1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/methodData.hpp"
60 #include "oops/objArrayKlass.hpp"
61 #include "oops/objArrayOop.inline.hpp"
62 #include "oops/oop.inline.hpp"
63 #include "oops/symbol.hpp"
64 #include "oops/typeArrayKlass.hpp"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/arguments_ext.hpp"
70 #include "runtime/biasedLocking.hpp"
71 #include "runtime/fieldType.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/java.hpp"
74 #include "runtime/javaCalls.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.inline.hpp"
77 #include "runtime/signature.hpp"
78 #include "services/classLoadingService.hpp"
79 #include "services/diagnosticCommand.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/tracing.hpp"
82 #include "utilities/macros.hpp"
83 #if INCLUDE_CDS
84 #include "classfile/sharedClassUtil.hpp"
85 #include "classfile/systemDictionaryShared.hpp"
86 #endif
87 #if INCLUDE_JVMCI
88 #include "jvmci/jvmciRuntime.hpp"
89 #endif
90
91 PlaceholderTable* SystemDictionary::_placeholders = NULL;
92 Dictionary* SystemDictionary::_shared_dictionary = NULL;
93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
97
98 int SystemDictionary::_number_of_modifications = 0;
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107 oop SystemDictionary::_java_platform_loader = NULL;
108
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118
119 // ----------------------------------------------------------------------------
120 // Java-level SystemLoader and PlatformLoader
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader;
124 }
125
126 oop SystemDictionary::java_platform_loader() {
127 return _java_platform_loader;
128 }
129
130 void SystemDictionary::compute_java_loaders(TRAPS) {
131 JavaValue result(T_OBJECT);
132 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
133 JavaCalls::call_static(&result,
134 class_loader_klass,
135 vmSymbols::getSystemClassLoader_name(),
136 vmSymbols::void_classloader_signature(),
137 CHECK);
138
139 _java_system_loader = (oop)result.get_jobject();
140
141 JavaCalls::call_static(&result,
142 class_loader_klass,
143 vmSymbols::getPlatformClassLoader_name(),
144 vmSymbols::void_classloader_signature(),
145 CHECK);
146
147 _java_platform_loader = (oop)result.get_jobject();
148
149 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
150 }
151
152 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
153 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
154 return ClassLoaderDataGraph::find_or_create(class_loader);
155 }
156
157 // ----------------------------------------------------------------------------
158 // Parallel class loading check
159
160 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
161 if (class_loader.is_null()) return true;
162 if (AlwaysLockClassLoader) return false;
163 return java_lang_ClassLoader::parallelCapable(class_loader());
164 }
165 // ----------------------------------------------------------------------------
166 // ParallelDefineClass flag does not apply to bootclass loader
167 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
168 if (class_loader.is_null()) return false;
169 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
170 return true;
171 }
172 return false;
173 }
174
175 // Returns true if the passed class loader is the builtin application class loader
176 // or a custom system class loader. A customer system class loader can be
177 // specified via -Djava.system.class.loader.
178 bool SystemDictionary::is_system_class_loader(oop class_loader) {
179 if (class_loader == NULL) {
180 return false;
181 }
182 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
183 class_loader == _java_system_loader);
184 }
185
186 // Returns true if the passed class loader is the platform class loader.
187 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
188 if (class_loader == NULL) {
189 return false;
190 }
191 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
192 }
193
194 // ----------------------------------------------------------------------------
195 // Resolving of classes
196
197 // Forwards to resolve_or_null
198
199 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
200 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
201 if (HAS_PENDING_EXCEPTION || klass == NULL) {
202 // can return a null klass
203 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
204 }
205 return klass;
206 }
207
208 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
209 bool throw_error,
210 Klass* klass, TRAPS) {
211 if (HAS_PENDING_EXCEPTION) {
212 // If we have a pending exception we forward it to the caller, unless throw_error is true,
213 // in which case we have to check whether the pending exception is a ClassNotFoundException,
214 // and if so convert it to a NoClassDefFoundError
215 // And chain the original ClassNotFoundException
216 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
217 ResourceMark rm(THREAD);
218 assert(klass == NULL, "Should not have result with exception pending");
219 Handle e(THREAD, PENDING_EXCEPTION);
220 CLEAR_PENDING_EXCEPTION;
221 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
222 } else {
223 return NULL;
224 }
225 }
226 // Class not found, throw appropriate error or exception depending on value of throw_error
227 if (klass == NULL) {
228 ResourceMark rm(THREAD);
229 if (throw_error) {
230 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
231 } else {
232 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
233 }
234 }
235 return klass;
236 }
237
238
239 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
240 bool throw_error, TRAPS)
241 {
242 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
243 }
244
245
246 // Forwards to resolve_instance_class_or_null
247
248 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
249 assert(THREAD->can_call_java(),
250 "can not load classes with compiler thread: class=%s, classloader=%s",
251 class_name->as_C_string(),
252 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
253 if (FieldType::is_array(class_name)) {
254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
255 } else if (FieldType::is_obj(class_name)) {
256 ResourceMark rm(THREAD);
257 // Ignore wrapping L and ;.
258 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
259 class_name->utf8_length() - 2, CHECK_NULL);
260 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
261 } else {
262 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
263 }
264 }
265
266 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
267 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
268 }
269
270 // Forwards to resolve_instance_class_or_null
271
272 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
273 Handle class_loader,
274 Handle protection_domain,
275 TRAPS) {
276 assert(FieldType::is_array(class_name), "must be array");
277 Klass* k = NULL;
278 FieldArrayInfo fd;
279 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
280 // of this call
281 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
282 if (t == T_OBJECT) {
283 // naked oop "k" is OK here -- we assign back into it
284 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
285 class_loader,
286 protection_domain,
287 CHECK_NULL);
288 if (k != NULL) {
289 k = k->array_klass(fd.dimension(), CHECK_NULL);
290 }
291 } else {
292 k = Universe::typeArrayKlassObj(t);
293 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
294 }
295 return k;
296 }
297
298
299 // Must be called for any super-class or super-interface resolution
300 // during class definition to allow class circularity checking
301 // super-interface callers:
302 // parse_interfaces - for defineClass & jvmtiRedefineClasses
303 // super-class callers:
304 // ClassFileParser - for defineClass & jvmtiRedefineClasses
305 // load_shared_class - while loading a class from shared archive
306 // resolve_instance_class_or_null:
307 // via: handle_parallel_super_load
308 // when resolving a class that has an existing placeholder with
309 // a saved superclass [i.e. a defineClass is currently in progress]
310 // if another thread is trying to resolve the class, it must do
311 // super-class checks on its own thread to catch class circularity
312 // This last call is critical in class circularity checking for cases
313 // where classloading is delegated to different threads and the
314 // classloader lock is released.
315 // Take the case: Base->Super->Base
316 // 1. If thread T1 tries to do a defineClass of class Base
317 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
318 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
319 // so it tries to load Super
320 // 3. If we load the class internally, or user classloader uses same thread
321 // loadClassFromxxx or defineClass via parseClassFile Super ...
322 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
323 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
324 // 3.4 calls resolve_super_or_fail Base
325 // 3.5 finds T1,Base -> throws class circularity
326 //OR 4. If T2 tries to resolve Super via defineClass Super ...
327 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
328 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
329 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
330 // 4.4 finds T2, Super -> throws class circularity
331 // Must be called, even if superclass is null, since this is
332 // where the placeholder entry is created which claims this
333 // thread is loading this class/classloader.
334 // Be careful when modifying this code: once you have run
335 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
336 // you need to find_and_remove it before returning.
337 // So be careful to not exit with a CHECK_ macro betweeen these calls.
338 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
339 Symbol* class_name,
340 Handle class_loader,
341 Handle protection_domain,
342 bool is_superclass,
343 TRAPS) {
344 #if INCLUDE_CDS
345 if (DumpSharedSpaces) {
346 // Special processing for CDS dump time.
347 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
348 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
349 if (k) {
350 return k;
351 }
352 }
353 #endif // INCLUDE_CDS
354
355 // Double-check, if child class is already loaded, just return super-class,interface
356 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
357 // dictionary.
358 // Make sure there's a placeholder for the *child* before resolving.
359 // Used as a claim that this thread is currently loading superclass/classloader
360 // Used here for ClassCircularity checks and also for heap verification
361 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
362 // Must check ClassCircularity before checking if super class is already loaded.
363 //
364 // We might not already have a placeholder if this child_name was
365 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
366 // the name of the class might not be known until the stream is actually
367 // parsed.
368 // Bugs 4643874, 4715493
369
370 ClassLoaderData* loader_data = class_loader_data(class_loader);
371 Dictionary* dictionary = loader_data->dictionary();
372 unsigned int d_hash = dictionary->compute_hash(child_name);
373 unsigned int p_hash = placeholders()->compute_hash(child_name);
374 int p_index = placeholders()->hash_to_index(p_hash);
375 // can't throw error holding a lock
376 bool child_already_loaded = false;
377 bool throw_circularity_error = false;
378 {
379 MutexLocker mu(SystemDictionary_lock, THREAD);
380 Klass* childk = find_class(d_hash, child_name, dictionary);
381 Klass* quicksuperk;
382 // to support // loading: if child done loading, just return superclass
383 // if class_name, & class_loader don't match:
384 // if initial define, SD update will give LinkageError
385 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
386 // so we don't throw an exception here.
387 // see: nsk redefclass014 & java.lang.instrument Instrument032
388 if ((childk != NULL ) && (is_superclass) &&
389 ((quicksuperk = childk->super()) != NULL) &&
390
391 ((quicksuperk->name() == class_name) &&
392 (quicksuperk->class_loader() == class_loader()))) {
393 return quicksuperk;
394 } else {
395 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
396 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
397 throw_circularity_error = true;
398 }
399 }
400 if (!throw_circularity_error) {
401 // Be careful not to exit resolve_super
402 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
403 }
404 }
405 if (throw_circularity_error) {
406 ResourceMark rm(THREAD);
407 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
408 }
409
410 // java.lang.Object should have been found above
411 assert(class_name != NULL, "null super class for resolving");
412 // Resolve the super class or interface, check results on return
413 Klass* superk = SystemDictionary::resolve_or_null(class_name,
414 class_loader,
415 protection_domain,
416 THREAD);
417
418 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
419 // It is no longer necessary to keep the placeholder table alive until update_dictionary
420 // or error. GC used to walk the placeholder table as strong roots.
421 // The instanceKlass is kept alive because the class loader is on the stack,
422 // which keeps the loader_data alive, as well as all instanceKlasses in
423 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
424 {
425 MutexLocker mu(SystemDictionary_lock, THREAD);
426 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
427 SystemDictionary_lock->notify_all();
428 }
429 if (HAS_PENDING_EXCEPTION || superk == NULL) {
430 // can null superk
431 superk = handle_resolution_exception(class_name, true, superk, THREAD);
432 }
433
434 return superk;
435 }
436
437 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
438 Handle class_loader,
439 Handle protection_domain,
440 TRAPS) {
441 if(!has_checkPackageAccess()) return;
442
443 // Now we have to call back to java to check if the initating class has access
444 JavaValue result(T_VOID);
445 LogTarget(Debug, protectiondomain) lt;
446 if (lt.is_enabled()) {
447 ResourceMark rm;
448 // Print out trace information
449 LogStream ls(lt);
450 ls.print_cr("Checking package access");
451 ls.print("class loader: "); class_loader()->print_value_on(&ls);
452 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
453 ls.print(" loading: "); klass->print_value_on(&ls);
454 ls.cr();
455 }
456
457 // This handle and the class_loader handle passed in keeps this class from
458 // being unloaded through several GC points.
459 // The class_loader handle passed in is the initiating loader.
460 Handle mirror(THREAD, klass->java_mirror());
461
462 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
463 JavaCalls::call_special(&result,
464 class_loader,
465 system_loader,
466 vmSymbols::checkPackageAccess_name(),
467 vmSymbols::class_protectiondomain_signature(),
468 mirror,
469 protection_domain,
470 THREAD);
471
472 if (HAS_PENDING_EXCEPTION) {
473 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
474 } else {
475 log_debug(protectiondomain)("granted");
476 }
477
478 if (HAS_PENDING_EXCEPTION) return;
479
480 // If no exception has been thrown, we have validated the protection domain
481 // Insert the protection domain of the initiating class into the set.
482 {
483 ClassLoaderData* loader_data = class_loader_data(class_loader);
484 Dictionary* dictionary = loader_data->dictionary();
485
486 Symbol* kn = klass->name();
487 unsigned int d_hash = dictionary->compute_hash(kn);
488
489 MutexLocker mu(SystemDictionary_lock, THREAD);
490 int d_index = dictionary->hash_to_index(d_hash);
491 dictionary->add_protection_domain(d_index, d_hash, klass,
492 protection_domain, THREAD);
493 }
494 }
495
496 // We only get here if this thread finds that another thread
497 // has already claimed the placeholder token for the current operation,
498 // but that other thread either never owned or gave up the
499 // object lock
500 // Waits on SystemDictionary_lock to indicate placeholder table updated
501 // On return, caller must recheck placeholder table state
502 //
503 // We only get here if
504 // 1) custom classLoader, i.e. not bootstrap classloader
505 // 2) custom classLoader has broken the class loader objectLock
506 // so another thread got here in parallel
507 //
508 // lockObject must be held.
509 // Complicated dance due to lock ordering:
510 // Must first release the classloader object lock to
511 // allow initial definer to complete the class definition
512 // and to avoid deadlock
513 // Reclaim classloader lock object with same original recursion count
514 // Must release SystemDictionary_lock after notify, since
515 // class loader lock must be claimed before SystemDictionary_lock
516 // to prevent deadlocks
517 //
518 // The notify allows applications that did an untimed wait() on
519 // the classloader object lock to not hang.
520 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
521 assert_lock_strong(SystemDictionary_lock);
522
523 bool calledholdinglock
524 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
525 assert(calledholdinglock,"must hold lock for notify");
526 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
527 ObjectSynchronizer::notifyall(lockObject, THREAD);
528 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
529 SystemDictionary_lock->wait();
530 SystemDictionary_lock->unlock();
531 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
532 SystemDictionary_lock->lock();
533 }
534
535 // If the class in is in the placeholder table, class loading is in progress
536 // For cases where the application changes threads to load classes, it
537 // is critical to ClassCircularity detection that we try loading
538 // the superclass on the same thread internally, so we do parallel
539 // super class loading here.
540 // This also is critical in cases where the original thread gets stalled
541 // even in non-circularity situations.
542 // Note: must call resolve_super_or_fail even if null super -
543 // to force placeholder entry creation for this class for circularity detection
544 // Caller must check for pending exception
545 // Returns non-null Klass* if other thread has completed load
546 // and we are done,
547 // If return null Klass* and no pending exception, the caller must load the class
548 InstanceKlass* SystemDictionary::handle_parallel_super_load(
549 Symbol* name, Symbol* superclassname, Handle class_loader,
550 Handle protection_domain, Handle lockObject, TRAPS) {
551
552 ClassLoaderData* loader_data = class_loader_data(class_loader);
553 Dictionary* dictionary = loader_data->dictionary();
554 unsigned int d_hash = dictionary->compute_hash(name);
555 unsigned int p_hash = placeholders()->compute_hash(name);
556 int p_index = placeholders()->hash_to_index(p_hash);
557
558 // superk is not used, resolve_super called for circularity check only
559 // This code is reached in two situations. One if this thread
560 // is loading the same class twice (e.g. ClassCircularity, or
561 // java.lang.instrument).
562 // The second is if another thread started the resolve_super first
563 // and has not yet finished.
564 // In both cases the original caller will clean up the placeholder
565 // entry on error.
566 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
567 superclassname,
568 class_loader,
569 protection_domain,
570 true,
571 CHECK_NULL);
572
573 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
574 // Serial class loaders and bootstrap classloader do wait for superclass loads
575 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
576 MutexLocker mu(SystemDictionary_lock, THREAD);
577 // Check if classloading completed while we were loading superclass or waiting
578 return find_class(d_hash, name, dictionary);
579 }
580
581 // must loop to both handle other placeholder updates
582 // and spurious notifications
583 bool super_load_in_progress = true;
584 PlaceholderEntry* placeholder;
585 while (super_load_in_progress) {
586 MutexLocker mu(SystemDictionary_lock, THREAD);
587 // Check if classloading completed while we were loading superclass or waiting
588 InstanceKlass* check = find_class(d_hash, name, dictionary);
589 if (check != NULL) {
590 // Klass is already loaded, so just return it
591 return check;
592 } else {
593 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
594 if (placeholder && placeholder->super_load_in_progress() ){
595 // We only get here if the application has released the
596 // classloader lock when another thread was in the middle of loading a
597 // superclass/superinterface for this class, and now
598 // this thread is also trying to load this class.
599 // To minimize surprises, the first thread that started to
600 // load a class should be the one to complete the loading
601 // with the classfile it initially expected.
602 // This logic has the current thread wait once it has done
603 // all the superclass/superinterface loading it can, until
604 // the original thread completes the class loading or fails
605 // If it completes we will use the resulting InstanceKlass
606 // which we will find below in the systemDictionary.
607 // We also get here for parallel bootstrap classloader
608 if (class_loader.is_null()) {
609 SystemDictionary_lock->wait();
610 } else {
611 double_lock_wait(lockObject, THREAD);
612 }
613 } else {
614 // If not in SD and not in PH, other thread's load must have failed
615 super_load_in_progress = false;
616 }
617 }
618 }
619 return NULL;
620 }
621
622 static void post_class_load_event(EventClassLoad* event,
623 const InstanceKlass* k,
624 const ClassLoaderData* init_cld) {
625 #if INCLUDE_TRACE
626 assert(event != NULL, "invariant");
627 assert(k != NULL, "invariant");
628 if (event->should_commit()) {
629 event->set_loadedClass(k);
630 event->set_definingClassLoader(k->class_loader_data());
631 event->set_initiatingClassLoader(init_cld);
632 event->commit();
633 }
634 #endif // INCLUDE_TRACE
635 }
636
637 static void class_define_event(InstanceKlass* k,
638 const ClassLoaderData* def_cld) {
639 #if INCLUDE_TRACE
640 EventClassDefine event;
641 if (event.should_commit()) {
642 event.set_definedClass(k);
643 event.set_definingClassLoader(def_cld);
644 event.commit();
645 }
646 #endif // INCLUDE_TRACE
647 }
648
649 // Be careful when modifying this code: once you have run
650 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
651 // you need to find_and_remove it before returning.
652 // So be careful to not exit with a CHECK_ macro betweeen these calls.
653 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
654 Handle class_loader,
655 Handle protection_domain,
656 TRAPS) {
657 assert(name != NULL && !FieldType::is_array(name) &&
658 !FieldType::is_obj(name), "invalid class name");
659
660 EventClassLoad class_load_start_event;
661
662 HandleMark hm(THREAD);
663
664 // Fix for 4474172; see evaluation for more details
665 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
666 ClassLoaderData* loader_data = register_loader(class_loader);
667 Dictionary* dictionary = loader_data->dictionary();
668 unsigned int d_hash = dictionary->compute_hash(name);
669
670 // Do lookup to see if class already exist and the protection domain
671 // has the right access
672 // This call uses find which checks protection domain already matches
673 // All subsequent calls use find_class, and set has_loaded_class so that
674 // before we return a result we call out to java to check for valid protection domain
675 // to allow returning the Klass* and add it to the pd_set if it is valid
676 {
677 Klass* probe = dictionary->find(d_hash, name, protection_domain);
678 if (probe != NULL) return probe;
679 }
680
681 // Non-bootstrap class loaders will call out to class loader and
682 // define via jvm/jni_DefineClass which will acquire the
683 // class loader object lock to protect against multiple threads
684 // defining the class in parallel by accident.
685 // This lock must be acquired here so the waiter will find
686 // any successful result in the SystemDictionary and not attempt
687 // the define.
688 // ParallelCapable Classloaders and the bootstrap classloader
689 // do not acquire lock here.
690 bool DoObjectLock = true;
691 if (is_parallelCapable(class_loader)) {
692 DoObjectLock = false;
693 }
694
695 unsigned int p_hash = placeholders()->compute_hash(name);
696 int p_index = placeholders()->hash_to_index(p_hash);
697
698 // Class is not in SystemDictionary so we have to do loading.
699 // Make sure we are synchronized on the class loader before we proceed
700 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
701 check_loader_lock_contention(lockObject, THREAD);
702 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
703
704 // Check again (after locking) if class already exist in SystemDictionary
705 bool class_has_been_loaded = false;
706 bool super_load_in_progress = false;
707 bool havesupername = false;
708 InstanceKlass* k = NULL;
709 PlaceholderEntry* placeholder;
710 Symbol* superclassname = NULL;
711
712 {
713 MutexLocker mu(SystemDictionary_lock, THREAD);
714 InstanceKlass* check = find_class(d_hash, name, dictionary);
715 if (check != NULL) {
716 // Klass is already loaded, so just return it
717 class_has_been_loaded = true;
718 k = check;
719 } else {
720 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
721 if (placeholder && placeholder->super_load_in_progress()) {
722 super_load_in_progress = true;
723 if (placeholder->havesupername() == true) {
724 superclassname = placeholder->supername();
725 havesupername = true;
726 }
727 }
728 }
729 }
730
731 // If the class is in the placeholder table, class loading is in progress
732 if (super_load_in_progress && havesupername==true) {
733 k = handle_parallel_super_load(name,
734 superclassname,
735 class_loader,
736 protection_domain,
737 lockObject, THREAD);
738 if (HAS_PENDING_EXCEPTION) {
739 return NULL;
740 }
741 if (k != NULL) {
742 class_has_been_loaded = true;
743 }
744 }
745
746 bool throw_circularity_error = false;
747 if (!class_has_been_loaded) {
748 bool load_instance_added = false;
749
750 // add placeholder entry to record loading instance class
751 // Five cases:
752 // All cases need to prevent modifying bootclasssearchpath
753 // in parallel with a classload of same classname
754 // Redefineclasses uses existence of the placeholder for the duration
755 // of the class load to prevent concurrent redefinition of not completely
756 // defined classes.
757 // case 1. traditional classloaders that rely on the classloader object lock
758 // - no other need for LOAD_INSTANCE
759 // case 2. traditional classloaders that break the classloader object lock
760 // as a deadlock workaround. Detection of this case requires that
761 // this check is done while holding the classloader object lock,
762 // and that lock is still held when calling classloader's loadClass.
763 // For these classloaders, we ensure that the first requestor
764 // completes the load and other requestors wait for completion.
765 // case 3. Bootstrap classloader - don't own objectLocker
766 // This classloader supports parallelism at the classloader level,
767 // but only allows a single load of a class/classloader pair.
768 // No performance benefit and no deadlock issues.
769 // case 4. parallelCapable user level classloaders - without objectLocker
770 // Allow parallel classloading of a class/classloader pair
771
772 {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
775 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
776 if (oldprobe) {
777 // only need check_seen_thread once, not on each loop
778 // 6341374 java/lang/Instrument with -Xcomp
779 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
780 throw_circularity_error = true;
781 } else {
782 // case 1: traditional: should never see load_in_progress.
783 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
784
785 // case 3: bootstrap classloader: prevent futile classloading,
786 // wait on first requestor
787 if (class_loader.is_null()) {
788 SystemDictionary_lock->wait();
789 } else {
790 // case 2: traditional with broken classloader lock. wait on first
791 // requestor.
792 double_lock_wait(lockObject, THREAD);
793 }
794 // Check if classloading completed while we were waiting
795 InstanceKlass* check = find_class(d_hash, name, dictionary);
796 if (check != NULL) {
797 // Klass is already loaded, so just return it
798 k = check;
799 class_has_been_loaded = true;
800 }
801 // check if other thread failed to load and cleaned up
802 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
803 }
804 }
805 }
806 }
807 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
808 // case 4: parallelCapable: allow competing threads to try
809 // LOAD_INSTANCE in parallel
810
811 if (!throw_circularity_error && !class_has_been_loaded) {
812 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
813 load_instance_added = true;
814 // For class loaders that do not acquire the classloader object lock,
815 // if they did not catch another thread holding LOAD_INSTANCE,
816 // need a check analogous to the acquire ObjectLocker/find_class
817 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
818 // one final check if the load has already completed
819 // class loaders holding the ObjectLock shouldn't find the class here
820 InstanceKlass* check = find_class(d_hash, name, dictionary);
821 if (check != NULL) {
822 // Klass is already loaded, so return it after checking/adding protection domain
823 k = check;
824 class_has_been_loaded = true;
825 }
826 }
827 }
828
829 // must throw error outside of owning lock
830 if (throw_circularity_error) {
831 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
832 ResourceMark rm(THREAD);
833 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
834 }
835
836 if (!class_has_been_loaded) {
837
838 // Do actual loading
839 k = load_instance_class(name, class_loader, THREAD);
840
841 // If everything was OK (no exceptions, no null return value), and
842 // class_loader is NOT the defining loader, do a little more bookkeeping.
843 if (!HAS_PENDING_EXCEPTION && k != NULL &&
844 k->class_loader() != class_loader()) {
845
846 check_constraints(d_hash, k, class_loader, false, THREAD);
847
848 // Need to check for a PENDING_EXCEPTION again; check_constraints
849 // can throw and doesn't use the CHECK macro.
850 if (!HAS_PENDING_EXCEPTION) {
851 { // Grabbing the Compile_lock prevents systemDictionary updates
852 // during compilations.
853 MutexLocker mu(Compile_lock, THREAD);
854 update_dictionary(d_hash, p_index, p_hash,
855 k, class_loader, THREAD);
856 }
857
858 if (JvmtiExport::should_post_class_load()) {
859 Thread *thread = THREAD;
860 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
861 JvmtiExport::post_class_load((JavaThread *) thread, k);
862 }
863 }
864 }
865 } // load_instance_class
866
867 if (load_instance_added == true) {
868 // clean up placeholder entries for LOAD_INSTANCE success or error
869 // This brackets the SystemDictionary updates for both defining
870 // and initiating loaders
871 MutexLocker mu(SystemDictionary_lock, THREAD);
872 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
873 SystemDictionary_lock->notify_all();
874 }
875 }
876
877 if (HAS_PENDING_EXCEPTION || k == NULL) {
878 return NULL;
879 }
880
881 post_class_load_event(&class_load_start_event, k, loader_data);
882
883 #ifdef ASSERT
884 {
885 ClassLoaderData* loader_data = k->class_loader_data();
886 MutexLocker mu(SystemDictionary_lock, THREAD);
887 Klass* kk = find_class(name, loader_data);
888 assert(kk == k, "should be present in dictionary");
889 }
890 #endif
891
892 // return if the protection domain in NULL
893 if (protection_domain() == NULL) return k;
894
895 // Check the protection domain has the right access
896 if (dictionary->is_valid_protection_domain(d_hash, name,
897 protection_domain)) {
898 return k;
899 }
900
901 // Verify protection domain. If it fails an exception is thrown
902 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
903
904 return k;
905 }
906
907
908 // This routine does not lock the system dictionary.
909 //
910 // Since readers don't hold a lock, we must make sure that system
911 // dictionary entries are only removed at a safepoint (when only one
912 // thread is running), and are added to in a safe way (all links must
913 // be updated in an MT-safe manner).
914 //
915 // Callers should be aware that an entry could be added just after
916 // _dictionary->bucket(index) is read here, so the caller will not see
917 // the new entry.
918
919 Klass* SystemDictionary::find(Symbol* class_name,
920 Handle class_loader,
921 Handle protection_domain,
922 TRAPS) {
923
924 // The result of this call should be consistent with the result
925 // of the call to resolve_instance_class_or_null().
926 // See evaluation 6790209 and 4474172 for more details.
927 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
928 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
929
930 if (loader_data == NULL) {
931 // If the ClassLoaderData has not been setup,
932 // then the class loader has no entries in the dictionary.
933 return NULL;
934 }
935
936 Dictionary* dictionary = loader_data->dictionary();
937 unsigned int d_hash = dictionary->compute_hash(class_name);
938 return dictionary->find(d_hash, class_name,
939 protection_domain);
940 }
941
942
943 // Look for a loaded instance or array klass by name. Do not do any loading.
944 // return NULL in case of error.
945 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
946 Handle class_loader,
947 Handle protection_domain,
948 TRAPS) {
949 Klass* k = NULL;
950 assert(class_name != NULL, "class name must be non NULL");
951
952 if (FieldType::is_array(class_name)) {
953 // The name refers to an array. Parse the name.
954 // dimension and object_key in FieldArrayInfo are assigned as a
955 // side-effect of this call
956 FieldArrayInfo fd;
957 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
958 if (t != T_OBJECT) {
959 k = Universe::typeArrayKlassObj(t);
960 } else {
961 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
962 }
963 if (k != NULL) {
964 k = k->array_klass_or_null(fd.dimension());
965 }
966 } else {
967 k = find(class_name, class_loader, protection_domain, THREAD);
968 }
969 return k;
970 }
971
972 // Note: this method is much like resolve_from_stream, but
973 // does not publish the classes via the SystemDictionary.
974 // Handles unsafe_DefineAnonymousClass and redefineclasses
975 // RedefinedClasses do not add to the class hierarchy
976 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
977 Handle class_loader,
978 Handle protection_domain,
979 ClassFileStream* st,
980 const InstanceKlass* host_klass,
981 GrowableArray<Handle>* cp_patches,
982 TRAPS) {
983
984 EventClassLoad class_load_start_event;
985
986 ClassLoaderData* loader_data;
987 if (host_klass != NULL) {
988 // Create a new CLD for anonymous class, that uses the same class loader
989 // as the host_klass
990 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
991 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
992 } else {
993 loader_data = ClassLoaderData::class_loader_data(class_loader());
994 }
995
996 assert(st != NULL, "invariant");
997 assert(st->need_verify(), "invariant");
998
999 // Parse stream and create a klass.
1000 // Note that we do this even though this klass might
1001 // already be present in the SystemDictionary, otherwise we would not
1002 // throw potential ClassFormatErrors.
1003
1004 InstanceKlass* k = KlassFactory::create_from_stream(st,
1005 class_name,
1006 loader_data,
1007 protection_domain,
1008 host_klass,
1009 cp_patches,
1010 CHECK_NULL);
1011
1012 if (host_klass != NULL && k != NULL) {
1013 // If it's anonymous, initialize it now, since nobody else will.
1014
1015 {
1016 MutexLocker mu_r(Compile_lock, THREAD);
1017
1018 // Add to class hierarchy, initialize vtables, and do possible
1019 // deoptimizations.
1020 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1021
1022 // But, do not add to dictionary.
1023
1024 // compiled code dependencies need to be validated anyway
1025 notice_modification();
1026 }
1027
1028 // Rewrite and patch constant pool here.
1029 k->link_class(CHECK_NULL);
1030 if (cp_patches != NULL) {
1031 k->constants()->patch_resolved_references(cp_patches);
1032 }
1033 k->eager_initialize(CHECK_NULL);
1034
1035 // notify jvmti
1036 if (JvmtiExport::should_post_class_load()) {
1037 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1038 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1039 }
1040
1041 post_class_load_event(&class_load_start_event, k, loader_data);
1042 }
1043 assert(host_klass != NULL || NULL == cp_patches,
1044 "cp_patches only found with host_klass");
1045
1046 return k;
1047 }
1048
1049 // Add a klass to the system from a stream (called by jni_DefineClass and
1050 // JVM_DefineClass).
1051 // Note: class_name can be NULL. In that case we do not know the name of
1052 // the class until we have parsed the stream.
1053
1054 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1055 Handle class_loader,
1056 Handle protection_domain,
1057 ClassFileStream* st,
1058 TRAPS) {
1059 #if INCLUDE_CDS
1060 ResourceMark rm(THREAD);
1061 if (DumpSharedSpaces && !class_loader.is_null() &&
1062 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1063 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1064 // class, which is used by MethodHandles).
1065 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1066 }
1067 #endif
1068
1069 HandleMark hm(THREAD);
1070
1071 // Classloaders that support parallelism, e.g. bootstrap classloader,
1072 // do not acquire lock here
1073 bool DoObjectLock = true;
1074 if (is_parallelCapable(class_loader)) {
1075 DoObjectLock = false;
1076 }
1077
1078 ClassLoaderData* loader_data = register_loader(class_loader);
1079
1080 // Make sure we are synchronized on the class loader before we proceed
1081 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1082 check_loader_lock_contention(lockObject, THREAD);
1083 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1084
1085 assert(st != NULL, "invariant");
1086
1087 // Parse the stream and create a klass.
1088 // Note that we do this even though this klass might
1089 // already be present in the SystemDictionary, otherwise we would not
1090 // throw potential ClassFormatErrors.
1091 InstanceKlass* k = NULL;
1092
1093 #if INCLUDE_CDS
1094 if (!DumpSharedSpaces) {
1095 k = SystemDictionaryShared::lookup_from_stream(class_name,
1096 class_loader,
1097 protection_domain,
1098 st,
1099 CHECK_NULL);
1100 }
1101 #endif
1102
1103 if (k == NULL) {
1104 if (st->buffer() == NULL) {
1105 return NULL;
1106 }
1107 k = KlassFactory::create_from_stream(st,
1108 class_name,
1109 loader_data,
1110 protection_domain,
1111 NULL, // host_klass
1112 NULL, // cp_patches
1113 CHECK_NULL);
1114 }
1115
1116 assert(k != NULL, "no klass created");
1117 Symbol* h_name = k->name();
1118 assert(class_name == NULL || class_name == h_name, "name mismatch");
1119
1120 // Add class just loaded
1121 // If a class loader supports parallel classloading handle parallel define requests
1122 // find_or_define_instance_class may return a different InstanceKlass
1123 if (is_parallelCapable(class_loader)) {
1124 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1125 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1126 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1127 assert(defined_k != NULL, "Should have a klass if there's no exception");
1128 loader_data->add_to_deallocate_list(k);
1129 k = defined_k;
1130 }
1131 } else {
1132 define_instance_class(k, THREAD);
1133 }
1134
1135 // If defining the class throws an exception register 'k' for cleanup.
1136 if (HAS_PENDING_EXCEPTION) {
1137 assert(k != NULL, "Must have an instance klass here!");
1138 loader_data->add_to_deallocate_list(k);
1139 return NULL;
1140 }
1141
1142 // Make sure we have an entry in the SystemDictionary on success
1143 debug_only( {
1144 MutexLocker mu(SystemDictionary_lock, THREAD);
1145
1146 Klass* check = find_class(h_name, k->class_loader_data());
1147 assert(check == k, "should be present in the dictionary");
1148 } );
1149
1150 return k;
1151 }
1152
1153 #if INCLUDE_CDS
1154 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1155 int number_of_entries) {
1156 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1157 "bad shared dictionary size.");
1158 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1159 _shared_dictionary_size, t, number_of_entries);
1160 }
1161
1162
1163 // If there is a shared dictionary, then find the entry for the
1164 // given shared system class, if any.
1165
1166 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1167 if (shared_dictionary() != NULL) {
1168 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1169 int d_index = shared_dictionary()->hash_to_index(d_hash);
1170
1171 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1172 } else {
1173 return NULL;
1174 }
1175 }
1176
1177
1178 // Load a class from the shared spaces (found through the shared system
1179 // dictionary). Force the superclass and all interfaces to be loaded.
1180 // Update the class definition to include sibling classes and no
1181 // subclasses (yet). [Classes in the shared space are not part of the
1182 // object hierarchy until loaded.]
1183
1184 InstanceKlass* SystemDictionary::load_shared_class(
1185 Symbol* class_name, Handle class_loader, TRAPS) {
1186 InstanceKlass* ik = find_shared_class(class_name);
1187 // Make sure we only return the boot class for the NULL classloader.
1188 if (ik != NULL &&
1189 ik->is_shared_boot_class() && class_loader.is_null()) {
1190 Handle protection_domain;
1191 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1192 }
1193 return NULL;
1194 }
1195
1196 // Check if a shared class can be loaded by the specific classloader:
1197 //
1198 // NULL classloader:
1199 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1200 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1201 // be defined in an unnamed module.
1202 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1203 InstanceKlass* ik,
1204 Handle class_loader, TRAPS) {
1205 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1206 "Cannot use sharing if java.base is patched");
1207 ResourceMark rm;
1208 int path_index = ik->shared_classpath_index();
1209 ClassLoaderData* loader_data = class_loader_data(class_loader);
1210 if (path_index < 0) {
1211 // path_index < 0 indicates that the class is intended for a custom loader
1212 // and should not be loaded by boot/platform/app loaders
1213 if (loader_data->is_builtin_class_loader_data()) {
1214 return false;
1215 } else {
1216 return true;
1217 }
1218 }
1219 SharedClassPathEntry* ent =
1220 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1221 if (!Universe::is_module_initialized()) {
1222 assert(ent != NULL && ent->is_modules_image(),
1223 "Loading non-bootstrap classes before the module system is initialized");
1224 assert(class_loader.is_null(), "sanity");
1225 return true;
1226 }
1227 // Get the pkg_entry from the classloader
1228 TempNewSymbol pkg_name = NULL;
1229 PackageEntry* pkg_entry = NULL;
1230 ModuleEntry* mod_entry = NULL;
1231 const char* pkg_string = NULL;
1232 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1233 if (pkg_name != NULL) {
1234 pkg_string = pkg_name->as_C_string();
1235 if (loader_data != NULL) {
1236 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1237 }
1238 if (pkg_entry != NULL) {
1239 mod_entry = pkg_entry->module();
1240 }
1241 }
1242
1243 // If the archived class is from a module that has been patched at runtime,
1244 // the class cannot be loaded from the archive.
1245 if (mod_entry != NULL && mod_entry->is_patched()) {
1246 return false;
1247 }
1248
1249 if (class_loader.is_null()) {
1250 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1251 // The NULL classloader can load archived class originated from the
1252 // "modules" jimage and the -Xbootclasspath/a. For class from the
1253 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1254 // by the NULL classloader.
1255 if (mod_entry != NULL) {
1256 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1257 // ModuleEntry's location agrees with the archived class' origination.
1258 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1259 return true; // Module class from the "module" jimage
1260 }
1261 }
1262
1263 // If the archived class is not from the "module" jimage, the class can be
1264 // loaded by the NULL classloader if
1265 //
1266 // 1. the class is from the unamed package
1267 // 2. or, the class is not from a module defined in the NULL classloader
1268 // 3. or, the class is from an unamed module
1269 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1270 // the class is from the -Xbootclasspath/a
1271 if (pkg_string == NULL ||
1272 pkg_entry == NULL ||
1273 pkg_entry->in_unnamed_module()) {
1274 assert(mod_entry == NULL ||
1275 mod_entry == loader_data->unnamed_module(),
1276 "the unnamed module is not defined in the classloader");
1277 return true;
1278 }
1279 }
1280 return false;
1281 } else {
1282 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1283 ik, class_loader, pkg_string, pkg_name,
1284 pkg_entry, mod_entry, CHECK_(false));
1285 return res;
1286 }
1287 }
1288
1289 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1290 Handle class_loader,
1291 Handle protection_domain, TRAPS) {
1292
1293 if (ik != NULL) {
1294 Symbol* class_name = ik->name();
1295
1296 bool visible = is_shared_class_visible(
1297 class_name, ik, class_loader, CHECK_NULL);
1298 if (!visible) {
1299 return NULL;
1300 }
1301
1302 // Resolve the superclass and interfaces. They must be the same
1303 // as in dump time, because the layout of <ik> depends on
1304 // the specific layout of ik->super() and ik->local_interfaces().
1305 //
1306 // If unexpected superclass or interfaces are found, we cannot
1307 // load <ik> from the shared archive.
1308
1309 if (ik->super() != NULL) {
1310 Symbol* cn = ik->super()->name();
1311 Klass *s = resolve_super_or_fail(class_name, cn,
1312 class_loader, protection_domain, true, CHECK_NULL);
1313 if (s != ik->super()) {
1314 // The dynamically resolved super class is not the same as the one we used during dump time,
1315 // so we cannot use ik.
1316 return NULL;
1317 } else {
1318 assert(s->is_shared(), "must be");
1319 }
1320 }
1321
1322 Array<Klass*>* interfaces = ik->local_interfaces();
1323 int num_interfaces = interfaces->length();
1324 for (int index = 0; index < num_interfaces; index++) {
1325 Klass* k = interfaces->at(index);
1326 Symbol* name = k->name();
1327 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1328 if (k != i) {
1329 // The dynamically resolved interface class is not the same as the one we used during dump time,
1330 // so we cannot use ik.
1331 return NULL;
1332 } else {
1333 assert(i->is_shared(), "must be");
1334 }
1335 }
1336
1337 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1338 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1339 if (new_ik != NULL) {
1340 // The class is changed by CFLH. Return the new class. The shared class is
1341 // not used.
1342 return new_ik;
1343 }
1344
1345 // Adjust methods to recover missing data. They need addresses for
1346 // interpreter entry points and their default native method address
1347 // must be reset.
1348
1349 // Updating methods must be done under a lock so multiple
1350 // threads don't update these in parallel
1351 //
1352 // Shared classes are all currently loaded by either the bootstrap or
1353 // internal parallel class loaders, so this will never cause a deadlock
1354 // on a custom class loader lock.
1355
1356 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1357 {
1358 HandleMark hm(THREAD);
1359 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1360 check_loader_lock_contention(lockObject, THREAD);
1361 ObjectLocker ol(lockObject, THREAD, true);
1362 // prohibited package check assumes all classes loaded from archive call
1363 // restore_unshareable_info which calls ik->set_package()
1364 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1365 }
1366
1367 ik->print_class_load_logging(loader_data, NULL, NULL);
1368
1369 // For boot loader, ensure that GetSystemPackage knows that a class in this
1370 // package was loaded.
1371 if (class_loader.is_null()) {
1372 int path_index = ik->shared_classpath_index();
1373 ResourceMark rm;
1374 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1375 }
1376
1377 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1378 // Only dump the classes that can be stored into CDS archive
1379 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1380 ResourceMark rm(THREAD);
1381 classlist_file->print_cr("%s", ik->name()->as_C_string());
1382 classlist_file->flush();
1383 }
1384 }
1385
1386 // notify a class loaded from shared object
1387 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1388 }
1389
1390 ik->set_has_passed_fingerprint_check(false);
1391 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1392 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1393 uint64_t cds_fp = ik->get_stored_fingerprint();
1394 if (aot_fp != 0 && aot_fp == cds_fp) {
1395 // This class matches with a class saved in an AOT library
1396 ik->set_has_passed_fingerprint_check(true);
1397 } else {
1398 ResourceMark rm;
1399 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1400 }
1401 }
1402 return ik;
1403 }
1404
1405 void SystemDictionary::clear_invoke_method_table() {
1406 SymbolPropertyEntry* spe = NULL;
1407 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1408 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1409 while (p != NULL) {
1410 spe = p;
1411 p = p->next();
1412 _invoke_method_table->free_entry(spe);
1413 }
1414 }
1415 }
1416 #endif // INCLUDE_CDS
1417
1418 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1419
1420 if (class_loader.is_null()) {
1421 ResourceMark rm;
1422 PackageEntry* pkg_entry = NULL;
1423 bool search_only_bootloader_append = false;
1424 ClassLoaderData *loader_data = class_loader_data(class_loader);
1425
1426 // Find the package in the boot loader's package entry table.
1427 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1428 if (pkg_name != NULL) {
1429 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1430 }
1431
1432 // Prior to attempting to load the class, enforce the boot loader's
1433 // visibility boundaries.
1434 if (!Universe::is_module_initialized()) {
1435 // During bootstrapping, prior to module initialization, any
1436 // class attempting to be loaded must be checked against the
1437 // java.base packages in the boot loader's PackageEntryTable.
1438 // No class outside of java.base is allowed to be loaded during
1439 // this bootstrapping window.
1440 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1441 // Class is either in the unnamed package or in
1442 // a named package within the unnamed module. Either
1443 // case is outside of java.base, do not attempt to
1444 // load the class post java.base definition. If
1445 // java.base has not been defined, let the class load
1446 // and its package will be checked later by
1447 // ModuleEntryTable::verify_javabase_packages.
1448 if (ModuleEntryTable::javabase_defined()) {
1449 return NULL;
1450 }
1451 } else {
1452 // Check that the class' package is defined within java.base.
1453 ModuleEntry* mod_entry = pkg_entry->module();
1454 Symbol* mod_entry_name = mod_entry->name();
1455 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1456 return NULL;
1457 }
1458 }
1459 } else {
1460 // After the module system has been initialized, check if the class'
1461 // package is in a module defined to the boot loader.
1462 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1463 // Class is either in the unnamed package, in a named package
1464 // within a module not defined to the boot loader or in a
1465 // a named package within the unnamed module. In all cases,
1466 // limit visibility to search for the class only in the boot
1467 // loader's append path.
1468 search_only_bootloader_append = true;
1469 }
1470 }
1471
1472 // Prior to bootstrapping's module initialization, never load a class outside
1473 // of the boot loader's module path
1474 assert(Universe::is_module_initialized() ||
1475 !search_only_bootloader_append,
1476 "Attempt to load a class outside of boot loader's module path");
1477
1478 // Search the shared system dictionary for classes preloaded into the
1479 // shared spaces.
1480 InstanceKlass* k = NULL;
1481 {
1482 #if INCLUDE_CDS
1483 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1484 k = load_shared_class(class_name, class_loader, THREAD);
1485 #endif
1486 }
1487
1488 if (k == NULL) {
1489 // Use VM class loader
1490 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1491 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1492 }
1493
1494 // find_or_define_instance_class may return a different InstanceKlass
1495 if (k != NULL) {
1496 InstanceKlass* defined_k =
1497 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1498 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1499 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1500 assert(defined_k != NULL, "Should have a klass if there's no exception");
1501 loader_data->add_to_deallocate_list(k);
1502 k = defined_k;
1503 } else if (HAS_PENDING_EXCEPTION) {
1504 loader_data->add_to_deallocate_list(k);
1505 return NULL;
1506 }
1507 }
1508 return k;
1509 } else {
1510 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1511 ResourceMark rm(THREAD);
1512
1513 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1514 JavaThread* jt = (JavaThread*) THREAD;
1515
1516 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1517 ClassLoader::perf_app_classload_selftime(),
1518 ClassLoader::perf_app_classload_count(),
1519 jt->get_thread_stat()->perf_recursion_counts_addr(),
1520 jt->get_thread_stat()->perf_timers_addr(),
1521 PerfClassTraceTime::CLASS_LOAD);
1522
1523 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1524 // Translate to external class name format, i.e., convert '/' chars to '.'
1525 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1526
1527 JavaValue result(T_OBJECT);
1528
1529 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1530
1531 // Call public unsynchronized loadClass(String) directly for all class loaders.
1532 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1533 // acquire a class-name based lock rather than the class loader object lock.
1534 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1535 JavaCalls::call_virtual(&result,
1536 class_loader,
1537 spec_klass,
1538 vmSymbols::loadClass_name(),
1539 vmSymbols::string_class_signature(),
1540 string,
1541 CHECK_NULL);
1542
1543 assert(result.get_type() == T_OBJECT, "just checking");
1544 oop obj = (oop) result.get_jobject();
1545
1546 // Primitive classes return null since forName() can not be
1547 // used to obtain any of the Class objects representing primitives or void
1548 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1549 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1550 // For user defined Java class loaders, check that the name returned is
1551 // the same as that requested. This check is done for the bootstrap
1552 // loader when parsing the class file.
1553 if (class_name == k->name()) {
1554 return k;
1555 }
1556 }
1557 // Class is not found or has the wrong name, return NULL
1558 return NULL;
1559 }
1560 }
1561
1562 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1563
1564 HandleMark hm(THREAD);
1565 ClassLoaderData* loader_data = k->class_loader_data();
1566 Handle class_loader_h(THREAD, loader_data->class_loader());
1567
1568 // for bootstrap and other parallel classloaders don't acquire lock,
1569 // use placeholder token
1570 // If a parallelCapable class loader calls define_instance_class instead of
1571 // find_or_define_instance_class to get here, we have a timing
1572 // hole with systemDictionary updates and check_constraints
1573 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1574 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1575 compute_loader_lock_object(class_loader_h, THREAD)),
1576 "define called without lock");
1577 }
1578
1579 // Check class-loading constraints. Throw exception if violation is detected.
1580 // Grabs and releases SystemDictionary_lock
1581 // The check_constraints/find_class call and update_dictionary sequence
1582 // must be "atomic" for a specific class/classloader pair so we never
1583 // define two different instanceKlasses for that class/classloader pair.
1584 // Existing classloaders will call define_instance_class with the
1585 // classloader lock held
1586 // Parallel classloaders will call find_or_define_instance_class
1587 // which will require a token to perform the define class
1588 Symbol* name_h = k->name();
1589 Dictionary* dictionary = loader_data->dictionary();
1590 unsigned int d_hash = dictionary->compute_hash(name_h);
1591 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1592
1593 // Register class just loaded with class loader (placed in Vector)
1594 // Note we do this before updating the dictionary, as this can
1595 // fail with an OutOfMemoryError (if it does, we will *not* put this
1596 // class in the dictionary and will not update the class hierarchy).
1597 // JVMTI FollowReferences needs to find the classes this way.
1598 if (k->class_loader() != NULL) {
1599 methodHandle m(THREAD, Universe::loader_addClass_method());
1600 JavaValue result(T_VOID);
1601 JavaCallArguments args(class_loader_h);
1602 args.push_oop(Handle(THREAD, k->java_mirror()));
1603 JavaCalls::call(&result, m, &args, CHECK);
1604 }
1605
1606 // Add the new class. We need recompile lock during update of CHA.
1607 {
1608 unsigned int p_hash = placeholders()->compute_hash(name_h);
1609 int p_index = placeholders()->hash_to_index(p_hash);
1610
1611 MutexLocker mu_r(Compile_lock, THREAD);
1612
1613 // Add to class hierarchy, initialize vtables, and do possible
1614 // deoptimizations.
1615 add_to_hierarchy(k, CHECK); // No exception, but can block
1616
1617 // Add to systemDictionary - so other classes can see it.
1618 // Grabs and releases SystemDictionary_lock
1619 update_dictionary(d_hash, p_index, p_hash,
1620 k, class_loader_h, THREAD);
1621 }
1622 k->eager_initialize(THREAD);
1623
1624 // notify jvmti
1625 if (JvmtiExport::should_post_class_load()) {
1626 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1627 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1628
1629 }
1630 class_define_event(k, loader_data);
1631 }
1632
1633 // Support parallel classloading
1634 // All parallel class loaders, including bootstrap classloader
1635 // lock a placeholder entry for this class/class_loader pair
1636 // to allow parallel defines of different classes for this class loader
1637 // With AllowParallelDefine flag==true, in case they do not synchronize around
1638 // FindLoadedClass/DefineClass, calls, we check for parallel
1639 // loading for them, wait if a defineClass is in progress
1640 // and return the initial requestor's results
1641 // This flag does not apply to the bootstrap classloader.
1642 // With AllowParallelDefine flag==false, call through to define_instance_class
1643 // which will throw LinkageError: duplicate class definition.
1644 // False is the requested default.
1645 // For better performance, the class loaders should synchronize
1646 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1647 // potentially waste time reading and parsing the bytestream.
1648 // Note: VM callers should ensure consistency of k/class_name,class_loader
1649 // Be careful when modifying this code: once you have run
1650 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1651 // you need to find_and_remove it before returning.
1652 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1653 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1654 InstanceKlass* k, TRAPS) {
1655
1656 Symbol* name_h = k->name(); // passed in class_name may be null
1657 ClassLoaderData* loader_data = class_loader_data(class_loader);
1658 Dictionary* dictionary = loader_data->dictionary();
1659
1660 unsigned int d_hash = dictionary->compute_hash(name_h);
1661
1662 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1663 unsigned int p_hash = placeholders()->compute_hash(name_h);
1664 int p_index = placeholders()->hash_to_index(p_hash);
1665 PlaceholderEntry* probe;
1666
1667 {
1668 MutexLocker mu(SystemDictionary_lock, THREAD);
1669 // First check if class already defined
1670 if (is_parallelDefine(class_loader)) {
1671 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1672 if (check != NULL) {
1673 return check;
1674 }
1675 }
1676
1677 // Acquire define token for this class/classloader
1678 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1679 // Wait if another thread defining in parallel
1680 // All threads wait - even those that will throw duplicate class: otherwise
1681 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1682 // if other thread has not finished updating dictionary
1683 while (probe->definer() != NULL) {
1684 SystemDictionary_lock->wait();
1685 }
1686 // Only special cases allow parallel defines and can use other thread's results
1687 // Other cases fall through, and may run into duplicate defines
1688 // caught by finding an entry in the SystemDictionary
1689 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1690 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1691 SystemDictionary_lock->notify_all();
1692 #ifdef ASSERT
1693 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1694 assert(check != NULL, "definer missed recording success");
1695 #endif
1696 return probe->instance_klass();
1697 } else {
1698 // This thread will define the class (even if earlier thread tried and had an error)
1699 probe->set_definer(THREAD);
1700 }
1701 }
1702
1703 define_instance_class(k, THREAD);
1704
1705 Handle linkage_exception = Handle(); // null handle
1706
1707 // definer must notify any waiting threads
1708 {
1709 MutexLocker mu(SystemDictionary_lock, THREAD);
1710 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1711 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1712 if (probe != NULL) {
1713 if (HAS_PENDING_EXCEPTION) {
1714 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1715 CLEAR_PENDING_EXCEPTION;
1716 } else {
1717 probe->set_instance_klass(k);
1718 }
1719 probe->set_definer(NULL);
1720 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1721 SystemDictionary_lock->notify_all();
1722 }
1723 }
1724
1725 // Can't throw exception while holding lock due to rank ordering
1726 if (linkage_exception() != NULL) {
1727 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1728 }
1729
1730 return k;
1731 }
1732
1733 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1734 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1735 if (class_loader.is_null()) {
1736 return Handle(THREAD, _system_loader_lock_obj);
1737 } else {
1738 return class_loader;
1739 }
1740 }
1741
1742 // This method is added to check how often we have to wait to grab loader
1743 // lock. The results are being recorded in the performance counters defined in
1744 // ClassLoader::_sync_systemLoaderLockContentionRate and
1745 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1746 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1747 if (!UsePerfData) {
1748 return;
1749 }
1750
1751 assert(!loader_lock.is_null(), "NULL lock object");
1752
1753 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1754 == ObjectSynchronizer::owner_other) {
1755 // contention will likely happen, so increment the corresponding
1756 // contention counter.
1757 if (loader_lock() == _system_loader_lock_obj) {
1758 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1759 } else {
1760 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1761 }
1762 }
1763 }
1764
1765 // ----------------------------------------------------------------------------
1766 // Lookup
1767
1768 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1769 Symbol* class_name,
1770 Dictionary* dictionary) {
1771 assert_locked_or_safepoint(SystemDictionary_lock);
1772 int index = dictionary->hash_to_index(hash);
1773 return dictionary->find_class(index, hash, class_name);
1774 }
1775
1776
1777 // Basic find on classes in the midst of being loaded
1778 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1779 ClassLoaderData* loader_data) {
1780 assert_locked_or_safepoint(SystemDictionary_lock);
1781 unsigned int p_hash = placeholders()->compute_hash(class_name);
1782 int p_index = placeholders()->hash_to_index(p_hash);
1783 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1784 }
1785
1786
1787 // Used for assertions and verification only
1788 // Precalculating the hash and index is an optimization because there are many lookups
1789 // before adding the class.
1790 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1791 assert_locked_or_safepoint(SystemDictionary_lock);
1792 #ifndef ASSERT
1793 guarantee(VerifyBeforeGC ||
1794 VerifyDuringGC ||
1795 VerifyBeforeExit ||
1796 VerifyDuringStartup ||
1797 VerifyAfterGC, "too expensive");
1798 #endif
1799
1800 Dictionary* dictionary = loader_data->dictionary();
1801 unsigned int d_hash = dictionary->compute_hash(class_name);
1802 return find_class(d_hash, class_name, dictionary);
1803 }
1804
1805
1806 // ----------------------------------------------------------------------------
1807 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1808 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1809 // before a new class is used.
1810
1811 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1812 assert(k != NULL, "just checking");
1813 assert_locked_or_safepoint(Compile_lock);
1814
1815 // Link into hierachy. Make sure the vtables are initialized before linking into
1816 k->append_to_sibling_list(); // add to superklass/sibling list
1817 k->process_interfaces(THREAD); // handle all "implements" declarations
1818 k->set_init_state(InstanceKlass::loaded);
1819 // Now flush all code that depended on old class hierarchy.
1820 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1821 // Also, first reinitialize vtable because it may have gotten out of synch
1822 // while the new class wasn't connected to the class hierarchy.
1823 CodeCache::flush_dependents_on(k);
1824 }
1825
1826 // ----------------------------------------------------------------------------
1827 // GC support
1828
1829 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1830 roots_oops_do(blk, NULL);
1831 }
1832
1833
1834 #ifdef ASSERT
1835 class VerifySDReachableAndLiveClosure : public OopClosure {
1836 private:
1837 BoolObjectClosure* _is_alive;
1838
1839 template <class T> void do_oop_work(T* p) {
1840 oop obj = oopDesc::load_decode_heap_oop(p);
1841 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1842 }
1843
1844 public:
1845 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1846
1847 virtual void do_oop(oop* p) { do_oop_work(p); }
1848 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1849 };
1850 #endif
1851
1852 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1853 // Note: anonymous classes are not in the SD.
1854 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1855 GCTimer* gc_timer,
1856 bool do_cleaning) {
1857
1858
1859 bool unloading_occurred;
1860 {
1861 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1862
1863 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1864 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1865 do_cleaning);
1866 }
1867
1868 if (unloading_occurred) {
1869 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1870 constraints()->purge_loader_constraints();
1871 resolution_errors()->purge_resolution_errors();
1872 }
1873
1874 {
1875 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1876 // Oops referenced by the protection domain cache table may get unreachable independently
1877 // of the class loader (eg. cached protection domain oops). So we need to
1878 // explicitly unlink them here.
1879 _pd_cache_table->unlink(is_alive);
1880
1881 #ifdef ASSERT
1882 VerifySDReachableAndLiveClosure cl(is_alive);
1883 _pd_cache_table->oops_do(&cl);
1884 #endif
1885 }
1886
1887 if (do_cleaning) {
1888 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1889 ResolvedMethodTable::unlink(is_alive);
1890 }
1891
1892 return unloading_occurred;
1893 }
1894
1895 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1896 strong->do_oop(&_java_system_loader);
1897 strong->do_oop(&_java_platform_loader);
1898 strong->do_oop(&_system_loader_lock_obj);
1899 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1900
1901 // Do strong roots marking if the closures are the same.
1902 if (strong == weak || !ClassUnloading) {
1903 // Only the protection domain oops contain references into the heap. Iterate
1904 // over all of them.
1905 _pd_cache_table->oops_do(strong);
1906 } else {
1907 if (weak != NULL) {
1908 _pd_cache_table->oops_do(weak);
1909 }
1910 }
1911
1912 // Visit extra methods
1913 invoke_method_table()->oops_do(strong);
1914
1915 if (weak != NULL) {
1916 ResolvedMethodTable::oops_do(weak);
1917 }
1918 }
1919
1920 void SystemDictionary::oops_do(OopClosure* f) {
1921 f->do_oop(&_java_system_loader);
1922 f->do_oop(&_java_platform_loader);
1923 f->do_oop(&_system_loader_lock_obj);
1924 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1925
1926 // Only the protection domain oops contain references into the heap. Iterate
1927 // over all of them.
1928 _pd_cache_table->oops_do(f);
1929
1930 // Visit extra methods
1931 invoke_method_table()->oops_do(f);
1932
1933 ResolvedMethodTable::oops_do(f);
1934 }
1935
1936 // CDS: scan and relocate all classes in the system dictionary.
1937 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1938 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1939 }
1940
1941 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1942 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1943 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1944 it->push(well_known_klass_addr((WKID)id));
1945 }
1946 }
1947
1948 void SystemDictionary::methods_do(void f(Method*)) {
1949 // Walk methods in loaded classes
1950 ClassLoaderDataGraph::methods_do(f);
1951 // Walk method handle intrinsics
1952 invoke_method_table()->methods_do(f);
1953 }
1954
1955 class RemoveClassesClosure : public CLDClosure {
1956 public:
1957 void do_cld(ClassLoaderData* cld) {
1958 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1959 cld->dictionary()->remove_classes_in_error_state();
1960 }
1961 }
1962 };
1963
1964 void SystemDictionary::remove_classes_in_error_state() {
1965 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1966 RemoveClassesClosure rcc;
1967 ClassLoaderDataGraph::cld_do(&rcc);
1968 }
1969
1970 // ----------------------------------------------------------------------------
1971 // Lazily load klasses
1972
1973 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1974 // if multiple threads calling this function, only one thread will load
1975 // the class. The other threads will find the loaded version once the
1976 // class is loaded.
1977 Klass* aos = _abstract_ownable_synchronizer_klass;
1978 if (aos == NULL) {
1979 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1980 // Force a fence to prevent any read before the write completes
1981 OrderAccess::fence();
1982 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1983 }
1984 }
1985
1986 // ----------------------------------------------------------------------------
1987 // Initialization
1988
1989 void SystemDictionary::initialize(TRAPS) {
1990 // Allocate arrays
1991 _placeholders = new PlaceholderTable(_placeholder_table_size);
1992 _number_of_modifications = 0;
1993 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1994 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1995 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1996 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1997
1998 // Allocate private object used as system class loader lock
1999 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2000 // Initialize basic classes
2001 initialize_preloaded_classes(CHECK);
2002 }
2003
2004 // Compact table of directions on the initialization of klasses:
2005 static const short wk_init_info[] = {
2006 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2007 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2008 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2009 | (int)SystemDictionary::option ),
2010 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2011 #undef WK_KLASS_INIT_INFO
2012 0
2013 };
2014
2015 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2016 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2017 int info = wk_init_info[id - FIRST_WKID];
2018 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2019 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2020 InstanceKlass** klassp = &_well_known_klasses[id];
2021
2022 bool must_load;
2023 #if INCLUDE_JVMCI
2024 if (EnableJVMCI) {
2025 // If JVMCI is enabled we require its classes to be found.
2026 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2027 } else
2028 #endif
2029 {
2030 must_load = (init_opt < SystemDictionary::Opt);
2031 }
2032
2033 if ((*klassp) == NULL) {
2034 Klass* k;
2035 if (must_load) {
2036 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2037 } else {
2038 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2039 }
2040 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2041 }
2042 return ((*klassp) != NULL);
2043 }
2044
2045 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2046 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2047 for (int id = (int)start_id; id < (int)limit_id; id++) {
2048 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2049 int info = wk_init_info[id - FIRST_WKID];
2050 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2051 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2052
2053 initialize_wk_klass((WKID)id, opt, CHECK);
2054 }
2055
2056 // move the starting value forward to the limit:
2057 start_id = limit_id;
2058 }
2059
2060 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2061 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2062
2063 // Create the ModuleEntry for java.base. This call needs to be done here,
2064 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2065 ClassLoader::classLoader_init2(CHECK);
2066
2067 // Preload commonly used klasses
2068 WKID scan = FIRST_WKID;
2069 // first do Object, then String, Class
2070 #if INCLUDE_CDS
2071 if (UseSharedSpaces) {
2072 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2073 // Initialize the constant pool for the Object_class
2074 Object_klass()->constants()->restore_unshareable_info(CHECK);
2075 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2076 } else
2077 #endif
2078 {
2079 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2080 }
2081
2082 // Calculate offsets for String and Class classes since they are loaded and
2083 // can be used after this point.
2084 java_lang_String::compute_offsets();
2085 java_lang_Class::compute_offsets();
2086
2087 // Fixup mirrors for classes loaded before java.lang.Class.
2088 // These calls iterate over the objects currently in the perm gen
2089 // so calling them at this point is matters (not before when there
2090 // are fewer objects and not later after there are more objects
2091 // in the perm gen.
2092 Universe::initialize_basic_type_mirrors(CHECK);
2093 Universe::fixup_mirrors(CHECK);
2094
2095 // do a bunch more:
2096 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2097
2098 // Preload ref klasses and set reference types
2099 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2100 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2101
2102 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2103 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2104 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2105 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2106 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2107
2108 // JSR 292 classes
2109 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2110 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2111 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2112 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2113 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2114
2115 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2116 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2117 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2118 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2119 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2120 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2121 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2122 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2123 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2124 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2125
2126 { // Compute whether we should use checkPackageAccess or NOT
2127 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2128 _has_checkPackageAccess = (method != NULL);
2129 }
2130 }
2131
2132 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2133 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2134 BasicType SystemDictionary::box_klass_type(Klass* k) {
2135 assert(k != NULL, "");
2136 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2137 if (_box_klasses[i] == k)
2138 return (BasicType)i;
2139 }
2140 return T_OBJECT;
2141 }
2142
2143 // Constraints on class loaders. The details of the algorithm can be
2144 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2145 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2146 // that the dictionary needs to maintain a set of contraints that
2147 // must be satisfied by all classes in the dictionary.
2148 // if defining is true, then LinkageError if already in dictionary
2149 // if initiating loader, then ok if InstanceKlass matches existing entry
2150
2151 void SystemDictionary::check_constraints(unsigned int d_hash,
2152 InstanceKlass* k,
2153 Handle class_loader, bool defining,
2154 TRAPS) {
2155 const char *linkage_error1 = NULL;
2156 const char *linkage_error2 = NULL;
2157 {
2158 Symbol* name = k->name();
2159 ClassLoaderData *loader_data = class_loader_data(class_loader);
2160
2161 MutexLocker mu(SystemDictionary_lock, THREAD);
2162
2163 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2164 if (check != NULL) {
2165 // if different InstanceKlass - duplicate class definition,
2166 // else - ok, class loaded by a different thread in parallel,
2167 // we should only have found it if it was done loading and ok to use
2168 // dictionary only holds instance classes, placeholders
2169 // also holds array classes
2170
2171 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2172 if ((defining == true) || (k != check)) {
2173 linkage_error1 = "loader (instance of ";
2174 linkage_error2 = "): attempted duplicate class definition for name: \"";
2175 } else {
2176 return;
2177 }
2178 }
2179
2180 #ifdef ASSERT
2181 Symbol* ph_check = find_placeholder(name, loader_data);
2182 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2183 #endif
2184
2185 if (linkage_error1 == NULL) {
2186 if (constraints()->check_or_update(k, class_loader, name) == false) {
2187 linkage_error1 = "loader constraint violation: loader (instance of ";
2188 linkage_error2 = ") previously initiated loading for a different type with name \"";
2189 }
2190 }
2191 }
2192
2193 // Throw error now if needed (cannot throw while holding
2194 // SystemDictionary_lock because of rank ordering)
2195
2196 if (linkage_error1) {
2197 ResourceMark rm(THREAD);
2198 const char* class_loader_name = loader_name(class_loader());
2199 char* type_name = k->name()->as_C_string();
2200 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2201 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2202 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2203 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2204 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2205 }
2206 }
2207
2208
2209 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2210 // have been called.
2211 void SystemDictionary::update_dictionary(unsigned int d_hash,
2212 int p_index, unsigned int p_hash,
2213 InstanceKlass* k,
2214 Handle class_loader,
2215 TRAPS) {
2216 // Compile_lock prevents systemDictionary updates during compilations
2217 assert_locked_or_safepoint(Compile_lock);
2218 Symbol* name = k->name();
2219 ClassLoaderData *loader_data = class_loader_data(class_loader);
2220
2221 {
2222 MutexLocker mu1(SystemDictionary_lock, THREAD);
2223
2224 // See whether biased locking is enabled and if so set it for this
2225 // klass.
2226 // Note that this must be done past the last potential blocking
2227 // point / safepoint. We enable biased locking lazily using a
2228 // VM_Operation to iterate the SystemDictionary and installing the
2229 // biasable mark word into each InstanceKlass's prototype header.
2230 // To avoid race conditions where we accidentally miss enabling the
2231 // optimization for one class in the process of being added to the
2232 // dictionary, we must not safepoint after the test of
2233 // BiasedLocking::enabled().
2234 if (UseBiasedLocking && BiasedLocking::enabled()) {
2235 // Set biased locking bit for all loaded classes; it will be
2236 // cleared if revocation occurs too often for this type
2237 // NOTE that we must only do this when the class is initally
2238 // defined, not each time it is referenced from a new class loader
2239 if (k->class_loader() == class_loader()) {
2240 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2241 }
2242 }
2243
2244 // Make a new dictionary entry.
2245 Dictionary* dictionary = loader_data->dictionary();
2246 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2247 if (sd_check == NULL) {
2248 dictionary->add_klass(d_hash, name, k);
2249 notice_modification();
2250 }
2251 #ifdef ASSERT
2252 sd_check = find_class(d_hash, name, dictionary);
2253 assert (sd_check != NULL, "should have entry in dictionary");
2254 // Note: there may be a placeholder entry: for circularity testing
2255 // or for parallel defines
2256 #endif
2257 SystemDictionary_lock->notify_all();
2258 }
2259 }
2260
2261
2262 // Try to find a class name using the loader constraints. The
2263 // loader constraints might know about a class that isn't fully loaded
2264 // yet and these will be ignored.
2265 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2266 Symbol* class_name, Handle class_loader, TRAPS) {
2267
2268 // First see if it has been loaded directly.
2269 // Force the protection domain to be null. (This removes protection checks.)
2270 Handle no_protection_domain;
2271 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2272 no_protection_domain, CHECK_NULL);
2273 if (klass != NULL)
2274 return klass;
2275
2276 // Now look to see if it has been loaded elsewhere, and is subject to
2277 // a loader constraint that would require this loader to return the
2278 // klass that is already loaded.
2279 if (FieldType::is_array(class_name)) {
2280 // For array classes, their Klass*s are not kept in the
2281 // constraint table. The element Klass*s are.
2282 FieldArrayInfo fd;
2283 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2284 if (t != T_OBJECT) {
2285 klass = Universe::typeArrayKlassObj(t);
2286 } else {
2287 MutexLocker mu(SystemDictionary_lock, THREAD);
2288 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2289 }
2290 // If element class already loaded, allocate array klass
2291 if (klass != NULL) {
2292 klass = klass->array_klass_or_null(fd.dimension());
2293 }
2294 } else {
2295 MutexLocker mu(SystemDictionary_lock, THREAD);
2296 // Non-array classes are easy: simply check the constraint table.
2297 klass = constraints()->find_constrained_klass(class_name, class_loader);
2298 }
2299
2300 return klass;
2301 }
2302
2303
2304 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2305 Handle class_loader1,
2306 Handle class_loader2,
2307 Thread* THREAD) {
2308 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2309 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2310
2311 Symbol* constraint_name = NULL;
2312 if (!FieldType::is_array(class_name)) {
2313 constraint_name = class_name;
2314 } else {
2315 // For array classes, their Klass*s are not kept in the
2316 // constraint table. The element classes are.
2317 FieldArrayInfo fd;
2318 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2319 // primitive types always pass
2320 if (t != T_OBJECT) {
2321 return true;
2322 } else {
2323 constraint_name = fd.object_key();
2324 }
2325 }
2326
2327 Dictionary* dictionary1 = loader_data1->dictionary();
2328 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2329
2330 Dictionary* dictionary2 = loader_data2->dictionary();
2331 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2332
2333 {
2334 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2335 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2336 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2337 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2338 klass2, class_loader2);
2339 }
2340 }
2341
2342 // Add entry to resolution error table to record the error when the first
2343 // attempt to resolve a reference to a class has failed.
2344 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2345 Symbol* error, Symbol* message) {
2346 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2347 int index = resolution_errors()->hash_to_index(hash);
2348 {
2349 MutexLocker ml(SystemDictionary_lock, Thread::current());
2350 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2351 }
2352 }
2353
2354 // Delete a resolution error for RedefineClasses for a constant pool is going away
2355 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2356 resolution_errors()->delete_entry(pool);
2357 }
2358
2359 // Lookup resolution error table. Returns error if found, otherwise NULL.
2360 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2361 Symbol** message) {
2362 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2363 int index = resolution_errors()->hash_to_index(hash);
2364 {
2365 MutexLocker ml(SystemDictionary_lock, Thread::current());
2366 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2367 if (entry != NULL) {
2368 *message = entry->message();
2369 return entry->error();
2370 } else {
2371 return NULL;
2372 }
2373 }
2374 }
2375
2376
2377 // Signature constraints ensure that callers and callees agree about
2378 // the meaning of type names in their signatures. This routine is the
2379 // intake for constraints. It collects them from several places:
2380 //
2381 // * LinkResolver::resolve_method (if check_access is true) requires
2382 // that the resolving class (the caller) and the defining class of
2383 // the resolved method (the callee) agree on each type in the
2384 // method's signature.
2385 //
2386 // * LinkResolver::resolve_interface_method performs exactly the same
2387 // checks.
2388 //
2389 // * LinkResolver::resolve_field requires that the constant pool
2390 // attempting to link to a field agree with the field's defining
2391 // class about the type of the field signature.
2392 //
2393 // * klassVtable::initialize_vtable requires that, when a class
2394 // overrides a vtable entry allocated by a superclass, that the
2395 // overriding method (i.e., the callee) agree with the superclass
2396 // on each type in the method's signature.
2397 //
2398 // * klassItable::initialize_itable requires that, when a class fills
2399 // in its itables, for each non-abstract method installed in an
2400 // itable, the method (i.e., the callee) agree with the interface
2401 // on each type in the method's signature.
2402 //
2403 // All those methods have a boolean (check_access, checkconstraints)
2404 // which turns off the checks. This is used from specialized contexts
2405 // such as bootstrapping, dumping, and debugging.
2406 //
2407 // No direct constraint is placed between the class and its
2408 // supertypes. Constraints are only placed along linked relations
2409 // between callers and callees. When a method overrides or implements
2410 // an abstract method in a supertype (superclass or interface), the
2411 // constraints are placed as if the supertype were the caller to the
2412 // overriding method. (This works well, since callers to the
2413 // supertype have already established agreement between themselves and
2414 // the supertype.) As a result of all this, a class can disagree with
2415 // its supertype about the meaning of a type name, as long as that
2416 // class neither calls a relevant method of the supertype, nor is
2417 // called (perhaps via an override) from the supertype.
2418 //
2419 //
2420 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2421 //
2422 // Make sure all class components (including arrays) in the given
2423 // signature will be resolved to the same class in both loaders.
2424 // Returns the name of the type that failed a loader constraint check, or
2425 // NULL if no constraint failed. No exception except OOME is thrown.
2426 // Arrays are not added to the loader constraint table, their elements are.
2427 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2428 Handle loader1, Handle loader2,
2429 bool is_method, TRAPS) {
2430 // Nothing to do if loaders are the same.
2431 if (loader1() == loader2()) {
2432 return NULL;
2433 }
2434
2435 SignatureStream sig_strm(signature, is_method);
2436 while (!sig_strm.is_done()) {
2437 if (sig_strm.is_object()) {
2438 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2439 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2440 return sig;
2441 }
2442 }
2443 sig_strm.next();
2444 }
2445 return NULL;
2446 }
2447
2448
2449 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2450 Symbol* signature,
2451 TRAPS) {
2452 methodHandle empty;
2453 assert(MethodHandles::is_signature_polymorphic(iid) &&
2454 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2455 iid != vmIntrinsics::_invokeGeneric,
2456 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2457
2458 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2459 int index = invoke_method_table()->hash_to_index(hash);
2460 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2461 methodHandle m;
2462 if (spe == NULL || spe->method() == NULL) {
2463 spe = NULL;
2464 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2465 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2466 if (!Arguments::is_interpreter_only()) {
2467 // Generate a compiled form of the MH intrinsic.
2468 AdapterHandlerLibrary::create_native_wrapper(m);
2469 // Check if have the compiled code.
2470 if (!m->has_compiled_code()) {
2471 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2472 "Out of space in CodeCache for method handle intrinsic", empty);
2473 }
2474 }
2475 // Now grab the lock. We might have to throw away the new method,
2476 // if a racing thread has managed to install one at the same time.
2477 {
2478 MutexLocker ml(SystemDictionary_lock, THREAD);
2479 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2480 if (spe == NULL)
2481 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2482 if (spe->method() == NULL)
2483 spe->set_method(m());
2484 }
2485 }
2486
2487 assert(spe != NULL && spe->method() != NULL, "");
2488 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2489 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2490 "MH intrinsic invariant");
2491 return spe->method();
2492 }
2493
2494 // Helper for unpacking the return value from linkMethod and linkCallSite.
2495 static methodHandle unpack_method_and_appendix(Handle mname,
2496 Klass* accessing_klass,
2497 objArrayHandle appendix_box,
2498 Handle* appendix_result,
2499 TRAPS) {
2500 methodHandle empty;
2501 if (mname.not_null()) {
2502 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2503 if (m != NULL) {
2504 oop appendix = appendix_box->obj_at(0);
2505 if (TraceMethodHandles) {
2506 #ifndef PRODUCT
2507 ttyLocker ttyl;
2508 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2509 m->print();
2510 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2511 tty->cr();
2512 #endif //PRODUCT
2513 }
2514 (*appendix_result) = Handle(THREAD, appendix);
2515 // the target is stored in the cpCache and if a reference to this
2516 // MemberName is dropped we need a way to make sure the
2517 // class_loader containing this method is kept alive.
2518 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2519 this_key->record_dependency(m->method_holder());
2520 return methodHandle(THREAD, m);
2521 }
2522 }
2523 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2524 return empty;
2525 }
2526
2527 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2528 Symbol* name,
2529 Symbol* signature,
2530 Klass* accessing_klass,
2531 Handle *appendix_result,
2532 Handle *method_type_result,
2533 TRAPS) {
2534 methodHandle empty;
2535 assert(THREAD->can_call_java() ,"");
2536 Handle method_type =
2537 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2538
2539 int ref_kind = JVM_REF_invokeVirtual;
2540 oop name_oop = StringTable::intern(name, CHECK_(empty));
2541 Handle name_str (THREAD, name_oop);
2542 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2543 assert(appendix_box->obj_at(0) == NULL, "");
2544
2545 // This should not happen. JDK code should take care of that.
2546 if (accessing_klass == NULL || method_type.is_null()) {
2547 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2548 }
2549
2550 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2551 JavaCallArguments args;
2552 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2553 args.push_int(ref_kind);
2554 args.push_oop(Handle(THREAD, klass->java_mirror()));
2555 args.push_oop(name_str);
2556 args.push_oop(method_type);
2557 args.push_oop(appendix_box);
2558 JavaValue result(T_OBJECT);
2559 JavaCalls::call_static(&result,
2560 SystemDictionary::MethodHandleNatives_klass(),
2561 vmSymbols::linkMethod_name(),
2562 vmSymbols::linkMethod_signature(),
2563 &args, CHECK_(empty));
2564 Handle mname(THREAD, (oop) result.get_jobject());
2565 (*method_type_result) = method_type;
2566 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2567 }
2568
2569 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2570 // We must ensure that all class loaders everywhere will reach this class, for any client.
2571 // This is a safe bet for public classes in java.lang, such as Object and String.
2572 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2573 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2574 static bool is_always_visible_class(oop mirror) {
2575 Klass* klass = java_lang_Class::as_Klass(mirror);
2576 if (klass->is_objArray_klass()) {
2577 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2578 }
2579 if (klass->is_typeArray_klass()) {
2580 return true; // primitive array
2581 }
2582 assert(klass->is_instance_klass(), "%s", klass->external_name());
2583 return klass->is_public() &&
2584 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2585 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2586 }
2587
2588
2589 // Return the Java mirror (java.lang.Class instance) for a single-character
2590 // descriptor. This result, when available, is the same as produced by the
2591 // heavier API point of the same name that takes a Symbol.
2592 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2593 return java_lang_Class::primitive_mirror(char2type(signature_char));
2594 }
2595
2596 // Find or construct the Java mirror (java.lang.Class instance) for a
2597 // for the given field type signature, as interpreted relative to the
2598 // given class loader. Handles primitives, void, references, arrays,
2599 // and all other reflectable types, except method types.
2600 // N.B. Code in reflection should use this entry point.
2601 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2602 Klass* accessing_klass,
2603 Handle class_loader,
2604 Handle protection_domain,
2605 SignatureStream::FailureMode failure_mode,
2606 TRAPS) {
2607 Handle empty;
2608
2609 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2610 "one or the other, or perhaps neither");
2611
2612 Symbol* type = signature;
2613
2614 // What we have here must be a valid field descriptor,
2615 // and all valid field descriptors are supported.
2616 // Produce the same java.lang.Class that reflection reports.
2617 if (type->utf8_length() == 1) {
2618
2619 // It's a primitive. (Void has a primitive mirror too.)
2620 char ch = (char) type->byte_at(0);
2621 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2622 return Handle(THREAD, find_java_mirror_for_type(ch));
2623
2624 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2625
2626 // It's a reference type.
2627 if (accessing_klass != NULL) {
2628 class_loader = Handle(THREAD, accessing_klass->class_loader());
2629 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2630 }
2631 Klass* constant_type_klass;
2632 if (failure_mode == SignatureStream::ReturnNull) {
2633 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2634 CHECK_(empty));
2635 } else {
2636 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2637 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2638 throw_error, CHECK_(empty));
2639 }
2640 if (constant_type_klass == NULL) {
2641 return Handle(); // report failure this way
2642 }
2643 Handle mirror(THREAD, constant_type_klass->java_mirror());
2644
2645 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2646 if (accessing_klass != NULL) {
2647 Klass* sel_klass = constant_type_klass;
2648 bool fold_type_to_class = true;
2649 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2650 fold_type_to_class, CHECK_(empty));
2651 }
2652
2653 return mirror;
2654
2655 }
2656
2657 // Fall through to an error.
2658 assert(false, "unsupported mirror syntax");
2659 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2660 }
2661
2662
2663 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2664 // signature, as interpreted relative to the given class loader.
2665 // Because of class loader constraints, all method handle usage must be
2666 // consistent with this loader.
2667 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2668 Klass* accessing_klass,
2669 TRAPS) {
2670 Handle empty;
2671 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2672 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2673 int index = invoke_method_table()->hash_to_index(hash);
2674 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2675 if (spe != NULL && spe->method_type() != NULL) {
2676 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2677 return Handle(THREAD, spe->method_type());
2678 } else if (!THREAD->can_call_java()) {
2679 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2680 return Handle(); // do not attempt from within compiler, unless it was cached
2681 }
2682
2683 Handle class_loader, protection_domain;
2684 if (accessing_klass != NULL) {
2685 class_loader = Handle(THREAD, accessing_klass->class_loader());
2686 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2687 }
2688 bool can_be_cached = true;
2689 int npts = ArgumentCount(signature).size();
2690 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2691 int arg = 0;
2692 Handle rt; // the return type from the signature
2693 ResourceMark rm(THREAD);
2694 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2695 oop mirror = NULL;
2696 if (can_be_cached) {
2697 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2698 mirror = ss.as_java_mirror(Handle(), Handle(),
2699 SignatureStream::ReturnNull, CHECK_(empty));
2700 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2701 // Fall back to accessing_klass context.
2702 can_be_cached = false;
2703 }
2704 }
2705 if (!can_be_cached) {
2706 // Resolve, throwing a real error if it doesn't work.
2707 mirror = ss.as_java_mirror(class_loader, protection_domain,
2708 SignatureStream::NCDFError, CHECK_(empty));
2709 }
2710 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2711 if (ss.at_return_type())
2712 rt = Handle(THREAD, mirror);
2713 else
2714 pts->obj_at_put(arg++, mirror);
2715
2716 // Check accessibility.
2717 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2718 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2719 mirror = NULL; // safety
2720 // Emulate ConstantPool::verify_constant_pool_resolve.
2721 bool fold_type_to_class = true;
2722 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2723 fold_type_to_class, CHECK_(empty));
2724 }
2725 }
2726 assert(arg == npts, "");
2727
2728 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2729 JavaCallArguments args(Handle(THREAD, rt()));
2730 args.push_oop(pts);
2731 JavaValue result(T_OBJECT);
2732 JavaCalls::call_static(&result,
2733 SystemDictionary::MethodHandleNatives_klass(),
2734 vmSymbols::findMethodHandleType_name(),
2735 vmSymbols::findMethodHandleType_signature(),
2736 &args, CHECK_(empty));
2737 Handle method_type(THREAD, (oop) result.get_jobject());
2738
2739 if (can_be_cached) {
2740 // We can cache this MethodType inside the JVM.
2741 MutexLocker ml(SystemDictionary_lock, THREAD);
2742 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2743 if (spe == NULL)
2744 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2745 if (spe->method_type() == NULL) {
2746 spe->set_method_type(method_type());
2747 }
2748 }
2749
2750 // report back to the caller with the MethodType
2751 return method_type;
2752 }
2753
2754 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2755 Klass* accessing_klass,
2756 TRAPS) {
2757 Handle empty;
2758 ResourceMark rm(THREAD);
2759 SignatureStream ss(signature, /*is_method=*/ false);
2760 if (!ss.is_done()) {
2761 Handle class_loader, protection_domain;
2762 if (accessing_klass != NULL) {
2763 class_loader = Handle(THREAD, accessing_klass->class_loader());
2764 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2765 }
2766 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2767 ss.next();
2768 if (ss.is_done()) {
2769 return Handle(THREAD, mirror);
2770 }
2771 }
2772 return empty;
2773 }
2774
2775 // Ask Java code to find or construct a method handle constant.
2776 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2777 int ref_kind, //e.g., JVM_REF_invokeVirtual
2778 Klass* callee,
2779 Symbol* name,
2780 Symbol* signature,
2781 TRAPS) {
2782 Handle empty;
2783 if (caller == NULL) {
2784 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2785 }
2786 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2787 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2788
2789 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2790 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2791 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2792 java_lang_invoke_MemberName::set_name (mname(), name_str());
2793 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2794 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2795
2796 if (ref_kind == JVM_REF_invokeVirtual &&
2797 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2798 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2799 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2800 // They are public signature polymorphic methods, but require appendix argument
2801 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2802 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2803 } else {
2804 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2805 }
2806
2807 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2808 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2809
2810 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2811 JavaCallArguments args;
2812 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2813 args.push_int(ref_kind);
2814 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2815 args.push_oop(name_str);
2816 args.push_oop(type);
2817 JavaValue result(T_OBJECT);
2818 JavaCalls::call_static(&result,
2819 SystemDictionary::MethodHandleNatives_klass(),
2820 vmSymbols::linkMethodHandleConstant_name(),
2821 vmSymbols::linkMethodHandleConstant_signature(),
2822 &args, CHECK_(empty));
2823 return Handle(THREAD, (oop) result.get_jobject());
2824 }
2825
2826 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2827 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2828 int condy_index,
2829 Handle bootstrap_specifier,
2830 Symbol* name,
2831 Symbol* type,
2832 TRAPS) {
2833 Handle empty;
2834 Handle bsm, info;
2835 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2836 bsm = bootstrap_specifier;
2837 } else {
2838 assert(bootstrap_specifier->is_objArray(), "");
2839 objArrayOop args = (objArrayOop) bootstrap_specifier();
2840 assert(args->length() == 2, "");
2841 bsm = Handle(THREAD, args->obj_at(0));
2842 info = Handle(THREAD, args->obj_at(1));
2843 }
2844 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2845 "caller must supply a valid BSM");
2846
2847 // This should not happen. JDK code should take care of that.
2848 if (caller == NULL) {
2849 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2850 }
2851
2852 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2853
2854 // Resolve the constant type in the context of the caller class
2855 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2856 CHECK_(empty));
2857
2858 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2859 JavaCallArguments args;
2860 args.push_oop(Handle(THREAD, caller->java_mirror()));
2861 args.push_int(condy_index);
2862 args.push_oop(bsm);
2863 args.push_oop(constant_name);
2864 args.push_oop(type_mirror);
2865 args.push_oop(info);
2866 JavaValue result(T_OBJECT);
2867 JavaCalls::call_static(&result,
2868 SystemDictionary::MethodHandleNatives_klass(),
2869 vmSymbols::linkDynamicConstant_name(),
2870 vmSymbols::linkDynamicConstant_signature(),
2871 &args, CHECK_(empty));
2872
2873 return Handle(THREAD, (oop) result.get_jobject());
2874 }
2875
2876 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2877 // name and signature, as interpreted relative to the given class loader.
2878 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2879 int indy_index,
2880 Handle bootstrap_specifier,
2881 Symbol* name,
2882 Symbol* type,
2883 Handle *appendix_result,
2884 Handle *method_type_result,
2885 TRAPS) {
2886 methodHandle empty;
2887 Handle bsm, info;
2888 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2889 bsm = bootstrap_specifier;
2890 } else {
2891 objArrayOop args = (objArrayOop) bootstrap_specifier();
2892 assert(args->length() == 2, "");
2893 bsm = Handle(THREAD, args->obj_at(0));
2894 info = Handle(THREAD, args->obj_at(1));
2895 }
2896 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2897 "caller must supply a valid BSM");
2898
2899 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2900 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2901
2902 // This should not happen. JDK code should take care of that.
2903 if (caller == NULL || method_type.is_null()) {
2904 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2905 }
2906
2907 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2908 assert(appendix_box->obj_at(0) == NULL, "");
2909
2910 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2911 JavaCallArguments args;
2912 args.push_oop(Handle(THREAD, caller->java_mirror()));
2913 args.push_int(indy_index);
2914 args.push_oop(bsm);
2915 args.push_oop(method_name);
2916 args.push_oop(method_type);
2917 args.push_oop(info);
2918 args.push_oop(appendix_box);
2919 JavaValue result(T_OBJECT);
2920 JavaCalls::call_static(&result,
2921 SystemDictionary::MethodHandleNatives_klass(),
2922 vmSymbols::linkCallSite_name(),
2923 vmSymbols::linkCallSite_signature(),
2924 &args, CHECK_(empty));
2925 Handle mname(THREAD, (oop) result.get_jobject());
2926 (*method_type_result) = method_type;
2927 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2928 }
2929
2930 // Protection domain cache table handling
2931
2932 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2933 return _pd_cache_table->get(protection_domain);
2934 }
2935
2936 #if INCLUDE_CDS
2937 void SystemDictionary::reorder_dictionary_for_sharing() {
2938 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2939 }
2940 #endif
2941
2942 size_t SystemDictionary::count_bytes_for_buckets() {
2943 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2944 }
2945
2946 size_t SystemDictionary::count_bytes_for_table() {
2947 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2948 }
2949
2950 void SystemDictionary::copy_buckets(char* top, char* end) {
2951 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2952 }
2953
2954 void SystemDictionary::copy_table(char* top, char* end) {
2955 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2956 }
2957
2958 // ----------------------------------------------------------------------------
2959 void SystemDictionary::print_shared(outputStream *st) {
2960 shared_dictionary()->print_on(st);
2961 }
2962
2963 void SystemDictionary::print_on(outputStream *st) {
2964 if (shared_dictionary() != NULL) {
2965 st->print_cr("Shared Dictionary");
2966 shared_dictionary()->print_on(st);
2967 st->cr();
2968 }
2969
2970 GCMutexLocker mu(SystemDictionary_lock);
2971
2972 ClassLoaderDataGraph::print_dictionary(st);
2973
2974 // Placeholders
2975 placeholders()->print_on(st);
2976 st->cr();
2977
2978 // loader constraints - print under SD_lock
2979 constraints()->print_on(st);
2980 st->cr();
2981
2982 _pd_cache_table->print_on(st);
2983 st->cr();
2984 }
2985
2986 void SystemDictionary::verify() {
2987 guarantee(constraints() != NULL,
2988 "Verify of loader constraints failed");
2989 guarantee(placeholders()->number_of_entries() >= 0,
2990 "Verify of placeholders failed");
2991
2992 GCMutexLocker mu(SystemDictionary_lock);
2993
2994 // Verify dictionary
2995 ClassLoaderDataGraph::verify_dictionary();
2996
2997 placeholders()->verify();
2998
2999 // Verify constraint table
3000 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3001 constraints()->verify(placeholders());
3002
3003 _pd_cache_table->verify();
3004 }
3005
3006 void SystemDictionary::dump(outputStream *st, bool verbose) {
3007 assert_locked_or_safepoint(SystemDictionary_lock);
3008 if (verbose) {
3009 print_on(st);
3010 } else {
3011 if (shared_dictionary() != NULL) {
3012 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3013 }
3014 ClassLoaderDataGraph::print_dictionary_statistics(st);
3015 placeholders()->print_table_statistics(st, "Placeholder Table");
3016 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3017 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3018 }
3019 }
3020
3021 // Utility for dumping dictionaries.
3022 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3023 DCmdWithParser(output, heap),
3024 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3025 "BOOLEAN", false, "false") {
3026 _dcmdparser.add_dcmd_option(&_verbose);
3027 }
3028
3029 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3030 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3031 _verbose.value());
3032 VMThread::execute(&dumper);
3033 }
3034
3035 int SystemDictionaryDCmd::num_arguments() {
3036 ResourceMark rm;
3037 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3038 if (dcmd != NULL) {
3039 DCmdMark mark(dcmd);
3040 return dcmd->_dcmdparser.num_arguments();
3041 } else {
3042 return 0;
3043 }
3044 }
3045
3046 class CombineDictionariesClosure : public CLDClosure {
3047 private:
3048 Dictionary* _master_dictionary;
3049 public:
3050 CombineDictionariesClosure(Dictionary* master_dictionary) :
3051 _master_dictionary(master_dictionary) {}
3052 void do_cld(ClassLoaderData* cld) {
3053 ResourceMark rm;
3054 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3055 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3056 Dictionary* curr_dictionary = cld->dictionary();
3057 DictionaryEntry* p = curr_dictionary->bucket(i);
3058 while (p != NULL) {
3059 Symbol* name = p->instance_klass()->name();
3060 unsigned int d_hash = _master_dictionary->compute_hash(name);
3061 int d_index = _master_dictionary->hash_to_index(d_hash);
3062 DictionaryEntry* next = p->next();
3063 if (p->literal()->class_loader_data() != cld) {
3064 // This is an initiating class loader entry; don't use it
3065 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3066 curr_dictionary->free_entry(p);
3067 } else {
3068 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3069 curr_dictionary->unlink_entry(p);
3070 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3071 _master_dictionary->add_entry(d_index, p);
3072 }
3073 p = next;
3074 }
3075 *curr_dictionary->bucket_addr(i) = NULL;
3076 }
3077 }
3078 }
3079 };
3080
3081 // Combining platform and system loader dictionaries into boot loader dictionaries.
3082 // During run time, we only have one shared dictionary.
3083 void SystemDictionary::combine_shared_dictionaries() {
3084 assert(DumpSharedSpaces, "dump time only");
3085 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3086 CombineDictionariesClosure cdc(master_dictionary);
3087 ClassLoaderDataGraph::cld_do(&cdc);
3088
3089 // These tables are no longer valid or necessary. Keeping them around will
3090 // cause SystemDictionary::verify() to fail. Let's empty them.
3091 _placeholders = new PlaceholderTable(_placeholder_table_size);
3092 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3093
3094 NOT_PRODUCT(SystemDictionary::verify());
3095 }
3096
3097 // caller needs ResourceMark
3098 const char* SystemDictionary::loader_name(const oop loader) {
3099 return ((loader) == NULL ? "<bootloader>" :
3100 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3101 }
3102
3103 // caller needs ResourceMark
3104 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3105 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3106 SystemDictionary::loader_name(loader_data->class_loader()));
3107 }