1 /*
2 * Copyright (c) 1997, 2016, 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 "classfile/classFileParser.hpp"
27 #include "classfile/classFileStream.hpp"
28 #include "classfile/classLoader.hpp"
29 #include "classfile/classLoaderData.inline.hpp"
30 #include "classfile/classLoaderExt.hpp"
31 #include "classfile/dictionary.hpp"
32 #include "classfile/javaClasses.inline.hpp"
33 #include "classfile/klassFactory.hpp"
34 #include "classfile/loaderConstraints.hpp"
35 #include "classfile/packageEntry.hpp"
36 #include "classfile/placeholders.hpp"
37 #include "classfile/resolutionErrors.hpp"
38 #include "classfile/stringTable.hpp"
39 #include "classfile/systemDictionary.hpp"
40 #include "classfile/vmSymbols.hpp"
41 #include "code/codeCache.hpp"
42 #include "compiler/compileBroker.hpp"
43 #include "gc/shared/gcLocker.hpp"
44 #include "interpreter/bytecodeStream.hpp"
45 #include "interpreter/interpreter.hpp"
46 #include "memory/filemap.hpp"
47 #include "memory/oopFactory.hpp"
48 #include "memory/resourceArea.hpp"
49 #include "oops/instanceKlass.hpp"
50 #include "oops/instanceRefKlass.hpp"
51 #include "oops/klass.inline.hpp"
52 #include "oops/methodData.hpp"
53 #include "oops/objArrayKlass.hpp"
54 #include "oops/objArrayOop.inline.hpp"
55 #include "oops/oop.inline.hpp"
56 #include "oops/symbol.hpp"
57 #include "oops/typeArrayKlass.hpp"
58 #include "prims/jvmtiEnvBase.hpp"
59 #include "prims/methodHandles.hpp"
60 #include "runtime/arguments.hpp"
61 #include "runtime/biasedLocking.hpp"
62 #include "runtime/fieldType.hpp"
63 #include "runtime/handles.inline.hpp"
64 #include "runtime/java.hpp"
65 #include "runtime/javaCalls.hpp"
66 #include "runtime/mutexLocker.hpp"
67 #include "runtime/orderAccess.inline.hpp"
68 #include "runtime/signature.hpp"
69 #include "services/classLoadingService.hpp"
70 #include "services/threadService.hpp"
71 #include "trace/traceMacros.hpp"
72 #include "utilities/macros.hpp"
73 #include "utilities/ticks.hpp"
74 #if INCLUDE_CDS
75 #include "classfile/sharedClassUtil.hpp"
76 #include "classfile/systemDictionaryShared.hpp"
77 #endif
78 #if INCLUDE_JVMCI
79 #include "jvmci/jvmciRuntime.hpp"
80 #endif
81 #if INCLUDE_TRACE
82 #include "trace/tracing.hpp"
83 #endif
84
85 Dictionary* SystemDictionary::_dictionary = NULL;
86 PlaceholderTable* SystemDictionary::_placeholders = NULL;
87 Dictionary* SystemDictionary::_shared_dictionary = NULL;
88 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
89 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
90 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
91
92
93 int SystemDictionary::_number_of_modifications = 0;
94 int SystemDictionary::_sdgeneration = 0;
95 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
96 20201,40423,99991};
97
98 oop SystemDictionary::_system_loader_lock_obj = NULL;
99
100 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
101 = { NULL /*, NULL...*/ };
102
103 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
104
105 oop SystemDictionary::_java_system_loader = NULL;
106
107 bool SystemDictionary::_has_loadClassInternal = false;
108 bool SystemDictionary::_has_checkPackageAccess = false;
109
110 // lazily initialized klass variables
111 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
112
113
114 // ----------------------------------------------------------------------------
115 // Java-level SystemLoader
116
117 oop SystemDictionary::java_system_loader() {
118 return _java_system_loader;
119 }
120
121 void SystemDictionary::compute_java_system_loader(TRAPS) {
122 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
123 JavaValue result(T_OBJECT);
124 JavaCalls::call_static(&result,
125 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
126 vmSymbols::getSystemClassLoader_name(),
127 vmSymbols::void_classloader_signature(),
128 CHECK);
129
130 _java_system_loader = (oop)result.get_jobject();
131
132 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
133 }
134
135
136 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
137 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
138 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
139 }
140
141 // ----------------------------------------------------------------------------
142 // Parallel class loading check
143
144 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
145 if (UnsyncloadClass || class_loader.is_null()) return true;
146 if (AlwaysLockClassLoader) return false;
147 return java_lang_ClassLoader::parallelCapable(class_loader());
148 }
149 // ----------------------------------------------------------------------------
150 // ParallelDefineClass flag does not apply to bootclass loader
151 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
152 if (class_loader.is_null()) return false;
153 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
154 return true;
155 }
156 return false;
157 }
158
159 // Returns true if the passed class loader is the builtin application class loader
160 // or a custom system class loader. A customer system class loader can be
161 // specified via -Djava.system.class.loader.
162 bool SystemDictionary::is_system_class_loader(Handle class_loader) {
163 if (class_loader.is_null()) {
164 return false;
165 }
166 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
167 class_loader() == _java_system_loader);
168 }
169
170 // Returns true if the passed class loader is the platform class loader.
171 bool SystemDictionary::is_platform_class_loader(Handle class_loader) {
172 if (class_loader.is_null()) {
173 return false;
174 }
175 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
176 }
177
178 // ----------------------------------------------------------------------------
179 // Resolving of classes
180
181 // Forwards to resolve_or_null
182
183 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
184 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
185 if (HAS_PENDING_EXCEPTION || klass == NULL) {
186 KlassHandle k_h(THREAD, klass);
187 // can return a null klass
188 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
189 }
190 return klass;
191 }
192
193 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
194 bool throw_error,
195 KlassHandle klass_h, 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_h() == 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_h() == 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*)klass_h();
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 KlassHandle superk_h(THREAD, superk);
405
406 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
407 // It is no longer necessary to keep the placeholder table alive until update_dictionary
408 // or error. GC used to walk the placeholder table as strong roots.
409 // The instanceKlass is kept alive because the class loader is on the stack,
410 // which keeps the loader_data alive, as well as all instanceKlasses in
411 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
412 {
413 MutexLocker mu(SystemDictionary_lock, THREAD);
414 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
415 SystemDictionary_lock->notify_all();
416 }
417 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
418 // can null superk
419 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
420 }
421
422 return superk_h();
423 }
424
425 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
426 Handle class_loader,
427 Handle protection_domain,
428 TRAPS) {
429 if(!has_checkPackageAccess()) return;
430
431 // Now we have to call back to java to check if the initating class has access
432 JavaValue result(T_VOID);
433 if (log_is_enabled(Debug, protectiondomain)) {
434 ResourceMark rm;
435 // Print out trace information
436 outputStream* log = Log(protectiondomain)::debug_stream();
437 log->print_cr("Checking package access");
438 log->print("class loader: "); class_loader()->print_value_on(log);
439 log->print(" protection domain: "); protection_domain()->print_value_on(log);
440 log->print(" loading: "); klass()->print_value_on(log);
441 log->cr();
442 }
443
444 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
445 JavaCalls::call_special(&result,
446 class_loader,
447 system_loader,
448 vmSymbols::checkPackageAccess_name(),
449 vmSymbols::class_protectiondomain_signature(),
450 Handle(THREAD, klass->java_mirror()),
451 protection_domain,
452 THREAD);
453
454 if (HAS_PENDING_EXCEPTION) {
455 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
456 } else {
457 log_debug(protectiondomain)("granted");
458 }
459
460 if (HAS_PENDING_EXCEPTION) return;
461
462 // If no exception has been thrown, we have validated the protection domain
463 // Insert the protection domain of the initiating class into the set.
464 {
465 // We recalculate the entry here -- we've called out to java since
466 // the last time it was calculated.
467 ClassLoaderData* loader_data = class_loader_data(class_loader);
468
469 Symbol* kn = klass->name();
470 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
471 int d_index = dictionary()->hash_to_index(d_hash);
472
473 MutexLocker mu(SystemDictionary_lock, THREAD);
474 {
475 // Note that we have an entry, and entries can be deleted only during GC,
476 // so we cannot allow GC to occur while we're holding this entry.
477
478 // We're using a NoSafepointVerifier to catch any place where we
479 // might potentially do a GC at all.
480 // Dictionary::do_unloading() asserts that classes in SD are only
481 // unloaded at a safepoint. Anonymous classes are not in SD.
482 NoSafepointVerifier nosafepoint;
483 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
484 protection_domain, THREAD);
485 }
486 }
487 }
488
489 // We only get here if this thread finds that another thread
490 // has already claimed the placeholder token for the current operation,
491 // but that other thread either never owned or gave up the
492 // object lock
493 // Waits on SystemDictionary_lock to indicate placeholder table updated
494 // On return, caller must recheck placeholder table state
495 //
496 // We only get here if
497 // 1) custom classLoader, i.e. not bootstrap classloader
498 // 2) UnsyncloadClass not set
499 // 3) custom classLoader has broken the class loader objectLock
500 // so another thread got here in parallel
501 //
502 // lockObject must be held.
503 // Complicated dance due to lock ordering:
504 // Must first release the classloader object lock to
505 // allow initial definer to complete the class definition
506 // and to avoid deadlock
507 // Reclaim classloader lock object with same original recursion count
508 // Must release SystemDictionary_lock after notify, since
509 // class loader lock must be claimed before SystemDictionary_lock
510 // to prevent deadlocks
511 //
512 // The notify allows applications that did an untimed wait() on
513 // the classloader object lock to not hang.
514 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
515 assert_lock_strong(SystemDictionary_lock);
516
517 bool calledholdinglock
518 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
519 assert(calledholdinglock,"must hold lock for notify");
520 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
521 ObjectSynchronizer::notifyall(lockObject, THREAD);
522 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
523 SystemDictionary_lock->wait();
524 SystemDictionary_lock->unlock();
525 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
526 SystemDictionary_lock->lock();
527 }
528
529 // If the class in is in the placeholder table, class loading is in progress
530 // For cases where the application changes threads to load classes, it
531 // is critical to ClassCircularity detection that we try loading
532 // the superclass on the same thread internally, so we do parallel
533 // super class loading here.
534 // This also is critical in cases where the original thread gets stalled
535 // even in non-circularity situations.
536 // Note: must call resolve_super_or_fail even if null super -
537 // to force placeholder entry creation for this class for circularity detection
538 // Caller must check for pending exception
539 // Returns non-null Klass* if other thread has completed load
540 // and we are done,
541 // If return null Klass* and no pending exception, the caller must load the class
542 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
543 Symbol* name, Symbol* superclassname, Handle class_loader,
544 Handle protection_domain, Handle lockObject, TRAPS) {
545
546 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
547 ClassLoaderData* loader_data = class_loader_data(class_loader);
548 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
549 int d_index = dictionary()->hash_to_index(d_hash);
550 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
551 int p_index = placeholders()->hash_to_index(p_hash);
552
553 // superk is not used, resolve_super called for circularity check only
554 // This code is reached in two situations. One if this thread
555 // is loading the same class twice (e.g. ClassCircularity, or
556 // java.lang.instrument).
557 // The second is if another thread started the resolve_super first
558 // and has not yet finished.
559 // In both cases the original caller will clean up the placeholder
560 // entry on error.
561 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
562 superclassname,
563 class_loader,
564 protection_domain,
565 true,
566 CHECK_(nh));
567
568 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
569 // Serial class loaders and bootstrap classloader do wait for superclass loads
570 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
571 MutexLocker mu(SystemDictionary_lock, THREAD);
572 // Check if classloading completed while we were loading superclass or waiting
573 Klass* check = find_class(d_index, d_hash, name, loader_data);
574 if (check != NULL) {
575 // Klass is already loaded, so just return it
576 return(instanceKlassHandle(THREAD, check));
577 } else {
578 return nh;
579 }
580 }
581
582 // must loop to both handle other placeholder updates
583 // and spurious notifications
584 bool super_load_in_progress = true;
585 PlaceholderEntry* placeholder;
586 while (super_load_in_progress) {
587 MutexLocker mu(SystemDictionary_lock, THREAD);
588 // Check if classloading completed while we were loading superclass or waiting
589 Klass* check = find_class(d_index, d_hash, name, loader_data);
590 if (check != NULL) {
591 // Klass is already loaded, so just return it
592 return(instanceKlassHandle(THREAD, check));
593 } else {
594 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
595 if (placeholder && placeholder->super_load_in_progress() ){
596 // Before UnsyncloadClass:
597 // We only get here if the application has released the
598 // classloader lock when another thread was in the middle of loading a
599 // superclass/superinterface for this class, and now
600 // this thread is also trying to load this class.
601 // To minimize surprises, the first thread that started to
602 // load a class should be the one to complete the loading
603 // with the classfile it initially expected.
604 // This logic has the current thread wait once it has done
605 // all the superclass/superinterface loading it can, until
606 // the original thread completes the class loading or fails
607 // If it completes we will use the resulting InstanceKlass
608 // which we will find below in the systemDictionary.
609 // We also get here for parallel bootstrap classloader
610 if (class_loader.is_null()) {
611 SystemDictionary_lock->wait();
612 } else {
613 double_lock_wait(lockObject, THREAD);
614 }
615 } else {
616 // If not in SD and not in PH, other thread's load must have failed
617 super_load_in_progress = false;
618 }
619 }
620 }
621 return (nh);
622 }
623
624 static void post_class_load_event(const Ticks& start_time,
625 instanceKlassHandle k,
626 const ClassLoaderData* init_cld) {
627 #if INCLUDE_TRACE
628 EventClassLoad event(UNTIMED);
629 if (event.should_commit()) {
630 event.set_starttime(start_time);
631 event.set_loadedClass(k());
632 event.set_definingClassLoader(k->class_loader_data());
633 event.set_initiatingClassLoader(init_cld);
634 event.commit();
635 }
636 #endif // INCLUDE_TRACE
637 }
638
639 static void class_define_event(instanceKlassHandle k,
640 const ClassLoaderData* def_cld) {
641 #if INCLUDE_TRACE
642 EventClassDefine event;
643 if (event.should_commit()) {
644 event.set_definedClass(k());
645 event.set_definingClassLoader(def_cld);
646 event.commit();
647 }
648 #endif // INCLUDE_TRACE
649 }
650
651 // Be careful when modifying this code: once you have run
652 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
653 // you need to find_and_remove it before returning.
654 // So be careful to not exit with a CHECK_ macro betweeen these calls.
655 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
656 Handle class_loader,
657 Handle protection_domain,
658 TRAPS) {
659 assert(name != NULL && !FieldType::is_array(name) &&
660 !FieldType::is_obj(name), "invalid class name");
661
662 Ticks class_load_start_time = Ticks::now();
663
664 // Fix for 4474172; see evaluation for more details
665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
666 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
667
668 // Do lookup to see if class already exist and the protection domain
669 // has the right access
670 // This call uses find which checks protection domain already matches
671 // All subsequent calls use find_class, and set has_loaded_class so that
672 // before we return a result we call out to java to check for valid protection domain
673 // to allow returning the Klass* and add it to the pd_set if it is valid
674 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
675 int d_index = dictionary()->hash_to_index(d_hash);
676 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
677 protection_domain, THREAD);
678 if (probe != NULL) return probe;
679
680
681 // Non-bootstrap class loaders will call out to class loader and
682 // define via jvm/jni_DefineClass which will acquire the
683 // class loader object lock to protect against multiple threads
684 // defining the class in parallel by accident.
685 // This lock must be acquired here so the waiter will find
686 // any successful result in the SystemDictionary and not attempt
687 // the define
688 // ParallelCapable Classloaders and the bootstrap classloader,
689 // or all classloaders with UnsyncloadClass do not acquire lock here
690 bool DoObjectLock = true;
691 if (is_parallelCapable(class_loader)) {
692 DoObjectLock = false;
693 }
694
695 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
696 int p_index = placeholders()->hash_to_index(p_hash);
697
698 // Class is not in SystemDictionary so we have to do loading.
699 // Make sure we are synchronized on the class loader before we proceed
700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
701 check_loader_lock_contention(lockObject, THREAD);
702 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
703
704 // Check again (after locking) if class already exist in SystemDictionary
705 bool class_has_been_loaded = false;
706 bool super_load_in_progress = false;
707 bool havesupername = false;
708 instanceKlassHandle k;
709 PlaceholderEntry* placeholder;
710 Symbol* superclassname = NULL;
711
712 {
713 MutexLocker mu(SystemDictionary_lock, THREAD);
714 Klass* check = find_class(d_index, d_hash, name, loader_data);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 class_has_been_loaded = true;
718 k = instanceKlassHandle(THREAD, check);
719 } else {
720 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
721 if (placeholder && placeholder->super_load_in_progress()) {
722 super_load_in_progress = true;
723 if (placeholder->havesupername() == true) {
724 superclassname = placeholder->supername();
725 havesupername = true;
726 }
727 }
728 }
729 }
730
731 // If the class is in the placeholder table, class loading is in progress
732 if (super_load_in_progress && havesupername==true) {
733 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
734 class_loader, protection_domain, lockObject, THREAD);
735 if (HAS_PENDING_EXCEPTION) {
736 return NULL;
737 }
738 if (!k.is_null()) {
739 class_has_been_loaded = true;
740 }
741 }
742
743 bool throw_circularity_error = false;
744 if (!class_has_been_loaded) {
745 bool load_instance_added = false;
746
747 // add placeholder entry to record loading instance class
748 // Five cases:
749 // All cases need to prevent modifying bootclasssearchpath
750 // in parallel with a classload of same classname
751 // Redefineclasses uses existence of the placeholder for the duration
752 // of the class load to prevent concurrent redefinition of not completely
753 // defined classes.
754 // case 1. traditional classloaders that rely on the classloader object lock
755 // - no other need for LOAD_INSTANCE
756 // case 2. traditional classloaders that break the classloader object lock
757 // as a deadlock workaround. Detection of this case requires that
758 // this check is done while holding the classloader object lock,
759 // and that lock is still held when calling classloader's loadClass.
760 // For these classloaders, we ensure that the first requestor
761 // completes the load and other requestors wait for completion.
762 // case 3. UnsyncloadClass - don't use objectLocker
763 // With this flag, we allow parallel classloading of a
764 // class/classloader pair
765 // case4. Bootstrap classloader - don't own objectLocker
766 // This classloader supports parallelism at the classloader level,
767 // but only allows a single load of a class/classloader pair.
768 // No performance benefit and no deadlock issues.
769 // case 5. parallelCapable user level classloaders - without objectLocker
770 // Allow parallel classloading of a class/classloader pair
771
772 {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
776 if (oldprobe) {
777 // only need check_seen_thread once, not on each loop
778 // 6341374 java/lang/Instrument with -Xcomp
779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
780 throw_circularity_error = true;
781 } else {
782 // case 1: traditional: should never see load_in_progress.
783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
784
785 // case 4: bootstrap classloader: prevent futile classloading,
786 // wait on first requestor
787 if (class_loader.is_null()) {
788 SystemDictionary_lock->wait();
789 } else {
790 // case 2: traditional with broken classloader lock. wait on first
791 // requestor.
792 double_lock_wait(lockObject, THREAD);
793 }
794 // Check if classloading completed while we were waiting
795 Klass* check = find_class(d_index, d_hash, name, loader_data);
796 if (check != NULL) {
797 // Klass is already loaded, so just return it
798 k = instanceKlassHandle(THREAD, check);
799 class_has_been_loaded = true;
800 }
801 // check if other thread failed to load and cleaned up
802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
803 }
804 }
805 }
806 }
807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
808 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
809 // LOAD_INSTANCE in parallel
810
811 if (!throw_circularity_error && !class_has_been_loaded) {
812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
813 load_instance_added = true;
814 // For class loaders that do not acquire the classloader object lock,
815 // if they did not catch another thread holding LOAD_INSTANCE,
816 // need a check analogous to the acquire ObjectLocker/find_class
817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
818 // one final check if the load has already completed
819 // class loaders holding the ObjectLock shouldn't find the class here
820 Klass* check = find_class(d_index, d_hash, name, loader_data);
821 if (check != NULL) {
822 // Klass is already loaded, so return it after checking/adding protection domain
823 k = instanceKlassHandle(THREAD, check);
824 class_has_been_loaded = true;
825 }
826 }
827 }
828
829 // must throw error outside of owning lock
830 if (throw_circularity_error) {
831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
832 ResourceMark rm(THREAD);
833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
834 }
835
836 if (!class_has_been_loaded) {
837
838 // Do actual loading
839 k = load_instance_class(name, class_loader, THREAD);
840
841 // For UnsyncloadClass only
842 // If they got a linkageError, check if a parallel class load succeeded.
843 // If it did, then for bytecode resolution the specification requires
844 // that we return the same result we did for the other thread, i.e. the
845 // successfully loaded InstanceKlass
846 // Should not get here for classloaders that support parallelism
847 // with the new cleaner mechanism, even with AllowParallelDefineClass
848 // Bootstrap goes through here to allow for an extra guarantee check
849 if (UnsyncloadClass || (class_loader.is_null())) {
850 if (k.is_null() && HAS_PENDING_EXCEPTION
851 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
852 MutexLocker mu(SystemDictionary_lock, THREAD);
853 Klass* check = find_class(d_index, d_hash, name, loader_data);
854 if (check != NULL) {
855 // Klass is already loaded, so just use it
856 k = instanceKlassHandle(THREAD, check);
857 CLEAR_PENDING_EXCEPTION;
858 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
859 }
860 }
861 }
862
863 // If everything was OK (no exceptions, no null return value), and
864 // class_loader is NOT the defining loader, do a little more bookkeeping.
865 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
866 k->class_loader() != class_loader()) {
867
868 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
869
870 // Need to check for a PENDING_EXCEPTION again; check_constraints
871 // can throw and doesn't use the CHECK macro.
872 if (!HAS_PENDING_EXCEPTION) {
873 { // Grabbing the Compile_lock prevents systemDictionary updates
874 // during compilations.
875 MutexLocker mu(Compile_lock, THREAD);
876 update_dictionary(d_index, d_hash, p_index, p_hash,
877 k, class_loader, THREAD);
878 }
879
880 if (JvmtiExport::should_post_class_load()) {
881 Thread *thread = THREAD;
882 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
883 JvmtiExport::post_class_load((JavaThread *) thread, k());
884 }
885 }
886 }
887 } // load_instance_class loop
888
889 if (load_instance_added == true) {
890 // clean up placeholder entries for LOAD_INSTANCE success or error
891 // This brackets the SystemDictionary updates for both defining
892 // and initiating loaders
893 MutexLocker mu(SystemDictionary_lock, THREAD);
894 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
895 SystemDictionary_lock->notify_all();
896 }
897 }
898
899 if (HAS_PENDING_EXCEPTION || k.is_null()) {
900 return NULL;
901 }
902
903 post_class_load_event(class_load_start_time, k, loader_data);
904
905 #ifdef ASSERT
906 {
907 ClassLoaderData* loader_data = k->class_loader_data();
908 MutexLocker mu(SystemDictionary_lock, THREAD);
909 Klass* kk = find_class(name, loader_data);
910 assert(kk == k(), "should be present in dictionary");
911 }
912 #endif
913
914 // return if the protection domain in NULL
915 if (protection_domain() == NULL) return k();
916
917 // Check the protection domain has the right access
918 {
919 MutexLocker mu(SystemDictionary_lock, THREAD);
920 // Note that we have an entry, and entries can be deleted only during GC,
921 // so we cannot allow GC to occur while we're holding this entry.
922 // We're using a NoSafepointVerifier to catch any place where we
923 // might potentially do a GC at all.
924 // Dictionary::do_unloading() asserts that classes in SD are only
925 // unloaded at a safepoint. Anonymous classes are not in SD.
926 NoSafepointVerifier nosafepoint;
927 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
928 loader_data,
929 protection_domain)) {
930 return k();
931 }
932 }
933
934 // Verify protection domain. If it fails an exception is thrown
935 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
936
937 return k();
938 }
939
940
941 // This routine does not lock the system dictionary.
942 //
943 // Since readers don't hold a lock, we must make sure that system
944 // dictionary entries are only removed at a safepoint (when only one
945 // thread is running), and are added to in a safe way (all links must
946 // be updated in an MT-safe manner).
947 //
948 // Callers should be aware that an entry could be added just after
949 // _dictionary->bucket(index) is read here, so the caller will not see
950 // the new entry.
951
952 Klass* SystemDictionary::find(Symbol* class_name,
953 Handle class_loader,
954 Handle protection_domain,
955 TRAPS) {
956
957 // The result of this call should be consistent with the result
958 // of the call to resolve_instance_class_or_null().
959 // See evaluation 6790209 and 4474172 for more details.
960 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
961 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
962
963 if (loader_data == NULL) {
964 // If the ClassLoaderData has not been setup,
965 // then the class loader has no entries in the dictionary.
966 return NULL;
967 }
968
969 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
970 int d_index = dictionary()->hash_to_index(d_hash);
971
972 {
973 // Note that we have an entry, and entries can be deleted only during GC,
974 // so we cannot allow GC to occur while we're holding this entry.
975 // We're using a NoSafepointVerifier to catch any place where we
976 // might potentially do a GC at all.
977 // Dictionary::do_unloading() asserts that classes in SD are only
978 // unloaded at a safepoint. Anonymous classes are not in SD.
979 NoSafepointVerifier nosafepoint;
980 return dictionary()->find(d_index, d_hash, class_name, loader_data,
981 protection_domain, THREAD);
982 }
983 }
984
985
986 // Look for a loaded instance or array klass by name. Do not do any loading.
987 // return NULL in case of error.
988 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
989 Handle class_loader,
990 Handle protection_domain,
991 TRAPS) {
992 Klass* k = NULL;
993 assert(class_name != NULL, "class name must be non NULL");
994
995 if (FieldType::is_array(class_name)) {
996 // The name refers to an array. Parse the name.
997 // dimension and object_key in FieldArrayInfo are assigned as a
998 // side-effect of this call
999 FieldArrayInfo fd;
1000 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1001 if (t != T_OBJECT) {
1002 k = Universe::typeArrayKlassObj(t);
1003 } else {
1004 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1005 }
1006 if (k != NULL) {
1007 k = k->array_klass_or_null(fd.dimension());
1008 }
1009 } else {
1010 k = find(class_name, class_loader, protection_domain, THREAD);
1011 }
1012 return k;
1013 }
1014
1015 // Note: this method is much like resolve_from_stream, but
1016 // does not publish the classes via the SystemDictionary.
1017 // Handles unsafe_DefineAnonymousClass and redefineclasses
1018 // RedefinedClasses do not add to the class hierarchy
1019 Klass* SystemDictionary::parse_stream(Symbol* class_name,
1020 Handle class_loader,
1021 Handle protection_domain,
1022 ClassFileStream* st,
1023 const InstanceKlass* host_klass,
1024 GrowableArray<Handle>* cp_patches,
1025 TRAPS) {
1026
1027 Ticks class_load_start_time = Ticks::now();
1028
1029 ClassLoaderData* loader_data;
1030 if (host_klass != NULL) {
1031 // Create a new CLD for anonymous class, that uses the same class loader
1032 // as the host_klass
1033 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1034 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1035 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1036 loader_data->record_dependency(host_klass, CHECK_NULL);
1037 } else {
1038 loader_data = ClassLoaderData::class_loader_data(class_loader());
1039 }
1040
1041 assert(st != NULL, "invariant");
1042 assert(st->need_verify(), "invariant");
1043
1044 // Parse stream and create a klass.
1045 // Note that we do this even though this klass might
1046 // already be present in the SystemDictionary, otherwise we would not
1047 // throw potential ClassFormatErrors.
1048
1049 instanceKlassHandle k = KlassFactory::create_from_stream(st,
1050 class_name,
1051 loader_data,
1052 protection_domain,
1053 host_klass,
1054 cp_patches,
1055 CHECK_NULL);
1056
1057 if (host_klass != NULL && k.not_null()) {
1058 // If it's anonymous, initialize it now, since nobody else will.
1059
1060 {
1061 MutexLocker mu_r(Compile_lock, THREAD);
1062
1063 // Add to class hierarchy, initialize vtables, and do possible
1064 // deoptimizations.
1065 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1066
1067 // But, do not add to system dictionary.
1068
1069 // compiled code dependencies need to be validated anyway
1070 notice_modification();
1071 }
1072
1073 // Rewrite and patch constant pool here.
1074 k->link_class(CHECK_NULL);
1075 if (cp_patches != NULL) {
1076 k->constants()->patch_resolved_references(cp_patches);
1077 }
1078 k->eager_initialize(CHECK_NULL);
1079
1080 // notify jvmti
1081 if (JvmtiExport::should_post_class_load()) {
1082 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1083 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1084 }
1085
1086 post_class_load_event(class_load_start_time, k, loader_data);
1087 }
1088 assert(host_klass != NULL || NULL == cp_patches,
1089 "cp_patches only found with host_klass");
1090
1091 return k();
1092 }
1093
1094 // Add a klass to the system from a stream (called by jni_DefineClass and
1095 // JVM_DefineClass).
1096 // Note: class_name can be NULL. In that case we do not know the name of
1097 // the class until we have parsed the stream.
1098
1099 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1100 Handle class_loader,
1101 Handle protection_domain,
1102 ClassFileStream* st,
1103 TRAPS) {
1104
1105 // Classloaders that support parallelism, e.g. bootstrap classloader,
1106 // or all classloaders with UnsyncloadClass do not acquire lock here
1107 bool DoObjectLock = true;
1108 if (is_parallelCapable(class_loader)) {
1109 DoObjectLock = false;
1110 }
1111
1112 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1113
1114 // Make sure we are synchronized on the class loader before we proceed
1115 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1116 check_loader_lock_contention(lockObject, THREAD);
1117 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1118
1119 assert(st != NULL, "invariant");
1120
1121 // Parse the stream and create a klass.
1122 // Note that we do this even though this klass might
1123 // already be present in the SystemDictionary, otherwise we would not
1124 // throw potential ClassFormatErrors.
1125 //
1126
1127 instanceKlassHandle k;
1128
1129 #if INCLUDE_CDS
1130 k = SystemDictionaryShared::lookup_from_stream(class_name,
1131 class_loader,
1132 protection_domain,
1133 st,
1134 CHECK_NULL);
1135 #endif
1136
1137 if (k.is_null()) {
1138 if (st->buffer() == NULL) {
1139 return NULL;
1140 }
1141 k = KlassFactory::create_from_stream(st,
1142 class_name,
1143 loader_data,
1144 protection_domain,
1145 NULL, // host_klass
1146 NULL, // cp_patches
1147 CHECK_NULL);
1148 }
1149
1150 assert(k.not_null(), "no klass created");
1151 Symbol* h_name = k->name();
1152 assert(class_name == NULL || class_name == h_name, "name mismatch");
1153
1154 // Add class just loaded
1155 // If a class loader supports parallel classloading handle parallel define requests
1156 // find_or_define_instance_class may return a different InstanceKlass
1157 if (is_parallelCapable(class_loader)) {
1158 k = find_or_define_instance_class(h_name, class_loader, k, CHECK_NULL);
1159 } else {
1160 define_instance_class(k, CHECK_NULL);
1161 }
1162
1163 // Make sure we have an entry in the SystemDictionary on success
1164 debug_only( {
1165 MutexLocker mu(SystemDictionary_lock, THREAD);
1166
1167 Klass* check = find_class(h_name, k->class_loader_data());
1168 assert(check == k(), "should be present in the dictionary");
1169 } );
1170
1171 return k();
1172 }
1173
1174 #if INCLUDE_CDS
1175 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1176 int number_of_entries) {
1177 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1178 "bad shared dictionary size.");
1179 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1180 }
1181
1182
1183 // If there is a shared dictionary, then find the entry for the
1184 // given shared system class, if any.
1185
1186 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1187 if (shared_dictionary() != NULL) {
1188 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1189 int d_index = shared_dictionary()->hash_to_index(d_hash);
1190
1191 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1192 } else {
1193 return NULL;
1194 }
1195 }
1196
1197
1198 // Load a class from the shared spaces (found through the shared system
1199 // dictionary). Force the superclass and all interfaces to be loaded.
1200 // Update the class definition to include sibling classes and no
1201 // subclasses (yet). [Classes in the shared space are not part of the
1202 // object hierarchy until loaded.]
1203
1204 instanceKlassHandle SystemDictionary::load_shared_class(
1205 Symbol* class_name, Handle class_loader, TRAPS) {
1206 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1207 // Make sure we only return the boot class for the NULL classloader.
1208 if (ik.not_null() &&
1209 ik->is_shared_boot_class() && class_loader.is_null()) {
1210 Handle protection_domain;
1211 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1212 }
1213 return instanceKlassHandle();
1214 }
1215
1216 // Check if a shared class can be loaded by the specific classloader:
1217 //
1218 // NULL classloader:
1219 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1220 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1221 // be defined in an unnamed module.
1222 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1223 instanceKlassHandle ik,
1224 Handle class_loader, TRAPS) {
1225 ResourceMark rm;
1226 int path_index = ik->shared_classpath_index();
1227 SharedClassPathEntry* ent =
1228 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1229 if (!Universe::is_module_initialized()) {
1230 assert(ent != NULL && ent->is_jrt(),
1231 "Loading non-bootstrap classes before the module system is initialized");
1232 assert(class_loader.is_null(), "sanity");
1233 return true;
1234 }
1235 // Get the pkg_entry from the classloader
1236 TempNewSymbol pkg_name = NULL;
1237 PackageEntry* pkg_entry = NULL;
1238 ModuleEntry* mod_entry = NULL;
1239 const char* pkg_string = NULL;
1240 ClassLoaderData* loader_data = class_loader_data(class_loader);
1241 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1242 if (pkg_name != NULL) {
1243 pkg_string = pkg_name->as_C_string();
1244 if (loader_data != NULL) {
1245 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1246 }
1247 if (pkg_entry != NULL) {
1248 mod_entry = pkg_entry->module();
1249 }
1250 }
1251
1252 if (class_loader.is_null()) {
1253 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1254 // The NULL classloader can load archived class originated from the
1255 // "modules" jimage and the -Xbootclasspath/a. For class from the
1256 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1257 // by the NULL classloader.
1258 if (mod_entry != NULL) {
1259 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1260 // ModuleEntry's location agrees with the archived class' origination.
1261 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1262 return true; // Module class from the "module" jimage
1263 }
1264 }
1265
1266 // If the archived class is not from the "module" jimage, the class can be
1267 // loaded by the NULL classloader if
1268 //
1269 // 1. the class is from the unamed package
1270 // 2. or, the class is not from a module defined in the NULL classloader
1271 // 3. or, the class is from an unamed module
1272 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1273 // the class is from the -Xbootclasspath/a
1274 if (pkg_string == NULL ||
1275 pkg_entry == NULL ||
1276 pkg_entry->in_unnamed_module()) {
1277 assert(mod_entry == NULL ||
1278 mod_entry == loader_data->modules()->unnamed_module(),
1279 "the unnamed module is not defined in the classloader");
1280 return true;
1281 }
1282 }
1283 return false;
1284 } else {
1285 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1286 ik, class_loader, pkg_string, pkg_name,
1287 pkg_entry, mod_entry, CHECK_(false));
1288 return res;
1289 }
1290 }
1291
1292 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1293 Handle class_loader,
1294 Handle protection_domain, TRAPS) {
1295 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1296
1297 if (ik.not_null()) {
1298 Symbol* class_name = ik->name();
1299
1300 bool visible = is_shared_class_visible(
1301 class_name, ik, class_loader, CHECK_(nh));
1302 if (!visible) {
1303 return nh;
1304 }
1305
1306 // Resolve the superclass and interfaces. They must be the same
1307 // as in dump time, because the layout of <ik> depends on
1308 // the specific layout of ik->super() and ik->local_interfaces().
1309 //
1310 // If unexpected superclass or interfaces are found, we cannot
1311 // load <ik> from the shared archive.
1312
1313 if (ik->super() != NULL) {
1314 Symbol* cn = ik->super()->name();
1315 Klass *s = resolve_super_or_fail(class_name, cn,
1316 class_loader, protection_domain, true, CHECK_(nh));
1317 if (s != ik->super()) {
1318 // The dynamically resolved super class is not the same as the one we used during dump time,
1319 // so we cannot use ik.
1320 return nh;
1321 } else {
1322 assert(s->is_shared(), "must be");
1323 }
1324 }
1325
1326 Array<Klass*>* interfaces = ik->local_interfaces();
1327 int num_interfaces = interfaces->length();
1328 for (int index = 0; index < num_interfaces; index++) {
1329 Klass* k = interfaces->at(index);
1330
1331 // Note: can not use InstanceKlass::cast here because
1332 // interfaces' InstanceKlass's C++ vtbls haven't been
1333 // reinitialized yet (they will be once the interface classes
1334 // are loaded)
1335 Symbol* name = k->name();
1336 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1337 if (k != i) {
1338 // The dynamically resolved interface class is not the same as the one we used during dump time,
1339 // so we cannot use ik.
1340 return nh;
1341 } else {
1342 assert(i->is_shared(), "must be");
1343 }
1344 }
1345
1346 instanceKlassHandle new_ik = KlassFactory::check_shared_class_file_load_hook(
1347 ik, class_name, class_loader, protection_domain, CHECK_(nh));
1348 if (new_ik.not_null()) {
1349 // The class is changed by CFLH. Return the new class. The shared class is
1350 // not used.
1351 return new_ik;
1352 }
1353
1354 // Adjust methods to recover missing data. They need addresses for
1355 // interpreter entry points and their default native method address
1356 // must be reset.
1357
1358 // Updating methods must be done under a lock so multiple
1359 // threads don't update these in parallel
1360 //
1361 // Shared classes are all currently loaded by either the bootstrap or
1362 // internal parallel class loaders, so this will never cause a deadlock
1363 // on a custom class loader lock.
1364
1365 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1366 {
1367 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1368 check_loader_lock_contention(lockObject, THREAD);
1369 ObjectLocker ol(lockObject, THREAD, true);
1370 // prohibited package check assumes all classes loaded from archive call
1371 // restore_unshareable_info which calls ik->set_package()
1372 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1373 }
1374
1375 if (log_is_enabled(Info, class, load)) {
1376 ik()->print_loading_log(LogLevel::Info, loader_data, NULL, NULL);
1377 }
1378 // No 'else' here as logging levels are not mutually exclusive
1379
1380 if (log_is_enabled(Debug, class, load)) {
1381 ik()->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL);
1382 }
1383
1384 // For boot loader, ensure that GetSystemPackage knows that a class in this
1385 // package was loaded.
1386 if (class_loader.is_null()) {
1387 int path_index = ik->shared_classpath_index();
1388 ResourceMark rm;
1389 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1390 }
1391
1392 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1393 // Only dump the classes that can be stored into CDS archive
1394 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1395 ResourceMark rm(THREAD);
1396 classlist_file->print_cr("%s", ik->name()->as_C_string());
1397 classlist_file->flush();
1398 }
1399 }
1400
1401 // notify a class loaded from shared object
1402 ClassLoadingService::notify_class_loaded(ik(), true /* shared class */);
1403 }
1404 return ik;
1405 }
1406 #endif // INCLUDE_CDS
1407
1408 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1409 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1410
1411 if (class_loader.is_null()) {
1412 ResourceMark rm;
1413 PackageEntry* pkg_entry = NULL;
1414 bool search_only_bootloader_append = false;
1415 ClassLoaderData *loader_data = class_loader_data(class_loader);
1416
1417 // Find the package in the boot loader's package entry table.
1418 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1419 if (pkg_name != NULL) {
1420 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1421 }
1422
1423 // Prior to attempting to load the class, enforce the boot loader's
1424 // visibility boundaries.
1425 if (!Universe::is_module_initialized()) {
1426 // During bootstrapping, prior to module initialization, any
1427 // class attempting to be loaded must be checked against the
1428 // java.base packages in the boot loader's PackageEntryTable.
1429 // No class outside of java.base is allowed to be loaded during
1430 // this bootstrapping window.
1431 if (!DumpSharedSpaces) {
1432 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1433 // Class is either in the unnamed package or in
1434 // a named package within the unnamed module. Either
1435 // case is outside of java.base, do not attempt to
1436 // load the class post java.base definition. If
1437 // java.base has not been defined, let the class load
1438 // and its package will be checked later by
1439 // ModuleEntryTable::verify_javabase_packages.
1440 if (ModuleEntryTable::javabase_defined()) {
1441 return nh;
1442 }
1443 } else {
1444 // Check that the class' package is defined within java.base.
1445 ModuleEntry* mod_entry = pkg_entry->module();
1446 Symbol* mod_entry_name = mod_entry->name();
1447 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1448 return nh;
1449 }
1450 }
1451 }
1452 } else {
1453 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1454 // After the module system has been initialized, check if the class'
1455 // package is in a module defined to the boot loader.
1456 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1457 // Class is either in the unnamed package, in a named package
1458 // within a module not defined to the boot loader or in a
1459 // a named package within the unnamed module. In all cases,
1460 // limit visibility to search for the class only in the boot
1461 // loader's append path.
1462 search_only_bootloader_append = true;
1463 }
1464 }
1465
1466 // Prior to bootstrapping's module initialization, never load a class outside
1467 // of the boot loader's module path
1468 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1469 !search_only_bootloader_append,
1470 "Attempt to load a class outside of boot loader's module path");
1471
1472 // Search the shared system dictionary for classes preloaded into the
1473 // shared spaces.
1474 instanceKlassHandle k;
1475 {
1476 #if INCLUDE_CDS
1477 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1478 k = load_shared_class(class_name, class_loader, THREAD);
1479 #endif
1480 }
1481
1482 if (k.is_null()) {
1483 // Use VM class loader
1484 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1485 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_(nh));
1486 }
1487
1488 // find_or_define_instance_class may return a different InstanceKlass
1489 if (!k.is_null()) {
1490 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1491 }
1492 return k;
1493 } else {
1494 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1495 ResourceMark rm(THREAD);
1496
1497 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1498 JavaThread* jt = (JavaThread*) THREAD;
1499
1500 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1501 ClassLoader::perf_app_classload_selftime(),
1502 ClassLoader::perf_app_classload_count(),
1503 jt->get_thread_stat()->perf_recursion_counts_addr(),
1504 jt->get_thread_stat()->perf_timers_addr(),
1505 PerfClassTraceTime::CLASS_LOAD);
1506
1507 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1508 // Translate to external class name format, i.e., convert '/' chars to '.'
1509 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1510
1511 JavaValue result(T_OBJECT);
1512
1513 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1514
1515 // Call public unsynchronized loadClass(String) directly for all class loaders
1516 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1517 // acquire a class-name based lock rather than the class loader object lock.
1518 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1519 // so the call to loadClassInternal() was not required.
1520 //
1521 // UnsyncloadClass flag means both call loadClass(String) and do
1522 // not acquire the class loader lock even for class loaders that are
1523 // not parallelCapable. This was a risky transitional
1524 // flag for diagnostic purposes only. It is risky to call
1525 // custom class loaders without synchronization.
1526 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1527 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1528 // Do NOT assume this will be supported in future releases.
1529 //
1530 // Added MustCallLoadClassInternal in case we discover in the field
1531 // a customer that counts on this call
1532 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1533 JavaCalls::call_special(&result,
1534 class_loader,
1535 spec_klass,
1536 vmSymbols::loadClassInternal_name(),
1537 vmSymbols::string_class_signature(),
1538 string,
1539 CHECK_(nh));
1540 } else {
1541 JavaCalls::call_virtual(&result,
1542 class_loader,
1543 spec_klass,
1544 vmSymbols::loadClass_name(),
1545 vmSymbols::string_class_signature(),
1546 string,
1547 CHECK_(nh));
1548 }
1549
1550 assert(result.get_type() == T_OBJECT, "just checking");
1551 oop obj = (oop) result.get_jobject();
1552
1553 // Primitive classes return null since forName() can not be
1554 // used to obtain any of the Class objects representing primitives or void
1555 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1556 instanceKlassHandle k =
1557 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1558 // For user defined Java class loaders, check that the name returned is
1559 // the same as that requested. This check is done for the bootstrap
1560 // loader when parsing the class file.
1561 if (class_name == k->name()) {
1562 return k;
1563 }
1564 }
1565 // Class is not found or has the wrong name, return NULL
1566 return nh;
1567 }
1568 }
1569
1570 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1571
1572 ClassLoaderData* loader_data = k->class_loader_data();
1573 Handle class_loader_h(THREAD, loader_data->class_loader());
1574
1575 // for bootstrap and other parallel classloaders don't acquire lock,
1576 // use placeholder token
1577 // If a parallelCapable class loader calls define_instance_class instead of
1578 // find_or_define_instance_class to get here, we have a timing
1579 // hole with systemDictionary updates and check_constraints
1580 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1581 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1582 compute_loader_lock_object(class_loader_h, THREAD)),
1583 "define called without lock");
1584 }
1585
1586 // Check class-loading constraints. Throw exception if violation is detected.
1587 // Grabs and releases SystemDictionary_lock
1588 // The check_constraints/find_class call and update_dictionary sequence
1589 // must be "atomic" for a specific class/classloader pair so we never
1590 // define two different instanceKlasses for that class/classloader pair.
1591 // Existing classloaders will call define_instance_class with the
1592 // classloader lock held
1593 // Parallel classloaders will call find_or_define_instance_class
1594 // which will require a token to perform the define class
1595 Symbol* name_h = k->name();
1596 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1597 int d_index = dictionary()->hash_to_index(d_hash);
1598 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1599
1600 // Register class just loaded with class loader (placed in Vector)
1601 // Note we do this before updating the dictionary, as this can
1602 // fail with an OutOfMemoryError (if it does, we will *not* put this
1603 // class in the dictionary and will not update the class hierarchy).
1604 // JVMTI FollowReferences needs to find the classes this way.
1605 if (k->class_loader() != NULL) {
1606 methodHandle m(THREAD, Universe::loader_addClass_method());
1607 JavaValue result(T_VOID);
1608 JavaCallArguments args(class_loader_h);
1609 args.push_oop(Handle(THREAD, k->java_mirror()));
1610 JavaCalls::call(&result, m, &args, CHECK);
1611 }
1612
1613 // Add the new class. We need recompile lock during update of CHA.
1614 {
1615 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1616 int p_index = placeholders()->hash_to_index(p_hash);
1617
1618 MutexLocker mu_r(Compile_lock, THREAD);
1619
1620 // Add to class hierarchy, initialize vtables, and do possible
1621 // deoptimizations.
1622 add_to_hierarchy(k, CHECK); // No exception, but can block
1623
1624 // Add to systemDictionary - so other classes can see it.
1625 // Grabs and releases SystemDictionary_lock
1626 update_dictionary(d_index, d_hash, p_index, p_hash,
1627 k, class_loader_h, THREAD);
1628 }
1629 k->eager_initialize(THREAD);
1630
1631 // notify jvmti
1632 if (JvmtiExport::should_post_class_load()) {
1633 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1634 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1635
1636 }
1637 class_define_event(k, loader_data);
1638 }
1639
1640 // Support parallel classloading
1641 // All parallel class loaders, including bootstrap classloader
1642 // lock a placeholder entry for this class/class_loader pair
1643 // to allow parallel defines of different classes for this class loader
1644 // With AllowParallelDefine flag==true, in case they do not synchronize around
1645 // FindLoadedClass/DefineClass, calls, we check for parallel
1646 // loading for them, wait if a defineClass is in progress
1647 // and return the initial requestor's results
1648 // This flag does not apply to the bootstrap classloader.
1649 // With AllowParallelDefine flag==false, call through to define_instance_class
1650 // which will throw LinkageError: duplicate class definition.
1651 // False is the requested default.
1652 // For better performance, the class loaders should synchronize
1653 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1654 // potentially waste time reading and parsing the bytestream.
1655 // Note: VM callers should ensure consistency of k/class_name,class_loader
1656 // Be careful when modifying this code: once you have run
1657 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1658 // you need to find_and_remove it before returning.
1659 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1660 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1661
1662 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1663 Symbol* name_h = k->name(); // passed in class_name may be null
1664 ClassLoaderData* loader_data = class_loader_data(class_loader);
1665
1666 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1667 int d_index = dictionary()->hash_to_index(d_hash);
1668
1669 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1670 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1671 int p_index = placeholders()->hash_to_index(p_hash);
1672 PlaceholderEntry* probe;
1673
1674 {
1675 MutexLocker mu(SystemDictionary_lock, THREAD);
1676 // First check if class already defined
1677 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1678 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1679 if (check != NULL) {
1680 return(instanceKlassHandle(THREAD, check));
1681 }
1682 }
1683
1684 // Acquire define token for this class/classloader
1685 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1686 // Wait if another thread defining in parallel
1687 // All threads wait - even those that will throw duplicate class: otherwise
1688 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1689 // if other thread has not finished updating dictionary
1690 while (probe->definer() != NULL) {
1691 SystemDictionary_lock->wait();
1692 }
1693 // Only special cases allow parallel defines and can use other thread's results
1694 // Other cases fall through, and may run into duplicate defines
1695 // caught by finding an entry in the SystemDictionary
1696 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1697 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1698 SystemDictionary_lock->notify_all();
1699 #ifdef ASSERT
1700 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1701 assert(check != NULL, "definer missed recording success");
1702 #endif
1703 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1704 } else {
1705 // This thread will define the class (even if earlier thread tried and had an error)
1706 probe->set_definer(THREAD);
1707 }
1708 }
1709
1710 define_instance_class(k, THREAD);
1711
1712 Handle linkage_exception = Handle(); // null handle
1713
1714 // definer must notify any waiting threads
1715 {
1716 MutexLocker mu(SystemDictionary_lock, THREAD);
1717 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1718 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1719 if (probe != NULL) {
1720 if (HAS_PENDING_EXCEPTION) {
1721 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1722 CLEAR_PENDING_EXCEPTION;
1723 } else {
1724 probe->set_instance_klass(k());
1725 }
1726 probe->set_definer(NULL);
1727 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1728 SystemDictionary_lock->notify_all();
1729 }
1730 }
1731
1732 // Can't throw exception while holding lock due to rank ordering
1733 if (linkage_exception() != NULL) {
1734 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1735 }
1736
1737 return k;
1738 }
1739 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1740 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1741 if (class_loader.is_null()) {
1742 return Handle(THREAD, _system_loader_lock_obj);
1743 } else {
1744 return class_loader;
1745 }
1746 }
1747
1748 // This method is added to check how often we have to wait to grab loader
1749 // lock. The results are being recorded in the performance counters defined in
1750 // ClassLoader::_sync_systemLoaderLockContentionRate and
1751 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1752 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1753 if (!UsePerfData) {
1754 return;
1755 }
1756
1757 assert(!loader_lock.is_null(), "NULL lock object");
1758
1759 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1760 == ObjectSynchronizer::owner_other) {
1761 // contention will likely happen, so increment the corresponding
1762 // contention counter.
1763 if (loader_lock() == _system_loader_lock_obj) {
1764 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1765 } else {
1766 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1767 }
1768 }
1769 }
1770
1771 // ----------------------------------------------------------------------------
1772 // Lookup
1773
1774 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1775 Symbol* class_name,
1776 ClassLoaderData* loader_data) {
1777 assert_locked_or_safepoint(SystemDictionary_lock);
1778 assert (index == dictionary()->index_for(class_name, loader_data),
1779 "incorrect index?");
1780
1781 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1782 return k;
1783 }
1784
1785
1786 // Basic find on classes in the midst of being loaded
1787 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1788 ClassLoaderData* loader_data) {
1789 assert_locked_or_safepoint(SystemDictionary_lock);
1790 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1791 int p_index = placeholders()->hash_to_index(p_hash);
1792 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1793 }
1794
1795
1796 // Used for assertions and verification only
1797 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1798 #ifndef ASSERT
1799 guarantee(VerifyBeforeGC ||
1800 VerifyDuringGC ||
1801 VerifyBeforeExit ||
1802 VerifyDuringStartup ||
1803 VerifyAfterGC, "too expensive");
1804 #endif
1805 assert_locked_or_safepoint(SystemDictionary_lock);
1806
1807 // First look in the loaded class array
1808 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1809 int d_index = dictionary()->hash_to_index(d_hash);
1810 return find_class(d_index, d_hash, class_name, loader_data);
1811 }
1812
1813
1814 // Get the next class in the dictionary.
1815 Klass* SystemDictionary::try_get_next_class() {
1816 return dictionary()->try_get_next_class();
1817 }
1818
1819
1820 // ----------------------------------------------------------------------------
1821 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1822 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1823 // before a new class is used.
1824
1825 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1826 assert(k.not_null(), "just checking");
1827 assert_locked_or_safepoint(Compile_lock);
1828
1829 // Link into hierachy. Make sure the vtables are initialized before linking into
1830 k->append_to_sibling_list(); // add to superklass/sibling list
1831 k->process_interfaces(THREAD); // handle all "implements" declarations
1832 k->set_init_state(InstanceKlass::loaded);
1833 // Now flush all code that depended on old class hierarchy.
1834 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1835 // Also, first reinitialize vtable because it may have gotten out of synch
1836 // while the new class wasn't connected to the class hierarchy.
1837 CodeCache::flush_dependents_on(k);
1838 }
1839
1840 // ----------------------------------------------------------------------------
1841 // GC support
1842
1843 // Following roots during mark-sweep is separated in two phases.
1844 //
1845 // The first phase follows preloaded classes and all other system
1846 // classes, since these will never get unloaded anyway.
1847 //
1848 // The second phase removes (unloads) unreachable classes from the
1849 // system dictionary and follows the remaining classes' contents.
1850
1851 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1852 roots_oops_do(blk, NULL);
1853 }
1854
1855 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1856 // Follow all system classes and temporary placeholders in dictionary
1857 dictionary()->always_strong_classes_do(closure);
1858
1859 // Placeholders. These represent classes we're actively loading.
1860 placeholders()->classes_do(closure);
1861 }
1862
1863 // Calculate a "good" systemdictionary size based
1864 // on predicted or current loaded classes count
1865 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1866 int newsize = _old_default_sdsize;
1867 if ((classcount > 0) && !DumpSharedSpaces) {
1868 int desiredsize = classcount/_average_depth_goal;
1869 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1870 newsize = _primelist[++_sdgeneration]) {
1871 if (desiredsize <= newsize) {
1872 break;
1873 }
1874 }
1875 }
1876 return newsize;
1877 }
1878
1879 #ifdef ASSERT
1880 class VerifySDReachableAndLiveClosure : public OopClosure {
1881 private:
1882 BoolObjectClosure* _is_alive;
1883
1884 template <class T> void do_oop_work(T* p) {
1885 oop obj = oopDesc::load_decode_heap_oop(p);
1886 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1887 }
1888
1889 public:
1890 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1891
1892 virtual void do_oop(oop* p) { do_oop_work(p); }
1893 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1894 };
1895 #endif
1896
1897 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1898 // Note: anonymous classes are not in the SD.
1899 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1900 bool clean_previous_versions) {
1901 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1902 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1903 clean_previous_versions);
1904 if (unloading_occurred) {
1905 dictionary()->do_unloading();
1906 constraints()->purge_loader_constraints();
1907 resolution_errors()->purge_resolution_errors();
1908 }
1909 // Oops referenced by the system dictionary may get unreachable independently
1910 // of the class loader (eg. cached protection domain oops). So we need to
1911 // explicitly unlink them here instead of in Dictionary::do_unloading.
1912 dictionary()->unlink(is_alive);
1913 #ifdef ASSERT
1914 VerifySDReachableAndLiveClosure cl(is_alive);
1915 dictionary()->oops_do(&cl);
1916 #endif
1917 return unloading_occurred;
1918 }
1919
1920 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1921 strong->do_oop(&_java_system_loader);
1922 strong->do_oop(&_system_loader_lock_obj);
1923 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1924
1925 // Adjust dictionary
1926 dictionary()->roots_oops_do(strong, weak);
1927
1928 // Visit extra methods
1929 invoke_method_table()->oops_do(strong);
1930 }
1931
1932 void SystemDictionary::oops_do(OopClosure* f) {
1933 f->do_oop(&_java_system_loader);
1934 f->do_oop(&_system_loader_lock_obj);
1935 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1936
1937 // Adjust dictionary
1938 dictionary()->oops_do(f);
1939
1940 // Visit extra methods
1941 invoke_method_table()->oops_do(f);
1942 }
1943
1944 // Extended Class redefinition support.
1945 // If one of these classes is replaced, we need to replace it in these places.
1946 // KlassClosure::do_klass should take the address of a class but we can
1947 // change that later.
1948 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1949 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1950 f->do_klass(_well_known_klasses[k]);
1951 }
1952
1953 {
1954 for (int i = 0; i < T_VOID+1; i++) {
1955 if (_box_klasses[i] != NULL) {
1956 assert(i >= T_BOOLEAN, "checking");
1957 f->do_klass(_box_klasses[i]);
1958 }
1959 }
1960 }
1961
1962 FilteredFieldsMap::classes_do(f);
1963 }
1964
1965 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1966 f->do_klass(_abstract_ownable_synchronizer_klass);
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::placeholders_do(void f(Symbol*)) {
1989 placeholders()->entries_do(f);
1990 }
1991
1992 void SystemDictionary::methods_do(void f(Method*)) {
1993 dictionary()->methods_do(f);
1994 invoke_method_table()->methods_do(f);
1995 }
1996
1997 void SystemDictionary::remove_classes_in_error_state() {
1998 dictionary()->remove_classes_in_error_state();
1999 }
2000
2001 // ----------------------------------------------------------------------------
2002 // Lazily load klasses
2003
2004 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2005 // if multiple threads calling this function, only one thread will load
2006 // the class. The other threads will find the loaded version once the
2007 // class is loaded.
2008 Klass* aos = _abstract_ownable_synchronizer_klass;
2009 if (aos == NULL) {
2010 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2011 // Force a fence to prevent any read before the write completes
2012 OrderAccess::fence();
2013 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2014 }
2015 }
2016
2017 // ----------------------------------------------------------------------------
2018 // Initialization
2019
2020 void SystemDictionary::initialize(TRAPS) {
2021 // Allocate arrays
2022 assert(dictionary() == NULL,
2023 "SystemDictionary should only be initialized once");
2024 _sdgeneration = 0;
2025 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2026 _placeholders = new PlaceholderTable(_nof_buckets);
2027 _number_of_modifications = 0;
2028 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2029 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2030 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2031
2032 // Allocate private object used as system class loader lock
2033 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2034 // Initialize basic classes
2035 initialize_preloaded_classes(CHECK);
2036 }
2037
2038 // Compact table of directions on the initialization of klasses:
2039 static const short wk_init_info[] = {
2040 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2041 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2042 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2043 | (int)SystemDictionary::option ),
2044 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2045 #undef WK_KLASS_INIT_INFO
2046 0
2047 };
2048
2049 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2050 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2051 int info = wk_init_info[id - FIRST_WKID];
2052 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2053 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2054 InstanceKlass** klassp = &_well_known_klasses[id];
2055
2056 bool must_load;
2057 #if INCLUDE_JVMCI
2058 if (EnableJVMCI) {
2059 // If JVMCI is enabled we require its classes to be found.
2060 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2061 } else
2062 #endif
2063 {
2064 must_load = (init_opt < SystemDictionary::Opt);
2065 }
2066
2067 if ((*klassp) == NULL) {
2068 Klass* k;
2069 if (must_load) {
2070 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2071 } else {
2072 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2073 }
2074 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2075 }
2076 return ((*klassp) != NULL);
2077 }
2078
2079 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2080 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2081 for (int id = (int)start_id; id < (int)limit_id; id++) {
2082 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2083 int info = wk_init_info[id - FIRST_WKID];
2084 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2085 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2086
2087 initialize_wk_klass((WKID)id, opt, CHECK);
2088 }
2089
2090 // move the starting value forward to the limit:
2091 start_id = limit_id;
2092 }
2093
2094 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2095 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2096
2097 // Create the ModuleEntry for java.base. This call needs to be done here,
2098 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2099 ClassLoader::classLoader_init2(CHECK);
2100
2101 // Preload commonly used klasses
2102 WKID scan = FIRST_WKID;
2103 // first do Object, then String, Class
2104 if (UseSharedSpaces) {
2105 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2106 // Initialize the constant pool for the Object_class
2107 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
2108 ik->constants()->restore_unshareable_info(CHECK);
2109 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2110 } else {
2111 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2112 }
2113
2114 // Calculate offsets for String and Class classes since they are loaded and
2115 // can be used after this point.
2116 java_lang_String::compute_offsets();
2117 java_lang_Class::compute_offsets();
2118
2119 // Fixup mirrors for classes loaded before java.lang.Class.
2120 // These calls iterate over the objects currently in the perm gen
2121 // so calling them at this point is matters (not before when there
2122 // are fewer objects and not later after there are more objects
2123 // in the perm gen.
2124 Universe::initialize_basic_type_mirrors(CHECK);
2125 Universe::fixup_mirrors(CHECK);
2126
2127 // do a bunch more:
2128 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2129
2130 // Preload ref klasses and set reference types
2131 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2132 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2133
2134 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2135 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2136 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2137 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2138 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2139
2140 // JSR 292 classes
2141 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2142 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2143 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2144 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2145 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2146
2147 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2148 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2149 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2150 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2151 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2152 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2153 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2154 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2155 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2156 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2157
2158 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2159 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2160 _has_loadClassInternal = (method != NULL);
2161 }
2162 { // Compute whether we should use checkPackageAccess or NOT
2163 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2164 _has_checkPackageAccess = (method != NULL);
2165 }
2166 }
2167
2168 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2169 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2170 BasicType SystemDictionary::box_klass_type(Klass* k) {
2171 assert(k != NULL, "");
2172 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2173 if (_box_klasses[i] == k)
2174 return (BasicType)i;
2175 }
2176 return T_OBJECT;
2177 }
2178
2179 // Constraints on class loaders. The details of the algorithm can be
2180 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2181 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2182 // that the system dictionary needs to maintain a set of contraints that
2183 // must be satisfied by all classes in the dictionary.
2184 // if defining is true, then LinkageError if already in systemDictionary
2185 // if initiating loader, then ok if InstanceKlass matches existing entry
2186
2187 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2188 instanceKlassHandle k,
2189 Handle class_loader, bool defining,
2190 TRAPS) {
2191 const char *linkage_error1 = NULL;
2192 const char *linkage_error2 = NULL;
2193 {
2194 Symbol* name = k->name();
2195 ClassLoaderData *loader_data = class_loader_data(class_loader);
2196
2197 MutexLocker mu(SystemDictionary_lock, THREAD);
2198
2199 Klass* check = find_class(d_index, d_hash, name, loader_data);
2200 if (check != (Klass*)NULL) {
2201 // if different InstanceKlass - duplicate class definition,
2202 // else - ok, class loaded by a different thread in parallel,
2203 // we should only have found it if it was done loading and ok to use
2204 // system dictionary only holds instance classes, placeholders
2205 // also holds array classes
2206
2207 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2208 if ((defining == true) || (k() != check)) {
2209 linkage_error1 = "loader (instance of ";
2210 linkage_error2 = "): attempted duplicate class definition for name: \"";
2211 } else {
2212 return;
2213 }
2214 }
2215
2216 #ifdef ASSERT
2217 Symbol* ph_check = find_placeholder(name, loader_data);
2218 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2219 #endif
2220
2221 if (linkage_error1 == NULL) {
2222 if (constraints()->check_or_update(k, class_loader, name) == false) {
2223 linkage_error1 = "loader constraint violation: loader (instance of ";
2224 linkage_error2 = ") previously initiated loading for a different type with name \"";
2225 }
2226 }
2227 }
2228
2229 // Throw error now if needed (cannot throw while holding
2230 // SystemDictionary_lock because of rank ordering)
2231
2232 if (linkage_error1) {
2233 ResourceMark rm(THREAD);
2234 const char* class_loader_name = loader_name(class_loader());
2235 char* type_name = k->name()->as_C_string();
2236 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2237 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2238 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2239 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2240 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2241 }
2242 }
2243
2244
2245 // Update system dictionary - done after check_constraint and add_to_hierachy
2246 // have been called.
2247 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2248 int p_index, unsigned int p_hash,
2249 instanceKlassHandle k,
2250 Handle class_loader,
2251 TRAPS) {
2252 // Compile_lock prevents systemDictionary updates during compilations
2253 assert_locked_or_safepoint(Compile_lock);
2254 Symbol* name = k->name();
2255 ClassLoaderData *loader_data = class_loader_data(class_loader);
2256
2257 {
2258 MutexLocker mu1(SystemDictionary_lock, THREAD);
2259
2260 // See whether biased locking is enabled and if so set it for this
2261 // klass.
2262 // Note that this must be done past the last potential blocking
2263 // point / safepoint. We enable biased locking lazily using a
2264 // VM_Operation to iterate the SystemDictionary and installing the
2265 // biasable mark word into each InstanceKlass's prototype header.
2266 // To avoid race conditions where we accidentally miss enabling the
2267 // optimization for one class in the process of being added to the
2268 // dictionary, we must not safepoint after the test of
2269 // BiasedLocking::enabled().
2270 if (UseBiasedLocking && BiasedLocking::enabled()) {
2271 // Set biased locking bit for all loaded classes; it will be
2272 // cleared if revocation occurs too often for this type
2273 // NOTE that we must only do this when the class is initally
2274 // defined, not each time it is referenced from a new class loader
2275 if (k->class_loader() == class_loader()) {
2276 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2277 }
2278 }
2279
2280 // Make a new system dictionary entry.
2281 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2282 if (sd_check == NULL) {
2283 dictionary()->add_klass(name, loader_data, k);
2284 notice_modification();
2285 }
2286 #ifdef ASSERT
2287 sd_check = find_class(d_index, d_hash, name, loader_data);
2288 assert (sd_check != NULL, "should have entry in system dictionary");
2289 // Note: there may be a placeholder entry: for circularity testing
2290 // or for parallel defines
2291 #endif
2292 SystemDictionary_lock->notify_all();
2293 }
2294 }
2295
2296
2297 // Try to find a class name using the loader constraints. The
2298 // loader constraints might know about a class that isn't fully loaded
2299 // yet and these will be ignored.
2300 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2301 Symbol* class_name, Handle class_loader, TRAPS) {
2302
2303 // First see if it has been loaded directly.
2304 // Force the protection domain to be null. (This removes protection checks.)
2305 Handle no_protection_domain;
2306 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2307 no_protection_domain, CHECK_NULL);
2308 if (klass != NULL)
2309 return klass;
2310
2311 // Now look to see if it has been loaded elsewhere, and is subject to
2312 // a loader constraint that would require this loader to return the
2313 // klass that is already loaded.
2314 if (FieldType::is_array(class_name)) {
2315 // For array classes, their Klass*s are not kept in the
2316 // constraint table. The element Klass*s are.
2317 FieldArrayInfo fd;
2318 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2319 if (t != T_OBJECT) {
2320 klass = Universe::typeArrayKlassObj(t);
2321 } else {
2322 MutexLocker mu(SystemDictionary_lock, THREAD);
2323 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2324 }
2325 // If element class already loaded, allocate array klass
2326 if (klass != NULL) {
2327 klass = klass->array_klass_or_null(fd.dimension());
2328 }
2329 } else {
2330 MutexLocker mu(SystemDictionary_lock, THREAD);
2331 // Non-array classes are easy: simply check the constraint table.
2332 klass = constraints()->find_constrained_klass(class_name, class_loader);
2333 }
2334
2335 return klass;
2336 }
2337
2338
2339 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2340 Handle class_loader1,
2341 Handle class_loader2,
2342 Thread* THREAD) {
2343 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2344 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2345
2346 Symbol* constraint_name = NULL;
2347 if (!FieldType::is_array(class_name)) {
2348 constraint_name = class_name;
2349 } else {
2350 // For array classes, their Klass*s are not kept in the
2351 // constraint table. The element classes are.
2352 FieldArrayInfo fd;
2353 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2354 // primitive types always pass
2355 if (t != T_OBJECT) {
2356 return true;
2357 } else {
2358 constraint_name = fd.object_key();
2359 }
2360 }
2361 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2362 int d_index1 = dictionary()->hash_to_index(d_hash1);
2363
2364 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2365 int d_index2 = dictionary()->hash_to_index(d_hash2);
2366 {
2367 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2368
2369 // Better never do a GC while we're holding these oops
2370 NoSafepointVerifier nosafepoint;
2371
2372 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2373 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2374 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2375 klass2, class_loader2);
2376 }
2377 }
2378
2379 // Add entry to resolution error table to record the error when the first
2380 // attempt to resolve a reference to a class has failed.
2381 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2382 Symbol* error, Symbol* message) {
2383 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2384 int index = resolution_errors()->hash_to_index(hash);
2385 {
2386 MutexLocker ml(SystemDictionary_lock, Thread::current());
2387 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2388 }
2389 }
2390
2391 // Delete a resolution error for RedefineClasses for a constant pool is going away
2392 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2393 resolution_errors()->delete_entry(pool);
2394 }
2395
2396 // Lookup resolution error table. Returns error if found, otherwise NULL.
2397 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2398 Symbol** message) {
2399 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2400 int index = resolution_errors()->hash_to_index(hash);
2401 {
2402 MutexLocker ml(SystemDictionary_lock, Thread::current());
2403 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2404 if (entry != NULL) {
2405 *message = entry->message();
2406 return entry->error();
2407 } else {
2408 return NULL;
2409 }
2410 }
2411 }
2412
2413
2414 // Signature constraints ensure that callers and callees agree about
2415 // the meaning of type names in their signatures. This routine is the
2416 // intake for constraints. It collects them from several places:
2417 //
2418 // * LinkResolver::resolve_method (if check_access is true) requires
2419 // that the resolving class (the caller) and the defining class of
2420 // the resolved method (the callee) agree on each type in the
2421 // method's signature.
2422 //
2423 // * LinkResolver::resolve_interface_method performs exactly the same
2424 // checks.
2425 //
2426 // * LinkResolver::resolve_field requires that the constant pool
2427 // attempting to link to a field agree with the field's defining
2428 // class about the type of the field signature.
2429 //
2430 // * klassVtable::initialize_vtable requires that, when a class
2431 // overrides a vtable entry allocated by a superclass, that the
2432 // overriding method (i.e., the callee) agree with the superclass
2433 // on each type in the method's signature.
2434 //
2435 // * klassItable::initialize_itable requires that, when a class fills
2436 // in its itables, for each non-abstract method installed in an
2437 // itable, the method (i.e., the callee) agree with the interface
2438 // on each type in the method's signature.
2439 //
2440 // All those methods have a boolean (check_access, checkconstraints)
2441 // which turns off the checks. This is used from specialized contexts
2442 // such as bootstrapping, dumping, and debugging.
2443 //
2444 // No direct constraint is placed between the class and its
2445 // supertypes. Constraints are only placed along linked relations
2446 // between callers and callees. When a method overrides or implements
2447 // an abstract method in a supertype (superclass or interface), the
2448 // constraints are placed as if the supertype were the caller to the
2449 // overriding method. (This works well, since callers to the
2450 // supertype have already established agreement between themselves and
2451 // the supertype.) As a result of all this, a class can disagree with
2452 // its supertype about the meaning of a type name, as long as that
2453 // class neither calls a relevant method of the supertype, nor is
2454 // called (perhaps via an override) from the supertype.
2455 //
2456 //
2457 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2458 //
2459 // Make sure all class components (including arrays) in the given
2460 // signature will be resolved to the same class in both loaders.
2461 // Returns the name of the type that failed a loader constraint check, or
2462 // NULL if no constraint failed. No exception except OOME is thrown.
2463 // Arrays are not added to the loader constraint table, their elements are.
2464 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2465 Handle loader1, Handle loader2,
2466 bool is_method, TRAPS) {
2467 // Nothing to do if loaders are the same.
2468 if (loader1() == loader2()) {
2469 return NULL;
2470 }
2471
2472 SignatureStream sig_strm(signature, is_method);
2473 while (!sig_strm.is_done()) {
2474 if (sig_strm.is_object()) {
2475 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2476 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2477 return sig;
2478 }
2479 }
2480 sig_strm.next();
2481 }
2482 return NULL;
2483 }
2484
2485
2486 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2487 Symbol* signature,
2488 TRAPS) {
2489 methodHandle empty;
2490 assert(MethodHandles::is_signature_polymorphic(iid) &&
2491 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2492 iid != vmIntrinsics::_invokeGeneric,
2493 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2494
2495 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2496 int index = invoke_method_table()->hash_to_index(hash);
2497 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2498 methodHandle m;
2499 if (spe == NULL || spe->method() == NULL) {
2500 spe = NULL;
2501 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2502 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2503 if (!Arguments::is_interpreter_only()) {
2504 // Generate a compiled form of the MH intrinsic.
2505 AdapterHandlerLibrary::create_native_wrapper(m);
2506 // Check if have the compiled code.
2507 if (!m->has_compiled_code()) {
2508 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2509 "Out of space in CodeCache for method handle intrinsic", empty);
2510 }
2511 }
2512 // Now grab the lock. We might have to throw away the new method,
2513 // if a racing thread has managed to install one at the same time.
2514 {
2515 MutexLocker ml(SystemDictionary_lock, THREAD);
2516 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2517 if (spe == NULL)
2518 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2519 if (spe->method() == NULL)
2520 spe->set_method(m());
2521 }
2522 }
2523
2524 assert(spe != NULL && spe->method() != NULL, "");
2525 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2526 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2527 "MH intrinsic invariant");
2528 return spe->method();
2529 }
2530
2531 // Helper for unpacking the return value from linkMethod and linkCallSite.
2532 static methodHandle unpack_method_and_appendix(Handle mname,
2533 KlassHandle accessing_klass,
2534 objArrayHandle appendix_box,
2535 Handle* appendix_result,
2536 TRAPS) {
2537 methodHandle empty;
2538 if (mname.not_null()) {
2539 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2540 if (vmtarget != NULL && vmtarget->is_method()) {
2541 Method* m = (Method*)vmtarget;
2542 oop appendix = appendix_box->obj_at(0);
2543 if (TraceMethodHandles) {
2544 #ifndef PRODUCT
2545 ttyLocker ttyl;
2546 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2547 m->print();
2548 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2549 tty->cr();
2550 #endif //PRODUCT
2551 }
2552 (*appendix_result) = Handle(THREAD, appendix);
2553 // the target is stored in the cpCache and if a reference to this
2554 // MethodName is dropped we need a way to make sure the
2555 // class_loader containing this method is kept alive.
2556 // FIXME: the appendix might also preserve this dependency.
2557 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2558 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2559 return methodHandle(THREAD, m);
2560 }
2561 }
2562 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2563 return empty;
2564 }
2565
2566 methodHandle SystemDictionary::find_method_handle_invoker(KlassHandle klass,
2567 Symbol* name,
2568 Symbol* signature,
2569 KlassHandle accessing_klass,
2570 Handle *appendix_result,
2571 Handle *method_type_result,
2572 TRAPS) {
2573 methodHandle empty;
2574 assert(THREAD->can_call_java() ,"");
2575 Handle method_type =
2576 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2577
2578 int ref_kind = JVM_REF_invokeVirtual;
2579 Handle name_str = StringTable::intern(name, CHECK_(empty));
2580 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2581 assert(appendix_box->obj_at(0) == NULL, "");
2582
2583 // This should not happen. JDK code should take care of that.
2584 if (accessing_klass.is_null() || method_type.is_null()) {
2585 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2586 }
2587
2588 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2589 JavaCallArguments args;
2590 args.push_oop(accessing_klass()->java_mirror());
2591 args.push_int(ref_kind);
2592 args.push_oop(klass()->java_mirror());
2593 args.push_oop(name_str());
2594 args.push_oop(method_type());
2595 args.push_oop(appendix_box());
2596 JavaValue result(T_OBJECT);
2597 JavaCalls::call_static(&result,
2598 SystemDictionary::MethodHandleNatives_klass(),
2599 vmSymbols::linkMethod_name(),
2600 vmSymbols::linkMethod_signature(),
2601 &args, CHECK_(empty));
2602 Handle mname(THREAD, (oop) result.get_jobject());
2603 (*method_type_result) = method_type;
2604 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2605 }
2606
2607 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2608 // We must ensure that all class loaders everywhere will reach this class, for any client.
2609 // This is a safe bet for public classes in java.lang, such as Object and String.
2610 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2611 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2612 static bool is_always_visible_class(oop mirror) {
2613 Klass* klass = java_lang_Class::as_Klass(mirror);
2614 if (klass->is_objArray_klass()) {
2615 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2616 }
2617 if (klass->is_typeArray_klass()) {
2618 return true; // primitive array
2619 }
2620 assert(klass->is_instance_klass(), "%s", klass->external_name());
2621 return klass->is_public() &&
2622 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2623 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2624 }
2625
2626 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2627 // signature, as interpreted relative to the given class loader.
2628 // Because of class loader constraints, all method handle usage must be
2629 // consistent with this loader.
2630 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2631 KlassHandle accessing_klass,
2632 TRAPS) {
2633 Handle empty;
2634 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2635 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2636 int index = invoke_method_table()->hash_to_index(hash);
2637 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2638 if (spe != NULL && spe->method_type() != NULL) {
2639 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2640 return Handle(THREAD, spe->method_type());
2641 } else if (!THREAD->can_call_java()) {
2642 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2643 return Handle(); // do not attempt from within compiler, unless it was cached
2644 }
2645
2646 Handle class_loader, protection_domain;
2647 if (accessing_klass.not_null()) {
2648 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2649 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2650 }
2651 bool can_be_cached = true;
2652 int npts = ArgumentCount(signature).size();
2653 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2654 int arg = 0;
2655 Handle rt; // the return type from the signature
2656 ResourceMark rm(THREAD);
2657 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2658 oop mirror = NULL;
2659 if (can_be_cached) {
2660 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2661 mirror = ss.as_java_mirror(Handle(), Handle(),
2662 SignatureStream::ReturnNull, CHECK_(empty));
2663 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2664 // Fall back to accessing_klass context.
2665 can_be_cached = false;
2666 }
2667 }
2668 if (!can_be_cached) {
2669 // Resolve, throwing a real error if it doesn't work.
2670 mirror = ss.as_java_mirror(class_loader, protection_domain,
2671 SignatureStream::NCDFError, CHECK_(empty));
2672 }
2673 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2674 if (ss.at_return_type())
2675 rt = Handle(THREAD, mirror);
2676 else
2677 pts->obj_at_put(arg++, mirror);
2678
2679 // Check accessibility.
2680 if (ss.is_object() && accessing_klass.not_null()) {
2681 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2682 mirror = NULL; // safety
2683 // Emulate ConstantPool::verify_constant_pool_resolve.
2684 if (sel_klass->is_objArray_klass())
2685 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2686 if (sel_klass->is_instance_klass()) {
2687 KlassHandle sel_kh(THREAD, sel_klass);
2688 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2689 }
2690 }
2691 }
2692 assert(arg == npts, "");
2693
2694 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2695 JavaCallArguments args(Handle(THREAD, rt()));
2696 args.push_oop(pts());
2697 JavaValue result(T_OBJECT);
2698 JavaCalls::call_static(&result,
2699 SystemDictionary::MethodHandleNatives_klass(),
2700 vmSymbols::findMethodHandleType_name(),
2701 vmSymbols::findMethodHandleType_signature(),
2702 &args, CHECK_(empty));
2703 Handle method_type(THREAD, (oop) result.get_jobject());
2704
2705 if (can_be_cached) {
2706 // We can cache this MethodType inside the JVM.
2707 MutexLocker ml(SystemDictionary_lock, THREAD);
2708 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2709 if (spe == NULL)
2710 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2711 if (spe->method_type() == NULL) {
2712 spe->set_method_type(method_type());
2713 }
2714 }
2715
2716 // report back to the caller with the MethodType
2717 return method_type;
2718 }
2719
2720 // Ask Java code to find or construct a method handle constant.
2721 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2722 int ref_kind, //e.g., JVM_REF_invokeVirtual
2723 KlassHandle callee,
2724 Symbol* name_sym,
2725 Symbol* signature,
2726 TRAPS) {
2727 Handle empty;
2728 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2729 Handle type;
2730 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2731 type = find_method_handle_type(signature, caller, CHECK_(empty));
2732 } else if (caller.is_null()) {
2733 // This should not happen. JDK code should take care of that.
2734 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2735 } else {
2736 ResourceMark rm(THREAD);
2737 SignatureStream ss(signature, false);
2738 if (!ss.is_done()) {
2739 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2740 SignatureStream::NCDFError, CHECK_(empty));
2741 type = Handle(THREAD, mirror);
2742 ss.next();
2743 if (!ss.is_done()) type = Handle(); // error!
2744 }
2745 }
2746 if (type.is_null()) {
2747 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2748 }
2749
2750 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2751 JavaCallArguments args;
2752 args.push_oop(caller->java_mirror()); // the referring class
2753 args.push_int(ref_kind);
2754 args.push_oop(callee->java_mirror()); // the target class
2755 args.push_oop(name());
2756 args.push_oop(type());
2757 JavaValue result(T_OBJECT);
2758 JavaCalls::call_static(&result,
2759 SystemDictionary::MethodHandleNatives_klass(),
2760 vmSymbols::linkMethodHandleConstant_name(),
2761 vmSymbols::linkMethodHandleConstant_signature(),
2762 &args, CHECK_(empty));
2763 return Handle(THREAD, (oop) result.get_jobject());
2764 }
2765
2766 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2767 // name and signature, as interpreted relative to the given class loader.
2768 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2769 Handle bootstrap_specifier,
2770 Symbol* name,
2771 Symbol* type,
2772 Handle *appendix_result,
2773 Handle *method_type_result,
2774 TRAPS) {
2775 methodHandle empty;
2776 Handle bsm, info;
2777 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2778 bsm = bootstrap_specifier;
2779 } else {
2780 assert(bootstrap_specifier->is_objArray(), "");
2781 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2782 int len = args->length();
2783 assert(len >= 1, "");
2784 bsm = Handle(THREAD, args->obj_at(0));
2785 if (len > 1) {
2786 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2787 for (int i = 1; i < len; i++)
2788 args1->obj_at_put(i-1, args->obj_at(i));
2789 info = Handle(THREAD, args1);
2790 }
2791 }
2792 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2793 "caller must supply a valid BSM");
2794
2795 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2796 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2797
2798 // This should not happen. JDK code should take care of that.
2799 if (caller.is_null() || method_type.is_null()) {
2800 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2801 }
2802
2803 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2804 assert(appendix_box->obj_at(0) == NULL, "");
2805
2806 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2807 JavaCallArguments args;
2808 args.push_oop(caller->java_mirror());
2809 args.push_oop(bsm());
2810 args.push_oop(method_name());
2811 args.push_oop(method_type());
2812 args.push_oop(info());
2813 args.push_oop(appendix_box);
2814 JavaValue result(T_OBJECT);
2815 JavaCalls::call_static(&result,
2816 SystemDictionary::MethodHandleNatives_klass(),
2817 vmSymbols::linkCallSite_name(),
2818 vmSymbols::linkCallSite_signature(),
2819 &args, CHECK_(empty));
2820 Handle mname(THREAD, (oop) result.get_jobject());
2821 (*method_type_result) = method_type;
2822 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2823 }
2824
2825 // Since the identity hash code for symbols changes when the symbols are
2826 // moved from the regular perm gen (hash in the mark word) to the shared
2827 // spaces (hash is the address), the classes loaded into the dictionary
2828 // may be in the wrong buckets.
2829
2830 void SystemDictionary::reorder_dictionary() {
2831 dictionary()->reorder_dictionary();
2832 }
2833
2834
2835 void SystemDictionary::copy_buckets(char** top, char* end) {
2836 dictionary()->copy_buckets(top, end);
2837 }
2838
2839
2840 void SystemDictionary::copy_table(char** top, char* end) {
2841 dictionary()->copy_table(top, end);
2842 }
2843
2844
2845 void SystemDictionary::reverse() {
2846 dictionary()->reverse();
2847 }
2848
2849 int SystemDictionary::number_of_classes() {
2850 return dictionary()->number_of_entries();
2851 }
2852
2853
2854 // ----------------------------------------------------------------------------
2855 void SystemDictionary::print_shared(bool details) {
2856 shared_dictionary()->print(details);
2857 }
2858
2859 void SystemDictionary::print(bool details) {
2860 dictionary()->print(details);
2861
2862 // Placeholders
2863 GCMutexLocker mu(SystemDictionary_lock);
2864 placeholders()->print();
2865
2866 // loader constraints - print under SD_lock
2867 constraints()->print();
2868 }
2869
2870
2871 void SystemDictionary::verify() {
2872 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2873 guarantee(constraints() != NULL,
2874 "Verify of loader constraints failed");
2875 guarantee(dictionary()->number_of_entries() >= 0 &&
2876 placeholders()->number_of_entries() >= 0,
2877 "Verify of system dictionary failed");
2878
2879 // Verify dictionary
2880 dictionary()->verify();
2881
2882 GCMutexLocker mu(SystemDictionary_lock);
2883 placeholders()->verify();
2884
2885 // Verify constraint table
2886 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2887 constraints()->verify(dictionary(), placeholders());
2888 }
2889
2890 // caller needs ResourceMark
2891 const char* SystemDictionary::loader_name(const oop loader) {
2892 return ((loader) == NULL ? "<bootloader>" :
2893 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2894 }
2895
2896 // caller needs ResourceMark
2897 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2898 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2899 SystemDictionary::loader_name(loader_data->class_loader()));
2900 }