1 /*
2 * Copyright (c) 1997, 2018, 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 "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "gc/shared/oopStorage.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "jfr/jfrEvents.hpp"
51 #include "logging/log.hpp"
52 #include "logging/logStream.hpp"
53 #include "memory/filemap.hpp"
54 #include "memory/metaspaceClosure.hpp"
55 #include "memory/oopFactory.hpp"
56 #include "memory/resourceArea.hpp"
57 #include "oops/access.inline.hpp"
58 #include "oops/instanceKlass.hpp"
59 #include "oops/instanceRefKlass.hpp"
60 #include "oops/klass.inline.hpp"
61 #include "oops/method.inline.hpp"
62 #include "oops/methodData.hpp"
63 #include "oops/objArrayKlass.hpp"
64 #include "oops/objArrayOop.inline.hpp"
65 #include "oops/oop.inline.hpp"
66 #include "oops/symbol.hpp"
67 #include "oops/typeArrayKlass.hpp"
68 #include "prims/jvmtiEnvBase.hpp"
69 #include "prims/resolvedMethodTable.hpp"
70 #include "prims/methodHandles.hpp"
71 #include "runtime/arguments.hpp"
72 #include "runtime/arguments_ext.hpp"
73 #include "runtime/biasedLocking.hpp"
74 #include "runtime/fieldType.hpp"
75 #include "runtime/handles.inline.hpp"
76 #include "runtime/java.hpp"
77 #include "runtime/javaCalls.hpp"
78 #include "runtime/mutexLocker.hpp"
79 #include "runtime/orderAccess.hpp"
80 #include "runtime/sharedRuntime.hpp"
81 #include "runtime/signature.hpp"
82 #include "services/classLoadingService.hpp"
83 #include "services/diagnosticCommand.hpp"
84 #include "services/threadService.hpp"
85 #include "utilities/macros.hpp"
86 #if INCLUDE_CDS
87 #include "classfile/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_checkPackageAccess = false;
112
113 // Default ProtectionDomainCacheSize value
114
115 const int defaultProtectionDomainCacheSize = 1009;
116
117 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149 }
150
151 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
152 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
153 return ClassLoaderDataGraph::find_or_create(class_loader);
154 }
155
156 // ----------------------------------------------------------------------------
157 // Parallel class loading check
158
159 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
160 if (class_loader.is_null()) return true;
161 if (AlwaysLockClassLoader) return false;
162 return java_lang_ClassLoader::parallelCapable(class_loader());
163 }
164 // ----------------------------------------------------------------------------
165 // ParallelDefineClass flag does not apply to bootclass loader
166 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
167 if (class_loader.is_null()) return false;
168 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
169 return true;
170 }
171 return false;
172 }
173
174 // Returns true if the passed class loader is the builtin application class loader
175 // or a custom system class loader. A customer system class loader can be
176 // specified via -Djava.system.class.loader.
177 bool SystemDictionary::is_system_class_loader(oop class_loader) {
178 if (class_loader == NULL) {
179 return false;
180 }
181 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
182 oopDesc::equals(class_loader, _java_system_loader));
183 }
184
185 // Returns true if the passed class loader is the platform class loader.
186 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
187 if (class_loader == NULL) {
188 return false;
189 }
190 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
191 }
192
193 // ----------------------------------------------------------------------------
194 // Resolving of classes
195
196 // Forwards to resolve_or_null
197
198 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
199 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
200 if (HAS_PENDING_EXCEPTION || klass == NULL) {
201 // can return a null klass
202 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
203 }
204 return klass;
205 }
206
207 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
208 bool throw_error,
209 Klass* klass, TRAPS) {
210 if (HAS_PENDING_EXCEPTION) {
211 // If we have a pending exception we forward it to the caller, unless throw_error is true,
212 // in which case we have to check whether the pending exception is a ClassNotFoundException,
213 // and if so convert it to a NoClassDefFoundError
214 // And chain the original ClassNotFoundException
215 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
216 ResourceMark rm(THREAD);
217 assert(klass == NULL, "Should not have result with exception pending");
218 Handle e(THREAD, PENDING_EXCEPTION);
219 CLEAR_PENDING_EXCEPTION;
220 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
221 } else {
222 return NULL;
223 }
224 }
225 // Class not found, throw appropriate error or exception depending on value of throw_error
226 if (klass == NULL) {
227 ResourceMark rm(THREAD);
228 if (throw_error) {
229 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
230 } else {
231 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
232 }
233 }
234 return klass;
235 }
236
237
238 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
239 bool throw_error, TRAPS)
240 {
241 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
242 }
243
244
245 // Forwards to resolve_instance_class_or_null
246
247 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
248 if (FieldType::is_array(class_name)) {
249 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
250 } else if (FieldType::is_obj(class_name)) {
251 ResourceMark rm(THREAD);
252 // Ignore wrapping L and ;.
253 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
254 class_name->utf8_length() - 2, CHECK_NULL);
255 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
256 } else {
257 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
258 }
259 }
260
261 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
262 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
263 }
264
265 // Forwards to resolve_instance_class_or_null
266
267 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
268 Handle class_loader,
269 Handle protection_domain,
270 TRAPS) {
271 assert(FieldType::is_array(class_name), "must be array");
272 Klass* k = NULL;
273 FieldArrayInfo fd;
274 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
275 // of this call
276 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
277 if (t == T_OBJECT) {
278 // naked oop "k" is OK here -- we assign back into it
279 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
280 class_loader,
281 protection_domain,
282 CHECK_NULL);
283 if (k != NULL) {
284 k = k->array_klass(fd.dimension(), CHECK_NULL);
285 }
286 } else {
287 k = Universe::typeArrayKlassObj(t);
288 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
289 }
290 return k;
291 }
292
293
294 // Must be called for any super-class or super-interface resolution
295 // during class definition to allow class circularity checking
296 // super-interface callers:
297 // parse_interfaces - for defineClass & jvmtiRedefineClasses
298 // super-class callers:
299 // ClassFileParser - for defineClass & jvmtiRedefineClasses
300 // load_shared_class - while loading a class from shared archive
301 // resolve_instance_class_or_null:
302 // via: handle_parallel_super_load
303 // when resolving a class that has an existing placeholder with
304 // a saved superclass [i.e. a defineClass is currently in progress]
305 // if another thread is trying to resolve the class, it must do
306 // super-class checks on its own thread to catch class circularity
307 // This last call is critical in class circularity checking for cases
308 // where classloading is delegated to different threads and the
309 // classloader lock is released.
310 // Take the case: Base->Super->Base
311 // 1. If thread T1 tries to do a defineClass of class Base
312 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
313 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
314 // so it tries to load Super
315 // 3. If we load the class internally, or user classloader uses same thread
316 // loadClassFromxxx or defineClass via parseClassFile Super ...
317 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
318 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
319 // 3.4 calls resolve_super_or_fail Base
320 // 3.5 finds T1,Base -> throws class circularity
321 //OR 4. If T2 tries to resolve Super via defineClass Super ...
322 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
323 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
324 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
325 // 4.4 finds T2, Super -> throws class circularity
326 // Must be called, even if superclass is null, since this is
327 // where the placeholder entry is created which claims this
328 // thread is loading this class/classloader.
329 // Be careful when modifying this code: once you have run
330 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
331 // you need to find_and_remove it before returning.
332 // So be careful to not exit with a CHECK_ macro betweeen these calls.
333 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
334 Symbol* class_name,
335 Handle class_loader,
336 Handle protection_domain,
337 bool is_superclass,
338 TRAPS) {
339 #if INCLUDE_CDS
340 if (DumpSharedSpaces) {
341 // Special processing for CDS dump time.
342 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
343 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
344 if (k) {
345 return k;
346 }
347 }
348 #endif // INCLUDE_CDS
349
350 // Double-check, if child class is already loaded, just return super-class,interface
351 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
352 // dictionary.
353 // Make sure there's a placeholder for the *child* before resolving.
354 // Used as a claim that this thread is currently loading superclass/classloader
355 // Used here for ClassCircularity checks and also for heap verification
356 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
357 // Must check ClassCircularity before checking if super class is already loaded.
358 //
359 // We might not already have a placeholder if this child_name was
360 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
361 // the name of the class might not be known until the stream is actually
362 // parsed.
363 // Bugs 4643874, 4715493
364
365 ClassLoaderData* loader_data = class_loader_data(class_loader);
366 Dictionary* dictionary = loader_data->dictionary();
367 unsigned int d_hash = dictionary->compute_hash(child_name);
368 unsigned int p_hash = placeholders()->compute_hash(child_name);
369 int p_index = placeholders()->hash_to_index(p_hash);
370 // can't throw error holding a lock
371 bool child_already_loaded = false;
372 bool throw_circularity_error = false;
373 {
374 MutexLocker mu(SystemDictionary_lock, THREAD);
375 Klass* childk = find_class(d_hash, child_name, dictionary);
376 Klass* quicksuperk;
377 // to support // loading: if child done loading, just return superclass
378 // if class_name, & class_loader don't match:
379 // if initial define, SD update will give LinkageError
380 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
381 // so we don't throw an exception here.
382 // see: nsk redefclass014 & java.lang.instrument Instrument032
383 if ((childk != NULL ) && (is_superclass) &&
384 ((quicksuperk = childk->super()) != NULL) &&
385
386 ((quicksuperk->name() == class_name) &&
387 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
388 return quicksuperk;
389 } else {
390 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
391 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
392 throw_circularity_error = true;
393 }
394 }
395 if (!throw_circularity_error) {
396 // Be careful not to exit resolve_super
397 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
398 }
399 }
400 if (throw_circularity_error) {
401 ResourceMark rm(THREAD);
402 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
403 }
404
405 // java.lang.Object should have been found above
406 assert(class_name != NULL, "null super class for resolving");
407 // Resolve the super class or interface, check results on return
408 Klass* superk = SystemDictionary::resolve_or_null(class_name,
409 class_loader,
410 protection_domain,
411 THREAD);
412
413 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
414 // It is no longer necessary to keep the placeholder table alive until update_dictionary
415 // or error. GC used to walk the placeholder table as strong roots.
416 // The instanceKlass is kept alive because the class loader is on the stack,
417 // which keeps the loader_data alive, as well as all instanceKlasses in
418 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
419 {
420 MutexLocker mu(SystemDictionary_lock, THREAD);
421 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
422 SystemDictionary_lock->notify_all();
423 }
424 if (HAS_PENDING_EXCEPTION || superk == NULL) {
425 // can null superk
426 superk = handle_resolution_exception(class_name, true, superk, THREAD);
427 }
428
429 return superk;
430 }
431
432 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
433 Handle class_loader,
434 Handle protection_domain,
435 TRAPS) {
436 if(!has_checkPackageAccess()) return;
437
438 // Now we have to call back to java to check if the initating class has access
439 JavaValue result(T_VOID);
440 LogTarget(Debug, protectiondomain) lt;
441 if (lt.is_enabled()) {
442 ResourceMark rm;
443 // Print out trace information
444 LogStream ls(lt);
445 ls.print_cr("Checking package access");
446 ls.print("class loader: "); class_loader()->print_value_on(&ls);
447 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
448 ls.print(" loading: "); klass->print_value_on(&ls);
449 ls.cr();
450 }
451
452 // This handle and the class_loader handle passed in keeps this class from
453 // being unloaded through several GC points.
454 // The class_loader handle passed in is the initiating loader.
455 Handle mirror(THREAD, klass->java_mirror());
456
457 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
458 JavaCalls::call_special(&result,
459 class_loader,
460 system_loader,
461 vmSymbols::checkPackageAccess_name(),
462 vmSymbols::class_protectiondomain_signature(),
463 mirror,
464 protection_domain,
465 THREAD);
466
467 if (HAS_PENDING_EXCEPTION) {
468 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
469 } else {
470 log_debug(protectiondomain)("granted");
471 }
472
473 if (HAS_PENDING_EXCEPTION) return;
474
475 // If no exception has been thrown, we have validated the protection domain
476 // Insert the protection domain of the initiating class into the set.
477 {
478 ClassLoaderData* loader_data = class_loader_data(class_loader);
479 Dictionary* dictionary = loader_data->dictionary();
480
481 Symbol* kn = klass->name();
482 unsigned int d_hash = dictionary->compute_hash(kn);
483
484 MutexLocker mu(SystemDictionary_lock, THREAD);
485 int d_index = dictionary->hash_to_index(d_hash);
486 dictionary->add_protection_domain(d_index, d_hash, klass,
487 protection_domain, THREAD);
488 }
489 }
490
491 // We only get here if this thread finds that another thread
492 // has already claimed the placeholder token for the current operation,
493 // but that other thread either never owned or gave up the
494 // object lock
495 // Waits on SystemDictionary_lock to indicate placeholder table updated
496 // On return, caller must recheck placeholder table state
497 //
498 // We only get here if
499 // 1) custom classLoader, i.e. not bootstrap classloader
500 // 2) 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((!oopDesc::equals(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 InstanceKlass* SystemDictionary::handle_parallel_super_load(
544 Symbol* name, Symbol* superclassname, Handle class_loader,
545 Handle protection_domain, Handle lockObject, TRAPS) {
546
547 ClassLoaderData* loader_data = class_loader_data(class_loader);
548 Dictionary* dictionary = loader_data->dictionary();
549 unsigned int d_hash = dictionary->compute_hash(name);
550 unsigned int p_hash = placeholders()->compute_hash(name);
551 int p_index = placeholders()->hash_to_index(p_hash);
552
553 // superk is not used, resolve_super called for circularity check only
554 // This code is reached in two situations. One if this thread
555 // is loading the same class twice (e.g. ClassCircularity, or
556 // java.lang.instrument).
557 // The second is if another thread started the resolve_super first
558 // and has not yet finished.
559 // In both cases the original caller will clean up the placeholder
560 // entry on error.
561 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
562 superclassname,
563 class_loader,
564 protection_domain,
565 true,
566 CHECK_NULL);
567
568 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
569 // Serial class loaders and bootstrap classloader do wait for superclass loads
570 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
571 MutexLocker mu(SystemDictionary_lock, THREAD);
572 // Check if classloading completed while we were loading superclass or waiting
573 return find_class(d_hash, name, dictionary);
574 }
575
576 // must loop to both handle other placeholder updates
577 // and spurious notifications
578 bool super_load_in_progress = true;
579 PlaceholderEntry* placeholder;
580 while (super_load_in_progress) {
581 MutexLocker mu(SystemDictionary_lock, THREAD);
582 // Check if classloading completed while we were loading superclass or waiting
583 InstanceKlass* check = find_class(d_hash, name, dictionary);
584 if (check != NULL) {
585 // Klass is already loaded, so just return it
586 return check;
587 } else {
588 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
589 if (placeholder && placeholder->super_load_in_progress() ){
590 // We only get here if the application has released the
591 // classloader lock when another thread was in the middle of loading a
592 // superclass/superinterface for this class, and now
593 // this thread is also trying to load this class.
594 // To minimize surprises, the first thread that started to
595 // load a class should be the one to complete the loading
596 // with the classfile it initially expected.
597 // This logic has the current thread wait once it has done
598 // all the superclass/superinterface loading it can, until
599 // the original thread completes the class loading or fails
600 // If it completes we will use the resulting InstanceKlass
601 // which we will find below in the systemDictionary.
602 // We also get here for parallel bootstrap classloader
603 if (class_loader.is_null()) {
604 SystemDictionary_lock->wait();
605 } else {
606 double_lock_wait(lockObject, THREAD);
607 }
608 } else {
609 // If not in SD and not in PH, other thread's load must have failed
610 super_load_in_progress = false;
611 }
612 }
613 }
614 return NULL;
615 }
616
617 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
618 assert(event != NULL, "invariant");
619 assert(k != NULL, "invariant");
620 assert(event->should_commit(), "invariant");
621 event->set_loadedClass(k);
622 event->set_definingClassLoader(k->class_loader_data());
623 event->set_initiatingClassLoader(init_cld);
624 event->commit();
625 }
626
627
628 // Be careful when modifying this code: once you have run
629 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
630 // you need to find_and_remove it before returning.
631 // So be careful to not exit with a CHECK_ macro betweeen these calls.
632 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
633 Handle class_loader,
634 Handle protection_domain,
635 TRAPS) {
636 assert(name != NULL && !FieldType::is_array(name) &&
637 !FieldType::is_obj(name), "invalid class name");
638
639 EventClassLoad class_load_start_event;
640
641 HandleMark hm(THREAD);
642
643 // Fix for 4474172; see evaluation for more details
644 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
645 ClassLoaderData* loader_data = register_loader(class_loader);
646 Dictionary* dictionary = loader_data->dictionary();
647 unsigned int d_hash = dictionary->compute_hash(name);
648
649 // Do lookup to see if class already exist and the protection domain
650 // has the right access
651 // This call uses find which checks protection domain already matches
652 // All subsequent calls use find_class, and set has_loaded_class so that
653 // before we return a result we call out to java to check for valid protection domain
654 // to allow returning the Klass* and add it to the pd_set if it is valid
655 {
656 Klass* probe = dictionary->find(d_hash, name, protection_domain);
657 if (probe != NULL) return probe;
658 }
659
660 // Non-bootstrap class loaders will call out to class loader and
661 // define via jvm/jni_DefineClass which will acquire the
662 // class loader object lock to protect against multiple threads
663 // defining the class in parallel by accident.
664 // This lock must be acquired here so the waiter will find
665 // any successful result in the SystemDictionary and not attempt
666 // the define.
667 // ParallelCapable Classloaders and the bootstrap classloader
668 // do not acquire lock here.
669 bool DoObjectLock = true;
670 if (is_parallelCapable(class_loader)) {
671 DoObjectLock = false;
672 }
673
674 unsigned int p_hash = placeholders()->compute_hash(name);
675 int p_index = placeholders()->hash_to_index(p_hash);
676
677 // Class is not in SystemDictionary so we have to do loading.
678 // Make sure we are synchronized on the class loader before we proceed
679 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
680 check_loader_lock_contention(lockObject, THREAD);
681 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
682
683 // Check again (after locking) if class already exist in SystemDictionary
684 bool class_has_been_loaded = false;
685 bool super_load_in_progress = false;
686 bool havesupername = false;
687 InstanceKlass* k = NULL;
688 PlaceholderEntry* placeholder;
689 Symbol* superclassname = NULL;
690
691 assert(THREAD->can_call_java(),
692 "can not load classes with compiler thread: class=%s, classloader=%s",
693 name->as_C_string(),
694 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
695 {
696 MutexLocker mu(SystemDictionary_lock, THREAD);
697 InstanceKlass* check = find_class(d_hash, name, dictionary);
698 if (check != NULL) {
699 // Klass is already loaded, so just return it
700 class_has_been_loaded = true;
701 k = check;
702 } else {
703 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
704 if (placeholder && placeholder->super_load_in_progress()) {
705 super_load_in_progress = true;
706 if (placeholder->havesupername() == true) {
707 superclassname = placeholder->supername();
708 havesupername = true;
709 }
710 }
711 }
712 }
713
714 // If the class is in the placeholder table, class loading is in progress
715 if (super_load_in_progress && havesupername==true) {
716 k = handle_parallel_super_load(name,
717 superclassname,
718 class_loader,
719 protection_domain,
720 lockObject, THREAD);
721 if (HAS_PENDING_EXCEPTION) {
722 return NULL;
723 }
724 if (k != NULL) {
725 class_has_been_loaded = true;
726 }
727 }
728
729 bool throw_circularity_error = false;
730 if (!class_has_been_loaded) {
731 bool load_instance_added = false;
732
733 // add placeholder entry to record loading instance class
734 // Five cases:
735 // All cases need to prevent modifying bootclasssearchpath
736 // in parallel with a classload of same classname
737 // Redefineclasses uses existence of the placeholder for the duration
738 // of the class load to prevent concurrent redefinition of not completely
739 // defined classes.
740 // case 1. traditional classloaders that rely on the classloader object lock
741 // - no other need for LOAD_INSTANCE
742 // case 2. traditional classloaders that break the classloader object lock
743 // as a deadlock workaround. Detection of this case requires that
744 // this check is done while holding the classloader object lock,
745 // and that lock is still held when calling classloader's loadClass.
746 // For these classloaders, we ensure that the first requestor
747 // completes the load and other requestors wait for completion.
748 // case 3. Bootstrap classloader - don't own objectLocker
749 // This classloader supports parallelism at the classloader level,
750 // but only allows a single load of a class/classloader pair.
751 // No performance benefit and no deadlock issues.
752 // case 4. parallelCapable user level classloaders - without objectLocker
753 // Allow parallel classloading of a class/classloader pair
754
755 {
756 MutexLocker mu(SystemDictionary_lock, THREAD);
757 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
758 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
759 if (oldprobe) {
760 // only need check_seen_thread once, not on each loop
761 // 6341374 java/lang/Instrument with -Xcomp
762 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
763 throw_circularity_error = true;
764 } else {
765 // case 1: traditional: should never see load_in_progress.
766 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
767
768 // case 3: bootstrap classloader: prevent futile classloading,
769 // wait on first requestor
770 if (class_loader.is_null()) {
771 SystemDictionary_lock->wait();
772 } else {
773 // case 2: traditional with broken classloader lock. wait on first
774 // requestor.
775 double_lock_wait(lockObject, THREAD);
776 }
777 // Check if classloading completed while we were waiting
778 InstanceKlass* check = find_class(d_hash, name, dictionary);
779 if (check != NULL) {
780 // Klass is already loaded, so just return it
781 k = check;
782 class_has_been_loaded = true;
783 }
784 // check if other thread failed to load and cleaned up
785 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
786 }
787 }
788 }
789 }
790 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
791 // case 4: parallelCapable: allow competing threads to try
792 // LOAD_INSTANCE in parallel
793
794 if (!throw_circularity_error && !class_has_been_loaded) {
795 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
796 load_instance_added = true;
797 // For class loaders that do not acquire the classloader object lock,
798 // if they did not catch another thread holding LOAD_INSTANCE,
799 // need a check analogous to the acquire ObjectLocker/find_class
800 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
801 // one final check if the load has already completed
802 // class loaders holding the ObjectLock shouldn't find the class here
803 InstanceKlass* check = find_class(d_hash, name, dictionary);
804 if (check != NULL) {
805 // Klass is already loaded, so return it after checking/adding protection domain
806 k = check;
807 class_has_been_loaded = true;
808 }
809 }
810 }
811
812 // must throw error outside of owning lock
813 if (throw_circularity_error) {
814 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
815 ResourceMark rm(THREAD);
816 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
817 }
818
819 if (!class_has_been_loaded) {
820
821 // Do actual loading
822 k = load_instance_class(name, class_loader, THREAD);
823
824 // If everything was OK (no exceptions, no null return value), and
825 // class_loader is NOT the defining loader, do a little more bookkeeping.
826 if (!HAS_PENDING_EXCEPTION && k != NULL &&
827 !oopDesc::equals(k->class_loader(), class_loader())) {
828
829 check_constraints(d_hash, k, class_loader, false, THREAD);
830
831 // Need to check for a PENDING_EXCEPTION again; check_constraints
832 // can throw but we may have to remove entry from the placeholder table below.
833 if (!HAS_PENDING_EXCEPTION) {
834 // Record dependency for non-parent delegation.
835 // This recording keeps the defining class loader of the klass (k) found
836 // from being unloaded while the initiating class loader is loaded
837 // even if the reference to the defining class loader is dropped
838 // before references to the initiating class loader.
839 loader_data->record_dependency(k);
840
841 { // Grabbing the Compile_lock prevents systemDictionary updates
842 // during compilations.
843 MutexLocker mu(Compile_lock, THREAD);
844 update_dictionary(d_hash, p_index, p_hash,
845 k, class_loader, THREAD);
846 }
847
848 if (JvmtiExport::should_post_class_load()) {
849 Thread *thread = THREAD;
850 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
851 JvmtiExport::post_class_load((JavaThread *) thread, k);
852 }
853 }
854 }
855 } // load_instance_class
856
857 if (load_instance_added == true) {
858 // clean up placeholder entries for LOAD_INSTANCE success or error
859 // This brackets the SystemDictionary updates for both defining
860 // and initiating loaders
861 MutexLocker mu(SystemDictionary_lock, THREAD);
862 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
863 SystemDictionary_lock->notify_all();
864 }
865 }
866
867 if (HAS_PENDING_EXCEPTION || k == NULL) {
868 return NULL;
869 }
870 if (class_load_start_event.should_commit()) {
871 post_class_load_event(&class_load_start_event, k, loader_data);
872 }
873 #ifdef ASSERT
874 {
875 ClassLoaderData* loader_data = k->class_loader_data();
876 MutexLocker mu(SystemDictionary_lock, THREAD);
877 Klass* kk = find_class(name, loader_data);
878 assert(kk == k, "should be present in dictionary");
879 }
880 #endif
881
882 // return if the protection domain in NULL
883 if (protection_domain() == NULL) return k;
884
885 // Check the protection domain has the right access
886 if (dictionary->is_valid_protection_domain(d_hash, name,
887 protection_domain)) {
888 return k;
889 }
890
891 // Verify protection domain. If it fails an exception is thrown
892 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
893
894 return k;
895 }
896
897
898 // This routine does not lock the system dictionary.
899 //
900 // Since readers don't hold a lock, we must make sure that system
901 // dictionary entries are only removed at a safepoint (when only one
902 // thread is running), and are added to in a safe way (all links must
903 // be updated in an MT-safe manner).
904 //
905 // Callers should be aware that an entry could be added just after
906 // _dictionary->bucket(index) is read here, so the caller will not see
907 // the new entry.
908
909 Klass* SystemDictionary::find(Symbol* class_name,
910 Handle class_loader,
911 Handle protection_domain,
912 TRAPS) {
913
914 // The result of this call should be consistent with the result
915 // of the call to resolve_instance_class_or_null().
916 // See evaluation 6790209 and 4474172 for more details.
917 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
918 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
919
920 if (loader_data == NULL) {
921 // If the ClassLoaderData has not been setup,
922 // then the class loader has no entries in the dictionary.
923 return NULL;
924 }
925
926 Dictionary* dictionary = loader_data->dictionary();
927 unsigned int d_hash = dictionary->compute_hash(class_name);
928 return dictionary->find(d_hash, class_name,
929 protection_domain);
930 }
931
932
933 // Look for a loaded instance or array klass by name. Do not do any loading.
934 // return NULL in case of error.
935 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
936 Handle class_loader,
937 Handle protection_domain,
938 TRAPS) {
939 Klass* k = NULL;
940 assert(class_name != NULL, "class name must be non NULL");
941
942 if (FieldType::is_array(class_name)) {
943 // The name refers to an array. Parse the name.
944 // dimension and object_key in FieldArrayInfo are assigned as a
945 // side-effect of this call
946 FieldArrayInfo fd;
947 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
948 if (t != T_OBJECT) {
949 k = Universe::typeArrayKlassObj(t);
950 } else {
951 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
952 }
953 if (k != NULL) {
954 k = k->array_klass_or_null(fd.dimension());
955 }
956 } else {
957 k = find(class_name, class_loader, protection_domain, THREAD);
958 }
959 return k;
960 }
961
962 // Note: this method is much like resolve_from_stream, but
963 // does not publish the classes via the SystemDictionary.
964 // Handles unsafe_DefineAnonymousClass and redefineclasses
965 // RedefinedClasses do not add to the class hierarchy
966 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
967 Handle class_loader,
968 Handle protection_domain,
969 ClassFileStream* st,
970 const InstanceKlass* host_klass,
971 GrowableArray<Handle>* cp_patches,
972 TRAPS) {
973
974 EventClassLoad class_load_start_event;
975
976 ClassLoaderData* loader_data;
977 if (host_klass != NULL) {
978 // Create a new CLD for anonymous class, that uses the same class loader
979 // as the host_klass
980 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
981 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
982 } else {
983 loader_data = ClassLoaderData::class_loader_data(class_loader());
984 }
985
986 assert(st != NULL, "invariant");
987 assert(st->need_verify(), "invariant");
988
989 // Parse stream and create a klass.
990 // Note that we do this even though this klass might
991 // already be present in the SystemDictionary, otherwise we would not
992 // throw potential ClassFormatErrors.
993
994 InstanceKlass* k = KlassFactory::create_from_stream(st,
995 class_name,
996 loader_data,
997 protection_domain,
998 host_klass,
999 cp_patches,
1000 CHECK_NULL);
1001
1002 if (host_klass != NULL && k != NULL) {
1003 // Anonymous classes must update ClassLoaderData holder (was host_klass loader)
1004 // so that they can be unloaded when the mirror is no longer referenced.
1005 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1006
1007 {
1008 MutexLocker mu_r(Compile_lock, THREAD);
1009
1010 // Add to class hierarchy, initialize vtables, and do possible
1011 // deoptimizations.
1012 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1013
1014 // But, do not add to dictionary.
1015
1016 // compiled code dependencies need to be validated anyway
1017 notice_modification();
1018 }
1019
1020 // Rewrite and patch constant pool here.
1021 k->link_class(CHECK_NULL);
1022 if (cp_patches != NULL) {
1023 k->constants()->patch_resolved_references(cp_patches);
1024 }
1025
1026 // If it's anonymous, initialize it now, since nobody else will.
1027 k->eager_initialize(CHECK_NULL);
1028
1029 // notify jvmti
1030 if (JvmtiExport::should_post_class_load()) {
1031 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1032 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1033 }
1034 if (class_load_start_event.should_commit()) {
1035 post_class_load_event(&class_load_start_event, k, loader_data);
1036 }
1037 }
1038 assert(host_klass != NULL || NULL == cp_patches,
1039 "cp_patches only found with host_klass");
1040
1041 return k;
1042 }
1043
1044 // Add a klass to the system from a stream (called by jni_DefineClass and
1045 // JVM_DefineClass).
1046 // Note: class_name can be NULL. In that case we do not know the name of
1047 // the class until we have parsed the stream.
1048
1049 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1050 Handle class_loader,
1051 Handle protection_domain,
1052 ClassFileStream* st,
1053 TRAPS) {
1054
1055 HandleMark hm(THREAD);
1056
1057 // Classloaders that support parallelism, e.g. bootstrap classloader,
1058 // do not acquire lock here
1059 bool DoObjectLock = true;
1060 if (is_parallelCapable(class_loader)) {
1061 DoObjectLock = false;
1062 }
1063
1064 ClassLoaderData* loader_data = register_loader(class_loader);
1065
1066 // Make sure we are synchronized on the class loader before we proceed
1067 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1068 check_loader_lock_contention(lockObject, THREAD);
1069 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1070
1071 assert(st != NULL, "invariant");
1072
1073 // Parse the stream and create a klass.
1074 // Note that we do this even though this klass might
1075 // already be present in the SystemDictionary, otherwise we would not
1076 // throw potential ClassFormatErrors.
1077 InstanceKlass* k = NULL;
1078
1079 #if INCLUDE_CDS
1080 if (!DumpSharedSpaces) {
1081 k = SystemDictionaryShared::lookup_from_stream(class_name,
1082 class_loader,
1083 protection_domain,
1084 st,
1085 CHECK_NULL);
1086 }
1087 #endif
1088
1089 if (k == NULL) {
1090 if (st->buffer() == NULL) {
1091 return NULL;
1092 }
1093 k = KlassFactory::create_from_stream(st,
1094 class_name,
1095 loader_data,
1096 protection_domain,
1097 NULL, // host_klass
1098 NULL, // cp_patches
1099 CHECK_NULL);
1100 }
1101
1102 assert(k != NULL, "no klass created");
1103 Symbol* h_name = k->name();
1104 assert(class_name == NULL || class_name == h_name, "name mismatch");
1105
1106 // Add class just loaded
1107 // If a class loader supports parallel classloading handle parallel define requests
1108 // find_or_define_instance_class may return a different InstanceKlass
1109 if (is_parallelCapable(class_loader)) {
1110 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1111 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1112 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1113 assert(defined_k != NULL, "Should have a klass if there's no exception");
1114 loader_data->add_to_deallocate_list(k);
1115 k = defined_k;
1116 }
1117 } else {
1118 define_instance_class(k, THREAD);
1119 }
1120
1121 // If defining the class throws an exception register 'k' for cleanup.
1122 if (HAS_PENDING_EXCEPTION) {
1123 assert(k != NULL, "Must have an instance klass here!");
1124 loader_data->add_to_deallocate_list(k);
1125 return NULL;
1126 }
1127
1128 // Make sure we have an entry in the SystemDictionary on success
1129 debug_only( {
1130 MutexLocker mu(SystemDictionary_lock, THREAD);
1131
1132 Klass* check = find_class(h_name, k->class_loader_data());
1133 assert(check == k, "should be present in the dictionary");
1134 } );
1135
1136 return k;
1137 }
1138
1139 #if INCLUDE_CDS
1140 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1141 int number_of_entries) {
1142 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1143 "bad shared dictionary size.");
1144 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1145 _shared_dictionary_size, t, number_of_entries);
1146 }
1147
1148
1149 // If there is a shared dictionary, then find the entry for the
1150 // given shared system class, if any.
1151
1152 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1153 if (shared_dictionary() != NULL) {
1154 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1155 int d_index = shared_dictionary()->hash_to_index(d_hash);
1156
1157 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1158 } else {
1159 return NULL;
1160 }
1161 }
1162
1163
1164 // Load a class from the shared spaces (found through the shared system
1165 // dictionary). Force the superclass and all interfaces to be loaded.
1166 // Update the class definition to include sibling classes and no
1167 // subclasses (yet). [Classes in the shared space are not part of the
1168 // object hierarchy until loaded.]
1169
1170 InstanceKlass* SystemDictionary::load_shared_class(
1171 Symbol* class_name, Handle class_loader, TRAPS) {
1172 InstanceKlass* ik = find_shared_class(class_name);
1173 // Make sure we only return the boot class for the NULL classloader.
1174 if (ik != NULL &&
1175 ik->is_shared_boot_class() && class_loader.is_null()) {
1176 Handle protection_domain;
1177 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1178 }
1179 return NULL;
1180 }
1181
1182 // Check if a shared class can be loaded by the specific classloader:
1183 //
1184 // NULL classloader:
1185 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1186 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1187 // be defined in an unnamed module.
1188 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1189 InstanceKlass* ik,
1190 Handle class_loader, TRAPS) {
1191 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1192 "Cannot use sharing if java.base is patched");
1193 ResourceMark rm;
1194 int path_index = ik->shared_classpath_index();
1195 ClassLoaderData* loader_data = class_loader_data(class_loader);
1196 if (path_index < 0) {
1197 // path_index < 0 indicates that the class is intended for a custom loader
1198 // and should not be loaded by boot/platform/app loaders
1199 if (loader_data->is_builtin_class_loader_data()) {
1200 return false;
1201 } else {
1202 return true;
1203 }
1204 }
1205 SharedClassPathEntry* ent =
1206 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1207 if (!Universe::is_module_initialized()) {
1208 assert(ent != NULL && ent->is_modules_image(),
1209 "Loading non-bootstrap classes before the module system is initialized");
1210 assert(class_loader.is_null(), "sanity");
1211 return true;
1212 }
1213 // Get the pkg_entry from the classloader
1214 TempNewSymbol pkg_name = NULL;
1215 PackageEntry* pkg_entry = NULL;
1216 ModuleEntry* mod_entry = NULL;
1217 const char* pkg_string = NULL;
1218 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1219 if (pkg_name != NULL) {
1220 pkg_string = pkg_name->as_C_string();
1221 if (loader_data != NULL) {
1222 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1223 }
1224 if (pkg_entry != NULL) {
1225 mod_entry = pkg_entry->module();
1226 }
1227 }
1228
1229 // If the archived class is from a module that has been patched at runtime,
1230 // the class cannot be loaded from the archive.
1231 if (mod_entry != NULL && mod_entry->is_patched()) {
1232 return false;
1233 }
1234
1235 if (class_loader.is_null()) {
1236 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1237 // The NULL classloader can load archived class originated from the
1238 // "modules" jimage and the -Xbootclasspath/a. For class from the
1239 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1240 // by the NULL classloader.
1241 if (mod_entry != NULL) {
1242 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1243 // ModuleEntry's location agrees with the archived class' origination.
1244 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1245 return true; // Module class from the "module" jimage
1246 }
1247 }
1248
1249 // If the archived class is not from the "module" jimage, the class can be
1250 // loaded by the NULL classloader if
1251 //
1252 // 1. the class is from the unamed package
1253 // 2. or, the class is not from a module defined in the NULL classloader
1254 // 3. or, the class is from an unamed module
1255 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1256 // the class is from the -Xbootclasspath/a
1257 if (pkg_string == NULL ||
1258 pkg_entry == NULL ||
1259 pkg_entry->in_unnamed_module()) {
1260 assert(mod_entry == NULL ||
1261 mod_entry == loader_data->unnamed_module(),
1262 "the unnamed module is not defined in the classloader");
1263 return true;
1264 }
1265 }
1266 return false;
1267 } else {
1268 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1269 ik, class_loader, pkg_string, pkg_name,
1270 pkg_entry, mod_entry, CHECK_(false));
1271 return res;
1272 }
1273 }
1274
1275 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1276 Handle class_loader,
1277 Handle protection_domain, TRAPS) {
1278
1279 if (ik != NULL) {
1280 Symbol* class_name = ik->name();
1281
1282 bool visible = is_shared_class_visible(
1283 class_name, ik, class_loader, CHECK_NULL);
1284 if (!visible) {
1285 return NULL;
1286 }
1287
1288 // Resolve the superclass and interfaces. They must be the same
1289 // as in dump time, because the layout of <ik> depends on
1290 // the specific layout of ik->super() and ik->local_interfaces().
1291 //
1292 // If unexpected superclass or interfaces are found, we cannot
1293 // load <ik> from the shared archive.
1294
1295 if (ik->super() != NULL) {
1296 Symbol* cn = ik->super()->name();
1297 Klass *s = resolve_super_or_fail(class_name, cn,
1298 class_loader, protection_domain, true, CHECK_NULL);
1299 if (s != ik->super()) {
1300 // The dynamically resolved super class is not the same as the one we used during dump time,
1301 // so we cannot use ik.
1302 return NULL;
1303 } else {
1304 assert(s->is_shared(), "must be");
1305 }
1306 }
1307
1308 Array<Klass*>* interfaces = ik->local_interfaces();
1309 int num_interfaces = interfaces->length();
1310 for (int index = 0; index < num_interfaces; index++) {
1311 Klass* k = interfaces->at(index);
1312 Symbol* name = k->name();
1313 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1314 if (k != i) {
1315 // The dynamically resolved interface class is not the same as the one we used during dump time,
1316 // so we cannot use ik.
1317 return NULL;
1318 } else {
1319 assert(i->is_shared(), "must be");
1320 }
1321 }
1322
1323 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1324 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1325 if (new_ik != NULL) {
1326 // The class is changed by CFLH. Return the new class. The shared class is
1327 // not used.
1328 return new_ik;
1329 }
1330
1331 // Adjust methods to recover missing data. They need addresses for
1332 // interpreter entry points and their default native method address
1333 // must be reset.
1334
1335 // Updating methods must be done under a lock so multiple
1336 // threads don't update these in parallel
1337 //
1338 // Shared classes are all currently loaded by either the bootstrap or
1339 // internal parallel class loaders, so this will never cause a deadlock
1340 // on a custom class loader lock.
1341
1342 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1343 {
1344 HandleMark hm(THREAD);
1345 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1346 check_loader_lock_contention(lockObject, THREAD);
1347 ObjectLocker ol(lockObject, THREAD, true);
1348 // prohibited package check assumes all classes loaded from archive call
1349 // restore_unshareable_info which calls ik->set_package()
1350 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1351 }
1352
1353 ik->print_class_load_logging(loader_data, NULL, NULL);
1354
1355 // For boot loader, ensure that GetSystemPackage knows that a class in this
1356 // package was loaded.
1357 if (class_loader.is_null()) {
1358 int path_index = ik->shared_classpath_index();
1359 ResourceMark rm;
1360 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1361 }
1362
1363 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1364 // Only dump the classes that can be stored into CDS archive
1365 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1366 ResourceMark rm(THREAD);
1367 classlist_file->print_cr("%s", ik->name()->as_C_string());
1368 classlist_file->flush();
1369 }
1370 }
1371
1372 // notify a class loaded from shared object
1373 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1374
1375 ik->set_has_passed_fingerprint_check(false);
1376 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1377 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1378 uint64_t cds_fp = ik->get_stored_fingerprint();
1379 if (aot_fp != 0 && aot_fp == cds_fp) {
1380 // This class matches with a class saved in an AOT library
1381 ik->set_has_passed_fingerprint_check(true);
1382 } else {
1383 ResourceMark rm;
1384 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1385 }
1386 }
1387 }
1388 return ik;
1389 }
1390
1391 void SystemDictionary::clear_invoke_method_table() {
1392 SymbolPropertyEntry* spe = NULL;
1393 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1394 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1395 while (p != NULL) {
1396 spe = p;
1397 p = p->next();
1398 _invoke_method_table->free_entry(spe);
1399 }
1400 }
1401 }
1402 #endif // INCLUDE_CDS
1403
1404 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1405
1406 if (class_loader.is_null()) {
1407 ResourceMark rm;
1408 PackageEntry* pkg_entry = NULL;
1409 bool search_only_bootloader_append = false;
1410 ClassLoaderData *loader_data = class_loader_data(class_loader);
1411
1412 // Find the package in the boot loader's package entry table.
1413 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1414 if (pkg_name != NULL) {
1415 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1416 }
1417
1418 // Prior to attempting to load the class, enforce the boot loader's
1419 // visibility boundaries.
1420 if (!Universe::is_module_initialized()) {
1421 // During bootstrapping, prior to module initialization, any
1422 // class attempting to be loaded must be checked against the
1423 // java.base packages in the boot loader's PackageEntryTable.
1424 // No class outside of java.base is allowed to be loaded during
1425 // this bootstrapping window.
1426 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1427 // Class is either in the unnamed package or in
1428 // a named package within the unnamed module. Either
1429 // case is outside of java.base, do not attempt to
1430 // load the class post java.base definition. If
1431 // java.base has not been defined, let the class load
1432 // and its package will be checked later by
1433 // ModuleEntryTable::verify_javabase_packages.
1434 if (ModuleEntryTable::javabase_defined()) {
1435 return NULL;
1436 }
1437 } else {
1438 // Check that the class' package is defined within java.base.
1439 ModuleEntry* mod_entry = pkg_entry->module();
1440 Symbol* mod_entry_name = mod_entry->name();
1441 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1442 return NULL;
1443 }
1444 }
1445 } else {
1446 // After the module system has been initialized, check if the class'
1447 // package is in a module defined to the boot loader.
1448 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1449 // Class is either in the unnamed package, in a named package
1450 // within a module not defined to the boot loader or in a
1451 // a named package within the unnamed module. In all cases,
1452 // limit visibility to search for the class only in the boot
1453 // loader's append path.
1454 search_only_bootloader_append = true;
1455 }
1456 }
1457
1458 // Prior to bootstrapping's module initialization, never load a class outside
1459 // of the boot loader's module path
1460 assert(Universe::is_module_initialized() ||
1461 !search_only_bootloader_append,
1462 "Attempt to load a class outside of boot loader's module path");
1463
1464 // Search the shared system dictionary for classes preloaded into the
1465 // shared spaces.
1466 InstanceKlass* k = NULL;
1467 {
1468 #if INCLUDE_CDS
1469 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1470 k = load_shared_class(class_name, class_loader, THREAD);
1471 #endif
1472 }
1473
1474 if (k == NULL) {
1475 // Use VM class loader
1476 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1477 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1478 }
1479
1480 // find_or_define_instance_class may return a different InstanceKlass
1481 if (k != NULL) {
1482 InstanceKlass* defined_k =
1483 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1484 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1485 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1486 assert(defined_k != NULL, "Should have a klass if there's no exception");
1487 loader_data->add_to_deallocate_list(k);
1488 k = defined_k;
1489 } else if (HAS_PENDING_EXCEPTION) {
1490 loader_data->add_to_deallocate_list(k);
1491 return NULL;
1492 }
1493 }
1494 return k;
1495 } else {
1496 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1497 ResourceMark rm(THREAD);
1498
1499 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1500 JavaThread* jt = (JavaThread*) THREAD;
1501
1502 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1503 ClassLoader::perf_app_classload_selftime(),
1504 ClassLoader::perf_app_classload_count(),
1505 jt->get_thread_stat()->perf_recursion_counts_addr(),
1506 jt->get_thread_stat()->perf_timers_addr(),
1507 PerfClassTraceTime::CLASS_LOAD);
1508
1509 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1510 // Translate to external class name format, i.e., convert '/' chars to '.'
1511 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1512
1513 JavaValue result(T_OBJECT);
1514
1515 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1516
1517 // Call public unsynchronized loadClass(String) directly for all class loaders.
1518 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1519 // acquire a class-name based lock rather than the class loader object lock.
1520 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1521 JavaCalls::call_virtual(&result,
1522 class_loader,
1523 spec_klass,
1524 vmSymbols::loadClass_name(),
1525 vmSymbols::string_class_signature(),
1526 string,
1527 CHECK_NULL);
1528
1529 assert(result.get_type() == T_OBJECT, "just checking");
1530 oop obj = (oop) result.get_jobject();
1531
1532 // Primitive classes return null since forName() can not be
1533 // used to obtain any of the Class objects representing primitives or void
1534 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1535 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1536 // For user defined Java class loaders, check that the name returned is
1537 // the same as that requested. This check is done for the bootstrap
1538 // loader when parsing the class file.
1539 if (class_name == k->name()) {
1540 return k;
1541 }
1542 }
1543 // Class is not found or has the wrong name, return NULL
1544 return NULL;
1545 }
1546 }
1547
1548 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1549 EventClassDefine event;
1550 if (event.should_commit()) {
1551 event.set_definedClass(k);
1552 event.set_definingClassLoader(def_cld);
1553 event.commit();
1554 }
1555 }
1556
1557 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1558
1559 HandleMark hm(THREAD);
1560 ClassLoaderData* loader_data = k->class_loader_data();
1561 Handle class_loader_h(THREAD, loader_data->class_loader());
1562
1563 // for bootstrap and other parallel classloaders don't acquire lock,
1564 // use placeholder token
1565 // If a parallelCapable class loader calls define_instance_class instead of
1566 // find_or_define_instance_class to get here, we have a timing
1567 // hole with systemDictionary updates and check_constraints
1568 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1569 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1570 compute_loader_lock_object(class_loader_h, THREAD)),
1571 "define called without lock");
1572 }
1573
1574 // Check class-loading constraints. Throw exception if violation is detected.
1575 // Grabs and releases SystemDictionary_lock
1576 // The check_constraints/find_class call and update_dictionary sequence
1577 // must be "atomic" for a specific class/classloader pair so we never
1578 // define two different instanceKlasses for that class/classloader pair.
1579 // Existing classloaders will call define_instance_class with the
1580 // classloader lock held
1581 // Parallel classloaders will call find_or_define_instance_class
1582 // which will require a token to perform the define class
1583 Symbol* name_h = k->name();
1584 Dictionary* dictionary = loader_data->dictionary();
1585 unsigned int d_hash = dictionary->compute_hash(name_h);
1586 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1587
1588 // Register class just loaded with class loader (placed in Vector)
1589 // Note we do this before updating the dictionary, as this can
1590 // fail with an OutOfMemoryError (if it does, we will *not* put this
1591 // class in the dictionary and will not update the class hierarchy).
1592 // JVMTI FollowReferences needs to find the classes this way.
1593 if (k->class_loader() != NULL) {
1594 methodHandle m(THREAD, Universe::loader_addClass_method());
1595 JavaValue result(T_VOID);
1596 JavaCallArguments args(class_loader_h);
1597 args.push_oop(Handle(THREAD, k->java_mirror()));
1598 JavaCalls::call(&result, m, &args, CHECK);
1599 }
1600
1601 // Add the new class. We need recompile lock during update of CHA.
1602 {
1603 unsigned int p_hash = placeholders()->compute_hash(name_h);
1604 int p_index = placeholders()->hash_to_index(p_hash);
1605
1606 MutexLocker mu_r(Compile_lock, THREAD);
1607
1608 // Add to class hierarchy, initialize vtables, and do possible
1609 // deoptimizations.
1610 add_to_hierarchy(k, CHECK); // No exception, but can block
1611
1612 // Add to systemDictionary - so other classes can see it.
1613 // Grabs and releases SystemDictionary_lock
1614 update_dictionary(d_hash, p_index, p_hash,
1615 k, class_loader_h, THREAD);
1616 }
1617 k->eager_initialize(THREAD);
1618
1619 // notify jvmti
1620 if (JvmtiExport::should_post_class_load()) {
1621 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1622 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1623
1624 }
1625 post_class_define_event(k, loader_data);
1626 }
1627
1628 // Support parallel classloading
1629 // All parallel class loaders, including bootstrap classloader
1630 // lock a placeholder entry for this class/class_loader pair
1631 // to allow parallel defines of different classes for this class loader
1632 // With AllowParallelDefine flag==true, in case they do not synchronize around
1633 // FindLoadedClass/DefineClass, calls, we check for parallel
1634 // loading for them, wait if a defineClass is in progress
1635 // and return the initial requestor's results
1636 // This flag does not apply to the bootstrap classloader.
1637 // With AllowParallelDefine flag==false, call through to define_instance_class
1638 // which will throw LinkageError: duplicate class definition.
1639 // False is the requested default.
1640 // For better performance, the class loaders should synchronize
1641 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1642 // potentially waste time reading and parsing the bytestream.
1643 // Note: VM callers should ensure consistency of k/class_name,class_loader
1644 // Be careful when modifying this code: once you have run
1645 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1646 // you need to find_and_remove it before returning.
1647 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1648 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1649 InstanceKlass* k, TRAPS) {
1650
1651 Symbol* name_h = k->name(); // passed in class_name may be null
1652 ClassLoaderData* loader_data = class_loader_data(class_loader);
1653 Dictionary* dictionary = loader_data->dictionary();
1654
1655 unsigned int d_hash = dictionary->compute_hash(name_h);
1656
1657 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1658 unsigned int p_hash = placeholders()->compute_hash(name_h);
1659 int p_index = placeholders()->hash_to_index(p_hash);
1660 PlaceholderEntry* probe;
1661
1662 {
1663 MutexLocker mu(SystemDictionary_lock, THREAD);
1664 // First check if class already defined
1665 if (is_parallelDefine(class_loader)) {
1666 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1667 if (check != NULL) {
1668 return check;
1669 }
1670 }
1671
1672 // Acquire define token for this class/classloader
1673 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1674 // Wait if another thread defining in parallel
1675 // All threads wait - even those that will throw duplicate class: otherwise
1676 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1677 // if other thread has not finished updating dictionary
1678 while (probe->definer() != NULL) {
1679 SystemDictionary_lock->wait();
1680 }
1681 // Only special cases allow parallel defines and can use other thread's results
1682 // Other cases fall through, and may run into duplicate defines
1683 // caught by finding an entry in the SystemDictionary
1684 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1685 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1686 SystemDictionary_lock->notify_all();
1687 #ifdef ASSERT
1688 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1689 assert(check != NULL, "definer missed recording success");
1690 #endif
1691 return probe->instance_klass();
1692 } else {
1693 // This thread will define the class (even if earlier thread tried and had an error)
1694 probe->set_definer(THREAD);
1695 }
1696 }
1697
1698 define_instance_class(k, THREAD);
1699
1700 Handle linkage_exception = Handle(); // null handle
1701
1702 // definer must notify any waiting threads
1703 {
1704 MutexLocker mu(SystemDictionary_lock, THREAD);
1705 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1706 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1707 if (probe != NULL) {
1708 if (HAS_PENDING_EXCEPTION) {
1709 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1710 CLEAR_PENDING_EXCEPTION;
1711 } else {
1712 probe->set_instance_klass(k);
1713 }
1714 probe->set_definer(NULL);
1715 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1716 SystemDictionary_lock->notify_all();
1717 }
1718 }
1719
1720 // Can't throw exception while holding lock due to rank ordering
1721 if (linkage_exception() != NULL) {
1722 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1723 }
1724
1725 return k;
1726 }
1727
1728 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1729 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1730 if (class_loader.is_null()) {
1731 return Handle(THREAD, _system_loader_lock_obj);
1732 } else {
1733 return class_loader;
1734 }
1735 }
1736
1737 // This method is added to check how often we have to wait to grab loader
1738 // lock. The results are being recorded in the performance counters defined in
1739 // ClassLoader::_sync_systemLoaderLockContentionRate and
1740 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1741 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1742 if (!UsePerfData) {
1743 return;
1744 }
1745
1746 assert(!loader_lock.is_null(), "NULL lock object");
1747
1748 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1749 == ObjectSynchronizer::owner_other) {
1750 // contention will likely happen, so increment the corresponding
1751 // contention counter.
1752 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1753 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1754 } else {
1755 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1756 }
1757 }
1758 }
1759
1760 // ----------------------------------------------------------------------------
1761 // Lookup
1762
1763 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1764 Symbol* class_name,
1765 Dictionary* dictionary) {
1766 assert_locked_or_safepoint(SystemDictionary_lock);
1767 int index = dictionary->hash_to_index(hash);
1768 return dictionary->find_class(index, hash, class_name);
1769 }
1770
1771
1772 // Basic find on classes in the midst of being loaded
1773 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1774 ClassLoaderData* loader_data) {
1775 assert_locked_or_safepoint(SystemDictionary_lock);
1776 unsigned int p_hash = placeholders()->compute_hash(class_name);
1777 int p_index = placeholders()->hash_to_index(p_hash);
1778 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1779 }
1780
1781
1782 // Used for assertions and verification only
1783 // Precalculating the hash and index is an optimization because there are many lookups
1784 // before adding the class.
1785 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1786 assert_locked_or_safepoint(SystemDictionary_lock);
1787 #ifndef ASSERT
1788 guarantee(VerifyBeforeGC ||
1789 VerifyDuringGC ||
1790 VerifyBeforeExit ||
1791 VerifyDuringStartup ||
1792 VerifyAfterGC, "too expensive");
1793 #endif
1794
1795 Dictionary* dictionary = loader_data->dictionary();
1796 unsigned int d_hash = dictionary->compute_hash(class_name);
1797 return find_class(d_hash, class_name, dictionary);
1798 }
1799
1800
1801 // ----------------------------------------------------------------------------
1802 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1803 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1804 // before a new class is used.
1805
1806 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1807 assert(k != NULL, "just checking");
1808 assert_locked_or_safepoint(Compile_lock);
1809
1810 // Link into hierachy. Make sure the vtables are initialized before linking into
1811 k->append_to_sibling_list(); // add to superklass/sibling list
1812 k->process_interfaces(THREAD); // handle all "implements" declarations
1813 k->set_init_state(InstanceKlass::loaded);
1814 // Now flush all code that depended on old class hierarchy.
1815 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1816 // Also, first reinitialize vtable because it may have gotten out of synch
1817 // while the new class wasn't connected to the class hierarchy.
1818 CodeCache::flush_dependents_on(k);
1819 }
1820
1821 // ----------------------------------------------------------------------------
1822 // GC support
1823
1824 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1825 // Note: anonymous classes are not in the SD.
1826 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1827 bool do_cleaning) {
1828
1829 bool unloading_occurred;
1830 {
1831 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1832
1833 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1834 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1835 }
1836
1837 if (unloading_occurred) {
1838 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1839 constraints()->purge_loader_constraints();
1840 resolution_errors()->purge_resolution_errors();
1841 }
1842
1843 {
1844 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1845 // Oops referenced by the protection domain cache table may get unreachable independently
1846 // of the class loader (eg. cached protection domain oops). So we need to
1847 // explicitly unlink them here.
1848 _pd_cache_table->unlink();
1849 }
1850
1851 if (do_cleaning) {
1852 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1853 ResolvedMethodTable::unlink();
1854 }
1855
1856 return unloading_occurred;
1857 }
1858
1859 void SystemDictionary::oops_do(OopClosure* f) {
1860 f->do_oop(&_java_system_loader);
1861 f->do_oop(&_java_platform_loader);
1862 f->do_oop(&_system_loader_lock_obj);
1863 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1864
1865 // Visit extra methods
1866 invoke_method_table()->oops_do(f);
1867 }
1868
1869 // CDS: scan and relocate all classes in the system dictionary.
1870 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1871 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1872 }
1873
1874 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1875 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1876 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1877 it->push(well_known_klass_addr((WKID)id));
1878 }
1879 }
1880
1881 void SystemDictionary::methods_do(void f(Method*)) {
1882 // Walk methods in loaded classes
1883 ClassLoaderDataGraph::methods_do(f);
1884 // Walk method handle intrinsics
1885 invoke_method_table()->methods_do(f);
1886 }
1887
1888 class RemoveClassesClosure : public CLDClosure {
1889 public:
1890 void do_cld(ClassLoaderData* cld) {
1891 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1892 cld->dictionary()->remove_classes_in_error_state();
1893 }
1894 }
1895 };
1896
1897 void SystemDictionary::remove_classes_in_error_state() {
1898 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1899 RemoveClassesClosure rcc;
1900 ClassLoaderDataGraph::cld_do(&rcc);
1901 }
1902
1903 // ----------------------------------------------------------------------------
1904 // Initialization
1905
1906 void SystemDictionary::initialize(TRAPS) {
1907 // Allocate arrays
1908 _placeholders = new PlaceholderTable(_placeholder_table_size);
1909 _number_of_modifications = 0;
1910 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1911 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1912 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1913 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1914
1915 // Allocate private object used as system class loader lock
1916 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1917 // Initialize basic classes
1918 initialize_preloaded_classes(CHECK);
1919 }
1920
1921 // Compact table of directions on the initialization of klasses:
1922 static const short wk_init_info[] = {
1923 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1924 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1925 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1926 | (int)SystemDictionary::option ),
1927 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1928 #undef WK_KLASS_INIT_INFO
1929 0
1930 };
1931
1932 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1933 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1934 int info = wk_init_info[id - FIRST_WKID];
1935 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1936 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1937 InstanceKlass** klassp = &_well_known_klasses[id];
1938
1939 bool must_load;
1940 #if INCLUDE_JVMCI
1941 if (EnableJVMCI) {
1942 // If JVMCI is enabled we require its classes to be found.
1943 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1944 } else
1945 #endif
1946 {
1947 must_load = (init_opt < SystemDictionary::Opt);
1948 }
1949
1950 if ((*klassp) == NULL) {
1951 Klass* k;
1952 if (must_load) {
1953 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
1954 } else {
1955 k = resolve_or_null(symbol, CHECK_0); // load optional klass
1956 }
1957 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
1958 }
1959 return ((*klassp) != NULL);
1960 }
1961
1962 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1963 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1964 for (int id = (int)start_id; id < (int)limit_id; id++) {
1965 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1966 int info = wk_init_info[id - FIRST_WKID];
1967 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1968 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1969
1970 initialize_wk_klass((WKID)id, opt, CHECK);
1971 }
1972
1973 // move the starting value forward to the limit:
1974 start_id = limit_id;
1975 }
1976
1977 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1978 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1979
1980 // Create the ModuleEntry for java.base. This call needs to be done here,
1981 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1982 ClassLoader::classLoader_init2(CHECK);
1983
1984 // Preload commonly used klasses
1985 WKID scan = FIRST_WKID;
1986 // first do Object, then String, Class
1987 #if INCLUDE_CDS
1988 if (UseSharedSpaces) {
1989 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1990 // Initialize the constant pool for the Object_class
1991 Object_klass()->constants()->restore_unshareable_info(CHECK);
1992 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1993 } else
1994 #endif
1995 {
1996 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1997 }
1998
1999 // Calculate offsets for String and Class classes since they are loaded and
2000 // can be used after this point.
2001 java_lang_String::compute_offsets();
2002 java_lang_Class::compute_offsets();
2003
2004 // Fixup mirrors for classes loaded before java.lang.Class.
2005 // These calls iterate over the objects currently in the perm gen
2006 // so calling them at this point is matters (not before when there
2007 // are fewer objects and not later after there are more objects
2008 // in the perm gen.
2009 Universe::initialize_basic_type_mirrors(CHECK);
2010 Universe::fixup_mirrors(CHECK);
2011
2012 // do a bunch more:
2013 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2014
2015 // Preload ref klasses and set reference types
2016 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2017 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2018
2019 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2020 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2021 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2022 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2023 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2024
2025 // JSR 292 classes
2026 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2027 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2028 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2029 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2030 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2031
2032 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2033 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2034 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2035 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2036 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2037 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2038 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2039 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2040 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2041 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2042
2043 { // Compute whether we should use checkPackageAccess or NOT
2044 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2045 _has_checkPackageAccess = (method != NULL);
2046 }
2047 }
2048
2049 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2050 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2051 BasicType SystemDictionary::box_klass_type(Klass* k) {
2052 assert(k != NULL, "");
2053 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2054 if (_box_klasses[i] == k)
2055 return (BasicType)i;
2056 }
2057 return T_OBJECT;
2058 }
2059
2060 // Constraints on class loaders. The details of the algorithm can be
2061 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2062 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2063 // that the dictionary needs to maintain a set of contraints that
2064 // must be satisfied by all classes in the dictionary.
2065 // if defining is true, then LinkageError if already in dictionary
2066 // if initiating loader, then ok if InstanceKlass matches existing entry
2067
2068 void SystemDictionary::check_constraints(unsigned int d_hash,
2069 InstanceKlass* k,
2070 Handle class_loader,
2071 bool defining,
2072 TRAPS) {
2073 ResourceMark rm(THREAD);
2074 stringStream ss;
2075 bool throwException = false;
2076
2077 {
2078 Symbol *name = k->name();
2079 ClassLoaderData *loader_data = class_loader_data(class_loader);
2080
2081 MutexLocker mu(SystemDictionary_lock, THREAD);
2082
2083 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2084 if (check != NULL) {
2085 // If different InstanceKlass - duplicate class definition,
2086 // else - ok, class loaded by a different thread in parallel.
2087 // We should only have found it if it was done loading and ok to use.
2088 // The dictionary only holds instance classes, placeholders
2089 // also hold array classes.
2090
2091 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2092 if ((defining == true) || (k != check)) {
2093 throwException = true;
2094 ss.print("loader %s", java_lang_ClassLoader::describe_external(class_loader()));
2095 ss.print(" attempted duplicate %s definition for %s.",
2096 k->external_kind(), k->external_name());
2097 } else {
2098 return;
2099 }
2100 }
2101
2102 #ifdef ASSERT
2103 Symbol* ph_check = find_placeholder(name, loader_data);
2104 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2105 #endif
2106
2107 if (throwException == false) {
2108 if (constraints()->check_or_update(k, class_loader, name) == false) {
2109 throwException = true;
2110 ss.print("loader constraint violation: loader %s",
2111 java_lang_ClassLoader::describe_external(class_loader()));
2112 ss.print(" wants to load %s %s.",
2113 k->external_kind(), k->external_name());
2114 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2115 if (existing_klass->class_loader() != class_loader()) {
2116 ss.print(" A different %s with the same name was previously loaded by %s.",
2117 existing_klass->external_kind(),
2118 java_lang_ClassLoader::describe_external(existing_klass->class_loader()));
2119 }
2120 }
2121 }
2122 }
2123
2124 // Throw error now if needed (cannot throw while holding
2125 // SystemDictionary_lock because of rank ordering)
2126 if (throwException == true) {
2127 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2128 }
2129 }
2130
2131 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2132 // have been called.
2133 void SystemDictionary::update_dictionary(unsigned int d_hash,
2134 int p_index, unsigned int p_hash,
2135 InstanceKlass* k,
2136 Handle class_loader,
2137 TRAPS) {
2138 // Compile_lock prevents systemDictionary updates during compilations
2139 assert_locked_or_safepoint(Compile_lock);
2140 Symbol* name = k->name();
2141 ClassLoaderData *loader_data = class_loader_data(class_loader);
2142
2143 {
2144 MutexLocker mu1(SystemDictionary_lock, THREAD);
2145
2146 // See whether biased locking is enabled and if so set it for this
2147 // klass.
2148 // Note that this must be done past the last potential blocking
2149 // point / safepoint. We enable biased locking lazily using a
2150 // VM_Operation to iterate the SystemDictionary and installing the
2151 // biasable mark word into each InstanceKlass's prototype header.
2152 // To avoid race conditions where we accidentally miss enabling the
2153 // optimization for one class in the process of being added to the
2154 // dictionary, we must not safepoint after the test of
2155 // BiasedLocking::enabled().
2156 if (UseBiasedLocking && BiasedLocking::enabled()) {
2157 // Set biased locking bit for all loaded classes; it will be
2158 // cleared if revocation occurs too often for this type
2159 // NOTE that we must only do this when the class is initally
2160 // defined, not each time it is referenced from a new class loader
2161 if (oopDesc::equals(k->class_loader(), class_loader())) {
2162 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2163 }
2164 }
2165
2166 // Make a new dictionary entry.
2167 Dictionary* dictionary = loader_data->dictionary();
2168 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2169 if (sd_check == NULL) {
2170 dictionary->add_klass(d_hash, name, k);
2171
2172 notice_modification();
2173 }
2174 #ifdef ASSERT
2175 sd_check = find_class(d_hash, name, dictionary);
2176 assert (sd_check != NULL, "should have entry in dictionary");
2177 // Note: there may be a placeholder entry: for circularity testing
2178 // or for parallel defines
2179 #endif
2180 SystemDictionary_lock->notify_all();
2181 }
2182 }
2183
2184
2185 // Try to find a class name using the loader constraints. The
2186 // loader constraints might know about a class that isn't fully loaded
2187 // yet and these will be ignored.
2188 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2189 Symbol* class_name, Handle class_loader, TRAPS) {
2190
2191 // First see if it has been loaded directly.
2192 // Force the protection domain to be null. (This removes protection checks.)
2193 Handle no_protection_domain;
2194 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2195 no_protection_domain, CHECK_NULL);
2196 if (klass != NULL)
2197 return klass;
2198
2199 // Now look to see if it has been loaded elsewhere, and is subject to
2200 // a loader constraint that would require this loader to return the
2201 // klass that is already loaded.
2202 if (FieldType::is_array(class_name)) {
2203 // For array classes, their Klass*s are not kept in the
2204 // constraint table. The element Klass*s are.
2205 FieldArrayInfo fd;
2206 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2207 if (t != T_OBJECT) {
2208 klass = Universe::typeArrayKlassObj(t);
2209 } else {
2210 MutexLocker mu(SystemDictionary_lock, THREAD);
2211 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2212 }
2213 // If element class already loaded, allocate array klass
2214 if (klass != NULL) {
2215 klass = klass->array_klass_or_null(fd.dimension());
2216 }
2217 } else {
2218 MutexLocker mu(SystemDictionary_lock, THREAD);
2219 // Non-array classes are easy: simply check the constraint table.
2220 klass = constraints()->find_constrained_klass(class_name, class_loader);
2221 }
2222
2223 return klass;
2224 }
2225
2226
2227 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2228 Handle class_loader1,
2229 Handle class_loader2,
2230 Thread* THREAD) {
2231 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2232 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2233
2234 Symbol* constraint_name = NULL;
2235 if (!FieldType::is_array(class_name)) {
2236 constraint_name = class_name;
2237 } else {
2238 // For array classes, their Klass*s are not kept in the
2239 // constraint table. The element classes are.
2240 FieldArrayInfo fd;
2241 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2242 // primitive types always pass
2243 if (t != T_OBJECT) {
2244 return true;
2245 } else {
2246 constraint_name = fd.object_key();
2247 }
2248 }
2249
2250 Dictionary* dictionary1 = loader_data1->dictionary();
2251 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2252
2253 Dictionary* dictionary2 = loader_data2->dictionary();
2254 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2255
2256 {
2257 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2258 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2259 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2260 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2261 klass2, class_loader2);
2262 }
2263 }
2264
2265 // Add entry to resolution error table to record the error when the first
2266 // attempt to resolve a reference to a class has failed.
2267 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2268 Symbol* error, Symbol* message) {
2269 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2270 int index = resolution_errors()->hash_to_index(hash);
2271 {
2272 MutexLocker ml(SystemDictionary_lock, Thread::current());
2273 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2274 }
2275 }
2276
2277 // Delete a resolution error for RedefineClasses for a constant pool is going away
2278 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2279 resolution_errors()->delete_entry(pool);
2280 }
2281
2282 // Lookup resolution error table. Returns error if found, otherwise NULL.
2283 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2284 Symbol** message) {
2285 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2286 int index = resolution_errors()->hash_to_index(hash);
2287 {
2288 MutexLocker ml(SystemDictionary_lock, Thread::current());
2289 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2290 if (entry != NULL) {
2291 *message = entry->message();
2292 return entry->error();
2293 } else {
2294 return NULL;
2295 }
2296 }
2297 }
2298
2299
2300 // Signature constraints ensure that callers and callees agree about
2301 // the meaning of type names in their signatures. This routine is the
2302 // intake for constraints. It collects them from several places:
2303 //
2304 // * LinkResolver::resolve_method (if check_access is true) requires
2305 // that the resolving class (the caller) and the defining class of
2306 // the resolved method (the callee) agree on each type in the
2307 // method's signature.
2308 //
2309 // * LinkResolver::resolve_interface_method performs exactly the same
2310 // checks.
2311 //
2312 // * LinkResolver::resolve_field requires that the constant pool
2313 // attempting to link to a field agree with the field's defining
2314 // class about the type of the field signature.
2315 //
2316 // * klassVtable::initialize_vtable requires that, when a class
2317 // overrides a vtable entry allocated by a superclass, that the
2318 // overriding method (i.e., the callee) agree with the superclass
2319 // on each type in the method's signature.
2320 //
2321 // * klassItable::initialize_itable requires that, when a class fills
2322 // in its itables, for each non-abstract method installed in an
2323 // itable, the method (i.e., the callee) agree with the interface
2324 // on each type in the method's signature.
2325 //
2326 // All those methods have a boolean (check_access, checkconstraints)
2327 // which turns off the checks. This is used from specialized contexts
2328 // such as bootstrapping, dumping, and debugging.
2329 //
2330 // No direct constraint is placed between the class and its
2331 // supertypes. Constraints are only placed along linked relations
2332 // between callers and callees. When a method overrides or implements
2333 // an abstract method in a supertype (superclass or interface), the
2334 // constraints are placed as if the supertype were the caller to the
2335 // overriding method. (This works well, since callers to the
2336 // supertype have already established agreement between themselves and
2337 // the supertype.) As a result of all this, a class can disagree with
2338 // its supertype about the meaning of a type name, as long as that
2339 // class neither calls a relevant method of the supertype, nor is
2340 // called (perhaps via an override) from the supertype.
2341 //
2342 //
2343 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2344 //
2345 // Make sure all class components (including arrays) in the given
2346 // signature will be resolved to the same class in both loaders.
2347 // Returns the name of the type that failed a loader constraint check, or
2348 // NULL if no constraint failed. No exception except OOME is thrown.
2349 // Arrays are not added to the loader constraint table, their elements are.
2350 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2351 Handle loader1, Handle loader2,
2352 bool is_method, TRAPS) {
2353 // Nothing to do if loaders are the same.
2354 if (oopDesc::equals(loader1(), loader2())) {
2355 return NULL;
2356 }
2357
2358 SignatureStream sig_strm(signature, is_method);
2359 while (!sig_strm.is_done()) {
2360 if (sig_strm.is_object()) {
2361 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2362 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2363 return sig;
2364 }
2365 }
2366 sig_strm.next();
2367 }
2368 return NULL;
2369 }
2370
2371
2372 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2373 Symbol* signature,
2374 TRAPS) {
2375 methodHandle empty;
2376 assert(MethodHandles::is_signature_polymorphic(iid) &&
2377 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2378 iid != vmIntrinsics::_invokeGeneric,
2379 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2380
2381 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2382 int index = invoke_method_table()->hash_to_index(hash);
2383 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2384 methodHandle m;
2385 if (spe == NULL || spe->method() == NULL) {
2386 spe = NULL;
2387 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2388 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2389 if (!Arguments::is_interpreter_only()) {
2390 // Generate a compiled form of the MH intrinsic.
2391 AdapterHandlerLibrary::create_native_wrapper(m);
2392 // Check if have the compiled code.
2393 if (!m->has_compiled_code()) {
2394 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2395 "Out of space in CodeCache for method handle intrinsic", empty);
2396 }
2397 }
2398 // Now grab the lock. We might have to throw away the new method,
2399 // if a racing thread has managed to install one at the same time.
2400 {
2401 MutexLocker ml(SystemDictionary_lock, THREAD);
2402 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2403 if (spe == NULL)
2404 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2405 if (spe->method() == NULL)
2406 spe->set_method(m());
2407 }
2408 }
2409
2410 assert(spe != NULL && spe->method() != NULL, "");
2411 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2412 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2413 "MH intrinsic invariant");
2414 return spe->method();
2415 }
2416
2417 // Helper for unpacking the return value from linkMethod and linkCallSite.
2418 static methodHandle unpack_method_and_appendix(Handle mname,
2419 Klass* accessing_klass,
2420 objArrayHandle appendix_box,
2421 Handle* appendix_result,
2422 TRAPS) {
2423 methodHandle empty;
2424 if (mname.not_null()) {
2425 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2426 if (m != NULL) {
2427 oop appendix = appendix_box->obj_at(0);
2428 if (TraceMethodHandles) {
2429 #ifndef PRODUCT
2430 ttyLocker ttyl;
2431 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2432 m->print();
2433 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2434 tty->cr();
2435 #endif //PRODUCT
2436 }
2437 (*appendix_result) = Handle(THREAD, appendix);
2438 // the target is stored in the cpCache and if a reference to this
2439 // MemberName is dropped we need a way to make sure the
2440 // class_loader containing this method is kept alive.
2441 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2442 this_key->record_dependency(m->method_holder());
2443 return methodHandle(THREAD, m);
2444 }
2445 }
2446 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2447 return empty;
2448 }
2449
2450 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2451 Symbol* name,
2452 Symbol* signature,
2453 Klass* accessing_klass,
2454 Handle *appendix_result,
2455 Handle *method_type_result,
2456 TRAPS) {
2457 methodHandle empty;
2458 assert(THREAD->can_call_java() ,"");
2459 Handle method_type =
2460 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2461
2462 int ref_kind = JVM_REF_invokeVirtual;
2463 oop name_oop = StringTable::intern(name, CHECK_(empty));
2464 Handle name_str (THREAD, name_oop);
2465 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2466 assert(appendix_box->obj_at(0) == NULL, "");
2467
2468 // This should not happen. JDK code should take care of that.
2469 if (accessing_klass == NULL || method_type.is_null()) {
2470 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2471 }
2472
2473 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2474 JavaCallArguments args;
2475 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2476 args.push_int(ref_kind);
2477 args.push_oop(Handle(THREAD, klass->java_mirror()));
2478 args.push_oop(name_str);
2479 args.push_oop(method_type);
2480 args.push_oop(appendix_box);
2481 JavaValue result(T_OBJECT);
2482 JavaCalls::call_static(&result,
2483 SystemDictionary::MethodHandleNatives_klass(),
2484 vmSymbols::linkMethod_name(),
2485 vmSymbols::linkMethod_signature(),
2486 &args, CHECK_(empty));
2487 Handle mname(THREAD, (oop) result.get_jobject());
2488 (*method_type_result) = method_type;
2489 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2490 }
2491
2492 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2493 // We must ensure that all class loaders everywhere will reach this class, for any client.
2494 // This is a safe bet for public classes in java.lang, such as Object and String.
2495 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2496 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2497 static bool is_always_visible_class(oop mirror) {
2498 Klass* klass = java_lang_Class::as_Klass(mirror);
2499 if (klass->is_objArray_klass()) {
2500 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2501 }
2502 if (klass->is_typeArray_klass()) {
2503 return true; // primitive array
2504 }
2505 assert(klass->is_instance_klass(), "%s", klass->external_name());
2506 return klass->is_public() &&
2507 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2508 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2509 }
2510
2511
2512 // Return the Java mirror (java.lang.Class instance) for a single-character
2513 // descriptor. This result, when available, is the same as produced by the
2514 // heavier API point of the same name that takes a Symbol.
2515 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2516 return java_lang_Class::primitive_mirror(char2type(signature_char));
2517 }
2518
2519 // Find or construct the Java mirror (java.lang.Class instance) for a
2520 // for the given field type signature, as interpreted relative to the
2521 // given class loader. Handles primitives, void, references, arrays,
2522 // and all other reflectable types, except method types.
2523 // N.B. Code in reflection should use this entry point.
2524 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2525 Klass* accessing_klass,
2526 Handle class_loader,
2527 Handle protection_domain,
2528 SignatureStream::FailureMode failure_mode,
2529 TRAPS) {
2530 Handle empty;
2531
2532 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2533 "one or the other, or perhaps neither");
2534
2535 Symbol* type = signature;
2536
2537 // What we have here must be a valid field descriptor,
2538 // and all valid field descriptors are supported.
2539 // Produce the same java.lang.Class that reflection reports.
2540 if (type->utf8_length() == 1) {
2541
2542 // It's a primitive. (Void has a primitive mirror too.)
2543 char ch = (char) type->byte_at(0);
2544 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2545 return Handle(THREAD, find_java_mirror_for_type(ch));
2546
2547 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2548
2549 // It's a reference type.
2550 if (accessing_klass != NULL) {
2551 class_loader = Handle(THREAD, accessing_klass->class_loader());
2552 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2553 }
2554 Klass* constant_type_klass;
2555 if (failure_mode == SignatureStream::ReturnNull) {
2556 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2557 CHECK_(empty));
2558 } else {
2559 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2560 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2561 throw_error, CHECK_(empty));
2562 }
2563 if (constant_type_klass == NULL) {
2564 return Handle(); // report failure this way
2565 }
2566 Handle mirror(THREAD, constant_type_klass->java_mirror());
2567
2568 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2569 if (accessing_klass != NULL) {
2570 Klass* sel_klass = constant_type_klass;
2571 bool fold_type_to_class = true;
2572 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2573 fold_type_to_class, CHECK_(empty));
2574 }
2575
2576 return mirror;
2577
2578 }
2579
2580 // Fall through to an error.
2581 assert(false, "unsupported mirror syntax");
2582 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2583 }
2584
2585
2586 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2587 // signature, as interpreted relative to the given class loader.
2588 // Because of class loader constraints, all method handle usage must be
2589 // consistent with this loader.
2590 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2591 Klass* accessing_klass,
2592 TRAPS) {
2593 Handle empty;
2594 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2595 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2596 int index = invoke_method_table()->hash_to_index(hash);
2597 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2598 if (spe != NULL && spe->method_type() != NULL) {
2599 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2600 return Handle(THREAD, spe->method_type());
2601 } else if (!THREAD->can_call_java()) {
2602 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2603 return Handle(); // do not attempt from within compiler, unless it was cached
2604 }
2605
2606 Handle class_loader, protection_domain;
2607 if (accessing_klass != NULL) {
2608 class_loader = Handle(THREAD, accessing_klass->class_loader());
2609 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2610 }
2611 bool can_be_cached = true;
2612 int npts = ArgumentCount(signature).size();
2613 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2614 int arg = 0;
2615 Handle rt; // the return type from the signature
2616 ResourceMark rm(THREAD);
2617 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2618 oop mirror = NULL;
2619 if (can_be_cached) {
2620 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2621 mirror = ss.as_java_mirror(Handle(), Handle(),
2622 SignatureStream::ReturnNull, CHECK_(empty));
2623 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2624 // Fall back to accessing_klass context.
2625 can_be_cached = false;
2626 }
2627 }
2628 if (!can_be_cached) {
2629 // Resolve, throwing a real error if it doesn't work.
2630 mirror = ss.as_java_mirror(class_loader, protection_domain,
2631 SignatureStream::NCDFError, CHECK_(empty));
2632 }
2633 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2634 if (ss.at_return_type())
2635 rt = Handle(THREAD, mirror);
2636 else
2637 pts->obj_at_put(arg++, mirror);
2638
2639 // Check accessibility.
2640 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2641 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2642 mirror = NULL; // safety
2643 // Emulate ConstantPool::verify_constant_pool_resolve.
2644 bool fold_type_to_class = true;
2645 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2646 fold_type_to_class, CHECK_(empty));
2647 }
2648 }
2649 assert(arg == npts, "");
2650
2651 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2652 JavaCallArguments args(Handle(THREAD, rt()));
2653 args.push_oop(pts);
2654 JavaValue result(T_OBJECT);
2655 JavaCalls::call_static(&result,
2656 SystemDictionary::MethodHandleNatives_klass(),
2657 vmSymbols::findMethodHandleType_name(),
2658 vmSymbols::findMethodHandleType_signature(),
2659 &args, CHECK_(empty));
2660 Handle method_type(THREAD, (oop) result.get_jobject());
2661
2662 if (can_be_cached) {
2663 // We can cache this MethodType inside the JVM.
2664 MutexLocker ml(SystemDictionary_lock, THREAD);
2665 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2666 if (spe == NULL)
2667 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2668 if (spe->method_type() == NULL) {
2669 spe->set_method_type(method_type());
2670 }
2671 }
2672
2673 // report back to the caller with the MethodType
2674 return method_type;
2675 }
2676
2677 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2678 Klass* accessing_klass,
2679 TRAPS) {
2680 Handle empty;
2681 ResourceMark rm(THREAD);
2682 SignatureStream ss(signature, /*is_method=*/ false);
2683 if (!ss.is_done()) {
2684 Handle class_loader, protection_domain;
2685 if (accessing_klass != NULL) {
2686 class_loader = Handle(THREAD, accessing_klass->class_loader());
2687 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2688 }
2689 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2690 ss.next();
2691 if (ss.is_done()) {
2692 return Handle(THREAD, mirror);
2693 }
2694 }
2695 return empty;
2696 }
2697
2698 // Ask Java code to find or construct a method handle constant.
2699 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2700 int ref_kind, //e.g., JVM_REF_invokeVirtual
2701 Klass* callee,
2702 Symbol* name,
2703 Symbol* signature,
2704 TRAPS) {
2705 Handle empty;
2706 if (caller == NULL) {
2707 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2708 }
2709 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2710 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2711
2712 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2713 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2714 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2715 java_lang_invoke_MemberName::set_name (mname(), name_str());
2716 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2717 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2718
2719 if (ref_kind == JVM_REF_invokeVirtual &&
2720 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2721 // Skip resolution for public signature polymorphic methods such as
2722 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2723 // They require appendix argument which MemberName resolution doesn't handle.
2724 // There's special logic on JDK side to handle them
2725 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2726 } else {
2727 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2728 }
2729
2730 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2731 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2732
2733 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2734 JavaCallArguments args;
2735 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2736 args.push_int(ref_kind);
2737 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2738 args.push_oop(name_str);
2739 args.push_oop(type);
2740 JavaValue result(T_OBJECT);
2741 JavaCalls::call_static(&result,
2742 SystemDictionary::MethodHandleNatives_klass(),
2743 vmSymbols::linkMethodHandleConstant_name(),
2744 vmSymbols::linkMethodHandleConstant_signature(),
2745 &args, CHECK_(empty));
2746 return Handle(THREAD, (oop) result.get_jobject());
2747 }
2748
2749 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2750 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2751 int condy_index,
2752 Handle bootstrap_specifier,
2753 Symbol* name,
2754 Symbol* type,
2755 TRAPS) {
2756 Handle empty;
2757 Handle bsm, info;
2758 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2759 bsm = bootstrap_specifier;
2760 } else {
2761 assert(bootstrap_specifier->is_objArray(), "");
2762 objArrayOop args = (objArrayOop) bootstrap_specifier();
2763 assert(args->length() == 2, "");
2764 bsm = Handle(THREAD, args->obj_at(0));
2765 info = Handle(THREAD, args->obj_at(1));
2766 }
2767 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2768 "caller must supply a valid BSM");
2769
2770 // This should not happen. JDK code should take care of that.
2771 if (caller == NULL) {
2772 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2773 }
2774
2775 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2776
2777 // Resolve the constant type in the context of the caller class
2778 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2779 CHECK_(empty));
2780
2781 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2782 JavaCallArguments args;
2783 args.push_oop(Handle(THREAD, caller->java_mirror()));
2784 args.push_int(condy_index);
2785 args.push_oop(bsm);
2786 args.push_oop(constant_name);
2787 args.push_oop(type_mirror);
2788 args.push_oop(info);
2789 JavaValue result(T_OBJECT);
2790 JavaCalls::call_static(&result,
2791 SystemDictionary::MethodHandleNatives_klass(),
2792 vmSymbols::linkDynamicConstant_name(),
2793 vmSymbols::linkDynamicConstant_signature(),
2794 &args, CHECK_(empty));
2795
2796 return Handle(THREAD, (oop) result.get_jobject());
2797 }
2798
2799 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2800 // name and signature, as interpreted relative to the given class loader.
2801 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2802 int indy_index,
2803 Handle bootstrap_specifier,
2804 Symbol* name,
2805 Symbol* type,
2806 Handle *appendix_result,
2807 Handle *method_type_result,
2808 TRAPS) {
2809 methodHandle empty;
2810 Handle bsm, info;
2811 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2812 bsm = bootstrap_specifier;
2813 } else {
2814 objArrayOop args = (objArrayOop) bootstrap_specifier();
2815 assert(args->length() == 2, "");
2816 bsm = Handle(THREAD, args->obj_at(0));
2817 info = Handle(THREAD, args->obj_at(1));
2818 }
2819 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2820 "caller must supply a valid BSM");
2821
2822 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2823 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2824
2825 // This should not happen. JDK code should take care of that.
2826 if (caller == NULL || method_type.is_null()) {
2827 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2828 }
2829
2830 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2831 assert(appendix_box->obj_at(0) == NULL, "");
2832
2833 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2834 JavaCallArguments args;
2835 args.push_oop(Handle(THREAD, caller->java_mirror()));
2836 args.push_int(indy_index);
2837 args.push_oop(bsm);
2838 args.push_oop(method_name);
2839 args.push_oop(method_type);
2840 args.push_oop(info);
2841 args.push_oop(appendix_box);
2842 JavaValue result(T_OBJECT);
2843 JavaCalls::call_static(&result,
2844 SystemDictionary::MethodHandleNatives_klass(),
2845 vmSymbols::linkCallSite_name(),
2846 vmSymbols::linkCallSite_signature(),
2847 &args, CHECK_(empty));
2848 Handle mname(THREAD, (oop) result.get_jobject());
2849 (*method_type_result) = method_type;
2850 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2851 }
2852
2853 // Protection domain cache table handling
2854
2855 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2856 return _pd_cache_table->get(protection_domain);
2857 }
2858
2859 #if INCLUDE_CDS
2860 void SystemDictionary::reorder_dictionary_for_sharing() {
2861 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2862 }
2863 #endif
2864
2865 size_t SystemDictionary::count_bytes_for_buckets() {
2866 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2867 }
2868
2869 size_t SystemDictionary::count_bytes_for_table() {
2870 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2871 }
2872
2873 void SystemDictionary::copy_buckets(char* top, char* end) {
2874 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2875 }
2876
2877 void SystemDictionary::copy_table(char* top, char* end) {
2878 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2879 }
2880
2881 // ----------------------------------------------------------------------------
2882 void SystemDictionary::print_shared(outputStream *st) {
2883 shared_dictionary()->print_on(st);
2884 }
2885
2886 void SystemDictionary::print_on(outputStream *st) {
2887 if (shared_dictionary() != NULL) {
2888 st->print_cr("Shared Dictionary");
2889 shared_dictionary()->print_on(st);
2890 st->cr();
2891 }
2892
2893 GCMutexLocker mu(SystemDictionary_lock);
2894
2895 ClassLoaderDataGraph::print_dictionary(st);
2896
2897 // Placeholders
2898 placeholders()->print_on(st);
2899 st->cr();
2900
2901 // loader constraints - print under SD_lock
2902 constraints()->print_on(st);
2903 st->cr();
2904
2905 _pd_cache_table->print_on(st);
2906 st->cr();
2907 }
2908
2909 void SystemDictionary::verify() {
2910 guarantee(constraints() != NULL,
2911 "Verify of loader constraints failed");
2912 guarantee(placeholders()->number_of_entries() >= 0,
2913 "Verify of placeholders failed");
2914
2915 GCMutexLocker mu(SystemDictionary_lock);
2916
2917 // Verify dictionary
2918 ClassLoaderDataGraph::verify_dictionary();
2919
2920 placeholders()->verify();
2921
2922 // Verify constraint table
2923 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2924 constraints()->verify(placeholders());
2925
2926 _pd_cache_table->verify();
2927 }
2928
2929 void SystemDictionary::dump(outputStream *st, bool verbose) {
2930 assert_locked_or_safepoint(SystemDictionary_lock);
2931 if (verbose) {
2932 print_on(st);
2933 } else {
2934 if (shared_dictionary() != NULL) {
2935 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2936 }
2937 ClassLoaderDataGraph::print_dictionary_statistics(st);
2938 placeholders()->print_table_statistics(st, "Placeholder Table");
2939 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2940 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2941 }
2942 }
2943
2944 // Utility for dumping dictionaries.
2945 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2946 DCmdWithParser(output, heap),
2947 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2948 "BOOLEAN", false, "false") {
2949 _dcmdparser.add_dcmd_option(&_verbose);
2950 }
2951
2952 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2953 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2954 _verbose.value());
2955 VMThread::execute(&dumper);
2956 }
2957
2958 int SystemDictionaryDCmd::num_arguments() {
2959 ResourceMark rm;
2960 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2961 if (dcmd != NULL) {
2962 DCmdMark mark(dcmd);
2963 return dcmd->_dcmdparser.num_arguments();
2964 } else {
2965 return 0;
2966 }
2967 }
2968
2969 class CombineDictionariesClosure : public CLDClosure {
2970 private:
2971 Dictionary* _master_dictionary;
2972 public:
2973 CombineDictionariesClosure(Dictionary* master_dictionary) :
2974 _master_dictionary(master_dictionary) {}
2975 void do_cld(ClassLoaderData* cld) {
2976 ResourceMark rm;
2977 if (cld->is_anonymous()) {
2978 return;
2979 }
2980 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2981 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
2982 Dictionary* curr_dictionary = cld->dictionary();
2983 DictionaryEntry* p = curr_dictionary->bucket(i);
2984 while (p != NULL) {
2985 Symbol* name = p->instance_klass()->name();
2986 unsigned int d_hash = _master_dictionary->compute_hash(name);
2987 int d_index = _master_dictionary->hash_to_index(d_hash);
2988 DictionaryEntry* next = p->next();
2989 if (p->literal()->class_loader_data() != cld) {
2990 // This is an initiating class loader entry; don't use it
2991 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
2992 curr_dictionary->free_entry(p);
2993 } else {
2994 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
2995 curr_dictionary->unlink_entry(p);
2996 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
2997 _master_dictionary->add_entry(d_index, p);
2998 }
2999 p = next;
3000 }
3001 *curr_dictionary->bucket_addr(i) = NULL;
3002 }
3003 }
3004 }
3005 };
3006
3007 // Combining platform and system loader dictionaries into boot loader dictionary.
3008 // During run time, we only have one shared dictionary.
3009 void SystemDictionary::combine_shared_dictionaries() {
3010 assert(DumpSharedSpaces, "dump time only");
3011 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3012 CombineDictionariesClosure cdc(master_dictionary);
3013 ClassLoaderDataGraph::cld_do(&cdc);
3014
3015 // These tables are no longer valid or necessary. Keeping them around will
3016 // cause SystemDictionary::verify() to fail. Let's empty them.
3017 _placeholders = new PlaceholderTable(_placeholder_table_size);
3018 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3019
3020 NOT_PRODUCT(SystemDictionary::verify());
3021 }
3022
3023 void SystemDictionary::initialize_oop_storage() {
3024 _vm_weak_oop_storage =
3025 new OopStorage("VM Weak Oop Handles",
3026 VMWeakAlloc_lock,
3027 VMWeakActive_lock);
3028 }
3029
3030 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3031 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3032 return _vm_weak_oop_storage;
3033 }