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 "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderExt.hpp"
33 #include "classfile/dictionary.hpp"
34 #include "classfile/javaClasses.inline.hpp"
35 #include "classfile/klassFactory.hpp"
36 #include "classfile/loaderConstraints.hpp"
37 #include "classfile/packageEntry.hpp"
38 #include "classfile/placeholders.hpp"
39 #include "classfile/protectionDomainCache.hpp"
40 #include "classfile/resolutionErrors.hpp"
41 #include "classfile/stringTable.hpp"
42 #include "classfile/systemDictionary.hpp"
43 #include "classfile/vmSymbols.hpp"
44 #include "code/codeCache.hpp"
45 #include "compiler/compileBroker.hpp"
46 #include "gc/shared/gcLocker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "interpreter/bytecodeStream.hpp"
49 #include "interpreter/interpreter.hpp"
50 #include "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/instanceKlass.hpp"
57 #include "oops/instanceRefKlass.hpp"
58 #include "oops/klass.inline.hpp"
59 #include "oops/methodData.hpp"
60 #include "oops/objArrayKlass.hpp"
61 #include "oops/objArrayOop.inline.hpp"
62 #include "oops/oop.inline.hpp"
63 #include "oops/symbol.hpp"
64 #include "oops/typeArrayKlass.hpp"
65 #include "oops/valueKlass.hpp"
66 #include "prims/jvmtiEnvBase.hpp"
67 #include "prims/resolvedMethodTable.hpp"
68 #include "prims/methodHandles.hpp"
69 #include "runtime/arguments.hpp"
70 #include "runtime/arguments_ext.hpp"
71 #include "runtime/biasedLocking.hpp"
72 #include "runtime/fieldType.hpp"
73 #include "runtime/handles.inline.hpp"
74 #include "runtime/java.hpp"
75 #include "runtime/javaCalls.hpp"
76 #include "runtime/mutexLocker.hpp"
77 #include "runtime/orderAccess.inline.hpp"
78 #include "runtime/os.hpp"
79 #include "runtime/signature.hpp"
80 #include "services/classLoadingService.hpp"
81 #include "services/diagnosticCommand.hpp"
82 #include "services/threadService.hpp"
83 #include "trace/tracing.hpp"
84 #include "utilities/macros.hpp"
85 #if INCLUDE_CDS
86 #include "classfile/sharedClassUtil.hpp"
87 #include "classfile/systemDictionaryShared.hpp"
88 #endif
89 #if INCLUDE_JVMCI
90 #include "jvmci/jvmciRuntime.hpp"
91 #endif
92
93 PlaceholderTable* SystemDictionary::_placeholders = NULL;
94 Dictionary* SystemDictionary::_shared_dictionary = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 int SystemDictionary::_number_of_modifications = 0;
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 bool SystemDictionary::_has_loadClassInternal = false;
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // lazily initialized klass variables
115 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
116
117 // Default ProtectionDomainCacheSize value
118
119 const int defaultProtectionDomainCacheSize = 1009;
120
121
122 // ----------------------------------------------------------------------------
123 // Java-level SystemLoader and PlatformLoader
124
125 oop SystemDictionary::java_system_loader() {
126 return _java_system_loader;
127 }
128
129 oop SystemDictionary::java_platform_loader() {
130 return _java_platform_loader;
131 }
132
133 void SystemDictionary::compute_java_loaders(TRAPS) {
134 JavaValue result(T_OBJECT);
135 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
136 JavaCalls::call_static(&result,
137 class_loader_klass,
138 vmSymbols::getSystemClassLoader_name(),
139 vmSymbols::void_classloader_signature(),
140 CHECK);
141
142 _java_system_loader = (oop)result.get_jobject();
143
144 JavaCalls::call_static(&result,
145 class_loader_klass,
146 vmSymbols::getPlatformClassLoader_name(),
147 vmSymbols::void_classloader_signature(),
148 CHECK);
149
150 _java_platform_loader = (oop)result.get_jobject();
151
152 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
153 }
154
155 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
156 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
157 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
158 }
159
160 // ----------------------------------------------------------------------------
161 // Parallel class loading check
162
163 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
164 if (UnsyncloadClass || class_loader.is_null()) return true;
165 if (AlwaysLockClassLoader) return false;
166 return java_lang_ClassLoader::parallelCapable(class_loader());
167 }
168 // ----------------------------------------------------------------------------
169 // ParallelDefineClass flag does not apply to bootclass loader
170 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
171 if (class_loader.is_null()) return false;
172 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
173 return true;
174 }
175 return false;
176 }
177
178 // Returns true if the passed class loader is the builtin application class loader
179 // or a custom system class loader. A customer system class loader can be
180 // specified via -Djava.system.class.loader.
181 bool SystemDictionary::is_system_class_loader(oop class_loader) {
182 if (class_loader == NULL) {
183 return false;
184 }
185 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
186 class_loader == _java_system_loader);
187 }
188
189 // Returns true if the passed class loader is the platform class loader.
190 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
191 if (class_loader == NULL) {
192 return false;
193 }
194 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
195 }
196
197 // ----------------------------------------------------------------------------
198 // Resolving of classes
199
200 // Forwards to resolve_or_null
201
202 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
203 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
204 if (HAS_PENDING_EXCEPTION || klass == NULL) {
205 // can return a null klass
206 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
207 }
208 return klass;
209 }
210
211 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
212 bool throw_error,
213 Klass* klass, TRAPS) {
214 if (HAS_PENDING_EXCEPTION) {
215 // If we have a pending exception we forward it to the caller, unless throw_error is true,
216 // in which case we have to check whether the pending exception is a ClassNotFoundException,
217 // and if so convert it to a NoClassDefFoundError
218 // And chain the original ClassNotFoundException
219 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
220 ResourceMark rm(THREAD);
221 assert(klass == NULL, "Should not have result with exception pending");
222 Handle e(THREAD, PENDING_EXCEPTION);
223 CLEAR_PENDING_EXCEPTION;
224 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
225 } else {
226 return NULL;
227 }
228 }
229 // Class not found, throw appropriate error or exception depending on value of throw_error
230 if (klass == NULL) {
231 ResourceMark rm(THREAD);
232 if (throw_error) {
233 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
234 } else {
235 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
236 }
237 }
238 return klass;
239 }
240
241
242 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
243 bool throw_error, TRAPS)
244 {
245 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
246 }
247
248
249 // Forwards to resolve_instance_class_or_null
250
251 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
252 assert(THREAD->can_call_java(),
253 "can not load classes with compiler thread: class=%s, classloader=%s",
254 class_name->as_C_string(),
255 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
256 if (FieldType::is_array(class_name)) {
257 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
258 } else if (FieldType::is_obj(class_name)) {
259 ResourceMark rm(THREAD);
260 // Ignore wrapping L and ;. (and Q and ; for value types);
261 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
262 class_name->utf8_length() - 2, CHECK_NULL);
263 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
264 } else {
265 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
266 }
267 }
268
269 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
270 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
271 }
272
273 // Forwards to resolve_instance_class_or_null
274
275 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
276 Handle class_loader,
277 Handle protection_domain,
278 TRAPS) {
279 assert(FieldType::is_array(class_name), "must be array");
280 Klass* k = NULL;
281 FieldArrayInfo fd;
282 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
283 // of this call
284 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
285 if (t == T_OBJECT || t == T_VALUETYPE) {
286 // naked oop "k" is OK here -- we assign back into it
287 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
288 class_loader,
289 protection_domain,
290 CHECK_NULL);
291 if (k != NULL) {
292 k = k->array_klass(fd.dimension(), CHECK_NULL);
293 }
294 } else {
295 k = Universe::typeArrayKlassObj(t);
296 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
297 }
298 return k;
299 }
300
301 // Must be called for any super-class or super-interface resolution
302 // during class definition to allow class circularity checking
303 // super-interface callers:
304 // parse_interfaces - for defineClass & jvmtiRedefineClasses
305 // super-class callers:
306 // ClassFileParser - for defineClass & jvmtiRedefineClasses
307 // load_shared_class - while loading a class from shared archive
308 // resolve_instance_class_or_null:
309 // via: handle_parallel_super_load
310 // when resolving a class that has an existing placeholder with
311 // a saved superclass [i.e. a defineClass is currently in progress]
312 // if another thread is trying to resolve the class, it must do
313 // super-class checks on its own thread to catch class circularity
314 // This last call is critical in class circularity checking for cases
315 // where classloading is delegated to different threads and the
316 // classloader lock is released.
317 // Take the case: Base->Super->Base
318 // 1. If thread T1 tries to do a defineClass of class Base
319 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
320 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
321 // so it tries to load Super
322 // 3. If we load the class internally, or user classloader uses same thread
323 // loadClassFromxxx or defineClass via parseClassFile Super ...
324 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
325 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
326 // 3.4 calls resolve_super_or_fail Base
327 // 3.5 finds T1,Base -> throws class circularity
328 //OR 4. If T2 tries to resolve Super via defineClass Super ...
329 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
330 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
331 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
332 // 4.4 finds T2, Super -> throws class circularity
333 // Must be called, even if superclass is null, since this is
334 // where the placeholder entry is created which claims this
335 // thread is loading this class/classloader.
336 // Be careful when modifying this code: once you have run
337 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
338 // you need to find_and_remove it before returning.
339 // So be careful to not exit with a CHECK_ macro betweeen these calls.
340 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
341 Symbol* class_name,
342 Handle class_loader,
343 Handle protection_domain,
344 bool is_superclass,
345 TRAPS) {
346 #if INCLUDE_CDS
347 if (DumpSharedSpaces) {
348 // Special processing for CDS dump time.
349 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
350 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
351 if (k) {
352 return k;
353 }
354 }
355 #endif // INCLUDE_CDS
356
357 // Double-check, if child class is already loaded, just return super-class,interface
358 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
359 // dictionary.
360 // Make sure there's a placeholder for the *child* before resolving.
361 // Used as a claim that this thread is currently loading superclass/classloader
362 // Used here for ClassCircularity checks and also for heap verification
363 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
364 // Must check ClassCircularity before checking if super class is already loaded.
365 //
366 // We might not already have a placeholder if this child_name was
367 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
368 // the name of the class might not be known until the stream is actually
369 // parsed.
370 // Bugs 4643874, 4715493
371
372 ClassLoaderData* loader_data = class_loader_data(class_loader);
373 Dictionary* dictionary = loader_data->dictionary();
374 unsigned int d_hash = dictionary->compute_hash(child_name);
375 unsigned int p_hash = placeholders()->compute_hash(child_name);
376 int p_index = placeholders()->hash_to_index(p_hash);
377 // can't throw error holding a lock
378 bool child_already_loaded = false;
379 bool throw_circularity_error = false;
380 {
381 MutexLocker mu(SystemDictionary_lock, THREAD);
382 Klass* childk = find_class(d_hash, child_name, dictionary);
383 Klass* quicksuperk;
384 // to support // loading: if child done loading, just return superclass
385 // if class_name, & class_loader don't match:
386 // if initial define, SD update will give LinkageError
387 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
388 // so we don't throw an exception here.
389 // see: nsk redefclass014 & java.lang.instrument Instrument032
390 if ((childk != NULL ) && (is_superclass) &&
391 ((quicksuperk = childk->super()) != NULL) &&
392
393 ((quicksuperk->name() == class_name) &&
394 (quicksuperk->class_loader() == class_loader()))) {
395 return quicksuperk;
396 } else {
397 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
398 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
399 throw_circularity_error = true;
400 }
401 }
402 if (!throw_circularity_error) {
403 // Be careful not to exit resolve_super
404 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
405 }
406 }
407 if (throw_circularity_error) {
408 ResourceMark rm(THREAD);
409 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
410 }
411
412 // java.lang.Object should have been found above
413 assert(class_name != NULL, "null super class for resolving");
414 // Resolve the super class or interface, check results on return
415 Klass* superk = SystemDictionary::resolve_or_null(class_name,
416 class_loader,
417 protection_domain,
418 THREAD);
419
420 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
421 // It is no longer necessary to keep the placeholder table alive until update_dictionary
422 // or error. GC used to walk the placeholder table as strong roots.
423 // The instanceKlass is kept alive because the class loader is on the stack,
424 // which keeps the loader_data alive, as well as all instanceKlasses in
425 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
426 {
427 MutexLocker mu(SystemDictionary_lock, THREAD);
428 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
429 SystemDictionary_lock->notify_all();
430 }
431 if (HAS_PENDING_EXCEPTION || superk == NULL) {
432 // can null superk
433 superk = handle_resolution_exception(class_name, true, superk, THREAD);
434 }
435
436 return superk;
437 }
438
439 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
440 Handle class_loader,
441 Handle protection_domain,
442 TRAPS) {
443 if(!has_checkPackageAccess()) return;
444
445 // Now we have to call back to java to check if the initating class has access
446 JavaValue result(T_VOID);
447 LogTarget(Debug, protectiondomain) lt;
448 if (lt.is_enabled()) {
449 ResourceMark rm;
450 // Print out trace information
451 LogStream ls(lt);
452 ls.print_cr("Checking package access");
453 ls.print("class loader: "); class_loader()->print_value_on(&ls);
454 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
455 ls.print(" loading: "); klass->print_value_on(&ls);
456 ls.cr();
457 }
458
459 // This handle and the class_loader handle passed in keeps this class from
460 // being unloaded through several GC points.
461 // The class_loader handle passed in is the initiating loader.
462 Handle mirror(THREAD, klass->java_mirror());
463
464 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
465 JavaCalls::call_special(&result,
466 class_loader,
467 system_loader,
468 vmSymbols::checkPackageAccess_name(),
469 vmSymbols::class_protectiondomain_signature(),
470 mirror,
471 protection_domain,
472 THREAD);
473
474 if (HAS_PENDING_EXCEPTION) {
475 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
476 } else {
477 log_debug(protectiondomain)("granted");
478 }
479
480 if (HAS_PENDING_EXCEPTION) return;
481
482 // If no exception has been thrown, we have validated the protection domain
483 // Insert the protection domain of the initiating class into the set.
484 {
485 ClassLoaderData* loader_data = class_loader_data(class_loader);
486 Dictionary* dictionary = loader_data->dictionary();
487
488 Symbol* kn = klass->name();
489 unsigned int d_hash = dictionary->compute_hash(kn);
490
491 MutexLocker mu(SystemDictionary_lock, THREAD);
492 int d_index = dictionary->hash_to_index(d_hash);
493 dictionary->add_protection_domain(d_index, d_hash, klass,
494 protection_domain, THREAD);
495 }
496 }
497
498 // We only get here if this thread finds that another thread
499 // has already claimed the placeholder token for the current operation,
500 // but that other thread either never owned or gave up the
501 // object lock
502 // Waits on SystemDictionary_lock to indicate placeholder table updated
503 // On return, caller must recheck placeholder table state
504 //
505 // We only get here if
506 // 1) custom classLoader, i.e. not bootstrap classloader
507 // 2) UnsyncloadClass not set
508 // 3) custom classLoader has broken the class loader objectLock
509 // so another thread got here in parallel
510 //
511 // lockObject must be held.
512 // Complicated dance due to lock ordering:
513 // Must first release the classloader object lock to
514 // allow initial definer to complete the class definition
515 // and to avoid deadlock
516 // Reclaim classloader lock object with same original recursion count
517 // Must release SystemDictionary_lock after notify, since
518 // class loader lock must be claimed before SystemDictionary_lock
519 // to prevent deadlocks
520 //
521 // The notify allows applications that did an untimed wait() on
522 // the classloader object lock to not hang.
523 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
524 assert_lock_strong(SystemDictionary_lock);
525
526 bool calledholdinglock
527 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
528 assert(calledholdinglock,"must hold lock for notify");
529 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
530 ObjectSynchronizer::notifyall(lockObject, THREAD);
531 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
532 SystemDictionary_lock->wait();
533 SystemDictionary_lock->unlock();
534 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
535 SystemDictionary_lock->lock();
536 }
537
538 // If the class in is in the placeholder table, class loading is in progress
539 // For cases where the application changes threads to load classes, it
540 // is critical to ClassCircularity detection that we try loading
541 // the superclass on the same thread internally, so we do parallel
542 // super class loading here.
543 // This also is critical in cases where the original thread gets stalled
544 // even in non-circularity situations.
545 // Note: must call resolve_super_or_fail even if null super -
546 // to force placeholder entry creation for this class for circularity detection
547 // Caller must check for pending exception
548 // Returns non-null Klass* if other thread has completed load
549 // and we are done,
550 // If return null Klass* and no pending exception, the caller must load the class
551 InstanceKlass* SystemDictionary::handle_parallel_super_load(
552 Symbol* name, Symbol* superclassname, Handle class_loader,
553 Handle protection_domain, Handle lockObject, TRAPS) {
554
555 ClassLoaderData* loader_data = class_loader_data(class_loader);
556 Dictionary* dictionary = loader_data->dictionary();
557 unsigned int d_hash = dictionary->compute_hash(name);
558 unsigned int p_hash = placeholders()->compute_hash(name);
559 int p_index = placeholders()->hash_to_index(p_hash);
560
561 // superk is not used, resolve_super called for circularity check only
562 // This code is reached in two situations. One if this thread
563 // is loading the same class twice (e.g. ClassCircularity, or
564 // java.lang.instrument).
565 // The second is if another thread started the resolve_super first
566 // and has not yet finished.
567 // In both cases the original caller will clean up the placeholder
568 // entry on error.
569 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
570 superclassname,
571 class_loader,
572 protection_domain,
573 true,
574 CHECK_NULL);
575
576 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
577 // Serial class loaders and bootstrap classloader do wait for superclass loads
578 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
579 MutexLocker mu(SystemDictionary_lock, THREAD);
580 // Check if classloading completed while we were loading superclass or waiting
581 return find_class(d_hash, name, dictionary);
582 }
583
584 // must loop to both handle other placeholder updates
585 // and spurious notifications
586 bool super_load_in_progress = true;
587 PlaceholderEntry* placeholder;
588 while (super_load_in_progress) {
589 MutexLocker mu(SystemDictionary_lock, THREAD);
590 // Check if classloading completed while we were loading superclass or waiting
591 InstanceKlass* check = find_class(d_hash, name, dictionary);
592 if (check != NULL) {
593 // Klass is already loaded, so just return it
594 return check;
595 } else {
596 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
597 if (placeholder && placeholder->super_load_in_progress() ){
598 // Before UnsyncloadClass:
599 // We only get here if the application has released the
600 // classloader lock when another thread was in the middle of loading a
601 // superclass/superinterface for this class, and now
602 // this thread is also trying to load this class.
603 // To minimize surprises, the first thread that started to
604 // load a class should be the one to complete the loading
605 // with the classfile it initially expected.
606 // This logic has the current thread wait once it has done
607 // all the superclass/superinterface loading it can, until
608 // the original thread completes the class loading or fails
609 // If it completes we will use the resulting InstanceKlass
610 // which we will find below in the systemDictionary.
611 // We also get here for parallel bootstrap classloader
612 if (class_loader.is_null()) {
613 SystemDictionary_lock->wait();
614 } else {
615 double_lock_wait(lockObject, THREAD);
616 }
617 } else {
618 // If not in SD and not in PH, other thread's load must have failed
619 super_load_in_progress = false;
620 }
621 }
622 }
623 return NULL;
624 }
625
626 static void post_class_load_event(EventClassLoad* event,
627 const InstanceKlass* k,
628 const ClassLoaderData* init_cld) {
629 #if INCLUDE_TRACE
630 assert(event != NULL, "invariant");
631 assert(k != NULL, "invariant");
632 if (event->should_commit()) {
633 event->set_loadedClass(k);
634 event->set_definingClassLoader(k->class_loader_data());
635 event->set_initiatingClassLoader(init_cld);
636 event->commit();
637 }
638 #endif // INCLUDE_TRACE
639 }
640
641 static void class_define_event(InstanceKlass* k,
642 const ClassLoaderData* def_cld) {
643 #if INCLUDE_TRACE
644 EventClassDefine event;
645 if (event.should_commit()) {
646 event.set_definedClass(k);
647 event.set_definingClassLoader(def_cld);
648 event.commit();
649 }
650 #endif // INCLUDE_TRACE
651 }
652
653 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
654 Handle class_loader,
655 Handle protection_domain,
656 TRAPS) {
657 Klass* k = do_resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
658 return k;
659 }
660
661 // Be careful when modifying this code: once you have run
662 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
663 // you need to find_and_remove it before returning.
664 // So be careful to not exit with a CHECK_ macro betweeen these calls.
665 Klass* SystemDictionary::do_resolve_instance_class_or_null(Symbol* name,
666 Handle class_loader,
667 Handle protection_domain,
668 TRAPS) {
669 assert(name != NULL && !FieldType::is_array(name) &&
670 !FieldType::is_obj(name), "invalid class name");
671
672 EventClassLoad class_load_start_event;
673
674 HandleMark hm(THREAD);
675
676 // Fix for 4474172; see evaluation for more details
677 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
678 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
679 Dictionary* dictionary = loader_data->dictionary();
680 unsigned int d_hash = dictionary->compute_hash(name);
681
682 // Do lookup to see if class already exist and the protection domain
683 // has the right access
684 // This call uses find which checks protection domain already matches
685 // All subsequent calls use find_class, and set has_loaded_class so that
686 // before we return a result we call out to java to check for valid protection domain
687 // to allow returning the Klass* and add it to the pd_set if it is valid
688 {
689 Klass* probe = dictionary->find(d_hash, name, protection_domain);
690 if (probe != NULL) return probe;
691 }
692
693 // Non-bootstrap class loaders will call out to class loader and
694 // define via jvm/jni_DefineClass which will acquire the
695 // class loader object lock to protect against multiple threads
696 // defining the class in parallel by accident.
697 // This lock must be acquired here so the waiter will find
698 // any successful result in the SystemDictionary and not attempt
699 // the define
700 // ParallelCapable Classloaders and the bootstrap classloader,
701 // or all classloaders with UnsyncloadClass do not acquire lock here
702 bool DoObjectLock = true;
703 if (is_parallelCapable(class_loader)) {
704 DoObjectLock = false;
705 }
706
707 unsigned int p_hash = placeholders()->compute_hash(name);
708 int p_index = placeholders()->hash_to_index(p_hash);
709
710 // Class is not in SystemDictionary so we have to do loading.
711 // Make sure we are synchronized on the class loader before we proceed
712 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
713 check_loader_lock_contention(lockObject, THREAD);
714 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
715
716 // Check again (after locking) if class already exist in SystemDictionary
717 bool class_has_been_loaded = false;
718 bool super_load_in_progress = false;
719 bool havesupername = false;
720 InstanceKlass* k = NULL;
721 PlaceholderEntry* placeholder;
722 Symbol* superclassname = NULL;
723
724 {
725 MutexLocker mu(SystemDictionary_lock, THREAD);
726 InstanceKlass* check = find_class(d_hash, name, dictionary);
727 if (check != NULL) {
728 // Klass is already loaded, so just return it
729 class_has_been_loaded = true;
730 k = check;
731 } else {
732 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
733 if (placeholder && placeholder->super_load_in_progress()) {
734 super_load_in_progress = true;
735 if (placeholder->havesupername() == true) {
736 superclassname = placeholder->supername();
737 havesupername = true;
738 }
739 }
740 }
741 }
742
743 // If the class is in the placeholder table, class loading is in progress
744 if (super_load_in_progress && havesupername==true) {
745 k = handle_parallel_super_load(name,
746 superclassname,
747 class_loader,
748 protection_domain,
749 lockObject, THREAD);
750 if (HAS_PENDING_EXCEPTION) {
751 return NULL;
752 }
753 if (k != NULL) {
754 class_has_been_loaded = true;
755 }
756 }
757
758 bool throw_circularity_error = false;
759 if (!class_has_been_loaded) {
760 bool load_instance_added = false;
761
762 // add placeholder entry to record loading instance class
763 // Five cases:
764 // All cases need to prevent modifying bootclasssearchpath
765 // in parallel with a classload of same classname
766 // Redefineclasses uses existence of the placeholder for the duration
767 // of the class load to prevent concurrent redefinition of not completely
768 // defined classes.
769 // case 1. traditional classloaders that rely on the classloader object lock
770 // - no other need for LOAD_INSTANCE
771 // case 2. traditional classloaders that break the classloader object lock
772 // as a deadlock workaround. Detection of this case requires that
773 // this check is done while holding the classloader object lock,
774 // and that lock is still held when calling classloader's loadClass.
775 // For these classloaders, we ensure that the first requestor
776 // completes the load and other requestors wait for completion.
777 // case 3. UnsyncloadClass - don't use objectLocker
778 // With this flag, we allow parallel classloading of a
779 // class/classloader pair
780 // case4. Bootstrap classloader - don't own objectLocker
781 // This classloader supports parallelism at the classloader level,
782 // but only allows a single load of a class/classloader pair.
783 // No performance benefit and no deadlock issues.
784 // case 5. parallelCapable user level classloaders - without objectLocker
785 // Allow parallel classloading of a class/classloader pair
786
787 {
788 MutexLocker mu(SystemDictionary_lock, THREAD);
789 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
790 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
791 if (oldprobe) {
792 // only need check_seen_thread once, not on each loop
793 // 6341374 java/lang/Instrument with -Xcomp
794 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
795 throw_circularity_error = true;
796 } else {
797 // case 1: traditional: should never see load_in_progress.
798 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
799
800 // case 4: bootstrap classloader: prevent futile classloading,
801 // wait on first requestor
802 if (class_loader.is_null()) {
803 SystemDictionary_lock->wait();
804 } else {
805 // case 2: traditional with broken classloader lock. wait on first
806 // requestor.
807 double_lock_wait(lockObject, THREAD);
808 }
809 // Check if classloading completed while we were waiting
810 InstanceKlass* check = find_class(d_hash, name, dictionary);
811 if (check != NULL) {
812 // Klass is already loaded, so just return it
813 k = check;
814 class_has_been_loaded = true;
815 }
816 // check if other thread failed to load and cleaned up
817 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
818 }
819 }
820 }
821 }
822 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
823 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
824 // LOAD_INSTANCE in parallel
825
826 if (!throw_circularity_error && !class_has_been_loaded) {
827 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
828 load_instance_added = true;
829 // For class loaders that do not acquire the classloader object lock,
830 // if they did not catch another thread holding LOAD_INSTANCE,
831 // need a check analogous to the acquire ObjectLocker/find_class
832 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
833 // one final check if the load has already completed
834 // class loaders holding the ObjectLock shouldn't find the class here
835 InstanceKlass* check = find_class(d_hash, name, dictionary);
836 if (check != NULL) {
837 // Klass is already loaded, so return it after checking/adding protection domain
838 k = check;
839 class_has_been_loaded = true;
840 }
841 }
842 }
843
844 // must throw error outside of owning lock
845 if (throw_circularity_error) {
846 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
847 ResourceMark rm(THREAD);
848 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
849 }
850
851 if (!class_has_been_loaded) {
852
853 // Do actual loading
854 k = load_instance_class(name, class_loader, THREAD);
855
856 // For UnsyncloadClass only
857 // If they got a linkageError, check if a parallel class load succeeded.
858 // If it did, then for bytecode resolution the specification requires
859 // that we return the same result we did for the other thread, i.e. the
860 // successfully loaded InstanceKlass
861 // Should not get here for classloaders that support parallelism
862 // with the new cleaner mechanism, even with AllowParallelDefineClass
863 // Bootstrap goes through here to allow for an extra guarantee check
864 if (UnsyncloadClass || (class_loader.is_null())) {
865 if (k == NULL && HAS_PENDING_EXCEPTION
866 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
867 MutexLocker mu(SystemDictionary_lock, THREAD);
868 InstanceKlass* check = find_class(d_hash, name, dictionary);
869 if (check != NULL) {
870 // Klass is already loaded, so just use it
871 k = check;
872 CLEAR_PENDING_EXCEPTION;
873 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
874 }
875 }
876 }
877
878 // If everything was OK (no exceptions, no null return value), and
879 // class_loader is NOT the defining loader, do a little more bookkeeping.
880 if (!HAS_PENDING_EXCEPTION && k != NULL &&
881 k->class_loader() != class_loader()) {
882
883 check_constraints(d_hash, k, class_loader, false, THREAD);
884
885 // Need to check for a PENDING_EXCEPTION again; check_constraints
886 // can throw and doesn't use the CHECK macro.
887 if (!HAS_PENDING_EXCEPTION) {
888 { // Grabbing the Compile_lock prevents systemDictionary updates
889 // during compilations.
890 MutexLocker mu(Compile_lock, THREAD);
891 update_dictionary(d_hash, p_index, p_hash,
892 k, class_loader, THREAD);
893 }
894
895 if (JvmtiExport::should_post_class_load()) {
896 Thread *thread = THREAD;
897 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
898 JvmtiExport::post_class_load((JavaThread *) thread, k);
899 }
900 }
901 }
902 } // load_instance_class
903
904 if (load_instance_added == true) {
905 // clean up placeholder entries for LOAD_INSTANCE success or error
906 // This brackets the SystemDictionary updates for both defining
907 // and initiating loaders
908 MutexLocker mu(SystemDictionary_lock, THREAD);
909 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
910 SystemDictionary_lock->notify_all();
911 }
912 }
913
914 if (HAS_PENDING_EXCEPTION || k == NULL) {
915 return NULL;
916 }
917
918 post_class_load_event(&class_load_start_event, k, loader_data);
919
920 #ifdef ASSERT
921 {
922 ClassLoaderData* loader_data = k->class_loader_data();
923 MutexLocker mu(SystemDictionary_lock, THREAD);
924 Klass* kk = find_class(name, loader_data);
925 assert(kk == k, "should be present in dictionary");
926 }
927 #endif
928
929 // return if the protection domain in NULL
930 if (protection_domain() == NULL) return k;
931
932 // Check the protection domain has the right access
933 if (dictionary->is_valid_protection_domain(d_hash, name,
934 protection_domain)) {
935 return k;
936 }
937
938 // Verify protection domain. If it fails an exception is thrown
939 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
940
941 return k;
942 }
943
944
945 // This routine does not lock the system dictionary.
946 //
947 // Since readers don't hold a lock, we must make sure that system
948 // dictionary entries are only removed at a safepoint (when only one
949 // thread is running), and are added to in a safe way (all links must
950 // be updated in an MT-safe manner).
951 //
952 // Callers should be aware that an entry could be added just after
953 // _dictionary->bucket(index) is read here, so the caller will not see
954 // the new entry.
955
956 Klass* SystemDictionary::find(Symbol* class_name,
957 Handle class_loader,
958 Handle protection_domain,
959 TRAPS) {
960
961 // The result of this call should be consistent with the result
962 // of the call to resolve_instance_class_or_null().
963 // See evaluation 6790209 and 4474172 for more details.
964 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
965 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
966
967 if (loader_data == NULL) {
968 // If the ClassLoaderData has not been setup,
969 // then the class loader has no entries in the dictionary.
970 return NULL;
971 }
972
973 Dictionary* dictionary = loader_data->dictionary();
974 unsigned int d_hash = dictionary->compute_hash(class_name);
975 return dictionary->find(d_hash, class_name,
976 protection_domain);
977 }
978
979
980 // Look for a loaded instance or array klass by name. Do not do any loading.
981 // return NULL in case of error.
982 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
983 Handle class_loader,
984 Handle protection_domain,
985 TRAPS) {
986 Klass* k = NULL;
987 assert(class_name != NULL, "class name must be non NULL");
988
989 if (FieldType::is_array(class_name)) {
990 // The name refers to an array. Parse the name.
991 // dimension and object_key in FieldArrayInfo are assigned as a
992 // side-effect of this call
993 FieldArrayInfo fd;
994 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
995 if (t != T_OBJECT && t != T_VALUETYPE) {
996 k = Universe::typeArrayKlassObj(t);
997 } else {
998 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
999 }
1000 if (k != NULL) {
1001 k = k->array_klass_or_null(fd.dimension());
1002 }
1003 } else {
1004 k = find(class_name, class_loader, protection_domain, THREAD);
1005 }
1006 return k;
1007 }
1008
1009 // Note: this method is much like resolve_from_stream, but
1010 // does not publish the classes via the SystemDictionary.
1011 // Handles unsafe_DefineAnonymousClass and redefineclasses
1012 // RedefinedClasses do not add to the class hierarchy
1013 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1014 Handle class_loader,
1015 Handle protection_domain,
1016 ClassFileStream* st,
1017 const InstanceKlass* host_klass,
1018 GrowableArray<Handle>* cp_patches,
1019 TRAPS) {
1020
1021 EventClassLoad class_load_start_event;
1022
1023 ClassLoaderData* loader_data;
1024 if (host_klass != NULL) {
1025 // Create a new CLD for anonymous class, that uses the same class loader
1026 // as the host_klass
1027 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1028 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1029 } else {
1030 loader_data = ClassLoaderData::class_loader_data(class_loader());
1031 }
1032
1033 assert(st != NULL, "invariant");
1034 assert(st->need_verify(), "invariant");
1035
1036 // Parse stream and create a klass.
1037 // Note that we do this even though this klass might
1038 // already be present in the SystemDictionary, otherwise we would not
1039 // throw potential ClassFormatErrors.
1040
1041 InstanceKlass* k = KlassFactory::create_from_stream(st,
1042 class_name,
1043 loader_data,
1044 protection_domain,
1045 host_klass,
1046 cp_patches,
1047 CHECK_NULL);
1048
1049 if (host_klass != NULL && k != NULL) {
1050 // If it's anonymous, initialize it now, since nobody else will.
1051
1052 {
1053 MutexLocker mu_r(Compile_lock, THREAD);
1054
1055 // Add to class hierarchy, initialize vtables, and do possible
1056 // deoptimizations.
1057 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1058
1059 // But, do not add to dictionary.
1060
1061 // compiled code dependencies need to be validated anyway
1062 notice_modification();
1063 }
1064
1065 // Rewrite and patch constant pool here.
1066 k->link_class(CHECK_NULL);
1067 if (cp_patches != NULL) {
1068 k->constants()->patch_resolved_references(cp_patches);
1069 }
1070 k->eager_initialize(CHECK_NULL);
1071
1072 // notify jvmti
1073 if (JvmtiExport::should_post_class_load()) {
1074 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1075 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1076 }
1077
1078 post_class_load_event(&class_load_start_event, k, loader_data);
1079 }
1080 assert(host_klass != NULL || NULL == cp_patches,
1081 "cp_patches only found with host_klass");
1082
1083 return k;
1084 }
1085
1086 // Add a klass to the system from a stream (called by jni_DefineClass and
1087 // JVM_DefineClass).
1088 // Note: class_name can be NULL. In that case we do not know the name of
1089 // the class until we have parsed the stream.
1090
1091 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1092 Handle class_loader,
1093 Handle protection_domain,
1094 ClassFileStream* st,
1095 TRAPS) {
1096 #if INCLUDE_CDS
1097 ResourceMark rm(THREAD);
1098 if (DumpSharedSpaces && !class_loader.is_null() &&
1099 !UseAppCDS && strcmp(class_name->as_C_string(), "Unnamed") != 0) {
1100 // If AppCDS is not enabled, don't define the class at dump time (except for the "Unnamed"
1101 // class, which is used by MethodHandles).
1102 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
1103 }
1104 #endif
1105
1106 HandleMark hm(THREAD);
1107
1108 // Classloaders that support parallelism, e.g. bootstrap classloader,
1109 // or all classloaders with UnsyncloadClass do not acquire lock here
1110 bool DoObjectLock = true;
1111 if (is_parallelCapable(class_loader)) {
1112 DoObjectLock = false;
1113 }
1114
1115 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1116
1117 // Make sure we are synchronized on the class loader before we proceed
1118 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1119 check_loader_lock_contention(lockObject, THREAD);
1120 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1121
1122 assert(st != NULL, "invariant");
1123
1124 // Parse the stream and create a klass.
1125 // Note that we do this even though this klass might
1126 // already be present in the SystemDictionary, otherwise we would not
1127 // throw potential ClassFormatErrors.
1128 InstanceKlass* k = NULL;
1129
1130 #if INCLUDE_CDS
1131 if (!DumpSharedSpaces) {
1132 k = SystemDictionaryShared::lookup_from_stream(class_name,
1133 class_loader,
1134 protection_domain,
1135 st,
1136 CHECK_NULL);
1137 }
1138 #endif
1139
1140 if (k == NULL) {
1141 if (st->buffer() == NULL) {
1142 return NULL;
1143 }
1144 k = KlassFactory::create_from_stream(st,
1145 class_name,
1146 loader_data,
1147 protection_domain,
1148 NULL, // host_klass
1149 NULL, // cp_patches
1150 CHECK_NULL);
1151 }
1152
1153 assert(k != NULL, "no klass created");
1154 Symbol* h_name = k->name();
1155 assert(class_name == NULL || class_name == h_name, "name mismatch");
1156
1157 // Add class just loaded
1158 // If a class loader supports parallel classloading handle parallel define requests
1159 // find_or_define_instance_class may return a different InstanceKlass
1160 if (is_parallelCapable(class_loader)) {
1161 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1162 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1163 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1164 assert(defined_k != NULL, "Should have a klass if there's no exception");
1165 loader_data->add_to_deallocate_list(k);
1166 k = defined_k;
1167 }
1168 } else {
1169 define_instance_class(k, THREAD);
1170 }
1171
1172 // If defining the class throws an exception register 'k' for cleanup.
1173 if (HAS_PENDING_EXCEPTION) {
1174 assert(k != NULL, "Must have an instance klass here!");
1175 loader_data->add_to_deallocate_list(k);
1176 return NULL;
1177 }
1178
1179 // Make sure we have an entry in the SystemDictionary on success
1180 debug_only( {
1181 MutexLocker mu(SystemDictionary_lock, THREAD);
1182
1183 Klass* check = find_class(h_name, k->class_loader_data());
1184 assert(check == k, "should be present in the dictionary");
1185 } );
1186
1187 return k;
1188 }
1189
1190 #if INCLUDE_CDS
1191 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1192 int number_of_entries) {
1193 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1194 "bad shared dictionary size.");
1195 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1196 _shared_dictionary_size, t, number_of_entries);
1197 }
1198
1199
1200 // If there is a shared dictionary, then find the entry for the
1201 // given shared system class, if any.
1202
1203 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1204 if (shared_dictionary() != NULL) {
1205 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1206 int d_index = shared_dictionary()->hash_to_index(d_hash);
1207
1208 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1209 } else {
1210 return NULL;
1211 }
1212 }
1213
1214
1215 // Load a class from the shared spaces (found through the shared system
1216 // dictionary). Force the superclass and all interfaces to be loaded.
1217 // Update the class definition to include sibling classes and no
1218 // subclasses (yet). [Classes in the shared space are not part of the
1219 // object hierarchy until loaded.]
1220
1221 InstanceKlass* SystemDictionary::load_shared_class(
1222 Symbol* class_name, Handle class_loader, TRAPS) {
1223 InstanceKlass* ik = find_shared_class(class_name);
1224 // Make sure we only return the boot class for the NULL classloader.
1225 if (ik != NULL &&
1226 ik->is_shared_boot_class() && class_loader.is_null()) {
1227 Handle protection_domain;
1228 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1229 }
1230 return NULL;
1231 }
1232
1233 // Check if a shared class can be loaded by the specific classloader:
1234 //
1235 // NULL classloader:
1236 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1237 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1238 // be defined in an unnamed module.
1239 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1240 InstanceKlass* ik,
1241 Handle class_loader, TRAPS) {
1242 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1243 "Cannot use sharing if java.base is patched");
1244 ResourceMark rm;
1245 int path_index = ik->shared_classpath_index();
1246 ClassLoaderData* loader_data = class_loader_data(class_loader);
1247 if (path_index < 0) {
1248 // path_index < 0 indicates that the class is intended for a custom loader
1249 // and should not be loaded by boot/platform/app loaders
1250 if (loader_data->is_builtin_class_loader_data()) {
1251 return false;
1252 } else {
1253 return true;
1254 }
1255 }
1256 SharedClassPathEntry* ent =
1257 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1258 if (!Universe::is_module_initialized()) {
1259 assert(ent != NULL && ent->is_modules_image(),
1260 "Loading non-bootstrap classes before the module system is initialized");
1261 assert(class_loader.is_null(), "sanity");
1262 return true;
1263 }
1264 // Get the pkg_entry from the classloader
1265 TempNewSymbol pkg_name = NULL;
1266 PackageEntry* pkg_entry = NULL;
1267 ModuleEntry* mod_entry = NULL;
1268 const char* pkg_string = NULL;
1269 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1270 if (pkg_name != NULL) {
1271 pkg_string = pkg_name->as_C_string();
1272 if (loader_data != NULL) {
1273 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1274 }
1275 if (pkg_entry != NULL) {
1276 mod_entry = pkg_entry->module();
1277 }
1278 }
1279
1280 // If the archived class is from a module that has been patched at runtime,
1281 // the class cannot be loaded from the archive.
1282 if (mod_entry != NULL && mod_entry->is_patched()) {
1283 return false;
1284 }
1285
1286 if (class_loader.is_null()) {
1287 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1288 // The NULL classloader can load archived class originated from the
1289 // "modules" jimage and the -Xbootclasspath/a. For class from the
1290 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1291 // by the NULL classloader.
1292 if (mod_entry != NULL) {
1293 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1294 // ModuleEntry's location agrees with the archived class' origination.
1295 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1296 return true; // Module class from the "module" jimage
1297 }
1298 }
1299
1300 // If the archived class is not from the "module" jimage, the class can be
1301 // loaded by the NULL classloader if
1302 //
1303 // 1. the class is from the unamed package
1304 // 2. or, the class is not from a module defined in the NULL classloader
1305 // 3. or, the class is from an unamed module
1306 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1307 // the class is from the -Xbootclasspath/a
1308 if (pkg_string == NULL ||
1309 pkg_entry == NULL ||
1310 pkg_entry->in_unnamed_module()) {
1311 assert(mod_entry == NULL ||
1312 mod_entry == loader_data->unnamed_module(),
1313 "the unnamed module is not defined in the classloader");
1314 return true;
1315 }
1316 }
1317 return false;
1318 } else {
1319 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1320 ik, class_loader, pkg_string, pkg_name,
1321 pkg_entry, mod_entry, CHECK_(false));
1322 return res;
1323 }
1324 }
1325
1326 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1327 Handle class_loader,
1328 Handle protection_domain, TRAPS) {
1329
1330 if (ik != NULL) {
1331 Symbol* class_name = ik->name();
1332
1333 bool visible = is_shared_class_visible(
1334 class_name, ik, class_loader, CHECK_NULL);
1335 if (!visible) {
1336 return NULL;
1337 }
1338
1339 // Resolve the superclass and interfaces. They must be the same
1340 // as in dump time, because the layout of <ik> depends on
1341 // the specific layout of ik->super() and ik->local_interfaces().
1342 //
1343 // If unexpected superclass or interfaces are found, we cannot
1344 // load <ik> from the shared archive.
1345
1346 if (ik->super() != NULL) {
1347 Symbol* cn = ik->super()->name();
1348 Klass *s = resolve_super_or_fail(class_name, cn,
1349 class_loader, protection_domain, true, CHECK_NULL);
1350 if (s != ik->super()) {
1351 // The dynamically resolved super class is not the same as the one we used during dump time,
1352 // so we cannot use ik.
1353 return NULL;
1354 } else {
1355 assert(s->is_shared(), "must be");
1356 }
1357 }
1358
1359 Array<Klass*>* interfaces = ik->local_interfaces();
1360 int num_interfaces = interfaces->length();
1361 for (int index = 0; index < num_interfaces; index++) {
1362 Klass* k = interfaces->at(index);
1363 Symbol* name = k->name();
1364 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1365 if (k != i) {
1366 // The dynamically resolved interface class is not the same as the one we used during dump time,
1367 // so we cannot use ik.
1368 return NULL;
1369 } else {
1370 assert(i->is_shared(), "must be");
1371 }
1372 }
1373
1374 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1375 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1376 if (new_ik != NULL) {
1377 // The class is changed by CFLH. Return the new class. The shared class is
1378 // not used.
1379 return new_ik;
1380 }
1381
1382 // Adjust methods to recover missing data. They need addresses for
1383 // interpreter entry points and their default native method address
1384 // must be reset.
1385
1386 // Updating methods must be done under a lock so multiple
1387 // threads don't update these in parallel
1388 //
1389 // Shared classes are all currently loaded by either the bootstrap or
1390 // internal parallel class loaders, so this will never cause a deadlock
1391 // on a custom class loader lock.
1392
1393 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1394 {
1395 HandleMark hm(THREAD);
1396 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1397 check_loader_lock_contention(lockObject, THREAD);
1398 ObjectLocker ol(lockObject, THREAD, true);
1399 // prohibited package check assumes all classes loaded from archive call
1400 // restore_unshareable_info which calls ik->set_package()
1401 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1402 }
1403
1404 ik->print_class_load_logging(loader_data, NULL, NULL);
1405
1406 // For boot loader, ensure that GetSystemPackage knows that a class in this
1407 // package was loaded.
1408 if (class_loader.is_null()) {
1409 int path_index = ik->shared_classpath_index();
1410 ResourceMark rm;
1411 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1412 }
1413
1414 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1415 // Only dump the classes that can be stored into CDS archive
1416 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1417 ResourceMark rm(THREAD);
1418 classlist_file->print_cr("%s", ik->name()->as_C_string());
1419 classlist_file->flush();
1420 }
1421 }
1422
1423 // notify a class loaded from shared object
1424 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1425 }
1426
1427 ik->set_has_passed_fingerprint_check(false);
1428 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1429 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1430 uint64_t cds_fp = ik->get_stored_fingerprint();
1431 if (aot_fp != 0 && aot_fp == cds_fp) {
1432 // This class matches with a class saved in an AOT library
1433 ik->set_has_passed_fingerprint_check(true);
1434 } else {
1435 ResourceMark rm;
1436 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1437 }
1438 }
1439 return ik;
1440 }
1441
1442 void SystemDictionary::clear_invoke_method_table() {
1443 SymbolPropertyEntry* spe = NULL;
1444 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1445 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1446 while (p != NULL) {
1447 spe = p;
1448 p = p->next();
1449 _invoke_method_table->free_entry(spe);
1450 }
1451 }
1452 }
1453 #endif // INCLUDE_CDS
1454
1455 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1456
1457 if (class_loader.is_null()) {
1458 ResourceMark rm;
1459 PackageEntry* pkg_entry = NULL;
1460 bool search_only_bootloader_append = false;
1461 ClassLoaderData *loader_data = class_loader_data(class_loader);
1462
1463 // Find the package in the boot loader's package entry table.
1464 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1465 if (pkg_name != NULL) {
1466 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1467 }
1468
1469 // Prior to attempting to load the class, enforce the boot loader's
1470 // visibility boundaries.
1471 if (!Universe::is_module_initialized()) {
1472 // During bootstrapping, prior to module initialization, any
1473 // class attempting to be loaded must be checked against the
1474 // java.base packages in the boot loader's PackageEntryTable.
1475 // No class outside of java.base is allowed to be loaded during
1476 // this bootstrapping window.
1477 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1478 // Class is either in the unnamed package or in
1479 // a named package within the unnamed module. Either
1480 // case is outside of java.base, do not attempt to
1481 // load the class post java.base definition. If
1482 // java.base has not been defined, let the class load
1483 // and its package will be checked later by
1484 // ModuleEntryTable::verify_javabase_packages.
1485 if (ModuleEntryTable::javabase_defined()) {
1486 return NULL;
1487 }
1488 } else {
1489 // Check that the class' package is defined within java.base.
1490 ModuleEntry* mod_entry = pkg_entry->module();
1491 Symbol* mod_entry_name = mod_entry->name();
1492 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1493 return NULL;
1494 }
1495 }
1496 } else {
1497 // After the module system has been initialized, check if the class'
1498 // package is in a module defined to the boot loader.
1499 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1500 // Class is either in the unnamed package, in a named package
1501 // within a module not defined to the boot loader or in a
1502 // a named package within the unnamed module. In all cases,
1503 // limit visibility to search for the class only in the boot
1504 // loader's append path.
1505 search_only_bootloader_append = true;
1506 }
1507 }
1508
1509 // Prior to bootstrapping's module initialization, never load a class outside
1510 // of the boot loader's module path
1511 assert(Universe::is_module_initialized() ||
1512 !search_only_bootloader_append,
1513 "Attempt to load a class outside of boot loader's module path");
1514
1515 // Search the shared system dictionary for classes preloaded into the
1516 // shared spaces.
1517 InstanceKlass* k = NULL;
1518 {
1519 #if INCLUDE_CDS
1520 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1521 k = load_shared_class(class_name, class_loader, THREAD);
1522 #endif
1523 }
1524
1525 if (k == NULL) {
1526 // Use VM class loader
1527 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1528 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1529 }
1530
1531 // find_or_define_instance_class may return a different InstanceKlass
1532 if (k != NULL) {
1533 InstanceKlass* defined_k =
1534 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1535 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1536 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1537 assert(defined_k != NULL, "Should have a klass if there's no exception");
1538 loader_data->add_to_deallocate_list(k);
1539 k = defined_k;
1540 } else if (HAS_PENDING_EXCEPTION) {
1541 loader_data->add_to_deallocate_list(k);
1542 return NULL;
1543 }
1544 }
1545 return k;
1546 } else {
1547 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1548 ResourceMark rm(THREAD);
1549
1550 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1551 JavaThread* jt = (JavaThread*) THREAD;
1552
1553 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1554 ClassLoader::perf_app_classload_selftime(),
1555 ClassLoader::perf_app_classload_count(),
1556 jt->get_thread_stat()->perf_recursion_counts_addr(),
1557 jt->get_thread_stat()->perf_timers_addr(),
1558 PerfClassTraceTime::CLASS_LOAD);
1559
1560 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1561 // Translate to external class name format, i.e., convert '/' chars to '.'
1562 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1563
1564 JavaValue result(T_OBJECT);
1565
1566 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1567
1568 // Call public unsynchronized loadClass(String) directly for all class loaders
1569 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1570 // acquire a class-name based lock rather than the class loader object lock.
1571 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1572 // so the call to loadClassInternal() was not required.
1573 //
1574 // UnsyncloadClass flag means both call loadClass(String) and do
1575 // not acquire the class loader lock even for class loaders that are
1576 // not parallelCapable. This was a risky transitional
1577 // flag for diagnostic purposes only. It is risky to call
1578 // custom class loaders without synchronization.
1579 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1580 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1581 // Do NOT assume this will be supported in future releases.
1582 //
1583 // Added MustCallLoadClassInternal in case we discover in the field
1584 // a customer that counts on this call
1585 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1586 JavaCalls::call_special(&result,
1587 class_loader,
1588 spec_klass,
1589 vmSymbols::loadClassInternal_name(),
1590 vmSymbols::string_class_signature(),
1591 string,
1592 CHECK_NULL);
1593 } else {
1594 JavaCalls::call_virtual(&result,
1595 class_loader,
1596 spec_klass,
1597 vmSymbols::loadClass_name(),
1598 vmSymbols::string_class_signature(),
1599 string,
1600 CHECK_NULL);
1601 }
1602
1603 assert(result.get_type() == T_OBJECT, "just checking");
1604 oop obj = (oop) result.get_jobject();
1605
1606 // Primitive classes return null since forName() can not be
1607 // used to obtain any of the Class objects representing primitives or void
1608 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1609 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1610 // For user defined Java class loaders, check that the name returned is
1611 // the same as that requested. This check is done for the bootstrap
1612 // loader when parsing the class file.
1613 if (class_name == k->name()) {
1614 return k;
1615 }
1616 }
1617 // Class is not found or has the wrong name, return NULL
1618 return NULL;
1619 }
1620 }
1621
1622 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1623
1624 HandleMark hm(THREAD);
1625 ClassLoaderData* loader_data = k->class_loader_data();
1626 Handle class_loader_h(THREAD, loader_data->class_loader());
1627
1628 // for bootstrap and other parallel classloaders don't acquire lock,
1629 // use placeholder token
1630 // If a parallelCapable class loader calls define_instance_class instead of
1631 // find_or_define_instance_class to get here, we have a timing
1632 // hole with systemDictionary updates and check_constraints
1633 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1634 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1635 compute_loader_lock_object(class_loader_h, THREAD)),
1636 "define called without lock");
1637 }
1638
1639 // Check class-loading constraints. Throw exception if violation is detected.
1640 // Grabs and releases SystemDictionary_lock
1641 // The check_constraints/find_class call and update_dictionary sequence
1642 // must be "atomic" for a specific class/classloader pair so we never
1643 // define two different instanceKlasses for that class/classloader pair.
1644 // Existing classloaders will call define_instance_class with the
1645 // classloader lock held
1646 // Parallel classloaders will call find_or_define_instance_class
1647 // which will require a token to perform the define class
1648 Symbol* name_h = k->name();
1649 Dictionary* dictionary = loader_data->dictionary();
1650 unsigned int d_hash = dictionary->compute_hash(name_h);
1651 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1652
1653 // Register class just loaded with class loader (placed in Vector)
1654 // Note we do this before updating the dictionary, as this can
1655 // fail with an OutOfMemoryError (if it does, we will *not* put this
1656 // class in the dictionary and will not update the class hierarchy).
1657 // JVMTI FollowReferences needs to find the classes this way.
1658 if (k->class_loader() != NULL) {
1659 methodHandle m(THREAD, Universe::loader_addClass_method());
1660 JavaValue result(T_VOID);
1661 JavaCallArguments args(class_loader_h);
1662 args.push_oop(Handle(THREAD, k->java_mirror()));
1663 JavaCalls::call(&result, m, &args, CHECK);
1664 }
1665
1666 // Add the new class. We need recompile lock during update of CHA.
1667 {
1668 unsigned int p_hash = placeholders()->compute_hash(name_h);
1669 int p_index = placeholders()->hash_to_index(p_hash);
1670
1671 MutexLocker mu_r(Compile_lock, THREAD);
1672
1673 // Add to class hierarchy, initialize vtables, and do possible
1674 // deoptimizations.
1675 add_to_hierarchy(k, CHECK); // No exception, but can block
1676
1677 // Add to systemDictionary - so other classes can see it.
1678 // Grabs and releases SystemDictionary_lock
1679 update_dictionary(d_hash, p_index, p_hash,
1680 k, class_loader_h, THREAD);
1681 }
1682 k->eager_initialize(THREAD);
1683
1684 // notify jvmti
1685 if (JvmtiExport::should_post_class_load()) {
1686 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1687 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1688
1689 }
1690 class_define_event(k, loader_data);
1691 }
1692
1693 // Support parallel classloading
1694 // All parallel class loaders, including bootstrap classloader
1695 // lock a placeholder entry for this class/class_loader pair
1696 // to allow parallel defines of different classes for this class loader
1697 // With AllowParallelDefine flag==true, in case they do not synchronize around
1698 // FindLoadedClass/DefineClass, calls, we check for parallel
1699 // loading for them, wait if a defineClass is in progress
1700 // and return the initial requestor's results
1701 // This flag does not apply to the bootstrap classloader.
1702 // With AllowParallelDefine flag==false, call through to define_instance_class
1703 // which will throw LinkageError: duplicate class definition.
1704 // False is the requested default.
1705 // For better performance, the class loaders should synchronize
1706 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1707 // potentially waste time reading and parsing the bytestream.
1708 // Note: VM callers should ensure consistency of k/class_name,class_loader
1709 // Be careful when modifying this code: once you have run
1710 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1711 // you need to find_and_remove it before returning.
1712 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1713 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1714 InstanceKlass* k, TRAPS) {
1715
1716 Symbol* name_h = k->name(); // passed in class_name may be null
1717 ClassLoaderData* loader_data = class_loader_data(class_loader);
1718 Dictionary* dictionary = loader_data->dictionary();
1719
1720 unsigned int d_hash = dictionary->compute_hash(name_h);
1721
1722 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1723 unsigned int p_hash = placeholders()->compute_hash(name_h);
1724 int p_index = placeholders()->hash_to_index(p_hash);
1725 PlaceholderEntry* probe;
1726
1727 {
1728 MutexLocker mu(SystemDictionary_lock, THREAD);
1729 // First check if class already defined
1730 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1731 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1732 if (check != NULL) {
1733 return check;
1734 }
1735 }
1736
1737 // Acquire define token for this class/classloader
1738 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1739 // Wait if another thread defining in parallel
1740 // All threads wait - even those that will throw duplicate class: otherwise
1741 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1742 // if other thread has not finished updating dictionary
1743 while (probe->definer() != NULL) {
1744 SystemDictionary_lock->wait();
1745 }
1746 // Only special cases allow parallel defines and can use other thread's results
1747 // Other cases fall through, and may run into duplicate defines
1748 // caught by finding an entry in the SystemDictionary
1749 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1750 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1751 SystemDictionary_lock->notify_all();
1752 #ifdef ASSERT
1753 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1754 assert(check != NULL, "definer missed recording success");
1755 #endif
1756 return probe->instance_klass();
1757 } else {
1758 // This thread will define the class (even if earlier thread tried and had an error)
1759 probe->set_definer(THREAD);
1760 }
1761 }
1762
1763 define_instance_class(k, THREAD);
1764
1765 Handle linkage_exception = Handle(); // null handle
1766
1767 // definer must notify any waiting threads
1768 {
1769 MutexLocker mu(SystemDictionary_lock, THREAD);
1770 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1771 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1772 if (probe != NULL) {
1773 if (HAS_PENDING_EXCEPTION) {
1774 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1775 CLEAR_PENDING_EXCEPTION;
1776 } else {
1777 probe->set_instance_klass(k);
1778 }
1779 probe->set_definer(NULL);
1780 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1781 SystemDictionary_lock->notify_all();
1782 }
1783 }
1784
1785 // Can't throw exception while holding lock due to rank ordering
1786 if (linkage_exception() != NULL) {
1787 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1788 }
1789
1790 return k;
1791 }
1792
1793 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1794 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1795 if (class_loader.is_null()) {
1796 return Handle(THREAD, _system_loader_lock_obj);
1797 } else {
1798 return class_loader;
1799 }
1800 }
1801
1802 // This method is added to check how often we have to wait to grab loader
1803 // lock. The results are being recorded in the performance counters defined in
1804 // ClassLoader::_sync_systemLoaderLockContentionRate and
1805 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1806 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1807 if (!UsePerfData) {
1808 return;
1809 }
1810
1811 assert(!loader_lock.is_null(), "NULL lock object");
1812
1813 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1814 == ObjectSynchronizer::owner_other) {
1815 // contention will likely happen, so increment the corresponding
1816 // contention counter.
1817 if (loader_lock() == _system_loader_lock_obj) {
1818 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1819 } else {
1820 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1821 }
1822 }
1823 }
1824
1825 // ----------------------------------------------------------------------------
1826 // Lookup
1827
1828 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1829 Symbol* class_name,
1830 Dictionary* dictionary) {
1831 assert_locked_or_safepoint(SystemDictionary_lock);
1832 int index = dictionary->hash_to_index(hash);
1833 return dictionary->find_class(index, hash, class_name);
1834 }
1835
1836
1837 // Basic find on classes in the midst of being loaded
1838 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1839 ClassLoaderData* loader_data) {
1840 assert_locked_or_safepoint(SystemDictionary_lock);
1841 unsigned int p_hash = placeholders()->compute_hash(class_name);
1842 int p_index = placeholders()->hash_to_index(p_hash);
1843 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1844 }
1845
1846
1847 // Used for assertions and verification only
1848 // Precalculating the hash and index is an optimization because there are many lookups
1849 // before adding the class.
1850 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1851 assert_locked_or_safepoint(SystemDictionary_lock);
1852 #ifndef ASSERT
1853 guarantee(VerifyBeforeGC ||
1854 VerifyDuringGC ||
1855 VerifyBeforeExit ||
1856 VerifyDuringStartup ||
1857 VerifyAfterGC, "too expensive");
1858 #endif
1859
1860 Dictionary* dictionary = loader_data->dictionary();
1861 unsigned int d_hash = dictionary->compute_hash(class_name);
1862 return find_class(d_hash, class_name, dictionary);
1863 }
1864
1865
1866 // ----------------------------------------------------------------------------
1867 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1868 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1869 // before a new class is used.
1870
1871 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1872 assert(k != NULL, "just checking");
1873 assert_locked_or_safepoint(Compile_lock);
1874
1875 // Link into hierachy. Make sure the vtables are initialized before linking into
1876 k->append_to_sibling_list(); // add to superklass/sibling list
1877 k->process_interfaces(THREAD); // handle all "implements" declarations
1878 k->set_init_state(InstanceKlass::loaded);
1879 // Now flush all code that depended on old class hierarchy.
1880 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1881 // Also, first reinitialize vtable because it may have gotten out of synch
1882 // while the new class wasn't connected to the class hierarchy.
1883 CodeCache::flush_dependents_on(k);
1884 }
1885
1886 // ----------------------------------------------------------------------------
1887 // GC support
1888
1889 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1890 roots_oops_do(blk, NULL);
1891 }
1892
1893
1894 #ifdef ASSERT
1895 class VerifySDReachableAndLiveClosure : public OopClosure {
1896 private:
1897 BoolObjectClosure* _is_alive;
1898
1899 template <class T> void do_oop_work(T* p) {
1900 oop obj = oopDesc::load_decode_heap_oop(p);
1901 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1902 }
1903
1904 public:
1905 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1906
1907 virtual void do_oop(oop* p) { do_oop_work(p); }
1908 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1909 };
1910 #endif
1911
1912 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1913 // Note: anonymous classes are not in the SD.
1914 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1915 GCTimer* gc_timer,
1916 bool do_cleaning) {
1917
1918
1919 bool unloading_occurred;
1920 {
1921 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1922
1923 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1924 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1925 do_cleaning);
1926 }
1927
1928 if (unloading_occurred) {
1929 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1930 constraints()->purge_loader_constraints();
1931 resolution_errors()->purge_resolution_errors();
1932 }
1933
1934 {
1935 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1936 // Oops referenced by the protection domain cache table may get unreachable independently
1937 // of the class loader (eg. cached protection domain oops). So we need to
1938 // explicitly unlink them here.
1939 _pd_cache_table->unlink(is_alive);
1940
1941 #ifdef ASSERT
1942 VerifySDReachableAndLiveClosure cl(is_alive);
1943 _pd_cache_table->oops_do(&cl);
1944 #endif
1945 }
1946
1947 if (do_cleaning) {
1948 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1949 ResolvedMethodTable::unlink(is_alive);
1950 }
1951
1952 return unloading_occurred;
1953 }
1954
1955 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1956 strong->do_oop(&_java_system_loader);
1957 strong->do_oop(&_java_platform_loader);
1958 strong->do_oop(&_system_loader_lock_obj);
1959 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1960
1961 // Do strong roots marking if the closures are the same.
1962 if (strong == weak || !ClassUnloading) {
1963 // Only the protection domain oops contain references into the heap. Iterate
1964 // over all of them.
1965 _pd_cache_table->oops_do(strong);
1966 } else {
1967 if (weak != NULL) {
1968 _pd_cache_table->oops_do(weak);
1969 }
1970 }
1971
1972 // Visit extra methods
1973 invoke_method_table()->oops_do(strong);
1974
1975 if (weak != NULL) {
1976 ResolvedMethodTable::oops_do(weak);
1977 }
1978 }
1979
1980 void SystemDictionary::oops_do(OopClosure* f) {
1981 f->do_oop(&_java_system_loader);
1982 f->do_oop(&_java_platform_loader);
1983 f->do_oop(&_system_loader_lock_obj);
1984 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1985
1986 // Only the protection domain oops contain references into the heap. Iterate
1987 // over all of them.
1988 _pd_cache_table->oops_do(f);
1989
1990 // Visit extra methods
1991 invoke_method_table()->oops_do(f);
1992
1993 ResolvedMethodTable::oops_do(f);
1994 }
1995
1996 // CDS: scan and relocate all classes in the system dictionary.
1997 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1998 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1999 }
2000
2001 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
2002 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
2003 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
2004 it->push(well_known_klass_addr((WKID)id));
2005 }
2006 }
2007
2008 void SystemDictionary::methods_do(void f(Method*)) {
2009 // Walk methods in loaded classes
2010 ClassLoaderDataGraph::methods_do(f);
2011 // Walk method handle intrinsics
2012 invoke_method_table()->methods_do(f);
2013 }
2014
2015 class RemoveClassesClosure : public CLDClosure {
2016 public:
2017 void do_cld(ClassLoaderData* cld) {
2018 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
2019 cld->dictionary()->remove_classes_in_error_state();
2020 }
2021 }
2022 };
2023
2024 void SystemDictionary::remove_classes_in_error_state() {
2025 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
2026 RemoveClassesClosure rcc;
2027 ClassLoaderDataGraph::cld_do(&rcc);
2028 }
2029
2030 // ----------------------------------------------------------------------------
2031 // Lazily load klasses
2032
2033 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2034 // if multiple threads calling this function, only one thread will load
2035 // the class. The other threads will find the loaded version once the
2036 // class is loaded.
2037 Klass* aos = _abstract_ownable_synchronizer_klass;
2038 if (aos == NULL) {
2039 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2040 // Force a fence to prevent any read before the write completes
2041 OrderAccess::fence();
2042 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2043 }
2044 }
2045
2046 // ----------------------------------------------------------------------------
2047 // Initialization
2048
2049 void SystemDictionary::initialize(TRAPS) {
2050 // Allocate arrays
2051 _placeholders = new PlaceholderTable(_placeholder_table_size);
2052 _number_of_modifications = 0;
2053 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2054 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2055 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2056 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2057
2058 // Allocate private object used as system class loader lock
2059 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2060 // Initialize basic classes
2061 initialize_preloaded_classes(CHECK);
2062 }
2063
2064 // Compact table of directions on the initialization of klasses:
2065 static const short wk_init_info[] = {
2066 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2067 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2068 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2069 | (int)SystemDictionary::option ),
2070 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2071 #undef WK_KLASS_INIT_INFO
2072 0
2073 };
2074
2075 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2076 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2077 int info = wk_init_info[id - FIRST_WKID];
2078 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2079 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2080 InstanceKlass** klassp = &_well_known_klasses[id];
2081
2082 bool must_load;
2083 #if INCLUDE_JVMCI
2084 if (EnableJVMCI) {
2085 // If JVMCI is enabled we require its classes to be found.
2086 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2087 } else
2088 #endif
2089 {
2090 must_load = (init_opt < SystemDictionary::Opt);
2091 }
2092
2093 if (init_opt == SystemDictionary::ValhallaClasses) {
2094 if (EnableValhalla || EnableMVT) {
2095 must_load = true;
2096 } else {
2097 return false;
2098 }
2099 } else if (init_opt == SystemDictionary::MVTClasses) {
2100 if (EnableMVT) {
2101 must_load = true;
2102 } else {
2103 return false;
2104 }
2105 }
2106
2107 if ((*klassp) == NULL) {
2108 Klass* k;
2109 if (must_load) {
2110 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2111 } else {
2112 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2113 }
2114 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2115 }
2116 return ((*klassp) != NULL);
2117 }
2118
2119 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2120 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2121 for (int id = (int)start_id; id < (int)limit_id; id++) {
2122 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2123 int info = wk_init_info[id - FIRST_WKID];
2124 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2125 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2126
2127 initialize_wk_klass((WKID)id, opt, CHECK);
2128 }
2129
2130 // move the starting value forward to the limit:
2131 start_id = limit_id;
2132 }
2133
2134 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2135 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2136
2137 // Create the ModuleEntry for java.base. This call needs to be done here,
2138 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2139 ClassLoader::classLoader_init2(CHECK);
2140
2141 // Preload commonly used klasses
2142 WKID scan = FIRST_WKID;
2143 // first do Object, then String, Class
2144 #if INCLUDE_CDS
2145 if (UseSharedSpaces) {
2146 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2147 // Initialize the constant pool for the Object_class
2148 Object_klass()->constants()->restore_unshareable_info(CHECK);
2149 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2150 } else
2151 #endif
2152 {
2153 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2154 }
2155
2156 // Calculate offsets for String and Class classes since they are loaded and
2157 // can be used after this point.
2158 java_lang_String::compute_offsets();
2159 java_lang_Class::compute_offsets();
2160
2161 // Fixup mirrors for classes loaded before java.lang.Class.
2162 // These calls iterate over the objects currently in the perm gen
2163 // so calling them at this point is matters (not before when there
2164 // are fewer objects and not later after there are more objects
2165 // in the perm gen.
2166 Universe::initialize_basic_type_mirrors(CHECK);
2167 Universe::fixup_mirrors(CHECK);
2168
2169 // do a bunch more:
2170 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2171
2172 // Preload ref klasses and set reference types
2173 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2174 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2175
2176 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2177 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2178 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2179 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2180 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2181
2182 // JSR 292 classes
2183 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2184 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2185 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2186 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2187 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2188
2189 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2190 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2191 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2192 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2193 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2194 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2195 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2196 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2197 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2198 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2199
2200 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2201 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2202 _has_loadClassInternal = (method != NULL);
2203 }
2204 { // Compute whether we should use checkPackageAccess or NOT
2205 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2206 _has_checkPackageAccess = (method != NULL);
2207 }
2208 }
2209
2210 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2211 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2212 BasicType SystemDictionary::box_klass_type(Klass* k) {
2213 assert(k != NULL, "");
2214 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2215 if (_box_klasses[i] == k)
2216 return (BasicType)i;
2217 }
2218 return T_OBJECT;
2219 }
2220
2221 // Constraints on class loaders. The details of the algorithm can be
2222 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2223 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2224 // that the dictionary needs to maintain a set of contraints that
2225 // must be satisfied by all classes in the dictionary.
2226 // if defining is true, then LinkageError if already in dictionary
2227 // if initiating loader, then ok if InstanceKlass matches existing entry
2228
2229 void SystemDictionary::check_constraints(unsigned int d_hash,
2230 InstanceKlass* k,
2231 Handle class_loader, bool defining,
2232 TRAPS) {
2233 const char *linkage_error1 = NULL;
2234 const char *linkage_error2 = NULL;
2235 {
2236 Symbol* name = k->name();
2237 ClassLoaderData *loader_data = class_loader_data(class_loader);
2238
2239 MutexLocker mu(SystemDictionary_lock, THREAD);
2240
2241 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2242 if (check != NULL) {
2243 // if different InstanceKlass - duplicate class definition,
2244 // else - ok, class loaded by a different thread in parallel,
2245 // we should only have found it if it was done loading and ok to use
2246 // dictionary only holds instance classes, placeholders
2247 // also holds array classes
2248
2249 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2250 if ((defining == true) || (k != check)) {
2251 linkage_error1 = "loader (instance of ";
2252 linkage_error2 = "): attempted duplicate class definition for name: \"";
2253 } else {
2254 return;
2255 }
2256 }
2257
2258 #ifdef ASSERT
2259 Symbol* ph_check = find_placeholder(name, loader_data);
2260 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2261 #endif
2262
2263 if (linkage_error1 == NULL) {
2264 if (constraints()->check_or_update(k, class_loader, name) == false) {
2265 linkage_error1 = "loader constraint violation: loader (instance of ";
2266 linkage_error2 = ") previously initiated loading for a different type with name \"";
2267 }
2268 }
2269 }
2270
2271 // Throw error now if needed (cannot throw while holding
2272 // SystemDictionary_lock because of rank ordering)
2273
2274 if (linkage_error1) {
2275 ResourceMark rm(THREAD);
2276 const char* class_loader_name = loader_name(class_loader());
2277 char* type_name = k->name()->as_C_string();
2278 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2279 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2280 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2281 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2282 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2283 }
2284 }
2285
2286
2287 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2288 // have been called.
2289 void SystemDictionary::update_dictionary(unsigned int d_hash,
2290 int p_index, unsigned int p_hash,
2291 InstanceKlass* k,
2292 Handle class_loader,
2293 TRAPS) {
2294 // Compile_lock prevents systemDictionary updates during compilations
2295 assert_locked_or_safepoint(Compile_lock);
2296 Symbol* name = k->name();
2297 ClassLoaderData *loader_data = class_loader_data(class_loader);
2298
2299 {
2300 MutexLocker mu1(SystemDictionary_lock, THREAD);
2301
2302 // See whether biased locking is enabled and if so set it for this
2303 // klass.
2304 // Note that this must be done past the last potential blocking
2305 // point / safepoint. We enable biased locking lazily using a
2306 // VM_Operation to iterate the SystemDictionary and installing the
2307 // biasable mark word into each InstanceKlass's prototype header.
2308 // To avoid race conditions where we accidentally miss enabling the
2309 // optimization for one class in the process of being added to the
2310 // dictionary, we must not safepoint after the test of
2311 // BiasedLocking::enabled().
2312 if (UseBiasedLocking && BiasedLocking::enabled()) {
2313 // Set biased locking bit for all loaded classes; it will be
2314 // cleared if revocation occurs too often for this type
2315 // NOTE that we must only do this when the class is initally
2316 // defined, not each time it is referenced from a new class loader
2317 if (k->class_loader() == class_loader()) {
2318 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2319 }
2320 }
2321
2322 // Make a new dictionary entry.
2323 Dictionary* dictionary = loader_data->dictionary();
2324 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2325 if (sd_check == NULL) {
2326 dictionary->add_klass(d_hash, name, k);
2327 notice_modification();
2328 }
2329 #ifdef ASSERT
2330 sd_check = find_class(d_hash, name, dictionary);
2331 assert (sd_check != NULL, "should have entry in dictionary");
2332 // Note: there may be a placeholder entry: for circularity testing
2333 // or for parallel defines
2334 #endif
2335 SystemDictionary_lock->notify_all();
2336 }
2337 }
2338
2339
2340 // Try to find a class name using the loader constraints. The
2341 // loader constraints might know about a class that isn't fully loaded
2342 // yet and these will be ignored.
2343 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2344 Symbol* class_name, Handle class_loader, TRAPS) {
2345
2346 // First see if it has been loaded directly.
2347 // Force the protection domain to be null. (This removes protection checks.)
2348 Handle no_protection_domain;
2349 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2350 no_protection_domain, CHECK_NULL);
2351 if (klass != NULL)
2352 return klass;
2353
2354 // Now look to see if it has been loaded elsewhere, and is subject to
2355 // a loader constraint that would require this loader to return the
2356 // klass that is already loaded.
2357 if (FieldType::is_array(class_name)) {
2358 // For array classes, their Klass*s are not kept in the
2359 // constraint table. The element Klass*s are.
2360 FieldArrayInfo fd;
2361 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2362 if (t != T_OBJECT && t != T_VALUETYPE) {
2363 klass = Universe::typeArrayKlassObj(t);
2364 } else {
2365 MutexLocker mu(SystemDictionary_lock, THREAD);
2366 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2367 }
2368 // If element class already loaded, allocate array klass
2369 if (klass != NULL) {
2370 klass = klass->array_klass_or_null(fd.dimension());
2371 }
2372 } else {
2373 MutexLocker mu(SystemDictionary_lock, THREAD);
2374 // Non-array classes are easy: simply check the constraint table.
2375 klass = constraints()->find_constrained_klass(class_name, class_loader);
2376 }
2377
2378 return klass;
2379 }
2380
2381
2382 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2383 Handle class_loader1,
2384 Handle class_loader2,
2385 Thread* THREAD) {
2386 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2387 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2388
2389 Symbol* constraint_name = NULL;
2390 if (!FieldType::is_array(class_name)) {
2391 constraint_name = class_name;
2392 } else {
2393 // For array classes, their Klass*s are not kept in the
2394 // constraint table. The element classes are.
2395 FieldArrayInfo fd;
2396 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2397 // primitive types always pass
2398 if (t != T_OBJECT) {
2399 return true;
2400 } else {
2401 constraint_name = fd.object_key();
2402 }
2403 }
2404
2405 Dictionary* dictionary1 = loader_data1->dictionary();
2406 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2407
2408 Dictionary* dictionary2 = loader_data2->dictionary();
2409 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2410
2411 {
2412 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2413 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2414 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2415 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2416 klass2, class_loader2);
2417 }
2418 }
2419
2420 // Add entry to resolution error table to record the error when the first
2421 // attempt to resolve a reference to a class has failed.
2422 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2423 Symbol* error, Symbol* message) {
2424 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2425 int index = resolution_errors()->hash_to_index(hash);
2426 {
2427 MutexLocker ml(SystemDictionary_lock, Thread::current());
2428 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2429 }
2430 }
2431
2432 // Delete a resolution error for RedefineClasses for a constant pool is going away
2433 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2434 resolution_errors()->delete_entry(pool);
2435 }
2436
2437 // Lookup resolution error table. Returns error if found, otherwise NULL.
2438 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2439 Symbol** message) {
2440 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2441 int index = resolution_errors()->hash_to_index(hash);
2442 {
2443 MutexLocker ml(SystemDictionary_lock, Thread::current());
2444 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2445 if (entry != NULL) {
2446 *message = entry->message();
2447 return entry->error();
2448 } else {
2449 return NULL;
2450 }
2451 }
2452 }
2453
2454
2455 // Signature constraints ensure that callers and callees agree about
2456 // the meaning of type names in their signatures. This routine is the
2457 // intake for constraints. It collects them from several places:
2458 //
2459 // * LinkResolver::resolve_method (if check_access is true) requires
2460 // that the resolving class (the caller) and the defining class of
2461 // the resolved method (the callee) agree on each type in the
2462 // method's signature.
2463 //
2464 // * LinkResolver::resolve_interface_method performs exactly the same
2465 // checks.
2466 //
2467 // * LinkResolver::resolve_field requires that the constant pool
2468 // attempting to link to a field agree with the field's defining
2469 // class about the type of the field signature.
2470 //
2471 // * klassVtable::initialize_vtable requires that, when a class
2472 // overrides a vtable entry allocated by a superclass, that the
2473 // overriding method (i.e., the callee) agree with the superclass
2474 // on each type in the method's signature.
2475 //
2476 // * klassItable::initialize_itable requires that, when a class fills
2477 // in its itables, for each non-abstract method installed in an
2478 // itable, the method (i.e., the callee) agree with the interface
2479 // on each type in the method's signature.
2480 //
2481 // All those methods have a boolean (check_access, checkconstraints)
2482 // which turns off the checks. This is used from specialized contexts
2483 // such as bootstrapping, dumping, and debugging.
2484 //
2485 // No direct constraint is placed between the class and its
2486 // supertypes. Constraints are only placed along linked relations
2487 // between callers and callees. When a method overrides or implements
2488 // an abstract method in a supertype (superclass or interface), the
2489 // constraints are placed as if the supertype were the caller to the
2490 // overriding method. (This works well, since callers to the
2491 // supertype have already established agreement between themselves and
2492 // the supertype.) As a result of all this, a class can disagree with
2493 // its supertype about the meaning of a type name, as long as that
2494 // class neither calls a relevant method of the supertype, nor is
2495 // called (perhaps via an override) from the supertype.
2496 //
2497 //
2498 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2499 //
2500 // Make sure all class components (including arrays) in the given
2501 // signature will be resolved to the same class in both loaders.
2502 // Returns the name of the type that failed a loader constraint check, or
2503 // NULL if no constraint failed. No exception except OOME is thrown.
2504 // Arrays are not added to the loader constraint table, their elements are.
2505 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2506 Handle loader1, Handle loader2,
2507 bool is_method, TRAPS) {
2508 // Nothing to do if loaders are the same.
2509 if (loader1() == loader2()) {
2510 return NULL;
2511 }
2512
2513 SignatureStream sig_strm(signature, is_method);
2514 while (!sig_strm.is_done()) {
2515 if (sig_strm.is_object()) {
2516 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2517 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2518 return sig;
2519 }
2520 }
2521 sig_strm.next();
2522 }
2523 return NULL;
2524 }
2525
2526
2527 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2528 Symbol* signature,
2529 TRAPS) {
2530 methodHandle empty;
2531 assert(MethodHandles::is_signature_polymorphic(iid) &&
2532 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2533 iid != vmIntrinsics::_invokeGeneric,
2534 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2535
2536 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2537 int index = invoke_method_table()->hash_to_index(hash);
2538 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2539 methodHandle m;
2540 if (spe == NULL || spe->method() == NULL) {
2541 spe = NULL;
2542 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2543 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2544 if (!Arguments::is_interpreter_only()) {
2545 // Generate a compiled form of the MH intrinsic.
2546 AdapterHandlerLibrary::create_native_wrapper(m);
2547 // Check if have the compiled code.
2548 if (!m->has_compiled_code()) {
2549 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2550 "Out of space in CodeCache for method handle intrinsic", empty);
2551 }
2552 }
2553 // Now grab the lock. We might have to throw away the new method,
2554 // if a racing thread has managed to install one at the same time.
2555 {
2556 MutexLocker ml(SystemDictionary_lock, THREAD);
2557 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2558 if (spe == NULL)
2559 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2560 if (spe->method() == NULL)
2561 spe->set_method(m());
2562 }
2563 }
2564
2565 assert(spe != NULL && spe->method() != NULL, "");
2566 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2567 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2568 "MH intrinsic invariant");
2569 return spe->method();
2570 }
2571
2572 // Helper for unpacking the return value from linkMethod and linkCallSite.
2573 static methodHandle unpack_method_and_appendix(Handle mname,
2574 Klass* accessing_klass,
2575 objArrayHandle appendix_box,
2576 Handle* appendix_result,
2577 TRAPS) {
2578 methodHandle empty;
2579 if (mname.not_null()) {
2580 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2581 if (m != NULL) {
2582 oop appendix = appendix_box->obj_at(0);
2583 if (TraceMethodHandles) {
2584 #ifndef PRODUCT
2585 ttyLocker ttyl;
2586 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2587 m->print();
2588 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2589 tty->cr();
2590 #endif //PRODUCT
2591 }
2592 (*appendix_result) = Handle(THREAD, appendix);
2593 // the target is stored in the cpCache and if a reference to this
2594 // MethodName is dropped we need a way to make sure the
2595 // class_loader containing this method is kept alive.
2596 // FIXME: the appendix might also preserve this dependency.
2597 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2598 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2599 return methodHandle(THREAD, m);
2600 }
2601 }
2602 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2603 return empty;
2604 }
2605
2606 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2607 Symbol* name,
2608 Symbol* signature,
2609 Klass* accessing_klass,
2610 Handle *appendix_result,
2611 Handle *method_type_result,
2612 TRAPS) {
2613 methodHandle empty;
2614 assert(THREAD->can_call_java() ,"");
2615 Handle method_type =
2616 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2617
2618 int ref_kind = JVM_REF_invokeVirtual;
2619 oop name_oop = StringTable::intern(name, CHECK_(empty));
2620 Handle name_str (THREAD, name_oop);
2621 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2622 assert(appendix_box->obj_at(0) == NULL, "");
2623
2624 // This should not happen. JDK code should take care of that.
2625 if (accessing_klass == NULL || method_type.is_null()) {
2626 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2627 }
2628
2629 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2630 JavaCallArguments args;
2631 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2632 args.push_int(ref_kind);
2633 args.push_oop(Handle(THREAD, klass->java_mirror()));
2634 args.push_oop(name_str);
2635 args.push_oop(method_type);
2636 args.push_oop(appendix_box);
2637 JavaValue result(T_OBJECT);
2638 JavaCalls::call_static(&result,
2639 SystemDictionary::MethodHandleNatives_klass(),
2640 vmSymbols::linkMethod_name(),
2641 vmSymbols::linkMethod_signature(),
2642 &args, CHECK_(empty));
2643 Handle mname(THREAD, (oop) result.get_jobject());
2644 (*method_type_result) = method_type;
2645 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2646 }
2647
2648 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2649 // We must ensure that all class loaders everywhere will reach this class, for any client.
2650 // This is a safe bet for public classes in java.lang, such as Object and String.
2651 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2652 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2653 static bool is_always_visible_class(oop mirror) {
2654 Klass* klass = java_lang_Class::as_Klass(mirror);
2655 if (klass->is_objArray_klass()) {
2656 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2657 }
2658 if (klass->is_typeArray_klass()) {
2659 return true; // primitive array
2660 }
2661 assert(klass->is_instance_klass(), "%s", klass->external_name());
2662 return klass->is_public() &&
2663 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2664 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2665 }
2666
2667
2668 // Return the Java mirror (java.lang.Class instance) for a single-character
2669 // descriptor. This result, when available, is the same as produced by the
2670 // heavier API point of the same name that takes a Symbol.
2671 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2672 return java_lang_Class::primitive_mirror(char2type(signature_char));
2673 }
2674
2675 // Find or construct the Java mirror (java.lang.Class instance) for a
2676 // for the given field type signature, as interpreted relative to the
2677 // given class loader. Handles primitives, void, references, arrays,
2678 // and all other reflectable types, except method types.
2679 // N.B. Code in reflection should use this entry point.
2680 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2681 Klass* accessing_klass,
2682 Handle class_loader,
2683 Handle protection_domain,
2684 SignatureStream::FailureMode failure_mode,
2685 TRAPS) {
2686 Handle empty;
2687
2688 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2689 "one or the other, or perhaps neither");
2690
2691 Symbol* type = signature;
2692
2693 // What we have here must be a valid field descriptor,
2694 // and all valid field descriptors are supported.
2695 // Produce the same java.lang.Class that reflection reports.
2696 if (type->utf8_length() == 1) {
2697
2698 // It's a primitive. (Void has a primitive mirror too.)
2699 char ch = (char) type->byte_at(0);
2700 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2701 return Handle(THREAD, find_java_mirror_for_type(ch));
2702
2703 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2704
2705 // It's a reference type.
2706 if (accessing_klass != NULL) {
2707 class_loader = Handle(THREAD, accessing_klass->class_loader());
2708 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2709 }
2710 Klass* constant_type_klass;
2711 if (failure_mode == SignatureStream::ReturnNull) {
2712 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2713 CHECK_(empty));
2714 } else {
2715 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2716 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2717 throw_error, CHECK_(empty));
2718 }
2719 if (constant_type_klass == NULL) {
2720 return Handle(); // report failure this way
2721 }
2722 Handle mirror(THREAD, constant_type_klass->java_mirror());
2723
2724 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2725 if (accessing_klass != NULL) {
2726 Klass* sel_klass = constant_type_klass;
2727 bool fold_type_to_class = true;
2728 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2729 fold_type_to_class, CHECK_(empty));
2730 }
2731
2732 return mirror;
2733
2734 }
2735
2736 // Fall through to an error.
2737 assert(false, "unsupported mirror syntax");
2738 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2739 }
2740
2741
2742 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2743 // signature, as interpreted relative to the given class loader.
2744 // Because of class loader constraints, all method handle usage must be
2745 // consistent with this loader.
2746 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2747 Klass* accessing_klass,
2748 TRAPS) {
2749 Handle empty;
2750 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2751 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2752 int index = invoke_method_table()->hash_to_index(hash);
2753 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2754 if (spe != NULL && spe->method_type() != NULL) {
2755 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2756 return Handle(THREAD, spe->method_type());
2757 } else if (!THREAD->can_call_java()) {
2758 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2759 return Handle(); // do not attempt from within compiler, unless it was cached
2760 }
2761
2762 Handle class_loader, protection_domain;
2763 if (accessing_klass != NULL) {
2764 class_loader = Handle(THREAD, accessing_klass->class_loader());
2765 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2766 }
2767 bool can_be_cached = true;
2768 int npts = ArgumentCount(signature).size();
2769 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2770 int arg = 0;
2771 Handle rt; // the return type from the signature
2772 ResourceMark rm(THREAD);
2773 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2774 oop mirror = NULL;
2775 if (can_be_cached) {
2776 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2777 mirror = ss.as_java_mirror(Handle(), Handle(),
2778 SignatureStream::ReturnNull, CHECK_(empty));
2779 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2780 // Fall back to accessing_klass context.
2781 can_be_cached = false;
2782 }
2783 }
2784 if (!can_be_cached) {
2785 // Resolve, throwing a real error if it doesn't work.
2786 mirror = ss.as_java_mirror(class_loader, protection_domain,
2787 SignatureStream::NCDFError, CHECK_(empty));
2788 }
2789 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2790 if (ss.at_return_type())
2791 rt = Handle(THREAD, mirror);
2792 else
2793 pts->obj_at_put(arg++, mirror);
2794
2795 // Check accessibility.
2796 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2797 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2798 mirror = NULL; // safety
2799 // Emulate ConstantPool::verify_constant_pool_resolve.
2800 bool fold_type_to_class = true;
2801 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2802 fold_type_to_class, CHECK_(empty));
2803 }
2804 }
2805 assert(arg == npts, "");
2806
2807 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2808 JavaCallArguments args(Handle(THREAD, rt()));
2809 args.push_oop(pts);
2810 JavaValue result(T_OBJECT);
2811 JavaCalls::call_static(&result,
2812 SystemDictionary::MethodHandleNatives_klass(),
2813 vmSymbols::findMethodHandleType_name(),
2814 vmSymbols::findMethodHandleType_signature(),
2815 &args, CHECK_(empty));
2816 Handle method_type(THREAD, (oop) result.get_jobject());
2817
2818 if (can_be_cached) {
2819 // We can cache this MethodType inside the JVM.
2820 MutexLocker ml(SystemDictionary_lock, THREAD);
2821 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2822 if (spe == NULL)
2823 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2824 if (spe->method_type() == NULL) {
2825 spe->set_method_type(method_type());
2826 }
2827 }
2828
2829 // report back to the caller with the MethodType
2830 return method_type;
2831 }
2832
2833 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2834 Klass* accessing_klass,
2835 TRAPS) {
2836 Handle empty;
2837 ResourceMark rm(THREAD);
2838 SignatureStream ss(signature, /*is_method=*/ false);
2839 if (!ss.is_done()) {
2840 Handle class_loader, protection_domain;
2841 if (accessing_klass != NULL) {
2842 class_loader = Handle(THREAD, accessing_klass->class_loader());
2843 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2844 }
2845 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2846 ss.next();
2847 if (ss.is_done()) {
2848 return Handle(THREAD, mirror);
2849 }
2850 }
2851 return empty;
2852 }
2853
2854 // Ask Java code to find or construct a method handle constant.
2855 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2856 int ref_kind, //e.g., JVM_REF_invokeVirtual
2857 Klass* callee,
2858 Symbol* name,
2859 Symbol* signature,
2860 TRAPS) {
2861 Handle empty;
2862 if (caller == NULL) {
2863 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2864 }
2865 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2866 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2867
2868 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2869 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2870 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2871 java_lang_invoke_MemberName::set_name (mname(), name_str());
2872 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2873 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2874
2875 if (ref_kind == JVM_REF_invokeVirtual &&
2876 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2877 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2878 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2879 // They are public signature polymorphic methods, but require appendix argument
2880 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2881 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2882 } else {
2883 MethodHandles::resolve_MemberName(mname, caller, CHECK_(empty));
2884 }
2885
2886 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2887 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2888
2889 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2890 JavaCallArguments args;
2891 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2892 args.push_int(ref_kind);
2893 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2894 args.push_oop(name_str);
2895 args.push_oop(type);
2896 JavaValue result(T_OBJECT);
2897 JavaCalls::call_static(&result,
2898 SystemDictionary::MethodHandleNatives_klass(),
2899 vmSymbols::linkMethodHandleConstant_name(),
2900 vmSymbols::linkMethodHandleConstant_signature(),
2901 &args, CHECK_(empty));
2902 return Handle(THREAD, (oop) result.get_jobject());
2903 }
2904
2905 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2906 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2907 int condy_index,
2908 Handle bootstrap_specifier,
2909 Symbol* name,
2910 Symbol* type,
2911 TRAPS) {
2912 Handle empty;
2913 Handle bsm, info;
2914 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2915 bsm = bootstrap_specifier;
2916 } else {
2917 assert(bootstrap_specifier->is_objArray(), "");
2918 objArrayOop args = (objArrayOop) bootstrap_specifier();
2919 assert(args->length() == 2, "");
2920 bsm = Handle(THREAD, args->obj_at(0));
2921 info = Handle(THREAD, args->obj_at(1));
2922 }
2923 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2924 "caller must supply a valid BSM");
2925
2926 // This should not happen. JDK code should take care of that.
2927 if (caller == NULL) {
2928 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2929 }
2930
2931 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2932
2933 // Resolve the constant type in the context of the caller class
2934 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2935 CHECK_(empty));
2936
2937 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2938 JavaCallArguments args;
2939 args.push_oop(Handle(THREAD, caller->java_mirror()));
2940 args.push_int(condy_index);
2941 args.push_oop(bsm);
2942 args.push_oop(constant_name);
2943 args.push_oop(type_mirror);
2944 args.push_oop(info);
2945 JavaValue result(T_OBJECT);
2946 JavaCalls::call_static(&result,
2947 SystemDictionary::MethodHandleNatives_klass(),
2948 vmSymbols::linkDynamicConstant_name(),
2949 vmSymbols::linkDynamicConstant_signature(),
2950 &args, CHECK_(empty));
2951
2952 return Handle(THREAD, (oop) result.get_jobject());
2953 }
2954
2955 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2956 // name and signature, as interpreted relative to the given class loader.
2957 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2958 int indy_index,
2959 Handle bootstrap_specifier,
2960 Symbol* name,
2961 Symbol* type,
2962 Handle *appendix_result,
2963 Handle *method_type_result,
2964 TRAPS) {
2965 methodHandle empty;
2966 Handle bsm, info;
2967 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2968 bsm = bootstrap_specifier;
2969 } else {
2970 objArrayOop args = (objArrayOop) bootstrap_specifier();
2971 assert(args->length() == 2, "");
2972 bsm = Handle(THREAD, args->obj_at(0));
2973 info = Handle(THREAD, args->obj_at(1));
2974 }
2975 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2976 "caller must supply a valid BSM");
2977
2978 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2979 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2980
2981 // This should not happen. JDK code should take care of that.
2982 if (caller == NULL || method_type.is_null()) {
2983 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2984 }
2985
2986 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2987 assert(appendix_box->obj_at(0) == NULL, "");
2988
2989 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2990 JavaCallArguments args;
2991 args.push_oop(Handle(THREAD, caller->java_mirror()));
2992 args.push_int(indy_index);
2993 args.push_oop(bsm);
2994 args.push_oop(method_name);
2995 args.push_oop(method_type);
2996 args.push_oop(info);
2997 args.push_oop(appendix_box);
2998 JavaValue result(T_OBJECT);
2999 JavaCalls::call_static(&result,
3000 SystemDictionary::MethodHandleNatives_klass(),
3001 vmSymbols::linkCallSite_name(),
3002 vmSymbols::linkCallSite_signature(),
3003 &args, CHECK_(empty));
3004 Handle mname(THREAD, (oop) result.get_jobject());
3005 (*method_type_result) = method_type;
3006 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
3007 }
3008
3009 // Protection domain cache table handling
3010
3011 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
3012 return _pd_cache_table->get(protection_domain);
3013 }
3014
3015 #if INCLUDE_CDS
3016 void SystemDictionary::reorder_dictionary_for_sharing() {
3017 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
3018 }
3019 #endif
3020
3021 size_t SystemDictionary::count_bytes_for_buckets() {
3022 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
3023 }
3024
3025 size_t SystemDictionary::count_bytes_for_table() {
3026 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
3027 }
3028
3029 void SystemDictionary::copy_buckets(char* top, char* end) {
3030 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
3031 }
3032
3033 void SystemDictionary::copy_table(char* top, char* end) {
3034 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
3035 }
3036
3037 // ----------------------------------------------------------------------------
3038 void SystemDictionary::print_shared(outputStream *st) {
3039 shared_dictionary()->print_on(st);
3040 }
3041
3042 void SystemDictionary::print_on(outputStream *st) {
3043 if (shared_dictionary() != NULL) {
3044 st->print_cr("Shared Dictionary");
3045 shared_dictionary()->print_on(st);
3046 st->cr();
3047 }
3048
3049 GCMutexLocker mu(SystemDictionary_lock);
3050
3051 ClassLoaderDataGraph::print_dictionary(st);
3052
3053 // Placeholders
3054 placeholders()->print_on(st);
3055 st->cr();
3056
3057 // loader constraints - print under SD_lock
3058 constraints()->print_on(st);
3059 st->cr();
3060
3061 _pd_cache_table->print_on(st);
3062 st->cr();
3063 }
3064
3065 void SystemDictionary::verify() {
3066 guarantee(constraints() != NULL,
3067 "Verify of loader constraints failed");
3068 guarantee(placeholders()->number_of_entries() >= 0,
3069 "Verify of placeholders failed");
3070
3071 GCMutexLocker mu(SystemDictionary_lock);
3072
3073 // Verify dictionary
3074 ClassLoaderDataGraph::verify_dictionary();
3075
3076 placeholders()->verify();
3077
3078 // Verify constraint table
3079 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3080 constraints()->verify(placeholders());
3081
3082 _pd_cache_table->verify();
3083 }
3084
3085 void SystemDictionary::dump(outputStream *st, bool verbose) {
3086 assert_locked_or_safepoint(SystemDictionary_lock);
3087 if (verbose) {
3088 print_on(st);
3089 } else {
3090 if (shared_dictionary() != NULL) {
3091 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3092 }
3093 ClassLoaderDataGraph::print_dictionary_statistics(st);
3094 placeholders()->print_table_statistics(st, "Placeholder Table");
3095 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3096 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3097 }
3098 }
3099
3100 // Utility for dumping dictionaries.
3101 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3102 DCmdWithParser(output, heap),
3103 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3104 "BOOLEAN", false, "false") {
3105 _dcmdparser.add_dcmd_option(&_verbose);
3106 }
3107
3108 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3109 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3110 _verbose.value());
3111 VMThread::execute(&dumper);
3112 }
3113
3114 int SystemDictionaryDCmd::num_arguments() {
3115 ResourceMark rm;
3116 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3117 if (dcmd != NULL) {
3118 DCmdMark mark(dcmd);
3119 return dcmd->_dcmdparser.num_arguments();
3120 } else {
3121 return 0;
3122 }
3123 }
3124
3125 class CombineDictionariesClosure : public CLDClosure {
3126 private:
3127 Dictionary* _master_dictionary;
3128 public:
3129 CombineDictionariesClosure(Dictionary* master_dictionary) :
3130 _master_dictionary(master_dictionary) {}
3131 void do_cld(ClassLoaderData* cld) {
3132 ResourceMark rm;
3133 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3134 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3135 Dictionary* curr_dictionary = cld->dictionary();
3136 DictionaryEntry* p = curr_dictionary->bucket(i);
3137 while (p != NULL) {
3138 Symbol* name = p->instance_klass()->name();
3139 unsigned int d_hash = _master_dictionary->compute_hash(name);
3140 int d_index = _master_dictionary->hash_to_index(d_hash);
3141 DictionaryEntry* next = p->next();
3142 if (p->literal()->class_loader_data() != cld) {
3143 // This is an initiating class loader entry; don't use it
3144 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3145 curr_dictionary->free_entry(p);
3146 } else {
3147 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3148 curr_dictionary->unlink_entry(p);
3149 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3150 _master_dictionary->add_entry(d_index, p);
3151 }
3152 p = next;
3153 }
3154 *curr_dictionary->bucket_addr(i) = NULL;
3155 }
3156 }
3157 }
3158 };
3159
3160 // Combining platform and system loader dictionaries into boot loader dictionaries.
3161 // During run time, we only have one shared dictionary.
3162 void SystemDictionary::combine_shared_dictionaries() {
3163 assert(DumpSharedSpaces, "dump time only");
3164 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3165 CombineDictionariesClosure cdc(master_dictionary);
3166 ClassLoaderDataGraph::cld_do(&cdc);
3167
3168 // These tables are no longer valid or necessary. Keeping them around will
3169 // cause SystemDictionary::verify() to fail. Let's empty them.
3170 _placeholders = new PlaceholderTable(_placeholder_table_size);
3171 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3172
3173 NOT_PRODUCT(SystemDictionary::verify());
3174 }
3175
3176 // caller needs ResourceMark
3177 const char* SystemDictionary::loader_name(const oop loader) {
3178 return ((loader) == NULL ? "<bootloader>" :
3179 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3180 }
3181
3182 // caller needs ResourceMark
3183 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3184 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3185 SystemDictionary::loader_name(loader_data->class_loader()));
3186 }