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