1 /*
2 * Copyright (c) 1997, 2017, 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 "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/protectionDomainCache.hpp"
39 #include "classfile/resolutionErrors.hpp"
40 #include "classfile/stringTable.hpp"
41 #include "classfile/systemDictionary.hpp"
42 #include "classfile/vmSymbols.hpp"
43 #include "code/codeCache.hpp"
44 #include "compiler/compileBroker.hpp"
45 #include "gc/shared/gcLocker.hpp"
46 #include "gc/shared/gcTraceTime.inline.hpp"
47 #include "interpreter/bytecodeStream.hpp"
48 #include "interpreter/interpreter.hpp"
49 #include "logging/log.hpp"
50 #include "logging/logStream.hpp"
51 #include "memory/filemap.hpp"
52 #include "memory/metaspaceClosure.hpp"
53 #include "memory/oopFactory.hpp"
54 #include "memory/resourceArea.hpp"
55 #include "oops/instanceKlass.hpp"
56 #include "oops/instanceRefKlass.hpp"
57 #include "oops/klass.inline.hpp"
58 #include "oops/methodData.hpp"
59 #include "oops/objArrayKlass.hpp"
60 #include "oops/objArrayOop.inline.hpp"
61 #include "oops/oop.inline.hpp"
62 #include "oops/symbol.hpp"
63 #include "oops/typeArrayKlass.hpp"
64 #include "prims/jvm.h"
65 #include "prims/jvmtiEnvBase.hpp"
66 #include "prims/resolvedMethodTable.hpp"
67 #include "prims/methodHandles.hpp"
68 #include "runtime/arguments.hpp"
69 #include "runtime/arguments_ext.hpp"
70 #include "runtime/biasedLocking.hpp"
71 #include "runtime/fieldType.hpp"
72 #include "runtime/handles.inline.hpp"
73 #include "runtime/java.hpp"
74 #include "runtime/javaCalls.hpp"
75 #include "runtime/mutexLocker.hpp"
76 #include "runtime/orderAccess.inline.hpp"
77 #include "runtime/signature.hpp"
78 #include "services/classLoadingService.hpp"
79 #include "services/diagnosticCommand.hpp"
80 #include "services/threadService.hpp"
81 #include "trace/tracing.hpp"
82 #include "utilities/macros.hpp"
83 #if INCLUDE_CDS
84 #include "classfile/sharedClassUtil.hpp"
85 #include "classfile/systemDictionaryShared.hpp"
86 #endif
87 #if INCLUDE_JVMCI
88 #include "jvmci/jvmciRuntime.hpp"
89 #endif
90
91 PlaceholderTable* SystemDictionary::_placeholders = NULL;
92 Dictionary* SystemDictionary::_shared_dictionary = NULL;
93 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
94 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
95 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
96 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
97
98 int SystemDictionary::_number_of_modifications = 0;
99 oop SystemDictionary::_system_loader_lock_obj = NULL;
100
101 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
102 = { NULL /*, NULL...*/ };
103
104 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
105
106 oop SystemDictionary::_java_system_loader = NULL;
107
108 bool SystemDictionary::_has_loadClassInternal = false;
109 bool SystemDictionary::_has_checkPackageAccess = false;
110
111 // lazily initialized klass variables
112 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
113
114 // Default ProtectionDomainCacheSize value
115
116 const int defaultProtectionDomainCacheSize = 1009;
117
118
119 // ----------------------------------------------------------------------------
120 // Java-level SystemLoader
121
122 oop SystemDictionary::java_system_loader() {
123 return _java_system_loader;
124 }
125
126 void SystemDictionary::compute_java_system_loader(TRAPS) {
127 Klass* system_klass = WK_KLASS(ClassLoader_klass);
128 JavaValue result(T_OBJECT);
129 JavaCalls::call_static(&result,
130 WK_KLASS(ClassLoader_klass),
131 vmSymbols::getSystemClassLoader_name(),
132 vmSymbols::void_classloader_signature(),
133 CHECK);
134
135 _java_system_loader = (oop)result.get_jobject();
136
137 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
138 }
139
140
141 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
142 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
143 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
144 }
145
146 // ----------------------------------------------------------------------------
147 // Parallel class loading check
148
149 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
150 if (UnsyncloadClass || class_loader.is_null()) return true;
151 if (AlwaysLockClassLoader) return false;
152 return java_lang_ClassLoader::parallelCapable(class_loader());
153 }
154 // ----------------------------------------------------------------------------
155 // ParallelDefineClass flag does not apply to bootclass loader
156 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
157 if (class_loader.is_null()) return false;
158 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
159 return true;
160 }
161 return false;
162 }
163
164 // Returns true if the passed class loader is the builtin application class loader
165 // or a custom system class loader. A customer system class loader can be
166 // specified via -Djava.system.class.loader.
167 bool SystemDictionary::is_system_class_loader(oop class_loader) {
168 if (class_loader == NULL) {
169 return false;
170 }
171 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
172 class_loader == _java_system_loader);
173 }
174
175 // Returns true if the passed class loader is the platform class loader.
176 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
177 if (class_loader == NULL) {
178 return false;
179 }
180 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
181 }
182
183 // ----------------------------------------------------------------------------
184 // Resolving of classes
185
186 // Forwards to resolve_or_null
187
188 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
189 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
190 if (HAS_PENDING_EXCEPTION || klass == NULL) {
191 // can return a null klass
192 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
193 }
194 return klass;
195 }
196
197 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
198 bool throw_error,
199 Klass* klass, TRAPS) {
200 if (HAS_PENDING_EXCEPTION) {
201 // If we have a pending exception we forward it to the caller, unless throw_error is true,
202 // in which case we have to check whether the pending exception is a ClassNotFoundException,
203 // and if so convert it to a NoClassDefFoundError
204 // And chain the original ClassNotFoundException
205 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
206 ResourceMark rm(THREAD);
207 assert(klass == NULL, "Should not have result with exception pending");
208 Handle e(THREAD, PENDING_EXCEPTION);
209 CLEAR_PENDING_EXCEPTION;
210 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
211 } else {
212 return NULL;
213 }
214 }
215 // Class not found, throw appropriate error or exception depending on value of throw_error
216 if (klass == NULL) {
217 ResourceMark rm(THREAD);
218 if (throw_error) {
219 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
220 } else {
221 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
222 }
223 }
224 return klass;
225 }
226
227
228 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
229 bool throw_error, TRAPS)
230 {
231 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
232 }
233
234
235 // Forwards to resolve_instance_class_or_null
236
237 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
238 assert(THREAD->can_call_java(),
239 "can not load classes with compiler thread: class=%s, classloader=%s",
240 class_name->as_C_string(),
241 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
242 if (FieldType::is_array(class_name)) {
243 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
244 } else if (FieldType::is_obj(class_name)) {
245 ResourceMark rm(THREAD);
246 // Ignore wrapping L and ;.
247 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
248 class_name->utf8_length() - 2, CHECK_NULL);
249 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
250 } else {
251 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
252 }
253 }
254
255 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
256 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
257 }
258
259 // Forwards to resolve_instance_class_or_null
260
261 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
262 Handle class_loader,
263 Handle protection_domain,
264 TRAPS) {
265 assert(FieldType::is_array(class_name), "must be array");
266 Klass* k = NULL;
267 FieldArrayInfo fd;
268 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
269 // of this call
270 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
271 if (t == T_OBJECT) {
272 // naked oop "k" is OK here -- we assign back into it
273 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
274 class_loader,
275 protection_domain,
276 CHECK_NULL);
277 if (k != NULL) {
278 k = k->array_klass(fd.dimension(), CHECK_NULL);
279 }
280 } else {
281 k = Universe::typeArrayKlassObj(t);
282 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
283 }
284 return k;
285 }
286
287
288 // Must be called for any super-class or super-interface resolution
289 // during class definition to allow class circularity checking
290 // super-interface callers:
291 // parse_interfaces - for defineClass & jvmtiRedefineClasses
292 // super-class callers:
293 // ClassFileParser - for defineClass & jvmtiRedefineClasses
294 // load_shared_class - while loading a class from shared archive
295 // resolve_instance_class_or_null:
296 // via: handle_parallel_super_load
297 // when resolving a class that has an existing placeholder with
298 // a saved superclass [i.e. a defineClass is currently in progress]
299 // if another thread is trying to resolve the class, it must do
300 // super-class checks on its own thread to catch class circularity
301 // This last call is critical in class circularity checking for cases
302 // where classloading is delegated to different threads and the
303 // classloader lock is released.
304 // Take the case: Base->Super->Base
305 // 1. If thread T1 tries to do a defineClass of class Base
306 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
307 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
308 // so it tries to load Super
309 // 3. If we load the class internally, or user classloader uses same thread
310 // loadClassFromxxx or defineClass via parseClassFile Super ...
311 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
312 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
313 // 3.4 calls resolve_super_or_fail Base
314 // 3.5 finds T1,Base -> throws class circularity
315 //OR 4. If T2 tries to resolve Super via defineClass Super ...
316 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
317 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
318 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
319 // 4.4 finds T2, Super -> throws class circularity
320 // Must be called, even if superclass is null, since this is
321 // where the placeholder entry is created which claims this
322 // thread is loading this class/classloader.
323 // Be careful when modifying this code: once you have run
324 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
325 // you need to find_and_remove it before returning.
326 // So be careful to not exit with a CHECK_ macro betweeen these calls.
327 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
328 Symbol* class_name,
329 Handle class_loader,
330 Handle protection_domain,
331 bool is_superclass,
332 TRAPS) {
333 #if INCLUDE_CDS
334 if (DumpSharedSpaces) {
335 // Special processing for CDS dump time.
336 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
337 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
338 if (k) {
339 return k;
340 }
341 }
342 #endif // INCLUDE_CDS
343
344 // Double-check, if child class is already loaded, just return super-class,interface
345 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
346 // dictionary.
347 // Make sure there's a placeholder for the *child* before resolving.
348 // Used as a claim that this thread is currently loading superclass/classloader
349 // Used here for ClassCircularity checks and also for heap verification
350 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
351 // Must check ClassCircularity before checking if super class is already loaded.
352 //
353 // We might not already have a placeholder if this child_name was
354 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
355 // the name of the class might not be known until the stream is actually
356 // parsed.
357 // Bugs 4643874, 4715493
358
359 ClassLoaderData* loader_data = class_loader_data(class_loader);
360 Dictionary* dictionary = loader_data->dictionary();
361 unsigned int d_hash = dictionary->compute_hash(child_name);
362 int d_index = dictionary->hash_to_index(d_hash);
363 unsigned int p_hash = placeholders()->compute_hash(child_name);
364 int p_index = placeholders()->hash_to_index(p_hash);
365 // can't throw error holding a lock
366 bool child_already_loaded = false;
367 bool throw_circularity_error = false;
368 {
369 MutexLocker mu(SystemDictionary_lock, THREAD);
370 Klass* childk = find_class(d_index, d_hash, child_name, dictionary);
371 Klass* quicksuperk;
372 // to support // loading: if child done loading, just return superclass
373 // if class_name, & class_loader don't match:
374 // if initial define, SD update will give LinkageError
375 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
376 // so we don't throw an exception here.
377 // see: nsk redefclass014 & java.lang.instrument Instrument032
378 if ((childk != NULL ) && (is_superclass) &&
379 ((quicksuperk = childk->super()) != NULL) &&
380
381 ((quicksuperk->name() == class_name) &&
382 (quicksuperk->class_loader() == class_loader()))) {
383 return quicksuperk;
384 } else {
385 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
386 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
387 throw_circularity_error = true;
388 }
389 }
390 if (!throw_circularity_error) {
391 // Be careful not to exit resolve_super
392 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
393 }
394 }
395 if (throw_circularity_error) {
396 ResourceMark rm(THREAD);
397 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
398 }
399
400 // java.lang.Object should have been found above
401 assert(class_name != NULL, "null super class for resolving");
402 // Resolve the super class or interface, check results on return
403 Klass* superk = SystemDictionary::resolve_or_null(class_name,
404 class_loader,
405 protection_domain,
406 THREAD);
407
408 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
409 // It is no longer necessary to keep the placeholder table alive until update_dictionary
410 // or error. GC used to walk the placeholder table as strong roots.
411 // The instanceKlass is kept alive because the class loader is on the stack,
412 // which keeps the loader_data alive, as well as all instanceKlasses in
413 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
414 {
415 MutexLocker mu(SystemDictionary_lock, THREAD);
416 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
417 SystemDictionary_lock->notify_all();
418 }
419 if (HAS_PENDING_EXCEPTION || superk == NULL) {
420 // can null superk
421 superk = handle_resolution_exception(class_name, true, superk, THREAD);
422 }
423
424 return superk;
425 }
426
427 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
428 Handle class_loader,
429 Handle protection_domain,
430 TRAPS) {
431 if(!has_checkPackageAccess()) return;
432
433 // Now we have to call back to java to check if the initating class has access
434 JavaValue result(T_VOID);
435 LogTarget(Debug, protectiondomain) lt;
436 if (lt.is_enabled()) {
437 ResourceMark rm;
438 // Print out trace information
439 LogStream ls(lt);
440 ls.print_cr("Checking package access");
441 ls.print("class loader: "); class_loader()->print_value_on(&ls);
442 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
443 ls.print(" loading: "); klass->print_value_on(&ls);
444 ls.cr();
445 }
446
447 // This handle and the class_loader handle passed in keeps this class from
448 // being unloaded through several GC points.
449 // The class_loader handle passed in is the initiating loader.
450 Handle mirror(THREAD, klass->java_mirror());
451
452 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
453 JavaCalls::call_special(&result,
454 class_loader,
455 system_loader,
456 vmSymbols::checkPackageAccess_name(),
457 vmSymbols::class_protectiondomain_signature(),
458 mirror,
459 protection_domain,
460 THREAD);
461
462 if (HAS_PENDING_EXCEPTION) {
463 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
464 } else {
465 log_debug(protectiondomain)("granted");
466 }
467
468 if (HAS_PENDING_EXCEPTION) return;
469
470 // If no exception has been thrown, we have validated the protection domain
471 // Insert the protection domain of the initiating class into the set.
472 {
473 ClassLoaderData* loader_data = class_loader_data(class_loader);
474 Dictionary* dictionary = loader_data->dictionary();
475
476 Symbol* kn = klass->name();
477 unsigned int d_hash = dictionary->compute_hash(kn);
478 int d_index = dictionary->hash_to_index(d_hash);
479
480 MutexLocker mu(SystemDictionary_lock, THREAD);
481 dictionary->add_protection_domain(d_index, d_hash, klass,
482 protection_domain, THREAD);
483 }
484 }
485
486 // We only get here if this thread finds that another thread
487 // has already claimed the placeholder token for the current operation,
488 // but that other thread either never owned or gave up the
489 // object lock
490 // Waits on SystemDictionary_lock to indicate placeholder table updated
491 // On return, caller must recheck placeholder table state
492 //
493 // We only get here if
494 // 1) custom classLoader, i.e. not bootstrap classloader
495 // 2) UnsyncloadClass not set
496 // 3) custom classLoader has broken the class loader objectLock
497 // so another thread got here in parallel
498 //
499 // lockObject must be held.
500 // Complicated dance due to lock ordering:
501 // Must first release the classloader object lock to
502 // allow initial definer to complete the class definition
503 // and to avoid deadlock
504 // Reclaim classloader lock object with same original recursion count
505 // Must release SystemDictionary_lock after notify, since
506 // class loader lock must be claimed before SystemDictionary_lock
507 // to prevent deadlocks
508 //
509 // The notify allows applications that did an untimed wait() on
510 // the classloader object lock to not hang.
511 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
512 assert_lock_strong(SystemDictionary_lock);
513
514 bool calledholdinglock
515 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
516 assert(calledholdinglock,"must hold lock for notify");
517 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
518 ObjectSynchronizer::notifyall(lockObject, THREAD);
519 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
520 SystemDictionary_lock->wait();
521 SystemDictionary_lock->unlock();
522 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
523 SystemDictionary_lock->lock();
524 }
525
526 // If the class in is in the placeholder table, class loading is in progress
527 // For cases where the application changes threads to load classes, it
528 // is critical to ClassCircularity detection that we try loading
529 // the superclass on the same thread internally, so we do parallel
530 // super class loading here.
531 // This also is critical in cases where the original thread gets stalled
532 // even in non-circularity situations.
533 // Note: must call resolve_super_or_fail even if null super -
534 // to force placeholder entry creation for this class for circularity detection
535 // Caller must check for pending exception
536 // Returns non-null Klass* if other thread has completed load
537 // and we are done,
538 // If return null Klass* and no pending exception, the caller must load the class
539 InstanceKlass* SystemDictionary::handle_parallel_super_load(
540 Symbol* name, Symbol* superclassname, Handle class_loader,
541 Handle protection_domain, Handle lockObject, TRAPS) {
542
543 ClassLoaderData* loader_data = class_loader_data(class_loader);
544 Dictionary* dictionary = loader_data->dictionary();
545 unsigned int d_hash = dictionary->compute_hash(name);
546 int d_index = dictionary->hash_to_index(d_hash);
547 unsigned int p_hash = placeholders()->compute_hash(name);
548 int p_index = placeholders()->hash_to_index(p_hash);
549
550 // superk is not used, resolve_super called for circularity check only
551 // This code is reached in two situations. One if this thread
552 // is loading the same class twice (e.g. ClassCircularity, or
553 // java.lang.instrument).
554 // The second is if another thread started the resolve_super first
555 // and has not yet finished.
556 // In both cases the original caller will clean up the placeholder
557 // entry on error.
558 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
559 superclassname,
560 class_loader,
561 protection_domain,
562 true,
563 CHECK_NULL);
564
565 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
566 // Serial class loaders and bootstrap classloader do wait for superclass loads
567 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
568 MutexLocker mu(SystemDictionary_lock, THREAD);
569 // Check if classloading completed while we were loading superclass or waiting
570 return find_class(d_index, d_hash, name, dictionary);
571 }
572
573 // must loop to both handle other placeholder updates
574 // and spurious notifications
575 bool super_load_in_progress = true;
576 PlaceholderEntry* placeholder;
577 while (super_load_in_progress) {
578 MutexLocker mu(SystemDictionary_lock, THREAD);
579 // Check if classloading completed while we were loading superclass or waiting
580 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
581 if (check != NULL) {
582 // Klass is already loaded, so just return it
583 return check;
584 } else {
585 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
586 if (placeholder && placeholder->super_load_in_progress() ){
587 // Before UnsyncloadClass:
588 // We only get here if the application has released the
589 // classloader lock when another thread was in the middle of loading a
590 // superclass/superinterface for this class, and now
591 // this thread is also trying to load this class.
592 // To minimize surprises, the first thread that started to
593 // load a class should be the one to complete the loading
594 // with the classfile it initially expected.
595 // This logic has the current thread wait once it has done
596 // all the superclass/superinterface loading it can, until
597 // the original thread completes the class loading or fails
598 // If it completes we will use the resulting InstanceKlass
599 // which we will find below in the systemDictionary.
600 // We also get here for parallel bootstrap classloader
601 if (class_loader.is_null()) {
602 SystemDictionary_lock->wait();
603 } else {
604 double_lock_wait(lockObject, THREAD);
605 }
606 } else {
607 // If not in SD and not in PH, other thread's load must have failed
608 super_load_in_progress = false;
609 }
610 }
611 }
612 return NULL;
613 }
614
615 static void post_class_load_event(EventClassLoad* event,
616 const InstanceKlass* k,
617 const ClassLoaderData* init_cld) {
618 #if INCLUDE_TRACE
619 assert(event != NULL, "invariant");
620 assert(k != NULL, "invariant");
621 if (event->should_commit()) {
622 event->set_loadedClass(k);
623 event->set_definingClassLoader(k->class_loader_data());
624 event->set_initiatingClassLoader(init_cld);
625 event->commit();
626 }
627 #endif // INCLUDE_TRACE
628 }
629
630 static void class_define_event(InstanceKlass* k,
631 const ClassLoaderData* def_cld) {
632 #if INCLUDE_TRACE
633 EventClassDefine event;
634 if (event.should_commit()) {
635 event.set_definedClass(k);
636 event.set_definingClassLoader(def_cld);
637 event.commit();
638 }
639 #endif // INCLUDE_TRACE
640 }
641
642 // Be careful when modifying this code: once you have run
643 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
644 // you need to find_and_remove it before returning.
645 // So be careful to not exit with a CHECK_ macro betweeen these calls.
646 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
647 Handle class_loader,
648 Handle protection_domain,
649 TRAPS) {
650 assert(name != NULL && !FieldType::is_array(name) &&
651 !FieldType::is_obj(name), "invalid class name");
652
653 EventClassLoad class_load_start_event;
654
655 HandleMark hm(THREAD);
656
657 // Fix for 4474172; see evaluation for more details
658 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
659 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
660 Dictionary* dictionary = loader_data->dictionary();
661
662 // Do lookup to see if class already exist and the protection domain
663 // has the right access
664 // This call uses find which checks protection domain already matches
665 // All subsequent calls use find_class, and set has_loaded_class so that
666 // before we return a result we call out to java to check for valid protection domain
667 // to allow returning the Klass* and add it to the pd_set if it is valid
668 unsigned int d_hash = dictionary->compute_hash(name);
669 int d_index = dictionary->hash_to_index(d_hash);
670 Klass* probe = dictionary->find(d_index, d_hash, name, protection_domain);
671 if (probe != NULL) return probe;
672
673
674 // Non-bootstrap class loaders will call out to class loader and
675 // define via jvm/jni_DefineClass which will acquire the
676 // class loader object lock to protect against multiple threads
677 // defining the class in parallel by accident.
678 // This lock must be acquired here so the waiter will find
679 // any successful result in the SystemDictionary and not attempt
680 // the define
681 // ParallelCapable Classloaders and the bootstrap classloader,
682 // or all classloaders with UnsyncloadClass do not acquire lock here
683 bool DoObjectLock = true;
684 if (is_parallelCapable(class_loader)) {
685 DoObjectLock = false;
686 }
687
688 unsigned int p_hash = placeholders()->compute_hash(name);
689 int p_index = placeholders()->hash_to_index(p_hash);
690
691 // Class is not in SystemDictionary so we have to do loading.
692 // Make sure we are synchronized on the class loader before we proceed
693 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
694 check_loader_lock_contention(lockObject, THREAD);
695 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
696
697 // Check again (after locking) if class already exist in SystemDictionary
698 bool class_has_been_loaded = false;
699 bool super_load_in_progress = false;
700 bool havesupername = false;
701 InstanceKlass* k = NULL;
702 PlaceholderEntry* placeholder;
703 Symbol* superclassname = NULL;
704
705 {
706 MutexLocker mu(SystemDictionary_lock, THREAD);
707 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
708 if (check != NULL) {
709 // Klass is already loaded, so just return it
710 class_has_been_loaded = true;
711 k = check;
712 } else {
713 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
714 if (placeholder && placeholder->super_load_in_progress()) {
715 super_load_in_progress = true;
716 if (placeholder->havesupername() == true) {
717 superclassname = placeholder->supername();
718 havesupername = true;
719 }
720 }
721 }
722 }
723
724 // If the class is in the placeholder table, class loading is in progress
725 if (super_load_in_progress && havesupername==true) {
726 k = handle_parallel_super_load(name,
727 superclassname,
728 class_loader,
729 protection_domain,
730 lockObject, THREAD);
731 if (HAS_PENDING_EXCEPTION) {
732 return NULL;
733 }
734 if (k != NULL) {
735 class_has_been_loaded = true;
736 }
737 }
738
739 bool throw_circularity_error = false;
740 if (!class_has_been_loaded) {
741 bool load_instance_added = false;
742
743 // add placeholder entry to record loading instance class
744 // Five cases:
745 // All cases need to prevent modifying bootclasssearchpath
746 // in parallel with a classload of same classname
747 // Redefineclasses uses existence of the placeholder for the duration
748 // of the class load to prevent concurrent redefinition of not completely
749 // defined classes.
750 // case 1. traditional classloaders that rely on the classloader object lock
751 // - no other need for LOAD_INSTANCE
752 // case 2. traditional classloaders that break the classloader object lock
753 // as a deadlock workaround. Detection of this case requires that
754 // this check is done while holding the classloader object lock,
755 // and that lock is still held when calling classloader's loadClass.
756 // For these classloaders, we ensure that the first requestor
757 // completes the load and other requestors wait for completion.
758 // case 3. UnsyncloadClass - don't use objectLocker
759 // With this flag, we allow parallel classloading of a
760 // class/classloader pair
761 // case4. Bootstrap classloader - don't own objectLocker
762 // This classloader supports parallelism at the classloader level,
763 // but only allows a single load of a class/classloader pair.
764 // No performance benefit and no deadlock issues.
765 // case 5. parallelCapable user level classloaders - without objectLocker
766 // Allow parallel classloading of a class/classloader pair
767
768 {
769 MutexLocker mu(SystemDictionary_lock, THREAD);
770 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
771 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
772 if (oldprobe) {
773 // only need check_seen_thread once, not on each loop
774 // 6341374 java/lang/Instrument with -Xcomp
775 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
776 throw_circularity_error = true;
777 } else {
778 // case 1: traditional: should never see load_in_progress.
779 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
780
781 // case 4: bootstrap classloader: prevent futile classloading,
782 // wait on first requestor
783 if (class_loader.is_null()) {
784 SystemDictionary_lock->wait();
785 } else {
786 // case 2: traditional with broken classloader lock. wait on first
787 // requestor.
788 double_lock_wait(lockObject, THREAD);
789 }
790 // Check if classloading completed while we were waiting
791 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
792 if (check != NULL) {
793 // Klass is already loaded, so just return it
794 k = check;
795 class_has_been_loaded = true;
796 }
797 // check if other thread failed to load and cleaned up
798 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
799 }
800 }
801 }
802 }
803 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
804 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
805 // LOAD_INSTANCE in parallel
806
807 if (!throw_circularity_error && !class_has_been_loaded) {
808 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
809 load_instance_added = true;
810 // For class loaders that do not acquire the classloader object lock,
811 // if they did not catch another thread holding LOAD_INSTANCE,
812 // need a check analogous to the acquire ObjectLocker/find_class
813 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
814 // one final check if the load has already completed
815 // class loaders holding the ObjectLock shouldn't find the class here
816 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
817 if (check != NULL) {
818 // Klass is already loaded, so return it after checking/adding protection domain
819 k = check;
820 class_has_been_loaded = true;
821 }
822 }
823 }
824
825 // must throw error outside of owning lock
826 if (throw_circularity_error) {
827 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
828 ResourceMark rm(THREAD);
829 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
830 }
831
832 if (!class_has_been_loaded) {
833
834 // Do actual loading
835 k = load_instance_class(name, class_loader, THREAD);
836
837 // For UnsyncloadClass only
838 // If they got a linkageError, check if a parallel class load succeeded.
839 // If it did, then for bytecode resolution the specification requires
840 // that we return the same result we did for the other thread, i.e. the
841 // successfully loaded InstanceKlass
842 // Should not get here for classloaders that support parallelism
843 // with the new cleaner mechanism, even with AllowParallelDefineClass
844 // Bootstrap goes through here to allow for an extra guarantee check
845 if (UnsyncloadClass || (class_loader.is_null())) {
846 if (k == NULL && HAS_PENDING_EXCEPTION
847 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
848 MutexLocker mu(SystemDictionary_lock, THREAD);
849 InstanceKlass* check = find_class(d_index, d_hash, name, dictionary);
850 if (check != NULL) {
851 // Klass is already loaded, so just use it
852 k = check;
853 CLEAR_PENDING_EXCEPTION;
854 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
855 }
856 }
857 }
858
859 // If everything was OK (no exceptions, no null return value), and
860 // class_loader is NOT the defining loader, do a little more bookkeeping.
861 if (!HAS_PENDING_EXCEPTION && k != NULL &&
862 k->class_loader() != class_loader()) {
863
864 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
865
866 // Need to check for a PENDING_EXCEPTION again; check_constraints
867 // can throw and doesn't use the CHECK macro.
868 if (!HAS_PENDING_EXCEPTION) {
869 { // Grabbing the Compile_lock prevents systemDictionary updates
870 // during compilations.
871 MutexLocker mu(Compile_lock, THREAD);
872 update_dictionary(d_index, d_hash, p_index, p_hash,
873 k, class_loader, THREAD);
874 }
875
876 if (JvmtiExport::should_post_class_load()) {
877 Thread *thread = THREAD;
878 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
879 JvmtiExport::post_class_load((JavaThread *) thread, k);
880 }
881 }
882 }
883 } // load_instance_class
884
885 if (load_instance_added == true) {
886 // clean up placeholder entries for LOAD_INSTANCE success or error
887 // This brackets the SystemDictionary updates for both defining
888 // and initiating loaders
889 MutexLocker mu(SystemDictionary_lock, THREAD);
890 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
891 SystemDictionary_lock->notify_all();
892 }
893 }
894
895 if (HAS_PENDING_EXCEPTION || k == NULL) {
896 return NULL;
897 }
898
899 post_class_load_event(&class_load_start_event, k, loader_data);
900
901 #ifdef ASSERT
902 {
903 ClassLoaderData* loader_data = k->class_loader_data();
904 MutexLocker mu(SystemDictionary_lock, THREAD);
905 Klass* kk = find_class(name, loader_data);
906 assert(kk == k, "should be present in dictionary");
907 }
908 #endif
909
910 // return if the protection domain in NULL
911 if (protection_domain() == NULL) return k;
912
913 // Check the protection domain has the right access
914 if (dictionary->is_valid_protection_domain(d_index, d_hash, name,
915 protection_domain)) {
916 return k;
917 }
918
919 // Verify protection domain. If it fails an exception is thrown
920 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
921
922 return k;
923 }
924
925
926 // This routine does not lock the system dictionary.
927 //
928 // Since readers don't hold a lock, we must make sure that system
929 // dictionary entries are only removed at a safepoint (when only one
930 // thread is running), and are added to in a safe way (all links must
931 // be updated in an MT-safe manner).
932 //
933 // Callers should be aware that an entry could be added just after
934 // _dictionary->bucket(index) is read here, so the caller will not see
935 // the new entry.
936
937 Klass* SystemDictionary::find(Symbol* class_name,
938 Handle class_loader,
939 Handle protection_domain,
940 TRAPS) {
941
942 // The result of this call should be consistent with the result
943 // of the call to resolve_instance_class_or_null().
944 // See evaluation 6790209 and 4474172 for more details.
945 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
946 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
947
948 if (loader_data == NULL) {
949 // If the ClassLoaderData has not been setup,
950 // then the class loader has no entries in the dictionary.
951 return NULL;
952 }
953
954 Dictionary* dictionary = loader_data->dictionary();
955 unsigned int d_hash = dictionary->compute_hash(class_name);
956 int d_index = dictionary->hash_to_index(d_hash);
957 return dictionary->find(d_index, d_hash, class_name,
958 protection_domain);
959 }
960
961
962 // Look for a loaded instance or array klass by name. Do not do any loading.
963 // return NULL in case of error.
964 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
965 Handle class_loader,
966 Handle protection_domain,
967 TRAPS) {
968 Klass* k = NULL;
969 assert(class_name != NULL, "class name must be non NULL");
970
971 if (FieldType::is_array(class_name)) {
972 // The name refers to an array. Parse the name.
973 // dimension and object_key in FieldArrayInfo are assigned as a
974 // side-effect of this call
975 FieldArrayInfo fd;
976 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
977 if (t != T_OBJECT) {
978 k = Universe::typeArrayKlassObj(t);
979 } else {
980 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
981 }
982 if (k != NULL) {
983 k = k->array_klass_or_null(fd.dimension());
984 }
985 } else {
986 k = find(class_name, class_loader, protection_domain, THREAD);
987 }
988 return k;
989 }
990
991 // Note: this method is much like resolve_from_stream, but
992 // does not publish the classes via the SystemDictionary.
993 // Handles unsafe_DefineAnonymousClass and redefineclasses
994 // RedefinedClasses do not add to the class hierarchy
995 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
996 Handle class_loader,
997 Handle protection_domain,
998 ClassFileStream* st,
999 const InstanceKlass* host_klass,
1000 GrowableArray<Handle>* cp_patches,
1001 TRAPS) {
1002
1003 EventClassLoad class_load_start_event;
1004
1005 ClassLoaderData* loader_data;
1006 if (host_klass != NULL) {
1007 // Create a new CLD for anonymous class, that uses the same class loader
1008 // as the host_klass
1009 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1010 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1011 } else {
1012 loader_data = ClassLoaderData::class_loader_data(class_loader());
1013 }
1014
1015 assert(st != NULL, "invariant");
1016 assert(st->need_verify(), "invariant");
1017
1018 // Parse stream and create a klass.
1019 // Note that we do this even though this klass might
1020 // already be present in the SystemDictionary, otherwise we would not
1021 // throw potential ClassFormatErrors.
1022
1023 InstanceKlass* k = KlassFactory::create_from_stream(st,
1024 class_name,
1025 loader_data,
1026 protection_domain,
1027 host_klass,
1028 cp_patches,
1029 CHECK_NULL);
1030
1031 if (host_klass != NULL && k != NULL) {
1032 // If it's anonymous, initialize it now, since nobody else will.
1033
1034 {
1035 MutexLocker mu_r(Compile_lock, THREAD);
1036
1037 // Add to class hierarchy, initialize vtables, and do possible
1038 // deoptimizations.
1039 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1040
1041 // But, do not add to dictionary.
1042
1043 // compiled code dependencies need to be validated anyway
1044 notice_modification();
1045 }
1046
1047 // Rewrite and patch constant pool here.
1048 k->link_class(CHECK_NULL);
1049 if (cp_patches != NULL) {
1050 k->constants()->patch_resolved_references(cp_patches);
1051 }
1052 k->eager_initialize(CHECK_NULL);
1053
1054 // notify jvmti
1055 if (JvmtiExport::should_post_class_load()) {
1056 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1057 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1058 }
1059
1060 post_class_load_event(&class_load_start_event, k, loader_data);
1061 }
1062 assert(host_klass != NULL || NULL == cp_patches,
1063 "cp_patches only found with host_klass");
1064
1065 return k;
1066 }
1067
1068 // Add a klass to the system from a stream (called by jni_DefineClass and
1069 // JVM_DefineClass).
1070 // Note: class_name can be NULL. In that case we do not know the name of
1071 // the class until we have parsed the stream.
1072
1073 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1074 Handle class_loader,
1075 Handle protection_domain,
1076 ClassFileStream* st,
1077 TRAPS) {
1078 #if INCLUDE_CDS
1079 ResourceMark rm(THREAD);
1080 if (DumpSharedSpaces && !class_loader.is_null() &&
1081 !ArgumentsExt::using_AppCDS() && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1082 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1083 // class, which is used by MethodHandles).
1084 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1085 }
1086 #endif
1087
1088 HandleMark hm(THREAD);
1089
1090 // Classloaders that support parallelism, e.g. bootstrap classloader,
1091 // or all classloaders with UnsyncloadClass do not acquire lock here
1092 bool DoObjectLock = true;
1093 if (is_parallelCapable(class_loader)) {
1094 DoObjectLock = false;
1095 }
1096
1097 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1098
1099 // Make sure we are synchronized on the class loader before we proceed
1100 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1101 check_loader_lock_contention(lockObject, THREAD);
1102 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1103
1104 assert(st != NULL, "invariant");
1105
1106 // Parse the stream and create a klass.
1107 // Note that we do this even though this klass might
1108 // already be present in the SystemDictionary, otherwise we would not
1109 // throw potential ClassFormatErrors.
1110 InstanceKlass* k = NULL;
1111
1112 #if INCLUDE_CDS
1113 if (!DumpSharedSpaces) {
1114 k = SystemDictionaryShared::lookup_from_stream(class_name,
1115 class_loader,
1116 protection_domain,
1117 st,
1118 CHECK_NULL);
1119 }
1120 #endif
1121
1122 if (k == NULL) {
1123 if (st->buffer() == NULL) {
1124 return NULL;
1125 }
1126 k = KlassFactory::create_from_stream(st,
1127 class_name,
1128 loader_data,
1129 protection_domain,
1130 NULL, // host_klass
1131 NULL, // cp_patches
1132 CHECK_NULL);
1133 }
1134
1135 assert(k != NULL, "no klass created");
1136 Symbol* h_name = k->name();
1137 assert(class_name == NULL || class_name == h_name, "name mismatch");
1138
1139 // Add class just loaded
1140 // If a class loader supports parallel classloading handle parallel define requests
1141 // find_or_define_instance_class may return a different InstanceKlass
1142 if (is_parallelCapable(class_loader)) {
1143 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1144 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1145 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1146 assert(defined_k != NULL, "Should have a klass if there's no exception");
1147 loader_data->add_to_deallocate_list(k);
1148 k = defined_k;
1149 }
1150 } else {
1151 define_instance_class(k, THREAD);
1152 }
1153
1154 // If defining the class throws an exception register 'k' for cleanup.
1155 if (HAS_PENDING_EXCEPTION) {
1156 assert(k != NULL, "Must have an instance klass here!");
1157 loader_data->add_to_deallocate_list(k);
1158 return NULL;
1159 }
1160
1161 // Make sure we have an entry in the SystemDictionary on success
1162 debug_only( {
1163 MutexLocker mu(SystemDictionary_lock, THREAD);
1164
1165 Klass* check = find_class(h_name, k->class_loader_data());
1166 assert(check == k, "should be present in the dictionary");
1167 } );
1168
1169 return k;
1170 }
1171
1172 #if INCLUDE_CDS
1173 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1174 int number_of_entries) {
1175 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1176 "bad shared dictionary size.");
1177 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1178 _shared_dictionary_size, t, number_of_entries);
1179 }
1180
1181
1182 // If there is a shared dictionary, then find the entry for the
1183 // given shared system class, if any.
1184
1185 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1186 if (shared_dictionary() != NULL) {
1187 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1188 int d_index = shared_dictionary()->hash_to_index(d_hash);
1189
1190 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1191 } else {
1192 return NULL;
1193 }
1194 }
1195
1196
1197 // Load a class from the shared spaces (found through the shared system
1198 // dictionary). Force the superclass and all interfaces to be loaded.
1199 // Update the class definition to include sibling classes and no
1200 // subclasses (yet). [Classes in the shared space are not part of the
1201 // object hierarchy until loaded.]
1202
1203 InstanceKlass* SystemDictionary::load_shared_class(
1204 Symbol* class_name, Handle class_loader, TRAPS) {
1205 InstanceKlass* ik = find_shared_class(class_name);
1206 // Make sure we only return the boot class for the NULL classloader.
1207 if (ik != NULL &&
1208 ik->is_shared_boot_class() && class_loader.is_null()) {
1209 Handle protection_domain;
1210 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1211 }
1212 return NULL;
1213 }
1214
1215 // Check if a shared class can be loaded by the specific classloader:
1216 //
1217 // NULL classloader:
1218 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1219 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1220 // be defined in an unnamed module.
1221 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1222 InstanceKlass* ik,
1223 Handle class_loader, TRAPS) {
1224 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1225 "Cannot use sharing if java.base is patched");
1226 ResourceMark rm;
1227 int path_index = ik->shared_classpath_index();
1228 ClassLoaderData* loader_data = class_loader_data(class_loader);
1229 if (path_index < 0) {
1230 // path_index < 0 indicates that the class is intended for a custom loader
1231 // and should not be loaded by boot/platform/app loaders
1232 if (loader_data->is_builtin_class_loader_data()) {
1233 return false;
1234 } else {
1235 return true;
1236 }
1237 }
1238 SharedClassPathEntry* ent =
1239 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1240 if (!Universe::is_module_initialized()) {
1241 assert(ent != NULL && ent->is_jrt(),
1242 "Loading non-bootstrap classes before the module system is initialized");
1243 assert(class_loader.is_null(), "sanity");
1244 return true;
1245 }
1246 // Get the pkg_entry from the classloader
1247 TempNewSymbol pkg_name = NULL;
1248 PackageEntry* pkg_entry = NULL;
1249 ModuleEntry* mod_entry = NULL;
1250 const char* pkg_string = NULL;
1251 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1252 if (pkg_name != NULL) {
1253 pkg_string = pkg_name->as_C_string();
1254 if (loader_data != NULL) {
1255 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1256 }
1257 if (pkg_entry != NULL) {
1258 mod_entry = pkg_entry->module();
1259 }
1260 }
1261
1262 // If the archived class is from a module that has been patched at runtime,
1263 // the class cannot be loaded from the archive.
1264 if (mod_entry != NULL && mod_entry->is_patched()) {
1265 return false;
1266 }
1267
1268 if (class_loader.is_null()) {
1269 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1270 // The NULL classloader can load archived class originated from the
1271 // "modules" jimage and the -Xbootclasspath/a. For class from the
1272 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1273 // by the NULL classloader.
1274 if (mod_entry != NULL) {
1275 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1276 // ModuleEntry's location agrees with the archived class' origination.
1277 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1278 return true; // Module class from the "module" jimage
1279 }
1280 }
1281
1282 // If the archived class is not from the "module" jimage, the class can be
1283 // loaded by the NULL classloader if
1284 //
1285 // 1. the class is from the unamed package
1286 // 2. or, the class is not from a module defined in the NULL classloader
1287 // 3. or, the class is from an unamed module
1288 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1289 // the class is from the -Xbootclasspath/a
1290 if (pkg_string == NULL ||
1291 pkg_entry == NULL ||
1292 pkg_entry->in_unnamed_module()) {
1293 assert(mod_entry == NULL ||
1294 mod_entry == loader_data->unnamed_module(),
1295 "the unnamed module is not defined in the classloader");
1296 return true;
1297 }
1298 }
1299 return false;
1300 } else {
1301 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1302 ik, class_loader, pkg_string, pkg_name,
1303 pkg_entry, mod_entry, CHECK_(false));
1304 return res;
1305 }
1306 }
1307
1308 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1309 Handle class_loader,
1310 Handle protection_domain, TRAPS) {
1311
1312 if (ik != NULL) {
1313 Symbol* class_name = ik->name();
1314
1315 bool visible = is_shared_class_visible(
1316 class_name, ik, class_loader, CHECK_NULL);
1317 if (!visible) {
1318 return NULL;
1319 }
1320
1321 // Resolve the superclass and interfaces. They must be the same
1322 // as in dump time, because the layout of <ik> depends on
1323 // the specific layout of ik->super() and ik->local_interfaces().
1324 //
1325 // If unexpected superclass or interfaces are found, we cannot
1326 // load <ik> from the shared archive.
1327
1328 if (ik->super() != NULL) {
1329 Symbol* cn = ik->super()->name();
1330 Klass *s = resolve_super_or_fail(class_name, cn,
1331 class_loader, protection_domain, true, CHECK_NULL);
1332 if (s != ik->super()) {
1333 // The dynamically resolved super class is not the same as the one we used during dump time,
1334 // so we cannot use ik.
1335 return NULL;
1336 } else {
1337 assert(s->is_shared(), "must be");
1338 }
1339 }
1340
1341 Array<Klass*>* interfaces = ik->local_interfaces();
1342 int num_interfaces = interfaces->length();
1343 for (int index = 0; index < num_interfaces; index++) {
1344 Klass* k = interfaces->at(index);
1345 Symbol* name = k->name();
1346 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1347 if (k != i) {
1348 // The dynamically resolved interface class is not the same as the one we used during dump time,
1349 // so we cannot use ik.
1350 return NULL;
1351 } else {
1352 assert(i->is_shared(), "must be");
1353 }
1354 }
1355
1356 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1357 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1358 if (new_ik != NULL) {
1359 // The class is changed by CFLH. Return the new class. The shared class is
1360 // not used.
1361 return new_ik;
1362 }
1363
1364 // Adjust methods to recover missing data. They need addresses for
1365 // interpreter entry points and their default native method address
1366 // must be reset.
1367
1368 // Updating methods must be done under a lock so multiple
1369 // threads don't update these in parallel
1370 //
1371 // Shared classes are all currently loaded by either the bootstrap or
1372 // internal parallel class loaders, so this will never cause a deadlock
1373 // on a custom class loader lock.
1374
1375 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1376 {
1377 HandleMark hm(THREAD);
1378 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1379 check_loader_lock_contention(lockObject, THREAD);
1380 ObjectLocker ol(lockObject, THREAD, true);
1381 // prohibited package check assumes all classes loaded from archive call
1382 // restore_unshareable_info which calls ik->set_package()
1383 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1384 }
1385
1386 ik->print_class_load_logging(loader_data, NULL, NULL);
1387
1388 // For boot loader, ensure that GetSystemPackage knows that a class in this
1389 // package was loaded.
1390 if (class_loader.is_null()) {
1391 int path_index = ik->shared_classpath_index();
1392 ResourceMark rm;
1393 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1394 }
1395
1396 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1397 // Only dump the classes that can be stored into CDS archive
1398 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1399 ResourceMark rm(THREAD);
1400 classlist_file->print_cr("%s", ik->name()->as_C_string());
1401 classlist_file->flush();
1402 }
1403 }
1404
1405 // notify a class loaded from shared object
1406 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1407 }
1408
1409 ik->set_has_passed_fingerprint_check(false);
1410 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1411 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1412 uint64_t cds_fp = ik->get_stored_fingerprint();
1413 if (aot_fp != 0 && aot_fp == cds_fp) {
1414 // This class matches with a class saved in an AOT library
1415 ik->set_has_passed_fingerprint_check(true);
1416 } else {
1417 ResourceMark rm;
1418 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1419 }
1420 }
1421 return ik;
1422 }
1423
1424 void SystemDictionary::clear_invoke_method_table() {
1425 SymbolPropertyEntry* spe = NULL;
1426 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1427 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1428 while (p != NULL) {
1429 spe = p;
1430 p = p->next();
1431 _invoke_method_table->free_entry(spe);
1432 }
1433 }
1434 }
1435 #endif // INCLUDE_CDS
1436
1437 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1438
1439 if (class_loader.is_null()) {
1440 ResourceMark rm;
1441 PackageEntry* pkg_entry = NULL;
1442 bool search_only_bootloader_append = false;
1443 ClassLoaderData *loader_data = class_loader_data(class_loader);
1444
1445 // Find the package in the boot loader's package entry table.
1446 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1447 if (pkg_name != NULL) {
1448 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1449 }
1450
1451 // Prior to attempting to load the class, enforce the boot loader's
1452 // visibility boundaries.
1453 if (!Universe::is_module_initialized()) {
1454 // During bootstrapping, prior to module initialization, any
1455 // class attempting to be loaded must be checked against the
1456 // java.base packages in the boot loader's PackageEntryTable.
1457 // No class outside of java.base is allowed to be loaded during
1458 // this bootstrapping window.
1459 if (!DumpSharedSpaces) {
1460 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1461 // Class is either in the unnamed package or in
1462 // a named package within the unnamed module. Either
1463 // case is outside of java.base, do not attempt to
1464 // load the class post java.base definition. If
1465 // java.base has not been defined, let the class load
1466 // and its package will be checked later by
1467 // ModuleEntryTable::verify_javabase_packages.
1468 if (ModuleEntryTable::javabase_defined()) {
1469 return NULL;
1470 }
1471 } else {
1472 // Check that the class' package is defined within java.base.
1473 ModuleEntry* mod_entry = pkg_entry->module();
1474 Symbol* mod_entry_name = mod_entry->name();
1475 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1476 return NULL;
1477 }
1478 }
1479 }
1480 } else {
1481 // After the module system has been initialized, check if the class'
1482 // package is in a module defined to the boot loader.
1483 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1484 // Class is either in the unnamed package, in a named package
1485 // within a module not defined to the boot loader or in a
1486 // a named package within the unnamed module. In all cases,
1487 // limit visibility to search for the class only in the boot
1488 // loader's append path.
1489 search_only_bootloader_append = true;
1490 }
1491 }
1492
1493 // Prior to bootstrapping's module initialization, never load a class outside
1494 // of the boot loader's module path
1495 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1496 !search_only_bootloader_append,
1497 "Attempt to load a class outside of boot loader's module path");
1498
1499 // Search the shared system dictionary for classes preloaded into the
1500 // shared spaces.
1501 InstanceKlass* k = NULL;
1502 {
1503 #if INCLUDE_CDS
1504 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1505 k = load_shared_class(class_name, class_loader, THREAD);
1506 #endif
1507 }
1508
1509 if (k == NULL) {
1510 // Use VM class loader
1511 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1512 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1513 }
1514
1515 // find_or_define_instance_class may return a different InstanceKlass
1516 if (k != NULL) {
1517 InstanceKlass* defined_k =
1518 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1519 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1520 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1521 assert(defined_k != NULL, "Should have a klass if there's no exception");
1522 loader_data->add_to_deallocate_list(k);
1523 k = defined_k;
1524 } else if (HAS_PENDING_EXCEPTION) {
1525 loader_data->add_to_deallocate_list(k);
1526 return NULL;
1527 }
1528 }
1529 return k;
1530 } else {
1531 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1532 ResourceMark rm(THREAD);
1533
1534 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1535 JavaThread* jt = (JavaThread*) THREAD;
1536
1537 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1538 ClassLoader::perf_app_classload_selftime(),
1539 ClassLoader::perf_app_classload_count(),
1540 jt->get_thread_stat()->perf_recursion_counts_addr(),
1541 jt->get_thread_stat()->perf_timers_addr(),
1542 PerfClassTraceTime::CLASS_LOAD);
1543
1544 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1545 // Translate to external class name format, i.e., convert '/' chars to '.'
1546 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1547
1548 JavaValue result(T_OBJECT);
1549
1550 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1551
1552 // Call public unsynchronized loadClass(String) directly for all class loaders
1553 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1554 // acquire a class-name based lock rather than the class loader object lock.
1555 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1556 // so the call to loadClassInternal() was not required.
1557 //
1558 // UnsyncloadClass flag means both call loadClass(String) and do
1559 // not acquire the class loader lock even for class loaders that are
1560 // not parallelCapable. This was a risky transitional
1561 // flag for diagnostic purposes only. It is risky to call
1562 // custom class loaders without synchronization.
1563 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1564 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1565 // Do NOT assume this will be supported in future releases.
1566 //
1567 // Added MustCallLoadClassInternal in case we discover in the field
1568 // a customer that counts on this call
1569 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1570 JavaCalls::call_special(&result,
1571 class_loader,
1572 spec_klass,
1573 vmSymbols::loadClassInternal_name(),
1574 vmSymbols::string_class_signature(),
1575 string,
1576 CHECK_NULL);
1577 } else {
1578 JavaCalls::call_virtual(&result,
1579 class_loader,
1580 spec_klass,
1581 vmSymbols::loadClass_name(),
1582 vmSymbols::string_class_signature(),
1583 string,
1584 CHECK_NULL);
1585 }
1586
1587 assert(result.get_type() == T_OBJECT, "just checking");
1588 oop obj = (oop) result.get_jobject();
1589
1590 // Primitive classes return null since forName() can not be
1591 // used to obtain any of the Class objects representing primitives or void
1592 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1593 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1594 // For user defined Java class loaders, check that the name returned is
1595 // the same as that requested. This check is done for the bootstrap
1596 // loader when parsing the class file.
1597 if (class_name == k->name()) {
1598 return k;
1599 }
1600 }
1601 // Class is not found or has the wrong name, return NULL
1602 return NULL;
1603 }
1604 }
1605
1606 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1607
1608 HandleMark hm(THREAD);
1609 ClassLoaderData* loader_data = k->class_loader_data();
1610 Handle class_loader_h(THREAD, loader_data->class_loader());
1611
1612 // for bootstrap and other parallel classloaders don't acquire lock,
1613 // use placeholder token
1614 // If a parallelCapable class loader calls define_instance_class instead of
1615 // find_or_define_instance_class to get here, we have a timing
1616 // hole with systemDictionary updates and check_constraints
1617 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1618 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1619 compute_loader_lock_object(class_loader_h, THREAD)),
1620 "define called without lock");
1621 }
1622
1623 // Check class-loading constraints. Throw exception if violation is detected.
1624 // Grabs and releases SystemDictionary_lock
1625 // The check_constraints/find_class call and update_dictionary sequence
1626 // must be "atomic" for a specific class/classloader pair so we never
1627 // define two different instanceKlasses for that class/classloader pair.
1628 // Existing classloaders will call define_instance_class with the
1629 // classloader lock held
1630 // Parallel classloaders will call find_or_define_instance_class
1631 // which will require a token to perform the define class
1632 Symbol* name_h = k->name();
1633 Dictionary* dictionary = loader_data->dictionary();
1634 unsigned int d_hash = dictionary->compute_hash(name_h);
1635 int d_index = dictionary->hash_to_index(d_hash);
1636 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1637
1638 // Register class just loaded with class loader (placed in Vector)
1639 // Note we do this before updating the dictionary, as this can
1640 // fail with an OutOfMemoryError (if it does, we will *not* put this
1641 // class in the dictionary and will not update the class hierarchy).
1642 // JVMTI FollowReferences needs to find the classes this way.
1643 if (k->class_loader() != NULL) {
1644 methodHandle m(THREAD, Universe::loader_addClass_method());
1645 JavaValue result(T_VOID);
1646 JavaCallArguments args(class_loader_h);
1647 args.push_oop(Handle(THREAD, k->java_mirror()));
1648 JavaCalls::call(&result, m, &args, CHECK);
1649 }
1650
1651 // Add the new class. We need recompile lock during update of CHA.
1652 {
1653 unsigned int p_hash = placeholders()->compute_hash(name_h);
1654 int p_index = placeholders()->hash_to_index(p_hash);
1655
1656 MutexLocker mu_r(Compile_lock, THREAD);
1657
1658 // Add to class hierarchy, initialize vtables, and do possible
1659 // deoptimizations.
1660 add_to_hierarchy(k, CHECK); // No exception, but can block
1661
1662 // Add to systemDictionary - so other classes can see it.
1663 // Grabs and releases SystemDictionary_lock
1664 update_dictionary(d_index, d_hash, p_index, p_hash,
1665 k, class_loader_h, THREAD);
1666 }
1667 k->eager_initialize(THREAD);
1668
1669 // notify jvmti
1670 if (JvmtiExport::should_post_class_load()) {
1671 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1672 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1673
1674 }
1675 class_define_event(k, loader_data);
1676 }
1677
1678 // Support parallel classloading
1679 // All parallel class loaders, including bootstrap classloader
1680 // lock a placeholder entry for this class/class_loader pair
1681 // to allow parallel defines of different classes for this class loader
1682 // With AllowParallelDefine flag==true, in case they do not synchronize around
1683 // FindLoadedClass/DefineClass, calls, we check for parallel
1684 // loading for them, wait if a defineClass is in progress
1685 // and return the initial requestor's results
1686 // This flag does not apply to the bootstrap classloader.
1687 // With AllowParallelDefine flag==false, call through to define_instance_class
1688 // which will throw LinkageError: duplicate class definition.
1689 // False is the requested default.
1690 // For better performance, the class loaders should synchronize
1691 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1692 // potentially waste time reading and parsing the bytestream.
1693 // Note: VM callers should ensure consistency of k/class_name,class_loader
1694 // Be careful when modifying this code: once you have run
1695 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1696 // you need to find_and_remove it before returning.
1697 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1698 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1699 InstanceKlass* k, TRAPS) {
1700
1701 Symbol* name_h = k->name(); // passed in class_name may be null
1702 ClassLoaderData* loader_data = class_loader_data(class_loader);
1703 Dictionary* dictionary = loader_data->dictionary();
1704
1705 unsigned int d_hash = dictionary->compute_hash(name_h);
1706 int d_index = dictionary->hash_to_index(d_hash);
1707
1708 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1709 unsigned int p_hash = placeholders()->compute_hash(name_h);
1710 int p_index = placeholders()->hash_to_index(p_hash);
1711 PlaceholderEntry* probe;
1712
1713 {
1714 MutexLocker mu(SystemDictionary_lock, THREAD);
1715 // First check if class already defined
1716 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1717 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1718 if (check != NULL) {
1719 return check;
1720 }
1721 }
1722
1723 // Acquire define token for this class/classloader
1724 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1725 // Wait if another thread defining in parallel
1726 // All threads wait - even those that will throw duplicate class: otherwise
1727 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1728 // if other thread has not finished updating dictionary
1729 while (probe->definer() != NULL) {
1730 SystemDictionary_lock->wait();
1731 }
1732 // Only special cases allow parallel defines and can use other thread's results
1733 // Other cases fall through, and may run into duplicate defines
1734 // caught by finding an entry in the SystemDictionary
1735 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1736 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1737 SystemDictionary_lock->notify_all();
1738 #ifdef ASSERT
1739 InstanceKlass* check = find_class(d_index, d_hash, name_h, dictionary);
1740 assert(check != NULL, "definer missed recording success");
1741 #endif
1742 return probe->instance_klass();
1743 } else {
1744 // This thread will define the class (even if earlier thread tried and had an error)
1745 probe->set_definer(THREAD);
1746 }
1747 }
1748
1749 define_instance_class(k, THREAD);
1750
1751 Handle linkage_exception = Handle(); // null handle
1752
1753 // definer must notify any waiting threads
1754 {
1755 MutexLocker mu(SystemDictionary_lock, THREAD);
1756 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1757 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1758 if (probe != NULL) {
1759 if (HAS_PENDING_EXCEPTION) {
1760 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1761 CLEAR_PENDING_EXCEPTION;
1762 } else {
1763 probe->set_instance_klass(k);
1764 }
1765 probe->set_definer(NULL);
1766 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1767 SystemDictionary_lock->notify_all();
1768 }
1769 }
1770
1771 // Can't throw exception while holding lock due to rank ordering
1772 if (linkage_exception() != NULL) {
1773 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1774 }
1775
1776 return k;
1777 }
1778
1779 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1780 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1781 if (class_loader.is_null()) {
1782 return Handle(THREAD, _system_loader_lock_obj);
1783 } else {
1784 return class_loader;
1785 }
1786 }
1787
1788 // This method is added to check how often we have to wait to grab loader
1789 // lock. The results are being recorded in the performance counters defined in
1790 // ClassLoader::_sync_systemLoaderLockContentionRate and
1791 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1792 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1793 if (!UsePerfData) {
1794 return;
1795 }
1796
1797 assert(!loader_lock.is_null(), "NULL lock object");
1798
1799 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1800 == ObjectSynchronizer::owner_other) {
1801 // contention will likely happen, so increment the corresponding
1802 // contention counter.
1803 if (loader_lock() == _system_loader_lock_obj) {
1804 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1805 } else {
1806 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1807 }
1808 }
1809 }
1810
1811 // ----------------------------------------------------------------------------
1812 // Lookup
1813
1814 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1815 Symbol* class_name,
1816 Dictionary* dictionary) {
1817 assert_locked_or_safepoint(SystemDictionary_lock);
1818 return dictionary->find_class(index, hash, class_name);
1819 }
1820
1821
1822 // Basic find on classes in the midst of being loaded
1823 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1824 ClassLoaderData* loader_data) {
1825 assert_locked_or_safepoint(SystemDictionary_lock);
1826 unsigned int p_hash = placeholders()->compute_hash(class_name);
1827 int p_index = placeholders()->hash_to_index(p_hash);
1828 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1829 }
1830
1831
1832 // Used for assertions and verification only
1833 // Precalculating the hash and index is an optimization because there are many lookups
1834 // before adding the class.
1835 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1836 assert_locked_or_safepoint(SystemDictionary_lock);
1837 #ifndef ASSERT
1838 guarantee(VerifyBeforeGC ||
1839 VerifyDuringGC ||
1840 VerifyBeforeExit ||
1841 VerifyDuringStartup ||
1842 VerifyAfterGC, "too expensive");
1843 #endif
1844
1845 Dictionary* dictionary = loader_data->dictionary();
1846 unsigned int d_hash = dictionary->compute_hash(class_name);
1847 int d_index = dictionary->hash_to_index(d_hash);
1848 return find_class(d_index, d_hash, class_name, dictionary);
1849 }
1850
1851
1852 // ----------------------------------------------------------------------------
1853 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1854 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1855 // before a new class is used.
1856
1857 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1858 assert(k != NULL, "just checking");
1859 assert_locked_or_safepoint(Compile_lock);
1860
1861 // Link into hierachy. Make sure the vtables are initialized before linking into
1862 k->append_to_sibling_list(); // add to superklass/sibling list
1863 k->process_interfaces(THREAD); // handle all "implements" declarations
1864 k->set_init_state(InstanceKlass::loaded);
1865 // Now flush all code that depended on old class hierarchy.
1866 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1867 // Also, first reinitialize vtable because it may have gotten out of synch
1868 // while the new class wasn't connected to the class hierarchy.
1869 CodeCache::flush_dependents_on(k);
1870 }
1871
1872 // ----------------------------------------------------------------------------
1873 // GC support
1874
1875 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1876 roots_oops_do(blk, NULL);
1877 }
1878
1879
1880 #ifdef ASSERT
1881 class VerifySDReachableAndLiveClosure : public OopClosure {
1882 private:
1883 BoolObjectClosure* _is_alive;
1884
1885 template <class T> void do_oop_work(T* p) {
1886 oop obj = oopDesc::load_decode_heap_oop(p);
1887 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1888 }
1889
1890 public:
1891 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1892
1893 virtual void do_oop(oop* p) { do_oop_work(p); }
1894 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1895 };
1896 #endif
1897
1898 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1899 // Note: anonymous classes are not in the SD.
1900 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1901 GCTimer* gc_timer,
1902 bool do_cleaning) {
1903
1904
1905 bool unloading_occurred;
1906 {
1907 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1908
1909 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1910 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1911 do_cleaning);
1912 }
1913
1914 if (unloading_occurred) {
1915 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1916 constraints()->purge_loader_constraints();
1917 resolution_errors()->purge_resolution_errors();
1918 }
1919
1920 {
1921 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1922 // Oops referenced by the protection domain cache table may get unreachable independently
1923 // of the class loader (eg. cached protection domain oops). So we need to
1924 // explicitly unlink them here.
1925 _pd_cache_table->unlink(is_alive);
1926
1927 #ifdef ASSERT
1928 VerifySDReachableAndLiveClosure cl(is_alive);
1929 _pd_cache_table->oops_do(&cl);
1930 #endif
1931 }
1932
1933 if (do_cleaning) {
1934 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1935 ResolvedMethodTable::unlink(is_alive);
1936 }
1937
1938 return unloading_occurred;
1939 }
1940
1941 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1942 strong->do_oop(&_java_system_loader);
1943 strong->do_oop(&_system_loader_lock_obj);
1944 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1945
1946 // Do strong roots marking if the closures are the same.
1947 if (strong == weak || !ClassUnloading) {
1948 // Only the protection domain oops contain references into the heap. Iterate
1949 // over all of them.
1950 _pd_cache_table->oops_do(strong);
1951 } else {
1952 if (weak != NULL) {
1953 _pd_cache_table->oops_do(weak);
1954 }
1955 }
1956
1957 // Visit extra methods
1958 invoke_method_table()->oops_do(strong);
1959
1960 if (weak != NULL) {
1961 ResolvedMethodTable::oops_do(weak);
1962 }
1963 }
1964
1965 void SystemDictionary::oops_do(OopClosure* f) {
1966 f->do_oop(&_java_system_loader);
1967 f->do_oop(&_system_loader_lock_obj);
1968 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1969
1970 // Only the protection domain oops contain references into the heap. Iterate
1971 // over all of them.
1972 _pd_cache_table->oops_do(f);
1973
1974 // Visit extra methods
1975 invoke_method_table()->oops_do(f);
1976
1977 ResolvedMethodTable::oops_do(f);
1978 }
1979
1980 // CDS: scan and relocate all classes in the system dictionary.
1981 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1982 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1983 }
1984
1985 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1986 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1987 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1988 it->push(well_known_klass_addr((WKID)id));
1989 }
1990 }
1991
1992 void SystemDictionary::methods_do(void f(Method*)) {
1993 // Walk methods in loaded classes
1994 ClassLoaderDataGraph::methods_do(f);
1995 // Walk method handle intrinsics
1996 invoke_method_table()->methods_do(f);
1997 }
1998
1999 class RemoveClassesClosure : public CLDClosure {
2000 public:
2001 void do_cld(ClassLoaderData* cld) {
2002 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2003 cld->dictionary()->remove_classes_in_error_state();
2004 }
2005 }
2006 };
2007
2008 void SystemDictionary::remove_classes_in_error_state() {
2009 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
2010 RemoveClassesClosure rcc;
2011 ClassLoaderDataGraph::cld_do(&rcc);
2012 }
2013
2014 // ----------------------------------------------------------------------------
2015 // Lazily load klasses
2016
2017 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2018 // if multiple threads calling this function, only one thread will load
2019 // the class. The other threads will find the loaded version once the
2020 // class is loaded.
2021 Klass* aos = _abstract_ownable_synchronizer_klass;
2022 if (aos == NULL) {
2023 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2024 // Force a fence to prevent any read before the write completes
2025 OrderAccess::fence();
2026 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2027 }
2028 }
2029
2030 // ----------------------------------------------------------------------------
2031 // Initialization
2032
2033 void SystemDictionary::initialize(TRAPS) {
2034 // Allocate arrays
2035 _placeholders = new PlaceholderTable(_placeholder_table_size);
2036 _number_of_modifications = 0;
2037 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2038 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2039 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2040 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2041
2042 // Allocate private object used as system class loader lock
2043 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2044 // Initialize basic classes
2045 initialize_preloaded_classes(CHECK);
2046 }
2047
2048 // Compact table of directions on the initialization of klasses:
2049 static const short wk_init_info[] = {
2050 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2051 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2052 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2053 | (int)SystemDictionary::option ),
2054 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2055 #undef WK_KLASS_INIT_INFO
2056 0
2057 };
2058
2059 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2060 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2061 int info = wk_init_info[id - FIRST_WKID];
2062 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2063 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2064 InstanceKlass** klassp = &_well_known_klasses[id];
2065
2066 bool must_load;
2067 #if INCLUDE_JVMCI
2068 if (EnableJVMCI) {
2069 // If JVMCI is enabled we require its classes to be found.
2070 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2071 } else
2072 #endif
2073 {
2074 must_load = (init_opt < SystemDictionary::Opt);
2075 }
2076
2077 if ((*klassp) == NULL) {
2078 Klass* k;
2079 if (must_load) {
2080 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2081 } else {
2082 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2083 }
2084 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2085 }
2086 return ((*klassp) != NULL);
2087 }
2088
2089 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2090 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2091 for (int id = (int)start_id; id < (int)limit_id; id++) {
2092 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2093 int info = wk_init_info[id - FIRST_WKID];
2094 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2095 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2096
2097 initialize_wk_klass((WKID)id, opt, CHECK);
2098 }
2099
2100 // move the starting value forward to the limit:
2101 start_id = limit_id;
2102 }
2103
2104 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2105 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2106
2107 // Create the ModuleEntry for java.base. This call needs to be done here,
2108 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2109 ClassLoader::classLoader_init2(CHECK);
2110
2111 // Preload commonly used klasses
2112 WKID scan = FIRST_WKID;
2113 // first do Object, then String, Class
2114 #if INCLUDE_CDS
2115 if (UseSharedSpaces) {
2116 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2117 // Initialize the constant pool for the Object_class
2118 Object_klass()->constants()->restore_unshareable_info(CHECK);
2119 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2120 } else
2121 #endif
2122 {
2123 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2124 }
2125
2126 // Calculate offsets for String and Class classes since they are loaded and
2127 // can be used after this point.
2128 java_lang_String::compute_offsets();
2129 java_lang_Class::compute_offsets();
2130
2131 // Fixup mirrors for classes loaded before java.lang.Class.
2132 // These calls iterate over the objects currently in the perm gen
2133 // so calling them at this point is matters (not before when there
2134 // are fewer objects and not later after there are more objects
2135 // in the perm gen.
2136 Universe::initialize_basic_type_mirrors(CHECK);
2137 Universe::fixup_mirrors(CHECK);
2138
2139 // do a bunch more:
2140 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2141
2142 // Preload ref klasses and set reference types
2143 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2144 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2145
2146 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2147 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2148 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2149 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2150 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2151
2152 // JSR 292 classes
2153 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2154 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2155 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2156 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2157 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2158
2159 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2160 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2161 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2162 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2163 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2164 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2165 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2166 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2167 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2168 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2169
2170 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2171 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2172 _has_loadClassInternal = (method != NULL);
2173 }
2174 { // Compute whether we should use checkPackageAccess or NOT
2175 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2176 _has_checkPackageAccess = (method != NULL);
2177 }
2178 }
2179
2180 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2181 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2182 BasicType SystemDictionary::box_klass_type(Klass* k) {
2183 assert(k != NULL, "");
2184 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2185 if (_box_klasses[i] == k)
2186 return (BasicType)i;
2187 }
2188 return T_OBJECT;
2189 }
2190
2191 // Constraints on class loaders. The details of the algorithm can be
2192 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2193 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2194 // that the dictionary needs to maintain a set of contraints that
2195 // must be satisfied by all classes in the dictionary.
2196 // if defining is true, then LinkageError if already in dictionary
2197 // if initiating loader, then ok if InstanceKlass matches existing entry
2198
2199 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2200 InstanceKlass* k,
2201 Handle class_loader, bool defining,
2202 TRAPS) {
2203 const char *linkage_error1 = NULL;
2204 const char *linkage_error2 = NULL;
2205 {
2206 Symbol* name = k->name();
2207 ClassLoaderData *loader_data = class_loader_data(class_loader);
2208
2209 MutexLocker mu(SystemDictionary_lock, THREAD);
2210
2211 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data->dictionary());
2212 if (check != NULL) {
2213 // if different InstanceKlass - duplicate class definition,
2214 // else - ok, class loaded by a different thread in parallel,
2215 // we should only have found it if it was done loading and ok to use
2216 // dictionary only holds instance classes, placeholders
2217 // also holds array classes
2218
2219 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2220 if ((defining == true) || (k != check)) {
2221 linkage_error1 = "loader (instance of ";
2222 linkage_error2 = "): attempted duplicate class definition for name: \"";
2223 } else {
2224 return;
2225 }
2226 }
2227
2228 #ifdef ASSERT
2229 Symbol* ph_check = find_placeholder(name, loader_data);
2230 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2231 #endif
2232
2233 if (linkage_error1 == NULL) {
2234 if (constraints()->check_or_update(k, class_loader, name) == false) {
2235 linkage_error1 = "loader constraint violation: loader (instance of ";
2236 linkage_error2 = ") previously initiated loading for a different type with name \"";
2237 }
2238 }
2239 }
2240
2241 // Throw error now if needed (cannot throw while holding
2242 // SystemDictionary_lock because of rank ordering)
2243
2244 if (linkage_error1) {
2245 ResourceMark rm(THREAD);
2246 const char* class_loader_name = loader_name(class_loader());
2247 char* type_name = k->name()->as_C_string();
2248 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2249 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2250 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2251 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2252 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2253 }
2254 }
2255
2256
2257 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2258 // have been called.
2259 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2260 int p_index, unsigned int p_hash,
2261 InstanceKlass* k,
2262 Handle class_loader,
2263 TRAPS) {
2264 // Compile_lock prevents systemDictionary updates during compilations
2265 assert_locked_or_safepoint(Compile_lock);
2266 Symbol* name = k->name();
2267 ClassLoaderData *loader_data = class_loader_data(class_loader);
2268
2269 {
2270 MutexLocker mu1(SystemDictionary_lock, THREAD);
2271
2272 // See whether biased locking is enabled and if so set it for this
2273 // klass.
2274 // Note that this must be done past the last potential blocking
2275 // point / safepoint. We enable biased locking lazily using a
2276 // VM_Operation to iterate the SystemDictionary and installing the
2277 // biasable mark word into each InstanceKlass's prototype header.
2278 // To avoid race conditions where we accidentally miss enabling the
2279 // optimization for one class in the process of being added to the
2280 // dictionary, we must not safepoint after the test of
2281 // BiasedLocking::enabled().
2282 if (UseBiasedLocking && BiasedLocking::enabled()) {
2283 // Set biased locking bit for all loaded classes; it will be
2284 // cleared if revocation occurs too often for this type
2285 // NOTE that we must only do this when the class is initally
2286 // defined, not each time it is referenced from a new class loader
2287 if (k->class_loader() == class_loader()) {
2288 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2289 }
2290 }
2291
2292 // Make a new dictionary entry.
2293 Dictionary* dictionary = loader_data->dictionary();
2294 InstanceKlass* sd_check = find_class(d_index, d_hash, name, dictionary);
2295 if (sd_check == NULL) {
2296 dictionary->add_klass(d_index, d_hash, name, k);
2297 notice_modification();
2298 }
2299 #ifdef ASSERT
2300 sd_check = find_class(d_index, d_hash, name, dictionary);
2301 assert (sd_check != NULL, "should have entry in dictionary");
2302 // Note: there may be a placeholder entry: for circularity testing
2303 // or for parallel defines
2304 #endif
2305 SystemDictionary_lock->notify_all();
2306 }
2307 }
2308
2309
2310 // Try to find a class name using the loader constraints. The
2311 // loader constraints might know about a class that isn't fully loaded
2312 // yet and these will be ignored.
2313 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2314 Symbol* class_name, Handle class_loader, TRAPS) {
2315
2316 // First see if it has been loaded directly.
2317 // Force the protection domain to be null. (This removes protection checks.)
2318 Handle no_protection_domain;
2319 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2320 no_protection_domain, CHECK_NULL);
2321 if (klass != NULL)
2322 return klass;
2323
2324 // Now look to see if it has been loaded elsewhere, and is subject to
2325 // a loader constraint that would require this loader to return the
2326 // klass that is already loaded.
2327 if (FieldType::is_array(class_name)) {
2328 // For array classes, their Klass*s are not kept in the
2329 // constraint table. The element Klass*s are.
2330 FieldArrayInfo fd;
2331 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2332 if (t != T_OBJECT) {
2333 klass = Universe::typeArrayKlassObj(t);
2334 } else {
2335 MutexLocker mu(SystemDictionary_lock, THREAD);
2336 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2337 }
2338 // If element class already loaded, allocate array klass
2339 if (klass != NULL) {
2340 klass = klass->array_klass_or_null(fd.dimension());
2341 }
2342 } else {
2343 MutexLocker mu(SystemDictionary_lock, THREAD);
2344 // Non-array classes are easy: simply check the constraint table.
2345 klass = constraints()->find_constrained_klass(class_name, class_loader);
2346 }
2347
2348 return klass;
2349 }
2350
2351
2352 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2353 Handle class_loader1,
2354 Handle class_loader2,
2355 Thread* THREAD) {
2356 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2357 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2358
2359 Symbol* constraint_name = NULL;
2360 if (!FieldType::is_array(class_name)) {
2361 constraint_name = class_name;
2362 } else {
2363 // For array classes, their Klass*s are not kept in the
2364 // constraint table. The element classes are.
2365 FieldArrayInfo fd;
2366 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2367 // primitive types always pass
2368 if (t != T_OBJECT) {
2369 return true;
2370 } else {
2371 constraint_name = fd.object_key();
2372 }
2373 }
2374
2375 Dictionary* dictionary1 = loader_data1->dictionary();
2376 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2377 int d_index1 = dictionary1->hash_to_index(d_hash1);
2378
2379 Dictionary* dictionary2 = loader_data2->dictionary();
2380 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2381 int d_index2 = dictionary2->hash_to_index(d_hash2);
2382
2383 {
2384 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2385 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, dictionary1);
2386 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, dictionary2);
2387 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2388 klass2, class_loader2);
2389 }
2390 }
2391
2392 // Add entry to resolution error table to record the error when the first
2393 // attempt to resolve a reference to a class has failed.
2394 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2395 Symbol* error, Symbol* message) {
2396 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2397 int index = resolution_errors()->hash_to_index(hash);
2398 {
2399 MutexLocker ml(SystemDictionary_lock, Thread::current());
2400 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2401 }
2402 }
2403
2404 // Delete a resolution error for RedefineClasses for a constant pool is going away
2405 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2406 resolution_errors()->delete_entry(pool);
2407 }
2408
2409 // Lookup resolution error table. Returns error if found, otherwise NULL.
2410 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2411 Symbol** message) {
2412 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2413 int index = resolution_errors()->hash_to_index(hash);
2414 {
2415 MutexLocker ml(SystemDictionary_lock, Thread::current());
2416 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2417 if (entry != NULL) {
2418 *message = entry->message();
2419 return entry->error();
2420 } else {
2421 return NULL;
2422 }
2423 }
2424 }
2425
2426
2427 // Signature constraints ensure that callers and callees agree about
2428 // the meaning of type names in their signatures. This routine is the
2429 // intake for constraints. It collects them from several places:
2430 //
2431 // * LinkResolver::resolve_method (if check_access is true) requires
2432 // that the resolving class (the caller) and the defining class of
2433 // the resolved method (the callee) agree on each type in the
2434 // method's signature.
2435 //
2436 // * LinkResolver::resolve_interface_method performs exactly the same
2437 // checks.
2438 //
2439 // * LinkResolver::resolve_field requires that the constant pool
2440 // attempting to link to a field agree with the field's defining
2441 // class about the type of the field signature.
2442 //
2443 // * klassVtable::initialize_vtable requires that, when a class
2444 // overrides a vtable entry allocated by a superclass, that the
2445 // overriding method (i.e., the callee) agree with the superclass
2446 // on each type in the method's signature.
2447 //
2448 // * klassItable::initialize_itable requires that, when a class fills
2449 // in its itables, for each non-abstract method installed in an
2450 // itable, the method (i.e., the callee) agree with the interface
2451 // on each type in the method's signature.
2452 //
2453 // All those methods have a boolean (check_access, checkconstraints)
2454 // which turns off the checks. This is used from specialized contexts
2455 // such as bootstrapping, dumping, and debugging.
2456 //
2457 // No direct constraint is placed between the class and its
2458 // supertypes. Constraints are only placed along linked relations
2459 // between callers and callees. When a method overrides or implements
2460 // an abstract method in a supertype (superclass or interface), the
2461 // constraints are placed as if the supertype were the caller to the
2462 // overriding method. (This works well, since callers to the
2463 // supertype have already established agreement between themselves and
2464 // the supertype.) As a result of all this, a class can disagree with
2465 // its supertype about the meaning of a type name, as long as that
2466 // class neither calls a relevant method of the supertype, nor is
2467 // called (perhaps via an override) from the supertype.
2468 //
2469 //
2470 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2471 //
2472 // Make sure all class components (including arrays) in the given
2473 // signature will be resolved to the same class in both loaders.
2474 // Returns the name of the type that failed a loader constraint check, or
2475 // NULL if no constraint failed. No exception except OOME is thrown.
2476 // Arrays are not added to the loader constraint table, their elements are.
2477 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2478 Handle loader1, Handle loader2,
2479 bool is_method, TRAPS) {
2480 // Nothing to do if loaders are the same.
2481 if (loader1() == loader2()) {
2482 return NULL;
2483 }
2484
2485 SignatureStream sig_strm(signature, is_method);
2486 while (!sig_strm.is_done()) {
2487 if (sig_strm.is_object()) {
2488 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2489 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2490 return sig;
2491 }
2492 }
2493 sig_strm.next();
2494 }
2495 return NULL;
2496 }
2497
2498
2499 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2500 Symbol* signature,
2501 TRAPS) {
2502 methodHandle empty;
2503 assert(MethodHandles::is_signature_polymorphic(iid) &&
2504 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2505 iid != vmIntrinsics::_invokeGeneric,
2506 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2507
2508 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2509 int index = invoke_method_table()->hash_to_index(hash);
2510 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2511 methodHandle m;
2512 if (spe == NULL || spe->method() == NULL) {
2513 spe = NULL;
2514 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2515 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2516 if (!Arguments::is_interpreter_only()) {
2517 // Generate a compiled form of the MH intrinsic.
2518 AdapterHandlerLibrary::create_native_wrapper(m);
2519 // Check if have the compiled code.
2520 if (!m->has_compiled_code()) {
2521 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2522 "Out of space in CodeCache for method handle intrinsic", empty);
2523 }
2524 }
2525 // Now grab the lock. We might have to throw away the new method,
2526 // if a racing thread has managed to install one at the same time.
2527 {
2528 MutexLocker ml(SystemDictionary_lock, THREAD);
2529 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2530 if (spe == NULL)
2531 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2532 if (spe->method() == NULL)
2533 spe->set_method(m());
2534 }
2535 }
2536
2537 assert(spe != NULL && spe->method() != NULL, "");
2538 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2539 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2540 "MH intrinsic invariant");
2541 return spe->method();
2542 }
2543
2544 // Helper for unpacking the return value from linkMethod and linkCallSite.
2545 static methodHandle unpack_method_and_appendix(Handle mname,
2546 Klass* accessing_klass,
2547 objArrayHandle appendix_box,
2548 Handle* appendix_result,
2549 TRAPS) {
2550 methodHandle empty;
2551 if (mname.not_null()) {
2552 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2553 if (m != NULL) {
2554 oop appendix = appendix_box->obj_at(0);
2555 if (TraceMethodHandles) {
2556 #ifndef PRODUCT
2557 ttyLocker ttyl;
2558 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2559 m->print();
2560 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2561 tty->cr();
2562 #endif //PRODUCT
2563 }
2564 (*appendix_result) = Handle(THREAD, appendix);
2565 // the target is stored in the cpCache and if a reference to this
2566 // MethodName is dropped we need a way to make sure the
2567 // class_loader containing this method is kept alive.
2568 // FIXME: the appendix might also preserve this dependency.
2569 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2570 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2571 return methodHandle(THREAD, m);
2572 }
2573 }
2574 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2575 return empty;
2576 }
2577
2578 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2579 Symbol* name,
2580 Symbol* signature,
2581 Klass* accessing_klass,
2582 Handle *appendix_result,
2583 Handle *method_type_result,
2584 TRAPS) {
2585 methodHandle empty;
2586 assert(THREAD->can_call_java() ,"");
2587 Handle method_type =
2588 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2589
2590 int ref_kind = JVM_REF_invokeVirtual;
2591 oop name_oop = StringTable::intern(name, CHECK_(empty));
2592 Handle name_str (THREAD, name_oop);
2593 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2594 assert(appendix_box->obj_at(0) == NULL, "");
2595
2596 // This should not happen. JDK code should take care of that.
2597 if (accessing_klass == NULL || method_type.is_null()) {
2598 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2599 }
2600
2601 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2602 JavaCallArguments args;
2603 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2604 args.push_int(ref_kind);
2605 args.push_oop(Handle(THREAD, klass->java_mirror()));
2606 args.push_oop(name_str);
2607 args.push_oop(method_type);
2608 args.push_oop(appendix_box);
2609 JavaValue result(T_OBJECT);
2610 JavaCalls::call_static(&result,
2611 SystemDictionary::MethodHandleNatives_klass(),
2612 vmSymbols::linkMethod_name(),
2613 vmSymbols::linkMethod_signature(),
2614 &args, CHECK_(empty));
2615 Handle mname(THREAD, (oop) result.get_jobject());
2616 (*method_type_result) = method_type;
2617 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2618 }
2619
2620 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2621 // We must ensure that all class loaders everywhere will reach this class, for any client.
2622 // This is a safe bet for public classes in java.lang, such as Object and String.
2623 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2624 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2625 static bool is_always_visible_class(oop mirror) {
2626 Klass* klass = java_lang_Class::as_Klass(mirror);
2627 if (klass->is_objArray_klass()) {
2628 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2629 }
2630 if (klass->is_typeArray_klass()) {
2631 return true; // primitive array
2632 }
2633 assert(klass->is_instance_klass(), "%s", klass->external_name());
2634 return klass->is_public() &&
2635 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2636 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
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(!oopDesc::is_null(mirror), "%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 (ss.is_object() && 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 if (sel_klass->is_objArray_klass())
2698 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2699 if (sel_klass->is_instance_klass()) {
2700 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2701 }
2702 }
2703 }
2704 assert(arg == npts, "");
2705
2706 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2707 JavaCallArguments args(Handle(THREAD, rt()));
2708 args.push_oop(pts);
2709 JavaValue result(T_OBJECT);
2710 JavaCalls::call_static(&result,
2711 SystemDictionary::MethodHandleNatives_klass(),
2712 vmSymbols::findMethodHandleType_name(),
2713 vmSymbols::findMethodHandleType_signature(),
2714 &args, CHECK_(empty));
2715 Handle method_type(THREAD, (oop) result.get_jobject());
2716
2717 if (can_be_cached) {
2718 // We can cache this MethodType inside the JVM.
2719 MutexLocker ml(SystemDictionary_lock, THREAD);
2720 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2721 if (spe == NULL)
2722 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2723 if (spe->method_type() == NULL) {
2724 spe->set_method_type(method_type());
2725 }
2726 }
2727
2728 // report back to the caller with the MethodType
2729 return method_type;
2730 }
2731
2732 // Ask Java code to find or construct a method handle constant.
2733 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2734 int ref_kind, //e.g., JVM_REF_invokeVirtual
2735 Klass* callee,
2736 Symbol* name_sym,
2737 Symbol* signature,
2738 TRAPS) {
2739 Handle empty;
2740 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2741 Handle type;
2742 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2743 type = find_method_handle_type(signature, caller, CHECK_(empty));
2744 } else if (caller == NULL) {
2745 // This should not happen. JDK code should take care of that.
2746 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2747 } else {
2748 ResourceMark rm(THREAD);
2749 SignatureStream ss(signature, false);
2750 if (!ss.is_done()) {
2751 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2752 Handle(THREAD, caller->protection_domain()),
2753 SignatureStream::NCDFError, CHECK_(empty));
2754 type = Handle(THREAD, mirror);
2755 ss.next();
2756 if (!ss.is_done()) type = Handle(); // error!
2757 }
2758 }
2759 if (type.is_null()) {
2760 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2761 }
2762
2763 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2764 JavaCallArguments args;
2765 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2766 args.push_int(ref_kind);
2767 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2768 args.push_oop(name);
2769 args.push_oop(type);
2770 JavaValue result(T_OBJECT);
2771 JavaCalls::call_static(&result,
2772 SystemDictionary::MethodHandleNatives_klass(),
2773 vmSymbols::linkMethodHandleConstant_name(),
2774 vmSymbols::linkMethodHandleConstant_signature(),
2775 &args, CHECK_(empty));
2776 return Handle(THREAD, (oop) result.get_jobject());
2777 }
2778
2779 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2780 // name and signature, as interpreted relative to the given class loader.
2781 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2782 Handle bootstrap_specifier,
2783 Symbol* name,
2784 Symbol* type,
2785 Handle *appendix_result,
2786 Handle *method_type_result,
2787 TRAPS) {
2788 methodHandle empty;
2789 Handle bsm, info;
2790 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2791 bsm = bootstrap_specifier;
2792 } else {
2793 assert(bootstrap_specifier->is_objArray(), "");
2794 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2795 int len = args->length();
2796 assert(len >= 1, "");
2797 bsm = Handle(THREAD, args->obj_at(0));
2798 if (len > 1) {
2799 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2800 for (int i = 1; i < len; i++)
2801 args1->obj_at_put(i-1, args->obj_at(i));
2802 info = Handle(THREAD, args1);
2803 }
2804 }
2805 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2806 "caller must supply a valid BSM");
2807
2808 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2809 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2810
2811 // This should not happen. JDK code should take care of that.
2812 if (caller == NULL || method_type.is_null()) {
2813 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2814 }
2815
2816 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2817 assert(appendix_box->obj_at(0) == NULL, "");
2818
2819 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2820 JavaCallArguments args;
2821 args.push_oop(Handle(THREAD, caller->java_mirror()));
2822 args.push_oop(bsm);
2823 args.push_oop(method_name);
2824 args.push_oop(method_type);
2825 args.push_oop(info);
2826 args.push_oop(appendix_box);
2827 JavaValue result(T_OBJECT);
2828 JavaCalls::call_static(&result,
2829 SystemDictionary::MethodHandleNatives_klass(),
2830 vmSymbols::linkCallSite_name(),
2831 vmSymbols::linkCallSite_signature(),
2832 &args, CHECK_(empty));
2833 Handle mname(THREAD, (oop) result.get_jobject());
2834 (*method_type_result) = method_type;
2835 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2836 }
2837
2838 // Protection domain cache table handling
2839
2840 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2841 return _pd_cache_table->get(protection_domain);
2842 }
2843
2844 void SystemDictionary::reorder_dictionary_for_sharing() {
2845 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2846 }
2847
2848 size_t SystemDictionary::count_bytes_for_buckets() {
2849 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2850 }
2851
2852 size_t SystemDictionary::count_bytes_for_table() {
2853 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2854 }
2855
2856 void SystemDictionary::copy_buckets(char* top, char* end) {
2857 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2858 }
2859
2860 void SystemDictionary::copy_table(char* top, char* end) {
2861 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2862 }
2863
2864 // ----------------------------------------------------------------------------
2865 void SystemDictionary::print_shared(outputStream *st) {
2866 shared_dictionary()->print_on(st);
2867 }
2868
2869 void SystemDictionary::print_on(outputStream *st) {
2870 if (shared_dictionary() != NULL) {
2871 st->print_cr("Shared Dictionary");
2872 shared_dictionary()->print_on(st);
2873 st->cr();
2874 }
2875
2876 GCMutexLocker mu(SystemDictionary_lock);
2877
2878 ClassLoaderDataGraph::print_dictionary(st);
2879
2880 // Placeholders
2881 placeholders()->print_on(st);
2882 st->cr();
2883
2884 // loader constraints - print under SD_lock
2885 constraints()->print_on(st);
2886 st->cr();
2887
2888 _pd_cache_table->print_on(st);
2889 st->cr();
2890 }
2891
2892 void SystemDictionary::verify() {
2893 guarantee(constraints() != NULL,
2894 "Verify of loader constraints failed");
2895 guarantee(placeholders()->number_of_entries() >= 0,
2896 "Verify of placeholders failed");
2897
2898 GCMutexLocker mu(SystemDictionary_lock);
2899
2900 // Verify dictionary
2901 ClassLoaderDataGraph::verify_dictionary();
2902
2903 placeholders()->verify();
2904
2905 // Verify constraint table
2906 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2907 constraints()->verify(placeholders());
2908
2909 _pd_cache_table->verify();
2910 }
2911
2912 void SystemDictionary::dump(outputStream *st, bool verbose) {
2913 assert_locked_or_safepoint(SystemDictionary_lock);
2914 if (verbose) {
2915 print_on(st);
2916 } else {
2917 if (shared_dictionary() != NULL) {
2918 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
2919 }
2920 ClassLoaderDataGraph::print_dictionary_statistics(st);
2921 placeholders()->print_table_statistics(st, "Placeholder Table");
2922 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2923 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2924 }
2925 }
2926
2927 // Utility for dumping dictionaries.
2928 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2929 DCmdWithParser(output, heap),
2930 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2931 "BOOLEAN", false, "false") {
2932 _dcmdparser.add_dcmd_option(&_verbose);
2933 }
2934
2935 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2936 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2937 _verbose.value());
2938 VMThread::execute(&dumper);
2939 }
2940
2941 int SystemDictionaryDCmd::num_arguments() {
2942 ResourceMark rm;
2943 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2944 if (dcmd != NULL) {
2945 DCmdMark mark(dcmd);
2946 return dcmd->_dcmdparser.num_arguments();
2947 } else {
2948 return 0;
2949 }
2950 }
2951
2952 class CombineDictionariesClosure : public CLDClosure {
2953 private:
2954 Dictionary* _master_dictionary;
2955 public:
2956 CombineDictionariesClosure(Dictionary* master_dictionary) :
2957 _master_dictionary(master_dictionary) {}
2958 void do_cld(ClassLoaderData* cld) {
2959 ResourceMark rm;
2960 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2961 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
2962 Dictionary* curr_dictionary = cld->dictionary();
2963 DictionaryEntry* p = curr_dictionary->bucket(i);
2964 while (p != NULL) {
2965 Symbol* name = p->instance_klass()->name();
2966 unsigned int d_hash = _master_dictionary->compute_hash(name);
2967 int d_index = _master_dictionary->hash_to_index(d_hash);
2968 DictionaryEntry* next = p->next();
2969 if (p->literal()->class_loader_data() != cld) {
2970 // This is an initiating class loader entry; don't use it
2971 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
2972 curr_dictionary->free_entry(p);
2973 } else {
2974 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
2975 curr_dictionary->unlink_entry(p);
2976 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
2977 _master_dictionary->add_entry(d_index, p);
2978 }
2979 p = next;
2980 }
2981 *curr_dictionary->bucket_addr(i) = NULL;
2982 }
2983 }
2984 }
2985 };
2986
2987 // Combining platform and system loader dictionaries into boot loader dictionaries.
2988 // During run time, we only have one shared dictionary.
2989 void SystemDictionary::combine_shared_dictionaries() {
2990 assert(DumpSharedSpaces, "dump time only");
2991 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
2992 CombineDictionariesClosure cdc(master_dictionary);
2993 ClassLoaderDataGraph::cld_do(&cdc);
2994
2995 // These tables are no longer valid or necessary. Keeping them around will
2996 // cause SystemDictionary::verify() to fail. Let's empty them.
2997 _placeholders = new PlaceholderTable(_placeholder_table_size);
2998 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2999
3000 NOT_PRODUCT(SystemDictionary::verify());
3001 }
3002
3003 // caller needs ResourceMark
3004 const char* SystemDictionary::loader_name(const oop loader) {
3005 return ((loader) == NULL ? "<bootloader>" :
3006 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3007 }
3008
3009 // caller needs ResourceMark
3010 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3011 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3012 SystemDictionary::loader_name(loader_data->class_loader()));
3013 }