockObject must be held.
510 // Complicated dance due to lock ordering:
511 // Must first release the classloader object lock to
512 // allow initial definer to complete the class definition
513 // and to avoid deadlock
514 // Reclaim classloader lock object with same original recursion count
515 // Must release SystemDictionary_lock after notify, since
516 // class loader lock must be claimed before SystemDictionary_lock
517 // to prevent deadlocks
518 //
519 // The notify allows applications that did an untimed wait() on
520 // the classloader object lock to not hang.
521 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
522 assert_lock_strong(SystemDictionary_lock);
523
524 bool calledholdinglock
525 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
526 assert(calledholdinglock,"must hold lock for notify");
527 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
528 ObjectSynchronizer::notifyall(lockObject, THREAD);
529 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
530 SystemDictionary_lock->wait();
531 SystemDictionary_lock->unlock();
532 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
533 SystemDictionary_lock->lock();
534 }
535
536 // If the class in is in the placeholder table, class loading is in progress
537 // For cases where the application changes threads to load classes, it
538 // is critical to ClassCircularity detection that we try loading
539 // the superclass on the same thread internally, so we do parallel
540 // super class loading here.
541 // This also is critical in cases where the original thread gets stalled
542 // even in non-circularity situations.
543 // Note: must call resolve_super_or_fail even if null super -
544 // to force placeholder entry creation for this class for circularity detection
545 // Caller must check for pending exception
546 // Returns non-null Klass* if other thread has completed load
547 // and we are done,
548 // If return null Klass* and no pending exception, the caller must load the class
549 InstanceKlass* SystemDictionary::handle_parallel_super_load(
550 Symbol* name, Symbol* superclassname, Handle class_loader,
551 Handle protection_domain, Handle lockObject, TRAPS) {
552
553 ClassLoaderData* loader_data = class_loader_data(class_loader);
554 Dictionary* dictionary = loader_data->dictionary();
555 unsigned int d_hash = dictionary->compute_hash(name);
556 unsigned int p_hash = placeholders()->compute_hash(name);
557 int p_index = placeholders()->hash_to_index(p_hash);
558
559 // superk is not used, resolve_super called for circularity check only
560 // This code is reached in two situations. One if this thread
561 // is loading the same class twice (e.g. ClassCircularity, or
562 // java.lang.instrument).
563 // The second is if another thread started the resolve_super first
564 // and has not yet finished.
565 // In both cases the original caller will clean up the placeholder
566 // entry on error.
567 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
568 superclassname,
569 class_loader,
570 protection_domain,
571 true,
572 CHECK_NULL);
573
574 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
575 // Serial class loaders and bootstrap classloader do wait for superclass loads
576 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
577 MutexLocker mu(SystemDictionary_lock, THREAD);
578 // Check if classloading completed while we were loading superclass or waiting
579 return find_class(d_hash, name, dictionary);
580 }
581
582 // must loop to both handle other placeholder updates
583 // and spurious notifications
584 bool super_load_in_progress = true;
585 PlaceholderEntry* placeholder;
586 while (super_load_in_progress) {
587 MutexLocker mu(SystemDictionary_lock, THREAD);
588 // Check if classloading completed while we were loading superclass or waiting
589 InstanceKlass* check = find_class(d_hash, name, dictionary);
590 if (check != NULL) {
591 // Klass is already loaded, so just return it
592 return check;
593 } else {
594 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
595 if (placeholder && placeholder->super_load_in_progress() ){
596 // We only get here if the application has released the
597 // classloader lock when another thread was in the middle of loading a
598 // superclass/superinterface for this class, and now
599 // this thread is also trying to load this class.
600 // To minimize surprises, the first thread that started to
601 // load a class should be the one to complete the loading
602 // with the classfile it initially expected.
603 // This logic has the current thread wait once it has done
604 // all the superclass/superinterface loading it can, until
605 // the original thread completes the class loading or fails
606 // If it completes we will use the resulting InstanceKlass
607 // which we will find below in the systemDictionary.
608 // We also get here for parallel bootstrap classloader
609 if (class_loader.is_null()) {
610 SystemDictionary_lock->wait();
611 } else {
612 double_lock_wait(lockObject, THREAD);
613 }
614 } else {
615 // If not in SD and not in PH, other thread's load must have failed
616 super_load_in_progress = false;
617 }
618 }
619 }
620 return NULL;
621 }
622
623 static void post_class_load_event(EventClassLoad* event,
624 const InstanceKlass* k,
625 const ClassLoaderData* init_cld) {
626 #if INCLUDE_TRACE
627 assert(event != NULL, "invariant");
628 assert(k != NULL, "invariant");
629 if (event->should_commit()) {
630 event->set_loadedClass(k);
631 event->set_definingClassLoader(k->class_loader_data());
632 event->set_initiatingClassLoader(init_cld);
633 event->commit();
634 }
635 #endif // INCLUDE_TRACE
636 }
637
638 static void class_define_event(InstanceKlass* k,
639 const ClassLoaderData* def_cld) {
640 #if INCLUDE_TRACE
641 EventClassDefine event;
642 if (event.should_commit()) {
643 event.set_definedClass(k);
644 event.set_definingClassLoader(def_cld);
645 event.commit();
646 }
647 #endif // INCLUDE_TRACE
648 }
649
650 // Be careful when modifying this code: once you have run
651 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
652 // you need to find_and_remove it before returning.
653 // So be careful to not exit with a CHECK_ macro betweeen these calls.
654 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
655 Handle class_loader,
656 Handle protection_domain,
657 TRAPS) {
658 assert(name != NULL && !FieldType::is_array(name) &&
659 !FieldType::is_obj(name), "invalid class name");
660
661 EventClassLoad class_load_start_event;
662
663 HandleMark hm(THREAD);
664
665 // Fix for 4474172; see evaluation for more details
666 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
667 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
668 Dictionary* dictionary = loader_data->dictionary();
669 unsigned int d_hash = dictionary->compute_hash(name);
670
671 // Do lookup to see if class already exist and the protection domain
672 // has the right access
673 // This call uses find which checks protection domain already matches
674 // All subsequent calls use find_class, and set has_loaded_class so that
675 // before we return a result we call out to java to check for valid protection domain
676 // to allow returning the Klass* and add it to the pd_set if it is valid
677 {
678 Klass* probe = dictionary->find(d_hash, name, protection_domain);
679 if (probe != NULL) return probe;
680 }
681
682 // Non-bootstrap class loaders will call out to class loader and
683 // define via jvm/jni_DefineClass which will acquire the
684 // class loader object lock to protect against multiple threads
685 // defining the class in parallel by accident.
686 // This lock must be acquired here so the waiter will find
687 // any successful result in the SystemDictionary and not attempt
688 // the define.
689 // ParallelCapable Classloaders and the bootstrap classloader
690 // do not acquire lock here.
691 bool DoObjectLock = true;
692 if (is_parallelCapable(class_loader)) {
693 DoObjectLock = false;
694 }
695
696 unsigned int p_hash = placeholders()->compute_hash(name);
697 int p_index = placeholders()->hash_to_index(p_hash);
698
699 // Class is not in SystemDictionary so we have to do loading.
700 // Make sure we are synchronized on the class loader before we proceed
701 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
702 check_loader_lock_contention(lockObject, THREAD);
703 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
704
705 // Check again (after locking) if class already exist in SystemDictionary
706 bool class_has_been_loaded = false;
707 bool super_load_in_progress = false;
708 bool havesupername = false;
709 InstanceKlass* k = NULL;
710 PlaceholderEntry* placeholder;
711 Symbol* superclassname = NULL;
712
713 {
714 MutexLocker mu(SystemDictionary_lock, THREAD);
715 InstanceKlass* check = find_class(d_hash, name, dictionary);
716 if (check != NULL) {
717 // Klass is already loaded, so just return it
718 class_has_been_loaded = true;
719 k = check;
720 } else {
721 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
722 if (placeholder && placeholder->super_load_in_progress()) {
723 super_load_in_progress = true;
724 if (placeholder->havesupername() == true) {
725 superclassname = placeholder->supername();
726 havesupername = true;
727 }
728 }
729 }
730 }
731
732 // If the class is in the placeholder table, class loading is in progress
733 if (super_load_in_progress && havesupername==true) {
734 k = handle_parallel_super_load(name,
735 superclassname,
736 class_loader,
737 protection_domain,
738 lockObject, THREAD);
739 if (HAS_PENDING_EXCEPTION) {
740 return NULL;
741 }
742 if (k != NULL) {
743 class_has_been_loaded = true;
744 }
745 }
746
747 bool throw_circularity_error = false;
748 if (!class_has_been_loaded) {
749 bool load_instance_added = false;
750
751 // add placeholder entry to record loading instance class
752 // Five cases:
753 // All cases need to prevent modifying bootclasssearchpath
754 // in parallel with a classload of same classname
755 // Redefineclasses uses existence of the placeholder for the duration
756 // of the class load to prevent concurrent redefinition of not completely
757 // defined classes.
758 // case 1. traditional classloaders that rely on the classloader object lock
759 // - no other need for LOAD_INSTANCE
760 // case 2. traditional classloaders that break the classloader object lock
761 // as a deadlock workaround. Detection of this case requires that
762 // this check is done while holding the classloader object lock,
763 // and that lock is still held when calling classloader's loadClass.
764 // For these classloaders, we ensure that the first requestor
765 // completes the load and other requestors wait for completion.
766 // case 3. Bootstrap classloader - don't own objectLocker
767 // This classloader supports parallelism at the classloader level,
768 // but only allows a single load of a class/classloader pair.
769 // No performance benefit and no deadlock issues.
770 // case 4. parallelCapable user level classloaders - without objectLocker
771 // Allow parallel classloading of a class/classloader pair
772
773 {
774 MutexLocker mu(SystemDictionary_lock, THREAD);
775 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
776 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
777 if (oldprobe) {
778 // only need check_seen_thread once, not on each loop
779 // 6341374 java/lang/Instrument with -Xcomp
780 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
781 throw_circularity_error = true;
782 } else {
783 // case 1: traditional: should never see load_in_progress.
784 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
785
786 // case 3: bootstrap classloader: prevent futile classloading,
787 // wait on first requestor
788 if (class_loader.is_null()) {
789 SystemDictionary_lock->wait();
790 } else {
791 // case 2: traditional with broken classloader lock. wait on first
792 // requestor.
793 double_lock_wait(lockObject, THREAD);
794 }
795 // Check if classloading completed while we were waiting
796 InstanceKlass* check = find_class(d_hash, name, dictionary);
797 if (check != NULL) {
798 // Klass is already loaded, so just return it
799 k = check;
800 class_has_been_loaded = true;
801 }
802 // check if other thread failed to load and cleaned up
803 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
804 }
805 }
806 }
807 }
808 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
809 // case 4: parallelCapable: allow competing threads to try
810 // LOAD_INSTANCE in parallel
811
812 if (!throw_circularity_error && !class_has_been_loaded) {
813 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
814 load_instance_added = true;
815 // For class loaders that do not acquire the classloader object lock,
816 // if they did not catch another thread holding LOAD_INSTANCE,
817 // need a check analogous to the acquire ObjectLocker/find_class
818 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
819 // one final check if the load has already completed
820 // class loaders holding the ObjectLock shouldn't find the class here
821 InstanceKlass* check = find_class(d_hash, name, dictionary);
822 if (check != NULL) {
823 // Klass is already loaded, so return it after checking/adding protection domain
824 k = check;
825 class_has_been_loaded = true;
826 }
827 }
828 }
829
830 // must throw error outside of owning lock
831 if (throw_circularity_error) {
832 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
833 ResourceMark rm(THREAD);
834 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
835 }
836
837 if (!class_has_been_loaded) {
838
839 // Do actual loading
840 k = load_instance_class(name, class_loader, THREAD);
841
842 // If everything was OK (no exceptions, no null return value), and
843 // class_loader is NOT the defining loader, do a little more bookkeeping.
844 if (!HAS_PENDING_EXCEPTION && k != NULL &&
845 k->class_loader() != class_loader()) {
846
847 check_constraints(d_hash, k, class_loader, false, THREAD);
848
849 // Need to check for a PENDING_EXCEPTION again; check_constraints
850 // can throw and doesn't use the CHECK macro.
851 if (!HAS_PENDING_EXCEPTION) {
852 { // Grabbing the Compile_lock prevents systemDictionary updates
853 // during compilations.
854 MutexLocker mu(Compile_lock, THREAD);
855 update_dictionary(d_hash, p_index, p_hash,
856 k, class_loader, THREAD);
857 }
858
859 if (JvmtiExport::should_post_class_load()) {
860 Thread *thread = THREAD;
861 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
862 JvmtiExport::post_class_load((JavaThread *) thread, k);
863 }
864 }
865 }
866 } // load_instance_class
867
868 if (load_instance_added == true) {
869 // clean up placeholder entries for LOAD_INSTANCE success or error
870 // This brackets the SystemDictionary updates for both defining
871 // and initiating loaders
872 MutexLocker mu(SystemDictionary_lock, THREAD);
873 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
874 SystemDictionary_lock->notify_all();
875 }
876 }
877
878 if (HAS_PENDING_EXCEPTION || k == NULL) {
879 return NULL;
880 }
881
882 post_class_load_event(&class_load_start_event, k, loader_data);
883
884 #ifdef ASSERT
885 {
886 ClassLoaderData* loader_data = k->class_loader_data();
887 MutexLocker mu(SystemDictionary_lock, THREAD);
888 Klass* kk = find_class(name, loader_data);
889 assert(kk == k, "should be present in dictionary");
890 }
891 #endif
892
893 // return if the protection domain in NULL
894 if (protection_domain() == NULL) return k;
895
896 // Check the protection domain has the right access
897 if (dictionary->is_valid_protection_domain(d_hash, name,
898 protection_domain)) {
899 return k;
900 }
901
902 // Verify protection domain. If it fails an exception is thrown
903 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
904
905 return k;
906 }
907
908
909 // This routine does not lock the system dictionary.
910 //
911 // Since readers don't hold a lock, we must make sure that system
912 // dictionary entries are only removed at a safepoint (when only one
913 // thread is running), and are added to in a safe way (all links must
914 // be updated in an MT-safe manner).
915 //
916 // Callers should be aware that an entry could be added just after
917 // _dictionary->bucket(index) is read here, so the caller will not see
918 // the new entry.
919
920 Klass* SystemDictionary::find(Symbol* class_name,
921 Handle class_loader,
922 Handle protection_domain,
923 TRAPS) {
924
925 // The result of this call should be consistent with the result
926 // of the call to resolve_instance_class_or_null().
927 // See evaluation 6790209 and 4474172 for more details.
928 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
929 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
930
931 if (loader_data == NULL) {
932 // If the ClassLoaderData has not been setup,
933 // then the class loader has no entries in the dictionary.
934 return NULL;
935 }
936
937 Dictionary* dictionary = loader_data->dictionary();
938 unsigned int d_hash = dictionary->compute_hash(class_name);
939 return dictionary->find(d_hash, class_name,
940 protection_domain);
941 }
942
943
944 // Look for a loaded instance or array klass by name. Do not do any loading.
945 // return NULL in case of error.
946 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
947 Handle class_loader,
948 Handle protection_domain,
949 TRAPS) {
950 Klass* k = NULL;
951 assert(class_name != NULL, "class name must be non NULL");
952
953 if (FieldType::is_array(class_name)) {
954 // The name refers to an array. Parse the name.
955 // dimension and object_key in FieldArrayInfo are assigned as a
956 // side-effect of this call
957 FieldArrayInfo fd;
958 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
959 if (t != T_OBJECT) {
960 k = Universe::typeArrayKlassObj(t);
961 } else {
962 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
963 }
964 if (k != NULL) {
965 k = k->array_klass_or_null(fd.dimension());
966 }
967 } else {
968 k = find(class_name, class_loader, protection_domain, THREAD);
969 }
970 return k;
971 }
972
973 // Note: this method is much like resolve_from_stream, but
974 // does not publish the classes via the SystemDictionary.
975 // Handles unsafe_DefineAnonymousClass and redefineclasses
976 // RedefinedClasses do not add to the class hierarchy
977 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
978 Handle class_loader,
979 Handle protection_domain,
980 ClassFileStream* st,
981 const InstanceKlass* host_klass,
982 GrowableArray<Handle>* cp_patches,
983 TRAPS) {
984
985 EventClassLoad class_load_start_event;
986
987 ClassLoaderData* loader_data;
988 if (host_klass != NULL) {
989 // Create a new CLD for anonymous class, that uses the same class loader
990 // as the host_klass
991 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
992 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
993 } else {
994 loader_data = ClassLoaderData::class_loader_data(class_loader());
995 }
996
997 assert(st != NULL, "invariant");
998 assert(st->need_verify(), "invariant");
999
1000 // Parse stream and create a klass.
1001 // Note that we do this even though this klass might
1002 // already be present in the SystemDictionary, otherwise we would not
1003 // throw potential ClassFormatErrors.
1004
1005 InstanceKlass* k = KlassFactory::create_from_stream(st,
1006 class_name,
1007 loader_data,
1008 protection_domain,
1009 host_klass,
1010 cp_patches,
1011 CHECK_NULL);
1012
1013 if (host_klass != NULL && k != NULL) {
1014 // If it's anonymous, initialize it now, since nobody else will.
1015
1016 {
1017 MutexLocker mu_r(Compile_lock, THREAD);
1018
1019 // Add to class hierarchy, initialize vtables, and do possible
1020 // deoptimizations.
1021 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1022
1023 // But, do not add to dictionary.
1024
1025 // compiled code dependencies need to be validated anyway
1026 notice_modification();
1027 }
1028
1029 // Rewrite and patch constant pool here.
1030 k->link_class(CHECK_NULL);
1031 if (cp_patches != NULL) {
1032 k->constants()->patch_resolved_references(cp_patches);
1033 }
1034 k->eager_initialize(CHECK_NULL);
1035
1036 // notify jvmti
1037 if (JvmtiExport::should_post_class_load()) {
1038 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1039 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1040 }
1041
1042 post_class_load_event(&class_load_start_event, k, loader_data);
1043 }
1044 assert(host_klass != NULL || NULL == cp_patches,
1045 "cp_patches only found with host_klass");
1046
1047 return k;
1048 }
1049
1050 // Add a klass to the system from a stream (called by jni_DefineClass and
1051 // JVM_DefineClass).
1052 // Note: class_name can be NULL. In that case we do not know the name of
1053 // the class until we have parsed the stream.
1054
1055 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1056 Handle class_loader,
1057 Handle protection_domain,
1058 ClassFileStream* st,
1059 TRAPS) {
1060 #if INCLUDE_CDS
1061 ResourceMark rm(THREAD);
1062 if (DumpSharedSpaces && !class_loader.is_null() &&
1063 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1064 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1065 // class, which is used by MethodHandles).
1066 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1067 }
1068 #endif
1069
1070 HandleMark hm(THREAD);
1071
1072 // Classloaders that support parallelism, e.g. bootstrap classloader,
1073 // do not acquire lock here
1074 bool DoObjectLock = true;
1075 if (is_parallelCapable(class_loader)) {
1076 DoObjectLock = false;
1077 }
1078
1079 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1080
1081 // Make sure we are synchronized on the class loader before we proceed
1082 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1083 check_loader_lock_contention(lockObject, THREAD);
1084 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1085
1086 assert(st != NULL, "invariant");
1087
1088 // Parse the stream and create a klass.
1089 // Note that we do this even though this klass might
1090 // already be present in the SystemDictionary, otherwise we would not
1091 // throw potential ClassFormatErrors.
1092 InstanceKlass* k = NULL;
1093
1094 #if INCLUDE_CDS
1095 if (!DumpSharedSpaces) {
1096 k = SystemDictionaryShared::lookup_from_stream(class_name,
1097 class_loader,
1098 protection_domain,
1099 st,
1100 CHECK_NULL);
1101 }
1102 #endif
1103
1104 if (k == NULL) {
1105 if (st->buffer() == NULL) {
1106 return NULL;
1107 }
1108 k = KlassFactory::create_from_stream(st,
1109 class_name,
1110 loader_data,
1111 protection_domain,
1112 NULL, // host_klass
1113 NULL, // cp_patches
1114 CHECK_NULL);
1115 }
1116
1117 assert(k != NULL, "no klass created");
1118 Symbol* h_name = k->name();
1119 assert(class_name == NULL || class_name == h_name, "name mismatch");
1120
1121 // Add class just loaded
1122 // If a class loader supports parallel classloading handle parallel define requests
1123 // find_or_define_instance_class may return a different InstanceKlass
1124 if (is_parallelCapable(class_loader)) {
1125 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1126 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1127 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1128 assert(defined_k != NULL, "Should have a klass if there's no exception");
1129 loader_data->add_to_deallocate_list(k);
1130 k = defined_k;
1131 }
1132 } else {
1133 define_instance_class(k, THREAD);
1134 }
1135
1136 // If defining the class throws an exception register 'k' for cleanup.
1137 if (HAS_PENDING_EXCEPTION) {
1138 assert(k != NULL, "Must have an instance klass here!");
1139 loader_data->add_to_deallocate_list(k);
1140 return NULL;
1141 }
1142
1143 // Make sure we have an entry in the SystemDictionary on success
1144 debug_only( {
1145 MutexLocker mu(SystemDictionary_lock, THREAD);
1146
1147 Klass* check = find_class(h_name, k->class_loader_data());
1148 assert(check == k, "should be present in the dictionary");
1149 } );
1150
1151 return k;
1152 }
1153
1154 #if INCLUDE_CDS
1155 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1156 int number_of_entries) {
1157 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1158 "bad shared dictionary size.");
1159 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1160 _shared_dictionary_size, t, number_of_entries);
1161 }
1162
1163
1164 // If there is a shared dictionary, then find the entry for the
1165 // given shared system class, if any.
1166
1167 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1168 if (shared_dictionary() != NULL) {
1169 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1170 int d_index = shared_dictionary()->hash_to_index(d_hash);
1171
1172 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1173 } else {
1174 return NULL;
1175 }
1176 }
1177
1178
1179 // Load a class from the shared spaces (found through the shared system
1180 // dictionary). Force the superclass and all interfaces to be loaded.
1181 // Update the class definition to include sibling classes and no
1182 // subclasses (yet). [Classes in the shared space are not part of the
1183 // object hierarchy until loaded.]
1184
1185 InstanceKlass* SystemDictionary::load_shared_class(
1186 Symbol* class_name, Handle class_loader, TRAPS) {
1187 InstanceKlass* ik = find_shared_class(class_name);
1188 // Make sure we only return the boot class for the NULL classloader.
1189 if (ik != NULL &&
1190 ik->is_shared_boot_class() && class_loader.is_null()) {
1191 Handle protection_domain;
1192 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1193 }
1194 return NULL;
1195 }
1196
1197 // Check if a shared class can be loaded by the specific classloader:
1198 //
1199 // NULL classloader:
1200 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1201 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1202 // be defined in an unnamed module.
1203 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1204 InstanceKlass* ik,
1205 Handle class_loader, TRAPS) {
1206 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1207 "Cannot use sharing if java.base is patched");
1208 ResourceMark rm;
1209 int path_index = ik->shared_classpath_index();
1210 ClassLoaderData* loader_data = class_loader_data(class_loader);
1211 if (path_index < 0) {
1212 // path_index < 0 indicates that the class is intended for a custom loader
1213 // and should not be loaded by boot/platform/app loaders
1214 if (loader_data->is_builtin_class_loader_data()) {
1215 return false;
1216 } else {
1217 return true;
1218 }
1219 }
1220 SharedClassPathEntry* ent =
1221 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1222 if (!Universe::is_module_initialized()) {
1223 assert(ent != NULL && ent->is_modules_image(),
1224 "Loading non-bootstrap classes before the module system is initialized");
1225 assert(class_loader.is_null(), "sanity");
1226 return true;
1227 }
1228 // Get the pkg_entry from the classloader
1229 TempNewSymbol pkg_name = NULL;
1230 PackageEntry* pkg_entry = NULL;
1231 ModuleEntry* mod_entry = NULL;
1232 const char* pkg_string = NULL;
1233 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1234 if (pkg_name != NULL) {
1235 pkg_string = pkg_name->as_C_string();
1236 if (loader_data != NULL) {
1237 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1238 }
1239 if (pkg_entry != NULL) {
1240 mod_entry = pkg_entry->module();
1241 }
1242 }
1243
1244 // If the archived class is from a module that has been patched at runtime,
1245 // the class cannot be loaded from the archive.
1246 if (mod_entry != NULL && mod_entry->is_patched()) {
1247 return false;
1248 }
1249
1250 if (class_loader.is_null()) {
1251 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1252 // The NULL classloader can load archived class originated from the
1253 // "modules" jimage and the -Xbootclasspath/a. For class from the
1254 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1255 // by the NULL classloader.
1256 if (mod_entry != NULL) {
1257 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1258 // ModuleEntry's location agrees with the archived class' origination.
1259 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1260 return true; // Module class from the "module" jimage
1261 }
1262 }
1263
1264 // If the archived class is not from the "module" jimage, the class can be
1265 // loaded by the NULL classloader if
1266 //
1267 // 1. the class is from the unamed package
1268 // 2. or, the class is not from a module defined in the NULL classloader
1269 // 3. or, the class is from an unamed module
1270 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1271 // the class is from the -Xbootclasspath/a
1272 if (pkg_string == NULL ||
1273 pkg_entry == NULL ||
1274 pkg_entry->in_unnamed_module()) {
1275 assert(mod_entry == NULL ||
1276 mod_entry == loader_data->unnamed_module(),
1277 "the unnamed module is not defined in the classloader");
1278 return true;
1279 }
1280 }
1281 return false;
1282 } else {
1283 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1284 ik, class_loader, pkg_string, pkg_name,
1285 pkg_entry, mod_entry, CHECK_(false));
1286 return res;
1287 }
1288 }
1289
1290 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1291 Handle class_loader,
1292 Handle protection_domain, TRAPS) {
1293
1294 if (ik != NULL) {
1295 Symbol* class_name = ik->name();
1296
1297 bool visible = is_shared_class_visible(
1298 class_name, ik, class_loader, CHECK_NULL);
1299 if (!visible) {
1300 return NULL;
1301 }
1302
1303 // Resolve the superclass and interfaces. They must be the same
1304 // as in dump time, because the layout of <ik> depends on
1305 // the specific layout of ik->super() and ik->local_interfaces().
1306 //
1307 // If unexpected superclass or interfaces are found, we cannot
1308 // load <ik> from the shared archive.
1309
1310 if (ik->super() != NULL) {
1311 Symbol* cn = ik->super()->name();
1312 Klass *s = resolve_super_or_fail(class_name, cn,
1313 class_loader, protection_domain, true, CHECK_NULL);
1314 if (s != ik->super()) {
1315 // The dynamically resolved super class is not the same as the one we used during dump time,
1316 // so we cannot use ik.
1317 return NULL;
1318 } else {
1319 assert(s->is_shared(), "must be");
1320 }
1321 }
1322
1323 Array<Klass*>* interfaces = ik->local_interfaces();
1324 int num_interfaces = interfaces->length();
1325 for (int index = 0; index < num_interfaces; index++) {
1326 Klass* k = interfaces->at(index);
1327 Symbol* name = k->name();
1328 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1329 if (k != i) {
1330 // The dynamically resolved interface class is not the same as the one we used during dump time,
1331 // so we cannot use ik.
1332 return NULL;
1333 } else {
1334 assert(i->is_shared(), "must be");
1335 }
1336 }
1337
1338 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1339 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1340 if (new_ik != NULL) {
1341 // The class is changed by CFLH. Return the new class. The shared class is
1342 // not used.
1343 return new_ik;
1344 }
1345
1346 // Adjust methods to recover missing data. They need addresses for
1347 // interpreter entry points and their default native method address
1348 // must be reset.
1349
1350 // Updating methods must be done under a lock so multiple
1351 // threads don't update these in parallel
1352 //
1353 // Shared classes are all currently loaded by either the bootstrap or
1354 // internal parallel class loaders, so this will never cause a deadlock
1355 // on a custom class loader lock.
1356
1357 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1358 {
1359 HandleMark hm(THREAD);
1360 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1361 check_loader_lock_contention(lockObject, THREAD);
1362 ObjectLocker ol(lockObject, THREAD, true);
1363 // prohibited package check assumes all classes loaded from archive call
1364 // restore_unshareable_info which calls ik->set_package()
1365 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1366 }
1367
1368 ik->print_class_load_logging(loader_data, NULL, NULL);
1369
1370 // For boot loader, ensure that GetSystemPackage knows that a class in this
1371 // package was loaded.
1372 if (class_loader.is_null()) {
1373 int path_index = ik->shared_classpath_index();
1374 ResourceMark rm;
1375 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1376 }
1377
1378 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1379 // Only dump the classes that can be stored into CDS archive
1380 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1381 ResourceMark rm(THREAD);
1382 classlist_file->print_cr("%s", ik->name()->as_C_string());
1383 classlist_file->flush();
1384 }
1385 }
1386
1387 // notify a class loaded from shared object
1388 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1389 }
1390
1391 ik->set_has_passed_fingerprint_check(false);
1392 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1393 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1394 uint64_t cds_fp = ik->get_stored_fingerprint();
1395 if (aot_fp != 0 && aot_fp == cds_fp) {
1396 // This class matches with a class saved in an AOT library
1397 ik->set_has_passed_fingerprint_check(true);
1398 } else {
1399 ResourceMark rm;
1400 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1401 }
1402 }
1403 return ik;
1404 }
1405
1406 void SystemDictionary::clear_invoke_method_table() {
1407 SymbolPropertyEntry* spe = NULL;
1408 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1409 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1410 while (p != NULL) {
1411 spe = p;
1412 p = p->next();
1413 _invoke_method_table->free_entry(spe);
1414 }
1415 }
1416 }
1417 #endif // INCLUDE_CDS
1418
1419 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1420
1421 if (class_loader.is_null()) {
1422 ResourceMark rm;
1423 PackageEntry* pkg_entry = NULL;
1424 bool search_only_bootloader_append = false;
1425 ClassLoaderData *loader_data = class_loader_data(class_loader);
1426
1427 // Find the package in the boot loader's package entry table.
1428 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1429 if (pkg_name != NULL) {
1430 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1431 }
1432
1433 // Prior to attempting to load the class, enforce the boot loader's
1434 // visibility boundaries.
1435 if (!Universe::is_module_initialized()) {
1436 // During bootstrapping, prior to module initialization, any
1437 // class attempting to be loaded must be checked against the
1438 // java.base packages in the boot loader's PackageEntryTable.
1439 // No class outside of java.base is allowed to be loaded during
1440 // this bootstrapping window.
1441 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1442 // Class is either in the unnamed package or in
1443 // a named package within the unnamed module. Either
1444 // case is outside of java.base, do not attempt to
1445 // load the class post java.base definition. If
1446 // java.base has not been defined, let the class load
1447 // and its package will be checked later by
1448 // ModuleEntryTable::verify_javabase_packages.
1449 if (ModuleEntryTable::javabase_defined()) {
1450 return NULL;
1451 }
1452 } else {
1453 // Check that the class' package is defined within java.base.
1454 ModuleEntry* mod_entry = pkg_entry->module();
1455 Symbol* mod_entry_name = mod_entry->name();
1456 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1457 return NULL;
1458 }
1459 }
1460 } else {
1461 // After the module system has been initialized, check if the class'
1462 // package is in a module defined to the boot loader.
1463 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1464 // Class is either in the unnamed package, in a named package
1465 // within a module not defined to the boot loader or in a
1466 // a named package within the unnamed module. In all cases,
1467 // limit visibility to search for the class only in the boot
1468 // loader's append path.
1469 search_only_bootloader_append = true;
1470 }
1471 }
1472
1473 // Prior to bootstrapping's module initialization, never load a class outside
1474 // of the boot loader's module path
1475 assert(Universe::is_module_initialized() ||
1476 !search_only_bootloader_append,
1477 "Attempt to load a class outside of boot loader's module path");
1478
1479 // Search the shared system dictionary for classes preloaded into the
1480 // shared spaces.
1481 InstanceKlass* k = NULL;
1482 {
1483 #if INCLUDE_CDS
1484 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1485 k = load_shared_class(class_name, class_loader, THREAD);
1486 #endif
1487 }
1488
1489 if (k == NULL) {
1490 // Use VM class loader
1491 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1492 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1493 }
1494
1495 // find_or_define_instance_class may return a different InstanceKlass
1496 if (k != NULL) {
1497 InstanceKlass* defined_k =
1498 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1499 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1500 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1501 assert(defined_k != NULL, "Should have a klass if there's no exception");
1502 loader_data->add_to_deallocate_list(k);
1503 k = defined_k;
1504 } else if (HAS_PENDING_EXCEPTION) {
1505 loader_data->add_to_deallocate_list(k);
1506 return NULL;
1507 }
1508 }
1509 return k;
1510 } else {
1511 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1512 ResourceMark rm(THREAD);
1513
1514 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1515 JavaThread* jt = (JavaThread*) THREAD;
1516
1517 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1518 ClassLoader::perf_app_classload_selftime(),
1519 ClassLoader::perf_app_classload_count(),
1520 jt->get_thread_stat()->perf_recursion_counts_addr(),
1521 jt->get_thread_stat()->perf_timers_addr(),
1522 PerfClassTraceTime::CLASS_LOAD);
1523
1524 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1525 // Translate to external class name format, i.e., convert '/' chars to '.'
1526 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1527
1528 JavaValue result(T_OBJECT);
1529
1530 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1531
1532 // Call public unsynchronized loadClass(String) directly for all class loaders.
1533 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1534 // acquire a class-name based lock rather than the class loader object lock.
1535 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1536 JavaCalls::call_virtual(&result,
1537 class_loader,
1538 spec_klass,
1539 vmSymbols::loadClass_name(),
1540 vmSymbols::string_class_signature(),
1541 string,
1542 CHECK_NULL);
1543
1544 assert(result.get_type() == T_OBJECT, "just checking");
1545 oop obj = (oop) result.get_jobject();
1546
1547 // Primitive classes return null since forName() can not be
1548 // used to obtain any of the Class objects representing primitives or void
1549 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1550 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1551 // For user defined Java class loaders, check that the name returned is
1552 // the same as that requested. This check is done for the bootstrap
1553 // loader when parsing the class file.
1554 if (class_name == k->name()) {
1555 return k;
1556 }
1557 }
1558 // Class is not found or has the wrong name, return NULL
1559 return NULL;
1560 }
1561 }
1562
1563 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1564
1565 HandleMark hm(THREAD);
1566 ClassLoaderData* loader_data = k->class_loader_data();
1567 Handle class_loader_h(THREAD, loader_data->class_loader());
1568
1569 // for bootstrap and other parallel classloaders don't acquire lock,
1570 // use placeholder token
1571 // If a parallelCapable class loader calls define_instance_class instead of
1572 // find_or_define_instance_class to get here, we have a timing
1573 // hole with systemDictionary updates and check_constraints
1574 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1575 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1576 compute_loader_lock_object(class_loader_h, THREAD)),
1577 "define called without lock");
1578 }
1579
1580 // Check class-loading constraints. Throw exception if violation is detected.
1581 // Grabs and releases SystemDictionary_lock
1582 // The check_constraints/find_class call and update_dictionary sequence
1583 // must be "atomic" for a specific class/classloader pair so we never
1584 // define two different instanceKlasses for that class/classloader pair.
1585 // Existing classloaders will call define_instance_class with the
1586 // classloader lock held
1587 // Parallel classloaders will call find_or_define_instance_class
1588 // which will require a token to perform the define class
1589 Symbol* name_h = k->name();
1590 Dictionary* dictionary = loader_data->dictionary();
1591 unsigned int d_hash = dictionary->compute_hash(name_h);
1592 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1593
1594 // Register class just loaded with class loader (placed in Vector)
1595 // Note we do this before updating the dictionary, as this can
1596 // fail with an OutOfMemoryError (if it does, we will *not* put this
1597 // class in the dictionary and will not update the class hierarchy).
1598 // JVMTI FollowReferences needs to find the classes this way.
1599 if (k->class_loader() != NULL) {
1600 methodHandle m(THREAD, Universe::loader_addClass_method());
1601 JavaValue result(T_VOID);
1602 JavaCallArguments args(class_loader_h);
1603 args.push_oop(Handle(THREAD, k->java_mirror()));
1604 JavaCalls::call(&result, m, &args, CHECK);
1605 }
1606
1607 // Add the new class. We need recompile lock during update of CHA.
1608 {
1609 unsigned int p_hash = placeholders()->compute_hash(name_h);
1610 int p_index = placeholders()->hash_to_index(p_hash);
1611
1612 MutexLocker mu_r(Compile_lock, THREAD);
1613
1614 // Add to class hierarchy, initialize vtables, and do possible
1615 // deoptimizations.
1616 add_to_hierarchy(k, CHECK); // No exception, but can block
1617
1618 // Add to systemDictionary - so other classes can see it.
1619 // Grabs and releases SystemDictionary_lock
1620 update_dictionary(d_hash, p_index, p_hash,
1621 k, class_loader_h, THREAD);
1622 }
1623 k->eager_initialize(THREAD);
1624
1625 // notify jvmti
1626 if (JvmtiExport::should_post_class_load()) {
1627 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1628 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1629
1630 }
1631 class_define_event(k, loader_data);
1632 }
1633
1634 // Support parallel classloading
1635 // All parallel class loaders, including bootstrap classloader
1636 // lock a placeholder entry for this class/class_loader pair
1637 // to allow parallel defines of different classes for this class loader
1638 // With AllowParallelDefine flag==true, in case they do not synchronize around
1639 // FindLoadedClass/DefineClass, calls, we check for parallel
1640 // loading for them, wait if a defineClass is in progress
1641 // and return the initial requestor's results
1642 // This flag does not apply to the bootstrap classloader.
1643 // With AllowParallelDefine flag==false, call through to define_instance_class
1644 // which will throw LinkageError: duplicate class definition.
1645 // False is the requested default.
1646 // For better performance, the class loaders should synchronize
1647 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1648 // potentially waste time reading and parsing the bytestream.
1649 // Note: VM callers should ensure consistency of k/class_name,class_loader
1650 // Be careful when modifying this code: once you have run
1651 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1652 // you need to find_and_remove it before returning.
1653 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1654 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1655 InstanceKlass* k, TRAPS) {
1656
1657 Symbol* name_h = k->name(); // passed in class_name may be null
1658 ClassLoaderData* loader_data = class_loader_data(class_loader);
1659 Dictionary* dictionary = loader_data->dictionary();
1660
1661 unsigned int d_hash = dictionary->compute_hash(name_h);
1662
1663 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1664 unsigned int p_hash = placeholders()->compute_hash(name_h);
1665 int p_index = placeholders()->hash_to_index(p_hash);
1666 PlaceholderEntry* probe;
1667
1668 {
1669 MutexLocker mu(SystemDictionary_lock, THREAD);
1670 // First check if class already defined
1671 if (is_parallelDefine(class_loader)) {
1672 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1673 if (check != NULL) {
1674 return check;
1675 }
1676 }
1677
1678 // Acquire define token for this class/classloader
1679 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1680 // Wait if another thread defining in parallel
1681 // All threads wait - even those that will throw duplicate class: otherwise
1682 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1683 // if other thread has not finished updating dictionary
1684 while (probe->definer() != NULL) {
1685 SystemDictionary_lock->wait();
1686 }
1687 // Only special cases allow parallel defines and can use other thread's results
1688 // Other cases fall through, and may run into duplicate defines
1689 // caught by finding an entry in the SystemDictionary
1690 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1691 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1692 SystemDictionary_lock->notify_all();
1693 #ifdef ASSERT
1694 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1695 assert(check != NULL, "definer missed recording success");
1696 #endif
1697 return probe->instance_klass();
1698 } else {
1699 // This thread will define the class (even if earlier thread tried and had an error)
1700 probe->set_definer(THREAD);
1701 }
1702 }
1703
1704 define_instance_class(k, THREAD);
1705
1706 Handle linkage_exception = Handle(); // null handle
1707
1708 // definer must notify any waiting threads
1709 {
1710 MutexLocker mu(SystemDictionary_lock, THREAD);
1711 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1712 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1713 if (probe != NULL) {
1714 if (HAS_PENDING_EXCEPTION) {
1715 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1716 CLEAR_PENDING_EXCEPTION;
1717 } else {
1718 probe->set_instance_klass(k);
1719 }
1720 probe->set_definer(NULL);
1721 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1722 SystemDictionary_lock->notify_all();
1723 }
1724 }
1725
1726 // Can't throw exception while holding lock due to rank ordering
1727 if (linkage_exception() != NULL) {
1728 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1729 }
1730
1731 return k;
1732 }
1733
1734 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1735 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1736 if (class_loader.is_null()) {
1737 return Handle(THREAD, _system_loader_lock_obj);
1738 } else {
1739 return class_loader;
1740 }
1741 }
1742
1743 // This method is added to check how often we have to wait to grab loader
1744 // lock. The results are being recorded in the performance counters defined in
1745 // ClassLoader::_sync_systemLoaderLockContentionRate and
1746 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1747 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1748 if (!UsePerfData) {
1749 return;
1750 }
1751
1752 assert(!loader_lock.is_null(), "NULL lock object");
1753
1754 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1755 == ObjectSynchronizer::owner_other) {
1756 // contention will likely happen, so increment the corresponding
1757 // contention counter.
1758 if (loader_lock() == _system_loader_lock_obj) {
1759 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1760 } else {
1761 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1762 }
1763 }
1764 }
1765
1766 // ----------------------------------------------------------------------------
1767 // Lookup
1768
1769 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1770 Symbol* class_name,
1771 Dictionary* dictionary) {
1772 assert_locked_or_safepoint(SystemDictionary_lock);
1773 int index = dictionary->hash_to_index(hash);
1774 return dictionary->find_class(index, hash, class_name);
1775 }
1776
1777
1778 // Basic find on classes in the midst of being loaded
1779 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1780 ClassLoaderData* loader_data) {
1781 assert_locked_or_safepoint(SystemDictionary_lock);
1782 unsigned int p_hash = placeholders()->compute_hash(class_name);
1783 int p_index = placeholders()->hash_to_index(p_hash);
1784 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1785 }
1786
1787
1788 // Used for assertions and verification only
1789 // Precalculating the hash and index is an optimization because there are many lookups
1790 // before adding the class.
1791 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1792 assert_locked_or_safepoint(SystemDictionary_lock);
1793 #ifndef ASSERT
1794 guarantee(VerifyBeforeGC ||
1795 VerifyDuringGC ||
1796 VerifyBeforeExit ||
1797 VerifyDuringStartup ||
1798 VerifyAfterGC, "too expensive");
1799 #endif
1800
1801 Dictionary* dictionary = loader_data->dictionary();
1802 unsigned int d_hash = dictionary->compute_hash(class_name);
1803 return find_class(d_hash, class_name, dictionary);
1804 }
1805
1806
1807 // ----------------------------------------------------------------------------
1808 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1809 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1810 // before a new class is used.
1811
1812 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1813 assert(k != NULL, "just checking");
1814 assert_locked_or_safepoint(Compile_lock);
1815
1816 // Link into hierachy. Make sure the vtables are initialized before linking into
1817 k->append_to_sibling_list(); // add to superklass/sibling list
1818 k->process_interfaces(THREAD); // handle all "implements" declarations
1819 k->set_init_state(InstanceKlass::loaded);
1820 // Now flush all code that depended on old class hierarchy.
1821 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1822 // Also, first reinitialize vtable because it may have gotten out of synch
1823 // while the new class wasn't connected to the class hierarchy.
1824 CodeCache::flush_dependents_on(k);
1825 }
1826
1827 // ----------------------------------------------------------------------------
1828 // GC support
1829
1830 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1831 roots_oops_do(blk, NULL);
1832 }
1833
1834
1835 #ifdef ASSERT
1836 class VerifySDReachableAndLiveClosure : public OopClosure {
1837 private:
1838 BoolObjectClosure* _is_alive;
1839
1840 template <class T> void do_oop_work(T* p) {
1841 oop obj = oopDesc::load_decode_heap_oop(p);
1842 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1843 }
1844
1845 public:
1846 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1847
1848 virtual void do_oop(oop* p) { do_oop_work(p); }
1849 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1850 };
1851 #endif
1852
1853 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1854 // Note: anonymous classes are not in the SD.
1855 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1856 GCTimer* gc_timer,
1857 bool do_cleaning) {
1858
1859
1860 bool unloading_occurred;
1861 {
1862 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1863
1864 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1865 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1866 do_cleaning);
1867 }
1868
1869 if (unloading_occurred) {
1870 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1871 constraints()->purge_loader_constraints();
1872 resolution_errors()->purge_resolution_errors();
1873 }
1874
1875 {
1876 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1877 // Oops referenced by the protection domain cache table may get unreachable independently
1878 // of the class loader (eg. cached protection domain oops). So we need to
1879 // explicitly unlink them here.
1880 _pd_cache_table->unlink(is_alive);
1881
1882 #ifdef ASSERT
1883 VerifySDReachableAndLiveClosure cl(is_alive);
1884 _pd_cache_table->oops_do(&cl);
1885 #endif
1886 }
1887
1888 if (do_cleaning) {
1889 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1890 ResolvedMethodTable::unlink(is_alive);
1891 }
1892
1893 return unloading_occurred;
1894 }
1895
1896 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1897 strong->do_oop(&_java_system_loader);
1898 strong->do_oop(&_java_platform_loader);
1899 strong->do_oop(&_system_loader_lock_obj);
1900 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1901
1902 // Do strong roots marking if the closures are the same.
1903 if (strong == weak || !ClassUnloading) {
1904 // Only the protection domain oops contain references into the heap. Iterate
1905 // over all of them.
1906 _pd_cache_table->oops_do(strong);
1907 } else {
1908 if (weak != NULL) {
1909 _pd_cache_table->oops_do(weak);
1910 }
1911 }
1912
1913 // Visit extra methods
1914 invoke_method_table()->oops_do(strong);
1915
1916 if (weak != NULL) {
1917 ResolvedMethodTable::oops_do(weak);
1918 }
1919 }
1920
1921 void SystemDictionary::oops_do(OopClosure* f) {
1922 f->do_oop(&_java_system_loader);
1923 f->do_oop(&_java_platform_loader);
1924 f->do_oop(&_system_loader_lock_obj);
1925 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1926
1927 // Only the protection domain oops contain references into the heap. Iterate
1928 // over all of them.
1929 _pd_cache_table->oops_do(f);
1930
1931 // Visit extra methods
1932 invoke_method_table()->oops_do(f);
1933
1934 ResolvedMethodTable::oops_do(f);
1935 }
1936
1937 // CDS: scan and relocate all classes in the system dictionary.
1938 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1939 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1940 }
1941
1942 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1943 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1944 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1945 it->push(well_known_klass_addr((WKID)id));
1946 }
1947 }
1948
1949 void SystemDictionary::methods_do(void f(Method*)) {
1950 // Walk methods in loaded classes
1951 ClassLoaderDataGraph::methods_do(f);
1952 // Walk method handle intrinsics
1953 invoke_method_table()->methods_do(f);
1954 }
1955
1956 class RemoveClassesClosure : public CLDClosure {
1957 public:
1958 void do_cld(ClassLoaderData* cld) {
1959 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1960 cld->dictionary()->remove_classes_in_error_state();
1961 }
1962 }
1963 };
1964
1965 void SystemDictionary::remove_classes_in_error_state() {
1966 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1967 RemoveClassesClosure rcc;
1968 ClassLoaderDataGraph::cld_do(&rcc);
1969 }
1970
1971 // ----------------------------------------------------------------------------
1972 // Lazily load klasses
1973
1974 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1975 // if multiple threads calling this function, only one thread will load
1976 // the class. The other threads will find the loaded version once the
1977 // class is loaded.
1978 Klass* aos = _abstract_ownable_synchronizer_klass;
1979 if (aos == NULL) {
1980 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1981 // Force a fence to prevent any read before the write completes
1982 OrderAccess::fence();
1983 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1984 }
1985 }
1986
1987 // ----------------------------------------------------------------------------
1988 // Initialization
1989
1990 void SystemDictionary::initialize(TRAPS) {
1991 // Allocate arrays
1992 _placeholders = new PlaceholderTable(_placeholder_table_size);
1993 _number_of_modifications = 0;
1994 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1995 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1996 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1997 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1998
1999 // Allocate private object used as system class loader lock
2000 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2001 // Initialize basic classes
2002 initialize_preloaded_classes(CHECK);
2003 }
2004
2005 // Compact table of directions on the initialization of klasses:
2006 static const short wk_init_info[] = {
2007 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2008 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2009 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2010 | (int)SystemDictionary::option ),
2011 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2012 #undef WK_KLASS_INIT_INFO
2013 0
2014 };
2015
2016 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2017 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2018 int info = wk_init_info[id - FIRST_WKID];
2019 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2020 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2021 InstanceKlass** klassp = &_well_known_klasses[id];
2022
2023 bool must_load;
2024 #if INCLUDE_JVMCI
2025 if (EnableJVMCI) {
2026 // If JVMCI is enabled we require its classes to be found.
2027 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2028 } else
2029 #endif
2030 {
2031 must_load = (init_opt < SystemDictionary::Opt);
2032 }
2033
2034 if ((*klassp) == NULL) {
2035 Klass* k;
2036 if (must_load) {
2037 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2038 } else {
2039 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2040 }
2041 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2042 }
2043 return ((*klassp) != NULL);
2044 }
2045
2046 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2047 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2048 for (int id = (int)start_id; id < (int)limit_id; id++) {
2049 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2050 int info = wk_init_info[id - FIRST_WKID];
2051 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2052 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2053
2054 initialize_wk_klass((WKID)id, opt, CHECK);
2055 }
2056
2057 // move the starting value forward to the limit:
2058 start_id = limit_id;
2059 }
2060
2061 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2062 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2063
2064 // Create the ModuleEntry for java.base. This call needs to be done here,
2065 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2066 ClassLoader::classLoader_init2(CHECK);
2067
2068 // Preload commonly used klasses
2069 WKID scan = FIRST_WKID;
2070 // first do Object, then String, Class
2071 #if INCLUDE_CDS
2072 if (UseSharedSpaces) {
2073 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2074 // Initialize the constant pool for the Object_class
2075 Object_klass()->constants()->restore_unshareable_info(CHECK);
2076 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2077 } else
2078 #endif
2079 {
2080 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2081 }
2082
2083 // Calculate offsets for String and Class classes since they are loaded and
2084 // can be used after this point.
2085 java_lang_String::compute_offsets();
2086 java_lang_Class::compute_offsets();
2087
2088 // Fixup mirrors for classes loaded before java.lang.Class.
2089 // These calls iterate over the objects currently in the perm gen
2090 // so calling them at this point is matters (not before when there
2091 // are fewer objects and not later after there are more objects
2092 // in the perm gen.
2093 Universe::initialize_basic_type_mirrors(CHECK);
2094 Universe::fixup_mirrors(CHECK);
2095
2096 // do a bunch more:
2097 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2098
2099 // Preload ref klasses and set reference types
2100 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2101 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2102
2103 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2104 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2105 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2106 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2107 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2108
2109 // JSR 292 classes
2110 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2111 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2112 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2113 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2114 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2115
2116 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2117 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2118 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2119 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2120 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2121 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2122 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2123 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2124 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2125 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2126
2127 { // Compute whether we should use checkPackageAccess or NOT
2128 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2129 _has_checkPackageAccess = (method != NULL);
2130 }
2131 }
2132
2133 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2134 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2135 BasicType SystemDictionary::box_klass_type(Klass* k) {
2136 assert(k != NULL, "");
2137 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2138 if (_box_klasses[i] == k)
2139 return (BasicType)i;
2140 }
2141 return T_OBJECT;
2142 }
2143
2144 // Constraints on class loaders. The details of the algorithm can be
2145 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2146 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2147 // that the dictionary needs to maintain a set of contraints that
2148 // must be satisfied by all classes in the dictionary.
2149 // if defining is true, then LinkageError if already in dictionary
2150 // if initiating loader, then ok if InstanceKlass matches existing entry
2151
2152 void SystemDictionary::check_constraints(unsigned int d_hash,
2153 InstanceKlass* k,
2154 Handle class_loader, bool defining,
2155 TRAPS) {
2156 const char *linkage_error1 = NULL;
2157 const char *linkage_error2 = NULL;
2158 {
2159 Symbol* name = k->name();
2160 ClassLoaderData *loader_data = class_loader_data(class_loader);
2161
2162 MutexLocker mu(SystemDictionary_lock, THREAD);
2163
2164 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2165 if (check != NULL) {
2166 // if different InstanceKlass - duplicate class definition,
2167 // else - ok, class loaded by a different thread in parallel,
2168 // we should only have found it if it was done loading and ok to use
2169 // dictionary only holds instance classes, placeholders
2170 // also holds array classes
2171
2172 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2173 if ((defining == true) || (k != check)) {
2174 linkage_error1 = "loader (instance of ";
2175 linkage_error2 = "): attempted duplicate class definition for name: \"";
2176 } else {
2177 return;
2178 }
2179 }
2180
2181 #ifdef ASSERT
2182 Symbol* ph_check = find_placeholder(name, loader_data);
2183 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2184 #endif
2185
2186 if (linkage_error1 == NULL) {
2187 if (constraints()->check_or_update(k, class_loader, name) == false) {
2188 linkage_error1 = "loader constraint violation: loader (instance of ";
2189 linkage_error2 = ") previously initiated loading for a different type with name \"";
2190 }
2191 }
2192 }
2193
2194 // Throw error now if needed (cannot throw while holding
2195 // SystemDictionary_lock because of rank ordering)
2196
2197 if (linkage_error1) {
2198 ResourceMark rm(THREAD);
2199 const char* class_loader_name = loader_name(class_loader());
2200 char* type_name = k->name()->as_C_string();
2201 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2202 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2203 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2204 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2205 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2206 }
2207 }
2208
2209
2210 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2211 // have been called.
2212 void SystemDictionary::update_dictionary(unsigned int d_hash,
2213 int p_index, unsigned int p_hash,
2214 InstanceKlass* k,
2215 Handle class_loader,
2216 TRAPS) {
2217 // Compile_lock prevents systemDictionary updates during compilations
2218 assert_locked_or_safepoint(Compile_lock);
2219 Symbol* name = k->name();
2220 ClassLoaderData *loader_data = class_loader_data(class_loader);
2221
2222 {
2223 MutexLocker mu1(SystemDictionary_lock, THREAD);
2224
2225 // See whether biased locking is enabled and if so set it for this
2226 // klass.
2227 // Note that this must be done past the last potential blocking
2228 // point / safepoint. We enable biased locking lazily using a
2229 // VM_Operation to iterate the SystemDictionary and installing the
2230 // biasable mark word into each InstanceKlass's prototype header.
2231 // To avoid race conditions where we accidentally miss enabling the
2232 // optimization for one class in the process of being added to the
2233 // dictionary, we must not safepoint after the test of
2234 // BiasedLocking::enabled().
2235 if (UseBiasedLocking && BiasedLocking::enabled()) {
2236 // Set biased locking bit for all loaded classes; it will be
2237 // cleared if revocation occurs too often for this type
2238 // NOTE that we must only do this when the class is initally
2239 // defined, not each time it is referenced from a new class loader
2240 if (k->class_loader() == class_loader()) {
2241 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2242 }
2243 }
2244
2245 // Make a new dictionary entry.
2246 Dictionary* dictionary = loader_data->dictionary();
2247 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2248 if (sd_check == NULL) {
2249 dictionary->add_klass(d_hash, name, k);
2250 notice_modification();
2251 }
2252 #ifdef ASSERT
2253 sd_check = find_class(d_hash, name, dictionary);
2254 assert (sd_check != NULL, "should have entry in dictionary");
2255 // Note: there may be a placeholder entry: for circularity testing
2256 // or for parallel defines
2257 #endif
2258 SystemDictionary_lock->notify_all();
2259 }
2260 }
2261
2262
2263 // Try to find a class name using the loader constraints. The
2264 // loader constraints might know about a class that isn't fully loaded
2265 // yet and these will be ignored.
2266 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2267 Symbol* class_name, Handle class_loader, TRAPS) {
2268
2269 // First see if it has been loaded directly.
2270 // Force the protection domain to be null. (This removes protection checks.)
2271 Handle no_protection_domain;
2272 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2273 no_protection_domain, CHECK_NULL);
2274 if (klass != NULL)
2275 return klass;
2276
2277 // Now look to see if it has been loaded elsewhere, and is subject to
2278 // a loader constraint that would require this loader to return the
2279 // klass that is already loaded.
2280 if (FieldType::is_array(class_name)) {
2281 // For array classes, their Klass*s are not kept in the
2282 // constraint table. The element Klass*s are.
2283 FieldArrayInfo fd;
2284 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2285 if (t != T_OBJECT) {
2286 klass = Universe::typeArrayKlassObj(t);
2287 } else {
2288 MutexLocker mu(SystemDictionary_lock, THREAD);
2289 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2290 }
2291 // If element class already loaded, allocate array klass
2292 if (klass != NULL) {
2293 klass = klass->array_klass_or_null(fd.dimension());
2294 }
2295 } else {
2296 MutexLocker mu(SystemDictionary_lock, THREAD);
2297 // Non-array classes are easy: simply check the constraint table.
2298 klass = constraints()->find_constrained_klass(class_name, class_loader);
2299 }
2300
2301 return klass;
2302 }
2303
2304
2305 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2306 Handle class_loader1,
2307 Handle class_loader2,
2308 Thread* THREAD) {
2309 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2310 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2311
2312 Symbol* constraint_name = NULL;
2313 if (!FieldType::is_array(class_name)) {
2314 constraint_name = class_name;
2315 } else {
2316 // For array classes, their Klass*s are not kept in the
2317 // constraint table. The element classes are.
2318 FieldArrayInfo fd;
2319 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2320 // primitive types always pass
2321 if (t != T_OBJECT) {
2322 return true;
2323 } else {
2324 constraint_name = fd.object_key();
2325 }
2326 }
2327
2328 Dictionary* dictionary1 = loader_data1->dictionary();
2329 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2330
2331 Dictionary* dictionary2 = loader_data2->dictionary();
2332 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2333
2334 {
2335 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2336 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2337 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2338 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2339 klass2, class_loader2);
2340 }
2341 }
2342
2343 // Add entry to resolution error table to record the error when the first
2344 // attempt to resolve a reference to a class has failed.
2345 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2346 Symbol* error, Symbol* message) {
2347 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2348 int index = resolution_errors()->hash_to_index(hash);
2349 {
2350 MutexLocker ml(SystemDictionary_lock, Thread::current());
2351 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2352 }
2353 }
2354
2355 // Delete a resolution error for RedefineClasses for a constant pool is going away
2356 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2357 resolution_errors()->delete_entry(pool);
2358 }
2359
2360 // Lookup resolution error table. Returns error if found, otherwise NULL.
2361 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2362 Symbol** message) {
2363 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2364 int index = resolution_errors()->hash_to_index(hash);
2365 {
2366 MutexLocker ml(SystemDictionary_lock, Thread::current());
2367 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2368 if (entry != NULL) {
2369 *message = entry->message();
2370 return entry->error();
2371 } else {
2372 return NULL;
2373 }
2374 }
2375 }
2376
2377
2378 // Signature constraints ensure that callers and callees agree about
2379 // the meaning of type names in their signatures. This routine is the
2380 // intake for constraints. It collects them from several places:
2381 //
2382 // * LinkResolver::resolve_method (if check_access is true) requires
2383 // that the resolving class (the caller) and the defining class of
2384 // the resolved method (the callee) agree on each type in the
2385 // method's signature.
2386 //
2387 // * LinkResolver::resolve_interface_method performs exactly the same
2388 // checks.
2389 //
2390 // * LinkResolver::resolve_field requires that the constant pool
2391 // attempting to link to a field agree with the field's defining
2392 // class about the type of the field signature.
2393 //
2394 // * klassVtable::initialize_vtable requires that, when a class
2395 // overrides a vtable entry allocated by a superclass, that the
2396 // overriding method (i.e., the callee) agree with the superclass
2397 // on each type in the method's signature.
2398 //
2399 // * klassItable::initialize_itable requires that, when a class fills
2400 // in its itables, for each non-abstract method installed in an
2401 // itable, the method (i.e., the callee) agree with the interface
2402 // on each type in the method's signature.
2403 //
2404 // All those methods have a boolean (check_access, checkconstraints)
2405 // which turns off the checks. This is used from specialized contexts
2406 // such as bootstrapping, dumping, and debugging.
2407 //
2408 // No direct constraint is placed between the class and its
2409 // supertypes. Constraints are only placed along linked relations
2410 // between callers and callees. When a method overrides or implements
2411 // an abstract method in a supertype (superclass or interface), the
2412 // constraints are placed as if the supertype were the caller to the
2413 // overriding method. (This works well, since callers to the
2414 // supertype have already established agreement between themselves and
2415 // the supertype.) As a result of all this, a class can disagree with
2416 // its supertype about the meaning of a type name, as long as that
2417 // class neither calls a relevant method of the supertype, nor is
2418 // called (perhaps via an override) from the supertype.
2419 //
2420 //
2421 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2422 //
2423 // Make sure all class components (including arrays) in the given
2424 // signature will be resolved to the same class in both loaders.
2425 // Returns the name of the type that failed a loader constraint check, or
2426 // NULL if no constraint failed. No exception except OOME is thrown.
2427 // Arrays are not added to the loader constraint table, their elements are.
2428 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2429 Handle loader1, Handle loader2,
2430 bool is_method, TRAPS) {
2431 // Nothing to do if loaders are the same.
2432 if (loader1() == loader2()) {
2433 return NULL;
2434 }
2435
2436 SignatureStream sig_strm(signature, is_method);
2437 while (!sig_strm.is_done()) {
2438 if (sig_strm.is_object()) {
2439 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2440 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2441 return sig;
2442 }
2443 }
2444 sig_strm.next();
2445 }
2446 return NULL;
2447 }
2448
2449
2450 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2451 Symbol* signature,
2452 TRAPS) {
2453 methodHandle empty;
2454 assert(MethodHandles::is_signature_polymorphic(iid) &&
2455 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2456 iid != vmIntrinsics::_invokeGeneric,
2457 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2458
2459 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2460 int index = invoke_method_table()->hash_to_index(hash);
2461 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2462 methodHandle m;
2463 if (spe == NULL || spe->method() == NULL) {
2464 spe = NULL;
2465 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2466 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2467 if (!Arguments::is_interpreter_only()) {
2468 // Generate a compiled form of the MH intrinsic.
2469 AdapterHandlerLibrary::create_native_wrapper(m);
2470 // Check if have the compiled code.
2471 if (!m->has_compiled_code()) {
2472 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2473 "Out of space in CodeCache for method handle intrinsic", empty);
2474 }
2475 }
2476 // Now grab the lock. We might have to throw away the new method,
2477 // if a racing thread has managed to install one at the same time.
2478 {
2479 MutexLocker ml(SystemDictionary_lock, THREAD);
2480 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2481 if (spe == NULL)
2482 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2483 if (spe->method() == NULL)
2484 spe->set_method(m());
2485 }
2486 }
2487
2488 assert(spe != NULL && spe->method() != NULL, "");
2489 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2490 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2491 "MH intrinsic invariant");
2492 return spe->method();
2493 }
2494
2495 // Helper for unpacking the return value from linkMethod and linkCallSite.
2496 static methodHandle unpack_method_and_appendix(Handle mname,
2497 Klass* accessing_klass,
2498 objArrayHandle appendix_box,
2499 Handle* appendix_result,
2500 TRAPS) {
2501 methodHandle empty;
2502 if (mname.not_null()) {
2503 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2504 if (m != NULL) {
2505 oop appendix = appendix_box->obj_at(0);
2506 if (TraceMethodHandles) {
2507 #ifndef PRODUCT
2508 ttyLocker ttyl;
2509 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2510 m->print();
2511 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2512 tty->cr();
2513 #endif //PRODUCT
2514 }
2515 (*appendix_result) = Handle(THREAD, appendix);
2516 // the target is stored in the cpCache and if a reference to this
2517 // MethodName is dropped we need a way to make sure the
2518 // class_loader containing this method is kept alive.
2519 // FIXME: the appendix might also preserve this dependency.
2520 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2521 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2522 return methodHandle(THREAD, m);
2523 }
2524 }
2525 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2526 return empty;
2527 }
2528
2529 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2530 Symbol* name,
2531 Symbol* signature,
2532 Klass* accessing_klass,
2533 Handle *appendix_result,
2534 Handle *method_type_result,
2535 TRAPS) {
2536 methodHandle empty;
2537 assert(THREAD->can_call_java() ,"");
2538 Handle method_type =
2539 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2540
2541 int ref_kind = JVM_REF_invokeVirtual;
2542 oop name_oop = StringTable::intern(name, CHECK_(empty));
2543 Handle name_str (THREAD, name_oop);
2544 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2545 assert(appendix_box->obj_at(0) == NULL, "");
2546
2547 // This should not happen. JDK code should take care of that.
2548 if (accessing_klass == NULL || method_type.is_null()) {
2549 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2550 }
2551
2552 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2553 JavaCallArguments args;
2554 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2555 args.push_int(ref_kind);
2556 args.push_oop(Handle(THREAD, klass->java_mirror()));
2557 args.push_oop(name_str);
2558 args.push_oop(method_type);
2559 args.push_oop(appendix_box);
2560 JavaValue result(T_OBJECT);
2561 JavaCalls::call_static(&result,
2562 SystemDictionary::MethodHandleNatives_klass(),
2563 vmSymbols::linkMethod_name(),
2564 vmSymbols::linkMethod_signature(),
2565 &args, CHECK_(empty));
2566 Handle mname(THREAD, (oop) result.get_jobject());
2567 (*method_type_result) = method_type;
2568 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2569 }
2570
2571 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2572 // We must ensure that all class loaders everywhere will reach this class, for any client.
2573 // This is a safe bet for public classes in java.lang, such as Object and String.
2574 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2575 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2576 static bool is_always_visible_class(oop mirror) {
2577 Klass* klass = java_lang_Class::as_Klass(mirror);
2578 if (klass->is_objArray_klass()) {
2579 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2580 }
2581 if (klass->is_typeArray_klass()) {
2582 return true; // primitive array
2583 }
2584 assert(klass->is_instance_klass(), "%s", klass->external_name());
2585 return klass->is_public() &&
2586 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2587 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2588 }
2589
2590
2591 // Return the Java mirror (java.lang.Class instance) for a single-character
2592 // descriptor. This result, when available, is the same as produced by the
2593 // heavier API point of the same name that takes a Symbol.
2594 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2595 return java_lang_Class::primitive_mirror(char2type(signature_char));
2596 }
2597
2598 // Find or construct the Java mirror (java.lang.Class instance) for a
2599 // for the given field type signature, as interpreted relative to the
2600 // given class loader. Handles primitives, void, references, arrays,
2601 // and all other reflectable types, except method types.
2602 // N.B. Code in reflection should use this entry point.
2603 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2604 Klass* accessing_klass,
2605 Handle class_loader,
2606 Handle protection_domain,
2607 SignatureStream::FailureMode failure_mode,
2608 TRAPS) {
2609 Handle empty;
2610
2611 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2612 "one or the other, or perhaps neither");
2613
2614 Symbol* type = signature;
2615
2616 // What we have here must be a valid field descriptor,
2617 // and all valid field descriptors are supported.
2618 // Produce the same java.lang.Class that reflection reports.
2619 if (type->utf8_length() == 1) {
2620
2621 // It's a primitive. (Void has a primitive mirror too.)
2622 char ch = (char) type->byte_at(0);
2623 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2624 return Handle(THREAD, find_java_mirror_for_type(ch));
2625
2626 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2627
2628 // It's a reference type.
2629 if (accessing_klass != NULL) {
2630 class_loader = Handle(THREAD, accessing_klass->class_loader());
2631 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2632 }
2633 Klass* constant_type_klass;
2634 if (failure_mode == SignatureStream::ReturnNull) {
2635 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2636 CHECK_(empty));
2637 } else {
2638 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2639 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2640 throw_error, CHECK_(empty));
2641 }
2642 if (constant_type_klass == NULL) {
2643 return Handle(); // report failure this way
2644 }
2645 Handle mirror(THREAD, constant_type_klass->java_mirror());
2646
2647 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2648 if (accessing_klass != NULL) {
2649 Klass* sel_klass = constant_type_klass;
2650 bool fold_type_to_class = true;
2651 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2652 fold_type_to_class, CHECK_(empty));
2653 }
2654
2655 return mirror;
2656
2657 }
2658
2659 // Fall through to an error.
2660 assert(false, "unsupported mirror syntax");
2661 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2662 }
2663
2664
2665 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2666 // signature, as interpreted relative to the given class loader.
2667 // Because of class loader constraints, all method handle usage must be
2668 // consistent with this loader.
2669 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2670 Klass* accessing_klass,
2671 TRAPS) {
2672 Handle empty;
2673 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2674 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2675 int index = invoke_method_table()->hash_to_index(hash);
2676 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2677 if (spe != NULL && spe->method_type() != NULL) {
2678 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2679 return Handle(THREAD, spe->method_type());
2680 } else if (!THREAD->can_call_java()) {
2681 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2682 return Handle(); // do not attempt from within compiler, unless it was cached
2683 }
2684
2685 Handle class_loader, protection_domain;
2686 if (accessing_klass != NULL) {
2687 class_loader = Handle(THREAD, accessing_klass->class_loader());
2688 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2689 }
2690 bool can_be_cached = true;
2691 int npts = ArgumentCount(signature).size();
2692 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2693 int arg = 0;
2694 Handle rt; // the return type from the signature
2695 ResourceMark rm(THREAD);
2696 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2697 oop mirror = NULL;
2698 if (can_be_cached) {
2699 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2700 mirror = ss.as_java_mirror(Handle(), Handle(),
2701 SignatureStream::ReturnNull, CHECK_(empty));
2702 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2703 // Fall back to accessing_klass context.
2704 can_be_cached = false;
2705 }
2706 }
2707 if (!can_be_cached) {
2708 // Resolve, throwing a real error if it doesn't work.
2709 mirror = ss.as_java_mirror(class_loader, protection_domain,
2710 SignatureStream::NCDFError, CHECK_(empty));
2711 }
2712 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2713 if (ss.at_return_type())
2714 rt = Handle(THREAD, mirror);
2715 else
2716 pts->obj_at_put(arg++, mirror);
2717
2718 // Check accessibility.
2719 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2720 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2721 mirror = NULL; // safety
2722 // Emulate ConstantPool::verify_constant_pool_resolve.
2723 bool fold_type_to_class = true;
2724 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2725 fold_type_to_class, CHECK_(empty));
2726 }
2727 }
2728 assert(arg == npts, "");
2729
2730 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2731 JavaCallArguments args(Handle(THREAD, rt()));
2732 args.push_oop(pts);
2733 JavaValue result(T_OBJECT);
2734 JavaCalls::call_static(&result,
2735 SystemDictionary::MethodHandleNatives_klass(),
2736 vmSymbols::findMethodHandleType_name(),
2737 vmSymbols::findMethodHandleType_signature(),
2738 &args, CHECK_(empty));
2739 Handle method_type(THREAD, (oop) result.get_jobject());
2740
2741 if (can_be_cached) {
2742 // We can cache this MethodType inside the JVM.
2743 MutexLocker ml(SystemDictionary_lock, THREAD);
2744 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2745 if (spe == NULL)
2746 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2747 if (spe->method_type() == NULL) {
2748 spe->set_method_type(method_type());
2749 }
2750 }
2751
2752 // report back to the caller with the MethodType
2753 return method_type;
2754 }
2755
2756 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2757 Klass* accessing_klass,
2758 TRAPS) {
2759 Handle empty;
2760 ResourceMark rm(THREAD);
2761 SignatureStream ss(signature, /*is_method=*/ false);
2762 if (!ss.is_done()) {
2763 Handle class_loader, protection_domain;
2764 if (accessing_klass != NULL) {
2765 class_loader = Handle(THREAD, accessing_klass->class_loader());
2766 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2767 }
2768 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2769 ss.next();
2770 if (ss.is_done()) {
2771 return Handle(THREAD, mirror);
2772 }
2773 }
2774 return empty;
2775 }
2776
2777 // Ask Java code to find or construct a method handle constant.
2778 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2779 int ref_kind, //e.g., JVM_REF_invokeVirtual
2780 Klass* callee,
2781 Symbol* name,
2782 Symbol* signature,
2783 TRAPS) {
2784 Handle empty;
2785 if (caller == NULL) {
2786 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2787 }
2788 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2789 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2790
2791 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2792 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2793 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2794 java_lang_invoke_MemberName::set_name (mname(), name_str());
2795 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2796 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2797
2798 if (ref_kind == JVM_REF_invokeVirtual &&
2799 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2800 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2801 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2802 // They are public signature polymorphic methods, but require appendix argument
2803 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2804 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2805 } else {
2806 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2807 }
2808
2809 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2810 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2811
2812 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2813 JavaCallArguments args;
2814 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2815 args.push_int(ref_kind);
2816 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2817 args.push_oop(name_str);
2818 args.push_oop(type);
2819 JavaValue result(T_OBJECT);
2820 JavaCalls::call_static(&result,
2821 SystemDictionary::MethodHandleNatives_klass(),
2822 vmSymbols::linkMethodHandleConstant_name(),
2823 vmSymbols::linkMethodHandleConstant_signature(),
2824 &args, CHECK_(empty));
2825 return Handle(THREAD, (oop) result.get_jobject());
2826 }
2827
2828 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2829 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2830 int condy_index,
2831 Handle bootstrap_specifier,
2832 Symbol* name,
2833 Symbol* type,
2834 TRAPS) {
2835 Handle empty;
2836 Handle bsm, info;
2837 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2838 bsm = bootstrap_specifier;
2839 } else {
2840 assert(bootstrap_specifier->is_objArray(), "");
2841 objArrayOop args = (objArrayOop) bootstrap_specifier();
2842 assert(args->length() == 2, "");
2843 bsm = Handle(THREAD, args->obj_at(0));
2844 info = Handle(THREAD, args->obj_at(1));
2845 }
2846 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2847 "caller must supply a valid BSM");
2848
2849 // This should not happen. JDK code should take care of that.
2850 if (caller == NULL) {
2851 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2852 }
2853
2854 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2855
2856 // Resolve the constant type in the context of the caller class
2857 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2858 CHECK_(empty));
2859
2860 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2861 JavaCallArguments args;
2862 args.push_oop(Handle(THREAD, caller->java_mirror()));
2863 args.push_int(condy_index);
2864 args.push_oop(bsm);
2865 args.push_oop(constant_name);
2866 args.push_oop(type_mirror);
2867 args.push_oop(info);
2868 JavaValue result(T_OBJECT);
2869 JavaCalls::call_static(&result,
2870 SystemDictionary::MethodHandleNatives_klass(),
2871 vmSymbols::linkDynamicConstant_name(),
2872 vmSymbols::linkDynamicConstant_signature(),
2873 &args, CHECK_(empty));
2874
2875 return Handle(THREAD, (oop) result.get_jobject());
2876 }
2877
2878 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2879 // name and signature, as interpreted relative to the given class loader.
2880 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2881 int indy_index,
2882 Handle bootstrap_specifier,
2883 Symbol* name,
2884 Symbol* type,
2885 Handle *appendix_result,
2886 Handle *method_type_result,
2887 TRAPS) {
2888 methodHandle empty;
2889 Handle bsm, info;
2890 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2891 bsm = bootstrap_specifier;
2892 } else {
2893 objArrayOop args = (objArrayOop) bootstrap_specifier();
2894 assert(args->length() == 2, "");
2895 bsm = Handle(THREAD, args->obj_at(0));
2896 info = Handle(THREAD, args->obj_at(1));
2897 }
2898 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2899 "caller must supply a valid BSM");
2900
2901 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2902 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2903
2904 // This should not happen. JDK code should take care of that.
2905 if (caller == NULL || method_type.is_null()) {
2906 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2907 }
2908
2909 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2910 assert(appendix_box->obj_at(0) == NULL, "");
2911
2912 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2913 JavaCallArguments args;
2914 args.push_oop(Handle(THREAD, caller->java_mirror()));
2915 args.push_int(indy_index);
2916 args.push_oop(bsm);
2917 args.push_oop(method_name);
2918 args.push_oop(method_type);
2919 args.push_oop(info);
2920 args.push_oop(appendix_box);
2921 JavaValue result(T_OBJECT);
2922 JavaCalls::call_static(&result,
2923 SystemDictionary::MethodHandleNatives_klass(),
2924 vmSymbols::linkCallSite_name(),
2925 vmSymbols::linkCallSite_signature(),
2926 &args, CHECK_(empty));
2927 Handle mname(THREAD, (oop) result.get_jobject());
2928 (*method_type_result) = method_type;
2929 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2930 }
2931
2932 // Protection domain cache table handling
2933
2934 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2935 return _pd_cache_table->get(protection_domain);
2936 }
2937
2938 #if INCLUDE_CDS
2939 void SystemDictionary::reorder_dictionary_for_sharing() {
2940 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2941 }
2942 #endif
2943
2944 size_t SystemDictionary::count_bytes_for_buckets() {
2945 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2946 }
2947
2948 size_t SystemDictionary::count_bytes_for_table() {
2949 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2950 }
2951
2952 void SystemDictionary::copy_buckets(char* top, char* end) {
2953 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2954 }
2955
2956 void SystemDictionary::copy_table(char* top, char* end) {
2957 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2958 }
2959
2960 // ----------------------------------------------------------------------------
2961 void SystemDictionary::print_shared(outputStream *st) {
2962 shared_dictionary()->print_on(st);
2963 }
2964
2965 void SystemDictionary::print_on(outputStream *st) {
2966 if (shared_dictionary() != NULL) {
2967 st->print_cr("Shared Dictionary");
2968 shared_dictionary()->print_on(st);
2969 st->cr();
2970 }
2971
2972 GCMutexLocker mu(SystemDictionary_lock);
2973
2974 ClassLoaderDataGraph::print_dictionary(st);
2975
2976 // Placeholders
2977 placeholders()->print_on(st);
2978 st->cr();
2979
2980 // loader constraints - print under SD_lock
2981 constraints()->print_on(st);
2982 st->cr();
2983
2984 _pd_cache_table->print_on(st);
2985 st->cr();
2986 }
2987
2988 void SystemDictionary::verify() {
2989 guarantee(constraints() != NULL,
2990 "Verify of loader constraints failed");
2991 guarantee(placeholders()->number_of_entries() >= 0,
2992 "Verify of placeholders failed");
2993
2994 GCMutexLocker mu(SystemDictionary_lock);
2995
2996 // Verify dictionary
2997 ClassLoaderDataGraph::verify_dictionary();
2998
2999 placeholders()->verify();
3000
3001 // Verify constraint table
3002 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3003 constraints()->verify(placeholders());
3004
3005 _pd_cache_table->verify();
3006 }
3007
3008 void SystemDictionary::dump(outputStream *st, bool verbose) {
3009 assert_locked_or_safepoint(SystemDictionary_lock);
3010 if (verbose) {
3011 print_on(st);
3012 } else {
3013 if (shared_dictionary() != NULL) {
3014 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3015 }
3016 ClassLoaderDataGraph::print_dictionary_statistics(st);
3017 placeholders()->print_table_statistics(st, "Placeholder Table");
3018 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3019 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3020 }
3021 }
3022
3023 // Utility for dumping dictionaries.
3024 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3025 DCmdWithParser(output, heap),
3026 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3027 "BOOLEAN", false, "false") {
3028 _dcmdparser.add_dcmd_option(&_verbose);
3029 }
3030
3031 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3032 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3033 _verbose.value());
3034 VMThread::execute(&dumper);
3035 }
3036
3037 int SystemDictionaryDCmd::num_arguments() {
3038 ResourceMark rm;
3039 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3040 if (dcmd != NULL) {
3041 DCmdMark mark(dcmd);
3042 return dcmd->_dcmdparser.num_arguments();
3043 } else {
3044 return 0;
3045 }
3046 }
3047
3048 class CombineDictionariesClosure : public CLDClosure {
3049 private:
3050 Dictionary* _master_dictionary;
3051 public:
3052 CombineDictionariesClosure(Dictionary* master_dictionary) :
3053 _master_dictionary(master_dictionary) {}
3054 void do_cld(ClassLoaderData* cld) {
3055 ResourceMark rm;
3056 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3057 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3058 Dictionary* curr_dictionary = cld->dictionary();
3059 DictionaryEntry* p = curr_dictionary->bucket(i);
3060 while (p != NULL) {
3061 Symbol* name = p->instance_klass()->name();
3062 unsigned int d_hash = _master_dictionary->compute_hash(name);
3063 int d_index = _master_dictionary->hash_to_index(d_hash);
3064 DictionaryEntry* next = p->next();
3065 if (p->literal()->class_loader_data() != cld) {
3066 // This is an initiating class loader entry; don't use it
3067 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3068 curr_dictionary->free_entry(p);
3069 } else {
3070 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3071 curr_dictionary->unlink_entry(p);
3072 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3073 _master_dictionary->add_entry(d_index, p);
3074 }
3075 p = next;
3076 }
3077 *curr_dictionary->bucket_addr(i) = NULL;
3078 }
3079 }
3080 }
3081 };
3082
3083 // Combining platform and system loader dictionaries into boot loader dictionaries.
3084 // During run time, we only have one shared dictionary.
3085 void SystemDictionary::combine_shared_dictionaries() {
3086 assert(DumpSharedSpaces, "dump time only");
3087 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3088 CombineDictionariesClosure cdc(master_dictionary);
3089 ClassLoaderDataGraph::cld_do(&cdc);
3090
3091 // These tables are no longer valid or necessary. Keeping them around will
3092 // cause SystemDictionary::verify() to fail. Let's empty them.
3093 _placeholders = new PlaceholderTable(_placeholder_table_size);
3094 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3095
3096 NOT_PRODUCT(SystemDictionary::verify());
3097 }
3098
3099 // caller needs ResourceMark
3100 const char* SystemDictionary::loader_name(const oop loader) {
3101 return ((loader) == NULL ? "<bootloader>" :
3102 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3103 }
3104
3105 // caller needs ResourceMark
3106 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3107 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3108 SystemDictionary::loader_name(loader_data->class_loader()));
3109 }