1 /*
2 * Copyright (c) 1997, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "gc/shared/oopStorage.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "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/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_checkPackageAccess = false;
112
113 // lazily initialized klass variables
114 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
115
116 // Default ProtectionDomainCacheSize value
117
118 const int defaultProtectionDomainCacheSize = 1009;
119
120 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
121
122
123 // ----------------------------------------------------------------------------
124 // Java-level SystemLoader and PlatformLoader
125
126 oop SystemDictionary::java_system_loader() {
127 return _java_system_loader;
128 }
129
130 oop SystemDictionary::java_platform_loader() {
131 return _java_platform_loader;
132 }
133
134 void SystemDictionary::compute_java_loaders(TRAPS) {
135 JavaValue result(T_OBJECT);
136 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
137 JavaCalls::call_static(&result,
138 class_loader_klass,
139 vmSymbols::getSystemClassLoader_name(),
140 vmSymbols::void_classloader_signature(),
141 CHECK);
142
143 _java_system_loader = (oop)result.get_jobject();
144
145 JavaCalls::call_static(&result,
146 class_loader_klass,
147 vmSymbols::getPlatformClassLoader_name(),
148 vmSymbols::void_classloader_signature(),
149 CHECK);
150
151 _java_platform_loader = (oop)result.get_jobject();
152
153 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
154 }
155
156 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
157 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
158 return ClassLoaderDataGraph::find_or_create(class_loader);
159 }
160
161 // ----------------------------------------------------------------------------
162 // Parallel class loading check
163
164 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
165 if (class_loader.is_null()) return true;
166 if (AlwaysLockClassLoader) return false;
167 return java_lang_ClassLoader::parallelCapable(class_loader());
168 }
169 // ----------------------------------------------------------------------------
170 // ParallelDefineClass flag does not apply to bootclass loader
171 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
172 if (class_loader.is_null()) return false;
173 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
174 return true;
175 }
176 return false;
177 }
178
179 // Returns true if the passed class loader is the builtin application class loader
180 // or a custom system class loader. A customer system class loader can be
181 // specified via -Djava.system.class.loader.
182 bool SystemDictionary::is_system_class_loader(oop class_loader) {
183 if (class_loader == NULL) {
184 return false;
185 }
186 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
187 oopDesc::equals(class_loader, _java_system_loader));
188 }
189
190 // Returns true if the passed class loader is the platform class loader.
191 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
192 if (class_loader == NULL) {
193 return false;
194 }
195 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
196 }
197
198 // ----------------------------------------------------------------------------
199 // Resolving of classes
200
201 // Forwards to resolve_or_null
202
203 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
204 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
205 if (HAS_PENDING_EXCEPTION || klass == NULL) {
206 // can return a null klass
207 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
208 }
209 return klass;
210 }
211
212 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
213 bool throw_error,
214 Klass* klass, TRAPS) {
215 if (HAS_PENDING_EXCEPTION) {
216 // If we have a pending exception we forward it to the caller, unless throw_error is true,
217 // in which case we have to check whether the pending exception is a ClassNotFoundException,
218 // and if so convert it to a NoClassDefFoundError
219 // And chain the original ClassNotFoundException
220 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
221 ResourceMark rm(THREAD);
222 assert(klass == NULL, "Should not have result with exception pending");
223 Handle e(THREAD, PENDING_EXCEPTION);
224 CLEAR_PENDING_EXCEPTION;
225 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
226 } else {
227 return NULL;
228 }
229 }
230 // Class not found, throw appropriate error or exception depending on value of throw_error
231 if (klass == NULL) {
232 ResourceMark rm(THREAD);
233 if (throw_error) {
234 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
235 } else {
236 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
237 }
238 }
239 return klass;
240 }
241
242
243 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
244 bool throw_error, TRAPS)
245 {
246 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
247 }
248
249
250 // Forwards to resolve_instance_class_or_null
251
252 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
253 assert(THREAD->can_call_java(),
254 "can not load classes with compiler thread: class=%s, classloader=%s",
255 class_name->as_C_string(),
256 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
257 if (FieldType::is_array(class_name)) {
258 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
259 } else if (FieldType::is_obj(class_name)) {
260 ResourceMark rm(THREAD);
261 // Ignore wrapping L and ;.
262 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
263 class_name->utf8_length() - 2, CHECK_NULL);
264 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
265 } else {
266 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
267 }
268 }
269
270 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
271 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
272 }
273
274 // Forwards to resolve_instance_class_or_null
275
276 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
277 Handle class_loader,
278 Handle protection_domain,
279 TRAPS) {
280 assert(FieldType::is_array(class_name), "must be array");
281 Klass* k = NULL;
282 FieldArrayInfo fd;
283 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
284 // of this call
285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
286 if (t == T_OBJECT) {
287 // naked oop "k" is OK here -- we assign back into it
288 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
289 class_loader,
290 protection_domain,
291 CHECK_NULL);
292 if (k != NULL) {
293 k = k->array_klass(fd.dimension(), CHECK_NULL);
294 }
295 } else {
296 k = Universe::typeArrayKlassObj(t);
297 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
298 }
299 return k;
300 }
301
302
303 // Must be called for any super-class or super-interface resolution
304 // during class definition to allow class circularity checking
305 // super-interface callers:
306 // parse_interfaces - for defineClass & jvmtiRedefineClasses
307 // super-class callers:
308 // ClassFileParser - for defineClass & jvmtiRedefineClasses
309 // load_shared_class - while loading a class from shared archive
310 // resolve_instance_class_or_null:
311 // via: handle_parallel_super_load
312 // when resolving a class that has an existing placeholder with
313 // a saved superclass [i.e. a defineClass is currently in progress]
314 // if another thread is trying to resolve the class, it must do
315 // super-class checks on its own thread to catch class circularity
316 // This last call is critical in class circularity checking for cases
317 // where classloading is delegated to different threads and the
318 // classloader lock is released.
319 // Take the case: Base->Super->Base
320 // 1. If thread T1 tries to do a defineClass of class Base
321 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
322 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
323 // so it tries to load Super
324 // 3. If we load the class internally, or user classloader uses same thread
325 // loadClassFromxxx or defineClass via parseClassFile Super ...
326 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
327 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
328 // 3.4 calls resolve_super_or_fail Base
329 // 3.5 finds T1,Base -> throws class circularity
330 //OR 4. If T2 tries to resolve Super via defineClass Super ...
331 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
332 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
333 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
334 // 4.4 finds T2, Super -> throws class circularity
335 // Must be called, even if superclass is null, since this is
336 // where the placeholder entry is created which claims this
337 // thread is loading this class/classloader.
338 // Be careful when modifying this code: once you have run
339 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
340 // you need to find_and_remove it before returning.
341 // So be careful to not exit with a CHECK_ macro betweeen these calls.
342 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
343 Symbol* class_name,
344 Handle class_loader,
345 Handle protection_domain,
346 bool is_superclass,
347 TRAPS) {
348 #if INCLUDE_CDS
349 if (DumpSharedSpaces) {
350 // Special processing for CDS dump time.
351 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
352 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
353 if (k) {
354 return k;
355 }
356 }
357 #endif // INCLUDE_CDS
358
359 // Double-check, if child class is already loaded, just return super-class,interface
360 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
361 // dictionary.
362 // Make sure there's a placeholder for the *child* before resolving.
363 // Used as a claim that this thread is currently loading superclass/classloader
364 // Used here for ClassCircularity checks and also for heap verification
365 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
366 // Must check ClassCircularity before checking if super class is already loaded.
367 //
368 // We might not already have a placeholder if this child_name was
369 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
370 // the name of the class might not be known until the stream is actually
371 // parsed.
372 // Bugs 4643874, 4715493
373
374 ClassLoaderData* loader_data = class_loader_data(class_loader);
375 Dictionary* dictionary = loader_data->dictionary();
376 unsigned int d_hash = dictionary->compute_hash(child_name);
377 unsigned int p_hash = placeholders()->compute_hash(child_name);
378 int p_index = placeholders()->hash_to_index(p_hash);
379 // can't throw error holding a lock
380 bool child_already_loaded = false;
381 bool throw_circularity_error = false;
382 {
383 MutexLocker mu(SystemDictionary_lock, THREAD);
384 Klass* childk = find_class(d_hash, child_name, dictionary);
385 Klass* quicksuperk;
386 // to support // loading: if child done loading, just return superclass
387 // if class_name, & class_loader don't match:
388 // if initial define, SD update will give LinkageError
389 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
390 // so we don't throw an exception here.
391 // see: nsk redefclass014 & java.lang.instrument Instrument032
392 if ((childk != NULL ) && (is_superclass) &&
393 ((quicksuperk = childk->super()) != NULL) &&
394
395 ((quicksuperk->name() == class_name) &&
396 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
397 return quicksuperk;
398 } else {
399 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
400 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
401 throw_circularity_error = true;
402 }
403 }
404 if (!throw_circularity_error) {
405 // Be careful not to exit resolve_super
406 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
407 }
408 }
409 if (throw_circularity_error) {
410 ResourceMark rm(THREAD);
411 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
412 }
413
414 // java.lang.Object should have been found above
415 assert(class_name != NULL, "null super class for resolving");
416 // Resolve the super class or interface, check results on return
417 Klass* superk = SystemDictionary::resolve_or_null(class_name,
418 class_loader,
419 protection_domain,
420 THREAD);
421
422 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
423 // It is no longer necessary to keep the placeholder table alive until update_dictionary
424 // or error. GC used to walk the placeholder table as strong roots.
425 // The instanceKlass is kept alive because the class loader is on the stack,
426 // which keeps the loader_data alive, as well as all instanceKlasses in
427 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
428 {
429 MutexLocker mu(SystemDictionary_lock, THREAD);
430 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
431 SystemDictionary_lock->notify_all();
432 }
433 if (HAS_PENDING_EXCEPTION || superk == NULL) {
434 // can null superk
435 superk = handle_resolution_exception(class_name, true, superk, THREAD);
436 }
437
438 return superk;
439 }
440
441 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
442 Handle class_loader,
443 Handle protection_domain,
444 TRAPS) {
445 if(!has_checkPackageAccess()) return;
446
447 // Now we have to call back to java to check if the initating class has access
448 JavaValue result(T_VOID);
449 LogTarget(Debug, protectiondomain) lt;
450 if (lt.is_enabled()) {
451 ResourceMark rm;
452 // Print out trace information
453 LogStream ls(lt);
454 ls.print_cr("Checking package access");
455 ls.print("class loader: "); class_loader()->print_value_on(&ls);
456 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
457 ls.print(" loading: "); klass->print_value_on(&ls);
458 ls.cr();
459 }
460
461 // This handle and the class_loader handle passed in keeps this class from
462 // being unloaded through several GC points.
463 // The class_loader handle passed in is the initiating loader.
464 Handle mirror(THREAD, klass->java_mirror());
465
466 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
467 JavaCalls::call_special(&result,
468 class_loader,
469 system_loader,
470 vmSymbols::checkPackageAccess_name(),
471 vmSymbols::class_protectiondomain_signature(),
472 mirror,
473 protection_domain,
474 THREAD);
475
476 if (HAS_PENDING_EXCEPTION) {
477 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
478 } else {
479 log_debug(protectiondomain)("granted");
480 }
481
482 if (HAS_PENDING_EXCEPTION) return;
483
484 // If no exception has been thrown, we have validated the protection domain
485 // Insert the protection domain of the initiating class into the set.
486 {
487 ClassLoaderData* loader_data = class_loader_data(class_loader);
488 Dictionary* dictionary = loader_data->dictionary();
489
490 Symbol* kn = klass->name();
491 unsigned int d_hash = dictionary->compute_hash(kn);
492
493 MutexLocker mu(SystemDictionary_lock, THREAD);
494 int d_index = dictionary->hash_to_index(d_hash);
495 dictionary->add_protection_domain(d_index, d_hash, klass,
496 protection_domain, THREAD);
497 }
498 }
499
500 // We only get here if this thread finds that another thread
501 // has already claimed the placeholder token for the current operation,
502 // but that other thread either never owned or gave up the
503 // object lock
504 // Waits on SystemDictionary_lock to indicate placeholder table updated
505 // On return, caller must recheck placeholder table state
506 //
507 // We only get here if
508 // 1) custom classLoader, i.e. not bootstrap classloader
509 // 2) custom classLoader has broken the class loader objectLock
510 // so another thread got here in parallel
511 //
512 // lockObject must be held.
513 // Complicated dance due to lock ordering:
514 // Must first release the classloader object lock to
515 // allow initial definer to complete the class definition
516 // and to avoid deadlock
517 // Reclaim classloader lock object with same original recursion count
518 // Must release SystemDictionary_lock after notify, since
519 // class loader lock must be claimed before SystemDictionary_lock
520 // to prevent deadlocks
521 //
522 // The notify allows applications that did an untimed wait() on
523 // the classloader object lock to not hang.
524 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
525 assert_lock_strong(SystemDictionary_lock);
526
527 bool calledholdinglock
528 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
529 assert(calledholdinglock,"must hold lock for notify");
530 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
531 ObjectSynchronizer::notifyall(lockObject, THREAD);
532 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
533 SystemDictionary_lock->wait();
534 SystemDictionary_lock->unlock();
535 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
536 SystemDictionary_lock->lock();
537 }
538
539 // If the class in is in the placeholder table, class loading is in progress
540 // For cases where the application changes threads to load classes, it
541 // is critical to ClassCircularity detection that we try loading
542 // the superclass on the same thread internally, so we do parallel
543 // super class loading here.
544 // This also is critical in cases where the original thread gets stalled
545 // even in non-circularity situations.
546 // Note: must call resolve_super_or_fail even if null super -
547 // to force placeholder entry creation for this class for circularity detection
548 // Caller must check for pending exception
549 // Returns non-null Klass* if other thread has completed load
550 // and we are done,
551 // If return null Klass* and no pending exception, the caller must load the class
552 InstanceKlass* SystemDictionary::handle_parallel_super_load(
553 Symbol* name, Symbol* superclassname, Handle class_loader,
554 Handle protection_domain, Handle lockObject, TRAPS) {
555
556 ClassLoaderData* loader_data = class_loader_data(class_loader);
557 Dictionary* dictionary = loader_data->dictionary();
558 unsigned int d_hash = dictionary->compute_hash(name);
559 unsigned int p_hash = placeholders()->compute_hash(name);
560 int p_index = placeholders()->hash_to_index(p_hash);
561
562 // superk is not used, resolve_super called for circularity check only
563 // This code is reached in two situations. One if this thread
564 // is loading the same class twice (e.g. ClassCircularity, or
565 // java.lang.instrument).
566 // The second is if another thread started the resolve_super first
567 // and has not yet finished.
568 // In both cases the original caller will clean up the placeholder
569 // entry on error.
570 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
571 superclassname,
572 class_loader,
573 protection_domain,
574 true,
575 CHECK_NULL);
576
577 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
578 // Serial class loaders and bootstrap classloader do wait for superclass loads
579 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
580 MutexLocker mu(SystemDictionary_lock, THREAD);
581 // Check if classloading completed while we were loading superclass or waiting
582 return find_class(d_hash, name, dictionary);
583 }
584
585 // must loop to both handle other placeholder updates
586 // and spurious notifications
587 bool super_load_in_progress = true;
588 PlaceholderEntry* placeholder;
589 while (super_load_in_progress) {
590 MutexLocker mu(SystemDictionary_lock, THREAD);
591 // Check if classloading completed while we were loading superclass or waiting
592 InstanceKlass* check = find_class(d_hash, name, dictionary);
593 if (check != NULL) {
594 // Klass is already loaded, so just return it
595 return check;
596 } else {
597 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
598 if (placeholder && placeholder->super_load_in_progress() ){
599 // We only get here if the application has released the
600 // classloader lock when another thread was in the middle of loading a
601 // superclass/superinterface for this class, and now
602 // this thread is also trying to load this class.
603 // To minimize surprises, the first thread that started to
604 // load a class should be the one to complete the loading
605 // with the classfile it initially expected.
606 // This logic has the current thread wait once it has done
607 // all the superclass/superinterface loading it can, until
608 // the original thread completes the class loading or fails
609 // If it completes we will use the resulting InstanceKlass
610 // which we will find below in the systemDictionary.
611 // We also get here for parallel bootstrap classloader
612 if (class_loader.is_null()) {
613 SystemDictionary_lock->wait();
614 } else {
615 double_lock_wait(lockObject, THREAD);
616 }
617 } else {
618 // If not in SD and not in PH, other thread's load must have failed
619 super_load_in_progress = false;
620 }
621 }
622 }
623 return NULL;
624 }
625
626 static void post_class_load_event(EventClassLoad* event,
627 const InstanceKlass* k,
628 const ClassLoaderData* init_cld) {
629 #if INCLUDE_TRACE
630 assert(event != NULL, "invariant");
631 assert(k != NULL, "invariant");
632 if (event->should_commit()) {
633 event->set_loadedClass(k);
634 event->set_definingClassLoader(k->class_loader_data());
635 event->set_initiatingClassLoader(init_cld);
636 event->commit();
637 }
638 #endif // INCLUDE_TRACE
639 }
640
641 static void class_define_event(InstanceKlass* k,
642 const ClassLoaderData* def_cld) {
643 #if INCLUDE_TRACE
644 EventClassDefine event;
645 if (event.should_commit()) {
646 event.set_definedClass(k);
647 event.set_definingClassLoader(def_cld);
648 event.commit();
649 }
650 #endif // INCLUDE_TRACE
651 }
652
653 // Be careful when modifying this code: once you have run
654 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
655 // you need to find_and_remove it before returning.
656 // So be careful to not exit with a CHECK_ macro betweeen these calls.
657 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
658 Handle class_loader,
659 Handle protection_domain,
660 TRAPS) {
661 assert(name != NULL && !FieldType::is_array(name) &&
662 !FieldType::is_obj(name), "invalid class name");
663
664 EventClassLoad class_load_start_event;
665
666 HandleMark hm(THREAD);
667
668 // Fix for 4474172; see evaluation for more details
669 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
670 ClassLoaderData* loader_data = register_loader(class_loader);
671 Dictionary* dictionary = loader_data->dictionary();
672 unsigned int d_hash = dictionary->compute_hash(name);
673
674 // Do lookup to see if class already exist and the protection domain
675 // has the right access
676 // This call uses find which checks protection domain already matches
677 // All subsequent calls use find_class, and set has_loaded_class so that
678 // before we return a result we call out to java to check for valid protection domain
679 // to allow returning the Klass* and add it to the pd_set if it is valid
680 {
681 Klass* probe = dictionary->find(d_hash, name, protection_domain);
682 if (probe != NULL) return probe;
683 }
684
685 // Non-bootstrap class loaders will call out to class loader and
686 // define via jvm/jni_DefineClass which will acquire the
687 // class loader object lock to protect against multiple threads
688 // defining the class in parallel by accident.
689 // This lock must be acquired here so the waiter will find
690 // any successful result in the SystemDictionary and not attempt
691 // the define.
692 // ParallelCapable Classloaders and the bootstrap classloader
693 // do not acquire lock here.
694 bool DoObjectLock = true;
695 if (is_parallelCapable(class_loader)) {
696 DoObjectLock = false;
697 }
698
699 unsigned int p_hash = placeholders()->compute_hash(name);
700 int p_index = placeholders()->hash_to_index(p_hash);
701
702 // Class is not in SystemDictionary so we have to do loading.
703 // Make sure we are synchronized on the class loader before we proceed
704 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
705 check_loader_lock_contention(lockObject, THREAD);
706 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
707
708 // Check again (after locking) if class already exist in SystemDictionary
709 bool class_has_been_loaded = false;
710 bool super_load_in_progress = false;
711 bool havesupername = false;
712 InstanceKlass* k = NULL;
713 PlaceholderEntry* placeholder;
714 Symbol* superclassname = NULL;
715
716 {
717 MutexLocker mu(SystemDictionary_lock, THREAD);
718 InstanceKlass* check = find_class(d_hash, name, dictionary);
719 if (check != NULL) {
720 // Klass is already loaded, so just return it
721 class_has_been_loaded = true;
722 k = check;
723 } else {
724 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
725 if (placeholder && placeholder->super_load_in_progress()) {
726 super_load_in_progress = true;
727 if (placeholder->havesupername() == true) {
728 superclassname = placeholder->supername();
729 havesupername = true;
730 }
731 }
732 }
733 }
734
735 // If the class is in the placeholder table, class loading is in progress
736 if (super_load_in_progress && havesupername==true) {
737 k = handle_parallel_super_load(name,
738 superclassname,
739 class_loader,
740 protection_domain,
741 lockObject, THREAD);
742 if (HAS_PENDING_EXCEPTION) {
743 return NULL;
744 }
745 if (k != NULL) {
746 class_has_been_loaded = true;
747 }
748 }
749
750 bool throw_circularity_error = false;
751 if (!class_has_been_loaded) {
752 bool load_instance_added = false;
753
754 // add placeholder entry to record loading instance class
755 // Five cases:
756 // All cases need to prevent modifying bootclasssearchpath
757 // in parallel with a classload of same classname
758 // Redefineclasses uses existence of the placeholder for the duration
759 // of the class load to prevent concurrent redefinition of not completely
760 // defined classes.
761 // case 1. traditional classloaders that rely on the classloader object lock
762 // - no other need for LOAD_INSTANCE
763 // case 2. traditional classloaders that break the classloader object lock
764 // as a deadlock workaround. Detection of this case requires that
765 // this check is done while holding the classloader object lock,
766 // and that lock is still held when calling classloader's loadClass.
767 // For these classloaders, we ensure that the first requestor
768 // completes the load and other requestors wait for completion.
769 // case 3. Bootstrap classloader - don't own objectLocker
770 // This classloader supports parallelism at the classloader level,
771 // but only allows a single load of a class/classloader pair.
772 // No performance benefit and no deadlock issues.
773 // case 4. parallelCapable user level classloaders - without objectLocker
774 // Allow parallel classloading of a class/classloader pair
775
776 {
777 MutexLocker mu(SystemDictionary_lock, THREAD);
778 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
779 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
780 if (oldprobe) {
781 // only need check_seen_thread once, not on each loop
782 // 6341374 java/lang/Instrument with -Xcomp
783 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
784 throw_circularity_error = true;
785 } else {
786 // case 1: traditional: should never see load_in_progress.
787 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
788
789 // case 3: bootstrap classloader: prevent futile classloading,
790 // wait on first requestor
791 if (class_loader.is_null()) {
792 SystemDictionary_lock->wait();
793 } else {
794 // case 2: traditional with broken classloader lock. wait on first
795 // requestor.
796 double_lock_wait(lockObject, THREAD);
797 }
798 // Check if classloading completed while we were waiting
799 InstanceKlass* check = find_class(d_hash, name, dictionary);
800 if (check != NULL) {
801 // Klass is already loaded, so just return it
802 k = check;
803 class_has_been_loaded = true;
804 }
805 // check if other thread failed to load and cleaned up
806 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
807 }
808 }
809 }
810 }
811 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
812 // case 4: parallelCapable: allow competing threads to try
813 // LOAD_INSTANCE in parallel
814
815 if (!throw_circularity_error && !class_has_been_loaded) {
816 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
817 load_instance_added = true;
818 // For class loaders that do not acquire the classloader object lock,
819 // if they did not catch another thread holding LOAD_INSTANCE,
820 // need a check analogous to the acquire ObjectLocker/find_class
821 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
822 // one final check if the load has already completed
823 // class loaders holding the ObjectLock shouldn't find the class here
824 InstanceKlass* check = find_class(d_hash, name, dictionary);
825 if (check != NULL) {
826 // Klass is already loaded, so return it after checking/adding protection domain
827 k = check;
828 class_has_been_loaded = true;
829 }
830 }
831 }
832
833 // must throw error outside of owning lock
834 if (throw_circularity_error) {
835 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
836 ResourceMark rm(THREAD);
837 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
838 }
839
840 if (!class_has_been_loaded) {
841
842 // Do actual loading
843 k = load_instance_class(name, class_loader, THREAD);
844
845 // If everything was OK (no exceptions, no null return value), and
846 // class_loader is NOT the defining loader, do a little more bookkeeping.
847 if (!HAS_PENDING_EXCEPTION && k != NULL &&
848 !oopDesc::equals(k->class_loader(), class_loader())) {
849
850 check_constraints(d_hash, k, class_loader, false, THREAD);
851
852 // Need to check for a PENDING_EXCEPTION again; check_constraints
853 // can throw and doesn't use the CHECK macro.
854 if (!HAS_PENDING_EXCEPTION) {
855 { // Grabbing the Compile_lock prevents systemDictionary updates
856 // during compilations.
857 MutexLocker mu(Compile_lock, THREAD);
858 update_dictionary(d_hash, p_index, p_hash,
859 k, class_loader, THREAD);
860 }
861
862 if (JvmtiExport::should_post_class_load()) {
863 Thread *thread = THREAD;
864 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
865 JvmtiExport::post_class_load((JavaThread *) thread, k);
866 }
867 }
868 }
869 } // load_instance_class
870
871 if (load_instance_added == true) {
872 // clean up placeholder entries for LOAD_INSTANCE success or error
873 // This brackets the SystemDictionary updates for both defining
874 // and initiating loaders
875 MutexLocker mu(SystemDictionary_lock, THREAD);
876 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
877 SystemDictionary_lock->notify_all();
878 }
879 }
880
881 if (HAS_PENDING_EXCEPTION || k == NULL) {
882 return NULL;
883 }
884
885 post_class_load_event(&class_load_start_event, k, loader_data);
886
887 #ifdef ASSERT
888 {
889 ClassLoaderData* loader_data = k->class_loader_data();
890 MutexLocker mu(SystemDictionary_lock, THREAD);
891 Klass* kk = find_class(name, loader_data);
892 assert(kk == k, "should be present in dictionary");
893 }
894 #endif
895
896 // return if the protection domain in NULL
897 if (protection_domain() == NULL) return k;
898
899 // Check the protection domain has the right access
900 if (dictionary->is_valid_protection_domain(d_hash, name,
901 protection_domain)) {
902 return k;
903 }
904
905 // Verify protection domain. If it fails an exception is thrown
906 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
907
908 return k;
909 }
910
911
912 // This routine does not lock the system dictionary.
913 //
914 // Since readers don't hold a lock, we must make sure that system
915 // dictionary entries are only removed at a safepoint (when only one
916 // thread is running), and are added to in a safe way (all links must
917 // be updated in an MT-safe manner).
918 //
919 // Callers should be aware that an entry could be added just after
920 // _dictionary->bucket(index) is read here, so the caller will not see
921 // the new entry.
922
923 Klass* SystemDictionary::find(Symbol* class_name,
924 Handle class_loader,
925 Handle protection_domain,
926 TRAPS) {
927
928 // The result of this call should be consistent with the result
929 // of the call to resolve_instance_class_or_null().
930 // See evaluation 6790209 and 4474172 for more details.
931 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
932 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
933
934 if (loader_data == NULL) {
935 // If the ClassLoaderData has not been setup,
936 // then the class loader has no entries in the dictionary.
937 return NULL;
938 }
939
940 Dictionary* dictionary = loader_data->dictionary();
941 unsigned int d_hash = dictionary->compute_hash(class_name);
942 return dictionary->find(d_hash, class_name,
943 protection_domain);
944 }
945
946
947 // Look for a loaded instance or array klass by name. Do not do any loading.
948 // return NULL in case of error.
949 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
950 Handle class_loader,
951 Handle protection_domain,
952 TRAPS) {
953 Klass* k = NULL;
954 assert(class_name != NULL, "class name must be non NULL");
955
956 if (FieldType::is_array(class_name)) {
957 // The name refers to an array. Parse the name.
958 // dimension and object_key in FieldArrayInfo are assigned as a
959 // side-effect of this call
960 FieldArrayInfo fd;
961 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
962 if (t != T_OBJECT) {
963 k = Universe::typeArrayKlassObj(t);
964 } else {
965 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
966 }
967 if (k != NULL) {
968 k = k->array_klass_or_null(fd.dimension());
969 }
970 } else {
971 k = find(class_name, class_loader, protection_domain, THREAD);
972 }
973 return k;
974 }
975
976 // Note: this method is much like resolve_from_stream, but
977 // does not publish the classes via the SystemDictionary.
978 // Handles unsafe_DefineAnonymousClass and redefineclasses
979 // RedefinedClasses do not add to the class hierarchy
980 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
981 Handle class_loader,
982 Handle protection_domain,
983 ClassFileStream* st,
984 const InstanceKlass* host_klass,
985 GrowableArray<Handle>* cp_patches,
986 TRAPS) {
987
988 EventClassLoad class_load_start_event;
989
990 ClassLoaderData* loader_data;
991 if (host_klass != NULL) {
992 // Create a new CLD for anonymous class, that uses the same class loader
993 // as the host_klass
994 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
995 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
996 } else {
997 loader_data = ClassLoaderData::class_loader_data(class_loader());
998 }
999
1000 assert(st != NULL, "invariant");
1001 assert(st->need_verify(), "invariant");
1002
1003 // Parse stream and create a klass.
1004 // Note that we do this even though this klass might
1005 // already be present in the SystemDictionary, otherwise we would not
1006 // throw potential ClassFormatErrors.
1007
1008 InstanceKlass* k = KlassFactory::create_from_stream(st,
1009 class_name,
1010 loader_data,
1011 protection_domain,
1012 host_klass,
1013 cp_patches,
1014 CHECK_NULL);
1015
1016 if (host_klass != NULL && k != NULL) {
1017 // Anonymous classes must update ClassLoaderData holder (was host_klass loader)
1018 // so that they can be unloaded when the mirror is no longer referenced.
1019 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1020
1021 {
1022 MutexLocker mu_r(Compile_lock, THREAD);
1023
1024 // Add to class hierarchy, initialize vtables, and do possible
1025 // deoptimizations.
1026 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1027
1028 // But, do not add to dictionary.
1029
1030 // compiled code dependencies need to be validated anyway
1031 notice_modification();
1032 }
1033
1034 // Rewrite and patch constant pool here.
1035 k->link_class(CHECK_NULL);
1036 if (cp_patches != NULL) {
1037 k->constants()->patch_resolved_references(cp_patches);
1038 }
1039
1040 // If it's anonymous, initialize it now, since nobody else will.
1041 k->eager_initialize(CHECK_NULL);
1042
1043 // notify jvmti
1044 if (JvmtiExport::should_post_class_load()) {
1045 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1046 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1047 }
1048
1049 post_class_load_event(&class_load_start_event, k, loader_data);
1050 }
1051 assert(host_klass != NULL || NULL == cp_patches,
1052 "cp_patches only found with host_klass");
1053
1054 return k;
1055 }
1056
1057 // Add a klass to the system from a stream (called by jni_DefineClass and
1058 // JVM_DefineClass).
1059 // Note: class_name can be NULL. In that case we do not know the name of
1060 // the class until we have parsed the stream.
1061
1062 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1063 Handle class_loader,
1064 Handle protection_domain,
1065 ClassFileStream* st,
1066 TRAPS) {
1067
1068 HandleMark hm(THREAD);
1069
1070 // Classloaders that support parallelism, e.g. bootstrap classloader,
1071 // do not acquire lock here
1072 bool DoObjectLock = true;
1073 if (is_parallelCapable(class_loader)) {
1074 DoObjectLock = false;
1075 }
1076
1077 ClassLoaderData* loader_data = register_loader(class_loader);
1078
1079 // Make sure we are synchronized on the class loader before we proceed
1080 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1081 check_loader_lock_contention(lockObject, THREAD);
1082 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1083
1084 assert(st != NULL, "invariant");
1085
1086 // Parse the stream and create a klass.
1087 // Note that we do this even though this klass might
1088 // already be present in the SystemDictionary, otherwise we would not
1089 // throw potential ClassFormatErrors.
1090 InstanceKlass* k = NULL;
1091
1092 #if INCLUDE_CDS
1093 if (!DumpSharedSpaces) {
1094 k = SystemDictionaryShared::lookup_from_stream(class_name,
1095 class_loader,
1096 protection_domain,
1097 st,
1098 CHECK_NULL);
1099 }
1100 #endif
1101
1102 if (k == NULL) {
1103 if (st->buffer() == NULL) {
1104 return NULL;
1105 }
1106 k = KlassFactory::create_from_stream(st,
1107 class_name,
1108 loader_data,
1109 protection_domain,
1110 NULL, // host_klass
1111 NULL, // cp_patches
1112 CHECK_NULL);
1113 }
1114
1115 assert(k != NULL, "no klass created");
1116 Symbol* h_name = k->name();
1117 assert(class_name == NULL || class_name == h_name, "name mismatch");
1118
1119 // Add class just loaded
1120 // If a class loader supports parallel classloading handle parallel define requests
1121 // find_or_define_instance_class may return a different InstanceKlass
1122 if (is_parallelCapable(class_loader)) {
1123 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1124 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1125 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1126 assert(defined_k != NULL, "Should have a klass if there's no exception");
1127 loader_data->add_to_deallocate_list(k);
1128 k = defined_k;
1129 }
1130 } else {
1131 define_instance_class(k, THREAD);
1132 }
1133
1134 // If defining the class throws an exception register 'k' for cleanup.
1135 if (HAS_PENDING_EXCEPTION) {
1136 assert(k != NULL, "Must have an instance klass here!");
1137 loader_data->add_to_deallocate_list(k);
1138 return NULL;
1139 }
1140
1141 // Make sure we have an entry in the SystemDictionary on success
1142 debug_only( {
1143 MutexLocker mu(SystemDictionary_lock, THREAD);
1144
1145 Klass* check = find_class(h_name, k->class_loader_data());
1146 assert(check == k, "should be present in the dictionary");
1147 } );
1148
1149 return k;
1150 }
1151
1152 #if INCLUDE_CDS
1153 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1154 int number_of_entries) {
1155 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1156 "bad shared dictionary size.");
1157 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1158 _shared_dictionary_size, t, number_of_entries);
1159 }
1160
1161
1162 // If there is a shared dictionary, then find the entry for the
1163 // given shared system class, if any.
1164
1165 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1166 if (shared_dictionary() != NULL) {
1167 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1168 int d_index = shared_dictionary()->hash_to_index(d_hash);
1169
1170 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1171 } else {
1172 return NULL;
1173 }
1174 }
1175
1176
1177 // Load a class from the shared spaces (found through the shared system
1178 // dictionary). Force the superclass and all interfaces to be loaded.
1179 // Update the class definition to include sibling classes and no
1180 // subclasses (yet). [Classes in the shared space are not part of the
1181 // object hierarchy until loaded.]
1182
1183 InstanceKlass* SystemDictionary::load_shared_class(
1184 Symbol* class_name, Handle class_loader, TRAPS) {
1185 InstanceKlass* ik = find_shared_class(class_name);
1186 // Make sure we only return the boot class for the NULL classloader.
1187 if (ik != NULL &&
1188 ik->is_shared_boot_class() && class_loader.is_null()) {
1189 Handle protection_domain;
1190 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1191 }
1192 return NULL;
1193 }
1194
1195 // Check if a shared class can be loaded by the specific classloader:
1196 //
1197 // NULL classloader:
1198 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1199 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1200 // be defined in an unnamed module.
1201 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1202 InstanceKlass* ik,
1203 Handle class_loader, TRAPS) {
1204 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1205 "Cannot use sharing if java.base is patched");
1206 ResourceMark rm;
1207 int path_index = ik->shared_classpath_index();
1208 ClassLoaderData* loader_data = class_loader_data(class_loader);
1209 if (path_index < 0) {
1210 // path_index < 0 indicates that the class is intended for a custom loader
1211 // and should not be loaded by boot/platform/app loaders
1212 if (loader_data->is_builtin_class_loader_data()) {
1213 return false;
1214 } else {
1215 return true;
1216 }
1217 }
1218 SharedClassPathEntry* ent =
1219 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1220 if (!Universe::is_module_initialized()) {
1221 assert(ent != NULL && ent->is_modules_image(),
1222 "Loading non-bootstrap classes before the module system is initialized");
1223 assert(class_loader.is_null(), "sanity");
1224 return true;
1225 }
1226 // Get the pkg_entry from the classloader
1227 TempNewSymbol pkg_name = NULL;
1228 PackageEntry* pkg_entry = NULL;
1229 ModuleEntry* mod_entry = NULL;
1230 const char* pkg_string = NULL;
1231 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1232 if (pkg_name != NULL) {
1233 pkg_string = pkg_name->as_C_string();
1234 if (loader_data != NULL) {
1235 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1236 }
1237 if (pkg_entry != NULL) {
1238 mod_entry = pkg_entry->module();
1239 }
1240 }
1241
1242 // If the archived class is from a module that has been patched at runtime,
1243 // the class cannot be loaded from the archive.
1244 if (mod_entry != NULL && mod_entry->is_patched()) {
1245 return false;
1246 }
1247
1248 if (class_loader.is_null()) {
1249 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1250 // The NULL classloader can load archived class originated from the
1251 // "modules" jimage and the -Xbootclasspath/a. For class from the
1252 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1253 // by the NULL classloader.
1254 if (mod_entry != NULL) {
1255 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1256 // ModuleEntry's location agrees with the archived class' origination.
1257 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1258 return true; // Module class from the "module" jimage
1259 }
1260 }
1261
1262 // If the archived class is not from the "module" jimage, the class can be
1263 // loaded by the NULL classloader if
1264 //
1265 // 1. the class is from the unamed package
1266 // 2. or, the class is not from a module defined in the NULL classloader
1267 // 3. or, the class is from an unamed module
1268 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1269 // the class is from the -Xbootclasspath/a
1270 if (pkg_string == NULL ||
1271 pkg_entry == NULL ||
1272 pkg_entry->in_unnamed_module()) {
1273 assert(mod_entry == NULL ||
1274 mod_entry == loader_data->unnamed_module(),
1275 "the unnamed module is not defined in the classloader");
1276 return true;
1277 }
1278 }
1279 return false;
1280 } else {
1281 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1282 ik, class_loader, pkg_string, pkg_name,
1283 pkg_entry, mod_entry, CHECK_(false));
1284 return res;
1285 }
1286 }
1287
1288 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1289 Handle class_loader,
1290 Handle protection_domain, TRAPS) {
1291
1292 if (ik != NULL) {
1293 Symbol* class_name = ik->name();
1294
1295 bool visible = is_shared_class_visible(
1296 class_name, ik, class_loader, CHECK_NULL);
1297 if (!visible) {
1298 return NULL;
1299 }
1300
1301 // Resolve the superclass and interfaces. They must be the same
1302 // as in dump time, because the layout of <ik> depends on
1303 // the specific layout of ik->super() and ik->local_interfaces().
1304 //
1305 // If unexpected superclass or interfaces are found, we cannot
1306 // load <ik> from the shared archive.
1307
1308 if (ik->super() != NULL) {
1309 Symbol* cn = ik->super()->name();
1310 Klass *s = resolve_super_or_fail(class_name, cn,
1311 class_loader, protection_domain, true, CHECK_NULL);
1312 if (s != ik->super()) {
1313 // The dynamically resolved super class is not the same as the one we used during dump time,
1314 // so we cannot use ik.
1315 return NULL;
1316 } else {
1317 assert(s->is_shared(), "must be");
1318 }
1319 }
1320
1321 Array<Klass*>* interfaces = ik->local_interfaces();
1322 int num_interfaces = interfaces->length();
1323 for (int index = 0; index < num_interfaces; index++) {
1324 Klass* k = interfaces->at(index);
1325 Symbol* name = k->name();
1326 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1327 if (k != i) {
1328 // The dynamically resolved interface class is not the same as the one we used during dump time,
1329 // so we cannot use ik.
1330 return NULL;
1331 } else {
1332 assert(i->is_shared(), "must be");
1333 }
1334 }
1335
1336 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1337 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1338 if (new_ik != NULL) {
1339 // The class is changed by CFLH. Return the new class. The shared class is
1340 // not used.
1341 return new_ik;
1342 }
1343
1344 // Adjust methods to recover missing data. They need addresses for
1345 // interpreter entry points and their default native method address
1346 // must be reset.
1347
1348 // Updating methods must be done under a lock so multiple
1349 // threads don't update these in parallel
1350 //
1351 // Shared classes are all currently loaded by either the bootstrap or
1352 // internal parallel class loaders, so this will never cause a deadlock
1353 // on a custom class loader lock.
1354
1355 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1356 {
1357 HandleMark hm(THREAD);
1358 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1359 check_loader_lock_contention(lockObject, THREAD);
1360 ObjectLocker ol(lockObject, THREAD, true);
1361 // prohibited package check assumes all classes loaded from archive call
1362 // restore_unshareable_info which calls ik->set_package()
1363 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1364 }
1365
1366 ik->print_class_load_logging(loader_data, NULL, NULL);
1367
1368 // For boot loader, ensure that GetSystemPackage knows that a class in this
1369 // package was loaded.
1370 if (class_loader.is_null()) {
1371 int path_index = ik->shared_classpath_index();
1372 ResourceMark rm;
1373 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1374 }
1375
1376 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1377 // Only dump the classes that can be stored into CDS archive
1378 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1379 ResourceMark rm(THREAD);
1380 classlist_file->print_cr("%s", ik->name()->as_C_string());
1381 classlist_file->flush();
1382 }
1383 }
1384
1385 // notify a class loaded from shared object
1386 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1387 }
1388
1389 ik->set_has_passed_fingerprint_check(false);
1390 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1391 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1392 uint64_t cds_fp = ik->get_stored_fingerprint();
1393 if (aot_fp != 0 && aot_fp == cds_fp) {
1394 // This class matches with a class saved in an AOT library
1395 ik->set_has_passed_fingerprint_check(true);
1396 } else {
1397 ResourceMark rm;
1398 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1399 }
1400 }
1401 return ik;
1402 }
1403
1404 void SystemDictionary::clear_invoke_method_table() {
1405 SymbolPropertyEntry* spe = NULL;
1406 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1407 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1408 while (p != NULL) {
1409 spe = p;
1410 p = p->next();
1411 _invoke_method_table->free_entry(spe);
1412 }
1413 }
1414 }
1415 #endif // INCLUDE_CDS
1416
1417 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1418
1419 if (class_loader.is_null()) {
1420 ResourceMark rm;
1421 PackageEntry* pkg_entry = NULL;
1422 bool search_only_bootloader_append = false;
1423 ClassLoaderData *loader_data = class_loader_data(class_loader);
1424
1425 // Find the package in the boot loader's package entry table.
1426 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1427 if (pkg_name != NULL) {
1428 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1429 }
1430
1431 // Prior to attempting to load the class, enforce the boot loader's
1432 // visibility boundaries.
1433 if (!Universe::is_module_initialized()) {
1434 // During bootstrapping, prior to module initialization, any
1435 // class attempting to be loaded must be checked against the
1436 // java.base packages in the boot loader's PackageEntryTable.
1437 // No class outside of java.base is allowed to be loaded during
1438 // this bootstrapping window.
1439 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1440 // Class is either in the unnamed package or in
1441 // a named package within the unnamed module. Either
1442 // case is outside of java.base, do not attempt to
1443 // load the class post java.base definition. If
1444 // java.base has not been defined, let the class load
1445 // and its package will be checked later by
1446 // ModuleEntryTable::verify_javabase_packages.
1447 if (ModuleEntryTable::javabase_defined()) {
1448 return NULL;
1449 }
1450 } else {
1451 // Check that the class' package is defined within java.base.
1452 ModuleEntry* mod_entry = pkg_entry->module();
1453 Symbol* mod_entry_name = mod_entry->name();
1454 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1455 return NULL;
1456 }
1457 }
1458 } else {
1459 // After the module system has been initialized, check if the class'
1460 // package is in a module defined to the boot loader.
1461 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1462 // Class is either in the unnamed package, in a named package
1463 // within a module not defined to the boot loader or in a
1464 // a named package within the unnamed module. In all cases,
1465 // limit visibility to search for the class only in the boot
1466 // loader's append path.
1467 search_only_bootloader_append = true;
1468 }
1469 }
1470
1471 // Prior to bootstrapping's module initialization, never load a class outside
1472 // of the boot loader's module path
1473 assert(Universe::is_module_initialized() ||
1474 !search_only_bootloader_append,
1475 "Attempt to load a class outside of boot loader's module path");
1476
1477 // Search the shared system dictionary for classes preloaded into the
1478 // shared spaces.
1479 InstanceKlass* k = NULL;
1480 {
1481 #if INCLUDE_CDS
1482 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1483 k = load_shared_class(class_name, class_loader, THREAD);
1484 #endif
1485 }
1486
1487 if (k == NULL) {
1488 // Use VM class loader
1489 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1490 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1491 }
1492
1493 // find_or_define_instance_class may return a different InstanceKlass
1494 if (k != NULL) {
1495 InstanceKlass* defined_k =
1496 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1497 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1498 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1499 assert(defined_k != NULL, "Should have a klass if there's no exception");
1500 loader_data->add_to_deallocate_list(k);
1501 k = defined_k;
1502 } else if (HAS_PENDING_EXCEPTION) {
1503 loader_data->add_to_deallocate_list(k);
1504 return NULL;
1505 }
1506 }
1507 return k;
1508 } else {
1509 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1510 ResourceMark rm(THREAD);
1511
1512 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1513 JavaThread* jt = (JavaThread*) THREAD;
1514
1515 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1516 ClassLoader::perf_app_classload_selftime(),
1517 ClassLoader::perf_app_classload_count(),
1518 jt->get_thread_stat()->perf_recursion_counts_addr(),
1519 jt->get_thread_stat()->perf_timers_addr(),
1520 PerfClassTraceTime::CLASS_LOAD);
1521
1522 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1523 // Translate to external class name format, i.e., convert '/' chars to '.'
1524 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1525
1526 JavaValue result(T_OBJECT);
1527
1528 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1529
1530 // Call public unsynchronized loadClass(String) directly for all class loaders.
1531 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1532 // acquire a class-name based lock rather than the class loader object lock.
1533 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1534 JavaCalls::call_virtual(&result,
1535 class_loader,
1536 spec_klass,
1537 vmSymbols::loadClass_name(),
1538 vmSymbols::string_class_signature(),
1539 string,
1540 CHECK_NULL);
1541
1542 assert(result.get_type() == T_OBJECT, "just checking");
1543 oop obj = (oop) result.get_jobject();
1544
1545 // Primitive classes return null since forName() can not be
1546 // used to obtain any of the Class objects representing primitives or void
1547 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1548 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1549 // For user defined Java class loaders, check that the name returned is
1550 // the same as that requested. This check is done for the bootstrap
1551 // loader when parsing the class file.
1552 if (class_name == k->name()) {
1553 return k;
1554 }
1555 }
1556 // Class is not found or has the wrong name, return NULL
1557 return NULL;
1558 }
1559 }
1560
1561 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1562
1563 HandleMark hm(THREAD);
1564 ClassLoaderData* loader_data = k->class_loader_data();
1565 Handle class_loader_h(THREAD, loader_data->class_loader());
1566
1567 // for bootstrap and other parallel classloaders don't acquire lock,
1568 // use placeholder token
1569 // If a parallelCapable class loader calls define_instance_class instead of
1570 // find_or_define_instance_class to get here, we have a timing
1571 // hole with systemDictionary updates and check_constraints
1572 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1573 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1574 compute_loader_lock_object(class_loader_h, THREAD)),
1575 "define called without lock");
1576 }
1577
1578 // Check class-loading constraints. Throw exception if violation is detected.
1579 // Grabs and releases SystemDictionary_lock
1580 // The check_constraints/find_class call and update_dictionary sequence
1581 // must be "atomic" for a specific class/classloader pair so we never
1582 // define two different instanceKlasses for that class/classloader pair.
1583 // Existing classloaders will call define_instance_class with the
1584 // classloader lock held
1585 // Parallel classloaders will call find_or_define_instance_class
1586 // which will require a token to perform the define class
1587 Symbol* name_h = k->name();
1588 Dictionary* dictionary = loader_data->dictionary();
1589 unsigned int d_hash = dictionary->compute_hash(name_h);
1590 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1591
1592 // Register class just loaded with class loader (placed in Vector)
1593 // Note we do this before updating the dictionary, as this can
1594 // fail with an OutOfMemoryError (if it does, we will *not* put this
1595 // class in the dictionary and will not update the class hierarchy).
1596 // JVMTI FollowReferences needs to find the classes this way.
1597 if (k->class_loader() != NULL) {
1598 methodHandle m(THREAD, Universe::loader_addClass_method());
1599 JavaValue result(T_VOID);
1600 JavaCallArguments args(class_loader_h);
1601 args.push_oop(Handle(THREAD, k->java_mirror()));
1602 JavaCalls::call(&result, m, &args, CHECK);
1603 }
1604
1605 // Add the new class. We need recompile lock during update of CHA.
1606 {
1607 unsigned int p_hash = placeholders()->compute_hash(name_h);
1608 int p_index = placeholders()->hash_to_index(p_hash);
1609
1610 MutexLocker mu_r(Compile_lock, THREAD);
1611
1612 // Add to class hierarchy, initialize vtables, and do possible
1613 // deoptimizations.
1614 add_to_hierarchy(k, CHECK); // No exception, but can block
1615
1616 // Add to systemDictionary - so other classes can see it.
1617 // Grabs and releases SystemDictionary_lock
1618 update_dictionary(d_hash, p_index, p_hash,
1619 k, class_loader_h, THREAD);
1620 }
1621 k->eager_initialize(THREAD);
1622
1623 // notify jvmti
1624 if (JvmtiExport::should_post_class_load()) {
1625 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1626 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1627
1628 }
1629 class_define_event(k, loader_data);
1630 }
1631
1632 // Support parallel classloading
1633 // All parallel class loaders, including bootstrap classloader
1634 // lock a placeholder entry for this class/class_loader pair
1635 // to allow parallel defines of different classes for this class loader
1636 // With AllowParallelDefine flag==true, in case they do not synchronize around
1637 // FindLoadedClass/DefineClass, calls, we check for parallel
1638 // loading for them, wait if a defineClass is in progress
1639 // and return the initial requestor's results
1640 // This flag does not apply to the bootstrap classloader.
1641 // With AllowParallelDefine flag==false, call through to define_instance_class
1642 // which will throw LinkageError: duplicate class definition.
1643 // False is the requested default.
1644 // For better performance, the class loaders should synchronize
1645 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1646 // potentially waste time reading and parsing the bytestream.
1647 // Note: VM callers should ensure consistency of k/class_name,class_loader
1648 // Be careful when modifying this code: once you have run
1649 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1650 // you need to find_and_remove it before returning.
1651 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1652 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1653 InstanceKlass* k, TRAPS) {
1654
1655 Symbol* name_h = k->name(); // passed in class_name may be null
1656 ClassLoaderData* loader_data = class_loader_data(class_loader);
1657 Dictionary* dictionary = loader_data->dictionary();
1658
1659 unsigned int d_hash = dictionary->compute_hash(name_h);
1660
1661 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1662 unsigned int p_hash = placeholders()->compute_hash(name_h);
1663 int p_index = placeholders()->hash_to_index(p_hash);
1664 PlaceholderEntry* probe;
1665
1666 {
1667 MutexLocker mu(SystemDictionary_lock, THREAD);
1668 // First check if class already defined
1669 if (is_parallelDefine(class_loader)) {
1670 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1671 if (check != NULL) {
1672 return check;
1673 }
1674 }
1675
1676 // Acquire define token for this class/classloader
1677 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1678 // Wait if another thread defining in parallel
1679 // All threads wait - even those that will throw duplicate class: otherwise
1680 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1681 // if other thread has not finished updating dictionary
1682 while (probe->definer() != NULL) {
1683 SystemDictionary_lock->wait();
1684 }
1685 // Only special cases allow parallel defines and can use other thread's results
1686 // Other cases fall through, and may run into duplicate defines
1687 // caught by finding an entry in the SystemDictionary
1688 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1689 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1690 SystemDictionary_lock->notify_all();
1691 #ifdef ASSERT
1692 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1693 assert(check != NULL, "definer missed recording success");
1694 #endif
1695 return probe->instance_klass();
1696 } else {
1697 // This thread will define the class (even if earlier thread tried and had an error)
1698 probe->set_definer(THREAD);
1699 }
1700 }
1701
1702 define_instance_class(k, THREAD);
1703
1704 Handle linkage_exception = Handle(); // null handle
1705
1706 // definer must notify any waiting threads
1707 {
1708 MutexLocker mu(SystemDictionary_lock, THREAD);
1709 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1710 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1711 if (probe != NULL) {
1712 if (HAS_PENDING_EXCEPTION) {
1713 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1714 CLEAR_PENDING_EXCEPTION;
1715 } else {
1716 probe->set_instance_klass(k);
1717 }
1718 probe->set_definer(NULL);
1719 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1720 SystemDictionary_lock->notify_all();
1721 }
1722 }
1723
1724 // Can't throw exception while holding lock due to rank ordering
1725 if (linkage_exception() != NULL) {
1726 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1727 }
1728
1729 return k;
1730 }
1731
1732 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1733 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1734 if (class_loader.is_null()) {
1735 return Handle(THREAD, _system_loader_lock_obj);
1736 } else {
1737 return class_loader;
1738 }
1739 }
1740
1741 // This method is added to check how often we have to wait to grab loader
1742 // lock. The results are being recorded in the performance counters defined in
1743 // ClassLoader::_sync_systemLoaderLockContentionRate and
1744 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1745 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1746 if (!UsePerfData) {
1747 return;
1748 }
1749
1750 assert(!loader_lock.is_null(), "NULL lock object");
1751
1752 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1753 == ObjectSynchronizer::owner_other) {
1754 // contention will likely happen, so increment the corresponding
1755 // contention counter.
1756 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1757 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1758 } else {
1759 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1760 }
1761 }
1762 }
1763
1764 // ----------------------------------------------------------------------------
1765 // Lookup
1766
1767 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1768 Symbol* class_name,
1769 Dictionary* dictionary) {
1770 assert_locked_or_safepoint(SystemDictionary_lock);
1771 int index = dictionary->hash_to_index(hash);
1772 return dictionary->find_class(index, hash, class_name);
1773 }
1774
1775
1776 // Basic find on classes in the midst of being loaded
1777 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1778 ClassLoaderData* loader_data) {
1779 assert_locked_or_safepoint(SystemDictionary_lock);
1780 unsigned int p_hash = placeholders()->compute_hash(class_name);
1781 int p_index = placeholders()->hash_to_index(p_hash);
1782 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1783 }
1784
1785
1786 // Used for assertions and verification only
1787 // Precalculating the hash and index is an optimization because there are many lookups
1788 // before adding the class.
1789 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1790 assert_locked_or_safepoint(SystemDictionary_lock);
1791 #ifndef ASSERT
1792 guarantee(VerifyBeforeGC ||
1793 VerifyDuringGC ||
1794 VerifyBeforeExit ||
1795 VerifyDuringStartup ||
1796 VerifyAfterGC, "too expensive");
1797 #endif
1798
1799 Dictionary* dictionary = loader_data->dictionary();
1800 unsigned int d_hash = dictionary->compute_hash(class_name);
1801 return find_class(d_hash, class_name, dictionary);
1802 }
1803
1804
1805 // ----------------------------------------------------------------------------
1806 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1807 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1808 // before a new class is used.
1809
1810 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1811 assert(k != NULL, "just checking");
1812 assert_locked_or_safepoint(Compile_lock);
1813
1814 // Link into hierachy. Make sure the vtables are initialized before linking into
1815 k->append_to_sibling_list(); // add to superklass/sibling list
1816 k->process_interfaces(THREAD); // handle all "implements" declarations
1817 k->set_init_state(InstanceKlass::loaded);
1818 // Now flush all code that depended on old class hierarchy.
1819 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1820 // Also, first reinitialize vtable because it may have gotten out of synch
1821 // while the new class wasn't connected to the class hierarchy.
1822 CodeCache::flush_dependents_on(k);
1823 }
1824
1825 // ----------------------------------------------------------------------------
1826 // GC support
1827
1828 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1829 roots_oops_do(blk, NULL);
1830 }
1831
1832
1833 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1834 // Note: anonymous classes are not in the SD.
1835 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1836 GCTimer* gc_timer,
1837 bool do_cleaning) {
1838
1839 {
1840 GCTraceTime(Debug, gc, phases) t("SystemDictionary WeakHandle cleaning", gc_timer);
1841 vm_weak_oop_storage()->weak_oops_do(is_alive, &do_nothing_cl);
1842 }
1843
1844 bool unloading_occurred;
1845 {
1846 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1847
1848 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1849 unloading_occurred = ClassLoaderDataGraph::do_unloading(do_cleaning);
1850 }
1851
1852 if (unloading_occurred) {
1853 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1854 constraints()->purge_loader_constraints();
1855 resolution_errors()->purge_resolution_errors();
1856 }
1857
1858 {
1859 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1860 // Oops referenced by the protection domain cache table may get unreachable independently
1861 // of the class loader (eg. cached protection domain oops). So we need to
1862 // explicitly unlink them here.
1863 _pd_cache_table->unlink();
1864 }
1865
1866 if (do_cleaning) {
1867 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1868 ResolvedMethodTable::unlink();
1869 }
1870
1871 return unloading_occurred;
1872 }
1873
1874 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1875 strong->do_oop(&_java_system_loader);
1876 strong->do_oop(&_java_platform_loader);
1877 strong->do_oop(&_system_loader_lock_obj);
1878 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1879
1880 // Do strong roots marking if the closures are the same.
1881 if (strong == weak || !ClassUnloading) {
1882 // Only the protection domain oops contain references into the heap. Iterate
1883 // over all of them.
1884 vm_weak_oop_storage()->oops_do(strong);
1885 } else {
1886 if (weak != NULL) {
1887 vm_weak_oop_storage()->oops_do(weak);
1888 }
1889 }
1890
1891 // Visit extra methods
1892 invoke_method_table()->oops_do(strong);
1893 }
1894
1895 void SystemDictionary::oops_do(OopClosure* f) {
1896 f->do_oop(&_java_system_loader);
1897 f->do_oop(&_java_platform_loader);
1898 f->do_oop(&_system_loader_lock_obj);
1899 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1900
1901 // Visit extra methods
1902 invoke_method_table()->oops_do(f);
1903
1904 vm_weak_oop_storage()->oops_do(f);
1905 }
1906
1907 // CDS: scan and relocate all classes in the system dictionary.
1908 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1909 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1910 }
1911
1912 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1913 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1914 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1915 it->push(well_known_klass_addr((WKID)id));
1916 }
1917 }
1918
1919 void SystemDictionary::methods_do(void f(Method*)) {
1920 // Walk methods in loaded classes
1921 ClassLoaderDataGraph::methods_do(f);
1922 // Walk method handle intrinsics
1923 invoke_method_table()->methods_do(f);
1924 }
1925
1926 class RemoveClassesClosure : public CLDClosure {
1927 public:
1928 void do_cld(ClassLoaderData* cld) {
1929 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1930 cld->dictionary()->remove_classes_in_error_state();
1931 }
1932 }
1933 };
1934
1935 void SystemDictionary::remove_classes_in_error_state() {
1936 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1937 RemoveClassesClosure rcc;
1938 ClassLoaderDataGraph::cld_do(&rcc);
1939 }
1940
1941 // ----------------------------------------------------------------------------
1942 // Lazily load klasses
1943
1944 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1945 // if multiple threads calling this function, only one thread will load
1946 // the class. The other threads will find the loaded version once the
1947 // class is loaded.
1948 Klass* aos = _abstract_ownable_synchronizer_klass;
1949 if (aos == NULL) {
1950 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1951 // Force a fence to prevent any read before the write completes
1952 OrderAccess::fence();
1953 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1954 }
1955 }
1956
1957 // ----------------------------------------------------------------------------
1958 // Initialization
1959
1960 void SystemDictionary::initialize(TRAPS) {
1961 // Allocate arrays
1962 _placeholders = new PlaceholderTable(_placeholder_table_size);
1963 _number_of_modifications = 0;
1964 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1965 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1966 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1967 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1968
1969 // Allocate private object used as system class loader lock
1970 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1971 // Initialize basic classes
1972 initialize_preloaded_classes(CHECK);
1973 }
1974
1975 // Compact table of directions on the initialization of klasses:
1976 static const short wk_init_info[] = {
1977 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1978 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1979 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1980 | (int)SystemDictionary::option ),
1981 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1982 #undef WK_KLASS_INIT_INFO
1983 0
1984 };
1985
1986 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1987 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1988 int info = wk_init_info[id - FIRST_WKID];
1989 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1990 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1991 InstanceKlass** klassp = &_well_known_klasses[id];
1992
1993 bool must_load;
1994 #if INCLUDE_JVMCI
1995 if (EnableJVMCI) {
1996 // If JVMCI is enabled we require its classes to be found.
1997 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
1998 } else
1999 #endif
2000 {
2001 must_load = (init_opt < SystemDictionary::Opt);
2002 }
2003
2004 if ((*klassp) == NULL) {
2005 Klass* k;
2006 if (must_load) {
2007 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2008 } else {
2009 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2010 }
2011 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2012 }
2013 return ((*klassp) != NULL);
2014 }
2015
2016 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2017 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2018 for (int id = (int)start_id; id < (int)limit_id; id++) {
2019 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2020 int info = wk_init_info[id - FIRST_WKID];
2021 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2022 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2023
2024 initialize_wk_klass((WKID)id, opt, CHECK);
2025 }
2026
2027 // move the starting value forward to the limit:
2028 start_id = limit_id;
2029 }
2030
2031 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2032 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2033
2034 // Create the ModuleEntry for java.base. This call needs to be done here,
2035 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2036 ClassLoader::classLoader_init2(CHECK);
2037
2038 // Preload commonly used klasses
2039 WKID scan = FIRST_WKID;
2040 // first do Object, then String, Class
2041 #if INCLUDE_CDS
2042 if (UseSharedSpaces) {
2043 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2044 // Initialize the constant pool for the Object_class
2045 Object_klass()->constants()->restore_unshareable_info(CHECK);
2046 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2047 } else
2048 #endif
2049 {
2050 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2051 }
2052
2053 // Calculate offsets for String and Class classes since they are loaded and
2054 // can be used after this point.
2055 java_lang_String::compute_offsets();
2056 java_lang_Class::compute_offsets();
2057
2058 // Fixup mirrors for classes loaded before java.lang.Class.
2059 // These calls iterate over the objects currently in the perm gen
2060 // so calling them at this point is matters (not before when there
2061 // are fewer objects and not later after there are more objects
2062 // in the perm gen.
2063 Universe::initialize_basic_type_mirrors(CHECK);
2064 Universe::fixup_mirrors(CHECK);
2065
2066 // do a bunch more:
2067 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2068
2069 // Preload ref klasses and set reference types
2070 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2071 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2072
2073 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2074 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2075 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2076 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2077 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2078
2079 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
2080
2081 // JSR 292 classes
2082 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2083 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2084 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2085 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2086 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2087
2088 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2089 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2090 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2091 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2092 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2093 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2094 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2095 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2096 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2097 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2098
2099 { // Compute whether we should use checkPackageAccess or NOT
2100 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2101 _has_checkPackageAccess = (method != NULL);
2102 }
2103 }
2104
2105 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2106 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2107 BasicType SystemDictionary::box_klass_type(Klass* k) {
2108 assert(k != NULL, "");
2109 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2110 if (_box_klasses[i] == k)
2111 return (BasicType)i;
2112 }
2113 return T_OBJECT;
2114 }
2115
2116 // Constraints on class loaders. The details of the algorithm can be
2117 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2118 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2119 // that the dictionary needs to maintain a set of contraints that
2120 // must be satisfied by all classes in the dictionary.
2121 // if defining is true, then LinkageError if already in dictionary
2122 // if initiating loader, then ok if InstanceKlass matches existing entry
2123
2124 void SystemDictionary::check_constraints(unsigned int d_hash,
2125 InstanceKlass* k,
2126 Handle class_loader,
2127 bool defining,
2128 TRAPS) {
2129 ResourceMark rm(THREAD);
2130 stringStream ss;
2131 bool throwException = false;
2132
2133 const char *linkage_error1 = NULL;
2134 const char *linkage_error2 = NULL;
2135 const char *linkage_error3 = "";
2136 // Remember the loader of the similar class that is already loaded.
2137 const char *existing_klass_loader_name = "";
2138
2139 {
2140 Symbol* name = k->name();
2141 ClassLoaderData *loader_data = class_loader_data(class_loader);
2142
2143 MutexLocker mu(SystemDictionary_lock, THREAD);
2144
2145 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2146 if (check != NULL) {
2147 // If different InstanceKlass - duplicate class definition,
2148 // else - ok, class loaded by a different thread in parallel.
2149 // We should only have found it if it was done loading and ok to use.
2150 // The dictionary only holds instance classes, placeholders
2151 // also hold array classes.
2152
2153 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2154 if ((defining == true) || (k != check)) {
2155 throwException = true;
2156 ss.print("loader %s", java_lang_ClassLoader::describe_external(class_loader()));
2157 ss.print(" attempted duplicate %s definition for %s.",
2158 k->external_kind(), k->external_name());
2159 } else {
2160 return;
2161 }
2162 }
2163
2164 #ifdef ASSERT
2165 Symbol* ph_check = find_placeholder(name, loader_data);
2166 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2167 #endif
2168
2169 if (throwException == false) {
2170 if (constraints()->check_or_update(k, class_loader, name) == false) {
2171 throwException = true;
2172 ss.print("loader constraint violation: loader %s",
2173 java_lang_ClassLoader::describe_external(class_loader()));
2174 ss.print(" wants to load %s %s.",
2175 k->external_kind(), k->external_name());
2176 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2177 if (existing_klass->class_loader() != class_loader()) {
2178 ss.print(" A different %s with the same name was previously loaded by %s.",
2179 existing_klass->external_kind(),
2180 java_lang_ClassLoader::describe_external(existing_klass->class_loader()));
2181 }
2182 }
2183 }
2184 }
2185
2186 // Throw error now if needed (cannot throw while holding
2187 // SystemDictionary_lock because of rank ordering)
2188 if (throwException == true) {
2189 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2190 }
2191 }
2192
2193 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2194 // have been called.
2195 void SystemDictionary::update_dictionary(unsigned int d_hash,
2196 int p_index, unsigned int p_hash,
2197 InstanceKlass* k,
2198 Handle class_loader,
2199 TRAPS) {
2200 // Compile_lock prevents systemDictionary updates during compilations
2201 assert_locked_or_safepoint(Compile_lock);
2202 Symbol* name = k->name();
2203 ClassLoaderData *loader_data = class_loader_data(class_loader);
2204
2205 {
2206 MutexLocker mu1(SystemDictionary_lock, THREAD);
2207
2208 // See whether biased locking is enabled and if so set it for this
2209 // klass.
2210 // Note that this must be done past the last potential blocking
2211 // point / safepoint. We enable biased locking lazily using a
2212 // VM_Operation to iterate the SystemDictionary and installing the
2213 // biasable mark word into each InstanceKlass's prototype header.
2214 // To avoid race conditions where we accidentally miss enabling the
2215 // optimization for one class in the process of being added to the
2216 // dictionary, we must not safepoint after the test of
2217 // BiasedLocking::enabled().
2218 if (UseBiasedLocking && BiasedLocking::enabled()) {
2219 // Set biased locking bit for all loaded classes; it will be
2220 // cleared if revocation occurs too often for this type
2221 // NOTE that we must only do this when the class is initally
2222 // defined, not each time it is referenced from a new class loader
2223 if (oopDesc::equals(k->class_loader(), class_loader())) {
2224 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2225 }
2226 }
2227
2228 // Make a new dictionary entry.
2229 Dictionary* dictionary = loader_data->dictionary();
2230 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2231 if (sd_check == NULL) {
2232 dictionary->add_klass(d_hash, name, k);
2233 notice_modification();
2234 }
2235 #ifdef ASSERT
2236 sd_check = find_class(d_hash, name, dictionary);
2237 assert (sd_check != NULL, "should have entry in dictionary");
2238 // Note: there may be a placeholder entry: for circularity testing
2239 // or for parallel defines
2240 #endif
2241 SystemDictionary_lock->notify_all();
2242 }
2243 }
2244
2245
2246 // Try to find a class name using the loader constraints. The
2247 // loader constraints might know about a class that isn't fully loaded
2248 // yet and these will be ignored.
2249 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2250 Symbol* class_name, Handle class_loader, TRAPS) {
2251
2252 // First see if it has been loaded directly.
2253 // Force the protection domain to be null. (This removes protection checks.)
2254 Handle no_protection_domain;
2255 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2256 no_protection_domain, CHECK_NULL);
2257 if (klass != NULL)
2258 return klass;
2259
2260 // Now look to see if it has been loaded elsewhere, and is subject to
2261 // a loader constraint that would require this loader to return the
2262 // klass that is already loaded.
2263 if (FieldType::is_array(class_name)) {
2264 // For array classes, their Klass*s are not kept in the
2265 // constraint table. The element Klass*s are.
2266 FieldArrayInfo fd;
2267 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2268 if (t != T_OBJECT) {
2269 klass = Universe::typeArrayKlassObj(t);
2270 } else {
2271 MutexLocker mu(SystemDictionary_lock, THREAD);
2272 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2273 }
2274 // If element class already loaded, allocate array klass
2275 if (klass != NULL) {
2276 klass = klass->array_klass_or_null(fd.dimension());
2277 }
2278 } else {
2279 MutexLocker mu(SystemDictionary_lock, THREAD);
2280 // Non-array classes are easy: simply check the constraint table.
2281 klass = constraints()->find_constrained_klass(class_name, class_loader);
2282 }
2283
2284 return klass;
2285 }
2286
2287
2288 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2289 Handle class_loader1,
2290 Handle class_loader2,
2291 Thread* THREAD) {
2292 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2293 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2294
2295 Symbol* constraint_name = NULL;
2296 if (!FieldType::is_array(class_name)) {
2297 constraint_name = class_name;
2298 } else {
2299 // For array classes, their Klass*s are not kept in the
2300 // constraint table. The element classes are.
2301 FieldArrayInfo fd;
2302 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2303 // primitive types always pass
2304 if (t != T_OBJECT) {
2305 return true;
2306 } else {
2307 constraint_name = fd.object_key();
2308 }
2309 }
2310
2311 Dictionary* dictionary1 = loader_data1->dictionary();
2312 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2313
2314 Dictionary* dictionary2 = loader_data2->dictionary();
2315 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2316
2317 {
2318 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2319 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2320 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2321 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2322 klass2, class_loader2);
2323 }
2324 }
2325
2326 // Add entry to resolution error table to record the error when the first
2327 // attempt to resolve a reference to a class has failed.
2328 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2329 Symbol* error, Symbol* message) {
2330 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2331 int index = resolution_errors()->hash_to_index(hash);
2332 {
2333 MutexLocker ml(SystemDictionary_lock, Thread::current());
2334 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2335 }
2336 }
2337
2338 // Delete a resolution error for RedefineClasses for a constant pool is going away
2339 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2340 resolution_errors()->delete_entry(pool);
2341 }
2342
2343 // Lookup resolution error table. Returns error if found, otherwise NULL.
2344 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2345 Symbol** message) {
2346 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2347 int index = resolution_errors()->hash_to_index(hash);
2348 {
2349 MutexLocker ml(SystemDictionary_lock, Thread::current());
2350 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2351 if (entry != NULL) {
2352 *message = entry->message();
2353 return entry->error();
2354 } else {
2355 return NULL;
2356 }
2357 }
2358 }
2359
2360
2361 // Signature constraints ensure that callers and callees agree about
2362 // the meaning of type names in their signatures. This routine is the
2363 // intake for constraints. It collects them from several places:
2364 //
2365 // * LinkResolver::resolve_method (if check_access is true) requires
2366 // that the resolving class (the caller) and the defining class of
2367 // the resolved method (the callee) agree on each type in the
2368 // method's signature.
2369 //
2370 // * LinkResolver::resolve_interface_method performs exactly the same
2371 // checks.
2372 //
2373 // * LinkResolver::resolve_field requires that the constant pool
2374 // attempting to link to a field agree with the field's defining
2375 // class about the type of the field signature.
2376 //
2377 // * klassVtable::initialize_vtable requires that, when a class
2378 // overrides a vtable entry allocated by a superclass, that the
2379 // overriding method (i.e., the callee) agree with the superclass
2380 // on each type in the method's signature.
2381 //
2382 // * klassItable::initialize_itable requires that, when a class fills
2383 // in its itables, for each non-abstract method installed in an
2384 // itable, the method (i.e., the callee) agree with the interface
2385 // on each type in the method's signature.
2386 //
2387 // All those methods have a boolean (check_access, checkconstraints)
2388 // which turns off the checks. This is used from specialized contexts
2389 // such as bootstrapping, dumping, and debugging.
2390 //
2391 // No direct constraint is placed between the class and its
2392 // supertypes. Constraints are only placed along linked relations
2393 // between callers and callees. When a method overrides or implements
2394 // an abstract method in a supertype (superclass or interface), the
2395 // constraints are placed as if the supertype were the caller to the
2396 // overriding method. (This works well, since callers to the
2397 // supertype have already established agreement between themselves and
2398 // the supertype.) As a result of all this, a class can disagree with
2399 // its supertype about the meaning of a type name, as long as that
2400 // class neither calls a relevant method of the supertype, nor is
2401 // called (perhaps via an override) from the supertype.
2402 //
2403 //
2404 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2405 //
2406 // Make sure all class components (including arrays) in the given
2407 // signature will be resolved to the same class in both loaders.
2408 // Returns the name of the type that failed a loader constraint check, or
2409 // NULL if no constraint failed. No exception except OOME is thrown.
2410 // Arrays are not added to the loader constraint table, their elements are.
2411 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2412 Handle loader1, Handle loader2,
2413 bool is_method, TRAPS) {
2414 // Nothing to do if loaders are the same.
2415 if (oopDesc::equals(loader1(), loader2())) {
2416 return NULL;
2417 }
2418
2419 SignatureStream sig_strm(signature, is_method);
2420 while (!sig_strm.is_done()) {
2421 if (sig_strm.is_object()) {
2422 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2423 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2424 return sig;
2425 }
2426 }
2427 sig_strm.next();
2428 }
2429 return NULL;
2430 }
2431
2432
2433 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2434 Symbol* signature,
2435 TRAPS) {
2436 methodHandle empty;
2437 assert(MethodHandles::is_signature_polymorphic(iid) &&
2438 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2439 iid != vmIntrinsics::_invokeGeneric,
2440 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2441
2442 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2443 int index = invoke_method_table()->hash_to_index(hash);
2444 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2445 methodHandle m;
2446 if (spe == NULL || spe->method() == NULL) {
2447 spe = NULL;
2448 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2449 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2450 if (!Arguments::is_interpreter_only()) {
2451 // Generate a compiled form of the MH intrinsic.
2452 AdapterHandlerLibrary::create_native_wrapper(m);
2453 // Check if have the compiled code.
2454 if (!m->has_compiled_code()) {
2455 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2456 "Out of space in CodeCache for method handle intrinsic", empty);
2457 }
2458 }
2459 // Now grab the lock. We might have to throw away the new method,
2460 // if a racing thread has managed to install one at the same time.
2461 {
2462 MutexLocker ml(SystemDictionary_lock, THREAD);
2463 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2464 if (spe == NULL)
2465 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2466 if (spe->method() == NULL)
2467 spe->set_method(m());
2468 }
2469 }
2470
2471 assert(spe != NULL && spe->method() != NULL, "");
2472 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2473 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2474 "MH intrinsic invariant");
2475 return spe->method();
2476 }
2477
2478 // Helper for unpacking the return value from linkMethod and linkCallSite.
2479 static methodHandle unpack_method_and_appendix(Handle mname,
2480 Klass* accessing_klass,
2481 objArrayHandle appendix_box,
2482 Handle* appendix_result,
2483 TRAPS) {
2484 methodHandle empty;
2485 if (mname.not_null()) {
2486 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2487 if (m != NULL) {
2488 oop appendix = appendix_box->obj_at(0);
2489 if (TraceMethodHandles) {
2490 #ifndef PRODUCT
2491 ttyLocker ttyl;
2492 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2493 m->print();
2494 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2495 tty->cr();
2496 #endif //PRODUCT
2497 }
2498 (*appendix_result) = Handle(THREAD, appendix);
2499 // the target is stored in the cpCache and if a reference to this
2500 // MemberName is dropped we need a way to make sure the
2501 // class_loader containing this method is kept alive.
2502 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2503 this_key->record_dependency(m->method_holder());
2504 return methodHandle(THREAD, m);
2505 }
2506 }
2507 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2508 return empty;
2509 }
2510
2511 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2512 Symbol* name,
2513 Symbol* signature,
2514 Klass* accessing_klass,
2515 Handle *appendix_result,
2516 Handle *method_type_result,
2517 TRAPS) {
2518 methodHandle empty;
2519 assert(THREAD->can_call_java() ,"");
2520 Handle method_type =
2521 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2522
2523 int ref_kind = JVM_REF_invokeVirtual;
2524 oop name_oop = StringTable::intern(name, CHECK_(empty));
2525 Handle name_str (THREAD, name_oop);
2526 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2527 assert(appendix_box->obj_at(0) == NULL, "");
2528
2529 // This should not happen. JDK code should take care of that.
2530 if (accessing_klass == NULL || method_type.is_null()) {
2531 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2532 }
2533
2534 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2535 JavaCallArguments args;
2536 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2537 args.push_int(ref_kind);
2538 args.push_oop(Handle(THREAD, klass->java_mirror()));
2539 args.push_oop(name_str);
2540 args.push_oop(method_type);
2541 args.push_oop(appendix_box);
2542 JavaValue result(T_OBJECT);
2543 JavaCalls::call_static(&result,
2544 SystemDictionary::MethodHandleNatives_klass(),
2545 vmSymbols::linkMethod_name(),
2546 vmSymbols::linkMethod_signature(),
2547 &args, CHECK_(empty));
2548 Handle mname(THREAD, (oop) result.get_jobject());
2549 (*method_type_result) = method_type;
2550 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2551 }
2552
2553 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2554 // We must ensure that all class loaders everywhere will reach this class, for any client.
2555 // This is a safe bet for public classes in java.lang, such as Object and String.
2556 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2557 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2558 static bool is_always_visible_class(oop mirror) {
2559 Klass* klass = java_lang_Class::as_Klass(mirror);
2560 if (klass->is_objArray_klass()) {
2561 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2562 }
2563 if (klass->is_typeArray_klass()) {
2564 return true; // primitive array
2565 }
2566 assert(klass->is_instance_klass(), "%s", klass->external_name());
2567 return klass->is_public() &&
2568 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2569 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2570 }
2571
2572
2573 // Return the Java mirror (java.lang.Class instance) for a single-character
2574 // descriptor. This result, when available, is the same as produced by the
2575 // heavier API point of the same name that takes a Symbol.
2576 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2577 return java_lang_Class::primitive_mirror(char2type(signature_char));
2578 }
2579
2580 // Find or construct the Java mirror (java.lang.Class instance) for a
2581 // for the given field type signature, as interpreted relative to the
2582 // given class loader. Handles primitives, void, references, arrays,
2583 // and all other reflectable types, except method types.
2584 // N.B. Code in reflection should use this entry point.
2585 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2586 Klass* accessing_klass,
2587 Handle class_loader,
2588 Handle protection_domain,
2589 SignatureStream::FailureMode failure_mode,
2590 TRAPS) {
2591 Handle empty;
2592
2593 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2594 "one or the other, or perhaps neither");
2595
2596 Symbol* type = signature;
2597
2598 // What we have here must be a valid field descriptor,
2599 // and all valid field descriptors are supported.
2600 // Produce the same java.lang.Class that reflection reports.
2601 if (type->utf8_length() == 1) {
2602
2603 // It's a primitive. (Void has a primitive mirror too.)
2604 char ch = (char) type->byte_at(0);
2605 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2606 return Handle(THREAD, find_java_mirror_for_type(ch));
2607
2608 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2609
2610 // It's a reference type.
2611 if (accessing_klass != NULL) {
2612 class_loader = Handle(THREAD, accessing_klass->class_loader());
2613 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2614 }
2615 Klass* constant_type_klass;
2616 if (failure_mode == SignatureStream::ReturnNull) {
2617 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2618 CHECK_(empty));
2619 } else {
2620 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2621 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2622 throw_error, CHECK_(empty));
2623 }
2624 if (constant_type_klass == NULL) {
2625 return Handle(); // report failure this way
2626 }
2627 Handle mirror(THREAD, constant_type_klass->java_mirror());
2628
2629 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2630 if (accessing_klass != NULL) {
2631 Klass* sel_klass = constant_type_klass;
2632 bool fold_type_to_class = true;
2633 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2634 fold_type_to_class, CHECK_(empty));
2635 }
2636
2637 return mirror;
2638
2639 }
2640
2641 // Fall through to an error.
2642 assert(false, "unsupported mirror syntax");
2643 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2644 }
2645
2646
2647 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2648 // signature, as interpreted relative to the given class loader.
2649 // Because of class loader constraints, all method handle usage must be
2650 // consistent with this loader.
2651 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2652 Klass* accessing_klass,
2653 TRAPS) {
2654 Handle empty;
2655 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2656 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2657 int index = invoke_method_table()->hash_to_index(hash);
2658 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2659 if (spe != NULL && spe->method_type() != NULL) {
2660 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2661 return Handle(THREAD, spe->method_type());
2662 } else if (!THREAD->can_call_java()) {
2663 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2664 return Handle(); // do not attempt from within compiler, unless it was cached
2665 }
2666
2667 Handle class_loader, protection_domain;
2668 if (accessing_klass != NULL) {
2669 class_loader = Handle(THREAD, accessing_klass->class_loader());
2670 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2671 }
2672 bool can_be_cached = true;
2673 int npts = ArgumentCount(signature).size();
2674 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2675 int arg = 0;
2676 Handle rt; // the return type from the signature
2677 ResourceMark rm(THREAD);
2678 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2679 oop mirror = NULL;
2680 if (can_be_cached) {
2681 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2682 mirror = ss.as_java_mirror(Handle(), Handle(),
2683 SignatureStream::ReturnNull, CHECK_(empty));
2684 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2685 // Fall back to accessing_klass context.
2686 can_be_cached = false;
2687 }
2688 }
2689 if (!can_be_cached) {
2690 // Resolve, throwing a real error if it doesn't work.
2691 mirror = ss.as_java_mirror(class_loader, protection_domain,
2692 SignatureStream::NCDFError, CHECK_(empty));
2693 }
2694 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2695 if (ss.at_return_type())
2696 rt = Handle(THREAD, mirror);
2697 else
2698 pts->obj_at_put(arg++, mirror);
2699
2700 // Check accessibility.
2701 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2702 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2703 mirror = NULL; // safety
2704 // Emulate ConstantPool::verify_constant_pool_resolve.
2705 bool fold_type_to_class = true;
2706 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2707 fold_type_to_class, CHECK_(empty));
2708 }
2709 }
2710 assert(arg == npts, "");
2711
2712 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2713 JavaCallArguments args(Handle(THREAD, rt()));
2714 args.push_oop(pts);
2715 JavaValue result(T_OBJECT);
2716 JavaCalls::call_static(&result,
2717 SystemDictionary::MethodHandleNatives_klass(),
2718 vmSymbols::findMethodHandleType_name(),
2719 vmSymbols::findMethodHandleType_signature(),
2720 &args, CHECK_(empty));
2721 Handle method_type(THREAD, (oop) result.get_jobject());
2722
2723 if (can_be_cached) {
2724 // We can cache this MethodType inside the JVM.
2725 MutexLocker ml(SystemDictionary_lock, THREAD);
2726 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2727 if (spe == NULL)
2728 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2729 if (spe->method_type() == NULL) {
2730 spe->set_method_type(method_type());
2731 }
2732 }
2733
2734 // report back to the caller with the MethodType
2735 return method_type;
2736 }
2737
2738 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2739 Klass* accessing_klass,
2740 TRAPS) {
2741 Handle empty;
2742 ResourceMark rm(THREAD);
2743 SignatureStream ss(signature, /*is_method=*/ false);
2744 if (!ss.is_done()) {
2745 Handle class_loader, protection_domain;
2746 if (accessing_klass != NULL) {
2747 class_loader = Handle(THREAD, accessing_klass->class_loader());
2748 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2749 }
2750 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2751 ss.next();
2752 if (ss.is_done()) {
2753 return Handle(THREAD, mirror);
2754 }
2755 }
2756 return empty;
2757 }
2758
2759 // Ask Java code to find or construct a method handle constant.
2760 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2761 int ref_kind, //e.g., JVM_REF_invokeVirtual
2762 Klass* callee,
2763 Symbol* name,
2764 Symbol* signature,
2765 TRAPS) {
2766 Handle empty;
2767 if (caller == NULL) {
2768 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2769 }
2770 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2771 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2772
2773 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2774 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2775 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2776 java_lang_invoke_MemberName::set_name (mname(), name_str());
2777 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2778 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2779
2780 if (ref_kind == JVM_REF_invokeVirtual &&
2781 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2782 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2783 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2784 // They are public signature polymorphic methods, but require appendix argument
2785 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2786 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2787 } else {
2788 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2789 }
2790
2791 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2792 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2793
2794 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2795 JavaCallArguments args;
2796 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2797 args.push_int(ref_kind);
2798 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2799 args.push_oop(name_str);
2800 args.push_oop(type);
2801 JavaValue result(T_OBJECT);
2802 JavaCalls::call_static(&result,
2803 SystemDictionary::MethodHandleNatives_klass(),
2804 vmSymbols::linkMethodHandleConstant_name(),
2805 vmSymbols::linkMethodHandleConstant_signature(),
2806 &args, CHECK_(empty));
2807 return Handle(THREAD, (oop) result.get_jobject());
2808 }
2809
2810 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2811 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2812 int condy_index,
2813 Handle bootstrap_specifier,
2814 Symbol* name,
2815 Symbol* type,
2816 TRAPS) {
2817 Handle empty;
2818 Handle bsm, info;
2819 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2820 bsm = bootstrap_specifier;
2821 } else {
2822 assert(bootstrap_specifier->is_objArray(), "");
2823 objArrayOop args = (objArrayOop) bootstrap_specifier();
2824 assert(args->length() == 2, "");
2825 bsm = Handle(THREAD, args->obj_at(0));
2826 info = Handle(THREAD, args->obj_at(1));
2827 }
2828 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2829 "caller must supply a valid BSM");
2830
2831 // This should not happen. JDK code should take care of that.
2832 if (caller == NULL) {
2833 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2834 }
2835
2836 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2837
2838 // Resolve the constant type in the context of the caller class
2839 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2840 CHECK_(empty));
2841
2842 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2843 JavaCallArguments args;
2844 args.push_oop(Handle(THREAD, caller->java_mirror()));
2845 args.push_int(condy_index);
2846 args.push_oop(bsm);
2847 args.push_oop(constant_name);
2848 args.push_oop(type_mirror);
2849 args.push_oop(info);
2850 JavaValue result(T_OBJECT);
2851 JavaCalls::call_static(&result,
2852 SystemDictionary::MethodHandleNatives_klass(),
2853 vmSymbols::linkDynamicConstant_name(),
2854 vmSymbols::linkDynamicConstant_signature(),
2855 &args, CHECK_(empty));
2856
2857 return Handle(THREAD, (oop) result.get_jobject());
2858 }
2859
2860 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2861 // name and signature, as interpreted relative to the given class loader.
2862 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2863 int indy_index,
2864 Handle bootstrap_specifier,
2865 Symbol* name,
2866 Symbol* type,
2867 Handle *appendix_result,
2868 Handle *method_type_result,
2869 TRAPS) {
2870 methodHandle empty;
2871 Handle bsm, info;
2872 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2873 bsm = bootstrap_specifier;
2874 } else {
2875 objArrayOop args = (objArrayOop) bootstrap_specifier();
2876 assert(args->length() == 2, "");
2877 bsm = Handle(THREAD, args->obj_at(0));
2878 info = Handle(THREAD, args->obj_at(1));
2879 }
2880 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2881 "caller must supply a valid BSM");
2882
2883 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2884 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2885
2886 // This should not happen. JDK code should take care of that.
2887 if (caller == NULL || method_type.is_null()) {
2888 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2889 }
2890
2891 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2892 assert(appendix_box->obj_at(0) == NULL, "");
2893
2894 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2895 JavaCallArguments args;
2896 args.push_oop(Handle(THREAD, caller->java_mirror()));
2897 args.push_int(indy_index);
2898 args.push_oop(bsm);
2899 args.push_oop(method_name);
2900 args.push_oop(method_type);
2901 args.push_oop(info);
2902 args.push_oop(appendix_box);
2903 JavaValue result(T_OBJECT);
2904 JavaCalls::call_static(&result,
2905 SystemDictionary::MethodHandleNatives_klass(),
2906 vmSymbols::linkCallSite_name(),
2907 vmSymbols::linkCallSite_signature(),
2908 &args, CHECK_(empty));
2909 Handle mname(THREAD, (oop) result.get_jobject());
2910 (*method_type_result) = method_type;
2911 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2912 }
2913
2914 // Protection domain cache table handling
2915
2916 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2917 return _pd_cache_table->get(protection_domain);
2918 }
2919
2920 #if INCLUDE_CDS
2921 void SystemDictionary::reorder_dictionary_for_sharing() {
2922 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2923 }
2924 #endif
2925
2926 size_t SystemDictionary::count_bytes_for_buckets() {
2927 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2928 }
2929
2930 size_t SystemDictionary::count_bytes_for_table() {
2931 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2932 }
2933
2934 void SystemDictionary::copy_buckets(char* top, char* end) {
2935 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2936 }
2937
2938 void SystemDictionary::copy_table(char* top, char* end) {
2939 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2940 }
2941
2942 // ----------------------------------------------------------------------------
2943 void SystemDictionary::print_shared(outputStream *st) {
2944 shared_dictionary()->print_on(st);
2945 }
2946
2947 void SystemDictionary::print_on(outputStream *st) {
2948 if (shared_dictionary() != NULL) {
2949 st->print_cr("Shared Dictionary");
2950 shared_dictionary()->print_on(st);
2951 st->cr();
2952 }
2953
2954 GCMutexLocker mu(SystemDictionary_lock);
2955
2956 ClassLoaderDataGraph::print_dictionary(st);
2957
2958 // Placeholders
2959 placeholders()->print_on(st);
2960 st->cr();
2961
2962 // loader constraints - print under SD_lock
2963 constraints()->print_on(st);
2964 st->cr();
2965
2966 _pd_cache_table->print_on(st);
2967 st->cr();
2968 }
2969
2970 void SystemDictionary::verify() {
2971 guarantee(constraints() != NULL,
2972 "Verify of loader constraints failed");
2973 guarantee(placeholders()->number_of_entries() >= 0,
2974 "Verify of placeholders failed");
2975
2976 GCMutexLocker mu(SystemDictionary_lock);
2977
2978 // Verify dictionary
2979 ClassLoaderDataGraph::verify_dictionary();
2980
2981 placeholders()->verify();
2982
2983 // Verify constraint table
2984 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2985 constraints()->verify(placeholders());
2986
2987 _pd_cache_table->verify();
2988 }
2989
2990 void SystemDictionary::dump(outputStream *st, bool verbose) {
2991 assert_locked_or_safepoint(SystemDictionary_lock);
2992 if (verbose) {
2993 print_on(st);
2994 } else {
2995 if (shared_dictionary() != NULL) {
2996 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2997 }
2998 ClassLoaderDataGraph::print_dictionary_statistics(st);
2999 placeholders()->print_table_statistics(st, "Placeholder Table");
3000 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3001 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3002 }
3003 }
3004
3005 // Utility for dumping dictionaries.
3006 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3007 DCmdWithParser(output, heap),
3008 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3009 "BOOLEAN", false, "false") {
3010 _dcmdparser.add_dcmd_option(&_verbose);
3011 }
3012
3013 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3014 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3015 _verbose.value());
3016 VMThread::execute(&dumper);
3017 }
3018
3019 int SystemDictionaryDCmd::num_arguments() {
3020 ResourceMark rm;
3021 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3022 if (dcmd != NULL) {
3023 DCmdMark mark(dcmd);
3024 return dcmd->_dcmdparser.num_arguments();
3025 } else {
3026 return 0;
3027 }
3028 }
3029
3030 class CombineDictionariesClosure : public CLDClosure {
3031 private:
3032 Dictionary* _master_dictionary;
3033 public:
3034 CombineDictionariesClosure(Dictionary* master_dictionary) :
3035 _master_dictionary(master_dictionary) {}
3036 void do_cld(ClassLoaderData* cld) {
3037 ResourceMark rm;
3038 if (cld->is_anonymous()) {
3039 return;
3040 }
3041 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3042 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3043 Dictionary* curr_dictionary = cld->dictionary();
3044 DictionaryEntry* p = curr_dictionary->bucket(i);
3045 while (p != NULL) {
3046 Symbol* name = p->instance_klass()->name();
3047 unsigned int d_hash = _master_dictionary->compute_hash(name);
3048 int d_index = _master_dictionary->hash_to_index(d_hash);
3049 DictionaryEntry* next = p->next();
3050 if (p->literal()->class_loader_data() != cld) {
3051 // This is an initiating class loader entry; don't use it
3052 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3053 curr_dictionary->free_entry(p);
3054 } else {
3055 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3056 curr_dictionary->unlink_entry(p);
3057 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3058 _master_dictionary->add_entry(d_index, p);
3059 }
3060 p = next;
3061 }
3062 *curr_dictionary->bucket_addr(i) = NULL;
3063 }
3064 }
3065 }
3066 };
3067
3068 // Combining platform and system loader dictionaries into boot loader dictionary.
3069 // During run time, we only have one shared dictionary.
3070 void SystemDictionary::combine_shared_dictionaries() {
3071 assert(DumpSharedSpaces, "dump time only");
3072 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3073 CombineDictionariesClosure cdc(master_dictionary);
3074 ClassLoaderDataGraph::cld_do(&cdc);
3075
3076 // These tables are no longer valid or necessary. Keeping them around will
3077 // cause SystemDictionary::verify() to fail. Let's empty them.
3078 _placeholders = new PlaceholderTable(_placeholder_table_size);
3079 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3080
3081 NOT_PRODUCT(SystemDictionary::verify());
3082 }
3083
3084 // caller needs ResourceMark
3085 const char* SystemDictionary::loader_name(const oop loader) {
3086 return ((loader) == NULL ? "<bootloader>" :
3087 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3088 }
3089
3090 // caller needs ResourceMark
3091 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3092 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3093 SystemDictionary::loader_name(loader_data->class_loader()));
3094 }
3095
3096 void SystemDictionary::initialize_oop_storage() {
3097 _vm_weak_oop_storage =
3098 new OopStorage("VM Weak Oop Handles",
3099 VMWeakAlloc_lock,
3100 VMWeakActive_lock);
3101 }
3102
3103 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3104 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3105 return _vm_weak_oop_storage;
3106 }