1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/methodData.hpp"
60 #include "oops/objArrayKlass.hpp"
61 #include "oops/objArrayOop.inline.hpp"
62 #include "oops/oop.inline.hpp"
63 #include "oops/symbol.hpp"
64 #include "oops/typeArrayKlass.hpp"
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_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118
119 // ----------------------------------------------------------------------------
120 // Java-level SystemLoader and PlatformLoader
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader;
124 }
125
126 oop SystemDictionary::java_platform_loader() {
127 return _java_platform_loader;
128 }
129
130 void SystemDictionary::compute_java_loaders(TRAPS) {
131 JavaValue result(T_OBJECT);
132 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
133 JavaCalls::call_static(&result,
134 class_loader_klass,
135 vmSymbols::getSystemClassLoader_name(),
136 vmSymbols::void_classloader_signature(),
137 CHECK);
138
139 _java_system_loader = (oop)result.get_jobject();
140
141 JavaCalls::call_static(&result,
142 class_loader_klass,
143 vmSymbols::getPlatformClassLoader_name(),
144 vmSymbols::void_classloader_signature(),
145 CHECK);
146
147 _java_platform_loader = (oop)result.get_jobject();
148
149 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
150 }
151
152 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
153 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
154 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
155 }
156
157 // ----------------------------------------------------------------------------
158 // Parallel class loading check
159
160 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
161 if (class_loader.is_null()) return true;
162 if (AlwaysLockClassLoader) return false;
163 return java_lang_ClassLoader::parallelCapable(class_loader());
164 }
165 // ----------------------------------------------------------------------------
166 // ParallelDefineClass flag does not apply to bootclass loader
167 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
168 if (class_loader.is_null()) return false;
169 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
170 return true;
171 }
172 return false;
173 }
174
175 // Returns true if the passed class loader is the builtin application class loader
176 // or a custom system class loader. A customer system class loader can be
177 // specified via -Djava.system.class.loader.
178 bool SystemDictionary::is_system_class_loader(oop class_loader) {
179 if (class_loader == NULL) {
180 return false;
181 }
182 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
183 class_loader == _java_system_loader);
184 }
185
186 // Returns true if the passed class loader is the platform class loader.
187 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
188 if (class_loader == NULL) {
189 return false;
190 }
191 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
192 }
193
194 // ----------------------------------------------------------------------------
195 // Resolving of classes
196
197 // Forwards to resolve_or_null
198
199 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
200 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
201 if (HAS_PENDING_EXCEPTION || klass == NULL) {
202 // can return a null klass
203 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
204 }
205 return klass;
206 }
207
208 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
209 bool throw_error,
210 Klass* klass, TRAPS) {
211 if (HAS_PENDING_EXCEPTION) {
212 // If we have a pending exception we forward it to the caller, unless throw_error is true,
213 // in which case we have to check whether the pending exception is a ClassNotFoundException,
214 // and if so convert it to a NoClassDefFoundError
215 // And chain the original ClassNotFoundException
216 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
217 ResourceMark rm(THREAD);
218 assert(klass == NULL, "Should not have result with exception pending");
219 Handle e(THREAD, PENDING_EXCEPTION);
220 CLEAR_PENDING_EXCEPTION;
221 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
222 } else {
223 return NULL;
224 }
225 }
226 // Class not found, throw appropriate error or exception depending on value of throw_error
227 if (klass == NULL) {
228 ResourceMark rm(THREAD);
229 if (throw_error) {
230 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
231 } else {
232 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
233 }
234 }
235 return klass;
236 }
237
238
239 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
240 bool throw_error, TRAPS)
241 {
242 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
243 }
244
245
246 // Forwards to resolve_instance_class_or_null
247
248 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
249 assert(THREAD->can_call_java(),
250 "can not load classes with compiler thread: class=%s, classloader=%s",
251 class_name->as_C_string(),
252 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
253 if (FieldType::is_array(class_name)) {
254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
255 } else if (FieldType::is_obj(class_name)) {
256 ResourceMark rm(THREAD);
257 // Ignore wrapping L and ;.
258 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
259 class_name->utf8_length() - 2, CHECK_NULL);
260 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
261 } else {
262 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
263 }
264 }
265
266 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
267 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
268 }
269
270 // Forwards to resolve_instance_class_or_null
271
272 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
273 Handle class_loader,
274 Handle protection_domain,
275 TRAPS) {
276 assert(FieldType::is_array(class_name), "must be array");
277 Klass* k = NULL;
278 FieldArrayInfo fd;
279 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
280 // of this call
281 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
282 if (t == T_OBJECT) {
283 // naked oop "k" is OK here -- we assign back into it
284 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
285 class_loader,
286 protection_domain,
287 CHECK_NULL);
288 if (k != NULL) {
289 k = k->array_klass(fd.dimension(), CHECK_NULL);
290 }
291 } else {
292 k = Universe::typeArrayKlassObj(t);
293 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
294 }
295 return k;
296 }
297
298
299 // Must be called for any super-class or super-interface resolution
300 // during class definition to allow class circularity checking
301 // super-interface callers:
302 // parse_interfaces - for defineClass & jvmtiRedefineClasses
303 // super-class callers:
304 // ClassFileParser - for defineClass & jvmtiRedefineClasses
305 // load_shared_class - while loading a class from shared archive
306 // resolve_instance_class_or_null:
307 // via: handle_parallel_super_load
308 // when resolving a class that has an existing placeholder with
309 // a saved superclass [i.e. a defineClass is currently in progress]
310 // if another thread is trying to resolve the class, it must do
311 // super-class checks on its own thread to catch class circularity
312 // This last call is critical in class circularity checking for cases
313 // where classloading is delegated to different threads and the
314 // classloader lock is released.
315 // Take the case: Base->Super->Base
316 // 1. If thread T1 tries to do a defineClass of class Base
317 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
318 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
319 // so it tries to load Super
320 // 3. If we load the class internally, or user classloader uses same thread
321 // loadClassFromxxx or defineClass via parseClassFile Super ...
322 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
323 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
324 // 3.4 calls resolve_super_or_fail Base
325 // 3.5 finds T1,Base -> throws class circularity
326 //OR 4. If T2 tries to resolve Super via defineClass Super ...
327 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
328 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
329 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
330 // 4.4 finds T2, Super -> throws class circularity
331 // Must be called, even if superclass is null, since this is
332 // where the placeholder entry is created which claims this
333 // thread is loading this class/classloader.
334 // Be careful when modifying this code: once you have run
335 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
336 // you need to find_and_remove it before returning.
337 // So be careful to not exit with a CHECK_ macro betweeen these calls.
338 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
339 Symbol* class_name,
340 Handle class_loader,
341 Handle protection_domain,
342 bool is_superclass,
343 TRAPS) {
344 #if INCLUDE_CDS
345 if (DumpSharedSpaces) {
346 // Special processing for CDS dump time.
347 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
348 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
349 if (k) {
350 return k;
351 }
352 }
353 #endif // INCLUDE_CDS
354
355 // Double-check, if child class is already loaded, just return super-class,interface
356 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
357 // dictionary.
358 // Make sure there's a placeholder for the *child* before resolving.
359 // Used as a claim that this thread is currently loading superclass/classloader
360 // Used here for ClassCircularity checks and also for heap verification
361 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
362 // Must check ClassCircularity before checking if super class is already loaded.
363 //
364 // We might not already have a placeholder if this child_name was
365 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
366 // the name of the class might not be known until the stream is actually
367 // parsed.
368 // Bugs 4643874, 4715493
369
370 ClassLoaderData* loader_data = class_loader_data(class_loader);
371 Dictionary* dictionary = loader_data->dictionary();
372 unsigned int d_hash = dictionary->compute_hash(child_name);
373 unsigned int p_hash = placeholders()->compute_hash(child_name);
374 int p_index = placeholders()->hash_to_index(p_hash);
375 // can't throw error holding a lock
376 bool child_already_loaded = false;
377 bool throw_circularity_error = false;
378 {
379 MutexLocker mu(SystemDictionary_lock, THREAD);
380 Klass* childk = find_class(d_hash, child_name, dictionary);
381 Klass* quicksuperk;
382 // to support // loading: if child done loading, just return superclass
383 // if class_name, & class_loader don't match:
384 // if initial define, SD update will give LinkageError
385 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
386 // so we don't throw an exception here.
387 // see: nsk redefclass014 & java.lang.instrument Instrument032
388 if ((childk != NULL ) && (is_superclass) &&
389 ((quicksuperk = childk->super()) != NULL) &&
390
391 ((quicksuperk->name() == class_name) &&
392 (quicksuperk->class_loader() == class_loader()))) {
393 return quicksuperk;
394 } else {
395 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
396 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
397 throw_circularity_error = true;
398 }
399 }
400 if (!throw_circularity_error) {
401 // Be careful not to exit resolve_super
402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
403 }
404 }
405 if (throw_circularity_error) {
406 ResourceMark rm(THREAD);
407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
408 }
409
410 // java.lang.Object should have been found above
411 assert(class_name != NULL, "null super class for resolving");
412 // Resolve the super class or interface, check results on return
413 Klass* superk = SystemDictionary::resolve_or_null(class_name,
414 class_loader,
415 protection_domain,
416 THREAD);
417
418 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
419 // It is no longer necessary to keep the placeholder table alive until update_dictionary
420 // or error. GC used to walk the placeholder table as strong roots.
421 // The instanceKlass is kept alive because the class loader is on the stack,
422 // which keeps the loader_data alive, as well as all instanceKlasses in
423 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
424 {
425 MutexLocker mu(SystemDictionary_lock, THREAD);
426 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
427 SystemDictionary_lock->notify_all();
428 }
429 if (HAS_PENDING_EXCEPTION || superk == NULL) {
430 // can null superk
431 superk = handle_resolution_exception(class_name, true, superk, THREAD);
432 }
433
434 return superk;
435 }
436
437 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
438 Handle class_loader,
439 Handle protection_domain,
440 TRAPS) {
441 if(!has_checkPackageAccess()) return;
442
443 // Now we have to call back to java to check if the initating class has access
444 JavaValue result(T_VOID);
445 LogTarget(Debug, protectiondomain) lt;
446 if (lt.is_enabled()) {
447 ResourceMark rm;
448 // Print out trace information
449 LogStream ls(lt);
450 ls.print_cr("Checking package access");
451 ls.print("class loader: "); class_loader()->print_value_on(&ls);
452 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
453 ls.print(" loading: "); klass->print_value_on(&ls);
454 ls.cr();
455 }
456
457 // This handle and the class_loader handle passed in keeps this class from
458 // being unloaded through several GC points.
459 // The class_loader handle passed in is the initiating loader.
460 Handle mirror(THREAD, klass->java_mirror());
461
462 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
463 JavaCalls::call_special(&result,
464 class_loader,
465 system_loader,
466 vmSymbols::checkPackageAccess_name(),
467 vmSymbols::class_protectiondomain_signature(),
468 mirror,
469 protection_domain,
470 THREAD);
471
472 if (HAS_PENDING_EXCEPTION) {
473 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
474 } else {
475 log_debug(protectiondomain)("granted");
476 }
477
478 if (HAS_PENDING_EXCEPTION) return;
479
480 // If no exception has been thrown, we have validated the protection domain
481 // Insert the protection domain of the initiating class into the set.
482 {
483 ClassLoaderData* loader_data = class_loader_data(class_loader);
484 Dictionary* dictionary = loader_data->dictionary();
485
486 Symbol* kn = klass->name();
487 unsigned int d_hash = dictionary->compute_hash(kn);
488
489 MutexLocker mu(SystemDictionary_lock, THREAD);
490 int d_index = dictionary->hash_to_index(d_hash);
491 dictionary->add_protection_domain(d_index, d_hash, klass,
492 protection_domain, THREAD);
493 }
494 }
495
496 // We only get here if this thread finds that another thread
497 // has already claimed the placeholder token for the current operation,
498 // but that other thread either never owned or gave up the
499 // object lock
500 // Waits on SystemDictionary_lock to indicate placeholder table updated
501 // On return, caller must recheck placeholder table state
502 //
503 // We only get here if
504 // 1) custom classLoader, i.e. not bootstrap classloader
505 // 2) custom classLoader has broken the class loader objectLock
506 // so another thread got here in parallel
507 //
508 // lockObject must be held.
509 // Complicated dance due to lock ordering:
510 // Must first release the classloader object lock to
511 // allow initial definer to complete the class definition
512 // and to avoid deadlock
513 // Reclaim classloader lock object with same original recursion count
514 // Must release SystemDictionary_lock after notify, since
515 // class loader lock must be claimed before SystemDictionary_lock
516 // to prevent deadlocks
517 //
518 // The notify allows applications that did an untimed wait() on
519 // the classloader object lock to not hang.
520 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
521 assert_lock_strong(SystemDictionary_lock);
522
523 bool calledholdinglock
524 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
525 assert(calledholdinglock,"must hold lock for notify");
526 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
527 ObjectSynchronizer::notifyall(lockObject, THREAD);
528 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
529 SystemDictionary_lock->wait();
530 SystemDictionary_lock->unlock();
531 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
532 SystemDictionary_lock->lock();
533 }
534
535 // If the class in is in the placeholder table, class loading is in progress
536 // For cases where the application changes threads to load classes, it
537 // is critical to ClassCircularity detection that we try loading
538 // the superclass on the same thread internally, so we do parallel
539 // super class loading here.
540 // This also is critical in cases where the original thread gets stalled
541 // even in non-circularity situations.
542 // Note: must call resolve_super_or_fail even if null super -
543 // to force placeholder entry creation for this class for circularity detection
544 // Caller must check for pending exception
545 // Returns non-null Klass* if other thread has completed load
546 // and we are done,
547 // If return null Klass* and no pending exception, the caller must load the class
548 InstanceKlass* SystemDictionary::handle_parallel_super_load(
549 Symbol* name, Symbol* superclassname, Handle class_loader,
550 Handle protection_domain, Handle lockObject, TRAPS) {
551
552 ClassLoaderData* loader_data = class_loader_data(class_loader);
553 Dictionary* dictionary = loader_data->dictionary();
554 unsigned int d_hash = dictionary->compute_hash(name);
555 unsigned int p_hash = placeholders()->compute_hash(name);
556 int p_index = placeholders()->hash_to_index(p_hash);
557
558 // superk is not used, resolve_super called for circularity check only
559 // This code is reached in two situations. One if this thread
560 // is loading the same class twice (e.g. ClassCircularity, or
561 // java.lang.instrument).
562 // The second is if another thread started the resolve_super first
563 // and has not yet finished.
564 // In both cases the original caller will clean up the placeholder
565 // entry on error.
566 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
567 superclassname,
568 class_loader,
569 protection_domain,
570 true,
571 CHECK_NULL);
572
573 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
574 // Serial class loaders and bootstrap classloader do wait for superclass loads
575 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
576 MutexLocker mu(SystemDictionary_lock, THREAD);
577 // Check if classloading completed while we were loading superclass or waiting
578 return find_class(d_hash, name, dictionary);
579 }
580
581 // must loop to both handle other placeholder updates
582 // and spurious notifications
583 bool super_load_in_progress = true;
584 PlaceholderEntry* placeholder;
585 while (super_load_in_progress) {
586 MutexLocker mu(SystemDictionary_lock, THREAD);
587 // Check if classloading completed while we were loading superclass or waiting
588 InstanceKlass* check = find_class(d_hash, name, dictionary);
589 if (check != NULL) {
590 // Klass is already loaded, so just return it
591 return check;
592 } else {
593 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
594 if (placeholder && placeholder->super_load_in_progress() ){
595 // We only get here if the application has released the
596 // classloader lock when another thread was in the middle of loading a
597 // superclass/superinterface for this class, and now
598 // this thread is also trying to load this class.
599 // To minimize surprises, the first thread that started to
600 // load a class should be the one to complete the loading
601 // with the classfile it initially expected.
602 // This logic has the current thread wait once it has done
603 // all the superclass/superinterface loading it can, until
604 // the original thread completes the class loading or fails
605 // If it completes we will use the resulting InstanceKlass
606 // which we will find below in the systemDictionary.
607 // We also get here for parallel bootstrap classloader
608 if (class_loader.is_null()) {
609 SystemDictionary_lock->wait();
610 } else {
611 double_lock_wait(lockObject, THREAD);
612 }
613 } else {
614 // If not in SD and not in PH, other thread's load must have failed
615 super_load_in_progress = false;
616 }
617 }
618 }
619 return NULL;
620 }
621
622 static void post_class_load_event(EventClassLoad* event,
623 const InstanceKlass* k,
624 const ClassLoaderData* init_cld) {
625 #if INCLUDE_TRACE
626 assert(event != NULL, "invariant");
627 assert(k != NULL, "invariant");
628 if (event->should_commit()) {
629 event->set_loadedClass(k);
630 event->set_definingClassLoader(k->class_loader_data());
631 event->set_initiatingClassLoader(init_cld);
632 event->commit();
633 }
634 #endif // INCLUDE_TRACE
635 }
636
637 static void class_define_event(InstanceKlass* k,
638 const ClassLoaderData* def_cld) {
639 #if INCLUDE_TRACE
640 EventClassDefine event;
641 if (event.should_commit()) {
642 event.set_definedClass(k);
643 event.set_definingClassLoader(def_cld);
644 event.commit();
645 }
646 #endif // INCLUDE_TRACE
647 }
648
649 // Be careful when modifying this code: once you have run
650 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
651 // you need to find_and_remove it before returning.
652 // So be careful to not exit with a CHECK_ macro betweeen these calls.
653 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
654 Handle class_loader,
655 Handle protection_domain,
656 TRAPS) {
657 assert(name != NULL && !FieldType::is_array(name) &&
658 !FieldType::is_obj(name), "invalid class name");
659
660 EventClassLoad class_load_start_event;
661
662 HandleMark hm(THREAD);
663
664 // Fix for 4474172; see evaluation for more details
665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
666 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
667 Dictionary* dictionary = loader_data->dictionary();
668 unsigned int d_hash = dictionary->compute_hash(name);
669
670 // Do lookup to see if class already exist and the protection domain
671 // has the right access
672 // This call uses find which checks protection domain already matches
673 // All subsequent calls use find_class, and set has_loaded_class so that
674 // before we return a result we call out to java to check for valid protection domain
675 // to allow returning the Klass* and add it to the pd_set if it is valid
676 {
677 Klass* probe = dictionary->find(d_hash, name, protection_domain);
678 if (probe != NULL) return probe;
679 }
680
681 // Non-bootstrap class loaders will call out to class loader and
682 // define via jvm/jni_DefineClass which will acquire the
683 // class loader object lock to protect against multiple threads
684 // defining the class in parallel by accident.
685 // This lock must be acquired here so the waiter will find
686 // any successful result in the SystemDictionary and not attempt
687 // the define.
688 // ParallelCapable Classloaders and the bootstrap classloader
689 // do not acquire lock here.
690 bool DoObjectLock = true;
691 if (is_parallelCapable(class_loader)) {
692 DoObjectLock = false;
693 }
694
695 unsigned int p_hash = placeholders()->compute_hash(name);
696 int p_index = placeholders()->hash_to_index(p_hash);
697
698 // Class is not in SystemDictionary so we have to do loading.
699 // Make sure we are synchronized on the class loader before we proceed
700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
701 check_loader_lock_contention(lockObject, THREAD);
702 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
703
704 // Check again (after locking) if class already exist in SystemDictionary
705 bool class_has_been_loaded = false;
706 bool super_load_in_progress = false;
707 bool havesupername = false;
708 InstanceKlass* k = NULL;
709 PlaceholderEntry* placeholder;
710 Symbol* superclassname = NULL;
711
712 {
713 MutexLocker mu(SystemDictionary_lock, THREAD);
714 InstanceKlass* check = find_class(d_hash, name, dictionary);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 class_has_been_loaded = true;
718 k = check;
719 } else {
720 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
721 if (placeholder && placeholder->super_load_in_progress()) {
722 super_load_in_progress = true;
723 if (placeholder->havesupername() == true) {
724 superclassname = placeholder->supername();
725 havesupername = true;
726 }
727 }
728 }
729 }
730
731 // If the class is in the placeholder table, class loading is in progress
732 if (super_load_in_progress && havesupername==true) {
733 k = handle_parallel_super_load(name,
734 superclassname,
735 class_loader,
736 protection_domain,
737 lockObject, THREAD);
738 if (HAS_PENDING_EXCEPTION) {
739 return NULL;
740 }
741 if (k != NULL) {
742 class_has_been_loaded = true;
743 }
744 }
745
746 bool throw_circularity_error = false;
747 if (!class_has_been_loaded) {
748 bool load_instance_added = false;
749
750 // add placeholder entry to record loading instance class
751 // Five cases:
752 // All cases need to prevent modifying bootclasssearchpath
753 // in parallel with a classload of same classname
754 // Redefineclasses uses existence of the placeholder for the duration
755 // of the class load to prevent concurrent redefinition of not completely
756 // defined classes.
757 // case 1. traditional classloaders that rely on the classloader object lock
758 // - no other need for LOAD_INSTANCE
759 // case 2. traditional classloaders that break the classloader object lock
760 // as a deadlock workaround. Detection of this case requires that
761 // this check is done while holding the classloader object lock,
762 // and that lock is still held when calling classloader's loadClass.
763 // For these classloaders, we ensure that the first requestor
764 // completes the load and other requestors wait for completion.
765 // case 3. Bootstrap classloader - don't own objectLocker
766 // This classloader supports parallelism at the classloader level,
767 // but only allows a single load of a class/classloader pair.
768 // No performance benefit and no deadlock issues.
769 // case 4. parallelCapable user level classloaders - without objectLocker
770 // Allow parallel classloading of a class/classloader pair
771
772 {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
776 if (oldprobe) {
777 // only need check_seen_thread once, not on each loop
778 // 6341374 java/lang/Instrument with -Xcomp
779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
780 throw_circularity_error = true;
781 } else {
782 // case 1: traditional: should never see load_in_progress.
783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
784
785 // case 3: bootstrap classloader: prevent futile classloading,
786 // wait on first requestor
787 if (class_loader.is_null()) {
788 SystemDictionary_lock->wait();
789 } else {
790 // case 2: traditional with broken classloader lock. wait on first
791 // requestor.
792 double_lock_wait(lockObject, THREAD);
793 }
794 // Check if classloading completed while we were waiting
795 InstanceKlass* check = find_class(d_hash, name, dictionary);
796 if (check != NULL) {
797 // Klass is already loaded, so just return it
798 k = check;
799 class_has_been_loaded = true;
800 }
801 // check if other thread failed to load and cleaned up
802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
803 }
804 }
805 }
806 }
807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
808 // case 4: parallelCapable: allow competing threads to try
809 // LOAD_INSTANCE in parallel
810
811 if (!throw_circularity_error && !class_has_been_loaded) {
812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
813 load_instance_added = true;
814 // For class loaders that do not acquire the classloader object lock,
815 // if they did not catch another thread holding LOAD_INSTANCE,
816 // need a check analogous to the acquire ObjectLocker/find_class
817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
818 // one final check if the load has already completed
819 // class loaders holding the ObjectLock shouldn't find the class here
820 InstanceKlass* check = find_class(d_hash, name, dictionary);
821 if (check != NULL) {
822 // Klass is already loaded, so return it after checking/adding protection domain
823 k = check;
824 class_has_been_loaded = true;
825 }
826 }
827 }
828
829 // must throw error outside of owning lock
830 if (throw_circularity_error) {
831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
832 ResourceMark rm(THREAD);
833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
834 }
835
836 if (!class_has_been_loaded) {
837
838 // Do actual loading
839 k = load_instance_class(name, class_loader, THREAD);
840
841 // If everything was OK (no exceptions, no null return value), and
842 // class_loader is NOT the defining loader, do a little more bookkeeping.
843 if (!HAS_PENDING_EXCEPTION && k != NULL &&
844 k->class_loader() != class_loader()) {
845
846 check_constraints(d_hash, k, class_loader, false, THREAD);
847
848 // Need to check for a PENDING_EXCEPTION again; check_constraints
849 // can throw and doesn't use the CHECK macro.
850 if (!HAS_PENDING_EXCEPTION) {
851 { // Grabbing the Compile_lock prevents systemDictionary updates
852 // during compilations.
853 MutexLocker mu(Compile_lock, THREAD);
854 update_dictionary(d_hash, p_index, p_hash,
855 k, class_loader, THREAD);
856 }
857
858 if (JvmtiExport::should_post_class_load()) {
859 Thread *thread = THREAD;
860 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
861 JvmtiExport::post_class_load((JavaThread *) thread, k);
862 }
863 }
864 }
865 } // load_instance_class
866
867 if (load_instance_added == true) {
868 // clean up placeholder entries for LOAD_INSTANCE success or error
869 // This brackets the SystemDictionary updates for both defining
870 // and initiating loaders
871 MutexLocker mu(SystemDictionary_lock, THREAD);
872 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
873 SystemDictionary_lock->notify_all();
874 }
875 }
876
877 if (HAS_PENDING_EXCEPTION || k == NULL) {
878 return NULL;
879 }
880
881 post_class_load_event(&class_load_start_event, k, loader_data);
882
883 #ifdef ASSERT
884 {
885 ClassLoaderData* loader_data = k->class_loader_data();
886 MutexLocker mu(SystemDictionary_lock, THREAD);
887 Klass* kk = find_class(name, loader_data);
888 assert(kk == k, "should be present in dictionary");
889 }
890 #endif
891
892 // return if the protection domain in NULL
893 if (protection_domain() == NULL) return k;
894
895 // Check the protection domain has the right access
896 if (dictionary->is_valid_protection_domain(d_hash, name,
897 protection_domain)) {
898 return k;
899 }
900
901 // Verify protection domain. If it fails an exception is thrown
902 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
903
904 return k;
905 }
906
907
908 // This routine does not lock the system dictionary.
909 //
910 // Since readers don't hold a lock, we must make sure that system
911 // dictionary entries are only removed at a safepoint (when only one
912 // thread is running), and are added to in a safe way (all links must
913 // be updated in an MT-safe manner).
914 //
915 // Callers should be aware that an entry could be added just after
916 // _dictionary->bucket(index) is read here, so the caller will not see
917 // the new entry.
918
919 Klass* SystemDictionary::find(Symbol* class_name,
920 Handle class_loader,
921 Handle protection_domain,
922 TRAPS) {
923
924 // The result of this call should be consistent with the result
925 // of the call to resolve_instance_class_or_null().
926 // See evaluation 6790209 and 4474172 for more details.
927 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
928 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
929
930 if (loader_data == NULL) {
931 // If the ClassLoaderData has not been setup,
932 // then the class loader has no entries in the dictionary.
933 return NULL;
934 }
935
936 Dictionary* dictionary = loader_data->dictionary();
937 unsigned int d_hash = dictionary->compute_hash(class_name);
938 return dictionary->find(d_hash, class_name,
939 protection_domain);
940 }
941
942
943 // Look for a loaded instance or array klass by name. Do not do any loading.
944 // return NULL in case of error.
945 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
946 Handle class_loader,
947 Handle protection_domain,
948 TRAPS) {
949 Klass* k = NULL;
950 assert(class_name != NULL, "class name must be non NULL");
951
952 if (FieldType::is_array(class_name)) {
953 // The name refers to an array. Parse the name.
954 // dimension and object_key in FieldArrayInfo are assigned as a
955 // side-effect of this call
956 FieldArrayInfo fd;
957 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
958 if (t != T_OBJECT) {
959 k = Universe::typeArrayKlassObj(t);
960 } else {
961 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
962 }
963 if (k != NULL) {
964 k = k->array_klass_or_null(fd.dimension());
965 }
966 } else {
967 k = find(class_name, class_loader, protection_domain, THREAD);
968 }
969 return k;
970 }
971
972 // Note: this method is much like resolve_from_stream, but
973 // does not publish the classes via the SystemDictionary.
974 // Handles unsafe_DefineAnonymousClass and redefineclasses
975 // RedefinedClasses do not add to the class hierarchy
976 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
977 Handle class_loader,
978 Handle protection_domain,
979 ClassFileStream* st,
980 const InstanceKlass* host_klass,
981 GrowableArray<Handle>* cp_patches,
982 TRAPS) {
983
984 EventClassLoad class_load_start_event;
985
986 ClassLoaderData* loader_data;
987 if (host_klass != NULL) {
988 // Create a new CLD for anonymous class, that uses the same class loader
989 // as the host_klass
990 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
991 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
992 } else {
993 loader_data = ClassLoaderData::class_loader_data(class_loader());
994 }
995
996 assert(st != NULL, "invariant");
997 assert(st->need_verify(), "invariant");
998
999 // Parse stream and create a klass.
1000 // Note that we do this even though this klass might
1001 // already be present in the SystemDictionary, otherwise we would not
1002 // throw potential ClassFormatErrors.
1003
1004 InstanceKlass* k = KlassFactory::create_from_stream(st,
1005 class_name,
1006 loader_data,
1007 protection_domain,
1008 host_klass,
1009 cp_patches,
1010 CHECK_NULL);
1011
1012 if (host_klass != NULL && k != NULL) {
1013 // If it's anonymous, initialize it now, since nobody else will.
1014
1015 {
1016 MutexLocker mu_r(Compile_lock, THREAD);
1017
1018 // Add to class hierarchy, initialize vtables, and do possible
1019 // deoptimizations.
1020 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1021
1022 // But, do not add to dictionary.
1023
1024 // compiled code dependencies need to be validated anyway
1025 notice_modification();
1026 }
1027
1028 // Rewrite and patch constant pool here.
1029 k->link_class(CHECK_NULL);
1030 if (cp_patches != NULL) {
1031 k->constants()->patch_resolved_references(cp_patches);
1032 }
1033 k->eager_initialize(CHECK_NULL);
1034
1035 // notify jvmti
1036 if (JvmtiExport::should_post_class_load()) {
1037 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1038 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1039 }
1040
1041 post_class_load_event(&class_load_start_event, k, loader_data);
1042 }
1043 assert(host_klass != NULL || NULL == cp_patches,
1044 "cp_patches only found with host_klass");
1045
1046 return k;
1047 }
1048
1049 // Add a klass to the system from a stream (called by jni_DefineClass and
1050 // JVM_DefineClass).
1051 // Note: class_name can be NULL. In that case we do not know the name of
1052 // the class until we have parsed the stream.
1053
1054 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1055 Handle class_loader,
1056 Handle protection_domain,
1057 ClassFileStream* st,
1058 TRAPS) {
1059 #if INCLUDE_CDS
1060 ResourceMark rm(THREAD);
1061 if (DumpSharedSpaces && !class_loader.is_null() &&
1062 !UseAppCDS && (strcmp(class_name->as_C_string(), "Unnamed") != 0)
1063 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1064 // class, which is used by MethodHandles).
1065 #if INCLUDE_JVMCI
1066 // Need to define the class if force initialization of JVMCI runtime. Otherwise the <clinit> of the
1067 // JVMCI class will result in ClassNotFoundException.
1068 && !Arguments::is_force_init_jvmci_runtime()) {
1069 #else
1070 ) {
1071 #endif // INCLUDE_JVMCI
1072 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1073 }
1074 #endif // INCLUDE_CDS
1075
1076 HandleMark hm(THREAD);
1077
1078 // Classloaders that support parallelism, e.g. bootstrap classloader,
1079 // do not acquire lock here
1080 bool DoObjectLock = true;
1081 if (is_parallelCapable(class_loader)) {
1082 DoObjectLock = false;
1083 }
1084
1085 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1086
1087 // Make sure we are synchronized on the class loader before we proceed
1088 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1089 check_loader_lock_contention(lockObject, THREAD);
1090 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1091
1092 assert(st != NULL, "invariant");
1093
1094 // Parse the stream and create a klass.
1095 // Note that we do this even though this klass might
1096 // already be present in the SystemDictionary, otherwise we would not
1097 // throw potential ClassFormatErrors.
1098 InstanceKlass* k = NULL;
1099
1100 #if INCLUDE_CDS
1101 if (!DumpSharedSpaces) {
1102 k = SystemDictionaryShared::lookup_from_stream(class_name,
1103 class_loader,
1104 protection_domain,
1105 st,
1106 CHECK_NULL);
1107 }
1108 #endif
1109
1110 if (k == NULL) {
1111 if (st->buffer() == NULL) {
1112 return NULL;
1113 }
1114 k = KlassFactory::create_from_stream(st,
1115 class_name,
1116 loader_data,
1117 protection_domain,
1118 NULL, // host_klass
1119 NULL, // cp_patches
1120 CHECK_NULL);
1121 }
1122
1123 assert(k != NULL, "no klass created");
1124 Symbol* h_name = k->name();
1125 assert(class_name == NULL || class_name == h_name, "name mismatch");
1126
1127 // Add class just loaded
1128 // If a class loader supports parallel classloading handle parallel define requests
1129 // find_or_define_instance_class may return a different InstanceKlass
1130 if (is_parallelCapable(class_loader)) {
1131 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1132 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1133 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1134 assert(defined_k != NULL, "Should have a klass if there's no exception");
1135 loader_data->add_to_deallocate_list(k);
1136 k = defined_k;
1137 }
1138 } else {
1139 define_instance_class(k, THREAD);
1140 }
1141
1142 // If defining the class throws an exception register 'k' for cleanup.
1143 if (HAS_PENDING_EXCEPTION) {
1144 assert(k != NULL, "Must have an instance klass here!");
1145 loader_data->add_to_deallocate_list(k);
1146 return NULL;
1147 }
1148
1149 // Make sure we have an entry in the SystemDictionary on success
1150 debug_only( {
1151 MutexLocker mu(SystemDictionary_lock, THREAD);
1152
1153 Klass* check = find_class(h_name, k->class_loader_data());
1154 assert(check == k, "should be present in the dictionary");
1155 } );
1156
1157 return k;
1158 }
1159
1160 #if INCLUDE_CDS
1161 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1162 int number_of_entries) {
1163 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1164 "bad shared dictionary size.");
1165 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1166 _shared_dictionary_size, t, number_of_entries);
1167 }
1168
1169
1170 // If there is a shared dictionary, then find the entry for the
1171 // given shared system class, if any.
1172
1173 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1174 if (shared_dictionary() != NULL) {
1175 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1176 int d_index = shared_dictionary()->hash_to_index(d_hash);
1177
1178 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1179 } else {
1180 return NULL;
1181 }
1182 }
1183
1184
1185 // Load a class from the shared spaces (found through the shared system
1186 // dictionary). Force the superclass and all interfaces to be loaded.
1187 // Update the class definition to include sibling classes and no
1188 // subclasses (yet). [Classes in the shared space are not part of the
1189 // object hierarchy until loaded.]
1190
1191 InstanceKlass* SystemDictionary::load_shared_class(
1192 Symbol* class_name, Handle class_loader, TRAPS) {
1193 InstanceKlass* ik = find_shared_class(class_name);
1194 // Make sure we only return the boot class for the NULL classloader.
1195 if (ik != NULL &&
1196 ik->is_shared_boot_class() && class_loader.is_null()) {
1197 Handle protection_domain;
1198 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1199 }
1200 return NULL;
1201 }
1202
1203 // Check if a shared class can be loaded by the specific classloader:
1204 //
1205 // NULL classloader:
1206 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1207 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1208 // be defined in an unnamed module.
1209 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1210 InstanceKlass* ik,
1211 Handle class_loader, TRAPS) {
1212 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1213 "Cannot use sharing if java.base is patched");
1214 ResourceMark rm;
1215 int path_index = ik->shared_classpath_index();
1216 ClassLoaderData* loader_data = class_loader_data(class_loader);
1217 if (path_index < 0) {
1218 // path_index < 0 indicates that the class is intended for a custom loader
1219 // and should not be loaded by boot/platform/app loaders
1220 if (loader_data->is_builtin_class_loader_data()) {
1221 return false;
1222 } else {
1223 return true;
1224 }
1225 }
1226 SharedClassPathEntry* ent =
1227 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1228 if (!Universe::is_module_initialized()) {
1229 assert(ent != NULL && ent->is_modules_image(),
1230 "Loading non-bootstrap classes before the module system is initialized");
1231 assert(class_loader.is_null(), "sanity");
1232 return true;
1233 }
1234 // Get the pkg_entry from the classloader
1235 TempNewSymbol pkg_name = NULL;
1236 PackageEntry* pkg_entry = NULL;
1237 ModuleEntry* mod_entry = NULL;
1238 const char* pkg_string = NULL;
1239 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1240 if (pkg_name != NULL) {
1241 pkg_string = pkg_name->as_C_string();
1242 if (loader_data != NULL) {
1243 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1244 }
1245 if (pkg_entry != NULL) {
1246 mod_entry = pkg_entry->module();
1247 }
1248 }
1249
1250 // If the archived class is from a module that has been patched at runtime,
1251 // the class cannot be loaded from the archive.
1252 if (mod_entry != NULL && mod_entry->is_patched()) {
1253 return false;
1254 }
1255
1256 if (class_loader.is_null()) {
1257 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1258 // The NULL classloader can load archived class originated from the
1259 // "modules" jimage and the -Xbootclasspath/a. For class from the
1260 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1261 // by the NULL classloader.
1262 if (mod_entry != NULL) {
1263 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1264 // ModuleEntry's location agrees with the archived class' origination.
1265 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1266 return true; // Module class from the "module" jimage
1267 }
1268 }
1269
1270 // If the archived class is not from the "module" jimage, the class can be
1271 // loaded by the NULL classloader if
1272 //
1273 // 1. the class is from the unamed package
1274 // 2. or, the class is not from a module defined in the NULL classloader
1275 // 3. or, the class is from an unamed module
1276 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1277 // the class is from the -Xbootclasspath/a
1278 if (pkg_string == NULL ||
1279 pkg_entry == NULL ||
1280 pkg_entry->in_unnamed_module()) {
1281 assert(mod_entry == NULL ||
1282 mod_entry == loader_data->unnamed_module(),
1283 "the unnamed module is not defined in the classloader");
1284 return true;
1285 }
1286 }
1287 return false;
1288 } else {
1289 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1290 ik, class_loader, pkg_string, pkg_name,
1291 pkg_entry, mod_entry, CHECK_(false));
1292 return res;
1293 }
1294 }
1295
1296 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1297 Handle class_loader,
1298 Handle protection_domain, TRAPS) {
1299
1300 if (ik != NULL) {
1301 Symbol* class_name = ik->name();
1302
1303 bool visible = is_shared_class_visible(
1304 class_name, ik, class_loader, CHECK_NULL);
1305 if (!visible) {
1306 return NULL;
1307 }
1308
1309 // Resolve the superclass and interfaces. They must be the same
1310 // as in dump time, because the layout of <ik> depends on
1311 // the specific layout of ik->super() and ik->local_interfaces().
1312 //
1313 // If unexpected superclass or interfaces are found, we cannot
1314 // load <ik> from the shared archive.
1315
1316 if (ik->super() != NULL) {
1317 Symbol* cn = ik->super()->name();
1318 Klass *s = resolve_super_or_fail(class_name, cn,
1319 class_loader, protection_domain, true, CHECK_NULL);
1320 if (s != ik->super()) {
1321 // The dynamically resolved super class is not the same as the one we used during dump time,
1322 // so we cannot use ik.
1323 return NULL;
1324 } else {
1325 assert(s->is_shared(), "must be");
1326 }
1327 }
1328
1329 Array<Klass*>* interfaces = ik->local_interfaces();
1330 int num_interfaces = interfaces->length();
1331 for (int index = 0; index < num_interfaces; index++) {
1332 Klass* k = interfaces->at(index);
1333 Symbol* name = k->name();
1334 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1335 if (k != i) {
1336 // The dynamically resolved interface class is not the same as the one we used during dump time,
1337 // so we cannot use ik.
1338 return NULL;
1339 } else {
1340 assert(i->is_shared(), "must be");
1341 }
1342 }
1343
1344 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1345 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1346 if (new_ik != NULL) {
1347 // The class is changed by CFLH. Return the new class. The shared class is
1348 // not used.
1349 return new_ik;
1350 }
1351
1352 // Adjust methods to recover missing data. They need addresses for
1353 // interpreter entry points and their default native method address
1354 // must be reset.
1355
1356 // Updating methods must be done under a lock so multiple
1357 // threads don't update these in parallel
1358 //
1359 // Shared classes are all currently loaded by either the bootstrap or
1360 // internal parallel class loaders, so this will never cause a deadlock
1361 // on a custom class loader lock.
1362
1363 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1364 {
1365 HandleMark hm(THREAD);
1366 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1367 check_loader_lock_contention(lockObject, THREAD);
1368 ObjectLocker ol(lockObject, THREAD, true);
1369 // prohibited package check assumes all classes loaded from archive call
1370 // restore_unshareable_info which calls ik->set_package()
1371 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1372 }
1373
1374 ik->print_class_load_logging(loader_data, NULL, NULL);
1375
1376 // For boot loader, ensure that GetSystemPackage knows that a class in this
1377 // package was loaded.
1378 if (class_loader.is_null()) {
1379 int path_index = ik->shared_classpath_index();
1380 ResourceMark rm;
1381 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1382 }
1383
1384 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1385 // Only dump the classes that can be stored into CDS archive
1386 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1387 ResourceMark rm(THREAD);
1388 classlist_file->print_cr("%s", ik->name()->as_C_string());
1389 classlist_file->flush();
1390 }
1391 }
1392
1393 // notify a class loaded from shared object
1394 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1395 }
1396
1397 ik->set_has_passed_fingerprint_check(false);
1398 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1399 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1400 uint64_t cds_fp = ik->get_stored_fingerprint();
1401 if (aot_fp != 0 && aot_fp == cds_fp) {
1402 // This class matches with a class saved in an AOT library
1403 ik->set_has_passed_fingerprint_check(true);
1404 } else {
1405 ResourceMark rm;
1406 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1407 }
1408 }
1409 return ik;
1410 }
1411
1412 void SystemDictionary::clear_invoke_method_table() {
1413 SymbolPropertyEntry* spe = NULL;
1414 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1415 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1416 while (p != NULL) {
1417 spe = p;
1418 p = p->next();
1419 _invoke_method_table->free_entry(spe);
1420 }
1421 }
1422 }
1423 #endif // INCLUDE_CDS
1424
1425 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1426
1427 if (class_loader.is_null()) {
1428 ResourceMark rm;
1429 PackageEntry* pkg_entry = NULL;
1430 bool search_only_bootloader_append = false;
1431 ClassLoaderData *loader_data = class_loader_data(class_loader);
1432
1433 // Find the package in the boot loader's package entry table.
1434 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1435 if (pkg_name != NULL) {
1436 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1437 }
1438
1439 // Prior to attempting to load the class, enforce the boot loader's
1440 // visibility boundaries.
1441 if (!Universe::is_module_initialized()) {
1442 // During bootstrapping, prior to module initialization, any
1443 // class attempting to be loaded must be checked against the
1444 // java.base packages in the boot loader's PackageEntryTable.
1445 // No class outside of java.base is allowed to be loaded during
1446 // this bootstrapping window.
1447 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1448 // Class is either in the unnamed package or in
1449 // a named package within the unnamed module. Either
1450 // case is outside of java.base, do not attempt to
1451 // load the class post java.base definition. If
1452 // java.base has not been defined, let the class load
1453 // and its package will be checked later by
1454 // ModuleEntryTable::verify_javabase_packages.
1455 if (ModuleEntryTable::javabase_defined()) {
1456 return NULL;
1457 }
1458 } else {
1459 // Check that the class' package is defined within java.base.
1460 ModuleEntry* mod_entry = pkg_entry->module();
1461 Symbol* mod_entry_name = mod_entry->name();
1462 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1463 return NULL;
1464 }
1465 }
1466 } else {
1467 // After the module system has been initialized, check if the class'
1468 // package is in a module defined to the boot loader.
1469 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1470 // Class is either in the unnamed package, in a named package
1471 // within a module not defined to the boot loader or in a
1472 // a named package within the unnamed module. In all cases,
1473 // limit visibility to search for the class only in the boot
1474 // loader's append path.
1475 search_only_bootloader_append = true;
1476 }
1477 }
1478
1479 // Prior to bootstrapping's module initialization, never load a class outside
1480 // of the boot loader's module path
1481 assert(Universe::is_module_initialized() ||
1482 !search_only_bootloader_append,
1483 "Attempt to load a class outside of boot loader's module path");
1484
1485 // Search the shared system dictionary for classes preloaded into the
1486 // shared spaces.
1487 InstanceKlass* k = NULL;
1488 {
1489 #if INCLUDE_CDS
1490 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1491 k = load_shared_class(class_name, class_loader, THREAD);
1492 #endif
1493 }
1494
1495 if (k == NULL) {
1496 // Use VM class loader
1497 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1498 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1499 }
1500
1501 // find_or_define_instance_class may return a different InstanceKlass
1502 if (k != NULL) {
1503 InstanceKlass* defined_k =
1504 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1505 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1506 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1507 assert(defined_k != NULL, "Should have a klass if there's no exception");
1508 loader_data->add_to_deallocate_list(k);
1509 k = defined_k;
1510 } else if (HAS_PENDING_EXCEPTION) {
1511 loader_data->add_to_deallocate_list(k);
1512 return NULL;
1513 }
1514 }
1515 return k;
1516 } else {
1517 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1518 ResourceMark rm(THREAD);
1519
1520 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1521 JavaThread* jt = (JavaThread*) THREAD;
1522
1523 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1524 ClassLoader::perf_app_classload_selftime(),
1525 ClassLoader::perf_app_classload_count(),
1526 jt->get_thread_stat()->perf_recursion_counts_addr(),
1527 jt->get_thread_stat()->perf_timers_addr(),
1528 PerfClassTraceTime::CLASS_LOAD);
1529
1530 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1531 // Translate to external class name format, i.e., convert '/' chars to '.'
1532 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1533
1534 JavaValue result(T_OBJECT);
1535
1536 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1537
1538 // Call public unsynchronized loadClass(String) directly for all class loaders.
1539 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1540 // acquire a class-name based lock rather than the class loader object lock.
1541 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1542 JavaCalls::call_virtual(&result,
1543 class_loader,
1544 spec_klass,
1545 vmSymbols::loadClass_name(),
1546 vmSymbols::string_class_signature(),
1547 string,
1548 CHECK_NULL);
1549
1550 assert(result.get_type() == T_OBJECT, "just checking");
1551 oop obj = (oop) result.get_jobject();
1552
1553 // Primitive classes return null since forName() can not be
1554 // used to obtain any of the Class objects representing primitives or void
1555 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1556 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1557 // For user defined Java class loaders, check that the name returned is
1558 // the same as that requested. This check is done for the bootstrap
1559 // loader when parsing the class file.
1560 if (class_name == k->name()) {
1561 return k;
1562 }
1563 }
1564 // Class is not found or has the wrong name, return NULL
1565 return NULL;
1566 }
1567 }
1568
1569 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1570
1571 HandleMark hm(THREAD);
1572 ClassLoaderData* loader_data = k->class_loader_data();
1573 Handle class_loader_h(THREAD, loader_data->class_loader());
1574
1575 // for bootstrap and other parallel classloaders don't acquire lock,
1576 // use placeholder token
1577 // If a parallelCapable class loader calls define_instance_class instead of
1578 // find_or_define_instance_class to get here, we have a timing
1579 // hole with systemDictionary updates and check_constraints
1580 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1581 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1582 compute_loader_lock_object(class_loader_h, THREAD)),
1583 "define called without lock");
1584 }
1585
1586 // Check class-loading constraints. Throw exception if violation is detected.
1587 // Grabs and releases SystemDictionary_lock
1588 // The check_constraints/find_class call and update_dictionary sequence
1589 // must be "atomic" for a specific class/classloader pair so we never
1590 // define two different instanceKlasses for that class/classloader pair.
1591 // Existing classloaders will call define_instance_class with the
1592 // classloader lock held
1593 // Parallel classloaders will call find_or_define_instance_class
1594 // which will require a token to perform the define class
1595 Symbol* name_h = k->name();
1596 Dictionary* dictionary = loader_data->dictionary();
1597 unsigned int d_hash = dictionary->compute_hash(name_h);
1598 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1599
1600 // Register class just loaded with class loader (placed in Vector)
1601 // Note we do this before updating the dictionary, as this can
1602 // fail with an OutOfMemoryError (if it does, we will *not* put this
1603 // class in the dictionary and will not update the class hierarchy).
1604 // JVMTI FollowReferences needs to find the classes this way.
1605 if (k->class_loader() != NULL) {
1606 methodHandle m(THREAD, Universe::loader_addClass_method());
1607 JavaValue result(T_VOID);
1608 JavaCallArguments args(class_loader_h);
1609 args.push_oop(Handle(THREAD, k->java_mirror()));
1610 JavaCalls::call(&result, m, &args, CHECK);
1611 }
1612
1613 // Add the new class. We need recompile lock during update of CHA.
1614 {
1615 unsigned int p_hash = placeholders()->compute_hash(name_h);
1616 int p_index = placeholders()->hash_to_index(p_hash);
1617
1618 MutexLocker mu_r(Compile_lock, THREAD);
1619
1620 // Add to class hierarchy, initialize vtables, and do possible
1621 // deoptimizations.
1622 add_to_hierarchy(k, CHECK); // No exception, but can block
1623
1624 // Add to systemDictionary - so other classes can see it.
1625 // Grabs and releases SystemDictionary_lock
1626 update_dictionary(d_hash, p_index, p_hash,
1627 k, class_loader_h, THREAD);
1628 }
1629 k->eager_initialize(THREAD);
1630
1631 // notify jvmti
1632 if (JvmtiExport::should_post_class_load()) {
1633 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1634 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1635
1636 }
1637 class_define_event(k, loader_data);
1638 }
1639
1640 // Support parallel classloading
1641 // All parallel class loaders, including bootstrap classloader
1642 // lock a placeholder entry for this class/class_loader pair
1643 // to allow parallel defines of different classes for this class loader
1644 // With AllowParallelDefine flag==true, in case they do not synchronize around
1645 // FindLoadedClass/DefineClass, calls, we check for parallel
1646 // loading for them, wait if a defineClass is in progress
1647 // and return the initial requestor's results
1648 // This flag does not apply to the bootstrap classloader.
1649 // With AllowParallelDefine flag==false, call through to define_instance_class
1650 // which will throw LinkageError: duplicate class definition.
1651 // False is the requested default.
1652 // For better performance, the class loaders should synchronize
1653 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1654 // potentially waste time reading and parsing the bytestream.
1655 // Note: VM callers should ensure consistency of k/class_name,class_loader
1656 // Be careful when modifying this code: once you have run
1657 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1658 // you need to find_and_remove it before returning.
1659 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1660 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1661 InstanceKlass* k, TRAPS) {
1662
1663 Symbol* name_h = k->name(); // passed in class_name may be null
1664 ClassLoaderData* loader_data = class_loader_data(class_loader);
1665 Dictionary* dictionary = loader_data->dictionary();
1666
1667 unsigned int d_hash = dictionary->compute_hash(name_h);
1668
1669 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1670 unsigned int p_hash = placeholders()->compute_hash(name_h);
1671 int p_index = placeholders()->hash_to_index(p_hash);
1672 PlaceholderEntry* probe;
1673
1674 {
1675 MutexLocker mu(SystemDictionary_lock, THREAD);
1676 // First check if class already defined
1677 if (is_parallelDefine(class_loader)) {
1678 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1679 if (check != NULL) {
1680 return check;
1681 }
1682 }
1683
1684 // Acquire define token for this class/classloader
1685 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1686 // Wait if another thread defining in parallel
1687 // All threads wait - even those that will throw duplicate class: otherwise
1688 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1689 // if other thread has not finished updating dictionary
1690 while (probe->definer() != NULL) {
1691 SystemDictionary_lock->wait();
1692 }
1693 // Only special cases allow parallel defines and can use other thread's results
1694 // Other cases fall through, and may run into duplicate defines
1695 // caught by finding an entry in the SystemDictionary
1696 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1697 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1698 SystemDictionary_lock->notify_all();
1699 #ifdef ASSERT
1700 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1701 assert(check != NULL, "definer missed recording success");
1702 #endif
1703 return probe->instance_klass();
1704 } else {
1705 // This thread will define the class (even if earlier thread tried and had an error)
1706 probe->set_definer(THREAD);
1707 }
1708 }
1709
1710 define_instance_class(k, THREAD);
1711
1712 Handle linkage_exception = Handle(); // null handle
1713
1714 // definer must notify any waiting threads
1715 {
1716 MutexLocker mu(SystemDictionary_lock, THREAD);
1717 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1718 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1719 if (probe != NULL) {
1720 if (HAS_PENDING_EXCEPTION) {
1721 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1722 CLEAR_PENDING_EXCEPTION;
1723 } else {
1724 probe->set_instance_klass(k);
1725 }
1726 probe->set_definer(NULL);
1727 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1728 SystemDictionary_lock->notify_all();
1729 }
1730 }
1731
1732 // Can't throw exception while holding lock due to rank ordering
1733 if (linkage_exception() != NULL) {
1734 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1735 }
1736
1737 return k;
1738 }
1739
1740 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1741 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1742 if (class_loader.is_null()) {
1743 return Handle(THREAD, _system_loader_lock_obj);
1744 } else {
1745 return class_loader;
1746 }
1747 }
1748
1749 // This method is added to check how often we have to wait to grab loader
1750 // lock. The results are being recorded in the performance counters defined in
1751 // ClassLoader::_sync_systemLoaderLockContentionRate and
1752 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1753 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1754 if (!UsePerfData) {
1755 return;
1756 }
1757
1758 assert(!loader_lock.is_null(), "NULL lock object");
1759
1760 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1761 == ObjectSynchronizer::owner_other) {
1762 // contention will likely happen, so increment the corresponding
1763 // contention counter.
1764 if (loader_lock() == _system_loader_lock_obj) {
1765 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1766 } else {
1767 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1768 }
1769 }
1770 }
1771
1772 // ----------------------------------------------------------------------------
1773 // Lookup
1774
1775 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1776 Symbol* class_name,
1777 Dictionary* dictionary) {
1778 assert_locked_or_safepoint(SystemDictionary_lock);
1779 int index = dictionary->hash_to_index(hash);
1780 return dictionary->find_class(index, hash, class_name);
1781 }
1782
1783
1784 // Basic find on classes in the midst of being loaded
1785 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1786 ClassLoaderData* loader_data) {
1787 assert_locked_or_safepoint(SystemDictionary_lock);
1788 unsigned int p_hash = placeholders()->compute_hash(class_name);
1789 int p_index = placeholders()->hash_to_index(p_hash);
1790 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1791 }
1792
1793
1794 // Used for assertions and verification only
1795 // Precalculating the hash and index is an optimization because there are many lookups
1796 // before adding the class.
1797 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1798 assert_locked_or_safepoint(SystemDictionary_lock);
1799 #ifndef ASSERT
1800 guarantee(VerifyBeforeGC ||
1801 VerifyDuringGC ||
1802 VerifyBeforeExit ||
1803 VerifyDuringStartup ||
1804 VerifyAfterGC, "too expensive");
1805 #endif
1806
1807 Dictionary* dictionary = loader_data->dictionary();
1808 unsigned int d_hash = dictionary->compute_hash(class_name);
1809 return find_class(d_hash, class_name, dictionary);
1810 }
1811
1812
1813 // ----------------------------------------------------------------------------
1814 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1815 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1816 // before a new class is used.
1817
1818 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1819 assert(k != NULL, "just checking");
1820 assert_locked_or_safepoint(Compile_lock);
1821
1822 // Link into hierachy. Make sure the vtables are initialized before linking into
1823 k->append_to_sibling_list(); // add to superklass/sibling list
1824 k->process_interfaces(THREAD); // handle all "implements" declarations
1825 k->set_init_state(InstanceKlass::loaded);
1826 // Now flush all code that depended on old class hierarchy.
1827 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1828 // Also, first reinitialize vtable because it may have gotten out of synch
1829 // while the new class wasn't connected to the class hierarchy.
1830 CodeCache::flush_dependents_on(k);
1831 }
1832
1833 // ----------------------------------------------------------------------------
1834 // GC support
1835
1836 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1837 roots_oops_do(blk, NULL);
1838 }
1839
1840
1841 #ifdef ASSERT
1842 class VerifySDReachableAndLiveClosure : public OopClosure {
1843 private:
1844 BoolObjectClosure* _is_alive;
1845
1846 template <class T> void do_oop_work(T* p) {
1847 oop obj = oopDesc::load_decode_heap_oop(p);
1848 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1849 }
1850
1851 public:
1852 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1853
1854 virtual void do_oop(oop* p) { do_oop_work(p); }
1855 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1856 };
1857 #endif
1858
1859 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1860 // Note: anonymous classes are not in the SD.
1861 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1862 GCTimer* gc_timer,
1863 bool do_cleaning) {
1864
1865
1866 bool unloading_occurred;
1867 {
1868 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1869
1870 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1871 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1872 do_cleaning);
1873 }
1874
1875 if (unloading_occurred) {
1876 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1877 constraints()->purge_loader_constraints();
1878 resolution_errors()->purge_resolution_errors();
1879 }
1880
1881 {
1882 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1883 // Oops referenced by the protection domain cache table may get unreachable independently
1884 // of the class loader (eg. cached protection domain oops). So we need to
1885 // explicitly unlink them here.
1886 _pd_cache_table->unlink(is_alive);
1887
1888 #ifdef ASSERT
1889 VerifySDReachableAndLiveClosure cl(is_alive);
1890 _pd_cache_table->oops_do(&cl);
1891 #endif
1892 }
1893
1894 if (do_cleaning) {
1895 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1896 ResolvedMethodTable::unlink(is_alive);
1897 }
1898
1899 return unloading_occurred;
1900 }
1901
1902 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1903 strong->do_oop(&_java_system_loader);
1904 strong->do_oop(&_java_platform_loader);
1905 strong->do_oop(&_system_loader_lock_obj);
1906 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1907
1908 // Do strong roots marking if the closures are the same.
1909 if (strong == weak || !ClassUnloading) {
1910 // Only the protection domain oops contain references into the heap. Iterate
1911 // over all of them.
1912 _pd_cache_table->oops_do(strong);
1913 } else {
1914 if (weak != NULL) {
1915 _pd_cache_table->oops_do(weak);
1916 }
1917 }
1918
1919 // Visit extra methods
1920 invoke_method_table()->oops_do(strong);
1921
1922 if (weak != NULL) {
1923 ResolvedMethodTable::oops_do(weak);
1924 }
1925 }
1926
1927 void SystemDictionary::oops_do(OopClosure* f) {
1928 f->do_oop(&_java_system_loader);
1929 f->do_oop(&_java_platform_loader);
1930 f->do_oop(&_system_loader_lock_obj);
1931 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1932
1933 // Only the protection domain oops contain references into the heap. Iterate
1934 // over all of them.
1935 _pd_cache_table->oops_do(f);
1936
1937 // Visit extra methods
1938 invoke_method_table()->oops_do(f);
1939
1940 ResolvedMethodTable::oops_do(f);
1941 }
1942
1943 // CDS: scan and relocate all classes in the system dictionary.
1944 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1945 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1946 }
1947
1948 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1949 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1950 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1951 it->push(well_known_klass_addr((WKID)id));
1952 }
1953 }
1954
1955 void SystemDictionary::methods_do(void f(Method*)) {
1956 // Walk methods in loaded classes
1957 ClassLoaderDataGraph::methods_do(f);
1958 // Walk method handle intrinsics
1959 invoke_method_table()->methods_do(f);
1960 }
1961
1962 class RemoveClassesClosure : public CLDClosure {
1963 public:
1964 void do_cld(ClassLoaderData* cld) {
1965 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1966 cld->dictionary()->remove_classes_in_error_state();
1967 }
1968 }
1969 };
1970
1971 void SystemDictionary::remove_classes_in_error_state() {
1972 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1973 RemoveClassesClosure rcc;
1974 ClassLoaderDataGraph::cld_do(&rcc);
1975 }
1976
1977 // ----------------------------------------------------------------------------
1978 // Lazily load klasses
1979
1980 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1981 // if multiple threads calling this function, only one thread will load
1982 // the class. The other threads will find the loaded version once the
1983 // class is loaded.
1984 Klass* aos = _abstract_ownable_synchronizer_klass;
1985 if (aos == NULL) {
1986 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1987 // Force a fence to prevent any read before the write completes
1988 OrderAccess::fence();
1989 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1990 }
1991 }
1992
1993 // ----------------------------------------------------------------------------
1994 // Initialization
1995
1996 void SystemDictionary::initialize(TRAPS) {
1997 // Allocate arrays
1998 _placeholders = new PlaceholderTable(_placeholder_table_size);
1999 _number_of_modifications = 0;
2000 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2001 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2002 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2003 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2004
2005 // Allocate private object used as system class loader lock
2006 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2007 // Initialize basic classes
2008 initialize_preloaded_classes(CHECK);
2009 }
2010
2011 // Compact table of directions on the initialization of klasses:
2012 static const short wk_init_info[] = {
2013 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2014 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2015 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2016 | (int)SystemDictionary::option ),
2017 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2018 #undef WK_KLASS_INIT_INFO
2019 0
2020 };
2021
2022 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2023 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2024 int info = wk_init_info[id - FIRST_WKID];
2025 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2026 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2027 InstanceKlass** klassp = &_well_known_klasses[id];
2028
2029 bool must_load;
2030 #if INCLUDE_JVMCI
2031 if (EnableJVMCI) {
2032 // If JVMCI is enabled we require its classes to be found.
2033 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2034 } else
2035 #endif
2036 {
2037 must_load = (init_opt < SystemDictionary::Opt);
2038 }
2039
2040 if ((*klassp) == NULL) {
2041 Klass* k;
2042 if (must_load) {
2043 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2044 } else {
2045 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2046 }
2047 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2048 }
2049 return ((*klassp) != NULL);
2050 }
2051
2052 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2053 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2054 for (int id = (int)start_id; id < (int)limit_id; id++) {
2055 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2056 int info = wk_init_info[id - FIRST_WKID];
2057 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2058 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2059
2060 initialize_wk_klass((WKID)id, opt, CHECK);
2061 }
2062
2063 // move the starting value forward to the limit:
2064 start_id = limit_id;
2065 }
2066
2067 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2068 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2069
2070 // Create the ModuleEntry for java.base. This call needs to be done here,
2071 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2072 ClassLoader::classLoader_init2(CHECK);
2073
2074 // Preload commonly used klasses
2075 WKID scan = FIRST_WKID;
2076 // first do Object, then String, Class
2077 #if INCLUDE_CDS
2078 if (UseSharedSpaces) {
2079 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2080 // Initialize the constant pool for the Object_class
2081 Object_klass()->constants()->restore_unshareable_info(CHECK);
2082 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2083 } else
2084 #endif
2085 {
2086 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2087 }
2088
2089 // Calculate offsets for String and Class classes since they are loaded and
2090 // can be used after this point.
2091 java_lang_String::compute_offsets();
2092 java_lang_Class::compute_offsets();
2093
2094 // Fixup mirrors for classes loaded before java.lang.Class.
2095 // These calls iterate over the objects currently in the perm gen
2096 // so calling them at this point is matters (not before when there
2097 // are fewer objects and not later after there are more objects
2098 // in the perm gen.
2099 Universe::initialize_basic_type_mirrors(CHECK);
2100 Universe::fixup_mirrors(CHECK);
2101
2102 // do a bunch more:
2103 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2104
2105 // Preload ref klasses and set reference types
2106 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2107 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2108
2109 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2110 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2111 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2112 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2113 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2114
2115 // JSR 292 classes
2116 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2117 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2118 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2119 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2120 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2121
2122 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2123 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2124 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2125 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2126 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2127 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2128 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2129 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2130 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2131 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2132
2133 { // Compute whether we should use checkPackageAccess or NOT
2134 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2135 _has_checkPackageAccess = (method != NULL);
2136 }
2137 }
2138
2139 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2140 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2141 BasicType SystemDictionary::box_klass_type(Klass* k) {
2142 assert(k != NULL, "");
2143 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2144 if (_box_klasses[i] == k)
2145 return (BasicType)i;
2146 }
2147 return T_OBJECT;
2148 }
2149
2150 // Constraints on class loaders. The details of the algorithm can be
2151 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2152 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2153 // that the dictionary needs to maintain a set of contraints that
2154 // must be satisfied by all classes in the dictionary.
2155 // if defining is true, then LinkageError if already in dictionary
2156 // if initiating loader, then ok if InstanceKlass matches existing entry
2157
2158 void SystemDictionary::check_constraints(unsigned int d_hash,
2159 InstanceKlass* k,
2160 Handle class_loader, bool defining,
2161 TRAPS) {
2162 const char *linkage_error1 = NULL;
2163 const char *linkage_error2 = NULL;
2164 {
2165 Symbol* name = k->name();
2166 ClassLoaderData *loader_data = class_loader_data(class_loader);
2167
2168 MutexLocker mu(SystemDictionary_lock, THREAD);
2169
2170 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2171 if (check != NULL) {
2172 // if different InstanceKlass - duplicate class definition,
2173 // else - ok, class loaded by a different thread in parallel,
2174 // we should only have found it if it was done loading and ok to use
2175 // dictionary only holds instance classes, placeholders
2176 // also holds array classes
2177
2178 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2179 if ((defining == true) || (k != check)) {
2180 linkage_error1 = "loader (instance of ";
2181 linkage_error2 = "): attempted duplicate class definition for name: \"";
2182 } else {
2183 return;
2184 }
2185 }
2186
2187 #ifdef ASSERT
2188 Symbol* ph_check = find_placeholder(name, loader_data);
2189 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2190 #endif
2191
2192 if (linkage_error1 == NULL) {
2193 if (constraints()->check_or_update(k, class_loader, name) == false) {
2194 linkage_error1 = "loader constraint violation: loader (instance of ";
2195 linkage_error2 = ") previously initiated loading for a different type with name \"";
2196 }
2197 }
2198 }
2199
2200 // Throw error now if needed (cannot throw while holding
2201 // SystemDictionary_lock because of rank ordering)
2202
2203 if (linkage_error1) {
2204 ResourceMark rm(THREAD);
2205 const char* class_loader_name = loader_name(class_loader());
2206 char* type_name = k->name()->as_C_string();
2207 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2208 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2209 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2210 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2211 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2212 }
2213 }
2214
2215
2216 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2217 // have been called.
2218 void SystemDictionary::update_dictionary(unsigned int d_hash,
2219 int p_index, unsigned int p_hash,
2220 InstanceKlass* k,
2221 Handle class_loader,
2222 TRAPS) {
2223 // Compile_lock prevents systemDictionary updates during compilations
2224 assert_locked_or_safepoint(Compile_lock);
2225 Symbol* name = k->name();
2226 ClassLoaderData *loader_data = class_loader_data(class_loader);
2227
2228 {
2229 MutexLocker mu1(SystemDictionary_lock, THREAD);
2230
2231 // See whether biased locking is enabled and if so set it for this
2232 // klass.
2233 // Note that this must be done past the last potential blocking
2234 // point / safepoint. We enable biased locking lazily using a
2235 // VM_Operation to iterate the SystemDictionary and installing the
2236 // biasable mark word into each InstanceKlass's prototype header.
2237 // To avoid race conditions where we accidentally miss enabling the
2238 // optimization for one class in the process of being added to the
2239 // dictionary, we must not safepoint after the test of
2240 // BiasedLocking::enabled().
2241 if (UseBiasedLocking && BiasedLocking::enabled()) {
2242 // Set biased locking bit for all loaded classes; it will be
2243 // cleared if revocation occurs too often for this type
2244 // NOTE that we must only do this when the class is initally
2245 // defined, not each time it is referenced from a new class loader
2246 if (k->class_loader() == class_loader()) {
2247 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2248 }
2249 }
2250
2251 // Make a new dictionary entry.
2252 Dictionary* dictionary = loader_data->dictionary();
2253 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2254 if (sd_check == NULL) {
2255 dictionary->add_klass(d_hash, name, k);
2256 notice_modification();
2257 }
2258 #ifdef ASSERT
2259 sd_check = find_class(d_hash, name, dictionary);
2260 assert (sd_check != NULL, "should have entry in dictionary");
2261 // Note: there may be a placeholder entry: for circularity testing
2262 // or for parallel defines
2263 #endif
2264 SystemDictionary_lock->notify_all();
2265 }
2266 }
2267
2268
2269 // Try to find a class name using the loader constraints. The
2270 // loader constraints might know about a class that isn't fully loaded
2271 // yet and these will be ignored.
2272 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2273 Symbol* class_name, Handle class_loader, TRAPS) {
2274
2275 // First see if it has been loaded directly.
2276 // Force the protection domain to be null. (This removes protection checks.)
2277 Handle no_protection_domain;
2278 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2279 no_protection_domain, CHECK_NULL);
2280 if (klass != NULL)
2281 return klass;
2282
2283 // Now look to see if it has been loaded elsewhere, and is subject to
2284 // a loader constraint that would require this loader to return the
2285 // klass that is already loaded.
2286 if (FieldType::is_array(class_name)) {
2287 // For array classes, their Klass*s are not kept in the
2288 // constraint table. The element Klass*s are.
2289 FieldArrayInfo fd;
2290 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2291 if (t != T_OBJECT) {
2292 klass = Universe::typeArrayKlassObj(t);
2293 } else {
2294 MutexLocker mu(SystemDictionary_lock, THREAD);
2295 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2296 }
2297 // If element class already loaded, allocate array klass
2298 if (klass != NULL) {
2299 klass = klass->array_klass_or_null(fd.dimension());
2300 }
2301 } else {
2302 MutexLocker mu(SystemDictionary_lock, THREAD);
2303 // Non-array classes are easy: simply check the constraint table.
2304 klass = constraints()->find_constrained_klass(class_name, class_loader);
2305 }
2306
2307 return klass;
2308 }
2309
2310
2311 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2312 Handle class_loader1,
2313 Handle class_loader2,
2314 Thread* THREAD) {
2315 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2316 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2317
2318 Symbol* constraint_name = NULL;
2319 if (!FieldType::is_array(class_name)) {
2320 constraint_name = class_name;
2321 } else {
2322 // For array classes, their Klass*s are not kept in the
2323 // constraint table. The element classes are.
2324 FieldArrayInfo fd;
2325 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2326 // primitive types always pass
2327 if (t != T_OBJECT) {
2328 return true;
2329 } else {
2330 constraint_name = fd.object_key();
2331 }
2332 }
2333
2334 Dictionary* dictionary1 = loader_data1->dictionary();
2335 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2336
2337 Dictionary* dictionary2 = loader_data2->dictionary();
2338 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2339
2340 {
2341 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2342 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2343 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2344 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2345 klass2, class_loader2);
2346 }
2347 }
2348
2349 // Add entry to resolution error table to record the error when the first
2350 // attempt to resolve a reference to a class has failed.
2351 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2352 Symbol* error, Symbol* message) {
2353 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2354 int index = resolution_errors()->hash_to_index(hash);
2355 {
2356 MutexLocker ml(SystemDictionary_lock, Thread::current());
2357 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2358 }
2359 }
2360
2361 // Delete a resolution error for RedefineClasses for a constant pool is going away
2362 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2363 resolution_errors()->delete_entry(pool);
2364 }
2365
2366 // Lookup resolution error table. Returns error if found, otherwise NULL.
2367 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2368 Symbol** message) {
2369 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2370 int index = resolution_errors()->hash_to_index(hash);
2371 {
2372 MutexLocker ml(SystemDictionary_lock, Thread::current());
2373 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2374 if (entry != NULL) {
2375 *message = entry->message();
2376 return entry->error();
2377 } else {
2378 return NULL;
2379 }
2380 }
2381 }
2382
2383
2384 // Signature constraints ensure that callers and callees agree about
2385 // the meaning of type names in their signatures. This routine is the
2386 // intake for constraints. It collects them from several places:
2387 //
2388 // * LinkResolver::resolve_method (if check_access is true) requires
2389 // that the resolving class (the caller) and the defining class of
2390 // the resolved method (the callee) agree on each type in the
2391 // method's signature.
2392 //
2393 // * LinkResolver::resolve_interface_method performs exactly the same
2394 // checks.
2395 //
2396 // * LinkResolver::resolve_field requires that the constant pool
2397 // attempting to link to a field agree with the field's defining
2398 // class about the type of the field signature.
2399 //
2400 // * klassVtable::initialize_vtable requires that, when a class
2401 // overrides a vtable entry allocated by a superclass, that the
2402 // overriding method (i.e., the callee) agree with the superclass
2403 // on each type in the method's signature.
2404 //
2405 // * klassItable::initialize_itable requires that, when a class fills
2406 // in its itables, for each non-abstract method installed in an
2407 // itable, the method (i.e., the callee) agree with the interface
2408 // on each type in the method's signature.
2409 //
2410 // All those methods have a boolean (check_access, checkconstraints)
2411 // which turns off the checks. This is used from specialized contexts
2412 // such as bootstrapping, dumping, and debugging.
2413 //
2414 // No direct constraint is placed between the class and its
2415 // supertypes. Constraints are only placed along linked relations
2416 // between callers and callees. When a method overrides or implements
2417 // an abstract method in a supertype (superclass or interface), the
2418 // constraints are placed as if the supertype were the caller to the
2419 // overriding method. (This works well, since callers to the
2420 // supertype have already established agreement between themselves and
2421 // the supertype.) As a result of all this, a class can disagree with
2422 // its supertype about the meaning of a type name, as long as that
2423 // class neither calls a relevant method of the supertype, nor is
2424 // called (perhaps via an override) from the supertype.
2425 //
2426 //
2427 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2428 //
2429 // Make sure all class components (including arrays) in the given
2430 // signature will be resolved to the same class in both loaders.
2431 // Returns the name of the type that failed a loader constraint check, or
2432 // NULL if no constraint failed. No exception except OOME is thrown.
2433 // Arrays are not added to the loader constraint table, their elements are.
2434 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2435 Handle loader1, Handle loader2,
2436 bool is_method, TRAPS) {
2437 // Nothing to do if loaders are the same.
2438 if (loader1() == loader2()) {
2439 return NULL;
2440 }
2441
2442 SignatureStream sig_strm(signature, is_method);
2443 while (!sig_strm.is_done()) {
2444 if (sig_strm.is_object()) {
2445 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2446 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2447 return sig;
2448 }
2449 }
2450 sig_strm.next();
2451 }
2452 return NULL;
2453 }
2454
2455
2456 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2457 Symbol* signature,
2458 TRAPS) {
2459 methodHandle empty;
2460 assert(MethodHandles::is_signature_polymorphic(iid) &&
2461 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2462 iid != vmIntrinsics::_invokeGeneric,
2463 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2464
2465 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2466 int index = invoke_method_table()->hash_to_index(hash);
2467 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2468 methodHandle m;
2469 if (spe == NULL || spe->method() == NULL) {
2470 spe = NULL;
2471 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2472 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2473 if (!Arguments::is_interpreter_only()) {
2474 // Generate a compiled form of the MH intrinsic.
2475 AdapterHandlerLibrary::create_native_wrapper(m);
2476 // Check if have the compiled code.
2477 if (!m->has_compiled_code()) {
2478 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2479 "Out of space in CodeCache for method handle intrinsic", empty);
2480 }
2481 }
2482 // Now grab the lock. We might have to throw away the new method,
2483 // if a racing thread has managed to install one at the same time.
2484 {
2485 MutexLocker ml(SystemDictionary_lock, THREAD);
2486 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2487 if (spe == NULL)
2488 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2489 if (spe->method() == NULL)
2490 spe->set_method(m());
2491 }
2492 }
2493
2494 assert(spe != NULL && spe->method() != NULL, "");
2495 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2496 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2497 "MH intrinsic invariant");
2498 return spe->method();
2499 }
2500
2501 // Helper for unpacking the return value from linkMethod and linkCallSite.
2502 static methodHandle unpack_method_and_appendix(Handle mname,
2503 Klass* accessing_klass,
2504 objArrayHandle appendix_box,
2505 Handle* appendix_result,
2506 TRAPS) {
2507 methodHandle empty;
2508 if (mname.not_null()) {
2509 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2510 if (m != NULL) {
2511 oop appendix = appendix_box->obj_at(0);
2512 if (TraceMethodHandles) {
2513 #ifndef PRODUCT
2514 ttyLocker ttyl;
2515 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2516 m->print();
2517 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2518 tty->cr();
2519 #endif //PRODUCT
2520 }
2521 (*appendix_result) = Handle(THREAD, appendix);
2522 // the target is stored in the cpCache and if a reference to this
2523 // MethodName is dropped we need a way to make sure the
2524 // class_loader containing this method is kept alive.
2525 // FIXME: the appendix might also preserve this dependency.
2526 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2527 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2528 return methodHandle(THREAD, m);
2529 }
2530 }
2531 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2532 return empty;
2533 }
2534
2535 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2536 Symbol* name,
2537 Symbol* signature,
2538 Klass* accessing_klass,
2539 Handle *appendix_result,
2540 Handle *method_type_result,
2541 TRAPS) {
2542 methodHandle empty;
2543 assert(THREAD->can_call_java() ,"");
2544 Handle method_type =
2545 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2546
2547 int ref_kind = JVM_REF_invokeVirtual;
2548 oop name_oop = StringTable::intern(name, CHECK_(empty));
2549 Handle name_str (THREAD, name_oop);
2550 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2551 assert(appendix_box->obj_at(0) == NULL, "");
2552
2553 // This should not happen. JDK code should take care of that.
2554 if (accessing_klass == NULL || method_type.is_null()) {
2555 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2556 }
2557
2558 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2559 JavaCallArguments args;
2560 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2561 args.push_int(ref_kind);
2562 args.push_oop(Handle(THREAD, klass->java_mirror()));
2563 args.push_oop(name_str);
2564 args.push_oop(method_type);
2565 args.push_oop(appendix_box);
2566 JavaValue result(T_OBJECT);
2567 JavaCalls::call_static(&result,
2568 SystemDictionary::MethodHandleNatives_klass(),
2569 vmSymbols::linkMethod_name(),
2570 vmSymbols::linkMethod_signature(),
2571 &args, CHECK_(empty));
2572 Handle mname(THREAD, (oop) result.get_jobject());
2573 (*method_type_result) = method_type;
2574 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2575 }
2576
2577 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2578 // We must ensure that all class loaders everywhere will reach this class, for any client.
2579 // This is a safe bet for public classes in java.lang, such as Object and String.
2580 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2581 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2582 static bool is_always_visible_class(oop mirror) {
2583 Klass* klass = java_lang_Class::as_Klass(mirror);
2584 if (klass->is_objArray_klass()) {
2585 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2586 }
2587 if (klass->is_typeArray_klass()) {
2588 return true; // primitive array
2589 }
2590 assert(klass->is_instance_klass(), "%s", klass->external_name());
2591 return klass->is_public() &&
2592 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2593 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2594 }
2595
2596
2597 // Return the Java mirror (java.lang.Class instance) for a single-character
2598 // descriptor. This result, when available, is the same as produced by the
2599 // heavier API point of the same name that takes a Symbol.
2600 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2601 return java_lang_Class::primitive_mirror(char2type(signature_char));
2602 }
2603
2604 // Find or construct the Java mirror (java.lang.Class instance) for a
2605 // for the given field type signature, as interpreted relative to the
2606 // given class loader. Handles primitives, void, references, arrays,
2607 // and all other reflectable types, except method types.
2608 // N.B. Code in reflection should use this entry point.
2609 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2610 Klass* accessing_klass,
2611 Handle class_loader,
2612 Handle protection_domain,
2613 SignatureStream::FailureMode failure_mode,
2614 TRAPS) {
2615 Handle empty;
2616
2617 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2618 "one or the other, or perhaps neither");
2619
2620 Symbol* type = signature;
2621
2622 // What we have here must be a valid field descriptor,
2623 // and all valid field descriptors are supported.
2624 // Produce the same java.lang.Class that reflection reports.
2625 if (type->utf8_length() == 1) {
2626
2627 // It's a primitive. (Void has a primitive mirror too.)
2628 char ch = (char) type->byte_at(0);
2629 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2630 return Handle(THREAD, find_java_mirror_for_type(ch));
2631
2632 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2633
2634 // It's a reference type.
2635 if (accessing_klass != NULL) {
2636 class_loader = Handle(THREAD, accessing_klass->class_loader());
2637 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2638 }
2639 Klass* constant_type_klass;
2640 if (failure_mode == SignatureStream::ReturnNull) {
2641 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2642 CHECK_(empty));
2643 } else {
2644 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2645 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2646 throw_error, CHECK_(empty));
2647 }
2648 if (constant_type_klass == NULL) {
2649 return Handle(); // report failure this way
2650 }
2651 Handle mirror(THREAD, constant_type_klass->java_mirror());
2652
2653 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2654 if (accessing_klass != NULL) {
2655 Klass* sel_klass = constant_type_klass;
2656 bool fold_type_to_class = true;
2657 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2658 fold_type_to_class, CHECK_(empty));
2659 }
2660
2661 return mirror;
2662
2663 }
2664
2665 // Fall through to an error.
2666 assert(false, "unsupported mirror syntax");
2667 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2668 }
2669
2670
2671 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2672 // signature, as interpreted relative to the given class loader.
2673 // Because of class loader constraints, all method handle usage must be
2674 // consistent with this loader.
2675 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2676 Klass* accessing_klass,
2677 TRAPS) {
2678 Handle empty;
2679 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2680 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2681 int index = invoke_method_table()->hash_to_index(hash);
2682 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2683 if (spe != NULL && spe->method_type() != NULL) {
2684 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2685 return Handle(THREAD, spe->method_type());
2686 } else if (!THREAD->can_call_java()) {
2687 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2688 return Handle(); // do not attempt from within compiler, unless it was cached
2689 }
2690
2691 Handle class_loader, protection_domain;
2692 if (accessing_klass != NULL) {
2693 class_loader = Handle(THREAD, accessing_klass->class_loader());
2694 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2695 }
2696 bool can_be_cached = true;
2697 int npts = ArgumentCount(signature).size();
2698 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2699 int arg = 0;
2700 Handle rt; // the return type from the signature
2701 ResourceMark rm(THREAD);
2702 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2703 oop mirror = NULL;
2704 if (can_be_cached) {
2705 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2706 mirror = ss.as_java_mirror(Handle(), Handle(),
2707 SignatureStream::ReturnNull, CHECK_(empty));
2708 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2709 // Fall back to accessing_klass context.
2710 can_be_cached = false;
2711 }
2712 }
2713 if (!can_be_cached) {
2714 // Resolve, throwing a real error if it doesn't work.
2715 mirror = ss.as_java_mirror(class_loader, protection_domain,
2716 SignatureStream::NCDFError, CHECK_(empty));
2717 }
2718 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2719 if (ss.at_return_type())
2720 rt = Handle(THREAD, mirror);
2721 else
2722 pts->obj_at_put(arg++, mirror);
2723
2724 // Check accessibility.
2725 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2726 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2727 mirror = NULL; // safety
2728 // Emulate ConstantPool::verify_constant_pool_resolve.
2729 bool fold_type_to_class = true;
2730 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2731 fold_type_to_class, CHECK_(empty));
2732 }
2733 }
2734 assert(arg == npts, "");
2735
2736 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2737 JavaCallArguments args(Handle(THREAD, rt()));
2738 args.push_oop(pts);
2739 JavaValue result(T_OBJECT);
2740 JavaCalls::call_static(&result,
2741 SystemDictionary::MethodHandleNatives_klass(),
2742 vmSymbols::findMethodHandleType_name(),
2743 vmSymbols::findMethodHandleType_signature(),
2744 &args, CHECK_(empty));
2745 Handle method_type(THREAD, (oop) result.get_jobject());
2746
2747 if (can_be_cached) {
2748 // We can cache this MethodType inside the JVM.
2749 MutexLocker ml(SystemDictionary_lock, THREAD);
2750 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2751 if (spe == NULL)
2752 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2753 if (spe->method_type() == NULL) {
2754 spe->set_method_type(method_type());
2755 }
2756 }
2757
2758 // report back to the caller with the MethodType
2759 return method_type;
2760 }
2761
2762 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2763 Klass* accessing_klass,
2764 TRAPS) {
2765 Handle empty;
2766 ResourceMark rm(THREAD);
2767 SignatureStream ss(signature, /*is_method=*/ false);
2768 if (!ss.is_done()) {
2769 Handle class_loader, protection_domain;
2770 if (accessing_klass != NULL) {
2771 class_loader = Handle(THREAD, accessing_klass->class_loader());
2772 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2773 }
2774 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2775 ss.next();
2776 if (ss.is_done()) {
2777 return Handle(THREAD, mirror);
2778 }
2779 }
2780 return empty;
2781 }
2782
2783 // Ask Java code to find or construct a method handle constant.
2784 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2785 int ref_kind, //e.g., JVM_REF_invokeVirtual
2786 Klass* callee,
2787 Symbol* name,
2788 Symbol* signature,
2789 TRAPS) {
2790 Handle empty;
2791 if (caller == NULL) {
2792 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2793 }
2794 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2795 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2796
2797 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2798 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2799 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2800 java_lang_invoke_MemberName::set_name (mname(), name_str());
2801 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2802 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2803
2804 if (ref_kind == JVM_REF_invokeVirtual &&
2805 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2806 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2807 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2808 // They are public signature polymorphic methods, but require appendix argument
2809 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2810 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2811 } else {
2812 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2813 }
2814
2815 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2816 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2817
2818 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2819 JavaCallArguments args;
2820 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2821 args.push_int(ref_kind);
2822 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2823 args.push_oop(name_str);
2824 args.push_oop(type);
2825 JavaValue result(T_OBJECT);
2826 JavaCalls::call_static(&result,
2827 SystemDictionary::MethodHandleNatives_klass(),
2828 vmSymbols::linkMethodHandleConstant_name(),
2829 vmSymbols::linkMethodHandleConstant_signature(),
2830 &args, CHECK_(empty));
2831 return Handle(THREAD, (oop) result.get_jobject());
2832 }
2833
2834 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2835 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2836 int condy_index,
2837 Handle bootstrap_specifier,
2838 Symbol* name,
2839 Symbol* type,
2840 TRAPS) {
2841 Handle empty;
2842 Handle bsm, info;
2843 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2844 bsm = bootstrap_specifier;
2845 } else {
2846 assert(bootstrap_specifier->is_objArray(), "");
2847 objArrayOop args = (objArrayOop) bootstrap_specifier();
2848 assert(args->length() == 2, "");
2849 bsm = Handle(THREAD, args->obj_at(0));
2850 info = Handle(THREAD, args->obj_at(1));
2851 }
2852 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2853 "caller must supply a valid BSM");
2854
2855 // This should not happen. JDK code should take care of that.
2856 if (caller == NULL) {
2857 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2858 }
2859
2860 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2861
2862 // Resolve the constant type in the context of the caller class
2863 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2864 CHECK_(empty));
2865
2866 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2867 JavaCallArguments args;
2868 args.push_oop(Handle(THREAD, caller->java_mirror()));
2869 args.push_int(condy_index);
2870 args.push_oop(bsm);
2871 args.push_oop(constant_name);
2872 args.push_oop(type_mirror);
2873 args.push_oop(info);
2874 JavaValue result(T_OBJECT);
2875 JavaCalls::call_static(&result,
2876 SystemDictionary::MethodHandleNatives_klass(),
2877 vmSymbols::linkDynamicConstant_name(),
2878 vmSymbols::linkDynamicConstant_signature(),
2879 &args, CHECK_(empty));
2880
2881 return Handle(THREAD, (oop) result.get_jobject());
2882 }
2883
2884 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2885 // name and signature, as interpreted relative to the given class loader.
2886 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2887 int indy_index,
2888 Handle bootstrap_specifier,
2889 Symbol* name,
2890 Symbol* type,
2891 Handle *appendix_result,
2892 Handle *method_type_result,
2893 TRAPS) {
2894 methodHandle empty;
2895 Handle bsm, info;
2896 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2897 bsm = bootstrap_specifier;
2898 } else {
2899 objArrayOop args = (objArrayOop) bootstrap_specifier();
2900 assert(args->length() == 2, "");
2901 bsm = Handle(THREAD, args->obj_at(0));
2902 info = Handle(THREAD, args->obj_at(1));
2903 }
2904 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2905 "caller must supply a valid BSM");
2906
2907 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2908 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2909
2910 // This should not happen. JDK code should take care of that.
2911 if (caller == NULL || method_type.is_null()) {
2912 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2913 }
2914
2915 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2916 assert(appendix_box->obj_at(0) == NULL, "");
2917
2918 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2919 JavaCallArguments args;
2920 args.push_oop(Handle(THREAD, caller->java_mirror()));
2921 args.push_int(indy_index);
2922 args.push_oop(bsm);
2923 args.push_oop(method_name);
2924 args.push_oop(method_type);
2925 args.push_oop(info);
2926 args.push_oop(appendix_box);
2927 JavaValue result(T_OBJECT);
2928 JavaCalls::call_static(&result,
2929 SystemDictionary::MethodHandleNatives_klass(),
2930 vmSymbols::linkCallSite_name(),
2931 vmSymbols::linkCallSite_signature(),
2932 &args, CHECK_(empty));
2933 Handle mname(THREAD, (oop) result.get_jobject());
2934 (*method_type_result) = method_type;
2935 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2936 }
2937
2938 // Protection domain cache table handling
2939
2940 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2941 return _pd_cache_table->get(protection_domain);
2942 }
2943
2944 #if INCLUDE_CDS
2945 void SystemDictionary::reorder_dictionary_for_sharing() {
2946 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2947 }
2948 #endif
2949
2950 size_t SystemDictionary::count_bytes_for_buckets() {
2951 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2952 }
2953
2954 size_t SystemDictionary::count_bytes_for_table() {
2955 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2956 }
2957
2958 void SystemDictionary::copy_buckets(char* top, char* end) {
2959 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2960 }
2961
2962 void SystemDictionary::copy_table(char* top, char* end) {
2963 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2964 }
2965
2966 // ----------------------------------------------------------------------------
2967 void SystemDictionary::print_shared(outputStream *st) {
2968 shared_dictionary()->print_on(st);
2969 }
2970
2971 void SystemDictionary::print_on(outputStream *st) {
2972 if (shared_dictionary() != NULL) {
2973 st->print_cr("Shared Dictionary");
2974 shared_dictionary()->print_on(st);
2975 st->cr();
2976 }
2977
2978 GCMutexLocker mu(SystemDictionary_lock);
2979
2980 ClassLoaderDataGraph::print_dictionary(st);
2981
2982 // Placeholders
2983 placeholders()->print_on(st);
2984 st->cr();
2985
2986 // loader constraints - print under SD_lock
2987 constraints()->print_on(st);
2988 st->cr();
2989
2990 _pd_cache_table->print_on(st);
2991 st->cr();
2992 }
2993
2994 void SystemDictionary::verify() {
2995 guarantee(constraints() != NULL,
2996 "Verify of loader constraints failed");
2997 guarantee(placeholders()->number_of_entries() >= 0,
2998 "Verify of placeholders failed");
2999
3000 GCMutexLocker mu(SystemDictionary_lock);
3001
3002 // Verify dictionary
3003 ClassLoaderDataGraph::verify_dictionary();
3004
3005 placeholders()->verify();
3006
3007 // Verify constraint table
3008 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3009 constraints()->verify(placeholders());
3010
3011 _pd_cache_table->verify();
3012 }
3013
3014 void SystemDictionary::dump(outputStream *st, bool verbose) {
3015 assert_locked_or_safepoint(SystemDictionary_lock);
3016 if (verbose) {
3017 print_on(st);
3018 } else {
3019 if (shared_dictionary() != NULL) {
3020 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3021 }
3022 ClassLoaderDataGraph::print_dictionary_statistics(st);
3023 placeholders()->print_table_statistics(st, "Placeholder Table");
3024 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3025 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3026 }
3027 }
3028
3029 // Utility for dumping dictionaries.
3030 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3031 DCmdWithParser(output, heap),
3032 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3033 "BOOLEAN", false, "false") {
3034 _dcmdparser.add_dcmd_option(&_verbose);
3035 }
3036
3037 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3038 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3039 _verbose.value());
3040 VMThread::execute(&dumper);
3041 }
3042
3043 int SystemDictionaryDCmd::num_arguments() {
3044 ResourceMark rm;
3045 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3046 if (dcmd != NULL) {
3047 DCmdMark mark(dcmd);
3048 return dcmd->_dcmdparser.num_arguments();
3049 } else {
3050 return 0;
3051 }
3052 }
3053
3054 class CombineDictionariesClosure : public CLDClosure {
3055 private:
3056 Dictionary* _master_dictionary;
3057 public:
3058 CombineDictionariesClosure(Dictionary* master_dictionary) :
3059 _master_dictionary(master_dictionary) {}
3060 void do_cld(ClassLoaderData* cld) {
3061 ResourceMark rm;
3062 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3063 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3064 Dictionary* curr_dictionary = cld->dictionary();
3065 DictionaryEntry* p = curr_dictionary->bucket(i);
3066 while (p != NULL) {
3067 Symbol* name = p->instance_klass()->name();
3068 unsigned int d_hash = _master_dictionary->compute_hash(name);
3069 int d_index = _master_dictionary->hash_to_index(d_hash);
3070 DictionaryEntry* next = p->next();
3071 if (p->literal()->class_loader_data() != cld) {
3072 // This is an initiating class loader entry; don't use it
3073 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3074 curr_dictionary->free_entry(p);
3075 } else {
3076 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3077 curr_dictionary->unlink_entry(p);
3078 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3079 _master_dictionary->add_entry(d_index, p);
3080 }
3081 p = next;
3082 }
3083 *curr_dictionary->bucket_addr(i) = NULL;
3084 }
3085 }
3086 }
3087 };
3088
3089 // Combining platform and system loader dictionaries into boot loader dictionaries.
3090 // During run time, we only have one shared dictionary.
3091 void SystemDictionary::combine_shared_dictionaries() {
3092 assert(DumpSharedSpaces, "dump time only");
3093 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3094 CombineDictionariesClosure cdc(master_dictionary);
3095 ClassLoaderDataGraph::cld_do(&cdc);
3096
3097 // These tables are no longer valid or necessary. Keeping them around will
3098 // cause SystemDictionary::verify() to fail. Let's empty them.
3099 _placeholders = new PlaceholderTable(_placeholder_table_size);
3100 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3101
3102 NOT_PRODUCT(SystemDictionary::verify());
3103 }
3104
3105 // caller needs ResourceMark
3106 const char* SystemDictionary::loader_name(const oop loader) {
3107 return ((loader) == NULL ? "<bootloader>" :
3108 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3109 }
3110
3111 // caller needs ResourceMark
3112 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3113 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3114 SystemDictionary::loader_name(loader_data->class_loader()));
3115 }