1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/resolutionErrors.hpp"
39 #include "classfile/stringTable.hpp"
40 #include "classfile/systemDictionary.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "code/codeCache.hpp"
43 #include "compiler/compileBroker.hpp"
44 #include "gc/shared/gcLocker.hpp"
45 #include "gc/shared/gcTraceTime.inline.hpp"
46 #include "interpreter/bytecodeStream.hpp"
47 #include "interpreter/interpreter.hpp"
48 #include "logging/log.hpp"
49 #include "memory/filemap.hpp"
50 #include "memory/oopFactory.hpp"
51 #include "memory/resourceArea.hpp"
52 #include "oops/instanceKlass.hpp"
53 #include "oops/instanceRefKlass.hpp"
54 #include "oops/klass.inline.hpp"
55 #include "oops/methodData.hpp"
56 #include "oops/objArrayKlass.hpp"
57 #include "oops/objArrayOop.inline.hpp"
58 #include "oops/oop.inline.hpp"
59 #include "oops/symbol.hpp"
60 #include "oops/typeArrayKlass.hpp"
61 #include "prims/jvmtiEnvBase.hpp"
62 #include "prims/resolvedMethodTable.hpp"
63 #include "prims/methodHandles.hpp"
64 #include "runtime/arguments.hpp"
65 #include "runtime/biasedLocking.hpp"
66 #include "runtime/fieldType.hpp"
67 #include "runtime/handles.inline.hpp"
68 #include "runtime/java.hpp"
69 #include "runtime/javaCalls.hpp"
70 #include "runtime/mutexLocker.hpp"
71 #include "runtime/orderAccess.inline.hpp"
72 #include "runtime/signature.hpp"
73 #include "services/classLoadingService.hpp"
74 #include "services/threadService.hpp"
75 #include "utilities/macros.hpp"
76 #if INCLUDE_CDS
77 #include "classfile/sharedClassUtil.hpp"
78 #include "classfile/systemDictionaryShared.hpp"
79 #endif
80 #if INCLUDE_JVMCI
81 #include "jvmci/jvmciRuntime.hpp"
82 #endif
83 #if INCLUDE_TRACE
84 #include "trace/tracing.hpp"
85 #endif
86
87 Dictionary* SystemDictionary::_dictionary = NULL;
88 PlaceholderTable* SystemDictionary::_placeholders = NULL;
89 Dictionary* SystemDictionary::_shared_dictionary = NULL;
90 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
91 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
92 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
93
94
95 int SystemDictionary::_number_of_modifications = 0;
96 int SystemDictionary::_sdgeneration = 0;
97 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
98 20201,40423,99991};
99
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108
109 bool SystemDictionary::_has_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115
116 // ----------------------------------------------------------------------------
117 // Java-level SystemLoader
118
119 oop SystemDictionary::java_system_loader() {
120 return _java_system_loader;
121 }
122
123 void SystemDictionary::compute_java_system_loader(TRAPS) {
124 Klass* system_klass = WK_KLASS(ClassLoader_klass);
125 JavaValue result(T_OBJECT);
126 JavaCalls::call_static(&result,
127 WK_KLASS(ClassLoader_klass),
128 vmSymbols::getSystemClassLoader_name(),
129 vmSymbols::void_classloader_signature(),
130 CHECK);
131
132 _java_system_loader = (oop)result.get_jobject();
133
134 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
135 }
136
137
138 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
139 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
140 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
141 }
142
143 // ----------------------------------------------------------------------------
144 // Parallel class loading check
145
146 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
147 if (UnsyncloadClass || class_loader.is_null()) return true;
148 if (AlwaysLockClassLoader) return false;
149 return java_lang_ClassLoader::parallelCapable(class_loader());
150 }
151 // ----------------------------------------------------------------------------
152 // ParallelDefineClass flag does not apply to bootclass loader
153 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
154 if (class_loader.is_null()) return false;
155 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
156 return true;
157 }
158 return false;
159 }
160
161 // Returns true if the passed class loader is the builtin application class loader
162 // or a custom system class loader. A customer system class loader can be
163 // specified via -Djava.system.class.loader.
164 bool SystemDictionary::is_system_class_loader(oop class_loader) {
165 if (class_loader == NULL) {
166 return false;
167 }
168 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
169 class_loader == _java_system_loader);
170 }
171
172 // Returns true if the passed class loader is the platform class loader.
173 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
174 if (class_loader == NULL) {
175 return false;
176 }
177 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
178 }
179
180 // ----------------------------------------------------------------------------
181 // Resolving of classes
182
183 // Forwards to resolve_or_null
184
185 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
186 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
187 if (HAS_PENDING_EXCEPTION || klass == NULL) {
188 // can return a null klass
189 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
190 }
191 return klass;
192 }
193
194 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
195 bool throw_error,
196 Klass* klass, TRAPS) {
197 if (HAS_PENDING_EXCEPTION) {
198 // If we have a pending exception we forward it to the caller, unless throw_error is true,
199 // in which case we have to check whether the pending exception is a ClassNotFoundException,
200 // and if so convert it to a NoClassDefFoundError
201 // And chain the original ClassNotFoundException
202 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
203 ResourceMark rm(THREAD);
204 assert(klass == NULL, "Should not have result with exception pending");
205 Handle e(THREAD, PENDING_EXCEPTION);
206 CLEAR_PENDING_EXCEPTION;
207 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
208 } else {
209 return NULL;
210 }
211 }
212 // Class not found, throw appropriate error or exception depending on value of throw_error
213 if (klass == NULL) {
214 ResourceMark rm(THREAD);
215 if (throw_error) {
216 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
217 } else {
218 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
219 }
220 }
221 return klass;
222 }
223
224
225 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
226 bool throw_error, TRAPS)
227 {
228 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
229 }
230
231
232 // Forwards to resolve_instance_class_or_null
233
234 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
235 assert(THREAD->can_call_java(),
236 "can not load classes with compiler thread: class=%s, classloader=%s",
237 class_name->as_C_string(),
238 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
239 if (FieldType::is_array(class_name)) {
240 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
241 } else if (FieldType::is_obj(class_name)) {
242 ResourceMark rm(THREAD);
243 // Ignore wrapping L and ;.
244 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
245 class_name->utf8_length() - 2, CHECK_NULL);
246 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
247 } else {
248 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
249 }
250 }
251
252 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
253 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
254 }
255
256 // Forwards to resolve_instance_class_or_null
257
258 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
259 Handle class_loader,
260 Handle protection_domain,
261 TRAPS) {
262 assert(FieldType::is_array(class_name), "must be array");
263 Klass* k = NULL;
264 FieldArrayInfo fd;
265 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
266 // of this call
267 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
268 if (t == T_OBJECT) {
269 // naked oop "k" is OK here -- we assign back into it
270 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
271 class_loader,
272 protection_domain,
273 CHECK_NULL);
274 if (k != NULL) {
275 k = k->array_klass(fd.dimension(), CHECK_NULL);
276 }
277 } else {
278 k = Universe::typeArrayKlassObj(t);
279 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
280 }
281 return k;
282 }
283
284
285 // Must be called for any super-class or super-interface resolution
286 // during class definition to allow class circularity checking
287 // super-interface callers:
288 // parse_interfaces - for defineClass & jvmtiRedefineClasses
289 // super-class callers:
290 // ClassFileParser - for defineClass & jvmtiRedefineClasses
291 // load_shared_class - while loading a class from shared archive
292 // resolve_instance_class_or_null:
293 // via: handle_parallel_super_load
294 // when resolving a class that has an existing placeholder with
295 // a saved superclass [i.e. a defineClass is currently in progress]
296 // if another thread is trying to resolve the class, it must do
297 // super-class checks on its own thread to catch class circularity
298 // This last call is critical in class circularity checking for cases
299 // where classloading is delegated to different threads and the
300 // classloader lock is released.
301 // Take the case: Base->Super->Base
302 // 1. If thread T1 tries to do a defineClass of class Base
303 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
304 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
305 // so it tries to load Super
306 // 3. If we load the class internally, or user classloader uses same thread
307 // loadClassFromxxx or defineClass via parseClassFile Super ...
308 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
309 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
310 // 3.4 calls resolve_super_or_fail Base
311 // 3.5 finds T1,Base -> throws class circularity
312 //OR 4. If T2 tries to resolve Super via defineClass Super ...
313 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
314 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
315 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
316 // 4.4 finds T2, Super -> throws class circularity
317 // Must be called, even if superclass is null, since this is
318 // where the placeholder entry is created which claims this
319 // thread is loading this class/classloader.
320 // Be careful when modifying this code: once you have run
321 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
322 // you need to find_and_remove it before returning.
323 // So be careful to not exit with a CHECK_ macro betweeen these calls.
324 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
325 Symbol* class_name,
326 Handle class_loader,
327 Handle protection_domain,
328 bool is_superclass,
329 TRAPS) {
330 #if INCLUDE_CDS
331 if (DumpSharedSpaces) {
332 // Special processing for CDS dump time.
333 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
334 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
335 if (k) {
336 return k;
337 }
338 }
339 #endif // INCLUDE_CDS
340
341 // Double-check, if child class is already loaded, just return super-class,interface
342 // Don't add a placedholder if already loaded, i.e. already in system dictionary
343 // Make sure there's a placeholder for the *child* before resolving.
344 // Used as a claim that this thread is currently loading superclass/classloader
345 // Used here for ClassCircularity checks and also for heap verification
346 // (every InstanceKlass in the heap needs to be in the system dictionary
347 // or have a placeholder).
348 // Must check ClassCircularity before checking if super class is already loaded
349 //
350 // We might not already have a placeholder if this child_name was
351 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
352 // the name of the class might not be known until the stream is actually
353 // parsed.
354 // Bugs 4643874, 4715493
355 // compute_hash can have a safepoint
356
357 ClassLoaderData* loader_data = class_loader_data(class_loader);
358 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
359 int d_index = dictionary()->hash_to_index(d_hash);
360 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
361 int p_index = placeholders()->hash_to_index(p_hash);
362 // can't throw error holding a lock
363 bool child_already_loaded = false;
364 bool throw_circularity_error = false;
365 {
366 MutexLocker mu(SystemDictionary_lock, THREAD);
367 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
368 Klass* quicksuperk;
369 // to support // loading: if child done loading, just return superclass
370 // if class_name, & class_loader don't match:
371 // if initial define, SD update will give LinkageError
372 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
373 // so we don't throw an exception here.
374 // see: nsk redefclass014 & java.lang.instrument Instrument032
375 if ((childk != NULL ) && (is_superclass) &&
376 ((quicksuperk = childk->super()) != NULL) &&
377
378 ((quicksuperk->name() == class_name) &&
379 (quicksuperk->class_loader() == class_loader()))) {
380 return quicksuperk;
381 } else {
382 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
383 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
384 throw_circularity_error = true;
385 }
386 }
387 if (!throw_circularity_error) {
388 // Be careful not to exit resolve_super
389 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
390 }
391 }
392 if (throw_circularity_error) {
393 ResourceMark rm(THREAD);
394 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
395 }
396
397 // java.lang.Object should have been found above
398 assert(class_name != NULL, "null super class for resolving");
399 // Resolve the super class or interface, check results on return
400 Klass* superk = SystemDictionary::resolve_or_null(class_name,
401 class_loader,
402 protection_domain,
403 THREAD);
404
405 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
406 // It is no longer necessary to keep the placeholder table alive until update_dictionary
407 // or error. GC used to walk the placeholder table as strong roots.
408 // The instanceKlass is kept alive because the class loader is on the stack,
409 // which keeps the loader_data alive, as well as all instanceKlasses in
410 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
411 {
412 MutexLocker mu(SystemDictionary_lock, THREAD);
413 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
414 SystemDictionary_lock->notify_all();
415 }
416 if (HAS_PENDING_EXCEPTION || superk == NULL) {
417 // can null superk
418 superk = handle_resolution_exception(class_name, true, superk, THREAD);
419 }
420
421 return superk;
422 }
423
424 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
425 Handle class_loader,
426 Handle protection_domain,
427 TRAPS) {
428 if(!has_checkPackageAccess()) return;
429
430 // Now we have to call back to java to check if the initating class has access
431 JavaValue result(T_VOID);
432 if (log_is_enabled(Debug, protectiondomain)) {
433 ResourceMark rm;
434 // Print out trace information
435 outputStream* log = Log(protectiondomain)::debug_stream();
436 log->print_cr("Checking package access");
437 log->print("class loader: "); class_loader()->print_value_on(log);
438 log->print(" protection domain: "); protection_domain()->print_value_on(log);
439 log->print(" loading: "); klass->print_value_on(log);
440 log->cr();
441 }
442
443 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
444 JavaCalls::call_special(&result,
445 class_loader,
446 system_loader,
447 vmSymbols::checkPackageAccess_name(),
448 vmSymbols::class_protectiondomain_signature(),
449 Handle(THREAD, klass->java_mirror()),
450 protection_domain,
451 THREAD);
452
453 if (HAS_PENDING_EXCEPTION) {
454 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
455 } else {
456 log_debug(protectiondomain)("granted");
457 }
458
459 if (HAS_PENDING_EXCEPTION) return;
460
461 // If no exception has been thrown, we have validated the protection domain
462 // Insert the protection domain of the initiating class into the set.
463 {
464 // We recalculate the entry here -- we've called out to java since
465 // the last time it was calculated.
466 ClassLoaderData* loader_data = class_loader_data(class_loader);
467
468 Symbol* kn = klass->name();
469 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
470 int d_index = dictionary()->hash_to_index(d_hash);
471
472 MutexLocker mu(SystemDictionary_lock, THREAD);
473 {
474 // Note that we have an entry, and entries can be deleted only during GC,
475 // so we cannot allow GC to occur while we're holding this entry.
476
477 // We're using a NoSafepointVerifier to catch any place where we
478 // might potentially do a GC at all.
479 // Dictionary::do_unloading() asserts that classes in SD are only
480 // unloaded at a safepoint. Anonymous classes are not in SD.
481 NoSafepointVerifier nosafepoint;
482 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
483 protection_domain, THREAD);
484 }
485 }
486 }
487
488 // We only get here if this thread finds that another thread
489 // has already claimed the placeholder token for the current operation,
490 // but that other thread either never owned or gave up the
491 // object lock
492 // Waits on SystemDictionary_lock to indicate placeholder table updated
493 // On return, caller must recheck placeholder table state
494 //
495 // We only get here if
496 // 1) custom classLoader, i.e. not bootstrap classloader
497 // 2) UnsyncloadClass not set
498 // 3) custom classLoader has broken the class loader objectLock
499 // so another thread got here in parallel
500 //
501 // lockObject must be held.
502 // Complicated dance due to lock ordering:
503 // Must first release the classloader object lock to
504 // allow initial definer to complete the class definition
505 // and to avoid deadlock
506 // Reclaim classloader lock object with same original recursion count
507 // Must release SystemDictionary_lock after notify, since
508 // class loader lock must be claimed before SystemDictionary_lock
509 // to prevent deadlocks
510 //
511 // The notify allows applications that did an untimed wait() on
512 // the classloader object lock to not hang.
513 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
514 assert_lock_strong(SystemDictionary_lock);
515
516 bool calledholdinglock
517 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
518 assert(calledholdinglock,"must hold lock for notify");
519 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
520 ObjectSynchronizer::notifyall(lockObject, THREAD);
521 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
522 SystemDictionary_lock->wait();
523 SystemDictionary_lock->unlock();
524 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
525 SystemDictionary_lock->lock();
526 }
527
528 // If the class in is in the placeholder table, class loading is in progress
529 // For cases where the application changes threads to load classes, it
530 // is critical to ClassCircularity detection that we try loading
531 // the superclass on the same thread internally, so we do parallel
532 // super class loading here.
533 // This also is critical in cases where the original thread gets stalled
534 // even in non-circularity situations.
535 // Note: must call resolve_super_or_fail even if null super -
536 // to force placeholder entry creation for this class for circularity detection
537 // Caller must check for pending exception
538 // Returns non-null Klass* if other thread has completed load
539 // and we are done,
540 // If return null Klass* and no pending exception, the caller must load the class
541 InstanceKlass* SystemDictionary::handle_parallel_super_load(
542 Symbol* name, Symbol* superclassname, Handle class_loader,
543 Handle protection_domain, Handle lockObject, TRAPS) {
544
545 ClassLoaderData* loader_data = class_loader_data(class_loader);
546 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
547 int d_index = dictionary()->hash_to_index(d_hash);
548 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
549 int p_index = placeholders()->hash_to_index(p_hash);
550
551 // superk is not used, resolve_super called for circularity check only
552 // This code is reached in two situations. One if this thread
553 // is loading the same class twice (e.g. ClassCircularity, or
554 // java.lang.instrument).
555 // The second is if another thread started the resolve_super first
556 // and has not yet finished.
557 // In both cases the original caller will clean up the placeholder
558 // entry on error.
559 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
560 superclassname,
561 class_loader,
562 protection_domain,
563 true,
564 CHECK_NULL);
565
566 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
567 // Serial class loaders and bootstrap classloader do wait for superclass loads
568 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
569 MutexLocker mu(SystemDictionary_lock, THREAD);
570 // Check if classloading completed while we were loading superclass or waiting
571 return find_class(d_index, d_hash, name, loader_data);
572 }
573
574 // must loop to both handle other placeholder updates
575 // and spurious notifications
576 bool super_load_in_progress = true;
577 PlaceholderEntry* placeholder;
578 while (super_load_in_progress) {
579 MutexLocker mu(SystemDictionary_lock, THREAD);
580 // Check if classloading completed while we were loading superclass or waiting
581 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
582 if (check != NULL) {
583 // Klass is already loaded, so just return it
584 return check;
585 } else {
586 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
587 if (placeholder && placeholder->super_load_in_progress() ){
588 // Before UnsyncloadClass:
589 // We only get here if the application has released the
590 // classloader lock when another thread was in the middle of loading a
591 // superclass/superinterface for this class, and now
592 // this thread is also trying to load this class.
593 // To minimize surprises, the first thread that started to
594 // load a class should be the one to complete the loading
595 // with the classfile it initially expected.
596 // This logic has the current thread wait once it has done
597 // all the superclass/superinterface loading it can, until
598 // the original thread completes the class loading or fails
599 // If it completes we will use the resulting InstanceKlass
600 // which we will find below in the systemDictionary.
601 // We also get here for parallel bootstrap classloader
602 if (class_loader.is_null()) {
603 SystemDictionary_lock->wait();
604 } else {
605 double_lock_wait(lockObject, THREAD);
606 }
607 } else {
608 // If not in SD and not in PH, other thread's load must have failed
609 super_load_in_progress = false;
610 }
611 }
612 }
613 return NULL;
614 }
615
616 #if INCLUDE_TRACE
617 static void post_class_load_event(EventClassLoad* event,
618 const InstanceKlass* k,
619 const ClassLoaderData* init_cld) {
620 assert(event != NULL, "invariant");
621 assert(k != NULL, "invariant");
622
623 if (event->should_commit()) {
624 event->set_loadedClass(k);
625 //event->set_definingClassLoader(k->class_loader_data());
626 event->set_initiatingClassLoader(init_cld);
627 event->commit();
628 }
629 }
630
631 static void post_class_define_event(const InstanceKlass* k,
632 const ClassLoaderData* def_cld) {
633 EventClassDefine event;
634 if (event.should_commit()) {
635 event.set_definedClass(k);
636 event.set_definingClassLoader(def_cld);
637 event.commit();
638 }
639 }
640 #endif // INCLUDE_TRACE
641
642 // Be careful when modifying this code: once you have run
643 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
644 // you need to find_and_remove it before returning.
645 // So be careful to not exit with a CHECK_ macro betweeen these calls.
646 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
647 Handle class_loader,
648 Handle protection_domain,
649 TRAPS) {
650 assert(name != NULL && !FieldType::is_array(name) &&
651 !FieldType::is_obj(name), "invalid class name");
652
653 TRACE_ONLY(EventClassLoad ev;)
654
655 HandleMark hm(THREAD);
656
657 // Fix for 4474172; see evaluation for more details
658 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
659 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
660
661 // Do lookup to see if class already exist and the protection domain
662 // has the right access
663 // This call uses find which checks protection domain already matches
664 // All subsequent calls use find_class, and set has_loaded_class so that
665 // before we return a result we call out to java to check for valid protection domain
666 // to allow returning the Klass* and add it to the pd_set if it is valid
667 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
668 int d_index = dictionary()->hash_to_index(d_hash);
669 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
670 protection_domain, THREAD);
671 if (probe != NULL) return probe;
672
673
674 // Non-bootstrap class loaders will call out to class loader and
675 // define via jvm/jni_DefineClass which will acquire the
676 // class loader object lock to protect against multiple threads
677 // defining the class in parallel by accident.
678 // This lock must be acquired here so the waiter will find
679 // any successful result in the SystemDictionary and not attempt
680 // the define
681 // ParallelCapable Classloaders and the bootstrap classloader,
682 // or all classloaders with UnsyncloadClass do not acquire lock here
683 bool DoObjectLock = true;
684 if (is_parallelCapable(class_loader)) {
685 DoObjectLock = false;
686 }
687
688 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
689 int p_index = placeholders()->hash_to_index(p_hash);
690
691 // Class is not in SystemDictionary so we have to do loading.
692 // Make sure we are synchronized on the class loader before we proceed
693 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
694 check_loader_lock_contention(lockObject, THREAD);
695 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
696
697 // Check again (after locking) if class already exist in SystemDictionary
698 bool class_has_been_loaded = false;
699 bool super_load_in_progress = false;
700 bool havesupername = false;
701 InstanceKlass* k = NULL;
702 PlaceholderEntry* placeholder;
703 Symbol* superclassname = NULL;
704
705 {
706 MutexLocker mu(SystemDictionary_lock, THREAD);
707 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
708 if (check != NULL) {
709 // Klass is already loaded, so just return it
710 class_has_been_loaded = true;
711 k = check;
712 } else {
713 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
714 if (placeholder && placeholder->super_load_in_progress()) {
715 super_load_in_progress = true;
716 if (placeholder->havesupername() == true) {
717 superclassname = placeholder->supername();
718 havesupername = true;
719 }
720 }
721 }
722 }
723
724 // If the class is in the placeholder table, class loading is in progress
725 if (super_load_in_progress && havesupername==true) {
726 k = handle_parallel_super_load(name,
727 superclassname,
728 class_loader,
729 protection_domain,
730 lockObject, THREAD);
731 if (HAS_PENDING_EXCEPTION) {
732 return NULL;
733 }
734 if (k != NULL) {
735 class_has_been_loaded = true;
736 }
737 }
738
739 bool throw_circularity_error = false;
740 if (!class_has_been_loaded) {
741 bool load_instance_added = false;
742
743 // add placeholder entry to record loading instance class
744 // Five cases:
745 // All cases need to prevent modifying bootclasssearchpath
746 // in parallel with a classload of same classname
747 // Redefineclasses uses existence of the placeholder for the duration
748 // of the class load to prevent concurrent redefinition of not completely
749 // defined classes.
750 // case 1. traditional classloaders that rely on the classloader object lock
751 // - no other need for LOAD_INSTANCE
752 // case 2. traditional classloaders that break the classloader object lock
753 // as a deadlock workaround. Detection of this case requires that
754 // this check is done while holding the classloader object lock,
755 // and that lock is still held when calling classloader's loadClass.
756 // For these classloaders, we ensure that the first requestor
757 // completes the load and other requestors wait for completion.
758 // case 3. UnsyncloadClass - don't use objectLocker
759 // With this flag, we allow parallel classloading of a
760 // class/classloader pair
761 // case4. Bootstrap classloader - don't own objectLocker
762 // This classloader supports parallelism at the classloader level,
763 // but only allows a single load of a class/classloader pair.
764 // No performance benefit and no deadlock issues.
765 // case 5. parallelCapable user level classloaders - without objectLocker
766 // Allow parallel classloading of a class/classloader pair
767
768 {
769 MutexLocker mu(SystemDictionary_lock, THREAD);
770 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
771 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
772 if (oldprobe) {
773 // only need check_seen_thread once, not on each loop
774 // 6341374 java/lang/Instrument with -Xcomp
775 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
776 throw_circularity_error = true;
777 } else {
778 // case 1: traditional: should never see load_in_progress.
779 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
780
781 // case 4: bootstrap classloader: prevent futile classloading,
782 // wait on first requestor
783 if (class_loader.is_null()) {
784 SystemDictionary_lock->wait();
785 } else {
786 // case 2: traditional with broken classloader lock. wait on first
787 // requestor.
788 double_lock_wait(lockObject, THREAD);
789 }
790 // Check if classloading completed while we were waiting
791 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
792 if (check != NULL) {
793 // Klass is already loaded, so just return it
794 k = check;
795 class_has_been_loaded = true;
796 }
797 // check if other thread failed to load and cleaned up
798 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
799 }
800 }
801 }
802 }
803 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
804 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
805 // LOAD_INSTANCE in parallel
806
807 if (!throw_circularity_error && !class_has_been_loaded) {
808 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
809 load_instance_added = true;
810 // For class loaders that do not acquire the classloader object lock,
811 // if they did not catch another thread holding LOAD_INSTANCE,
812 // need a check analogous to the acquire ObjectLocker/find_class
813 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
814 // one final check if the load has already completed
815 // class loaders holding the ObjectLock shouldn't find the class here
816 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
817 if (check != NULL) {
818 // Klass is already loaded, so return it after checking/adding protection domain
819 k = check;
820 class_has_been_loaded = true;
821 }
822 }
823 }
824
825 // must throw error outside of owning lock
826 if (throw_circularity_error) {
827 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
828 ResourceMark rm(THREAD);
829 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
830 }
831
832 if (!class_has_been_loaded) {
833
834 // Do actual loading
835 k = load_instance_class(name, class_loader, THREAD);
836
837 // For UnsyncloadClass only
838 // If they got a linkageError, check if a parallel class load succeeded.
839 // If it did, then for bytecode resolution the specification requires
840 // that we return the same result we did for the other thread, i.e. the
841 // successfully loaded InstanceKlass
842 // Should not get here for classloaders that support parallelism
843 // with the new cleaner mechanism, even with AllowParallelDefineClass
844 // Bootstrap goes through here to allow for an extra guarantee check
845 if (UnsyncloadClass || (class_loader.is_null())) {
846 if (k == NULL && HAS_PENDING_EXCEPTION
847 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
850 if (check != NULL) {
851 // Klass is already loaded, so just use it
852 k = check;
853 CLEAR_PENDING_EXCEPTION;
854 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
855 }
856 }
857 }
858
859 // If everything was OK (no exceptions, no null return value), and
860 // class_loader is NOT the defining loader, do a little more bookkeeping.
861 if (!HAS_PENDING_EXCEPTION && k != NULL &&
862 k->class_loader() != class_loader()) {
863
864 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
865
866 // Need to check for a PENDING_EXCEPTION again; check_constraints
867 // can throw and doesn't use the CHECK macro.
868 if (!HAS_PENDING_EXCEPTION) {
869 { // Grabbing the Compile_lock prevents systemDictionary updates
870 // during compilations.
871 MutexLocker mu(Compile_lock, THREAD);
872 update_dictionary(d_index, d_hash, p_index, p_hash,
873 k, class_loader, THREAD);
874 }
875
876 if (JvmtiExport::should_post_class_load()) {
877 Thread *thread = THREAD;
878 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
879 JvmtiExport::post_class_load((JavaThread *) thread, k);
880 }
881 }
882 }
883 } // load_instance_class loop
884
885 if (load_instance_added == true) {
886 // clean up placeholder entries for LOAD_INSTANCE success or error
887 // This brackets the SystemDictionary updates for both defining
888 // and initiating loaders
889 MutexLocker mu(SystemDictionary_lock, THREAD);
890 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
891 SystemDictionary_lock->notify_all();
892 }
893 }
894
895 if (HAS_PENDING_EXCEPTION || k == NULL) {
896 return NULL;
897 }
898
899 TRACE_ONLY(post_class_load_event(&ev, k, loader_data);)
900
901 #ifdef ASSERT
902 {
903 ClassLoaderData* loader_data = k->class_loader_data();
904 MutexLocker mu(SystemDictionary_lock, THREAD);
905 Klass* kk = find_class(name, loader_data);
906 assert(kk == k, "should be present in dictionary");
907 }
908 #endif
909
910 // return if the protection domain in NULL
911 if (protection_domain() == NULL) return k;
912
913 // Check the protection domain has the right access
914 {
915 MutexLocker mu(SystemDictionary_lock, THREAD);
916 // Note that we have an entry, and entries can be deleted only during GC,
917 // so we cannot allow GC to occur while we're holding this entry.
918 // We're using a NoSafepointVerifier to catch any place where we
919 // might potentially do a GC at all.
920 // Dictionary::do_unloading() asserts that classes in SD are only
921 // unloaded at a safepoint. Anonymous classes are not in SD.
922 NoSafepointVerifier nosafepoint;
923 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
924 loader_data,
925 protection_domain)) {
926 return k;
927 }
928 }
929
930 // Verify protection domain. If it fails an exception is thrown
931 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
932
933 return k;
934 }
935
936
937 // This routine does not lock the system dictionary.
938 //
939 // Since readers don't hold a lock, we must make sure that system
940 // dictionary entries are only removed at a safepoint (when only one
941 // thread is running), and are added to in a safe way (all links must
942 // be updated in an MT-safe manner).
943 //
944 // Callers should be aware that an entry could be added just after
945 // _dictionary->bucket(index) is read here, so the caller will not see
946 // the new entry.
947
948 Klass* SystemDictionary::find(Symbol* class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 TRAPS) {
952
953 // The result of this call should be consistent with the result
954 // of the call to resolve_instance_class_or_null().
955 // See evaluation 6790209 and 4474172 for more details.
956 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
957 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
958
959 if (loader_data == NULL) {
960 // If the ClassLoaderData has not been setup,
961 // then the class loader has no entries in the dictionary.
962 return NULL;
963 }
964
965 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
966 int d_index = dictionary()->hash_to_index(d_hash);
967
968 {
969 // Note that we have an entry, and entries can be deleted only during GC,
970 // so we cannot allow GC to occur while we're holding this entry.
971 // We're using a NoSafepointVerifier to catch any place where we
972 // might potentially do a GC at all.
973 // Dictionary::do_unloading() asserts that classes in SD are only
974 // unloaded at a safepoint. Anonymous classes are not in SD.
975 NoSafepointVerifier nosafepoint;
976 return dictionary()->find(d_index, d_hash, class_name, loader_data,
977 protection_domain, THREAD);
978 }
979 }
980
981
982 // Look for a loaded instance or array klass by name. Do not do any loading.
983 // return NULL in case of error.
984 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
985 Handle class_loader,
986 Handle protection_domain,
987 TRAPS) {
988 Klass* k = NULL;
989 assert(class_name != NULL, "class name must be non NULL");
990
991 if (FieldType::is_array(class_name)) {
992 // The name refers to an array. Parse the name.
993 // dimension and object_key in FieldArrayInfo are assigned as a
994 // side-effect of this call
995 FieldArrayInfo fd;
996 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
997 if (t != T_OBJECT) {
998 k = Universe::typeArrayKlassObj(t);
999 } else {
1000 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1001 }
1002 if (k != NULL) {
1003 k = k->array_klass_or_null(fd.dimension());
1004 }
1005 } else {
1006 k = find(class_name, class_loader, protection_domain, THREAD);
1007 }
1008 return k;
1009 }
1010
1011 // Note: this method is much like resolve_from_stream, but
1012 // does not publish the classes via the SystemDictionary.
1013 // Handles unsafe_DefineAnonymousClass and redefineclasses
1014 // RedefinedClasses do not add to the class hierarchy
1015 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1016 Handle class_loader,
1017 Handle protection_domain,
1018 ClassFileStream* st,
1019 const InstanceKlass* host_klass,
1020 GrowableArray<Handle>* cp_patches,
1021 TRAPS) {
1022 TRACE_ONLY(EventClassLoad ev;)
1023
1024 ClassLoaderData* loader_data;
1025 if (host_klass != NULL) {
1026 // Create a new CLD for anonymous class, that uses the same class loader
1027 // as the host_klass
1028 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1029 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1030 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1031 loader_data->record_dependency(host_klass, CHECK_NULL);
1032 } else {
1033 loader_data = ClassLoaderData::class_loader_data(class_loader());
1034 }
1035
1036 assert(st != NULL, "invariant");
1037 assert(st->need_verify(), "invariant");
1038
1039 // Parse stream and create a klass.
1040 // Note that we do this even though this klass might
1041 // already be present in the SystemDictionary, otherwise we would not
1042 // throw potential ClassFormatErrors.
1043
1044 InstanceKlass* k = KlassFactory::create_from_stream(st,
1045 class_name,
1046 loader_data,
1047 protection_domain,
1048 host_klass,
1049 cp_patches,
1050 CHECK_NULL);
1051
1052 if (host_klass != NULL && k != NULL) {
1053 // If it's anonymous, initialize it now, since nobody else will.
1054
1055 {
1056 MutexLocker mu_r(Compile_lock, THREAD);
1057
1058 // Add to class hierarchy, initialize vtables, and do possible
1059 // deoptimizations.
1060 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1061
1062 // But, do not add to system dictionary.
1063
1064 // compiled code dependencies need to be validated anyway
1065 notice_modification();
1066 }
1067
1068 // Rewrite and patch constant pool here.
1069 k->link_class(CHECK_NULL);
1070 if (cp_patches != NULL) {
1071 k->constants()->patch_resolved_references(cp_patches);
1072 }
1073 k->eager_initialize(CHECK_NULL);
1074
1075 // notify jvmti
1076 if (JvmtiExport::should_post_class_load()) {
1077 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1078 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1079 }
1080
1081 TRACE_ONLY(post_class_load_event(&ev, k, loader_data);)
1082 }
1083 assert(host_klass != NULL || NULL == cp_patches,
1084 "cp_patches only found with host_klass");
1085
1086 return k;
1087 }
1088
1089 // Add a klass to the system from a stream (called by jni_DefineClass and
1090 // JVM_DefineClass).
1091 // Note: class_name can be NULL. In that case we do not know the name of
1092 // the class until we have parsed the stream.
1093
1094 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1095 Handle class_loader,
1096 Handle protection_domain,
1097 ClassFileStream* st,
1098 TRAPS) {
1099
1100 HandleMark hm(THREAD);
1101
1102 // Classloaders that support parallelism, e.g. bootstrap classloader,
1103 // or all classloaders with UnsyncloadClass do not acquire lock here
1104 bool DoObjectLock = true;
1105 if (is_parallelCapable(class_loader)) {
1106 DoObjectLock = false;
1107 }
1108
1109 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1110
1111 // Make sure we are synchronized on the class loader before we proceed
1112 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1113 check_loader_lock_contention(lockObject, THREAD);
1114 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1115
1116 assert(st != NULL, "invariant");
1117
1118 // Parse the stream and create a klass.
1119 // Note that we do this even though this klass might
1120 // already be present in the SystemDictionary, otherwise we would not
1121 // throw potential ClassFormatErrors.
1122 InstanceKlass* k = NULL;
1123
1124 #if INCLUDE_CDS
1125 k = SystemDictionaryShared::lookup_from_stream(class_name,
1126 class_loader,
1127 protection_domain,
1128 st,
1129 CHECK_NULL);
1130 #endif
1131
1132 if (k == NULL) {
1133 if (st->buffer() == NULL) {
1134 return NULL;
1135 }
1136 k = KlassFactory::create_from_stream(st,
1137 class_name,
1138 loader_data,
1139 protection_domain,
1140 NULL, // host_klass
1141 NULL, // cp_patches
1142 CHECK_NULL);
1143 }
1144
1145 assert(k != NULL, "no klass created");
1146 Symbol* h_name = k->name();
1147 assert(class_name == NULL || class_name == h_name, "name mismatch");
1148
1149 // Add class just loaded
1150 // If a class loader supports parallel classloading handle parallel define requests
1151 // find_or_define_instance_class may return a different InstanceKlass
1152 if (is_parallelCapable(class_loader)) {
1153 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1154 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1155 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1156 assert(defined_k != NULL, "Should have a klass if there's no exception");
1157 loader_data->add_to_deallocate_list(k);
1158 k = defined_k;
1159 }
1160 } else {
1161 define_instance_class(k, THREAD);
1162 }
1163
1164 // If defining the class throws an exception register 'k' for cleanup.
1165 if (HAS_PENDING_EXCEPTION) {
1166 assert(k != NULL, "Must have an instance klass here!");
1167 loader_data->add_to_deallocate_list(k);
1168 return NULL;
1169 }
1170
1171 // Make sure we have an entry in the SystemDictionary on success
1172 debug_only( {
1173 MutexLocker mu(SystemDictionary_lock, THREAD);
1174
1175 Klass* check = find_class(h_name, k->class_loader_data());
1176 assert(check == k, "should be present in the dictionary");
1177 } );
1178
1179 return k;
1180 }
1181
1182 #if INCLUDE_CDS
1183 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1184 int number_of_entries) {
1185 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1186 "bad shared dictionary size.");
1187 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1188 }
1189
1190
1191 // If there is a shared dictionary, then find the entry for the
1192 // given shared system class, if any.
1193
1194 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1195 if (shared_dictionary() != NULL) {
1196 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1197 int d_index = shared_dictionary()->hash_to_index(d_hash);
1198
1199 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1200 } else {
1201 return NULL;
1202 }
1203 }
1204
1205
1206 // Load a class from the shared spaces (found through the shared system
1207 // dictionary). Force the superclass and all interfaces to be loaded.
1208 // Update the class definition to include sibling classes and no
1209 // subclasses (yet). [Classes in the shared space are not part of the
1210 // object hierarchy until loaded.]
1211
1212 InstanceKlass* SystemDictionary::load_shared_class(
1213 Symbol* class_name, Handle class_loader, TRAPS) {
1214 InstanceKlass* ik = find_shared_class(class_name);
1215 // Make sure we only return the boot class for the NULL classloader.
1216 if (ik != NULL &&
1217 ik->is_shared_boot_class() && class_loader.is_null()) {
1218 Handle protection_domain;
1219 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1220 }
1221 return NULL;
1222 }
1223
1224 // Check if a shared class can be loaded by the specific classloader:
1225 //
1226 // NULL classloader:
1227 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1228 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1229 // be defined in an unnamed module.
1230 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1231 InstanceKlass* ik,
1232 Handle class_loader, TRAPS) {
1233 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1234 "Cannot use sharing if java.base is patched");
1235 ResourceMark rm;
1236 int path_index = ik->shared_classpath_index();
1237 SharedClassPathEntry* ent =
1238 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1239 if (!Universe::is_module_initialized()) {
1240 assert(ent != NULL && ent->is_jrt(),
1241 "Loading non-bootstrap classes before the module system is initialized");
1242 assert(class_loader.is_null(), "sanity");
1243 return true;
1244 }
1245 // Get the pkg_entry from the classloader
1246 TempNewSymbol pkg_name = NULL;
1247 PackageEntry* pkg_entry = NULL;
1248 ModuleEntry* mod_entry = NULL;
1249 const char* pkg_string = NULL;
1250 ClassLoaderData* loader_data = class_loader_data(class_loader);
1251 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1252 if (pkg_name != NULL) {
1253 pkg_string = pkg_name->as_C_string();
1254 if (loader_data != NULL) {
1255 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1256 }
1257 if (pkg_entry != NULL) {
1258 mod_entry = pkg_entry->module();
1259 }
1260 }
1261
1262 // If the archived class is from a module that has been patched at runtime,
1263 // the class cannot be loaded from the archive.
1264 if (mod_entry != NULL && mod_entry->is_patched()) {
1265 return false;
1266 }
1267
1268 if (class_loader.is_null()) {
1269 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1270 // The NULL classloader can load archived class originated from the
1271 // "modules" jimage and the -Xbootclasspath/a. For class from the
1272 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1273 // by the NULL classloader.
1274 if (mod_entry != NULL) {
1275 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1276 // ModuleEntry's location agrees with the archived class' origination.
1277 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1278 return true; // Module class from the "module" jimage
1279 }
1280 }
1281
1282 // If the archived class is not from the "module" jimage, the class can be
1283 // loaded by the NULL classloader if
1284 //
1285 // 1. the class is from the unamed package
1286 // 2. or, the class is not from a module defined in the NULL classloader
1287 // 3. or, the class is from an unamed module
1288 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1289 // the class is from the -Xbootclasspath/a
1290 if (pkg_string == NULL ||
1291 pkg_entry == NULL ||
1292 pkg_entry->in_unnamed_module()) {
1293 assert(mod_entry == NULL ||
1294 mod_entry == loader_data->unnamed_module(),
1295 "the unnamed module is not defined in the classloader");
1296 return true;
1297 }
1298 }
1299 return false;
1300 } else {
1301 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1302 ik, class_loader, pkg_string, pkg_name,
1303 pkg_entry, mod_entry, CHECK_(false));
1304 return res;
1305 }
1306 }
1307
1308 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1309 Handle class_loader,
1310 Handle protection_domain, TRAPS) {
1311
1312 if (ik != NULL) {
1313 Symbol* class_name = ik->name();
1314
1315 bool visible = is_shared_class_visible(
1316 class_name, ik, class_loader, CHECK_NULL);
1317 if (!visible) {
1318 return NULL;
1319 }
1320
1321 // Resolve the superclass and interfaces. They must be the same
1322 // as in dump time, because the layout of <ik> depends on
1323 // the specific layout of ik->super() and ik->local_interfaces().
1324 //
1325 // If unexpected superclass or interfaces are found, we cannot
1326 // load <ik> from the shared archive.
1327
1328 if (ik->super() != NULL) {
1329 Symbol* cn = ik->super()->name();
1330 Klass *s = resolve_super_or_fail(class_name, cn,
1331 class_loader, protection_domain, true, CHECK_NULL);
1332 if (s != ik->super()) {
1333 // The dynamically resolved super class is not the same as the one we used during dump time,
1334 // so we cannot use ik.
1335 return NULL;
1336 } else {
1337 assert(s->is_shared(), "must be");
1338 }
1339 }
1340
1341 Array<Klass*>* interfaces = ik->local_interfaces();
1342 int num_interfaces = interfaces->length();
1343 for (int index = 0; index < num_interfaces; index++) {
1344 Klass* k = interfaces->at(index);
1345 Symbol* name = k->name();
1346 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1347 if (k != i) {
1348 // The dynamically resolved interface class is not the same as the one we used during dump time,
1349 // so we cannot use ik.
1350 return NULL;
1351 } else {
1352 assert(i->is_shared(), "must be");
1353 }
1354 }
1355
1356 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1357 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1358 if (new_ik != NULL) {
1359 // The class is changed by CFLH. Return the new class. The shared class is
1360 // not used.
1361 return new_ik;
1362 }
1363
1364 // Adjust methods to recover missing data. They need addresses for
1365 // interpreter entry points and their default native method address
1366 // must be reset.
1367
1368 // Updating methods must be done under a lock so multiple
1369 // threads don't update these in parallel
1370 //
1371 // Shared classes are all currently loaded by either the bootstrap or
1372 // internal parallel class loaders, so this will never cause a deadlock
1373 // on a custom class loader lock.
1374
1375 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1376 {
1377 HandleMark hm(THREAD);
1378 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1379 check_loader_lock_contention(lockObject, THREAD);
1380 ObjectLocker ol(lockObject, THREAD, true);
1381 // prohibited package check assumes all classes loaded from archive call
1382 // restore_unshareable_info which calls ik->set_package()
1383 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1384 }
1385
1386 ik->print_class_load_logging(loader_data, NULL, NULL);
1387
1388 // For boot loader, ensure that GetSystemPackage knows that a class in this
1389 // package was loaded.
1390 if (class_loader.is_null()) {
1391 int path_index = ik->shared_classpath_index();
1392 ResourceMark rm;
1393 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1394 }
1395
1396 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1397 // Only dump the classes that can be stored into CDS archive
1398 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1399 ResourceMark rm(THREAD);
1400 classlist_file->print_cr("%s", ik->name()->as_C_string());
1401 classlist_file->flush();
1402 }
1403 }
1404
1405 // notify a class loaded from shared object
1406 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1407 }
1408
1409 ik->set_has_passed_fingerprint_check(false);
1410 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1411 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1412 uint64_t cds_fp = ik->get_stored_fingerprint();
1413 if (aot_fp != 0 && aot_fp == cds_fp) {
1414 // This class matches with a class saved in an AOT library
1415 ik->set_has_passed_fingerprint_check(true);
1416 } else {
1417 ResourceMark rm;
1418 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1419 }
1420 }
1421 return ik;
1422 }
1423 #endif // INCLUDE_CDS
1424
1425 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1426
1427 if (class_loader.is_null()) {
1428 ResourceMark rm;
1429 PackageEntry* pkg_entry = NULL;
1430 bool search_only_bootloader_append = false;
1431 ClassLoaderData *loader_data = class_loader_data(class_loader);
1432
1433 // Find the package in the boot loader's package entry table.
1434 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1435 if (pkg_name != NULL) {
1436 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1437 }
1438
1439 // Prior to attempting to load the class, enforce the boot loader's
1440 // visibility boundaries.
1441 if (!Universe::is_module_initialized()) {
1442 // During bootstrapping, prior to module initialization, any
1443 // class attempting to be loaded must be checked against the
1444 // java.base packages in the boot loader's PackageEntryTable.
1445 // No class outside of java.base is allowed to be loaded during
1446 // this bootstrapping window.
1447 if (!DumpSharedSpaces) {
1448 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1449 // Class is either in the unnamed package or in
1450 // a named package within the unnamed module. Either
1451 // case is outside of java.base, do not attempt to
1452 // load the class post java.base definition. If
1453 // java.base has not been defined, let the class load
1454 // and its package will be checked later by
1455 // ModuleEntryTable::verify_javabase_packages.
1456 if (ModuleEntryTable::javabase_defined()) {
1457 return NULL;
1458 }
1459 } else {
1460 // Check that the class' package is defined within java.base.
1461 ModuleEntry* mod_entry = pkg_entry->module();
1462 Symbol* mod_entry_name = mod_entry->name();
1463 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1464 return NULL;
1465 }
1466 }
1467 }
1468 } else {
1469 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1470 // After the module system has been initialized, check if the class'
1471 // package is in a module defined to the boot loader.
1472 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1473 // Class is either in the unnamed package, in a named package
1474 // within a module not defined to the boot loader or in a
1475 // a named package within the unnamed module. In all cases,
1476 // limit visibility to search for the class only in the boot
1477 // loader's append path.
1478 search_only_bootloader_append = true;
1479 }
1480 }
1481
1482 // Prior to bootstrapping's module initialization, never load a class outside
1483 // of the boot loader's module path
1484 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1485 !search_only_bootloader_append,
1486 "Attempt to load a class outside of boot loader's module path");
1487
1488 // Search the shared system dictionary for classes preloaded into the
1489 // shared spaces.
1490 InstanceKlass* k = NULL;
1491 {
1492 #if INCLUDE_CDS
1493 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1494 k = load_shared_class(class_name, class_loader, THREAD);
1495 #endif
1496 }
1497
1498 if (k == NULL) {
1499 // Use VM class loader
1500 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1501 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1502 }
1503
1504 // find_or_define_instance_class may return a different InstanceKlass
1505 if (k != NULL) {
1506 InstanceKlass* defined_k =
1507 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1508 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1509 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1510 assert(defined_k != NULL, "Should have a klass if there's no exception");
1511 loader_data->add_to_deallocate_list(k);
1512 k = defined_k;
1513 } else if (HAS_PENDING_EXCEPTION) {
1514 loader_data->add_to_deallocate_list(k);
1515 return NULL;
1516 }
1517 }
1518 return k;
1519 } else {
1520 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1521 ResourceMark rm(THREAD);
1522
1523 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1524 JavaThread* jt = (JavaThread*) THREAD;
1525
1526 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1527 ClassLoader::perf_app_classload_selftime(),
1528 ClassLoader::perf_app_classload_count(),
1529 jt->get_thread_stat()->perf_recursion_counts_addr(),
1530 jt->get_thread_stat()->perf_timers_addr(),
1531 PerfClassTraceTime::CLASS_LOAD);
1532
1533 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1534 // Translate to external class name format, i.e., convert '/' chars to '.'
1535 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1536
1537 JavaValue result(T_OBJECT);
1538
1539 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1540
1541 // Call public unsynchronized loadClass(String) directly for all class loaders
1542 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1543 // acquire a class-name based lock rather than the class loader object lock.
1544 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1545 // so the call to loadClassInternal() was not required.
1546 //
1547 // UnsyncloadClass flag means both call loadClass(String) and do
1548 // not acquire the class loader lock even for class loaders that are
1549 // not parallelCapable. This was a risky transitional
1550 // flag for diagnostic purposes only. It is risky to call
1551 // custom class loaders without synchronization.
1552 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1553 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1554 // Do NOT assume this will be supported in future releases.
1555 //
1556 // Added MustCallLoadClassInternal in case we discover in the field
1557 // a customer that counts on this call
1558 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1559 JavaCalls::call_special(&result,
1560 class_loader,
1561 spec_klass,
1562 vmSymbols::loadClassInternal_name(),
1563 vmSymbols::string_class_signature(),
1564 string,
1565 CHECK_NULL);
1566 } else {
1567 JavaCalls::call_virtual(&result,
1568 class_loader,
1569 spec_klass,
1570 vmSymbols::loadClass_name(),
1571 vmSymbols::string_class_signature(),
1572 string,
1573 CHECK_NULL);
1574 }
1575
1576 assert(result.get_type() == T_OBJECT, "just checking");
1577 oop obj = (oop) result.get_jobject();
1578
1579 // Primitive classes return null since forName() can not be
1580 // used to obtain any of the Class objects representing primitives or void
1581 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1582 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1583 // For user defined Java class loaders, check that the name returned is
1584 // the same as that requested. This check is done for the bootstrap
1585 // loader when parsing the class file.
1586 if (class_name == k->name()) {
1587 return k;
1588 }
1589 }
1590 // Class is not found or has the wrong name, return NULL
1591 return NULL;
1592 }
1593 }
1594
1595 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1596
1597 HandleMark hm(THREAD);
1598 ClassLoaderData* loader_data = k->class_loader_data();
1599 Handle class_loader_h(THREAD, loader_data->class_loader());
1600
1601 // for bootstrap and other parallel classloaders don't acquire lock,
1602 // use placeholder token
1603 // If a parallelCapable class loader calls define_instance_class instead of
1604 // find_or_define_instance_class to get here, we have a timing
1605 // hole with systemDictionary updates and check_constraints
1606 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1607 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1608 compute_loader_lock_object(class_loader_h, THREAD)),
1609 "define called without lock");
1610 }
1611
1612 // Check class-loading constraints. Throw exception if violation is detected.
1613 // Grabs and releases SystemDictionary_lock
1614 // The check_constraints/find_class call and update_dictionary sequence
1615 // must be "atomic" for a specific class/classloader pair so we never
1616 // define two different instanceKlasses for that class/classloader pair.
1617 // Existing classloaders will call define_instance_class with the
1618 // classloader lock held
1619 // Parallel classloaders will call find_or_define_instance_class
1620 // which will require a token to perform the define class
1621 Symbol* name_h = k->name();
1622 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1623 int d_index = dictionary()->hash_to_index(d_hash);
1624 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1625
1626 // Register class just loaded with class loader (placed in Vector)
1627 // Note we do this before updating the dictionary, as this can
1628 // fail with an OutOfMemoryError (if it does, we will *not* put this
1629 // class in the dictionary and will not update the class hierarchy).
1630 // JVMTI FollowReferences needs to find the classes this way.
1631 if (k->class_loader() != NULL) {
1632 methodHandle m(THREAD, Universe::loader_addClass_method());
1633 JavaValue result(T_VOID);
1634 JavaCallArguments args(class_loader_h);
1635 args.push_oop(Handle(THREAD, k->java_mirror()));
1636 JavaCalls::call(&result, m, &args, CHECK);
1637 }
1638
1639 // Add the new class. We need recompile lock during update of CHA.
1640 {
1641 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1642 int p_index = placeholders()->hash_to_index(p_hash);
1643
1644 MutexLocker mu_r(Compile_lock, THREAD);
1645
1646 // Add to class hierarchy, initialize vtables, and do possible
1647 // deoptimizations.
1648 add_to_hierarchy(k, CHECK); // No exception, but can block
1649
1650 // Add to systemDictionary - so other classes can see it.
1651 // Grabs and releases SystemDictionary_lock
1652 update_dictionary(d_index, d_hash, p_index, p_hash,
1653 k, class_loader_h, THREAD);
1654 }
1655 k->eager_initialize(THREAD);
1656
1657 // notify jvmti
1658 if (JvmtiExport::should_post_class_load()) {
1659 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1660 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1661
1662 }
1663 TRACE_ONLY(post_class_define_event(k, loader_data);)
1664 }
1665
1666 // Support parallel classloading
1667 // All parallel class loaders, including bootstrap classloader
1668 // lock a placeholder entry for this class/class_loader pair
1669 // to allow parallel defines of different classes for this class loader
1670 // With AllowParallelDefine flag==true, in case they do not synchronize around
1671 // FindLoadedClass/DefineClass, calls, we check for parallel
1672 // loading for them, wait if a defineClass is in progress
1673 // and return the initial requestor's results
1674 // This flag does not apply to the bootstrap classloader.
1675 // With AllowParallelDefine flag==false, call through to define_instance_class
1676 // which will throw LinkageError: duplicate class definition.
1677 // False is the requested default.
1678 // For better performance, the class loaders should synchronize
1679 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1680 // potentially waste time reading and parsing the bytestream.
1681 // Note: VM callers should ensure consistency of k/class_name,class_loader
1682 // Be careful when modifying this code: once you have run
1683 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1684 // you need to find_and_remove it before returning.
1685 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1686 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1687 InstanceKlass* k, TRAPS) {
1688
1689 Symbol* name_h = k->name(); // passed in class_name may be null
1690 ClassLoaderData* loader_data = class_loader_data(class_loader);
1691
1692 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1693 int d_index = dictionary()->hash_to_index(d_hash);
1694
1695 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1696 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1697 int p_index = placeholders()->hash_to_index(p_hash);
1698 PlaceholderEntry* probe;
1699
1700 {
1701 MutexLocker mu(SystemDictionary_lock, THREAD);
1702 // First check if class already defined
1703 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1704 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1705 if (check != NULL) {
1706 return check;
1707 }
1708 }
1709
1710 // Acquire define token for this class/classloader
1711 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1712 // Wait if another thread defining in parallel
1713 // All threads wait - even those that will throw duplicate class: otherwise
1714 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1715 // if other thread has not finished updating dictionary
1716 while (probe->definer() != NULL) {
1717 SystemDictionary_lock->wait();
1718 }
1719 // Only special cases allow parallel defines and can use other thread's results
1720 // Other cases fall through, and may run into duplicate defines
1721 // caught by finding an entry in the SystemDictionary
1722 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1723 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1724 SystemDictionary_lock->notify_all();
1725 #ifdef ASSERT
1726 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1727 assert(check != NULL, "definer missed recording success");
1728 #endif
1729 return probe->instance_klass();
1730 } else {
1731 // This thread will define the class (even if earlier thread tried and had an error)
1732 probe->set_definer(THREAD);
1733 }
1734 }
1735
1736 define_instance_class(k, THREAD);
1737
1738 Handle linkage_exception = Handle(); // null handle
1739
1740 // definer must notify any waiting threads
1741 {
1742 MutexLocker mu(SystemDictionary_lock, THREAD);
1743 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1744 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1745 if (probe != NULL) {
1746 if (HAS_PENDING_EXCEPTION) {
1747 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1748 CLEAR_PENDING_EXCEPTION;
1749 } else {
1750 probe->set_instance_klass(k);
1751 }
1752 probe->set_definer(NULL);
1753 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1754 SystemDictionary_lock->notify_all();
1755 }
1756 }
1757
1758 // Can't throw exception while holding lock due to rank ordering
1759 if (linkage_exception() != NULL) {
1760 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1761 }
1762
1763 return k;
1764 }
1765 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1766 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1767 if (class_loader.is_null()) {
1768 return Handle(THREAD, _system_loader_lock_obj);
1769 } else {
1770 return class_loader;
1771 }
1772 }
1773
1774 // This method is added to check how often we have to wait to grab loader
1775 // lock. The results are being recorded in the performance counters defined in
1776 // ClassLoader::_sync_systemLoaderLockContentionRate and
1777 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1778 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1779 if (!UsePerfData) {
1780 return;
1781 }
1782
1783 assert(!loader_lock.is_null(), "NULL lock object");
1784
1785 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1786 == ObjectSynchronizer::owner_other) {
1787 // contention will likely happen, so increment the corresponding
1788 // contention counter.
1789 if (loader_lock() == _system_loader_lock_obj) {
1790 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1791 } else {
1792 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1793 }
1794 }
1795 }
1796
1797 // ----------------------------------------------------------------------------
1798 // Lookup
1799
1800 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1801 Symbol* class_name,
1802 ClassLoaderData* loader_data) {
1803 assert_locked_or_safepoint(SystemDictionary_lock);
1804 assert (index == dictionary()->index_for(class_name, loader_data),
1805 "incorrect index?");
1806
1807 return dictionary()->find_class(index, hash, class_name, loader_data);
1808 }
1809
1810
1811 // Basic find on classes in the midst of being loaded
1812 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1813 ClassLoaderData* loader_data) {
1814 assert_locked_or_safepoint(SystemDictionary_lock);
1815 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1816 int p_index = placeholders()->hash_to_index(p_hash);
1817 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1818 }
1819
1820
1821 // Used for assertions and verification only
1822 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1823 #ifndef ASSERT
1824 guarantee(VerifyBeforeGC ||
1825 VerifyDuringGC ||
1826 VerifyBeforeExit ||
1827 VerifyDuringStartup ||
1828 VerifyAfterGC, "too expensive");
1829 #endif
1830 assert_locked_or_safepoint(SystemDictionary_lock);
1831
1832 // First look in the loaded class array
1833 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1834 int d_index = dictionary()->hash_to_index(d_hash);
1835 return find_class(d_index, d_hash, class_name, loader_data);
1836 }
1837
1838
1839 // Get the next class in the dictionary.
1840 Klass* SystemDictionary::try_get_next_class() {
1841 return dictionary()->try_get_next_class();
1842 }
1843
1844
1845 // ----------------------------------------------------------------------------
1846 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1847 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1848 // before a new class is used.
1849
1850 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1851 assert(k != NULL, "just checking");
1852 assert_locked_or_safepoint(Compile_lock);
1853
1854 // Link into hierachy. Make sure the vtables are initialized before linking into
1855 k->append_to_sibling_list(); // add to superklass/sibling list
1856 k->process_interfaces(THREAD); // handle all "implements" declarations
1857 k->set_init_state(InstanceKlass::loaded);
1858 // Now flush all code that depended on old class hierarchy.
1859 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1860 // Also, first reinitialize vtable because it may have gotten out of synch
1861 // while the new class wasn't connected to the class hierarchy.
1862 CodeCache::flush_dependents_on(k);
1863 }
1864
1865 // ----------------------------------------------------------------------------
1866 // GC support
1867
1868 // Following roots during mark-sweep is separated in two phases.
1869 //
1870 // The first phase follows preloaded classes and all other system
1871 // classes, since these will never get unloaded anyway.
1872 //
1873 // The second phase removes (unloads) unreachable classes from the
1874 // system dictionary and follows the remaining classes' contents.
1875
1876 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1877 roots_oops_do(blk, NULL);
1878 }
1879
1880 // Calculate a "good" systemdictionary size based
1881 // on predicted or current loaded classes count
1882 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1883 int newsize = _old_default_sdsize;
1884 if ((classcount > 0) && !DumpSharedSpaces) {
1885 int desiredsize = classcount/_average_depth_goal;
1886 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1887 newsize = _primelist[++_sdgeneration]) {
1888 if (desiredsize <= newsize) {
1889 break;
1890 }
1891 }
1892 }
1893 return newsize;
1894 }
1895
1896 #ifdef ASSERT
1897 class VerifySDReachableAndLiveClosure : public OopClosure {
1898 private:
1899 BoolObjectClosure* _is_alive;
1900
1901 template <class T> void do_oop_work(T* p) {
1902 oop obj = oopDesc::load_decode_heap_oop(p);
1903 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1904 }
1905
1906 public:
1907 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1908
1909 virtual void do_oop(oop* p) { do_oop_work(p); }
1910 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1911 };
1912 #endif
1913
1914 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1915 // Note: anonymous classes are not in the SD.
1916 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1917 GCTimer* gc_timer,
1918 bool do_cleaning) {
1919
1920
1921 bool unloading_occurred;
1922 {
1923 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1924
1925 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1926 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1927 do_cleaning);
1928 }
1929
1930 if (unloading_occurred) {
1931 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1932 dictionary()->do_unloading();
1933 constraints()->purge_loader_constraints();
1934 resolution_errors()->purge_resolution_errors();
1935 }
1936
1937 {
1938 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1939 // Oops referenced by the system dictionary may get unreachable independently
1940 // of the class loader (eg. cached protection domain oops). So we need to
1941 // explicitly unlink them here instead of in Dictionary::do_unloading.
1942 dictionary()->unlink(is_alive);
1943 #ifdef ASSERT
1944 VerifySDReachableAndLiveClosure cl(is_alive);
1945 dictionary()->oops_do(&cl);
1946 #endif
1947 }
1948
1949 if (do_cleaning) {
1950 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1951 ResolvedMethodTable::unlink(is_alive);
1952 }
1953
1954 return unloading_occurred;
1955 }
1956
1957 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1958 strong->do_oop(&_java_system_loader);
1959 strong->do_oop(&_system_loader_lock_obj);
1960 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1961
1962 // Adjust dictionary
1963 dictionary()->roots_oops_do(strong, weak);
1964
1965 // Visit extra methods
1966 invoke_method_table()->oops_do(strong);
1967
1968 if (weak != NULL) {
1969 ResolvedMethodTable::oops_do(weak);
1970 }
1971 }
1972
1973 void SystemDictionary::oops_do(OopClosure* f) {
1974 f->do_oop(&_java_system_loader);
1975 f->do_oop(&_system_loader_lock_obj);
1976 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1977
1978 // Adjust dictionary
1979 dictionary()->oops_do(f);
1980
1981 // Visit extra methods
1982 invoke_method_table()->oops_do(f);
1983
1984 ResolvedMethodTable::oops_do(f);
1985 }
1986
1987 // Just the classes from defining class loaders
1988 // Don't iterate over placeholders
1989 void SystemDictionary::classes_do(void f(Klass*)) {
1990 dictionary()->classes_do(f);
1991 }
1992
1993 // Added for initialize_itable_for_klass
1994 // Just the classes from defining class loaders
1995 // Don't iterate over placeholders
1996 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1997 dictionary()->classes_do(f, CHECK);
1998 }
1999
2000 // All classes, and their class loaders
2001 // Don't iterate over placeholders
2002 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
2003 dictionary()->classes_do(f);
2004 }
2005
2006 void SystemDictionary::methods_do(void f(Method*)) {
2007 // Walk methods in loaded classes
2008 ClassLoaderDataGraph::methods_do(f);
2009 // Walk method handle intrinsics
2010 invoke_method_table()->methods_do(f);
2011 }
2012
2013 void SystemDictionary::remove_classes_in_error_state() {
2014 dictionary()->remove_classes_in_error_state();
2015 }
2016
2017 // ----------------------------------------------------------------------------
2018 // Lazily load klasses
2019
2020 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2021 // if multiple threads calling this function, only one thread will load
2022 // the class. The other threads will find the loaded version once the
2023 // class is loaded.
2024 Klass* aos = _abstract_ownable_synchronizer_klass;
2025 if (aos == NULL) {
2026 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2027 // Force a fence to prevent any read before the write completes
2028 OrderAccess::fence();
2029 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2030 }
2031 }
2032
2033 // ----------------------------------------------------------------------------
2034 // Initialization
2035
2036 void SystemDictionary::initialize(TRAPS) {
2037 // Allocate arrays
2038 assert(dictionary() == NULL,
2039 "SystemDictionary should only be initialized once");
2040 _sdgeneration = 0;
2041 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2042 _placeholders = new PlaceholderTable(_nof_buckets);
2043 _number_of_modifications = 0;
2044 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2045 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2046 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2047
2048 // Allocate private object used as system class loader lock
2049 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2050 // Initialize basic classes
2051 initialize_preloaded_classes(CHECK);
2052 }
2053
2054 // Compact table of directions on the initialization of klasses:
2055 static const short wk_init_info[] = {
2056 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2057 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2058 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2059 | (int)SystemDictionary::option ),
2060 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2061 #undef WK_KLASS_INIT_INFO
2062 0
2063 };
2064
2065 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2066 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2067 int info = wk_init_info[id - FIRST_WKID];
2068 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2069 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2070 InstanceKlass** klassp = &_well_known_klasses[id];
2071
2072 bool must_load;
2073 #if INCLUDE_JVMCI
2074 if (EnableJVMCI) {
2075 // If JVMCI is enabled we require its classes to be found.
2076 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2077 } else
2078 #endif
2079 {
2080 must_load = (init_opt < SystemDictionary::Opt);
2081 }
2082
2083 if ((*klassp) == NULL) {
2084 Klass* k;
2085 if (must_load) {
2086 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2087 } else {
2088 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2089 }
2090 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2091 }
2092 return ((*klassp) != NULL);
2093 }
2094
2095 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2096 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2097 for (int id = (int)start_id; id < (int)limit_id; id++) {
2098 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2099 int info = wk_init_info[id - FIRST_WKID];
2100 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2101 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2102
2103 initialize_wk_klass((WKID)id, opt, CHECK);
2104 }
2105
2106 // move the starting value forward to the limit:
2107 start_id = limit_id;
2108 }
2109
2110 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2111 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2112
2113 // Create the ModuleEntry for java.base. This call needs to be done here,
2114 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2115 ClassLoader::classLoader_init2(CHECK);
2116
2117 // Preload commonly used klasses
2118 WKID scan = FIRST_WKID;
2119 // first do Object, then String, Class
2120 if (UseSharedSpaces) {
2121 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2122 // Initialize the constant pool for the Object_class
2123 Object_klass()->constants()->restore_unshareable_info(CHECK);
2124 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2125 } else {
2126 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2127 }
2128
2129 // Calculate offsets for String and Class classes since they are loaded and
2130 // can be used after this point.
2131 java_lang_String::compute_offsets();
2132 java_lang_Class::compute_offsets();
2133
2134 // Fixup mirrors for classes loaded before java.lang.Class.
2135 // These calls iterate over the objects currently in the perm gen
2136 // so calling them at this point is matters (not before when there
2137 // are fewer objects and not later after there are more objects
2138 // in the perm gen.
2139 Universe::initialize_basic_type_mirrors(CHECK);
2140 Universe::fixup_mirrors(CHECK);
2141
2142 // do a bunch more:
2143 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2144
2145 // Preload ref klasses and set reference types
2146 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2147 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2148
2149 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2150 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2151 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2152 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2153 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2154
2155 // JSR 292 classes
2156 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2157 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2158 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2159 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2160 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2161
2162 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2163 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2164 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2165 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2166 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2167 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2168 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2169 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2170 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2171 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2172
2173 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2174 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2175 _has_loadClassInternal = (method != NULL);
2176 }
2177 { // Compute whether we should use checkPackageAccess or NOT
2178 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2179 _has_checkPackageAccess = (method != NULL);
2180 }
2181 }
2182
2183 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2184 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2185 BasicType SystemDictionary::box_klass_type(Klass* k) {
2186 assert(k != NULL, "");
2187 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2188 if (_box_klasses[i] == k)
2189 return (BasicType)i;
2190 }
2191 return T_OBJECT;
2192 }
2193
2194 // Constraints on class loaders. The details of the algorithm can be
2195 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2196 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2197 // that the system dictionary needs to maintain a set of contraints that
2198 // must be satisfied by all classes in the dictionary.
2199 // if defining is true, then LinkageError if already in systemDictionary
2200 // if initiating loader, then ok if InstanceKlass matches existing entry
2201
2202 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2203 InstanceKlass* k,
2204 Handle class_loader, bool defining,
2205 TRAPS) {
2206 const char *linkage_error1 = NULL;
2207 const char *linkage_error2 = NULL;
2208 {
2209 Symbol* name = k->name();
2210 ClassLoaderData *loader_data = class_loader_data(class_loader);
2211
2212 MutexLocker mu(SystemDictionary_lock, THREAD);
2213
2214 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
2215 if (check != NULL) {
2216 // if different InstanceKlass - duplicate class definition,
2217 // else - ok, class loaded by a different thread in parallel,
2218 // we should only have found it if it was done loading and ok to use
2219 // system dictionary only holds instance classes, placeholders
2220 // also holds array classes
2221
2222 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2223 if ((defining == true) || (k != check)) {
2224 linkage_error1 = "loader (instance of ";
2225 linkage_error2 = "): attempted duplicate class definition for name: \"";
2226 } else {
2227 return;
2228 }
2229 }
2230
2231 #ifdef ASSERT
2232 Symbol* ph_check = find_placeholder(name, loader_data);
2233 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2234 #endif
2235
2236 if (linkage_error1 == NULL) {
2237 if (constraints()->check_or_update(k, class_loader, name) == false) {
2238 linkage_error1 = "loader constraint violation: loader (instance of ";
2239 linkage_error2 = ") previously initiated loading for a different type with name \"";
2240 }
2241 }
2242 }
2243
2244 // Throw error now if needed (cannot throw while holding
2245 // SystemDictionary_lock because of rank ordering)
2246
2247 if (linkage_error1) {
2248 ResourceMark rm(THREAD);
2249 const char* class_loader_name = loader_name(class_loader());
2250 char* type_name = k->name()->as_C_string();
2251 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2252 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2253 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2254 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2255 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2256 }
2257 }
2258
2259
2260 // Update system dictionary - done after check_constraint and add_to_hierachy
2261 // have been called.
2262 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2263 int p_index, unsigned int p_hash,
2264 InstanceKlass* k,
2265 Handle class_loader,
2266 TRAPS) {
2267 // Compile_lock prevents systemDictionary updates during compilations
2268 assert_locked_or_safepoint(Compile_lock);
2269 Symbol* name = k->name();
2270 ClassLoaderData *loader_data = class_loader_data(class_loader);
2271
2272 {
2273 MutexLocker mu1(SystemDictionary_lock, THREAD);
2274
2275 // See whether biased locking is enabled and if so set it for this
2276 // klass.
2277 // Note that this must be done past the last potential blocking
2278 // point / safepoint. We enable biased locking lazily using a
2279 // VM_Operation to iterate the SystemDictionary and installing the
2280 // biasable mark word into each InstanceKlass's prototype header.
2281 // To avoid race conditions where we accidentally miss enabling the
2282 // optimization for one class in the process of being added to the
2283 // dictionary, we must not safepoint after the test of
2284 // BiasedLocking::enabled().
2285 if (UseBiasedLocking && BiasedLocking::enabled()) {
2286 // Set biased locking bit for all loaded classes; it will be
2287 // cleared if revocation occurs too often for this type
2288 // NOTE that we must only do this when the class is initally
2289 // defined, not each time it is referenced from a new class loader
2290 if (k->class_loader() == class_loader()) {
2291 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2292 }
2293 }
2294
2295 // Make a new system dictionary entry.
2296 InstanceKlass* sd_check = find_class(d_index, d_hash, name, loader_data);
2297 if (sd_check == NULL) {
2298 dictionary()->add_klass(name, loader_data, k);
2299 notice_modification();
2300 }
2301 #ifdef ASSERT
2302 sd_check = find_class(d_index, d_hash, name, loader_data);
2303 assert (sd_check != NULL, "should have entry in system dictionary");
2304 // Note: there may be a placeholder entry: for circularity testing
2305 // or for parallel defines
2306 #endif
2307 SystemDictionary_lock->notify_all();
2308 }
2309 }
2310
2311
2312 // Try to find a class name using the loader constraints. The
2313 // loader constraints might know about a class that isn't fully loaded
2314 // yet and these will be ignored.
2315 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2316 Symbol* class_name, Handle class_loader, TRAPS) {
2317
2318 // First see if it has been loaded directly.
2319 // Force the protection domain to be null. (This removes protection checks.)
2320 Handle no_protection_domain;
2321 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2322 no_protection_domain, CHECK_NULL);
2323 if (klass != NULL)
2324 return klass;
2325
2326 // Now look to see if it has been loaded elsewhere, and is subject to
2327 // a loader constraint that would require this loader to return the
2328 // klass that is already loaded.
2329 if (FieldType::is_array(class_name)) {
2330 // For array classes, their Klass*s are not kept in the
2331 // constraint table. The element Klass*s are.
2332 FieldArrayInfo fd;
2333 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2334 if (t != T_OBJECT) {
2335 klass = Universe::typeArrayKlassObj(t);
2336 } else {
2337 MutexLocker mu(SystemDictionary_lock, THREAD);
2338 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2339 }
2340 // If element class already loaded, allocate array klass
2341 if (klass != NULL) {
2342 klass = klass->array_klass_or_null(fd.dimension());
2343 }
2344 } else {
2345 MutexLocker mu(SystemDictionary_lock, THREAD);
2346 // Non-array classes are easy: simply check the constraint table.
2347 klass = constraints()->find_constrained_klass(class_name, class_loader);
2348 }
2349
2350 return klass;
2351 }
2352
2353
2354 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2355 Handle class_loader1,
2356 Handle class_loader2,
2357 Thread* THREAD) {
2358 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2359 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2360
2361 Symbol* constraint_name = NULL;
2362 if (!FieldType::is_array(class_name)) {
2363 constraint_name = class_name;
2364 } else {
2365 // For array classes, their Klass*s are not kept in the
2366 // constraint table. The element classes are.
2367 FieldArrayInfo fd;
2368 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2369 // primitive types always pass
2370 if (t != T_OBJECT) {
2371 return true;
2372 } else {
2373 constraint_name = fd.object_key();
2374 }
2375 }
2376 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2377 int d_index1 = dictionary()->hash_to_index(d_hash1);
2378
2379 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2380 int d_index2 = dictionary()->hash_to_index(d_hash2);
2381 {
2382 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2383
2384 // Better never do a GC while we're holding these oops
2385 NoSafepointVerifier nosafepoint;
2386
2387 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2388 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2389 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2390 klass2, class_loader2);
2391 }
2392 }
2393
2394 // Add entry to resolution error table to record the error when the first
2395 // attempt to resolve a reference to a class has failed.
2396 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2397 Symbol* error, Symbol* message) {
2398 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2399 int index = resolution_errors()->hash_to_index(hash);
2400 {
2401 MutexLocker ml(SystemDictionary_lock, Thread::current());
2402 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2403 }
2404 }
2405
2406 // Delete a resolution error for RedefineClasses for a constant pool is going away
2407 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2408 resolution_errors()->delete_entry(pool);
2409 }
2410
2411 // Lookup resolution error table. Returns error if found, otherwise NULL.
2412 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2413 Symbol** message) {
2414 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2415 int index = resolution_errors()->hash_to_index(hash);
2416 {
2417 MutexLocker ml(SystemDictionary_lock, Thread::current());
2418 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2419 if (entry != NULL) {
2420 *message = entry->message();
2421 return entry->error();
2422 } else {
2423 return NULL;
2424 }
2425 }
2426 }
2427
2428
2429 // Signature constraints ensure that callers and callees agree about
2430 // the meaning of type names in their signatures. This routine is the
2431 // intake for constraints. It collects them from several places:
2432 //
2433 // * LinkResolver::resolve_method (if check_access is true) requires
2434 // that the resolving class (the caller) and the defining class of
2435 // the resolved method (the callee) agree on each type in the
2436 // method's signature.
2437 //
2438 // * LinkResolver::resolve_interface_method performs exactly the same
2439 // checks.
2440 //
2441 // * LinkResolver::resolve_field requires that the constant pool
2442 // attempting to link to a field agree with the field's defining
2443 // class about the type of the field signature.
2444 //
2445 // * klassVtable::initialize_vtable requires that, when a class
2446 // overrides a vtable entry allocated by a superclass, that the
2447 // overriding method (i.e., the callee) agree with the superclass
2448 // on each type in the method's signature.
2449 //
2450 // * klassItable::initialize_itable requires that, when a class fills
2451 // in its itables, for each non-abstract method installed in an
2452 // itable, the method (i.e., the callee) agree with the interface
2453 // on each type in the method's signature.
2454 //
2455 // All those methods have a boolean (check_access, checkconstraints)
2456 // which turns off the checks. This is used from specialized contexts
2457 // such as bootstrapping, dumping, and debugging.
2458 //
2459 // No direct constraint is placed between the class and its
2460 // supertypes. Constraints are only placed along linked relations
2461 // between callers and callees. When a method overrides or implements
2462 // an abstract method in a supertype (superclass or interface), the
2463 // constraints are placed as if the supertype were the caller to the
2464 // overriding method. (This works well, since callers to the
2465 // supertype have already established agreement between themselves and
2466 // the supertype.) As a result of all this, a class can disagree with
2467 // its supertype about the meaning of a type name, as long as that
2468 // class neither calls a relevant method of the supertype, nor is
2469 // called (perhaps via an override) from the supertype.
2470 //
2471 //
2472 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2473 //
2474 // Make sure all class components (including arrays) in the given
2475 // signature will be resolved to the same class in both loaders.
2476 // Returns the name of the type that failed a loader constraint check, or
2477 // NULL if no constraint failed. No exception except OOME is thrown.
2478 // Arrays are not added to the loader constraint table, their elements are.
2479 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2480 Handle loader1, Handle loader2,
2481 bool is_method, TRAPS) {
2482 // Nothing to do if loaders are the same.
2483 if (loader1() == loader2()) {
2484 return NULL;
2485 }
2486
2487 SignatureStream sig_strm(signature, is_method);
2488 while (!sig_strm.is_done()) {
2489 if (sig_strm.is_object()) {
2490 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2491 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2492 return sig;
2493 }
2494 }
2495 sig_strm.next();
2496 }
2497 return NULL;
2498 }
2499
2500
2501 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2502 Symbol* signature,
2503 TRAPS) {
2504 methodHandle empty;
2505 assert(MethodHandles::is_signature_polymorphic(iid) &&
2506 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2507 iid != vmIntrinsics::_invokeGeneric,
2508 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2509
2510 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2511 int index = invoke_method_table()->hash_to_index(hash);
2512 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2513 methodHandle m;
2514 if (spe == NULL || spe->method() == NULL) {
2515 spe = NULL;
2516 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2517 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2518 if (!Arguments::is_interpreter_only()) {
2519 // Generate a compiled form of the MH intrinsic.
2520 AdapterHandlerLibrary::create_native_wrapper(m);
2521 // Check if have the compiled code.
2522 if (!m->has_compiled_code()) {
2523 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2524 "Out of space in CodeCache for method handle intrinsic", empty);
2525 }
2526 }
2527 // Now grab the lock. We might have to throw away the new method,
2528 // if a racing thread has managed to install one at the same time.
2529 {
2530 MutexLocker ml(SystemDictionary_lock, THREAD);
2531 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2532 if (spe == NULL)
2533 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2534 if (spe->method() == NULL)
2535 spe->set_method(m());
2536 }
2537 }
2538
2539 assert(spe != NULL && spe->method() != NULL, "");
2540 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2541 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2542 "MH intrinsic invariant");
2543 return spe->method();
2544 }
2545
2546 // Helper for unpacking the return value from linkMethod and linkCallSite.
2547 static methodHandle unpack_method_and_appendix(Handle mname,
2548 Klass* accessing_klass,
2549 objArrayHandle appendix_box,
2550 Handle* appendix_result,
2551 TRAPS) {
2552 methodHandle empty;
2553 if (mname.not_null()) {
2554 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2555 if (m != NULL) {
2556 oop appendix = appendix_box->obj_at(0);
2557 if (TraceMethodHandles) {
2558 #ifndef PRODUCT
2559 ttyLocker ttyl;
2560 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2561 m->print();
2562 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2563 tty->cr();
2564 #endif //PRODUCT
2565 }
2566 (*appendix_result) = Handle(THREAD, appendix);
2567 // the target is stored in the cpCache and if a reference to this
2568 // MethodName is dropped we need a way to make sure the
2569 // class_loader containing this method is kept alive.
2570 // FIXME: the appendix might also preserve this dependency.
2571 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2572 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2573 return methodHandle(THREAD, m);
2574 }
2575 }
2576 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2577 return empty;
2578 }
2579
2580 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2581 Symbol* name,
2582 Symbol* signature,
2583 Klass* accessing_klass,
2584 Handle *appendix_result,
2585 Handle *method_type_result,
2586 TRAPS) {
2587 methodHandle empty;
2588 assert(THREAD->can_call_java() ,"");
2589 Handle method_type =
2590 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2591
2592 int ref_kind = JVM_REF_invokeVirtual;
2593 oop name_oop = StringTable::intern(name, CHECK_(empty));
2594 Handle name_str (THREAD, name_oop);
2595 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2596 assert(appendix_box->obj_at(0) == NULL, "");
2597
2598 // This should not happen. JDK code should take care of that.
2599 if (accessing_klass == NULL || method_type.is_null()) {
2600 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2601 }
2602
2603 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2604 JavaCallArguments args;
2605 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2606 args.push_int(ref_kind);
2607 args.push_oop(Handle(THREAD, klass->java_mirror()));
2608 args.push_oop(name_str);
2609 args.push_oop(method_type);
2610 args.push_oop(appendix_box);
2611 JavaValue result(T_OBJECT);
2612 JavaCalls::call_static(&result,
2613 SystemDictionary::MethodHandleNatives_klass(),
2614 vmSymbols::linkMethod_name(),
2615 vmSymbols::linkMethod_signature(),
2616 &args, CHECK_(empty));
2617 Handle mname(THREAD, (oop) result.get_jobject());
2618 (*method_type_result) = method_type;
2619 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2620 }
2621
2622 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2623 // We must ensure that all class loaders everywhere will reach this class, for any client.
2624 // This is a safe bet for public classes in java.lang, such as Object and String.
2625 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2626 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2627 static bool is_always_visible_class(oop mirror) {
2628 Klass* klass = java_lang_Class::as_Klass(mirror);
2629 if (klass->is_objArray_klass()) {
2630 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2631 }
2632 if (klass->is_typeArray_klass()) {
2633 return true; // primitive array
2634 }
2635 assert(klass->is_instance_klass(), "%s", klass->external_name());
2636 return klass->is_public() &&
2637 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2638 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2639 }
2640
2641 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2642 // signature, as interpreted relative to the given class loader.
2643 // Because of class loader constraints, all method handle usage must be
2644 // consistent with this loader.
2645 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2646 Klass* accessing_klass,
2647 TRAPS) {
2648 Handle empty;
2649 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2650 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2651 int index = invoke_method_table()->hash_to_index(hash);
2652 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2653 if (spe != NULL && spe->method_type() != NULL) {
2654 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2655 return Handle(THREAD, spe->method_type());
2656 } else if (!THREAD->can_call_java()) {
2657 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2658 return Handle(); // do not attempt from within compiler, unless it was cached
2659 }
2660
2661 Handle class_loader, protection_domain;
2662 if (accessing_klass != NULL) {
2663 class_loader = Handle(THREAD, accessing_klass->class_loader());
2664 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2665 }
2666 bool can_be_cached = true;
2667 int npts = ArgumentCount(signature).size();
2668 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2669 int arg = 0;
2670 Handle rt; // the return type from the signature
2671 ResourceMark rm(THREAD);
2672 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2673 oop mirror = NULL;
2674 if (can_be_cached) {
2675 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2676 mirror = ss.as_java_mirror(Handle(), Handle(),
2677 SignatureStream::ReturnNull, CHECK_(empty));
2678 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2679 // Fall back to accessing_klass context.
2680 can_be_cached = false;
2681 }
2682 }
2683 if (!can_be_cached) {
2684 // Resolve, throwing a real error if it doesn't work.
2685 mirror = ss.as_java_mirror(class_loader, protection_domain,
2686 SignatureStream::NCDFError, CHECK_(empty));
2687 }
2688 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2689 if (ss.at_return_type())
2690 rt = Handle(THREAD, mirror);
2691 else
2692 pts->obj_at_put(arg++, mirror);
2693
2694 // Check accessibility.
2695 if (ss.is_object() && accessing_klass != NULL) {
2696 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2697 mirror = NULL; // safety
2698 // Emulate ConstantPool::verify_constant_pool_resolve.
2699 if (sel_klass->is_objArray_klass())
2700 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2701 if (sel_klass->is_instance_klass()) {
2702 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2703 }
2704 }
2705 }
2706 assert(arg == npts, "");
2707
2708 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2709 JavaCallArguments args(Handle(THREAD, rt()));
2710 args.push_oop(pts);
2711 JavaValue result(T_OBJECT);
2712 JavaCalls::call_static(&result,
2713 SystemDictionary::MethodHandleNatives_klass(),
2714 vmSymbols::findMethodHandleType_name(),
2715 vmSymbols::findMethodHandleType_signature(),
2716 &args, CHECK_(empty));
2717 Handle method_type(THREAD, (oop) result.get_jobject());
2718
2719 if (can_be_cached) {
2720 // We can cache this MethodType inside the JVM.
2721 MutexLocker ml(SystemDictionary_lock, THREAD);
2722 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2723 if (spe == NULL)
2724 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2725 if (spe->method_type() == NULL) {
2726 spe->set_method_type(method_type());
2727 }
2728 }
2729
2730 // report back to the caller with the MethodType
2731 return method_type;
2732 }
2733
2734 // Ask Java code to find or construct a method handle constant.
2735 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2736 int ref_kind, //e.g., JVM_REF_invokeVirtual
2737 Klass* callee,
2738 Symbol* name_sym,
2739 Symbol* signature,
2740 TRAPS) {
2741 Handle empty;
2742 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2743 Handle type;
2744 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2745 type = find_method_handle_type(signature, caller, CHECK_(empty));
2746 } else if (caller == NULL) {
2747 // This should not happen. JDK code should take care of that.
2748 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2749 } else {
2750 ResourceMark rm(THREAD);
2751 SignatureStream ss(signature, false);
2752 if (!ss.is_done()) {
2753 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2754 Handle(THREAD, caller->protection_domain()),
2755 SignatureStream::NCDFError, CHECK_(empty));
2756 type = Handle(THREAD, mirror);
2757 ss.next();
2758 if (!ss.is_done()) type = Handle(); // error!
2759 }
2760 }
2761 if (type.is_null()) {
2762 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2763 }
2764
2765 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2766 JavaCallArguments args;
2767 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2768 args.push_int(ref_kind);
2769 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2770 args.push_oop(name);
2771 args.push_oop(type);
2772 JavaValue result(T_OBJECT);
2773 JavaCalls::call_static(&result,
2774 SystemDictionary::MethodHandleNatives_klass(),
2775 vmSymbols::linkMethodHandleConstant_name(),
2776 vmSymbols::linkMethodHandleConstant_signature(),
2777 &args, CHECK_(empty));
2778 return Handle(THREAD, (oop) result.get_jobject());
2779 }
2780
2781 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2782 // name and signature, as interpreted relative to the given class loader.
2783 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2784 Handle bootstrap_specifier,
2785 Symbol* name,
2786 Symbol* type,
2787 Handle *appendix_result,
2788 Handle *method_type_result,
2789 TRAPS) {
2790 methodHandle empty;
2791 Handle bsm, info;
2792 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2793 bsm = bootstrap_specifier;
2794 } else {
2795 assert(bootstrap_specifier->is_objArray(), "");
2796 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2797 int len = args->length();
2798 assert(len >= 1, "");
2799 bsm = Handle(THREAD, args->obj_at(0));
2800 if (len > 1) {
2801 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2802 for (int i = 1; i < len; i++)
2803 args1->obj_at_put(i-1, args->obj_at(i));
2804 info = Handle(THREAD, args1);
2805 }
2806 }
2807 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2808 "caller must supply a valid BSM");
2809
2810 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2811 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2812
2813 // This should not happen. JDK code should take care of that.
2814 if (caller == NULL || method_type.is_null()) {
2815 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2816 }
2817
2818 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2819 assert(appendix_box->obj_at(0) == NULL, "");
2820
2821 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2822 JavaCallArguments args;
2823 args.push_oop(Handle(THREAD, caller->java_mirror()));
2824 args.push_oop(bsm);
2825 args.push_oop(method_name);
2826 args.push_oop(method_type);
2827 args.push_oop(info);
2828 args.push_oop(appendix_box);
2829 JavaValue result(T_OBJECT);
2830 JavaCalls::call_static(&result,
2831 SystemDictionary::MethodHandleNatives_klass(),
2832 vmSymbols::linkCallSite_name(),
2833 vmSymbols::linkCallSite_signature(),
2834 &args, CHECK_(empty));
2835 Handle mname(THREAD, (oop) result.get_jobject());
2836 (*method_type_result) = method_type;
2837 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2838 }
2839
2840 // Since the identity hash code for symbols changes when the symbols are
2841 // moved from the regular perm gen (hash in the mark word) to the shared
2842 // spaces (hash is the address), the classes loaded into the dictionary
2843 // may be in the wrong buckets.
2844
2845 void SystemDictionary::reorder_dictionary() {
2846 dictionary()->reorder_dictionary();
2847 }
2848
2849
2850 void SystemDictionary::copy_buckets(char** top, char* end) {
2851 dictionary()->copy_buckets(top, end);
2852 }
2853
2854
2855 void SystemDictionary::copy_table(char** top, char* end) {
2856 dictionary()->copy_table(top, end);
2857 }
2858
2859 int SystemDictionary::number_of_classes() {
2860 return dictionary()->number_of_entries();
2861 }
2862
2863
2864 // ----------------------------------------------------------------------------
2865 void SystemDictionary::print_shared(bool details) {
2866 shared_dictionary()->print(details);
2867 }
2868
2869 void SystemDictionary::print(bool details) {
2870 dictionary()->print(details);
2871
2872 // Placeholders
2873 GCMutexLocker mu(SystemDictionary_lock);
2874 placeholders()->print();
2875
2876 // loader constraints - print under SD_lock
2877 constraints()->print();
2878 }
2879
2880
2881 void SystemDictionary::verify() {
2882 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2883 guarantee(constraints() != NULL,
2884 "Verify of loader constraints failed");
2885 guarantee(dictionary()->number_of_entries() >= 0 &&
2886 placeholders()->number_of_entries() >= 0,
2887 "Verify of system dictionary failed");
2888
2889 // Verify dictionary
2890 dictionary()->verify();
2891
2892 GCMutexLocker mu(SystemDictionary_lock);
2893 placeholders()->verify();
2894
2895 // Verify constraint table
2896 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2897 constraints()->verify(dictionary(), placeholders());
2898 }
2899
2900 // caller needs ResourceMark
2901 const char* SystemDictionary::loader_name(const oop loader) {
2902 return ((loader) == NULL ? "<bootloader>" :
2903 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2904 }
2905
2906 // caller needs ResourceMark
2907 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2908 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2909 SystemDictionary::loader_name(loader_data->class_loader()));
2910 }