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 if (class_loader() != NULL) {
447 ls.print("class loader: ");
448 class_loader()->print_value_on(&ls);
449 } else {
450 ls.print_cr("class loader: NULL");
451 }
452 if (protection_domain() != NULL) {
453 ls.print(" protection domain: ");
454 protection_domain()->print_value_on(&ls);
455 } else {
456 ls.print_cr(" protection domain: NULL");
457 }
458 ls.print(" loading: "); klass->print_value_on(&ls);
459 ls.cr();
460 }
461
462 // This handle and the class_loader handle passed in keeps this class from
463 // being unloaded through several GC points.
464 // The class_loader handle passed in is the initiating loader.
465 Handle mirror(THREAD, klass->java_mirror());
466
467 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
468 JavaCalls::call_special(&result,
469 class_loader,
470 system_loader,
471 vmSymbols::checkPackageAccess_name(),
472 vmSymbols::class_protectiondomain_signature(),
473 mirror,
474 protection_domain,
475 THREAD);
476
477 if (HAS_PENDING_EXCEPTION) {
478 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
479 } else {
480 log_debug(protectiondomain)("granted");
481 }
482
483 if (HAS_PENDING_EXCEPTION) return;
484
485 // If no exception has been thrown, we have validated the protection domain
486 // Insert the protection domain of the initiating class into the set.
487 {
488 ClassLoaderData* loader_data = class_loader_data(class_loader);
489 Dictionary* dictionary = loader_data->dictionary();
490
491 Symbol* kn = klass->name();
492 unsigned int d_hash = dictionary->compute_hash(kn);
493
494 MutexLocker mu(SystemDictionary_lock, THREAD);
495 int d_index = dictionary->hash_to_index(d_hash);
496 dictionary->add_protection_domain(d_index, d_hash, klass,
497 protection_domain, THREAD);
498 }
499 }
500
501 // We only get here if this thread finds that another thread
502 // has already claimed the placeholder token for the current operation,
503 // but that other thread either never owned or gave up the
504 // object lock
505 // Waits on SystemDictionary_lock to indicate placeholder table updated
506 // On return, caller must recheck placeholder table state
507 //
508 // We only get here if
509 // 1) custom classLoader, i.e. not bootstrap classloader
510 // 2) custom classLoader has broken the class loader objectLock
511 // so another thread got here in parallel
512 //
513 // lockObject must be held.
514 // Complicated dance due to lock ordering:
515 // Must first release the classloader object lock to
516 // allow initial definer to complete the class definition
517 // and to avoid deadlock
518 // Reclaim classloader lock object with same original recursion count
519 // Must release SystemDictionary_lock after notify, since
520 // class loader lock must be claimed before SystemDictionary_lock
521 // to prevent deadlocks
522 //
523 // The notify allows applications that did an untimed wait() on
524 // the classloader object lock to not hang.
525 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
526 assert_lock_strong(SystemDictionary_lock);
527
528 bool calledholdinglock
529 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
530 assert(calledholdinglock,"must hold lock for notify");
531 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
532 ObjectSynchronizer::notifyall(lockObject, THREAD);
533 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
534 SystemDictionary_lock->wait();
535 SystemDictionary_lock->unlock();
536 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
537 SystemDictionary_lock->lock();
538 }
539
540 // If the class in is in the placeholder table, class loading is in progress
541 // For cases where the application changes threads to load classes, it
542 // is critical to ClassCircularity detection that we try loading
543 // the superclass on the same thread internally, so we do parallel
544 // super class loading here.
545 // This also is critical in cases where the original thread gets stalled
546 // even in non-circularity situations.
547 // Note: must call resolve_super_or_fail even if null super -
548 // to force placeholder entry creation for this class for circularity detection
549 // Caller must check for pending exception
550 // Returns non-null Klass* if other thread has completed load
551 // and we are done,
552 // If return null Klass* and no pending exception, the caller must load the class
553 InstanceKlass* SystemDictionary::handle_parallel_super_load(
554 Symbol* name, Symbol* superclassname, Handle class_loader,
555 Handle protection_domain, Handle lockObject, TRAPS) {
556
557 ClassLoaderData* loader_data = class_loader_data(class_loader);
558 Dictionary* dictionary = loader_data->dictionary();
559 unsigned int d_hash = dictionary->compute_hash(name);
560 unsigned int p_hash = placeholders()->compute_hash(name);
561 int p_index = placeholders()->hash_to_index(p_hash);
562
563 // superk is not used, resolve_super called for circularity check only
564 // This code is reached in two situations. One if this thread
565 // is loading the same class twice (e.g. ClassCircularity, or
566 // java.lang.instrument).
567 // The second is if another thread started the resolve_super first
568 // and has not yet finished.
569 // In both cases the original caller will clean up the placeholder
570 // entry on error.
571 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
572 superclassname,
573 class_loader,
574 protection_domain,
575 true,
576 CHECK_NULL);
577
578 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
579 // Serial class loaders and bootstrap classloader do wait for superclass loads
580 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
581 MutexLocker mu(SystemDictionary_lock, THREAD);
582 // Check if classloading completed while we were loading superclass or waiting
583 return find_class(d_hash, name, dictionary);
584 }
585
586 // must loop to both handle other placeholder updates
587 // and spurious notifications
588 bool super_load_in_progress = true;
589 PlaceholderEntry* placeholder;
590 while (super_load_in_progress) {
591 MutexLocker mu(SystemDictionary_lock, THREAD);
592 // Check if classloading completed while we were loading superclass or waiting
593 InstanceKlass* check = find_class(d_hash, name, dictionary);
594 if (check != NULL) {
595 // Klass is already loaded, so just return it
596 return check;
597 } else {
598 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
599 if (placeholder && placeholder->super_load_in_progress() ){
600 // We only get here if the application has released the
601 // classloader lock when another thread was in the middle of loading a
602 // superclass/superinterface for this class, and now
603 // this thread is also trying to load this class.
604 // To minimize surprises, the first thread that started to
605 // load a class should be the one to complete the loading
606 // with the classfile it initially expected.
607 // This logic has the current thread wait once it has done
608 // all the superclass/superinterface loading it can, until
609 // the original thread completes the class loading or fails
610 // If it completes we will use the resulting InstanceKlass
611 // which we will find below in the systemDictionary.
612 // We also get here for parallel bootstrap classloader
613 if (class_loader.is_null()) {
614 SystemDictionary_lock->wait();
615 } else {
616 double_lock_wait(lockObject, THREAD);
617 }
618 } else {
619 // If not in SD and not in PH, other thread's load must have failed
620 super_load_in_progress = false;
621 }
622 }
623 }
624 return NULL;
625 }
626
627 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
628 assert(event != NULL, "invariant");
629 assert(k != NULL, "invariant");
630 assert(event->should_commit(), "invariant");
631 event->set_loadedClass(k);
632 event->set_definingClassLoader(k->class_loader_data());
633 event->set_initiatingClassLoader(init_cld);
634 event->commit();
635 }
636
637
638 // Be careful when modifying this code: once you have run
639 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
640 // you need to find_and_remove it before returning.
641 // So be careful to not exit with a CHECK_ macro betweeen these calls.
642 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
643 Handle class_loader,
644 Handle protection_domain,
645 TRAPS) {
646 assert(name != NULL && !FieldType::is_array(name) &&
647 !FieldType::is_obj(name), "invalid class name");
648
649 EventClassLoad class_load_start_event;
650
651 HandleMark hm(THREAD);
652
653 // Fix for 4474172; see evaluation for more details
654 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
655 ClassLoaderData* loader_data = register_loader(class_loader);
656 Dictionary* dictionary = loader_data->dictionary();
657 unsigned int d_hash = dictionary->compute_hash(name);
658
659 // Do lookup to see if class already exist and the protection domain
660 // has the right access
661 // This call uses find which checks protection domain already matches
662 // All subsequent calls use find_class, and set has_loaded_class so that
663 // before we return a result we call out to java to check for valid protection domain
664 // to allow returning the Klass* and add it to the pd_set if it is valid
665 {
666 Klass* probe = dictionary->find(d_hash, name, protection_domain);
667 if (probe != NULL) return probe;
668 }
669
670 // Non-bootstrap class loaders will call out to class loader and
671 // define via jvm/jni_DefineClass which will acquire the
672 // class loader object lock to protect against multiple threads
673 // defining the class in parallel by accident.
674 // This lock must be acquired here so the waiter will find
675 // any successful result in the SystemDictionary and not attempt
676 // the define.
677 // ParallelCapable Classloaders and the bootstrap classloader
678 // do not acquire lock here.
679 bool DoObjectLock = true;
680 if (is_parallelCapable(class_loader)) {
681 DoObjectLock = false;
682 }
683
684 unsigned int p_hash = placeholders()->compute_hash(name);
685 int p_index = placeholders()->hash_to_index(p_hash);
686
687 // Class is not in SystemDictionary so we have to do loading.
688 // Make sure we are synchronized on the class loader before we proceed
689 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
690 check_loader_lock_contention(lockObject, THREAD);
691 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
692
693 // Check again (after locking) if class already exist in SystemDictionary
694 bool class_has_been_loaded = false;
695 bool super_load_in_progress = false;
696 bool havesupername = false;
697 InstanceKlass* k = NULL;
698 PlaceholderEntry* placeholder;
699 Symbol* superclassname = NULL;
700
701 assert(THREAD->can_call_java(),
702 "can not load classes with compiler thread: class=%s, classloader=%s",
703 name->as_C_string(),
704 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
705 {
706 MutexLocker mu(SystemDictionary_lock, THREAD);
707 InstanceKlass* check = find_class(d_hash, name, dictionary);
708 if (check != NULL) {
709 // Klass is already loaded, so just return it
710 class_has_been_loaded = true;
711 k = check;
712 } else {
713 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
714 if (placeholder && placeholder->super_load_in_progress()) {
715 super_load_in_progress = true;
716 if (placeholder->havesupername() == true) {
717 superclassname = placeholder->supername();
718 havesupername = true;
719 }
720 }
721 }
722 }
723
724 // If the class is in the placeholder table, class loading is in progress
725 if (super_load_in_progress && havesupername==true) {
726 k = handle_parallel_super_load(name,
727 superclassname,
728 class_loader,
729 protection_domain,
730 lockObject, THREAD);
731 if (HAS_PENDING_EXCEPTION) {
732 return NULL;
733 }
734 if (k != NULL) {
735 class_has_been_loaded = true;
736 }
737 }
738
739 bool throw_circularity_error = false;
740 if (!class_has_been_loaded) {
741 bool load_instance_added = false;
742
743 // add placeholder entry to record loading instance class
744 // Five cases:
745 // All cases need to prevent modifying bootclasssearchpath
746 // in parallel with a classload of same classname
747 // Redefineclasses uses existence of the placeholder for the duration
748 // of the class load to prevent concurrent redefinition of not completely
749 // defined classes.
750 // case 1. traditional classloaders that rely on the classloader object lock
751 // - no other need for LOAD_INSTANCE
752 // case 2. traditional classloaders that break the classloader object lock
753 // as a deadlock workaround. Detection of this case requires that
754 // this check is done while holding the classloader object lock,
755 // and that lock is still held when calling classloader's loadClass.
756 // For these classloaders, we ensure that the first requestor
757 // completes the load and other requestors wait for completion.
758 // case 3. Bootstrap classloader - don't own objectLocker
759 // This classloader supports parallelism at the classloader level,
760 // but only allows a single load of a class/classloader pair.
761 // No performance benefit and no deadlock issues.
762 // case 4. parallelCapable user level classloaders - without objectLocker
763 // Allow parallel classloading of a class/classloader pair
764
765 {
766 MutexLocker mu(SystemDictionary_lock, THREAD);
767 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
768 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
769 if (oldprobe) {
770 // only need check_seen_thread once, not on each loop
771 // 6341374 java/lang/Instrument with -Xcomp
772 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
773 throw_circularity_error = true;
774 } else {
775 // case 1: traditional: should never see load_in_progress.
776 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
777
778 // case 3: bootstrap classloader: prevent futile classloading,
779 // wait on first requestor
780 if (class_loader.is_null()) {
781 SystemDictionary_lock->wait();
782 } else {
783 // case 2: traditional with broken classloader lock. wait on first
784 // requestor.
785 double_lock_wait(lockObject, THREAD);
786 }
787 // Check if classloading completed while we were waiting
788 InstanceKlass* check = find_class(d_hash, name, dictionary);
789 if (check != NULL) {
790 // Klass is already loaded, so just return it
791 k = check;
792 class_has_been_loaded = true;
793 }
794 // check if other thread failed to load and cleaned up
795 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
796 }
797 }
798 }
799 }
800 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
801 // case 4: parallelCapable: allow competing threads to try
802 // LOAD_INSTANCE in parallel
803
804 if (!throw_circularity_error && !class_has_been_loaded) {
805 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
806 load_instance_added = true;
807 // For class loaders that do not acquire the classloader object lock,
808 // if they did not catch another thread holding LOAD_INSTANCE,
809 // need a check analogous to the acquire ObjectLocker/find_class
810 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
811 // one final check if the load has already completed
812 // class loaders holding the ObjectLock shouldn't find the class here
813 InstanceKlass* check = find_class(d_hash, name, dictionary);
814 if (check != NULL) {
815 // Klass is already loaded, so return it after checking/adding protection domain
816 k = check;
817 class_has_been_loaded = true;
818 }
819 }
820 }
821
822 // must throw error outside of owning lock
823 if (throw_circularity_error) {
824 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
825 ResourceMark rm(THREAD);
826 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
827 }
828
829 if (!class_has_been_loaded) {
830
831 // Do actual loading
832 k = load_instance_class(name, class_loader, THREAD);
833
834 // If everything was OK (no exceptions, no null return value), and
835 // class_loader is NOT the defining loader, do a little more bookkeeping.
836 if (!HAS_PENDING_EXCEPTION && k != NULL &&
837 !oopDesc::equals(k->class_loader(), class_loader())) {
838
839 check_constraints(d_hash, k, class_loader, false, THREAD);
840
841 // Need to check for a PENDING_EXCEPTION again; check_constraints
842 // can throw and doesn't use the CHECK macro.
843 if (!HAS_PENDING_EXCEPTION) {
844 { // Grabbing the Compile_lock prevents systemDictionary updates
845 // during compilations.
846 MutexLocker mu(Compile_lock, THREAD);
847 update_dictionary(d_hash, p_index, p_hash,
848 k, class_loader, THREAD);
849 }
850
851 if (JvmtiExport::should_post_class_load()) {
852 Thread *thread = THREAD;
853 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
854 JvmtiExport::post_class_load((JavaThread *) thread, k);
855 }
856 }
857 }
858 } // load_instance_class
859
860 if (load_instance_added == true) {
861 // clean up placeholder entries for LOAD_INSTANCE success or error
862 // This brackets the SystemDictionary updates for both defining
863 // and initiating loaders
864 MutexLocker mu(SystemDictionary_lock, THREAD);
865 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
866 SystemDictionary_lock->notify_all();
867 }
868 }
869
870 if (HAS_PENDING_EXCEPTION || k == NULL) {
871 return NULL;
872 }
873 if (class_load_start_event.should_commit()) {
874 post_class_load_event(&class_load_start_event, k, loader_data);
875 }
876 #ifdef ASSERT
877 {
878 ClassLoaderData* loader_data = k->class_loader_data();
879 MutexLocker mu(SystemDictionary_lock, THREAD);
880 Klass* kk = find_class(name, loader_data);
881 assert(kk == k, "should be present in dictionary");
882 }
883 #endif
884
885 // return if the protection domain in NULL
886 if (protection_domain() == NULL) return k;
887
888 // Check the protection domain has the right access
889 if (dictionary->is_valid_protection_domain(d_hash, name,
890 protection_domain)) {
891 return k;
892 }
893
894 // Verify protection domain. If it fails an exception is thrown
895 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
896
897 return k;
898 }
899
900
901 // This routine does not lock the system dictionary.
902 //
903 // Since readers don't hold a lock, we must make sure that system
904 // dictionary entries are only removed at a safepoint (when only one
905 // thread is running), and are added to in a safe way (all links must
906 // be updated in an MT-safe manner).
907 //
908 // Callers should be aware that an entry could be added just after
909 // _dictionary->bucket(index) is read here, so the caller will not see
910 // the new entry.
911
912 Klass* SystemDictionary::find(Symbol* class_name,
913 Handle class_loader,
914 Handle protection_domain,
915 TRAPS) {
916
917 // The result of this call should be consistent with the result
918 // of the call to resolve_instance_class_or_null().
919 // See evaluation 6790209 and 4474172 for more details.
920 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
921 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
922
923 if (loader_data == NULL) {
924 // If the ClassLoaderData has not been setup,
925 // then the class loader has no entries in the dictionary.
926 return NULL;
927 }
928
929 Dictionary* dictionary = loader_data->dictionary();
930 unsigned int d_hash = dictionary->compute_hash(class_name);
931 return dictionary->find(d_hash, class_name,
932 protection_domain);
933 }
934
935
936 // Look for a loaded instance or array klass by name. Do not do any loading.
937 // return NULL in case of error.
938 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
939 Handle class_loader,
940 Handle protection_domain,
941 TRAPS) {
942 Klass* k = NULL;
943 assert(class_name != NULL, "class name must be non NULL");
944
945 if (FieldType::is_array(class_name)) {
946 // The name refers to an array. Parse the name.
947 // dimension and object_key in FieldArrayInfo are assigned as a
948 // side-effect of this call
949 FieldArrayInfo fd;
950 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
951 if (t != T_OBJECT) {
952 k = Universe::typeArrayKlassObj(t);
953 } else {
954 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
955 }
956 if (k != NULL) {
957 k = k->array_klass_or_null(fd.dimension());
958 }
959 } else {
960 k = find(class_name, class_loader, protection_domain, THREAD);
961 }
962 return k;
963 }
964
965 // Note: this method is much like resolve_from_stream, but
966 // does not publish the classes via the SystemDictionary.
967 // Handles unsafe_DefineAnonymousClass and redefineclasses
968 // RedefinedClasses do not add to the class hierarchy
969 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
970 Handle class_loader,
971 Handle protection_domain,
972 ClassFileStream* st,
973 const InstanceKlass* host_klass,
974 GrowableArray<Handle>* cp_patches,
975 TRAPS) {
976
977 EventClassLoad class_load_start_event;
978
979 ClassLoaderData* loader_data;
980 if (host_klass != NULL) {
981 // Create a new CLD for anonymous class, that uses the same class loader
982 // as the host_klass
983 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
984 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
985 } else {
986 loader_data = ClassLoaderData::class_loader_data(class_loader());
987 }
988
989 assert(st != NULL, "invariant");
990 assert(st->need_verify(), "invariant");
991
992 // Parse stream and create a klass.
993 // Note that we do this even though this klass might
994 // already be present in the SystemDictionary, otherwise we would not
995 // throw potential ClassFormatErrors.
996
997 InstanceKlass* k = KlassFactory::create_from_stream(st,
998 class_name,
999 loader_data,
1000 protection_domain,
1001 host_klass,
1002 cp_patches,
1003 CHECK_NULL);
1004
1005 if (host_klass != NULL && k != NULL) {
1006 // Anonymous classes must update ClassLoaderData holder (was host_klass loader)
1007 // so that they can be unloaded when the mirror is no longer referenced.
1008 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1009
1010 {
1011 MutexLocker mu_r(Compile_lock, THREAD);
1012
1013 // Add to class hierarchy, initialize vtables, and do possible
1014 // deoptimizations.
1015 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1016
1017 // But, do not add to dictionary.
1018
1019 // compiled code dependencies need to be validated anyway
1020 notice_modification();
1021 }
1022
1023 // Rewrite and patch constant pool here.
1024 k->link_class(CHECK_NULL);
1025 if (cp_patches != NULL) {
1026 k->constants()->patch_resolved_references(cp_patches);
1027 }
1028
1029 // If it's anonymous, initialize it now, since nobody else will.
1030 k->eager_initialize(CHECK_NULL);
1031
1032 // notify jvmti
1033 if (JvmtiExport::should_post_class_load()) {
1034 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1035 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1036 }
1037 if (class_load_start_event.should_commit()) {
1038 post_class_load_event(&class_load_start_event, k, loader_data);
1039 }
1040 }
1041 assert(host_klass != NULL || NULL == cp_patches,
1042 "cp_patches only found with host_klass");
1043
1044 return k;
1045 }
1046
1047 // Add a klass to the system from a stream (called by jni_DefineClass and
1048 // JVM_DefineClass).
1049 // Note: class_name can be NULL. In that case we do not know the name of
1050 // the class until we have parsed the stream.
1051
1052 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1053 Handle class_loader,
1054 Handle protection_domain,
1055 ClassFileStream* st,
1056 TRAPS) {
1057
1058 HandleMark hm(THREAD);
1059
1060 // Classloaders that support parallelism, e.g. bootstrap classloader,
1061 // do not acquire lock here
1062 bool DoObjectLock = true;
1063 if (is_parallelCapable(class_loader)) {
1064 DoObjectLock = false;
1065 }
1066
1067 ClassLoaderData* loader_data = register_loader(class_loader);
1068
1069 // Make sure we are synchronized on the class loader before we proceed
1070 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1071 check_loader_lock_contention(lockObject, THREAD);
1072 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1073
1074 assert(st != NULL, "invariant");
1075
1076 // Parse the stream and create a klass.
1077 // Note that we do this even though this klass might
1078 // already be present in the SystemDictionary, otherwise we would not
1079 // throw potential ClassFormatErrors.
1080 InstanceKlass* k = NULL;
1081
1082 #if INCLUDE_CDS
1083 if (!DumpSharedSpaces) {
1084 k = SystemDictionaryShared::lookup_from_stream(class_name,
1085 class_loader,
1086 protection_domain,
1087 st,
1088 CHECK_NULL);
1089 }
1090 #endif
1091
1092 if (k == NULL) {
1093 if (st->buffer() == NULL) {
1094 return NULL;
1095 }
1096 k = KlassFactory::create_from_stream(st,
1097 class_name,
1098 loader_data,
1099 protection_domain,
1100 NULL, // host_klass
1101 NULL, // cp_patches
1102 CHECK_NULL);
1103 }
1104
1105 assert(k != NULL, "no klass created");
1106 Symbol* h_name = k->name();
1107 assert(class_name == NULL || class_name == h_name, "name mismatch");
1108
1109 // Add class just loaded
1110 // If a class loader supports parallel classloading handle parallel define requests
1111 // find_or_define_instance_class may return a different InstanceKlass
1112 if (is_parallelCapable(class_loader)) {
1113 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1114 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1115 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1116 assert(defined_k != NULL, "Should have a klass if there's no exception");
1117 loader_data->add_to_deallocate_list(k);
1118 k = defined_k;
1119 }
1120 } else {
1121 define_instance_class(k, THREAD);
1122 }
1123
1124 // If defining the class throws an exception register 'k' for cleanup.
1125 if (HAS_PENDING_EXCEPTION) {
1126 assert(k != NULL, "Must have an instance klass here!");
1127 loader_data->add_to_deallocate_list(k);
1128 return NULL;
1129 }
1130
1131 // Make sure we have an entry in the SystemDictionary on success
1132 debug_only( {
1133 MutexLocker mu(SystemDictionary_lock, THREAD);
1134
1135 Klass* check = find_class(h_name, k->class_loader_data());
1136 assert(check == k, "should be present in the dictionary");
1137 } );
1138
1139 return k;
1140 }
1141
1142 #if INCLUDE_CDS
1143 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1144 int number_of_entries) {
1145 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1146 "bad shared dictionary size.");
1147 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1148 _shared_dictionary_size, t, number_of_entries);
1149 }
1150
1151
1152 // If there is a shared dictionary, then find the entry for the
1153 // given shared system class, if any.
1154
1155 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1156 if (shared_dictionary() != NULL) {
1157 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1158 int d_index = shared_dictionary()->hash_to_index(d_hash);
1159
1160 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1161 } else {
1162 return NULL;
1163 }
1164 }
1165
1166
1167 // Load a class from the shared spaces (found through the shared system
1168 // dictionary). Force the superclass and all interfaces to be loaded.
1169 // Update the class definition to include sibling classes and no
1170 // subclasses (yet). [Classes in the shared space are not part of the
1171 // object hierarchy until loaded.]
1172
1173 InstanceKlass* SystemDictionary::load_shared_class(
1174 Symbol* class_name, Handle class_loader, TRAPS) {
1175 InstanceKlass* ik = find_shared_class(class_name);
1176 // Make sure we only return the boot class for the NULL classloader.
1177 if (ik != NULL &&
1178 ik->is_shared_boot_class() && class_loader.is_null()) {
1179 Handle protection_domain;
1180 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1181 }
1182 return NULL;
1183 }
1184
1185 // Check if a shared class can be loaded by the specific classloader:
1186 //
1187 // NULL classloader:
1188 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1189 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1190 // be defined in an unnamed module.
1191 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1192 InstanceKlass* ik,
1193 Handle class_loader, TRAPS) {
1194 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1195 "Cannot use sharing if java.base is patched");
1196 ResourceMark rm;
1197 int path_index = ik->shared_classpath_index();
1198 ClassLoaderData* loader_data = class_loader_data(class_loader);
1199 if (path_index < 0) {
1200 // path_index < 0 indicates that the class is intended for a custom loader
1201 // and should not be loaded by boot/platform/app loaders
1202 if (loader_data->is_builtin_class_loader_data()) {
1203 return false;
1204 } else {
1205 return true;
1206 }
1207 }
1208 SharedClassPathEntry* ent =
1209 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1210 if (!Universe::is_module_initialized()) {
1211 assert(ent != NULL && ent->is_modules_image(),
1212 "Loading non-bootstrap classes before the module system is initialized");
1213 assert(class_loader.is_null(), "sanity");
1214 return true;
1215 }
1216 // Get the pkg_entry from the classloader
1217 TempNewSymbol pkg_name = NULL;
1218 PackageEntry* pkg_entry = NULL;
1219 ModuleEntry* mod_entry = NULL;
1220 const char* pkg_string = NULL;
1221 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1222 if (pkg_name != NULL) {
1223 pkg_string = pkg_name->as_C_string();
1224 if (loader_data != NULL) {
1225 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1226 }
1227 if (pkg_entry != NULL) {
1228 mod_entry = pkg_entry->module();
1229 }
1230 }
1231
1232 // If the archived class is from a module that has been patched at runtime,
1233 // the class cannot be loaded from the archive.
1234 if (mod_entry != NULL && mod_entry->is_patched()) {
1235 return false;
1236 }
1237
1238 if (class_loader.is_null()) {
1239 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1240 // The NULL classloader can load archived class originated from the
1241 // "modules" jimage and the -Xbootclasspath/a. For class from the
1242 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1243 // by the NULL classloader.
1244 if (mod_entry != NULL) {
1245 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1246 // ModuleEntry's location agrees with the archived class' origination.
1247 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1248 return true; // Module class from the "module" jimage
1249 }
1250 }
1251
1252 // If the archived class is not from the "module" jimage, the class can be
1253 // loaded by the NULL classloader if
1254 //
1255 // 1. the class is from the unamed package
1256 // 2. or, the class is not from a module defined in the NULL classloader
1257 // 3. or, the class is from an unamed module
1258 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1259 // the class is from the -Xbootclasspath/a
1260 if (pkg_string == NULL ||
1261 pkg_entry == NULL ||
1262 pkg_entry->in_unnamed_module()) {
1263 assert(mod_entry == NULL ||
1264 mod_entry == loader_data->unnamed_module(),
1265 "the unnamed module is not defined in the classloader");
1266 return true;
1267 }
1268 }
1269 return false;
1270 } else {
1271 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1272 ik, class_loader, pkg_string, pkg_name,
1273 pkg_entry, mod_entry, CHECK_(false));
1274 return res;
1275 }
1276 }
1277
1278 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1279 Handle class_loader,
1280 Handle protection_domain, TRAPS) {
1281
1282 if (ik != NULL) {
1283 Symbol* class_name = ik->name();
1284
1285 bool visible = is_shared_class_visible(
1286 class_name, ik, class_loader, CHECK_NULL);
1287 if (!visible) {
1288 return NULL;
1289 }
1290
1291 // Resolve the superclass and interfaces. They must be the same
1292 // as in dump time, because the layout of <ik> depends on
1293 // the specific layout of ik->super() and ik->local_interfaces().
1294 //
1295 // If unexpected superclass or interfaces are found, we cannot
1296 // load <ik> from the shared archive.
1297
1298 if (ik->super() != NULL) {
1299 Symbol* cn = ik->super()->name();
1300 Klass *s = resolve_super_or_fail(class_name, cn,
1301 class_loader, protection_domain, true, CHECK_NULL);
1302 if (s != ik->super()) {
1303 // The dynamically resolved super class is not the same as the one we used during dump time,
1304 // so we cannot use ik.
1305 return NULL;
1306 } else {
1307 assert(s->is_shared(), "must be");
1308 }
1309 }
1310
1311 Array<Klass*>* interfaces = ik->local_interfaces();
1312 int num_interfaces = interfaces->length();
1313 for (int index = 0; index < num_interfaces; index++) {
1314 Klass* k = interfaces->at(index);
1315 Symbol* name = k->name();
1316 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1317 if (k != i) {
1318 // The dynamically resolved interface class is not the same as the one we used during dump time,
1319 // so we cannot use ik.
1320 return NULL;
1321 } else {
1322 assert(i->is_shared(), "must be");
1323 }
1324 }
1325
1326 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1327 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1328 if (new_ik != NULL) {
1329 // The class is changed by CFLH. Return the new class. The shared class is
1330 // not used.
1331 return new_ik;
1332 }
1333
1334 // Adjust methods to recover missing data. They need addresses for
1335 // interpreter entry points and their default native method address
1336 // must be reset.
1337
1338 // Updating methods must be done under a lock so multiple
1339 // threads don't update these in parallel
1340 //
1341 // Shared classes are all currently loaded by either the bootstrap or
1342 // internal parallel class loaders, so this will never cause a deadlock
1343 // on a custom class loader lock.
1344
1345 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1346 {
1347 HandleMark hm(THREAD);
1348 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1349 check_loader_lock_contention(lockObject, THREAD);
1350 ObjectLocker ol(lockObject, THREAD, true);
1351 // prohibited package check assumes all classes loaded from archive call
1352 // restore_unshareable_info which calls ik->set_package()
1353 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1354 }
1355
1356 ik->print_class_load_logging(loader_data, NULL, NULL);
1357
1358 // For boot loader, ensure that GetSystemPackage knows that a class in this
1359 // package was loaded.
1360 if (class_loader.is_null()) {
1361 int path_index = ik->shared_classpath_index();
1362 ResourceMark rm;
1363 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1364 }
1365
1366 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1367 // Only dump the classes that can be stored into CDS archive
1368 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1369 ResourceMark rm(THREAD);
1370 classlist_file->print_cr("%s", ik->name()->as_C_string());
1371 classlist_file->flush();
1372 }
1373 }
1374
1375 // notify a class loaded from shared object
1376 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1377
1378 ik->set_has_passed_fingerprint_check(false);
1379 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1380 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1381 uint64_t cds_fp = ik->get_stored_fingerprint();
1382 if (aot_fp != 0 && aot_fp == cds_fp) {
1383 // This class matches with a class saved in an AOT library
1384 ik->set_has_passed_fingerprint_check(true);
1385 } else {
1386 ResourceMark rm;
1387 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1388 }
1389 }
1390 }
1391 return ik;
1392 }
1393
1394 void SystemDictionary::clear_invoke_method_table() {
1395 SymbolPropertyEntry* spe = NULL;
1396 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1397 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1398 while (p != NULL) {
1399 spe = p;
1400 p = p->next();
1401 _invoke_method_table->free_entry(spe);
1402 }
1403 }
1404 }
1405 #endif // INCLUDE_CDS
1406
1407 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1408
1409 if (class_loader.is_null()) {
1410 ResourceMark rm;
1411 PackageEntry* pkg_entry = NULL;
1412 bool search_only_bootloader_append = false;
1413 ClassLoaderData *loader_data = class_loader_data(class_loader);
1414
1415 // Find the package in the boot loader's package entry table.
1416 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1417 if (pkg_name != NULL) {
1418 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1419 }
1420
1421 // Prior to attempting to load the class, enforce the boot loader's
1422 // visibility boundaries.
1423 if (!Universe::is_module_initialized()) {
1424 // During bootstrapping, prior to module initialization, any
1425 // class attempting to be loaded must be checked against the
1426 // java.base packages in the boot loader's PackageEntryTable.
1427 // No class outside of java.base is allowed to be loaded during
1428 // this bootstrapping window.
1429 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1430 // Class is either in the unnamed package or in
1431 // a named package within the unnamed module. Either
1432 // case is outside of java.base, do not attempt to
1433 // load the class post java.base definition. If
1434 // java.base has not been defined, let the class load
1435 // and its package will be checked later by
1436 // ModuleEntryTable::verify_javabase_packages.
1437 if (ModuleEntryTable::javabase_defined()) {
1438 return NULL;
1439 }
1440 } else {
1441 // Check that the class' package is defined within java.base.
1442 ModuleEntry* mod_entry = pkg_entry->module();
1443 Symbol* mod_entry_name = mod_entry->name();
1444 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1445 return NULL;
1446 }
1447 }
1448 } else {
1449 // After the module system has been initialized, check if the class'
1450 // package is in a module defined to the boot loader.
1451 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1452 // Class is either in the unnamed package, in a named package
1453 // within a module not defined to the boot loader or in a
1454 // a named package within the unnamed module. In all cases,
1455 // limit visibility to search for the class only in the boot
1456 // loader's append path.
1457 search_only_bootloader_append = true;
1458 }
1459 }
1460
1461 // Prior to bootstrapping's module initialization, never load a class outside
1462 // of the boot loader's module path
1463 assert(Universe::is_module_initialized() ||
1464 !search_only_bootloader_append,
1465 "Attempt to load a class outside of boot loader's module path");
1466
1467 // Search the shared system dictionary for classes preloaded into the
1468 // shared spaces.
1469 InstanceKlass* k = NULL;
1470 {
1471 #if INCLUDE_CDS
1472 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1473 k = load_shared_class(class_name, class_loader, THREAD);
1474 #endif
1475 }
1476
1477 if (k == NULL) {
1478 // Use VM class loader
1479 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1480 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1481 }
1482
1483 // find_or_define_instance_class may return a different InstanceKlass
1484 if (k != NULL) {
1485 InstanceKlass* defined_k =
1486 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1487 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1488 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1489 assert(defined_k != NULL, "Should have a klass if there's no exception");
1490 loader_data->add_to_deallocate_list(k);
1491 k = defined_k;
1492 } else if (HAS_PENDING_EXCEPTION) {
1493 loader_data->add_to_deallocate_list(k);
1494 return NULL;
1495 }
1496 }
1497 return k;
1498 } else {
1499 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1500 ResourceMark rm(THREAD);
1501
1502 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1503 JavaThread* jt = (JavaThread*) THREAD;
1504
1505 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1506 ClassLoader::perf_app_classload_selftime(),
1507 ClassLoader::perf_app_classload_count(),
1508 jt->get_thread_stat()->perf_recursion_counts_addr(),
1509 jt->get_thread_stat()->perf_timers_addr(),
1510 PerfClassTraceTime::CLASS_LOAD);
1511
1512 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1513 // Translate to external class name format, i.e., convert '/' chars to '.'
1514 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1515
1516 JavaValue result(T_OBJECT);
1517
1518 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1519
1520 // Call public unsynchronized loadClass(String) directly for all class loaders.
1521 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1522 // acquire a class-name based lock rather than the class loader object lock.
1523 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1524 JavaCalls::call_virtual(&result,
1525 class_loader,
1526 spec_klass,
1527 vmSymbols::loadClass_name(),
1528 vmSymbols::string_class_signature(),
1529 string,
1530 CHECK_NULL);
1531
1532 assert(result.get_type() == T_OBJECT, "just checking");
1533 oop obj = (oop) result.get_jobject();
1534
1535 // Primitive classes return null since forName() can not be
1536 // used to obtain any of the Class objects representing primitives or void
1537 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1538 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1539 // For user defined Java class loaders, check that the name returned is
1540 // the same as that requested. This check is done for the bootstrap
1541 // loader when parsing the class file.
1542 if (class_name == k->name()) {
1543 return k;
1544 }
1545 }
1546 // Class is not found or has the wrong name, return NULL
1547 return NULL;
1548 }
1549 }
1550
1551 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1552 EventClassDefine event;
1553 if (event.should_commit()) {
1554 event.set_definedClass(k);
1555 event.set_definingClassLoader(def_cld);
1556 event.commit();
1557 }
1558 }
1559
1560 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1561
1562 HandleMark hm(THREAD);
1563 ClassLoaderData* loader_data = k->class_loader_data();
1564 Handle class_loader_h(THREAD, loader_data->class_loader());
1565
1566 // for bootstrap and other parallel classloaders don't acquire lock,
1567 // use placeholder token
1568 // If a parallelCapable class loader calls define_instance_class instead of
1569 // find_or_define_instance_class to get here, we have a timing
1570 // hole with systemDictionary updates and check_constraints
1571 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1572 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1573 compute_loader_lock_object(class_loader_h, THREAD)),
1574 "define called without lock");
1575 }
1576
1577 // Check class-loading constraints. Throw exception if violation is detected.
1578 // Grabs and releases SystemDictionary_lock
1579 // The check_constraints/find_class call and update_dictionary sequence
1580 // must be "atomic" for a specific class/classloader pair so we never
1581 // define two different instanceKlasses for that class/classloader pair.
1582 // Existing classloaders will call define_instance_class with the
1583 // classloader lock held
1584 // Parallel classloaders will call find_or_define_instance_class
1585 // which will require a token to perform the define class
1586 Symbol* name_h = k->name();
1587 Dictionary* dictionary = loader_data->dictionary();
1588 unsigned int d_hash = dictionary->compute_hash(name_h);
1589 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1590
1591 // Register class just loaded with class loader (placed in Vector)
1592 // Note we do this before updating the dictionary, as this can
1593 // fail with an OutOfMemoryError (if it does, we will *not* put this
1594 // class in the dictionary and will not update the class hierarchy).
1595 // JVMTI FollowReferences needs to find the classes this way.
1596 if (k->class_loader() != NULL) {
1597 methodHandle m(THREAD, Universe::loader_addClass_method());
1598 JavaValue result(T_VOID);
1599 JavaCallArguments args(class_loader_h);
1600 args.push_oop(Handle(THREAD, k->java_mirror()));
1601 JavaCalls::call(&result, m, &args, CHECK);
1602 }
1603
1604 // Add the new class. We need recompile lock during update of CHA.
1605 {
1606 unsigned int p_hash = placeholders()->compute_hash(name_h);
1607 int p_index = placeholders()->hash_to_index(p_hash);
1608
1609 MutexLocker mu_r(Compile_lock, THREAD);
1610
1611 // Add to class hierarchy, initialize vtables, and do possible
1612 // deoptimizations.
1613 add_to_hierarchy(k, CHECK); // No exception, but can block
1614
1615 // Add to systemDictionary - so other classes can see it.
1616 // Grabs and releases SystemDictionary_lock
1617 update_dictionary(d_hash, p_index, p_hash,
1618 k, class_loader_h, THREAD);
1619 }
1620 k->eager_initialize(THREAD);
1621
1622 // notify jvmti
1623 if (JvmtiExport::should_post_class_load()) {
1624 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1625 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1626
1627 }
1628 post_class_define_event(k, loader_data);
1629 }
1630
1631 // Support parallel classloading
1632 // All parallel class loaders, including bootstrap classloader
1633 // lock a placeholder entry for this class/class_loader pair
1634 // to allow parallel defines of different classes for this class loader
1635 // With AllowParallelDefine flag==true, in case they do not synchronize around
1636 // FindLoadedClass/DefineClass, calls, we check for parallel
1637 // loading for them, wait if a defineClass is in progress
1638 // and return the initial requestor's results
1639 // This flag does not apply to the bootstrap classloader.
1640 // With AllowParallelDefine flag==false, call through to define_instance_class
1641 // which will throw LinkageError: duplicate class definition.
1642 // False is the requested default.
1643 // For better performance, the class loaders should synchronize
1644 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1645 // potentially waste time reading and parsing the bytestream.
1646 // Note: VM callers should ensure consistency of k/class_name,class_loader
1647 // Be careful when modifying this code: once you have run
1648 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1649 // you need to find_and_remove it before returning.
1650 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1651 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1652 InstanceKlass* k, TRAPS) {
1653
1654 Symbol* name_h = k->name(); // passed in class_name may be null
1655 ClassLoaderData* loader_data = class_loader_data(class_loader);
1656 Dictionary* dictionary = loader_data->dictionary();
1657
1658 unsigned int d_hash = dictionary->compute_hash(name_h);
1659
1660 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1661 unsigned int p_hash = placeholders()->compute_hash(name_h);
1662 int p_index = placeholders()->hash_to_index(p_hash);
1663 PlaceholderEntry* probe;
1664
1665 {
1666 MutexLocker mu(SystemDictionary_lock, THREAD);
1667 // First check if class already defined
1668 if (is_parallelDefine(class_loader)) {
1669 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1670 if (check != NULL) {
1671 return check;
1672 }
1673 }
1674
1675 // Acquire define token for this class/classloader
1676 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1677 // Wait if another thread defining in parallel
1678 // All threads wait - even those that will throw duplicate class: otherwise
1679 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1680 // if other thread has not finished updating dictionary
1681 while (probe->definer() != NULL) {
1682 SystemDictionary_lock->wait();
1683 }
1684 // Only special cases allow parallel defines and can use other thread's results
1685 // Other cases fall through, and may run into duplicate defines
1686 // caught by finding an entry in the SystemDictionary
1687 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1688 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1689 SystemDictionary_lock->notify_all();
1690 #ifdef ASSERT
1691 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1692 assert(check != NULL, "definer missed recording success");
1693 #endif
1694 return probe->instance_klass();
1695 } else {
1696 // This thread will define the class (even if earlier thread tried and had an error)
1697 probe->set_definer(THREAD);
1698 }
1699 }
1700
1701 define_instance_class(k, THREAD);
1702
1703 Handle linkage_exception = Handle(); // null handle
1704
1705 // definer must notify any waiting threads
1706 {
1707 MutexLocker mu(SystemDictionary_lock, THREAD);
1708 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1709 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1710 if (probe != NULL) {
1711 if (HAS_PENDING_EXCEPTION) {
1712 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1713 CLEAR_PENDING_EXCEPTION;
1714 } else {
1715 probe->set_instance_klass(k);
1716 }
1717 probe->set_definer(NULL);
1718 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1719 SystemDictionary_lock->notify_all();
1720 }
1721 }
1722
1723 // Can't throw exception while holding lock due to rank ordering
1724 if (linkage_exception() != NULL) {
1725 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1726 }
1727
1728 return k;
1729 }
1730
1731 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1732 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1733 if (class_loader.is_null()) {
1734 return Handle(THREAD, _system_loader_lock_obj);
1735 } else {
1736 return class_loader;
1737 }
1738 }
1739
1740 // This method is added to check how often we have to wait to grab loader
1741 // lock. The results are being recorded in the performance counters defined in
1742 // ClassLoader::_sync_systemLoaderLockContentionRate and
1743 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1744 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1745 if (!UsePerfData) {
1746 return;
1747 }
1748
1749 assert(!loader_lock.is_null(), "NULL lock object");
1750
1751 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1752 == ObjectSynchronizer::owner_other) {
1753 // contention will likely happen, so increment the corresponding
1754 // contention counter.
1755 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1756 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1757 } else {
1758 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1759 }
1760 }
1761 }
1762
1763 // ----------------------------------------------------------------------------
1764 // Lookup
1765
1766 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1767 Symbol* class_name,
1768 Dictionary* dictionary) {
1769 assert_locked_or_safepoint(SystemDictionary_lock);
1770 int index = dictionary->hash_to_index(hash);
1771 return dictionary->find_class(index, hash, class_name);
1772 }
1773
1774
1775 // Basic find on classes in the midst of being loaded
1776 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1777 ClassLoaderData* loader_data) {
1778 assert_locked_or_safepoint(SystemDictionary_lock);
1779 unsigned int p_hash = placeholders()->compute_hash(class_name);
1780 int p_index = placeholders()->hash_to_index(p_hash);
1781 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1782 }
1783
1784
1785 // Used for assertions and verification only
1786 // Precalculating the hash and index is an optimization because there are many lookups
1787 // before adding the class.
1788 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1789 assert_locked_or_safepoint(SystemDictionary_lock);
1790 #ifndef ASSERT
1791 guarantee(VerifyBeforeGC ||
1792 VerifyDuringGC ||
1793 VerifyBeforeExit ||
1794 VerifyDuringStartup ||
1795 VerifyAfterGC, "too expensive");
1796 #endif
1797
1798 Dictionary* dictionary = loader_data->dictionary();
1799 unsigned int d_hash = dictionary->compute_hash(class_name);
1800 return find_class(d_hash, class_name, dictionary);
1801 }
1802
1803
1804 // ----------------------------------------------------------------------------
1805 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1806 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1807 // before a new class is used.
1808
1809 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1810 assert(k != NULL, "just checking");
1811 assert_locked_or_safepoint(Compile_lock);
1812
1813 // Link into hierachy. Make sure the vtables are initialized before linking into
1814 k->append_to_sibling_list(); // add to superklass/sibling list
1815 k->process_interfaces(THREAD); // handle all "implements" declarations
1816 k->set_init_state(InstanceKlass::loaded);
1817 // Now flush all code that depended on old class hierarchy.
1818 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1819 // Also, first reinitialize vtable because it may have gotten out of synch
1820 // while the new class wasn't connected to the class hierarchy.
1821 CodeCache::flush_dependents_on(k);
1822 }
1823
1824 // ----------------------------------------------------------------------------
1825 // GC support
1826
1827 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1828 // Note: anonymous classes are not in the SD.
1829 bool SystemDictionary::do_unloading(GCTimer* gc_timer,
1830 bool do_cleaning) {
1831
1832 bool unloading_occurred;
1833 {
1834 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1835
1836 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1837 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1838 }
1839
1840 if (unloading_occurred) {
1841 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1842 constraints()->purge_loader_constraints();
1843 resolution_errors()->purge_resolution_errors();
1844 }
1845
1846 {
1847 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1848 // Oops referenced by the protection domain cache table may get unreachable independently
1849 // of the class loader (eg. cached protection domain oops). So we need to
1850 // explicitly unlink them here.
1851 _pd_cache_table->unlink();
1852 }
1853
1854 if (do_cleaning) {
1855 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1856 ResolvedMethodTable::unlink();
1857 }
1858
1859 return unloading_occurred;
1860 }
1861
1862 void SystemDictionary::oops_do(OopClosure* f) {
1863 f->do_oop(&_java_system_loader);
1864 f->do_oop(&_java_platform_loader);
1865 f->do_oop(&_system_loader_lock_obj);
1866 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1867
1868 // Visit extra methods
1869 invoke_method_table()->oops_do(f);
1870 }
1871
1872 // CDS: scan and relocate all classes in the system dictionary.
1873 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1874 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1875 }
1876
1877 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1878 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1879 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1880 it->push(well_known_klass_addr((WKID)id));
1881 }
1882 }
1883
1884 void SystemDictionary::methods_do(void f(Method*)) {
1885 // Walk methods in loaded classes
1886 ClassLoaderDataGraph::methods_do(f);
1887 // Walk method handle intrinsics
1888 invoke_method_table()->methods_do(f);
1889 }
1890
1891 class RemoveClassesClosure : public CLDClosure {
1892 public:
1893 void do_cld(ClassLoaderData* cld) {
1894 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1895 cld->dictionary()->remove_classes_in_error_state();
1896 }
1897 }
1898 };
1899
1900 void SystemDictionary::remove_classes_in_error_state() {
1901 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1902 RemoveClassesClosure rcc;
1903 ClassLoaderDataGraph::cld_do(&rcc);
1904 }
1905
1906 // ----------------------------------------------------------------------------
1907 // Initialization
1908
1909 void SystemDictionary::initialize(TRAPS) {
1910 // Allocate arrays
1911 _placeholders = new PlaceholderTable(_placeholder_table_size);
1912 _number_of_modifications = 0;
1913 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1914 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1915 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1916 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1917
1918 // Allocate private object used as system class loader lock
1919 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1920 // Initialize basic classes
1921 resolve_preloaded_classes(CHECK);
1922 }
1923
1924 // Compact table of directions on the initialization of klasses:
1925 static const short wk_init_info[] = {
1926 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1927 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1928 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1929 | (int)SystemDictionary::option ),
1930 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1931 #undef WK_KLASS_INIT_INFO
1932 0
1933 };
1934
1935 bool SystemDictionary::resolve_wk_klass(WKID id, int init_opt, TRAPS) {
1936 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1937 int info = wk_init_info[id - FIRST_WKID];
1938 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1939 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1940 InstanceKlass** klassp = &_well_known_klasses[id];
1941
1942 bool must_load;
1943 #if INCLUDE_JVMCI
1944 if (EnableJVMCI) {
1945 // If JVMCI is enabled we require its classes to be found.
1946 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1947 } else
1948 #endif
1949 {
1950 must_load = (init_opt < SystemDictionary::Opt);
1951 }
1952
1953 if ((*klassp) == NULL) {
1954 Klass* k;
1955 if (must_load) {
1956 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
1957 } else {
1958 k = resolve_or_null(symbol, CHECK_0); // load optional klass
1959 }
1960 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
1961 }
1962 return ((*klassp) != NULL);
1963 }
1964
1965 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1966 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1967 for (int id = (int)start_id; id < (int)limit_id; id++) {
1968 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1969 int info = wk_init_info[id - FIRST_WKID];
1970 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1971 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1972
1973 resolve_wk_klass((WKID)id, opt, CHECK);
1974 }
1975
1976 // move the starting value forward to the limit:
1977 start_id = limit_id;
1978 }
1979
1980 void SystemDictionary::resolve_preloaded_classes(TRAPS) {
1981 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1982
1983 // Create the ModuleEntry for java.base. This call needs to be done here,
1984 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1985 ClassLoader::classLoader_init2(CHECK);
1986
1987 // Preload commonly used klasses
1988 WKID scan = FIRST_WKID;
1989 // first do Object, then String, Class
1990 #if INCLUDE_CDS
1991 if (UseSharedSpaces) {
1992 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1993 // Initialize the constant pool for the Object_class
1994 Object_klass()->constants()->restore_unshareable_info(CHECK);
1995 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1996 } else
1997 #endif
1998 {
1999 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2000 }
2001
2002 // Calculate offsets for String and Class classes since they are loaded and
2003 // can be used after this point.
2004 java_lang_String::compute_offsets();
2005 java_lang_Class::compute_offsets();
2006
2007 // Fixup mirrors for classes loaded before java.lang.Class.
2008 // These calls iterate over the objects currently in the perm gen
2009 // so calling them at this point is matters (not before when there
2010 // are fewer objects and not later after there are more objects
2011 // in the perm gen.
2012 Universe::initialize_basic_type_mirrors(CHECK);
2013 Universe::fixup_mirrors(CHECK);
2014
2015 // do a bunch more:
2016 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2017
2018 // Preload ref klasses and set reference types
2019 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2020 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2021
2022 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2023 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2024 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2025 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2026 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2027
2028 // JSR 292 classes
2029 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2030 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2031 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2032 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2033 resolve_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2034
2035 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2036 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2037 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2038 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2039 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2040 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2041 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2042 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2043 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2044 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2045
2046 { // Compute whether we should use checkPackageAccess or NOT
2047 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2048 _has_checkPackageAccess = (method != NULL);
2049 }
2050 }
2051
2052 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2053 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2054 BasicType SystemDictionary::box_klass_type(Klass* k) {
2055 assert(k != NULL, "");
2056 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2057 if (_box_klasses[i] == k)
2058 return (BasicType)i;
2059 }
2060 return T_OBJECT;
2061 }
2062
2063 // Constraints on class loaders. The details of the algorithm can be
2064 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2065 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2066 // that the dictionary needs to maintain a set of contraints that
2067 // must be satisfied by all classes in the dictionary.
2068 // if defining is true, then LinkageError if already in dictionary
2069 // if initiating loader, then ok if InstanceKlass matches existing entry
2070
2071 void SystemDictionary::check_constraints(unsigned int d_hash,
2072 InstanceKlass* k,
2073 Handle class_loader,
2074 bool defining,
2075 TRAPS) {
2076 ResourceMark rm(THREAD);
2077 stringStream ss;
2078 bool throwException = false;
2079
2080 {
2081 Symbol *name = k->name();
2082 ClassLoaderData *loader_data = class_loader_data(class_loader);
2083
2084 MutexLocker mu(SystemDictionary_lock, THREAD);
2085
2086 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2087 if (check != NULL) {
2088 // If different InstanceKlass - duplicate class definition,
2089 // else - ok, class loaded by a different thread in parallel.
2090 // We should only have found it if it was done loading and ok to use.
2091 // The dictionary only holds instance classes, placeholders
2092 // also hold array classes.
2093
2094 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2095 if ((defining == true) || (k != check)) {
2096 throwException = true;
2097 ss.print("loader %s", loader_data->loader_name_and_id());
2098 ss.print(" attempted duplicate %s definition for %s. (%s)",
2099 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2100 } else {
2101 return;
2102 }
2103 }
2104
2105 #ifdef ASSERT
2106 Symbol* ph_check = find_placeholder(name, loader_data);
2107 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2108 #endif
2109
2110 if (throwException == false) {
2111 if (constraints()->check_or_update(k, class_loader, name) == false) {
2112 throwException = true;
2113 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2114 ss.print(" wants to load %s %s.",
2115 k->external_kind(), k->external_name());
2116 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2117 if (existing_klass->class_loader() != class_loader()) {
2118 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2119 existing_klass->external_kind(),
2120 existing_klass->class_loader_data()->loader_name_and_id(),
2121 existing_klass->class_in_module_of_loader(false, true));
2122 } else {
2123 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2124 }
2125 }
2126 }
2127 }
2128
2129 // Throw error now if needed (cannot throw while holding
2130 // SystemDictionary_lock because of rank ordering)
2131 if (throwException == true) {
2132 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2133 }
2134 }
2135
2136 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2137 // have been called.
2138 void SystemDictionary::update_dictionary(unsigned int d_hash,
2139 int p_index, unsigned int p_hash,
2140 InstanceKlass* k,
2141 Handle class_loader,
2142 TRAPS) {
2143 // Compile_lock prevents systemDictionary updates during compilations
2144 assert_locked_or_safepoint(Compile_lock);
2145 Symbol* name = k->name();
2146 ClassLoaderData *loader_data = class_loader_data(class_loader);
2147
2148 {
2149 MutexLocker mu1(SystemDictionary_lock, THREAD);
2150
2151 // See whether biased locking is enabled and if so set it for this
2152 // klass.
2153 // Note that this must be done past the last potential blocking
2154 // point / safepoint. We enable biased locking lazily using a
2155 // VM_Operation to iterate the SystemDictionary and installing the
2156 // biasable mark word into each InstanceKlass's prototype header.
2157 // To avoid race conditions where we accidentally miss enabling the
2158 // optimization for one class in the process of being added to the
2159 // dictionary, we must not safepoint after the test of
2160 // BiasedLocking::enabled().
2161 if (UseBiasedLocking && BiasedLocking::enabled()) {
2162 // Set biased locking bit for all loaded classes; it will be
2163 // cleared if revocation occurs too often for this type
2164 // NOTE that we must only do this when the class is initally
2165 // defined, not each time it is referenced from a new class loader
2166 if (oopDesc::equals(k->class_loader(), class_loader())) {
2167 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2168 }
2169 }
2170
2171 // Make a new dictionary entry.
2172 Dictionary* dictionary = loader_data->dictionary();
2173 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2174 if (sd_check == NULL) {
2175 dictionary->add_klass(d_hash, name, k);
2176 notice_modification();
2177 }
2178 #ifdef ASSERT
2179 sd_check = find_class(d_hash, name, dictionary);
2180 assert (sd_check != NULL, "should have entry in dictionary");
2181 // Note: there may be a placeholder entry: for circularity testing
2182 // or for parallel defines
2183 #endif
2184 SystemDictionary_lock->notify_all();
2185 }
2186 }
2187
2188
2189 // Try to find a class name using the loader constraints. The
2190 // loader constraints might know about a class that isn't fully loaded
2191 // yet and these will be ignored.
2192 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2193 Symbol* class_name, Handle class_loader, TRAPS) {
2194
2195 // First see if it has been loaded directly.
2196 // Force the protection domain to be null. (This removes protection checks.)
2197 Handle no_protection_domain;
2198 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2199 no_protection_domain, CHECK_NULL);
2200 if (klass != NULL)
2201 return klass;
2202
2203 // Now look to see if it has been loaded elsewhere, and is subject to
2204 // a loader constraint that would require this loader to return the
2205 // klass that is already loaded.
2206 if (FieldType::is_array(class_name)) {
2207 // For array classes, their Klass*s are not kept in the
2208 // constraint table. The element Klass*s are.
2209 FieldArrayInfo fd;
2210 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2211 if (t != T_OBJECT) {
2212 klass = Universe::typeArrayKlassObj(t);
2213 } else {
2214 MutexLocker mu(SystemDictionary_lock, THREAD);
2215 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2216 }
2217 // If element class already loaded, allocate array klass
2218 if (klass != NULL) {
2219 klass = klass->array_klass_or_null(fd.dimension());
2220 }
2221 } else {
2222 MutexLocker mu(SystemDictionary_lock, THREAD);
2223 // Non-array classes are easy: simply check the constraint table.
2224 klass = constraints()->find_constrained_klass(class_name, class_loader);
2225 }
2226
2227 return klass;
2228 }
2229
2230
2231 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2232 Handle class_loader1,
2233 Handle class_loader2,
2234 Thread* THREAD) {
2235 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2236 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2237
2238 Symbol* constraint_name = NULL;
2239 // Needs to be in same scope as constraint_name in case a Symbol is created and
2240 // assigned to constraint_name.
2241 FieldArrayInfo fd;
2242 if (!FieldType::is_array(class_name)) {
2243 constraint_name = class_name;
2244 } else {
2245 // For array classes, their Klass*s are not kept in the
2246 // constraint table. The element classes are.
2247 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2248 // primitive types always pass
2249 if (t != T_OBJECT) {
2250 return true;
2251 } else {
2252 constraint_name = fd.object_key();
2253 }
2254 }
2255
2256 Dictionary* dictionary1 = loader_data1->dictionary();
2257 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2258
2259 Dictionary* dictionary2 = loader_data2->dictionary();
2260 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2261
2262 {
2263 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2264 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2265 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2266 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2267 klass2, class_loader2);
2268 }
2269 }
2270
2271 // Add entry to resolution error table to record the error when the first
2272 // attempt to resolve a reference to a class has failed.
2273 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2274 Symbol* error, Symbol* message) {
2275 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2276 int index = resolution_errors()->hash_to_index(hash);
2277 {
2278 MutexLocker ml(SystemDictionary_lock, Thread::current());
2279 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2280 }
2281 }
2282
2283 // Delete a resolution error for RedefineClasses for a constant pool is going away
2284 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2285 resolution_errors()->delete_entry(pool);
2286 }
2287
2288 // Lookup resolution error table. Returns error if found, otherwise NULL.
2289 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2290 Symbol** message) {
2291 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2292 int index = resolution_errors()->hash_to_index(hash);
2293 {
2294 MutexLocker ml(SystemDictionary_lock, Thread::current());
2295 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2296 if (entry != NULL) {
2297 *message = entry->message();
2298 return entry->error();
2299 } else {
2300 return NULL;
2301 }
2302 }
2303 }
2304
2305
2306 // Signature constraints ensure that callers and callees agree about
2307 // the meaning of type names in their signatures. This routine is the
2308 // intake for constraints. It collects them from several places:
2309 //
2310 // * LinkResolver::resolve_method (if check_access is true) requires
2311 // that the resolving class (the caller) and the defining class of
2312 // the resolved method (the callee) agree on each type in the
2313 // method's signature.
2314 //
2315 // * LinkResolver::resolve_interface_method performs exactly the same
2316 // checks.
2317 //
2318 // * LinkResolver::resolve_field requires that the constant pool
2319 // attempting to link to a field agree with the field's defining
2320 // class about the type of the field signature.
2321 //
2322 // * klassVtable::initialize_vtable requires that, when a class
2323 // overrides a vtable entry allocated by a superclass, that the
2324 // overriding method (i.e., the callee) agree with the superclass
2325 // on each type in the method's signature.
2326 //
2327 // * klassItable::initialize_itable requires that, when a class fills
2328 // in its itables, for each non-abstract method installed in an
2329 // itable, the method (i.e., the callee) agree with the interface
2330 // on each type in the method's signature.
2331 //
2332 // All those methods have a boolean (check_access, checkconstraints)
2333 // which turns off the checks. This is used from specialized contexts
2334 // such as bootstrapping, dumping, and debugging.
2335 //
2336 // No direct constraint is placed between the class and its
2337 // supertypes. Constraints are only placed along linked relations
2338 // between callers and callees. When a method overrides or implements
2339 // an abstract method in a supertype (superclass or interface), the
2340 // constraints are placed as if the supertype were the caller to the
2341 // overriding method. (This works well, since callers to the
2342 // supertype have already established agreement between themselves and
2343 // the supertype.) As a result of all this, a class can disagree with
2344 // its supertype about the meaning of a type name, as long as that
2345 // class neither calls a relevant method of the supertype, nor is
2346 // called (perhaps via an override) from the supertype.
2347 //
2348 //
2349 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2350 //
2351 // Make sure all class components (including arrays) in the given
2352 // signature will be resolved to the same class in both loaders.
2353 // Returns the name of the type that failed a loader constraint check, or
2354 // NULL if no constraint failed. No exception except OOME is thrown.
2355 // Arrays are not added to the loader constraint table, their elements are.
2356 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2357 Handle loader1, Handle loader2,
2358 bool is_method, TRAPS) {
2359 // Nothing to do if loaders are the same.
2360 if (oopDesc::equals(loader1(), loader2())) {
2361 return NULL;
2362 }
2363
2364 SignatureStream sig_strm(signature, is_method);
2365 while (!sig_strm.is_done()) {
2366 if (sig_strm.is_object()) {
2367 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2368 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2369 return sig;
2370 }
2371 }
2372 sig_strm.next();
2373 }
2374 return NULL;
2375 }
2376
2377
2378 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2379 Symbol* signature,
2380 TRAPS) {
2381 methodHandle empty;
2382 assert(MethodHandles::is_signature_polymorphic(iid) &&
2383 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2384 iid != vmIntrinsics::_invokeGeneric,
2385 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2386
2387 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2388 int index = invoke_method_table()->hash_to_index(hash);
2389 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2390 methodHandle m;
2391 if (spe == NULL || spe->method() == NULL) {
2392 spe = NULL;
2393 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2394 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2395 if (!Arguments::is_interpreter_only()) {
2396 // Generate a compiled form of the MH intrinsic.
2397 AdapterHandlerLibrary::create_native_wrapper(m);
2398 // Check if have the compiled code.
2399 if (!m->has_compiled_code()) {
2400 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2401 "Out of space in CodeCache for method handle intrinsic", empty);
2402 }
2403 }
2404 // Now grab the lock. We might have to throw away the new method,
2405 // if a racing thread has managed to install one at the same time.
2406 {
2407 MutexLocker ml(SystemDictionary_lock, THREAD);
2408 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2409 if (spe == NULL)
2410 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2411 if (spe->method() == NULL)
2412 spe->set_method(m());
2413 }
2414 }
2415
2416 assert(spe != NULL && spe->method() != NULL, "");
2417 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2418 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2419 "MH intrinsic invariant");
2420 return spe->method();
2421 }
2422
2423 // Helper for unpacking the return value from linkMethod and linkCallSite.
2424 static methodHandle unpack_method_and_appendix(Handle mname,
2425 Klass* accessing_klass,
2426 objArrayHandle appendix_box,
2427 Handle* appendix_result,
2428 TRAPS) {
2429 methodHandle empty;
2430 if (mname.not_null()) {
2431 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2432 if (m != NULL) {
2433 oop appendix = appendix_box->obj_at(0);
2434 if (TraceMethodHandles) {
2435 #ifndef PRODUCT
2436 ttyLocker ttyl;
2437 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2438 m->print();
2439 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2440 tty->cr();
2441 #endif //PRODUCT
2442 }
2443 (*appendix_result) = Handle(THREAD, appendix);
2444 // the target is stored in the cpCache and if a reference to this
2445 // MemberName is dropped we need a way to make sure the
2446 // class_loader containing this method is kept alive.
2447 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2448 this_key->record_dependency(m->method_holder());
2449 return methodHandle(THREAD, m);
2450 }
2451 }
2452 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2453 return empty;
2454 }
2455
2456 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2457 Symbol* name,
2458 Symbol* signature,
2459 Klass* accessing_klass,
2460 Handle *appendix_result,
2461 Handle *method_type_result,
2462 TRAPS) {
2463 methodHandle empty;
2464 assert(THREAD->can_call_java() ,"");
2465 Handle method_type =
2466 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2467
2468 int ref_kind = JVM_REF_invokeVirtual;
2469 oop name_oop = StringTable::intern(name, CHECK_(empty));
2470 Handle name_str (THREAD, name_oop);
2471 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2472 assert(appendix_box->obj_at(0) == NULL, "");
2473
2474 // This should not happen. JDK code should take care of that.
2475 if (accessing_klass == NULL || method_type.is_null()) {
2476 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2477 }
2478
2479 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2480 JavaCallArguments args;
2481 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2482 args.push_int(ref_kind);
2483 args.push_oop(Handle(THREAD, klass->java_mirror()));
2484 args.push_oop(name_str);
2485 args.push_oop(method_type);
2486 args.push_oop(appendix_box);
2487 JavaValue result(T_OBJECT);
2488 JavaCalls::call_static(&result,
2489 SystemDictionary::MethodHandleNatives_klass(),
2490 vmSymbols::linkMethod_name(),
2491 vmSymbols::linkMethod_signature(),
2492 &args, CHECK_(empty));
2493 Handle mname(THREAD, (oop) result.get_jobject());
2494 (*method_type_result) = method_type;
2495 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2496 }
2497
2498 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2499 // We must ensure that all class loaders everywhere will reach this class, for any client.
2500 // This is a safe bet for public classes in java.lang, such as Object and String.
2501 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2502 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2503 static bool is_always_visible_class(oop mirror) {
2504 Klass* klass = java_lang_Class::as_Klass(mirror);
2505 if (klass->is_objArray_klass()) {
2506 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2507 }
2508 if (klass->is_typeArray_klass()) {
2509 return true; // primitive array
2510 }
2511 assert(klass->is_instance_klass(), "%s", klass->external_name());
2512 return klass->is_public() &&
2513 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2514 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2515 }
2516
2517
2518 // Return the Java mirror (java.lang.Class instance) for a single-character
2519 // descriptor. This result, when available, is the same as produced by the
2520 // heavier API point of the same name that takes a Symbol.
2521 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2522 return java_lang_Class::primitive_mirror(char2type(signature_char));
2523 }
2524
2525 // Find or construct the Java mirror (java.lang.Class instance) for a
2526 // for the given field type signature, as interpreted relative to the
2527 // given class loader. Handles primitives, void, references, arrays,
2528 // and all other reflectable types, except method types.
2529 // N.B. Code in reflection should use this entry point.
2530 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2531 Klass* accessing_klass,
2532 Handle class_loader,
2533 Handle protection_domain,
2534 SignatureStream::FailureMode failure_mode,
2535 TRAPS) {
2536 Handle empty;
2537
2538 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2539 "one or the other, or perhaps neither");
2540
2541 Symbol* type = signature;
2542
2543 // What we have here must be a valid field descriptor,
2544 // and all valid field descriptors are supported.
2545 // Produce the same java.lang.Class that reflection reports.
2546 if (type->utf8_length() == 1) {
2547
2548 // It's a primitive. (Void has a primitive mirror too.)
2549 char ch = (char) type->byte_at(0);
2550 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2551 return Handle(THREAD, find_java_mirror_for_type(ch));
2552
2553 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2554
2555 // It's a reference type.
2556 if (accessing_klass != NULL) {
2557 class_loader = Handle(THREAD, accessing_klass->class_loader());
2558 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2559 }
2560 Klass* constant_type_klass;
2561 if (failure_mode == SignatureStream::ReturnNull) {
2562 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2563 CHECK_(empty));
2564 } else {
2565 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2566 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2567 throw_error, CHECK_(empty));
2568 }
2569 if (constant_type_klass == NULL) {
2570 return Handle(); // report failure this way
2571 }
2572 Handle mirror(THREAD, constant_type_klass->java_mirror());
2573
2574 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2575 if (accessing_klass != NULL) {
2576 Klass* sel_klass = constant_type_klass;
2577 bool fold_type_to_class = true;
2578 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2579 fold_type_to_class, CHECK_(empty));
2580 }
2581
2582 return mirror;
2583
2584 }
2585
2586 // Fall through to an error.
2587 assert(false, "unsupported mirror syntax");
2588 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2589 }
2590
2591
2592 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2593 // signature, as interpreted relative to the given class loader.
2594 // Because of class loader constraints, all method handle usage must be
2595 // consistent with this loader.
2596 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2597 Klass* accessing_klass,
2598 TRAPS) {
2599 Handle empty;
2600 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2601 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2602 int index = invoke_method_table()->hash_to_index(hash);
2603 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2604 if (spe != NULL && spe->method_type() != NULL) {
2605 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2606 return Handle(THREAD, spe->method_type());
2607 } else if (!THREAD->can_call_java()) {
2608 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2609 return Handle(); // do not attempt from within compiler, unless it was cached
2610 }
2611
2612 Handle class_loader, protection_domain;
2613 if (accessing_klass != NULL) {
2614 class_loader = Handle(THREAD, accessing_klass->class_loader());
2615 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2616 }
2617 bool can_be_cached = true;
2618 int npts = ArgumentCount(signature).size();
2619 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2620 int arg = 0;
2621 Handle rt; // the return type from the signature
2622 ResourceMark rm(THREAD);
2623 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2624 oop mirror = NULL;
2625 if (can_be_cached) {
2626 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2627 mirror = ss.as_java_mirror(Handle(), Handle(),
2628 SignatureStream::ReturnNull, CHECK_(empty));
2629 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2630 // Fall back to accessing_klass context.
2631 can_be_cached = false;
2632 }
2633 }
2634 if (!can_be_cached) {
2635 // Resolve, throwing a real error if it doesn't work.
2636 mirror = ss.as_java_mirror(class_loader, protection_domain,
2637 SignatureStream::NCDFError, CHECK_(empty));
2638 }
2639 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2640 if (ss.at_return_type())
2641 rt = Handle(THREAD, mirror);
2642 else
2643 pts->obj_at_put(arg++, mirror);
2644
2645 // Check accessibility.
2646 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2647 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2648 mirror = NULL; // safety
2649 // Emulate ConstantPool::verify_constant_pool_resolve.
2650 bool fold_type_to_class = true;
2651 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2652 fold_type_to_class, CHECK_(empty));
2653 }
2654 }
2655 assert(arg == npts, "");
2656
2657 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2658 JavaCallArguments args(Handle(THREAD, rt()));
2659 args.push_oop(pts);
2660 JavaValue result(T_OBJECT);
2661 JavaCalls::call_static(&result,
2662 SystemDictionary::MethodHandleNatives_klass(),
2663 vmSymbols::findMethodHandleType_name(),
2664 vmSymbols::findMethodHandleType_signature(),
2665 &args, CHECK_(empty));
2666 Handle method_type(THREAD, (oop) result.get_jobject());
2667
2668 if (can_be_cached) {
2669 // We can cache this MethodType inside the JVM.
2670 MutexLocker ml(SystemDictionary_lock, THREAD);
2671 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2672 if (spe == NULL)
2673 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2674 if (spe->method_type() == NULL) {
2675 spe->set_method_type(method_type());
2676 }
2677 }
2678
2679 // report back to the caller with the MethodType
2680 return method_type;
2681 }
2682
2683 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2684 Klass* accessing_klass,
2685 TRAPS) {
2686 Handle empty;
2687 ResourceMark rm(THREAD);
2688 SignatureStream ss(signature, /*is_method=*/ false);
2689 if (!ss.is_done()) {
2690 Handle class_loader, protection_domain;
2691 if (accessing_klass != NULL) {
2692 class_loader = Handle(THREAD, accessing_klass->class_loader());
2693 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2694 }
2695 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2696 ss.next();
2697 if (ss.is_done()) {
2698 return Handle(THREAD, mirror);
2699 }
2700 }
2701 return empty;
2702 }
2703
2704 // Ask Java code to find or construct a method handle constant.
2705 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2706 int ref_kind, //e.g., JVM_REF_invokeVirtual
2707 Klass* callee,
2708 Symbol* name,
2709 Symbol* signature,
2710 TRAPS) {
2711 Handle empty;
2712 if (caller == NULL) {
2713 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2714 }
2715 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2716 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2717
2718 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2719 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2720 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2721 java_lang_invoke_MemberName::set_name (mname(), name_str());
2722 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2723 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2724
2725 if (ref_kind == JVM_REF_invokeVirtual &&
2726 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2727 // Skip resolution for public signature polymorphic methods such as
2728 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2729 // They require appendix argument which MemberName resolution doesn't handle.
2730 // There's special logic on JDK side to handle them
2731 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2732 } else {
2733 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2734 }
2735
2736 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2737 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2738
2739 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2740 JavaCallArguments args;
2741 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2742 args.push_int(ref_kind);
2743 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2744 args.push_oop(name_str);
2745 args.push_oop(type);
2746 JavaValue result(T_OBJECT);
2747 JavaCalls::call_static(&result,
2748 SystemDictionary::MethodHandleNatives_klass(),
2749 vmSymbols::linkMethodHandleConstant_name(),
2750 vmSymbols::linkMethodHandleConstant_signature(),
2751 &args, CHECK_(empty));
2752 return Handle(THREAD, (oop) result.get_jobject());
2753 }
2754
2755 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2756 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2757 int condy_index,
2758 Handle bootstrap_specifier,
2759 Symbol* name,
2760 Symbol* type,
2761 TRAPS) {
2762 Handle empty;
2763 Handle bsm, info;
2764 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2765 bsm = bootstrap_specifier;
2766 } else {
2767 assert(bootstrap_specifier->is_objArray(), "");
2768 objArrayOop args = (objArrayOop) bootstrap_specifier();
2769 assert(args->length() == 2, "");
2770 bsm = Handle(THREAD, args->obj_at(0));
2771 info = Handle(THREAD, args->obj_at(1));
2772 }
2773 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2774 "caller must supply a valid BSM");
2775
2776 // This should not happen. JDK code should take care of that.
2777 if (caller == NULL) {
2778 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2779 }
2780
2781 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2782
2783 // Resolve the constant type in the context of the caller class
2784 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2785 CHECK_(empty));
2786
2787 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2788 JavaCallArguments args;
2789 args.push_oop(Handle(THREAD, caller->java_mirror()));
2790 args.push_int(condy_index);
2791 args.push_oop(bsm);
2792 args.push_oop(constant_name);
2793 args.push_oop(type_mirror);
2794 args.push_oop(info);
2795 JavaValue result(T_OBJECT);
2796 JavaCalls::call_static(&result,
2797 SystemDictionary::MethodHandleNatives_klass(),
2798 vmSymbols::linkDynamicConstant_name(),
2799 vmSymbols::linkDynamicConstant_signature(),
2800 &args, CHECK_(empty));
2801
2802 return Handle(THREAD, (oop) result.get_jobject());
2803 }
2804
2805 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2806 // name and signature, as interpreted relative to the given class loader.
2807 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2808 int indy_index,
2809 Handle bootstrap_specifier,
2810 Symbol* name,
2811 Symbol* type,
2812 Handle *appendix_result,
2813 Handle *method_type_result,
2814 TRAPS) {
2815 methodHandle empty;
2816 Handle bsm, info;
2817 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2818 bsm = bootstrap_specifier;
2819 } else {
2820 objArrayOop args = (objArrayOop) bootstrap_specifier();
2821 assert(args->length() == 2, "");
2822 bsm = Handle(THREAD, args->obj_at(0));
2823 info = Handle(THREAD, args->obj_at(1));
2824 }
2825 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2826 "caller must supply a valid BSM");
2827
2828 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2829 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2830
2831 // This should not happen. JDK code should take care of that.
2832 if (caller == NULL || method_type.is_null()) {
2833 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2834 }
2835
2836 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2837 assert(appendix_box->obj_at(0) == NULL, "");
2838
2839 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2840 JavaCallArguments args;
2841 args.push_oop(Handle(THREAD, caller->java_mirror()));
2842 args.push_int(indy_index);
2843 args.push_oop(bsm);
2844 args.push_oop(method_name);
2845 args.push_oop(method_type);
2846 args.push_oop(info);
2847 args.push_oop(appendix_box);
2848 JavaValue result(T_OBJECT);
2849 JavaCalls::call_static(&result,
2850 SystemDictionary::MethodHandleNatives_klass(),
2851 vmSymbols::linkCallSite_name(),
2852 vmSymbols::linkCallSite_signature(),
2853 &args, CHECK_(empty));
2854 Handle mname(THREAD, (oop) result.get_jobject());
2855 (*method_type_result) = method_type;
2856 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2857 }
2858
2859 // Protection domain cache table handling
2860
2861 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2862 return _pd_cache_table->get(protection_domain);
2863 }
2864
2865 #if INCLUDE_CDS
2866 void SystemDictionary::reorder_dictionary_for_sharing() {
2867 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2868 }
2869 #endif
2870
2871 size_t SystemDictionary::count_bytes_for_buckets() {
2872 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2873 }
2874
2875 size_t SystemDictionary::count_bytes_for_table() {
2876 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2877 }
2878
2879 void SystemDictionary::copy_buckets(char* top, char* end) {
2880 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2881 }
2882
2883 void SystemDictionary::copy_table(char* top, char* end) {
2884 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2885 }
2886
2887 // ----------------------------------------------------------------------------
2888 void SystemDictionary::print_shared(outputStream *st) {
2889 shared_dictionary()->print_on(st);
2890 }
2891
2892 void SystemDictionary::print_on(outputStream *st) {
2893 if (shared_dictionary() != NULL) {
2894 st->print_cr("Shared Dictionary");
2895 shared_dictionary()->print_on(st);
2896 st->cr();
2897 }
2898
2899 GCMutexLocker mu(SystemDictionary_lock);
2900
2901 ClassLoaderDataGraph::print_dictionary(st);
2902
2903 // Placeholders
2904 placeholders()->print_on(st);
2905 st->cr();
2906
2907 // loader constraints - print under SD_lock
2908 constraints()->print_on(st);
2909 st->cr();
2910
2911 _pd_cache_table->print_on(st);
2912 st->cr();
2913 }
2914
2915 void SystemDictionary::verify() {
2916 guarantee(constraints() != NULL,
2917 "Verify of loader constraints failed");
2918 guarantee(placeholders()->number_of_entries() >= 0,
2919 "Verify of placeholders failed");
2920
2921 GCMutexLocker mu(SystemDictionary_lock);
2922
2923 // Verify dictionary
2924 ClassLoaderDataGraph::verify_dictionary();
2925
2926 placeholders()->verify();
2927
2928 // Verify constraint table
2929 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2930 constraints()->verify(placeholders());
2931
2932 _pd_cache_table->verify();
2933 }
2934
2935 void SystemDictionary::dump(outputStream *st, bool verbose) {
2936 assert_locked_or_safepoint(SystemDictionary_lock);
2937 if (verbose) {
2938 print_on(st);
2939 } else {
2940 if (shared_dictionary() != NULL) {
2941 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2942 }
2943 ClassLoaderDataGraph::print_dictionary_statistics(st);
2944 placeholders()->print_table_statistics(st, "Placeholder Table");
2945 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2946 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2947 }
2948 }
2949
2950 // Utility for dumping dictionaries.
2951 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2952 DCmdWithParser(output, heap),
2953 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2954 "BOOLEAN", false, "false") {
2955 _dcmdparser.add_dcmd_option(&_verbose);
2956 }
2957
2958 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2959 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2960 _verbose.value());
2961 VMThread::execute(&dumper);
2962 }
2963
2964 int SystemDictionaryDCmd::num_arguments() {
2965 ResourceMark rm;
2966 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2967 if (dcmd != NULL) {
2968 DCmdMark mark(dcmd);
2969 return dcmd->_dcmdparser.num_arguments();
2970 } else {
2971 return 0;
2972 }
2973 }
2974
2975 class CombineDictionariesClosure : public CLDClosure {
2976 private:
2977 Dictionary* _master_dictionary;
2978 public:
2979 CombineDictionariesClosure(Dictionary* master_dictionary) :
2980 _master_dictionary(master_dictionary) {}
2981 void do_cld(ClassLoaderData* cld) {
2982 ResourceMark rm;
2983 if (cld->is_anonymous()) {
2984 return;
2985 }
2986 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2987 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
2988 Dictionary* curr_dictionary = cld->dictionary();
2989 DictionaryEntry* p = curr_dictionary->bucket(i);
2990 while (p != NULL) {
2991 Symbol* name = p->instance_klass()->name();
2992 unsigned int d_hash = _master_dictionary->compute_hash(name);
2993 int d_index = _master_dictionary->hash_to_index(d_hash);
2994 DictionaryEntry* next = p->next();
2995 if (p->literal()->class_loader_data() != cld) {
2996 // This is an initiating class loader entry; don't use it
2997 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
2998 curr_dictionary->free_entry(p);
2999 } else {
3000 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3001 curr_dictionary->unlink_entry(p);
3002 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3003 _master_dictionary->add_entry(d_index, p);
3004 }
3005 p = next;
3006 }
3007 *curr_dictionary->bucket_addr(i) = NULL;
3008 }
3009 }
3010 }
3011 };
3012
3013 // Combining platform and system loader dictionaries into boot loader dictionary.
3014 // During run time, we only have one shared dictionary.
3015 void SystemDictionary::combine_shared_dictionaries() {
3016 assert(DumpSharedSpaces, "dump time only");
3017 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3018 CombineDictionariesClosure cdc(master_dictionary);
3019 ClassLoaderDataGraph::cld_do(&cdc);
3020
3021 // These tables are no longer valid or necessary. Keeping them around will
3022 // cause SystemDictionary::verify() to fail. Let's empty them.
3023 _placeholders = new PlaceholderTable(_placeholder_table_size);
3024 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3025
3026 NOT_PRODUCT(SystemDictionary::verify());
3027 }
3028
3029 void SystemDictionary::initialize_oop_storage() {
3030 _vm_weak_oop_storage =
3031 new OopStorage("VM Weak Oop Handles",
3032 VMWeakAlloc_lock,
3033 VMWeakActive_lock);
3034 }
3035
3036 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3037 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3038 return _vm_weak_oop_storage;
3039 }