1 /*
2 * Copyright (c) 1997, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/resolutionErrors.hpp"
39 #include "classfile/stringTable.hpp"
40 #include "classfile/systemDictionary.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "code/codeCache.hpp"
43 #include "compiler/compileBroker.hpp"
44 #include "gc/shared/gcLocker.hpp"
45 #include "interpreter/bytecodeStream.hpp"
46 #include "interpreter/interpreter.hpp"
47 #include "memory/filemap.hpp"
48 #include "memory/oopFactory.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/instanceRefKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/methodData.hpp"
54 #include "oops/objArrayKlass.hpp"
55 #include "oops/objArrayOop.inline.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayKlass.hpp"
59 #include "prims/jvmtiEnvBase.hpp"
60 #include "prims/methodHandles.hpp"
61 #include "runtime/arguments.hpp"
62 #include "runtime/biasedLocking.hpp"
63 #include "runtime/fieldType.hpp"
64 #include "runtime/handles.inline.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/mutexLocker.hpp"
68 #include "runtime/orderAccess.inline.hpp"
69 #include "runtime/signature.hpp"
70 #include "services/classLoadingService.hpp"
71 #include "services/threadService.hpp"
72 #include "trace/traceMacros.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/ticks.hpp"
75 #if INCLUDE_CDS
76 #include "classfile/sharedClassUtil.hpp"
77 #include "classfile/systemDictionaryShared.hpp"
78 #endif
79 #if INCLUDE_JVMCI
80 #include "jvmci/jvmciRuntime.hpp"
81 #endif
82 #if INCLUDE_TRACE
83 #include "trace/tracing.hpp"
84 #endif
85
86 Dictionary* SystemDictionary::_dictionary = NULL;
87 PlaceholderTable* SystemDictionary::_placeholders = NULL;
88 Dictionary* SystemDictionary::_shared_dictionary = NULL;
89 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
90 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
91 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
92
93
94 int SystemDictionary::_number_of_modifications = 0;
95 int SystemDictionary::_sdgeneration = 0;
96 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
97 20201,40423,99991};
98
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107
108 bool SystemDictionary::_has_loadClassInternal = false;
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114
115 // ----------------------------------------------------------------------------
116 // Java-level SystemLoader
117
118 oop SystemDictionary::java_system_loader() {
119 return _java_system_loader;
120 }
121
122 void SystemDictionary::compute_java_system_loader(TRAPS) {
123 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
124 JavaValue result(T_OBJECT);
125 JavaCalls::call_static(&result,
126 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
127 vmSymbols::getSystemClassLoader_name(),
128 vmSymbols::void_classloader_signature(),
129 CHECK);
130
131 _java_system_loader = (oop)result.get_jobject();
132
133 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
134 }
135
136
137 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
138 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
139 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
140 }
141
142 // ----------------------------------------------------------------------------
143 // Parallel class loading check
144
145 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
146 if (UnsyncloadClass || class_loader.is_null()) return true;
147 if (AlwaysLockClassLoader) return false;
148 return java_lang_ClassLoader::parallelCapable(class_loader());
149 }
150 // ----------------------------------------------------------------------------
151 // ParallelDefineClass flag does not apply to bootclass loader
152 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
153 if (class_loader.is_null()) return false;
154 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
155 return true;
156 }
157 return false;
158 }
159
160 // Returns true if the passed class loader is the builtin application class loader
161 // or a custom system class loader. A customer system class loader can be
162 // specified via -Djava.system.class.loader.
163 bool SystemDictionary::is_system_class_loader(Handle class_loader) {
164 if (class_loader.is_null()) {
165 return false;
166 }
167 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
168 class_loader() == _java_system_loader);
169 }
170
171 // Returns true if the passed class loader is the platform class loader.
172 bool SystemDictionary::is_platform_class_loader(Handle class_loader) {
173 if (class_loader.is_null()) {
174 return false;
175 }
176 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
177 }
178
179 // ----------------------------------------------------------------------------
180 // Resolving of classes
181
182 // Forwards to resolve_or_null
183
184 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
185 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
186 if (HAS_PENDING_EXCEPTION || klass == NULL) {
187 KlassHandle k_h(THREAD, klass);
188 // can return a null klass
189 klass = handle_resolution_exception(class_name, throw_error, k_h, THREAD);
190 }
191 return klass;
192 }
193
194 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
195 bool throw_error,
196 KlassHandle klass_h, 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_h() == 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_h() == 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*)klass_h();
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 KlassHandle superk_h(THREAD, superk);
406
407 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
408 // It is no longer necessary to keep the placeholder table alive until update_dictionary
409 // or error. GC used to walk the placeholder table as strong roots.
410 // The instanceKlass is kept alive because the class loader is on the stack,
411 // which keeps the loader_data alive, as well as all instanceKlasses in
412 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
413 {
414 MutexLocker mu(SystemDictionary_lock, THREAD);
415 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
416 SystemDictionary_lock->notify_all();
417 }
418 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
419 // can null superk
420 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, true, superk_h, THREAD));
421 }
422
423 return superk_h();
424 }
425
426 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
427 Handle class_loader,
428 Handle protection_domain,
429 TRAPS) {
430 if(!has_checkPackageAccess()) return;
431
432 // Now we have to call back to java to check if the initating class has access
433 JavaValue result(T_VOID);
434 if (log_is_enabled(Debug, protectiondomain)) {
435 ResourceMark rm;
436 // Print out trace information
437 outputStream* log = Log(protectiondomain)::debug_stream();
438 log->print_cr("Checking package access");
439 log->print("class loader: "); class_loader()->print_value_on(log);
440 log->print(" protection domain: "); protection_domain()->print_value_on(log);
441 log->print(" loading: "); klass()->print_value_on(log);
442 log->cr();
443 }
444
445 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
446 JavaCalls::call_special(&result,
447 class_loader,
448 system_loader,
449 vmSymbols::checkPackageAccess_name(),
450 vmSymbols::class_protectiondomain_signature(),
451 Handle(THREAD, klass->java_mirror()),
452 protection_domain,
453 THREAD);
454
455 if (HAS_PENDING_EXCEPTION) {
456 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
457 } else {
458 log_debug(protectiondomain)("granted");
459 }
460
461 if (HAS_PENDING_EXCEPTION) return;
462
463 // If no exception has been thrown, we have validated the protection domain
464 // Insert the protection domain of the initiating class into the set.
465 {
466 // We recalculate the entry here -- we've called out to java since
467 // the last time it was calculated.
468 ClassLoaderData* loader_data = class_loader_data(class_loader);
469
470 Symbol* kn = klass->name();
471 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
472 int d_index = dictionary()->hash_to_index(d_hash);
473
474 MutexLocker mu(SystemDictionary_lock, THREAD);
475 {
476 // Note that we have an entry, and entries can be deleted only during GC,
477 // so we cannot allow GC to occur while we're holding this entry.
478
479 // We're using a NoSafepointVerifier to catch any place where we
480 // might potentially do a GC at all.
481 // Dictionary::do_unloading() asserts that classes in SD are only
482 // unloaded at a safepoint. Anonymous classes are not in SD.
483 NoSafepointVerifier nosafepoint;
484 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
485 protection_domain, THREAD);
486 }
487 }
488 }
489
490 // We only get here if this thread finds that another thread
491 // has already claimed the placeholder token for the current operation,
492 // but that other thread either never owned or gave up the
493 // object lock
494 // Waits on SystemDictionary_lock to indicate placeholder table updated
495 // On return, caller must recheck placeholder table state
496 //
497 // We only get here if
498 // 1) custom classLoader, i.e. not bootstrap classloader
499 // 2) UnsyncloadClass not set
500 // 3) custom classLoader has broken the class loader objectLock
501 // so another thread got here in parallel
502 //
503 // lockObject must be held.
504 // Complicated dance due to lock ordering:
505 // Must first release the classloader object lock to
506 // allow initial definer to complete the class definition
507 // and to avoid deadlock
508 // Reclaim classloader lock object with same original recursion count
509 // Must release SystemDictionary_lock after notify, since
510 // class loader lock must be claimed before SystemDictionary_lock
511 // to prevent deadlocks
512 //
513 // The notify allows applications that did an untimed wait() on
514 // the classloader object lock to not hang.
515 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
516 assert_lock_strong(SystemDictionary_lock);
517
518 bool calledholdinglock
519 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
520 assert(calledholdinglock,"must hold lock for notify");
521 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
522 ObjectSynchronizer::notifyall(lockObject, THREAD);
523 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
524 SystemDictionary_lock->wait();
525 SystemDictionary_lock->unlock();
526 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
527 SystemDictionary_lock->lock();
528 }
529
530 // If the class in is in the placeholder table, class loading is in progress
531 // For cases where the application changes threads to load classes, it
532 // is critical to ClassCircularity detection that we try loading
533 // the superclass on the same thread internally, so we do parallel
534 // super class loading here.
535 // This also is critical in cases where the original thread gets stalled
536 // even in non-circularity situations.
537 // Note: must call resolve_super_or_fail even if null super -
538 // to force placeholder entry creation for this class for circularity detection
539 // Caller must check for pending exception
540 // Returns non-null Klass* if other thread has completed load
541 // and we are done,
542 // If return null Klass* and no pending exception, the caller must load the class
543 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
544 Symbol* name, Symbol* superclassname, Handle class_loader,
545 Handle protection_domain, Handle lockObject, TRAPS) {
546
547 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
548 ClassLoaderData* loader_data = class_loader_data(class_loader);
549 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
550 int d_index = dictionary()->hash_to_index(d_hash);
551 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
552 int p_index = placeholders()->hash_to_index(p_hash);
553
554 // superk is not used, resolve_super called for circularity check only
555 // This code is reached in two situations. One if this thread
556 // is loading the same class twice (e.g. ClassCircularity, or
557 // java.lang.instrument).
558 // The second is if another thread started the resolve_super first
559 // and has not yet finished.
560 // In both cases the original caller will clean up the placeholder
561 // entry on error.
562 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
563 superclassname,
564 class_loader,
565 protection_domain,
566 true,
567 CHECK_(nh));
568
569 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
570 // Serial class loaders and bootstrap classloader do wait for superclass loads
571 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
572 MutexLocker mu(SystemDictionary_lock, THREAD);
573 // Check if classloading completed while we were loading superclass or waiting
574 Klass* check = find_class(d_index, d_hash, name, loader_data);
575 if (check != NULL) {
576 // Klass is already loaded, so just return it
577 return(instanceKlassHandle(THREAD, check));
578 } else {
579 return nh;
580 }
581 }
582
583 // must loop to both handle other placeholder updates
584 // and spurious notifications
585 bool super_load_in_progress = true;
586 PlaceholderEntry* placeholder;
587 while (super_load_in_progress) {
588 MutexLocker mu(SystemDictionary_lock, THREAD);
589 // Check if classloading completed while we were loading superclass or waiting
590 Klass* check = find_class(d_index, d_hash, name, loader_data);
591 if (check != NULL) {
592 // Klass is already loaded, so just return it
593 return(instanceKlassHandle(THREAD, check));
594 } else {
595 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
596 if (placeholder && placeholder->super_load_in_progress() ){
597 // Before UnsyncloadClass:
598 // We only get here if the application has released the
599 // classloader lock when another thread was in the middle of loading a
600 // superclass/superinterface for this class, and now
601 // this thread is also trying to load this class.
602 // To minimize surprises, the first thread that started to
603 // load a class should be the one to complete the loading
604 // with the classfile it initially expected.
605 // This logic has the current thread wait once it has done
606 // all the superclass/superinterface loading it can, until
607 // the original thread completes the class loading or fails
608 // If it completes we will use the resulting InstanceKlass
609 // which we will find below in the systemDictionary.
610 // We also get here for parallel bootstrap classloader
611 if (class_loader.is_null()) {
612 SystemDictionary_lock->wait();
613 } else {
614 double_lock_wait(lockObject, THREAD);
615 }
616 } else {
617 // If not in SD and not in PH, other thread's load must have failed
618 super_load_in_progress = false;
619 }
620 }
621 }
622 return (nh);
623 }
624
625 // utility function for class load event
626 static void post_class_load_event(const Ticks& start_time,
627 instanceKlassHandle k,
628 Handle initiating_loader) {
629 #if INCLUDE_TRACE
630 EventClassLoad event(UNTIMED);
631 if (event.should_commit()) {
632 event.set_starttime(start_time);
633 event.set_loadedClass(k());
634 oop defining_class_loader = k->class_loader();
635 event.set_definingClassLoader(defining_class_loader != NULL ?
636 defining_class_loader->klass() : (Klass*)NULL);
637 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
638 event.set_initiatingClassLoader(class_loader != NULL ?
639 class_loader->klass() : (Klass*)NULL);
640 event.commit();
641 }
642 #endif // INCLUDE_TRACE
643 }
644
645 // utility function for class define event
646 static void class_define_event(instanceKlassHandle k) {
647 #if INCLUDE_TRACE
648 EventClassDefine event(UNTIMED);
649 if (event.should_commit()) {
650 event.set_definedClass(k());
651 oop defining_class_loader = k->class_loader();
652 event.set_definingClassLoader(defining_class_loader != NULL ?
653 defining_class_loader->klass() : (Klass*)NULL);
654 event.commit();
655 }
656 #endif // INCLUDE_TRACE
657 }
658
659 // Be careful when modifying this code: once you have run
660 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
661 // you need to find_and_remove it before returning.
662 // So be careful to not exit with a CHECK_ macro betweeen these calls.
663 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
664 Handle class_loader,
665 Handle protection_domain,
666 TRAPS) {
667 assert(name != NULL && !FieldType::is_array(name) &&
668 !FieldType::is_obj(name), "invalid class name");
669
670 Ticks class_load_start_time = Ticks::now();
671
672 // Fix for 4474172; see evaluation for more details
673 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
674 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
675
676 // Do lookup to see if class already exist and the protection domain
677 // has the right access
678 // This call uses find which checks protection domain already matches
679 // All subsequent calls use find_class, and set has_loaded_class so that
680 // before we return a result we call out to java to check for valid protection domain
681 // to allow returning the Klass* and add it to the pd_set if it is valid
682 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
683 int d_index = dictionary()->hash_to_index(d_hash);
684 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
685 protection_domain, THREAD);
686 if (probe != NULL) return probe;
687
688
689 // Non-bootstrap class loaders will call out to class loader and
690 // define via jvm/jni_DefineClass which will acquire the
691 // class loader object lock to protect against multiple threads
692 // defining the class in parallel by accident.
693 // This lock must be acquired here so the waiter will find
694 // any successful result in the SystemDictionary and not attempt
695 // the define
696 // ParallelCapable Classloaders and the bootstrap classloader,
697 // or all classloaders with UnsyncloadClass do not acquire lock here
698 bool DoObjectLock = true;
699 if (is_parallelCapable(class_loader)) {
700 DoObjectLock = false;
701 }
702
703 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
704 int p_index = placeholders()->hash_to_index(p_hash);
705
706 // Class is not in SystemDictionary so we have to do loading.
707 // Make sure we are synchronized on the class loader before we proceed
708 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
709 check_loader_lock_contention(lockObject, THREAD);
710 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
711
712 // Check again (after locking) if class already exist in SystemDictionary
713 bool class_has_been_loaded = false;
714 bool super_load_in_progress = false;
715 bool havesupername = false;
716 instanceKlassHandle k;
717 PlaceholderEntry* placeholder;
718 Symbol* superclassname = NULL;
719
720 {
721 MutexLocker mu(SystemDictionary_lock, THREAD);
722 Klass* check = find_class(d_index, d_hash, name, loader_data);
723 if (check != NULL) {
724 // Klass is already loaded, so just return it
725 class_has_been_loaded = true;
726 k = instanceKlassHandle(THREAD, check);
727 } else {
728 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
729 if (placeholder && placeholder->super_load_in_progress()) {
730 super_load_in_progress = true;
731 if (placeholder->havesupername() == true) {
732 superclassname = placeholder->supername();
733 havesupername = true;
734 }
735 }
736 }
737 }
738
739 // If the class is in the placeholder table, class loading is in progress
740 if (super_load_in_progress && havesupername==true) {
741 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
742 class_loader, protection_domain, lockObject, THREAD);
743 if (HAS_PENDING_EXCEPTION) {
744 return NULL;
745 }
746 if (!k.is_null()) {
747 class_has_been_loaded = true;
748 }
749 }
750
751 bool throw_circularity_error = false;
752 if (!class_has_been_loaded) {
753 bool load_instance_added = false;
754
755 // add placeholder entry to record loading instance class
756 // Five cases:
757 // All cases need to prevent modifying bootclasssearchpath
758 // in parallel with a classload of same classname
759 // Redefineclasses uses existence of the placeholder for the duration
760 // of the class load to prevent concurrent redefinition of not completely
761 // defined classes.
762 // case 1. traditional classloaders that rely on the classloader object lock
763 // - no other need for LOAD_INSTANCE
764 // case 2. traditional classloaders that break the classloader object lock
765 // as a deadlock workaround. Detection of this case requires that
766 // this check is done while holding the classloader object lock,
767 // and that lock is still held when calling classloader's loadClass.
768 // For these classloaders, we ensure that the first requestor
769 // completes the load and other requestors wait for completion.
770 // case 3. UnsyncloadClass - don't use objectLocker
771 // With this flag, we allow parallel classloading of a
772 // class/classloader pair
773 // case4. Bootstrap classloader - don't own objectLocker
774 // This classloader supports parallelism at the classloader level,
775 // but only allows a single load of a class/classloader pair.
776 // No performance benefit and no deadlock issues.
777 // case 5. parallelCapable user level classloaders - without objectLocker
778 // Allow parallel classloading of a class/classloader pair
779
780 {
781 MutexLocker mu(SystemDictionary_lock, THREAD);
782 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
783 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
784 if (oldprobe) {
785 // only need check_seen_thread once, not on each loop
786 // 6341374 java/lang/Instrument with -Xcomp
787 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
788 throw_circularity_error = true;
789 } else {
790 // case 1: traditional: should never see load_in_progress.
791 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
792
793 // case 4: bootstrap classloader: prevent futile classloading,
794 // wait on first requestor
795 if (class_loader.is_null()) {
796 SystemDictionary_lock->wait();
797 } else {
798 // case 2: traditional with broken classloader lock. wait on first
799 // requestor.
800 double_lock_wait(lockObject, THREAD);
801 }
802 // Check if classloading completed while we were waiting
803 Klass* check = find_class(d_index, d_hash, name, loader_data);
804 if (check != NULL) {
805 // Klass is already loaded, so just return it
806 k = instanceKlassHandle(THREAD, check);
807 class_has_been_loaded = true;
808 }
809 // check if other thread failed to load and cleaned up
810 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
811 }
812 }
813 }
814 }
815 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
816 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
817 // LOAD_INSTANCE in parallel
818
819 if (!throw_circularity_error && !class_has_been_loaded) {
820 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
821 load_instance_added = true;
822 // For class loaders that do not acquire the classloader object lock,
823 // if they did not catch another thread holding LOAD_INSTANCE,
824 // need a check analogous to the acquire ObjectLocker/find_class
825 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
826 // one final check if the load has already completed
827 // class loaders holding the ObjectLock shouldn't find the class here
828 Klass* check = find_class(d_index, d_hash, name, loader_data);
829 if (check != NULL) {
830 // Klass is already loaded, so return it after checking/adding protection domain
831 k = instanceKlassHandle(THREAD, check);
832 class_has_been_loaded = true;
833 }
834 }
835 }
836
837 // must throw error outside of owning lock
838 if (throw_circularity_error) {
839 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
840 ResourceMark rm(THREAD);
841 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
842 }
843
844 if (!class_has_been_loaded) {
845
846 // Do actual loading
847 k = load_instance_class(name, class_loader, THREAD);
848
849 // For UnsyncloadClass only
850 // If they got a linkageError, check if a parallel class load succeeded.
851 // If it did, then for bytecode resolution the specification requires
852 // that we return the same result we did for the other thread, i.e. the
853 // successfully loaded InstanceKlass
854 // Should not get here for classloaders that support parallelism
855 // with the new cleaner mechanism, even with AllowParallelDefineClass
856 // Bootstrap goes through here to allow for an extra guarantee check
857 if (UnsyncloadClass || (class_loader.is_null())) {
858 if (k.is_null() && HAS_PENDING_EXCEPTION
859 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
860 MutexLocker mu(SystemDictionary_lock, THREAD);
861 Klass* check = find_class(d_index, d_hash, name, loader_data);
862 if (check != NULL) {
863 // Klass is already loaded, so just use it
864 k = instanceKlassHandle(THREAD, check);
865 CLEAR_PENDING_EXCEPTION;
866 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
867 }
868 }
869 }
870
871 // If everything was OK (no exceptions, no null return value), and
872 // class_loader is NOT the defining loader, do a little more bookkeeping.
873 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
874 k->class_loader() != class_loader()) {
875
876 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
877
878 // Need to check for a PENDING_EXCEPTION again; check_constraints
879 // can throw and doesn't use the CHECK macro.
880 if (!HAS_PENDING_EXCEPTION) {
881 { // Grabbing the Compile_lock prevents systemDictionary updates
882 // during compilations.
883 MutexLocker mu(Compile_lock, THREAD);
884 update_dictionary(d_index, d_hash, p_index, p_hash,
885 k, class_loader, THREAD);
886 }
887
888 if (JvmtiExport::should_post_class_load()) {
889 Thread *thread = THREAD;
890 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
891 JvmtiExport::post_class_load((JavaThread *) thread, k());
892 }
893 }
894 }
895 } // load_instance_class loop
896
897 if (load_instance_added == true) {
898 // clean up placeholder entries for LOAD_INSTANCE success or error
899 // This brackets the SystemDictionary updates for both defining
900 // and initiating loaders
901 MutexLocker mu(SystemDictionary_lock, THREAD);
902 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
903 SystemDictionary_lock->notify_all();
904 }
905 }
906
907 if (HAS_PENDING_EXCEPTION || k.is_null()) {
908 return NULL;
909 }
910
911 post_class_load_event(class_load_start_time, k, class_loader);
912
913 #ifdef ASSERT
914 {
915 ClassLoaderData* loader_data = k->class_loader_data();
916 MutexLocker mu(SystemDictionary_lock, THREAD);
917 Klass* kk = find_class(name, loader_data);
918 assert(kk == k(), "should be present in dictionary");
919 }
920 #endif
921
922 // return if the protection domain in NULL
923 if (protection_domain() == NULL) return k();
924
925 // Check the protection domain has the right access
926 {
927 MutexLocker mu(SystemDictionary_lock, THREAD);
928 // Note that we have an entry, and entries can be deleted only during GC,
929 // so we cannot allow GC to occur while we're holding this entry.
930 // We're using a NoSafepointVerifier to catch any place where we
931 // might potentially do a GC at all.
932 // Dictionary::do_unloading() asserts that classes in SD are only
933 // unloaded at a safepoint. Anonymous classes are not in SD.
934 NoSafepointVerifier nosafepoint;
935 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
936 loader_data,
937 protection_domain)) {
938 return k();
939 }
940 }
941
942 // Verify protection domain. If it fails an exception is thrown
943 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
944
945 return k();
946 }
947
948
949 // This routine does not lock the system dictionary.
950 //
951 // Since readers don't hold a lock, we must make sure that system
952 // dictionary entries are only removed at a safepoint (when only one
953 // thread is running), and are added to in a safe way (all links must
954 // be updated in an MT-safe manner).
955 //
956 // Callers should be aware that an entry could be added just after
957 // _dictionary->bucket(index) is read here, so the caller will not see
958 // the new entry.
959
960 Klass* SystemDictionary::find(Symbol* class_name,
961 Handle class_loader,
962 Handle protection_domain,
963 TRAPS) {
964
965 // The result of this call should be consistent with the result
966 // of the call to resolve_instance_class_or_null().
967 // See evaluation 6790209 and 4474172 for more details.
968 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
969 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
970
971 if (loader_data == NULL) {
972 // If the ClassLoaderData has not been setup,
973 // then the class loader has no entries in the dictionary.
974 return NULL;
975 }
976
977 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
978 int d_index = dictionary()->hash_to_index(d_hash);
979
980 {
981 // Note that we have an entry, and entries can be deleted only during GC,
982 // so we cannot allow GC to occur while we're holding this entry.
983 // We're using a NoSafepointVerifier to catch any place where we
984 // might potentially do a GC at all.
985 // Dictionary::do_unloading() asserts that classes in SD are only
986 // unloaded at a safepoint. Anonymous classes are not in SD.
987 NoSafepointVerifier nosafepoint;
988 return dictionary()->find(d_index, d_hash, class_name, loader_data,
989 protection_domain, THREAD);
990 }
991 }
992
993
994 // Look for a loaded instance or array klass by name. Do not do any loading.
995 // return NULL in case of error.
996 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
997 Handle class_loader,
998 Handle protection_domain,
999 TRAPS) {
1000 Klass* k = NULL;
1001 assert(class_name != NULL, "class name must be non NULL");
1002
1003 if (FieldType::is_array(class_name)) {
1004 // The name refers to an array. Parse the name.
1005 // dimension and object_key in FieldArrayInfo are assigned as a
1006 // side-effect of this call
1007 FieldArrayInfo fd;
1008 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1009 if (t != T_OBJECT) {
1010 k = Universe::typeArrayKlassObj(t);
1011 } else {
1012 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1013 }
1014 if (k != NULL) {
1015 k = k->array_klass_or_null(fd.dimension());
1016 }
1017 } else {
1018 k = find(class_name, class_loader, protection_domain, THREAD);
1019 }
1020 return k;
1021 }
1022
1023 // Note: this method is much like resolve_from_stream, but
1024 // does not publish the classes via the SystemDictionary.
1025 // Handles unsafe_DefineAnonymousClass and redefineclasses
1026 // RedefinedClasses do not add to the class hierarchy
1027 Klass* SystemDictionary::parse_stream(Symbol* class_name,
1028 Handle class_loader,
1029 Handle protection_domain,
1030 ClassFileStream* st,
1031 const InstanceKlass* host_klass,
1032 GrowableArray<Handle>* cp_patches,
1033 TRAPS) {
1034
1035 Ticks class_load_start_time = Ticks::now();
1036
1037 ClassLoaderData* loader_data;
1038 if (host_klass != NULL) {
1039 // Create a new CLD for anonymous class, that uses the same class loader
1040 // as the host_klass
1041 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1042 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1043 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1044 loader_data->record_dependency(host_klass, CHECK_NULL);
1045 } else {
1046 loader_data = ClassLoaderData::class_loader_data(class_loader());
1047 }
1048
1049 assert(st != NULL, "invariant");
1050 assert(st->need_verify(), "invariant");
1051
1052 // Parse stream and create a klass.
1053 // Note that we do this even though this klass might
1054 // already be present in the SystemDictionary, otherwise we would not
1055 // throw potential ClassFormatErrors.
1056
1057 instanceKlassHandle k = KlassFactory::create_from_stream(st,
1058 class_name,
1059 loader_data,
1060 protection_domain,
1061 host_klass,
1062 cp_patches,
1063 CHECK_NULL);
1064
1065 if (host_klass != NULL && k.not_null()) {
1066 // If it's anonymous, initialize it now, since nobody else will.
1067
1068 {
1069 MutexLocker mu_r(Compile_lock, THREAD);
1070
1071 // Add to class hierarchy, initialize vtables, and do possible
1072 // deoptimizations.
1073 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1074
1075 // But, do not add to system dictionary.
1076
1077 // compiled code dependencies need to be validated anyway
1078 notice_modification();
1079 }
1080
1081 // Rewrite and patch constant pool here.
1082 k->link_class(CHECK_NULL);
1083 if (cp_patches != NULL) {
1084 k->constants()->patch_resolved_references(cp_patches);
1085 }
1086 k->eager_initialize(CHECK_NULL);
1087
1088 // notify jvmti
1089 if (JvmtiExport::should_post_class_load()) {
1090 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1091 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1092 }
1093
1094 post_class_load_event(class_load_start_time, k, class_loader);
1095 }
1096 assert(host_klass != NULL || NULL == cp_patches,
1097 "cp_patches only found with host_klass");
1098
1099 return k();
1100 }
1101
1102 // Add a klass to the system from a stream (called by jni_DefineClass and
1103 // JVM_DefineClass).
1104 // Note: class_name can be NULL. In that case we do not know the name of
1105 // the class until we have parsed the stream.
1106
1107 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1108 Handle class_loader,
1109 Handle protection_domain,
1110 ClassFileStream* st,
1111 TRAPS) {
1112
1113 // Classloaders that support parallelism, e.g. bootstrap classloader,
1114 // or all classloaders with UnsyncloadClass do not acquire lock here
1115 bool DoObjectLock = true;
1116 if (is_parallelCapable(class_loader)) {
1117 DoObjectLock = false;
1118 }
1119
1120 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1121
1122 // Make sure we are synchronized on the class loader before we proceed
1123 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1124 check_loader_lock_contention(lockObject, THREAD);
1125 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1126
1127 assert(st != NULL, "invariant");
1128
1129 // Parse the stream and create a klass.
1130 // Note that we do this even though this klass might
1131 // already be present in the SystemDictionary, otherwise we would not
1132 // throw potential ClassFormatErrors.
1133 //
1134
1135 instanceKlassHandle k;
1136
1137 #if INCLUDE_CDS
1138 k = SystemDictionaryShared::lookup_from_stream(class_name,
1139 class_loader,
1140 protection_domain,
1141 st,
1142 CHECK_NULL);
1143 #endif
1144
1145 if (k.is_null()) {
1146 if (st->buffer() == NULL) {
1147 return NULL;
1148 }
1149 k = KlassFactory::create_from_stream(st,
1150 class_name,
1151 loader_data,
1152 protection_domain,
1153 NULL, // host_klass
1154 NULL, // cp_patches
1155 CHECK_NULL);
1156 }
1157
1158 assert(k.not_null(), "no klass created");
1159 Symbol* h_name = k->name();
1160 assert(class_name == NULL || class_name == h_name, "name mismatch");
1161
1162 bool define_succeeded = false;
1163 // Add class just loaded
1164 // If a class loader supports parallel classloading handle parallel define requests
1165 // find_or_define_instance_class may return a different InstanceKlass
1166 if (is_parallelCapable(class_loader)) {
1167 instanceKlassHandle defined_k = find_or_define_instance_class(h_name, class_loader, k, CHECK_NULL);
1168 if (k() == defined_k()) {
1169 // we have won over other concurrent threads (if any) that are
1170 // competing to define the same class.
1171 define_succeeded = true;
1172 }
1173 k = defined_k;
1174 } else {
1175 define_instance_class(k, CHECK_NULL);
1176 define_succeeded = true;
1177 }
1178
1179 // Make sure we have an entry in the SystemDictionary on success
1180 debug_only( {
1181 MutexLocker mu(SystemDictionary_lock, THREAD);
1182
1183 Klass* check = find_class(h_name, k->class_loader_data());
1184 assert(check == k(), "should be present in the dictionary");
1185 } );
1186
1187 return k();
1188 }
1189
1190 #if INCLUDE_CDS
1191 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1192 int number_of_entries) {
1193 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1194 "bad shared dictionary size.");
1195 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1196 }
1197
1198
1199 // If there is a shared dictionary, then find the entry for the
1200 // given shared system class, if any.
1201
1202 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1203 if (shared_dictionary() != NULL) {
1204 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1205 int d_index = shared_dictionary()->hash_to_index(d_hash);
1206
1207 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1208 } else {
1209 return NULL;
1210 }
1211 }
1212
1213
1214 // Load a class from the shared spaces (found through the shared system
1215 // dictionary). Force the superclass and all interfaces to be loaded.
1216 // Update the class definition to include sibling classes and no
1217 // subclasses (yet). [Classes in the shared space are not part of the
1218 // object hierarchy until loaded.]
1219
1220 instanceKlassHandle SystemDictionary::load_shared_class(
1221 Symbol* class_name, Handle class_loader, TRAPS) {
1222 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1223 // Make sure we only return the boot class for the NULL classloader.
1224 if (ik.not_null() &&
1225 ik->is_shared_boot_class() && class_loader.is_null()) {
1226 Handle protection_domain;
1227 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1228 }
1229 return instanceKlassHandle();
1230 }
1231
1232 // Check if a shared class can be loaded by the specific classloader:
1233 //
1234 // NULL classloader:
1235 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1236 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1237 // be defined in an unnamed module.
1238 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1239 instanceKlassHandle ik,
1240 Handle class_loader, TRAPS) {
1241 ResourceMark rm;
1242 int path_index = ik->shared_classpath_index();
1243 SharedClassPathEntry* ent =
1244 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1245 if (!Universe::is_module_initialized()) {
1246 assert(ent != NULL && ent->is_jrt(),
1247 "Loading non-bootstrap classes before the module system is initialized");
1248 assert(class_loader.is_null(), "sanity");
1249 return true;
1250 }
1251 // Get the pkg_entry from the classloader
1252 TempNewSymbol pkg_name = NULL;
1253 PackageEntry* pkg_entry = NULL;
1254 ModuleEntry* mod_entry = NULL;
1255 const char* pkg_string = NULL;
1256 ClassLoaderData* loader_data = class_loader_data(class_loader);
1257 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1258 if (pkg_name != NULL) {
1259 pkg_string = pkg_name->as_C_string();
1260 if (loader_data != NULL) {
1261 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1262 }
1263 if (pkg_entry != NULL) {
1264 mod_entry = pkg_entry->module();
1265 }
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->modules()->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 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1309 Handle class_loader,
1310 Handle protection_domain, TRAPS) {
1311 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1312
1313 if (ik.not_null()) {
1314 Symbol* class_name = ik->name();
1315
1316 bool visible = is_shared_class_visible(
1317 class_name, ik, class_loader, CHECK_(nh));
1318 if (!visible) {
1319 return nh;
1320 }
1321
1322 // Resolve the superclass and interfaces. They must be the same
1323 // as in dump time, because the layout of <ik> depends on
1324 // the specific layout of ik->super() and ik->local_interfaces().
1325 //
1326 // If unexpected superclass or interfaces are found, we cannot
1327 // load <ik> from the shared archive.
1328
1329 if (ik->super() != NULL) {
1330 Symbol* cn = ik->super()->name();
1331 Klass *s = resolve_super_or_fail(class_name, cn,
1332 class_loader, protection_domain, true, CHECK_(nh));
1333 if (s != ik->super()) {
1334 // The dynamically resolved super class is not the same as the one we used during dump time,
1335 // so we cannot use ik.
1336 return nh;
1337 } else {
1338 assert(s->is_shared(), "must be");
1339 }
1340 }
1341
1342 Array<Klass*>* interfaces = ik->local_interfaces();
1343 int num_interfaces = interfaces->length();
1344 for (int index = 0; index < num_interfaces; index++) {
1345 Klass* k = interfaces->at(index);
1346
1347 // Note: can not use InstanceKlass::cast here because
1348 // interfaces' InstanceKlass's C++ vtbls haven't been
1349 // reinitialized yet (they will be once the interface classes
1350 // are loaded)
1351 Symbol* name = k->name();
1352 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1353 if (k != i) {
1354 // The dynamically resolved interface class is not the same as the one we used during dump time,
1355 // so we cannot use ik.
1356 return nh;
1357 } else {
1358 assert(i->is_shared(), "must be");
1359 }
1360 }
1361
1362 instanceKlassHandle new_ik = KlassFactory::check_shared_class_file_load_hook(
1363 ik, class_name, class_loader, protection_domain, CHECK_(nh));
1364 if (new_ik.not_null()) {
1365 // The class is changed by CFLH. Return the new class. The shared class is
1366 // not used.
1367 return new_ik;
1368 }
1369
1370 // Adjust methods to recover missing data. They need addresses for
1371 // interpreter entry points and their default native method address
1372 // must be reset.
1373
1374 // Updating methods must be done under a lock so multiple
1375 // threads don't update these in parallel
1376 //
1377 // Shared classes are all currently loaded by either the bootstrap or
1378 // internal parallel class loaders, so this will never cause a deadlock
1379 // on a custom class loader lock.
1380
1381 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1382 {
1383 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1384 check_loader_lock_contention(lockObject, THREAD);
1385 ObjectLocker ol(lockObject, THREAD, true);
1386 // prohibited package check assumes all classes loaded from archive call
1387 // restore_unshareable_info which calls ik->set_package()
1388 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1389 }
1390
1391 if (log_is_enabled(Info, class, load)) {
1392 ik()->print_loading_log(LogLevel::Info, loader_data, NULL, NULL);
1393 }
1394 // No 'else' here as logging levels are not mutually exclusive
1395
1396 if (log_is_enabled(Debug, class, load)) {
1397 ik()->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL);
1398 }
1399
1400 // For boot loader, ensure that GetSystemPackage knows that a class in this
1401 // package was loaded.
1402 if (class_loader.is_null()) {
1403 int path_index = ik->shared_classpath_index();
1404 ResourceMark rm;
1405 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1406 }
1407
1408 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1409 // Only dump the classes that can be stored into CDS archive
1410 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1411 ResourceMark rm(THREAD);
1412 classlist_file->print_cr("%s", ik->name()->as_C_string());
1413 classlist_file->flush();
1414 }
1415 }
1416
1417 // notify a class loaded from shared object
1418 ClassLoadingService::notify_class_loaded(ik(), true /* shared class */);
1419 }
1420
1421 ik->set_has_passed_fingerprint_check(false);
1422 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1423 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik());
1424 uint64_t cds_fp = ik->get_stored_fingerprint();
1425 if (aot_fp != 0 && aot_fp == cds_fp) {
1426 // This class matches with a class saved in an AOT library
1427 ik->set_has_passed_fingerprint_check(true);
1428 } else {
1429 ResourceMark rm;
1430 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1431 }
1432 }
1433 return ik;
1434 }
1435 #endif // INCLUDE_CDS
1436
1437 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1438 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1439
1440 if (class_loader.is_null()) {
1441 ResourceMark rm;
1442 PackageEntry* pkg_entry = NULL;
1443 bool search_only_bootloader_append = false;
1444 ClassLoaderData *loader_data = class_loader_data(class_loader);
1445
1446 // Find the package in the boot loader's package entry table.
1447 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1448 if (pkg_name != NULL) {
1449 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1450 }
1451
1452 // Prior to attempting to load the class, enforce the boot loader's
1453 // visibility boundaries.
1454 if (!Universe::is_module_initialized()) {
1455 // During bootstrapping, prior to module initialization, any
1456 // class attempting to be loaded must be checked against the
1457 // java.base packages in the boot loader's PackageEntryTable.
1458 // No class outside of java.base is allowed to be loaded during
1459 // this bootstrapping window.
1460 if (!DumpSharedSpaces) {
1461 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1462 // Class is either in the unnamed package or in
1463 // a named package within the unnamed module. Either
1464 // case is outside of java.base, do not attempt to
1465 // load the class post java.base definition. If
1466 // java.base has not been defined, let the class load
1467 // and its package will be checked later by
1468 // ModuleEntryTable::verify_javabase_packages.
1469 if (ModuleEntryTable::javabase_defined()) {
1470 return nh;
1471 }
1472 } else {
1473 // Check that the class' package is defined within java.base.
1474 ModuleEntry* mod_entry = pkg_entry->module();
1475 Symbol* mod_entry_name = mod_entry->name();
1476 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1477 return nh;
1478 }
1479 }
1480 }
1481 } else {
1482 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1483 // After the module system has been initialized, check if the class'
1484 // package is in a module defined to the boot loader.
1485 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1486 // Class is either in the unnamed package, in a named package
1487 // within a module not defined to the boot loader or in a
1488 // a named package within the unnamed module. In all cases,
1489 // limit visibility to search for the class only in the boot
1490 // loader's append path.
1491 search_only_bootloader_append = true;
1492 }
1493 }
1494
1495 // Prior to bootstrapping's module initialization, never load a class outside
1496 // of the boot loader's module path
1497 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1498 !search_only_bootloader_append,
1499 "Attempt to load a class outside of boot loader's module path");
1500
1501 // Search the shared system dictionary for classes preloaded into the
1502 // shared spaces.
1503 instanceKlassHandle k;
1504 {
1505 #if INCLUDE_CDS
1506 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1507 k = load_shared_class(class_name, class_loader, THREAD);
1508 #endif
1509 }
1510
1511 if (k.is_null()) {
1512 // Use VM class loader
1513 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1514 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_(nh));
1515 }
1516
1517 // find_or_define_instance_class may return a different InstanceKlass
1518 if (!k.is_null()) {
1519 instanceKlassHandle defined_k =
1520 find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1521 k = defined_k;
1522 }
1523 return k;
1524 } else {
1525 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1526 ResourceMark rm(THREAD);
1527
1528 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1529 JavaThread* jt = (JavaThread*) THREAD;
1530
1531 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1532 ClassLoader::perf_app_classload_selftime(),
1533 ClassLoader::perf_app_classload_count(),
1534 jt->get_thread_stat()->perf_recursion_counts_addr(),
1535 jt->get_thread_stat()->perf_timers_addr(),
1536 PerfClassTraceTime::CLASS_LOAD);
1537
1538 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1539 // Translate to external class name format, i.e., convert '/' chars to '.'
1540 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1541
1542 JavaValue result(T_OBJECT);
1543
1544 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1545
1546 // Call public unsynchronized loadClass(String) directly for all class loaders
1547 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1548 // acquire a class-name based lock rather than the class loader object lock.
1549 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1550 // so the call to loadClassInternal() was not required.
1551 //
1552 // UnsyncloadClass flag means both call loadClass(String) and do
1553 // not acquire the class loader lock even for class loaders that are
1554 // not parallelCapable. This was a risky transitional
1555 // flag for diagnostic purposes only. It is risky to call
1556 // custom class loaders without synchronization.
1557 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1558 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1559 // Do NOT assume this will be supported in future releases.
1560 //
1561 // Added MustCallLoadClassInternal in case we discover in the field
1562 // a customer that counts on this call
1563 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1564 JavaCalls::call_special(&result,
1565 class_loader,
1566 spec_klass,
1567 vmSymbols::loadClassInternal_name(),
1568 vmSymbols::string_class_signature(),
1569 string,
1570 CHECK_(nh));
1571 } else {
1572 JavaCalls::call_virtual(&result,
1573 class_loader,
1574 spec_klass,
1575 vmSymbols::loadClass_name(),
1576 vmSymbols::string_class_signature(),
1577 string,
1578 CHECK_(nh));
1579 }
1580
1581 assert(result.get_type() == T_OBJECT, "just checking");
1582 oop obj = (oop) result.get_jobject();
1583
1584 // Primitive classes return null since forName() can not be
1585 // used to obtain any of the Class objects representing primitives or void
1586 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1587 instanceKlassHandle k =
1588 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1589 // For user defined Java class loaders, check that the name returned is
1590 // the same as that requested. This check is done for the bootstrap
1591 // loader when parsing the class file.
1592 if (class_name == k->name()) {
1593 return k;
1594 }
1595 }
1596 // Class is not found or has the wrong name, return NULL
1597 return nh;
1598 }
1599 }
1600
1601 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1602
1603 ClassLoaderData* loader_data = k->class_loader_data();
1604 Handle class_loader_h(THREAD, loader_data->class_loader());
1605
1606 // for bootstrap and other parallel classloaders don't acquire lock,
1607 // use placeholder token
1608 // If a parallelCapable class loader calls define_instance_class instead of
1609 // find_or_define_instance_class to get here, we have a timing
1610 // hole with systemDictionary updates and check_constraints
1611 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1612 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1613 compute_loader_lock_object(class_loader_h, THREAD)),
1614 "define called without lock");
1615 }
1616
1617 // Check class-loading constraints. Throw exception if violation is detected.
1618 // Grabs and releases SystemDictionary_lock
1619 // The check_constraints/find_class call and update_dictionary sequence
1620 // must be "atomic" for a specific class/classloader pair so we never
1621 // define two different instanceKlasses for that class/classloader pair.
1622 // Existing classloaders will call define_instance_class with the
1623 // classloader lock held
1624 // Parallel classloaders will call find_or_define_instance_class
1625 // which will require a token to perform the define class
1626 Symbol* name_h = k->name();
1627 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1628 int d_index = dictionary()->hash_to_index(d_hash);
1629 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1630
1631 // Register class just loaded with class loader (placed in Vector)
1632 // Note we do this before updating the dictionary, as this can
1633 // fail with an OutOfMemoryError (if it does, we will *not* put this
1634 // class in the dictionary and will not update the class hierarchy).
1635 // JVMTI FollowReferences needs to find the classes this way.
1636 if (k->class_loader() != NULL) {
1637 methodHandle m(THREAD, Universe::loader_addClass_method());
1638 JavaValue result(T_VOID);
1639 JavaCallArguments args(class_loader_h);
1640 args.push_oop(Handle(THREAD, k->java_mirror()));
1641 JavaCalls::call(&result, m, &args, CHECK);
1642 }
1643
1644 // Add the new class. We need recompile lock during update of CHA.
1645 {
1646 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1647 int p_index = placeholders()->hash_to_index(p_hash);
1648
1649 MutexLocker mu_r(Compile_lock, THREAD);
1650
1651 // Add to class hierarchy, initialize vtables, and do possible
1652 // deoptimizations.
1653 add_to_hierarchy(k, CHECK); // No exception, but can block
1654
1655 // Add to systemDictionary - so other classes can see it.
1656 // Grabs and releases SystemDictionary_lock
1657 update_dictionary(d_index, d_hash, p_index, p_hash,
1658 k, class_loader_h, THREAD);
1659 }
1660 k->eager_initialize(THREAD);
1661
1662 // notify jvmti
1663 if (JvmtiExport::should_post_class_load()) {
1664 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1665 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1666
1667 }
1668 class_define_event(k);
1669 }
1670
1671 // Support parallel classloading
1672 // All parallel class loaders, including bootstrap classloader
1673 // lock a placeholder entry for this class/class_loader pair
1674 // to allow parallel defines of different classes for this class loader
1675 // With AllowParallelDefine flag==true, in case they do not synchronize around
1676 // FindLoadedClass/DefineClass, calls, we check for parallel
1677 // loading for them, wait if a defineClass is in progress
1678 // and return the initial requestor's results
1679 // This flag does not apply to the bootstrap classloader.
1680 // With AllowParallelDefine flag==false, call through to define_instance_class
1681 // which will throw LinkageError: duplicate class definition.
1682 // False is the requested default.
1683 // For better performance, the class loaders should synchronize
1684 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1685 // potentially waste time reading and parsing the bytestream.
1686 // Note: VM callers should ensure consistency of k/class_name,class_loader
1687 // Be careful when modifying this code: once you have run
1688 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1689 // you need to find_and_remove it before returning.
1690 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1691 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1692
1693 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1694 Symbol* name_h = k->name(); // passed in class_name may be null
1695 ClassLoaderData* loader_data = class_loader_data(class_loader);
1696
1697 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1698 int d_index = dictionary()->hash_to_index(d_hash);
1699
1700 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1701 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1702 int p_index = placeholders()->hash_to_index(p_hash);
1703 PlaceholderEntry* probe;
1704
1705 {
1706 MutexLocker mu(SystemDictionary_lock, THREAD);
1707 // First check if class already defined
1708 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1709 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1710 if (check != NULL) {
1711 return(instanceKlassHandle(THREAD, check));
1712 }
1713 }
1714
1715 // Acquire define token for this class/classloader
1716 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1717 // Wait if another thread defining in parallel
1718 // All threads wait - even those that will throw duplicate class: otherwise
1719 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1720 // if other thread has not finished updating dictionary
1721 while (probe->definer() != NULL) {
1722 SystemDictionary_lock->wait();
1723 }
1724 // Only special cases allow parallel defines and can use other thread's results
1725 // Other cases fall through, and may run into duplicate defines
1726 // caught by finding an entry in the SystemDictionary
1727 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1728 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1729 SystemDictionary_lock->notify_all();
1730 #ifdef ASSERT
1731 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1732 assert(check != NULL, "definer missed recording success");
1733 #endif
1734 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1735 } else {
1736 // This thread will define the class (even if earlier thread tried and had an error)
1737 probe->set_definer(THREAD);
1738 }
1739 }
1740
1741 define_instance_class(k, THREAD);
1742
1743 Handle linkage_exception = Handle(); // null handle
1744
1745 // definer must notify any waiting threads
1746 {
1747 MutexLocker mu(SystemDictionary_lock, THREAD);
1748 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1749 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1750 if (probe != NULL) {
1751 if (HAS_PENDING_EXCEPTION) {
1752 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1753 CLEAR_PENDING_EXCEPTION;
1754 } else {
1755 probe->set_instance_klass(k());
1756 }
1757 probe->set_definer(NULL);
1758 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1759 SystemDictionary_lock->notify_all();
1760 }
1761 }
1762
1763 // Can't throw exception while holding lock due to rank ordering
1764 if (linkage_exception() != NULL) {
1765 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1766 }
1767
1768 return k;
1769 }
1770 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1771 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1772 if (class_loader.is_null()) {
1773 return Handle(THREAD, _system_loader_lock_obj);
1774 } else {
1775 return class_loader;
1776 }
1777 }
1778
1779 // This method is added to check how often we have to wait to grab loader
1780 // lock. The results are being recorded in the performance counters defined in
1781 // ClassLoader::_sync_systemLoaderLockContentionRate and
1782 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1783 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1784 if (!UsePerfData) {
1785 return;
1786 }
1787
1788 assert(!loader_lock.is_null(), "NULL lock object");
1789
1790 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1791 == ObjectSynchronizer::owner_other) {
1792 // contention will likely happen, so increment the corresponding
1793 // contention counter.
1794 if (loader_lock() == _system_loader_lock_obj) {
1795 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1796 } else {
1797 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1798 }
1799 }
1800 }
1801
1802 // ----------------------------------------------------------------------------
1803 // Lookup
1804
1805 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1806 Symbol* class_name,
1807 ClassLoaderData* loader_data) {
1808 assert_locked_or_safepoint(SystemDictionary_lock);
1809 assert (index == dictionary()->index_for(class_name, loader_data),
1810 "incorrect index?");
1811
1812 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1813 return k;
1814 }
1815
1816
1817 // Basic find on classes in the midst of being loaded
1818 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1819 ClassLoaderData* loader_data) {
1820 assert_locked_or_safepoint(SystemDictionary_lock);
1821 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1822 int p_index = placeholders()->hash_to_index(p_hash);
1823 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1824 }
1825
1826
1827 // Used for assertions and verification only
1828 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1829 #ifndef ASSERT
1830 guarantee(VerifyBeforeGC ||
1831 VerifyDuringGC ||
1832 VerifyBeforeExit ||
1833 VerifyDuringStartup ||
1834 VerifyAfterGC, "too expensive");
1835 #endif
1836 assert_locked_or_safepoint(SystemDictionary_lock);
1837
1838 // First look in the loaded class array
1839 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1840 int d_index = dictionary()->hash_to_index(d_hash);
1841 return find_class(d_index, d_hash, class_name, loader_data);
1842 }
1843
1844
1845 // Get the next class in the dictionary.
1846 Klass* SystemDictionary::try_get_next_class() {
1847 return dictionary()->try_get_next_class();
1848 }
1849
1850
1851 // ----------------------------------------------------------------------------
1852 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1853 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1854 // before a new class is used.
1855
1856 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1857 assert(k.not_null(), "just checking");
1858 assert_locked_or_safepoint(Compile_lock);
1859
1860 // Link into hierachy. Make sure the vtables are initialized before linking into
1861 k->append_to_sibling_list(); // add to superklass/sibling list
1862 k->process_interfaces(THREAD); // handle all "implements" declarations
1863 k->set_init_state(InstanceKlass::loaded);
1864 // Now flush all code that depended on old class hierarchy.
1865 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1866 // Also, first reinitialize vtable because it may have gotten out of synch
1867 // while the new class wasn't connected to the class hierarchy.
1868 CodeCache::flush_dependents_on(k);
1869 }
1870
1871 // ----------------------------------------------------------------------------
1872 // GC support
1873
1874 // Following roots during mark-sweep is separated in two phases.
1875 //
1876 // The first phase follows preloaded classes and all other system
1877 // classes, since these will never get unloaded anyway.
1878 //
1879 // The second phase removes (unloads) unreachable classes from the
1880 // system dictionary and follows the remaining classes' contents.
1881
1882 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1883 roots_oops_do(blk, NULL);
1884 }
1885
1886 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1887 // Follow all system classes and temporary placeholders in dictionary
1888 dictionary()->always_strong_classes_do(closure);
1889
1890 // Placeholders. These represent classes we're actively loading.
1891 placeholders()->classes_do(closure);
1892 }
1893
1894 // Calculate a "good" systemdictionary size based
1895 // on predicted or current loaded classes count
1896 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1897 int newsize = _old_default_sdsize;
1898 if ((classcount > 0) && !DumpSharedSpaces) {
1899 int desiredsize = classcount/_average_depth_goal;
1900 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1901 newsize = _primelist[++_sdgeneration]) {
1902 if (desiredsize <= newsize) {
1903 break;
1904 }
1905 }
1906 }
1907 return newsize;
1908 }
1909
1910 #ifdef ASSERT
1911 class VerifySDReachableAndLiveClosure : public OopClosure {
1912 private:
1913 BoolObjectClosure* _is_alive;
1914
1915 template <class T> void do_oop_work(T* p) {
1916 oop obj = oopDesc::load_decode_heap_oop(p);
1917 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1918 }
1919
1920 public:
1921 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1922
1923 virtual void do_oop(oop* p) { do_oop_work(p); }
1924 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1925 };
1926 #endif
1927
1928 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1929 // Note: anonymous classes are not in the SD.
1930 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1931 bool clean_previous_versions) {
1932 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1933 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1934 clean_previous_versions);
1935 if (unloading_occurred) {
1936 dictionary()->do_unloading();
1937 constraints()->purge_loader_constraints();
1938 resolution_errors()->purge_resolution_errors();
1939 }
1940 // Oops referenced by the system dictionary may get unreachable independently
1941 // of the class loader (eg. cached protection domain oops). So we need to
1942 // explicitly unlink them here instead of in Dictionary::do_unloading.
1943 dictionary()->unlink(is_alive);
1944 #ifdef ASSERT
1945 VerifySDReachableAndLiveClosure cl(is_alive);
1946 dictionary()->oops_do(&cl);
1947 #endif
1948 return unloading_occurred;
1949 }
1950
1951 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1952 strong->do_oop(&_java_system_loader);
1953 strong->do_oop(&_system_loader_lock_obj);
1954 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1955
1956 // Adjust dictionary
1957 dictionary()->roots_oops_do(strong, weak);
1958
1959 // Visit extra methods
1960 invoke_method_table()->oops_do(strong);
1961 }
1962
1963 void SystemDictionary::oops_do(OopClosure* f) {
1964 f->do_oop(&_java_system_loader);
1965 f->do_oop(&_system_loader_lock_obj);
1966 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1967
1968 // Adjust dictionary
1969 dictionary()->oops_do(f);
1970
1971 // Visit extra methods
1972 invoke_method_table()->oops_do(f);
1973 }
1974
1975 // Extended Class redefinition support.
1976 // If one of these classes is replaced, we need to replace it in these places.
1977 // KlassClosure::do_klass should take the address of a class but we can
1978 // change that later.
1979 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1980 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1981 f->do_klass(_well_known_klasses[k]);
1982 }
1983
1984 {
1985 for (int i = 0; i < T_VOID+1; i++) {
1986 if (_box_klasses[i] != NULL) {
1987 assert(i >= T_BOOLEAN, "checking");
1988 f->do_klass(_box_klasses[i]);
1989 }
1990 }
1991 }
1992
1993 FilteredFieldsMap::classes_do(f);
1994 }
1995
1996 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1997 f->do_klass(_abstract_ownable_synchronizer_klass);
1998 }
1999
2000 // Just the classes from defining class loaders
2001 // Don't iterate over placeholders
2002 void SystemDictionary::classes_do(void f(Klass*)) {
2003 dictionary()->classes_do(f);
2004 }
2005
2006 // Added for initialize_itable_for_klass
2007 // Just the classes from defining class loaders
2008 // Don't iterate over placeholders
2009 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
2010 dictionary()->classes_do(f, CHECK);
2011 }
2012
2013 // All classes, and their class loaders
2014 // Don't iterate over placeholders
2015 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
2016 dictionary()->classes_do(f);
2017 }
2018
2019 void SystemDictionary::placeholders_do(void f(Symbol*)) {
2020 placeholders()->entries_do(f);
2021 }
2022
2023 void SystemDictionary::methods_do(void f(Method*)) {
2024 dictionary()->methods_do(f);
2025 invoke_method_table()->methods_do(f);
2026 }
2027
2028 void SystemDictionary::remove_classes_in_error_state() {
2029 dictionary()->remove_classes_in_error_state();
2030 }
2031
2032 // ----------------------------------------------------------------------------
2033 // Lazily load klasses
2034
2035 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2036 // if multiple threads calling this function, only one thread will load
2037 // the class. The other threads will find the loaded version once the
2038 // class is loaded.
2039 Klass* aos = _abstract_ownable_synchronizer_klass;
2040 if (aos == NULL) {
2041 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2042 // Force a fence to prevent any read before the write completes
2043 OrderAccess::fence();
2044 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2045 }
2046 }
2047
2048 // ----------------------------------------------------------------------------
2049 // Initialization
2050
2051 void SystemDictionary::initialize(TRAPS) {
2052 // Allocate arrays
2053 assert(dictionary() == NULL,
2054 "SystemDictionary should only be initialized once");
2055 _sdgeneration = 0;
2056 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2057 _placeholders = new PlaceholderTable(_nof_buckets);
2058 _number_of_modifications = 0;
2059 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2060 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2061 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2062
2063 // Allocate private object used as system class loader lock
2064 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2065 // Initialize basic classes
2066 initialize_preloaded_classes(CHECK);
2067 }
2068
2069 // Compact table of directions on the initialization of klasses:
2070 static const short wk_init_info[] = {
2071 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2072 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2073 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2074 | (int)SystemDictionary::option ),
2075 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2076 #undef WK_KLASS_INIT_INFO
2077 0
2078 };
2079
2080 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2081 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2082 int info = wk_init_info[id - FIRST_WKID];
2083 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2084 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2085 InstanceKlass** klassp = &_well_known_klasses[id];
2086
2087 bool must_load;
2088 #if INCLUDE_JVMCI
2089 if (EnableJVMCI) {
2090 // If JVMCI is enabled we require its classes to be found.
2091 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2092 } else
2093 #endif
2094 {
2095 must_load = (init_opt < SystemDictionary::Opt);
2096 }
2097
2098 if ((*klassp) == NULL) {
2099 Klass* k;
2100 if (must_load) {
2101 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2102 } else {
2103 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2104 }
2105 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2106 }
2107 return ((*klassp) != NULL);
2108 }
2109
2110 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2111 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2112 for (int id = (int)start_id; id < (int)limit_id; id++) {
2113 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2114 int info = wk_init_info[id - FIRST_WKID];
2115 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2116 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2117
2118 initialize_wk_klass((WKID)id, opt, CHECK);
2119 }
2120
2121 // move the starting value forward to the limit:
2122 start_id = limit_id;
2123 }
2124
2125 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2126 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2127
2128 // Create the ModuleEntry for java.base. This call needs to be done here,
2129 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2130 ClassLoader::classLoader_init2(CHECK);
2131
2132 // Preload commonly used klasses
2133 WKID scan = FIRST_WKID;
2134 // first do Object, then String, Class
2135 if (UseSharedSpaces) {
2136 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2137 // Initialize the constant pool for the Object_class
2138 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
2139 ik->constants()->restore_unshareable_info(CHECK);
2140 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2141 } else {
2142 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2143 }
2144
2145 // Calculate offsets for String and Class classes since they are loaded and
2146 // can be used after this point.
2147 java_lang_String::compute_offsets();
2148 java_lang_Class::compute_offsets();
2149
2150 // Fixup mirrors for classes loaded before java.lang.Class.
2151 // These calls iterate over the objects currently in the perm gen
2152 // so calling them at this point is matters (not before when there
2153 // are fewer objects and not later after there are more objects
2154 // in the perm gen.
2155 Universe::initialize_basic_type_mirrors(CHECK);
2156 Universe::fixup_mirrors(CHECK);
2157
2158 // do a bunch more:
2159 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2160
2161 // Preload ref klasses and set reference types
2162 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2163 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2164
2165 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2166 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2167 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2168 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2169 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2170
2171 // JSR 292 classes
2172 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2173 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2174 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2175 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2176 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2177
2178 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2179 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2180 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2181 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2182 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2183 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2184 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2185 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2186 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2187 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2188
2189 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2190 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2191 _has_loadClassInternal = (method != NULL);
2192 }
2193 { // Compute whether we should use checkPackageAccess or NOT
2194 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2195 _has_checkPackageAccess = (method != NULL);
2196 }
2197 }
2198
2199 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2200 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2201 BasicType SystemDictionary::box_klass_type(Klass* k) {
2202 assert(k != NULL, "");
2203 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2204 if (_box_klasses[i] == k)
2205 return (BasicType)i;
2206 }
2207 return T_OBJECT;
2208 }
2209
2210 // Constraints on class loaders. The details of the algorithm can be
2211 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2212 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2213 // that the system dictionary needs to maintain a set of contraints that
2214 // must be satisfied by all classes in the dictionary.
2215 // if defining is true, then LinkageError if already in systemDictionary
2216 // if initiating loader, then ok if InstanceKlass matches existing entry
2217
2218 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2219 instanceKlassHandle k,
2220 Handle class_loader, bool defining,
2221 TRAPS) {
2222 const char *linkage_error1 = NULL;
2223 const char *linkage_error2 = NULL;
2224 {
2225 Symbol* name = k->name();
2226 ClassLoaderData *loader_data = class_loader_data(class_loader);
2227
2228 MutexLocker mu(SystemDictionary_lock, THREAD);
2229
2230 Klass* check = find_class(d_index, d_hash, name, loader_data);
2231 if (check != (Klass*)NULL) {
2232 // if different InstanceKlass - duplicate class definition,
2233 // else - ok, class loaded by a different thread in parallel,
2234 // we should only have found it if it was done loading and ok to use
2235 // system dictionary only holds instance classes, placeholders
2236 // also holds array classes
2237
2238 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2239 if ((defining == true) || (k() != check)) {
2240 linkage_error1 = "loader (instance of ";
2241 linkage_error2 = "): attempted duplicate class definition for name: \"";
2242 } else {
2243 return;
2244 }
2245 }
2246
2247 #ifdef ASSERT
2248 Symbol* ph_check = find_placeholder(name, loader_data);
2249 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2250 #endif
2251
2252 if (linkage_error1 == NULL) {
2253 if (constraints()->check_or_update(k, class_loader, name) == false) {
2254 linkage_error1 = "loader constraint violation: loader (instance of ";
2255 linkage_error2 = ") previously initiated loading for a different type with name \"";
2256 }
2257 }
2258 }
2259
2260 // Throw error now if needed (cannot throw while holding
2261 // SystemDictionary_lock because of rank ordering)
2262
2263 if (linkage_error1) {
2264 ResourceMark rm(THREAD);
2265 const char* class_loader_name = loader_name(class_loader());
2266 char* type_name = k->name()->as_C_string();
2267 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2268 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2269 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2270 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2271 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2272 }
2273 }
2274
2275
2276 // Update system dictionary - done after check_constraint and add_to_hierachy
2277 // have been called.
2278 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2279 int p_index, unsigned int p_hash,
2280 instanceKlassHandle k,
2281 Handle class_loader,
2282 TRAPS) {
2283 // Compile_lock prevents systemDictionary updates during compilations
2284 assert_locked_or_safepoint(Compile_lock);
2285 Symbol* name = k->name();
2286 ClassLoaderData *loader_data = class_loader_data(class_loader);
2287
2288 {
2289 MutexLocker mu1(SystemDictionary_lock, THREAD);
2290
2291 // See whether biased locking is enabled and if so set it for this
2292 // klass.
2293 // Note that this must be done past the last potential blocking
2294 // point / safepoint. We enable biased locking lazily using a
2295 // VM_Operation to iterate the SystemDictionary and installing the
2296 // biasable mark word into each InstanceKlass's prototype header.
2297 // To avoid race conditions where we accidentally miss enabling the
2298 // optimization for one class in the process of being added to the
2299 // dictionary, we must not safepoint after the test of
2300 // BiasedLocking::enabled().
2301 if (UseBiasedLocking && BiasedLocking::enabled()) {
2302 // Set biased locking bit for all loaded classes; it will be
2303 // cleared if revocation occurs too often for this type
2304 // NOTE that we must only do this when the class is initally
2305 // defined, not each time it is referenced from a new class loader
2306 if (k->class_loader() == class_loader()) {
2307 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2308 }
2309 }
2310
2311 // Make a new system dictionary entry.
2312 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2313 if (sd_check == NULL) {
2314 dictionary()->add_klass(name, loader_data, k);
2315 notice_modification();
2316 }
2317 #ifdef ASSERT
2318 sd_check = find_class(d_index, d_hash, name, loader_data);
2319 assert (sd_check != NULL, "should have entry in system dictionary");
2320 // Note: there may be a placeholder entry: for circularity testing
2321 // or for parallel defines
2322 #endif
2323 SystemDictionary_lock->notify_all();
2324 }
2325 }
2326
2327
2328 // Try to find a class name using the loader constraints. The
2329 // loader constraints might know about a class that isn't fully loaded
2330 // yet and these will be ignored.
2331 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2332 Symbol* class_name, Handle class_loader, TRAPS) {
2333
2334 // First see if it has been loaded directly.
2335 // Force the protection domain to be null. (This removes protection checks.)
2336 Handle no_protection_domain;
2337 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2338 no_protection_domain, CHECK_NULL);
2339 if (klass != NULL)
2340 return klass;
2341
2342 // Now look to see if it has been loaded elsewhere, and is subject to
2343 // a loader constraint that would require this loader to return the
2344 // klass that is already loaded.
2345 if (FieldType::is_array(class_name)) {
2346 // For array classes, their Klass*s are not kept in the
2347 // constraint table. The element Klass*s are.
2348 FieldArrayInfo fd;
2349 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2350 if (t != T_OBJECT) {
2351 klass = Universe::typeArrayKlassObj(t);
2352 } else {
2353 MutexLocker mu(SystemDictionary_lock, THREAD);
2354 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2355 }
2356 // If element class already loaded, allocate array klass
2357 if (klass != NULL) {
2358 klass = klass->array_klass_or_null(fd.dimension());
2359 }
2360 } else {
2361 MutexLocker mu(SystemDictionary_lock, THREAD);
2362 // Non-array classes are easy: simply check the constraint table.
2363 klass = constraints()->find_constrained_klass(class_name, class_loader);
2364 }
2365
2366 return klass;
2367 }
2368
2369
2370 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2371 Handle class_loader1,
2372 Handle class_loader2,
2373 Thread* THREAD) {
2374 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2375 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2376
2377 Symbol* constraint_name = NULL;
2378 if (!FieldType::is_array(class_name)) {
2379 constraint_name = class_name;
2380 } else {
2381 // For array classes, their Klass*s are not kept in the
2382 // constraint table. The element classes are.
2383 FieldArrayInfo fd;
2384 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2385 // primitive types always pass
2386 if (t != T_OBJECT) {
2387 return true;
2388 } else {
2389 constraint_name = fd.object_key();
2390 }
2391 }
2392 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2393 int d_index1 = dictionary()->hash_to_index(d_hash1);
2394
2395 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2396 int d_index2 = dictionary()->hash_to_index(d_hash2);
2397 {
2398 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2399
2400 // Better never do a GC while we're holding these oops
2401 NoSafepointVerifier nosafepoint;
2402
2403 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2404 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2405 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2406 klass2, class_loader2);
2407 }
2408 }
2409
2410 // Add entry to resolution error table to record the error when the first
2411 // attempt to resolve a reference to a class has failed.
2412 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2413 Symbol* error, 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 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2419 }
2420 }
2421
2422 // Delete a resolution error for RedefineClasses for a constant pool is going away
2423 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2424 resolution_errors()->delete_entry(pool);
2425 }
2426
2427 // Lookup resolution error table. Returns error if found, otherwise NULL.
2428 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2429 Symbol** message) {
2430 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2431 int index = resolution_errors()->hash_to_index(hash);
2432 {
2433 MutexLocker ml(SystemDictionary_lock, Thread::current());
2434 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2435 if (entry != NULL) {
2436 *message = entry->message();
2437 return entry->error();
2438 } else {
2439 return NULL;
2440 }
2441 }
2442 }
2443
2444
2445 // Signature constraints ensure that callers and callees agree about
2446 // the meaning of type names in their signatures. This routine is the
2447 // intake for constraints. It collects them from several places:
2448 //
2449 // * LinkResolver::resolve_method (if check_access is true) requires
2450 // that the resolving class (the caller) and the defining class of
2451 // the resolved method (the callee) agree on each type in the
2452 // method's signature.
2453 //
2454 // * LinkResolver::resolve_interface_method performs exactly the same
2455 // checks.
2456 //
2457 // * LinkResolver::resolve_field requires that the constant pool
2458 // attempting to link to a field agree with the field's defining
2459 // class about the type of the field signature.
2460 //
2461 // * klassVtable::initialize_vtable requires that, when a class
2462 // overrides a vtable entry allocated by a superclass, that the
2463 // overriding method (i.e., the callee) agree with the superclass
2464 // on each type in the method's signature.
2465 //
2466 // * klassItable::initialize_itable requires that, when a class fills
2467 // in its itables, for each non-abstract method installed in an
2468 // itable, the method (i.e., the callee) agree with the interface
2469 // on each type in the method's signature.
2470 //
2471 // All those methods have a boolean (check_access, checkconstraints)
2472 // which turns off the checks. This is used from specialized contexts
2473 // such as bootstrapping, dumping, and debugging.
2474 //
2475 // No direct constraint is placed between the class and its
2476 // supertypes. Constraints are only placed along linked relations
2477 // between callers and callees. When a method overrides or implements
2478 // an abstract method in a supertype (superclass or interface), the
2479 // constraints are placed as if the supertype were the caller to the
2480 // overriding method. (This works well, since callers to the
2481 // supertype have already established agreement between themselves and
2482 // the supertype.) As a result of all this, a class can disagree with
2483 // its supertype about the meaning of a type name, as long as that
2484 // class neither calls a relevant method of the supertype, nor is
2485 // called (perhaps via an override) from the supertype.
2486 //
2487 //
2488 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2489 //
2490 // Make sure all class components (including arrays) in the given
2491 // signature will be resolved to the same class in both loaders.
2492 // Returns the name of the type that failed a loader constraint check, or
2493 // NULL if no constraint failed. No exception except OOME is thrown.
2494 // Arrays are not added to the loader constraint table, their elements are.
2495 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2496 Handle loader1, Handle loader2,
2497 bool is_method, TRAPS) {
2498 // Nothing to do if loaders are the same.
2499 if (loader1() == loader2()) {
2500 return NULL;
2501 }
2502
2503 SignatureStream sig_strm(signature, is_method);
2504 while (!sig_strm.is_done()) {
2505 if (sig_strm.is_object()) {
2506 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2507 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2508 return sig;
2509 }
2510 }
2511 sig_strm.next();
2512 }
2513 return NULL;
2514 }
2515
2516
2517 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2518 Symbol* signature,
2519 TRAPS) {
2520 methodHandle empty;
2521 assert(MethodHandles::is_signature_polymorphic(iid) &&
2522 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2523 iid != vmIntrinsics::_invokeGeneric,
2524 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2525
2526 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2527 int index = invoke_method_table()->hash_to_index(hash);
2528 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2529 methodHandle m;
2530 if (spe == NULL || spe->method() == NULL) {
2531 spe = NULL;
2532 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2533 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2534 if (!Arguments::is_interpreter_only()) {
2535 // Generate a compiled form of the MH intrinsic.
2536 AdapterHandlerLibrary::create_native_wrapper(m);
2537 // Check if have the compiled code.
2538 if (!m->has_compiled_code()) {
2539 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2540 "Out of space in CodeCache for method handle intrinsic", empty);
2541 }
2542 }
2543 // Now grab the lock. We might have to throw away the new method,
2544 // if a racing thread has managed to install one at the same time.
2545 {
2546 MutexLocker ml(SystemDictionary_lock, THREAD);
2547 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2548 if (spe == NULL)
2549 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2550 if (spe->method() == NULL)
2551 spe->set_method(m());
2552 }
2553 }
2554
2555 assert(spe != NULL && spe->method() != NULL, "");
2556 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2557 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2558 "MH intrinsic invariant");
2559 return spe->method();
2560 }
2561
2562 // Helper for unpacking the return value from linkMethod and linkCallSite.
2563 static methodHandle unpack_method_and_appendix(Handle mname,
2564 KlassHandle accessing_klass,
2565 objArrayHandle appendix_box,
2566 Handle* appendix_result,
2567 TRAPS) {
2568 methodHandle empty;
2569 if (mname.not_null()) {
2570 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2571 if (vmtarget != NULL && vmtarget->is_method()) {
2572 Method* m = (Method*)vmtarget;
2573 oop appendix = appendix_box->obj_at(0);
2574 if (TraceMethodHandles) {
2575 #ifndef PRODUCT
2576 ttyLocker ttyl;
2577 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2578 m->print();
2579 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2580 tty->cr();
2581 #endif //PRODUCT
2582 }
2583 (*appendix_result) = Handle(THREAD, appendix);
2584 // the target is stored in the cpCache and if a reference to this
2585 // MethodName is dropped we need a way to make sure the
2586 // class_loader containing this method is kept alive.
2587 // FIXME: the appendix might also preserve this dependency.
2588 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2589 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2590 return methodHandle(THREAD, m);
2591 }
2592 }
2593 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2594 return empty;
2595 }
2596
2597 methodHandle SystemDictionary::find_method_handle_invoker(KlassHandle klass,
2598 Symbol* name,
2599 Symbol* signature,
2600 KlassHandle accessing_klass,
2601 Handle *appendix_result,
2602 Handle *method_type_result,
2603 TRAPS) {
2604 methodHandle empty;
2605 assert(THREAD->can_call_java() ,"");
2606 Handle method_type =
2607 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2608
2609 int ref_kind = JVM_REF_invokeVirtual;
2610 Handle name_str = StringTable::intern(name, CHECK_(empty));
2611 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2612 assert(appendix_box->obj_at(0) == NULL, "");
2613
2614 // This should not happen. JDK code should take care of that.
2615 if (accessing_klass.is_null() || method_type.is_null()) {
2616 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2617 }
2618
2619 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2620 JavaCallArguments args;
2621 args.push_oop(accessing_klass()->java_mirror());
2622 args.push_int(ref_kind);
2623 args.push_oop(klass()->java_mirror());
2624 args.push_oop(name_str());
2625 args.push_oop(method_type());
2626 args.push_oop(appendix_box());
2627 JavaValue result(T_OBJECT);
2628 JavaCalls::call_static(&result,
2629 SystemDictionary::MethodHandleNatives_klass(),
2630 vmSymbols::linkMethod_name(),
2631 vmSymbols::linkMethod_signature(),
2632 &args, CHECK_(empty));
2633 Handle mname(THREAD, (oop) result.get_jobject());
2634 (*method_type_result) = method_type;
2635 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2636 }
2637
2638 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2639 // We must ensure that all class loaders everywhere will reach this class, for any client.
2640 // This is a safe bet for public classes in java.lang, such as Object and String.
2641 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2642 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2643 static bool is_always_visible_class(oop mirror) {
2644 Klass* klass = java_lang_Class::as_Klass(mirror);
2645 if (klass->is_objArray_klass()) {
2646 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2647 }
2648 if (klass->is_typeArray_klass()) {
2649 return true; // primitive array
2650 }
2651 assert(klass->is_instance_klass(), "%s", klass->external_name());
2652 return klass->is_public() &&
2653 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2654 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2655 }
2656
2657 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2658 // signature, as interpreted relative to the given class loader.
2659 // Because of class loader constraints, all method handle usage must be
2660 // consistent with this loader.
2661 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2662 KlassHandle accessing_klass,
2663 TRAPS) {
2664 Handle empty;
2665 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2666 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2667 int index = invoke_method_table()->hash_to_index(hash);
2668 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2669 if (spe != NULL && spe->method_type() != NULL) {
2670 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2671 return Handle(THREAD, spe->method_type());
2672 } else if (!THREAD->can_call_java()) {
2673 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2674 return Handle(); // do not attempt from within compiler, unless it was cached
2675 }
2676
2677 Handle class_loader, protection_domain;
2678 if (accessing_klass.not_null()) {
2679 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2680 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2681 }
2682 bool can_be_cached = true;
2683 int npts = ArgumentCount(signature).size();
2684 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2685 int arg = 0;
2686 Handle rt; // the return type from the signature
2687 ResourceMark rm(THREAD);
2688 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2689 oop mirror = NULL;
2690 if (can_be_cached) {
2691 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2692 mirror = ss.as_java_mirror(Handle(), Handle(),
2693 SignatureStream::ReturnNull, CHECK_(empty));
2694 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2695 // Fall back to accessing_klass context.
2696 can_be_cached = false;
2697 }
2698 }
2699 if (!can_be_cached) {
2700 // Resolve, throwing a real error if it doesn't work.
2701 mirror = ss.as_java_mirror(class_loader, protection_domain,
2702 SignatureStream::NCDFError, CHECK_(empty));
2703 }
2704 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2705 if (ss.at_return_type())
2706 rt = Handle(THREAD, mirror);
2707 else
2708 pts->obj_at_put(arg++, mirror);
2709
2710 // Check accessibility.
2711 if (ss.is_object() && accessing_klass.not_null()) {
2712 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2713 mirror = NULL; // safety
2714 // Emulate ConstantPool::verify_constant_pool_resolve.
2715 if (sel_klass->is_objArray_klass())
2716 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2717 if (sel_klass->is_instance_klass()) {
2718 KlassHandle sel_kh(THREAD, sel_klass);
2719 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2720 }
2721 }
2722 }
2723 assert(arg == npts, "");
2724
2725 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2726 JavaCallArguments args(Handle(THREAD, rt()));
2727 args.push_oop(pts());
2728 JavaValue result(T_OBJECT);
2729 JavaCalls::call_static(&result,
2730 SystemDictionary::MethodHandleNatives_klass(),
2731 vmSymbols::findMethodHandleType_name(),
2732 vmSymbols::findMethodHandleType_signature(),
2733 &args, CHECK_(empty));
2734 Handle method_type(THREAD, (oop) result.get_jobject());
2735
2736 if (can_be_cached) {
2737 // We can cache this MethodType inside the JVM.
2738 MutexLocker ml(SystemDictionary_lock, THREAD);
2739 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2740 if (spe == NULL)
2741 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2742 if (spe->method_type() == NULL) {
2743 spe->set_method_type(method_type());
2744 }
2745 }
2746
2747 // report back to the caller with the MethodType
2748 return method_type;
2749 }
2750
2751 // Ask Java code to find or construct a method handle constant.
2752 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2753 int ref_kind, //e.g., JVM_REF_invokeVirtual
2754 KlassHandle callee,
2755 Symbol* name_sym,
2756 Symbol* signature,
2757 TRAPS) {
2758 Handle empty;
2759 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2760 Handle type;
2761 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2762 type = find_method_handle_type(signature, caller, CHECK_(empty));
2763 } else if (caller.is_null()) {
2764 // This should not happen. JDK code should take care of that.
2765 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2766 } else {
2767 ResourceMark rm(THREAD);
2768 SignatureStream ss(signature, false);
2769 if (!ss.is_done()) {
2770 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2771 SignatureStream::NCDFError, CHECK_(empty));
2772 type = Handle(THREAD, mirror);
2773 ss.next();
2774 if (!ss.is_done()) type = Handle(); // error!
2775 }
2776 }
2777 if (type.is_null()) {
2778 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2779 }
2780
2781 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2782 JavaCallArguments args;
2783 args.push_oop(caller->java_mirror()); // the referring class
2784 args.push_int(ref_kind);
2785 args.push_oop(callee->java_mirror()); // the target class
2786 args.push_oop(name());
2787 args.push_oop(type());
2788 JavaValue result(T_OBJECT);
2789 JavaCalls::call_static(&result,
2790 SystemDictionary::MethodHandleNatives_klass(),
2791 vmSymbols::linkMethodHandleConstant_name(),
2792 vmSymbols::linkMethodHandleConstant_signature(),
2793 &args, CHECK_(empty));
2794 return Handle(THREAD, (oop) result.get_jobject());
2795 }
2796
2797 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2798 // name and signature, as interpreted relative to the given class loader.
2799 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2800 Handle bootstrap_specifier,
2801 Symbol* name,
2802 Symbol* type,
2803 Handle *appendix_result,
2804 Handle *method_type_result,
2805 TRAPS) {
2806 methodHandle empty;
2807 Handle bsm, info;
2808 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2809 bsm = bootstrap_specifier;
2810 } else {
2811 assert(bootstrap_specifier->is_objArray(), "");
2812 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2813 int len = args->length();
2814 assert(len >= 1, "");
2815 bsm = Handle(THREAD, args->obj_at(0));
2816 if (len > 1) {
2817 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2818 for (int i = 1; i < len; i++)
2819 args1->obj_at_put(i-1, args->obj_at(i));
2820 info = Handle(THREAD, args1);
2821 }
2822 }
2823 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2824 "caller must supply a valid BSM");
2825
2826 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2827 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2828
2829 // This should not happen. JDK code should take care of that.
2830 if (caller.is_null() || method_type.is_null()) {
2831 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2832 }
2833
2834 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2835 assert(appendix_box->obj_at(0) == NULL, "");
2836
2837 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2838 JavaCallArguments args;
2839 args.push_oop(caller->java_mirror());
2840 args.push_oop(bsm());
2841 args.push_oop(method_name());
2842 args.push_oop(method_type());
2843 args.push_oop(info());
2844 args.push_oop(appendix_box);
2845 JavaValue result(T_OBJECT);
2846 JavaCalls::call_static(&result,
2847 SystemDictionary::MethodHandleNatives_klass(),
2848 vmSymbols::linkCallSite_name(),
2849 vmSymbols::linkCallSite_signature(),
2850 &args, CHECK_(empty));
2851 Handle mname(THREAD, (oop) result.get_jobject());
2852 (*method_type_result) = method_type;
2853 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2854 }
2855
2856 // Since the identity hash code for symbols changes when the symbols are
2857 // moved from the regular perm gen (hash in the mark word) to the shared
2858 // spaces (hash is the address), the classes loaded into the dictionary
2859 // may be in the wrong buckets.
2860
2861 void SystemDictionary::reorder_dictionary() {
2862 dictionary()->reorder_dictionary();
2863 }
2864
2865
2866 void SystemDictionary::copy_buckets(char** top, char* end) {
2867 dictionary()->copy_buckets(top, end);
2868 }
2869
2870
2871 void SystemDictionary::copy_table(char** top, char* end) {
2872 dictionary()->copy_table(top, end);
2873 }
2874
2875
2876 void SystemDictionary::reverse() {
2877 dictionary()->reverse();
2878 }
2879
2880 int SystemDictionary::number_of_classes() {
2881 return dictionary()->number_of_entries();
2882 }
2883
2884
2885 // ----------------------------------------------------------------------------
2886 void SystemDictionary::print_shared(bool details) {
2887 shared_dictionary()->print(details);
2888 }
2889
2890 void SystemDictionary::print(bool details) {
2891 dictionary()->print(details);
2892
2893 // Placeholders
2894 GCMutexLocker mu(SystemDictionary_lock);
2895 placeholders()->print();
2896
2897 // loader constraints - print under SD_lock
2898 constraints()->print();
2899 }
2900
2901
2902 void SystemDictionary::verify() {
2903 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2904 guarantee(constraints() != NULL,
2905 "Verify of loader constraints failed");
2906 guarantee(dictionary()->number_of_entries() >= 0 &&
2907 placeholders()->number_of_entries() >= 0,
2908 "Verify of system dictionary failed");
2909
2910 // Verify dictionary
2911 dictionary()->verify();
2912
2913 GCMutexLocker mu(SystemDictionary_lock);
2914 placeholders()->verify();
2915
2916 // Verify constraint table
2917 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2918 constraints()->verify(dictionary(), placeholders());
2919 }
2920
2921 // caller needs ResourceMark
2922 const char* SystemDictionary::loader_name(const oop loader) {
2923 return ((loader) == NULL ? "<bootloader>" :
2924 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2925 }
2926
2927 // caller needs ResourceMark
2928 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2929 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2930 InstanceKlass::cast((loader_data->class_loader())->klass())->name()->as_C_string());
2931 }