1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/resolutionErrors.hpp"
39 #include "classfile/stringTable.hpp"
40 #include "classfile/systemDictionary.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "code/codeCache.hpp"
43 #include "compiler/compileBroker.hpp"
44 #include "gc/shared/gcLocker.hpp"
45 #include "interpreter/bytecodeStream.hpp"
46 #include "interpreter/interpreter.hpp"
47 #include "memory/filemap.hpp"
48 #include "memory/oopFactory.hpp"
49 #include "memory/resourceArea.hpp"
50 #include "oops/instanceKlass.hpp"
51 #include "oops/instanceRefKlass.hpp"
52 #include "oops/klass.inline.hpp"
53 #include "oops/methodData.hpp"
54 #include "oops/objArrayKlass.hpp"
55 #include "oops/objArrayOop.inline.hpp"
56 #include "oops/oop.inline.hpp"
57 #include "oops/symbol.hpp"
58 #include "oops/typeArrayKlass.hpp"
59 #include "prims/jvmtiEnvBase.hpp"
60 #include "prims/methodHandles.hpp"
61 #include "runtime/arguments.hpp"
62 #include "runtime/biasedLocking.hpp"
63 #include "runtime/fieldType.hpp"
64 #include "runtime/handles.inline.hpp"
65 #include "runtime/java.hpp"
66 #include "runtime/javaCalls.hpp"
67 #include "runtime/mutexLocker.hpp"
68 #include "runtime/orderAccess.inline.hpp"
69 #include "runtime/signature.hpp"
70 #include "services/classLoadingService.hpp"
71 #include "services/threadService.hpp"
72 #include "trace/traceMacros.hpp"
73 #include "utilities/macros.hpp"
74 #include "utilities/ticks.hpp"
75 #if INCLUDE_CDS
76 #include "classfile/sharedClassUtil.hpp"
77 #include "classfile/systemDictionaryShared.hpp"
78 #endif
79 #if INCLUDE_JVMCI
80 #include "jvmci/jvmciRuntime.hpp"
81 #endif
82 #if INCLUDE_TRACE
83 #include "trace/tracing.hpp"
84 #endif
85
86 Dictionary* SystemDictionary::_dictionary = NULL;
87 PlaceholderTable* SystemDictionary::_placeholders = NULL;
88 Dictionary* SystemDictionary::_shared_dictionary = NULL;
89 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
90 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
91 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
92
93
94 int SystemDictionary::_number_of_modifications = 0;
95 int SystemDictionary::_sdgeneration = 0;
96 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
97 20201,40423,99991};
98
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107
108 bool SystemDictionary::_has_loadClassInternal = false;
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114
115 // ----------------------------------------------------------------------------
116 // Java-level SystemLoader
117
118 oop SystemDictionary::java_system_loader() {
119 return _java_system_loader;
120 }
121
122 void SystemDictionary::compute_java_system_loader(TRAPS) {
123 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(oop class_loader) {
164 if (class_loader == NULL) {
165 return false;
166 }
167 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
168 class_loader == _java_system_loader);
169 }
170
171 // Returns true if the passed class loader is the platform class loader.
172 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
173 if (class_loader == NULL) {
174 return false;
175 }
176 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
177 }
178
179 // ----------------------------------------------------------------------------
180 // Resolving of classes
181
182 // Forwards to resolve_or_null
183
184 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
185 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
186 if (HAS_PENDING_EXCEPTION || klass == NULL) {
187 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 static void post_class_load_event(const Ticks& start_time,
626 instanceKlassHandle k,
627 const ClassLoaderData* init_cld) {
628 #if INCLUDE_TRACE
629 EventClassLoad event(UNTIMED);
630 if (event.should_commit()) {
631 event.set_starttime(start_time);
632 event.set_loadedClass(k());
633 event.set_definingClassLoader(k->class_loader_data());
634 event.set_initiatingClassLoader(init_cld);
635 event.commit();
636 }
637 #endif // INCLUDE_TRACE
638 }
639
640 static void class_define_event(instanceKlassHandle k,
641 const ClassLoaderData* def_cld) {
642 #if INCLUDE_TRACE
643 EventClassDefine event;
644 if (event.should_commit()) {
645 event.set_definedClass(k());
646 event.set_definingClassLoader(def_cld);
647 event.commit();
648 }
649 #endif // INCLUDE_TRACE
650 }
651
652 // Be careful when modifying this code: once you have run
653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
654 // you need to find_and_remove it before returning.
655 // So be careful to not exit with a CHECK_ macro betweeen these calls.
656 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
657 Handle class_loader,
658 Handle protection_domain,
659 TRAPS) {
660 assert(name != NULL && !FieldType::is_array(name) &&
661 !FieldType::is_obj(name), "invalid class name");
662
663 Ticks class_load_start_time = Ticks::now();
664
665 HandleMark hm(THREAD);
666
667 // Fix for 4474172; see evaluation for more details
668 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
669 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
670
671 // Do lookup to see if class already exist and the protection domain
672 // has the right access
673 // This call uses find which checks protection domain already matches
674 // All subsequent calls use find_class, and set has_loaded_class so that
675 // before we return a result we call out to java to check for valid protection domain
676 // to allow returning the Klass* and add it to the pd_set if it is valid
677 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
678 int d_index = dictionary()->hash_to_index(d_hash);
679 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
680 protection_domain, THREAD);
681 if (probe != NULL) return probe;
682
683
684 // Non-bootstrap class loaders will call out to class loader and
685 // define via jvm/jni_DefineClass which will acquire the
686 // class loader object lock to protect against multiple threads
687 // defining the class in parallel by accident.
688 // This lock must be acquired here so the waiter will find
689 // any successful result in the SystemDictionary and not attempt
690 // the define
691 // ParallelCapable Classloaders and the bootstrap classloader,
692 // or all classloaders with UnsyncloadClass do not acquire lock here
693 bool DoObjectLock = true;
694 if (is_parallelCapable(class_loader)) {
695 DoObjectLock = false;
696 }
697
698 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
699 int p_index = placeholders()->hash_to_index(p_hash);
700
701 // Class is not in SystemDictionary so we have to do loading.
702 // Make sure we are synchronized on the class loader before we proceed
703 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
704 check_loader_lock_contention(lockObject, THREAD);
705 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
706
707 // Check again (after locking) if class already exist in SystemDictionary
708 bool class_has_been_loaded = false;
709 bool super_load_in_progress = false;
710 bool havesupername = false;
711 instanceKlassHandle k;
712 PlaceholderEntry* placeholder;
713 Symbol* superclassname = NULL;
714
715 {
716 MutexLocker mu(SystemDictionary_lock, THREAD);
717 Klass* check = find_class(d_index, d_hash, name, loader_data);
718 if (check != NULL) {
719 // Klass is already loaded, so just return it
720 class_has_been_loaded = true;
721 k = instanceKlassHandle(THREAD, check);
722 } else {
723 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (placeholder && placeholder->super_load_in_progress()) {
725 super_load_in_progress = true;
726 if (placeholder->havesupername() == true) {
727 superclassname = placeholder->supername();
728 havesupername = true;
729 }
730 }
731 }
732 }
733
734 // If the class is in the placeholder table, class loading is in progress
735 if (super_load_in_progress && havesupername==true) {
736 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
737 class_loader, protection_domain, lockObject, THREAD);
738 if (HAS_PENDING_EXCEPTION) {
739 return NULL;
740 }
741 if (!k.is_null()) {
742 class_has_been_loaded = true;
743 }
744 }
745
746 bool throw_circularity_error = false;
747 if (!class_has_been_loaded) {
748 bool load_instance_added = false;
749
750 // add placeholder entry to record loading instance class
751 // Five cases:
752 // All cases need to prevent modifying bootclasssearchpath
753 // in parallel with a classload of same classname
754 // Redefineclasses uses existence of the placeholder for the duration
755 // of the class load to prevent concurrent redefinition of not completely
756 // defined classes.
757 // case 1. traditional classloaders that rely on the classloader object lock
758 // - no other need for LOAD_INSTANCE
759 // case 2. traditional classloaders that break the classloader object lock
760 // as a deadlock workaround. Detection of this case requires that
761 // this check is done while holding the classloader object lock,
762 // and that lock is still held when calling classloader's loadClass.
763 // For these classloaders, we ensure that the first requestor
764 // completes the load and other requestors wait for completion.
765 // case 3. UnsyncloadClass - don't use objectLocker
766 // With this flag, we allow parallel classloading of a
767 // class/classloader pair
768 // case4. Bootstrap classloader - don't own objectLocker
769 // This classloader supports parallelism at the classloader level,
770 // but only allows a single load of a class/classloader pair.
771 // No performance benefit and no deadlock issues.
772 // case 5. parallelCapable user level classloaders - without objectLocker
773 // Allow parallel classloading of a class/classloader pair
774
775 {
776 MutexLocker mu(SystemDictionary_lock, THREAD);
777 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
778 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
779 if (oldprobe) {
780 // only need check_seen_thread once, not on each loop
781 // 6341374 java/lang/Instrument with -Xcomp
782 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
783 throw_circularity_error = true;
784 } else {
785 // case 1: traditional: should never see load_in_progress.
786 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
787
788 // case 4: bootstrap classloader: prevent futile classloading,
789 // wait on first requestor
790 if (class_loader.is_null()) {
791 SystemDictionary_lock->wait();
792 } else {
793 // case 2: traditional with broken classloader lock. wait on first
794 // requestor.
795 double_lock_wait(lockObject, THREAD);
796 }
797 // Check if classloading completed while we were waiting
798 Klass* check = find_class(d_index, d_hash, name, loader_data);
799 if (check != NULL) {
800 // Klass is already loaded, so just return it
801 k = instanceKlassHandle(THREAD, check);
802 class_has_been_loaded = true;
803 }
804 // check if other thread failed to load and cleaned up
805 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
806 }
807 }
808 }
809 }
810 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
811 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
812 // LOAD_INSTANCE in parallel
813
814 if (!throw_circularity_error && !class_has_been_loaded) {
815 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
816 load_instance_added = true;
817 // For class loaders that do not acquire the classloader object lock,
818 // if they did not catch another thread holding LOAD_INSTANCE,
819 // need a check analogous to the acquire ObjectLocker/find_class
820 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
821 // one final check if the load has already completed
822 // class loaders holding the ObjectLock shouldn't find the class here
823 Klass* check = find_class(d_index, d_hash, name, loader_data);
824 if (check != NULL) {
825 // Klass is already loaded, so return it after checking/adding protection domain
826 k = instanceKlassHandle(THREAD, check);
827 class_has_been_loaded = true;
828 }
829 }
830 }
831
832 // must throw error outside of owning lock
833 if (throw_circularity_error) {
834 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
835 ResourceMark rm(THREAD);
836 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
837 }
838
839 if (!class_has_been_loaded) {
840
841 // Do actual loading
842 k = load_instance_class(name, class_loader, THREAD);
843
844 // For UnsyncloadClass only
845 // If they got a linkageError, check if a parallel class load succeeded.
846 // If it did, then for bytecode resolution the specification requires
847 // that we return the same result we did for the other thread, i.e. the
848 // successfully loaded InstanceKlass
849 // Should not get here for classloaders that support parallelism
850 // with the new cleaner mechanism, even with AllowParallelDefineClass
851 // Bootstrap goes through here to allow for an extra guarantee check
852 if (UnsyncloadClass || (class_loader.is_null())) {
853 if (k.is_null() && HAS_PENDING_EXCEPTION
854 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
855 MutexLocker mu(SystemDictionary_lock, THREAD);
856 Klass* check = find_class(d_index, d_hash, name, loader_data);
857 if (check != NULL) {
858 // Klass is already loaded, so just use it
859 k = instanceKlassHandle(THREAD, check);
860 CLEAR_PENDING_EXCEPTION;
861 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
862 }
863 }
864 }
865
866 // If everything was OK (no exceptions, no null return value), and
867 // class_loader is NOT the defining loader, do a little more bookkeeping.
868 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
869 k->class_loader() != class_loader()) {
870
871 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
872
873 // Need to check for a PENDING_EXCEPTION again; check_constraints
874 // can throw and doesn't use the CHECK macro.
875 if (!HAS_PENDING_EXCEPTION) {
876 { // Grabbing the Compile_lock prevents systemDictionary updates
877 // during compilations.
878 MutexLocker mu(Compile_lock, THREAD);
879 update_dictionary(d_index, d_hash, p_index, p_hash,
880 k, class_loader, THREAD);
881 }
882
883 if (JvmtiExport::should_post_class_load()) {
884 Thread *thread = THREAD;
885 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
886 JvmtiExport::post_class_load((JavaThread *) thread, k());
887 }
888 }
889 }
890 } // load_instance_class loop
891
892 if (load_instance_added == true) {
893 // clean up placeholder entries for LOAD_INSTANCE success or error
894 // This brackets the SystemDictionary updates for both defining
895 // and initiating loaders
896 MutexLocker mu(SystemDictionary_lock, THREAD);
897 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
898 SystemDictionary_lock->notify_all();
899 }
900 }
901
902 if (HAS_PENDING_EXCEPTION || k.is_null()) {
903 return NULL;
904 }
905
906 post_class_load_event(class_load_start_time, k, loader_data);
907
908 #ifdef ASSERT
909 {
910 ClassLoaderData* loader_data = k->class_loader_data();
911 MutexLocker mu(SystemDictionary_lock, THREAD);
912 Klass* kk = find_class(name, loader_data);
913 assert(kk == k(), "should be present in dictionary");
914 }
915 #endif
916
917 // return if the protection domain in NULL
918 if (protection_domain() == NULL) return k();
919
920 // Check the protection domain has the right access
921 {
922 MutexLocker mu(SystemDictionary_lock, THREAD);
923 // Note that we have an entry, and entries can be deleted only during GC,
924 // so we cannot allow GC to occur while we're holding this entry.
925 // We're using a NoSafepointVerifier to catch any place where we
926 // might potentially do a GC at all.
927 // Dictionary::do_unloading() asserts that classes in SD are only
928 // unloaded at a safepoint. Anonymous classes are not in SD.
929 NoSafepointVerifier nosafepoint;
930 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
931 loader_data,
932 protection_domain)) {
933 return k();
934 }
935 }
936
937 // Verify protection domain. If it fails an exception is thrown
938 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
939
940 return k();
941 }
942
943
944 // This routine does not lock the system dictionary.
945 //
946 // Since readers don't hold a lock, we must make sure that system
947 // dictionary entries are only removed at a safepoint (when only one
948 // thread is running), and are added to in a safe way (all links must
949 // be updated in an MT-safe manner).
950 //
951 // Callers should be aware that an entry could be added just after
952 // _dictionary->bucket(index) is read here, so the caller will not see
953 // the new entry.
954
955 Klass* SystemDictionary::find(Symbol* class_name,
956 Handle class_loader,
957 Handle protection_domain,
958 TRAPS) {
959
960 // The result of this call should be consistent with the result
961 // of the call to resolve_instance_class_or_null().
962 // See evaluation 6790209 and 4474172 for more details.
963 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
964 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
965
966 if (loader_data == NULL) {
967 // If the ClassLoaderData has not been setup,
968 // then the class loader has no entries in the dictionary.
969 return NULL;
970 }
971
972 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
973 int d_index = dictionary()->hash_to_index(d_hash);
974
975 {
976 // Note that we have an entry, and entries can be deleted only during GC,
977 // so we cannot allow GC to occur while we're holding this entry.
978 // We're using a NoSafepointVerifier to catch any place where we
979 // might potentially do a GC at all.
980 // Dictionary::do_unloading() asserts that classes in SD are only
981 // unloaded at a safepoint. Anonymous classes are not in SD.
982 NoSafepointVerifier nosafepoint;
983 return dictionary()->find(d_index, d_hash, class_name, loader_data,
984 protection_domain, THREAD);
985 }
986 }
987
988
989 // Look for a loaded instance or array klass by name. Do not do any loading.
990 // return NULL in case of error.
991 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
992 Handle class_loader,
993 Handle protection_domain,
994 TRAPS) {
995 Klass* k = NULL;
996 assert(class_name != NULL, "class name must be non NULL");
997
998 if (FieldType::is_array(class_name)) {
999 // The name refers to an array. Parse the name.
1000 // dimension and object_key in FieldArrayInfo are assigned as a
1001 // side-effect of this call
1002 FieldArrayInfo fd;
1003 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1004 if (t != T_OBJECT) {
1005 k = Universe::typeArrayKlassObj(t);
1006 } else {
1007 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1008 }
1009 if (k != NULL) {
1010 k = k->array_klass_or_null(fd.dimension());
1011 }
1012 } else {
1013 k = find(class_name, class_loader, protection_domain, THREAD);
1014 }
1015 return k;
1016 }
1017
1018 // Note: this method is much like resolve_from_stream, but
1019 // does not publish the classes via the SystemDictionary.
1020 // Handles unsafe_DefineAnonymousClass and redefineclasses
1021 // RedefinedClasses do not add to the class hierarchy
1022 Klass* SystemDictionary::parse_stream(Symbol* class_name,
1023 Handle class_loader,
1024 Handle protection_domain,
1025 ClassFileStream* st,
1026 const InstanceKlass* host_klass,
1027 GrowableArray<Handle>* cp_patches,
1028 TRAPS) {
1029
1030 Ticks class_load_start_time = Ticks::now();
1031
1032 ClassLoaderData* loader_data;
1033 if (host_klass != NULL) {
1034 // Create a new CLD for anonymous class, that uses the same class loader
1035 // as the host_klass
1036 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1037 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1038 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1039 loader_data->record_dependency(host_klass, CHECK_NULL);
1040 } else {
1041 loader_data = ClassLoaderData::class_loader_data(class_loader());
1042 }
1043
1044 assert(st != NULL, "invariant");
1045 assert(st->need_verify(), "invariant");
1046
1047 // Parse stream and create a klass.
1048 // Note that we do this even though this klass might
1049 // already be present in the SystemDictionary, otherwise we would not
1050 // throw potential ClassFormatErrors.
1051
1052 instanceKlassHandle k = KlassFactory::create_from_stream(st,
1053 class_name,
1054 loader_data,
1055 protection_domain,
1056 host_klass,
1057 cp_patches,
1058 CHECK_NULL);
1059
1060 if (host_klass != NULL && k.not_null()) {
1061 // If it's anonymous, initialize it now, since nobody else will.
1062
1063 {
1064 MutexLocker mu_r(Compile_lock, THREAD);
1065
1066 // Add to class hierarchy, initialize vtables, and do possible
1067 // deoptimizations.
1068 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1069
1070 // But, do not add to system dictionary.
1071
1072 // compiled code dependencies need to be validated anyway
1073 notice_modification();
1074 }
1075
1076 // Rewrite and patch constant pool here.
1077 k->link_class(CHECK_NULL);
1078 if (cp_patches != NULL) {
1079 k->constants()->patch_resolved_references(cp_patches);
1080 }
1081 k->eager_initialize(CHECK_NULL);
1082
1083 // notify jvmti
1084 if (JvmtiExport::should_post_class_load()) {
1085 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1086 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1087 }
1088
1089 post_class_load_event(class_load_start_time, k, loader_data);
1090 }
1091 assert(host_klass != NULL || NULL == cp_patches,
1092 "cp_patches only found with host_klass");
1093
1094 return k();
1095 }
1096
1097 // Add a klass to the system from a stream (called by jni_DefineClass and
1098 // JVM_DefineClass).
1099 // Note: class_name can be NULL. In that case we do not know the name of
1100 // the class until we have parsed the stream.
1101
1102 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1103 Handle class_loader,
1104 Handle protection_domain,
1105 ClassFileStream* st,
1106 TRAPS) {
1107
1108 HandleMark hm(THREAD);
1109
1110 // Classloaders that support parallelism, e.g. bootstrap classloader,
1111 // or all classloaders with UnsyncloadClass do not acquire lock here
1112 bool DoObjectLock = true;
1113 if (is_parallelCapable(class_loader)) {
1114 DoObjectLock = false;
1115 }
1116
1117 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1118
1119 // Make sure we are synchronized on the class loader before we proceed
1120 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1121 check_loader_lock_contention(lockObject, THREAD);
1122 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1123
1124 assert(st != NULL, "invariant");
1125
1126 // Parse the stream and create a klass.
1127 // Note that we do this even though this klass might
1128 // already be present in the SystemDictionary, otherwise we would not
1129 // throw potential ClassFormatErrors.
1130 //
1131
1132 instanceKlassHandle k;
1133
1134 #if INCLUDE_CDS
1135 k = SystemDictionaryShared::lookup_from_stream(class_name,
1136 class_loader,
1137 protection_domain,
1138 st,
1139 CHECK_NULL);
1140 #endif
1141
1142 if (k.is_null()) {
1143 if (st->buffer() == NULL) {
1144 return NULL;
1145 }
1146 k = KlassFactory::create_from_stream(st,
1147 class_name,
1148 loader_data,
1149 protection_domain,
1150 NULL, // host_klass
1151 NULL, // cp_patches
1152 CHECK_NULL);
1153 }
1154
1155 assert(k.not_null(), "no klass created");
1156 Symbol* h_name = k->name();
1157 assert(class_name == NULL || class_name == h_name, "name mismatch");
1158
1159 bool define_succeeded = false;
1160 // Add class just loaded
1161 // If a class loader supports parallel classloading handle parallel define requests
1162 // find_or_define_instance_class may return a different InstanceKlass
1163 if (is_parallelCapable(class_loader)) {
1164 instanceKlassHandle defined_k = find_or_define_instance_class(h_name, class_loader, k, CHECK_NULL);
1165 if (k() == defined_k()) {
1166 // we have won over other concurrent threads (if any) that are
1167 // competing to define the same class.
1168 define_succeeded = true;
1169 }
1170 k = defined_k;
1171 } else {
1172 define_instance_class(k, CHECK_NULL);
1173 define_succeeded = true;
1174 }
1175
1176 // Make sure we have an entry in the SystemDictionary on success
1177 debug_only( {
1178 MutexLocker mu(SystemDictionary_lock, THREAD);
1179
1180 Klass* check = find_class(h_name, k->class_loader_data());
1181 assert(check == k(), "should be present in the dictionary");
1182 } );
1183
1184 return k();
1185 }
1186
1187 #if INCLUDE_CDS
1188 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1189 int number_of_entries) {
1190 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1191 "bad shared dictionary size.");
1192 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1193 }
1194
1195
1196 // If there is a shared dictionary, then find the entry for the
1197 // given shared system class, if any.
1198
1199 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1200 if (shared_dictionary() != NULL) {
1201 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1202 int d_index = shared_dictionary()->hash_to_index(d_hash);
1203
1204 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1205 } else {
1206 return NULL;
1207 }
1208 }
1209
1210
1211 // Load a class from the shared spaces (found through the shared system
1212 // dictionary). Force the superclass and all interfaces to be loaded.
1213 // Update the class definition to include sibling classes and no
1214 // subclasses (yet). [Classes in the shared space are not part of the
1215 // object hierarchy until loaded.]
1216
1217 instanceKlassHandle SystemDictionary::load_shared_class(
1218 Symbol* class_name, Handle class_loader, TRAPS) {
1219 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1220 // Make sure we only return the boot class for the NULL classloader.
1221 if (ik.not_null() &&
1222 ik->is_shared_boot_class() && class_loader.is_null()) {
1223 Handle protection_domain;
1224 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1225 }
1226 return instanceKlassHandle();
1227 }
1228
1229 // Check if a shared class can be loaded by the specific classloader:
1230 //
1231 // NULL classloader:
1232 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1233 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1234 // be defined in an unnamed module.
1235 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1236 instanceKlassHandle ik,
1237 Handle class_loader, TRAPS) {
1238 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1239 "Cannot use sharing if java.base is patched");
1240 ResourceMark rm;
1241 int path_index = ik->shared_classpath_index();
1242 SharedClassPathEntry* ent =
1243 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1244 if (!Universe::is_module_initialized()) {
1245 assert(ent != NULL && ent->is_jrt(),
1246 "Loading non-bootstrap classes before the module system is initialized");
1247 assert(class_loader.is_null(), "sanity");
1248 return true;
1249 }
1250 // Get the pkg_entry from the classloader
1251 TempNewSymbol pkg_name = NULL;
1252 PackageEntry* pkg_entry = NULL;
1253 ModuleEntry* mod_entry = NULL;
1254 const char* pkg_string = NULL;
1255 ClassLoaderData* loader_data = class_loader_data(class_loader);
1256 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1257 if (pkg_name != NULL) {
1258 pkg_string = pkg_name->as_C_string();
1259 if (loader_data != NULL) {
1260 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1261 }
1262 if (pkg_entry != NULL) {
1263 mod_entry = pkg_entry->module();
1264 }
1265 }
1266
1267 // If the archived class is from a module that has been patched at runtime,
1268 // the class cannot be loaded from the archive.
1269 if (mod_entry != NULL && mod_entry->is_patched()) {
1270 return false;
1271 }
1272
1273 if (class_loader.is_null()) {
1274 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1275 // The NULL classloader can load archived class originated from the
1276 // "modules" jimage and the -Xbootclasspath/a. For class from the
1277 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1278 // by the NULL classloader.
1279 if (mod_entry != NULL) {
1280 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1281 // ModuleEntry's location agrees with the archived class' origination.
1282 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1283 return true; // Module class from the "module" jimage
1284 }
1285 }
1286
1287 // If the archived class is not from the "module" jimage, the class can be
1288 // loaded by the NULL classloader if
1289 //
1290 // 1. the class is from the unamed package
1291 // 2. or, the class is not from a module defined in the NULL classloader
1292 // 3. or, the class is from an unamed module
1293 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1294 // the class is from the -Xbootclasspath/a
1295 if (pkg_string == NULL ||
1296 pkg_entry == NULL ||
1297 pkg_entry->in_unnamed_module()) {
1298 assert(mod_entry == NULL ||
1299 mod_entry == loader_data->modules()->unnamed_module(),
1300 "the unnamed module is not defined in the classloader");
1301 return true;
1302 }
1303 }
1304 return false;
1305 } else {
1306 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1307 ik, class_loader, pkg_string, pkg_name,
1308 pkg_entry, mod_entry, CHECK_(false));
1309 return res;
1310 }
1311 }
1312
1313 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1314 Handle class_loader,
1315 Handle protection_domain, TRAPS) {
1316 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1317
1318 if (ik.not_null()) {
1319 Symbol* class_name = ik->name();
1320
1321 bool visible = is_shared_class_visible(
1322 class_name, ik, class_loader, CHECK_(nh));
1323 if (!visible) {
1324 return nh;
1325 }
1326
1327 // Resolve the superclass and interfaces. They must be the same
1328 // as in dump time, because the layout of <ik> depends on
1329 // the specific layout of ik->super() and ik->local_interfaces().
1330 //
1331 // If unexpected superclass or interfaces are found, we cannot
1332 // load <ik> from the shared archive.
1333
1334 if (ik->super() != NULL) {
1335 Symbol* cn = ik->super()->name();
1336 Klass *s = resolve_super_or_fail(class_name, cn,
1337 class_loader, protection_domain, true, CHECK_(nh));
1338 if (s != ik->super()) {
1339 // The dynamically resolved super class is not the same as the one we used during dump time,
1340 // so we cannot use ik.
1341 return nh;
1342 } else {
1343 assert(s->is_shared(), "must be");
1344 }
1345 }
1346
1347 Array<Klass*>* interfaces = ik->local_interfaces();
1348 int num_interfaces = interfaces->length();
1349 for (int index = 0; index < num_interfaces; index++) {
1350 Klass* k = interfaces->at(index);
1351
1352 // Note: can not use InstanceKlass::cast here because
1353 // interfaces' InstanceKlass's C++ vtbls haven't been
1354 // reinitialized yet (they will be once the interface classes
1355 // are loaded)
1356 Symbol* name = k->name();
1357 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1358 if (k != i) {
1359 // The dynamically resolved interface class is not the same as the one we used during dump time,
1360 // so we cannot use ik.
1361 return nh;
1362 } else {
1363 assert(i->is_shared(), "must be");
1364 }
1365 }
1366
1367 instanceKlassHandle new_ik = KlassFactory::check_shared_class_file_load_hook(
1368 ik, class_name, class_loader, protection_domain, CHECK_(nh));
1369 if (new_ik.not_null()) {
1370 // The class is changed by CFLH. Return the new class. The shared class is
1371 // not used.
1372 return new_ik;
1373 }
1374
1375 // Adjust methods to recover missing data. They need addresses for
1376 // interpreter entry points and their default native method address
1377 // must be reset.
1378
1379 // Updating methods must be done under a lock so multiple
1380 // threads don't update these in parallel
1381 //
1382 // Shared classes are all currently loaded by either the bootstrap or
1383 // internal parallel class loaders, so this will never cause a deadlock
1384 // on a custom class loader lock.
1385
1386 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1387 {
1388 HandleMark hm(THREAD);
1389 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1390 check_loader_lock_contention(lockObject, THREAD);
1391 ObjectLocker ol(lockObject, THREAD, true);
1392 // prohibited package check assumes all classes loaded from archive call
1393 // restore_unshareable_info which calls ik->set_package()
1394 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1395 }
1396
1397 if (log_is_enabled(Info, class, load)) {
1398 ik()->print_loading_log(LogLevel::Info, loader_data, NULL, NULL);
1399 }
1400 // No 'else' here as logging levels are not mutually exclusive
1401
1402 if (log_is_enabled(Debug, class, load)) {
1403 ik()->print_loading_log(LogLevel::Debug, loader_data, NULL, NULL);
1404 }
1405
1406 // For boot loader, ensure that GetSystemPackage knows that a class in this
1407 // package was loaded.
1408 if (class_loader.is_null()) {
1409 int path_index = ik->shared_classpath_index();
1410 ResourceMark rm;
1411 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1412 }
1413
1414 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1415 // Only dump the classes that can be stored into CDS archive
1416 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1417 ResourceMark rm(THREAD);
1418 classlist_file->print_cr("%s", ik->name()->as_C_string());
1419 classlist_file->flush();
1420 }
1421 }
1422
1423 // notify a class loaded from shared object
1424 ClassLoadingService::notify_class_loaded(ik(), true /* shared class */);
1425 }
1426
1427 ik->set_has_passed_fingerprint_check(false);
1428 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1429 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik());
1430 uint64_t cds_fp = ik->get_stored_fingerprint();
1431 if (aot_fp != 0 && aot_fp == cds_fp) {
1432 // This class matches with a class saved in an AOT library
1433 ik->set_has_passed_fingerprint_check(true);
1434 } else {
1435 ResourceMark rm;
1436 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1437 }
1438 }
1439 return ik;
1440 }
1441 #endif // INCLUDE_CDS
1442
1443 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1444 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1445
1446 if (class_loader.is_null()) {
1447 ResourceMark rm;
1448 PackageEntry* pkg_entry = NULL;
1449 bool search_only_bootloader_append = false;
1450 ClassLoaderData *loader_data = class_loader_data(class_loader);
1451
1452 // Find the package in the boot loader's package entry table.
1453 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1454 if (pkg_name != NULL) {
1455 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1456 }
1457
1458 // Prior to attempting to load the class, enforce the boot loader's
1459 // visibility boundaries.
1460 if (!Universe::is_module_initialized()) {
1461 // During bootstrapping, prior to module initialization, any
1462 // class attempting to be loaded must be checked against the
1463 // java.base packages in the boot loader's PackageEntryTable.
1464 // No class outside of java.base is allowed to be loaded during
1465 // this bootstrapping window.
1466 if (!DumpSharedSpaces) {
1467 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1468 // Class is either in the unnamed package or in
1469 // a named package within the unnamed module. Either
1470 // case is outside of java.base, do not attempt to
1471 // load the class post java.base definition. If
1472 // java.base has not been defined, let the class load
1473 // and its package will be checked later by
1474 // ModuleEntryTable::verify_javabase_packages.
1475 if (ModuleEntryTable::javabase_defined()) {
1476 return nh;
1477 }
1478 } else {
1479 // Check that the class' package is defined within java.base.
1480 ModuleEntry* mod_entry = pkg_entry->module();
1481 Symbol* mod_entry_name = mod_entry->name();
1482 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1483 return nh;
1484 }
1485 }
1486 }
1487 } else {
1488 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1489 // After the module system has been initialized, check if the class'
1490 // package is in a module defined to the boot loader.
1491 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1492 // Class is either in the unnamed package, in a named package
1493 // within a module not defined to the boot loader or in a
1494 // a named package within the unnamed module. In all cases,
1495 // limit visibility to search for the class only in the boot
1496 // loader's append path.
1497 search_only_bootloader_append = true;
1498 }
1499 }
1500
1501 // Prior to bootstrapping's module initialization, never load a class outside
1502 // of the boot loader's module path
1503 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1504 !search_only_bootloader_append,
1505 "Attempt to load a class outside of boot loader's module path");
1506
1507 // Search the shared system dictionary for classes preloaded into the
1508 // shared spaces.
1509 instanceKlassHandle k;
1510 {
1511 #if INCLUDE_CDS
1512 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1513 k = load_shared_class(class_name, class_loader, THREAD);
1514 #endif
1515 }
1516
1517 if (k.is_null()) {
1518 // Use VM class loader
1519 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1520 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_(nh));
1521 }
1522
1523 // find_or_define_instance_class may return a different InstanceKlass
1524 if (!k.is_null()) {
1525 instanceKlassHandle defined_k =
1526 find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1527 k = defined_k;
1528 }
1529 return k;
1530 } else {
1531 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1532 ResourceMark rm(THREAD);
1533
1534 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1535 JavaThread* jt = (JavaThread*) THREAD;
1536
1537 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1538 ClassLoader::perf_app_classload_selftime(),
1539 ClassLoader::perf_app_classload_count(),
1540 jt->get_thread_stat()->perf_recursion_counts_addr(),
1541 jt->get_thread_stat()->perf_timers_addr(),
1542 PerfClassTraceTime::CLASS_LOAD);
1543
1544 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1545 // Translate to external class name format, i.e., convert '/' chars to '.'
1546 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1547
1548 JavaValue result(T_OBJECT);
1549
1550 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1551
1552 // Call public unsynchronized loadClass(String) directly for all class loaders
1553 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1554 // acquire a class-name based lock rather than the class loader object lock.
1555 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1556 // so the call to loadClassInternal() was not required.
1557 //
1558 // UnsyncloadClass flag means both call loadClass(String) and do
1559 // not acquire the class loader lock even for class loaders that are
1560 // not parallelCapable. This was a risky transitional
1561 // flag for diagnostic purposes only. It is risky to call
1562 // custom class loaders without synchronization.
1563 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1564 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1565 // Do NOT assume this will be supported in future releases.
1566 //
1567 // Added MustCallLoadClassInternal in case we discover in the field
1568 // a customer that counts on this call
1569 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1570 JavaCalls::call_special(&result,
1571 class_loader,
1572 spec_klass,
1573 vmSymbols::loadClassInternal_name(),
1574 vmSymbols::string_class_signature(),
1575 string,
1576 CHECK_(nh));
1577 } else {
1578 JavaCalls::call_virtual(&result,
1579 class_loader,
1580 spec_klass,
1581 vmSymbols::loadClass_name(),
1582 vmSymbols::string_class_signature(),
1583 string,
1584 CHECK_(nh));
1585 }
1586
1587 assert(result.get_type() == T_OBJECT, "just checking");
1588 oop obj = (oop) result.get_jobject();
1589
1590 // Primitive classes return null since forName() can not be
1591 // used to obtain any of the Class objects representing primitives or void
1592 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1593 instanceKlassHandle k =
1594 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1595 // For user defined Java class loaders, check that the name returned is
1596 // the same as that requested. This check is done for the bootstrap
1597 // loader when parsing the class file.
1598 if (class_name == k->name()) {
1599 return k;
1600 }
1601 }
1602 // Class is not found or has the wrong name, return NULL
1603 return nh;
1604 }
1605 }
1606
1607 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1608
1609 HandleMark hm(THREAD);
1610 ClassLoaderData* loader_data = k->class_loader_data();
1611 Handle class_loader_h(THREAD, loader_data->class_loader());
1612
1613 // for bootstrap and other parallel classloaders don't acquire lock,
1614 // use placeholder token
1615 // If a parallelCapable class loader calls define_instance_class instead of
1616 // find_or_define_instance_class to get here, we have a timing
1617 // hole with systemDictionary updates and check_constraints
1618 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1619 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1620 compute_loader_lock_object(class_loader_h, THREAD)),
1621 "define called without lock");
1622 }
1623
1624 // Check class-loading constraints. Throw exception if violation is detected.
1625 // Grabs and releases SystemDictionary_lock
1626 // The check_constraints/find_class call and update_dictionary sequence
1627 // must be "atomic" for a specific class/classloader pair so we never
1628 // define two different instanceKlasses for that class/classloader pair.
1629 // Existing classloaders will call define_instance_class with the
1630 // classloader lock held
1631 // Parallel classloaders will call find_or_define_instance_class
1632 // which will require a token to perform the define class
1633 Symbol* name_h = k->name();
1634 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1635 int d_index = dictionary()->hash_to_index(d_hash);
1636 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1637
1638 // Register class just loaded with class loader (placed in Vector)
1639 // Note we do this before updating the dictionary, as this can
1640 // fail with an OutOfMemoryError (if it does, we will *not* put this
1641 // class in the dictionary and will not update the class hierarchy).
1642 // JVMTI FollowReferences needs to find the classes this way.
1643 if (k->class_loader() != NULL) {
1644 methodHandle m(THREAD, Universe::loader_addClass_method());
1645 JavaValue result(T_VOID);
1646 JavaCallArguments args(class_loader_h);
1647 args.push_oop(Handle(THREAD, k->java_mirror()));
1648 JavaCalls::call(&result, m, &args, CHECK);
1649 }
1650
1651 // Add the new class. We need recompile lock during update of CHA.
1652 {
1653 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1654 int p_index = placeholders()->hash_to_index(p_hash);
1655
1656 MutexLocker mu_r(Compile_lock, THREAD);
1657
1658 // Add to class hierarchy, initialize vtables, and do possible
1659 // deoptimizations.
1660 add_to_hierarchy(k, CHECK); // No exception, but can block
1661
1662 // Add to systemDictionary - so other classes can see it.
1663 // Grabs and releases SystemDictionary_lock
1664 update_dictionary(d_index, d_hash, p_index, p_hash,
1665 k, class_loader_h, THREAD);
1666 }
1667 k->eager_initialize(THREAD);
1668
1669 // notify jvmti
1670 if (JvmtiExport::should_post_class_load()) {
1671 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1672 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1673
1674 }
1675 class_define_event(k, loader_data);
1676 }
1677
1678 // Support parallel classloading
1679 // All parallel class loaders, including bootstrap classloader
1680 // lock a placeholder entry for this class/class_loader pair
1681 // to allow parallel defines of different classes for this class loader
1682 // With AllowParallelDefine flag==true, in case they do not synchronize around
1683 // FindLoadedClass/DefineClass, calls, we check for parallel
1684 // loading for them, wait if a defineClass is in progress
1685 // and return the initial requestor's results
1686 // This flag does not apply to the bootstrap classloader.
1687 // With AllowParallelDefine flag==false, call through to define_instance_class
1688 // which will throw LinkageError: duplicate class definition.
1689 // False is the requested default.
1690 // For better performance, the class loaders should synchronize
1691 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1692 // potentially waste time reading and parsing the bytestream.
1693 // Note: VM callers should ensure consistency of k/class_name,class_loader
1694 // Be careful when modifying this code: once you have run
1695 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1696 // you need to find_and_remove it before returning.
1697 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1698 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1699
1700 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1701 Symbol* name_h = k->name(); // passed in class_name may be null
1702 ClassLoaderData* loader_data = class_loader_data(class_loader);
1703
1704 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1705 int d_index = dictionary()->hash_to_index(d_hash);
1706
1707 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1708 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1709 int p_index = placeholders()->hash_to_index(p_hash);
1710 PlaceholderEntry* probe;
1711
1712 {
1713 MutexLocker mu(SystemDictionary_lock, THREAD);
1714 // First check if class already defined
1715 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1716 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1717 if (check != NULL) {
1718 return(instanceKlassHandle(THREAD, check));
1719 }
1720 }
1721
1722 // Acquire define token for this class/classloader
1723 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1724 // Wait if another thread defining in parallel
1725 // All threads wait - even those that will throw duplicate class: otherwise
1726 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1727 // if other thread has not finished updating dictionary
1728 while (probe->definer() != NULL) {
1729 SystemDictionary_lock->wait();
1730 }
1731 // Only special cases allow parallel defines and can use other thread's results
1732 // Other cases fall through, and may run into duplicate defines
1733 // caught by finding an entry in the SystemDictionary
1734 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1735 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1736 SystemDictionary_lock->notify_all();
1737 #ifdef ASSERT
1738 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1739 assert(check != NULL, "definer missed recording success");
1740 #endif
1741 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1742 } else {
1743 // This thread will define the class (even if earlier thread tried and had an error)
1744 probe->set_definer(THREAD);
1745 }
1746 }
1747
1748 define_instance_class(k, THREAD);
1749
1750 Handle linkage_exception = Handle(); // null handle
1751
1752 // definer must notify any waiting threads
1753 {
1754 MutexLocker mu(SystemDictionary_lock, THREAD);
1755 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1756 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1757 if (probe != NULL) {
1758 if (HAS_PENDING_EXCEPTION) {
1759 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1760 CLEAR_PENDING_EXCEPTION;
1761 } else {
1762 probe->set_instance_klass(k());
1763 }
1764 probe->set_definer(NULL);
1765 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1766 SystemDictionary_lock->notify_all();
1767 }
1768 }
1769
1770 // Can't throw exception while holding lock due to rank ordering
1771 if (linkage_exception() != NULL) {
1772 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1773 }
1774
1775 return k;
1776 }
1777 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1778 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1779 if (class_loader.is_null()) {
1780 return Handle(THREAD, _system_loader_lock_obj);
1781 } else {
1782 return class_loader;
1783 }
1784 }
1785
1786 // This method is added to check how often we have to wait to grab loader
1787 // lock. The results are being recorded in the performance counters defined in
1788 // ClassLoader::_sync_systemLoaderLockContentionRate and
1789 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1790 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1791 if (!UsePerfData) {
1792 return;
1793 }
1794
1795 assert(!loader_lock.is_null(), "NULL lock object");
1796
1797 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1798 == ObjectSynchronizer::owner_other) {
1799 // contention will likely happen, so increment the corresponding
1800 // contention counter.
1801 if (loader_lock() == _system_loader_lock_obj) {
1802 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1803 } else {
1804 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1805 }
1806 }
1807 }
1808
1809 // ----------------------------------------------------------------------------
1810 // Lookup
1811
1812 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1813 Symbol* class_name,
1814 ClassLoaderData* loader_data) {
1815 assert_locked_or_safepoint(SystemDictionary_lock);
1816 assert (index == dictionary()->index_for(class_name, loader_data),
1817 "incorrect index?");
1818
1819 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1820 return k;
1821 }
1822
1823
1824 // Basic find on classes in the midst of being loaded
1825 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1826 ClassLoaderData* loader_data) {
1827 assert_locked_or_safepoint(SystemDictionary_lock);
1828 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1829 int p_index = placeholders()->hash_to_index(p_hash);
1830 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1831 }
1832
1833
1834 // Used for assertions and verification only
1835 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1836 #ifndef ASSERT
1837 guarantee(VerifyBeforeGC ||
1838 VerifyDuringGC ||
1839 VerifyBeforeExit ||
1840 VerifyDuringStartup ||
1841 VerifyAfterGC, "too expensive");
1842 #endif
1843 assert_locked_or_safepoint(SystemDictionary_lock);
1844
1845 // First look in the loaded class array
1846 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1847 int d_index = dictionary()->hash_to_index(d_hash);
1848 return find_class(d_index, d_hash, class_name, loader_data);
1849 }
1850
1851
1852 // Get the next class in the dictionary.
1853 Klass* SystemDictionary::try_get_next_class() {
1854 return dictionary()->try_get_next_class();
1855 }
1856
1857
1858 // ----------------------------------------------------------------------------
1859 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1860 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1861 // before a new class is used.
1862
1863 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1864 assert(k.not_null(), "just checking");
1865 assert_locked_or_safepoint(Compile_lock);
1866
1867 // Link into hierachy. Make sure the vtables are initialized before linking into
1868 k->append_to_sibling_list(); // add to superklass/sibling list
1869 k->process_interfaces(THREAD); // handle all "implements" declarations
1870 k->set_init_state(InstanceKlass::loaded);
1871 // Now flush all code that depended on old class hierarchy.
1872 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1873 // Also, first reinitialize vtable because it may have gotten out of synch
1874 // while the new class wasn't connected to the class hierarchy.
1875 CodeCache::flush_dependents_on(k);
1876 }
1877
1878 // ----------------------------------------------------------------------------
1879 // GC support
1880
1881 // Following roots during mark-sweep is separated in two phases.
1882 //
1883 // The first phase follows preloaded classes and all other system
1884 // classes, since these will never get unloaded anyway.
1885 //
1886 // The second phase removes (unloads) unreachable classes from the
1887 // system dictionary and follows the remaining classes' contents.
1888
1889 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1890 roots_oops_do(blk, NULL);
1891 }
1892
1893 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1894 // Follow all system classes and temporary placeholders in dictionary
1895 dictionary()->always_strong_classes_do(closure);
1896
1897 // Placeholders. These represent classes we're actively loading.
1898 placeholders()->classes_do(closure);
1899 }
1900
1901 // Calculate a "good" systemdictionary size based
1902 // on predicted or current loaded classes count
1903 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1904 int newsize = _old_default_sdsize;
1905 if ((classcount > 0) && !DumpSharedSpaces) {
1906 int desiredsize = classcount/_average_depth_goal;
1907 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1908 newsize = _primelist[++_sdgeneration]) {
1909 if (desiredsize <= newsize) {
1910 break;
1911 }
1912 }
1913 }
1914 return newsize;
1915 }
1916
1917 #ifdef ASSERT
1918 class VerifySDReachableAndLiveClosure : public OopClosure {
1919 private:
1920 BoolObjectClosure* _is_alive;
1921
1922 template <class T> void do_oop_work(T* p) {
1923 oop obj = oopDesc::load_decode_heap_oop(p);
1924 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1925 }
1926
1927 public:
1928 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1929
1930 virtual void do_oop(oop* p) { do_oop_work(p); }
1931 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1932 };
1933 #endif
1934
1935 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1936 // Note: anonymous classes are not in the SD.
1937 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1938 bool clean_previous_versions) {
1939 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1940 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1941 clean_previous_versions);
1942 if (unloading_occurred) {
1943 dictionary()->do_unloading();
1944 constraints()->purge_loader_constraints();
1945 resolution_errors()->purge_resolution_errors();
1946 }
1947 // Oops referenced by the system dictionary may get unreachable independently
1948 // of the class loader (eg. cached protection domain oops). So we need to
1949 // explicitly unlink them here instead of in Dictionary::do_unloading.
1950 dictionary()->unlink(is_alive);
1951 #ifdef ASSERT
1952 VerifySDReachableAndLiveClosure cl(is_alive);
1953 dictionary()->oops_do(&cl);
1954 #endif
1955 return unloading_occurred;
1956 }
1957
1958 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1959 strong->do_oop(&_java_system_loader);
1960 strong->do_oop(&_system_loader_lock_obj);
1961 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1962
1963 // Adjust dictionary
1964 dictionary()->roots_oops_do(strong, weak);
1965
1966 // Visit extra methods
1967 invoke_method_table()->oops_do(strong);
1968 }
1969
1970 void SystemDictionary::oops_do(OopClosure* f) {
1971 f->do_oop(&_java_system_loader);
1972 f->do_oop(&_system_loader_lock_obj);
1973 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1974
1975 // Adjust dictionary
1976 dictionary()->oops_do(f);
1977
1978 // Visit extra methods
1979 invoke_method_table()->oops_do(f);
1980 }
1981
1982 // Extended Class redefinition support.
1983 // If one of these classes is replaced, we need to replace it in these places.
1984 // KlassClosure::do_klass should take the address of a class but we can
1985 // change that later.
1986 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1987 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1988 f->do_klass(_well_known_klasses[k]);
1989 }
1990
1991 {
1992 for (int i = 0; i < T_VOID+1; i++) {
1993 if (_box_klasses[i] != NULL) {
1994 assert(i >= T_BOOLEAN, "checking");
1995 f->do_klass(_box_klasses[i]);
1996 }
1997 }
1998 }
1999
2000 FilteredFieldsMap::classes_do(f);
2001 }
2002
2003 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
2004 f->do_klass(_abstract_ownable_synchronizer_klass);
2005 }
2006
2007 // Just the classes from defining class loaders
2008 // Don't iterate over placeholders
2009 void SystemDictionary::classes_do(void f(Klass*)) {
2010 dictionary()->classes_do(f);
2011 }
2012
2013 // Added for initialize_itable_for_klass
2014 // Just the classes from defining class loaders
2015 // Don't iterate over placeholders
2016 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
2017 dictionary()->classes_do(f, CHECK);
2018 }
2019
2020 // All classes, and their class loaders
2021 // Don't iterate over placeholders
2022 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
2023 dictionary()->classes_do(f);
2024 }
2025
2026 void SystemDictionary::placeholders_do(void f(Symbol*)) {
2027 placeholders()->entries_do(f);
2028 }
2029
2030 void SystemDictionary::methods_do(void f(Method*)) {
2031 dictionary()->methods_do(f);
2032 invoke_method_table()->methods_do(f);
2033 }
2034
2035 void SystemDictionary::remove_classes_in_error_state() {
2036 dictionary()->remove_classes_in_error_state();
2037 }
2038
2039 // ----------------------------------------------------------------------------
2040 // Lazily load klasses
2041
2042 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2043 // if multiple threads calling this function, only one thread will load
2044 // the class. The other threads will find the loaded version once the
2045 // class is loaded.
2046 Klass* aos = _abstract_ownable_synchronizer_klass;
2047 if (aos == NULL) {
2048 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2049 // Force a fence to prevent any read before the write completes
2050 OrderAccess::fence();
2051 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2052 }
2053 }
2054
2055 // ----------------------------------------------------------------------------
2056 // Initialization
2057
2058 void SystemDictionary::initialize(TRAPS) {
2059 // Allocate arrays
2060 assert(dictionary() == NULL,
2061 "SystemDictionary should only be initialized once");
2062 _sdgeneration = 0;
2063 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2064 _placeholders = new PlaceholderTable(_nof_buckets);
2065 _number_of_modifications = 0;
2066 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2067 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2068 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2069
2070 // Allocate private object used as system class loader lock
2071 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2072 // Initialize basic classes
2073 initialize_preloaded_classes(CHECK);
2074 }
2075
2076 // Compact table of directions on the initialization of klasses:
2077 static const short wk_init_info[] = {
2078 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2079 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2080 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2081 | (int)SystemDictionary::option ),
2082 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2083 #undef WK_KLASS_INIT_INFO
2084 0
2085 };
2086
2087 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2088 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2089 int info = wk_init_info[id - FIRST_WKID];
2090 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2091 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2092 InstanceKlass** klassp = &_well_known_klasses[id];
2093
2094 bool must_load;
2095 #if INCLUDE_JVMCI
2096 if (EnableJVMCI) {
2097 // If JVMCI is enabled we require its classes to be found.
2098 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2099 } else
2100 #endif
2101 {
2102 must_load = (init_opt < SystemDictionary::Opt);
2103 }
2104
2105 if ((*klassp) == NULL) {
2106 Klass* k;
2107 if (must_load) {
2108 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2109 } else {
2110 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2111 }
2112 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2113 }
2114 return ((*klassp) != NULL);
2115 }
2116
2117 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2118 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2119 for (int id = (int)start_id; id < (int)limit_id; id++) {
2120 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2121 int info = wk_init_info[id - FIRST_WKID];
2122 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2123 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2124
2125 initialize_wk_klass((WKID)id, opt, CHECK);
2126 }
2127
2128 // move the starting value forward to the limit:
2129 start_id = limit_id;
2130 }
2131
2132 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2133 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2134
2135 // Create the ModuleEntry for java.base. This call needs to be done here,
2136 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2137 ClassLoader::classLoader_init2(CHECK);
2138
2139 // Preload commonly used klasses
2140 WKID scan = FIRST_WKID;
2141 // first do Object, then String, Class
2142 if (UseSharedSpaces) {
2143 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2144 // Initialize the constant pool for the Object_class
2145 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
2146 ik->constants()->restore_unshareable_info(CHECK);
2147 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2148 } else {
2149 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2150 }
2151
2152 // Calculate offsets for String and Class classes since they are loaded and
2153 // can be used after this point.
2154 java_lang_String::compute_offsets();
2155 java_lang_Class::compute_offsets();
2156
2157 // Fixup mirrors for classes loaded before java.lang.Class.
2158 // These calls iterate over the objects currently in the perm gen
2159 // so calling them at this point is matters (not before when there
2160 // are fewer objects and not later after there are more objects
2161 // in the perm gen.
2162 Universe::initialize_basic_type_mirrors(CHECK);
2163 Universe::fixup_mirrors(CHECK);
2164
2165 // do a bunch more:
2166 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2167
2168 // Preload ref klasses and set reference types
2169 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2170 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2171
2172 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2173 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2174 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2175 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2176 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2177
2178 // JSR 292 classes
2179 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2180 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2181 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2182 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2183 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2184
2185 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2186 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2187 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2188 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2189 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2190 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2191 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2192 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2193 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2194 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2195
2196 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2197 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2198 _has_loadClassInternal = (method != NULL);
2199 }
2200 { // Compute whether we should use checkPackageAccess or NOT
2201 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2202 _has_checkPackageAccess = (method != NULL);
2203 }
2204 }
2205
2206 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2207 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2208 BasicType SystemDictionary::box_klass_type(Klass* k) {
2209 assert(k != NULL, "");
2210 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2211 if (_box_klasses[i] == k)
2212 return (BasicType)i;
2213 }
2214 return T_OBJECT;
2215 }
2216
2217 // Constraints on class loaders. The details of the algorithm can be
2218 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2219 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2220 // that the system dictionary needs to maintain a set of contraints that
2221 // must be satisfied by all classes in the dictionary.
2222 // if defining is true, then LinkageError if already in systemDictionary
2223 // if initiating loader, then ok if InstanceKlass matches existing entry
2224
2225 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2226 instanceKlassHandle k,
2227 Handle class_loader, bool defining,
2228 TRAPS) {
2229 const char *linkage_error1 = NULL;
2230 const char *linkage_error2 = NULL;
2231 {
2232 Symbol* name = k->name();
2233 ClassLoaderData *loader_data = class_loader_data(class_loader);
2234
2235 MutexLocker mu(SystemDictionary_lock, THREAD);
2236
2237 Klass* check = find_class(d_index, d_hash, name, loader_data);
2238 if (check != (Klass*)NULL) {
2239 // if different InstanceKlass - duplicate class definition,
2240 // else - ok, class loaded by a different thread in parallel,
2241 // we should only have found it if it was done loading and ok to use
2242 // system dictionary only holds instance classes, placeholders
2243 // also holds array classes
2244
2245 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2246 if ((defining == true) || (k() != check)) {
2247 linkage_error1 = "loader (instance of ";
2248 linkage_error2 = "): attempted duplicate class definition for name: \"";
2249 } else {
2250 return;
2251 }
2252 }
2253
2254 #ifdef ASSERT
2255 Symbol* ph_check = find_placeholder(name, loader_data);
2256 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2257 #endif
2258
2259 if (linkage_error1 == NULL) {
2260 if (constraints()->check_or_update(k, class_loader, name) == false) {
2261 linkage_error1 = "loader constraint violation: loader (instance of ";
2262 linkage_error2 = ") previously initiated loading for a different type with name \"";
2263 }
2264 }
2265 }
2266
2267 // Throw error now if needed (cannot throw while holding
2268 // SystemDictionary_lock because of rank ordering)
2269
2270 if (linkage_error1) {
2271 ResourceMark rm(THREAD);
2272 const char* class_loader_name = loader_name(class_loader());
2273 char* type_name = k->name()->as_C_string();
2274 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2275 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2276 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2277 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2278 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2279 }
2280 }
2281
2282
2283 // Update system dictionary - done after check_constraint and add_to_hierachy
2284 // have been called.
2285 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2286 int p_index, unsigned int p_hash,
2287 instanceKlassHandle k,
2288 Handle class_loader,
2289 TRAPS) {
2290 // Compile_lock prevents systemDictionary updates during compilations
2291 assert_locked_or_safepoint(Compile_lock);
2292 Symbol* name = k->name();
2293 ClassLoaderData *loader_data = class_loader_data(class_loader);
2294
2295 {
2296 MutexLocker mu1(SystemDictionary_lock, THREAD);
2297
2298 // See whether biased locking is enabled and if so set it for this
2299 // klass.
2300 // Note that this must be done past the last potential blocking
2301 // point / safepoint. We enable biased locking lazily using a
2302 // VM_Operation to iterate the SystemDictionary and installing the
2303 // biasable mark word into each InstanceKlass's prototype header.
2304 // To avoid race conditions where we accidentally miss enabling the
2305 // optimization for one class in the process of being added to the
2306 // dictionary, we must not safepoint after the test of
2307 // BiasedLocking::enabled().
2308 if (UseBiasedLocking && BiasedLocking::enabled()) {
2309 // Set biased locking bit for all loaded classes; it will be
2310 // cleared if revocation occurs too often for this type
2311 // NOTE that we must only do this when the class is initally
2312 // defined, not each time it is referenced from a new class loader
2313 if (k->class_loader() == class_loader()) {
2314 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2315 }
2316 }
2317
2318 // Make a new system dictionary entry.
2319 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2320 if (sd_check == NULL) {
2321 dictionary()->add_klass(name, loader_data, k);
2322 notice_modification();
2323 }
2324 #ifdef ASSERT
2325 sd_check = find_class(d_index, d_hash, name, loader_data);
2326 assert (sd_check != NULL, "should have entry in system dictionary");
2327 // Note: there may be a placeholder entry: for circularity testing
2328 // or for parallel defines
2329 #endif
2330 SystemDictionary_lock->notify_all();
2331 }
2332 }
2333
2334
2335 // Try to find a class name using the loader constraints. The
2336 // loader constraints might know about a class that isn't fully loaded
2337 // yet and these will be ignored.
2338 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2339 Symbol* class_name, Handle class_loader, TRAPS) {
2340
2341 // First see if it has been loaded directly.
2342 // Force the protection domain to be null. (This removes protection checks.)
2343 Handle no_protection_domain;
2344 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2345 no_protection_domain, CHECK_NULL);
2346 if (klass != NULL)
2347 return klass;
2348
2349 // Now look to see if it has been loaded elsewhere, and is subject to
2350 // a loader constraint that would require this loader to return the
2351 // klass that is already loaded.
2352 if (FieldType::is_array(class_name)) {
2353 // For array classes, their Klass*s are not kept in the
2354 // constraint table. The element Klass*s are.
2355 FieldArrayInfo fd;
2356 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2357 if (t != T_OBJECT) {
2358 klass = Universe::typeArrayKlassObj(t);
2359 } else {
2360 MutexLocker mu(SystemDictionary_lock, THREAD);
2361 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2362 }
2363 // If element class already loaded, allocate array klass
2364 if (klass != NULL) {
2365 klass = klass->array_klass_or_null(fd.dimension());
2366 }
2367 } else {
2368 MutexLocker mu(SystemDictionary_lock, THREAD);
2369 // Non-array classes are easy: simply check the constraint table.
2370 klass = constraints()->find_constrained_klass(class_name, class_loader);
2371 }
2372
2373 return klass;
2374 }
2375
2376
2377 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2378 Handle class_loader1,
2379 Handle class_loader2,
2380 Thread* THREAD) {
2381 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2382 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2383
2384 Symbol* constraint_name = NULL;
2385 if (!FieldType::is_array(class_name)) {
2386 constraint_name = class_name;
2387 } else {
2388 // For array classes, their Klass*s are not kept in the
2389 // constraint table. The element classes are.
2390 FieldArrayInfo fd;
2391 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2392 // primitive types always pass
2393 if (t != T_OBJECT) {
2394 return true;
2395 } else {
2396 constraint_name = fd.object_key();
2397 }
2398 }
2399 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2400 int d_index1 = dictionary()->hash_to_index(d_hash1);
2401
2402 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2403 int d_index2 = dictionary()->hash_to_index(d_hash2);
2404 {
2405 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2406
2407 // Better never do a GC while we're holding these oops
2408 NoSafepointVerifier nosafepoint;
2409
2410 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2411 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2412 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2413 klass2, class_loader2);
2414 }
2415 }
2416
2417 // Add entry to resolution error table to record the error when the first
2418 // attempt to resolve a reference to a class has failed.
2419 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2420 Symbol* error, Symbol* message) {
2421 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2422 int index = resolution_errors()->hash_to_index(hash);
2423 {
2424 MutexLocker ml(SystemDictionary_lock, Thread::current());
2425 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2426 }
2427 }
2428
2429 // Delete a resolution error for RedefineClasses for a constant pool is going away
2430 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2431 resolution_errors()->delete_entry(pool);
2432 }
2433
2434 // Lookup resolution error table. Returns error if found, otherwise NULL.
2435 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2436 Symbol** message) {
2437 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2438 int index = resolution_errors()->hash_to_index(hash);
2439 {
2440 MutexLocker ml(SystemDictionary_lock, Thread::current());
2441 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2442 if (entry != NULL) {
2443 *message = entry->message();
2444 return entry->error();
2445 } else {
2446 return NULL;
2447 }
2448 }
2449 }
2450
2451
2452 // Signature constraints ensure that callers and callees agree about
2453 // the meaning of type names in their signatures. This routine is the
2454 // intake for constraints. It collects them from several places:
2455 //
2456 // * LinkResolver::resolve_method (if check_access is true) requires
2457 // that the resolving class (the caller) and the defining class of
2458 // the resolved method (the callee) agree on each type in the
2459 // method's signature.
2460 //
2461 // * LinkResolver::resolve_interface_method performs exactly the same
2462 // checks.
2463 //
2464 // * LinkResolver::resolve_field requires that the constant pool
2465 // attempting to link to a field agree with the field's defining
2466 // class about the type of the field signature.
2467 //
2468 // * klassVtable::initialize_vtable requires that, when a class
2469 // overrides a vtable entry allocated by a superclass, that the
2470 // overriding method (i.e., the callee) agree with the superclass
2471 // on each type in the method's signature.
2472 //
2473 // * klassItable::initialize_itable requires that, when a class fills
2474 // in its itables, for each non-abstract method installed in an
2475 // itable, the method (i.e., the callee) agree with the interface
2476 // on each type in the method's signature.
2477 //
2478 // All those methods have a boolean (check_access, checkconstraints)
2479 // which turns off the checks. This is used from specialized contexts
2480 // such as bootstrapping, dumping, and debugging.
2481 //
2482 // No direct constraint is placed between the class and its
2483 // supertypes. Constraints are only placed along linked relations
2484 // between callers and callees. When a method overrides or implements
2485 // an abstract method in a supertype (superclass or interface), the
2486 // constraints are placed as if the supertype were the caller to the
2487 // overriding method. (This works well, since callers to the
2488 // supertype have already established agreement between themselves and
2489 // the supertype.) As a result of all this, a class can disagree with
2490 // its supertype about the meaning of a type name, as long as that
2491 // class neither calls a relevant method of the supertype, nor is
2492 // called (perhaps via an override) from the supertype.
2493 //
2494 //
2495 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2496 //
2497 // Make sure all class components (including arrays) in the given
2498 // signature will be resolved to the same class in both loaders.
2499 // Returns the name of the type that failed a loader constraint check, or
2500 // NULL if no constraint failed. No exception except OOME is thrown.
2501 // Arrays are not added to the loader constraint table, their elements are.
2502 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2503 Handle loader1, Handle loader2,
2504 bool is_method, TRAPS) {
2505 // Nothing to do if loaders are the same.
2506 if (loader1() == loader2()) {
2507 return NULL;
2508 }
2509
2510 SignatureStream sig_strm(signature, is_method);
2511 while (!sig_strm.is_done()) {
2512 if (sig_strm.is_object()) {
2513 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2514 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2515 return sig;
2516 }
2517 }
2518 sig_strm.next();
2519 }
2520 return NULL;
2521 }
2522
2523
2524 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2525 Symbol* signature,
2526 TRAPS) {
2527 methodHandle empty;
2528 assert(MethodHandles::is_signature_polymorphic(iid) &&
2529 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2530 iid != vmIntrinsics::_invokeGeneric,
2531 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2532
2533 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2534 int index = invoke_method_table()->hash_to_index(hash);
2535 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2536 methodHandle m;
2537 if (spe == NULL || spe->method() == NULL) {
2538 spe = NULL;
2539 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2540 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2541 if (!Arguments::is_interpreter_only()) {
2542 // Generate a compiled form of the MH intrinsic.
2543 AdapterHandlerLibrary::create_native_wrapper(m);
2544 // Check if have the compiled code.
2545 if (!m->has_compiled_code()) {
2546 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2547 "Out of space in CodeCache for method handle intrinsic", empty);
2548 }
2549 }
2550 // Now grab the lock. We might have to throw away the new method,
2551 // if a racing thread has managed to install one at the same time.
2552 {
2553 MutexLocker ml(SystemDictionary_lock, THREAD);
2554 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2555 if (spe == NULL)
2556 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2557 if (spe->method() == NULL)
2558 spe->set_method(m());
2559 }
2560 }
2561
2562 assert(spe != NULL && spe->method() != NULL, "");
2563 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2564 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2565 "MH intrinsic invariant");
2566 return spe->method();
2567 }
2568
2569 // Helper for unpacking the return value from linkMethod and linkCallSite.
2570 static methodHandle unpack_method_and_appendix(Handle mname,
2571 KlassHandle accessing_klass,
2572 objArrayHandle appendix_box,
2573 Handle* appendix_result,
2574 TRAPS) {
2575 methodHandle empty;
2576 if (mname.not_null()) {
2577 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2578 if (vmtarget != NULL && vmtarget->is_method()) {
2579 Method* m = (Method*)vmtarget;
2580 oop appendix = appendix_box->obj_at(0);
2581 if (TraceMethodHandles) {
2582 #ifndef PRODUCT
2583 ttyLocker ttyl;
2584 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2585 m->print();
2586 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2587 tty->cr();
2588 #endif //PRODUCT
2589 }
2590 (*appendix_result) = Handle(THREAD, appendix);
2591 // the target is stored in the cpCache and if a reference to this
2592 // MethodName is dropped we need a way to make sure the
2593 // class_loader containing this method is kept alive.
2594 // FIXME: the appendix might also preserve this dependency.
2595 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2596 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2597 return methodHandle(THREAD, m);
2598 }
2599 }
2600 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2601 return empty;
2602 }
2603
2604 methodHandle SystemDictionary::find_method_handle_invoker(KlassHandle klass,
2605 Symbol* name,
2606 Symbol* signature,
2607 KlassHandle accessing_klass,
2608 Handle *appendix_result,
2609 Handle *method_type_result,
2610 TRAPS) {
2611 methodHandle empty;
2612 assert(THREAD->can_call_java() ,"");
2613 Handle method_type =
2614 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2615
2616 int ref_kind = JVM_REF_invokeVirtual;
2617 oop name_oop = StringTable::intern(name, CHECK_(empty));
2618 Handle name_str (THREAD, name_oop);
2619 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2620 assert(appendix_box->obj_at(0) == NULL, "");
2621
2622 // This should not happen. JDK code should take care of that.
2623 if (accessing_klass.is_null() || method_type.is_null()) {
2624 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2625 }
2626
2627 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2628 JavaCallArguments args;
2629 args.push_oop(Handle(THREAD, accessing_klass()->java_mirror()));
2630 args.push_int(ref_kind);
2631 args.push_oop(Handle(THREAD, klass()->java_mirror()));
2632 args.push_oop(name_str);
2633 args.push_oop(method_type);
2634 args.push_oop(appendix_box);
2635 JavaValue result(T_OBJECT);
2636 JavaCalls::call_static(&result,
2637 SystemDictionary::MethodHandleNatives_klass(),
2638 vmSymbols::linkMethod_name(),
2639 vmSymbols::linkMethod_signature(),
2640 &args, CHECK_(empty));
2641 Handle mname(THREAD, (oop) result.get_jobject());
2642 (*method_type_result) = method_type;
2643 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2644 }
2645
2646 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2647 // We must ensure that all class loaders everywhere will reach this class, for any client.
2648 // This is a safe bet for public classes in java.lang, such as Object and String.
2649 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2650 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2651 static bool is_always_visible_class(oop mirror) {
2652 Klass* klass = java_lang_Class::as_Klass(mirror);
2653 if (klass->is_objArray_klass()) {
2654 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2655 }
2656 if (klass->is_typeArray_klass()) {
2657 return true; // primitive array
2658 }
2659 assert(klass->is_instance_klass(), "%s", klass->external_name());
2660 return klass->is_public() &&
2661 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2662 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2663 }
2664
2665 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2666 // signature, as interpreted relative to the given class loader.
2667 // Because of class loader constraints, all method handle usage must be
2668 // consistent with this loader.
2669 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2670 KlassHandle accessing_klass,
2671 TRAPS) {
2672 Handle empty;
2673 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2674 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2675 int index = invoke_method_table()->hash_to_index(hash);
2676 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2677 if (spe != NULL && spe->method_type() != NULL) {
2678 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2679 return Handle(THREAD, spe->method_type());
2680 } else if (!THREAD->can_call_java()) {
2681 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2682 return Handle(); // do not attempt from within compiler, unless it was cached
2683 }
2684
2685 Handle class_loader, protection_domain;
2686 if (accessing_klass.not_null()) {
2687 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2688 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2689 }
2690 bool can_be_cached = true;
2691 int npts = ArgumentCount(signature).size();
2692 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2693 int arg = 0;
2694 Handle rt; // the return type from the signature
2695 ResourceMark rm(THREAD);
2696 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2697 oop mirror = NULL;
2698 if (can_be_cached) {
2699 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2700 mirror = ss.as_java_mirror(Handle(), Handle(),
2701 SignatureStream::ReturnNull, CHECK_(empty));
2702 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2703 // Fall back to accessing_klass context.
2704 can_be_cached = false;
2705 }
2706 }
2707 if (!can_be_cached) {
2708 // Resolve, throwing a real error if it doesn't work.
2709 mirror = ss.as_java_mirror(class_loader, protection_domain,
2710 SignatureStream::NCDFError, CHECK_(empty));
2711 }
2712 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2713 if (ss.at_return_type())
2714 rt = Handle(THREAD, mirror);
2715 else
2716 pts->obj_at_put(arg++, mirror);
2717
2718 // Check accessibility.
2719 if (ss.is_object() && accessing_klass.not_null()) {
2720 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2721 mirror = NULL; // safety
2722 // Emulate ConstantPool::verify_constant_pool_resolve.
2723 if (sel_klass->is_objArray_klass())
2724 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2725 if (sel_klass->is_instance_klass()) {
2726 KlassHandle sel_kh(THREAD, sel_klass);
2727 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2728 }
2729 }
2730 }
2731 assert(arg == npts, "");
2732
2733 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2734 JavaCallArguments args(Handle(THREAD, rt()));
2735 args.push_oop(pts);
2736 JavaValue result(T_OBJECT);
2737 JavaCalls::call_static(&result,
2738 SystemDictionary::MethodHandleNatives_klass(),
2739 vmSymbols::findMethodHandleType_name(),
2740 vmSymbols::findMethodHandleType_signature(),
2741 &args, CHECK_(empty));
2742 Handle method_type(THREAD, (oop) result.get_jobject());
2743
2744 if (can_be_cached) {
2745 // We can cache this MethodType inside the JVM.
2746 MutexLocker ml(SystemDictionary_lock, THREAD);
2747 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2748 if (spe == NULL)
2749 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2750 if (spe->method_type() == NULL) {
2751 spe->set_method_type(method_type());
2752 }
2753 }
2754
2755 // report back to the caller with the MethodType
2756 return method_type;
2757 }
2758
2759 // Ask Java code to find or construct a method handle constant.
2760 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2761 int ref_kind, //e.g., JVM_REF_invokeVirtual
2762 KlassHandle callee,
2763 Symbol* name_sym,
2764 Symbol* signature,
2765 TRAPS) {
2766 Handle empty;
2767 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2768 Handle type;
2769 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2770 type = find_method_handle_type(signature, caller, CHECK_(empty));
2771 } else if (caller.is_null()) {
2772 // This should not happen. JDK code should take care of that.
2773 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2774 } else {
2775 ResourceMark rm(THREAD);
2776 SignatureStream ss(signature, false);
2777 if (!ss.is_done()) {
2778 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2779 Handle(THREAD, caller->protection_domain()),
2780 SignatureStream::NCDFError, CHECK_(empty));
2781 type = Handle(THREAD, mirror);
2782 ss.next();
2783 if (!ss.is_done()) type = Handle(); // error!
2784 }
2785 }
2786 if (type.is_null()) {
2787 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2788 }
2789
2790 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2791 JavaCallArguments args;
2792 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2793 args.push_int(ref_kind);
2794 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2795 args.push_oop(name);
2796 args.push_oop(type);
2797 JavaValue result(T_OBJECT);
2798 JavaCalls::call_static(&result,
2799 SystemDictionary::MethodHandleNatives_klass(),
2800 vmSymbols::linkMethodHandleConstant_name(),
2801 vmSymbols::linkMethodHandleConstant_signature(),
2802 &args, CHECK_(empty));
2803 return Handle(THREAD, (oop) result.get_jobject());
2804 }
2805
2806 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2807 // name and signature, as interpreted relative to the given class loader.
2808 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2809 Handle bootstrap_specifier,
2810 Symbol* name,
2811 Symbol* type,
2812 Handle *appendix_result,
2813 Handle *method_type_result,
2814 TRAPS) {
2815 methodHandle empty;
2816 Handle bsm, info;
2817 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2818 bsm = bootstrap_specifier;
2819 } else {
2820 assert(bootstrap_specifier->is_objArray(), "");
2821 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2822 int len = args->length();
2823 assert(len >= 1, "");
2824 bsm = Handle(THREAD, args->obj_at(0));
2825 if (len > 1) {
2826 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2827 for (int i = 1; i < len; i++)
2828 args1->obj_at_put(i-1, args->obj_at(i));
2829 info = Handle(THREAD, args1);
2830 }
2831 }
2832 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2833 "caller must supply a valid BSM");
2834
2835 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2836 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2837
2838 // This should not happen. JDK code should take care of that.
2839 if (caller.is_null() || method_type.is_null()) {
2840 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2841 }
2842
2843 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2844 assert(appendix_box->obj_at(0) == NULL, "");
2845
2846 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2847 JavaCallArguments args;
2848 args.push_oop(Handle(THREAD, caller->java_mirror()));
2849 args.push_oop(bsm);
2850 args.push_oop(method_name);
2851 args.push_oop(method_type);
2852 args.push_oop(info);
2853 args.push_oop(appendix_box);
2854 JavaValue result(T_OBJECT);
2855 JavaCalls::call_static(&result,
2856 SystemDictionary::MethodHandleNatives_klass(),
2857 vmSymbols::linkCallSite_name(),
2858 vmSymbols::linkCallSite_signature(),
2859 &args, CHECK_(empty));
2860 Handle mname(THREAD, (oop) result.get_jobject());
2861 (*method_type_result) = method_type;
2862 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2863 }
2864
2865 // Since the identity hash code for symbols changes when the symbols are
2866 // moved from the regular perm gen (hash in the mark word) to the shared
2867 // spaces (hash is the address), the classes loaded into the dictionary
2868 // may be in the wrong buckets.
2869
2870 void SystemDictionary::reorder_dictionary() {
2871 dictionary()->reorder_dictionary();
2872 }
2873
2874
2875 void SystemDictionary::copy_buckets(char** top, char* end) {
2876 dictionary()->copy_buckets(top, end);
2877 }
2878
2879
2880 void SystemDictionary::copy_table(char** top, char* end) {
2881 dictionary()->copy_table(top, end);
2882 }
2883
2884
2885 void SystemDictionary::reverse() {
2886 dictionary()->reverse();
2887 }
2888
2889 int SystemDictionary::number_of_classes() {
2890 return dictionary()->number_of_entries();
2891 }
2892
2893
2894 // ----------------------------------------------------------------------------
2895 void SystemDictionary::print_shared(bool details) {
2896 shared_dictionary()->print(details);
2897 }
2898
2899 void SystemDictionary::print(bool details) {
2900 dictionary()->print(details);
2901
2902 // Placeholders
2903 GCMutexLocker mu(SystemDictionary_lock);
2904 placeholders()->print();
2905
2906 // loader constraints - print under SD_lock
2907 constraints()->print();
2908 }
2909
2910
2911 void SystemDictionary::verify() {
2912 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2913 guarantee(constraints() != NULL,
2914 "Verify of loader constraints failed");
2915 guarantee(dictionary()->number_of_entries() >= 0 &&
2916 placeholders()->number_of_entries() >= 0,
2917 "Verify of system dictionary failed");
2918
2919 // Verify dictionary
2920 dictionary()->verify();
2921
2922 GCMutexLocker mu(SystemDictionary_lock);
2923 placeholders()->verify();
2924
2925 // Verify constraint table
2926 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2927 constraints()->verify(dictionary(), placeholders());
2928 }
2929
2930 // caller needs ResourceMark
2931 const char* SystemDictionary::loader_name(const oop loader) {
2932 return ((loader) == NULL ? "<bootloader>" :
2933 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2934 }
2935
2936 // caller needs ResourceMark
2937 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2938 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2939 SystemDictionary::loader_name(loader_data->class_loader()));
2940 }
--- EOF ---