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