1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/protectionDomainCache.hpp"
39 #include "classfile/resolutionErrors.hpp"
40 #include "classfile/stringTable.hpp"
41 #include "classfile/systemDictionary.hpp"
42 #include "classfile/vmSymbols.hpp"
43 #include "code/codeCache.hpp"
44 #include "compiler/compileBroker.hpp"
45 #include "gc/shared/gcLocker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "interpreter/bytecodeStream.hpp"
48 #include "interpreter/interpreter.hpp"
49 #include "logging/log.hpp"
50 #include "logging/logStream.hpp"
51 #include "memory/filemap.hpp"
52 #include "memory/metaspaceClosure.hpp"
53 #include "memory/oopFactory.hpp"
54 #include "memory/resourceArea.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/instanceRefKlass.hpp"
57 #include "oops/klass.inline.hpp"
58 #include "oops/methodData.hpp"
59 #include "oops/objArrayKlass.hpp"
60 #include "oops/objArrayOop.inline.hpp"
61 #include "oops/oop.inline.hpp"
62 #include "oops/symbol.hpp"
63 #include "oops/typeArrayKlass.hpp"
64 #include "prims/jvm.h"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/arguments_ext.hpp"
70 #include "runtime/biasedLocking.hpp"
71 #include "runtime/fieldType.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/java.hpp"
74 #include "runtime/javaCalls.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.inline.hpp"
77 #include "runtime/signature.hpp"
78 #include "services/classLoadingService.hpp"
79 #include "services/diagnosticCommand.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/tracing.hpp"
82 #include "utilities/macros.hpp"
83 #if INCLUDE_CDS
84 #include "classfile/sharedClassUtil.hpp"
85 #include "classfile/systemDictionaryShared.hpp"
86 #endif
87 #if INCLUDE_JVMCI
88 #include "jvmci/jvmciRuntime.hpp"
89 #endif
90
91 PlaceholderTable* SystemDictionary::_placeholders = NULL;
92 Dictionary* SystemDictionary::_shared_dictionary = NULL;
93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
97
98 int SystemDictionary::_number_of_modifications = 0;
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107 oop SystemDictionary::_java_platform_loader = NULL;
108
109 bool SystemDictionary::_has_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
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 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
151 }
152
153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
155 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
156 }
157
158 // ----------------------------------------------------------------------------
159 // Parallel class loading check
160
161 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
162 if (UnsyncloadClass || class_loader.is_null()) return true;
163 if (AlwaysLockClassLoader) return false;
164 return java_lang_ClassLoader::parallelCapable(class_loader());
165 }
166 // ----------------------------------------------------------------------------
167 // ParallelDefineClass flag does not apply to bootclass loader
168 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
169 if (class_loader.is_null()) return false;
170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
171 return true;
172 }
173 return false;
174 }
175
176 // Returns true if the passed class loader is the builtin application class loader
177 // or a custom system class loader. A customer system class loader can be
178 // specified via -Djava.system.class.loader.
179 bool SystemDictionary::is_system_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
184 class_loader == _java_system_loader);
185 }
186
187 // Returns true if the passed class loader is the platform class loader.
188 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
189 if (class_loader == NULL) {
190 return false;
191 }
192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
193 }
194
195 // ----------------------------------------------------------------------------
196 // Resolving of classes
197
198 // Forwards to resolve_or_null
199
200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
202 if (HAS_PENDING_EXCEPTION || klass == NULL) {
203 // can return a null klass
204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
205 }
206 return klass;
207 }
208
209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
210 bool throw_error,
211 Klass* klass, TRAPS) {
212 if (HAS_PENDING_EXCEPTION) {
213 // If we have a pending exception we forward it to the caller, unless throw_error is true,
214 // in which case we have to check whether the pending exception is a ClassNotFoundException,
215 // and if so convert it to a NoClassDefFoundError
216 // And chain the original ClassNotFoundException
217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
218 ResourceMark rm(THREAD);
219 assert(klass == NULL, "Should not have result with exception pending");
220 Handle e(THREAD, PENDING_EXCEPTION);
221 CLEAR_PENDING_EXCEPTION;
222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
223 } else {
224 return NULL;
225 }
226 }
227 // Class not found, throw appropriate error or exception depending on value of throw_error
228 if (klass == NULL) {
229 ResourceMark rm(THREAD);
230 if (throw_error) {
231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
232 } else {
233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
234 }
235 }
236 return klass;
237 }
238
239
240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
241 bool throw_error, TRAPS)
242 {
243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
244 }
245
246
247 // Forwards to resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 assert(THREAD->can_call_java(),
251 "can not load classes with compiler thread: class=%s, classloader=%s",
252 class_name->as_C_string(),
253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
254 if (FieldType::is_array(class_name)) {
255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 } else if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2, CHECK_NULL);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* class_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for CDS dump time.
348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 int d_index = dictionary->hash_to_index(d_hash);
375 unsigned int p_hash = placeholders()->compute_hash(child_name);
376 int p_index = placeholders()->hash_to_index(p_hash);
377 // can't throw error holding a lock
378 bool child_already_loaded = false;
379 bool throw_circularity_error = false;
380 {
381 MutexLocker mu(SystemDictionary_lock, THREAD);
382 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
383 Klass* quicksuperk;
384 // to support // loading: if child done loading, just return superclass
385 // if class_name, & class_loader don't match:
386 // if initial define, SD update will give LinkageError
387 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
388 // so we don't throw an exception here.
389 // see: nsk redefclass014 & java.lang.instrument Instrument032
390 if ((childk != NULL ) && (is_superclass) &&
391 ((quicksuperk = childk->super()) != NULL) &&
392
393 ((quicksuperk->name() == class_name) &&
394 (quicksuperk->class_loader() == class_loader()))) {
395 return quicksuperk;
396 } else {
397 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
398 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
399 throw_circularity_error = true;
400 }
401 }
402 if (!throw_circularity_error) {
403 // Be careful not to exit resolve_super
404 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
405 }
406 }
407 if (throw_circularity_error) {
408 ResourceMark rm(THREAD);
409 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
410 }
411
412 // java.lang.Object should have been found above
413 assert(class_name != NULL, "null super class for resolving");
414 // Resolve the super class or interface, check results on return
415 Klass* superk = SystemDictionary::resolve_or_null(class_name,
416 class_loader,
417 protection_domain,
418 THREAD);
419
420 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
421 // It is no longer necessary to keep the placeholder table alive until update_dictionary
422 // or error. GC used to walk the placeholder table as strong roots.
423 // The instanceKlass is kept alive because the class loader is on the stack,
424 // which keeps the loader_data alive, as well as all instanceKlasses in
425 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
426 {
427 MutexLocker mu(SystemDictionary_lock, THREAD);
428 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
429 SystemDictionary_lock->notify_all();
430 }
431 if (HAS_PENDING_EXCEPTION || superk == NULL) {
432 // can null superk
433 superk = handle_resolution_exception(class_name, true, superk, THREAD);
434 }
435
436 return superk;
437 }
438
439 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
440 Handle class_loader,
441 Handle protection_domain,
442 TRAPS) {
443 if(!has_checkPackageAccess()) return;
444
445 // Now we have to call back to java to check if the initating class has access
446 JavaValue result(T_VOID);
447 LogTarget(Debug, protectiondomain) lt;
448 if (lt.is_enabled()) {
449 ResourceMark rm;
450 // Print out trace information
451 LogStream ls(lt);
452 ls.print_cr("Checking package access");
453 ls.print("class loader: "); class_loader()->print_value_on(&ls);
454 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
455 ls.print(" loading: "); klass->print_value_on(&ls);
456 ls.cr();
457 }
458
459 // This handle and the class_loader handle passed in keeps this class from
460 // being unloaded through several GC points.
461 // The class_loader handle passed in is the initiating loader.
462 Handle mirror(THREAD, klass->java_mirror());
463
464 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
465 JavaCalls::call_special(&result,
466 class_loader,
467 system_loader,
468 vmSymbols::checkPackageAccess_name(),
469 vmSymbols::class_protectiondomain_signature(),
470 mirror,
471 protection_domain,
472 THREAD);
473
474 if (HAS_PENDING_EXCEPTION) {
475 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
476 } else {
477 log_debug(protectiondomain)("granted");
478 }
479
480 if (HAS_PENDING_EXCEPTION) return;
481
482 // If no exception has been thrown, we have validated the protection domain
483 // Insert the protection domain of the initiating class into the set.
484 {
485 ClassLoaderData* loader_data = class_loader_data(class_loader);
486 Dictionary* dictionary = loader_data->dictionary();
487
488 Symbol* kn = klass->name();
489 unsigned int d_hash = dictionary->compute_hash(kn);
490 int d_index = dictionary->hash_to_index(d_hash);
491
492 MutexLocker mu(SystemDictionary_lock, THREAD);
493 dictionary->add_protection_domain(d_index, d_hash, klass,
494 protection_domain, THREAD);
495 }
496 }
497
498 // We only get here if this thread finds that another thread
499 // has already claimed the placeholder token for the current operation,
500 // but that other thread either never owned or gave up the
501 // object lock
502 // Waits on SystemDictionary_lock to indicate placeholder table updated
503 // On return, caller must recheck placeholder table state
504 //
505 // We only get here if
506 // 1) custom classLoader, i.e. not bootstrap classloader
507 // 2) UnsyncloadClass not set
508 // 3) custom classLoader has broken the class loader objectLock
509 // so another thread got here in parallel
510 //
511 // lockObject must be held.
512 // Complicated dance due to lock ordering:
513 // Must first release the classloader object lock to
514 // allow initial definer to complete the class definition
515 // and to avoid deadlock
516 // Reclaim classloader lock object with same original recursion count
517 // Must release SystemDictionary_lock after notify, since
518 // class loader lock must be claimed before SystemDictionary_lock
519 // to prevent deadlocks
520 //
521 // The notify allows applications that did an untimed wait() on
522 // the classloader object lock to not hang.
523 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
524 assert_lock_strong(SystemDictionary_lock);
525
526 bool calledholdinglock
527 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
528 assert(calledholdinglock,"must hold lock for notify");
529 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
530 ObjectSynchronizer::notifyall(lockObject, THREAD);
531 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
532 SystemDictionary_lock->wait();
533 SystemDictionary_lock->unlock();
534 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
535 SystemDictionary_lock->lock();
536 }
537
538 // If the class in is in the placeholder table, class loading is in progress
539 // For cases where the application changes threads to load classes, it
540 // is critical to ClassCircularity detection that we try loading
541 // the superclass on the same thread internally, so we do parallel
542 // super class loading here.
543 // This also is critical in cases where the original thread gets stalled
544 // even in non-circularity situations.
545 // Note: must call resolve_super_or_fail even if null super -
546 // to force placeholder entry creation for this class for circularity detection
547 // Caller must check for pending exception
548 // Returns non-null Klass* if other thread has completed load
549 // and we are done,
550 // If return null Klass* and no pending exception, the caller must load the class
551 InstanceKlass* SystemDictionary::handle_parallel_super_load(
552 Symbol* name, Symbol* superclassname, Handle class_loader,
553 Handle protection_domain, Handle lockObject, TRAPS) {
554
555 ClassLoaderData* loader_data = class_loader_data(class_loader);
556 Dictionary* dictionary = loader_data->dictionary();
557 unsigned int d_hash = dictionary->compute_hash(name);
558 int d_index = dictionary->hash_to_index(d_hash);
559 unsigned int p_hash = placeholders()->compute_hash(name);
560 int p_index = placeholders()->hash_to_index(p_hash);
561
562 // superk is not used, resolve_super called for circularity check only
563 // This code is reached in two situations. One if this thread
564 // is loading the same class twice (e.g. ClassCircularity, or
565 // java.lang.instrument).
566 // The second is if another thread started the resolve_super first
567 // and has not yet finished.
568 // In both cases the original caller will clean up the placeholder
569 // entry on error.
570 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
571 superclassname,
572 class_loader,
573 protection_domain,
574 true,
575 CHECK_NULL);
576
577 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
578 // Serial class loaders and bootstrap classloader do wait for superclass loads
579 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
580 MutexLocker mu(SystemDictionary_lock, THREAD);
581 // Check if classloading completed while we were loading superclass or waiting
582 return find_class(d_index, d_hash, name, dictionary);
583 }
584
585 // must loop to both handle other placeholder updates
586 // and spurious notifications
587 bool super_load_in_progress = true;
588 PlaceholderEntry* placeholder;
589 while (super_load_in_progress) {
590 MutexLocker mu(SystemDictionary_lock, THREAD);
591 // Check if classloading completed while we were loading superclass or waiting
592 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
593 if (check != NULL) {
594 // Klass is already loaded, so just return it
595 return check;
596 } else {
597 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
598 if (placeholder && placeholder->super_load_in_progress() ){
599 // Before UnsyncloadClass:
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,
628 const InstanceKlass* k,
629 const ClassLoaderData* init_cld) {
630 #if INCLUDE_TRACE
631 assert(event != NULL, "invariant");
632 assert(k != NULL, "invariant");
633 if (event->should_commit()) {
634 event->set_loadedClass(k);
635 event->set_definingClassLoader(k->class_loader_data());
636 event->set_initiatingClassLoader(init_cld);
637 event->commit();
638 }
639 #endif // INCLUDE_TRACE
640 }
641
642 static void class_define_event(InstanceKlass* k,
643 const ClassLoaderData* def_cld) {
644 #if INCLUDE_TRACE
645 EventClassDefine event;
646 if (event.should_commit()) {
647 event.set_definedClass(k);
648 event.set_definingClassLoader(def_cld);
649 event.commit();
650 }
651 #endif // INCLUDE_TRACE
652 }
653
654 // Be careful when modifying this code: once you have run
655 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
656 // you need to find_and_remove it before returning.
657 // So be careful to not exit with a CHECK_ macro betweeen these calls.
658 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
659 Handle class_loader,
660 Handle protection_domain,
661 TRAPS) {
662 assert(name != NULL && !FieldType::is_array(name) &&
663 !FieldType::is_obj(name), "invalid class name");
664
665 EventClassLoad class_load_start_event;
666
667 HandleMark hm(THREAD);
668
669 // Fix for 4474172; see evaluation for more details
670 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
671 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
672 Dictionary* dictionary = loader_data->dictionary();
673
674 // Do lookup to see if class already exist and the protection domain
675 // has the right access
676 // This call uses find which checks protection domain already matches
677 // All subsequent calls use find_class, and set has_loaded_class so that
678 // before we return a result we call out to java to check for valid protection domain
679 // to allow returning the Klass* and add it to the pd_set if it is valid
680 unsigned int d_hash = dictionary->compute_hash(name);
681 int d_index = dictionary->hash_to_index(d_hash);
682 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
683 if (probe != NULL) return probe;
684
685
686 // Non-bootstrap class loaders will call out to class loader and
687 // define via jvm/jni_DefineClass which will acquire the
688 // class loader object lock to protect against multiple threads
689 // defining the class in parallel by accident.
690 // This lock must be acquired here so the waiter will find
691 // any successful result in the SystemDictionary and not attempt
692 // the define
693 // ParallelCapable Classloaders and the bootstrap classloader,
694 // or all classloaders with UnsyncloadClass do not acquire lock here
695 bool DoObjectLock = true;
696 if (is_parallelCapable(class_loader)) {
697 DoObjectLock = false;
698 }
699
700 unsigned int p_hash = placeholders()->compute_hash(name);
701 int p_index = placeholders()->hash_to_index(p_hash);
702
703 // Class is not in SystemDictionary so we have to do loading.
704 // Make sure we are synchronized on the class loader before we proceed
705 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
706 check_loader_lock_contention(lockObject, THREAD);
707 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
708
709 // Check again (after locking) if class already exist in SystemDictionary
710 bool class_has_been_loaded = false;
711 bool super_load_in_progress = false;
712 bool havesupername = false;
713 InstanceKlass* k = NULL;
714 PlaceholderEntry* placeholder;
715 Symbol* superclassname = NULL;
716
717 {
718 MutexLocker mu(SystemDictionary_lock, THREAD);
719 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
720 if (check != NULL) {
721 // Klass is already loaded, so just return it
722 class_has_been_loaded = true;
723 k = check;
724 } else {
725 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
726 if (placeholder && placeholder->super_load_in_progress()) {
727 super_load_in_progress = true;
728 if (placeholder->havesupername() == true) {
729 superclassname = placeholder->supername();
730 havesupername = true;
731 }
732 }
733 }
734 }
735
736 // If the class is in the placeholder table, class loading is in progress
737 if (super_load_in_progress && havesupername==true) {
738 k = handle_parallel_super_load(name,
739 superclassname,
740 class_loader,
741 protection_domain,
742 lockObject, THREAD);
743 if (HAS_PENDING_EXCEPTION) {
744 return NULL;
745 }
746 if (k != NULL) {
747 class_has_been_loaded = true;
748 }
749 }
750
751 bool throw_circularity_error = false;
752 if (!class_has_been_loaded) {
753 bool load_instance_added = false;
754
755 // add placeholder entry to record loading instance class
756 // Five cases:
757 // All cases need to prevent modifying bootclasssearchpath
758 // in parallel with a classload of same classname
759 // Redefineclasses uses existence of the placeholder for the duration
760 // of the class load to prevent concurrent redefinition of not completely
761 // defined classes.
762 // case 1. traditional classloaders that rely on the classloader object lock
763 // - no other need for LOAD_INSTANCE
764 // case 2. traditional classloaders that break the classloader object lock
765 // as a deadlock workaround. Detection of this case requires that
766 // this check is done while holding the classloader object lock,
767 // and that lock is still held when calling classloader's loadClass.
768 // For these classloaders, we ensure that the first requestor
769 // completes the load and other requestors wait for completion.
770 // case 3. UnsyncloadClass - don't use objectLocker
771 // With this flag, we allow parallel classloading of a
772 // class/classloader pair
773 // case4. Bootstrap classloader - don't own objectLocker
774 // This classloader supports parallelism at the classloader level,
775 // but only allows a single load of a class/classloader pair.
776 // No performance benefit and no deadlock issues.
777 // case 5. parallelCapable user level classloaders - without objectLocker
778 // Allow parallel classloading of a class/classloader pair
779
780 {
781 MutexLocker mu(SystemDictionary_lock, THREAD);
782 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
783 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
784 if (oldprobe) {
785 // only need check_seen_thread once, not on each loop
786 // 6341374 java/lang/Instrument with -Xcomp
787 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
788 throw_circularity_error = true;
789 } else {
790 // case 1: traditional: should never see load_in_progress.
791 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
792
793 // case 4: bootstrap classloader: prevent futile classloading,
794 // wait on first requestor
795 if (class_loader.is_null()) {
796 SystemDictionary_lock->wait();
797 } else {
798 // case 2: traditional with broken classloader lock. wait on first
799 // requestor.
800 double_lock_wait(lockObject, THREAD);
801 }
802 // Check if classloading completed while we were waiting
803 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
804 if (check != NULL) {
805 // Klass is already loaded, so just return it
806 k = check;
807 class_has_been_loaded = true;
808 }
809 // check if other thread failed to load and cleaned up
810 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
811 }
812 }
813 }
814 }
815 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
816 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
817 // LOAD_INSTANCE in parallel
818
819 if (!throw_circularity_error && !class_has_been_loaded) {
820 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
821 load_instance_added = true;
822 // For class loaders that do not acquire the classloader object lock,
823 // if they did not catch another thread holding LOAD_INSTANCE,
824 // need a check analogous to the acquire ObjectLocker/find_class
825 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
826 // one final check if the load has already completed
827 // class loaders holding the ObjectLock shouldn't find the class here
828 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
829 if (check != NULL) {
830 // Klass is already loaded, so return it after checking/adding protection domain
831 k = check;
832 class_has_been_loaded = true;
833 }
834 }
835 }
836
837 // must throw error outside of owning lock
838 if (throw_circularity_error) {
839 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
840 ResourceMark rm(THREAD);
841 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
842 }
843
844 if (!class_has_been_loaded) {
845
846 // Do actual loading
847 k = load_instance_class(name, class_loader, THREAD);
848
849 // For UnsyncloadClass only
850 // If they got a linkageError, check if a parallel class load succeeded.
851 // If it did, then for bytecode resolution the specification requires
852 // that we return the same result we did for the other thread, i.e. the
853 // successfully loaded InstanceKlass
854 // Should not get here for classloaders that support parallelism
855 // with the new cleaner mechanism, even with AllowParallelDefineClass
856 // Bootstrap goes through here to allow for an extra guarantee check
857 if (UnsyncloadClass || (class_loader.is_null())) {
858 if (k == NULL && HAS_PENDING_EXCEPTION
859 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
860 MutexLocker mu(SystemDictionary_lock, THREAD);
861 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
862 if (check != NULL) {
863 // Klass is already loaded, so just use it
864 k = check;
865 CLEAR_PENDING_EXCEPTION;
866 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
867 }
868 }
869 }
870
871 // If everything was OK (no exceptions, no null return value), and
872 // class_loader is NOT the defining loader, do a little more bookkeeping.
873 if (!HAS_PENDING_EXCEPTION && k != NULL &&
874 k->class_loader() != class_loader()) {
875
876 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
877
878 // Need to check for a PENDING_EXCEPTION again; check_constraints
879 // can throw and doesn't use the CHECK macro.
880 if (!HAS_PENDING_EXCEPTION) {
881 { // Grabbing the Compile_lock prevents systemDictionary updates
882 // during compilations.
883 MutexLocker mu(Compile_lock, THREAD);
884 update_dictionary(d_index, d_hash, p_index, p_hash,
885 k, class_loader, THREAD);
886 }
887
888 if (JvmtiExport::should_post_class_load()) {
889 Thread *thread = THREAD;
890 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
891 JvmtiExport::post_class_load((JavaThread *) thread, k);
892 }
893 }
894 }
895 } // load_instance_class
896
897 if (load_instance_added == true) {
898 // clean up placeholder entries for LOAD_INSTANCE success or error
899 // This brackets the SystemDictionary updates for both defining
900 // and initiating loaders
901 MutexLocker mu(SystemDictionary_lock, THREAD);
902 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
903 SystemDictionary_lock->notify_all();
904 }
905 }
906
907 if (HAS_PENDING_EXCEPTION || k == NULL) {
908 return NULL;
909 }
910
911 post_class_load_event(&class_load_start_event, k, loader_data);
912
913 #ifdef ASSERT
914 {
915 ClassLoaderData* loader_data = k->class_loader_data();
916 MutexLocker mu(SystemDictionary_lock, THREAD);
917 Klass* kk = find_class(name, loader_data);
918 assert(kk == k, "should be present in dictionary");
919 }
920 #endif
921
922 // return if the protection domain in NULL
923 if (protection_domain() == NULL) return k;
924
925 // Check the protection domain has the right access
926 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
927 protection_domain)) {
928 return k;
929 }
930
931 // Verify protection domain. If it fails an exception is thrown
932 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
933
934 return k;
935 }
936
937
938 // This routine does not lock the system dictionary.
939 //
940 // Since readers don't hold a lock, we must make sure that system
941 // dictionary entries are only removed at a safepoint (when only one
942 // thread is running), and are added to in a safe way (all links must
943 // be updated in an MT-safe manner).
944 //
945 // Callers should be aware that an entry could be added just after
946 // _dictionary->bucket(index) is read here, so the caller will not see
947 // the new entry.
948
949 Klass* SystemDictionary::find(Symbol* class_name,
950 Handle class_loader,
951 Handle protection_domain,
952 TRAPS) {
953
954 // The result of this call should be consistent with the result
955 // of the call to resolve_instance_class_or_null().
956 // See evaluation 6790209 and 4474172 for more details.
957 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
958 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
959
960 if (loader_data == NULL) {
961 // If the ClassLoaderData has not been setup,
962 // then the class loader has no entries in the dictionary.
963 return NULL;
964 }
965
966 Dictionary* dictionary = loader_data->dictionary();
967 unsigned int d_hash = dictionary->compute_hash(class_name);
968 int d_index = dictionary->hash_to_index(d_hash);
969 return dictionary->find(d_index, d_hash, class_name,
970 protection_domain);
971 }
972
973
974 // Look for a loaded instance or array klass by name. Do not do any loading.
975 // return NULL in case of error.
976 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
977 Handle class_loader,
978 Handle protection_domain,
979 TRAPS) {
980 Klass* k = NULL;
981 assert(class_name != NULL, "class name must be non NULL");
982
983 if (FieldType::is_array(class_name)) {
984 // The name refers to an array. Parse the name.
985 // dimension and object_key in FieldArrayInfo are assigned as a
986 // side-effect of this call
987 FieldArrayInfo fd;
988 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
989 if (t != T_OBJECT) {
990 k = Universe::typeArrayKlassObj(t);
991 } else {
992 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
993 }
994 if (k != NULL) {
995 k = k->array_klass_or_null(fd.dimension());
996 }
997 } else {
998 k = find(class_name, class_loader, protection_domain, THREAD);
999 }
1000 return k;
1001 }
1002
1003 // Note: this method is much like resolve_from_stream, but
1004 // does not publish the classes via the SystemDictionary.
1005 // Handles unsafe_DefineAnonymousClass and redefineclasses
1006 // RedefinedClasses do not add to the class hierarchy
1007 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1008 Handle class_loader,
1009 Handle protection_domain,
1010 ClassFileStream* st,
1011 const InstanceKlass* host_klass,
1012 GrowableArray<Handle>* cp_patches,
1013 TRAPS) {
1014
1015 EventClassLoad class_load_start_event;
1016
1017 ClassLoaderData* loader_data;
1018 if (host_klass != NULL) {
1019 // Create a new CLD for anonymous class, that uses the same class loader
1020 // as the host_klass
1021 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1022 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1023 } else {
1024 loader_data = ClassLoaderData::class_loader_data(class_loader());
1025 }
1026
1027 assert(st != NULL, "invariant");
1028 assert(st->need_verify(), "invariant");
1029
1030 // Parse stream and create a klass.
1031 // Note that we do this even though this klass might
1032 // already be present in the SystemDictionary, otherwise we would not
1033 // throw potential ClassFormatErrors.
1034
1035 InstanceKlass* k = KlassFactory::create_from_stream(st,
1036 class_name,
1037 loader_data,
1038 protection_domain,
1039 host_klass,
1040 cp_patches,
1041 CHECK_NULL);
1042
1043 if (host_klass != NULL && k != NULL) {
1044 // If it's anonymous, initialize it now, since nobody else will.
1045
1046 {
1047 MutexLocker mu_r(Compile_lock, THREAD);
1048
1049 // Add to class hierarchy, initialize vtables, and do possible
1050 // deoptimizations.
1051 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1052
1053 // But, do not add to dictionary.
1054
1055 // compiled code dependencies need to be validated anyway
1056 notice_modification();
1057 }
1058
1059 // Rewrite and patch constant pool here.
1060 k->link_class(CHECK_NULL);
1061 if (cp_patches != NULL) {
1062 k->constants()->patch_resolved_references(cp_patches);
1063 }
1064 k->eager_initialize(CHECK_NULL);
1065
1066 // notify jvmti
1067 if (JvmtiExport::should_post_class_load()) {
1068 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1069 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1070 }
1071
1072 post_class_load_event(&class_load_start_event, k, loader_data);
1073 }
1074 assert(host_klass != NULL || NULL == cp_patches,
1075 "cp_patches only found with host_klass");
1076
1077 return k;
1078 }
1079
1080 // Add a klass to the system from a stream (called by jni_DefineClass and
1081 // JVM_DefineClass).
1082 // Note: class_name can be NULL. In that case we do not know the name of
1083 // the class until we have parsed the stream.
1084
1085 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1086 Handle class_loader,
1087 Handle protection_domain,
1088 ClassFileStream* st,
1089 TRAPS) {
1090 #if INCLUDE_CDS
1091 ResourceMark rm(THREAD);
1092 if (DumpSharedSpaces && !class_loader.is_null() &&
1093 !ArgumentsExt::using_AppCDS() && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1094 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1095 // class, which is used by MethodHandles).
1096 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1097 }
1098 #endif
1099
1100 HandleMark hm(THREAD);
1101
1102 // Classloaders that support parallelism, e.g. bootstrap classloader,
1103 // or all classloaders with UnsyncloadClass do not acquire lock here
1104 bool DoObjectLock = true;
1105 if (is_parallelCapable(class_loader)) {
1106 DoObjectLock = false;
1107 }
1108
1109 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1110
1111 // Make sure we are synchronized on the class loader before we proceed
1112 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1113 check_loader_lock_contention(lockObject, THREAD);
1114 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1115
1116 assert(st != NULL, "invariant");
1117
1118 // Parse the stream and create a klass.
1119 // Note that we do this even though this klass might
1120 // already be present in the SystemDictionary, otherwise we would not
1121 // throw potential ClassFormatErrors.
1122 InstanceKlass* k = NULL;
1123
1124 #if INCLUDE_CDS
1125 if (!DumpSharedSpaces) {
1126 k = SystemDictionaryShared::lookup_from_stream(class_name,
1127 class_loader,
1128 protection_domain,
1129 st,
1130 CHECK_NULL);
1131 }
1132 #endif
1133
1134 if (k == NULL) {
1135 if (st->buffer() == NULL) {
1136 return NULL;
1137 }
1138 k = KlassFactory::create_from_stream(st,
1139 class_name,
1140 loader_data,
1141 protection_domain,
1142 NULL, // host_klass
1143 NULL, // cp_patches
1144 CHECK_NULL);
1145 }
1146
1147 assert(k != NULL, "no klass created");
1148 Symbol* h_name = k->name();
1149 assert(class_name == NULL || class_name == h_name, "name mismatch");
1150
1151 // Add class just loaded
1152 // If a class loader supports parallel classloading handle parallel define requests
1153 // find_or_define_instance_class may return a different InstanceKlass
1154 if (is_parallelCapable(class_loader)) {
1155 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1156 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1157 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1158 assert(defined_k != NULL, "Should have a klass if there's no exception");
1159 loader_data->add_to_deallocate_list(k);
1160 k = defined_k;
1161 }
1162 } else {
1163 define_instance_class(k, THREAD);
1164 }
1165
1166 // If defining the class throws an exception register 'k' for cleanup.
1167 if (HAS_PENDING_EXCEPTION) {
1168 assert(k != NULL, "Must have an instance klass here!");
1169 loader_data->add_to_deallocate_list(k);
1170 return NULL;
1171 }
1172
1173 // Make sure we have an entry in the SystemDictionary on success
1174 debug_only( {
1175 MutexLocker mu(SystemDictionary_lock, THREAD);
1176
1177 Klass* check = find_class(h_name, k->class_loader_data());
1178 assert(check == k, "should be present in the dictionary");
1179 } );
1180
1181 return k;
1182 }
1183
1184 #if INCLUDE_CDS
1185 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1186 int number_of_entries) {
1187 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1188 "bad shared dictionary size.");
1189 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1190 _shared_dictionary_size, t, number_of_entries);
1191 }
1192
1193
1194 // If there is a shared dictionary, then find the entry for the
1195 // given shared system class, if any.
1196
1197 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1198 if (shared_dictionary() != NULL) {
1199 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1200 int d_index = shared_dictionary()->hash_to_index(d_hash);
1201
1202 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1203 } else {
1204 return NULL;
1205 }
1206 }
1207
1208
1209 // Load a class from the shared spaces (found through the shared system
1210 // dictionary). Force the superclass and all interfaces to be loaded.
1211 // Update the class definition to include sibling classes and no
1212 // subclasses (yet). [Classes in the shared space are not part of the
1213 // object hierarchy until loaded.]
1214
1215 InstanceKlass* SystemDictionary::load_shared_class(
1216 Symbol* class_name, Handle class_loader, TRAPS) {
1217 InstanceKlass* ik = find_shared_class(class_name);
1218 // Make sure we only return the boot class for the NULL classloader.
1219 if (ik != NULL &&
1220 ik->is_shared_boot_class() && class_loader.is_null()) {
1221 Handle protection_domain;
1222 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1223 }
1224 return NULL;
1225 }
1226
1227 // Check if a shared class can be loaded by the specific classloader:
1228 //
1229 // NULL classloader:
1230 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1231 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1232 // be defined in an unnamed module.
1233 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1234 InstanceKlass* ik,
1235 Handle class_loader, TRAPS) {
1236 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1237 "Cannot use sharing if java.base is patched");
1238 ResourceMark rm;
1239 int path_index = ik->shared_classpath_index();
1240 ClassLoaderData* loader_data = class_loader_data(class_loader);
1241 if (path_index < 0) {
1242 // path_index < 0 indicates that the class is intended for a custom loader
1243 // and should not be loaded by boot/platform/app loaders
1244 if (loader_data->is_builtin_class_loader_data()) {
1245 return false;
1246 } else {
1247 return true;
1248 }
1249 }
1250 SharedClassPathEntry* ent =
1251 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1252 if (!Universe::is_module_initialized()) {
1253 assert(ent != NULL && ent->is_modules_image(),
1254 "Loading non-bootstrap classes before the module system is initialized");
1255 assert(class_loader.is_null(), "sanity");
1256 return true;
1257 }
1258 // Get the pkg_entry from the classloader
1259 TempNewSymbol pkg_name = NULL;
1260 PackageEntry* pkg_entry = NULL;
1261 ModuleEntry* mod_entry = NULL;
1262 const char* pkg_string = NULL;
1263 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1264 if (pkg_name != NULL) {
1265 pkg_string = pkg_name->as_C_string();
1266 if (loader_data != NULL) {
1267 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1268 }
1269 if (pkg_entry != NULL) {
1270 mod_entry = pkg_entry->module();
1271 }
1272 }
1273
1274 // If the archived class is from a module that has been patched at runtime,
1275 // the class cannot be loaded from the archive.
1276 if (mod_entry != NULL && mod_entry->is_patched()) {
1277 return false;
1278 }
1279
1280 if (class_loader.is_null()) {
1281 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1282 // The NULL classloader can load archived class originated from the
1283 // "modules" jimage and the -Xbootclasspath/a. For class from the
1284 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1285 // by the NULL classloader.
1286 if (mod_entry != NULL) {
1287 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1288 // ModuleEntry's location agrees with the archived class' origination.
1289 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1290 return true; // Module class from the "module" jimage
1291 }
1292 }
1293
1294 // If the archived class is not from the "module" jimage, the class can be
1295 // loaded by the NULL classloader if
1296 //
1297 // 1. the class is from the unamed package
1298 // 2. or, the class is not from a module defined in the NULL classloader
1299 // 3. or, the class is from an unamed module
1300 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1301 // the class is from the -Xbootclasspath/a
1302 if (pkg_string == NULL ||
1303 pkg_entry == NULL ||
1304 pkg_entry->in_unnamed_module()) {
1305 assert(mod_entry == NULL ||
1306 mod_entry == loader_data->unnamed_module(),
1307 "the unnamed module is not defined in the classloader");
1308 return true;
1309 }
1310 }
1311 return false;
1312 } else {
1313 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1314 ik, class_loader, pkg_string, pkg_name,
1315 pkg_entry, mod_entry, CHECK_(false));
1316 return res;
1317 }
1318 }
1319
1320 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1321 Handle class_loader,
1322 Handle protection_domain, TRAPS) {
1323
1324 if (ik != NULL) {
1325 Symbol* class_name = ik->name();
1326
1327 bool visible = is_shared_class_visible(
1328 class_name, ik, class_loader, CHECK_NULL);
1329 if (!visible) {
1330 return NULL;
1331 }
1332
1333 // Resolve the superclass and interfaces. They must be the same
1334 // as in dump time, because the layout of <ik> depends on
1335 // the specific layout of ik->super() and ik->local_interfaces().
1336 //
1337 // If unexpected superclass or interfaces are found, we cannot
1338 // load <ik> from the shared archive.
1339
1340 if (ik->super() != NULL) {
1341 Symbol* cn = ik->super()->name();
1342 Klass *s = resolve_super_or_fail(class_name, cn,
1343 class_loader, protection_domain, true, CHECK_NULL);
1344 if (s != ik->super()) {
1345 // The dynamically resolved super class is not the same as the one we used during dump time,
1346 // so we cannot use ik.
1347 return NULL;
1348 } else {
1349 assert(s->is_shared(), "must be");
1350 }
1351 }
1352
1353 Array<Klass*>* interfaces = ik->local_interfaces();
1354 int num_interfaces = interfaces->length();
1355 for (int index = 0; index < num_interfaces; index++) {
1356 Klass* k = interfaces->at(index);
1357 Symbol* name = k->name();
1358 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1359 if (k != i) {
1360 // The dynamically resolved interface class is not the same as the one we used during dump time,
1361 // so we cannot use ik.
1362 return NULL;
1363 } else {
1364 assert(i->is_shared(), "must be");
1365 }
1366 }
1367
1368 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1369 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1370 if (new_ik != NULL) {
1371 // The class is changed by CFLH. Return the new class. The shared class is
1372 // not used.
1373 return new_ik;
1374 }
1375
1376 // Adjust methods to recover missing data. They need addresses for
1377 // interpreter entry points and their default native method address
1378 // must be reset.
1379
1380 // Updating methods must be done under a lock so multiple
1381 // threads don't update these in parallel
1382 //
1383 // Shared classes are all currently loaded by either the bootstrap or
1384 // internal parallel class loaders, so this will never cause a deadlock
1385 // on a custom class loader lock.
1386
1387 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1388 {
1389 HandleMark hm(THREAD);
1390 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1391 check_loader_lock_contention(lockObject, THREAD);
1392 ObjectLocker ol(lockObject, THREAD, true);
1393 // prohibited package check assumes all classes loaded from archive call
1394 // restore_unshareable_info which calls ik->set_package()
1395 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1396 }
1397
1398 ik->print_class_load_logging(loader_data, NULL, NULL);
1399
1400 // For boot loader, ensure that GetSystemPackage knows that a class in this
1401 // package was loaded.
1402 if (class_loader.is_null()) {
1403 int path_index = ik->shared_classpath_index();
1404 ResourceMark rm;
1405 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1406 }
1407
1408 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1409 // Only dump the classes that can be stored into CDS archive
1410 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1411 ResourceMark rm(THREAD);
1412 classlist_file->print_cr("%s", ik->name()->as_C_string());
1413 classlist_file->flush();
1414 }
1415 }
1416
1417 // notify a class loaded from shared object
1418 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1419 }
1420
1421 ik->set_has_passed_fingerprint_check(false);
1422 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1423 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1424 uint64_t cds_fp = ik->get_stored_fingerprint();
1425 if (aot_fp != 0 && aot_fp == cds_fp) {
1426 // This class matches with a class saved in an AOT library
1427 ik->set_has_passed_fingerprint_check(true);
1428 } else {
1429 ResourceMark rm;
1430 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1431 }
1432 }
1433 return ik;
1434 }
1435
1436 void SystemDictionary::clear_invoke_method_table() {
1437 SymbolPropertyEntry* spe = NULL;
1438 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1439 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1440 while (p != NULL) {
1441 spe = p;
1442 p = p->next();
1443 _invoke_method_table->free_entry(spe);
1444 }
1445 }
1446 }
1447 #endif // INCLUDE_CDS
1448
1449 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1450
1451 if (class_loader.is_null()) {
1452 ResourceMark rm;
1453 PackageEntry* pkg_entry = NULL;
1454 bool search_only_bootloader_append = false;
1455 ClassLoaderData *loader_data = class_loader_data(class_loader);
1456
1457 // Find the package in the boot loader's package entry table.
1458 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1459 if (pkg_name != NULL) {
1460 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1461 }
1462
1463 // Prior to attempting to load the class, enforce the boot loader's
1464 // visibility boundaries.
1465 if (!Universe::is_module_initialized()) {
1466 // During bootstrapping, prior to module initialization, any
1467 // class attempting to be loaded must be checked against the
1468 // java.base packages in the boot loader's PackageEntryTable.
1469 // No class outside of java.base is allowed to be loaded during
1470 // this bootstrapping window.
1471 if (!DumpSharedSpaces) {
1472 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1473 // Class is either in the unnamed package or in
1474 // a named package within the unnamed module. Either
1475 // case is outside of java.base, do not attempt to
1476 // load the class post java.base definition. If
1477 // java.base has not been defined, let the class load
1478 // and its package will be checked later by
1479 // ModuleEntryTable::verify_javabase_packages.
1480 if (ModuleEntryTable::javabase_defined()) {
1481 return NULL;
1482 }
1483 } else {
1484 // Check that the class' package is defined within java.base.
1485 ModuleEntry* mod_entry = pkg_entry->module();
1486 Symbol* mod_entry_name = mod_entry->name();
1487 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1488 return NULL;
1489 }
1490 }
1491 }
1492 } else {
1493 // After the module system has been initialized, check if the class'
1494 // package is in a module defined to the boot loader.
1495 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1496 // Class is either in the unnamed package, in a named package
1497 // within a module not defined to the boot loader or in a
1498 // a named package within the unnamed module. In all cases,
1499 // limit visibility to search for the class only in the boot
1500 // loader's append path.
1501 search_only_bootloader_append = true;
1502 }
1503 }
1504
1505 // Prior to bootstrapping's module initialization, never load a class outside
1506 // of the boot loader's module path
1507 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1508 !search_only_bootloader_append,
1509 "Attempt to load a class outside of boot loader's module path");
1510
1511 // Search the shared system dictionary for classes preloaded into the
1512 // shared spaces.
1513 InstanceKlass* k = NULL;
1514 {
1515 #if INCLUDE_CDS
1516 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1517 k = load_shared_class(class_name, class_loader, THREAD);
1518 #endif
1519 }
1520
1521 if (k == NULL) {
1522 // Use VM class loader
1523 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1524 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1525 }
1526
1527 // find_or_define_instance_class may return a different InstanceKlass
1528 if (k != NULL) {
1529 InstanceKlass* defined_k =
1530 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1531 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1532 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1533 assert(defined_k != NULL, "Should have a klass if there's no exception");
1534 loader_data->add_to_deallocate_list(k);
1535 k = defined_k;
1536 } else if (HAS_PENDING_EXCEPTION) {
1537 loader_data->add_to_deallocate_list(k);
1538 return NULL;
1539 }
1540 }
1541 return k;
1542 } else {
1543 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1544 ResourceMark rm(THREAD);
1545
1546 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1547 JavaThread* jt = (JavaThread*) THREAD;
1548
1549 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1550 ClassLoader::perf_app_classload_selftime(),
1551 ClassLoader::perf_app_classload_count(),
1552 jt->get_thread_stat()->perf_recursion_counts_addr(),
1553 jt->get_thread_stat()->perf_timers_addr(),
1554 PerfClassTraceTime::CLASS_LOAD);
1555
1556 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1557 // Translate to external class name format, i.e., convert '/' chars to '.'
1558 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1559
1560 JavaValue result(T_OBJECT);
1561
1562 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1563
1564 // Call public unsynchronized loadClass(String) directly for all class loaders
1565 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1566 // acquire a class-name based lock rather than the class loader object lock.
1567 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1568 // so the call to loadClassInternal() was not required.
1569 //
1570 // UnsyncloadClass flag means both call loadClass(String) and do
1571 // not acquire the class loader lock even for class loaders that are
1572 // not parallelCapable. This was a risky transitional
1573 // flag for diagnostic purposes only. It is risky to call
1574 // custom class loaders without synchronization.
1575 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1576 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1577 // Do NOT assume this will be supported in future releases.
1578 //
1579 // Added MustCallLoadClassInternal in case we discover in the field
1580 // a customer that counts on this call
1581 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1582 JavaCalls::call_special(&result,
1583 class_loader,
1584 spec_klass,
1585 vmSymbols::loadClassInternal_name(),
1586 vmSymbols::string_class_signature(),
1587 string,
1588 CHECK_NULL);
1589 } else {
1590 JavaCalls::call_virtual(&result,
1591 class_loader,
1592 spec_klass,
1593 vmSymbols::loadClass_name(),
1594 vmSymbols::string_class_signature(),
1595 string,
1596 CHECK_NULL);
1597 }
1598
1599 assert(result.get_type() == T_OBJECT, "just checking");
1600 oop obj = (oop) result.get_jobject();
1601
1602 // Primitive classes return null since forName() can not be
1603 // used to obtain any of the Class objects representing primitives or void
1604 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1605 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1606 // For user defined Java class loaders, check that the name returned is
1607 // the same as that requested. This check is done for the bootstrap
1608 // loader when parsing the class file.
1609 if (class_name == k->name()) {
1610 return k;
1611 }
1612 }
1613 // Class is not found or has the wrong name, return NULL
1614 return NULL;
1615 }
1616 }
1617
1618 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1619
1620 HandleMark hm(THREAD);
1621 ClassLoaderData* loader_data = k->class_loader_data();
1622 Handle class_loader_h(THREAD, loader_data->class_loader());
1623
1624 // for bootstrap and other parallel classloaders don't acquire lock,
1625 // use placeholder token
1626 // If a parallelCapable class loader calls define_instance_class instead of
1627 // find_or_define_instance_class to get here, we have a timing
1628 // hole with systemDictionary updates and check_constraints
1629 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1630 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1631 compute_loader_lock_object(class_loader_h, THREAD)),
1632 "define called without lock");
1633 }
1634
1635 // Check class-loading constraints. Throw exception if violation is detected.
1636 // Grabs and releases SystemDictionary_lock
1637 // The check_constraints/find_class call and update_dictionary sequence
1638 // must be "atomic" for a specific class/classloader pair so we never
1639 // define two different instanceKlasses for that class/classloader pair.
1640 // Existing classloaders will call define_instance_class with the
1641 // classloader lock held
1642 // Parallel classloaders will call find_or_define_instance_class
1643 // which will require a token to perform the define class
1644 Symbol* name_h = k->name();
1645 Dictionary* dictionary = loader_data->dictionary();
1646 unsigned int d_hash = dictionary->compute_hash(name_h);
1647 int d_index = dictionary->hash_to_index(d_hash);
1648 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1649
1650 // Register class just loaded with class loader (placed in Vector)
1651 // Note we do this before updating the dictionary, as this can
1652 // fail with an OutOfMemoryError (if it does, we will *not* put this
1653 // class in the dictionary and will not update the class hierarchy).
1654 // JVMTI FollowReferences needs to find the classes this way.
1655 if (k->class_loader() != NULL) {
1656 methodHandle m(THREAD, Universe::loader_addClass_method());
1657 JavaValue result(T_VOID);
1658 JavaCallArguments args(class_loader_h);
1659 args.push_oop(Handle(THREAD, k->java_mirror()));
1660 JavaCalls::call(&result, m, &args, CHECK);
1661 }
1662
1663 // Add the new class. We need recompile lock during update of CHA.
1664 {
1665 unsigned int p_hash = placeholders()->compute_hash(name_h);
1666 int p_index = placeholders()->hash_to_index(p_hash);
1667
1668 MutexLocker mu_r(Compile_lock, THREAD);
1669
1670 // Add to class hierarchy, initialize vtables, and do possible
1671 // deoptimizations.
1672 add_to_hierarchy(k, CHECK); // No exception, but can block
1673
1674 // Add to systemDictionary - so other classes can see it.
1675 // Grabs and releases SystemDictionary_lock
1676 update_dictionary(d_index, d_hash, p_index, p_hash,
1677 k, class_loader_h, THREAD);
1678 }
1679 k->eager_initialize(THREAD);
1680
1681 // notify jvmti
1682 if (JvmtiExport::should_post_class_load()) {
1683 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1684 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1685
1686 }
1687 class_define_event(k, loader_data);
1688 }
1689
1690 // Support parallel classloading
1691 // All parallel class loaders, including bootstrap classloader
1692 // lock a placeholder entry for this class/class_loader pair
1693 // to allow parallel defines of different classes for this class loader
1694 // With AllowParallelDefine flag==true, in case they do not synchronize around
1695 // FindLoadedClass/DefineClass, calls, we check for parallel
1696 // loading for them, wait if a defineClass is in progress
1697 // and return the initial requestor's results
1698 // This flag does not apply to the bootstrap classloader.
1699 // With AllowParallelDefine flag==false, call through to define_instance_class
1700 // which will throw LinkageError: duplicate class definition.
1701 // False is the requested default.
1702 // For better performance, the class loaders should synchronize
1703 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1704 // potentially waste time reading and parsing the bytestream.
1705 // Note: VM callers should ensure consistency of k/class_name,class_loader
1706 // Be careful when modifying this code: once you have run
1707 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1708 // you need to find_and_remove it before returning.
1709 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1710 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1711 InstanceKlass* k, TRAPS) {
1712
1713 Symbol* name_h = k->name(); // passed in class_name may be null
1714 ClassLoaderData* loader_data = class_loader_data(class_loader);
1715 Dictionary* dictionary = loader_data->dictionary();
1716
1717 unsigned int d_hash = dictionary->compute_hash(name_h);
1718 int d_index = dictionary->hash_to_index(d_hash);
1719
1720 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1721 unsigned int p_hash = placeholders()->compute_hash(name_h);
1722 int p_index = placeholders()->hash_to_index(p_hash);
1723 PlaceholderEntry* probe;
1724
1725 {
1726 MutexLocker mu(SystemDictionary_lock, THREAD);
1727 // First check if class already defined
1728 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1729 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1730 if (check != NULL) {
1731 return check;
1732 }
1733 }
1734
1735 // Acquire define token for this class/classloader
1736 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1737 // Wait if another thread defining in parallel
1738 // All threads wait - even those that will throw duplicate class: otherwise
1739 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1740 // if other thread has not finished updating dictionary
1741 while (probe->definer() != NULL) {
1742 SystemDictionary_lock->wait();
1743 }
1744 // Only special cases allow parallel defines and can use other thread's results
1745 // Other cases fall through, and may run into duplicate defines
1746 // caught by finding an entry in the SystemDictionary
1747 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1748 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1749 SystemDictionary_lock->notify_all();
1750 #ifdef ASSERT
1751 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1752 assert(check != NULL, "definer missed recording success");
1753 #endif
1754 return probe->instance_klass();
1755 } else {
1756 // This thread will define the class (even if earlier thread tried and had an error)
1757 probe->set_definer(THREAD);
1758 }
1759 }
1760
1761 define_instance_class(k, THREAD);
1762
1763 Handle linkage_exception = Handle(); // null handle
1764
1765 // definer must notify any waiting threads
1766 {
1767 MutexLocker mu(SystemDictionary_lock, THREAD);
1768 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1769 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1770 if (probe != NULL) {
1771 if (HAS_PENDING_EXCEPTION) {
1772 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1773 CLEAR_PENDING_EXCEPTION;
1774 } else {
1775 probe->set_instance_klass(k);
1776 }
1777 probe->set_definer(NULL);
1778 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1779 SystemDictionary_lock->notify_all();
1780 }
1781 }
1782
1783 // Can't throw exception while holding lock due to rank ordering
1784 if (linkage_exception() != NULL) {
1785 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1786 }
1787
1788 return k;
1789 }
1790
1791 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1792 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1793 if (class_loader.is_null()) {
1794 return Handle(THREAD, _system_loader_lock_obj);
1795 } else {
1796 return class_loader;
1797 }
1798 }
1799
1800 // This method is added to check how often we have to wait to grab loader
1801 // lock. The results are being recorded in the performance counters defined in
1802 // ClassLoader::_sync_systemLoaderLockContentionRate and
1803 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1804 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1805 if (!UsePerfData) {
1806 return;
1807 }
1808
1809 assert(!loader_lock.is_null(), "NULL lock object");
1810
1811 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1812 == ObjectSynchronizer::owner_other) {
1813 // contention will likely happen, so increment the corresponding
1814 // contention counter.
1815 if (loader_lock() == _system_loader_lock_obj) {
1816 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1817 } else {
1818 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1819 }
1820 }
1821 }
1822
1823 // ----------------------------------------------------------------------------
1824 // Lookup
1825
1826 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1827 Symbol* class_name,
1828 Dictionary* dictionary) {
1829 assert_locked_or_safepoint(SystemDictionary_lock);
1830 return dictionary->find_class(index, hash, class_name);
1831 }
1832
1833
1834 // Basic find on classes in the midst of being loaded
1835 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1836 ClassLoaderData* loader_data) {
1837 assert_locked_or_safepoint(SystemDictionary_lock);
1838 unsigned int p_hash = placeholders()->compute_hash(class_name);
1839 int p_index = placeholders()->hash_to_index(p_hash);
1840 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1841 }
1842
1843
1844 // Used for assertions and verification only
1845 // Precalculating the hash and index is an optimization because there are many lookups
1846 // before adding the class.
1847 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1848 assert_locked_or_safepoint(SystemDictionary_lock);
1849 #ifndef ASSERT
1850 guarantee(VerifyBeforeGC ||
1851 VerifyDuringGC ||
1852 VerifyBeforeExit ||
1853 VerifyDuringStartup ||
1854 VerifyAfterGC, "too expensive");
1855 #endif
1856
1857 Dictionary* dictionary = loader_data->dictionary();
1858 unsigned int d_hash = dictionary->compute_hash(class_name);
1859 int d_index = dictionary->hash_to_index(d_hash);
1860 return find_class(d_index, d_hash, class_name, dictionary);
1861 }
1862
1863
1864 // ----------------------------------------------------------------------------
1865 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1866 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1867 // before a new class is used.
1868
1869 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1870 assert(k != NULL, "just checking");
1871 assert_locked_or_safepoint(Compile_lock);
1872
1873 // Link into hierachy. Make sure the vtables are initialized before linking into
1874 k->append_to_sibling_list(); // add to superklass/sibling list
1875 k->process_interfaces(THREAD); // handle all "implements" declarations
1876 k->set_init_state(InstanceKlass::loaded);
1877 // Now flush all code that depended on old class hierarchy.
1878 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1879 // Also, first reinitialize vtable because it may have gotten out of synch
1880 // while the new class wasn't connected to the class hierarchy.
1881 CodeCache::flush_dependents_on(k);
1882 }
1883
1884 // ----------------------------------------------------------------------------
1885 // GC support
1886
1887 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1888 roots_oops_do(blk, NULL);
1889 }
1890
1891
1892 #ifdef ASSERT
1893 class VerifySDReachableAndLiveClosure : public OopClosure {
1894 private:
1895 BoolObjectClosure* _is_alive;
1896
1897 template <class T> void do_oop_work(T* p) {
1898 oop obj = oopDesc::load_decode_heap_oop(p);
1899 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1900 }
1901
1902 public:
1903 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1904
1905 virtual void do_oop(oop* p) { do_oop_work(p); }
1906 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1907 };
1908 #endif
1909
1910 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1911 // Note: anonymous classes are not in the SD.
1912 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1913 GCTimer* gc_timer,
1914 bool do_cleaning) {
1915
1916
1917 bool unloading_occurred;
1918 {
1919 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1920
1921 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1922 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1923 do_cleaning);
1924 }
1925
1926 if (unloading_occurred) {
1927 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1928 constraints()->purge_loader_constraints();
1929 resolution_errors()->purge_resolution_errors();
1930 }
1931
1932 {
1933 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1934 // Oops referenced by the protection domain cache table may get unreachable independently
1935 // of the class loader (eg. cached protection domain oops). So we need to
1936 // explicitly unlink them here.
1937 _pd_cache_table->unlink(is_alive);
1938
1939 #ifdef ASSERT
1940 VerifySDReachableAndLiveClosure cl(is_alive);
1941 _pd_cache_table->oops_do(&cl);
1942 #endif
1943 }
1944
1945 if (do_cleaning) {
1946 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1947 ResolvedMethodTable::unlink(is_alive);
1948 }
1949
1950 return unloading_occurred;
1951 }
1952
1953 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1954 strong->do_oop(&_java_system_loader);
1955 strong->do_oop(&_java_platform_loader);
1956 strong->do_oop(&_system_loader_lock_obj);
1957 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1958
1959 // Do strong roots marking if the closures are the same.
1960 if (strong == weak || !ClassUnloading) {
1961 // Only the protection domain oops contain references into the heap. Iterate
1962 // over all of them.
1963 _pd_cache_table->oops_do(strong);
1964 } else {
1965 if (weak != NULL) {
1966 _pd_cache_table->oops_do(weak);
1967 }
1968 }
1969
1970 // Visit extra methods
1971 invoke_method_table()->oops_do(strong);
1972
1973 if (weak != NULL) {
1974 ResolvedMethodTable::oops_do(weak);
1975 }
1976 }
1977
1978 void SystemDictionary::oops_do(OopClosure* f) {
1979 f->do_oop(&_java_system_loader);
1980 f->do_oop(&_java_platform_loader);
1981 f->do_oop(&_system_loader_lock_obj);
1982 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1983
1984 // Only the protection domain oops contain references into the heap. Iterate
1985 // over all of them.
1986 _pd_cache_table->oops_do(f);
1987
1988 // Visit extra methods
1989 invoke_method_table()->oops_do(f);
1990
1991 ResolvedMethodTable::oops_do(f);
1992 }
1993
1994 // CDS: scan and relocate all classes in the system dictionary.
1995 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1996 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1997 }
1998
1999 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
2000 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
2001 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
2002 it->push(well_known_klass_addr((WKID)id));
2003 }
2004 }
2005
2006 void SystemDictionary::methods_do(void f(Method*)) {
2007 // Walk methods in loaded classes
2008 ClassLoaderDataGraph::methods_do(f);
2009 // Walk method handle intrinsics
2010 invoke_method_table()->methods_do(f);
2011 }
2012
2013 class RemoveClassesClosure : public CLDClosure {
2014 public:
2015 void do_cld(ClassLoaderData* cld) {
2016 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2017 cld->dictionary()->remove_classes_in_error_state();
2018 }
2019 }
2020 };
2021
2022 void SystemDictionary::remove_classes_in_error_state() {
2023 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
2024 RemoveClassesClosure rcc;
2025 ClassLoaderDataGraph::cld_do(&rcc);
2026 }
2027
2028 // ----------------------------------------------------------------------------
2029 // Lazily load klasses
2030
2031 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2032 // if multiple threads calling this function, only one thread will load
2033 // the class. The other threads will find the loaded version once the
2034 // class is loaded.
2035 Klass* aos = _abstract_ownable_synchronizer_klass;
2036 if (aos == NULL) {
2037 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2038 // Force a fence to prevent any read before the write completes
2039 OrderAccess::fence();
2040 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2041 }
2042 }
2043
2044 // ----------------------------------------------------------------------------
2045 // Initialization
2046
2047 void SystemDictionary::initialize(TRAPS) {
2048 // Allocate arrays
2049 _placeholders = new PlaceholderTable(_placeholder_table_size);
2050 _number_of_modifications = 0;
2051 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2052 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2053 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2054 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2055
2056 // Allocate private object used as system class loader lock
2057 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2058 // Initialize basic classes
2059 initialize_preloaded_classes(CHECK);
2060 }
2061
2062 // Compact table of directions on the initialization of klasses:
2063 static const short wk_init_info[] = {
2064 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2065 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2066 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2067 | (int)SystemDictionary::option ),
2068 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2069 #undef WK_KLASS_INIT_INFO
2070 0
2071 };
2072
2073 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2074 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2075 int info = wk_init_info[id - FIRST_WKID];
2076 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2077 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2078 InstanceKlass** klassp = &_well_known_klasses[id];
2079
2080 bool must_load;
2081 #if INCLUDE_JVMCI
2082 if (EnableJVMCI) {
2083 // If JVMCI is enabled we require its classes to be found.
2084 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2085 } else
2086 #endif
2087 {
2088 must_load = (init_opt < SystemDictionary::Opt);
2089 }
2090
2091 if ((*klassp) == NULL) {
2092 Klass* k;
2093 if (must_load) {
2094 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2095 } else {
2096 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2097 }
2098 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2099 }
2100 return ((*klassp) != NULL);
2101 }
2102
2103 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2104 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2105 for (int id = (int)start_id; id < (int)limit_id; id++) {
2106 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2107 int info = wk_init_info[id - FIRST_WKID];
2108 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2109 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2110
2111 initialize_wk_klass((WKID)id, opt, CHECK);
2112 }
2113
2114 // move the starting value forward to the limit:
2115 start_id = limit_id;
2116 }
2117
2118 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2119 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2120
2121 // Create the ModuleEntry for java.base. This call needs to be done here,
2122 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2123 ClassLoader::classLoader_init2(CHECK);
2124
2125 // Preload commonly used klasses
2126 WKID scan = FIRST_WKID;
2127 // first do Object, then String, Class
2128 #if INCLUDE_CDS
2129 if (UseSharedSpaces) {
2130 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2131 // Initialize the constant pool for the Object_class
2132 Object_klass()->constants()->restore_unshareable_info(CHECK);
2133 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2134 } else
2135 #endif
2136 {
2137 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2138 }
2139
2140 // Calculate offsets for String and Class classes since they are loaded and
2141 // can be used after this point.
2142 java_lang_String::compute_offsets();
2143 java_lang_Class::compute_offsets();
2144
2145 // Fixup mirrors for classes loaded before java.lang.Class.
2146 // These calls iterate over the objects currently in the perm gen
2147 // so calling them at this point is matters (not before when there
2148 // are fewer objects and not later after there are more objects
2149 // in the perm gen.
2150 Universe::initialize_basic_type_mirrors(CHECK);
2151 Universe::fixup_mirrors(CHECK);
2152
2153 // do a bunch more:
2154 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2155
2156 // Preload ref klasses and set reference types
2157 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2158 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2159
2160 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2161 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2162 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2163 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2164 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2165
2166 // JSR 292 classes
2167 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2168 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2169 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2170 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2171 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2172
2173 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2174 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2175 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2176 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2177 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2178 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2179 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2180 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2181 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2182 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2183
2184 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2185 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2186 _has_loadClassInternal = (method != NULL);
2187 }
2188 { // Compute whether we should use checkPackageAccess or NOT
2189 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2190 _has_checkPackageAccess = (method != NULL);
2191 }
2192 }
2193
2194 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2195 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2196 BasicType SystemDictionary::box_klass_type(Klass* k) {
2197 assert(k != NULL, "");
2198 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2199 if (_box_klasses[i] == k)
2200 return (BasicType)i;
2201 }
2202 return T_OBJECT;
2203 }
2204
2205 // Constraints on class loaders. The details of the algorithm can be
2206 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2207 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2208 // that the dictionary needs to maintain a set of contraints that
2209 // must be satisfied by all classes in the dictionary.
2210 // if defining is true, then LinkageError if already in dictionary
2211 // if initiating loader, then ok if InstanceKlass matches existing entry
2212
2213 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2214 InstanceKlass* k,
2215 Handle class_loader, bool defining,
2216 TRAPS) {
2217 const char *linkage_error1 = NULL;
2218 const char *linkage_error2 = NULL;
2219 {
2220 Symbol* name = k->name();
2221 ClassLoaderData *loader_data = class_loader_data(class_loader);
2222
2223 MutexLocker mu(SystemDictionary_lock, THREAD);
2224
2225 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2226 if (check != NULL) {
2227 // if different InstanceKlass - duplicate class definition,
2228 // else - ok, class loaded by a different thread in parallel,
2229 // we should only have found it if it was done loading and ok to use
2230 // dictionary only holds instance classes, placeholders
2231 // also holds array classes
2232
2233 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2234 if ((defining == true) || (k != check)) {
2235 linkage_error1 = "loader (instance of ";
2236 linkage_error2 = "): attempted duplicate class definition for name: \"";
2237 } else {
2238 return;
2239 }
2240 }
2241
2242 #ifdef ASSERT
2243 Symbol* ph_check = find_placeholder(name, loader_data);
2244 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2245 #endif
2246
2247 if (linkage_error1 == NULL) {
2248 if (constraints()->check_or_update(k, class_loader, name) == false) {
2249 linkage_error1 = "loader constraint violation: loader (instance of ";
2250 linkage_error2 = ") previously initiated loading for a different type with name \"";
2251 }
2252 }
2253 }
2254
2255 // Throw error now if needed (cannot throw while holding
2256 // SystemDictionary_lock because of rank ordering)
2257
2258 if (linkage_error1) {
2259 ResourceMark rm(THREAD);
2260 const char* class_loader_name = loader_name(class_loader());
2261 char* type_name = k->name()->as_C_string();
2262 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2263 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2264 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2265 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2266 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2267 }
2268 }
2269
2270
2271 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2272 // have been called.
2273 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2274 int p_index, unsigned int p_hash,
2275 InstanceKlass* k,
2276 Handle class_loader,
2277 TRAPS) {
2278 // Compile_lock prevents systemDictionary updates during compilations
2279 assert_locked_or_safepoint(Compile_lock);
2280 Symbol* name = k->name();
2281 ClassLoaderData *loader_data = class_loader_data(class_loader);
2282
2283 {
2284 MutexLocker mu1(SystemDictionary_lock, THREAD);
2285
2286 // See whether biased locking is enabled and if so set it for this
2287 // klass.
2288 // Note that this must be done past the last potential blocking
2289 // point / safepoint. We enable biased locking lazily using a
2290 // VM_Operation to iterate the SystemDictionary and installing the
2291 // biasable mark word into each InstanceKlass's prototype header.
2292 // To avoid race conditions where we accidentally miss enabling the
2293 // optimization for one class in the process of being added to the
2294 // dictionary, we must not safepoint after the test of
2295 // BiasedLocking::enabled().
2296 if (UseBiasedLocking && BiasedLocking::enabled()) {
2297 // Set biased locking bit for all loaded classes; it will be
2298 // cleared if revocation occurs too often for this type
2299 // NOTE that we must only do this when the class is initally
2300 // defined, not each time it is referenced from a new class loader
2301 if (k->class_loader() == class_loader()) {
2302 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2303 }
2304 }
2305
2306 // Make a new dictionary entry.
2307 Dictionary* dictionary = loader_data->dictionary();
2308 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2309 if (sd_check == NULL) {
2310 dictionary->add_klass(d_index, d_hash, name, k);
2311 notice_modification();
2312 }
2313 #ifdef ASSERT
2314 sd_check = find_class(d_index, d_hash, name, dictionary);
2315 assert (sd_check != NULL, "should have entry in dictionary");
2316 // Note: there may be a placeholder entry: for circularity testing
2317 // or for parallel defines
2318 #endif
2319 SystemDictionary_lock->notify_all();
2320 }
2321 }
2322
2323
2324 // Try to find a class name using the loader constraints. The
2325 // loader constraints might know about a class that isn't fully loaded
2326 // yet and these will be ignored.
2327 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2328 Symbol* class_name, Handle class_loader, TRAPS) {
2329
2330 // First see if it has been loaded directly.
2331 // Force the protection domain to be null. (This removes protection checks.)
2332 Handle no_protection_domain;
2333 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2334 no_protection_domain, CHECK_NULL);
2335 if (klass != NULL)
2336 return klass;
2337
2338 // Now look to see if it has been loaded elsewhere, and is subject to
2339 // a loader constraint that would require this loader to return the
2340 // klass that is already loaded.
2341 if (FieldType::is_array(class_name)) {
2342 // For array classes, their Klass*s are not kept in the
2343 // constraint table. The element Klass*s are.
2344 FieldArrayInfo fd;
2345 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2346 if (t != T_OBJECT) {
2347 klass = Universe::typeArrayKlassObj(t);
2348 } else {
2349 MutexLocker mu(SystemDictionary_lock, THREAD);
2350 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2351 }
2352 // If element class already loaded, allocate array klass
2353 if (klass != NULL) {
2354 klass = klass->array_klass_or_null(fd.dimension());
2355 }
2356 } else {
2357 MutexLocker mu(SystemDictionary_lock, THREAD);
2358 // Non-array classes are easy: simply check the constraint table.
2359 klass = constraints()->find_constrained_klass(class_name, class_loader);
2360 }
2361
2362 return klass;
2363 }
2364
2365
2366 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2367 Handle class_loader1,
2368 Handle class_loader2,
2369 Thread* THREAD) {
2370 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2371 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2372
2373 Symbol* constraint_name = NULL;
2374 if (!FieldType::is_array(class_name)) {
2375 constraint_name = class_name;
2376 } else {
2377 // For array classes, their Klass*s are not kept in the
2378 // constraint table. The element classes are.
2379 FieldArrayInfo fd;
2380 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2381 // primitive types always pass
2382 if (t != T_OBJECT) {
2383 return true;
2384 } else {
2385 constraint_name = fd.object_key();
2386 }
2387 }
2388
2389 Dictionary* dictionary1 = loader_data1->dictionary();
2390 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2391 int d_index1 = dictionary1->hash_to_index(d_hash1);
2392
2393 Dictionary* dictionary2 = loader_data2->dictionary();
2394 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2395 int d_index2 = dictionary2->hash_to_index(d_hash2);
2396
2397 {
2398 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2399 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2400 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2401 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2402 klass2, class_loader2);
2403 }
2404 }
2405
2406 // Add entry to resolution error table to record the error when the first
2407 // attempt to resolve a reference to a class has failed.
2408 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2409 Symbol* error, Symbol* message) {
2410 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2411 int index = resolution_errors()->hash_to_index(hash);
2412 {
2413 MutexLocker ml(SystemDictionary_lock, Thread::current());
2414 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2415 }
2416 }
2417
2418 // Delete a resolution error for RedefineClasses for a constant pool is going away
2419 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2420 resolution_errors()->delete_entry(pool);
2421 }
2422
2423 // Lookup resolution error table. Returns error if found, otherwise NULL.
2424 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2425 Symbol** message) {
2426 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2427 int index = resolution_errors()->hash_to_index(hash);
2428 {
2429 MutexLocker ml(SystemDictionary_lock, Thread::current());
2430 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2431 if (entry != NULL) {
2432 *message = entry->message();
2433 return entry->error();
2434 } else {
2435 return NULL;
2436 }
2437 }
2438 }
2439
2440
2441 // Signature constraints ensure that callers and callees agree about
2442 // the meaning of type names in their signatures. This routine is the
2443 // intake for constraints. It collects them from several places:
2444 //
2445 // * LinkResolver::resolve_method (if check_access is true) requires
2446 // that the resolving class (the caller) and the defining class of
2447 // the resolved method (the callee) agree on each type in the
2448 // method's signature.
2449 //
2450 // * LinkResolver::resolve_interface_method performs exactly the same
2451 // checks.
2452 //
2453 // * LinkResolver::resolve_field requires that the constant pool
2454 // attempting to link to a field agree with the field's defining
2455 // class about the type of the field signature.
2456 //
2457 // * klassVtable::initialize_vtable requires that, when a class
2458 // overrides a vtable entry allocated by a superclass, that the
2459 // overriding method (i.e., the callee) agree with the superclass
2460 // on each type in the method's signature.
2461 //
2462 // * klassItable::initialize_itable requires that, when a class fills
2463 // in its itables, for each non-abstract method installed in an
2464 // itable, the method (i.e., the callee) agree with the interface
2465 // on each type in the method's signature.
2466 //
2467 // All those methods have a boolean (check_access, checkconstraints)
2468 // which turns off the checks. This is used from specialized contexts
2469 // such as bootstrapping, dumping, and debugging.
2470 //
2471 // No direct constraint is placed between the class and its
2472 // supertypes. Constraints are only placed along linked relations
2473 // between callers and callees. When a method overrides or implements
2474 // an abstract method in a supertype (superclass or interface), the
2475 // constraints are placed as if the supertype were the caller to the
2476 // overriding method. (This works well, since callers to the
2477 // supertype have already established agreement between themselves and
2478 // the supertype.) As a result of all this, a class can disagree with
2479 // its supertype about the meaning of a type name, as long as that
2480 // class neither calls a relevant method of the supertype, nor is
2481 // called (perhaps via an override) from the supertype.
2482 //
2483 //
2484 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2485 //
2486 // Make sure all class components (including arrays) in the given
2487 // signature will be resolved to the same class in both loaders.
2488 // Returns the name of the type that failed a loader constraint check, or
2489 // NULL if no constraint failed. No exception except OOME is thrown.
2490 // Arrays are not added to the loader constraint table, their elements are.
2491 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2492 Handle loader1, Handle loader2,
2493 bool is_method, TRAPS) {
2494 // Nothing to do if loaders are the same.
2495 if (loader1() == loader2()) {
2496 return NULL;
2497 }
2498
2499 SignatureStream sig_strm(signature, is_method);
2500 while (!sig_strm.is_done()) {
2501 if (sig_strm.is_object()) {
2502 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2503 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2504 return sig;
2505 }
2506 }
2507 sig_strm.next();
2508 }
2509 return NULL;
2510 }
2511
2512
2513 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2514 Symbol* signature,
2515 TRAPS) {
2516 methodHandle empty;
2517 assert(MethodHandles::is_signature_polymorphic(iid) &&
2518 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2519 iid != vmIntrinsics::_invokeGeneric,
2520 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2521
2522 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2523 int index = invoke_method_table()->hash_to_index(hash);
2524 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2525 methodHandle m;
2526 if (spe == NULL || spe->method() == NULL) {
2527 spe = NULL;
2528 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2529 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2530 if (!Arguments::is_interpreter_only()) {
2531 // Generate a compiled form of the MH intrinsic.
2532 AdapterHandlerLibrary::create_native_wrapper(m);
2533 // Check if have the compiled code.
2534 if (!m->has_compiled_code()) {
2535 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2536 "Out of space in CodeCache for method handle intrinsic", empty);
2537 }
2538 }
2539 // Now grab the lock. We might have to throw away the new method,
2540 // if a racing thread has managed to install one at the same time.
2541 {
2542 MutexLocker ml(SystemDictionary_lock, THREAD);
2543 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2544 if (spe == NULL)
2545 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2546 if (spe->method() == NULL)
2547 spe->set_method(m());
2548 }
2549 }
2550
2551 assert(spe != NULL && spe->method() != NULL, "");
2552 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2553 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2554 "MH intrinsic invariant");
2555 return spe->method();
2556 }
2557
2558 // Helper for unpacking the return value from linkMethod and linkCallSite.
2559 static methodHandle unpack_method_and_appendix(Handle mname,
2560 Klass* accessing_klass,
2561 objArrayHandle appendix_box,
2562 Handle* appendix_result,
2563 TRAPS) {
2564 methodHandle empty;
2565 if (mname.not_null()) {
2566 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2567 if (m != NULL) {
2568 oop appendix = appendix_box->obj_at(0);
2569 if (TraceMethodHandles) {
2570 #ifndef PRODUCT
2571 ttyLocker ttyl;
2572 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2573 m->print();
2574 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2575 tty->cr();
2576 #endif //PRODUCT
2577 }
2578 (*appendix_result) = Handle(THREAD, appendix);
2579 // the target is stored in the cpCache and if a reference to this
2580 // MethodName is dropped we need a way to make sure the
2581 // class_loader containing this method is kept alive.
2582 // FIXME: the appendix might also preserve this dependency.
2583 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2584 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2585 return methodHandle(THREAD, m);
2586 }
2587 }
2588 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2589 return empty;
2590 }
2591
2592 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2593 Symbol* name,
2594 Symbol* signature,
2595 Klass* accessing_klass,
2596 Handle *appendix_result,
2597 Handle *method_type_result,
2598 TRAPS) {
2599 methodHandle empty;
2600 assert(THREAD->can_call_java() ,"");
2601 Handle method_type =
2602 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2603
2604 int ref_kind = JVM_REF_invokeVirtual;
2605 oop name_oop = StringTable::intern(name, CHECK_(empty));
2606 Handle name_str (THREAD, name_oop);
2607 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2608 assert(appendix_box->obj_at(0) == NULL, "");
2609
2610 // This should not happen. JDK code should take care of that.
2611 if (accessing_klass == NULL || method_type.is_null()) {
2612 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2613 }
2614
2615 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2616 JavaCallArguments args;
2617 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2618 args.push_int(ref_kind);
2619 args.push_oop(Handle(THREAD, klass->java_mirror()));
2620 args.push_oop(name_str);
2621 args.push_oop(method_type);
2622 args.push_oop(appendix_box);
2623 JavaValue result(T_OBJECT);
2624 JavaCalls::call_static(&result,
2625 SystemDictionary::MethodHandleNatives_klass(),
2626 vmSymbols::linkMethod_name(),
2627 vmSymbols::linkMethod_signature(),
2628 &args, CHECK_(empty));
2629 Handle mname(THREAD, (oop) result.get_jobject());
2630 (*method_type_result) = method_type;
2631 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2632 }
2633
2634 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2635 // We must ensure that all class loaders everywhere will reach this class, for any client.
2636 // This is a safe bet for public classes in java.lang, such as Object and String.
2637 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2638 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2639 static bool is_always_visible_class(oop mirror) {
2640 Klass* klass = java_lang_Class::as_Klass(mirror);
2641 if (klass->is_objArray_klass()) {
2642 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2643 }
2644 if (klass->is_typeArray_klass()) {
2645 return true; // primitive array
2646 }
2647 assert(klass->is_instance_klass(), "%s", klass->external_name());
2648 return klass->is_public() &&
2649 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2650 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2651 }
2652
2653 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2654 // signature, as interpreted relative to the given class loader.
2655 // Because of class loader constraints, all method handle usage must be
2656 // consistent with this loader.
2657 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2658 Klass* accessing_klass,
2659 TRAPS) {
2660 Handle empty;
2661 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2662 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2663 int index = invoke_method_table()->hash_to_index(hash);
2664 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2665 if (spe != NULL && spe->method_type() != NULL) {
2666 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2667 return Handle(THREAD, spe->method_type());
2668 } else if (!THREAD->can_call_java()) {
2669 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2670 return Handle(); // do not attempt from within compiler, unless it was cached
2671 }
2672
2673 Handle class_loader, protection_domain;
2674 if (accessing_klass != NULL) {
2675 class_loader = Handle(THREAD, accessing_klass->class_loader());
2676 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2677 }
2678 bool can_be_cached = true;
2679 int npts = ArgumentCount(signature).size();
2680 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2681 int arg = 0;
2682 Handle rt; // the return type from the signature
2683 ResourceMark rm(THREAD);
2684 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2685 oop mirror = NULL;
2686 if (can_be_cached) {
2687 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2688 mirror = ss.as_java_mirror(Handle(), Handle(),
2689 SignatureStream::ReturnNull, CHECK_(empty));
2690 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2691 // Fall back to accessing_klass context.
2692 can_be_cached = false;
2693 }
2694 }
2695 if (!can_be_cached) {
2696 // Resolve, throwing a real error if it doesn't work.
2697 mirror = ss.as_java_mirror(class_loader, protection_domain,
2698 SignatureStream::NCDFError, CHECK_(empty));
2699 }
2700 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2701 if (ss.at_return_type())
2702 rt = Handle(THREAD, mirror);
2703 else
2704 pts->obj_at_put(arg++, mirror);
2705
2706 // Check accessibility.
2707 if (ss.is_object() && accessing_klass != NULL) {
2708 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2709 mirror = NULL; // safety
2710 // Emulate ConstantPool::verify_constant_pool_resolve.
2711 if (sel_klass->is_objArray_klass())
2712 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2713 if (sel_klass->is_instance_klass()) {
2714 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2715 }
2716 }
2717 }
2718 assert(arg == npts, "");
2719
2720 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2721 JavaCallArguments args(Handle(THREAD, rt()));
2722 args.push_oop(pts);
2723 JavaValue result(T_OBJECT);
2724 JavaCalls::call_static(&result,
2725 SystemDictionary::MethodHandleNatives_klass(),
2726 vmSymbols::findMethodHandleType_name(),
2727 vmSymbols::findMethodHandleType_signature(),
2728 &args, CHECK_(empty));
2729 Handle method_type(THREAD, (oop) result.get_jobject());
2730
2731 if (can_be_cached) {
2732 // We can cache this MethodType inside the JVM.
2733 MutexLocker ml(SystemDictionary_lock, THREAD);
2734 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2735 if (spe == NULL)
2736 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2737 if (spe->method_type() == NULL) {
2738 spe->set_method_type(method_type());
2739 }
2740 }
2741
2742 // report back to the caller with the MethodType
2743 return method_type;
2744 }
2745
2746 // Ask Java code to find or construct a method handle constant.
2747 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2748 int ref_kind, //e.g., JVM_REF_invokeVirtual
2749 Klass* callee,
2750 Symbol* name_sym,
2751 Symbol* signature,
2752 TRAPS) {
2753 Handle empty;
2754 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2755 Handle type;
2756 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2757 type = find_method_handle_type(signature, caller, CHECK_(empty));
2758 } else if (caller == NULL) {
2759 // This should not happen. JDK code should take care of that.
2760 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2761 } else {
2762 ResourceMark rm(THREAD);
2763 SignatureStream ss(signature, false);
2764 if (!ss.is_done()) {
2765 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2766 Handle(THREAD, caller->protection_domain()),
2767 SignatureStream::NCDFError, CHECK_(empty));
2768 type = Handle(THREAD, mirror);
2769 ss.next();
2770 if (!ss.is_done()) type = Handle(); // error!
2771 }
2772 }
2773 if (type.is_null()) {
2774 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2775 }
2776
2777 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2778 JavaCallArguments args;
2779 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2780 args.push_int(ref_kind);
2781 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2782 args.push_oop(name);
2783 args.push_oop(type);
2784 JavaValue result(T_OBJECT);
2785 JavaCalls::call_static(&result,
2786 SystemDictionary::MethodHandleNatives_klass(),
2787 vmSymbols::linkMethodHandleConstant_name(),
2788 vmSymbols::linkMethodHandleConstant_signature(),
2789 &args, CHECK_(empty));
2790 return Handle(THREAD, (oop) result.get_jobject());
2791 }
2792
2793 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2794 // name and signature, as interpreted relative to the given class loader.
2795 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2796 Handle bootstrap_specifier,
2797 Symbol* name,
2798 Symbol* type,
2799 Handle *appendix_result,
2800 Handle *method_type_result,
2801 TRAPS) {
2802 methodHandle empty;
2803 Handle bsm, info;
2804 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2805 bsm = bootstrap_specifier;
2806 } else {
2807 assert(bootstrap_specifier->is_objArray(), "");
2808 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2809 int len = args->length();
2810 assert(len >= 1, "");
2811 bsm = Handle(THREAD, args->obj_at(0));
2812 if (len > 1) {
2813 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2814 for (int i = 1; i < len; i++)
2815 args1->obj_at_put(i-1, args->obj_at(i));
2816 info = Handle(THREAD, args1);
2817 }
2818 }
2819 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2820 "caller must supply a valid BSM");
2821
2822 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2823 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2824
2825 // This should not happen. JDK code should take care of that.
2826 if (caller == NULL || method_type.is_null()) {
2827 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2828 }
2829
2830 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2831 assert(appendix_box->obj_at(0) == NULL, "");
2832
2833 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2834 JavaCallArguments args;
2835 args.push_oop(Handle(THREAD, caller->java_mirror()));
2836 args.push_oop(bsm);
2837 args.push_oop(method_name);
2838 args.push_oop(method_type);
2839 args.push_oop(info);
2840 args.push_oop(appendix_box);
2841 JavaValue result(T_OBJECT);
2842 JavaCalls::call_static(&result,
2843 SystemDictionary::MethodHandleNatives_klass(),
2844 vmSymbols::linkCallSite_name(),
2845 vmSymbols::linkCallSite_signature(),
2846 &args, CHECK_(empty));
2847 Handle mname(THREAD, (oop) result.get_jobject());
2848 (*method_type_result) = method_type;
2849 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2850 }
2851
2852 // Protection domain cache table handling
2853
2854 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2855 return _pd_cache_table->get(protection_domain);
2856 }
2857
2858 void SystemDictionary::reorder_dictionary_for_sharing() {
2859 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2860 }
2861
2862 size_t SystemDictionary::count_bytes_for_buckets() {
2863 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2864 }
2865
2866 size_t SystemDictionary::count_bytes_for_table() {
2867 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2868 }
2869
2870 void SystemDictionary::copy_buckets(char* top, char* end) {
2871 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2872 }
2873
2874 void SystemDictionary::copy_table(char* top, char* end) {
2875 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2876 }
2877
2878 // ----------------------------------------------------------------------------
2879 void SystemDictionary::print_shared(outputStream *st) {
2880 shared_dictionary()->print_on(st);
2881 }
2882
2883 void SystemDictionary::print_on(outputStream *st) {
2884 if (shared_dictionary() != NULL) {
2885 st->print_cr("Shared Dictionary");
2886 shared_dictionary()->print_on(st);
2887 st->cr();
2888 }
2889
2890 GCMutexLocker mu(SystemDictionary_lock);
2891
2892 ClassLoaderDataGraph::print_dictionary(st);
2893
2894 // Placeholders
2895 placeholders()->print_on(st);
2896 st->cr();
2897
2898 // loader constraints - print under SD_lock
2899 constraints()->print_on(st);
2900 st->cr();
2901
2902 _pd_cache_table->print_on(st);
2903 st->cr();
2904 }
2905
2906 void SystemDictionary::verify() {
2907 guarantee(constraints() != NULL,
2908 "Verify of loader constraints failed");
2909 guarantee(placeholders()->number_of_entries() >= 0,
2910 "Verify of placeholders failed");
2911
2912 GCMutexLocker mu(SystemDictionary_lock);
2913
2914 // Verify dictionary
2915 ClassLoaderDataGraph::verify_dictionary();
2916
2917 placeholders()->verify();
2918
2919 // Verify constraint table
2920 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2921 constraints()->verify(placeholders());
2922
2923 _pd_cache_table->verify();
2924 }
2925
2926 void SystemDictionary::dump(outputStream *st, bool verbose) {
2927 assert_locked_or_safepoint(SystemDictionary_lock);
2928 if (verbose) {
2929 print_on(st);
2930 } else {
2931 if (shared_dictionary() != NULL) {
2932 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2933 }
2934 ClassLoaderDataGraph::print_dictionary_statistics(st);
2935 placeholders()->print_table_statistics(st, "Placeholder Table");
2936 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2937 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2938 }
2939 }
2940
2941 // Utility for dumping dictionaries.
2942 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2943 DCmdWithParser(output, heap),
2944 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2945 "BOOLEAN", false, "false") {
2946 _dcmdparser.add_dcmd_option(&_verbose);
2947 }
2948
2949 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2950 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2951 _verbose.value());
2952 VMThread::execute(&dumper);
2953 }
2954
2955 int SystemDictionaryDCmd::num_arguments() {
2956 ResourceMark rm;
2957 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2958 if (dcmd != NULL) {
2959 DCmdMark mark(dcmd);
2960 return dcmd->_dcmdparser.num_arguments();
2961 } else {
2962 return 0;
2963 }
2964 }
2965
2966 class CombineDictionariesClosure : public CLDClosure {
2967 private:
2968 Dictionary* _master_dictionary;
2969 public:
2970 CombineDictionariesClosure(Dictionary* master_dictionary) :
2971 _master_dictionary(master_dictionary) {}
2972 void do_cld(ClassLoaderData* cld) {
2973 ResourceMark rm;
2974 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2975 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
2976 Dictionary* curr_dictionary = cld->dictionary();
2977 DictionaryEntry* p = curr_dictionary->bucket(i);
2978 while (p != NULL) {
2979 Symbol* name = p->instance_klass()->name();
2980 unsigned int d_hash = _master_dictionary->compute_hash(name);
2981 int d_index = _master_dictionary->hash_to_index(d_hash);
2982 DictionaryEntry* next = p->next();
2983 if (p->literal()->class_loader_data() != cld) {
2984 // This is an initiating class loader entry; don't use it
2985 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
2986 curr_dictionary->free_entry(p);
2987 } else {
2988 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
2989 curr_dictionary->unlink_entry(p);
2990 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
2991 _master_dictionary->add_entry(d_index, p);
2992 }
2993 p = next;
2994 }
2995 *curr_dictionary->bucket_addr(i) = NULL;
2996 }
2997 }
2998 }
2999 };
3000
3001 // Combining platform and system loader dictionaries into boot loader dictionaries.
3002 // During run time, we only have one shared dictionary.
3003 void SystemDictionary::combine_shared_dictionaries() {
3004 assert(DumpSharedSpaces, "dump time only");
3005 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3006 CombineDictionariesClosure cdc(master_dictionary);
3007 ClassLoaderDataGraph::cld_do(&cdc);
3008
3009 // These tables are no longer valid or necessary. Keeping them around will
3010 // cause SystemDictionary::verify() to fail. Let's empty them.
3011 _placeholders = new PlaceholderTable(_placeholder_table_size);
3012 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3013
3014 NOT_PRODUCT(SystemDictionary::verify());
3015 }
3016
3017 // caller needs ResourceMark
3018 const char* SystemDictionary::loader_name(const oop loader) {
3019 return ((loader) == NULL ? "<bootloader>" :
3020 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3021 }
3022
3023 // caller needs ResourceMark
3024 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3025 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3026 SystemDictionary::loader_name(loader_data->class_loader()));
3027 }