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_loadClassInternal = false;
110 bool SystemDictionary::_has_checkPackageAccess = false;
111
112 // lazily initialized klass variables
113 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
114
115 // Default ProtectionDomainCacheSize value
116
117 const int defaultProtectionDomainCacheSize = 1009;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader and PlatformLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 oop SystemDictionary::java_platform_loader() {
128 return _java_platform_loader;
129 }
130
131 void SystemDictionary::compute_java_loaders(TRAPS) {
132 JavaValue result(T_OBJECT);
133 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
134 JavaCalls::call_static(&result,
135 class_loader_klass,
136 vmSymbols::getSystemClassLoader_name(),
137 vmSymbols::void_classloader_signature(),
138 CHECK);
139
140 _java_system_loader = (oop)result.get_jobject();
141
142 JavaCalls::call_static(&result,
143 class_loader_klass,
144 vmSymbols::getPlatformClassLoader_name(),
145 vmSymbols::void_classloader_signature(),
146 CHECK);
147
148 _java_platform_loader = (oop)result.get_jobject();
149
150 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
151 }
152
153 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
154 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
155 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
156 }
157
158 // ----------------------------------------------------------------------------
159 // Parallel class loading check
160
161 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
162 if (class_loader.is_null()) return true;
163 if (AlwaysLockClassLoader) return false;
164 return java_lang_ClassLoader::parallelCapable(class_loader());
165 }
166 // ----------------------------------------------------------------------------
167 // ParallelDefineClass flag does not apply to bootclass loader
168 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
169 if (class_loader.is_null()) return false;
170 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
171 return true;
172 }
173 return false;
174 }
175
176 // Returns true if the passed class loader is the builtin application class loader
177 // or a custom system class loader. A customer system class loader can be
178 // specified via -Djava.system.class.loader.
179 bool SystemDictionary::is_system_class_loader(oop class_loader) {
180 if (class_loader == NULL) {
181 return false;
182 }
183 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
184 class_loader == _java_system_loader);
185 }
186
187 // Returns true if the passed class loader is the platform class loader.
188 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
189 if (class_loader == NULL) {
190 return false;
191 }
192 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
193 }
194
195 // ----------------------------------------------------------------------------
196 // Resolving of classes
197
198 // Forwards to resolve_or_null
199
200 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
201 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
202 if (HAS_PENDING_EXCEPTION || klass == NULL) {
203 // can return a null klass
204 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
205 }
206 return klass;
207 }
208
209 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
210 bool throw_error,
211 Klass* klass, TRAPS) {
212 if (HAS_PENDING_EXCEPTION) {
213 // If we have a pending exception we forward it to the caller, unless throw_error is true,
214 // in which case we have to check whether the pending exception is a ClassNotFoundException,
215 // and if so convert it to a NoClassDefFoundError
216 // And chain the original ClassNotFoundException
217 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
218 ResourceMark rm(THREAD);
219 assert(klass == NULL, "Should not have result with exception pending");
220 Handle e(THREAD, PENDING_EXCEPTION);
221 CLEAR_PENDING_EXCEPTION;
222 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
223 } else {
224 return NULL;
225 }
226 }
227 // Class not found, throw appropriate error or exception depending on value of throw_error
228 if (klass == NULL) {
229 ResourceMark rm(THREAD);
230 if (throw_error) {
231 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
232 } else {
233 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
234 }
235 }
236 return klass;
237 }
238
239
240 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
241 bool throw_error, TRAPS)
242 {
243 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
244 }
245
246
247 // Forwards to resolve_instance_class_or_null
248
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
250 assert(THREAD->can_call_java(),
251 "can not load classes with compiler thread: class=%s, classloader=%s",
252 class_name->as_C_string(),
253 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
254 if (FieldType::is_array(class_name)) {
255 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 } else if (FieldType::is_obj(class_name)) {
257 ResourceMark rm(THREAD);
258 // Ignore wrapping L and ;.
259 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
260 class_name->utf8_length() - 2, CHECK_NULL);
261 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
262 } else {
263 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
264 }
265 }
266
267 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
268 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
269 }
270
271 // Forwards to resolve_instance_class_or_null
272
273 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
274 Handle class_loader,
275 Handle protection_domain,
276 TRAPS) {
277 assert(FieldType::is_array(class_name), "must be array");
278 Klass* k = NULL;
279 FieldArrayInfo fd;
280 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
281 // of this call
282 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
283 if (t == T_OBJECT) {
284 // naked oop "k" is OK here -- we assign back into it
285 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
286 class_loader,
287 protection_domain,
288 CHECK_NULL);
289 if (k != NULL) {
290 k = k->array_klass(fd.dimension(), CHECK_NULL);
291 }
292 } else {
293 k = Universe::typeArrayKlassObj(t);
294 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 return k;
297 }
298
299
300 // Must be called for any super-class or super-interface resolution
301 // during class definition to allow class circularity checking
302 // super-interface callers:
303 // parse_interfaces - for defineClass & jvmtiRedefineClasses
304 // super-class callers:
305 // ClassFileParser - for defineClass & jvmtiRedefineClasses
306 // load_shared_class - while loading a class from shared archive
307 // resolve_instance_class_or_null:
308 // via: handle_parallel_super_load
309 // when resolving a class that has an existing placeholder with
310 // a saved superclass [i.e. a defineClass is currently in progress]
311 // if another thread is trying to resolve the class, it must do
312 // super-class checks on its own thread to catch class circularity
313 // This last call is critical in class circularity checking for cases
314 // where classloading is delegated to different threads and the
315 // classloader lock is released.
316 // Take the case: Base->Super->Base
317 // 1. If thread T1 tries to do a defineClass of class Base
318 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
319 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
320 // so it tries to load Super
321 // 3. If we load the class internally, or user classloader uses same thread
322 // loadClassFromxxx or defineClass via parseClassFile Super ...
323 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
324 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
325 // 3.4 calls resolve_super_or_fail Base
326 // 3.5 finds T1,Base -> throws class circularity
327 //OR 4. If T2 tries to resolve Super via defineClass Super ...
328 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
329 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
330 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
331 // 4.4 finds T2, Super -> throws class circularity
332 // Must be called, even if superclass is null, since this is
333 // where the placeholder entry is created which claims this
334 // thread is loading this class/classloader.
335 // Be careful when modifying this code: once you have run
336 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
337 // you need to find_and_remove it before returning.
338 // So be careful to not exit with a CHECK_ macro betweeen these calls.
339 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
340 Symbol* class_name,
341 Handle class_loader,
342 Handle protection_domain,
343 bool is_superclass,
344 TRAPS) {
345 #if INCLUDE_CDS
346 if (DumpSharedSpaces) {
347 // Special processing for CDS dump time.
348 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
349 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
350 if (k) {
351 return k;
352 }
353 }
354 #endif // INCLUDE_CDS
355
356 // Double-check, if child class is already loaded, just return super-class,interface
357 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
358 // dictionary.
359 // Make sure there's a placeholder for the *child* before resolving.
360 // Used as a claim that this thread is currently loading superclass/classloader
361 // Used here for ClassCircularity checks and also for heap verification
362 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
363 // Must check ClassCircularity before checking if super class is already loaded.
364 //
365 // We might not already have a placeholder if this child_name was
366 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
367 // the name of the class might not be known until the stream is actually
368 // parsed.
369 // Bugs 4643874, 4715493
370
371 ClassLoaderData* loader_data = class_loader_data(class_loader);
372 Dictionary* dictionary = loader_data->dictionary();
373 unsigned int d_hash = dictionary->compute_hash(child_name);
374 unsigned int p_hash = placeholders()->compute_hash(child_name);
375 int p_index = placeholders()->hash_to_index(p_hash);
376 // can't throw error holding a lock
377 bool child_already_loaded = false;
378 bool throw_circularity_error = false;
379 {
380 MutexLocker mu(SystemDictionary_lock, THREAD);
381 Klass* childk = find_class(d_hash, child_name, dictionary);
382 Klass* quicksuperk;
383 // to support // loading: if child done loading, just return superclass
384 // if class_name, & class_loader don't match:
385 // if initial define, SD update will give LinkageError
386 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
387 // so we don't throw an exception here.
388 // see: nsk redefclass014 & java.lang.instrument Instrument032
389 if ((childk != NULL ) && (is_superclass) &&
390 ((quicksuperk = childk->super()) != NULL) &&
391
392 ((quicksuperk->name() == class_name) &&
393 (quicksuperk->class_loader() == class_loader()))) {
394 return quicksuperk;
395 } else {
396 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
397 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
398 throw_circularity_error = true;
399 }
400 }
401 if (!throw_circularity_error) {
402 // Be careful not to exit resolve_super
403 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
404 }
405 }
406 if (throw_circularity_error) {
407 ResourceMark rm(THREAD);
408 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
409 }
410
411 // java.lang.Object should have been found above
412 assert(class_name != NULL, "null super class for resolving");
413 // Resolve the super class or interface, check results on return
414 Klass* superk = SystemDictionary::resolve_or_null(class_name,
415 class_loader,
416 protection_domain,
417 THREAD);
418
419 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
420 // It is no longer necessary to keep the placeholder table alive until update_dictionary
421 // or error. GC used to walk the placeholder table as strong roots.
422 // The instanceKlass is kept alive because the class loader is on the stack,
423 // which keeps the loader_data alive, as well as all instanceKlasses in
424 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
425 {
426 MutexLocker mu(SystemDictionary_lock, THREAD);
427 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
428 SystemDictionary_lock->notify_all();
429 }
430 if (HAS_PENDING_EXCEPTION || superk == NULL) {
431 // can null superk
432 superk = handle_resolution_exception(class_name, true, superk, THREAD);
433 }
434
435 return superk;
436 }
437
438 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
439 Handle class_loader,
440 Handle protection_domain,
441 TRAPS) {
442 if(!has_checkPackageAccess()) return;
443
444 // Now we have to call back to java to check if the initating class has access
445 JavaValue result(T_VOID);
446 LogTarget(Debug, protectiondomain) lt;
447 if (lt.is_enabled()) {
448 ResourceMark rm;
449 // Print out trace information
450 LogStream ls(lt);
451 ls.print_cr("Checking package access");
452 ls.print("class loader: "); class_loader()->print_value_on(&ls);
453 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
454 ls.print(" loading: "); klass->print_value_on(&ls);
455 ls.cr();
456 }
457
458 // This handle and the class_loader handle passed in keeps this class from
459 // being unloaded through several GC points.
460 // The class_loader handle passed in is the initiating loader.
461 Handle mirror(THREAD, klass->java_mirror());
462
463 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
464 JavaCalls::call_special(&result,
465 class_loader,
466 system_loader,
467 vmSymbols::checkPackageAccess_name(),
468 vmSymbols::class_protectiondomain_signature(),
469 mirror,
470 protection_domain,
471 THREAD);
472
473 if (HAS_PENDING_EXCEPTION) {
474 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
475 } else {
476 log_debug(protectiondomain)("granted");
477 }
478
479 if (HAS_PENDING_EXCEPTION) return;
480
481 // If no exception has been thrown, we have validated the protection domain
482 // Insert the protection domain of the initiating class into the set.
483 {
484 ClassLoaderData* loader_data = class_loader_data(class_loader);
485 Dictionary* dictionary = loader_data->dictionary();
486
487 Symbol* kn = klass->name();
488 unsigned int d_hash = dictionary->compute_hash(kn);
489
490 MutexLocker mu(SystemDictionary_lock, THREAD);
491 int d_index = dictionary->hash_to_index(d_hash);
492 dictionary->add_protection_domain(d_index, d_hash, klass,
493 protection_domain, THREAD);
494 }
495 }
496
497 // We only get here if this thread finds that another thread
498 // has already claimed the placeholder token for the current operation,
499 // but that other thread either never owned or gave up the
500 // object lock
501 // Waits on SystemDictionary_lock to indicate placeholder table updated
502 // On return, caller must recheck placeholder table state
503 //
504 // We only get here if
505 // 1) custom classLoader, i.e. not bootstrap classloader
506 // 2) custom classLoader has broken the class loader objectLock
507 // so another thread got here in parallel
508 //
509 // lockObject must be held.
510 // Complicated dance due to lock ordering:
511 // Must first release the classloader object lock to
512 // allow initial definer to complete the class definition
513 // and to avoid deadlock
514 // Reclaim classloader lock object with same original recursion count
515 // Must release SystemDictionary_lock after notify, since
516 // class loader lock must be claimed before SystemDictionary_lock
517 // to prevent deadlocks
518 //
519 // The notify allows applications that did an untimed wait() on
520 // the classloader object lock to not hang.
521 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
522 assert_lock_strong(SystemDictionary_lock);
523
524 bool calledholdinglock
525 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
526 assert(calledholdinglock,"must hold lock for notify");
527 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
528 ObjectSynchronizer::notifyall(lockObject, THREAD);
529 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
530 SystemDictionary_lock->wait();
531 SystemDictionary_lock->unlock();
532 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
533 SystemDictionary_lock->lock();
534 }
535
536 // If the class in is in the placeholder table, class loading is in progress
537 // For cases where the application changes threads to load classes, it
538 // is critical to ClassCircularity detection that we try loading
539 // the superclass on the same thread internally, so we do parallel
540 // super class loading here.
541 // This also is critical in cases where the original thread gets stalled
542 // even in non-circularity situations.
543 // Note: must call resolve_super_or_fail even if null super -
544 // to force placeholder entry creation for this class for circularity detection
545 // Caller must check for pending exception
546 // Returns non-null Klass* if other thread has completed load
547 // and we are done,
548 // If return null Klass* and no pending exception, the caller must load the class
549 InstanceKlass* SystemDictionary::handle_parallel_super_load(
550 Symbol* name, Symbol* superclassname, Handle class_loader,
551 Handle protection_domain, Handle lockObject, TRAPS) {
552
553 ClassLoaderData* loader_data = class_loader_data(class_loader);
554 Dictionary* dictionary = loader_data->dictionary();
555 unsigned int d_hash = dictionary->compute_hash(name);
556 unsigned int p_hash = placeholders()->compute_hash(name);
557 int p_index = placeholders()->hash_to_index(p_hash);
558
559 // superk is not used, resolve_super called for circularity check only
560 // This code is reached in two situations. One if this thread
561 // is loading the same class twice (e.g. ClassCircularity, or
562 // java.lang.instrument).
563 // The second is if another thread started the resolve_super first
564 // and has not yet finished.
565 // In both cases the original caller will clean up the placeholder
566 // entry on error.
567 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
568 superclassname,
569 class_loader,
570 protection_domain,
571 true,
572 CHECK_NULL);
573
574 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
575 // Serial class loaders and bootstrap classloader do wait for superclass loads
576 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
577 MutexLocker mu(SystemDictionary_lock, THREAD);
578 // Check if classloading completed while we were loading superclass or waiting
579 return find_class(d_hash, name, dictionary);
580 }
581
582 // must loop to both handle other placeholder updates
583 // and spurious notifications
584 bool super_load_in_progress = true;
585 PlaceholderEntry* placeholder;
586 while (super_load_in_progress) {
587 MutexLocker mu(SystemDictionary_lock, THREAD);
588 // Check if classloading completed while we were loading superclass or waiting
589 InstanceKlass* check = find_class(d_hash, name, dictionary);
590 if (check != NULL) {
591 // Klass is already loaded, so just return it
592 return check;
593 } else {
594 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
595 if (placeholder && placeholder->super_load_in_progress() ){
596 // We only get here if the application has released the
597 // classloader lock when another thread was in the middle of loading a
598 // superclass/superinterface for this class, and now
599 // this thread is also trying to load this class.
600 // To minimize surprises, the first thread that started to
601 // load a class should be the one to complete the loading
602 // with the classfile it initially expected.
603 // This logic has the current thread wait once it has done
604 // all the superclass/superinterface loading it can, until
605 // the original thread completes the class loading or fails
606 // If it completes we will use the resulting InstanceKlass
607 // which we will find below in the systemDictionary.
608 // We also get here for parallel bootstrap classloader
609 if (class_loader.is_null()) {
610 SystemDictionary_lock->wait();
611 } else {
612 double_lock_wait(lockObject, THREAD);
613 }
614 } else {
615 // If not in SD and not in PH, other thread's load must have failed
616 super_load_in_progress = false;
617 }
618 }
619 }
620 return NULL;
621 }
622
623 static void post_class_load_event(EventClassLoad* event,
624 const InstanceKlass* k,
625 const ClassLoaderData* init_cld) {
626 #if INCLUDE_TRACE
627 assert(event != NULL, "invariant");
628 assert(k != NULL, "invariant");
629 if (event->should_commit()) {
630 event->set_loadedClass(k);
631 event->set_definingClassLoader(k->class_loader_data());
632 event->set_initiatingClassLoader(init_cld);
633 event->commit();
634 }
635 #endif // INCLUDE_TRACE
636 }
637
638 static void class_define_event(InstanceKlass* k,
639 const ClassLoaderData* def_cld) {
640 #if INCLUDE_TRACE
641 EventClassDefine event;
642 if (event.should_commit()) {
643 event.set_definedClass(k);
644 event.set_definingClassLoader(def_cld);
645 event.commit();
646 }
647 #endif // INCLUDE_TRACE
648 }
649
650 // Be careful when modifying this code: once you have run
651 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
652 // you need to find_and_remove it before returning.
653 // So be careful to not exit with a CHECK_ macro betweeen these calls.
654 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
655 Handle class_loader,
656 Handle protection_domain,
657 TRAPS) {
658 assert(name != NULL && !FieldType::is_array(name) &&
659 !FieldType::is_obj(name), "invalid class name");
660
661 EventClassLoad class_load_start_event;
662
663 HandleMark hm(THREAD);
664
665 // Fix for 4474172; see evaluation for more details
666 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
667 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
668 Dictionary* dictionary = loader_data->dictionary();
669 unsigned int d_hash = dictionary->compute_hash(name);
670
671 // Do lookup to see if class already exist and the protection domain
672 // has the right access
673 // This call uses find which checks protection domain already matches
674 // All subsequent calls use find_class, and set has_loaded_class so that
675 // before we return a result we call out to java to check for valid protection domain
676 // to allow returning the Klass* and add it to the pd_set if it is valid
677 {
678 Klass* probe = dictionary->find(d_hash, name, protection_domain);
679 if (probe != NULL) return probe;
680 }
681
682 // Non-bootstrap class loaders will call out to class loader and
683 // define via jvm/jni_DefineClass which will acquire the
684 // class loader object lock to protect against multiple threads
685 // defining the class in parallel by accident.
686 // This lock must be acquired here so the waiter will find
687 // any successful result in the SystemDictionary and not attempt
688 // the define.
689 // ParallelCapable Classloaders and the bootstrap classloader
690 // do not acquire lock here.
691 bool DoObjectLock = true;
692 if (is_parallelCapable(class_loader)) {
693 DoObjectLock = false;
694 }
695
696 unsigned int p_hash = placeholders()->compute_hash(name);
697 int p_index = placeholders()->hash_to_index(p_hash);
698
699 // Class is not in SystemDictionary so we have to do loading.
700 // Make sure we are synchronized on the class loader before we proceed
701 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
702 check_loader_lock_contention(lockObject, THREAD);
703 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
704
705 // Check again (after locking) if class already exist in SystemDictionary
706 bool class_has_been_loaded = false;
707 bool super_load_in_progress = false;
708 bool havesupername = false;
709 InstanceKlass* k = NULL;
710 PlaceholderEntry* placeholder;
711 Symbol* superclassname = NULL;
712
713 {
714 MutexLocker mu(SystemDictionary_lock, THREAD);
715 InstanceKlass* check = find_class(d_hash, name, dictionary);
716 if (check != NULL) {
717 // Klass is already loaded, so just return it
718 class_has_been_loaded = true;
719 k = check;
720 } else {
721 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
722 if (placeholder && placeholder->super_load_in_progress()) {
723 super_load_in_progress = true;
724 if (placeholder->havesupername() == true) {
725 superclassname = placeholder->supername();
726 havesupername = true;
727 }
728 }
729 }
730 }
731
732 // If the class is in the placeholder table, class loading is in progress
733 if (super_load_in_progress && havesupername==true) {
734 k = handle_parallel_super_load(name,
735 superclassname,
736 class_loader,
737 protection_domain,
738 lockObject, THREAD);
739 if (HAS_PENDING_EXCEPTION) {
740 return NULL;
741 }
742 if (k != NULL) {
743 class_has_been_loaded = true;
744 }
745 }
746
747 bool throw_circularity_error = false;
748 if (!class_has_been_loaded) {
749 bool load_instance_added = false;
750
751 // add placeholder entry to record loading instance class
752 // Five cases:
753 // All cases need to prevent modifying bootclasssearchpath
754 // in parallel with a classload of same classname
755 // Redefineclasses uses existence of the placeholder for the duration
756 // of the class load to prevent concurrent redefinition of not completely
757 // defined classes.
758 // case 1. traditional classloaders that rely on the classloader object lock
759 // - no other need for LOAD_INSTANCE
760 // case 2. traditional classloaders that break the classloader object lock
761 // as a deadlock workaround. Detection of this case requires that
762 // this check is done while holding the classloader object lock,
763 // and that lock is still held when calling classloader's loadClass.
764 // For these classloaders, we ensure that the first requestor
765 // completes the load and other requestors wait for completion.
766 // case 3. Bootstrap classloader - don't own objectLocker
767 // This classloader supports parallelism at the classloader level,
768 // but only allows a single load of a class/classloader pair.
769 // No performance benefit and no deadlock issues.
770 // case 4. parallelCapable user level classloaders - without objectLocker
771 // Allow parallel classloading of a class/classloader pair
772
773 {
774 MutexLocker mu(SystemDictionary_lock, THREAD);
775 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
776 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
777 if (oldprobe) {
778 // only need check_seen_thread once, not on each loop
779 // 6341374 java/lang/Instrument with -Xcomp
780 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
781 throw_circularity_error = true;
782 } else {
783 // case 1: traditional: should never see load_in_progress.
784 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
785
786 // case 4: bootstrap classloader: prevent futile classloading,
787 // wait on first requestor
788 if (class_loader.is_null()) {
789 SystemDictionary_lock->wait();
790 } else {
791 // case 2: traditional with broken classloader lock. wait on first
792 // requestor.
793 double_lock_wait(lockObject, THREAD);
794 }
795 // Check if classloading completed while we were waiting
796 InstanceKlass* check = find_class(d_hash, name, dictionary);
797 if (check != NULL) {
798 // Klass is already loaded, so just return it
799 k = check;
800 class_has_been_loaded = true;
801 }
802 // check if other thread failed to load and cleaned up
803 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
804 }
805 }
806 }
807 }
808 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
809 // case 4: parallelCapable: allow competing threads to try
810 // LOAD_INSTANCE in parallel
811
812 if (!throw_circularity_error && !class_has_been_loaded) {
813 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
814 load_instance_added = true;
815 // For class loaders that do not acquire the classloader object lock,
816 // if they did not catch another thread holding LOAD_INSTANCE,
817 // need a check analogous to the acquire ObjectLocker/find_class
818 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
819 // one final check if the load has already completed
820 // class loaders holding the ObjectLock shouldn't find the class here
821 InstanceKlass* check = find_class(d_hash, name, dictionary);
822 if (check != NULL) {
823 // Klass is already loaded, so return it after checking/adding protection domain
824 k = check;
825 class_has_been_loaded = true;
826 }
827 }
828 }
829
830 // must throw error outside of owning lock
831 if (throw_circularity_error) {
832 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
833 ResourceMark rm(THREAD);
834 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
835 }
836
837 if (!class_has_been_loaded) {
838
839 // Do actual loading
840 k = load_instance_class(name, class_loader, THREAD);
841
842 // If they got a linkageError, check if a parallel class load succeeded.
843 // If it did, then for bytecode resolution the specification requires
844 // that we return the same result we did for the other thread, i.e. the
845 // successfully loaded InstanceKlass
846 // Should not get here for classloaders that support parallelism
847 // with the new cleaner mechanism, even with AllowParallelDefineClass
848 // Bootstrap goes through here to allow for an extra guarantee check
849 if ((class_loader.is_null())) {
850 if (k == NULL && HAS_PENDING_EXCEPTION
851 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
852 MutexLocker mu(SystemDictionary_lock, THREAD);
853 InstanceKlass* check = find_class(d_hash, name, dictionary);
854 if (check != NULL) {
855 // Klass is already loaded, so just use it
856 k = check;
857 CLEAR_PENDING_EXCEPTION;
858 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
859 }
860 }
861 }
862
863 // If everything was OK (no exceptions, no null return value), and
864 // class_loader is NOT the defining loader, do a little more bookkeeping.
865 if (!HAS_PENDING_EXCEPTION && k != NULL &&
866 k->class_loader() != class_loader()) {
867
868 check_constraints(d_hash, k, class_loader, false, THREAD);
869
870 // Need to check for a PENDING_EXCEPTION again; check_constraints
871 // can throw and doesn't use the CHECK macro.
872 if (!HAS_PENDING_EXCEPTION) {
873 { // Grabbing the Compile_lock prevents systemDictionary updates
874 // during compilations.
875 MutexLocker mu(Compile_lock, THREAD);
876 update_dictionary(d_hash, p_index, p_hash,
877 k, class_loader, THREAD);
878 }
879
880 if (JvmtiExport::should_post_class_load()) {
881 Thread *thread = THREAD;
882 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
883 JvmtiExport::post_class_load((JavaThread *) thread, k);
884 }
885 }
886 }
887 } // load_instance_class
888
889 if (load_instance_added == true) {
890 // clean up placeholder entries for LOAD_INSTANCE success or error
891 // This brackets the SystemDictionary updates for both defining
892 // and initiating loaders
893 MutexLocker mu(SystemDictionary_lock, THREAD);
894 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
895 SystemDictionary_lock->notify_all();
896 }
897 }
898
899 if (HAS_PENDING_EXCEPTION || k == NULL) {
900 return NULL;
901 }
902
903 post_class_load_event(&class_load_start_event, k, loader_data);
904
905 #ifdef ASSERT
906 {
907 ClassLoaderData* loader_data = k->class_loader_data();
908 MutexLocker mu(SystemDictionary_lock, THREAD);
909 Klass* kk = find_class(name, loader_data);
910 assert(kk == k, "should be present in dictionary");
911 }
912 #endif
913
914 // return if the protection domain in NULL
915 if (protection_domain() == NULL) return k;
916
917 // Check the protection domain has the right access
918 if (dictionary->is_valid_protection_domain(d_hash, name,
919 protection_domain)) {
920 return k;
921 }
922
923 // Verify protection domain. If it fails an exception is thrown
924 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
925
926 return k;
927 }
928
929
930 // This routine does not lock the system dictionary.
931 //
932 // Since readers don't hold a lock, we must make sure that system
933 // dictionary entries are only removed at a safepoint (when only one
934 // thread is running), and are added to in a safe way (all links must
935 // be updated in an MT-safe manner).
936 //
937 // Callers should be aware that an entry could be added just after
938 // _dictionary->bucket(index) is read here, so the caller will not see
939 // the new entry.
940
941 Klass* SystemDictionary::find(Symbol* class_name,
942 Handle class_loader,
943 Handle protection_domain,
944 TRAPS) {
945
946 // The result of this call should be consistent with the result
947 // of the call to resolve_instance_class_or_null().
948 // See evaluation 6790209 and 4474172 for more details.
949 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
950 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
951
952 if (loader_data == NULL) {
953 // If the ClassLoaderData has not been setup,
954 // then the class loader has no entries in the dictionary.
955 return NULL;
956 }
957
958 Dictionary* dictionary = loader_data->dictionary();
959 unsigned int d_hash = dictionary->compute_hash(class_name);
960 return dictionary->find(d_hash, class_name,
961 protection_domain);
962 }
963
964
965 // Look for a loaded instance or array klass by name. Do not do any loading.
966 // return NULL in case of error.
967 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
968 Handle class_loader,
969 Handle protection_domain,
970 TRAPS) {
971 Klass* k = NULL;
972 assert(class_name != NULL, "class name must be non NULL");
973
974 if (FieldType::is_array(class_name)) {
975 // The name refers to an array. Parse the name.
976 // dimension and object_key in FieldArrayInfo are assigned as a
977 // side-effect of this call
978 FieldArrayInfo fd;
979 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
980 if (t != T_OBJECT) {
981 k = Universe::typeArrayKlassObj(t);
982 } else {
983 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
984 }
985 if (k != NULL) {
986 k = k->array_klass_or_null(fd.dimension());
987 }
988 } else {
989 k = find(class_name, class_loader, protection_domain, THREAD);
990 }
991 return k;
992 }
993
994 // Note: this method is much like resolve_from_stream, but
995 // does not publish the classes via the SystemDictionary.
996 // Handles unsafe_DefineAnonymousClass and redefineclasses
997 // RedefinedClasses do not add to the class hierarchy
998 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
999 Handle class_loader,
1000 Handle protection_domain,
1001 ClassFileStream* st,
1002 const InstanceKlass* host_klass,
1003 GrowableArray<Handle>* cp_patches,
1004 TRAPS) {
1005
1006 EventClassLoad class_load_start_event;
1007
1008 ClassLoaderData* loader_data;
1009 if (host_klass != NULL) {
1010 // Create a new CLD for anonymous class, that uses the same class loader
1011 // as the host_klass
1012 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1013 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1014 } else {
1015 loader_data = ClassLoaderData::class_loader_data(class_loader());
1016 }
1017
1018 assert(st != NULL, "invariant");
1019 assert(st->need_verify(), "invariant");
1020
1021 // Parse stream and create a klass.
1022 // Note that we do this even though this klass might
1023 // already be present in the SystemDictionary, otherwise we would not
1024 // throw potential ClassFormatErrors.
1025
1026 InstanceKlass* k = KlassFactory::create_from_stream(st,
1027 class_name,
1028 loader_data,
1029 protection_domain,
1030 host_klass,
1031 cp_patches,
1032 CHECK_NULL);
1033
1034 if (host_klass != NULL && k != NULL) {
1035 // If it's anonymous, initialize it now, since nobody else will.
1036
1037 {
1038 MutexLocker mu_r(Compile_lock, THREAD);
1039
1040 // Add to class hierarchy, initialize vtables, and do possible
1041 // deoptimizations.
1042 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1043
1044 // But, do not add to dictionary.
1045
1046 // compiled code dependencies need to be validated anyway
1047 notice_modification();
1048 }
1049
1050 // Rewrite and patch constant pool here.
1051 k->link_class(CHECK_NULL);
1052 if (cp_patches != NULL) {
1053 k->constants()->patch_resolved_references(cp_patches);
1054 }
1055 k->eager_initialize(CHECK_NULL);
1056
1057 // notify jvmti
1058 if (JvmtiExport::should_post_class_load()) {
1059 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1060 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1061 }
1062
1063 post_class_load_event(&class_load_start_event, k, loader_data);
1064 }
1065 assert(host_klass != NULL || NULL == cp_patches,
1066 "cp_patches only found with host_klass");
1067
1068 return k;
1069 }
1070
1071 // Add a klass to the system from a stream (called by jni_DefineClass and
1072 // JVM_DefineClass).
1073 // Note: class_name can be NULL. In that case we do not know the name of
1074 // the class until we have parsed the stream.
1075
1076 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1077 Handle class_loader,
1078 Handle protection_domain,
1079 ClassFileStream* st,
1080 TRAPS) {
1081 #if INCLUDE_CDS
1082 ResourceMark rm(THREAD);
1083 if (DumpSharedSpaces && !class_loader.is_null() &&
1084 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1085 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1086 // class, which is used by MethodHandles).
1087 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1088 }
1089 #endif
1090
1091 HandleMark hm(THREAD);
1092
1093 // Classloaders that support parallelism, e.g. bootstrap classloader,
1094 // do not acquire lock here
1095 bool DoObjectLock = true;
1096 if (is_parallelCapable(class_loader)) {
1097 DoObjectLock = false;
1098 }
1099
1100 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1101
1102 // Make sure we are synchronized on the class loader before we proceed
1103 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1104 check_loader_lock_contention(lockObject, THREAD);
1105 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1106
1107 assert(st != NULL, "invariant");
1108
1109 // Parse the stream and create a klass.
1110 // Note that we do this even though this klass might
1111 // already be present in the SystemDictionary, otherwise we would not
1112 // throw potential ClassFormatErrors.
1113 InstanceKlass* k = NULL;
1114
1115 #if INCLUDE_CDS
1116 if (!DumpSharedSpaces) {
1117 k = SystemDictionaryShared::lookup_from_stream(class_name,
1118 class_loader,
1119 protection_domain,
1120 st,
1121 CHECK_NULL);
1122 }
1123 #endif
1124
1125 if (k == NULL) {
1126 if (st->buffer() == NULL) {
1127 return NULL;
1128 }
1129 k = KlassFactory::create_from_stream(st,
1130 class_name,
1131 loader_data,
1132 protection_domain,
1133 NULL, // host_klass
1134 NULL, // cp_patches
1135 CHECK_NULL);
1136 }
1137
1138 assert(k != NULL, "no klass created");
1139 Symbol* h_name = k->name();
1140 assert(class_name == NULL || class_name == h_name, "name mismatch");
1141
1142 // Add class just loaded
1143 // If a class loader supports parallel classloading handle parallel define requests
1144 // find_or_define_instance_class may return a different InstanceKlass
1145 if (is_parallelCapable(class_loader)) {
1146 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1147 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1148 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1149 assert(defined_k != NULL, "Should have a klass if there's no exception");
1150 loader_data->add_to_deallocate_list(k);
1151 k = defined_k;
1152 }
1153 } else {
1154 define_instance_class(k, THREAD);
1155 }
1156
1157 // If defining the class throws an exception register 'k' for cleanup.
1158 if (HAS_PENDING_EXCEPTION) {
1159 assert(k != NULL, "Must have an instance klass here!");
1160 loader_data->add_to_deallocate_list(k);
1161 return NULL;
1162 }
1163
1164 // Make sure we have an entry in the SystemDictionary on success
1165 debug_only( {
1166 MutexLocker mu(SystemDictionary_lock, THREAD);
1167
1168 Klass* check = find_class(h_name, k->class_loader_data());
1169 assert(check == k, "should be present in the dictionary");
1170 } );
1171
1172 return k;
1173 }
1174
1175 #if INCLUDE_CDS
1176 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1177 int number_of_entries) {
1178 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1179 "bad shared dictionary size.");
1180 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1181 _shared_dictionary_size, t, number_of_entries);
1182 }
1183
1184
1185 // If there is a shared dictionary, then find the entry for the
1186 // given shared system class, if any.
1187
1188 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1189 if (shared_dictionary() != NULL) {
1190 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1191 int d_index = shared_dictionary()->hash_to_index(d_hash);
1192
1193 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1194 } else {
1195 return NULL;
1196 }
1197 }
1198
1199
1200 // Load a class from the shared spaces (found through the shared system
1201 // dictionary). Force the superclass and all interfaces to be loaded.
1202 // Update the class definition to include sibling classes and no
1203 // subclasses (yet). [Classes in the shared space are not part of the
1204 // object hierarchy until loaded.]
1205
1206 InstanceKlass* SystemDictionary::load_shared_class(
1207 Symbol* class_name, Handle class_loader, TRAPS) {
1208 InstanceKlass* ik = find_shared_class(class_name);
1209 // Make sure we only return the boot class for the NULL classloader.
1210 if (ik != NULL &&
1211 ik->is_shared_boot_class() && class_loader.is_null()) {
1212 Handle protection_domain;
1213 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1214 }
1215 return NULL;
1216 }
1217
1218 // Check if a shared class can be loaded by the specific classloader:
1219 //
1220 // NULL classloader:
1221 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1222 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1223 // be defined in an unnamed module.
1224 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1225 InstanceKlass* ik,
1226 Handle class_loader, TRAPS) {
1227 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1228 "Cannot use sharing if java.base is patched");
1229 ResourceMark rm;
1230 int path_index = ik->shared_classpath_index();
1231 ClassLoaderData* loader_data = class_loader_data(class_loader);
1232 if (path_index < 0) {
1233 // path_index < 0 indicates that the class is intended for a custom loader
1234 // and should not be loaded by boot/platform/app loaders
1235 if (loader_data->is_builtin_class_loader_data()) {
1236 return false;
1237 } else {
1238 return true;
1239 }
1240 }
1241 SharedClassPathEntry* ent =
1242 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1243 if (!Universe::is_module_initialized()) {
1244 assert(ent != NULL && ent->is_modules_image(),
1245 "Loading non-bootstrap classes before the module system is initialized");
1246 assert(class_loader.is_null(), "sanity");
1247 return true;
1248 }
1249 // Get the pkg_entry from the classloader
1250 TempNewSymbol pkg_name = NULL;
1251 PackageEntry* pkg_entry = NULL;
1252 ModuleEntry* mod_entry = NULL;
1253 const char* pkg_string = NULL;
1254 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1255 if (pkg_name != NULL) {
1256 pkg_string = pkg_name->as_C_string();
1257 if (loader_data != NULL) {
1258 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1259 }
1260 if (pkg_entry != NULL) {
1261 mod_entry = pkg_entry->module();
1262 }
1263 }
1264
1265 // If the archived class is from a module that has been patched at runtime,
1266 // the class cannot be loaded from the archive.
1267 if (mod_entry != NULL && mod_entry->is_patched()) {
1268 return false;
1269 }
1270
1271 if (class_loader.is_null()) {
1272 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1273 // The NULL classloader can load archived class originated from the
1274 // "modules" jimage and the -Xbootclasspath/a. For class from the
1275 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1276 // by the NULL classloader.
1277 if (mod_entry != NULL) {
1278 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1279 // ModuleEntry's location agrees with the archived class' origination.
1280 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1281 return true; // Module class from the "module" jimage
1282 }
1283 }
1284
1285 // If the archived class is not from the "module" jimage, the class can be
1286 // loaded by the NULL classloader if
1287 //
1288 // 1. the class is from the unamed package
1289 // 2. or, the class is not from a module defined in the NULL classloader
1290 // 3. or, the class is from an unamed module
1291 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1292 // the class is from the -Xbootclasspath/a
1293 if (pkg_string == NULL ||
1294 pkg_entry == NULL ||
1295 pkg_entry->in_unnamed_module()) {
1296 assert(mod_entry == NULL ||
1297 mod_entry == loader_data->unnamed_module(),
1298 "the unnamed module is not defined in the classloader");
1299 return true;
1300 }
1301 }
1302 return false;
1303 } else {
1304 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1305 ik, class_loader, pkg_string, pkg_name,
1306 pkg_entry, mod_entry, CHECK_(false));
1307 return res;
1308 }
1309 }
1310
1311 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1312 Handle class_loader,
1313 Handle protection_domain, TRAPS) {
1314
1315 if (ik != NULL) {
1316 Symbol* class_name = ik->name();
1317
1318 bool visible = is_shared_class_visible(
1319 class_name, ik, class_loader, CHECK_NULL);
1320 if (!visible) {
1321 return NULL;
1322 }
1323
1324 // Resolve the superclass and interfaces. They must be the same
1325 // as in dump time, because the layout of <ik> depends on
1326 // the specific layout of ik->super() and ik->local_interfaces().
1327 //
1328 // If unexpected superclass or interfaces are found, we cannot
1329 // load <ik> from the shared archive.
1330
1331 if (ik->super() != NULL) {
1332 Symbol* cn = ik->super()->name();
1333 Klass *s = resolve_super_or_fail(class_name, cn,
1334 class_loader, protection_domain, true, CHECK_NULL);
1335 if (s != ik->super()) {
1336 // The dynamically resolved super 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(s->is_shared(), "must be");
1341 }
1342 }
1343
1344 Array<Klass*>* interfaces = ik->local_interfaces();
1345 int num_interfaces = interfaces->length();
1346 for (int index = 0; index < num_interfaces; index++) {
1347 Klass* k = interfaces->at(index);
1348 Symbol* name = k->name();
1349 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1350 if (k != i) {
1351 // The dynamically resolved interface class is not the same as the one we used during dump time,
1352 // so we cannot use ik.
1353 return NULL;
1354 } else {
1355 assert(i->is_shared(), "must be");
1356 }
1357 }
1358
1359 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1360 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1361 if (new_ik != NULL) {
1362 // The class is changed by CFLH. Return the new class. The shared class is
1363 // not used.
1364 return new_ik;
1365 }
1366
1367 // Adjust methods to recover missing data. They need addresses for
1368 // interpreter entry points and their default native method address
1369 // must be reset.
1370
1371 // Updating methods must be done under a lock so multiple
1372 // threads don't update these in parallel
1373 //
1374 // Shared classes are all currently loaded by either the bootstrap or
1375 // internal parallel class loaders, so this will never cause a deadlock
1376 // on a custom class loader lock.
1377
1378 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1379 {
1380 HandleMark hm(THREAD);
1381 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1382 check_loader_lock_contention(lockObject, THREAD);
1383 ObjectLocker ol(lockObject, THREAD, true);
1384 // prohibited package check assumes all classes loaded from archive call
1385 // restore_unshareable_info which calls ik->set_package()
1386 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1387 }
1388
1389 ik->print_class_load_logging(loader_data, NULL, NULL);
1390
1391 // For boot loader, ensure that GetSystemPackage knows that a class in this
1392 // package was loaded.
1393 if (class_loader.is_null()) {
1394 int path_index = ik->shared_classpath_index();
1395 ResourceMark rm;
1396 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1397 }
1398
1399 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1400 // Only dump the classes that can be stored into CDS archive
1401 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1402 ResourceMark rm(THREAD);
1403 classlist_file->print_cr("%s", ik->name()->as_C_string());
1404 classlist_file->flush();
1405 }
1406 }
1407
1408 // notify a class loaded from shared object
1409 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1410 }
1411
1412 ik->set_has_passed_fingerprint_check(false);
1413 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1414 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1415 uint64_t cds_fp = ik->get_stored_fingerprint();
1416 if (aot_fp != 0 && aot_fp == cds_fp) {
1417 // This class matches with a class saved in an AOT library
1418 ik->set_has_passed_fingerprint_check(true);
1419 } else {
1420 ResourceMark rm;
1421 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1422 }
1423 }
1424 return ik;
1425 }
1426
1427 void SystemDictionary::clear_invoke_method_table() {
1428 SymbolPropertyEntry* spe = NULL;
1429 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1430 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1431 while (p != NULL) {
1432 spe = p;
1433 p = p->next();
1434 _invoke_method_table->free_entry(spe);
1435 }
1436 }
1437 }
1438 #endif // INCLUDE_CDS
1439
1440 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1441
1442 if (class_loader.is_null()) {
1443 ResourceMark rm;
1444 PackageEntry* pkg_entry = NULL;
1445 bool search_only_bootloader_append = false;
1446 ClassLoaderData *loader_data = class_loader_data(class_loader);
1447
1448 // Find the package in the boot loader's package entry table.
1449 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1450 if (pkg_name != NULL) {
1451 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1452 }
1453
1454 // Prior to attempting to load the class, enforce the boot loader's
1455 // visibility boundaries.
1456 if (!Universe::is_module_initialized()) {
1457 // During bootstrapping, prior to module initialization, any
1458 // class attempting to be loaded must be checked against the
1459 // java.base packages in the boot loader's PackageEntryTable.
1460 // No class outside of java.base is allowed to be loaded during
1461 // this bootstrapping window.
1462 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1463 // Class is either in the unnamed package or in
1464 // a named package within the unnamed module. Either
1465 // case is outside of java.base, do not attempt to
1466 // load the class post java.base definition. If
1467 // java.base has not been defined, let the class load
1468 // and its package will be checked later by
1469 // ModuleEntryTable::verify_javabase_packages.
1470 if (ModuleEntryTable::javabase_defined()) {
1471 return NULL;
1472 }
1473 } else {
1474 // Check that the class' package is defined within java.base.
1475 ModuleEntry* mod_entry = pkg_entry->module();
1476 Symbol* mod_entry_name = mod_entry->name();
1477 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1478 return NULL;
1479 }
1480 }
1481 } else {
1482 // After the module system has been initialized, check if the class'
1483 // package is in a module defined to the boot loader.
1484 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1485 // Class is either in the unnamed package, in a named package
1486 // within a module not defined to the boot loader or in a
1487 // a named package within the unnamed module. In all cases,
1488 // limit visibility to search for the class only in the boot
1489 // loader's append path.
1490 search_only_bootloader_append = true;
1491 }
1492 }
1493
1494 // Prior to bootstrapping's module initialization, never load a class outside
1495 // of the boot loader's module path
1496 assert(Universe::is_module_initialized() ||
1497 !search_only_bootloader_append,
1498 "Attempt to load a class outside of boot loader's module path");
1499
1500 // Search the shared system dictionary for classes preloaded into the
1501 // shared spaces.
1502 InstanceKlass* k = NULL;
1503 {
1504 #if INCLUDE_CDS
1505 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1506 k = load_shared_class(class_name, class_loader, THREAD);
1507 #endif
1508 }
1509
1510 if (k == NULL) {
1511 // Use VM class loader
1512 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1513 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1514 }
1515
1516 // find_or_define_instance_class may return a different InstanceKlass
1517 if (k != NULL) {
1518 InstanceKlass* defined_k =
1519 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1520 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1521 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1522 assert(defined_k != NULL, "Should have a klass if there's no exception");
1523 loader_data->add_to_deallocate_list(k);
1524 k = defined_k;
1525 } else if (HAS_PENDING_EXCEPTION) {
1526 loader_data->add_to_deallocate_list(k);
1527 return NULL;
1528 }
1529 }
1530 return k;
1531 } else {
1532 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1533 ResourceMark rm(THREAD);
1534
1535 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1536 JavaThread* jt = (JavaThread*) THREAD;
1537
1538 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1539 ClassLoader::perf_app_classload_selftime(),
1540 ClassLoader::perf_app_classload_count(),
1541 jt->get_thread_stat()->perf_recursion_counts_addr(),
1542 jt->get_thread_stat()->perf_timers_addr(),
1543 PerfClassTraceTime::CLASS_LOAD);
1544
1545 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1546 // Translate to external class name format, i.e., convert '/' chars to '.'
1547 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1548
1549 JavaValue result(T_OBJECT);
1550
1551 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1552
1553 // Call public unsynchronized loadClass(String) directly for all class loaders
1554 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1555 // acquire a class-name based lock rather than the class loader object lock.
1556 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1557 // so the call to loadClassInternal() was not required.
1558 JavaCalls::call_virtual(&result,
1559 class_loader,
1560 spec_klass,
1561 vmSymbols::loadClass_name(),
1562 vmSymbols::string_class_signature(),
1563 string,
1564 CHECK_NULL);
1565
1566 assert(result.get_type() == T_OBJECT, "just checking");
1567 oop obj = (oop) result.get_jobject();
1568
1569 // Primitive classes return null since forName() can not be
1570 // used to obtain any of the Class objects representing primitives or void
1571 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1572 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1573 // For user defined Java class loaders, check that the name returned is
1574 // the same as that requested. This check is done for the bootstrap
1575 // loader when parsing the class file.
1576 if (class_name == k->name()) {
1577 return k;
1578 }
1579 }
1580 // Class is not found or has the wrong name, return NULL
1581 return NULL;
1582 }
1583 }
1584
1585 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1586
1587 HandleMark hm(THREAD);
1588 ClassLoaderData* loader_data = k->class_loader_data();
1589 Handle class_loader_h(THREAD, loader_data->class_loader());
1590
1591 // for bootstrap and other parallel classloaders don't acquire lock,
1592 // use placeholder token
1593 // If a parallelCapable class loader calls define_instance_class instead of
1594 // find_or_define_instance_class to get here, we have a timing
1595 // hole with systemDictionary updates and check_constraints
1596 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1597 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1598 compute_loader_lock_object(class_loader_h, THREAD)),
1599 "define called without lock");
1600 }
1601
1602 // Check class-loading constraints. Throw exception if violation is detected.
1603 // Grabs and releases SystemDictionary_lock
1604 // The check_constraints/find_class call and update_dictionary sequence
1605 // must be "atomic" for a specific class/classloader pair so we never
1606 // define two different instanceKlasses for that class/classloader pair.
1607 // Existing classloaders will call define_instance_class with the
1608 // classloader lock held
1609 // Parallel classloaders will call find_or_define_instance_class
1610 // which will require a token to perform the define class
1611 Symbol* name_h = k->name();
1612 Dictionary* dictionary = loader_data->dictionary();
1613 unsigned int d_hash = dictionary->compute_hash(name_h);
1614 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1615
1616 // Register class just loaded with class loader (placed in Vector)
1617 // Note we do this before updating the dictionary, as this can
1618 // fail with an OutOfMemoryError (if it does, we will *not* put this
1619 // class in the dictionary and will not update the class hierarchy).
1620 // JVMTI FollowReferences needs to find the classes this way.
1621 if (k->class_loader() != NULL) {
1622 methodHandle m(THREAD, Universe::loader_addClass_method());
1623 JavaValue result(T_VOID);
1624 JavaCallArguments args(class_loader_h);
1625 args.push_oop(Handle(THREAD, k->java_mirror()));
1626 JavaCalls::call(&result, m, &args, CHECK);
1627 }
1628
1629 // Add the new class. We need recompile lock during update of CHA.
1630 {
1631 unsigned int p_hash = placeholders()->compute_hash(name_h);
1632 int p_index = placeholders()->hash_to_index(p_hash);
1633
1634 MutexLocker mu_r(Compile_lock, THREAD);
1635
1636 // Add to class hierarchy, initialize vtables, and do possible
1637 // deoptimizations.
1638 add_to_hierarchy(k, CHECK); // No exception, but can block
1639
1640 // Add to systemDictionary - so other classes can see it.
1641 // Grabs and releases SystemDictionary_lock
1642 update_dictionary(d_hash, p_index, p_hash,
1643 k, class_loader_h, THREAD);
1644 }
1645 k->eager_initialize(THREAD);
1646
1647 // notify jvmti
1648 if (JvmtiExport::should_post_class_load()) {
1649 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1650 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1651
1652 }
1653 class_define_event(k, loader_data);
1654 }
1655
1656 // Support parallel classloading
1657 // All parallel class loaders, including bootstrap classloader
1658 // lock a placeholder entry for this class/class_loader pair
1659 // to allow parallel defines of different classes for this class loader
1660 // With AllowParallelDefine flag==true, in case they do not synchronize around
1661 // FindLoadedClass/DefineClass, calls, we check for parallel
1662 // loading for them, wait if a defineClass is in progress
1663 // and return the initial requestor's results
1664 // This flag does not apply to the bootstrap classloader.
1665 // With AllowParallelDefine flag==false, call through to define_instance_class
1666 // which will throw LinkageError: duplicate class definition.
1667 // False is the requested default.
1668 // For better performance, the class loaders should synchronize
1669 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1670 // potentially waste time reading and parsing the bytestream.
1671 // Note: VM callers should ensure consistency of k/class_name,class_loader
1672 // Be careful when modifying this code: once you have run
1673 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1674 // you need to find_and_remove it before returning.
1675 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1676 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1677 InstanceKlass* k, TRAPS) {
1678
1679 Symbol* name_h = k->name(); // passed in class_name may be null
1680 ClassLoaderData* loader_data = class_loader_data(class_loader);
1681 Dictionary* dictionary = loader_data->dictionary();
1682
1683 unsigned int d_hash = dictionary->compute_hash(name_h);
1684
1685 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1686 unsigned int p_hash = placeholders()->compute_hash(name_h);
1687 int p_index = placeholders()->hash_to_index(p_hash);
1688 PlaceholderEntry* probe;
1689
1690 {
1691 MutexLocker mu(SystemDictionary_lock, THREAD);
1692 // First check if class already defined
1693 if (is_parallelDefine(class_loader)) {
1694 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1695 if (check != NULL) {
1696 return check;
1697 }
1698 }
1699
1700 // Acquire define token for this class/classloader
1701 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1702 // Wait if another thread defining in parallel
1703 // All threads wait - even those that will throw duplicate class: otherwise
1704 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1705 // if other thread has not finished updating dictionary
1706 while (probe->definer() != NULL) {
1707 SystemDictionary_lock->wait();
1708 }
1709 // Only special cases allow parallel defines and can use other thread's results
1710 // Other cases fall through, and may run into duplicate defines
1711 // caught by finding an entry in the SystemDictionary
1712 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1713 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1714 SystemDictionary_lock->notify_all();
1715 #ifdef ASSERT
1716 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1717 assert(check != NULL, "definer missed recording success");
1718 #endif
1719 return probe->instance_klass();
1720 } else {
1721 // This thread will define the class (even if earlier thread tried and had an error)
1722 probe->set_definer(THREAD);
1723 }
1724 }
1725
1726 define_instance_class(k, THREAD);
1727
1728 Handle linkage_exception = Handle(); // null handle
1729
1730 // definer must notify any waiting threads
1731 {
1732 MutexLocker mu(SystemDictionary_lock, THREAD);
1733 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1734 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1735 if (probe != NULL) {
1736 if (HAS_PENDING_EXCEPTION) {
1737 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1738 CLEAR_PENDING_EXCEPTION;
1739 } else {
1740 probe->set_instance_klass(k);
1741 }
1742 probe->set_definer(NULL);
1743 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1744 SystemDictionary_lock->notify_all();
1745 }
1746 }
1747
1748 // Can't throw exception while holding lock due to rank ordering
1749 if (linkage_exception() != NULL) {
1750 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1751 }
1752
1753 return k;
1754 }
1755
1756 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1757 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1758 if (class_loader.is_null()) {
1759 return Handle(THREAD, _system_loader_lock_obj);
1760 } else {
1761 return class_loader;
1762 }
1763 }
1764
1765 // This method is added to check how often we have to wait to grab loader
1766 // lock. The results are being recorded in the performance counters defined in
1767 // ClassLoader::_sync_systemLoaderLockContentionRate and
1768 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1769 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1770 if (!UsePerfData) {
1771 return;
1772 }
1773
1774 assert(!loader_lock.is_null(), "NULL lock object");
1775
1776 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1777 == ObjectSynchronizer::owner_other) {
1778 // contention will likely happen, so increment the corresponding
1779 // contention counter.
1780 if (loader_lock() == _system_loader_lock_obj) {
1781 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1782 } else {
1783 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1784 }
1785 }
1786 }
1787
1788 // ----------------------------------------------------------------------------
1789 // Lookup
1790
1791 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1792 Symbol* class_name,
1793 Dictionary* dictionary) {
1794 assert_locked_or_safepoint(SystemDictionary_lock);
1795 int index = dictionary->hash_to_index(hash);
1796 return dictionary->find_class(index, hash, class_name);
1797 }
1798
1799
1800 // Basic find on classes in the midst of being loaded
1801 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1802 ClassLoaderData* loader_data) {
1803 assert_locked_or_safepoint(SystemDictionary_lock);
1804 unsigned int p_hash = placeholders()->compute_hash(class_name);
1805 int p_index = placeholders()->hash_to_index(p_hash);
1806 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1807 }
1808
1809
1810 // Used for assertions and verification only
1811 // Precalculating the hash and index is an optimization because there are many lookups
1812 // before adding the class.
1813 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1814 assert_locked_or_safepoint(SystemDictionary_lock);
1815 #ifndef ASSERT
1816 guarantee(VerifyBeforeGC ||
1817 VerifyDuringGC ||
1818 VerifyBeforeExit ||
1819 VerifyDuringStartup ||
1820 VerifyAfterGC, "too expensive");
1821 #endif
1822
1823 Dictionary* dictionary = loader_data->dictionary();
1824 unsigned int d_hash = dictionary->compute_hash(class_name);
1825 return find_class(d_hash, class_name, dictionary);
1826 }
1827
1828
1829 // ----------------------------------------------------------------------------
1830 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1831 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1832 // before a new class is used.
1833
1834 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1835 assert(k != NULL, "just checking");
1836 assert_locked_or_safepoint(Compile_lock);
1837
1838 // Link into hierachy. Make sure the vtables are initialized before linking into
1839 k->append_to_sibling_list(); // add to superklass/sibling list
1840 k->process_interfaces(THREAD); // handle all "implements" declarations
1841 k->set_init_state(InstanceKlass::loaded);
1842 // Now flush all code that depended on old class hierarchy.
1843 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1844 // Also, first reinitialize vtable because it may have gotten out of synch
1845 // while the new class wasn't connected to the class hierarchy.
1846 CodeCache::flush_dependents_on(k);
1847 }
1848
1849 // ----------------------------------------------------------------------------
1850 // GC support
1851
1852 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1853 roots_oops_do(blk, NULL);
1854 }
1855
1856
1857 #ifdef ASSERT
1858 class VerifySDReachableAndLiveClosure : public OopClosure {
1859 private:
1860 BoolObjectClosure* _is_alive;
1861
1862 template <class T> void do_oop_work(T* p) {
1863 oop obj = oopDesc::load_decode_heap_oop(p);
1864 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1865 }
1866
1867 public:
1868 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1869
1870 virtual void do_oop(oop* p) { do_oop_work(p); }
1871 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1872 };
1873 #endif
1874
1875 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1876 // Note: anonymous classes are not in the SD.
1877 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1878 GCTimer* gc_timer,
1879 bool do_cleaning) {
1880
1881
1882 bool unloading_occurred;
1883 {
1884 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1885
1886 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1887 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1888 do_cleaning);
1889 }
1890
1891 if (unloading_occurred) {
1892 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1893 constraints()->purge_loader_constraints();
1894 resolution_errors()->purge_resolution_errors();
1895 }
1896
1897 {
1898 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1899 // Oops referenced by the protection domain cache table may get unreachable independently
1900 // of the class loader (eg. cached protection domain oops). So we need to
1901 // explicitly unlink them here.
1902 _pd_cache_table->unlink(is_alive);
1903
1904 #ifdef ASSERT
1905 VerifySDReachableAndLiveClosure cl(is_alive);
1906 _pd_cache_table->oops_do(&cl);
1907 #endif
1908 }
1909
1910 if (do_cleaning) {
1911 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1912 ResolvedMethodTable::unlink(is_alive);
1913 }
1914
1915 return unloading_occurred;
1916 }
1917
1918 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1919 strong->do_oop(&_java_system_loader);
1920 strong->do_oop(&_java_platform_loader);
1921 strong->do_oop(&_system_loader_lock_obj);
1922 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1923
1924 // Do strong roots marking if the closures are the same.
1925 if (strong == weak || !ClassUnloading) {
1926 // Only the protection domain oops contain references into the heap. Iterate
1927 // over all of them.
1928 _pd_cache_table->oops_do(strong);
1929 } else {
1930 if (weak != NULL) {
1931 _pd_cache_table->oops_do(weak);
1932 }
1933 }
1934
1935 // Visit extra methods
1936 invoke_method_table()->oops_do(strong);
1937
1938 if (weak != NULL) {
1939 ResolvedMethodTable::oops_do(weak);
1940 }
1941 }
1942
1943 void SystemDictionary::oops_do(OopClosure* f) {
1944 f->do_oop(&_java_system_loader);
1945 f->do_oop(&_java_platform_loader);
1946 f->do_oop(&_system_loader_lock_obj);
1947 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1948
1949 // Only the protection domain oops contain references into the heap. Iterate
1950 // over all of them.
1951 _pd_cache_table->oops_do(f);
1952
1953 // Visit extra methods
1954 invoke_method_table()->oops_do(f);
1955
1956 ResolvedMethodTable::oops_do(f);
1957 }
1958
1959 // CDS: scan and relocate all classes in the system dictionary.
1960 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1961 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1962 }
1963
1964 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1965 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1966 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1967 it->push(well_known_klass_addr((WKID)id));
1968 }
1969 }
1970
1971 void SystemDictionary::methods_do(void f(Method*)) {
1972 // Walk methods in loaded classes
1973 ClassLoaderDataGraph::methods_do(f);
1974 // Walk method handle intrinsics
1975 invoke_method_table()->methods_do(f);
1976 }
1977
1978 class RemoveClassesClosure : public CLDClosure {
1979 public:
1980 void do_cld(ClassLoaderData* cld) {
1981 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1982 cld->dictionary()->remove_classes_in_error_state();
1983 }
1984 }
1985 };
1986
1987 void SystemDictionary::remove_classes_in_error_state() {
1988 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1989 RemoveClassesClosure rcc;
1990 ClassLoaderDataGraph::cld_do(&rcc);
1991 }
1992
1993 // ----------------------------------------------------------------------------
1994 // Lazily load klasses
1995
1996 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1997 // if multiple threads calling this function, only one thread will load
1998 // the class. The other threads will find the loaded version once the
1999 // class is loaded.
2000 Klass* aos = _abstract_ownable_synchronizer_klass;
2001 if (aos == NULL) {
2002 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2003 // Force a fence to prevent any read before the write completes
2004 OrderAccess::fence();
2005 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2006 }
2007 }
2008
2009 // ----------------------------------------------------------------------------
2010 // Initialization
2011
2012 void SystemDictionary::initialize(TRAPS) {
2013 // Allocate arrays
2014 _placeholders = new PlaceholderTable(_placeholder_table_size);
2015 _number_of_modifications = 0;
2016 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2017 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2018 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2019 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2020
2021 // Allocate private object used as system class loader lock
2022 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2023 // Initialize basic classes
2024 initialize_preloaded_classes(CHECK);
2025 }
2026
2027 // Compact table of directions on the initialization of klasses:
2028 static const short wk_init_info[] = {
2029 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2030 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2031 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2032 | (int)SystemDictionary::option ),
2033 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2034 #undef WK_KLASS_INIT_INFO
2035 0
2036 };
2037
2038 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2039 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2040 int info = wk_init_info[id - FIRST_WKID];
2041 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2042 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2043 InstanceKlass** klassp = &_well_known_klasses[id];
2044
2045 bool must_load;
2046 #if INCLUDE_JVMCI
2047 if (EnableJVMCI) {
2048 // If JVMCI is enabled we require its classes to be found.
2049 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2050 } else
2051 #endif
2052 {
2053 must_load = (init_opt < SystemDictionary::Opt);
2054 }
2055
2056 if ((*klassp) == NULL) {
2057 Klass* k;
2058 if (must_load) {
2059 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2060 } else {
2061 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2062 }
2063 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2064 }
2065 return ((*klassp) != NULL);
2066 }
2067
2068 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2069 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2070 for (int id = (int)start_id; id < (int)limit_id; id++) {
2071 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2072 int info = wk_init_info[id - FIRST_WKID];
2073 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2074 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2075
2076 initialize_wk_klass((WKID)id, opt, CHECK);
2077 }
2078
2079 // move the starting value forward to the limit:
2080 start_id = limit_id;
2081 }
2082
2083 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2084 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2085
2086 // Create the ModuleEntry for java.base. This call needs to be done here,
2087 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2088 ClassLoader::classLoader_init2(CHECK);
2089
2090 // Preload commonly used klasses
2091 WKID scan = FIRST_WKID;
2092 // first do Object, then String, Class
2093 #if INCLUDE_CDS
2094 if (UseSharedSpaces) {
2095 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2096 // Initialize the constant pool for the Object_class
2097 Object_klass()->constants()->restore_unshareable_info(CHECK);
2098 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2099 } else
2100 #endif
2101 {
2102 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2103 }
2104
2105 // Calculate offsets for String and Class classes since they are loaded and
2106 // can be used after this point.
2107 java_lang_String::compute_offsets();
2108 java_lang_Class::compute_offsets();
2109
2110 // Fixup mirrors for classes loaded before java.lang.Class.
2111 // These calls iterate over the objects currently in the perm gen
2112 // so calling them at this point is matters (not before when there
2113 // are fewer objects and not later after there are more objects
2114 // in the perm gen.
2115 Universe::initialize_basic_type_mirrors(CHECK);
2116 Universe::fixup_mirrors(CHECK);
2117
2118 // do a bunch more:
2119 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2120
2121 // Preload ref klasses and set reference types
2122 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2123 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2124
2125 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2126 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2127 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2128 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2129 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2130
2131 // JSR 292 classes
2132 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2133 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2134 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2135 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2136 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2137
2138 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2139 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2140 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2141 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2142 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2143 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2144 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2145 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2146 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2147 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2148
2149 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2150 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2151 _has_loadClassInternal = (method != NULL);
2152 }
2153 { // Compute whether we should use checkPackageAccess or NOT
2154 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2155 _has_checkPackageAccess = (method != NULL);
2156 }
2157 }
2158
2159 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2160 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2161 BasicType SystemDictionary::box_klass_type(Klass* k) {
2162 assert(k != NULL, "");
2163 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2164 if (_box_klasses[i] == k)
2165 return (BasicType)i;
2166 }
2167 return T_OBJECT;
2168 }
2169
2170 // Constraints on class loaders. The details of the algorithm can be
2171 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2172 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2173 // that the dictionary needs to maintain a set of contraints that
2174 // must be satisfied by all classes in the dictionary.
2175 // if defining is true, then LinkageError if already in dictionary
2176 // if initiating loader, then ok if InstanceKlass matches existing entry
2177
2178 void SystemDictionary::check_constraints(unsigned int d_hash,
2179 InstanceKlass* k,
2180 Handle class_loader, bool defining,
2181 TRAPS) {
2182 const char *linkage_error1 = NULL;
2183 const char *linkage_error2 = NULL;
2184 {
2185 Symbol* name = k->name();
2186 ClassLoaderData *loader_data = class_loader_data(class_loader);
2187
2188 MutexLocker mu(SystemDictionary_lock, THREAD);
2189
2190 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2191 if (check != NULL) {
2192 // if different InstanceKlass - duplicate class definition,
2193 // else - ok, class loaded by a different thread in parallel,
2194 // we should only have found it if it was done loading and ok to use
2195 // dictionary only holds instance classes, placeholders
2196 // also holds array classes
2197
2198 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2199 if ((defining == true) || (k != check)) {
2200 linkage_error1 = "loader (instance of ";
2201 linkage_error2 = "): attempted duplicate class definition for name: \"";
2202 } else {
2203 return;
2204 }
2205 }
2206
2207 #ifdef ASSERT
2208 Symbol* ph_check = find_placeholder(name, loader_data);
2209 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2210 #endif
2211
2212 if (linkage_error1 == NULL) {
2213 if (constraints()->check_or_update(k, class_loader, name) == false) {
2214 linkage_error1 = "loader constraint violation: loader (instance of ";
2215 linkage_error2 = ") previously initiated loading for a different type with name \"";
2216 }
2217 }
2218 }
2219
2220 // Throw error now if needed (cannot throw while holding
2221 // SystemDictionary_lock because of rank ordering)
2222
2223 if (linkage_error1) {
2224 ResourceMark rm(THREAD);
2225 const char* class_loader_name = loader_name(class_loader());
2226 char* type_name = k->name()->as_C_string();
2227 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2228 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2229 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2230 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2231 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2232 }
2233 }
2234
2235
2236 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2237 // have been called.
2238 void SystemDictionary::update_dictionary(unsigned int d_hash,
2239 int p_index, unsigned int p_hash,
2240 InstanceKlass* k,
2241 Handle class_loader,
2242 TRAPS) {
2243 // Compile_lock prevents systemDictionary updates during compilations
2244 assert_locked_or_safepoint(Compile_lock);
2245 Symbol* name = k->name();
2246 ClassLoaderData *loader_data = class_loader_data(class_loader);
2247
2248 {
2249 MutexLocker mu1(SystemDictionary_lock, THREAD);
2250
2251 // See whether biased locking is enabled and if so set it for this
2252 // klass.
2253 // Note that this must be done past the last potential blocking
2254 // point / safepoint. We enable biased locking lazily using a
2255 // VM_Operation to iterate the SystemDictionary and installing the
2256 // biasable mark word into each InstanceKlass's prototype header.
2257 // To avoid race conditions where we accidentally miss enabling the
2258 // optimization for one class in the process of being added to the
2259 // dictionary, we must not safepoint after the test of
2260 // BiasedLocking::enabled().
2261 if (UseBiasedLocking && BiasedLocking::enabled()) {
2262 // Set biased locking bit for all loaded classes; it will be
2263 // cleared if revocation occurs too often for this type
2264 // NOTE that we must only do this when the class is initally
2265 // defined, not each time it is referenced from a new class loader
2266 if (k->class_loader() == class_loader()) {
2267 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2268 }
2269 }
2270
2271 // Make a new dictionary entry.
2272 Dictionary* dictionary = loader_data->dictionary();
2273 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2274 if (sd_check == NULL) {
2275 dictionary->add_klass(d_hash, name, k);
2276 notice_modification();
2277 }
2278 #ifdef ASSERT
2279 sd_check = find_class(d_hash, name, dictionary);
2280 assert (sd_check != NULL, "should have entry in dictionary");
2281 // Note: there may be a placeholder entry: for circularity testing
2282 // or for parallel defines
2283 #endif
2284 SystemDictionary_lock->notify_all();
2285 }
2286 }
2287
2288
2289 // Try to find a class name using the loader constraints. The
2290 // loader constraints might know about a class that isn't fully loaded
2291 // yet and these will be ignored.
2292 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2293 Symbol* class_name, Handle class_loader, TRAPS) {
2294
2295 // First see if it has been loaded directly.
2296 // Force the protection domain to be null. (This removes protection checks.)
2297 Handle no_protection_domain;
2298 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2299 no_protection_domain, CHECK_NULL);
2300 if (klass != NULL)
2301 return klass;
2302
2303 // Now look to see if it has been loaded elsewhere, and is subject to
2304 // a loader constraint that would require this loader to return the
2305 // klass that is already loaded.
2306 if (FieldType::is_array(class_name)) {
2307 // For array classes, their Klass*s are not kept in the
2308 // constraint table. The element Klass*s are.
2309 FieldArrayInfo fd;
2310 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2311 if (t != T_OBJECT) {
2312 klass = Universe::typeArrayKlassObj(t);
2313 } else {
2314 MutexLocker mu(SystemDictionary_lock, THREAD);
2315 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2316 }
2317 // If element class already loaded, allocate array klass
2318 if (klass != NULL) {
2319 klass = klass->array_klass_or_null(fd.dimension());
2320 }
2321 } else {
2322 MutexLocker mu(SystemDictionary_lock, THREAD);
2323 // Non-array classes are easy: simply check the constraint table.
2324 klass = constraints()->find_constrained_klass(class_name, class_loader);
2325 }
2326
2327 return klass;
2328 }
2329
2330
2331 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2332 Handle class_loader1,
2333 Handle class_loader2,
2334 Thread* THREAD) {
2335 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2336 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2337
2338 Symbol* constraint_name = NULL;
2339 if (!FieldType::is_array(class_name)) {
2340 constraint_name = class_name;
2341 } else {
2342 // For array classes, their Klass*s are not kept in the
2343 // constraint table. The element classes are.
2344 FieldArrayInfo fd;
2345 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2346 // primitive types always pass
2347 if (t != T_OBJECT) {
2348 return true;
2349 } else {
2350 constraint_name = fd.object_key();
2351 }
2352 }
2353
2354 Dictionary* dictionary1 = loader_data1->dictionary();
2355 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2356
2357 Dictionary* dictionary2 = loader_data2->dictionary();
2358 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2359
2360 {
2361 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2362 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2363 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2364 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2365 klass2, class_loader2);
2366 }
2367 }
2368
2369 // Add entry to resolution error table to record the error when the first
2370 // attempt to resolve a reference to a class has failed.
2371 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2372 Symbol* error, Symbol* message) {
2373 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2374 int index = resolution_errors()->hash_to_index(hash);
2375 {
2376 MutexLocker ml(SystemDictionary_lock, Thread::current());
2377 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2378 }
2379 }
2380
2381 // Delete a resolution error for RedefineClasses for a constant pool is going away
2382 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2383 resolution_errors()->delete_entry(pool);
2384 }
2385
2386 // Lookup resolution error table. Returns error if found, otherwise NULL.
2387 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2388 Symbol** message) {
2389 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2390 int index = resolution_errors()->hash_to_index(hash);
2391 {
2392 MutexLocker ml(SystemDictionary_lock, Thread::current());
2393 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2394 if (entry != NULL) {
2395 *message = entry->message();
2396 return entry->error();
2397 } else {
2398 return NULL;
2399 }
2400 }
2401 }
2402
2403
2404 // Signature constraints ensure that callers and callees agree about
2405 // the meaning of type names in their signatures. This routine is the
2406 // intake for constraints. It collects them from several places:
2407 //
2408 // * LinkResolver::resolve_method (if check_access is true) requires
2409 // that the resolving class (the caller) and the defining class of
2410 // the resolved method (the callee) agree on each type in the
2411 // method's signature.
2412 //
2413 // * LinkResolver::resolve_interface_method performs exactly the same
2414 // checks.
2415 //
2416 // * LinkResolver::resolve_field requires that the constant pool
2417 // attempting to link to a field agree with the field's defining
2418 // class about the type of the field signature.
2419 //
2420 // * klassVtable::initialize_vtable requires that, when a class
2421 // overrides a vtable entry allocated by a superclass, that the
2422 // overriding method (i.e., the callee) agree with the superclass
2423 // on each type in the method's signature.
2424 //
2425 // * klassItable::initialize_itable requires that, when a class fills
2426 // in its itables, for each non-abstract method installed in an
2427 // itable, the method (i.e., the callee) agree with the interface
2428 // on each type in the method's signature.
2429 //
2430 // All those methods have a boolean (check_access, checkconstraints)
2431 // which turns off the checks. This is used from specialized contexts
2432 // such as bootstrapping, dumping, and debugging.
2433 //
2434 // No direct constraint is placed between the class and its
2435 // supertypes. Constraints are only placed along linked relations
2436 // between callers and callees. When a method overrides or implements
2437 // an abstract method in a supertype (superclass or interface), the
2438 // constraints are placed as if the supertype were the caller to the
2439 // overriding method. (This works well, since callers to the
2440 // supertype have already established agreement between themselves and
2441 // the supertype.) As a result of all this, a class can disagree with
2442 // its supertype about the meaning of a type name, as long as that
2443 // class neither calls a relevant method of the supertype, nor is
2444 // called (perhaps via an override) from the supertype.
2445 //
2446 //
2447 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2448 //
2449 // Make sure all class components (including arrays) in the given
2450 // signature will be resolved to the same class in both loaders.
2451 // Returns the name of the type that failed a loader constraint check, or
2452 // NULL if no constraint failed. No exception except OOME is thrown.
2453 // Arrays are not added to the loader constraint table, their elements are.
2454 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2455 Handle loader1, Handle loader2,
2456 bool is_method, TRAPS) {
2457 // Nothing to do if loaders are the same.
2458 if (loader1() == loader2()) {
2459 return NULL;
2460 }
2461
2462 SignatureStream sig_strm(signature, is_method);
2463 while (!sig_strm.is_done()) {
2464 if (sig_strm.is_object()) {
2465 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2466 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2467 return sig;
2468 }
2469 }
2470 sig_strm.next();
2471 }
2472 return NULL;
2473 }
2474
2475
2476 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2477 Symbol* signature,
2478 TRAPS) {
2479 methodHandle empty;
2480 assert(MethodHandles::is_signature_polymorphic(iid) &&
2481 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2482 iid != vmIntrinsics::_invokeGeneric,
2483 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2484
2485 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2486 int index = invoke_method_table()->hash_to_index(hash);
2487 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2488 methodHandle m;
2489 if (spe == NULL || spe->method() == NULL) {
2490 spe = NULL;
2491 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2492 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2493 if (!Arguments::is_interpreter_only()) {
2494 // Generate a compiled form of the MH intrinsic.
2495 AdapterHandlerLibrary::create_native_wrapper(m);
2496 // Check if have the compiled code.
2497 if (!m->has_compiled_code()) {
2498 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2499 "Out of space in CodeCache for method handle intrinsic", empty);
2500 }
2501 }
2502 // Now grab the lock. We might have to throw away the new method,
2503 // if a racing thread has managed to install one at the same time.
2504 {
2505 MutexLocker ml(SystemDictionary_lock, THREAD);
2506 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2507 if (spe == NULL)
2508 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2509 if (spe->method() == NULL)
2510 spe->set_method(m());
2511 }
2512 }
2513
2514 assert(spe != NULL && spe->method() != NULL, "");
2515 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2516 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2517 "MH intrinsic invariant");
2518 return spe->method();
2519 }
2520
2521 // Helper for unpacking the return value from linkMethod and linkCallSite.
2522 static methodHandle unpack_method_and_appendix(Handle mname,
2523 Klass* accessing_klass,
2524 objArrayHandle appendix_box,
2525 Handle* appendix_result,
2526 TRAPS) {
2527 methodHandle empty;
2528 if (mname.not_null()) {
2529 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2530 if (m != NULL) {
2531 oop appendix = appendix_box->obj_at(0);
2532 if (TraceMethodHandles) {
2533 #ifndef PRODUCT
2534 ttyLocker ttyl;
2535 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2536 m->print();
2537 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2538 tty->cr();
2539 #endif //PRODUCT
2540 }
2541 (*appendix_result) = Handle(THREAD, appendix);
2542 // the target is stored in the cpCache and if a reference to this
2543 // MethodName is dropped we need a way to make sure the
2544 // class_loader containing this method is kept alive.
2545 // FIXME: the appendix might also preserve this dependency.
2546 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2547 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2548 return methodHandle(THREAD, m);
2549 }
2550 }
2551 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2552 return empty;
2553 }
2554
2555 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2556 Symbol* name,
2557 Symbol* signature,
2558 Klass* accessing_klass,
2559 Handle *appendix_result,
2560 Handle *method_type_result,
2561 TRAPS) {
2562 methodHandle empty;
2563 assert(THREAD->can_call_java() ,"");
2564 Handle method_type =
2565 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2566
2567 int ref_kind = JVM_REF_invokeVirtual;
2568 oop name_oop = StringTable::intern(name, CHECK_(empty));
2569 Handle name_str (THREAD, name_oop);
2570 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2571 assert(appendix_box->obj_at(0) == NULL, "");
2572
2573 // This should not happen. JDK code should take care of that.
2574 if (accessing_klass == NULL || method_type.is_null()) {
2575 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2576 }
2577
2578 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2579 JavaCallArguments args;
2580 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2581 args.push_int(ref_kind);
2582 args.push_oop(Handle(THREAD, klass->java_mirror()));
2583 args.push_oop(name_str);
2584 args.push_oop(method_type);
2585 args.push_oop(appendix_box);
2586 JavaValue result(T_OBJECT);
2587 JavaCalls::call_static(&result,
2588 SystemDictionary::MethodHandleNatives_klass(),
2589 vmSymbols::linkMethod_name(),
2590 vmSymbols::linkMethod_signature(),
2591 &args, CHECK_(empty));
2592 Handle mname(THREAD, (oop) result.get_jobject());
2593 (*method_type_result) = method_type;
2594 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2595 }
2596
2597 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2598 // We must ensure that all class loaders everywhere will reach this class, for any client.
2599 // This is a safe bet for public classes in java.lang, such as Object and String.
2600 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2601 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2602 static bool is_always_visible_class(oop mirror) {
2603 Klass* klass = java_lang_Class::as_Klass(mirror);
2604 if (klass->is_objArray_klass()) {
2605 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2606 }
2607 if (klass->is_typeArray_klass()) {
2608 return true; // primitive array
2609 }
2610 assert(klass->is_instance_klass(), "%s", klass->external_name());
2611 return klass->is_public() &&
2612 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2613 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2614 }
2615
2616
2617 // Return the Java mirror (java.lang.Class instance) for a single-character
2618 // descriptor. This result, when available, is the same as produced by the
2619 // heavier API point of the same name that takes a Symbol.
2620 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2621 return java_lang_Class::primitive_mirror(char2type(signature_char));
2622 }
2623
2624 // Find or construct the Java mirror (java.lang.Class instance) for a
2625 // for the given field type signature, as interpreted relative to the
2626 // given class loader. Handles primitives, void, references, arrays,
2627 // and all other reflectable types, except method types.
2628 // N.B. Code in reflection should use this entry point.
2629 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2630 Klass* accessing_klass,
2631 Handle class_loader,
2632 Handle protection_domain,
2633 SignatureStream::FailureMode failure_mode,
2634 TRAPS) {
2635 Handle empty;
2636
2637 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2638 "one or the other, or perhaps neither");
2639
2640 Symbol* type = signature;
2641
2642 // What we have here must be a valid field descriptor,
2643 // and all valid field descriptors are supported.
2644 // Produce the same java.lang.Class that reflection reports.
2645 if (type->utf8_length() == 1) {
2646
2647 // It's a primitive. (Void has a primitive mirror too.)
2648 char ch = (char) type->byte_at(0);
2649 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2650 return Handle(THREAD, find_java_mirror_for_type(ch));
2651
2652 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2653
2654 // It's a reference type.
2655 if (accessing_klass != NULL) {
2656 class_loader = Handle(THREAD, accessing_klass->class_loader());
2657 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2658 }
2659 Klass* constant_type_klass;
2660 if (failure_mode == SignatureStream::ReturnNull) {
2661 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2662 CHECK_(empty));
2663 } else {
2664 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2665 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2666 throw_error, CHECK_(empty));
2667 }
2668 if (constant_type_klass == NULL) {
2669 return Handle(); // report failure this way
2670 }
2671 Handle mirror(THREAD, constant_type_klass->java_mirror());
2672
2673 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2674 if (accessing_klass != NULL) {
2675 Klass* sel_klass = constant_type_klass;
2676 bool fold_type_to_class = true;
2677 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2678 fold_type_to_class, CHECK_(empty));
2679 }
2680
2681 return mirror;
2682
2683 }
2684
2685 // Fall through to an error.
2686 assert(false, "unsupported mirror syntax");
2687 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2688 }
2689
2690
2691 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2692 // signature, as interpreted relative to the given class loader.
2693 // Because of class loader constraints, all method handle usage must be
2694 // consistent with this loader.
2695 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2696 Klass* accessing_klass,
2697 TRAPS) {
2698 Handle empty;
2699 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2700 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2701 int index = invoke_method_table()->hash_to_index(hash);
2702 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2703 if (spe != NULL && spe->method_type() != NULL) {
2704 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2705 return Handle(THREAD, spe->method_type());
2706 } else if (!THREAD->can_call_java()) {
2707 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2708 return Handle(); // do not attempt from within compiler, unless it was cached
2709 }
2710
2711 Handle class_loader, protection_domain;
2712 if (accessing_klass != NULL) {
2713 class_loader = Handle(THREAD, accessing_klass->class_loader());
2714 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2715 }
2716 bool can_be_cached = true;
2717 int npts = ArgumentCount(signature).size();
2718 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2719 int arg = 0;
2720 Handle rt; // the return type from the signature
2721 ResourceMark rm(THREAD);
2722 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2723 oop mirror = NULL;
2724 if (can_be_cached) {
2725 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2726 mirror = ss.as_java_mirror(Handle(), Handle(),
2727 SignatureStream::ReturnNull, CHECK_(empty));
2728 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2729 // Fall back to accessing_klass context.
2730 can_be_cached = false;
2731 }
2732 }
2733 if (!can_be_cached) {
2734 // Resolve, throwing a real error if it doesn't work.
2735 mirror = ss.as_java_mirror(class_loader, protection_domain,
2736 SignatureStream::NCDFError, CHECK_(empty));
2737 }
2738 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2739 if (ss.at_return_type())
2740 rt = Handle(THREAD, mirror);
2741 else
2742 pts->obj_at_put(arg++, mirror);
2743
2744 // Check accessibility.
2745 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2746 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2747 mirror = NULL; // safety
2748 // Emulate ConstantPool::verify_constant_pool_resolve.
2749 bool fold_type_to_class = true;
2750 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2751 fold_type_to_class, CHECK_(empty));
2752 }
2753 }
2754 assert(arg == npts, "");
2755
2756 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2757 JavaCallArguments args(Handle(THREAD, rt()));
2758 args.push_oop(pts);
2759 JavaValue result(T_OBJECT);
2760 JavaCalls::call_static(&result,
2761 SystemDictionary::MethodHandleNatives_klass(),
2762 vmSymbols::findMethodHandleType_name(),
2763 vmSymbols::findMethodHandleType_signature(),
2764 &args, CHECK_(empty));
2765 Handle method_type(THREAD, (oop) result.get_jobject());
2766
2767 if (can_be_cached) {
2768 // We can cache this MethodType inside the JVM.
2769 MutexLocker ml(SystemDictionary_lock, THREAD);
2770 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2771 if (spe == NULL)
2772 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2773 if (spe->method_type() == NULL) {
2774 spe->set_method_type(method_type());
2775 }
2776 }
2777
2778 // report back to the caller with the MethodType
2779 return method_type;
2780 }
2781
2782 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2783 Klass* accessing_klass,
2784 TRAPS) {
2785 Handle empty;
2786 ResourceMark rm(THREAD);
2787 SignatureStream ss(signature, /*is_method=*/ false);
2788 if (!ss.is_done()) {
2789 Handle class_loader, protection_domain;
2790 if (accessing_klass != NULL) {
2791 class_loader = Handle(THREAD, accessing_klass->class_loader());
2792 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2793 }
2794 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2795 ss.next();
2796 if (ss.is_done()) {
2797 return Handle(THREAD, mirror);
2798 }
2799 }
2800 return empty;
2801 }
2802
2803 // Ask Java code to find or construct a method handle constant.
2804 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2805 int ref_kind, //e.g., JVM_REF_invokeVirtual
2806 Klass* callee,
2807 Symbol* name,
2808 Symbol* signature,
2809 TRAPS) {
2810 Handle empty;
2811 if (caller == NULL) {
2812 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2813 }
2814 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2815 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2816
2817 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2818 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2819 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2820 java_lang_invoke_MemberName::set_name (mname(), name_str());
2821 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2822 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2823
2824 if (ref_kind == JVM_REF_invokeVirtual &&
2825 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2826 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2827 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2828 // They are public signature polymorphic methods, but require appendix argument
2829 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2830 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2831 } else {
2832 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2833 }
2834
2835 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2836 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2837
2838 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2839 JavaCallArguments args;
2840 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2841 args.push_int(ref_kind);
2842 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2843 args.push_oop(name_str);
2844 args.push_oop(type);
2845 JavaValue result(T_OBJECT);
2846 JavaCalls::call_static(&result,
2847 SystemDictionary::MethodHandleNatives_klass(),
2848 vmSymbols::linkMethodHandleConstant_name(),
2849 vmSymbols::linkMethodHandleConstant_signature(),
2850 &args, CHECK_(empty));
2851 return Handle(THREAD, (oop) result.get_jobject());
2852 }
2853
2854 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2855 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2856 int condy_index,
2857 Handle bootstrap_specifier,
2858 Symbol* name,
2859 Symbol* type,
2860 TRAPS) {
2861 Handle empty;
2862 Handle bsm, info;
2863 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2864 bsm = bootstrap_specifier;
2865 } else {
2866 assert(bootstrap_specifier->is_objArray(), "");
2867 objArrayOop args = (objArrayOop) bootstrap_specifier();
2868 assert(args->length() == 2, "");
2869 bsm = Handle(THREAD, args->obj_at(0));
2870 info = Handle(THREAD, args->obj_at(1));
2871 }
2872 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2873 "caller must supply a valid BSM");
2874
2875 // This should not happen. JDK code should take care of that.
2876 if (caller == NULL) {
2877 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2878 }
2879
2880 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2881
2882 // Resolve the constant type in the context of the caller class
2883 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2884 CHECK_(empty));
2885
2886 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2887 JavaCallArguments args;
2888 args.push_oop(Handle(THREAD, caller->java_mirror()));
2889 args.push_int(condy_index);
2890 args.push_oop(bsm);
2891 args.push_oop(constant_name);
2892 args.push_oop(type_mirror);
2893 args.push_oop(info);
2894 JavaValue result(T_OBJECT);
2895 JavaCalls::call_static(&result,
2896 SystemDictionary::MethodHandleNatives_klass(),
2897 vmSymbols::linkDynamicConstant_name(),
2898 vmSymbols::linkDynamicConstant_signature(),
2899 &args, CHECK_(empty));
2900
2901 return Handle(THREAD, (oop) result.get_jobject());
2902 }
2903
2904 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2905 // name and signature, as interpreted relative to the given class loader.
2906 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2907 int indy_index,
2908 Handle bootstrap_specifier,
2909 Symbol* name,
2910 Symbol* type,
2911 Handle *appendix_result,
2912 Handle *method_type_result,
2913 TRAPS) {
2914 methodHandle empty;
2915 Handle bsm, info;
2916 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2917 bsm = bootstrap_specifier;
2918 } else {
2919 objArrayOop args = (objArrayOop) bootstrap_specifier();
2920 assert(args->length() == 2, "");
2921 bsm = Handle(THREAD, args->obj_at(0));
2922 info = Handle(THREAD, args->obj_at(1));
2923 }
2924 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2925 "caller must supply a valid BSM");
2926
2927 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2928 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2929
2930 // This should not happen. JDK code should take care of that.
2931 if (caller == NULL || method_type.is_null()) {
2932 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2933 }
2934
2935 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2936 assert(appendix_box->obj_at(0) == NULL, "");
2937
2938 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2939 JavaCallArguments args;
2940 args.push_oop(Handle(THREAD, caller->java_mirror()));
2941 args.push_int(indy_index);
2942 args.push_oop(bsm);
2943 args.push_oop(method_name);
2944 args.push_oop(method_type);
2945 args.push_oop(info);
2946 args.push_oop(appendix_box);
2947 JavaValue result(T_OBJECT);
2948 JavaCalls::call_static(&result,
2949 SystemDictionary::MethodHandleNatives_klass(),
2950 vmSymbols::linkCallSite_name(),
2951 vmSymbols::linkCallSite_signature(),
2952 &args, CHECK_(empty));
2953 Handle mname(THREAD, (oop) result.get_jobject());
2954 (*method_type_result) = method_type;
2955 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2956 }
2957
2958 // Protection domain cache table handling
2959
2960 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2961 return _pd_cache_table->get(protection_domain);
2962 }
2963
2964 #if INCLUDE_CDS
2965 void SystemDictionary::reorder_dictionary_for_sharing() {
2966 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2967 }
2968 #endif
2969
2970 size_t SystemDictionary::count_bytes_for_buckets() {
2971 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2972 }
2973
2974 size_t SystemDictionary::count_bytes_for_table() {
2975 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2976 }
2977
2978 void SystemDictionary::copy_buckets(char* top, char* end) {
2979 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2980 }
2981
2982 void SystemDictionary::copy_table(char* top, char* end) {
2983 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2984 }
2985
2986 // ----------------------------------------------------------------------------
2987 void SystemDictionary::print_shared(outputStream *st) {
2988 shared_dictionary()->print_on(st);
2989 }
2990
2991 void SystemDictionary::print_on(outputStream *st) {
2992 if (shared_dictionary() != NULL) {
2993 st->print_cr("Shared Dictionary");
2994 shared_dictionary()->print_on(st);
2995 st->cr();
2996 }
2997
2998 GCMutexLocker mu(SystemDictionary_lock);
2999
3000 ClassLoaderDataGraph::print_dictionary(st);
3001
3002 // Placeholders
3003 placeholders()->print_on(st);
3004 st->cr();
3005
3006 // loader constraints - print under SD_lock
3007 constraints()->print_on(st);
3008 st->cr();
3009
3010 _pd_cache_table->print_on(st);
3011 st->cr();
3012 }
3013
3014 void SystemDictionary::verify() {
3015 guarantee(constraints() != NULL,
3016 "Verify of loader constraints failed");
3017 guarantee(placeholders()->number_of_entries() >= 0,
3018 "Verify of placeholders failed");
3019
3020 GCMutexLocker mu(SystemDictionary_lock);
3021
3022 // Verify dictionary
3023 ClassLoaderDataGraph::verify_dictionary();
3024
3025 placeholders()->verify();
3026
3027 // Verify constraint table
3028 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3029 constraints()->verify(placeholders());
3030
3031 _pd_cache_table->verify();
3032 }
3033
3034 void SystemDictionary::dump(outputStream *st, bool verbose) {
3035 assert_locked_or_safepoint(SystemDictionary_lock);
3036 if (verbose) {
3037 print_on(st);
3038 } else {
3039 if (shared_dictionary() != NULL) {
3040 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3041 }
3042 ClassLoaderDataGraph::print_dictionary_statistics(st);
3043 placeholders()->print_table_statistics(st, "Placeholder Table");
3044 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3045 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3046 }
3047 }
3048
3049 // Utility for dumping dictionaries.
3050 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3051 DCmdWithParser(output, heap),
3052 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3053 "BOOLEAN", false, "false") {
3054 _dcmdparser.add_dcmd_option(&_verbose);
3055 }
3056
3057 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3058 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3059 _verbose.value());
3060 VMThread::execute(&dumper);
3061 }
3062
3063 int SystemDictionaryDCmd::num_arguments() {
3064 ResourceMark rm;
3065 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3066 if (dcmd != NULL) {
3067 DCmdMark mark(dcmd);
3068 return dcmd->_dcmdparser.num_arguments();
3069 } else {
3070 return 0;
3071 }
3072 }
3073
3074 class CombineDictionariesClosure : public CLDClosure {
3075 private:
3076 Dictionary* _master_dictionary;
3077 public:
3078 CombineDictionariesClosure(Dictionary* master_dictionary) :
3079 _master_dictionary(master_dictionary) {}
3080 void do_cld(ClassLoaderData* cld) {
3081 ResourceMark rm;
3082 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3083 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3084 Dictionary* curr_dictionary = cld->dictionary();
3085 DictionaryEntry* p = curr_dictionary->bucket(i);
3086 while (p != NULL) {
3087 Symbol* name = p->instance_klass()->name();
3088 unsigned int d_hash = _master_dictionary->compute_hash(name);
3089 int d_index = _master_dictionary->hash_to_index(d_hash);
3090 DictionaryEntry* next = p->next();
3091 if (p->literal()->class_loader_data() != cld) {
3092 // This is an initiating class loader entry; don't use it
3093 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3094 curr_dictionary->free_entry(p);
3095 } else {
3096 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3097 curr_dictionary->unlink_entry(p);
3098 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3099 _master_dictionary->add_entry(d_index, p);
3100 }
3101 p = next;
3102 }
3103 *curr_dictionary->bucket_addr(i) = NULL;
3104 }
3105 }
3106 }
3107 };
3108
3109 // Combining platform and system loader dictionaries into boot loader dictionaries.
3110 // During run time, we only have one shared dictionary.
3111 void SystemDictionary::combine_shared_dictionaries() {
3112 assert(DumpSharedSpaces, "dump time only");
3113 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3114 CombineDictionariesClosure cdc(master_dictionary);
3115 ClassLoaderDataGraph::cld_do(&cdc);
3116
3117 // These tables are no longer valid or necessary. Keeping them around will
3118 // cause SystemDictionary::verify() to fail. Let's empty them.
3119 _placeholders = new PlaceholderTable(_placeholder_table_size);
3120 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3121
3122 NOT_PRODUCT(SystemDictionary::verify());
3123 }
3124
3125 // caller needs ResourceMark
3126 const char* SystemDictionary::loader_name(const oop loader) {
3127 return ((loader) == NULL ? "<bootloader>" :
3128 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3129 }
3130
3131 // caller needs ResourceMark
3132 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3133 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3134 SystemDictionary::loader_name(loader_data->class_loader()));
3135 }