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