1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/access.inline.hpp"
57 #include "oops/instanceKlass.hpp"
58 #include "oops/instanceRefKlass.hpp"
59 #include "oops/klass.inline.hpp"
60 #include "oops/method.inline.hpp"
61 #include "oops/methodData.hpp"
62 #include "oops/objArrayKlass.hpp"
63 #include "oops/objArrayOop.inline.hpp"
64 #include "oops/oop.inline.hpp"
65 #include "oops/symbol.hpp"
66 #include "oops/typeArrayKlass.hpp"
67 #include "prims/jvmtiEnvBase.hpp"
68 #include "prims/resolvedMethodTable.hpp"
69 #include "prims/methodHandles.hpp"
70 #include "runtime/arguments.hpp"
71 #include "runtime/arguments_ext.hpp"
72 #include "runtime/biasedLocking.hpp"
73 #include "runtime/fieldType.hpp"
74 #include "runtime/handles.inline.hpp"
75 #include "runtime/java.hpp"
76 #include "runtime/javaCalls.hpp"
77 #include "runtime/mutexLocker.hpp"
78 #include "runtime/orderAccess.inline.hpp"
79 #include "runtime/sharedRuntime.hpp"
80 #include "runtime/signature.hpp"
81 #include "services/classLoadingService.hpp"
82 #include "services/diagnosticCommand.hpp"
83 #include "services/threadService.hpp"
84 #include "trace/tracing.hpp"
85 #include "utilities/macros.hpp"
86 #if INCLUDE_CDS
87 #include "classfile/sharedClassUtil.hpp"
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JVMCI
91 #include "jvmci/jvmciRuntime.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 Dictionary* SystemDictionary::_shared_dictionary = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 int SystemDictionary::_number_of_modifications = 0;
102 oop SystemDictionary::_system_loader_lock_obj = NULL;
103
104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
105 = { NULL /*, NULL...*/ };
106
107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
108
109 oop SystemDictionary::_java_system_loader = NULL;
110 oop SystemDictionary::_java_platform_loader = NULL;
111
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // lazily initialized klass variables
115 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
116
117 // Default ProtectionDomainCacheSize value
118
119 const int defaultProtectionDomainCacheSize = 1009;
120
121
122 // ----------------------------------------------------------------------------
123 // Java-level SystemLoader and PlatformLoader
124
125 oop SystemDictionary::java_system_loader() {
126 return _java_system_loader;
127 }
128
129 oop SystemDictionary::java_platform_loader() {
130 return _java_platform_loader;
131 }
132
133 void SystemDictionary::compute_java_loaders(TRAPS) {
134 JavaValue result(T_OBJECT);
135 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
136 JavaCalls::call_static(&result,
137 class_loader_klass,
138 vmSymbols::getSystemClassLoader_name(),
139 vmSymbols::void_classloader_signature(),
140 CHECK);
141
142 _java_system_loader = (oop)result.get_jobject();
143
144 JavaCalls::call_static(&result,
145 class_loader_klass,
146 vmSymbols::getPlatformClassLoader_name(),
147 vmSymbols::void_classloader_signature(),
148 CHECK);
149
150 _java_platform_loader = (oop)result.get_jobject();
151
152 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
153 }
154
155 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
156 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
157 return ClassLoaderDataGraph::find_or_create(class_loader);
158 }
159
160 // ----------------------------------------------------------------------------
161 // Parallel class loading check
162
163 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
164 if (class_loader.is_null()) return true;
165 if (AlwaysLockClassLoader) return false;
166 return java_lang_ClassLoader::parallelCapable(class_loader());
167 }
168 // ----------------------------------------------------------------------------
169 // ParallelDefineClass flag does not apply to bootclass loader
170 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
171 if (class_loader.is_null()) return false;
172 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
173 return true;
174 }
175 return false;
176 }
177
178 // Returns true if the passed class loader is the builtin application class loader
179 // or a custom system class loader. A customer system class loader can be
180 // specified via -Djava.system.class.loader.
181 bool SystemDictionary::is_system_class_loader(oop class_loader) {
182 if (class_loader == NULL) {
183 return false;
184 }
185 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
186 class_loader == _java_system_loader);
187 }
188
189 // Returns true if the passed class loader is the platform class loader.
190 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
191 if (class_loader == NULL) {
192 return false;
193 }
194 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
195 }
196
197 // ----------------------------------------------------------------------------
198 // Resolving of classes
199
200 // Forwards to resolve_or_null
201
202 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
203 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
204 if (HAS_PENDING_EXCEPTION || klass == NULL) {
205 // can return a null klass
206 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
207 }
208 return klass;
209 }
210
211 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
212 bool throw_error,
213 Klass* klass, TRAPS) {
214 if (HAS_PENDING_EXCEPTION) {
215 // If we have a pending exception we forward it to the caller, unless throw_error is true,
216 // in which case we have to check whether the pending exception is a ClassNotFoundException,
217 // and if so convert it to a NoClassDefFoundError
218 // And chain the original ClassNotFoundException
219 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
220 ResourceMark rm(THREAD);
221 assert(klass == NULL, "Should not have result with exception pending");
222 Handle e(THREAD, PENDING_EXCEPTION);
223 CLEAR_PENDING_EXCEPTION;
224 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
225 } else {
226 return NULL;
227 }
228 }
229 // Class not found, throw appropriate error or exception depending on value of throw_error
230 if (klass == NULL) {
231 ResourceMark rm(THREAD);
232 if (throw_error) {
233 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
234 } else {
235 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
236 }
237 }
238 return klass;
239 }
240
241
242 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
243 bool throw_error, TRAPS)
244 {
245 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
246 }
247
248
249 // Forwards to resolve_instance_class_or_null
250
251 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
252 assert(THREAD->can_call_java(),
253 "can not load classes with compiler thread: class=%s, classloader=%s",
254 class_name->as_C_string(),
255 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
256 if (FieldType::is_array(class_name)) {
257 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
258 } else if (FieldType::is_obj(class_name)) {
259 ResourceMark rm(THREAD);
260 // Ignore wrapping L and ;.
261 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
262 class_name->utf8_length() - 2, CHECK_NULL);
263 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
264 } else {
265 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
266 }
267 }
268
269 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
270 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
271 }
272
273 // Forwards to resolve_instance_class_or_null
274
275 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
276 Handle class_loader,
277 Handle protection_domain,
278 TRAPS) {
279 assert(FieldType::is_array(class_name), "must be array");
280 Klass* k = NULL;
281 FieldArrayInfo fd;
282 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
283 // of this call
284 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
285 if (t == T_OBJECT) {
286 // naked oop "k" is OK here -- we assign back into it
287 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
288 class_loader,
289 protection_domain,
290 CHECK_NULL);
291 if (k != NULL) {
292 k = k->array_klass(fd.dimension(), CHECK_NULL);
293 }
294 } else {
295 k = Universe::typeArrayKlassObj(t);
296 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
297 }
298 return k;
299 }
300
301
302 // Must be called for any super-class or super-interface resolution
303 // during class definition to allow class circularity checking
304 // super-interface callers:
305 // parse_interfaces - for defineClass & jvmtiRedefineClasses
306 // super-class callers:
307 // ClassFileParser - for defineClass & jvmtiRedefineClasses
308 // load_shared_class - while loading a class from shared archive
309 // resolve_instance_class_or_null:
310 // via: handle_parallel_super_load
311 // when resolving a class that has an existing placeholder with
312 // a saved superclass [i.e. a defineClass is currently in progress]
313 // if another thread is trying to resolve the class, it must do
314 // super-class checks on its own thread to catch class circularity
315 // This last call is critical in class circularity checking for cases
316 // where classloading is delegated to different threads and the
317 // classloader lock is released.
318 // Take the case: Base->Super->Base
319 // 1. If thread T1 tries to do a defineClass of class Base
320 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
321 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
322 // so it tries to load Super
323 // 3. If we load the class internally, or user classloader uses same thread
324 // loadClassFromxxx or defineClass via parseClassFile Super ...
325 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
326 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
327 // 3.4 calls resolve_super_or_fail Base
328 // 3.5 finds T1,Base -> throws class circularity
329 //OR 4. If T2 tries to resolve Super via defineClass Super ...
330 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
331 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
332 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
333 // 4.4 finds T2, Super -> throws class circularity
334 // Must be called, even if superclass is null, since this is
335 // where the placeholder entry is created which claims this
336 // thread is loading this class/classloader.
337 // Be careful when modifying this code: once you have run
338 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
339 // you need to find_and_remove it before returning.
340 // So be careful to not exit with a CHECK_ macro betweeen these calls.
341 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
342 Symbol* class_name,
343 Handle class_loader,
344 Handle protection_domain,
345 bool is_superclass,
346 TRAPS) {
347 #if INCLUDE_CDS
348 if (DumpSharedSpaces) {
349 // Special processing for CDS dump time.
350 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
351 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
352 if (k) {
353 return k;
354 }
355 }
356 #endif // INCLUDE_CDS
357
358 // Double-check, if child class is already loaded, just return super-class,interface
359 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
360 // dictionary.
361 // Make sure there's a placeholder for the *child* before resolving.
362 // Used as a claim that this thread is currently loading superclass/classloader
363 // Used here for ClassCircularity checks and also for heap verification
364 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
365 // Must check ClassCircularity before checking if super class is already loaded.
366 //
367 // We might not already have a placeholder if this child_name was
368 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
369 // the name of the class might not be known until the stream is actually
370 // parsed.
371 // Bugs 4643874, 4715493
372
373 ClassLoaderData* loader_data = class_loader_data(class_loader);
374 Dictionary* dictionary = loader_data->dictionary();
375 unsigned int d_hash = dictionary->compute_hash(child_name);
376 unsigned int p_hash = placeholders()->compute_hash(child_name);
377 int p_index = placeholders()->hash_to_index(p_hash);
378 // can't throw error holding a lock
379 bool child_already_loaded = false;
380 bool throw_circularity_error = false;
381 {
382 MutexLocker mu(SystemDictionary_lock, THREAD);
383 Klass* childk = find_class(d_hash, child_name, dictionary);
384 Klass* quicksuperk;
385 // to support // loading: if child done loading, just return superclass
386 // if class_name, & class_loader don't match:
387 // if initial define, SD update will give LinkageError
388 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
389 // so we don't throw an exception here.
390 // see: nsk redefclass014 & java.lang.instrument Instrument032
391 if ((childk != NULL ) && (is_superclass) &&
392 ((quicksuperk = childk->super()) != NULL) &&
393
394 ((quicksuperk->name() == class_name) &&
395 (quicksuperk->class_loader() == class_loader()))) {
396 return quicksuperk;
397 } else {
398 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
399 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
400 throw_circularity_error = true;
401 }
402 }
403 if (!throw_circularity_error) {
404 // Be careful not to exit resolve_super
405 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
406 }
407 }
408 if (throw_circularity_error) {
409 ResourceMark rm(THREAD);
410 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
411 }
412
413 // java.lang.Object should have been found above
414 assert(class_name != NULL, "null super class for resolving");
415 // Resolve the super class or interface, check results on return
416 Klass* superk = SystemDictionary::resolve_or_null(class_name,
417 class_loader,
418 protection_domain,
419 THREAD);
420
421 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
422 // It is no longer necessary to keep the placeholder table alive until update_dictionary
423 // or error. GC used to walk the placeholder table as strong roots.
424 // The instanceKlass is kept alive because the class loader is on the stack,
425 // which keeps the loader_data alive, as well as all instanceKlasses in
426 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
427 {
428 MutexLocker mu(SystemDictionary_lock, THREAD);
429 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
430 SystemDictionary_lock->notify_all();
431 }
432 if (HAS_PENDING_EXCEPTION || superk == NULL) {
433 // can null superk
434 superk = handle_resolution_exception(class_name, true, superk, THREAD);
435 }
436
437 return superk;
438 }
439
440 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
441 Handle class_loader,
442 Handle protection_domain,
443 TRAPS) {
444 if(!has_checkPackageAccess()) return;
445
446 // Now we have to call back to java to check if the initating class has access
447 JavaValue result(T_VOID);
448 LogTarget(Debug, protectiondomain) lt;
449 if (lt.is_enabled()) {
450 ResourceMark rm;
451 // Print out trace information
452 LogStream ls(lt);
453 ls.print_cr("Checking package access");
454 ls.print("class loader: "); class_loader()->print_value_on(&ls);
455 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
456 ls.print(" loading: "); klass->print_value_on(&ls);
457 ls.cr();
458 }
459
460 // This handle and the class_loader handle passed in keeps this class from
461 // being unloaded through several GC points.
462 // The class_loader handle passed in is the initiating loader.
463 Handle mirror(THREAD, klass->java_mirror());
464
465 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
466 JavaCalls::call_special(&result,
467 class_loader,
468 system_loader,
469 vmSymbols::checkPackageAccess_name(),
470 vmSymbols::class_protectiondomain_signature(),
471 mirror,
472 protection_domain,
473 THREAD);
474
475 if (HAS_PENDING_EXCEPTION) {
476 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
477 } else {
478 log_debug(protectiondomain)("granted");
479 }
480
481 if (HAS_PENDING_EXCEPTION) return;
482
483 // If no exception has been thrown, we have validated the protection domain
484 // Insert the protection domain of the initiating class into the set.
485 {
486 ClassLoaderData* loader_data = class_loader_data(class_loader);
487 Dictionary* dictionary = loader_data->dictionary();
488
489 Symbol* kn = klass->name();
490 unsigned int d_hash = dictionary->compute_hash(kn);
491
492 MutexLocker mu(SystemDictionary_lock, THREAD);
493 int d_index = dictionary->hash_to_index(d_hash);
494 dictionary->add_protection_domain(d_index, d_hash, klass,
495 protection_domain, THREAD);
496 }
497 }
498
499 // We only get here if this thread finds that another thread
500 // has already claimed the placeholder token for the current operation,
501 // but that other thread either never owned or gave up the
502 // object lock
503 // Waits on SystemDictionary_lock to indicate placeholder table updated
504 // On return, caller must recheck placeholder table state
505 //
506 // We only get here if
507 // 1) custom classLoader, i.e. not bootstrap classloader
508 // 2) custom classLoader has broken the class loader objectLock
509 // so another thread got here in parallel
510 //
511 // lockObject must be held.
512 // Complicated dance due to lock ordering:
513 // Must first release the classloader object lock to
514 // allow initial definer to complete the class definition
515 // and to avoid deadlock
516 // Reclaim classloader lock object with same original recursion count
517 // Must release SystemDictionary_lock after notify, since
518 // class loader lock must be claimed before SystemDictionary_lock
519 // to prevent deadlocks
520 //
521 // The notify allows applications that did an untimed wait() on
522 // the classloader object lock to not hang.
523 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
524 assert_lock_strong(SystemDictionary_lock);
525
526 bool calledholdinglock
527 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
528 assert(calledholdinglock,"must hold lock for notify");
529 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
530 ObjectSynchronizer::notifyall(lockObject, THREAD);
531 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
532 SystemDictionary_lock->wait();
533 SystemDictionary_lock->unlock();
534 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
535 SystemDictionary_lock->lock();
536 }
537
538 // If the class in is in the placeholder table, class loading is in progress
539 // For cases where the application changes threads to load classes, it
540 // is critical to ClassCircularity detection that we try loading
541 // the superclass on the same thread internally, so we do parallel
542 // super class loading here.
543 // This also is critical in cases where the original thread gets stalled
544 // even in non-circularity situations.
545 // Note: must call resolve_super_or_fail even if null super -
546 // to force placeholder entry creation for this class for circularity detection
547 // Caller must check for pending exception
548 // Returns non-null Klass* if other thread has completed load
549 // and we are done,
550 // If return null Klass* and no pending exception, the caller must load the class
551 InstanceKlass* SystemDictionary::handle_parallel_super_load(
552 Symbol* name, Symbol* superclassname, Handle class_loader,
553 Handle protection_domain, Handle lockObject, TRAPS) {
554
555 ClassLoaderData* loader_data = class_loader_data(class_loader);
556 Dictionary* dictionary = loader_data->dictionary();
557 unsigned int d_hash = dictionary->compute_hash(name);
558 unsigned int p_hash = placeholders()->compute_hash(name);
559 int p_index = placeholders()->hash_to_index(p_hash);
560
561 // superk is not used, resolve_super called for circularity check only
562 // This code is reached in two situations. One if this thread
563 // is loading the same class twice (e.g. ClassCircularity, or
564 // java.lang.instrument).
565 // The second is if another thread started the resolve_super first
566 // and has not yet finished.
567 // In both cases the original caller will clean up the placeholder
568 // entry on error.
569 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
570 superclassname,
571 class_loader,
572 protection_domain,
573 true,
574 CHECK_NULL);
575
576 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
577 // Serial class loaders and bootstrap classloader do wait for superclass loads
578 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
579 MutexLocker mu(SystemDictionary_lock, THREAD);
580 // Check if classloading completed while we were loading superclass or waiting
581 return find_class(d_hash, name, dictionary);
582 }
583
584 // must loop to both handle other placeholder updates
585 // and spurious notifications
586 bool super_load_in_progress = true;
587 PlaceholderEntry* placeholder;
588 while (super_load_in_progress) {
589 MutexLocker mu(SystemDictionary_lock, THREAD);
590 // Check if classloading completed while we were loading superclass or waiting
591 InstanceKlass* check = find_class(d_hash, name, dictionary);
592 if (check != NULL) {
593 // Klass is already loaded, so just return it
594 return check;
595 } else {
596 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
597 if (placeholder && placeholder->super_load_in_progress() ){
598 // We only get here if the application has released the
599 // classloader lock when another thread was in the middle of loading a
600 // superclass/superinterface for this class, and now
601 // this thread is also trying to load this class.
602 // To minimize surprises, the first thread that started to
603 // load a class should be the one to complete the loading
604 // with the classfile it initially expected.
605 // This logic has the current thread wait once it has done
606 // all the superclass/superinterface loading it can, until
607 // the original thread completes the class loading or fails
608 // If it completes we will use the resulting InstanceKlass
609 // which we will find below in the systemDictionary.
610 // We also get here for parallel bootstrap classloader
611 if (class_loader.is_null()) {
612 SystemDictionary_lock->wait();
613 } else {
614 double_lock_wait(lockObject, THREAD);
615 }
616 } else {
617 // If not in SD and not in PH, other thread's load must have failed
618 super_load_in_progress = false;
619 }
620 }
621 }
622 return NULL;
623 }
624
625 static void post_class_load_event(EventClassLoad* event,
626 const InstanceKlass* k,
627 const ClassLoaderData* init_cld) {
628 #if INCLUDE_TRACE
629 assert(event != NULL, "invariant");
630 assert(k != NULL, "invariant");
631 if (event->should_commit()) {
632 event->set_loadedClass(k);
633 event->set_definingClassLoader(k->class_loader_data());
634 event->set_initiatingClassLoader(init_cld);
635 event->commit();
636 }
637 #endif // INCLUDE_TRACE
638 }
639
640 static void class_define_event(InstanceKlass* k,
641 const ClassLoaderData* def_cld) {
642 #if INCLUDE_TRACE
643 EventClassDefine event;
644 if (event.should_commit()) {
645 event.set_definedClass(k);
646 event.set_definingClassLoader(def_cld);
647 event.commit();
648 }
649 #endif // INCLUDE_TRACE
650 }
651
652 // Be careful when modifying this code: once you have run
653 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
654 // you need to find_and_remove it before returning.
655 // So be careful to not exit with a CHECK_ macro betweeen these calls.
656 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
657 Handle class_loader,
658 Handle protection_domain,
659 TRAPS) {
660 assert(name != NULL && !FieldType::is_array(name) &&
661 !FieldType::is_obj(name), "invalid class name");
662
663 EventClassLoad class_load_start_event;
664
665 HandleMark hm(THREAD);
666
667 // Fix for 4474172; see evaluation for more details
668 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
669 ClassLoaderData* loader_data = register_loader(class_loader);
670 Dictionary* dictionary = loader_data->dictionary();
671 unsigned int d_hash = dictionary->compute_hash(name);
672
673 // Do lookup to see if class already exist and the protection domain
674 // has the right access
675 // This call uses find which checks protection domain already matches
676 // All subsequent calls use find_class, and set has_loaded_class so that
677 // before we return a result we call out to java to check for valid protection domain
678 // to allow returning the Klass* and add it to the pd_set if it is valid
679 {
680 Klass* probe = dictionary->find(d_hash, name, protection_domain);
681 if (probe != NULL) return probe;
682 }
683
684 // Non-bootstrap class loaders will call out to class loader and
685 // define via jvm/jni_DefineClass which will acquire the
686 // class loader object lock to protect against multiple threads
687 // defining the class in parallel by accident.
688 // This lock must be acquired here so the waiter will find
689 // any successful result in the SystemDictionary and not attempt
690 // the define.
691 // ParallelCapable Classloaders and the bootstrap classloader
692 // do not acquire lock here.
693 bool DoObjectLock = true;
694 if (is_parallelCapable(class_loader)) {
695 DoObjectLock = false;
696 }
697
698 unsigned int p_hash = placeholders()->compute_hash(name);
699 int p_index = placeholders()->hash_to_index(p_hash);
700
701 // Class is not in SystemDictionary so we have to do loading.
702 // Make sure we are synchronized on the class loader before we proceed
703 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
704 check_loader_lock_contention(lockObject, THREAD);
705 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
706
707 // Check again (after locking) if class already exist in SystemDictionary
708 bool class_has_been_loaded = false;
709 bool super_load_in_progress = false;
710 bool havesupername = false;
711 InstanceKlass* k = NULL;
712 PlaceholderEntry* placeholder;
713 Symbol* superclassname = NULL;
714
715 {
716 MutexLocker mu(SystemDictionary_lock, THREAD);
717 InstanceKlass* check = find_class(d_hash, name, dictionary);
718 if (check != NULL) {
719 // Klass is already loaded, so just return it
720 class_has_been_loaded = true;
721 k = check;
722 } else {
723 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
724 if (placeholder && placeholder->super_load_in_progress()) {
725 super_load_in_progress = true;
726 if (placeholder->havesupername() == true) {
727 superclassname = placeholder->supername();
728 havesupername = true;
729 }
730 }
731 }
732 }
733
734 // If the class is in the placeholder table, class loading is in progress
735 if (super_load_in_progress && havesupername==true) {
736 k = handle_parallel_super_load(name,
737 superclassname,
738 class_loader,
739 protection_domain,
740 lockObject, THREAD);
741 if (HAS_PENDING_EXCEPTION) {
742 return NULL;
743 }
744 if (k != NULL) {
745 class_has_been_loaded = true;
746 }
747 }
748
749 bool throw_circularity_error = false;
750 if (!class_has_been_loaded) {
751 bool load_instance_added = false;
752
753 // add placeholder entry to record loading instance class
754 // Five cases:
755 // All cases need to prevent modifying bootclasssearchpath
756 // in parallel with a classload of same classname
757 // Redefineclasses uses existence of the placeholder for the duration
758 // of the class load to prevent concurrent redefinition of not completely
759 // defined classes.
760 // case 1. traditional classloaders that rely on the classloader object lock
761 // - no other need for LOAD_INSTANCE
762 // case 2. traditional classloaders that break the classloader object lock
763 // as a deadlock workaround. Detection of this case requires that
764 // this check is done while holding the classloader object lock,
765 // and that lock is still held when calling classloader's loadClass.
766 // For these classloaders, we ensure that the first requestor
767 // completes the load and other requestors wait for completion.
768 // case 3. Bootstrap classloader - don't own objectLocker
769 // This classloader supports parallelism at the classloader level,
770 // but only allows a single load of a class/classloader pair.
771 // No performance benefit and no deadlock issues.
772 // case 4. parallelCapable user level classloaders - without objectLocker
773 // Allow parallel classloading of a class/classloader pair
774
775 {
776 MutexLocker mu(SystemDictionary_lock, THREAD);
777 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
778 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
779 if (oldprobe) {
780 // only need check_seen_thread once, not on each loop
781 // 6341374 java/lang/Instrument with -Xcomp
782 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
783 throw_circularity_error = true;
784 } else {
785 // case 1: traditional: should never see load_in_progress.
786 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
787
788 // case 3: bootstrap classloader: prevent futile classloading,
789 // wait on first requestor
790 if (class_loader.is_null()) {
791 SystemDictionary_lock->wait();
792 } else {
793 // case 2: traditional with broken classloader lock. wait on first
794 // requestor.
795 double_lock_wait(lockObject, THREAD);
796 }
797 // Check if classloading completed while we were waiting
798 InstanceKlass* check = find_class(d_hash, name, dictionary);
799 if (check != NULL) {
800 // Klass is already loaded, so just return it
801 k = check;
802 class_has_been_loaded = true;
803 }
804 // check if other thread failed to load and cleaned up
805 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
806 }
807 }
808 }
809 }
810 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
811 // case 4: parallelCapable: allow competing threads to try
812 // LOAD_INSTANCE in parallel
813
814 if (!throw_circularity_error && !class_has_been_loaded) {
815 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
816 load_instance_added = true;
817 // For class loaders that do not acquire the classloader object lock,
818 // if they did not catch another thread holding LOAD_INSTANCE,
819 // need a check analogous to the acquire ObjectLocker/find_class
820 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
821 // one final check if the load has already completed
822 // class loaders holding the ObjectLock shouldn't find the class here
823 InstanceKlass* check = find_class(d_hash, name, dictionary);
824 if (check != NULL) {
825 // Klass is already loaded, so return it after checking/adding protection domain
826 k = check;
827 class_has_been_loaded = true;
828 }
829 }
830 }
831
832 // must throw error outside of owning lock
833 if (throw_circularity_error) {
834 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
835 ResourceMark rm(THREAD);
836 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
837 }
838
839 if (!class_has_been_loaded) {
840
841 // Do actual loading
842 k = load_instance_class(name, class_loader, THREAD);
843
844 // If everything was OK (no exceptions, no null return value), and
845 // class_loader is NOT the defining loader, do a little more bookkeeping.
846 if (!HAS_PENDING_EXCEPTION && k != NULL &&
847 k->class_loader() != class_loader()) {
848
849 check_constraints(d_hash, k, class_loader, false, THREAD);
850
851 // Need to check for a PENDING_EXCEPTION again; check_constraints
852 // can throw and doesn't use the CHECK macro.
853 if (!HAS_PENDING_EXCEPTION) {
854 { // Grabbing the Compile_lock prevents systemDictionary updates
855 // during compilations.
856 MutexLocker mu(Compile_lock, THREAD);
857 update_dictionary(d_hash, p_index, p_hash,
858 k, class_loader, THREAD);
859 }
860
861 if (JvmtiExport::should_post_class_load()) {
862 Thread *thread = THREAD;
863 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
864 JvmtiExport::post_class_load((JavaThread *) thread, k);
865 }
866 }
867 }
868 } // load_instance_class
869
870 if (load_instance_added == true) {
871 // clean up placeholder entries for LOAD_INSTANCE success or error
872 // This brackets the SystemDictionary updates for both defining
873 // and initiating loaders
874 MutexLocker mu(SystemDictionary_lock, THREAD);
875 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
876 SystemDictionary_lock->notify_all();
877 }
878 }
879
880 if (HAS_PENDING_EXCEPTION || k == NULL) {
881 return NULL;
882 }
883
884 post_class_load_event(&class_load_start_event, k, loader_data);
885
886 #ifdef ASSERT
887 {
888 ClassLoaderData* loader_data = k->class_loader_data();
889 MutexLocker mu(SystemDictionary_lock, THREAD);
890 Klass* kk = find_class(name, loader_data);
891 assert(kk == k, "should be present in dictionary");
892 }
893 #endif
894
895 // return if the protection domain in NULL
896 if (protection_domain() == NULL) return k;
897
898 // Check the protection domain has the right access
899 if (dictionary->is_valid_protection_domain(d_hash, name,
900 protection_domain)) {
901 return k;
902 }
903
904 // Verify protection domain. If it fails an exception is thrown
905 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
906
907 return k;
908 }
909
910
911 // This routine does not lock the system dictionary.
912 //
913 // Since readers don't hold a lock, we must make sure that system
914 // dictionary entries are only removed at a safepoint (when only one
915 // thread is running), and are added to in a safe way (all links must
916 // be updated in an MT-safe manner).
917 //
918 // Callers should be aware that an entry could be added just after
919 // _dictionary->bucket(index) is read here, so the caller will not see
920 // the new entry.
921
922 Klass* SystemDictionary::find(Symbol* class_name,
923 Handle class_loader,
924 Handle protection_domain,
925 TRAPS) {
926
927 // The result of this call should be consistent with the result
928 // of the call to resolve_instance_class_or_null().
929 // See evaluation 6790209 and 4474172 for more details.
930 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
931 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
932
933 if (loader_data == NULL) {
934 // If the ClassLoaderData has not been setup,
935 // then the class loader has no entries in the dictionary.
936 return NULL;
937 }
938
939 Dictionary* dictionary = loader_data->dictionary();
940 unsigned int d_hash = dictionary->compute_hash(class_name);
941 return dictionary->find(d_hash, class_name,
942 protection_domain);
943 }
944
945
946 // Look for a loaded instance or array klass by name. Do not do any loading.
947 // return NULL in case of error.
948 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
949 Handle class_loader,
950 Handle protection_domain,
951 TRAPS) {
952 Klass* k = NULL;
953 assert(class_name != NULL, "class name must be non NULL");
954
955 if (FieldType::is_array(class_name)) {
956 // The name refers to an array. Parse the name.
957 // dimension and object_key in FieldArrayInfo are assigned as a
958 // side-effect of this call
959 FieldArrayInfo fd;
960 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
961 if (t != T_OBJECT) {
962 k = Universe::typeArrayKlassObj(t);
963 } else {
964 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
965 }
966 if (k != NULL) {
967 k = k->array_klass_or_null(fd.dimension());
968 }
969 } else {
970 k = find(class_name, class_loader, protection_domain, THREAD);
971 }
972 return k;
973 }
974
975 // Note: this method is much like resolve_from_stream, but
976 // does not publish the classes via the SystemDictionary.
977 // Handles unsafe_DefineAnonymousClass and redefineclasses
978 // RedefinedClasses do not add to the class hierarchy
979 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
980 Handle class_loader,
981 Handle protection_domain,
982 ClassFileStream* st,
983 const InstanceKlass* host_klass,
984 GrowableArray<Handle>* cp_patches,
985 TRAPS) {
986
987 EventClassLoad class_load_start_event;
988
989 ClassLoaderData* loader_data;
990 if (host_klass != NULL) {
991 // Create a new CLD for anonymous class, that uses the same class loader
992 // as the host_klass
993 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
994 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
995 } else {
996 loader_data = ClassLoaderData::class_loader_data(class_loader());
997 }
998
999 assert(st != NULL, "invariant");
1000 assert(st->need_verify(), "invariant");
1001
1002 // Parse stream and create a klass.
1003 // Note that we do this even though this klass might
1004 // already be present in the SystemDictionary, otherwise we would not
1005 // throw potential ClassFormatErrors.
1006
1007 InstanceKlass* k = KlassFactory::create_from_stream(st,
1008 class_name,
1009 loader_data,
1010 protection_domain,
1011 host_klass,
1012 cp_patches,
1013 CHECK_NULL);
1014
1015 if (host_klass != NULL && k != NULL) {
1016 // If it's anonymous, initialize it now, since nobody else will.
1017
1018 {
1019 MutexLocker mu_r(Compile_lock, THREAD);
1020
1021 // Add to class hierarchy, initialize vtables, and do possible
1022 // deoptimizations.
1023 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1024
1025 // But, do not add to dictionary.
1026
1027 // compiled code dependencies need to be validated anyway
1028 notice_modification();
1029 }
1030
1031 // Rewrite and patch constant pool here.
1032 k->link_class(CHECK_NULL);
1033 if (cp_patches != NULL) {
1034 k->constants()->patch_resolved_references(cp_patches);
1035 }
1036 k->eager_initialize(CHECK_NULL);
1037
1038 // notify jvmti
1039 if (JvmtiExport::should_post_class_load()) {
1040 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1041 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1042 }
1043
1044 post_class_load_event(&class_load_start_event, k, loader_data);
1045 }
1046 assert(host_klass != NULL || NULL == cp_patches,
1047 "cp_patches only found with host_klass");
1048
1049 return k;
1050 }
1051
1052 // Add a klass to the system from a stream (called by jni_DefineClass and
1053 // JVM_DefineClass).
1054 // Note: class_name can be NULL. In that case we do not know the name of
1055 // the class until we have parsed the stream.
1056
1057 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1058 Handle class_loader,
1059 Handle protection_domain,
1060 ClassFileStream* st,
1061 TRAPS) {
1062
1063 HandleMark hm(THREAD);
1064
1065 // Classloaders that support parallelism, e.g. bootstrap classloader,
1066 // do not acquire lock here
1067 bool DoObjectLock = true;
1068 if (is_parallelCapable(class_loader)) {
1069 DoObjectLock = false;
1070 }
1071
1072 ClassLoaderData* loader_data = register_loader(class_loader);
1073
1074 // Make sure we are synchronized on the class loader before we proceed
1075 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1076 check_loader_lock_contention(lockObject, THREAD);
1077 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1078
1079 assert(st != NULL, "invariant");
1080
1081 // Parse the stream and create a klass.
1082 // Note that we do this even though this klass might
1083 // already be present in the SystemDictionary, otherwise we would not
1084 // throw potential ClassFormatErrors.
1085 InstanceKlass* k = NULL;
1086
1087 #if INCLUDE_CDS
1088 if (!DumpSharedSpaces) {
1089 k = SystemDictionaryShared::lookup_from_stream(class_name,
1090 class_loader,
1091 protection_domain,
1092 st,
1093 CHECK_NULL);
1094 }
1095 #endif
1096
1097 if (k == NULL) {
1098 if (st->buffer() == NULL) {
1099 return NULL;
1100 }
1101 k = KlassFactory::create_from_stream(st,
1102 class_name,
1103 loader_data,
1104 protection_domain,
1105 NULL, // host_klass
1106 NULL, // cp_patches
1107 CHECK_NULL);
1108 }
1109
1110 assert(k != NULL, "no klass created");
1111 Symbol* h_name = k->name();
1112 assert(class_name == NULL || class_name == h_name, "name mismatch");
1113
1114 // Add class just loaded
1115 // If a class loader supports parallel classloading handle parallel define requests
1116 // find_or_define_instance_class may return a different InstanceKlass
1117 if (is_parallelCapable(class_loader)) {
1118 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1119 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1120 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1121 assert(defined_k != NULL, "Should have a klass if there's no exception");
1122 loader_data->add_to_deallocate_list(k);
1123 k = defined_k;
1124 }
1125 } else {
1126 define_instance_class(k, THREAD);
1127 }
1128
1129 // If defining the class throws an exception register 'k' for cleanup.
1130 if (HAS_PENDING_EXCEPTION) {
1131 assert(k != NULL, "Must have an instance klass here!");
1132 loader_data->add_to_deallocate_list(k);
1133 return NULL;
1134 }
1135
1136 // Make sure we have an entry in the SystemDictionary on success
1137 debug_only( {
1138 MutexLocker mu(SystemDictionary_lock, THREAD);
1139
1140 Klass* check = find_class(h_name, k->class_loader_data());
1141 assert(check == k, "should be present in the dictionary");
1142 } );
1143
1144 return k;
1145 }
1146
1147 #if INCLUDE_CDS
1148 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1149 int number_of_entries) {
1150 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1151 "bad shared dictionary size.");
1152 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1153 _shared_dictionary_size, t, number_of_entries);
1154 }
1155
1156
1157 // If there is a shared dictionary, then find the entry for the
1158 // given shared system class, if any.
1159
1160 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1161 if (shared_dictionary() != NULL) {
1162 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1163 int d_index = shared_dictionary()->hash_to_index(d_hash);
1164
1165 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1166 } else {
1167 return NULL;
1168 }
1169 }
1170
1171
1172 // Load a class from the shared spaces (found through the shared system
1173 // dictionary). Force the superclass and all interfaces to be loaded.
1174 // Update the class definition to include sibling classes and no
1175 // subclasses (yet). [Classes in the shared space are not part of the
1176 // object hierarchy until loaded.]
1177
1178 InstanceKlass* SystemDictionary::load_shared_class(
1179 Symbol* class_name, Handle class_loader, TRAPS) {
1180 InstanceKlass* ik = find_shared_class(class_name);
1181 // Make sure we only return the boot class for the NULL classloader.
1182 if (ik != NULL &&
1183 ik->is_shared_boot_class() && class_loader.is_null()) {
1184 Handle protection_domain;
1185 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1186 }
1187 return NULL;
1188 }
1189
1190 // Check if a shared class can be loaded by the specific classloader:
1191 //
1192 // NULL classloader:
1193 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1194 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1195 // be defined in an unnamed module.
1196 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1197 InstanceKlass* ik,
1198 Handle class_loader, TRAPS) {
1199 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1200 "Cannot use sharing if java.base is patched");
1201 ResourceMark rm;
1202 int path_index = ik->shared_classpath_index();
1203 ClassLoaderData* loader_data = class_loader_data(class_loader);
1204 if (path_index < 0) {
1205 // path_index < 0 indicates that the class is intended for a custom loader
1206 // and should not be loaded by boot/platform/app loaders
1207 if (loader_data->is_builtin_class_loader_data()) {
1208 return false;
1209 } else {
1210 return true;
1211 }
1212 }
1213 SharedClassPathEntry* ent =
1214 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1215 if (!Universe::is_module_initialized()) {
1216 assert(ent != NULL && ent->is_modules_image(),
1217 "Loading non-bootstrap classes before the module system is initialized");
1218 assert(class_loader.is_null(), "sanity");
1219 return true;
1220 }
1221 // Get the pkg_entry from the classloader
1222 TempNewSymbol pkg_name = NULL;
1223 PackageEntry* pkg_entry = NULL;
1224 ModuleEntry* mod_entry = NULL;
1225 const char* pkg_string = NULL;
1226 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1227 if (pkg_name != NULL) {
1228 pkg_string = pkg_name->as_C_string();
1229 if (loader_data != NULL) {
1230 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1231 }
1232 if (pkg_entry != NULL) {
1233 mod_entry = pkg_entry->module();
1234 }
1235 }
1236
1237 // If the archived class is from a module that has been patched at runtime,
1238 // the class cannot be loaded from the archive.
1239 if (mod_entry != NULL && mod_entry->is_patched()) {
1240 return false;
1241 }
1242
1243 if (class_loader.is_null()) {
1244 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1245 // The NULL classloader can load archived class originated from the
1246 // "modules" jimage and the -Xbootclasspath/a. For class from the
1247 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1248 // by the NULL classloader.
1249 if (mod_entry != NULL) {
1250 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1251 // ModuleEntry's location agrees with the archived class' origination.
1252 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1253 return true; // Module class from the "module" jimage
1254 }
1255 }
1256
1257 // If the archived class is not from the "module" jimage, the class can be
1258 // loaded by the NULL classloader if
1259 //
1260 // 1. the class is from the unamed package
1261 // 2. or, the class is not from a module defined in the NULL classloader
1262 // 3. or, the class is from an unamed module
1263 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1264 // the class is from the -Xbootclasspath/a
1265 if (pkg_string == NULL ||
1266 pkg_entry == NULL ||
1267 pkg_entry->in_unnamed_module()) {
1268 assert(mod_entry == NULL ||
1269 mod_entry == loader_data->unnamed_module(),
1270 "the unnamed module is not defined in the classloader");
1271 return true;
1272 }
1273 }
1274 return false;
1275 } else {
1276 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1277 ik, class_loader, pkg_string, pkg_name,
1278 pkg_entry, mod_entry, CHECK_(false));
1279 return res;
1280 }
1281 }
1282
1283 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1284 Handle class_loader,
1285 Handle protection_domain, TRAPS) {
1286
1287 if (ik != NULL) {
1288 Symbol* class_name = ik->name();
1289
1290 bool visible = is_shared_class_visible(
1291 class_name, ik, class_loader, CHECK_NULL);
1292 if (!visible) {
1293 return NULL;
1294 }
1295
1296 // Resolve the superclass and interfaces. They must be the same
1297 // as in dump time, because the layout of <ik> depends on
1298 // the specific layout of ik->super() and ik->local_interfaces().
1299 //
1300 // If unexpected superclass or interfaces are found, we cannot
1301 // load <ik> from the shared archive.
1302
1303 if (ik->super() != NULL) {
1304 Symbol* cn = ik->super()->name();
1305 Klass *s = resolve_super_or_fail(class_name, cn,
1306 class_loader, protection_domain, true, CHECK_NULL);
1307 if (s != ik->super()) {
1308 // The dynamically resolved super class is not the same as the one we used during dump time,
1309 // so we cannot use ik.
1310 return NULL;
1311 } else {
1312 assert(s->is_shared(), "must be");
1313 }
1314 }
1315
1316 Array<Klass*>* interfaces = ik->local_interfaces();
1317 int num_interfaces = interfaces->length();
1318 for (int index = 0; index < num_interfaces; index++) {
1319 Klass* k = interfaces->at(index);
1320 Symbol* name = k->name();
1321 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1322 if (k != i) {
1323 // The dynamically resolved interface class is not the same as the one we used during dump time,
1324 // so we cannot use ik.
1325 return NULL;
1326 } else {
1327 assert(i->is_shared(), "must be");
1328 }
1329 }
1330
1331 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1332 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1333 if (new_ik != NULL) {
1334 // The class is changed by CFLH. Return the new class. The shared class is
1335 // not used.
1336 return new_ik;
1337 }
1338
1339 // Adjust methods to recover missing data. They need addresses for
1340 // interpreter entry points and their default native method address
1341 // must be reset.
1342
1343 // Updating methods must be done under a lock so multiple
1344 // threads don't update these in parallel
1345 //
1346 // Shared classes are all currently loaded by either the bootstrap or
1347 // internal parallel class loaders, so this will never cause a deadlock
1348 // on a custom class loader lock.
1349
1350 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1351 {
1352 HandleMark hm(THREAD);
1353 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1354 check_loader_lock_contention(lockObject, THREAD);
1355 ObjectLocker ol(lockObject, THREAD, true);
1356 // prohibited package check assumes all classes loaded from archive call
1357 // restore_unshareable_info which calls ik->set_package()
1358 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1359 }
1360
1361 ik->print_class_load_logging(loader_data, NULL, NULL);
1362
1363 // For boot loader, ensure that GetSystemPackage knows that a class in this
1364 // package was loaded.
1365 if (class_loader.is_null()) {
1366 int path_index = ik->shared_classpath_index();
1367 ResourceMark rm;
1368 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1369 }
1370
1371 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1372 // Only dump the classes that can be stored into CDS archive
1373 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1374 ResourceMark rm(THREAD);
1375 classlist_file->print_cr("%s", ik->name()->as_C_string());
1376 classlist_file->flush();
1377 }
1378 }
1379
1380 // notify a class loaded from shared object
1381 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1382 }
1383
1384 ik->set_has_passed_fingerprint_check(false);
1385 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1386 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1387 uint64_t cds_fp = ik->get_stored_fingerprint();
1388 if (aot_fp != 0 && aot_fp == cds_fp) {
1389 // This class matches with a class saved in an AOT library
1390 ik->set_has_passed_fingerprint_check(true);
1391 } else {
1392 ResourceMark rm;
1393 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1394 }
1395 }
1396 return ik;
1397 }
1398
1399 void SystemDictionary::clear_invoke_method_table() {
1400 SymbolPropertyEntry* spe = NULL;
1401 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1402 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1403 while (p != NULL) {
1404 spe = p;
1405 p = p->next();
1406 _invoke_method_table->free_entry(spe);
1407 }
1408 }
1409 }
1410 #endif // INCLUDE_CDS
1411
1412 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1413
1414 if (class_loader.is_null()) {
1415 ResourceMark rm;
1416 PackageEntry* pkg_entry = NULL;
1417 bool search_only_bootloader_append = false;
1418 ClassLoaderData *loader_data = class_loader_data(class_loader);
1419
1420 // Find the package in the boot loader's package entry table.
1421 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1422 if (pkg_name != NULL) {
1423 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1424 }
1425
1426 // Prior to attempting to load the class, enforce the boot loader's
1427 // visibility boundaries.
1428 if (!Universe::is_module_initialized()) {
1429 // During bootstrapping, prior to module initialization, any
1430 // class attempting to be loaded must be checked against the
1431 // java.base packages in the boot loader's PackageEntryTable.
1432 // No class outside of java.base is allowed to be loaded during
1433 // this bootstrapping window.
1434 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1435 // Class is either in the unnamed package or in
1436 // a named package within the unnamed module. Either
1437 // case is outside of java.base, do not attempt to
1438 // load the class post java.base definition. If
1439 // java.base has not been defined, let the class load
1440 // and its package will be checked later by
1441 // ModuleEntryTable::verify_javabase_packages.
1442 if (ModuleEntryTable::javabase_defined()) {
1443 return NULL;
1444 }
1445 } else {
1446 // Check that the class' package is defined within java.base.
1447 ModuleEntry* mod_entry = pkg_entry->module();
1448 Symbol* mod_entry_name = mod_entry->name();
1449 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1450 return NULL;
1451 }
1452 }
1453 } else {
1454 // After the module system has been initialized, check if the class'
1455 // package is in a module defined to the boot loader.
1456 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1457 // Class is either in the unnamed package, in a named package
1458 // within a module not defined to the boot loader or in a
1459 // a named package within the unnamed module. In all cases,
1460 // limit visibility to search for the class only in the boot
1461 // loader's append path.
1462 search_only_bootloader_append = true;
1463 }
1464 }
1465
1466 // Prior to bootstrapping's module initialization, never load a class outside
1467 // of the boot loader's module path
1468 assert(Universe::is_module_initialized() ||
1469 !search_only_bootloader_append,
1470 "Attempt to load a class outside of boot loader's module path");
1471
1472 // Search the shared system dictionary for classes preloaded into the
1473 // shared spaces.
1474 InstanceKlass* k = NULL;
1475 {
1476 #if INCLUDE_CDS
1477 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1478 k = load_shared_class(class_name, class_loader, THREAD);
1479 #endif
1480 }
1481
1482 if (k == NULL) {
1483 // Use VM class loader
1484 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1485 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1486 }
1487
1488 // find_or_define_instance_class may return a different InstanceKlass
1489 if (k != NULL) {
1490 InstanceKlass* defined_k =
1491 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1492 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1493 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1494 assert(defined_k != NULL, "Should have a klass if there's no exception");
1495 loader_data->add_to_deallocate_list(k);
1496 k = defined_k;
1497 } else if (HAS_PENDING_EXCEPTION) {
1498 loader_data->add_to_deallocate_list(k);
1499 return NULL;
1500 }
1501 }
1502 return k;
1503 } else {
1504 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1505 ResourceMark rm(THREAD);
1506
1507 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1508 JavaThread* jt = (JavaThread*) THREAD;
1509
1510 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1511 ClassLoader::perf_app_classload_selftime(),
1512 ClassLoader::perf_app_classload_count(),
1513 jt->get_thread_stat()->perf_recursion_counts_addr(),
1514 jt->get_thread_stat()->perf_timers_addr(),
1515 PerfClassTraceTime::CLASS_LOAD);
1516
1517 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1518 // Translate to external class name format, i.e., convert '/' chars to '.'
1519 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1520
1521 JavaValue result(T_OBJECT);
1522
1523 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1524
1525 // Call public unsynchronized loadClass(String) directly for all class loaders.
1526 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1527 // acquire a class-name based lock rather than the class loader object lock.
1528 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1529 JavaCalls::call_virtual(&result,
1530 class_loader,
1531 spec_klass,
1532 vmSymbols::loadClass_name(),
1533 vmSymbols::string_class_signature(),
1534 string,
1535 CHECK_NULL);
1536
1537 assert(result.get_type() == T_OBJECT, "just checking");
1538 oop obj = (oop) result.get_jobject();
1539
1540 // Primitive classes return null since forName() can not be
1541 // used to obtain any of the Class objects representing primitives or void
1542 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1543 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1544 // For user defined Java class loaders, check that the name returned is
1545 // the same as that requested. This check is done for the bootstrap
1546 // loader when parsing the class file.
1547 if (class_name == k->name()) {
1548 return k;
1549 }
1550 }
1551 // Class is not found or has the wrong name, return NULL
1552 return NULL;
1553 }
1554 }
1555
1556 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1557
1558 HandleMark hm(THREAD);
1559 ClassLoaderData* loader_data = k->class_loader_data();
1560 Handle class_loader_h(THREAD, loader_data->class_loader());
1561
1562 // for bootstrap and other parallel classloaders don't acquire lock,
1563 // use placeholder token
1564 // If a parallelCapable class loader calls define_instance_class instead of
1565 // find_or_define_instance_class to get here, we have a timing
1566 // hole with systemDictionary updates and check_constraints
1567 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1568 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1569 compute_loader_lock_object(class_loader_h, THREAD)),
1570 "define called without lock");
1571 }
1572
1573 // Check class-loading constraints. Throw exception if violation is detected.
1574 // Grabs and releases SystemDictionary_lock
1575 // The check_constraints/find_class call and update_dictionary sequence
1576 // must be "atomic" for a specific class/classloader pair so we never
1577 // define two different instanceKlasses for that class/classloader pair.
1578 // Existing classloaders will call define_instance_class with the
1579 // classloader lock held
1580 // Parallel classloaders will call find_or_define_instance_class
1581 // which will require a token to perform the define class
1582 Symbol* name_h = k->name();
1583 Dictionary* dictionary = loader_data->dictionary();
1584 unsigned int d_hash = dictionary->compute_hash(name_h);
1585 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1586
1587 // Register class just loaded with class loader (placed in Vector)
1588 // Note we do this before updating the dictionary, as this can
1589 // fail with an OutOfMemoryError (if it does, we will *not* put this
1590 // class in the dictionary and will not update the class hierarchy).
1591 // JVMTI FollowReferences needs to find the classes this way.
1592 if (k->class_loader() != NULL) {
1593 methodHandle m(THREAD, Universe::loader_addClass_method());
1594 JavaValue result(T_VOID);
1595 JavaCallArguments args(class_loader_h);
1596 args.push_oop(Handle(THREAD, k->java_mirror()));
1597 JavaCalls::call(&result, m, &args, CHECK);
1598 }
1599
1600 // Add the new class. We need recompile lock during update of CHA.
1601 {
1602 unsigned int p_hash = placeholders()->compute_hash(name_h);
1603 int p_index = placeholders()->hash_to_index(p_hash);
1604
1605 MutexLocker mu_r(Compile_lock, THREAD);
1606
1607 // Add to class hierarchy, initialize vtables, and do possible
1608 // deoptimizations.
1609 add_to_hierarchy(k, CHECK); // No exception, but can block
1610
1611 // Add to systemDictionary - so other classes can see it.
1612 // Grabs and releases SystemDictionary_lock
1613 update_dictionary(d_hash, p_index, p_hash,
1614 k, class_loader_h, THREAD);
1615 }
1616 k->eager_initialize(THREAD);
1617
1618 // notify jvmti
1619 if (JvmtiExport::should_post_class_load()) {
1620 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1621 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1622
1623 }
1624 class_define_event(k, loader_data);
1625 }
1626
1627 // Support parallel classloading
1628 // All parallel class loaders, including bootstrap classloader
1629 // lock a placeholder entry for this class/class_loader pair
1630 // to allow parallel defines of different classes for this class loader
1631 // With AllowParallelDefine flag==true, in case they do not synchronize around
1632 // FindLoadedClass/DefineClass, calls, we check for parallel
1633 // loading for them, wait if a defineClass is in progress
1634 // and return the initial requestor's results
1635 // This flag does not apply to the bootstrap classloader.
1636 // With AllowParallelDefine flag==false, call through to define_instance_class
1637 // which will throw LinkageError: duplicate class definition.
1638 // False is the requested default.
1639 // For better performance, the class loaders should synchronize
1640 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1641 // potentially waste time reading and parsing the bytestream.
1642 // Note: VM callers should ensure consistency of k/class_name,class_loader
1643 // Be careful when modifying this code: once you have run
1644 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1645 // you need to find_and_remove it before returning.
1646 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1647 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1648 InstanceKlass* k, TRAPS) {
1649
1650 Symbol* name_h = k->name(); // passed in class_name may be null
1651 ClassLoaderData* loader_data = class_loader_data(class_loader);
1652 Dictionary* dictionary = loader_data->dictionary();
1653
1654 unsigned int d_hash = dictionary->compute_hash(name_h);
1655
1656 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1657 unsigned int p_hash = placeholders()->compute_hash(name_h);
1658 int p_index = placeholders()->hash_to_index(p_hash);
1659 PlaceholderEntry* probe;
1660
1661 {
1662 MutexLocker mu(SystemDictionary_lock, THREAD);
1663 // First check if class already defined
1664 if (is_parallelDefine(class_loader)) {
1665 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1666 if (check != NULL) {
1667 return check;
1668 }
1669 }
1670
1671 // Acquire define token for this class/classloader
1672 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1673 // Wait if another thread defining in parallel
1674 // All threads wait - even those that will throw duplicate class: otherwise
1675 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1676 // if other thread has not finished updating dictionary
1677 while (probe->definer() != NULL) {
1678 SystemDictionary_lock->wait();
1679 }
1680 // Only special cases allow parallel defines and can use other thread's results
1681 // Other cases fall through, and may run into duplicate defines
1682 // caught by finding an entry in the SystemDictionary
1683 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1684 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1685 SystemDictionary_lock->notify_all();
1686 #ifdef ASSERT
1687 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1688 assert(check != NULL, "definer missed recording success");
1689 #endif
1690 return probe->instance_klass();
1691 } else {
1692 // This thread will define the class (even if earlier thread tried and had an error)
1693 probe->set_definer(THREAD);
1694 }
1695 }
1696
1697 define_instance_class(k, THREAD);
1698
1699 Handle linkage_exception = Handle(); // null handle
1700
1701 // definer must notify any waiting threads
1702 {
1703 MutexLocker mu(SystemDictionary_lock, THREAD);
1704 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1705 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1706 if (probe != NULL) {
1707 if (HAS_PENDING_EXCEPTION) {
1708 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1709 CLEAR_PENDING_EXCEPTION;
1710 } else {
1711 probe->set_instance_klass(k);
1712 }
1713 probe->set_definer(NULL);
1714 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1715 SystemDictionary_lock->notify_all();
1716 }
1717 }
1718
1719 // Can't throw exception while holding lock due to rank ordering
1720 if (linkage_exception() != NULL) {
1721 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1722 }
1723
1724 return k;
1725 }
1726
1727 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1728 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1729 if (class_loader.is_null()) {
1730 return Handle(THREAD, _system_loader_lock_obj);
1731 } else {
1732 return class_loader;
1733 }
1734 }
1735
1736 // This method is added to check how often we have to wait to grab loader
1737 // lock. The results are being recorded in the performance counters defined in
1738 // ClassLoader::_sync_systemLoaderLockContentionRate and
1739 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1740 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1741 if (!UsePerfData) {
1742 return;
1743 }
1744
1745 assert(!loader_lock.is_null(), "NULL lock object");
1746
1747 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1748 == ObjectSynchronizer::owner_other) {
1749 // contention will likely happen, so increment the corresponding
1750 // contention counter.
1751 if (loader_lock() == _system_loader_lock_obj) {
1752 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1753 } else {
1754 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1755 }
1756 }
1757 }
1758
1759 // ----------------------------------------------------------------------------
1760 // Lookup
1761
1762 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1763 Symbol* class_name,
1764 Dictionary* dictionary) {
1765 assert_locked_or_safepoint(SystemDictionary_lock);
1766 int index = dictionary->hash_to_index(hash);
1767 return dictionary->find_class(index, hash, class_name);
1768 }
1769
1770
1771 // Basic find on classes in the midst of being loaded
1772 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1773 ClassLoaderData* loader_data) {
1774 assert_locked_or_safepoint(SystemDictionary_lock);
1775 unsigned int p_hash = placeholders()->compute_hash(class_name);
1776 int p_index = placeholders()->hash_to_index(p_hash);
1777 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1778 }
1779
1780
1781 // Used for assertions and verification only
1782 // Precalculating the hash and index is an optimization because there are many lookups
1783 // before adding the class.
1784 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1785 assert_locked_or_safepoint(SystemDictionary_lock);
1786 #ifndef ASSERT
1787 guarantee(VerifyBeforeGC ||
1788 VerifyDuringGC ||
1789 VerifyBeforeExit ||
1790 VerifyDuringStartup ||
1791 VerifyAfterGC, "too expensive");
1792 #endif
1793
1794 Dictionary* dictionary = loader_data->dictionary();
1795 unsigned int d_hash = dictionary->compute_hash(class_name);
1796 return find_class(d_hash, class_name, dictionary);
1797 }
1798
1799
1800 // ----------------------------------------------------------------------------
1801 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1802 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1803 // before a new class is used.
1804
1805 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1806 assert(k != NULL, "just checking");
1807 assert_locked_or_safepoint(Compile_lock);
1808
1809 // Link into hierachy. Make sure the vtables are initialized before linking into
1810 k->append_to_sibling_list(); // add to superklass/sibling list
1811 k->process_interfaces(THREAD); // handle all "implements" declarations
1812 k->set_init_state(InstanceKlass::loaded);
1813 // Now flush all code that depended on old class hierarchy.
1814 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1815 // Also, first reinitialize vtable because it may have gotten out of synch
1816 // while the new class wasn't connected to the class hierarchy.
1817 CodeCache::flush_dependents_on(k);
1818 }
1819
1820 // ----------------------------------------------------------------------------
1821 // GC support
1822
1823 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1824 roots_oops_do(blk, NULL);
1825 }
1826
1827
1828 #ifdef ASSERT
1829 class VerifySDReachableAndLiveClosure : public OopClosure {
1830 private:
1831 BoolObjectClosure* _is_alive;
1832
1833 template <class T> void do_oop_work(T* p) {
1834 oop obj = RawAccess<>::oop_load(p);
1835 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1836 }
1837
1838 public:
1839 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1840
1841 virtual void do_oop(oop* p) { do_oop_work(p); }
1842 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1843 };
1844 #endif
1845
1846 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1847 // Note: anonymous classes are not in the SD.
1848 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1849 GCTimer* gc_timer,
1850 bool do_cleaning) {
1851
1852
1853 bool unloading_occurred;
1854 {
1855 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1856
1857 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1858 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1859 do_cleaning);
1860 }
1861
1862 if (unloading_occurred) {
1863 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1864 constraints()->purge_loader_constraints();
1865 resolution_errors()->purge_resolution_errors();
1866 }
1867
1868 {
1869 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1870 // Oops referenced by the protection domain cache table may get unreachable independently
1871 // of the class loader (eg. cached protection domain oops). So we need to
1872 // explicitly unlink them here.
1873 _pd_cache_table->unlink(is_alive);
1874
1875 #ifdef ASSERT
1876 VerifySDReachableAndLiveClosure cl(is_alive);
1877 _pd_cache_table->oops_do(&cl);
1878 #endif
1879 }
1880
1881 if (do_cleaning) {
1882 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1883 ResolvedMethodTable::unlink(is_alive);
1884 }
1885
1886 return unloading_occurred;
1887 }
1888
1889 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1890 strong->do_oop(&_java_system_loader);
1891 strong->do_oop(&_java_platform_loader);
1892 strong->do_oop(&_system_loader_lock_obj);
1893 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1894
1895 // Do strong roots marking if the closures are the same.
1896 if (strong == weak || !ClassUnloading) {
1897 // Only the protection domain oops contain references into the heap. Iterate
1898 // over all of them.
1899 _pd_cache_table->oops_do(strong);
1900 } else {
1901 if (weak != NULL) {
1902 _pd_cache_table->oops_do(weak);
1903 }
1904 }
1905
1906 // Visit extra methods
1907 invoke_method_table()->oops_do(strong);
1908
1909 if (weak != NULL) {
1910 ResolvedMethodTable::oops_do(weak);
1911 }
1912 }
1913
1914 void SystemDictionary::oops_do(OopClosure* f) {
1915 f->do_oop(&_java_system_loader);
1916 f->do_oop(&_java_platform_loader);
1917 f->do_oop(&_system_loader_lock_obj);
1918 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1919
1920 // Only the protection domain oops contain references into the heap. Iterate
1921 // over all of them.
1922 _pd_cache_table->oops_do(f);
1923
1924 // Visit extra methods
1925 invoke_method_table()->oops_do(f);
1926
1927 ResolvedMethodTable::oops_do(f);
1928 }
1929
1930 // CDS: scan and relocate all classes in the system dictionary.
1931 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1932 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1933 }
1934
1935 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1936 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1937 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1938 it->push(well_known_klass_addr((WKID)id));
1939 }
1940 }
1941
1942 void SystemDictionary::methods_do(void f(Method*)) {
1943 // Walk methods in loaded classes
1944 ClassLoaderDataGraph::methods_do(f);
1945 // Walk method handle intrinsics
1946 invoke_method_table()->methods_do(f);
1947 }
1948
1949 class RemoveClassesClosure : public CLDClosure {
1950 public:
1951 void do_cld(ClassLoaderData* cld) {
1952 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1953 cld->dictionary()->remove_classes_in_error_state();
1954 }
1955 }
1956 };
1957
1958 void SystemDictionary::remove_classes_in_error_state() {
1959 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1960 RemoveClassesClosure rcc;
1961 ClassLoaderDataGraph::cld_do(&rcc);
1962 }
1963
1964 // ----------------------------------------------------------------------------
1965 // Lazily load klasses
1966
1967 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1968 // if multiple threads calling this function, only one thread will load
1969 // the class. The other threads will find the loaded version once the
1970 // class is loaded.
1971 Klass* aos = _abstract_ownable_synchronizer_klass;
1972 if (aos == NULL) {
1973 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1974 // Force a fence to prevent any read before the write completes
1975 OrderAccess::fence();
1976 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1977 }
1978 }
1979
1980 // ----------------------------------------------------------------------------
1981 // Initialization
1982
1983 void SystemDictionary::initialize(TRAPS) {
1984 // Allocate arrays
1985 _placeholders = new PlaceholderTable(_placeholder_table_size);
1986 _number_of_modifications = 0;
1987 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1988 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1989 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1990 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1991
1992 // Allocate private object used as system class loader lock
1993 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1994 // Initialize basic classes
1995 initialize_preloaded_classes(CHECK);
1996 }
1997
1998 // Compact table of directions on the initialization of klasses:
1999 static const short wk_init_info[] = {
2000 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2001 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2002 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2003 | (int)SystemDictionary::option ),
2004 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2005 #undef WK_KLASS_INIT_INFO
2006 0
2007 };
2008
2009 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2010 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2011 int info = wk_init_info[id - FIRST_WKID];
2012 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2013 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2014 InstanceKlass** klassp = &_well_known_klasses[id];
2015
2016 bool must_load;
2017 #if INCLUDE_JVMCI
2018 if (EnableJVMCI) {
2019 // If JVMCI is enabled we require its classes to be found.
2020 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2021 } else
2022 #endif
2023 {
2024 must_load = (init_opt < SystemDictionary::Opt);
2025 }
2026
2027 if ((*klassp) == NULL) {
2028 Klass* k;
2029 if (must_load) {
2030 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2031 } else {
2032 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2033 }
2034 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2035 }
2036 return ((*klassp) != NULL);
2037 }
2038
2039 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2040 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2041 for (int id = (int)start_id; id < (int)limit_id; id++) {
2042 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2043 int info = wk_init_info[id - FIRST_WKID];
2044 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2045 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2046
2047 initialize_wk_klass((WKID)id, opt, CHECK);
2048 }
2049
2050 // move the starting value forward to the limit:
2051 start_id = limit_id;
2052 }
2053
2054 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2055 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2056
2057 // Create the ModuleEntry for java.base. This call needs to be done here,
2058 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2059 ClassLoader::classLoader_init2(CHECK);
2060
2061 // Preload commonly used klasses
2062 WKID scan = FIRST_WKID;
2063 // first do Object, then String, Class
2064 #if INCLUDE_CDS
2065 if (UseSharedSpaces) {
2066 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2067 // Initialize the constant pool for the Object_class
2068 Object_klass()->constants()->restore_unshareable_info(CHECK);
2069 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2070 } else
2071 #endif
2072 {
2073 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2074 }
2075
2076 // Calculate offsets for String and Class classes since they are loaded and
2077 // can be used after this point.
2078 java_lang_String::compute_offsets();
2079 java_lang_Class::compute_offsets();
2080
2081 // Fixup mirrors for classes loaded before java.lang.Class.
2082 // These calls iterate over the objects currently in the perm gen
2083 // so calling them at this point is matters (not before when there
2084 // are fewer objects and not later after there are more objects
2085 // in the perm gen.
2086 Universe::initialize_basic_type_mirrors(CHECK);
2087 Universe::fixup_mirrors(CHECK);
2088
2089 // do a bunch more:
2090 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2091
2092 // Preload ref klasses and set reference types
2093 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2094 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2095
2096 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2097 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2098 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2099 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2100 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2101
2102 // JSR 292 classes
2103 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2104 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2105 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2106 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2107 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2108
2109 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2110 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2111 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2112 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2113 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2114 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2115 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2116 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2117 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2118 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2119
2120 { // Compute whether we should use checkPackageAccess or NOT
2121 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2122 _has_checkPackageAccess = (method != NULL);
2123 }
2124 }
2125
2126 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2127 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2128 BasicType SystemDictionary::box_klass_type(Klass* k) {
2129 assert(k != NULL, "");
2130 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2131 if (_box_klasses[i] == k)
2132 return (BasicType)i;
2133 }
2134 return T_OBJECT;
2135 }
2136
2137 // Constraints on class loaders. The details of the algorithm can be
2138 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2139 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2140 // that the dictionary needs to maintain a set of contraints that
2141 // must be satisfied by all classes in the dictionary.
2142 // if defining is true, then LinkageError if already in dictionary
2143 // if initiating loader, then ok if InstanceKlass matches existing entry
2144
2145 void SystemDictionary::check_constraints(unsigned int d_hash,
2146 InstanceKlass* k,
2147 Handle class_loader, bool defining,
2148 TRAPS) {
2149 const char *linkage_error1 = NULL;
2150 const char *linkage_error2 = NULL;
2151 {
2152 Symbol* name = k->name();
2153 ClassLoaderData *loader_data = class_loader_data(class_loader);
2154
2155 MutexLocker mu(SystemDictionary_lock, THREAD);
2156
2157 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2158 if (check != NULL) {
2159 // if different InstanceKlass - duplicate class definition,
2160 // else - ok, class loaded by a different thread in parallel,
2161 // we should only have found it if it was done loading and ok to use
2162 // dictionary only holds instance classes, placeholders
2163 // also holds array classes
2164
2165 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2166 if ((defining == true) || (k != check)) {
2167 linkage_error1 = "loader (instance of ";
2168 linkage_error2 = "): attempted duplicate class definition for name: \"";
2169 } else {
2170 return;
2171 }
2172 }
2173
2174 #ifdef ASSERT
2175 Symbol* ph_check = find_placeholder(name, loader_data);
2176 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2177 #endif
2178
2179 if (linkage_error1 == NULL) {
2180 if (constraints()->check_or_update(k, class_loader, name) == false) {
2181 linkage_error1 = "loader constraint violation: loader (instance of ";
2182 linkage_error2 = ") previously initiated loading for a different type with name \"";
2183 }
2184 }
2185 }
2186
2187 // Throw error now if needed (cannot throw while holding
2188 // SystemDictionary_lock because of rank ordering)
2189
2190 if (linkage_error1) {
2191 ResourceMark rm(THREAD);
2192 const char* class_loader_name = loader_name(class_loader());
2193 char* type_name = k->name()->as_C_string();
2194 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2195 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2196 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2197 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2198 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2199 }
2200 }
2201
2202
2203 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2204 // have been called.
2205 void SystemDictionary::update_dictionary(unsigned int d_hash,
2206 int p_index, unsigned int p_hash,
2207 InstanceKlass* k,
2208 Handle class_loader,
2209 TRAPS) {
2210 // Compile_lock prevents systemDictionary updates during compilations
2211 assert_locked_or_safepoint(Compile_lock);
2212 Symbol* name = k->name();
2213 ClassLoaderData *loader_data = class_loader_data(class_loader);
2214
2215 {
2216 MutexLocker mu1(SystemDictionary_lock, THREAD);
2217
2218 // See whether biased locking is enabled and if so set it for this
2219 // klass.
2220 // Note that this must be done past the last potential blocking
2221 // point / safepoint. We enable biased locking lazily using a
2222 // VM_Operation to iterate the SystemDictionary and installing the
2223 // biasable mark word into each InstanceKlass's prototype header.
2224 // To avoid race conditions where we accidentally miss enabling the
2225 // optimization for one class in the process of being added to the
2226 // dictionary, we must not safepoint after the test of
2227 // BiasedLocking::enabled().
2228 if (UseBiasedLocking && BiasedLocking::enabled()) {
2229 // Set biased locking bit for all loaded classes; it will be
2230 // cleared if revocation occurs too often for this type
2231 // NOTE that we must only do this when the class is initally
2232 // defined, not each time it is referenced from a new class loader
2233 if (k->class_loader() == class_loader()) {
2234 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2235 }
2236 }
2237
2238 // Make a new dictionary entry.
2239 Dictionary* dictionary = loader_data->dictionary();
2240 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2241 if (sd_check == NULL) {
2242 dictionary->add_klass(d_hash, name, k);
2243 notice_modification();
2244 }
2245 #ifdef ASSERT
2246 sd_check = find_class(d_hash, name, dictionary);
2247 assert (sd_check != NULL, "should have entry in dictionary");
2248 // Note: there may be a placeholder entry: for circularity testing
2249 // or for parallel defines
2250 #endif
2251 SystemDictionary_lock->notify_all();
2252 }
2253 }
2254
2255
2256 // Try to find a class name using the loader constraints. The
2257 // loader constraints might know about a class that isn't fully loaded
2258 // yet and these will be ignored.
2259 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2260 Symbol* class_name, Handle class_loader, TRAPS) {
2261
2262 // First see if it has been loaded directly.
2263 // Force the protection domain to be null. (This removes protection checks.)
2264 Handle no_protection_domain;
2265 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2266 no_protection_domain, CHECK_NULL);
2267 if (klass != NULL)
2268 return klass;
2269
2270 // Now look to see if it has been loaded elsewhere, and is subject to
2271 // a loader constraint that would require this loader to return the
2272 // klass that is already loaded.
2273 if (FieldType::is_array(class_name)) {
2274 // For array classes, their Klass*s are not kept in the
2275 // constraint table. The element Klass*s are.
2276 FieldArrayInfo fd;
2277 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2278 if (t != T_OBJECT) {
2279 klass = Universe::typeArrayKlassObj(t);
2280 } else {
2281 MutexLocker mu(SystemDictionary_lock, THREAD);
2282 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2283 }
2284 // If element class already loaded, allocate array klass
2285 if (klass != NULL) {
2286 klass = klass->array_klass_or_null(fd.dimension());
2287 }
2288 } else {
2289 MutexLocker mu(SystemDictionary_lock, THREAD);
2290 // Non-array classes are easy: simply check the constraint table.
2291 klass = constraints()->find_constrained_klass(class_name, class_loader);
2292 }
2293
2294 return klass;
2295 }
2296
2297
2298 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2299 Handle class_loader1,
2300 Handle class_loader2,
2301 Thread* THREAD) {
2302 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2303 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2304
2305 Symbol* constraint_name = NULL;
2306 if (!FieldType::is_array(class_name)) {
2307 constraint_name = class_name;
2308 } else {
2309 // For array classes, their Klass*s are not kept in the
2310 // constraint table. The element classes are.
2311 FieldArrayInfo fd;
2312 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2313 // primitive types always pass
2314 if (t != T_OBJECT) {
2315 return true;
2316 } else {
2317 constraint_name = fd.object_key();
2318 }
2319 }
2320
2321 Dictionary* dictionary1 = loader_data1->dictionary();
2322 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2323
2324 Dictionary* dictionary2 = loader_data2->dictionary();
2325 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2326
2327 {
2328 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2329 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2330 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2331 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2332 klass2, class_loader2);
2333 }
2334 }
2335
2336 // Add entry to resolution error table to record the error when the first
2337 // attempt to resolve a reference to a class has failed.
2338 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2339 Symbol* error, Symbol* message) {
2340 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2341 int index = resolution_errors()->hash_to_index(hash);
2342 {
2343 MutexLocker ml(SystemDictionary_lock, Thread::current());
2344 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2345 }
2346 }
2347
2348 // Delete a resolution error for RedefineClasses for a constant pool is going away
2349 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2350 resolution_errors()->delete_entry(pool);
2351 }
2352
2353 // Lookup resolution error table. Returns error if found, otherwise NULL.
2354 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2355 Symbol** message) {
2356 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2357 int index = resolution_errors()->hash_to_index(hash);
2358 {
2359 MutexLocker ml(SystemDictionary_lock, Thread::current());
2360 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2361 if (entry != NULL) {
2362 *message = entry->message();
2363 return entry->error();
2364 } else {
2365 return NULL;
2366 }
2367 }
2368 }
2369
2370
2371 // Signature constraints ensure that callers and callees agree about
2372 // the meaning of type names in their signatures. This routine is the
2373 // intake for constraints. It collects them from several places:
2374 //
2375 // * LinkResolver::resolve_method (if check_access is true) requires
2376 // that the resolving class (the caller) and the defining class of
2377 // the resolved method (the callee) agree on each type in the
2378 // method's signature.
2379 //
2380 // * LinkResolver::resolve_interface_method performs exactly the same
2381 // checks.
2382 //
2383 // * LinkResolver::resolve_field requires that the constant pool
2384 // attempting to link to a field agree with the field's defining
2385 // class about the type of the field signature.
2386 //
2387 // * klassVtable::initialize_vtable requires that, when a class
2388 // overrides a vtable entry allocated by a superclass, that the
2389 // overriding method (i.e., the callee) agree with the superclass
2390 // on each type in the method's signature.
2391 //
2392 // * klassItable::initialize_itable requires that, when a class fills
2393 // in its itables, for each non-abstract method installed in an
2394 // itable, the method (i.e., the callee) agree with the interface
2395 // on each type in the method's signature.
2396 //
2397 // All those methods have a boolean (check_access, checkconstraints)
2398 // which turns off the checks. This is used from specialized contexts
2399 // such as bootstrapping, dumping, and debugging.
2400 //
2401 // No direct constraint is placed between the class and its
2402 // supertypes. Constraints are only placed along linked relations
2403 // between callers and callees. When a method overrides or implements
2404 // an abstract method in a supertype (superclass or interface), the
2405 // constraints are placed as if the supertype were the caller to the
2406 // overriding method. (This works well, since callers to the
2407 // supertype have already established agreement between themselves and
2408 // the supertype.) As a result of all this, a class can disagree with
2409 // its supertype about the meaning of a type name, as long as that
2410 // class neither calls a relevant method of the supertype, nor is
2411 // called (perhaps via an override) from the supertype.
2412 //
2413 //
2414 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2415 //
2416 // Make sure all class components (including arrays) in the given
2417 // signature will be resolved to the same class in both loaders.
2418 // Returns the name of the type that failed a loader constraint check, or
2419 // NULL if no constraint failed. No exception except OOME is thrown.
2420 // Arrays are not added to the loader constraint table, their elements are.
2421 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2422 Handle loader1, Handle loader2,
2423 bool is_method, TRAPS) {
2424 // Nothing to do if loaders are the same.
2425 if (loader1() == loader2()) {
2426 return NULL;
2427 }
2428
2429 SignatureStream sig_strm(signature, is_method);
2430 while (!sig_strm.is_done()) {
2431 if (sig_strm.is_object()) {
2432 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2433 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2434 return sig;
2435 }
2436 }
2437 sig_strm.next();
2438 }
2439 return NULL;
2440 }
2441
2442
2443 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2444 Symbol* signature,
2445 TRAPS) {
2446 methodHandle empty;
2447 assert(MethodHandles::is_signature_polymorphic(iid) &&
2448 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2449 iid != vmIntrinsics::_invokeGeneric,
2450 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2451
2452 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2453 int index = invoke_method_table()->hash_to_index(hash);
2454 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2455 methodHandle m;
2456 if (spe == NULL || spe->method() == NULL) {
2457 spe = NULL;
2458 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2459 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2460 if (!Arguments::is_interpreter_only()) {
2461 // Generate a compiled form of the MH intrinsic.
2462 AdapterHandlerLibrary::create_native_wrapper(m);
2463 // Check if have the compiled code.
2464 if (!m->has_compiled_code()) {
2465 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2466 "Out of space in CodeCache for method handle intrinsic", empty);
2467 }
2468 }
2469 // Now grab the lock. We might have to throw away the new method,
2470 // if a racing thread has managed to install one at the same time.
2471 {
2472 MutexLocker ml(SystemDictionary_lock, THREAD);
2473 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2474 if (spe == NULL)
2475 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2476 if (spe->method() == NULL)
2477 spe->set_method(m());
2478 }
2479 }
2480
2481 assert(spe != NULL && spe->method() != NULL, "");
2482 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2483 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2484 "MH intrinsic invariant");
2485 return spe->method();
2486 }
2487
2488 // Helper for unpacking the return value from linkMethod and linkCallSite.
2489 static methodHandle unpack_method_and_appendix(Handle mname,
2490 Klass* accessing_klass,
2491 objArrayHandle appendix_box,
2492 Handle* appendix_result,
2493 TRAPS) {
2494 methodHandle empty;
2495 if (mname.not_null()) {
2496 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2497 if (m != NULL) {
2498 oop appendix = appendix_box->obj_at(0);
2499 if (TraceMethodHandles) {
2500 #ifndef PRODUCT
2501 ttyLocker ttyl;
2502 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2503 m->print();
2504 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2505 tty->cr();
2506 #endif //PRODUCT
2507 }
2508 (*appendix_result) = Handle(THREAD, appendix);
2509 // the target is stored in the cpCache and if a reference to this
2510 // MemberName is dropped we need a way to make sure the
2511 // class_loader containing this method is kept alive.
2512 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2513 this_key->record_dependency(m->method_holder());
2514 return methodHandle(THREAD, m);
2515 }
2516 }
2517 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2518 return empty;
2519 }
2520
2521 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2522 Symbol* name,
2523 Symbol* signature,
2524 Klass* accessing_klass,
2525 Handle *appendix_result,
2526 Handle *method_type_result,
2527 TRAPS) {
2528 methodHandle empty;
2529 assert(THREAD->can_call_java() ,"");
2530 Handle method_type =
2531 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2532
2533 int ref_kind = JVM_REF_invokeVirtual;
2534 oop name_oop = StringTable::intern(name, CHECK_(empty));
2535 Handle name_str (THREAD, name_oop);
2536 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2537 assert(appendix_box->obj_at(0) == NULL, "");
2538
2539 // This should not happen. JDK code should take care of that.
2540 if (accessing_klass == NULL || method_type.is_null()) {
2541 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2542 }
2543
2544 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2545 JavaCallArguments args;
2546 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2547 args.push_int(ref_kind);
2548 args.push_oop(Handle(THREAD, klass->java_mirror()));
2549 args.push_oop(name_str);
2550 args.push_oop(method_type);
2551 args.push_oop(appendix_box);
2552 JavaValue result(T_OBJECT);
2553 JavaCalls::call_static(&result,
2554 SystemDictionary::MethodHandleNatives_klass(),
2555 vmSymbols::linkMethod_name(),
2556 vmSymbols::linkMethod_signature(),
2557 &args, CHECK_(empty));
2558 Handle mname(THREAD, (oop) result.get_jobject());
2559 (*method_type_result) = method_type;
2560 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2561 }
2562
2563 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2564 // We must ensure that all class loaders everywhere will reach this class, for any client.
2565 // This is a safe bet for public classes in java.lang, such as Object and String.
2566 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2567 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2568 static bool is_always_visible_class(oop mirror) {
2569 Klass* klass = java_lang_Class::as_Klass(mirror);
2570 if (klass->is_objArray_klass()) {
2571 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2572 }
2573 if (klass->is_typeArray_klass()) {
2574 return true; // primitive array
2575 }
2576 assert(klass->is_instance_klass(), "%s", klass->external_name());
2577 return klass->is_public() &&
2578 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2579 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2580 }
2581
2582
2583 // Return the Java mirror (java.lang.Class instance) for a single-character
2584 // descriptor. This result, when available, is the same as produced by the
2585 // heavier API point of the same name that takes a Symbol.
2586 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2587 return java_lang_Class::primitive_mirror(char2type(signature_char));
2588 }
2589
2590 // Find or construct the Java mirror (java.lang.Class instance) for a
2591 // for the given field type signature, as interpreted relative to the
2592 // given class loader. Handles primitives, void, references, arrays,
2593 // and all other reflectable types, except method types.
2594 // N.B. Code in reflection should use this entry point.
2595 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2596 Klass* accessing_klass,
2597 Handle class_loader,
2598 Handle protection_domain,
2599 SignatureStream::FailureMode failure_mode,
2600 TRAPS) {
2601 Handle empty;
2602
2603 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2604 "one or the other, or perhaps neither");
2605
2606 Symbol* type = signature;
2607
2608 // What we have here must be a valid field descriptor,
2609 // and all valid field descriptors are supported.
2610 // Produce the same java.lang.Class that reflection reports.
2611 if (type->utf8_length() == 1) {
2612
2613 // It's a primitive. (Void has a primitive mirror too.)
2614 char ch = (char) type->byte_at(0);
2615 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2616 return Handle(THREAD, find_java_mirror_for_type(ch));
2617
2618 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2619
2620 // It's a reference type.
2621 if (accessing_klass != NULL) {
2622 class_loader = Handle(THREAD, accessing_klass->class_loader());
2623 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2624 }
2625 Klass* constant_type_klass;
2626 if (failure_mode == SignatureStream::ReturnNull) {
2627 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2628 CHECK_(empty));
2629 } else {
2630 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2631 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2632 throw_error, CHECK_(empty));
2633 }
2634 if (constant_type_klass == NULL) {
2635 return Handle(); // report failure this way
2636 }
2637 Handle mirror(THREAD, constant_type_klass->java_mirror());
2638
2639 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2640 if (accessing_klass != NULL) {
2641 Klass* sel_klass = constant_type_klass;
2642 bool fold_type_to_class = true;
2643 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2644 fold_type_to_class, CHECK_(empty));
2645 }
2646
2647 return mirror;
2648
2649 }
2650
2651 // Fall through to an error.
2652 assert(false, "unsupported mirror syntax");
2653 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2654 }
2655
2656
2657 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2658 // signature, as interpreted relative to the given class loader.
2659 // Because of class loader constraints, all method handle usage must be
2660 // consistent with this loader.
2661 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2662 Klass* accessing_klass,
2663 TRAPS) {
2664 Handle empty;
2665 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2666 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2667 int index = invoke_method_table()->hash_to_index(hash);
2668 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2669 if (spe != NULL && spe->method_type() != NULL) {
2670 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2671 return Handle(THREAD, spe->method_type());
2672 } else if (!THREAD->can_call_java()) {
2673 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2674 return Handle(); // do not attempt from within compiler, unless it was cached
2675 }
2676
2677 Handle class_loader, protection_domain;
2678 if (accessing_klass != NULL) {
2679 class_loader = Handle(THREAD, accessing_klass->class_loader());
2680 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2681 }
2682 bool can_be_cached = true;
2683 int npts = ArgumentCount(signature).size();
2684 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2685 int arg = 0;
2686 Handle rt; // the return type from the signature
2687 ResourceMark rm(THREAD);
2688 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2689 oop mirror = NULL;
2690 if (can_be_cached) {
2691 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2692 mirror = ss.as_java_mirror(Handle(), Handle(),
2693 SignatureStream::ReturnNull, CHECK_(empty));
2694 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2695 // Fall back to accessing_klass context.
2696 can_be_cached = false;
2697 }
2698 }
2699 if (!can_be_cached) {
2700 // Resolve, throwing a real error if it doesn't work.
2701 mirror = ss.as_java_mirror(class_loader, protection_domain,
2702 SignatureStream::NCDFError, CHECK_(empty));
2703 }
2704 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2705 if (ss.at_return_type())
2706 rt = Handle(THREAD, mirror);
2707 else
2708 pts->obj_at_put(arg++, mirror);
2709
2710 // Check accessibility.
2711 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2712 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2713 mirror = NULL; // safety
2714 // Emulate ConstantPool::verify_constant_pool_resolve.
2715 bool fold_type_to_class = true;
2716 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2717 fold_type_to_class, CHECK_(empty));
2718 }
2719 }
2720 assert(arg == npts, "");
2721
2722 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2723 JavaCallArguments args(Handle(THREAD, rt()));
2724 args.push_oop(pts);
2725 JavaValue result(T_OBJECT);
2726 JavaCalls::call_static(&result,
2727 SystemDictionary::MethodHandleNatives_klass(),
2728 vmSymbols::findMethodHandleType_name(),
2729 vmSymbols::findMethodHandleType_signature(),
2730 &args, CHECK_(empty));
2731 Handle method_type(THREAD, (oop) result.get_jobject());
2732
2733 if (can_be_cached) {
2734 // We can cache this MethodType inside the JVM.
2735 MutexLocker ml(SystemDictionary_lock, THREAD);
2736 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2737 if (spe == NULL)
2738 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2739 if (spe->method_type() == NULL) {
2740 spe->set_method_type(method_type());
2741 }
2742 }
2743
2744 // report back to the caller with the MethodType
2745 return method_type;
2746 }
2747
2748 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2749 Klass* accessing_klass,
2750 TRAPS) {
2751 Handle empty;
2752 ResourceMark rm(THREAD);
2753 SignatureStream ss(signature, /*is_method=*/ false);
2754 if (!ss.is_done()) {
2755 Handle class_loader, protection_domain;
2756 if (accessing_klass != NULL) {
2757 class_loader = Handle(THREAD, accessing_klass->class_loader());
2758 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2759 }
2760 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2761 ss.next();
2762 if (ss.is_done()) {
2763 return Handle(THREAD, mirror);
2764 }
2765 }
2766 return empty;
2767 }
2768
2769 // Ask Java code to find or construct a method handle constant.
2770 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2771 int ref_kind, //e.g., JVM_REF_invokeVirtual
2772 Klass* callee,
2773 Symbol* name,
2774 Symbol* signature,
2775 TRAPS) {
2776 Handle empty;
2777 if (caller == NULL) {
2778 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2779 }
2780 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2781 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2782
2783 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2784 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2785 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2786 java_lang_invoke_MemberName::set_name (mname(), name_str());
2787 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2788 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2789
2790 if (ref_kind == JVM_REF_invokeVirtual &&
2791 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2792 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2793 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2794 // They are public signature polymorphic methods, but require appendix argument
2795 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2796 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2797 } else {
2798 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2799 }
2800
2801 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2802 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2803
2804 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2805 JavaCallArguments args;
2806 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2807 args.push_int(ref_kind);
2808 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2809 args.push_oop(name_str);
2810 args.push_oop(type);
2811 JavaValue result(T_OBJECT);
2812 JavaCalls::call_static(&result,
2813 SystemDictionary::MethodHandleNatives_klass(),
2814 vmSymbols::linkMethodHandleConstant_name(),
2815 vmSymbols::linkMethodHandleConstant_signature(),
2816 &args, CHECK_(empty));
2817 return Handle(THREAD, (oop) result.get_jobject());
2818 }
2819
2820 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2821 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2822 int condy_index,
2823 Handle bootstrap_specifier,
2824 Symbol* name,
2825 Symbol* type,
2826 TRAPS) {
2827 Handle empty;
2828 Handle bsm, info;
2829 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2830 bsm = bootstrap_specifier;
2831 } else {
2832 assert(bootstrap_specifier->is_objArray(), "");
2833 objArrayOop args = (objArrayOop) bootstrap_specifier();
2834 assert(args->length() == 2, "");
2835 bsm = Handle(THREAD, args->obj_at(0));
2836 info = Handle(THREAD, args->obj_at(1));
2837 }
2838 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2839 "caller must supply a valid BSM");
2840
2841 // This should not happen. JDK code should take care of that.
2842 if (caller == NULL) {
2843 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2844 }
2845
2846 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2847
2848 // Resolve the constant type in the context of the caller class
2849 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2850 CHECK_(empty));
2851
2852 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2853 JavaCallArguments args;
2854 args.push_oop(Handle(THREAD, caller->java_mirror()));
2855 args.push_int(condy_index);
2856 args.push_oop(bsm);
2857 args.push_oop(constant_name);
2858 args.push_oop(type_mirror);
2859 args.push_oop(info);
2860 JavaValue result(T_OBJECT);
2861 JavaCalls::call_static(&result,
2862 SystemDictionary::MethodHandleNatives_klass(),
2863 vmSymbols::linkDynamicConstant_name(),
2864 vmSymbols::linkDynamicConstant_signature(),
2865 &args, CHECK_(empty));
2866
2867 return Handle(THREAD, (oop) result.get_jobject());
2868 }
2869
2870 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2871 // name and signature, as interpreted relative to the given class loader.
2872 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2873 int indy_index,
2874 Handle bootstrap_specifier,
2875 Symbol* name,
2876 Symbol* type,
2877 Handle *appendix_result,
2878 Handle *method_type_result,
2879 TRAPS) {
2880 methodHandle empty;
2881 Handle bsm, info;
2882 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2883 bsm = bootstrap_specifier;
2884 } else {
2885 objArrayOop args = (objArrayOop) bootstrap_specifier();
2886 assert(args->length() == 2, "");
2887 bsm = Handle(THREAD, args->obj_at(0));
2888 info = Handle(THREAD, args->obj_at(1));
2889 }
2890 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2891 "caller must supply a valid BSM");
2892
2893 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2894 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2895
2896 // This should not happen. JDK code should take care of that.
2897 if (caller == NULL || method_type.is_null()) {
2898 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2899 }
2900
2901 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2902 assert(appendix_box->obj_at(0) == NULL, "");
2903
2904 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2905 JavaCallArguments args;
2906 args.push_oop(Handle(THREAD, caller->java_mirror()));
2907 args.push_int(indy_index);
2908 args.push_oop(bsm);
2909 args.push_oop(method_name);
2910 args.push_oop(method_type);
2911 args.push_oop(info);
2912 args.push_oop(appendix_box);
2913 JavaValue result(T_OBJECT);
2914 JavaCalls::call_static(&result,
2915 SystemDictionary::MethodHandleNatives_klass(),
2916 vmSymbols::linkCallSite_name(),
2917 vmSymbols::linkCallSite_signature(),
2918 &args, CHECK_(empty));
2919 Handle mname(THREAD, (oop) result.get_jobject());
2920 (*method_type_result) = method_type;
2921 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2922 }
2923
2924 // Protection domain cache table handling
2925
2926 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2927 return _pd_cache_table->get(protection_domain);
2928 }
2929
2930 #if INCLUDE_CDS
2931 void SystemDictionary::reorder_dictionary_for_sharing() {
2932 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2933 }
2934 #endif
2935
2936 size_t SystemDictionary::count_bytes_for_buckets() {
2937 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2938 }
2939
2940 size_t SystemDictionary::count_bytes_for_table() {
2941 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2942 }
2943
2944 void SystemDictionary::copy_buckets(char* top, char* end) {
2945 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2946 }
2947
2948 void SystemDictionary::copy_table(char* top, char* end) {
2949 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2950 }
2951
2952 // ----------------------------------------------------------------------------
2953 void SystemDictionary::print_shared(outputStream *st) {
2954 shared_dictionary()->print_on(st);
2955 }
2956
2957 void SystemDictionary::print_on(outputStream *st) {
2958 if (shared_dictionary() != NULL) {
2959 st->print_cr("Shared Dictionary");
2960 shared_dictionary()->print_on(st);
2961 st->cr();
2962 }
2963
2964 GCMutexLocker mu(SystemDictionary_lock);
2965
2966 ClassLoaderDataGraph::print_dictionary(st);
2967
2968 // Placeholders
2969 placeholders()->print_on(st);
2970 st->cr();
2971
2972 // loader constraints - print under SD_lock
2973 constraints()->print_on(st);
2974 st->cr();
2975
2976 _pd_cache_table->print_on(st);
2977 st->cr();
2978 }
2979
2980 void SystemDictionary::verify() {
2981 guarantee(constraints() != NULL,
2982 "Verify of loader constraints failed");
2983 guarantee(placeholders()->number_of_entries() >= 0,
2984 "Verify of placeholders failed");
2985
2986 GCMutexLocker mu(SystemDictionary_lock);
2987
2988 // Verify dictionary
2989 ClassLoaderDataGraph::verify_dictionary();
2990
2991 placeholders()->verify();
2992
2993 // Verify constraint table
2994 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2995 constraints()->verify(placeholders());
2996
2997 _pd_cache_table->verify();
2998 }
2999
3000 void SystemDictionary::dump(outputStream *st, bool verbose) {
3001 assert_locked_or_safepoint(SystemDictionary_lock);
3002 if (verbose) {
3003 print_on(st);
3004 } else {
3005 if (shared_dictionary() != NULL) {
3006 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3007 }
3008 ClassLoaderDataGraph::print_dictionary_statistics(st);
3009 placeholders()->print_table_statistics(st, "Placeholder Table");
3010 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3011 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3012 }
3013 }
3014
3015 // Utility for dumping dictionaries.
3016 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3017 DCmdWithParser(output, heap),
3018 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3019 "BOOLEAN", false, "false") {
3020 _dcmdparser.add_dcmd_option(&_verbose);
3021 }
3022
3023 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3024 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3025 _verbose.value());
3026 VMThread::execute(&dumper);
3027 }
3028
3029 int SystemDictionaryDCmd::num_arguments() {
3030 ResourceMark rm;
3031 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3032 if (dcmd != NULL) {
3033 DCmdMark mark(dcmd);
3034 return dcmd->_dcmdparser.num_arguments();
3035 } else {
3036 return 0;
3037 }
3038 }
3039
3040 class CombineDictionariesClosure : public CLDClosure {
3041 private:
3042 Dictionary* _master_dictionary;
3043 public:
3044 CombineDictionariesClosure(Dictionary* master_dictionary) :
3045 _master_dictionary(master_dictionary) {}
3046 void do_cld(ClassLoaderData* cld) {
3047 ResourceMark rm;
3048 if (cld->is_anonymous()) {
3049 return;
3050 }
3051 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3052 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3053 Dictionary* curr_dictionary = cld->dictionary();
3054 DictionaryEntry* p = curr_dictionary->bucket(i);
3055 while (p != NULL) {
3056 Symbol* name = p->instance_klass()->name();
3057 unsigned int d_hash = _master_dictionary->compute_hash(name);
3058 int d_index = _master_dictionary->hash_to_index(d_hash);
3059 DictionaryEntry* next = p->next();
3060 if (p->literal()->class_loader_data() != cld) {
3061 // This is an initiating class loader entry; don't use it
3062 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3063 curr_dictionary->free_entry(p);
3064 } else {
3065 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3066 curr_dictionary->unlink_entry(p);
3067 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3068 _master_dictionary->add_entry(d_index, p);
3069 }
3070 p = next;
3071 }
3072 *curr_dictionary->bucket_addr(i) = NULL;
3073 }
3074 }
3075 }
3076 };
3077
3078 // Combining platform and system loader dictionaries into boot loader dictionary.
3079 // During run time, we only have one shared dictionary.
3080 void SystemDictionary::combine_shared_dictionaries() {
3081 assert(DumpSharedSpaces, "dump time only");
3082 // If AppCDS isn't enabled, we only dump the classes in the boot loader dictionary
3083 // into the shared archive.
3084 if (UseAppCDS) {
3085 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3086 CombineDictionariesClosure cdc(master_dictionary);
3087 ClassLoaderDataGraph::cld_do(&cdc);
3088 }
3089
3090 // These tables are no longer valid or necessary. Keeping them around will
3091 // cause SystemDictionary::verify() to fail. Let's empty them.
3092 _placeholders = new PlaceholderTable(_placeholder_table_size);
3093 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3094
3095 NOT_PRODUCT(SystemDictionary::verify());
3096 }
3097
3098 // caller needs ResourceMark
3099 const char* SystemDictionary::loader_name(const oop loader) {
3100 return ((loader) == NULL ? "<bootloader>" :
3101 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3102 }
3103
3104 // caller needs ResourceMark
3105 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3106 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3107 SystemDictionary::loader_name(loader_data->class_loader()));
3108 }