1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/resolutionErrors.hpp"
39 #include "classfile/stringTable.hpp"
40 #include "classfile/systemDictionary.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "code/codeCache.hpp"
43 #include "compiler/compileBroker.hpp"
44 #include "gc/shared/gcLocker.hpp"
45 #include "interpreter/bytecodeStream.hpp"
46 #include "interpreter/interpreter.hpp"
47 #include "memory/filemap.hpp"
48 #include "memory/oopFactory.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/instanceRefKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/methodData.hpp"
54 #include "oops/objArrayKlass.hpp"
55 #include "oops/objArrayOop.inline.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayKlass.hpp"
59 #include "prims/jvmtiEnvBase.hpp"
60 #include "prims/methodHandles.hpp"
61 #include "runtime/arguments.hpp"
62 #include "runtime/biasedLocking.hpp"
63 #include "runtime/fieldType.hpp"
64 #include "runtime/handles.inline.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/mutexLocker.hpp"
68 #include "runtime/orderAccess.inline.hpp"
69 #include "runtime/signature.hpp"
70 #include "services/classLoadingService.hpp"
71 #include "services/threadService.hpp"
72 #include "trace/traceMacros.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/ticks.hpp"
75 #if INCLUDE_CDS
76 #include "classfile/sharedClassUtil.hpp"
77 #include "classfile/systemDictionaryShared.hpp"
78 #endif
79 #if INCLUDE_JVMCI
80 #include "jvmci/jvmciRuntime.hpp"
81 #endif
82 #if INCLUDE_TRACE
83 #include "trace/tracing.hpp"
84 #endif
85
86 Dictionary* SystemDictionary::_dictionary = NULL;
87 PlaceholderTable* SystemDictionary::_placeholders = NULL;
88 Dictionary* SystemDictionary::_shared_dictionary = NULL;
89 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
90 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
91 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
92
93
94 int SystemDictionary::_number_of_modifications = 0;
95 int SystemDictionary::_sdgeneration = 0;
96 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
97 20201,40423,99991};
98
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107
108 bool SystemDictionary::_has_loadClassInternal = false;
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114
115 // ----------------------------------------------------------------------------
116 // Java-level SystemLoader
117
118 oop SystemDictionary::java_system_loader() {
119 return _java_system_loader;
120 }
121
122 void SystemDictionary::compute_java_system_loader(TRAPS) {
123 Klass* system_klass = WK_KLASS(ClassLoader_klass);
124 JavaValue result(T_OBJECT);
125 JavaCalls::call_static(&result,
126 WK_KLASS(ClassLoader_klass),
127 vmSymbols::getSystemClassLoader_name(),
128 vmSymbols::void_classloader_signature(),
129 CHECK);
130
131 _java_system_loader = (oop)result.get_jobject();
132
133 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
134 }
135
136
137 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
138 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
139 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
140 }
141
142 // ----------------------------------------------------------------------------
143 // Parallel class loading check
144
145 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
146 if (UnsyncloadClass || class_loader.is_null()) return true;
147 if (AlwaysLockClassLoader) return false;
148 return java_lang_ClassLoader::parallelCapable(class_loader());
149 }
150 // ----------------------------------------------------------------------------
151 // ParallelDefineClass flag does not apply to bootclass loader
152 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
153 if (class_loader.is_null()) return false;
154 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
155 return true;
156 }
157 return false;
158 }
159
160 // Returns true if the passed class loader is the builtin application class loader
161 // or a custom system class loader. A customer system class loader can be
162 // specified via -Djava.system.class.loader.
163 bool SystemDictionary::is_system_class_loader(oop class_loader) {
164 if (class_loader == NULL) {
165 return false;
166 }
167 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
168 class_loader == _java_system_loader);
169 }
170
171 // Returns true if the passed class loader is the platform class loader.
172 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
173 if (class_loader == NULL) {
174 return false;
175 }
176 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
177 }
178
179 // ----------------------------------------------------------------------------
180 // Resolving of classes
181
182 // Forwards to resolve_or_null
183
184 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
185 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
186 if (HAS_PENDING_EXCEPTION || klass == NULL) {
187 // can return a null klass
188 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
189 }
190 return klass;
191 }
192
193 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
194 bool throw_error,
195 Klass* klass, TRAPS) {
196 if (HAS_PENDING_EXCEPTION) {
197 // If we have a pending exception we forward it to the caller, unless throw_error is true,
198 // in which case we have to check whether the pending exception is a ClassNotFoundException,
199 // and if so convert it to a NoClassDefFoundError
200 // And chain the original ClassNotFoundException
201 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
202 ResourceMark rm(THREAD);
203 assert(klass == NULL, "Should not have result with exception pending");
204 Handle e(THREAD, PENDING_EXCEPTION);
205 CLEAR_PENDING_EXCEPTION;
206 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
207 } else {
208 return NULL;
209 }
210 }
211 // Class not found, throw appropriate error or exception depending on value of throw_error
212 if (klass == NULL) {
213 ResourceMark rm(THREAD);
214 if (throw_error) {
215 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
216 } else {
217 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
218 }
219 }
220 return klass;
221 }
222
223
224 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
225 bool throw_error, TRAPS)
226 {
227 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
228 }
229
230
231 // Forwards to resolve_instance_class_or_null
232
233 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
234 assert(THREAD->can_call_java(),
235 "can not load classes with compiler thread: class=%s, classloader=%s",
236 class_name->as_C_string(),
237 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
238 if (FieldType::is_array(class_name)) {
239 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
240 } else if (FieldType::is_obj(class_name)) {
241 ResourceMark rm(THREAD);
242 // Ignore wrapping L and ;.
243 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
244 class_name->utf8_length() - 2, CHECK_NULL);
245 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
246 } else {
247 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
248 }
249 }
250
251 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
252 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
253 }
254
255 // Forwards to resolve_instance_class_or_null
256
257 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
258 Handle class_loader,
259 Handle protection_domain,
260 TRAPS) {
261 assert(FieldType::is_array(class_name), "must be array");
262 Klass* k = NULL;
263 FieldArrayInfo fd;
264 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
265 // of this call
266 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
267 if (t == T_OBJECT) {
268 // naked oop "k" is OK here -- we assign back into it
269 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
270 class_loader,
271 protection_domain,
272 CHECK_NULL);
273 if (k != NULL) {
274 k = k->array_klass(fd.dimension(), CHECK_NULL);
275 }
276 } else {
277 k = Universe::typeArrayKlassObj(t);
278 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
279 }
280 return k;
281 }
282
283
284 // Must be called for any super-class or super-interface resolution
285 // during class definition to allow class circularity checking
286 // super-interface callers:
287 // parse_interfaces - for defineClass & jvmtiRedefineClasses
288 // super-class callers:
289 // ClassFileParser - for defineClass & jvmtiRedefineClasses
290 // load_shared_class - while loading a class from shared archive
291 // resolve_instance_class_or_null:
292 // via: handle_parallel_super_load
293 // when resolving a class that has an existing placeholder with
294 // a saved superclass [i.e. a defineClass is currently in progress]
295 // if another thread is trying to resolve the class, it must do
296 // super-class checks on its own thread to catch class circularity
297 // This last call is critical in class circularity checking for cases
298 // where classloading is delegated to different threads and the
299 // classloader lock is released.
300 // Take the case: Base->Super->Base
301 // 1. If thread T1 tries to do a defineClass of class Base
302 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
303 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
304 // so it tries to load Super
305 // 3. If we load the class internally, or user classloader uses same thread
306 // loadClassFromxxx or defineClass via parseClassFile Super ...
307 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
308 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
309 // 3.4 calls resolve_super_or_fail Base
310 // 3.5 finds T1,Base -> throws class circularity
311 //OR 4. If T2 tries to resolve Super via defineClass Super ...
312 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
313 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
314 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
315 // 4.4 finds T2, Super -> throws class circularity
316 // Must be called, even if superclass is null, since this is
317 // where the placeholder entry is created which claims this
318 // thread is loading this class/classloader.
319 // Be careful when modifying this code: once you have run
320 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
321 // you need to find_and_remove it before returning.
322 // So be careful to not exit with a CHECK_ macro betweeen these calls.
323 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
324 Symbol* class_name,
325 Handle class_loader,
326 Handle protection_domain,
327 bool is_superclass,
328 TRAPS) {
329 #if INCLUDE_CDS
330 if (DumpSharedSpaces) {
331 // Special processing for CDS dump time.
332 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
333 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
334 if (k) {
335 return k;
336 }
337 }
338 #endif // INCLUDE_CDS
339
340 // Double-check, if child class is already loaded, just return super-class,interface
341 // Don't add a placedholder if already loaded, i.e. already in system dictionary
342 // Make sure there's a placeholder for the *child* before resolving.
343 // Used as a claim that this thread is currently loading superclass/classloader
344 // Used here for ClassCircularity checks and also for heap verification
345 // (every InstanceKlass in the heap needs to be in the system dictionary
346 // or have a placeholder).
347 // Must check ClassCircularity before checking if super class is already loaded
348 //
349 // We might not already have a placeholder if this child_name was
350 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
351 // the name of the class might not be known until the stream is actually
352 // parsed.
353 // Bugs 4643874, 4715493
354 // compute_hash can have a safepoint
355
356 ClassLoaderData* loader_data = class_loader_data(class_loader);
357 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
358 int d_index = dictionary()->hash_to_index(d_hash);
359 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
360 int p_index = placeholders()->hash_to_index(p_hash);
361 // can't throw error holding a lock
362 bool child_already_loaded = false;
363 bool throw_circularity_error = false;
364 {
365 MutexLocker mu(SystemDictionary_lock, THREAD);
366 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
367 Klass* quicksuperk;
368 // to support // loading: if child done loading, just return superclass
369 // if class_name, & class_loader don't match:
370 // if initial define, SD update will give LinkageError
371 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
372 // so we don't throw an exception here.
373 // see: nsk redefclass014 & java.lang.instrument Instrument032
374 if ((childk != NULL ) && (is_superclass) &&
375 ((quicksuperk = childk->super()) != NULL) &&
376
377 ((quicksuperk->name() == class_name) &&
378 (quicksuperk->class_loader() == class_loader()))) {
379 return quicksuperk;
380 } else {
381 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
382 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
383 throw_circularity_error = true;
384 }
385 }
386 if (!throw_circularity_error) {
387 // Be careful not to exit resolve_super
388 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
389 }
390 }
391 if (throw_circularity_error) {
392 ResourceMark rm(THREAD);
393 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
394 }
395
396 // java.lang.Object should have been found above
397 assert(class_name != NULL, "null super class for resolving");
398 // Resolve the super class or interface, check results on return
399 Klass* superk = SystemDictionary::resolve_or_null(class_name,
400 class_loader,
401 protection_domain,
402 THREAD);
403
404 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
405 // It is no longer necessary to keep the placeholder table alive until update_dictionary
406 // or error. GC used to walk the placeholder table as strong roots.
407 // The instanceKlass is kept alive because the class loader is on the stack,
408 // which keeps the loader_data alive, as well as all instanceKlasses in
409 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
410 {
411 MutexLocker mu(SystemDictionary_lock, THREAD);
412 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
413 SystemDictionary_lock->notify_all();
414 }
415 if (HAS_PENDING_EXCEPTION || superk == NULL) {
416 // can null superk
417 superk = handle_resolution_exception(class_name, true, superk, THREAD);
418 }
419
420 return superk;
421 }
422
423 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
424 Handle class_loader,
425 Handle protection_domain,
426 TRAPS) {
427 if(!has_checkPackageAccess()) return;
428
429 // Now we have to call back to java to check if the initating class has access
430 JavaValue result(T_VOID);
431 if (log_is_enabled(Debug, protectiondomain)) {
432 ResourceMark rm;
433 // Print out trace information
434 outputStream* log = Log(protectiondomain)::debug_stream();
435 log->print_cr("Checking package access");
436 log->print("class loader: "); class_loader()->print_value_on(log);
437 log->print(" protection domain: "); protection_domain()->print_value_on(log);
438 log->print(" loading: "); klass->print_value_on(log);
439 log->cr();
440 }
441
442 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
443 JavaCalls::call_special(&result,
444 class_loader,
445 system_loader,
446 vmSymbols::checkPackageAccess_name(),
447 vmSymbols::class_protectiondomain_signature(),
448 Handle(THREAD, klass->java_mirror()),
449 protection_domain,
450 THREAD);
451
452 if (HAS_PENDING_EXCEPTION) {
453 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
454 } else {
455 log_debug(protectiondomain)("granted");
456 }
457
458 if (HAS_PENDING_EXCEPTION) return;
459
460 // If no exception has been thrown, we have validated the protection domain
461 // Insert the protection domain of the initiating class into the set.
462 {
463 // We recalculate the entry here -- we've called out to java since
464 // the last time it was calculated.
465 ClassLoaderData* loader_data = class_loader_data(class_loader);
466
467 Symbol* kn = klass->name();
468 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
469 int d_index = dictionary()->hash_to_index(d_hash);
470
471 MutexLocker mu(SystemDictionary_lock, THREAD);
472 {
473 // Note that we have an entry, and entries can be deleted only during GC,
474 // so we cannot allow GC to occur while we're holding this entry.
475
476 // We're using a NoSafepointVerifier to catch any place where we
477 // might potentially do a GC at all.
478 // Dictionary::do_unloading() asserts that classes in SD are only
479 // unloaded at a safepoint. Anonymous classes are not in SD.
480 NoSafepointVerifier nosafepoint;
481 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
482 protection_domain, THREAD);
483 }
484 }
485 }
486
487 // We only get here if this thread finds that another thread
488 // has already claimed the placeholder token for the current operation,
489 // but that other thread either never owned or gave up the
490 // object lock
491 // Waits on SystemDictionary_lock to indicate placeholder table updated
492 // On return, caller must recheck placeholder table state
493 //
494 // We only get here if
495 // 1) custom classLoader, i.e. not bootstrap classloader
496 // 2) UnsyncloadClass not set
497 // 3) custom classLoader has broken the class loader objectLock
498 // so another thread got here in parallel
499 //
500 // lockObject must be held.
501 // Complicated dance due to lock ordering:
502 // Must first release the classloader object lock to
503 // allow initial definer to complete the class definition
504 // and to avoid deadlock
505 // Reclaim classloader lock object with same original recursion count
506 // Must release SystemDictionary_lock after notify, since
507 // class loader lock must be claimed before SystemDictionary_lock
508 // to prevent deadlocks
509 //
510 // The notify allows applications that did an untimed wait() on
511 // the classloader object lock to not hang.
512 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
513 assert_lock_strong(SystemDictionary_lock);
514
515 bool calledholdinglock
516 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
517 assert(calledholdinglock,"must hold lock for notify");
518 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
519 ObjectSynchronizer::notifyall(lockObject, THREAD);
520 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
521 SystemDictionary_lock->wait();
522 SystemDictionary_lock->unlock();
523 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
524 SystemDictionary_lock->lock();
525 }
526
527 // If the class in is in the placeholder table, class loading is in progress
528 // For cases where the application changes threads to load classes, it
529 // is critical to ClassCircularity detection that we try loading
530 // the superclass on the same thread internally, so we do parallel
531 // super class loading here.
532 // This also is critical in cases where the original thread gets stalled
533 // even in non-circularity situations.
534 // Note: must call resolve_super_or_fail even if null super -
535 // to force placeholder entry creation for this class for circularity detection
536 // Caller must check for pending exception
537 // Returns non-null Klass* if other thread has completed load
538 // and we are done,
539 // If return null Klass* and no pending exception, the caller must load the class
540 InstanceKlass* SystemDictionary::handle_parallel_super_load(
541 Symbol* name, Symbol* superclassname, Handle class_loader,
542 Handle protection_domain, Handle lockObject, TRAPS) {
543
544 ClassLoaderData* loader_data = class_loader_data(class_loader);
545 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
546 int d_index = dictionary()->hash_to_index(d_hash);
547 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
548 int p_index = placeholders()->hash_to_index(p_hash);
549
550 // superk is not used, resolve_super called for circularity check only
551 // This code is reached in two situations. One if this thread
552 // is loading the same class twice (e.g. ClassCircularity, or
553 // java.lang.instrument).
554 // The second is if another thread started the resolve_super first
555 // and has not yet finished.
556 // In both cases the original caller will clean up the placeholder
557 // entry on error.
558 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
559 superclassname,
560 class_loader,
561 protection_domain,
562 true,
563 CHECK_NULL);
564
565 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
566 // Serial class loaders and bootstrap classloader do wait for superclass loads
567 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
568 MutexLocker mu(SystemDictionary_lock, THREAD);
569 // Check if classloading completed while we were loading superclass or waiting
570 return find_class(d_index, d_hash, name, loader_data);
571 }
572
573 // must loop to both handle other placeholder updates
574 // and spurious notifications
575 bool super_load_in_progress = true;
576 PlaceholderEntry* placeholder;
577 while (super_load_in_progress) {
578 MutexLocker mu(SystemDictionary_lock, THREAD);
579 // Check if classloading completed while we were loading superclass or waiting
580 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
581 if (check != NULL) {
582 // Klass is already loaded, so just return it
583 return check;
584 } else {
585 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
586 if (placeholder && placeholder->super_load_in_progress() ){
587 // Before UnsyncloadClass:
588 // We only get here if the application has released the
589 // classloader lock when another thread was in the middle of loading a
590 // superclass/superinterface for this class, and now
591 // this thread is also trying to load this class.
592 // To minimize surprises, the first thread that started to
593 // load a class should be the one to complete the loading
594 // with the classfile it initially expected.
595 // This logic has the current thread wait once it has done
596 // all the superclass/superinterface loading it can, until
597 // the original thread completes the class loading or fails
598 // If it completes we will use the resulting InstanceKlass
599 // which we will find below in the systemDictionary.
600 // We also get here for parallel bootstrap classloader
601 if (class_loader.is_null()) {
602 SystemDictionary_lock->wait();
603 } else {
604 double_lock_wait(lockObject, THREAD);
605 }
606 } else {
607 // If not in SD and not in PH, other thread's load must have failed
608 super_load_in_progress = false;
609 }
610 }
611 }
612 return NULL;
613 }
614
615 static void post_class_load_event(const Ticks& start_time,
616 InstanceKlass* k,
617 const ClassLoaderData* init_cld) {
618 #if INCLUDE_TRACE
619 EventClassLoad event(UNTIMED);
620 if (event.should_commit()) {
621 event.set_starttime(start_time);
622 event.set_loadedClass(k);
623 event.set_definingClassLoader(k->class_loader_data());
624 event.set_initiatingClassLoader(init_cld);
625 event.commit();
626 }
627 #endif // INCLUDE_TRACE
628 }
629
630 static void class_define_event(InstanceKlass* k,
631 const ClassLoaderData* def_cld) {
632 #if INCLUDE_TRACE
633 EventClassDefine event;
634 if (event.should_commit()) {
635 event.set_definedClass(k);
636 event.set_definingClassLoader(def_cld);
637 event.commit();
638 }
639 #endif // INCLUDE_TRACE
640 }
641
642 // Be careful when modifying this code: once you have run
643 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
644 // you need to find_and_remove it before returning.
645 // So be careful to not exit with a CHECK_ macro betweeen these calls.
646 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
647 Handle class_loader,
648 Handle protection_domain,
649 TRAPS) {
650 assert(name != NULL && !FieldType::is_array(name) &&
651 !FieldType::is_obj(name), "invalid class name");
652
653 Ticks class_load_start_time = Ticks::now();
654
655 HandleMark hm(THREAD);
656
657 // Fix for 4474172; see evaluation for more details
658 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
659 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
660
661 // Do lookup to see if class already exist and the protection domain
662 // has the right access
663 // This call uses find which checks protection domain already matches
664 // All subsequent calls use find_class, and set has_loaded_class so that
665 // before we return a result we call out to java to check for valid protection domain
666 // to allow returning the Klass* and add it to the pd_set if it is valid
667 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
668 int d_index = dictionary()->hash_to_index(d_hash);
669 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
670 protection_domain, THREAD);
671 if (probe != NULL) return probe;
672
673
674 // Non-bootstrap class loaders will call out to class loader and
675 // define via jvm/jni_DefineClass which will acquire the
676 // class loader object lock to protect against multiple threads
677 // defining the class in parallel by accident.
678 // This lock must be acquired here so the waiter will find
679 // any successful result in the SystemDictionary and not attempt
680 // the define
681 // ParallelCapable Classloaders and the bootstrap classloader,
682 // or all classloaders with UnsyncloadClass do not acquire lock here
683 bool DoObjectLock = true;
684 if (is_parallelCapable(class_loader)) {
685 DoObjectLock = false;
686 }
687
688 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
689 int p_index = placeholders()->hash_to_index(p_hash);
690
691 // Class is not in SystemDictionary so we have to do loading.
692 // Make sure we are synchronized on the class loader before we proceed
693 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
694 check_loader_lock_contention(lockObject, THREAD);
695 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
696
697 // Check again (after locking) if class already exist in SystemDictionary
698 bool class_has_been_loaded = false;
699 bool super_load_in_progress = false;
700 bool havesupername = false;
701 InstanceKlass* k = NULL;
702 PlaceholderEntry* placeholder;
703 Symbol* superclassname = NULL;
704
705 {
706 MutexLocker mu(SystemDictionary_lock, THREAD);
707 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
708 if (check != NULL) {
709 // Klass is already loaded, so just return it
710 class_has_been_loaded = true;
711 k = check;
712 } else {
713 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
714 if (placeholder && placeholder->super_load_in_progress()) {
715 super_load_in_progress = true;
716 if (placeholder->havesupername() == true) {
717 superclassname = placeholder->supername();
718 havesupername = true;
719 }
720 }
721 }
722 }
723
724 // If the class is in the placeholder table, class loading is in progress
725 if (super_load_in_progress && havesupername==true) {
726 k = handle_parallel_super_load(name,
727 superclassname,
728 class_loader,
729 protection_domain,
730 lockObject, THREAD);
731 if (HAS_PENDING_EXCEPTION) {
732 return NULL;
733 }
734 if (k != NULL) {
735 class_has_been_loaded = true;
736 }
737 }
738
739 bool throw_circularity_error = false;
740 if (!class_has_been_loaded) {
741 bool load_instance_added = false;
742
743 // add placeholder entry to record loading instance class
744 // Five cases:
745 // All cases need to prevent modifying bootclasssearchpath
746 // in parallel with a classload of same classname
747 // Redefineclasses uses existence of the placeholder for the duration
748 // of the class load to prevent concurrent redefinition of not completely
749 // defined classes.
750 // case 1. traditional classloaders that rely on the classloader object lock
751 // - no other need for LOAD_INSTANCE
752 // case 2. traditional classloaders that break the classloader object lock
753 // as a deadlock workaround. Detection of this case requires that
754 // this check is done while holding the classloader object lock,
755 // and that lock is still held when calling classloader's loadClass.
756 // For these classloaders, we ensure that the first requestor
757 // completes the load and other requestors wait for completion.
758 // case 3. UnsyncloadClass - don't use objectLocker
759 // With this flag, we allow parallel classloading of a
760 // class/classloader pair
761 // case4. Bootstrap classloader - don't own objectLocker
762 // This classloader supports parallelism at the classloader level,
763 // but only allows a single load of a class/classloader pair.
764 // No performance benefit and no deadlock issues.
765 // case 5. parallelCapable user level classloaders - without objectLocker
766 // Allow parallel classloading of a class/classloader pair
767
768 {
769 MutexLocker mu(SystemDictionary_lock, THREAD);
770 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
771 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
772 if (oldprobe) {
773 // only need check_seen_thread once, not on each loop
774 // 6341374 java/lang/Instrument with -Xcomp
775 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
776 throw_circularity_error = true;
777 } else {
778 // case 1: traditional: should never see load_in_progress.
779 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
780
781 // case 4: bootstrap classloader: prevent futile classloading,
782 // wait on first requestor
783 if (class_loader.is_null()) {
784 SystemDictionary_lock->wait();
785 } else {
786 // case 2: traditional with broken classloader lock. wait on first
787 // requestor.
788 double_lock_wait(lockObject, THREAD);
789 }
790 // Check if classloading completed while we were waiting
791 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
792 if (check != NULL) {
793 // Klass is already loaded, so just return it
794 k = check;
795 class_has_been_loaded = true;
796 }
797 // check if other thread failed to load and cleaned up
798 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
799 }
800 }
801 }
802 }
803 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
804 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
805 // LOAD_INSTANCE in parallel
806
807 if (!throw_circularity_error && !class_has_been_loaded) {
808 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
809 load_instance_added = true;
810 // For class loaders that do not acquire the classloader object lock,
811 // if they did not catch another thread holding LOAD_INSTANCE,
812 // need a check analogous to the acquire ObjectLocker/find_class
813 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
814 // one final check if the load has already completed
815 // class loaders holding the ObjectLock shouldn't find the class here
816 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
817 if (check != NULL) {
818 // Klass is already loaded, so return it after checking/adding protection domain
819 k = check;
820 class_has_been_loaded = true;
821 }
822 }
823 }
824
825 // must throw error outside of owning lock
826 if (throw_circularity_error) {
827 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
828 ResourceMark rm(THREAD);
829 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
830 }
831
832 if (!class_has_been_loaded) {
833
834 // Do actual loading
835 k = load_instance_class(name, class_loader, THREAD);
836
837 // For UnsyncloadClass only
838 // If they got a linkageError, check if a parallel class load succeeded.
839 // If it did, then for bytecode resolution the specification requires
840 // that we return the same result we did for the other thread, i.e. the
841 // successfully loaded InstanceKlass
842 // Should not get here for classloaders that support parallelism
843 // with the new cleaner mechanism, even with AllowParallelDefineClass
844 // Bootstrap goes through here to allow for an extra guarantee check
845 if (UnsyncloadClass || (class_loader.is_null())) {
846 if (k == NULL && HAS_PENDING_EXCEPTION
847 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
850 if (check != NULL) {
851 // Klass is already loaded, so just use it
852 k = check;
853 CLEAR_PENDING_EXCEPTION;
854 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
855 }
856 }
857 }
858
859 // If everything was OK (no exceptions, no null return value), and
860 // class_loader is NOT the defining loader, do a little more bookkeeping.
861 if (!HAS_PENDING_EXCEPTION && k != NULL &&
862 k->class_loader() != class_loader()) {
863
864 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
865
866 // Need to check for a PENDING_EXCEPTION again; check_constraints
867 // can throw and doesn't use the CHECK macro.
868 if (!HAS_PENDING_EXCEPTION) {
869 { // Grabbing the Compile_lock prevents systemDictionary updates
870 // during compilations.
871 MutexLocker mu(Compile_lock, THREAD);
872 update_dictionary(d_index, d_hash, p_index, p_hash,
873 k, class_loader, THREAD);
874 }
875
876 if (JvmtiExport::should_post_class_load()) {
877 Thread *thread = THREAD;
878 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
879 JvmtiExport::post_class_load((JavaThread *) thread, k);
880 }
881 }
882 }
883 } // load_instance_class loop
884
885 if (load_instance_added == true) {
886 // clean up placeholder entries for LOAD_INSTANCE success or error
887 // This brackets the SystemDictionary updates for both defining
888 // and initiating loaders
889 MutexLocker mu(SystemDictionary_lock, THREAD);
890 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
891 SystemDictionary_lock->notify_all();
892 }
893 }
894
895 if (HAS_PENDING_EXCEPTION || k == NULL) {
896 return NULL;
897 }
898
899 post_class_load_event(class_load_start_time, k, loader_data);
900
901 #ifdef ASSERT
902 {
903 ClassLoaderData* loader_data = k->class_loader_data();
904 MutexLocker mu(SystemDictionary_lock, THREAD);
905 Klass* kk = find_class(name, loader_data);
906 assert(kk == k, "should be present in dictionary");
907 }
908 #endif
909
910 // return if the protection domain in NULL
911 if (protection_domain() == NULL) return k;
912
913 // Check the protection domain has the right access
914 {
915 MutexLocker mu(SystemDictionary_lock, THREAD);
916 // Note that we have an entry, and entries can be deleted only during GC,
917 // so we cannot allow GC to occur while we're holding this entry.
918 // We're using a NoSafepointVerifier to catch any place where we
919 // might potentially do a GC at all.
920 // Dictionary::do_unloading() asserts that classes in SD are only
921 // unloaded at a safepoint. Anonymous classes are not in SD.
922 NoSafepointVerifier nosafepoint;
923 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
924 loader_data,
925 protection_domain)) {
926 return k;
927 }
928 }
929
930 // Verify protection domain. If it fails an exception is thrown
931 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
932
933 return k;
934 }
935
936
937 // This routine does not lock the system dictionary.
938 //
939 // Since readers don't hold a lock, we must make sure that system
940 // dictionary entries are only removed at a safepoint (when only one
941 // thread is running), and are added to in a safe way (all links must
942 // be updated in an MT-safe manner).
943 //
944 // Callers should be aware that an entry could be added just after
945 // _dictionary->bucket(index) is read here, so the caller will not see
946 // the new entry.
947
948 Klass* SystemDictionary::find(Symbol* class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 TRAPS) {
952
953 // The result of this call should be consistent with the result
954 // of the call to resolve_instance_class_or_null().
955 // See evaluation 6790209 and 4474172 for more details.
956 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
957 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
958
959 if (loader_data == NULL) {
960 // If the ClassLoaderData has not been setup,
961 // then the class loader has no entries in the dictionary.
962 return NULL;
963 }
964
965 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
966 int d_index = dictionary()->hash_to_index(d_hash);
967
968 {
969 // Note that we have an entry, and entries can be deleted only during GC,
970 // so we cannot allow GC to occur while we're holding this entry.
971 // We're using a NoSafepointVerifier to catch any place where we
972 // might potentially do a GC at all.
973 // Dictionary::do_unloading() asserts that classes in SD are only
974 // unloaded at a safepoint. Anonymous classes are not in SD.
975 NoSafepointVerifier nosafepoint;
976 return dictionary()->find(d_index, d_hash, class_name, loader_data,
977 protection_domain, THREAD);
978 }
979 }
980
981
982 // Look for a loaded instance or array klass by name. Do not do any loading.
983 // return NULL in case of error.
984 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
985 Handle class_loader,
986 Handle protection_domain,
987 TRAPS) {
988 Klass* k = NULL;
989 assert(class_name != NULL, "class name must be non NULL");
990
991 if (FieldType::is_array(class_name)) {
992 // The name refers to an array. Parse the name.
993 // dimension and object_key in FieldArrayInfo are assigned as a
994 // side-effect of this call
995 FieldArrayInfo fd;
996 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
997 if (t != T_OBJECT) {
998 k = Universe::typeArrayKlassObj(t);
999 } else {
1000 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1001 }
1002 if (k != NULL) {
1003 k = k->array_klass_or_null(fd.dimension());
1004 }
1005 } else {
1006 k = find(class_name, class_loader, protection_domain, THREAD);
1007 }
1008 return k;
1009 }
1010
1011 // Note: this method is much like resolve_from_stream, but
1012 // does not publish the classes via the SystemDictionary.
1013 // Handles unsafe_DefineAnonymousClass and redefineclasses
1014 // RedefinedClasses do not add to the class hierarchy
1015 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1016 Handle class_loader,
1017 Handle protection_domain,
1018 ClassFileStream* st,
1019 const InstanceKlass* host_klass,
1020 GrowableArray<Handle>* cp_patches,
1021 TRAPS) {
1022
1023 Ticks class_load_start_time = Ticks::now();
1024
1025 ClassLoaderData* loader_data;
1026 if (host_klass != NULL) {
1027 // Create a new CLD for anonymous class, that uses the same class loader
1028 // as the host_klass
1029 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1030 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1031 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1032 loader_data->record_dependency(host_klass, CHECK_NULL);
1033 } else {
1034 loader_data = ClassLoaderData::class_loader_data(class_loader());
1035 }
1036
1037 assert(st != NULL, "invariant");
1038 assert(st->need_verify(), "invariant");
1039
1040 // Parse stream and create a klass.
1041 // Note that we do this even though this klass might
1042 // already be present in the SystemDictionary, otherwise we would not
1043 // throw potential ClassFormatErrors.
1044
1045 InstanceKlass* k = KlassFactory::create_from_stream(st,
1046 class_name,
1047 loader_data,
1048 protection_domain,
1049 host_klass,
1050 cp_patches,
1051 CHECK_NULL);
1052
1053 if (host_klass != NULL && k != NULL) {
1054 // If it's anonymous, initialize it now, since nobody else will.
1055
1056 {
1057 MutexLocker mu_r(Compile_lock, THREAD);
1058
1059 // Add to class hierarchy, initialize vtables, and do possible
1060 // deoptimizations.
1061 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1062
1063 // But, do not add to system dictionary.
1064
1065 // compiled code dependencies need to be validated anyway
1066 notice_modification();
1067 }
1068
1069 // Rewrite and patch constant pool here.
1070 k->link_class(CHECK_NULL);
1071 if (cp_patches != NULL) {
1072 k->constants()->patch_resolved_references(cp_patches);
1073 }
1074 k->eager_initialize(CHECK_NULL);
1075
1076 // notify jvmti
1077 if (JvmtiExport::should_post_class_load()) {
1078 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1079 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1080 }
1081
1082 post_class_load_event(class_load_start_time, k, loader_data);
1083 }
1084 assert(host_klass != NULL || NULL == cp_patches,
1085 "cp_patches only found with host_klass");
1086
1087 return k;
1088 }
1089
1090 // Add a klass to the system from a stream (called by jni_DefineClass and
1091 // JVM_DefineClass).
1092 // Note: class_name can be NULL. In that case we do not know the name of
1093 // the class until we have parsed the stream.
1094
1095 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1096 Handle class_loader,
1097 Handle protection_domain,
1098 ClassFileStream* st,
1099 TRAPS) {
1100
1101 HandleMark hm(THREAD);
1102
1103 // Classloaders that support parallelism, e.g. bootstrap classloader,
1104 // or all classloaders with UnsyncloadClass do not acquire lock here
1105 bool DoObjectLock = true;
1106 if (is_parallelCapable(class_loader)) {
1107 DoObjectLock = false;
1108 }
1109
1110 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1111
1112 // Make sure we are synchronized on the class loader before we proceed
1113 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1114 check_loader_lock_contention(lockObject, THREAD);
1115 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1116
1117 assert(st != NULL, "invariant");
1118
1119 // Parse the stream and create a klass.
1120 // Note that we do this even though this klass might
1121 // already be present in the SystemDictionary, otherwise we would not
1122 // throw potential ClassFormatErrors.
1123 InstanceKlass* k = NULL;
1124
1125 #if INCLUDE_CDS
1126 k = SystemDictionaryShared::lookup_from_stream(class_name,
1127 class_loader,
1128 protection_domain,
1129 st,
1130 CHECK_NULL);
1131 #endif
1132
1133 if (k == NULL) {
1134 if (st->buffer() == NULL) {
1135 return NULL;
1136 }
1137 k = KlassFactory::create_from_stream(st,
1138 class_name,
1139 loader_data,
1140 protection_domain,
1141 NULL, // host_klass
1142 NULL, // cp_patches
1143 CHECK_NULL);
1144 }
1145
1146 assert(k != NULL, "no klass created");
1147 Symbol* h_name = k->name();
1148 assert(class_name == NULL || class_name == h_name, "name mismatch");
1149
1150 // Add class just loaded
1151 // If a class loader supports parallel classloading handle parallel define requests
1152 // find_or_define_instance_class may return a different InstanceKlass
1153 if (is_parallelCapable(class_loader)) {
1154 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1155 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1156 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1157 assert(defined_k != NULL, "Should have a klass if there's no exception");
1158 loader_data->add_to_deallocate_list(k);
1159 k = defined_k;
1160 }
1161 } else {
1162 define_instance_class(k, THREAD);
1163 }
1164
1165 // If defining the class throws an exception register 'k' for cleanup.
1166 if (HAS_PENDING_EXCEPTION) {
1167 assert(k != NULL, "Must have an instance klass here!");
1168 loader_data->add_to_deallocate_list(k);
1169 return NULL;
1170 }
1171
1172 // Make sure we have an entry in the SystemDictionary on success
1173 debug_only( {
1174 MutexLocker mu(SystemDictionary_lock, THREAD);
1175
1176 Klass* check = find_class(h_name, k->class_loader_data());
1177 assert(check == k, "should be present in the dictionary");
1178 } );
1179
1180 return k;
1181 }
1182
1183 #if INCLUDE_CDS
1184 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1185 int number_of_entries) {
1186 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1187 "bad shared dictionary size.");
1188 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1189 }
1190
1191
1192 // If there is a shared dictionary, then find the entry for the
1193 // given shared system class, if any.
1194
1195 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1196 if (shared_dictionary() != NULL) {
1197 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1198 int d_index = shared_dictionary()->hash_to_index(d_hash);
1199
1200 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1201 } else {
1202 return NULL;
1203 }
1204 }
1205
1206
1207 // Load a class from the shared spaces (found through the shared system
1208 // dictionary). Force the superclass and all interfaces to be loaded.
1209 // Update the class definition to include sibling classes and no
1210 // subclasses (yet). [Classes in the shared space are not part of the
1211 // object hierarchy until loaded.]
1212
1213 InstanceKlass* SystemDictionary::load_shared_class(
1214 Symbol* class_name, Handle class_loader, TRAPS) {
1215 InstanceKlass* ik = find_shared_class(class_name);
1216 // Make sure we only return the boot class for the NULL classloader.
1217 if (ik != NULL &&
1218 ik->is_shared_boot_class() && class_loader.is_null()) {
1219 Handle protection_domain;
1220 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1221 }
1222 return NULL;
1223 }
1224
1225 // Check if a shared class can be loaded by the specific classloader:
1226 //
1227 // NULL classloader:
1228 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1229 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1230 // be defined in an unnamed module.
1231 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1232 InstanceKlass* ik,
1233 Handle class_loader, TRAPS) {
1234 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1235 "Cannot use sharing if java.base is patched");
1236 ResourceMark rm;
1237 int path_index = ik->shared_classpath_index();
1238 SharedClassPathEntry* ent =
1239 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1240 if (!Universe::is_module_initialized()) {
1241 assert(ent != NULL && ent->is_jrt(),
1242 "Loading non-bootstrap classes before the module system is initialized");
1243 assert(class_loader.is_null(), "sanity");
1244 return true;
1245 }
1246 // Get the pkg_entry from the classloader
1247 TempNewSymbol pkg_name = NULL;
1248 PackageEntry* pkg_entry = NULL;
1249 ModuleEntry* mod_entry = NULL;
1250 const char* pkg_string = NULL;
1251 ClassLoaderData* loader_data = class_loader_data(class_loader);
1252 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1253 if (pkg_name != NULL) {
1254 pkg_string = pkg_name->as_C_string();
1255 if (loader_data != NULL) {
1256 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1257 }
1258 if (pkg_entry != NULL) {
1259 mod_entry = pkg_entry->module();
1260 }
1261 }
1262
1263 // If the archived class is from a module that has been patched at runtime,
1264 // the class cannot be loaded from the archive.
1265 if (mod_entry != NULL && mod_entry->is_patched()) {
1266 return false;
1267 }
1268
1269 if (class_loader.is_null()) {
1270 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1271 // The NULL classloader can load archived class originated from the
1272 // "modules" jimage and the -Xbootclasspath/a. For class from the
1273 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1274 // by the NULL classloader.
1275 if (mod_entry != NULL) {
1276 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1277 // ModuleEntry's location agrees with the archived class' origination.
1278 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1279 return true; // Module class from the "module" jimage
1280 }
1281 }
1282
1283 // If the archived class is not from the "module" jimage, the class can be
1284 // loaded by the NULL classloader if
1285 //
1286 // 1. the class is from the unamed package
1287 // 2. or, the class is not from a module defined in the NULL classloader
1288 // 3. or, the class is from an unamed module
1289 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1290 // the class is from the -Xbootclasspath/a
1291 if (pkg_string == NULL ||
1292 pkg_entry == NULL ||
1293 pkg_entry->in_unnamed_module()) {
1294 assert(mod_entry == NULL ||
1295 mod_entry == loader_data->unnamed_module(),
1296 "the unnamed module is not defined in the classloader");
1297 return true;
1298 }
1299 }
1300 return false;
1301 } else {
1302 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1303 ik, class_loader, pkg_string, pkg_name,
1304 pkg_entry, mod_entry, CHECK_(false));
1305 return res;
1306 }
1307 }
1308
1309 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1310 Handle class_loader,
1311 Handle protection_domain, TRAPS) {
1312
1313 if (ik != NULL) {
1314 Symbol* class_name = ik->name();
1315
1316 bool visible = is_shared_class_visible(
1317 class_name, ik, class_loader, CHECK_NULL);
1318 if (!visible) {
1319 return NULL;
1320 }
1321
1322 // Resolve the superclass and interfaces. They must be the same
1323 // as in dump time, because the layout of <ik> depends on
1324 // the specific layout of ik->super() and ik->local_interfaces().
1325 //
1326 // If unexpected superclass or interfaces are found, we cannot
1327 // load <ik> from the shared archive.
1328
1329 if (ik->super() != NULL) {
1330 Symbol* cn = ik->super()->name();
1331 Klass *s = resolve_super_or_fail(class_name, cn,
1332 class_loader, protection_domain, true, CHECK_NULL);
1333 if (s != ik->super()) {
1334 // The dynamically resolved super class is not the same as the one we used during dump time,
1335 // so we cannot use ik.
1336 return NULL;
1337 } else {
1338 assert(s->is_shared(), "must be");
1339 }
1340 }
1341
1342 Array<Klass*>* interfaces = ik->local_interfaces();
1343 int num_interfaces = interfaces->length();
1344 for (int index = 0; index < num_interfaces; index++) {
1345 Klass* k = interfaces->at(index);
1346 Symbol* name = k->name();
1347 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1348 if (k != i) {
1349 // The dynamically resolved interface class is not the same as the one we used during dump time,
1350 // so we cannot use ik.
1351 return NULL;
1352 } else {
1353 assert(i->is_shared(), "must be");
1354 }
1355 }
1356
1357 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1358 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1359 if (new_ik != NULL) {
1360 // The class is changed by CFLH. Return the new class. The shared class is
1361 // not used.
1362 return new_ik;
1363 }
1364
1365 // Adjust methods to recover missing data. They need addresses for
1366 // interpreter entry points and their default native method address
1367 // must be reset.
1368
1369 // Updating methods must be done under a lock so multiple
1370 // threads don't update these in parallel
1371 //
1372 // Shared classes are all currently loaded by either the bootstrap or
1373 // internal parallel class loaders, so this will never cause a deadlock
1374 // on a custom class loader lock.
1375
1376 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1377 {
1378 HandleMark hm(THREAD);
1379 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1380 check_loader_lock_contention(lockObject, THREAD);
1381 ObjectLocker ol(lockObject, THREAD, true);
1382 // prohibited package check assumes all classes loaded from archive call
1383 // restore_unshareable_info which calls ik->set_package()
1384 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1385 }
1386
1387 if (log_is_enabled(Info, class, load)) {
1388 ik->print_loading_log(LogLevel::Info, loader_data, NULL, NULL);
1389 }
1390 // No 'else' here as logging levels are not mutually exclusive
1391
1392 if (log_is_enabled(Debug, class, load)) {
1393 ik->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL);
1394 }
1395
1396 // For boot loader, ensure that GetSystemPackage knows that a class in this
1397 // package was loaded.
1398 if (class_loader.is_null()) {
1399 int path_index = ik->shared_classpath_index();
1400 ResourceMark rm;
1401 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1402 }
1403
1404 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1405 // Only dump the classes that can be stored into CDS archive
1406 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1407 ResourceMark rm(THREAD);
1408 classlist_file->print_cr("%s", ik->name()->as_C_string());
1409 classlist_file->flush();
1410 }
1411 }
1412
1413 // notify a class loaded from shared object
1414 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1415 }
1416
1417 ik->set_has_passed_fingerprint_check(false);
1418 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1419 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1420 uint64_t cds_fp = ik->get_stored_fingerprint();
1421 if (aot_fp != 0 && aot_fp == cds_fp) {
1422 // This class matches with a class saved in an AOT library
1423 ik->set_has_passed_fingerprint_check(true);
1424 } else {
1425 ResourceMark rm;
1426 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1427 }
1428 }
1429 return ik;
1430 }
1431 #endif // INCLUDE_CDS
1432
1433 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1434
1435 if (class_loader.is_null()) {
1436 ResourceMark rm;
1437 PackageEntry* pkg_entry = NULL;
1438 bool search_only_bootloader_append = false;
1439 ClassLoaderData *loader_data = class_loader_data(class_loader);
1440
1441 // Find the package in the boot loader's package entry table.
1442 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1443 if (pkg_name != NULL) {
1444 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1445 }
1446
1447 // Prior to attempting to load the class, enforce the boot loader's
1448 // visibility boundaries.
1449 if (!Universe::is_module_initialized()) {
1450 // During bootstrapping, prior to module initialization, any
1451 // class attempting to be loaded must be checked against the
1452 // java.base packages in the boot loader's PackageEntryTable.
1453 // No class outside of java.base is allowed to be loaded during
1454 // this bootstrapping window.
1455 if (!DumpSharedSpaces) {
1456 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1457 // Class is either in the unnamed package or in
1458 // a named package within the unnamed module. Either
1459 // case is outside of java.base, do not attempt to
1460 // load the class post java.base definition. If
1461 // java.base has not been defined, let the class load
1462 // and its package will be checked later by
1463 // ModuleEntryTable::verify_javabase_packages.
1464 if (ModuleEntryTable::javabase_defined()) {
1465 return NULL;
1466 }
1467 } else {
1468 // Check that the class' package is defined within java.base.
1469 ModuleEntry* mod_entry = pkg_entry->module();
1470 Symbol* mod_entry_name = mod_entry->name();
1471 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1472 return NULL;
1473 }
1474 }
1475 }
1476 } else {
1477 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1478 // After the module system has been initialized, check if the class'
1479 // package is in a module defined to the boot loader.
1480 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1481 // Class is either in the unnamed package, in a named package
1482 // within a module not defined to the boot loader or in a
1483 // a named package within the unnamed module. In all cases,
1484 // limit visibility to search for the class only in the boot
1485 // loader's append path.
1486 search_only_bootloader_append = true;
1487 }
1488 }
1489
1490 // Prior to bootstrapping's module initialization, never load a class outside
1491 // of the boot loader's module path
1492 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1493 !search_only_bootloader_append,
1494 "Attempt to load a class outside of boot loader's module path");
1495
1496 // Search the shared system dictionary for classes preloaded into the
1497 // shared spaces.
1498 InstanceKlass* k = NULL;
1499 {
1500 #if INCLUDE_CDS
1501 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1502 k = load_shared_class(class_name, class_loader, THREAD);
1503 #endif
1504 }
1505
1506 if (k == NULL) {
1507 // Use VM class loader
1508 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1509 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1510 }
1511
1512 // find_or_define_instance_class may return a different InstanceKlass
1513 if (k != NULL) {
1514 InstanceKlass* defined_k =
1515 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1516 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1517 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1518 assert(defined_k != NULL, "Should have a klass if there's no exception");
1519 loader_data->add_to_deallocate_list(k);
1520 k = defined_k;
1521 } else if (HAS_PENDING_EXCEPTION) {
1522 loader_data->add_to_deallocate_list(k);
1523 return NULL;
1524 }
1525 }
1526 return k;
1527 } else {
1528 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1529 ResourceMark rm(THREAD);
1530
1531 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1532 JavaThread* jt = (JavaThread*) THREAD;
1533
1534 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1535 ClassLoader::perf_app_classload_selftime(),
1536 ClassLoader::perf_app_classload_count(),
1537 jt->get_thread_stat()->perf_recursion_counts_addr(),
1538 jt->get_thread_stat()->perf_timers_addr(),
1539 PerfClassTraceTime::CLASS_LOAD);
1540
1541 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1542 // Translate to external class name format, i.e., convert '/' chars to '.'
1543 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1544
1545 JavaValue result(T_OBJECT);
1546
1547 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1548
1549 // Call public unsynchronized loadClass(String) directly for all class loaders
1550 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1551 // acquire a class-name based lock rather than the class loader object lock.
1552 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1553 // so the call to loadClassInternal() was not required.
1554 //
1555 // UnsyncloadClass flag means both call loadClass(String) and do
1556 // not acquire the class loader lock even for class loaders that are
1557 // not parallelCapable. This was a risky transitional
1558 // flag for diagnostic purposes only. It is risky to call
1559 // custom class loaders without synchronization.
1560 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1561 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1562 // Do NOT assume this will be supported in future releases.
1563 //
1564 // Added MustCallLoadClassInternal in case we discover in the field
1565 // a customer that counts on this call
1566 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1567 JavaCalls::call_special(&result,
1568 class_loader,
1569 spec_klass,
1570 vmSymbols::loadClassInternal_name(),
1571 vmSymbols::string_class_signature(),
1572 string,
1573 CHECK_NULL);
1574 } else {
1575 JavaCalls::call_virtual(&result,
1576 class_loader,
1577 spec_klass,
1578 vmSymbols::loadClass_name(),
1579 vmSymbols::string_class_signature(),
1580 string,
1581 CHECK_NULL);
1582 }
1583
1584 assert(result.get_type() == T_OBJECT, "just checking");
1585 oop obj = (oop) result.get_jobject();
1586
1587 // Primitive classes return null since forName() can not be
1588 // used to obtain any of the Class objects representing primitives or void
1589 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1590 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1591 // For user defined Java class loaders, check that the name returned is
1592 // the same as that requested. This check is done for the bootstrap
1593 // loader when parsing the class file.
1594 if (class_name == k->name()) {
1595 return k;
1596 }
1597 }
1598 // Class is not found or has the wrong name, return NULL
1599 return NULL;
1600 }
1601 }
1602
1603 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1604
1605 HandleMark hm(THREAD);
1606 ClassLoaderData* loader_data = k->class_loader_data();
1607 Handle class_loader_h(THREAD, loader_data->class_loader());
1608
1609 // for bootstrap and other parallel classloaders don't acquire lock,
1610 // use placeholder token
1611 // If a parallelCapable class loader calls define_instance_class instead of
1612 // find_or_define_instance_class to get here, we have a timing
1613 // hole with systemDictionary updates and check_constraints
1614 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1615 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1616 compute_loader_lock_object(class_loader_h, THREAD)),
1617 "define called without lock");
1618 }
1619
1620 // Check class-loading constraints. Throw exception if violation is detected.
1621 // Grabs and releases SystemDictionary_lock
1622 // The check_constraints/find_class call and update_dictionary sequence
1623 // must be "atomic" for a specific class/classloader pair so we never
1624 // define two different instanceKlasses for that class/classloader pair.
1625 // Existing classloaders will call define_instance_class with the
1626 // classloader lock held
1627 // Parallel classloaders will call find_or_define_instance_class
1628 // which will require a token to perform the define class
1629 Symbol* name_h = k->name();
1630 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1631 int d_index = dictionary()->hash_to_index(d_hash);
1632 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1633
1634 // Register class just loaded with class loader (placed in Vector)
1635 // Note we do this before updating the dictionary, as this can
1636 // fail with an OutOfMemoryError (if it does, we will *not* put this
1637 // class in the dictionary and will not update the class hierarchy).
1638 // JVMTI FollowReferences needs to find the classes this way.
1639 if (k->class_loader() != NULL) {
1640 methodHandle m(THREAD, Universe::loader_addClass_method());
1641 JavaValue result(T_VOID);
1642 JavaCallArguments args(class_loader_h);
1643 args.push_oop(Handle(THREAD, k->java_mirror()));
1644 JavaCalls::call(&result, m, &args, CHECK);
1645 }
1646
1647 // Add the new class. We need recompile lock during update of CHA.
1648 {
1649 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1650 int p_index = placeholders()->hash_to_index(p_hash);
1651
1652 MutexLocker mu_r(Compile_lock, THREAD);
1653
1654 // Add to class hierarchy, initialize vtables, and do possible
1655 // deoptimizations.
1656 add_to_hierarchy(k, CHECK); // No exception, but can block
1657
1658 // Add to systemDictionary - so other classes can see it.
1659 // Grabs and releases SystemDictionary_lock
1660 update_dictionary(d_index, d_hash, p_index, p_hash,
1661 k, class_loader_h, THREAD);
1662 }
1663 k->eager_initialize(THREAD);
1664
1665 // notify jvmti
1666 if (JvmtiExport::should_post_class_load()) {
1667 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1668 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1669
1670 }
1671 class_define_event(k, loader_data);
1672 }
1673
1674 // Support parallel classloading
1675 // All parallel class loaders, including bootstrap classloader
1676 // lock a placeholder entry for this class/class_loader pair
1677 // to allow parallel defines of different classes for this class loader
1678 // With AllowParallelDefine flag==true, in case they do not synchronize around
1679 // FindLoadedClass/DefineClass, calls, we check for parallel
1680 // loading for them, wait if a defineClass is in progress
1681 // and return the initial requestor's results
1682 // This flag does not apply to the bootstrap classloader.
1683 // With AllowParallelDefine flag==false, call through to define_instance_class
1684 // which will throw LinkageError: duplicate class definition.
1685 // False is the requested default.
1686 // For better performance, the class loaders should synchronize
1687 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1688 // potentially waste time reading and parsing the bytestream.
1689 // Note: VM callers should ensure consistency of k/class_name,class_loader
1690 // Be careful when modifying this code: once you have run
1691 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1692 // you need to find_and_remove it before returning.
1693 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1694 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1695 InstanceKlass* k, TRAPS) {
1696
1697 Symbol* name_h = k->name(); // passed in class_name may be null
1698 ClassLoaderData* loader_data = class_loader_data(class_loader);
1699
1700 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1701 int d_index = dictionary()->hash_to_index(d_hash);
1702
1703 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1704 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1705 int p_index = placeholders()->hash_to_index(p_hash);
1706 PlaceholderEntry* probe;
1707
1708 {
1709 MutexLocker mu(SystemDictionary_lock, THREAD);
1710 // First check if class already defined
1711 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1712 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1713 if (check != NULL) {
1714 return check;
1715 }
1716 }
1717
1718 // Acquire define token for this class/classloader
1719 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1720 // Wait if another thread defining in parallel
1721 // All threads wait - even those that will throw duplicate class: otherwise
1722 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1723 // if other thread has not finished updating dictionary
1724 while (probe->definer() != NULL) {
1725 SystemDictionary_lock->wait();
1726 }
1727 // Only special cases allow parallel defines and can use other thread's results
1728 // Other cases fall through, and may run into duplicate defines
1729 // caught by finding an entry in the SystemDictionary
1730 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1731 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1732 SystemDictionary_lock->notify_all();
1733 #ifdef ASSERT
1734 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1735 assert(check != NULL, "definer missed recording success");
1736 #endif
1737 return probe->instance_klass();
1738 } else {
1739 // This thread will define the class (even if earlier thread tried and had an error)
1740 probe->set_definer(THREAD);
1741 }
1742 }
1743
1744 define_instance_class(k, THREAD);
1745
1746 Handle linkage_exception = Handle(); // null handle
1747
1748 // definer must notify any waiting threads
1749 {
1750 MutexLocker mu(SystemDictionary_lock, THREAD);
1751 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1752 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1753 if (probe != NULL) {
1754 if (HAS_PENDING_EXCEPTION) {
1755 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1756 CLEAR_PENDING_EXCEPTION;
1757 } else {
1758 probe->set_instance_klass(k);
1759 }
1760 probe->set_definer(NULL);
1761 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1762 SystemDictionary_lock->notify_all();
1763 }
1764 }
1765
1766 // Can't throw exception while holding lock due to rank ordering
1767 if (linkage_exception() != NULL) {
1768 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1769 }
1770
1771 return k;
1772 }
1773 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1774 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1775 if (class_loader.is_null()) {
1776 return Handle(THREAD, _system_loader_lock_obj);
1777 } else {
1778 return class_loader;
1779 }
1780 }
1781
1782 // This method is added to check how often we have to wait to grab loader
1783 // lock. The results are being recorded in the performance counters defined in
1784 // ClassLoader::_sync_systemLoaderLockContentionRate and
1785 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1786 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1787 if (!UsePerfData) {
1788 return;
1789 }
1790
1791 assert(!loader_lock.is_null(), "NULL lock object");
1792
1793 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1794 == ObjectSynchronizer::owner_other) {
1795 // contention will likely happen, so increment the corresponding
1796 // contention counter.
1797 if (loader_lock() == _system_loader_lock_obj) {
1798 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1799 } else {
1800 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1801 }
1802 }
1803 }
1804
1805 // ----------------------------------------------------------------------------
1806 // Lookup
1807
1808 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1809 Symbol* class_name,
1810 ClassLoaderData* loader_data) {
1811 assert_locked_or_safepoint(SystemDictionary_lock);
1812 assert (index == dictionary()->index_for(class_name, loader_data),
1813 "incorrect index?");
1814
1815 return dictionary()->find_class(index, hash, class_name, loader_data);
1816 }
1817
1818
1819 // Basic find on classes in the midst of being loaded
1820 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1821 ClassLoaderData* loader_data) {
1822 assert_locked_or_safepoint(SystemDictionary_lock);
1823 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1824 int p_index = placeholders()->hash_to_index(p_hash);
1825 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1826 }
1827
1828
1829 // Used for assertions and verification only
1830 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1831 #ifndef ASSERT
1832 guarantee(VerifyBeforeGC ||
1833 VerifyDuringGC ||
1834 VerifyBeforeExit ||
1835 VerifyDuringStartup ||
1836 VerifyAfterGC, "too expensive");
1837 #endif
1838 assert_locked_or_safepoint(SystemDictionary_lock);
1839
1840 // First look in the loaded class array
1841 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1842 int d_index = dictionary()->hash_to_index(d_hash);
1843 return find_class(d_index, d_hash, class_name, loader_data);
1844 }
1845
1846
1847 // Get the next class in the dictionary.
1848 Klass* SystemDictionary::try_get_next_class() {
1849 return dictionary()->try_get_next_class();
1850 }
1851
1852
1853 // ----------------------------------------------------------------------------
1854 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1855 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1856 // before a new class is used.
1857
1858 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1859 assert(k != NULL, "just checking");
1860 assert_locked_or_safepoint(Compile_lock);
1861
1862 // Link into hierachy. Make sure the vtables are initialized before linking into
1863 k->append_to_sibling_list(); // add to superklass/sibling list
1864 k->process_interfaces(THREAD); // handle all "implements" declarations
1865 k->set_init_state(InstanceKlass::loaded);
1866 // Now flush all code that depended on old class hierarchy.
1867 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1868 // Also, first reinitialize vtable because it may have gotten out of synch
1869 // while the new class wasn't connected to the class hierarchy.
1870 CodeCache::flush_dependents_on(k);
1871 }
1872
1873 // ----------------------------------------------------------------------------
1874 // GC support
1875
1876 // Following roots during mark-sweep is separated in two phases.
1877 //
1878 // The first phase follows preloaded classes and all other system
1879 // classes, since these will never get unloaded anyway.
1880 //
1881 // The second phase removes (unloads) unreachable classes from the
1882 // system dictionary and follows the remaining classes' contents.
1883
1884 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1885 roots_oops_do(blk, NULL);
1886 }
1887
1888 // Calculate a "good" systemdictionary size based
1889 // on predicted or current loaded classes count
1890 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1891 int newsize = _old_default_sdsize;
1892 if ((classcount > 0) && !DumpSharedSpaces) {
1893 int desiredsize = classcount/_average_depth_goal;
1894 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1895 newsize = _primelist[++_sdgeneration]) {
1896 if (desiredsize <= newsize) {
1897 break;
1898 }
1899 }
1900 }
1901 return newsize;
1902 }
1903
1904 #ifdef ASSERT
1905 class VerifySDReachableAndLiveClosure : public OopClosure {
1906 private:
1907 BoolObjectClosure* _is_alive;
1908
1909 template <class T> void do_oop_work(T* p) {
1910 oop obj = oopDesc::load_decode_heap_oop(p);
1911 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1912 }
1913
1914 public:
1915 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1916
1917 virtual void do_oop(oop* p) { do_oop_work(p); }
1918 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1919 };
1920 #endif
1921
1922 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1923 // Note: anonymous classes are not in the SD.
1924 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1925 bool clean_previous_versions) {
1926 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1927 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1928 clean_previous_versions);
1929 if (unloading_occurred) {
1930 dictionary()->do_unloading();
1931 constraints()->purge_loader_constraints();
1932 resolution_errors()->purge_resolution_errors();
1933 }
1934 // Oops referenced by the system dictionary may get unreachable independently
1935 // of the class loader (eg. cached protection domain oops). So we need to
1936 // explicitly unlink them here instead of in Dictionary::do_unloading.
1937 dictionary()->unlink(is_alive);
1938 #ifdef ASSERT
1939 VerifySDReachableAndLiveClosure cl(is_alive);
1940 dictionary()->oops_do(&cl);
1941 #endif
1942 return unloading_occurred;
1943 }
1944
1945 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1946 strong->do_oop(&_java_system_loader);
1947 strong->do_oop(&_system_loader_lock_obj);
1948 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1949
1950 // Adjust dictionary
1951 dictionary()->roots_oops_do(strong, weak);
1952
1953 // Visit extra methods
1954 invoke_method_table()->oops_do(strong);
1955 }
1956
1957 void SystemDictionary::oops_do(OopClosure* f) {
1958 f->do_oop(&_java_system_loader);
1959 f->do_oop(&_system_loader_lock_obj);
1960 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1961
1962 // Adjust dictionary
1963 dictionary()->oops_do(f);
1964
1965 // Visit extra methods
1966 invoke_method_table()->oops_do(f);
1967 }
1968
1969 // Just the classes from defining class loaders
1970 // Don't iterate over placeholders
1971 void SystemDictionary::classes_do(void f(Klass*)) {
1972 dictionary()->classes_do(f);
1973 }
1974
1975 // Added for initialize_itable_for_klass
1976 // Just the classes from defining class loaders
1977 // Don't iterate over placeholders
1978 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1979 dictionary()->classes_do(f, CHECK);
1980 }
1981
1982 // All classes, and their class loaders
1983 // Don't iterate over placeholders
1984 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1985 dictionary()->classes_do(f);
1986 }
1987
1988 void SystemDictionary::methods_do(void f(Method*)) {
1989 // Walk methods in loaded classes
1990 ClassLoaderDataGraph::methods_do(f);
1991 // Walk method handle intrinsics
1992 invoke_method_table()->methods_do(f);
1993 }
1994
1995 void SystemDictionary::remove_classes_in_error_state() {
1996 dictionary()->remove_classes_in_error_state();
1997 }
1998
1999 // ----------------------------------------------------------------------------
2000 // Lazily load klasses
2001
2002 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2003 // if multiple threads calling this function, only one thread will load
2004 // the class. The other threads will find the loaded version once the
2005 // class is loaded.
2006 Klass* aos = _abstract_ownable_synchronizer_klass;
2007 if (aos == NULL) {
2008 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2009 // Force a fence to prevent any read before the write completes
2010 OrderAccess::fence();
2011 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2012 }
2013 }
2014
2015 // ----------------------------------------------------------------------------
2016 // Initialization
2017
2018 void SystemDictionary::initialize(TRAPS) {
2019 // Allocate arrays
2020 assert(dictionary() == NULL,
2021 "SystemDictionary should only be initialized once");
2022 _sdgeneration = 0;
2023 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2024 _placeholders = new PlaceholderTable(_nof_buckets);
2025 _number_of_modifications = 0;
2026 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2027 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2028 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2029
2030 // Allocate private object used as system class loader lock
2031 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2032 // Initialize basic classes
2033 initialize_preloaded_classes(CHECK);
2034 }
2035
2036 // Compact table of directions on the initialization of klasses:
2037 static const short wk_init_info[] = {
2038 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2039 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2040 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2041 | (int)SystemDictionary::option ),
2042 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2043 #undef WK_KLASS_INIT_INFO
2044 0
2045 };
2046
2047 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2048 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2049 int info = wk_init_info[id - FIRST_WKID];
2050 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2051 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2052 InstanceKlass** klassp = &_well_known_klasses[id];
2053
2054 bool must_load;
2055 #if INCLUDE_JVMCI
2056 if (EnableJVMCI) {
2057 // If JVMCI is enabled we require its classes to be found.
2058 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2059 } else
2060 #endif
2061 {
2062 must_load = (init_opt < SystemDictionary::Opt);
2063 }
2064
2065 if ((*klassp) == NULL) {
2066 Klass* k;
2067 if (must_load) {
2068 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2069 } else {
2070 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2071 }
2072 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2073 }
2074 return ((*klassp) != NULL);
2075 }
2076
2077 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2078 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2079 for (int id = (int)start_id; id < (int)limit_id; id++) {
2080 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2081 int info = wk_init_info[id - FIRST_WKID];
2082 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2083 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2084
2085 initialize_wk_klass((WKID)id, opt, CHECK);
2086 }
2087
2088 // move the starting value forward to the limit:
2089 start_id = limit_id;
2090 }
2091
2092 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2093 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2094
2095 // Create the ModuleEntry for java.base. This call needs to be done here,
2096 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2097 ClassLoader::classLoader_init2(CHECK);
2098
2099 // Preload commonly used klasses
2100 WKID scan = FIRST_WKID;
2101 // first do Object, then String, Class
2102 if (UseSharedSpaces) {
2103 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2104 // Initialize the constant pool for the Object_class
2105 Object_klass()->constants()->restore_unshareable_info(CHECK);
2106 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2107 } else {
2108 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2109 }
2110
2111 // Calculate offsets for String and Class classes since they are loaded and
2112 // can be used after this point.
2113 java_lang_String::compute_offsets();
2114 java_lang_Class::compute_offsets();
2115
2116 // Fixup mirrors for classes loaded before java.lang.Class.
2117 // These calls iterate over the objects currently in the perm gen
2118 // so calling them at this point is matters (not before when there
2119 // are fewer objects and not later after there are more objects
2120 // in the perm gen.
2121 Universe::initialize_basic_type_mirrors(CHECK);
2122 Universe::fixup_mirrors(CHECK);
2123
2124 // do a bunch more:
2125 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2126
2127 // Preload ref klasses and set reference types
2128 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2129 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2130
2131 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2132 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2133 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2134 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2135 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2136
2137 // JSR 292 classes
2138 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2139 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2140 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2141 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2142 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2143
2144 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2145 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2146 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2147 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2148 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2149 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2150 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2151 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2152 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2153 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2154
2155 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2156 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2157 _has_loadClassInternal = (method != NULL);
2158 }
2159 { // Compute whether we should use checkPackageAccess or NOT
2160 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2161 _has_checkPackageAccess = (method != NULL);
2162 }
2163 }
2164
2165 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2166 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2167 BasicType SystemDictionary::box_klass_type(Klass* k) {
2168 assert(k != NULL, "");
2169 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2170 if (_box_klasses[i] == k)
2171 return (BasicType)i;
2172 }
2173 return T_OBJECT;
2174 }
2175
2176 // Constraints on class loaders. The details of the algorithm can be
2177 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2178 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2179 // that the system dictionary needs to maintain a set of contraints that
2180 // must be satisfied by all classes in the dictionary.
2181 // if defining is true, then LinkageError if already in systemDictionary
2182 // if initiating loader, then ok if InstanceKlass matches existing entry
2183
2184 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2185 InstanceKlass* k,
2186 Handle class_loader, bool defining,
2187 TRAPS) {
2188 const char *linkage_error1 = NULL;
2189 const char *linkage_error2 = NULL;
2190 {
2191 Symbol* name = k->name();
2192 ClassLoaderData *loader_data = class_loader_data(class_loader);
2193
2194 MutexLocker mu(SystemDictionary_lock, THREAD);
2195
2196 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
2197 if (check != NULL) {
2198 // if different InstanceKlass - duplicate class definition,
2199 // else - ok, class loaded by a different thread in parallel,
2200 // we should only have found it if it was done loading and ok to use
2201 // system dictionary only holds instance classes, placeholders
2202 // also holds array classes
2203
2204 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2205 if ((defining == true) || (k != check)) {
2206 linkage_error1 = "loader (instance of ";
2207 linkage_error2 = "): attempted duplicate class definition for name: \"";
2208 } else {
2209 return;
2210 }
2211 }
2212
2213 #ifdef ASSERT
2214 Symbol* ph_check = find_placeholder(name, loader_data);
2215 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2216 #endif
2217
2218 if (linkage_error1 == NULL) {
2219 if (constraints()->check_or_update(k, class_loader, name) == false) {
2220 linkage_error1 = "loader constraint violation: loader (instance of ";
2221 linkage_error2 = ") previously initiated loading for a different type with name \"";
2222 }
2223 }
2224 }
2225
2226 // Throw error now if needed (cannot throw while holding
2227 // SystemDictionary_lock because of rank ordering)
2228
2229 if (linkage_error1) {
2230 ResourceMark rm(THREAD);
2231 const char* class_loader_name = loader_name(class_loader());
2232 char* type_name = k->name()->as_C_string();
2233 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2234 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2235 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2236 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2237 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2238 }
2239 }
2240
2241
2242 // Update system dictionary - done after check_constraint and add_to_hierachy
2243 // have been called.
2244 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2245 int p_index, unsigned int p_hash,
2246 InstanceKlass* k,
2247 Handle class_loader,
2248 TRAPS) {
2249 // Compile_lock prevents systemDictionary updates during compilations
2250 assert_locked_or_safepoint(Compile_lock);
2251 Symbol* name = k->name();
2252 ClassLoaderData *loader_data = class_loader_data(class_loader);
2253
2254 {
2255 MutexLocker mu1(SystemDictionary_lock, THREAD);
2256
2257 // See whether biased locking is enabled and if so set it for this
2258 // klass.
2259 // Note that this must be done past the last potential blocking
2260 // point / safepoint. We enable biased locking lazily using a
2261 // VM_Operation to iterate the SystemDictionary and installing the
2262 // biasable mark word into each InstanceKlass's prototype header.
2263 // To avoid race conditions where we accidentally miss enabling the
2264 // optimization for one class in the process of being added to the
2265 // dictionary, we must not safepoint after the test of
2266 // BiasedLocking::enabled().
2267 if (UseBiasedLocking && BiasedLocking::enabled()) {
2268 // Set biased locking bit for all loaded classes; it will be
2269 // cleared if revocation occurs too often for this type
2270 // NOTE that we must only do this when the class is initally
2271 // defined, not each time it is referenced from a new class loader
2272 if (k->class_loader() == class_loader()) {
2273 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2274 }
2275 }
2276
2277 // Make a new system dictionary entry.
2278 InstanceKlass* sd_check = find_class(d_index, d_hash, name, loader_data);
2279 if (sd_check == NULL) {
2280 dictionary()->add_klass(name, loader_data, k);
2281 notice_modification();
2282 }
2283 #ifdef ASSERT
2284 sd_check = find_class(d_index, d_hash, name, loader_data);
2285 assert (sd_check != NULL, "should have entry in system dictionary");
2286 // Note: there may be a placeholder entry: for circularity testing
2287 // or for parallel defines
2288 #endif
2289 SystemDictionary_lock->notify_all();
2290 }
2291 }
2292
2293
2294 // Try to find a class name using the loader constraints. The
2295 // loader constraints might know about a class that isn't fully loaded
2296 // yet and these will be ignored.
2297 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2298 Symbol* class_name, Handle class_loader, TRAPS) {
2299
2300 // First see if it has been loaded directly.
2301 // Force the protection domain to be null. (This removes protection checks.)
2302 Handle no_protection_domain;
2303 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2304 no_protection_domain, CHECK_NULL);
2305 if (klass != NULL)
2306 return klass;
2307
2308 // Now look to see if it has been loaded elsewhere, and is subject to
2309 // a loader constraint that would require this loader to return the
2310 // klass that is already loaded.
2311 if (FieldType::is_array(class_name)) {
2312 // For array classes, their Klass*s are not kept in the
2313 // constraint table. The element Klass*s are.
2314 FieldArrayInfo fd;
2315 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2316 if (t != T_OBJECT) {
2317 klass = Universe::typeArrayKlassObj(t);
2318 } else {
2319 MutexLocker mu(SystemDictionary_lock, THREAD);
2320 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2321 }
2322 // If element class already loaded, allocate array klass
2323 if (klass != NULL) {
2324 klass = klass->array_klass_or_null(fd.dimension());
2325 }
2326 } else {
2327 MutexLocker mu(SystemDictionary_lock, THREAD);
2328 // Non-array classes are easy: simply check the constraint table.
2329 klass = constraints()->find_constrained_klass(class_name, class_loader);
2330 }
2331
2332 return klass;
2333 }
2334
2335
2336 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2337 Handle class_loader1,
2338 Handle class_loader2,
2339 Thread* THREAD) {
2340 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2341 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2342
2343 Symbol* constraint_name = NULL;
2344 if (!FieldType::is_array(class_name)) {
2345 constraint_name = class_name;
2346 } else {
2347 // For array classes, their Klass*s are not kept in the
2348 // constraint table. The element classes are.
2349 FieldArrayInfo fd;
2350 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2351 // primitive types always pass
2352 if (t != T_OBJECT) {
2353 return true;
2354 } else {
2355 constraint_name = fd.object_key();
2356 }
2357 }
2358 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2359 int d_index1 = dictionary()->hash_to_index(d_hash1);
2360
2361 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2362 int d_index2 = dictionary()->hash_to_index(d_hash2);
2363 {
2364 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2365
2366 // Better never do a GC while we're holding these oops
2367 NoSafepointVerifier nosafepoint;
2368
2369 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2370 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2371 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2372 klass2, class_loader2);
2373 }
2374 }
2375
2376 // Add entry to resolution error table to record the error when the first
2377 // attempt to resolve a reference to a class has failed.
2378 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2379 Symbol* error, Symbol* message) {
2380 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2381 int index = resolution_errors()->hash_to_index(hash);
2382 {
2383 MutexLocker ml(SystemDictionary_lock, Thread::current());
2384 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2385 }
2386 }
2387
2388 // Delete a resolution error for RedefineClasses for a constant pool is going away
2389 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2390 resolution_errors()->delete_entry(pool);
2391 }
2392
2393 // Lookup resolution error table. Returns error if found, otherwise NULL.
2394 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2395 Symbol** message) {
2396 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2397 int index = resolution_errors()->hash_to_index(hash);
2398 {
2399 MutexLocker ml(SystemDictionary_lock, Thread::current());
2400 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2401 if (entry != NULL) {
2402 *message = entry->message();
2403 return entry->error();
2404 } else {
2405 return NULL;
2406 }
2407 }
2408 }
2409
2410
2411 // Signature constraints ensure that callers and callees agree about
2412 // the meaning of type names in their signatures. This routine is the
2413 // intake for constraints. It collects them from several places:
2414 //
2415 // * LinkResolver::resolve_method (if check_access is true) requires
2416 // that the resolving class (the caller) and the defining class of
2417 // the resolved method (the callee) agree on each type in the
2418 // method's signature.
2419 //
2420 // * LinkResolver::resolve_interface_method performs exactly the same
2421 // checks.
2422 //
2423 // * LinkResolver::resolve_field requires that the constant pool
2424 // attempting to link to a field agree with the field's defining
2425 // class about the type of the field signature.
2426 //
2427 // * klassVtable::initialize_vtable requires that, when a class
2428 // overrides a vtable entry allocated by a superclass, that the
2429 // overriding method (i.e., the callee) agree with the superclass
2430 // on each type in the method's signature.
2431 //
2432 // * klassItable::initialize_itable requires that, when a class fills
2433 // in its itables, for each non-abstract method installed in an
2434 // itable, the method (i.e., the callee) agree with the interface
2435 // on each type in the method's signature.
2436 //
2437 // All those methods have a boolean (check_access, checkconstraints)
2438 // which turns off the checks. This is used from specialized contexts
2439 // such as bootstrapping, dumping, and debugging.
2440 //
2441 // No direct constraint is placed between the class and its
2442 // supertypes. Constraints are only placed along linked relations
2443 // between callers and callees. When a method overrides or implements
2444 // an abstract method in a supertype (superclass or interface), the
2445 // constraints are placed as if the supertype were the caller to the
2446 // overriding method. (This works well, since callers to the
2447 // supertype have already established agreement between themselves and
2448 // the supertype.) As a result of all this, a class can disagree with
2449 // its supertype about the meaning of a type name, as long as that
2450 // class neither calls a relevant method of the supertype, nor is
2451 // called (perhaps via an override) from the supertype.
2452 //
2453 //
2454 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2455 //
2456 // Make sure all class components (including arrays) in the given
2457 // signature will be resolved to the same class in both loaders.
2458 // Returns the name of the type that failed a loader constraint check, or
2459 // NULL if no constraint failed. No exception except OOME is thrown.
2460 // Arrays are not added to the loader constraint table, their elements are.
2461 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2462 Handle loader1, Handle loader2,
2463 bool is_method, TRAPS) {
2464 // Nothing to do if loaders are the same.
2465 if (loader1() == loader2()) {
2466 return NULL;
2467 }
2468
2469 SignatureStream sig_strm(signature, is_method);
2470 while (!sig_strm.is_done()) {
2471 if (sig_strm.is_object()) {
2472 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2473 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2474 return sig;
2475 }
2476 }
2477 sig_strm.next();
2478 }
2479 return NULL;
2480 }
2481
2482
2483 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2484 Symbol* signature,
2485 TRAPS) {
2486 methodHandle empty;
2487 assert(MethodHandles::is_signature_polymorphic(iid) &&
2488 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2489 iid != vmIntrinsics::_invokeGeneric,
2490 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2491
2492 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2493 int index = invoke_method_table()->hash_to_index(hash);
2494 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2495 methodHandle m;
2496 if (spe == NULL || spe->method() == NULL) {
2497 spe = NULL;
2498 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2499 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2500 if (!Arguments::is_interpreter_only()) {
2501 // Generate a compiled form of the MH intrinsic.
2502 AdapterHandlerLibrary::create_native_wrapper(m);
2503 // Check if have the compiled code.
2504 if (!m->has_compiled_code()) {
2505 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2506 "Out of space in CodeCache for method handle intrinsic", empty);
2507 }
2508 }
2509 // Now grab the lock. We might have to throw away the new method,
2510 // if a racing thread has managed to install one at the same time.
2511 {
2512 MutexLocker ml(SystemDictionary_lock, THREAD);
2513 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2514 if (spe == NULL)
2515 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2516 if (spe->method() == NULL)
2517 spe->set_method(m());
2518 }
2519 }
2520
2521 assert(spe != NULL && spe->method() != NULL, "");
2522 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2523 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2524 "MH intrinsic invariant");
2525 return spe->method();
2526 }
2527
2528 // Helper for unpacking the return value from linkMethod and linkCallSite.
2529 static methodHandle unpack_method_and_appendix(Handle mname,
2530 Klass* accessing_klass,
2531 objArrayHandle appendix_box,
2532 Handle* appendix_result,
2533 TRAPS) {
2534 methodHandle empty;
2535 if (mname.not_null()) {
2536 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2537 if (vmtarget != NULL && vmtarget->is_method()) {
2538 Method* m = (Method*)vmtarget;
2539 oop appendix = appendix_box->obj_at(0);
2540 if (TraceMethodHandles) {
2541 #ifndef PRODUCT
2542 ttyLocker ttyl;
2543 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2544 m->print();
2545 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2546 tty->cr();
2547 #endif //PRODUCT
2548 }
2549 (*appendix_result) = Handle(THREAD, appendix);
2550 // the target is stored in the cpCache and if a reference to this
2551 // MethodName is dropped we need a way to make sure the
2552 // class_loader containing this method is kept alive.
2553 // FIXME: the appendix might also preserve this dependency.
2554 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2555 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2556 return methodHandle(THREAD, m);
2557 }
2558 }
2559 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2560 return empty;
2561 }
2562
2563 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2564 Symbol* name,
2565 Symbol* signature,
2566 Klass* accessing_klass,
2567 Handle *appendix_result,
2568 Handle *method_type_result,
2569 TRAPS) {
2570 methodHandle empty;
2571 assert(THREAD->can_call_java() ,"");
2572 Handle method_type =
2573 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2574
2575 int ref_kind = JVM_REF_invokeVirtual;
2576 oop name_oop = StringTable::intern(name, CHECK_(empty));
2577 Handle name_str (THREAD, name_oop);
2578 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2579 assert(appendix_box->obj_at(0) == NULL, "");
2580
2581 // This should not happen. JDK code should take care of that.
2582 if (accessing_klass == NULL || method_type.is_null()) {
2583 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2584 }
2585
2586 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2587 JavaCallArguments args;
2588 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2589 args.push_int(ref_kind);
2590 args.push_oop(Handle(THREAD, klass->java_mirror()));
2591 args.push_oop(name_str);
2592 args.push_oop(method_type);
2593 args.push_oop(appendix_box);
2594 JavaValue result(T_OBJECT);
2595 JavaCalls::call_static(&result,
2596 SystemDictionary::MethodHandleNatives_klass(),
2597 vmSymbols::linkMethod_name(),
2598 vmSymbols::linkMethod_signature(),
2599 &args, CHECK_(empty));
2600 Handle mname(THREAD, (oop) result.get_jobject());
2601 (*method_type_result) = method_type;
2602 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2603 }
2604
2605 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2606 // We must ensure that all class loaders everywhere will reach this class, for any client.
2607 // This is a safe bet for public classes in java.lang, such as Object and String.
2608 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2609 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2610 static bool is_always_visible_class(oop mirror) {
2611 Klass* klass = java_lang_Class::as_Klass(mirror);
2612 if (klass->is_objArray_klass()) {
2613 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2614 }
2615 if (klass->is_typeArray_klass()) {
2616 return true; // primitive array
2617 }
2618 assert(klass->is_instance_klass(), "%s", klass->external_name());
2619 return klass->is_public() &&
2620 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2621 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2622 }
2623
2624 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2625 // signature, as interpreted relative to the given class loader.
2626 // Because of class loader constraints, all method handle usage must be
2627 // consistent with this loader.
2628 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2629 Klass* accessing_klass,
2630 TRAPS) {
2631 Handle empty;
2632 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2633 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2634 int index = invoke_method_table()->hash_to_index(hash);
2635 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2636 if (spe != NULL && spe->method_type() != NULL) {
2637 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2638 return Handle(THREAD, spe->method_type());
2639 } else if (!THREAD->can_call_java()) {
2640 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2641 return Handle(); // do not attempt from within compiler, unless it was cached
2642 }
2643
2644 Handle class_loader, protection_domain;
2645 if (accessing_klass != NULL) {
2646 class_loader = Handle(THREAD, accessing_klass->class_loader());
2647 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2648 }
2649 bool can_be_cached = true;
2650 int npts = ArgumentCount(signature).size();
2651 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2652 int arg = 0;
2653 Handle rt; // the return type from the signature
2654 ResourceMark rm(THREAD);
2655 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2656 oop mirror = NULL;
2657 if (can_be_cached) {
2658 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2659 mirror = ss.as_java_mirror(Handle(), Handle(),
2660 SignatureStream::ReturnNull, CHECK_(empty));
2661 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2662 // Fall back to accessing_klass context.
2663 can_be_cached = false;
2664 }
2665 }
2666 if (!can_be_cached) {
2667 // Resolve, throwing a real error if it doesn't work.
2668 mirror = ss.as_java_mirror(class_loader, protection_domain,
2669 SignatureStream::NCDFError, CHECK_(empty));
2670 }
2671 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2672 if (ss.at_return_type())
2673 rt = Handle(THREAD, mirror);
2674 else
2675 pts->obj_at_put(arg++, mirror);
2676
2677 // Check accessibility.
2678 if (ss.is_object() && accessing_klass != NULL) {
2679 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2680 mirror = NULL; // safety
2681 // Emulate ConstantPool::verify_constant_pool_resolve.
2682 if (sel_klass->is_objArray_klass())
2683 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2684 if (sel_klass->is_instance_klass()) {
2685 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2686 }
2687 }
2688 }
2689 assert(arg == npts, "");
2690
2691 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2692 JavaCallArguments args(Handle(THREAD, rt()));
2693 args.push_oop(pts);
2694 JavaValue result(T_OBJECT);
2695 JavaCalls::call_static(&result,
2696 SystemDictionary::MethodHandleNatives_klass(),
2697 vmSymbols::findMethodHandleType_name(),
2698 vmSymbols::findMethodHandleType_signature(),
2699 &args, CHECK_(empty));
2700 Handle method_type(THREAD, (oop) result.get_jobject());
2701
2702 if (can_be_cached) {
2703 // We can cache this MethodType inside the JVM.
2704 MutexLocker ml(SystemDictionary_lock, THREAD);
2705 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2706 if (spe == NULL)
2707 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2708 if (spe->method_type() == NULL) {
2709 spe->set_method_type(method_type());
2710 }
2711 }
2712
2713 // report back to the caller with the MethodType
2714 return method_type;
2715 }
2716
2717 // Ask Java code to find or construct a method handle constant.
2718 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2719 int ref_kind, //e.g., JVM_REF_invokeVirtual
2720 Klass* callee,
2721 Symbol* name_sym,
2722 Symbol* signature,
2723 TRAPS) {
2724 Handle empty;
2725 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2726 Handle type;
2727 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2728 type = find_method_handle_type(signature, caller, CHECK_(empty));
2729 } else if (caller == NULL) {
2730 // This should not happen. JDK code should take care of that.
2731 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2732 } else {
2733 ResourceMark rm(THREAD);
2734 SignatureStream ss(signature, false);
2735 if (!ss.is_done()) {
2736 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2737 Handle(THREAD, caller->protection_domain()),
2738 SignatureStream::NCDFError, CHECK_(empty));
2739 type = Handle(THREAD, mirror);
2740 ss.next();
2741 if (!ss.is_done()) type = Handle(); // error!
2742 }
2743 }
2744 if (type.is_null()) {
2745 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2746 }
2747
2748 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2749 JavaCallArguments args;
2750 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2751 args.push_int(ref_kind);
2752 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2753 args.push_oop(name);
2754 args.push_oop(type);
2755 JavaValue result(T_OBJECT);
2756 JavaCalls::call_static(&result,
2757 SystemDictionary::MethodHandleNatives_klass(),
2758 vmSymbols::linkMethodHandleConstant_name(),
2759 vmSymbols::linkMethodHandleConstant_signature(),
2760 &args, CHECK_(empty));
2761 return Handle(THREAD, (oop) result.get_jobject());
2762 }
2763
2764 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2765 // name and signature, as interpreted relative to the given class loader.
2766 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2767 Handle bootstrap_specifier,
2768 Symbol* name,
2769 Symbol* type,
2770 Handle *appendix_result,
2771 Handle *method_type_result,
2772 TRAPS) {
2773 methodHandle empty;
2774 Handle bsm, info;
2775 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2776 bsm = bootstrap_specifier;
2777 } else {
2778 assert(bootstrap_specifier->is_objArray(), "");
2779 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2780 int len = args->length();
2781 assert(len >= 1, "");
2782 bsm = Handle(THREAD, args->obj_at(0));
2783 if (len > 1) {
2784 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2785 for (int i = 1; i < len; i++)
2786 args1->obj_at_put(i-1, args->obj_at(i));
2787 info = Handle(THREAD, args1);
2788 }
2789 }
2790 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2791 "caller must supply a valid BSM");
2792
2793 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2794 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2795
2796 // This should not happen. JDK code should take care of that.
2797 if (caller == NULL || method_type.is_null()) {
2798 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2799 }
2800
2801 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2802 assert(appendix_box->obj_at(0) == NULL, "");
2803
2804 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2805 JavaCallArguments args;
2806 args.push_oop(Handle(THREAD, caller->java_mirror()));
2807 args.push_oop(bsm);
2808 args.push_oop(method_name);
2809 args.push_oop(method_type);
2810 args.push_oop(info);
2811 args.push_oop(appendix_box);
2812 JavaValue result(T_OBJECT);
2813 JavaCalls::call_static(&result,
2814 SystemDictionary::MethodHandleNatives_klass(),
2815 vmSymbols::linkCallSite_name(),
2816 vmSymbols::linkCallSite_signature(),
2817 &args, CHECK_(empty));
2818 Handle mname(THREAD, (oop) result.get_jobject());
2819 (*method_type_result) = method_type;
2820 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2821 }
2822
2823 // Since the identity hash code for symbols changes when the symbols are
2824 // moved from the regular perm gen (hash in the mark word) to the shared
2825 // spaces (hash is the address), the classes loaded into the dictionary
2826 // may be in the wrong buckets.
2827
2828 void SystemDictionary::reorder_dictionary() {
2829 dictionary()->reorder_dictionary();
2830 }
2831
2832
2833 void SystemDictionary::copy_buckets(char** top, char* end) {
2834 dictionary()->copy_buckets(top, end);
2835 }
2836
2837
2838 void SystemDictionary::copy_table(char** top, char* end) {
2839 dictionary()->copy_table(top, end);
2840 }
2841
2842
2843 void SystemDictionary::reverse() {
2844 dictionary()->reverse();
2845 }
2846
2847 int SystemDictionary::number_of_classes() {
2848 return dictionary()->number_of_entries();
2849 }
2850
2851
2852 // ----------------------------------------------------------------------------
2853 void SystemDictionary::print_shared(bool details) {
2854 shared_dictionary()->print(details);
2855 }
2856
2857 void SystemDictionary::print(bool details) {
2858 dictionary()->print(details);
2859
2860 // Placeholders
2861 GCMutexLocker mu(SystemDictionary_lock);
2862 placeholders()->print();
2863
2864 // loader constraints - print under SD_lock
2865 constraints()->print();
2866 }
2867
2868
2869 void SystemDictionary::verify() {
2870 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2871 guarantee(constraints() != NULL,
2872 "Verify of loader constraints failed");
2873 guarantee(dictionary()->number_of_entries() >= 0 &&
2874 placeholders()->number_of_entries() >= 0,
2875 "Verify of system dictionary failed");
2876
2877 // Verify dictionary
2878 dictionary()->verify();
2879
2880 GCMutexLocker mu(SystemDictionary_lock);
2881 placeholders()->verify();
2882
2883 // Verify constraint table
2884 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2885 constraints()->verify(dictionary(), placeholders());
2886 }
2887
2888 // caller needs ResourceMark
2889 const char* SystemDictionary::loader_name(const oop loader) {
2890 return ((loader) == NULL ? "<bootloader>" :
2891 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2892 }
2893
2894 // caller needs ResourceMark
2895 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2896 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2897 SystemDictionary::loader_name(loader_data->class_loader()));
2898 }