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