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/methodData.hpp"
60 #include "oops/objArrayKlass.hpp"
61 #include "oops/objArrayOop.inline.hpp"
62 #include "oops/oop.inline.hpp"
63 #include "oops/symbol.hpp"
64 #include "oops/typeArrayKlass.hpp"
65 #include "oops/valueKlass.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/os.hpp"
79 #include "runtime/signature.hpp"
80 #include "services/classLoadingService.hpp"
81 #include "services/diagnosticCommand.hpp"
82 #include "services/threadService.hpp"
83 #include "trace/tracing.hpp"
84 #include "utilities/macros.hpp"
85 #if INCLUDE_CDS
86 #include "classfile/sharedClassUtil.hpp"
87 #include "classfile/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_checkPackageAccess = false;
112
113 // lazily initialized klass variables
114 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
115
116 // Default ProtectionDomainCacheSize value
117
118 const int defaultProtectionDomainCacheSize = 1009;
119
120
121 // ----------------------------------------------------------------------------
122 // Java-level SystemLoader and PlatformLoader
123
124 oop SystemDictionary::java_system_loader() {
125 return _java_system_loader;
126 }
127
128 oop SystemDictionary::java_platform_loader() {
129 return _java_platform_loader;
130 }
131
132 void SystemDictionary::compute_java_loaders(TRAPS) {
133 JavaValue result(T_OBJECT);
134 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
135 JavaCalls::call_static(&result,
136 class_loader_klass,
137 vmSymbols::getSystemClassLoader_name(),
138 vmSymbols::void_classloader_signature(),
139 CHECK);
140
141 _java_system_loader = (oop)result.get_jobject();
142
143 JavaCalls::call_static(&result,
144 class_loader_klass,
145 vmSymbols::getPlatformClassLoader_name(),
146 vmSymbols::void_classloader_signature(),
147 CHECK);
148
149 _java_platform_loader = (oop)result.get_jobject();
150
151 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
152 }
153
154 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
155 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
156 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
157 }
158
159 // ----------------------------------------------------------------------------
160 // Parallel class loading check
161
162 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
163 if (class_loader.is_null()) return true;
164 if (AlwaysLockClassLoader) return false;
165 return java_lang_ClassLoader::parallelCapable(class_loader());
166 }
167 // ----------------------------------------------------------------------------
168 // ParallelDefineClass flag does not apply to bootclass loader
169 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
170 if (class_loader.is_null()) return false;
171 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
172 return true;
173 }
174 return false;
175 }
176
177 // Returns true if the passed class loader is the builtin application class loader
178 // or a custom system class loader. A customer system class loader can be
179 // specified via -Djava.system.class.loader.
180 bool SystemDictionary::is_system_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
185 class_loader == _java_system_loader);
186 }
187
188 // Returns true if the passed class loader is the platform class loader.
189 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
190 if (class_loader == NULL) {
191 return false;
192 }
193 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
194 }
195
196 // ----------------------------------------------------------------------------
197 // Resolving of classes
198
199 // Forwards to resolve_or_null
200
201 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
202 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
203 if (HAS_PENDING_EXCEPTION || klass == NULL) {
204 // can return a null klass
205 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
206 }
207 return klass;
208 }
209
210 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
211 bool throw_error,
212 Klass* klass, TRAPS) {
213 if (HAS_PENDING_EXCEPTION) {
214 // If we have a pending exception we forward it to the caller, unless throw_error is true,
215 // in which case we have to check whether the pending exception is a ClassNotFoundException,
216 // and if so convert it to a NoClassDefFoundError
217 // And chain the original ClassNotFoundException
218 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
219 ResourceMark rm(THREAD);
220 assert(klass == NULL, "Should not have result with exception pending");
221 Handle e(THREAD, PENDING_EXCEPTION);
222 CLEAR_PENDING_EXCEPTION;
223 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
224 } else {
225 return NULL;
226 }
227 }
228 // Class not found, throw appropriate error or exception depending on value of throw_error
229 if (klass == NULL) {
230 ResourceMark rm(THREAD);
231 if (throw_error) {
232 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
233 } else {
234 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
235 }
236 }
237 return klass;
238 }
239
240
241 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
242 bool throw_error, TRAPS)
243 {
244 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
245 }
246
247
248 // Forwards to resolve_instance_class_or_null
249
250 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
251 assert(THREAD->can_call_java(),
252 "can not load classes with compiler thread: class=%s, classloader=%s",
253 class_name->as_C_string(),
254 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
255 if (FieldType::is_array(class_name)) {
256 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
257 } else if (FieldType::is_obj(class_name)) {
258 ResourceMark rm(THREAD);
259 // Ignore wrapping L and ;. (and Q and ; for value types);
260 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
261 class_name->utf8_length() - 2, CHECK_NULL);
262 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
263 } else {
264 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
265 }
266 }
267
268 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
269 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
270 }
271
272 // Forwards to resolve_instance_class_or_null
273
274 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
275 Handle class_loader,
276 Handle protection_domain,
277 TRAPS) {
278 assert(FieldType::is_array(class_name), "must be array");
279 Klass* k = NULL;
280 FieldArrayInfo fd;
281 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
282 // of this call
283 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
284 if (t == T_OBJECT || t == T_VALUETYPE) {
285 // naked oop "k" is OK here -- we assign back into it
286 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
287 class_loader,
288 protection_domain,
289 CHECK_NULL);
290 if (k != NULL) {
291 k = k->array_klass(fd.dimension(), CHECK_NULL);
292 }
293 } else {
294 k = Universe::typeArrayKlassObj(t);
295 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
296 }
297 return k;
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 Klass* SystemDictionary::resolve_flattenable_field_or_fail(AllFieldStream* fs,
439 Handle class_loader,
440 Handle protection_domain,
441 bool throw_error,
442 TRAPS) {
443 Symbol* class_name = fs->signature();
444 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
445 ClassLoaderData* loader_data = class_loader_data(class_loader);
446 unsigned int p_hash = placeholders()->compute_hash(class_name);
447 int p_index = placeholders()->hash_to_index(p_hash);
448 bool throw_circularity_error = false;
449 PlaceholderEntry* oldprobe;
450
451 {
452 MutexLocker mu(SystemDictionary_lock, THREAD);
453 oldprobe = placeholders()->get_entry(p_index, p_hash, class_name, loader_data);
454 if (oldprobe != NULL &&
455 oldprobe->check_seen_thread(THREAD, PlaceholderTable::FLATTENABLE_FIELD)) {
456 throw_circularity_error = true;
457
458 } else {
459 placeholders()->find_and_add(p_index, p_hash, class_name, loader_data,
460 PlaceholderTable::FLATTENABLE_FIELD, NULL, THREAD);
461 }
462 }
463
464 Klass* klass = NULL;
465 if (!throw_circularity_error) {
466 klass = SystemDictionary::resolve_or_fail(class_name, class_loader,
467 protection_domain, true, THREAD);
468 } else {
469 ResourceMark rm(THREAD);
470 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), class_name->as_C_string());
471 }
472
473 {
474 MutexLocker mu(SystemDictionary_lock, THREAD);
475 placeholders()->find_and_remove(p_index, p_hash, class_name, loader_data,
476 PlaceholderTable::FLATTENABLE_FIELD, THREAD);
477 }
478
479 return klass;
480 }
481
482 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
483 Handle class_loader,
484 Handle protection_domain,
485 TRAPS) {
486 if(!has_checkPackageAccess()) return;
487
488 // Now we have to call back to java to check if the initating class has access
489 JavaValue result(T_VOID);
490 LogTarget(Debug, protectiondomain) lt;
491 if (lt.is_enabled()) {
492 ResourceMark rm;
493 // Print out trace information
494 LogStream ls(lt);
495 ls.print_cr("Checking package access");
496 ls.print("class loader: "); class_loader()->print_value_on(&ls);
497 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
498 ls.print(" loading: "); klass->print_value_on(&ls);
499 ls.cr();
500 }
501
502 // This handle and the class_loader handle passed in keeps this class from
503 // being unloaded through several GC points.
504 // The class_loader handle passed in is the initiating loader.
505 Handle mirror(THREAD, klass->java_mirror());
506
507 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
508 JavaCalls::call_special(&result,
509 class_loader,
510 system_loader,
511 vmSymbols::checkPackageAccess_name(),
512 vmSymbols::class_protectiondomain_signature(),
513 mirror,
514 protection_domain,
515 THREAD);
516
517 if (HAS_PENDING_EXCEPTION) {
518 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
519 } else {
520 log_debug(protectiondomain)("granted");
521 }
522
523 if (HAS_PENDING_EXCEPTION) return;
524
525 // If no exception has been thrown, we have validated the protection domain
526 // Insert the protection domain of the initiating class into the set.
527 {
528 ClassLoaderData* loader_data = class_loader_data(class_loader);
529 Dictionary* dictionary = loader_data->dictionary();
530
531 Symbol* kn = klass->name();
532 unsigned int d_hash = dictionary->compute_hash(kn);
533
534 MutexLocker mu(SystemDictionary_lock, THREAD);
535 int d_index = dictionary->hash_to_index(d_hash);
536 dictionary->add_protection_domain(d_index, d_hash, klass,
537 protection_domain, THREAD);
538 }
539 }
540
541 // We only get here if this thread finds that another thread
542 // has already claimed the placeholder token for the current operation,
543 // but that other thread either never owned or gave up the
544 // object lock
545 // Waits on SystemDictionary_lock to indicate placeholder table updated
546 // On return, caller must recheck placeholder table state
547 //
548 // We only get here if
549 // 1) custom classLoader, i.e. not bootstrap classloader
550 // 2) custom classLoader has broken the class loader objectLock
551 // so another thread got here in parallel
552 //
553 // lockObject must be held.
554 // Complicated dance due to lock ordering:
555 // Must first release the classloader object lock to
556 // allow initial definer to complete the class definition
557 // and to avoid deadlock
558 // Reclaim classloader lock object with same original recursion count
559 // Must release SystemDictionary_lock after notify, since
560 // class loader lock must be claimed before SystemDictionary_lock
561 // to prevent deadlocks
562 //
563 // The notify allows applications that did an untimed wait() on
564 // the classloader object lock to not hang.
565 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
566 assert_lock_strong(SystemDictionary_lock);
567
568 bool calledholdinglock
569 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
570 assert(calledholdinglock,"must hold lock for notify");
571 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
572 ObjectSynchronizer::notifyall(lockObject, THREAD);
573 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
574 SystemDictionary_lock->wait();
575 SystemDictionary_lock->unlock();
576 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
577 SystemDictionary_lock->lock();
578 }
579
580 // If the class in is in the placeholder table, class loading is in progress
581 // For cases where the application changes threads to load classes, it
582 // is critical to ClassCircularity detection that we try loading
583 // the superclass on the same thread internally, so we do parallel
584 // super class loading here.
585 // This also is critical in cases where the original thread gets stalled
586 // even in non-circularity situations.
587 // Note: must call resolve_super_or_fail even if null super -
588 // to force placeholder entry creation for this class for circularity detection
589 // Caller must check for pending exception
590 // Returns non-null Klass* if other thread has completed load
591 // and we are done,
592 // If return null Klass* and no pending exception, the caller must load the class
593 InstanceKlass* SystemDictionary::handle_parallel_super_load(
594 Symbol* name, Symbol* superclassname, Handle class_loader,
595 Handle protection_domain, Handle lockObject, TRAPS) {
596
597 ClassLoaderData* loader_data = class_loader_data(class_loader);
598 Dictionary* dictionary = loader_data->dictionary();
599 unsigned int d_hash = dictionary->compute_hash(name);
600 unsigned int p_hash = placeholders()->compute_hash(name);
601 int p_index = placeholders()->hash_to_index(p_hash);
602
603 // superk is not used, resolve_super called for circularity check only
604 // This code is reached in two situations. One if this thread
605 // is loading the same class twice (e.g. ClassCircularity, or
606 // java.lang.instrument).
607 // The second is if another thread started the resolve_super first
608 // and has not yet finished.
609 // In both cases the original caller will clean up the placeholder
610 // entry on error.
611 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
612 superclassname,
613 class_loader,
614 protection_domain,
615 true,
616 CHECK_NULL);
617
618 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
619 // Serial class loaders and bootstrap classloader do wait for superclass loads
620 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
621 MutexLocker mu(SystemDictionary_lock, THREAD);
622 // Check if classloading completed while we were loading superclass or waiting
623 return find_class(d_hash, name, dictionary);
624 }
625
626 // must loop to both handle other placeholder updates
627 // and spurious notifications
628 bool super_load_in_progress = true;
629 PlaceholderEntry* placeholder;
630 while (super_load_in_progress) {
631 MutexLocker mu(SystemDictionary_lock, THREAD);
632 // Check if classloading completed while we were loading superclass or waiting
633 InstanceKlass* check = find_class(d_hash, name, dictionary);
634 if (check != NULL) {
635 // Klass is already loaded, so just return it
636 return check;
637 } else {
638 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
639 if (placeholder && placeholder->super_load_in_progress() ){
640 // We only get here if the application has released the
641 // classloader lock when another thread was in the middle of loading a
642 // superclass/superinterface for this class, and now
643 // this thread is also trying to load this class.
644 // To minimize surprises, the first thread that started to
645 // load a class should be the one to complete the loading
646 // with the classfile it initially expected.
647 // This logic has the current thread wait once it has done
648 // all the superclass/superinterface loading it can, until
649 // the original thread completes the class loading or fails
650 // If it completes we will use the resulting InstanceKlass
651 // which we will find below in the systemDictionary.
652 // We also get here for parallel bootstrap classloader
653 if (class_loader.is_null()) {
654 SystemDictionary_lock->wait();
655 } else {
656 double_lock_wait(lockObject, THREAD);
657 }
658 } else {
659 // If not in SD and not in PH, other thread's load must have failed
660 super_load_in_progress = false;
661 }
662 }
663 }
664 return NULL;
665 }
666
667 static void post_class_load_event(EventClassLoad* event,
668 const InstanceKlass* k,
669 const ClassLoaderData* init_cld) {
670 #if INCLUDE_TRACE
671 assert(event != NULL, "invariant");
672 assert(k != NULL, "invariant");
673 if (event->should_commit()) {
674 event->set_loadedClass(k);
675 event->set_definingClassLoader(k->class_loader_data());
676 event->set_initiatingClassLoader(init_cld);
677 event->commit();
678 }
679 #endif // INCLUDE_TRACE
680 }
681
682 static void class_define_event(InstanceKlass* k,
683 const ClassLoaderData* def_cld) {
684 #if INCLUDE_TRACE
685 EventClassDefine event;
686 if (event.should_commit()) {
687 event.set_definedClass(k);
688 event.set_definingClassLoader(def_cld);
689 event.commit();
690 }
691 #endif // INCLUDE_TRACE
692 }
693
694 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
695 Handle class_loader,
696 Handle protection_domain,
697 TRAPS) {
698 Klass* k = do_resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
699 return k;
700 }
701
702 // Be careful when modifying this code: once you have run
703 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
704 // you need to find_and_remove it before returning.
705 // So be careful to not exit with a CHECK_ macro betweeen these calls.
706 Klass* SystemDictionary::do_resolve_instance_class_or_null(Symbol* name,
707 Handle class_loader,
708 Handle protection_domain,
709 TRAPS) {
710 assert(name != NULL && !FieldType::is_array(name) &&
711 !FieldType::is_obj(name), "invalid class name");
712
713 EventClassLoad class_load_start_event;
714
715 HandleMark hm(THREAD);
716
717 // Fix for 4474172; see evaluation for more details
718 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
719 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
720 Dictionary* dictionary = loader_data->dictionary();
721 unsigned int d_hash = dictionary->compute_hash(name);
722
723 // Do lookup to see if class already exist and the protection domain
724 // has the right access
725 // This call uses find which checks protection domain already matches
726 // All subsequent calls use find_class, and set has_loaded_class so that
727 // before we return a result we call out to java to check for valid protection domain
728 // to allow returning the Klass* and add it to the pd_set if it is valid
729 {
730 Klass* probe = dictionary->find(d_hash, name, protection_domain);
731 if (probe != NULL) return probe;
732 }
733
734 // Non-bootstrap class loaders will call out to class loader and
735 // define via jvm/jni_DefineClass which will acquire the
736 // class loader object lock to protect against multiple threads
737 // defining the class in parallel by accident.
738 // This lock must be acquired here so the waiter will find
739 // any successful result in the SystemDictionary and not attempt
740 // the define.
741 // ParallelCapable Classloaders and the bootstrap classloader
742 // do not acquire lock here.
743 bool DoObjectLock = true;
744 if (is_parallelCapable(class_loader)) {
745 DoObjectLock = false;
746 }
747
748 unsigned int p_hash = placeholders()->compute_hash(name);
749 int p_index = placeholders()->hash_to_index(p_hash);
750
751 // Class is not in SystemDictionary so we have to do loading.
752 // Make sure we are synchronized on the class loader before we proceed
753 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
754 check_loader_lock_contention(lockObject, THREAD);
755 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
756
757 // Check again (after locking) if class already exist in SystemDictionary
758 bool class_has_been_loaded = false;
759 bool super_load_in_progress = false;
760 bool havesupername = false;
761 InstanceKlass* k = NULL;
762 PlaceholderEntry* placeholder;
763 Symbol* superclassname = NULL;
764
765 {
766 MutexLocker mu(SystemDictionary_lock, THREAD);
767 InstanceKlass* check = find_class(d_hash, name, dictionary);
768 if (check != NULL) {
769 // Klass is already loaded, so just return it
770 class_has_been_loaded = true;
771 k = check;
772 } else {
773 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
774 if (placeholder && placeholder->super_load_in_progress()) {
775 super_load_in_progress = true;
776 if (placeholder->havesupername() == true) {
777 superclassname = placeholder->supername();
778 havesupername = true;
779 }
780 }
781 }
782 }
783
784 // If the class is in the placeholder table, class loading is in progress
785 if (super_load_in_progress && havesupername==true) {
786 k = handle_parallel_super_load(name,
787 superclassname,
788 class_loader,
789 protection_domain,
790 lockObject, THREAD);
791 if (HAS_PENDING_EXCEPTION) {
792 return NULL;
793 }
794 if (k != NULL) {
795 class_has_been_loaded = true;
796 }
797 }
798
799 bool throw_circularity_error = false;
800 if (!class_has_been_loaded) {
801 bool load_instance_added = false;
802
803 // add placeholder entry to record loading instance class
804 // Five cases:
805 // All cases need to prevent modifying bootclasssearchpath
806 // in parallel with a classload of same classname
807 // Redefineclasses uses existence of the placeholder for the duration
808 // of the class load to prevent concurrent redefinition of not completely
809 // defined classes.
810 // case 1. traditional classloaders that rely on the classloader object lock
811 // - no other need for LOAD_INSTANCE
812 // case 2. traditional classloaders that break the classloader object lock
813 // as a deadlock workaround. Detection of this case requires that
814 // this check is done while holding the classloader object lock,
815 // and that lock is still held when calling classloader's loadClass.
816 // For these classloaders, we ensure that the first requestor
817 // completes the load and other requestors wait for completion.
818 // case 3. Bootstrap classloader - don't own objectLocker
819 // This classloader supports parallelism at the classloader level,
820 // but only allows a single load of a class/classloader pair.
821 // No performance benefit and no deadlock issues.
822 // case 4. parallelCapable user level classloaders - without objectLocker
823 // Allow parallel classloading of a class/classloader pair
824
825 {
826 MutexLocker mu(SystemDictionary_lock, THREAD);
827 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
828 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
829 if (oldprobe) {
830 // only need check_seen_thread once, not on each loop
831 // 6341374 java/lang/Instrument with -Xcomp
832 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
833 throw_circularity_error = true;
834 } else {
835 // case 1: traditional: should never see load_in_progress.
836 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
837
838 // case 3: bootstrap classloader: prevent futile classloading,
839 // wait on first requestor
840 if (class_loader.is_null()) {
841 SystemDictionary_lock->wait();
842 } else {
843 // case 2: traditional with broken classloader lock. wait on first
844 // requestor.
845 double_lock_wait(lockObject, THREAD);
846 }
847 // Check if classloading completed while we were waiting
848 InstanceKlass* check = find_class(d_hash, name, dictionary);
849 if (check != NULL) {
850 // Klass is already loaded, so just return it
851 k = check;
852 class_has_been_loaded = true;
853 }
854 // check if other thread failed to load and cleaned up
855 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
856 }
857 }
858 }
859 }
860 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
861 // case 4: parallelCapable: allow competing threads to try
862 // LOAD_INSTANCE in parallel
863
864 if (!throw_circularity_error && !class_has_been_loaded) {
865 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
866 load_instance_added = true;
867 // For class loaders that do not acquire the classloader object lock,
868 // if they did not catch another thread holding LOAD_INSTANCE,
869 // need a check analogous to the acquire ObjectLocker/find_class
870 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
871 // one final check if the load has already completed
872 // class loaders holding the ObjectLock shouldn't find the class here
873 InstanceKlass* check = find_class(d_hash, name, dictionary);
874 if (check != NULL) {
875 // Klass is already loaded, so return it after checking/adding protection domain
876 k = check;
877 class_has_been_loaded = true;
878 }
879 }
880 }
881
882 // must throw error outside of owning lock
883 if (throw_circularity_error) {
884 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
885 ResourceMark rm(THREAD);
886 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
887 }
888
889 if (!class_has_been_loaded) {
890
891 // Do actual loading
892 k = load_instance_class(name, class_loader, THREAD);
893
894 // If everything was OK (no exceptions, no null return value), and
895 // class_loader is NOT the defining loader, do a little more bookkeeping.
896 if (!HAS_PENDING_EXCEPTION && k != NULL &&
897 k->class_loader() != class_loader()) {
898
899 check_constraints(d_hash, k, class_loader, false, THREAD);
900
901 // Need to check for a PENDING_EXCEPTION again; check_constraints
902 // can throw and doesn't use the CHECK macro.
903 if (!HAS_PENDING_EXCEPTION) {
904 { // Grabbing the Compile_lock prevents systemDictionary updates
905 // during compilations.
906 MutexLocker mu(Compile_lock, THREAD);
907 update_dictionary(d_hash, p_index, p_hash,
908 k, class_loader, THREAD);
909 }
910
911 if (JvmtiExport::should_post_class_load()) {
912 Thread *thread = THREAD;
913 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
914 JvmtiExport::post_class_load((JavaThread *) thread, k);
915 }
916 }
917 }
918 } // load_instance_class
919
920 if (load_instance_added == true) {
921 // clean up placeholder entries for LOAD_INSTANCE success or error
922 // This brackets the SystemDictionary updates for both defining
923 // and initiating loaders
924 MutexLocker mu(SystemDictionary_lock, THREAD);
925 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
926 SystemDictionary_lock->notify_all();
927 }
928 }
929
930 if (HAS_PENDING_EXCEPTION || k == NULL) {
931 return NULL;
932 }
933
934 post_class_load_event(&class_load_start_event, k, loader_data);
935
936 #ifdef ASSERT
937 {
938 ClassLoaderData* loader_data = k->class_loader_data();
939 MutexLocker mu(SystemDictionary_lock, THREAD);
940 Klass* kk = find_class(name, loader_data);
941 assert(kk == k, "should be present in dictionary");
942 }
943 #endif
944
945 // return if the protection domain in NULL
946 if (protection_domain() == NULL) return k;
947
948 // Check the protection domain has the right access
949 if (dictionary->is_valid_protection_domain(d_hash, name,
950 protection_domain)) {
951 return k;
952 }
953
954 // Verify protection domain. If it fails an exception is thrown
955 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
956
957 return k;
958 }
959
960
961 // This routine does not lock the system dictionary.
962 //
963 // Since readers don't hold a lock, we must make sure that system
964 // dictionary entries are only removed at a safepoint (when only one
965 // thread is running), and are added to in a safe way (all links must
966 // be updated in an MT-safe manner).
967 //
968 // Callers should be aware that an entry could be added just after
969 // _dictionary->bucket(index) is read here, so the caller will not see
970 // the new entry.
971
972 Klass* SystemDictionary::find(Symbol* class_name,
973 Handle class_loader,
974 Handle protection_domain,
975 TRAPS) {
976
977 // The result of this call should be consistent with the result
978 // of the call to resolve_instance_class_or_null().
979 // See evaluation 6790209 and 4474172 for more details.
980 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
981 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
982
983 if (loader_data == NULL) {
984 // If the ClassLoaderData has not been setup,
985 // then the class loader has no entries in the dictionary.
986 return NULL;
987 }
988
989 Dictionary* dictionary = loader_data->dictionary();
990 unsigned int d_hash = dictionary->compute_hash(class_name);
991 return dictionary->find(d_hash, class_name,
992 protection_domain);
993 }
994
995
996 // Look for a loaded instance or array klass by name. Do not do any loading.
997 // return NULL in case of error.
998 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
999 Handle class_loader,
1000 Handle protection_domain,
1001 TRAPS) {
1002 Klass* k = NULL;
1003 assert(class_name != NULL, "class name must be non NULL");
1004
1005 if (FieldType::is_array(class_name)) {
1006 // The name refers to an array. Parse the name.
1007 // dimension and object_key in FieldArrayInfo are assigned as a
1008 // side-effect of this call
1009 FieldArrayInfo fd;
1010 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1011 if (t != T_OBJECT && t != T_VALUETYPE) {
1012 k = Universe::typeArrayKlassObj(t);
1013 } else {
1014 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1015 }
1016 if (k != NULL) {
1017 k = k->array_klass_or_null(fd.dimension());
1018 }
1019 } else {
1020 k = find(class_name, class_loader, protection_domain, THREAD);
1021 }
1022 return k;
1023 }
1024
1025 // Note: this method is much like resolve_from_stream, but
1026 // does not publish the classes via the SystemDictionary.
1027 // Handles unsafe_DefineAnonymousClass and redefineclasses
1028 // RedefinedClasses do not add to the class hierarchy
1029 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1030 Handle class_loader,
1031 Handle protection_domain,
1032 ClassFileStream* st,
1033 const InstanceKlass* host_klass,
1034 GrowableArray<Handle>* cp_patches,
1035 TRAPS) {
1036
1037 EventClassLoad class_load_start_event;
1038
1039 ClassLoaderData* loader_data;
1040 if (host_klass != NULL) {
1041 // Create a new CLD for anonymous class, that uses the same class loader
1042 // as the host_klass
1043 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1044 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1045 } else {
1046 loader_data = ClassLoaderData::class_loader_data(class_loader());
1047 }
1048
1049 assert(st != NULL, "invariant");
1050 assert(st->need_verify(), "invariant");
1051
1052 // Parse stream and create a klass.
1053 // Note that we do this even though this klass might
1054 // already be present in the SystemDictionary, otherwise we would not
1055 // throw potential ClassFormatErrors.
1056
1057 InstanceKlass* k = KlassFactory::create_from_stream(st,
1058 class_name,
1059 loader_data,
1060 protection_domain,
1061 host_klass,
1062 cp_patches,
1063 CHECK_NULL);
1064
1065 if (host_klass != NULL && k != NULL) {
1066 // If it's anonymous, initialize it now, since nobody else will.
1067
1068 {
1069 MutexLocker mu_r(Compile_lock, THREAD);
1070
1071 // Add to class hierarchy, initialize vtables, and do possible
1072 // deoptimizations.
1073 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1074
1075 // But, do not add to dictionary.
1076
1077 // compiled code dependencies need to be validated anyway
1078 notice_modification();
1079 }
1080
1081 // Rewrite and patch constant pool here.
1082 k->link_class(CHECK_NULL);
1083 if (cp_patches != NULL) {
1084 k->constants()->patch_resolved_references(cp_patches);
1085 }
1086 k->eager_initialize(CHECK_NULL);
1087
1088 // notify jvmti
1089 if (JvmtiExport::should_post_class_load()) {
1090 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1091 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1092 }
1093
1094 post_class_load_event(&class_load_start_event, k, loader_data);
1095 }
1096 assert(host_klass != NULL || NULL == cp_patches,
1097 "cp_patches only found with host_klass");
1098
1099 return k;
1100 }
1101
1102 // Add a klass to the system from a stream (called by jni_DefineClass and
1103 // JVM_DefineClass).
1104 // Note: class_name can be NULL. In that case we do not know the name of
1105 // the class until we have parsed the stream.
1106
1107 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1108 Handle class_loader,
1109 Handle protection_domain,
1110 ClassFileStream* st,
1111 TRAPS) {
1112 #if INCLUDE_CDS
1113 ResourceMark rm(THREAD);
1114 if (DumpSharedSpaces && !class_loader.is_null() &&
1115 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1116 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1117 // class, which is used by MethodHandles).
1118 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1119 }
1120 #endif
1121
1122 HandleMark hm(THREAD);
1123
1124 // Classloaders that support parallelism, e.g. bootstrap classloader,
1125 // do not acquire lock here
1126 bool DoObjectLock = true;
1127 if (is_parallelCapable(class_loader)) {
1128 DoObjectLock = false;
1129 }
1130
1131 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1132
1133 // Make sure we are synchronized on the class loader before we proceed
1134 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1135 check_loader_lock_contention(lockObject, THREAD);
1136 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1137
1138 assert(st != NULL, "invariant");
1139
1140 // Parse the stream and create a klass.
1141 // Note that we do this even though this klass might
1142 // already be present in the SystemDictionary, otherwise we would not
1143 // throw potential ClassFormatErrors.
1144 InstanceKlass* k = NULL;
1145
1146 #if INCLUDE_CDS
1147 if (!DumpSharedSpaces) {
1148 k = SystemDictionaryShared::lookup_from_stream(class_name,
1149 class_loader,
1150 protection_domain,
1151 st,
1152 CHECK_NULL);
1153 }
1154 #endif
1155
1156 if (k == NULL) {
1157 if (st->buffer() == NULL) {
1158 return NULL;
1159 }
1160 k = KlassFactory::create_from_stream(st,
1161 class_name,
1162 loader_data,
1163 protection_domain,
1164 NULL, // host_klass
1165 NULL, // cp_patches
1166 CHECK_NULL);
1167 }
1168
1169 assert(k != NULL, "no klass created");
1170 Symbol* h_name = k->name();
1171 assert(class_name == NULL || class_name == h_name, "name mismatch");
1172
1173 // Add class just loaded
1174 // If a class loader supports parallel classloading handle parallel define requests
1175 // find_or_define_instance_class may return a different InstanceKlass
1176 if (is_parallelCapable(class_loader)) {
1177 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1178 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1179 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1180 assert(defined_k != NULL, "Should have a klass if there's no exception");
1181 loader_data->add_to_deallocate_list(k);
1182 k = defined_k;
1183 }
1184 } else {
1185 define_instance_class(k, THREAD);
1186 }
1187
1188 // If defining the class throws an exception register 'k' for cleanup.
1189 if (HAS_PENDING_EXCEPTION) {
1190 assert(k != NULL, "Must have an instance klass here!");
1191 loader_data->add_to_deallocate_list(k);
1192 return NULL;
1193 }
1194
1195 // Make sure we have an entry in the SystemDictionary on success
1196 debug_only( {
1197 MutexLocker mu(SystemDictionary_lock, THREAD);
1198
1199 Klass* check = find_class(h_name, k->class_loader_data());
1200 assert(check == k, "should be present in the dictionary");
1201 } );
1202
1203 return k;
1204 }
1205
1206 #if INCLUDE_CDS
1207 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1208 int number_of_entries) {
1209 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1210 "bad shared dictionary size.");
1211 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1212 _shared_dictionary_size, t, number_of_entries);
1213 }
1214
1215
1216 // If there is a shared dictionary, then find the entry for the
1217 // given shared system class, if any.
1218
1219 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1220 if (shared_dictionary() != NULL) {
1221 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1222 int d_index = shared_dictionary()->hash_to_index(d_hash);
1223
1224 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1225 } else {
1226 return NULL;
1227 }
1228 }
1229
1230
1231 // Load a class from the shared spaces (found through the shared system
1232 // dictionary). Force the superclass and all interfaces to be loaded.
1233 // Update the class definition to include sibling classes and no
1234 // subclasses (yet). [Classes in the shared space are not part of the
1235 // object hierarchy until loaded.]
1236
1237 InstanceKlass* SystemDictionary::load_shared_class(
1238 Symbol* class_name, Handle class_loader, TRAPS) {
1239 InstanceKlass* ik = find_shared_class(class_name);
1240 // Make sure we only return the boot class for the NULL classloader.
1241 if (ik != NULL &&
1242 ik->is_shared_boot_class() && class_loader.is_null()) {
1243 Handle protection_domain;
1244 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1245 }
1246 return NULL;
1247 }
1248
1249 // Check if a shared class can be loaded by the specific classloader:
1250 //
1251 // NULL classloader:
1252 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1253 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1254 // be defined in an unnamed module.
1255 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1256 InstanceKlass* ik,
1257 Handle class_loader, TRAPS) {
1258 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1259 "Cannot use sharing if java.base is patched");
1260 ResourceMark rm;
1261 int path_index = ik->shared_classpath_index();
1262 ClassLoaderData* loader_data = class_loader_data(class_loader);
1263 if (path_index < 0) {
1264 // path_index < 0 indicates that the class is intended for a custom loader
1265 // and should not be loaded by boot/platform/app loaders
1266 if (loader_data->is_builtin_class_loader_data()) {
1267 return false;
1268 } else {
1269 return true;
1270 }
1271 }
1272 SharedClassPathEntry* ent =
1273 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1274 if (!Universe::is_module_initialized()) {
1275 assert(ent != NULL && ent->is_modules_image(),
1276 "Loading non-bootstrap classes before the module system is initialized");
1277 assert(class_loader.is_null(), "sanity");
1278 return true;
1279 }
1280 // Get the pkg_entry from the classloader
1281 TempNewSymbol pkg_name = NULL;
1282 PackageEntry* pkg_entry = NULL;
1283 ModuleEntry* mod_entry = NULL;
1284 const char* pkg_string = NULL;
1285 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1286 if (pkg_name != NULL) {
1287 pkg_string = pkg_name->as_C_string();
1288 if (loader_data != NULL) {
1289 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1290 }
1291 if (pkg_entry != NULL) {
1292 mod_entry = pkg_entry->module();
1293 }
1294 }
1295
1296 // If the archived class is from a module that has been patched at runtime,
1297 // the class cannot be loaded from the archive.
1298 if (mod_entry != NULL && mod_entry->is_patched()) {
1299 return false;
1300 }
1301
1302 if (class_loader.is_null()) {
1303 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1304 // The NULL classloader can load archived class originated from the
1305 // "modules" jimage and the -Xbootclasspath/a. For class from the
1306 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1307 // by the NULL classloader.
1308 if (mod_entry != NULL) {
1309 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1310 // ModuleEntry's location agrees with the archived class' origination.
1311 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1312 return true; // Module class from the "module" jimage
1313 }
1314 }
1315
1316 // If the archived class is not from the "module" jimage, the class can be
1317 // loaded by the NULL classloader if
1318 //
1319 // 1. the class is from the unamed package
1320 // 2. or, the class is not from a module defined in the NULL classloader
1321 // 3. or, the class is from an unamed module
1322 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1323 // the class is from the -Xbootclasspath/a
1324 if (pkg_string == NULL ||
1325 pkg_entry == NULL ||
1326 pkg_entry->in_unnamed_module()) {
1327 assert(mod_entry == NULL ||
1328 mod_entry == loader_data->unnamed_module(),
1329 "the unnamed module is not defined in the classloader");
1330 return true;
1331 }
1332 }
1333 return false;
1334 } else {
1335 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1336 ik, class_loader, pkg_string, pkg_name,
1337 pkg_entry, mod_entry, CHECK_(false));
1338 return res;
1339 }
1340 }
1341
1342 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1343 Handle class_loader,
1344 Handle protection_domain, TRAPS) {
1345
1346 if (ik != NULL) {
1347 Symbol* class_name = ik->name();
1348
1349 bool visible = is_shared_class_visible(
1350 class_name, ik, class_loader, CHECK_NULL);
1351 if (!visible) {
1352 return NULL;
1353 }
1354
1355 // Resolve the superclass and interfaces. They must be the same
1356 // as in dump time, because the layout of <ik> depends on
1357 // the specific layout of ik->super() and ik->local_interfaces().
1358 //
1359 // If unexpected superclass or interfaces are found, we cannot
1360 // load <ik> from the shared archive.
1361
1362 if (ik->super() != NULL) {
1363 Symbol* cn = ik->super()->name();
1364 Klass *s = resolve_super_or_fail(class_name, cn,
1365 class_loader, protection_domain, true, CHECK_NULL);
1366 if (s != ik->super()) {
1367 // The dynamically resolved super class is not the same as the one we used during dump time,
1368 // so we cannot use ik.
1369 return NULL;
1370 } else {
1371 assert(s->is_shared(), "must be");
1372 }
1373 }
1374
1375 Array<Klass*>* interfaces = ik->local_interfaces();
1376 int num_interfaces = interfaces->length();
1377 for (int index = 0; index < num_interfaces; index++) {
1378 Klass* k = interfaces->at(index);
1379 Symbol* name = k->name();
1380 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1381 if (k != i) {
1382 // The dynamically resolved interface class is not the same as the one we used during dump time,
1383 // so we cannot use ik.
1384 return NULL;
1385 } else {
1386 assert(i->is_shared(), "must be");
1387 }
1388 }
1389
1390 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1391 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1392 if (new_ik != NULL) {
1393 // The class is changed by CFLH. Return the new class. The shared class is
1394 // not used.
1395 return new_ik;
1396 }
1397
1398 // Adjust methods to recover missing data. They need addresses for
1399 // interpreter entry points and their default native method address
1400 // must be reset.
1401
1402 // Updating methods must be done under a lock so multiple
1403 // threads don't update these in parallel
1404 //
1405 // Shared classes are all currently loaded by either the bootstrap or
1406 // internal parallel class loaders, so this will never cause a deadlock
1407 // on a custom class loader lock.
1408
1409 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1410 {
1411 HandleMark hm(THREAD);
1412 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1413 check_loader_lock_contention(lockObject, THREAD);
1414 ObjectLocker ol(lockObject, THREAD, true);
1415 // prohibited package check assumes all classes loaded from archive call
1416 // restore_unshareable_info which calls ik->set_package()
1417 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1418 }
1419
1420 ik->print_class_load_logging(loader_data, NULL, NULL);
1421
1422 // For boot loader, ensure that GetSystemPackage knows that a class in this
1423 // package was loaded.
1424 if (class_loader.is_null()) {
1425 int path_index = ik->shared_classpath_index();
1426 ResourceMark rm;
1427 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1428 }
1429
1430 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1431 // Only dump the classes that can be stored into CDS archive
1432 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1433 ResourceMark rm(THREAD);
1434 classlist_file->print_cr("%s", ik->name()->as_C_string());
1435 classlist_file->flush();
1436 }
1437 }
1438
1439 // notify a class loaded from shared object
1440 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1441 }
1442
1443 ik->set_has_passed_fingerprint_check(false);
1444 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1445 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1446 uint64_t cds_fp = ik->get_stored_fingerprint();
1447 if (aot_fp != 0 && aot_fp == cds_fp) {
1448 // This class matches with a class saved in an AOT library
1449 ik->set_has_passed_fingerprint_check(true);
1450 } else {
1451 ResourceMark rm;
1452 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1453 }
1454 }
1455 return ik;
1456 }
1457
1458 void SystemDictionary::clear_invoke_method_table() {
1459 SymbolPropertyEntry* spe = NULL;
1460 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1461 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1462 while (p != NULL) {
1463 spe = p;
1464 p = p->next();
1465 _invoke_method_table->free_entry(spe);
1466 }
1467 }
1468 }
1469 #endif // INCLUDE_CDS
1470
1471 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1472
1473 if (class_loader.is_null()) {
1474 ResourceMark rm;
1475 PackageEntry* pkg_entry = NULL;
1476 bool search_only_bootloader_append = false;
1477 ClassLoaderData *loader_data = class_loader_data(class_loader);
1478
1479 // Find the package in the boot loader's package entry table.
1480 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1481 if (pkg_name != NULL) {
1482 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1483 }
1484
1485 // Prior to attempting to load the class, enforce the boot loader's
1486 // visibility boundaries.
1487 if (!Universe::is_module_initialized()) {
1488 // During bootstrapping, prior to module initialization, any
1489 // class attempting to be loaded must be checked against the
1490 // java.base packages in the boot loader's PackageEntryTable.
1491 // No class outside of java.base is allowed to be loaded during
1492 // this bootstrapping window.
1493 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1494 // Class is either in the unnamed package or in
1495 // a named package within the unnamed module. Either
1496 // case is outside of java.base, do not attempt to
1497 // load the class post java.base definition. If
1498 // java.base has not been defined, let the class load
1499 // and its package will be checked later by
1500 // ModuleEntryTable::verify_javabase_packages.
1501 if (ModuleEntryTable::javabase_defined()) {
1502 return NULL;
1503 }
1504 } else {
1505 // Check that the class' package is defined within java.base.
1506 ModuleEntry* mod_entry = pkg_entry->module();
1507 Symbol* mod_entry_name = mod_entry->name();
1508 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1509 return NULL;
1510 }
1511 }
1512 } else {
1513 // After the module system has been initialized, check if the class'
1514 // package is in a module defined to the boot loader.
1515 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1516 // Class is either in the unnamed package, in a named package
1517 // within a module not defined to the boot loader or in a
1518 // a named package within the unnamed module. In all cases,
1519 // limit visibility to search for the class only in the boot
1520 // loader's append path.
1521 search_only_bootloader_append = true;
1522 }
1523 }
1524
1525 // Prior to bootstrapping's module initialization, never load a class outside
1526 // of the boot loader's module path
1527 assert(Universe::is_module_initialized() ||
1528 !search_only_bootloader_append,
1529 "Attempt to load a class outside of boot loader's module path");
1530
1531 // Search the shared system dictionary for classes preloaded into the
1532 // shared spaces.
1533 InstanceKlass* k = NULL;
1534 {
1535 #if INCLUDE_CDS
1536 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1537 k = load_shared_class(class_name, class_loader, THREAD);
1538 #endif
1539 }
1540
1541 if (k == NULL) {
1542 // Use VM class loader
1543 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1544 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1545 }
1546
1547 // find_or_define_instance_class may return a different InstanceKlass
1548 if (k != NULL) {
1549 InstanceKlass* defined_k =
1550 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1551 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1552 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1553 assert(defined_k != NULL, "Should have a klass if there's no exception");
1554 loader_data->add_to_deallocate_list(k);
1555 k = defined_k;
1556 } else if (HAS_PENDING_EXCEPTION) {
1557 loader_data->add_to_deallocate_list(k);
1558 return NULL;
1559 }
1560 }
1561 return k;
1562 } else {
1563 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1564 ResourceMark rm(THREAD);
1565
1566 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1567 JavaThread* jt = (JavaThread*) THREAD;
1568
1569 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1570 ClassLoader::perf_app_classload_selftime(),
1571 ClassLoader::perf_app_classload_count(),
1572 jt->get_thread_stat()->perf_recursion_counts_addr(),
1573 jt->get_thread_stat()->perf_timers_addr(),
1574 PerfClassTraceTime::CLASS_LOAD);
1575
1576 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1577 // Translate to external class name format, i.e., convert '/' chars to '.'
1578 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1579
1580 JavaValue result(T_OBJECT);
1581
1582 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1583
1584 // Call public unsynchronized loadClass(String) directly for all class loaders.
1585 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1586 // acquire a class-name based lock rather than the class loader object lock.
1587 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1588 JavaCalls::call_virtual(&result,
1589 class_loader,
1590 spec_klass,
1591 vmSymbols::loadClass_name(),
1592 vmSymbols::string_class_signature(),
1593 string,
1594 CHECK_NULL);
1595
1596 assert(result.get_type() == T_OBJECT, "just checking");
1597 oop obj = (oop) result.get_jobject();
1598
1599 // Primitive classes return null since forName() can not be
1600 // used to obtain any of the Class objects representing primitives or void
1601 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1602 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1603 // For user defined Java class loaders, check that the name returned is
1604 // the same as that requested. This check is done for the bootstrap
1605 // loader when parsing the class file.
1606 if (class_name == k->name()) {
1607 return k;
1608 }
1609 }
1610 // Class is not found or has the wrong name, return NULL
1611 return NULL;
1612 }
1613 }
1614
1615 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1616
1617 HandleMark hm(THREAD);
1618 ClassLoaderData* loader_data = k->class_loader_data();
1619 Handle class_loader_h(THREAD, loader_data->class_loader());
1620
1621 // for bootstrap and other parallel classloaders don't acquire lock,
1622 // use placeholder token
1623 // If a parallelCapable class loader calls define_instance_class instead of
1624 // find_or_define_instance_class to get here, we have a timing
1625 // hole with systemDictionary updates and check_constraints
1626 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1627 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1628 compute_loader_lock_object(class_loader_h, THREAD)),
1629 "define called without lock");
1630 }
1631
1632 // Check class-loading constraints. Throw exception if violation is detected.
1633 // Grabs and releases SystemDictionary_lock
1634 // The check_constraints/find_class call and update_dictionary sequence
1635 // must be "atomic" for a specific class/classloader pair so we never
1636 // define two different instanceKlasses for that class/classloader pair.
1637 // Existing classloaders will call define_instance_class with the
1638 // classloader lock held
1639 // Parallel classloaders will call find_or_define_instance_class
1640 // which will require a token to perform the define class
1641 Symbol* name_h = k->name();
1642 Dictionary* dictionary = loader_data->dictionary();
1643 unsigned int d_hash = dictionary->compute_hash(name_h);
1644 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1645
1646 // Register class just loaded with class loader (placed in Vector)
1647 // Note we do this before updating the dictionary, as this can
1648 // fail with an OutOfMemoryError (if it does, we will *not* put this
1649 // class in the dictionary and will not update the class hierarchy).
1650 // JVMTI FollowReferences needs to find the classes this way.
1651 if (k->class_loader() != NULL) {
1652 methodHandle m(THREAD, Universe::loader_addClass_method());
1653 JavaValue result(T_VOID);
1654 JavaCallArguments args(class_loader_h);
1655 args.push_oop(Handle(THREAD, k->java_mirror()));
1656 JavaCalls::call(&result, m, &args, CHECK);
1657 }
1658
1659 // Add the new class. We need recompile lock during update of CHA.
1660 {
1661 unsigned int p_hash = placeholders()->compute_hash(name_h);
1662 int p_index = placeholders()->hash_to_index(p_hash);
1663
1664 MutexLocker mu_r(Compile_lock, THREAD);
1665
1666 // Add to class hierarchy, initialize vtables, and do possible
1667 // deoptimizations.
1668 add_to_hierarchy(k, CHECK); // No exception, but can block
1669
1670 // Add to systemDictionary - so other classes can see it.
1671 // Grabs and releases SystemDictionary_lock
1672 update_dictionary(d_hash, p_index, p_hash,
1673 k, class_loader_h, THREAD);
1674 }
1675 k->eager_initialize(THREAD);
1676
1677 // notify jvmti
1678 if (JvmtiExport::should_post_class_load()) {
1679 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1680 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1681
1682 }
1683 class_define_event(k, loader_data);
1684 }
1685
1686 // Support parallel classloading
1687 // All parallel class loaders, including bootstrap classloader
1688 // lock a placeholder entry for this class/class_loader pair
1689 // to allow parallel defines of different classes for this class loader
1690 // With AllowParallelDefine flag==true, in case they do not synchronize around
1691 // FindLoadedClass/DefineClass, calls, we check for parallel
1692 // loading for them, wait if a defineClass is in progress
1693 // and return the initial requestor's results
1694 // This flag does not apply to the bootstrap classloader.
1695 // With AllowParallelDefine flag==false, call through to define_instance_class
1696 // which will throw LinkageError: duplicate class definition.
1697 // False is the requested default.
1698 // For better performance, the class loaders should synchronize
1699 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1700 // potentially waste time reading and parsing the bytestream.
1701 // Note: VM callers should ensure consistency of k/class_name,class_loader
1702 // Be careful when modifying this code: once you have run
1703 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1704 // you need to find_and_remove it before returning.
1705 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1706 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1707 InstanceKlass* k, TRAPS) {
1708
1709 Symbol* name_h = k->name(); // passed in class_name may be null
1710 ClassLoaderData* loader_data = class_loader_data(class_loader);
1711 Dictionary* dictionary = loader_data->dictionary();
1712
1713 unsigned int d_hash = dictionary->compute_hash(name_h);
1714
1715 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1716 unsigned int p_hash = placeholders()->compute_hash(name_h);
1717 int p_index = placeholders()->hash_to_index(p_hash);
1718 PlaceholderEntry* probe;
1719
1720 {
1721 MutexLocker mu(SystemDictionary_lock, THREAD);
1722 // First check if class already defined
1723 if (is_parallelDefine(class_loader)) {
1724 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1725 if (check != NULL) {
1726 return check;
1727 }
1728 }
1729
1730 // Acquire define token for this class/classloader
1731 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1732 // Wait if another thread defining in parallel
1733 // All threads wait - even those that will throw duplicate class: otherwise
1734 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1735 // if other thread has not finished updating dictionary
1736 while (probe->definer() != NULL) {
1737 SystemDictionary_lock->wait();
1738 }
1739 // Only special cases allow parallel defines and can use other thread's results
1740 // Other cases fall through, and may run into duplicate defines
1741 // caught by finding an entry in the SystemDictionary
1742 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1743 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1744 SystemDictionary_lock->notify_all();
1745 #ifdef ASSERT
1746 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1747 assert(check != NULL, "definer missed recording success");
1748 #endif
1749 return probe->instance_klass();
1750 } else {
1751 // This thread will define the class (even if earlier thread tried and had an error)
1752 probe->set_definer(THREAD);
1753 }
1754 }
1755
1756 define_instance_class(k, THREAD);
1757
1758 Handle linkage_exception = Handle(); // null handle
1759
1760 // definer must notify any waiting threads
1761 {
1762 MutexLocker mu(SystemDictionary_lock, THREAD);
1763 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1764 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1765 if (probe != NULL) {
1766 if (HAS_PENDING_EXCEPTION) {
1767 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1768 CLEAR_PENDING_EXCEPTION;
1769 } else {
1770 probe->set_instance_klass(k);
1771 }
1772 probe->set_definer(NULL);
1773 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1774 SystemDictionary_lock->notify_all();
1775 }
1776 }
1777
1778 // Can't throw exception while holding lock due to rank ordering
1779 if (linkage_exception() != NULL) {
1780 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1781 }
1782
1783 return k;
1784 }
1785
1786 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1787 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1788 if (class_loader.is_null()) {
1789 return Handle(THREAD, _system_loader_lock_obj);
1790 } else {
1791 return class_loader;
1792 }
1793 }
1794
1795 // This method is added to check how often we have to wait to grab loader
1796 // lock. The results are being recorded in the performance counters defined in
1797 // ClassLoader::_sync_systemLoaderLockContentionRate and
1798 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1799 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1800 if (!UsePerfData) {
1801 return;
1802 }
1803
1804 assert(!loader_lock.is_null(), "NULL lock object");
1805
1806 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1807 == ObjectSynchronizer::owner_other) {
1808 // contention will likely happen, so increment the corresponding
1809 // contention counter.
1810 if (loader_lock() == _system_loader_lock_obj) {
1811 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1812 } else {
1813 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1814 }
1815 }
1816 }
1817
1818 // ----------------------------------------------------------------------------
1819 // Lookup
1820
1821 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1822 Symbol* class_name,
1823 Dictionary* dictionary) {
1824 assert_locked_or_safepoint(SystemDictionary_lock);
1825 int index = dictionary->hash_to_index(hash);
1826 return dictionary->find_class(index, hash, class_name);
1827 }
1828
1829
1830 // Basic find on classes in the midst of being loaded
1831 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1832 ClassLoaderData* loader_data) {
1833 assert_locked_or_safepoint(SystemDictionary_lock);
1834 unsigned int p_hash = placeholders()->compute_hash(class_name);
1835 int p_index = placeholders()->hash_to_index(p_hash);
1836 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1837 }
1838
1839
1840 // Used for assertions and verification only
1841 // Precalculating the hash and index is an optimization because there are many lookups
1842 // before adding the class.
1843 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1844 assert_locked_or_safepoint(SystemDictionary_lock);
1845 #ifndef ASSERT
1846 guarantee(VerifyBeforeGC ||
1847 VerifyDuringGC ||
1848 VerifyBeforeExit ||
1849 VerifyDuringStartup ||
1850 VerifyAfterGC, "too expensive");
1851 #endif
1852
1853 Dictionary* dictionary = loader_data->dictionary();
1854 unsigned int d_hash = dictionary->compute_hash(class_name);
1855 return find_class(d_hash, class_name, dictionary);
1856 }
1857
1858
1859 // ----------------------------------------------------------------------------
1860 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1861 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1862 // before a new class is used.
1863
1864 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1865 assert(k != NULL, "just checking");
1866 assert_locked_or_safepoint(Compile_lock);
1867
1868 // Link into hierachy. Make sure the vtables are initialized before linking into
1869 k->append_to_sibling_list(); // add to superklass/sibling list
1870 k->process_interfaces(THREAD); // handle all "implements" declarations
1871 k->set_init_state(InstanceKlass::loaded);
1872 // Now flush all code that depended on old class hierarchy.
1873 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1874 // Also, first reinitialize vtable because it may have gotten out of synch
1875 // while the new class wasn't connected to the class hierarchy.
1876 CodeCache::flush_dependents_on(k);
1877 }
1878
1879 // ----------------------------------------------------------------------------
1880 // GC support
1881
1882 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1883 roots_oops_do(blk, NULL);
1884 }
1885
1886
1887 #ifdef ASSERT
1888 class VerifySDReachableAndLiveClosure : public OopClosure {
1889 private:
1890 BoolObjectClosure* _is_alive;
1891
1892 template <class T> void do_oop_work(T* p) {
1893 oop obj = oopDesc::load_decode_heap_oop(p);
1894 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1895 }
1896
1897 public:
1898 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1899
1900 virtual void do_oop(oop* p) { do_oop_work(p); }
1901 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1902 };
1903 #endif
1904
1905 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1906 // Note: anonymous classes are not in the SD.
1907 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1908 GCTimer* gc_timer,
1909 bool do_cleaning) {
1910
1911
1912 bool unloading_occurred;
1913 {
1914 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1915
1916 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1917 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1918 do_cleaning);
1919 }
1920
1921 if (unloading_occurred) {
1922 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1923 constraints()->purge_loader_constraints();
1924 resolution_errors()->purge_resolution_errors();
1925 }
1926
1927 {
1928 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1929 // Oops referenced by the protection domain cache table may get unreachable independently
1930 // of the class loader (eg. cached protection domain oops). So we need to
1931 // explicitly unlink them here.
1932 _pd_cache_table->unlink(is_alive);
1933
1934 #ifdef ASSERT
1935 VerifySDReachableAndLiveClosure cl(is_alive);
1936 _pd_cache_table->oops_do(&cl);
1937 #endif
1938 }
1939
1940 if (do_cleaning) {
1941 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1942 ResolvedMethodTable::unlink(is_alive);
1943 }
1944
1945 return unloading_occurred;
1946 }
1947
1948 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1949 strong->do_oop(&_java_system_loader);
1950 strong->do_oop(&_java_platform_loader);
1951 strong->do_oop(&_system_loader_lock_obj);
1952 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1953
1954 // Do strong roots marking if the closures are the same.
1955 if (strong == weak || !ClassUnloading) {
1956 // Only the protection domain oops contain references into the heap. Iterate
1957 // over all of them.
1958 _pd_cache_table->oops_do(strong);
1959 } else {
1960 if (weak != NULL) {
1961 _pd_cache_table->oops_do(weak);
1962 }
1963 }
1964
1965 // Visit extra methods
1966 invoke_method_table()->oops_do(strong);
1967
1968 if (weak != NULL) {
1969 ResolvedMethodTable::oops_do(weak);
1970 }
1971 }
1972
1973 void SystemDictionary::oops_do(OopClosure* f) {
1974 f->do_oop(&_java_system_loader);
1975 f->do_oop(&_java_platform_loader);
1976 f->do_oop(&_system_loader_lock_obj);
1977 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1978
1979 // Only the protection domain oops contain references into the heap. Iterate
1980 // over all of them.
1981 _pd_cache_table->oops_do(f);
1982
1983 // Visit extra methods
1984 invoke_method_table()->oops_do(f);
1985
1986 ResolvedMethodTable::oops_do(f);
1987 }
1988
1989 // CDS: scan and relocate all classes in the system dictionary.
1990 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1991 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1992 }
1993
1994 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1995 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1996 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1997 it->push(well_known_klass_addr((WKID)id));
1998 }
1999 }
2000
2001 void SystemDictionary::methods_do(void f(Method*)) {
2002 // Walk methods in loaded classes
2003 ClassLoaderDataGraph::methods_do(f);
2004 // Walk method handle intrinsics
2005 invoke_method_table()->methods_do(f);
2006 }
2007
2008 class RemoveClassesClosure : public CLDClosure {
2009 public:
2010 void do_cld(ClassLoaderData* cld) {
2011 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2012 cld->dictionary()->remove_classes_in_error_state();
2013 }
2014 }
2015 };
2016
2017 void SystemDictionary::remove_classes_in_error_state() {
2018 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
2019 RemoveClassesClosure rcc;
2020 ClassLoaderDataGraph::cld_do(&rcc);
2021 }
2022
2023 // ----------------------------------------------------------------------------
2024 // Lazily load klasses
2025
2026 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2027 // if multiple threads calling this function, only one thread will load
2028 // the class. The other threads will find the loaded version once the
2029 // class is loaded.
2030 Klass* aos = _abstract_ownable_synchronizer_klass;
2031 if (aos == NULL) {
2032 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2033 // Force a fence to prevent any read before the write completes
2034 OrderAccess::fence();
2035 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2036 }
2037 }
2038
2039 // ----------------------------------------------------------------------------
2040 // Initialization
2041
2042 void SystemDictionary::initialize(TRAPS) {
2043 // Allocate arrays
2044 _placeholders = new PlaceholderTable(_placeholder_table_size);
2045 _number_of_modifications = 0;
2046 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2047 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2048 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2049 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2050
2051 // Allocate private object used as system class loader lock
2052 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2053 // Initialize basic classes
2054 initialize_preloaded_classes(CHECK);
2055 }
2056
2057 // Compact table of directions on the initialization of klasses:
2058 static const short wk_init_info[] = {
2059 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2060 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2061 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2062 | (int)SystemDictionary::option ),
2063 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2064 #undef WK_KLASS_INIT_INFO
2065 0
2066 };
2067
2068 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2069 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2070 int info = wk_init_info[id - FIRST_WKID];
2071 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2072 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2073 InstanceKlass** klassp = &_well_known_klasses[id];
2074
2075 bool must_load;
2076 #if INCLUDE_JVMCI
2077 if (EnableJVMCI) {
2078 // If JVMCI is enabled we require its classes to be found.
2079 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2080 } else
2081 #endif
2082 {
2083 must_load = (init_opt < SystemDictionary::Opt);
2084 }
2085
2086 if (init_opt == SystemDictionary::ValhallaClasses) {
2087 if (EnableValhalla) {
2088 must_load = true;
2089 } else {
2090 return false;
2091 }
2092 }
2093
2094 if ((*klassp) == NULL) {
2095 Klass* k;
2096 if (must_load) {
2097 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2098 } else {
2099 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2100 }
2101 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2102 }
2103 return ((*klassp) != NULL);
2104 }
2105
2106 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2107 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2108 for (int id = (int)start_id; id < (int)limit_id; id++) {
2109 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2110 int info = wk_init_info[id - FIRST_WKID];
2111 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2112 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2113
2114 initialize_wk_klass((WKID)id, opt, CHECK);
2115 }
2116
2117 // move the starting value forward to the limit:
2118 start_id = limit_id;
2119 }
2120
2121 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2122 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2123
2124 // Create the ModuleEntry for java.base. This call needs to be done here,
2125 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2126 ClassLoader::classLoader_init2(CHECK);
2127
2128 // Preload commonly used klasses
2129 WKID scan = FIRST_WKID;
2130 // first do Object, then String, Class
2131 #if INCLUDE_CDS
2132 if (UseSharedSpaces) {
2133 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2134 // Initialize the constant pool for the Object_class
2135 Object_klass()->constants()->restore_unshareable_info(CHECK);
2136 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2137 } else
2138 #endif
2139 {
2140 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2141 }
2142
2143 // Calculate offsets for String and Class classes since they are loaded and
2144 // can be used after this point.
2145 java_lang_String::compute_offsets();
2146 java_lang_Class::compute_offsets();
2147
2148 // Fixup mirrors for classes loaded before java.lang.Class.
2149 // These calls iterate over the objects currently in the perm gen
2150 // so calling them at this point is matters (not before when there
2151 // are fewer objects and not later after there are more objects
2152 // in the perm gen.
2153 Universe::initialize_basic_type_mirrors(CHECK);
2154 Universe::fixup_mirrors(CHECK);
2155
2156 // do a bunch more:
2157 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2158
2159 // Preload ref klasses and set reference types
2160 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2161 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2162
2163 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2164 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2165 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2166 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2167 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2168
2169 // JSR 292 classes
2170 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2171 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2172 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2173 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2174 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2175
2176 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2177 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2178 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2179 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2180 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2181 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2182 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2183 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2184 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2185 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2186
2187 { // Compute whether we should use checkPackageAccess or NOT
2188 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2189 _has_checkPackageAccess = (method != NULL);
2190 }
2191 }
2192
2193 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2194 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2195 BasicType SystemDictionary::box_klass_type(Klass* k) {
2196 assert(k != NULL, "");
2197 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2198 if (_box_klasses[i] == k)
2199 return (BasicType)i;
2200 }
2201 return T_OBJECT;
2202 }
2203
2204 // Constraints on class loaders. The details of the algorithm can be
2205 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2206 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2207 // that the dictionary needs to maintain a set of contraints that
2208 // must be satisfied by all classes in the dictionary.
2209 // if defining is true, then LinkageError if already in dictionary
2210 // if initiating loader, then ok if InstanceKlass matches existing entry
2211
2212 void SystemDictionary::check_constraints(unsigned int d_hash,
2213 InstanceKlass* k,
2214 Handle class_loader, bool defining,
2215 TRAPS) {
2216 const char *linkage_error1 = NULL;
2217 const char *linkage_error2 = NULL;
2218 {
2219 Symbol* name = k->name();
2220 ClassLoaderData *loader_data = class_loader_data(class_loader);
2221
2222 MutexLocker mu(SystemDictionary_lock, THREAD);
2223
2224 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2225 if (check != NULL) {
2226 // if different InstanceKlass - duplicate class definition,
2227 // else - ok, class loaded by a different thread in parallel,
2228 // we should only have found it if it was done loading and ok to use
2229 // dictionary only holds instance classes, placeholders
2230 // also holds array classes
2231
2232 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2233 if ((defining == true) || (k != check)) {
2234 linkage_error1 = "loader (instance of ";
2235 linkage_error2 = "): attempted duplicate class definition for name: \"";
2236 } else {
2237 return;
2238 }
2239 }
2240
2241 #ifdef ASSERT
2242 Symbol* ph_check = find_placeholder(name, loader_data);
2243 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2244 #endif
2245
2246 if (linkage_error1 == NULL) {
2247 if (constraints()->check_or_update(k, class_loader, name) == false) {
2248 linkage_error1 = "loader constraint violation: loader (instance of ";
2249 linkage_error2 = ") previously initiated loading for a different type with name \"";
2250 }
2251 }
2252 }
2253
2254 // Throw error now if needed (cannot throw while holding
2255 // SystemDictionary_lock because of rank ordering)
2256
2257 if (linkage_error1) {
2258 ResourceMark rm(THREAD);
2259 const char* class_loader_name = loader_name(class_loader());
2260 char* type_name = k->name()->as_C_string();
2261 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2262 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2263 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2264 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2265 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2266 }
2267 }
2268
2269
2270 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2271 // have been called.
2272 void SystemDictionary::update_dictionary(unsigned int d_hash,
2273 int p_index, unsigned int p_hash,
2274 InstanceKlass* k,
2275 Handle class_loader,
2276 TRAPS) {
2277 // Compile_lock prevents systemDictionary updates during compilations
2278 assert_locked_or_safepoint(Compile_lock);
2279 Symbol* name = k->name();
2280 ClassLoaderData *loader_data = class_loader_data(class_loader);
2281
2282 {
2283 MutexLocker mu1(SystemDictionary_lock, THREAD);
2284
2285 // See whether biased locking is enabled and if so set it for this
2286 // klass.
2287 // Note that this must be done past the last potential blocking
2288 // point / safepoint. We enable biased locking lazily using a
2289 // VM_Operation to iterate the SystemDictionary and installing the
2290 // biasable mark word into each InstanceKlass's prototype header.
2291 // To avoid race conditions where we accidentally miss enabling the
2292 // optimization for one class in the process of being added to the
2293 // dictionary, we must not safepoint after the test of
2294 // BiasedLocking::enabled().
2295 if (UseBiasedLocking && BiasedLocking::enabled()) {
2296 // Set biased locking bit for all loaded classes; it will be
2297 // cleared if revocation occurs too often for this type
2298 // NOTE that we must only do this when the class is initally
2299 // defined, not each time it is referenced from a new class loader
2300 if (k->class_loader() == class_loader() && !k->is_value()) {
2301 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2302 }
2303 }
2304
2305 // Make a new dictionary entry.
2306 Dictionary* dictionary = loader_data->dictionary();
2307 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2308 if (sd_check == NULL) {
2309 dictionary->add_klass(d_hash, name, k);
2310 notice_modification();
2311 }
2312 #ifdef ASSERT
2313 sd_check = find_class(d_hash, name, dictionary);
2314 assert (sd_check != NULL, "should have entry in dictionary");
2315 // Note: there may be a placeholder entry: for circularity testing
2316 // or for parallel defines
2317 #endif
2318 SystemDictionary_lock->notify_all();
2319 }
2320 }
2321
2322
2323 // Try to find a class name using the loader constraints. The
2324 // loader constraints might know about a class that isn't fully loaded
2325 // yet and these will be ignored.
2326 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2327 Symbol* class_name, Handle class_loader, TRAPS) {
2328
2329 // First see if it has been loaded directly.
2330 // Force the protection domain to be null. (This removes protection checks.)
2331 Handle no_protection_domain;
2332 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2333 no_protection_domain, CHECK_NULL);
2334 if (klass != NULL)
2335 return klass;
2336
2337 // Now look to see if it has been loaded elsewhere, and is subject to
2338 // a loader constraint that would require this loader to return the
2339 // klass that is already loaded.
2340 if (FieldType::is_array(class_name)) {
2341 // For array classes, their Klass*s are not kept in the
2342 // constraint table. The element Klass*s are.
2343 FieldArrayInfo fd;
2344 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2345 if (t != T_OBJECT && t != T_VALUETYPE) {
2346 klass = Universe::typeArrayKlassObj(t);
2347 } else {
2348 MutexLocker mu(SystemDictionary_lock, THREAD);
2349 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2350 }
2351 // If element class already loaded, allocate array klass
2352 if (klass != NULL) {
2353 klass = klass->array_klass_or_null(fd.dimension());
2354 }
2355 } else {
2356 MutexLocker mu(SystemDictionary_lock, THREAD);
2357 // Non-array classes are easy: simply check the constraint table.
2358 klass = constraints()->find_constrained_klass(class_name, class_loader);
2359 }
2360
2361 return klass;
2362 }
2363
2364
2365 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2366 Handle class_loader1,
2367 Handle class_loader2,
2368 Thread* THREAD) {
2369 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2370 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2371
2372 Symbol* constraint_name = NULL;
2373 if (!FieldType::is_array(class_name)) {
2374 constraint_name = class_name;
2375 } else {
2376 // For array classes, their Klass*s are not kept in the
2377 // constraint table. The element classes are.
2378 FieldArrayInfo fd;
2379 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2380 // primitive types always pass
2381 if (t != T_OBJECT) {
2382 return true;
2383 } else {
2384 constraint_name = fd.object_key();
2385 }
2386 }
2387
2388 Dictionary* dictionary1 = loader_data1->dictionary();
2389 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2390
2391 Dictionary* dictionary2 = loader_data2->dictionary();
2392 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2393
2394 {
2395 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2396 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2397 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2398 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2399 klass2, class_loader2);
2400 }
2401 }
2402
2403 // Add entry to resolution error table to record the error when the first
2404 // attempt to resolve a reference to a class has failed.
2405 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2406 Symbol* error, Symbol* message) {
2407 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2408 int index = resolution_errors()->hash_to_index(hash);
2409 {
2410 MutexLocker ml(SystemDictionary_lock, Thread::current());
2411 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2412 }
2413 }
2414
2415 // Delete a resolution error for RedefineClasses for a constant pool is going away
2416 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2417 resolution_errors()->delete_entry(pool);
2418 }
2419
2420 // Lookup resolution error table. Returns error if found, otherwise NULL.
2421 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2422 Symbol** message) {
2423 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2424 int index = resolution_errors()->hash_to_index(hash);
2425 {
2426 MutexLocker ml(SystemDictionary_lock, Thread::current());
2427 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2428 if (entry != NULL) {
2429 *message = entry->message();
2430 return entry->error();
2431 } else {
2432 return NULL;
2433 }
2434 }
2435 }
2436
2437
2438 // Signature constraints ensure that callers and callees agree about
2439 // the meaning of type names in their signatures. This routine is the
2440 // intake for constraints. It collects them from several places:
2441 //
2442 // * LinkResolver::resolve_method (if check_access is true) requires
2443 // that the resolving class (the caller) and the defining class of
2444 // the resolved method (the callee) agree on each type in the
2445 // method's signature.
2446 //
2447 // * LinkResolver::resolve_interface_method performs exactly the same
2448 // checks.
2449 //
2450 // * LinkResolver::resolve_field requires that the constant pool
2451 // attempting to link to a field agree with the field's defining
2452 // class about the type of the field signature.
2453 //
2454 // * klassVtable::initialize_vtable requires that, when a class
2455 // overrides a vtable entry allocated by a superclass, that the
2456 // overriding method (i.e., the callee) agree with the superclass
2457 // on each type in the method's signature.
2458 //
2459 // * klassItable::initialize_itable requires that, when a class fills
2460 // in its itables, for each non-abstract method installed in an
2461 // itable, the method (i.e., the callee) agree with the interface
2462 // on each type in the method's signature.
2463 //
2464 // All those methods have a boolean (check_access, checkconstraints)
2465 // which turns off the checks. This is used from specialized contexts
2466 // such as bootstrapping, dumping, and debugging.
2467 //
2468 // No direct constraint is placed between the class and its
2469 // supertypes. Constraints are only placed along linked relations
2470 // between callers and callees. When a method overrides or implements
2471 // an abstract method in a supertype (superclass or interface), the
2472 // constraints are placed as if the supertype were the caller to the
2473 // overriding method. (This works well, since callers to the
2474 // supertype have already established agreement between themselves and
2475 // the supertype.) As a result of all this, a class can disagree with
2476 // its supertype about the meaning of a type name, as long as that
2477 // class neither calls a relevant method of the supertype, nor is
2478 // called (perhaps via an override) from the supertype.
2479 //
2480 //
2481 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2482 //
2483 // Make sure all class components (including arrays) in the given
2484 // signature will be resolved to the same class in both loaders.
2485 // Returns the name of the type that failed a loader constraint check, or
2486 // NULL if no constraint failed. No exception except OOME is thrown.
2487 // Arrays are not added to the loader constraint table, their elements are.
2488 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2489 Handle loader1, Handle loader2,
2490 bool is_method, TRAPS) {
2491 // Nothing to do if loaders are the same.
2492 if (loader1() == loader2()) {
2493 return NULL;
2494 }
2495
2496 SignatureStream sig_strm(signature, is_method);
2497 while (!sig_strm.is_done()) {
2498 if (sig_strm.is_object()) {
2499 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2500 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2501 return sig;
2502 }
2503 }
2504 sig_strm.next();
2505 }
2506 return NULL;
2507 }
2508
2509
2510 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2511 Symbol* signature,
2512 TRAPS) {
2513 methodHandle empty;
2514 assert(MethodHandles::is_signature_polymorphic(iid) &&
2515 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2516 iid != vmIntrinsics::_invokeGeneric,
2517 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2518
2519 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2520 int index = invoke_method_table()->hash_to_index(hash);
2521 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2522 methodHandle m;
2523 if (spe == NULL || spe->method() == NULL) {
2524 spe = NULL;
2525 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2526 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2527 if (!Arguments::is_interpreter_only()) {
2528 // Generate a compiled form of the MH intrinsic.
2529 AdapterHandlerLibrary::create_native_wrapper(m);
2530 // Check if have the compiled code.
2531 if (!m->has_compiled_code()) {
2532 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2533 "Out of space in CodeCache for method handle intrinsic", empty);
2534 }
2535 }
2536 // Now grab the lock. We might have to throw away the new method,
2537 // if a racing thread has managed to install one at the same time.
2538 {
2539 MutexLocker ml(SystemDictionary_lock, THREAD);
2540 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2541 if (spe == NULL)
2542 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2543 if (spe->method() == NULL)
2544 spe->set_method(m());
2545 }
2546 }
2547
2548 assert(spe != NULL && spe->method() != NULL, "");
2549 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2550 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2551 "MH intrinsic invariant");
2552 return spe->method();
2553 }
2554
2555 // Helper for unpacking the return value from linkMethod and linkCallSite.
2556 static methodHandle unpack_method_and_appendix(Handle mname,
2557 Klass* accessing_klass,
2558 objArrayHandle appendix_box,
2559 Handle* appendix_result,
2560 TRAPS) {
2561 methodHandle empty;
2562 if (mname.not_null()) {
2563 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2564 if (m != NULL) {
2565 oop appendix = appendix_box->obj_at(0);
2566 if (TraceMethodHandles) {
2567 #ifndef PRODUCT
2568 ttyLocker ttyl;
2569 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2570 m->print();
2571 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2572 tty->cr();
2573 #endif //PRODUCT
2574 }
2575 (*appendix_result) = Handle(THREAD, appendix);
2576 // the target is stored in the cpCache and if a reference to this
2577 // MethodName is dropped we need a way to make sure the
2578 // class_loader containing this method is kept alive.
2579 // FIXME: the appendix might also preserve this dependency.
2580 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2581 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2582 return methodHandle(THREAD, m);
2583 }
2584 }
2585 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2586 return empty;
2587 }
2588
2589 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2590 Symbol* name,
2591 Symbol* signature,
2592 Klass* accessing_klass,
2593 Handle *appendix_result,
2594 Handle *method_type_result,
2595 TRAPS) {
2596 methodHandle empty;
2597 assert(THREAD->can_call_java() ,"");
2598 Handle method_type =
2599 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2600
2601 int ref_kind = JVM_REF_invokeVirtual;
2602 oop name_oop = StringTable::intern(name, CHECK_(empty));
2603 Handle name_str (THREAD, name_oop);
2604 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2605 assert(appendix_box->obj_at(0) == NULL, "");
2606
2607 // This should not happen. JDK code should take care of that.
2608 if (accessing_klass == NULL || method_type.is_null()) {
2609 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2610 }
2611
2612 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2613 JavaCallArguments args;
2614 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2615 args.push_int(ref_kind);
2616 args.push_oop(Handle(THREAD, klass->java_mirror()));
2617 args.push_oop(name_str);
2618 args.push_oop(method_type);
2619 args.push_oop(appendix_box);
2620 JavaValue result(T_OBJECT);
2621 JavaCalls::call_static(&result,
2622 SystemDictionary::MethodHandleNatives_klass(),
2623 vmSymbols::linkMethod_name(),
2624 vmSymbols::linkMethod_signature(),
2625 &args, CHECK_(empty));
2626 Handle mname(THREAD, (oop) result.get_jobject());
2627 (*method_type_result) = method_type;
2628 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2629 }
2630
2631 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2632 // We must ensure that all class loaders everywhere will reach this class, for any client.
2633 // This is a safe bet for public classes in java.lang, such as Object and String.
2634 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2635 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2636 static bool is_always_visible_class(oop mirror) {
2637 Klass* klass = java_lang_Class::as_Klass(mirror);
2638 if (klass->is_objArray_klass()) {
2639 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2640 }
2641 if (klass->is_typeArray_klass()) {
2642 return true; // primitive array
2643 }
2644 assert(klass->is_instance_klass(), "%s", klass->external_name());
2645 return klass->is_public() &&
2646 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2647 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2648 }
2649
2650
2651 // Return the Java mirror (java.lang.Class instance) for a single-character
2652 // descriptor. This result, when available, is the same as produced by the
2653 // heavier API point of the same name that takes a Symbol.
2654 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2655 return java_lang_Class::primitive_mirror(char2type(signature_char));
2656 }
2657
2658 // Find or construct the Java mirror (java.lang.Class instance) for a
2659 // for the given field type signature, as interpreted relative to the
2660 // given class loader. Handles primitives, void, references, arrays,
2661 // and all other reflectable types, except method types.
2662 // N.B. Code in reflection should use this entry point.
2663 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2664 Klass* accessing_klass,
2665 Handle class_loader,
2666 Handle protection_domain,
2667 SignatureStream::FailureMode failure_mode,
2668 TRAPS) {
2669 Handle empty;
2670
2671 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2672 "one or the other, or perhaps neither");
2673
2674 Symbol* type = signature;
2675
2676 // What we have here must be a valid field descriptor,
2677 // and all valid field descriptors are supported.
2678 // Produce the same java.lang.Class that reflection reports.
2679 if (type->utf8_length() == 1) {
2680
2681 // It's a primitive. (Void has a primitive mirror too.)
2682 char ch = (char) type->byte_at(0);
2683 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2684 return Handle(THREAD, find_java_mirror_for_type(ch));
2685
2686 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2687
2688 // It's a reference type.
2689 if (accessing_klass != NULL) {
2690 class_loader = Handle(THREAD, accessing_klass->class_loader());
2691 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2692 }
2693 Klass* constant_type_klass;
2694 if (failure_mode == SignatureStream::ReturnNull) {
2695 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2696 CHECK_(empty));
2697 } else {
2698 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2699 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2700 throw_error, CHECK_(empty));
2701 }
2702 if (constant_type_klass == NULL) {
2703 return Handle(); // report failure this way
2704 }
2705 Handle mirror(THREAD, constant_type_klass->java_mirror());
2706
2707 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2708 if (accessing_klass != NULL) {
2709 Klass* sel_klass = constant_type_klass;
2710 bool fold_type_to_class = true;
2711 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2712 fold_type_to_class, CHECK_(empty));
2713 }
2714
2715 return mirror;
2716
2717 }
2718
2719 // Fall through to an error.
2720 assert(false, "unsupported mirror syntax");
2721 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2722 }
2723
2724
2725 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2726 // signature, as interpreted relative to the given class loader.
2727 // Because of class loader constraints, all method handle usage must be
2728 // consistent with this loader.
2729 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2730 Klass* accessing_klass,
2731 TRAPS) {
2732 Handle empty;
2733 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2734 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2735 int index = invoke_method_table()->hash_to_index(hash);
2736 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2737 if (spe != NULL && spe->method_type() != NULL) {
2738 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2739 return Handle(THREAD, spe->method_type());
2740 } else if (!THREAD->can_call_java()) {
2741 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2742 return Handle(); // do not attempt from within compiler, unless it was cached
2743 }
2744
2745 Handle class_loader, protection_domain;
2746 if (accessing_klass != NULL) {
2747 class_loader = Handle(THREAD, accessing_klass->class_loader());
2748 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2749 }
2750 bool can_be_cached = true;
2751 int npts = ArgumentCount(signature).size();
2752 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2753 int arg = 0;
2754 Handle rt; // the return type from the signature
2755 ResourceMark rm(THREAD);
2756 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2757 oop mirror = NULL;
2758 if (can_be_cached) {
2759 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2760 mirror = ss.as_java_mirror(Handle(), Handle(),
2761 SignatureStream::ReturnNull, CHECK_(empty));
2762 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2763 // Fall back to accessing_klass context.
2764 can_be_cached = false;
2765 }
2766 }
2767 if (!can_be_cached) {
2768 // Resolve, throwing a real error if it doesn't work.
2769 mirror = ss.as_java_mirror(class_loader, protection_domain,
2770 SignatureStream::NCDFError, CHECK_(empty));
2771 }
2772 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2773 if (ss.at_return_type())
2774 rt = Handle(THREAD, mirror);
2775 else
2776 pts->obj_at_put(arg++, mirror);
2777
2778 // Check accessibility.
2779 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2780 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2781 mirror = NULL; // safety
2782 // Emulate ConstantPool::verify_constant_pool_resolve.
2783 bool fold_type_to_class = true;
2784 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2785 fold_type_to_class, CHECK_(empty));
2786 }
2787 }
2788 assert(arg == npts, "");
2789
2790 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2791 JavaCallArguments args(Handle(THREAD, rt()));
2792 args.push_oop(pts);
2793 JavaValue result(T_OBJECT);
2794 JavaCalls::call_static(&result,
2795 SystemDictionary::MethodHandleNatives_klass(),
2796 vmSymbols::findMethodHandleType_name(),
2797 vmSymbols::findMethodHandleType_signature(),
2798 &args, CHECK_(empty));
2799 Handle method_type(THREAD, (oop) result.get_jobject());
2800
2801 if (can_be_cached) {
2802 // We can cache this MethodType inside the JVM.
2803 MutexLocker ml(SystemDictionary_lock, THREAD);
2804 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2805 if (spe == NULL)
2806 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2807 if (spe->method_type() == NULL) {
2808 spe->set_method_type(method_type());
2809 }
2810 }
2811
2812 // report back to the caller with the MethodType
2813 return method_type;
2814 }
2815
2816 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2817 Klass* accessing_klass,
2818 TRAPS) {
2819 Handle empty;
2820 ResourceMark rm(THREAD);
2821 SignatureStream ss(signature, /*is_method=*/ false);
2822 if (!ss.is_done()) {
2823 Handle class_loader, protection_domain;
2824 if (accessing_klass != NULL) {
2825 class_loader = Handle(THREAD, accessing_klass->class_loader());
2826 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2827 }
2828 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2829 ss.next();
2830 if (ss.is_done()) {
2831 return Handle(THREAD, mirror);
2832 }
2833 }
2834 return empty;
2835 }
2836
2837 // Ask Java code to find or construct a method handle constant.
2838 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2839 int ref_kind, //e.g., JVM_REF_invokeVirtual
2840 Klass* callee,
2841 Symbol* name,
2842 Symbol* signature,
2843 TRAPS) {
2844 Handle empty;
2845 if (caller == NULL) {
2846 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2847 }
2848 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2849 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2850
2851 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2852 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2853 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2854 java_lang_invoke_MemberName::set_name (mname(), name_str());
2855 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2856 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2857
2858 if (ref_kind == JVM_REF_invokeVirtual &&
2859 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2860 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2861 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2862 // They are public signature polymorphic methods, but require appendix argument
2863 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2864 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2865 } else {
2866 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2867 }
2868
2869 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2870 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2871
2872 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2873 JavaCallArguments args;
2874 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2875 args.push_int(ref_kind);
2876 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2877 args.push_oop(name_str);
2878 args.push_oop(type);
2879 JavaValue result(T_OBJECT);
2880 JavaCalls::call_static(&result,
2881 SystemDictionary::MethodHandleNatives_klass(),
2882 vmSymbols::linkMethodHandleConstant_name(),
2883 vmSymbols::linkMethodHandleConstant_signature(),
2884 &args, CHECK_(empty));
2885 return Handle(THREAD, (oop) result.get_jobject());
2886 }
2887
2888 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2889 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2890 int condy_index,
2891 Handle bootstrap_specifier,
2892 Symbol* name,
2893 Symbol* type,
2894 TRAPS) {
2895 Handle empty;
2896 Handle bsm, info;
2897 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2898 bsm = bootstrap_specifier;
2899 } else {
2900 assert(bootstrap_specifier->is_objArray(), "");
2901 objArrayOop args = (objArrayOop) bootstrap_specifier();
2902 assert(args->length() == 2, "");
2903 bsm = Handle(THREAD, args->obj_at(0));
2904 info = Handle(THREAD, args->obj_at(1));
2905 }
2906 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2907 "caller must supply a valid BSM");
2908
2909 // This should not happen. JDK code should take care of that.
2910 if (caller == NULL) {
2911 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2912 }
2913
2914 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2915
2916 // Resolve the constant type in the context of the caller class
2917 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2918 CHECK_(empty));
2919
2920 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2921 JavaCallArguments args;
2922 args.push_oop(Handle(THREAD, caller->java_mirror()));
2923 args.push_int(condy_index);
2924 args.push_oop(bsm);
2925 args.push_oop(constant_name);
2926 args.push_oop(type_mirror);
2927 args.push_oop(info);
2928 JavaValue result(T_OBJECT);
2929 JavaCalls::call_static(&result,
2930 SystemDictionary::MethodHandleNatives_klass(),
2931 vmSymbols::linkDynamicConstant_name(),
2932 vmSymbols::linkDynamicConstant_signature(),
2933 &args, CHECK_(empty));
2934
2935 return Handle(THREAD, (oop) result.get_jobject());
2936 }
2937
2938 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2939 // name and signature, as interpreted relative to the given class loader.
2940 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2941 int indy_index,
2942 Handle bootstrap_specifier,
2943 Symbol* name,
2944 Symbol* type,
2945 Handle *appendix_result,
2946 Handle *method_type_result,
2947 TRAPS) {
2948 methodHandle empty;
2949 Handle bsm, info;
2950 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2951 bsm = bootstrap_specifier;
2952 } else {
2953 objArrayOop args = (objArrayOop) bootstrap_specifier();
2954 assert(args->length() == 2, "");
2955 bsm = Handle(THREAD, args->obj_at(0));
2956 info = Handle(THREAD, args->obj_at(1));
2957 }
2958 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2959 "caller must supply a valid BSM");
2960
2961 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2962 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2963
2964 // This should not happen. JDK code should take care of that.
2965 if (caller == NULL || method_type.is_null()) {
2966 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2967 }
2968
2969 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2970 assert(appendix_box->obj_at(0) == NULL, "");
2971
2972 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2973 JavaCallArguments args;
2974 args.push_oop(Handle(THREAD, caller->java_mirror()));
2975 args.push_int(indy_index);
2976 args.push_oop(bsm);
2977 args.push_oop(method_name);
2978 args.push_oop(method_type);
2979 args.push_oop(info);
2980 args.push_oop(appendix_box);
2981 JavaValue result(T_OBJECT);
2982 JavaCalls::call_static(&result,
2983 SystemDictionary::MethodHandleNatives_klass(),
2984 vmSymbols::linkCallSite_name(),
2985 vmSymbols::linkCallSite_signature(),
2986 &args, CHECK_(empty));
2987 Handle mname(THREAD, (oop) result.get_jobject());
2988 (*method_type_result) = method_type;
2989 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2990 }
2991
2992 // Protection domain cache table handling
2993
2994 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2995 return _pd_cache_table->get(protection_domain);
2996 }
2997
2998 #if INCLUDE_CDS
2999 void SystemDictionary::reorder_dictionary_for_sharing() {
3000 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
3001 }
3002 #endif
3003
3004 size_t SystemDictionary::count_bytes_for_buckets() {
3005 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
3006 }
3007
3008 size_t SystemDictionary::count_bytes_for_table() {
3009 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
3010 }
3011
3012 void SystemDictionary::copy_buckets(char* top, char* end) {
3013 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
3014 }
3015
3016 void SystemDictionary::copy_table(char* top, char* end) {
3017 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
3018 }
3019
3020 // ----------------------------------------------------------------------------
3021 void SystemDictionary::print_shared(outputStream *st) {
3022 shared_dictionary()->print_on(st);
3023 }
3024
3025 void SystemDictionary::print_on(outputStream *st) {
3026 if (shared_dictionary() != NULL) {
3027 st->print_cr("Shared Dictionary");
3028 shared_dictionary()->print_on(st);
3029 st->cr();
3030 }
3031
3032 GCMutexLocker mu(SystemDictionary_lock);
3033
3034 ClassLoaderDataGraph::print_dictionary(st);
3035
3036 // Placeholders
3037 placeholders()->print_on(st);
3038 st->cr();
3039
3040 // loader constraints - print under SD_lock
3041 constraints()->print_on(st);
3042 st->cr();
3043
3044 _pd_cache_table->print_on(st);
3045 st->cr();
3046 }
3047
3048 void SystemDictionary::verify() {
3049 guarantee(constraints() != NULL,
3050 "Verify of loader constraints failed");
3051 guarantee(placeholders()->number_of_entries() >= 0,
3052 "Verify of placeholders failed");
3053
3054 GCMutexLocker mu(SystemDictionary_lock);
3055
3056 // Verify dictionary
3057 ClassLoaderDataGraph::verify_dictionary();
3058
3059 placeholders()->verify();
3060
3061 // Verify constraint table
3062 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3063 constraints()->verify(placeholders());
3064
3065 _pd_cache_table->verify();
3066 }
3067
3068 void SystemDictionary::dump(outputStream *st, bool verbose) {
3069 assert_locked_or_safepoint(SystemDictionary_lock);
3070 if (verbose) {
3071 print_on(st);
3072 } else {
3073 if (shared_dictionary() != NULL) {
3074 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3075 }
3076 ClassLoaderDataGraph::print_dictionary_statistics(st);
3077 placeholders()->print_table_statistics(st, "Placeholder Table");
3078 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3079 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3080 }
3081 }
3082
3083 // Utility for dumping dictionaries.
3084 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3085 DCmdWithParser(output, heap),
3086 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3087 "BOOLEAN", false, "false") {
3088 _dcmdparser.add_dcmd_option(&_verbose);
3089 }
3090
3091 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3092 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3093 _verbose.value());
3094 VMThread::execute(&dumper);
3095 }
3096
3097 int SystemDictionaryDCmd::num_arguments() {
3098 ResourceMark rm;
3099 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3100 if (dcmd != NULL) {
3101 DCmdMark mark(dcmd);
3102 return dcmd->_dcmdparser.num_arguments();
3103 } else {
3104 return 0;
3105 }
3106 }
3107
3108 class CombineDictionariesClosure : public CLDClosure {
3109 private:
3110 Dictionary* _master_dictionary;
3111 public:
3112 CombineDictionariesClosure(Dictionary* master_dictionary) :
3113 _master_dictionary(master_dictionary) {}
3114 void do_cld(ClassLoaderData* cld) {
3115 ResourceMark rm;
3116 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3117 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3118 Dictionary* curr_dictionary = cld->dictionary();
3119 DictionaryEntry* p = curr_dictionary->bucket(i);
3120 while (p != NULL) {
3121 Symbol* name = p->instance_klass()->name();
3122 unsigned int d_hash = _master_dictionary->compute_hash(name);
3123 int d_index = _master_dictionary->hash_to_index(d_hash);
3124 DictionaryEntry* next = p->next();
3125 if (p->literal()->class_loader_data() != cld) {
3126 // This is an initiating class loader entry; don't use it
3127 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3128 curr_dictionary->free_entry(p);
3129 } else {
3130 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3131 curr_dictionary->unlink_entry(p);
3132 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3133 _master_dictionary->add_entry(d_index, p);
3134 }
3135 p = next;
3136 }
3137 *curr_dictionary->bucket_addr(i) = NULL;
3138 }
3139 }
3140 }
3141 };
3142
3143 // Combining platform and system loader dictionaries into boot loader dictionaries.
3144 // During run time, we only have one shared dictionary.
3145 void SystemDictionary::combine_shared_dictionaries() {
3146 assert(DumpSharedSpaces, "dump time only");
3147 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3148 CombineDictionariesClosure cdc(master_dictionary);
3149 ClassLoaderDataGraph::cld_do(&cdc);
3150
3151 // These tables are no longer valid or necessary. Keeping them around will
3152 // cause SystemDictionary::verify() to fail. Let's empty them.
3153 _placeholders = new PlaceholderTable(_placeholder_table_size);
3154 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3155
3156 NOT_PRODUCT(SystemDictionary::verify());
3157 }
3158
3159 // caller needs ResourceMark
3160 const char* SystemDictionary::loader_name(const oop loader) {
3161 return ((loader) == NULL ? "<bootloader>" :
3162 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3163 }
3164
3165 // caller needs ResourceMark
3166 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3167 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3168 SystemDictionary::loader_name(loader_data->class_loader()));
3169 }