1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/protectionDomainCache.hpp"
39 #include "classfile/resolutionErrors.hpp"
40 #include "classfile/stringTable.hpp"
41 #include "classfile/systemDictionary.hpp"
42 #include "classfile/vmSymbols.hpp"
43 #include "code/codeCache.hpp"
44 #include "compiler/compileBroker.hpp"
45 #include "gc/shared/gcLocker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "interpreter/bytecodeStream.hpp"
48 #include "interpreter/interpreter.hpp"
49 #include "logging/log.hpp"
50 #include "logging/logStream.hpp"
51 #include "memory/filemap.hpp"
52 #include "memory/metaspaceClosure.hpp"
53 #include "memory/oopFactory.hpp"
54 #include "memory/resourceArea.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/instanceRefKlass.hpp"
57 #include "oops/klass.inline.hpp"
58 #include "oops/methodData.hpp"
59 #include "oops/objArrayKlass.hpp"
60 #include "oops/objArrayOop.inline.hpp"
61 #include "oops/oop.inline.hpp"
62 #include "oops/symbol.hpp"
63 #include "oops/typeArrayKlass.hpp"
64 #include "prims/jvm.h"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/biasedLocking.hpp"
70 #include "runtime/fieldType.hpp"
71 #include "runtime/handles.inline.hpp"
72 #include "runtime/java.hpp"
73 #include "runtime/javaCalls.hpp"
74 #include "runtime/mutexLocker.hpp"
75 #include "runtime/orderAccess.inline.hpp"
76 #include "runtime/os.hpp"
77 #include "runtime/signature.hpp"
78 #include "services/classLoadingService.hpp"
79 #include "services/diagnosticCommand.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/traceMacros.hpp"
82 #include "utilities/macros.hpp"
83 #include "utilities/ticks.hpp"
84 #if INCLUDE_CDS
85 #include "classfile/sharedClassUtil.hpp"
86 #include "classfile/systemDictionaryShared.hpp"
87 #endif
88 #if INCLUDE_JVMCI
89 #include "jvmci/jvmciRuntime.hpp"
90 #endif
91 #if INCLUDE_TRACE
92 #include "trace/tracing.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 Dictionary* SystemDictionary::_shared_dictionary = NULL;
97 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
98 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
99 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
100 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
101
102 int SystemDictionary::_number_of_modifications = 0;
103 oop SystemDictionary::_system_loader_lock_obj = NULL;
104
105 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
106 = { NULL /*, NULL...*/ };
107
108 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
109
110 oop SystemDictionary::_java_system_loader = NULL;
111
112 bool SystemDictionary::_has_loadClassInternal = false;
113 bool SystemDictionary::_has_checkPackageAccess = false;
114
115 // lazily initialized klass variables
116 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
117
118 // Default ProtectionDomainCacheSize value
119
120 const int defaultProtectionDomainCacheSize = 1009;
121
122
123 // ----------------------------------------------------------------------------
124 // Java-level SystemLoader
125
126 oop SystemDictionary::java_system_loader() {
127 return _java_system_loader;
128 }
129
130 void SystemDictionary::compute_java_system_loader(TRAPS) {
131 Klass* system_klass = WK_KLASS(ClassLoader_klass);
132 JavaValue result(T_OBJECT);
133 JavaCalls::call_static(&result,
134 WK_KLASS(ClassLoader_klass),
135 vmSymbols::getSystemClassLoader_name(),
136 vmSymbols::void_classloader_signature(),
137 CHECK);
138
139 _java_system_loader = (oop)result.get_jobject();
140
141 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
142 }
143
144
145 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
146 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
147 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
148 }
149
150 // ----------------------------------------------------------------------------
151 // Parallel class loading check
152
153 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
154 if (UnsyncloadClass || class_loader.is_null()) return true;
155 if (AlwaysLockClassLoader) return false;
156 return java_lang_ClassLoader::parallelCapable(class_loader());
157 }
158 // ----------------------------------------------------------------------------
159 // ParallelDefineClass flag does not apply to bootclass loader
160 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
161 if (class_loader.is_null()) return false;
162 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
163 return true;
164 }
165 return false;
166 }
167
168 // Returns true if the passed class loader is the builtin application class loader
169 // or a custom system class loader. A customer system class loader can be
170 // specified via -Djava.system.class.loader.
171 bool SystemDictionary::is_system_class_loader(oop class_loader) {
172 if (class_loader == NULL) {
173 return false;
174 }
175 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
176 class_loader == _java_system_loader);
177 }
178
179 // Returns true if the passed class loader is the platform class loader.
180 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
185 }
186
187 // ----------------------------------------------------------------------------
188 // Resolving of classes
189
190 // Forwards to resolve_or_null
191
192 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
193 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
194 if (HAS_PENDING_EXCEPTION || klass == NULL) {
195 // can return a null klass
196 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
197 }
198 return klass;
199 }
200
201 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
202 bool throw_error,
203 Klass* klass, TRAPS) {
204 if (HAS_PENDING_EXCEPTION) {
205 // If we have a pending exception we forward it to the caller, unless throw_error is true,
206 // in which case we have to check whether the pending exception is a ClassNotFoundException,
207 // and if so convert it to a NoClassDefFoundError
208 // And chain the original ClassNotFoundException
209 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
210 ResourceMark rm(THREAD);
211 assert(klass == NULL, "Should not have result with exception pending");
212 Handle e(THREAD, PENDING_EXCEPTION);
213 CLEAR_PENDING_EXCEPTION;
214 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
215 } else {
216 return NULL;
217 }
218 }
219 // Class not found, throw appropriate error or exception depending on value of throw_error
220 if (klass == NULL) {
221 ResourceMark rm(THREAD);
222 if (throw_error) {
223 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
224 } else {
225 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
226 }
227 }
228 return klass;
229 }
230
231
232 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
233 bool throw_error, TRAPS)
234 {
235 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
236 }
237
238
239 // Forwards to resolve_instance_class_or_null
240
241 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
242 assert(THREAD->can_call_java(),
243 "can not load classes with compiler thread: class=%s, classloader=%s",
244 class_name->as_C_string(),
245 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
246 if (FieldType::is_array(class_name)) {
247 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
248 } else if (FieldType::is_obj(class_name) || FieldType::is_valuetype(class_name)) {
249 ResourceMark rm(THREAD);
250 // Ignore wrapping L and ;. (and Q and ; for value types);
251 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
252 class_name->utf8_length() - 2, CHECK_NULL);
253 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
254 } else {
255 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
256 }
257 }
258
259 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
260 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
261 }
262
263 // Forwards to resolve_instance_class_or_null
264
265 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
266 Handle class_loader,
267 Handle protection_domain,
268 TRAPS) {
269 assert(FieldType::is_array(class_name), "must be array");
270 Klass* k = NULL;
271 FieldArrayInfo fd;
272 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
273 // of this call
274 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
275 if (t == T_OBJECT || t == T_VALUETYPE) {
276 // naked oop "k" is OK here -- we assign back into it
277 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
278 class_loader,
279 protection_domain,
280 CHECK_NULL);
281 if (k != NULL) {
282 k = k->array_klass(fd.dimension(), CHECK_NULL);
283 }
284 } else {
285 k = Universe::typeArrayKlassObj(t);
286 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
287 }
288 return k;
289 }
290
291
292 // Must be called for any super-class or super-interface resolution
293 // during class definition to allow class circularity checking
294 // super-interface callers:
295 // parse_interfaces - for defineClass & jvmtiRedefineClasses
296 // super-class callers:
297 // ClassFileParser - for defineClass & jvmtiRedefineClasses
298 // load_shared_class - while loading a class from shared archive
299 // resolve_instance_class_or_null:
300 // via: handle_parallel_super_load
301 // when resolving a class that has an existing placeholder with
302 // a saved superclass [i.e. a defineClass is currently in progress]
303 // if another thread is trying to resolve the class, it must do
304 // super-class checks on its own thread to catch class circularity
305 // This last call is critical in class circularity checking for cases
306 // where classloading is delegated to different threads and the
307 // classloader lock is released.
308 // Take the case: Base->Super->Base
309 // 1. If thread T1 tries to do a defineClass of class Base
310 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
311 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
312 // so it tries to load Super
313 // 3. If we load the class internally, or user classloader uses same thread
314 // loadClassFromxxx or defineClass via parseClassFile Super ...
315 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
316 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
317 // 3.4 calls resolve_super_or_fail Base
318 // 3.5 finds T1,Base -> throws class circularity
319 //OR 4. If T2 tries to resolve Super via defineClass Super ...
320 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
321 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
322 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
323 // 4.4 finds T2, Super -> throws class circularity
324 // Must be called, even if superclass is null, since this is
325 // where the placeholder entry is created which claims this
326 // thread is loading this class/classloader.
327 // Be careful when modifying this code: once you have run
328 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
329 // you need to find_and_remove it before returning.
330 // So be careful to not exit with a CHECK_ macro betweeen these calls.
331 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
332 Symbol* class_name,
333 Handle class_loader,
334 Handle protection_domain,
335 bool is_superclass,
336 TRAPS) {
337 #if INCLUDE_CDS
338 if (DumpSharedSpaces) {
339 // Special processing for CDS dump time.
340 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
341 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
342 if (k) {
343 return k;
344 }
345 }
346 #endif // INCLUDE_CDS
347
348 // Double-check, if child class is already loaded, just return super-class,interface
349 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
350 // dictionary.
351 // Make sure there's a placeholder for the *child* before resolving.
352 // Used as a claim that this thread is currently loading superclass/classloader
353 // Used here for ClassCircularity checks and also for heap verification
354 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
355 // Must check ClassCircularity before checking if super class is already loaded.
356 //
357 // We might not already have a placeholder if this child_name was
358 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
359 // the name of the class might not be known until the stream is actually
360 // parsed.
361 // Bugs 4643874, 4715493
362
363 ClassLoaderData* loader_data = class_loader_data(class_loader);
364 Dictionary* dictionary = loader_data->dictionary();
365 unsigned int d_hash = dictionary->compute_hash(child_name);
366 int d_index = dictionary->hash_to_index(d_hash);
367 unsigned int p_hash = placeholders()->compute_hash(child_name);
368 int p_index = placeholders()->hash_to_index(p_hash);
369 // can't throw error holding a lock
370 bool child_already_loaded = false;
371 bool throw_circularity_error = false;
372 {
373 MutexLocker mu(SystemDictionary_lock, THREAD);
374 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
375 Klass* quicksuperk;
376 // to support // loading: if child done loading, just return superclass
377 // if class_name, & class_loader don't match:
378 // if initial define, SD update will give LinkageError
379 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
380 // so we don't throw an exception here.
381 // see: nsk redefclass014 & java.lang.instrument Instrument032
382 if ((childk != NULL ) && (is_superclass) &&
383 ((quicksuperk = childk->super()) != NULL) &&
384
385 ((quicksuperk->name() == class_name) &&
386 (quicksuperk->class_loader() == class_loader()))) {
387 return quicksuperk;
388 } else {
389 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
390 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
391 throw_circularity_error = true;
392 }
393 }
394 if (!throw_circularity_error) {
395 // Be careful not to exit resolve_super
396 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
397 }
398 }
399 if (throw_circularity_error) {
400 ResourceMark rm(THREAD);
401 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
402 }
403
404 // java.lang.Object should have been found above
405 assert(class_name != NULL, "null super class for resolving");
406 // Resolve the super class or interface, check results on return
407 Klass* superk = SystemDictionary::resolve_or_null(class_name,
408 class_loader,
409 protection_domain,
410 THREAD);
411
412 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
413 // It is no longer necessary to keep the placeholder table alive until update_dictionary
414 // or error. GC used to walk the placeholder table as strong roots.
415 // The instanceKlass is kept alive because the class loader is on the stack,
416 // which keeps the loader_data alive, as well as all instanceKlasses in
417 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
418 {
419 MutexLocker mu(SystemDictionary_lock, THREAD);
420 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
421 SystemDictionary_lock->notify_all();
422 }
423 if (HAS_PENDING_EXCEPTION || superk == NULL) {
424 // can null superk
425 superk = handle_resolution_exception(class_name, true, superk, THREAD);
426 }
427
428 return superk;
429 }
430
431 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
432 Handle class_loader,
433 Handle protection_domain,
434 TRAPS) {
435 if(!has_checkPackageAccess()) return;
436
437 // Now we have to call back to java to check if the initating class has access
438 JavaValue result(T_VOID);
439 LogTarget(Debug, protectiondomain) lt;
440 if (lt.is_enabled()) {
441 ResourceMark rm;
442 // Print out trace information
443 LogStream ls(lt);
444 ls.print_cr("Checking package access");
445 ls.print("class loader: "); class_loader()->print_value_on(&ls);
446 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
447 ls.print(" loading: "); klass->print_value_on(&ls);
448 ls.cr();
449 }
450
451 // This handle and the class_loader handle passed in keeps this class from
452 // being unloaded through several GC points.
453 // The class_loader handle passed in is the initiating loader.
454 Handle mirror(THREAD, klass->java_mirror());
455
456 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
457 JavaCalls::call_special(&result,
458 class_loader,
459 system_loader,
460 vmSymbols::checkPackageAccess_name(),
461 vmSymbols::class_protectiondomain_signature(),
462 mirror,
463 protection_domain,
464 THREAD);
465
466 if (HAS_PENDING_EXCEPTION) {
467 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
468 } else {
469 log_debug(protectiondomain)("granted");
470 }
471
472 if (HAS_PENDING_EXCEPTION) return;
473
474 // If no exception has been thrown, we have validated the protection domain
475 // Insert the protection domain of the initiating class into the set.
476 {
477 ClassLoaderData* loader_data = class_loader_data(class_loader);
478 Dictionary* dictionary = loader_data->dictionary();
479
480 Symbol* kn = klass->name();
481 unsigned int d_hash = dictionary->compute_hash(kn);
482 int d_index = dictionary->hash_to_index(d_hash);
483
484 MutexLocker mu(SystemDictionary_lock, THREAD);
485 dictionary->add_protection_domain(d_index, d_hash, klass,
486 protection_domain, THREAD);
487 }
488 }
489
490 // We only get here if this thread finds that another thread
491 // has already claimed the placeholder token for the current operation,
492 // but that other thread either never owned or gave up the
493 // object lock
494 // Waits on SystemDictionary_lock to indicate placeholder table updated
495 // On return, caller must recheck placeholder table state
496 //
497 // We only get here if
498 // 1) custom classLoader, i.e. not bootstrap classloader
499 // 2) UnsyncloadClass not set
500 // 3) custom classLoader has broken the class loader objectLock
501 // so another thread got here in parallel
502 //
503 // lockObject must be held.
504 // Complicated dance due to lock ordering:
505 // Must first release the classloader object lock to
506 // allow initial definer to complete the class definition
507 // and to avoid deadlock
508 // Reclaim classloader lock object with same original recursion count
509 // Must release SystemDictionary_lock after notify, since
510 // class loader lock must be claimed before SystemDictionary_lock
511 // to prevent deadlocks
512 //
513 // The notify allows applications that did an untimed wait() on
514 // the classloader object lock to not hang.
515 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
516 assert_lock_strong(SystemDictionary_lock);
517
518 bool calledholdinglock
519 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
520 assert(calledholdinglock,"must hold lock for notify");
521 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
522 ObjectSynchronizer::notifyall(lockObject, THREAD);
523 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
524 SystemDictionary_lock->wait();
525 SystemDictionary_lock->unlock();
526 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
527 SystemDictionary_lock->lock();
528 }
529
530 // If the class in is in the placeholder table, class loading is in progress
531 // For cases where the application changes threads to load classes, it
532 // is critical to ClassCircularity detection that we try loading
533 // the superclass on the same thread internally, so we do parallel
534 // super class loading here.
535 // This also is critical in cases where the original thread gets stalled
536 // even in non-circularity situations.
537 // Note: must call resolve_super_or_fail even if null super -
538 // to force placeholder entry creation for this class for circularity detection
539 // Caller must check for pending exception
540 // Returns non-null Klass* if other thread has completed load
541 // and we are done,
542 // If return null Klass* and no pending exception, the caller must load the class
543 InstanceKlass* SystemDictionary::handle_parallel_super_load(
544 Symbol* name, Symbol* superclassname, Handle class_loader,
545 Handle protection_domain, Handle lockObject, TRAPS) {
546
547 ClassLoaderData* loader_data = class_loader_data(class_loader);
548 Dictionary* dictionary = loader_data->dictionary();
549 unsigned int d_hash = dictionary->compute_hash(name);
550 int d_index = dictionary->hash_to_index(d_hash);
551 unsigned int p_hash = placeholders()->compute_hash(name);
552 int p_index = placeholders()->hash_to_index(p_hash);
553
554 // superk is not used, resolve_super called for circularity check only
555 // This code is reached in two situations. One if this thread
556 // is loading the same class twice (e.g. ClassCircularity, or
557 // java.lang.instrument).
558 // The second is if another thread started the resolve_super first
559 // and has not yet finished.
560 // In both cases the original caller will clean up the placeholder
561 // entry on error.
562 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
563 superclassname,
564 class_loader,
565 protection_domain,
566 true,
567 CHECK_NULL);
568
569 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
570 // Serial class loaders and bootstrap classloader do wait for superclass loads
571 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
572 MutexLocker mu(SystemDictionary_lock, THREAD);
573 // Check if classloading completed while we were loading superclass or waiting
574 return find_class(d_index, d_hash, name, dictionary);
575 }
576
577 // must loop to both handle other placeholder updates
578 // and spurious notifications
579 bool super_load_in_progress = true;
580 PlaceholderEntry* placeholder;
581 while (super_load_in_progress) {
582 MutexLocker mu(SystemDictionary_lock, THREAD);
583 // Check if classloading completed while we were loading superclass or waiting
584 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
585 if (check != NULL) {
586 // Klass is already loaded, so just return it
587 return check;
588 } else {
589 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
590 if (placeholder && placeholder->super_load_in_progress() ){
591 // Before UnsyncloadClass:
592 // We only get here if the application has released the
593 // classloader lock when another thread was in the middle of loading a
594 // superclass/superinterface for this class, and now
595 // this thread is also trying to load this class.
596 // To minimize surprises, the first thread that started to
597 // load a class should be the one to complete the loading
598 // with the classfile it initially expected.
599 // This logic has the current thread wait once it has done
600 // all the superclass/superinterface loading it can, until
601 // the original thread completes the class loading or fails
602 // If it completes we will use the resulting InstanceKlass
603 // which we will find below in the systemDictionary.
604 // We also get here for parallel bootstrap classloader
605 if (class_loader.is_null()) {
606 SystemDictionary_lock->wait();
607 } else {
608 double_lock_wait(lockObject, THREAD);
609 }
610 } else {
611 // If not in SD and not in PH, other thread's load must have failed
612 super_load_in_progress = false;
613 }
614 }
615 }
616 return NULL;
617 }
618
619 static void post_class_load_event(const Ticks& start_time,
620 InstanceKlass* k,
621 const ClassLoaderData* init_cld) {
622 #if INCLUDE_TRACE
623 EventClassLoad event(UNTIMED);
624 if (event.should_commit()) {
625 event.set_starttime(start_time);
626 event.set_loadedClass(k);
627 event.set_definingClassLoader(k->class_loader_data());
628 event.set_initiatingClassLoader(init_cld);
629 event.commit();
630 }
631 #endif // INCLUDE_TRACE
632 }
633
634 static void class_define_event(InstanceKlass* k,
635 const ClassLoaderData* def_cld) {
636 #if INCLUDE_TRACE
637 EventClassDefine event;
638 if (event.should_commit()) {
639 event.set_definedClass(k);
640 event.set_definingClassLoader(def_cld);
641 event.commit();
642 }
643 #endif // INCLUDE_TRACE
644 }
645
646 // Be careful when modifying this code: once you have run
647 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
648 // you need to find_and_remove it before returning.
649 // So be careful to not exit with a CHECK_ macro betweeen these calls.
650 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
651 Handle class_loader,
652 Handle protection_domain,
653 TRAPS) {
654 assert(name != NULL && !FieldType::is_array(name) &&
655 !FieldType::is_obj(name) && !FieldType::is_valuetype(name), "invalid class name");
656
657 Ticks class_load_start_time = Ticks::now();
658
659 HandleMark hm(THREAD);
660
661 // Fix for 4474172; see evaluation for more details
662 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
663 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
664 Dictionary* dictionary = loader_data->dictionary();
665
666 // Do lookup to see if class already exist and the protection domain
667 // has the right access
668 // This call uses find which checks protection domain already matches
669 // All subsequent calls use find_class, and set has_loaded_class so that
670 // before we return a result we call out to java to check for valid protection domain
671 // to allow returning the Klass* and add it to the pd_set if it is valid
672 unsigned int d_hash = dictionary->compute_hash(name);
673 int d_index = dictionary->hash_to_index(d_hash);
674 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
675 if (probe != NULL) return probe;
676
677
678 // Non-bootstrap class loaders will call out to class loader and
679 // define via jvm/jni_DefineClass which will acquire the
680 // class loader object lock to protect against multiple threads
681 // defining the class in parallel by accident.
682 // This lock must be acquired here so the waiter will find
683 // any successful result in the SystemDictionary and not attempt
684 // the define
685 // ParallelCapable Classloaders and the bootstrap classloader,
686 // or all classloaders with UnsyncloadClass do not acquire lock here
687 bool DoObjectLock = true;
688 if (is_parallelCapable(class_loader)) {
689 DoObjectLock = false;
690 }
691
692 unsigned int p_hash = placeholders()->compute_hash(name);
693 int p_index = placeholders()->hash_to_index(p_hash);
694
695 // Class is not in SystemDictionary so we have to do loading.
696 // Make sure we are synchronized on the class loader before we proceed
697 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
698 check_loader_lock_contention(lockObject, THREAD);
699 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
700
701 // Check again (after locking) if class already exist in SystemDictionary
702 bool class_has_been_loaded = false;
703 bool super_load_in_progress = false;
704 bool havesupername = false;
705 InstanceKlass* k = NULL;
706 PlaceholderEntry* placeholder;
707 Symbol* superclassname = NULL;
708
709 {
710 MutexLocker mu(SystemDictionary_lock, THREAD);
711 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
712 if (check != NULL) {
713 // Klass is already loaded, so just return it
714 class_has_been_loaded = true;
715 k = check;
716 } else {
717 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
718 if (placeholder && placeholder->super_load_in_progress()) {
719 super_load_in_progress = true;
720 if (placeholder->havesupername() == true) {
721 superclassname = placeholder->supername();
722 havesupername = true;
723 }
724 }
725 }
726 }
727
728 // If the class is in the placeholder table, class loading is in progress
729 if (super_load_in_progress && havesupername==true) {
730 k = handle_parallel_super_load(name,
731 superclassname,
732 class_loader,
733 protection_domain,
734 lockObject, THREAD);
735 if (HAS_PENDING_EXCEPTION) {
736 return NULL;
737 }
738 if (k != NULL) {
739 class_has_been_loaded = true;
740 }
741 }
742
743 bool throw_circularity_error = false;
744 if (!class_has_been_loaded) {
745 bool load_instance_added = false;
746
747 // add placeholder entry to record loading instance class
748 // Five cases:
749 // All cases need to prevent modifying bootclasssearchpath
750 // in parallel with a classload of same classname
751 // Redefineclasses uses existence of the placeholder for the duration
752 // of the class load to prevent concurrent redefinition of not completely
753 // defined classes.
754 // case 1. traditional classloaders that rely on the classloader object lock
755 // - no other need for LOAD_INSTANCE
756 // case 2. traditional classloaders that break the classloader object lock
757 // as a deadlock workaround. Detection of this case requires that
758 // this check is done while holding the classloader object lock,
759 // and that lock is still held when calling classloader's loadClass.
760 // For these classloaders, we ensure that the first requestor
761 // completes the load and other requestors wait for completion.
762 // case 3. UnsyncloadClass - don't use objectLocker
763 // With this flag, we allow parallel classloading of a
764 // class/classloader pair
765 // case4. Bootstrap classloader - don't own objectLocker
766 // This classloader supports parallelism at the classloader level,
767 // but only allows a single load of a class/classloader pair.
768 // No performance benefit and no deadlock issues.
769 // case 5. parallelCapable user level classloaders - without objectLocker
770 // Allow parallel classloading of a class/classloader pair
771
772 {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
776 if (oldprobe) {
777 // only need check_seen_thread once, not on each loop
778 // 6341374 java/lang/Instrument with -Xcomp
779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
780 throw_circularity_error = true;
781 } else {
782 // case 1: traditional: should never see load_in_progress.
783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
784
785 // case 4: bootstrap classloader: prevent futile classloading,
786 // wait on first requestor
787 if (class_loader.is_null()) {
788 SystemDictionary_lock->wait();
789 } else {
790 // case 2: traditional with broken classloader lock. wait on first
791 // requestor.
792 double_lock_wait(lockObject, THREAD);
793 }
794 // Check if classloading completed while we were waiting
795 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
796 if (check != NULL) {
797 // Klass is already loaded, so just return it
798 k = check;
799 class_has_been_loaded = true;
800 }
801 // check if other thread failed to load and cleaned up
802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
803 }
804 }
805 }
806 }
807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
808 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
809 // LOAD_INSTANCE in parallel
810
811 if (!throw_circularity_error && !class_has_been_loaded) {
812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
813 load_instance_added = true;
814 // For class loaders that do not acquire the classloader object lock,
815 // if they did not catch another thread holding LOAD_INSTANCE,
816 // need a check analogous to the acquire ObjectLocker/find_class
817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
818 // one final check if the load has already completed
819 // class loaders holding the ObjectLock shouldn't find the class here
820 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
821 if (check != NULL) {
822 // Klass is already loaded, so return it after checking/adding protection domain
823 k = check;
824 class_has_been_loaded = true;
825 }
826 }
827 }
828
829 // must throw error outside of owning lock
830 if (throw_circularity_error) {
831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
832 ResourceMark rm(THREAD);
833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
834 }
835
836 if (!class_has_been_loaded) {
837
838 // Do actual loading
839 k = load_instance_class(name, class_loader, THREAD);
840
841 // For UnsyncloadClass only
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 (UnsyncloadClass || (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_index, 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_index, 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_index, 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_time, 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 {
919 MutexLocker mu(SystemDictionary_lock, THREAD);
920 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
921 protection_domain)) {
922 return k;
923 }
924 }
925
926 // Verify protection domain. If it fails an exception is thrown
927 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
928
929 return k;
930 }
931
932
933 // This routine does not lock the system dictionary.
934 //
935 // Since readers don't hold a lock, we must make sure that system
936 // dictionary entries are only removed at a safepoint (when only one
937 // thread is running), and are added to in a safe way (all links must
938 // be updated in an MT-safe manner).
939 //
940 // Callers should be aware that an entry could be added just after
941 // _dictionary->bucket(index) is read here, so the caller will not see
942 // the new entry.
943
944 Klass* SystemDictionary::find(Symbol* class_name,
945 Handle class_loader,
946 Handle protection_domain,
947 TRAPS) {
948
949 // The result of this call should be consistent with the result
950 // of the call to resolve_instance_class_or_null().
951 // See evaluation 6790209 and 4474172 for more details.
952 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
953 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
954
955 if (loader_data == NULL) {
956 // If the ClassLoaderData has not been setup,
957 // then the class loader has no entries in the dictionary.
958 return NULL;
959 }
960
961 Dictionary* dictionary = loader_data->dictionary();
962 unsigned int d_hash = dictionary->compute_hash(class_name);
963 int d_index = dictionary->hash_to_index(d_hash);
964 return dictionary->find(d_index, d_hash, class_name,
965 protection_domain);
966 }
967
968
969 // Look for a loaded instance or array klass by name. Do not do any loading.
970 // return NULL in case of error.
971 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
972 Handle class_loader,
973 Handle protection_domain,
974 TRAPS) {
975 Klass* k = NULL;
976 assert(class_name != NULL, "class name must be non NULL");
977
978 if (FieldType::is_array(class_name)) {
979 // The name refers to an array. Parse the name.
980 // dimension and object_key in FieldArrayInfo are assigned as a
981 // side-effect of this call
982 FieldArrayInfo fd;
983 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
984 if (t != T_OBJECT && t != T_VALUETYPE) {
985 k = Universe::typeArrayKlassObj(t);
986 } else {
987 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
988 }
989 if (k != NULL) {
990 k = k->array_klass_or_null(fd.dimension());
991 }
992 } else {
993 k = find(class_name, class_loader, protection_domain, THREAD);
994 }
995 return k;
996 }
997
998 // Note: this method is much like resolve_from_stream, but
999 // does not publish the classes via the SystemDictionary.
1000 // Handles unsafe_DefineAnonymousClass and redefineclasses
1001 // RedefinedClasses do not add to the class hierarchy
1002 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1003 Handle class_loader,
1004 Handle protection_domain,
1005 ClassFileStream* st,
1006 const InstanceKlass* host_klass,
1007 GrowableArray<Handle>* cp_patches,
1008 TRAPS) {
1009
1010 Ticks class_load_start_time = Ticks::now();
1011
1012 ClassLoaderData* loader_data;
1013 if (host_klass != NULL) {
1014 // Create a new CLD for anonymous class, that uses the same class loader
1015 // as the host_klass
1016 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1017 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1018 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1019 } else {
1020 loader_data = ClassLoaderData::class_loader_data(class_loader());
1021 }
1022
1023 assert(st != NULL, "invariant");
1024 assert(st->need_verify(), "invariant");
1025
1026 // Parse stream and create a klass.
1027 // Note that we do this even though this klass might
1028 // already be present in the SystemDictionary, otherwise we would not
1029 // throw potential ClassFormatErrors.
1030
1031 InstanceKlass* k = KlassFactory::create_from_stream(st,
1032 class_name,
1033 loader_data,
1034 protection_domain,
1035 host_klass,
1036 cp_patches,
1037 CHECK_NULL);
1038
1039 if (host_klass != NULL && k != NULL) {
1040 // If it's anonymous, initialize it now, since nobody else will.
1041
1042 {
1043 MutexLocker mu_r(Compile_lock, THREAD);
1044
1045 // Add to class hierarchy, initialize vtables, and do possible
1046 // deoptimizations.
1047 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1048
1049 // But, do not add to dictionary.
1050
1051 // compiled code dependencies need to be validated anyway
1052 notice_modification();
1053 }
1054
1055 // Rewrite and patch constant pool here.
1056 k->link_class(CHECK_NULL);
1057 if (cp_patches != NULL) {
1058 k->constants()->patch_resolved_references(cp_patches);
1059 }
1060 k->eager_initialize(CHECK_NULL);
1061
1062 // notify jvmti
1063 if (JvmtiExport::should_post_class_load()) {
1064 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1065 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1066 }
1067
1068 post_class_load_event(class_load_start_time, k, loader_data);
1069 }
1070 assert(host_klass != NULL || NULL == cp_patches,
1071 "cp_patches only found with host_klass");
1072
1073 return k;
1074 }
1075
1076 // Add a klass to the system from a stream (called by jni_DefineClass and
1077 // JVM_DefineClass).
1078 // Note: class_name can be NULL. In that case we do not know the name of
1079 // the class until we have parsed the stream.
1080
1081 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1082 Handle class_loader,
1083 Handle protection_domain,
1084 ClassFileStream* st,
1085 TRAPS) {
1086
1087 HandleMark hm(THREAD);
1088
1089 // Classloaders that support parallelism, e.g. bootstrap classloader,
1090 // or all classloaders with UnsyncloadClass do not acquire lock here
1091 bool DoObjectLock = true;
1092 if (is_parallelCapable(class_loader)) {
1093 DoObjectLock = false;
1094 }
1095
1096 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1097
1098 // Make sure we are synchronized on the class loader before we proceed
1099 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1100 check_loader_lock_contention(lockObject, THREAD);
1101 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1102
1103 assert(st != NULL, "invariant");
1104
1105 // Parse the stream and create a klass.
1106 // Note that we do this even though this klass might
1107 // already be present in the SystemDictionary, otherwise we would not
1108 // throw potential ClassFormatErrors.
1109 InstanceKlass* k = NULL;
1110
1111 #if INCLUDE_CDS
1112 k = SystemDictionaryShared::lookup_from_stream(class_name,
1113 class_loader,
1114 protection_domain,
1115 st,
1116 CHECK_NULL);
1117 #endif
1118
1119 if (k == NULL) {
1120 if (st->buffer() == NULL) {
1121 return NULL;
1122 }
1123 k = KlassFactory::create_from_stream(st,
1124 class_name,
1125 loader_data,
1126 protection_domain,
1127 NULL, // host_klass
1128 NULL, // cp_patches
1129 CHECK_NULL);
1130 }
1131
1132 assert(k != NULL, "no klass created");
1133 Symbol* h_name = k->name();
1134 assert(class_name == NULL || class_name == h_name, "name mismatch");
1135
1136 // Add class just loaded
1137 // If a class loader supports parallel classloading handle parallel define requests
1138 // find_or_define_instance_class may return a different InstanceKlass
1139 if (is_parallelCapable(class_loader)) {
1140 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1141 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1142 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1143 assert(defined_k != NULL, "Should have a klass if there's no exception");
1144 loader_data->add_to_deallocate_list(k);
1145 k = defined_k;
1146 }
1147 } else {
1148 define_instance_class(k, THREAD);
1149 }
1150
1151 // If defining the class throws an exception register 'k' for cleanup.
1152 if (HAS_PENDING_EXCEPTION) {
1153 assert(k != NULL, "Must have an instance klass here!");
1154 loader_data->add_to_deallocate_list(k);
1155 return NULL;
1156 }
1157
1158 // Make sure we have an entry in the SystemDictionary on success
1159 debug_only( {
1160 MutexLocker mu(SystemDictionary_lock, THREAD);
1161
1162 Klass* check = find_class(h_name, k->class_loader_data());
1163 assert(check == k, "should be present in the dictionary");
1164 } );
1165
1166 return k;
1167 }
1168
1169 #if INCLUDE_CDS
1170 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1171 int number_of_entries) {
1172 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1173 "bad shared dictionary size.");
1174 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1175 _shared_dictionary_size, t, number_of_entries);
1176 }
1177
1178
1179 // If there is a shared dictionary, then find the entry for the
1180 // given shared system class, if any.
1181
1182 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1183 if (shared_dictionary() != NULL) {
1184 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1185 int d_index = shared_dictionary()->hash_to_index(d_hash);
1186
1187 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1188 } else {
1189 return NULL;
1190 }
1191 }
1192
1193
1194 // Load a class from the shared spaces (found through the shared system
1195 // dictionary). Force the superclass and all interfaces to be loaded.
1196 // Update the class definition to include sibling classes and no
1197 // subclasses (yet). [Classes in the shared space are not part of the
1198 // object hierarchy until loaded.]
1199
1200 InstanceKlass* SystemDictionary::load_shared_class(
1201 Symbol* class_name, Handle class_loader, TRAPS) {
1202 InstanceKlass* ik = find_shared_class(class_name);
1203 // Make sure we only return the boot class for the NULL classloader.
1204 if (ik != NULL &&
1205 ik->is_shared_boot_class() && class_loader.is_null()) {
1206 Handle protection_domain;
1207 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1208 }
1209 return NULL;
1210 }
1211
1212 // Check if a shared class can be loaded by the specific classloader:
1213 //
1214 // NULL classloader:
1215 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1216 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1217 // be defined in an unnamed module.
1218 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1219 InstanceKlass* ik,
1220 Handle class_loader, TRAPS) {
1221 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1222 "Cannot use sharing if java.base is patched");
1223 ResourceMark rm;
1224 int path_index = ik->shared_classpath_index();
1225 SharedClassPathEntry* ent =
1226 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1227 if (!Universe::is_module_initialized()) {
1228 assert(ent != NULL && ent->is_jrt(),
1229 "Loading non-bootstrap classes before the module system is initialized");
1230 assert(class_loader.is_null(), "sanity");
1231 return true;
1232 }
1233 // Get the pkg_entry from the classloader
1234 TempNewSymbol pkg_name = NULL;
1235 PackageEntry* pkg_entry = NULL;
1236 ModuleEntry* mod_entry = NULL;
1237 const char* pkg_string = NULL;
1238 ClassLoaderData* loader_data = class_loader_data(class_loader);
1239 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1240 if (pkg_name != NULL) {
1241 pkg_string = pkg_name->as_C_string();
1242 if (loader_data != NULL) {
1243 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1244 }
1245 if (pkg_entry != NULL) {
1246 mod_entry = pkg_entry->module();
1247 }
1248 }
1249
1250 // If the archived class is from a module that has been patched at runtime,
1251 // the class cannot be loaded from the archive.
1252 if (mod_entry != NULL && mod_entry->is_patched()) {
1253 return false;
1254 }
1255
1256 if (class_loader.is_null()) {
1257 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1258 // The NULL classloader can load archived class originated from the
1259 // "modules" jimage and the -Xbootclasspath/a. For class from the
1260 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1261 // by the NULL classloader.
1262 if (mod_entry != NULL) {
1263 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1264 // ModuleEntry's location agrees with the archived class' origination.
1265 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1266 return true; // Module class from the "module" jimage
1267 }
1268 }
1269
1270 // If the archived class is not from the "module" jimage, the class can be
1271 // loaded by the NULL classloader if
1272 //
1273 // 1. the class is from the unamed package
1274 // 2. or, the class is not from a module defined in the NULL classloader
1275 // 3. or, the class is from an unamed module
1276 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1277 // the class is from the -Xbootclasspath/a
1278 if (pkg_string == NULL ||
1279 pkg_entry == NULL ||
1280 pkg_entry->in_unnamed_module()) {
1281 assert(mod_entry == NULL ||
1282 mod_entry == loader_data->unnamed_module(),
1283 "the unnamed module is not defined in the classloader");
1284 return true;
1285 }
1286 }
1287 return false;
1288 } else {
1289 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1290 ik, class_loader, pkg_string, pkg_name,
1291 pkg_entry, mod_entry, CHECK_(false));
1292 return res;
1293 }
1294 }
1295
1296 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1297 Handle class_loader,
1298 Handle protection_domain, TRAPS) {
1299
1300 if (ik != NULL) {
1301 Symbol* class_name = ik->name();
1302
1303 bool visible = is_shared_class_visible(
1304 class_name, ik, class_loader, CHECK_NULL);
1305 if (!visible) {
1306 return NULL;
1307 }
1308
1309 // Resolve the superclass and interfaces. They must be the same
1310 // as in dump time, because the layout of <ik> depends on
1311 // the specific layout of ik->super() and ik->local_interfaces().
1312 //
1313 // If unexpected superclass or interfaces are found, we cannot
1314 // load <ik> from the shared archive.
1315
1316 if (ik->super() != NULL) {
1317 Symbol* cn = ik->super()->name();
1318 Klass *s = resolve_super_or_fail(class_name, cn,
1319 class_loader, protection_domain, true, CHECK_NULL);
1320 if (s != ik->super()) {
1321 // The dynamically resolved super class is not the same as the one we used during dump time,
1322 // so we cannot use ik.
1323 return NULL;
1324 } else {
1325 assert(s->is_shared(), "must be");
1326 }
1327 }
1328
1329 Array<Klass*>* interfaces = ik->local_interfaces();
1330 int num_interfaces = interfaces->length();
1331 for (int index = 0; index < num_interfaces; index++) {
1332 Klass* k = interfaces->at(index);
1333 Symbol* name = k->name();
1334 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1335 if (k != i) {
1336 // The dynamically resolved interface class is not the same as the one we used during dump time,
1337 // so we cannot use ik.
1338 return NULL;
1339 } else {
1340 assert(i->is_shared(), "must be");
1341 }
1342 }
1343
1344 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1345 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1346 if (new_ik != NULL) {
1347 // The class is changed by CFLH. Return the new class. The shared class is
1348 // not used.
1349 return new_ik;
1350 }
1351
1352 // Adjust methods to recover missing data. They need addresses for
1353 // interpreter entry points and their default native method address
1354 // must be reset.
1355
1356 // Updating methods must be done under a lock so multiple
1357 // threads don't update these in parallel
1358 //
1359 // Shared classes are all currently loaded by either the bootstrap or
1360 // internal parallel class loaders, so this will never cause a deadlock
1361 // on a custom class loader lock.
1362
1363 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1364 {
1365 HandleMark hm(THREAD);
1366 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1367 check_loader_lock_contention(lockObject, THREAD);
1368 ObjectLocker ol(lockObject, THREAD, true);
1369 // prohibited package check assumes all classes loaded from archive call
1370 // restore_unshareable_info which calls ik->set_package()
1371 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1372 }
1373
1374 ik->print_class_load_logging(loader_data, NULL, NULL);
1375
1376 // For boot loader, ensure that GetSystemPackage knows that a class in this
1377 // package was loaded.
1378 if (class_loader.is_null()) {
1379 int path_index = ik->shared_classpath_index();
1380 ResourceMark rm;
1381 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1382 }
1383
1384 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1385 // Only dump the classes that can be stored into CDS archive
1386 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1387 ResourceMark rm(THREAD);
1388 classlist_file->print_cr("%s", ik->name()->as_C_string());
1389 classlist_file->flush();
1390 }
1391 }
1392
1393 // notify a class loaded from shared object
1394 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1395 }
1396
1397 ik->set_has_passed_fingerprint_check(false);
1398 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1399 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1400 uint64_t cds_fp = ik->get_stored_fingerprint();
1401 if (aot_fp != 0 && aot_fp == cds_fp) {
1402 // This class matches with a class saved in an AOT library
1403 ik->set_has_passed_fingerprint_check(true);
1404 } else {
1405 ResourceMark rm;
1406 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1407 }
1408 }
1409 return ik;
1410 }
1411 #endif // INCLUDE_CDS
1412
1413 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1414
1415 if (class_loader.is_null()) {
1416 ResourceMark rm;
1417 PackageEntry* pkg_entry = NULL;
1418 bool search_only_bootloader_append = false;
1419 ClassLoaderData *loader_data = class_loader_data(class_loader);
1420
1421 // Find the package in the boot loader's package entry table.
1422 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1423 if (pkg_name != NULL) {
1424 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1425 }
1426
1427 // Prior to attempting to load the class, enforce the boot loader's
1428 // visibility boundaries.
1429 if (!Universe::is_module_initialized()) {
1430 // During bootstrapping, prior to module initialization, any
1431 // class attempting to be loaded must be checked against the
1432 // java.base packages in the boot loader's PackageEntryTable.
1433 // No class outside of java.base is allowed to be loaded during
1434 // this bootstrapping window.
1435 if (!DumpSharedSpaces) {
1436 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1437 // Class is either in the unnamed package or in
1438 // a named package within the unnamed module. Either
1439 // case is outside of java.base, do not attempt to
1440 // load the class post java.base definition. If
1441 // java.base has not been defined, let the class load
1442 // and its package will be checked later by
1443 // ModuleEntryTable::verify_javabase_packages.
1444 if (ModuleEntryTable::javabase_defined()) {
1445 return NULL;
1446 }
1447 } else {
1448 // Check that the class' package is defined within java.base.
1449 ModuleEntry* mod_entry = pkg_entry->module();
1450 Symbol* mod_entry_name = mod_entry->name();
1451 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1452 return NULL;
1453 }
1454 }
1455 }
1456 } else {
1457 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1458 // After the module system has been initialized, check if the class'
1459 // package is in a module defined to the boot loader.
1460 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1461 // Class is either in the unnamed package, in a named package
1462 // within a module not defined to the boot loader or in a
1463 // a named package within the unnamed module. In all cases,
1464 // limit visibility to search for the class only in the boot
1465 // loader's append path.
1466 search_only_bootloader_append = true;
1467 }
1468 }
1469
1470 // Prior to bootstrapping's module initialization, never load a class outside
1471 // of the boot loader's module path
1472 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1473 !search_only_bootloader_append,
1474 "Attempt to load a class outside of boot loader's module path");
1475
1476 // Search the shared system dictionary for classes preloaded into the
1477 // shared spaces.
1478 InstanceKlass* k = NULL;
1479 {
1480 #if INCLUDE_CDS
1481 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1482 k = load_shared_class(class_name, class_loader, THREAD);
1483 #endif
1484 }
1485
1486 if (k == NULL) {
1487 // Use VM class loader
1488 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1489 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1490 }
1491
1492 // find_or_define_instance_class may return a different InstanceKlass
1493 if (k != NULL) {
1494 InstanceKlass* defined_k =
1495 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1496 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1497 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1498 assert(defined_k != NULL, "Should have a klass if there's no exception");
1499 loader_data->add_to_deallocate_list(k);
1500 k = defined_k;
1501 } else if (HAS_PENDING_EXCEPTION) {
1502 loader_data->add_to_deallocate_list(k);
1503 return NULL;
1504 }
1505 }
1506 return k;
1507 } else {
1508 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1509 ResourceMark rm(THREAD);
1510
1511 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1512 JavaThread* jt = (JavaThread*) THREAD;
1513
1514 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1515 ClassLoader::perf_app_classload_selftime(),
1516 ClassLoader::perf_app_classload_count(),
1517 jt->get_thread_stat()->perf_recursion_counts_addr(),
1518 jt->get_thread_stat()->perf_timers_addr(),
1519 PerfClassTraceTime::CLASS_LOAD);
1520
1521 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1522 // Translate to external class name format, i.e., convert '/' chars to '.'
1523 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1524
1525 JavaValue result(T_OBJECT);
1526
1527 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1528
1529 // Call public unsynchronized loadClass(String) directly for all class loaders
1530 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1531 // acquire a class-name based lock rather than the class loader object lock.
1532 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1533 // so the call to loadClassInternal() was not required.
1534 //
1535 // UnsyncloadClass flag means both call loadClass(String) and do
1536 // not acquire the class loader lock even for class loaders that are
1537 // not parallelCapable. This was a risky transitional
1538 // flag for diagnostic purposes only. It is risky to call
1539 // custom class loaders without synchronization.
1540 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1541 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1542 // Do NOT assume this will be supported in future releases.
1543 //
1544 // Added MustCallLoadClassInternal in case we discover in the field
1545 // a customer that counts on this call
1546 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1547 JavaCalls::call_special(&result,
1548 class_loader,
1549 spec_klass,
1550 vmSymbols::loadClassInternal_name(),
1551 vmSymbols::string_class_signature(),
1552 string,
1553 CHECK_NULL);
1554 } else {
1555 JavaCalls::call_virtual(&result,
1556 class_loader,
1557 spec_klass,
1558 vmSymbols::loadClass_name(),
1559 vmSymbols::string_class_signature(),
1560 string,
1561 CHECK_NULL);
1562 }
1563
1564 assert(result.get_type() == T_OBJECT, "just checking");
1565 oop obj = (oop) result.get_jobject();
1566
1567 // Primitive classes return null since forName() can not be
1568 // used to obtain any of the Class objects representing primitives or void
1569 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1570 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1571 // For user defined Java class loaders, check that the name returned is
1572 // the same as that requested. This check is done for the bootstrap
1573 // loader when parsing the class file.
1574 if (class_name == k->name()) {
1575 return k;
1576 }
1577 }
1578 // Class is not found or has the wrong name, return NULL
1579 return NULL;
1580 }
1581 }
1582
1583 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1584
1585 HandleMark hm(THREAD);
1586 ClassLoaderData* loader_data = k->class_loader_data();
1587 Handle class_loader_h(THREAD, loader_data->class_loader());
1588
1589 // for bootstrap and other parallel classloaders don't acquire lock,
1590 // use placeholder token
1591 // If a parallelCapable class loader calls define_instance_class instead of
1592 // find_or_define_instance_class to get here, we have a timing
1593 // hole with systemDictionary updates and check_constraints
1594 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1595 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1596 compute_loader_lock_object(class_loader_h, THREAD)),
1597 "define called without lock");
1598 }
1599
1600 // Check class-loading constraints. Throw exception if violation is detected.
1601 // Grabs and releases SystemDictionary_lock
1602 // The check_constraints/find_class call and update_dictionary sequence
1603 // must be "atomic" for a specific class/classloader pair so we never
1604 // define two different instanceKlasses for that class/classloader pair.
1605 // Existing classloaders will call define_instance_class with the
1606 // classloader lock held
1607 // Parallel classloaders will call find_or_define_instance_class
1608 // which will require a token to perform the define class
1609 Symbol* name_h = k->name();
1610 Dictionary* dictionary = loader_data->dictionary();
1611 unsigned int d_hash = dictionary->compute_hash(name_h);
1612 int d_index = dictionary->hash_to_index(d_hash);
1613 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1614
1615 // Register class just loaded with class loader (placed in Vector)
1616 // Note we do this before updating the dictionary, as this can
1617 // fail with an OutOfMemoryError (if it does, we will *not* put this
1618 // class in the dictionary and will not update the class hierarchy).
1619 // JVMTI FollowReferences needs to find the classes this way.
1620 if (k->class_loader() != NULL) {
1621 methodHandle m(THREAD, Universe::loader_addClass_method());
1622 JavaValue result(T_VOID);
1623 JavaCallArguments args(class_loader_h);
1624 args.push_oop(Handle(THREAD, k->java_mirror()));
1625 JavaCalls::call(&result, m, &args, CHECK);
1626 }
1627
1628 // Add the new class. We need recompile lock during update of CHA.
1629 {
1630 unsigned int p_hash = placeholders()->compute_hash(name_h);
1631 int p_index = placeholders()->hash_to_index(p_hash);
1632
1633 MutexLocker mu_r(Compile_lock, THREAD);
1634
1635 // Add to class hierarchy, initialize vtables, and do possible
1636 // deoptimizations.
1637 add_to_hierarchy(k, CHECK); // No exception, but can block
1638
1639 // Add to systemDictionary - so other classes can see it.
1640 // Grabs and releases SystemDictionary_lock
1641 update_dictionary(d_index, d_hash, p_index, p_hash,
1642 k, class_loader_h, THREAD);
1643 }
1644 k->eager_initialize(THREAD);
1645
1646 // notify jvmti
1647 if (JvmtiExport::should_post_class_load()) {
1648 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1649 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1650
1651 }
1652 class_define_event(k, loader_data);
1653 }
1654
1655 // Support parallel classloading
1656 // All parallel class loaders, including bootstrap classloader
1657 // lock a placeholder entry for this class/class_loader pair
1658 // to allow parallel defines of different classes for this class loader
1659 // With AllowParallelDefine flag==true, in case they do not synchronize around
1660 // FindLoadedClass/DefineClass, calls, we check for parallel
1661 // loading for them, wait if a defineClass is in progress
1662 // and return the initial requestor's results
1663 // This flag does not apply to the bootstrap classloader.
1664 // With AllowParallelDefine flag==false, call through to define_instance_class
1665 // which will throw LinkageError: duplicate class definition.
1666 // False is the requested default.
1667 // For better performance, the class loaders should synchronize
1668 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1669 // potentially waste time reading and parsing the bytestream.
1670 // Note: VM callers should ensure consistency of k/class_name,class_loader
1671 // Be careful when modifying this code: once you have run
1672 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1673 // you need to find_and_remove it before returning.
1674 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1675 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1676 InstanceKlass* k, TRAPS) {
1677
1678 Symbol* name_h = k->name(); // passed in class_name may be null
1679 ClassLoaderData* loader_data = class_loader_data(class_loader);
1680 Dictionary* dictionary = loader_data->dictionary();
1681
1682 unsigned int d_hash = dictionary->compute_hash(name_h);
1683 int d_index = dictionary->hash_to_index(d_hash);
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 (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1694 InstanceKlass* check = find_class(d_index, 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 ((UnsyncloadClass || 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_index, 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(int index, unsigned int hash,
1792 Symbol* class_name,
1793 Dictionary* dictionary) {
1794 assert_locked_or_safepoint(SystemDictionary_lock);
1795 return dictionary->find_class(index, hash, class_name);
1796 }
1797
1798
1799 // Basic find on classes in the midst of being loaded
1800 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1801 ClassLoaderData* loader_data) {
1802 assert_locked_or_safepoint(SystemDictionary_lock);
1803 unsigned int p_hash = placeholders()->compute_hash(class_name);
1804 int p_index = placeholders()->hash_to_index(p_hash);
1805 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1806 }
1807
1808
1809 // Used for assertions and verification only
1810 // Precalculating the hash and index is an optimization because there are many lookups
1811 // before adding the class.
1812 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1813 assert_locked_or_safepoint(SystemDictionary_lock);
1814 #ifndef ASSERT
1815 guarantee(VerifyBeforeGC ||
1816 VerifyDuringGC ||
1817 VerifyBeforeExit ||
1818 VerifyDuringStartup ||
1819 VerifyAfterGC, "too expensive");
1820 #endif
1821
1822 Dictionary* dictionary = loader_data->dictionary();
1823 unsigned int d_hash = dictionary->compute_hash(class_name);
1824 int d_index = dictionary->hash_to_index(d_hash);
1825 return find_class(d_index, 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(&_system_loader_lock_obj);
1921 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1922
1923 // Do strong roots marking if the closures are the same.
1924 if (strong == weak || !ClassUnloading) {
1925 // Only the protection domain oops contain references into the heap. Iterate
1926 // over all of them.
1927 _pd_cache_table->oops_do(strong);
1928 } else {
1929 if (weak != NULL) {
1930 _pd_cache_table->oops_do(weak);
1931 }
1932 }
1933
1934 // Visit extra methods
1935 invoke_method_table()->oops_do(strong);
1936
1937 if (weak != NULL) {
1938 ResolvedMethodTable::oops_do(weak);
1939 }
1940 }
1941
1942 void SystemDictionary::oops_do(OopClosure* f) {
1943 f->do_oop(&_java_system_loader);
1944 f->do_oop(&_system_loader_lock_obj);
1945 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1946
1947 // Only the protection domain oops contain references into the heap. Iterate
1948 // over all of them.
1949 _pd_cache_table->oops_do(f);
1950
1951 // Visit extra methods
1952 invoke_method_table()->oops_do(f);
1953
1954 ResolvedMethodTable::oops_do(f);
1955 }
1956
1957 // CDS: scan and relocate all classes in the system dictionary.
1958 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1959 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1960 }
1961
1962 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1963 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1964 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1965 it->push(well_known_klass_addr((WKID)id));
1966 }
1967 }
1968
1969 void SystemDictionary::methods_do(void f(Method*)) {
1970 // Walk methods in loaded classes
1971 ClassLoaderDataGraph::methods_do(f);
1972 // Walk method handle intrinsics
1973 invoke_method_table()->methods_do(f);
1974 }
1975
1976 void SystemDictionary::remove_classes_in_error_state() {
1977 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1978 }
1979
1980 // ----------------------------------------------------------------------------
1981 // Lazily load klasses
1982
1983 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1984 // if multiple threads calling this function, only one thread will load
1985 // the class. The other threads will find the loaded version once the
1986 // class is loaded.
1987 Klass* aos = _abstract_ownable_synchronizer_klass;
1988 if (aos == NULL) {
1989 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1990 // Force a fence to prevent any read before the write completes
1991 OrderAccess::fence();
1992 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1993 }
1994 }
1995
1996 // ----------------------------------------------------------------------------
1997 // Initialization
1998
1999 void SystemDictionary::initialize(TRAPS) {
2000 // Allocate arrays
2001 _placeholders = new PlaceholderTable(_placeholder_table_size);
2002 _number_of_modifications = 0;
2003 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2004 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2005 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2006 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2007
2008 // Allocate private object used as system class loader lock
2009 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2010 // Initialize basic classes
2011 initialize_preloaded_classes(CHECK);
2012 }
2013
2014 // Compact table of directions on the initialization of klasses:
2015 static const short wk_init_info[] = {
2016 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2017 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2018 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2019 | (int)SystemDictionary::option ),
2020 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2021 #undef WK_KLASS_INIT_INFO
2022 0
2023 };
2024
2025 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2026 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2027 int info = wk_init_info[id - FIRST_WKID];
2028 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2029 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2030 InstanceKlass** klassp = &_well_known_klasses[id];
2031
2032 bool must_load;
2033 #if INCLUDE_JVMCI
2034 if (EnableJVMCI) {
2035 // If JVMCI is enabled we require its classes to be found.
2036 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2037 } else
2038 #endif
2039 {
2040 must_load = (init_opt < SystemDictionary::Opt);
2041 }
2042
2043 if (init_opt == SystemDictionary::ValhallaClasses) {
2044 if (EnableValhalla || EnableMVT) {
2045 must_load = true;
2046 } else {
2047 return false;
2048 }
2049 } else if (init_opt == SystemDictionary::MVTClasses) {
2050 if (EnableMVT) {
2051 must_load = true;
2052 } else {
2053 return false;
2054 }
2055 }
2056
2057 if ((*klassp) == NULL) {
2058 Klass* k;
2059 if (must_load) {
2060 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2061 } else {
2062 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2063 }
2064 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2065 }
2066 return ((*klassp) != NULL);
2067 }
2068
2069 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2070 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2071 for (int id = (int)start_id; id < (int)limit_id; id++) {
2072 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2073 int info = wk_init_info[id - FIRST_WKID];
2074 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2075 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2076
2077 initialize_wk_klass((WKID)id, opt, CHECK);
2078 }
2079
2080 // move the starting value forward to the limit:
2081 start_id = limit_id;
2082 }
2083
2084 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2085 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2086
2087 // Create the ModuleEntry for java.base. This call needs to be done here,
2088 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2089 ClassLoader::classLoader_init2(CHECK);
2090
2091 // Preload commonly used klasses
2092 WKID scan = FIRST_WKID;
2093 // first do Object, then String, Class
2094 #if INCLUDE_CDS
2095 if (UseSharedSpaces) {
2096 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2097 // Initialize the constant pool for the Object_class
2098 Object_klass()->constants()->restore_unshareable_info(CHECK);
2099 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2100 } else
2101 #endif
2102 {
2103 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2104 }
2105
2106 // Calculate offsets for String and Class classes since they are loaded and
2107 // can be used after this point.
2108 java_lang_String::compute_offsets();
2109 java_lang_Class::compute_offsets();
2110
2111 // Fixup mirrors for classes loaded before java.lang.Class.
2112 // These calls iterate over the objects currently in the perm gen
2113 // so calling them at this point is matters (not before when there
2114 // are fewer objects and not later after there are more objects
2115 // in the perm gen.
2116 Universe::initialize_basic_type_mirrors(CHECK);
2117 Universe::fixup_mirrors(CHECK);
2118
2119 // do a bunch more:
2120 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2121
2122 // Preload ref klasses and set reference types
2123 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2124 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2125
2126 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2127 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2128 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2129 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2130 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2131
2132 // JSR 292 classes
2133 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2134 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2135 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2136 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2137 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2138
2139 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2140 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2141 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2142 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2143 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2144 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2145 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2146 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2147 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2148 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2149
2150 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2151 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2152 _has_loadClassInternal = (method != NULL);
2153 }
2154 { // Compute whether we should use checkPackageAccess or NOT
2155 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2156 _has_checkPackageAccess = (method != NULL);
2157 }
2158 }
2159
2160 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2161 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2162 BasicType SystemDictionary::box_klass_type(Klass* k) {
2163 assert(k != NULL, "");
2164 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2165 if (_box_klasses[i] == k)
2166 return (BasicType)i;
2167 }
2168 return T_OBJECT;
2169 }
2170
2171 // Constraints on class loaders. The details of the algorithm can be
2172 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2173 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2174 // that the dictionary needs to maintain a set of contraints that
2175 // must be satisfied by all classes in the dictionary.
2176 // if defining is true, then LinkageError if already in dictionary
2177 // if initiating loader, then ok if InstanceKlass matches existing entry
2178
2179 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2180 InstanceKlass* k,
2181 Handle class_loader, bool defining,
2182 TRAPS) {
2183 const char *linkage_error1 = NULL;
2184 const char *linkage_error2 = NULL;
2185 {
2186 Symbol* name = k->name();
2187 ClassLoaderData *loader_data = class_loader_data(class_loader);
2188
2189 MutexLocker mu(SystemDictionary_lock, THREAD);
2190
2191 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2192 if (check != NULL) {
2193 // if different InstanceKlass - duplicate class definition,
2194 // else - ok, class loaded by a different thread in parallel,
2195 // we should only have found it if it was done loading and ok to use
2196 // dictionary only holds instance classes, placeholders
2197 // also holds array classes
2198
2199 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2200 if ((defining == true) || (k != check)) {
2201 linkage_error1 = "loader (instance of ";
2202 linkage_error2 = "): attempted duplicate class definition for name: \"";
2203 } else {
2204 return;
2205 }
2206 }
2207
2208 #ifdef ASSERT
2209 Symbol* ph_check = find_placeholder(name, loader_data);
2210 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2211 #endif
2212
2213 if (linkage_error1 == NULL) {
2214 if (constraints()->check_or_update(k, class_loader, name) == false) {
2215 linkage_error1 = "loader constraint violation: loader (instance of ";
2216 linkage_error2 = ") previously initiated loading for a different type with name \"";
2217 }
2218 }
2219 }
2220
2221 // Throw error now if needed (cannot throw while holding
2222 // SystemDictionary_lock because of rank ordering)
2223
2224 if (linkage_error1) {
2225 ResourceMark rm(THREAD);
2226 const char* class_loader_name = loader_name(class_loader());
2227 char* type_name = k->name()->as_C_string();
2228 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2229 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2230 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2231 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2232 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2233 }
2234 }
2235
2236
2237 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2238 // have been called.
2239 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2240 int p_index, unsigned int p_hash,
2241 InstanceKlass* k,
2242 Handle class_loader,
2243 TRAPS) {
2244 // Compile_lock prevents systemDictionary updates during compilations
2245 assert_locked_or_safepoint(Compile_lock);
2246 Symbol* name = k->name();
2247 ClassLoaderData *loader_data = class_loader_data(class_loader);
2248
2249 {
2250 MutexLocker mu1(SystemDictionary_lock, THREAD);
2251
2252 // See whether biased locking is enabled and if so set it for this
2253 // klass.
2254 // Note that this must be done past the last potential blocking
2255 // point / safepoint. We enable biased locking lazily using a
2256 // VM_Operation to iterate the SystemDictionary and installing the
2257 // biasable mark word into each InstanceKlass's prototype header.
2258 // To avoid race conditions where we accidentally miss enabling the
2259 // optimization for one class in the process of being added to the
2260 // dictionary, we must not safepoint after the test of
2261 // BiasedLocking::enabled().
2262 if (UseBiasedLocking && BiasedLocking::enabled()) {
2263 // Set biased locking bit for all loaded classes; it will be
2264 // cleared if revocation occurs too often for this type
2265 // NOTE that we must only do this when the class is initally
2266 // defined, not each time it is referenced from a new class loader
2267 if (k->class_loader() == class_loader()) {
2268 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2269 }
2270 }
2271
2272 // Make a new dictionary entry.
2273 Dictionary* dictionary = loader_data->dictionary();
2274 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2275 if (sd_check == NULL) {
2276 dictionary->add_klass(d_index, d_hash, name, k);
2277 notice_modification();
2278 }
2279 #ifdef ASSERT
2280 sd_check = find_class(d_index, d_hash, name, dictionary);
2281 assert (sd_check != NULL, "should have entry in dictionary");
2282 // Note: there may be a placeholder entry: for circularity testing
2283 // or for parallel defines
2284 #endif
2285 SystemDictionary_lock->notify_all();
2286 }
2287 }
2288
2289
2290 // Try to find a class name using the loader constraints. The
2291 // loader constraints might know about a class that isn't fully loaded
2292 // yet and these will be ignored.
2293 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2294 Symbol* class_name, Handle class_loader, TRAPS) {
2295
2296 // First see if it has been loaded directly.
2297 // Force the protection domain to be null. (This removes protection checks.)
2298 Handle no_protection_domain;
2299 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2300 no_protection_domain, CHECK_NULL);
2301 if (klass != NULL)
2302 return klass;
2303
2304 // Now look to see if it has been loaded elsewhere, and is subject to
2305 // a loader constraint that would require this loader to return the
2306 // klass that is already loaded.
2307 if (FieldType::is_array(class_name)) {
2308 // For array classes, their Klass*s are not kept in the
2309 // constraint table. The element Klass*s are.
2310 FieldArrayInfo fd;
2311 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2312 if (t != T_OBJECT && t != T_VALUETYPE) {
2313 klass = Universe::typeArrayKlassObj(t);
2314 } else {
2315 MutexLocker mu(SystemDictionary_lock, THREAD);
2316 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2317 }
2318 // If element class already loaded, allocate array klass
2319 if (klass != NULL) {
2320 klass = klass->array_klass_or_null(fd.dimension());
2321 }
2322 } else {
2323 MutexLocker mu(SystemDictionary_lock, THREAD);
2324 // Non-array classes are easy: simply check the constraint table.
2325 klass = constraints()->find_constrained_klass(class_name, class_loader);
2326 }
2327
2328 return klass;
2329 }
2330
2331
2332 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2333 Handle class_loader1,
2334 Handle class_loader2,
2335 Thread* THREAD) {
2336 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2337 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2338
2339 Symbol* constraint_name = NULL;
2340 if (!FieldType::is_array(class_name)) {
2341 constraint_name = class_name;
2342 } else {
2343 // For array classes, their Klass*s are not kept in the
2344 // constraint table. The element classes are.
2345 FieldArrayInfo fd;
2346 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2347 // primitive types always pass
2348 if (t != T_OBJECT) {
2349 return true;
2350 } else {
2351 constraint_name = fd.object_key();
2352 }
2353 }
2354
2355 Dictionary* dictionary1 = loader_data1->dictionary();
2356 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2357 int d_index1 = dictionary1->hash_to_index(d_hash1);
2358
2359 Dictionary* dictionary2 = loader_data2->dictionary();
2360 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2361 int d_index2 = dictionary2->hash_to_index(d_hash2);
2362
2363 {
2364 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2365 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2366 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2367 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2368 klass2, class_loader2);
2369 }
2370 }
2371
2372 // Add entry to resolution error table to record the error when the first
2373 // attempt to resolve a reference to a class has failed.
2374 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2375 Symbol* error, Symbol* message) {
2376 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2377 int index = resolution_errors()->hash_to_index(hash);
2378 {
2379 MutexLocker ml(SystemDictionary_lock, Thread::current());
2380 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2381 }
2382 }
2383
2384 // Delete a resolution error for RedefineClasses for a constant pool is going away
2385 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2386 resolution_errors()->delete_entry(pool);
2387 }
2388
2389 // Lookup resolution error table. Returns error if found, otherwise NULL.
2390 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2391 Symbol** message) {
2392 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2393 int index = resolution_errors()->hash_to_index(hash);
2394 {
2395 MutexLocker ml(SystemDictionary_lock, Thread::current());
2396 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2397 if (entry != NULL) {
2398 *message = entry->message();
2399 return entry->error();
2400 } else {
2401 return NULL;
2402 }
2403 }
2404 }
2405
2406
2407 // Signature constraints ensure that callers and callees agree about
2408 // the meaning of type names in their signatures. This routine is the
2409 // intake for constraints. It collects them from several places:
2410 //
2411 // * LinkResolver::resolve_method (if check_access is true) requires
2412 // that the resolving class (the caller) and the defining class of
2413 // the resolved method (the callee) agree on each type in the
2414 // method's signature.
2415 //
2416 // * LinkResolver::resolve_interface_method performs exactly the same
2417 // checks.
2418 //
2419 // * LinkResolver::resolve_field requires that the constant pool
2420 // attempting to link to a field agree with the field's defining
2421 // class about the type of the field signature.
2422 //
2423 // * klassVtable::initialize_vtable requires that, when a class
2424 // overrides a vtable entry allocated by a superclass, that the
2425 // overriding method (i.e., the callee) agree with the superclass
2426 // on each type in the method's signature.
2427 //
2428 // * klassItable::initialize_itable requires that, when a class fills
2429 // in its itables, for each non-abstract method installed in an
2430 // itable, the method (i.e., the callee) agree with the interface
2431 // on each type in the method's signature.
2432 //
2433 // All those methods have a boolean (check_access, checkconstraints)
2434 // which turns off the checks. This is used from specialized contexts
2435 // such as bootstrapping, dumping, and debugging.
2436 //
2437 // No direct constraint is placed between the class and its
2438 // supertypes. Constraints are only placed along linked relations
2439 // between callers and callees. When a method overrides or implements
2440 // an abstract method in a supertype (superclass or interface), the
2441 // constraints are placed as if the supertype were the caller to the
2442 // overriding method. (This works well, since callers to the
2443 // supertype have already established agreement between themselves and
2444 // the supertype.) As a result of all this, a class can disagree with
2445 // its supertype about the meaning of a type name, as long as that
2446 // class neither calls a relevant method of the supertype, nor is
2447 // called (perhaps via an override) from the supertype.
2448 //
2449 //
2450 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2451 //
2452 // Make sure all class components (including arrays) in the given
2453 // signature will be resolved to the same class in both loaders.
2454 // Returns the name of the type that failed a loader constraint check, or
2455 // NULL if no constraint failed. No exception except OOME is thrown.
2456 // Arrays are not added to the loader constraint table, their elements are.
2457 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2458 Handle loader1, Handle loader2,
2459 bool is_method, TRAPS) {
2460 // Nothing to do if loaders are the same.
2461 if (loader1() == loader2()) {
2462 return NULL;
2463 }
2464
2465 SignatureStream sig_strm(signature, is_method);
2466 while (!sig_strm.is_done()) {
2467 if (sig_strm.is_object()) {
2468 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2469 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2470 return sig;
2471 }
2472 }
2473 sig_strm.next();
2474 }
2475 return NULL;
2476 }
2477
2478
2479 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2480 Symbol* signature,
2481 TRAPS) {
2482 methodHandle empty;
2483 assert(MethodHandles::is_signature_polymorphic(iid) &&
2484 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2485 iid != vmIntrinsics::_invokeGeneric,
2486 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2487
2488 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2489 int index = invoke_method_table()->hash_to_index(hash);
2490 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2491 methodHandle m;
2492 if (spe == NULL || spe->method() == NULL) {
2493 spe = NULL;
2494 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2495 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2496 if (!Arguments::is_interpreter_only()) {
2497 // Generate a compiled form of the MH intrinsic.
2498 AdapterHandlerLibrary::create_native_wrapper(m);
2499 // Check if have the compiled code.
2500 if (!m->has_compiled_code()) {
2501 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2502 "Out of space in CodeCache for method handle intrinsic", empty);
2503 }
2504 }
2505 // Now grab the lock. We might have to throw away the new method,
2506 // if a racing thread has managed to install one at the same time.
2507 {
2508 MutexLocker ml(SystemDictionary_lock, THREAD);
2509 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2510 if (spe == NULL)
2511 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2512 if (spe->method() == NULL)
2513 spe->set_method(m());
2514 }
2515 }
2516
2517 assert(spe != NULL && spe->method() != NULL, "");
2518 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2519 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2520 "MH intrinsic invariant");
2521 return spe->method();
2522 }
2523
2524 // Helper for unpacking the return value from linkMethod and linkCallSite.
2525 static methodHandle unpack_method_and_appendix(Handle mname,
2526 Klass* accessing_klass,
2527 objArrayHandle appendix_box,
2528 Handle* appendix_result,
2529 TRAPS) {
2530 methodHandle empty;
2531 if (mname.not_null()) {
2532 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2533 if (m != NULL) {
2534 oop appendix = appendix_box->obj_at(0);
2535 if (TraceMethodHandles) {
2536 #ifndef PRODUCT
2537 ttyLocker ttyl;
2538 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2539 m->print();
2540 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2541 tty->cr();
2542 #endif //PRODUCT
2543 }
2544 (*appendix_result) = Handle(THREAD, appendix);
2545 // the target is stored in the cpCache and if a reference to this
2546 // MethodName is dropped we need a way to make sure the
2547 // class_loader containing this method is kept alive.
2548 // FIXME: the appendix might also preserve this dependency.
2549 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2550 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2551 return methodHandle(THREAD, m);
2552 }
2553 }
2554 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2555 return empty;
2556 }
2557
2558 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2559 Symbol* name,
2560 Symbol* signature,
2561 Klass* accessing_klass,
2562 Handle *appendix_result,
2563 Handle *method_type_result,
2564 TRAPS) {
2565 methodHandle empty;
2566 assert(THREAD->can_call_java() ,"");
2567 Handle method_type =
2568 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2569
2570 int ref_kind = JVM_REF_invokeVirtual;
2571 oop name_oop = StringTable::intern(name, CHECK_(empty));
2572 Handle name_str (THREAD, name_oop);
2573 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2574 assert(appendix_box->obj_at(0) == NULL, "");
2575
2576 // This should not happen. JDK code should take care of that.
2577 if (accessing_klass == NULL || method_type.is_null()) {
2578 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2579 }
2580
2581 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2582 JavaCallArguments args;
2583 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2584 args.push_int(ref_kind);
2585 args.push_oop(Handle(THREAD, klass->java_mirror()));
2586 args.push_oop(name_str);
2587 args.push_oop(method_type);
2588 args.push_oop(appendix_box);
2589 JavaValue result(T_OBJECT);
2590 JavaCalls::call_static(&result,
2591 SystemDictionary::MethodHandleNatives_klass(),
2592 vmSymbols::linkMethod_name(),
2593 vmSymbols::linkMethod_signature(),
2594 &args, CHECK_(empty));
2595 Handle mname(THREAD, (oop) result.get_jobject());
2596 (*method_type_result) = method_type;
2597 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2598 }
2599
2600 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2601 // We must ensure that all class loaders everywhere will reach this class, for any client.
2602 // This is a safe bet for public classes in java.lang, such as Object and String.
2603 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2604 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2605 static bool is_always_visible_class(oop mirror) {
2606 Klass* klass = java_lang_Class::as_Klass(mirror);
2607 if (klass->is_objArray_klass()) {
2608 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2609 }
2610 if (klass->is_typeArray_klass()) {
2611 return true; // primitive array
2612 }
2613 assert(klass->is_instance_klass(), "%s", klass->external_name());
2614 return klass->is_public() &&
2615 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2616 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2617 }
2618
2619 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2620 // signature, as interpreted relative to the given class loader.
2621 // Because of class loader constraints, all method handle usage must be
2622 // consistent with this loader.
2623 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2624 Klass* accessing_klass,
2625 TRAPS) {
2626 Handle empty;
2627 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2628 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2629 int index = invoke_method_table()->hash_to_index(hash);
2630 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2631 if (spe != NULL && spe->method_type() != NULL) {
2632 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2633 return Handle(THREAD, spe->method_type());
2634 } else if (!THREAD->can_call_java()) {
2635 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2636 return Handle(); // do not attempt from within compiler, unless it was cached
2637 }
2638
2639 Handle class_loader, protection_domain;
2640 if (accessing_klass != NULL) {
2641 class_loader = Handle(THREAD, accessing_klass->class_loader());
2642 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2643 }
2644 bool can_be_cached = true;
2645 int npts = ArgumentCount(signature).size();
2646 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2647 int arg = 0;
2648 Handle rt; // the return type from the signature
2649 ResourceMark rm(THREAD);
2650 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2651 oop mirror = NULL;
2652 if (can_be_cached) {
2653 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2654 mirror = ss.as_java_mirror(Handle(), Handle(),
2655 SignatureStream::ReturnNull, CHECK_(empty));
2656 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2657 // Fall back to accessing_klass context.
2658 can_be_cached = false;
2659 }
2660 }
2661 if (!can_be_cached) {
2662 // Resolve, throwing a real error if it doesn't work.
2663 mirror = ss.as_java_mirror(class_loader, protection_domain,
2664 SignatureStream::NCDFError, CHECK_(empty));
2665 }
2666 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2667 if (ss.at_return_type())
2668 rt = Handle(THREAD, mirror);
2669 else
2670 pts->obj_at_put(arg++, mirror);
2671
2672 // Check accessibility.
2673 if (ss.is_object() && accessing_klass != NULL) {
2674 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2675 mirror = NULL; // safety
2676 // Emulate ConstantPool::verify_constant_pool_resolve.
2677 if (sel_klass->is_objArray_klass())
2678 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2679 if (sel_klass->is_instance_klass()) {
2680 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2681 }
2682 }
2683 }
2684 assert(arg == npts, "");
2685
2686 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2687 JavaCallArguments args(Handle(THREAD, rt()));
2688 args.push_oop(pts);
2689 JavaValue result(T_OBJECT);
2690 JavaCalls::call_static(&result,
2691 SystemDictionary::MethodHandleNatives_klass(),
2692 vmSymbols::findMethodHandleType_name(),
2693 vmSymbols::findMethodHandleType_signature(),
2694 &args, CHECK_(empty));
2695 Handle method_type(THREAD, (oop) result.get_jobject());
2696
2697 if (can_be_cached) {
2698 // We can cache this MethodType inside the JVM.
2699 MutexLocker ml(SystemDictionary_lock, THREAD);
2700 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2701 if (spe == NULL)
2702 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2703 if (spe->method_type() == NULL) {
2704 spe->set_method_type(method_type());
2705 }
2706 }
2707
2708 // report back to the caller with the MethodType
2709 return method_type;
2710 }
2711
2712 // Ask Java code to find or construct a method handle constant.
2713 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2714 int ref_kind, //e.g., JVM_REF_invokeVirtual
2715 Klass* callee,
2716 Symbol* name_sym,
2717 Symbol* signature,
2718 TRAPS) {
2719 Handle empty;
2720 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2721 Handle type;
2722 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2723 type = find_method_handle_type(signature, caller, CHECK_(empty));
2724 } else if (caller == NULL) {
2725 // This should not happen. JDK code should take care of that.
2726 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2727 } else {
2728 ResourceMark rm(THREAD);
2729 SignatureStream ss(signature, false);
2730 if (!ss.is_done()) {
2731 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2732 Handle(THREAD, caller->protection_domain()),
2733 SignatureStream::NCDFError, CHECK_(empty));
2734 type = Handle(THREAD, mirror);
2735 ss.next();
2736 if (!ss.is_done()) type = Handle(); // error!
2737 }
2738 }
2739 if (type.is_null()) {
2740 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2741 }
2742
2743 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2744 JavaCallArguments args;
2745 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2746 args.push_int(ref_kind);
2747 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2748 args.push_oop(name);
2749 args.push_oop(type);
2750 JavaValue result(T_OBJECT);
2751 JavaCalls::call_static(&result,
2752 SystemDictionary::MethodHandleNatives_klass(),
2753 vmSymbols::linkMethodHandleConstant_name(),
2754 vmSymbols::linkMethodHandleConstant_signature(),
2755 &args, CHECK_(empty));
2756 return Handle(THREAD, (oop) result.get_jobject());
2757 }
2758
2759 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2760 // name and signature, as interpreted relative to the given class loader.
2761 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2762 Handle bootstrap_specifier,
2763 Symbol* name,
2764 Symbol* type,
2765 Handle *appendix_result,
2766 Handle *method_type_result,
2767 TRAPS) {
2768 methodHandle empty;
2769 Handle bsm, info;
2770 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2771 bsm = bootstrap_specifier;
2772 } else {
2773 assert(bootstrap_specifier->is_objArray(), "");
2774 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2775 int len = args->length();
2776 assert(len >= 1, "");
2777 bsm = Handle(THREAD, args->obj_at(0));
2778 if (len > 1) {
2779 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2780 for (int i = 1; i < len; i++)
2781 args1->obj_at_put(i-1, args->obj_at(i));
2782 info = Handle(THREAD, args1);
2783 }
2784 }
2785 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2786 "caller must supply a valid BSM");
2787
2788 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2789 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2790
2791 // This should not happen. JDK code should take care of that.
2792 if (caller == NULL || method_type.is_null()) {
2793 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2794 }
2795
2796 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2797 assert(appendix_box->obj_at(0) == NULL, "");
2798
2799 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2800 JavaCallArguments args;
2801 args.push_oop(Handle(THREAD, caller->java_mirror()));
2802 args.push_oop(bsm);
2803 args.push_oop(method_name);
2804 args.push_oop(method_type);
2805 args.push_oop(info);
2806 args.push_oop(appendix_box);
2807 JavaValue result(T_OBJECT);
2808 JavaCalls::call_static(&result,
2809 SystemDictionary::MethodHandleNatives_klass(),
2810 vmSymbols::linkCallSite_name(),
2811 vmSymbols::linkCallSite_signature(),
2812 &args, CHECK_(empty));
2813 Handle mname(THREAD, (oop) result.get_jobject());
2814 (*method_type_result) = method_type;
2815 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2816 }
2817
2818 // Protection domain cache table handling
2819
2820 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2821 return _pd_cache_table->get(protection_domain);
2822 }
2823
2824 void SystemDictionary::reorder_dictionary_for_sharing() {
2825 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2826 }
2827
2828 size_t SystemDictionary::count_bytes_for_buckets() {
2829 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2830 }
2831
2832 size_t SystemDictionary::count_bytes_for_table() {
2833 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2834 }
2835
2836 void SystemDictionary::copy_buckets(char* top, char* end) {
2837 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2838 }
2839
2840 void SystemDictionary::copy_table(char* top, char* end) {
2841 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2842 }
2843
2844 // ----------------------------------------------------------------------------
2845 void SystemDictionary::print_shared(outputStream *st) {
2846 shared_dictionary()->print_on(st);
2847 }
2848
2849 void SystemDictionary::print_on(outputStream *st) {
2850 if (shared_dictionary() != NULL) {
2851 st->print_cr("Shared Dictionary");
2852 shared_dictionary()->print_on(st);
2853 st->cr();
2854 }
2855
2856 GCMutexLocker mu(SystemDictionary_lock);
2857
2858 ClassLoaderDataGraph::print_dictionary(st);
2859
2860 // Placeholders
2861 placeholders()->print_on(st);
2862 st->cr();
2863
2864 // loader constraints - print under SD_lock
2865 constraints()->print_on(st);
2866 st->cr();
2867
2868 _pd_cache_table->print_on(st);
2869 st->cr();
2870 }
2871
2872 void SystemDictionary::verify() {
2873 guarantee(constraints() != NULL,
2874 "Verify of loader constraints failed");
2875 guarantee(placeholders()->number_of_entries() >= 0,
2876 "Verify of placeholders failed");
2877
2878 GCMutexLocker mu(SystemDictionary_lock);
2879
2880 // Verify dictionary
2881 ClassLoaderDataGraph::verify_dictionary();
2882
2883 placeholders()->verify();
2884
2885 // Verify constraint table
2886 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2887 constraints()->verify(placeholders());
2888
2889 _pd_cache_table->verify();
2890 }
2891
2892 void SystemDictionary::dump(outputStream *st, bool verbose) {
2893 assert_locked_or_safepoint(SystemDictionary_lock);
2894 if (verbose) {
2895 print_on(st);
2896 } else {
2897 if (shared_dictionary() != NULL) {
2898 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2899 }
2900 ClassLoaderDataGraph::print_dictionary_statistics(st);
2901 placeholders()->print_table_statistics(st, "Placeholder Table");
2902 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2903 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2904 }
2905 }
2906
2907 // Utility for dumping dictionaries.
2908 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2909 DCmdWithParser(output, heap),
2910 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2911 "BOOLEAN", false, "false") {
2912 _dcmdparser.add_dcmd_option(&_verbose);
2913 }
2914
2915 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2916 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2917 _verbose.value());
2918 VMThread::execute(&dumper);
2919 }
2920
2921 int SystemDictionaryDCmd::num_arguments() {
2922 ResourceMark rm;
2923 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2924 if (dcmd != NULL) {
2925 DCmdMark mark(dcmd);
2926 return dcmd->_dcmdparser.num_arguments();
2927 } else {
2928 return 0;
2929 }
2930 }
2931
2932
2933 // caller needs ResourceMark
2934 const char* SystemDictionary::loader_name(const oop loader) {
2935 return ((loader) == NULL ? "<bootloader>" :
2936 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2937 }
2938
2939 // caller needs ResourceMark
2940 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2941 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2942 SystemDictionary::loader_name(loader_data->class_loader()));
2943 }