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