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