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 "logging/log.hpp"
51 #include "logging/logStream.hpp"
52 #include "memory/filemap.hpp"
53 #include "memory/metaspaceClosure.hpp"
54 #include "memory/oopFactory.hpp"
55 #include "memory/resourceArea.hpp"
56 #include "oops/access.inline.hpp"
57 #include "oops/instanceKlass.hpp"
58 #include "oops/instanceRefKlass.hpp"
59 #include "oops/klass.inline.hpp"
60 #include "oops/method.inline.hpp"
61 #include "oops/methodData.hpp"
62 #include "oops/objArrayKlass.hpp"
63 #include "oops/objArrayOop.inline.hpp"
64 #include "oops/oop.inline.hpp"
65 #include "oops/symbol.hpp"
66 #include "oops/typeArrayKlass.hpp"
67 #include "prims/jvmtiEnvBase.hpp"
68 #include "prims/resolvedMethodTable.hpp"
69 #include "prims/methodHandles.hpp"
70 #include "runtime/arguments.hpp"
71 #include "runtime/arguments_ext.hpp"
72 #include "runtime/biasedLocking.hpp"
73 #include "runtime/fieldType.hpp"
74 #include "runtime/handles.inline.hpp"
75 #include "runtime/java.hpp"
76 #include "runtime/javaCalls.hpp"
77 #include "runtime/mutexLocker.hpp"
78 #include "runtime/orderAccess.inline.hpp"
79 #include "runtime/sharedRuntime.hpp"
80 #include "runtime/signature.hpp"
81 #include "services/classLoadingService.hpp"
82 #include "services/diagnosticCommand.hpp"
83 #include "services/threadService.hpp"
84 #include "trace/tracing.hpp"
85 #include "utilities/macros.hpp"
86 #if INCLUDE_CDS
87 #include "classfile/sharedClassUtil.hpp"
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JVMCI
91 #include "jvmci/jvmciRuntime.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 Dictionary* SystemDictionary::_shared_dictionary = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 int SystemDictionary::_number_of_modifications = 0;
102 oop SystemDictionary::_system_loader_lock_obj = NULL;
103
104 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
105 = { NULL /*, NULL...*/ };
106
107 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
108
109 oop SystemDictionary::_java_system_loader = NULL;
110 oop SystemDictionary::_java_platform_loader = NULL;
111
112 bool SystemDictionary::_has_checkPackageAccess = false;
113
114 // lazily initialized klass variables
115 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
116
117 // Default ProtectionDomainCacheSize value
118
119 const int defaultProtectionDomainCacheSize = 1009;
120
121 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
122
123
124 // ----------------------------------------------------------------------------
125 // Java-level SystemLoader and PlatformLoader
126
127 oop SystemDictionary::java_system_loader() {
128 return _java_system_loader;
129 }
130
131 oop SystemDictionary::java_platform_loader() {
132 return _java_platform_loader;
133 }
134
135 void SystemDictionary::compute_java_loaders(TRAPS) {
136 JavaValue result(T_OBJECT);
137 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
138 JavaCalls::call_static(&result,
139 class_loader_klass,
140 vmSymbols::getSystemClassLoader_name(),
141 vmSymbols::void_classloader_signature(),
142 CHECK);
143
144 _java_system_loader = (oop)result.get_jobject();
145
146 JavaCalls::call_static(&result,
147 class_loader_klass,
148 vmSymbols::getPlatformClassLoader_name(),
149 vmSymbols::void_classloader_signature(),
150 CHECK);
151
152 _java_platform_loader = (oop)result.get_jobject();
153
154 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
155 }
156
157 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
158 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
159 return ClassLoaderDataGraph::find_or_create(class_loader);
160 }
161
162 // ----------------------------------------------------------------------------
163 // Parallel class loading check
164
165 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
166 if (class_loader.is_null()) return true;
167 if (AlwaysLockClassLoader) return false;
168 return java_lang_ClassLoader::parallelCapable(class_loader());
169 }
170 // ----------------------------------------------------------------------------
171 // ParallelDefineClass flag does not apply to bootclass loader
172 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
173 if (class_loader.is_null()) return false;
174 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
175 return true;
176 }
177 return false;
178 }
179
180 // Returns true if the passed class loader is the builtin application class loader
181 // or a custom system class loader. A customer system class loader can be
182 // specified via -Djava.system.class.loader.
183 bool SystemDictionary::is_system_class_loader(oop class_loader) {
184 if (class_loader == NULL) {
185 return false;
186 }
187 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
188 oopDesc::equals(class_loader, _java_system_loader));
189 }
190
191 // Returns true if the passed class loader is the platform class loader.
192 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
193 if (class_loader == NULL) {
194 return false;
195 }
196 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
197 }
198
199 // ----------------------------------------------------------------------------
200 // Resolving of classes
201
202 // Forwards to resolve_or_null
203
204 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
205 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
206 if (HAS_PENDING_EXCEPTION || klass == NULL) {
207 // can return a null klass
208 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
209 }
210 return klass;
211 }
212
213 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
214 bool throw_error,
215 Klass* klass, TRAPS) {
216 if (HAS_PENDING_EXCEPTION) {
217 // If we have a pending exception we forward it to the caller, unless throw_error is true,
218 // in which case we have to check whether the pending exception is a ClassNotFoundException,
219 // and if so convert it to a NoClassDefFoundError
220 // And chain the original ClassNotFoundException
221 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
222 ResourceMark rm(THREAD);
223 assert(klass == NULL, "Should not have result with exception pending");
224 Handle e(THREAD, PENDING_EXCEPTION);
225 CLEAR_PENDING_EXCEPTION;
226 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
227 } else {
228 return NULL;
229 }
230 }
231 // Class not found, throw appropriate error or exception depending on value of throw_error
232 if (klass == NULL) {
233 ResourceMark rm(THREAD);
234 if (throw_error) {
235 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
236 } else {
237 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
238 }
239 }
240 return klass;
241 }
242
243
244 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
245 bool throw_error, TRAPS)
246 {
247 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
248 }
249
250
251 // Forwards to resolve_instance_class_or_null
252
253 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
254 assert(THREAD->can_call_java(),
255 "can not load classes with compiler thread: class=%s, classloader=%s",
256 class_name->as_C_string(),
257 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
258 if (FieldType::is_array(class_name)) {
259 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
260 } else if (FieldType::is_obj(class_name)) {
261 ResourceMark rm(THREAD);
262 // Ignore wrapping L and ;.
263 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
264 class_name->utf8_length() - 2, CHECK_NULL);
265 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
266 } else {
267 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
268 }
269 }
270
271 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
272 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
273 }
274
275 // Forwards to resolve_instance_class_or_null
276
277 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
278 Handle class_loader,
279 Handle protection_domain,
280 TRAPS) {
281 assert(FieldType::is_array(class_name), "must be array");
282 Klass* k = NULL;
283 FieldArrayInfo fd;
284 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
285 // of this call
286 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
287 if (t == T_OBJECT) {
288 // naked oop "k" is OK here -- we assign back into it
289 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
290 class_loader,
291 protection_domain,
292 CHECK_NULL);
293 if (k != NULL) {
294 k = k->array_klass(fd.dimension(), CHECK_NULL);
295 }
296 } else {
297 k = Universe::typeArrayKlassObj(t);
298 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
299 }
300 return k;
301 }
302
303
304 // Must be called for any super-class or super-interface resolution
305 // during class definition to allow class circularity checking
306 // super-interface callers:
307 // parse_interfaces - for defineClass & jvmtiRedefineClasses
308 // super-class callers:
309 // ClassFileParser - for defineClass & jvmtiRedefineClasses
310 // load_shared_class - while loading a class from shared archive
311 // resolve_instance_class_or_null:
312 // via: handle_parallel_super_load
313 // when resolving a class that has an existing placeholder with
314 // a saved superclass [i.e. a defineClass is currently in progress]
315 // if another thread is trying to resolve the class, it must do
316 // super-class checks on its own thread to catch class circularity
317 // This last call is critical in class circularity checking for cases
318 // where classloading is delegated to different threads and the
319 // classloader lock is released.
320 // Take the case: Base->Super->Base
321 // 1. If thread T1 tries to do a defineClass of class Base
322 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
323 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
324 // so it tries to load Super
325 // 3. If we load the class internally, or user classloader uses same thread
326 // loadClassFromxxx or defineClass via parseClassFile Super ...
327 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
328 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
329 // 3.4 calls resolve_super_or_fail Base
330 // 3.5 finds T1,Base -> throws class circularity
331 //OR 4. If T2 tries to resolve Super via defineClass Super ...
332 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
333 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
334 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
335 // 4.4 finds T2, Super -> throws class circularity
336 // Must be called, even if superclass is null, since this is
337 // where the placeholder entry is created which claims this
338 // thread is loading this class/classloader.
339 // Be careful when modifying this code: once you have run
340 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
341 // you need to find_and_remove it before returning.
342 // So be careful to not exit with a CHECK_ macro betweeen these calls.
343 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
344 Symbol* class_name,
345 Handle class_loader,
346 Handle protection_domain,
347 bool is_superclass,
348 TRAPS) {
349 #if INCLUDE_CDS
350 if (DumpSharedSpaces) {
351 // Special processing for CDS dump time.
352 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
353 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
354 if (k) {
355 return k;
356 }
357 }
358 #endif // INCLUDE_CDS
359
360 // Double-check, if child class is already loaded, just return super-class,interface
361 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
362 // dictionary.
363 // Make sure there's a placeholder for the *child* before resolving.
364 // Used as a claim that this thread is currently loading superclass/classloader
365 // Used here for ClassCircularity checks and also for heap verification
366 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
367 // Must check ClassCircularity before checking if super class is already loaded.
368 //
369 // We might not already have a placeholder if this child_name was
370 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
371 // the name of the class might not be known until the stream is actually
372 // parsed.
373 // Bugs 4643874, 4715493
374
375 ClassLoaderData* loader_data = class_loader_data(class_loader);
376 Dictionary* dictionary = loader_data->dictionary();
377 unsigned int d_hash = dictionary->compute_hash(child_name);
378 unsigned int p_hash = placeholders()->compute_hash(child_name);
379 int p_index = placeholders()->hash_to_index(p_hash);
380 // can't throw error holding a lock
381 bool child_already_loaded = false;
382 bool throw_circularity_error = false;
383 {
384 MutexLocker mu(SystemDictionary_lock, THREAD);
385 Klass* childk = find_class(d_hash, child_name, dictionary);
386 Klass* quicksuperk;
387 // to support // loading: if child done loading, just return superclass
388 // if class_name, & class_loader don't match:
389 // if initial define, SD update will give LinkageError
390 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
391 // so we don't throw an exception here.
392 // see: nsk redefclass014 & java.lang.instrument Instrument032
393 if ((childk != NULL ) && (is_superclass) &&
394 ((quicksuperk = childk->super()) != NULL) &&
395
396 ((quicksuperk->name() == class_name) &&
397 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
398 return quicksuperk;
399 } else {
400 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
401 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
402 throw_circularity_error = true;
403 }
404 }
405 if (!throw_circularity_error) {
406 // Be careful not to exit resolve_super
407 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
408 }
409 }
410 if (throw_circularity_error) {
411 ResourceMark rm(THREAD);
412 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
413 }
414
415 // java.lang.Object should have been found above
416 assert(class_name != NULL, "null super class for resolving");
417 // Resolve the super class or interface, check results on return
418 Klass* superk = SystemDictionary::resolve_or_null(class_name,
419 class_loader,
420 protection_domain,
421 THREAD);
422
423 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
424 // It is no longer necessary to keep the placeholder table alive until update_dictionary
425 // or error. GC used to walk the placeholder table as strong roots.
426 // The instanceKlass is kept alive because the class loader is on the stack,
427 // which keeps the loader_data alive, as well as all instanceKlasses in
428 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
429 {
430 MutexLocker mu(SystemDictionary_lock, THREAD);
431 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
432 SystemDictionary_lock->notify_all();
433 }
434 if (HAS_PENDING_EXCEPTION || superk == NULL) {
435 // can null superk
436 superk = handle_resolution_exception(class_name, true, superk, THREAD);
437 }
438
439 return superk;
440 }
441
442 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
443 Handle class_loader,
444 Handle protection_domain,
445 TRAPS) {
446 if(!has_checkPackageAccess()) return;
447
448 // Now we have to call back to java to check if the initating class has access
449 JavaValue result(T_VOID);
450 LogTarget(Debug, protectiondomain) lt;
451 if (lt.is_enabled()) {
452 ResourceMark rm;
453 // Print out trace information
454 LogStream ls(lt);
455 ls.print_cr("Checking package access");
456 ls.print("class loader: "); class_loader()->print_value_on(&ls);
457 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
458 ls.print(" loading: "); klass->print_value_on(&ls);
459 ls.cr();
460 }
461
462 // This handle and the class_loader handle passed in keeps this class from
463 // being unloaded through several GC points.
464 // The class_loader handle passed in is the initiating loader.
465 Handle mirror(THREAD, klass->java_mirror());
466
467 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
468 JavaCalls::call_special(&result,
469 class_loader,
470 system_loader,
471 vmSymbols::checkPackageAccess_name(),
472 vmSymbols::class_protectiondomain_signature(),
473 mirror,
474 protection_domain,
475 THREAD);
476
477 if (HAS_PENDING_EXCEPTION) {
478 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
479 } else {
480 log_debug(protectiondomain)("granted");
481 }
482
483 if (HAS_PENDING_EXCEPTION) return;
484
485 // If no exception has been thrown, we have validated the protection domain
486 // Insert the protection domain of the initiating class into the set.
487 {
488 ClassLoaderData* loader_data = class_loader_data(class_loader);
489 Dictionary* dictionary = loader_data->dictionary();
490
491 Symbol* kn = klass->name();
492 unsigned int d_hash = dictionary->compute_hash(kn);
493
494 MutexLocker mu(SystemDictionary_lock, THREAD);
495 int d_index = dictionary->hash_to_index(d_hash);
496 dictionary->add_protection_domain(d_index, d_hash, klass,
497 protection_domain, THREAD);
498 }
499 }
500
501 // We only get here if this thread finds that another thread
502 // has already claimed the placeholder token for the current operation,
503 // but that other thread either never owned or gave up the
504 // object lock
505 // Waits on SystemDictionary_lock to indicate placeholder table updated
506 // On return, caller must recheck placeholder table state
507 //
508 // We only get here if
509 // 1) custom classLoader, i.e. not bootstrap classloader
510 // 2) custom classLoader has broken the class loader objectLock
511 // so another thread got here in parallel
512 //
513 // lockObject must be held.
514 // Complicated dance due to lock ordering:
515 // Must first release the classloader object lock to
516 // allow initial definer to complete the class definition
517 // and to avoid deadlock
518 // Reclaim classloader lock object with same original recursion count
519 // Must release SystemDictionary_lock after notify, since
520 // class loader lock must be claimed before SystemDictionary_lock
521 // to prevent deadlocks
522 //
523 // The notify allows applications that did an untimed wait() on
524 // the classloader object lock to not hang.
525 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
526 assert_lock_strong(SystemDictionary_lock);
527
528 bool calledholdinglock
529 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
530 assert(calledholdinglock,"must hold lock for notify");
531 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
532 ObjectSynchronizer::notifyall(lockObject, THREAD);
533 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
534 SystemDictionary_lock->wait();
535 SystemDictionary_lock->unlock();
536 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
537 SystemDictionary_lock->lock();
538 }
539
540 // If the class in is in the placeholder table, class loading is in progress
541 // For cases where the application changes threads to load classes, it
542 // is critical to ClassCircularity detection that we try loading
543 // the superclass on the same thread internally, so we do parallel
544 // super class loading here.
545 // This also is critical in cases where the original thread gets stalled
546 // even in non-circularity situations.
547 // Note: must call resolve_super_or_fail even if null super -
548 // to force placeholder entry creation for this class for circularity detection
549 // Caller must check for pending exception
550 // Returns non-null Klass* if other thread has completed load
551 // and we are done,
552 // If return null Klass* and no pending exception, the caller must load the class
553 InstanceKlass* SystemDictionary::handle_parallel_super_load(
554 Symbol* name, Symbol* superclassname, Handle class_loader,
555 Handle protection_domain, Handle lockObject, TRAPS) {
556
557 ClassLoaderData* loader_data = class_loader_data(class_loader);
558 Dictionary* dictionary = loader_data->dictionary();
559 unsigned int d_hash = dictionary->compute_hash(name);
560 unsigned int p_hash = placeholders()->compute_hash(name);
561 int p_index = placeholders()->hash_to_index(p_hash);
562
563 // superk is not used, resolve_super called for circularity check only
564 // This code is reached in two situations. One if this thread
565 // is loading the same class twice (e.g. ClassCircularity, or
566 // java.lang.instrument).
567 // The second is if another thread started the resolve_super first
568 // and has not yet finished.
569 // In both cases the original caller will clean up the placeholder
570 // entry on error.
571 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
572 superclassname,
573 class_loader,
574 protection_domain,
575 true,
576 CHECK_NULL);
577
578 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
579 // Serial class loaders and bootstrap classloader do wait for superclass loads
580 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
581 MutexLocker mu(SystemDictionary_lock, THREAD);
582 // Check if classloading completed while we were loading superclass or waiting
583 return find_class(d_hash, name, dictionary);
584 }
585
586 // must loop to both handle other placeholder updates
587 // and spurious notifications
588 bool super_load_in_progress = true;
589 PlaceholderEntry* placeholder;
590 while (super_load_in_progress) {
591 MutexLocker mu(SystemDictionary_lock, THREAD);
592 // Check if classloading completed while we were loading superclass or waiting
593 InstanceKlass* check = find_class(d_hash, name, dictionary);
594 if (check != NULL) {
595 // Klass is already loaded, so just return it
596 return check;
597 } else {
598 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
599 if (placeholder && placeholder->super_load_in_progress() ){
600 // We only get here if the application has released the
601 // classloader lock when another thread was in the middle of loading a
602 // superclass/superinterface for this class, and now
603 // this thread is also trying to load this class.
604 // To minimize surprises, the first thread that started to
605 // load a class should be the one to complete the loading
606 // with the classfile it initially expected.
607 // This logic has the current thread wait once it has done
608 // all the superclass/superinterface loading it can, until
609 // the original thread completes the class loading or fails
610 // If it completes we will use the resulting InstanceKlass
611 // which we will find below in the systemDictionary.
612 // We also get here for parallel bootstrap classloader
613 if (class_loader.is_null()) {
614 SystemDictionary_lock->wait();
615 } else {
616 double_lock_wait(lockObject, THREAD);
617 }
618 } else {
619 // If not in SD and not in PH, other thread's load must have failed
620 super_load_in_progress = false;
621 }
622 }
623 }
624 return NULL;
625 }
626
627 static void post_class_load_event(EventClassLoad* event,
628 const InstanceKlass* k,
629 const ClassLoaderData* init_cld) {
630 #if INCLUDE_TRACE
631 assert(event != NULL, "invariant");
632 assert(k != NULL, "invariant");
633 if (event->should_commit()) {
634 event->set_loadedClass(k);
635 event->set_definingClassLoader(k->class_loader_data());
636 event->set_initiatingClassLoader(init_cld);
637 event->commit();
638 }
639 #endif // INCLUDE_TRACE
640 }
641
642 static void class_define_event(InstanceKlass* k,
643 const ClassLoaderData* def_cld) {
644 #if INCLUDE_TRACE
645 EventClassDefine event;
646 if (event.should_commit()) {
647 event.set_definedClass(k);
648 event.set_definingClassLoader(def_cld);
649 event.commit();
650 }
651 #endif // INCLUDE_TRACE
652 }
653
654 // Be careful when modifying this code: once you have run
655 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
656 // you need to find_and_remove it before returning.
657 // So be careful to not exit with a CHECK_ macro betweeen these calls.
658 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
659 Handle class_loader,
660 Handle protection_domain,
661 TRAPS) {
662 assert(name != NULL && !FieldType::is_array(name) &&
663 !FieldType::is_obj(name), "invalid class name");
664
665 EventClassLoad class_load_start_event;
666
667 HandleMark hm(THREAD);
668
669 // Fix for 4474172; see evaluation for more details
670 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
671 ClassLoaderData* loader_data = register_loader(class_loader);
672 Dictionary* dictionary = loader_data->dictionary();
673 unsigned int d_hash = dictionary->compute_hash(name);
674
675 // Do lookup to see if class already exist and the protection domain
676 // has the right access
677 // This call uses find which checks protection domain already matches
678 // All subsequent calls use find_class, and set has_loaded_class so that
679 // before we return a result we call out to java to check for valid protection domain
680 // to allow returning the Klass* and add it to the pd_set if it is valid
681 {
682 Klass* probe = dictionary->find(d_hash, name, protection_domain);
683 if (probe != NULL) return probe;
684 }
685
686 // Non-bootstrap class loaders will call out to class loader and
687 // define via jvm/jni_DefineClass which will acquire the
688 // class loader object lock to protect against multiple threads
689 // defining the class in parallel by accident.
690 // This lock must be acquired here so the waiter will find
691 // any successful result in the SystemDictionary and not attempt
692 // the define.
693 // ParallelCapable Classloaders and the bootstrap classloader
694 // do not acquire lock here.
695 bool DoObjectLock = true;
696 if (is_parallelCapable(class_loader)) {
697 DoObjectLock = false;
698 }
699
700 unsigned int p_hash = placeholders()->compute_hash(name);
701 int p_index = placeholders()->hash_to_index(p_hash);
702
703 // Class is not in SystemDictionary so we have to do loading.
704 // Make sure we are synchronized on the class loader before we proceed
705 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
706 check_loader_lock_contention(lockObject, THREAD);
707 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
708
709 // Check again (after locking) if class already exist in SystemDictionary
710 bool class_has_been_loaded = false;
711 bool super_load_in_progress = false;
712 bool havesupername = false;
713 InstanceKlass* k = NULL;
714 PlaceholderEntry* placeholder;
715 Symbol* superclassname = NULL;
716
717 {
718 MutexLocker mu(SystemDictionary_lock, THREAD);
719 InstanceKlass* check = find_class(d_hash, name, dictionary);
720 if (check != NULL) {
721 // Klass is already loaded, so just return it
722 class_has_been_loaded = true;
723 k = check;
724 } else {
725 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
726 if (placeholder && placeholder->super_load_in_progress()) {
727 super_load_in_progress = true;
728 if (placeholder->havesupername() == true) {
729 superclassname = placeholder->supername();
730 havesupername = true;
731 }
732 }
733 }
734 }
735
736 // If the class is in the placeholder table, class loading is in progress
737 if (super_load_in_progress && havesupername==true) {
738 k = handle_parallel_super_load(name,
739 superclassname,
740 class_loader,
741 protection_domain,
742 lockObject, THREAD);
743 if (HAS_PENDING_EXCEPTION) {
744 return NULL;
745 }
746 if (k != NULL) {
747 class_has_been_loaded = true;
748 }
749 }
750
751 bool throw_circularity_error = false;
752 if (!class_has_been_loaded) {
753 bool load_instance_added = false;
754
755 // add placeholder entry to record loading instance class
756 // Five cases:
757 // All cases need to prevent modifying bootclasssearchpath
758 // in parallel with a classload of same classname
759 // Redefineclasses uses existence of the placeholder for the duration
760 // of the class load to prevent concurrent redefinition of not completely
761 // defined classes.
762 // case 1. traditional classloaders that rely on the classloader object lock
763 // - no other need for LOAD_INSTANCE
764 // case 2. traditional classloaders that break the classloader object lock
765 // as a deadlock workaround. Detection of this case requires that
766 // this check is done while holding the classloader object lock,
767 // and that lock is still held when calling classloader's loadClass.
768 // For these classloaders, we ensure that the first requestor
769 // completes the load and other requestors wait for completion.
770 // case 3. Bootstrap classloader - don't own objectLocker
771 // This classloader supports parallelism at the classloader level,
772 // but only allows a single load of a class/classloader pair.
773 // No performance benefit and no deadlock issues.
774 // case 4. parallelCapable user level classloaders - without objectLocker
775 // Allow parallel classloading of a class/classloader pair
776
777 {
778 MutexLocker mu(SystemDictionary_lock, THREAD);
779 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
780 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
781 if (oldprobe) {
782 // only need check_seen_thread once, not on each loop
783 // 6341374 java/lang/Instrument with -Xcomp
784 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
785 throw_circularity_error = true;
786 } else {
787 // case 1: traditional: should never see load_in_progress.
788 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
789
790 // case 3: bootstrap classloader: prevent futile classloading,
791 // wait on first requestor
792 if (class_loader.is_null()) {
793 SystemDictionary_lock->wait();
794 } else {
795 // case 2: traditional with broken classloader lock. wait on first
796 // requestor.
797 double_lock_wait(lockObject, THREAD);
798 }
799 // Check if classloading completed while we were waiting
800 InstanceKlass* check = find_class(d_hash, name, dictionary);
801 if (check != NULL) {
802 // Klass is already loaded, so just return it
803 k = check;
804 class_has_been_loaded = true;
805 }
806 // check if other thread failed to load and cleaned up
807 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
808 }
809 }
810 }
811 }
812 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
813 // case 4: parallelCapable: allow competing threads to try
814 // LOAD_INSTANCE in parallel
815
816 if (!throw_circularity_error && !class_has_been_loaded) {
817 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
818 load_instance_added = true;
819 // For class loaders that do not acquire the classloader object lock,
820 // if they did not catch another thread holding LOAD_INSTANCE,
821 // need a check analogous to the acquire ObjectLocker/find_class
822 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
823 // one final check if the load has already completed
824 // class loaders holding the ObjectLock shouldn't find the class here
825 InstanceKlass* check = find_class(d_hash, name, dictionary);
826 if (check != NULL) {
827 // Klass is already loaded, so return it after checking/adding protection domain
828 k = check;
829 class_has_been_loaded = true;
830 }
831 }
832 }
833
834 // must throw error outside of owning lock
835 if (throw_circularity_error) {
836 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
837 ResourceMark rm(THREAD);
838 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
839 }
840
841 if (!class_has_been_loaded) {
842
843 // Do actual loading
844 k = load_instance_class(name, class_loader, THREAD);
845
846 // If everything was OK (no exceptions, no null return value), and
847 // class_loader is NOT the defining loader, do a little more bookkeeping.
848 if (!HAS_PENDING_EXCEPTION && k != NULL &&
849 !oopDesc::equals(k->class_loader(), class_loader())) {
850
851 check_constraints(d_hash, k, class_loader, false, THREAD);
852
853 // Need to check for a PENDING_EXCEPTION again; check_constraints
854 // can throw and doesn't use the CHECK macro.
855 if (!HAS_PENDING_EXCEPTION) {
856 { // Grabbing the Compile_lock prevents systemDictionary updates
857 // during compilations.
858 MutexLocker mu(Compile_lock, THREAD);
859 update_dictionary(d_hash, p_index, p_hash,
860 k, class_loader, THREAD);
861 }
862
863 if (JvmtiExport::should_post_class_load()) {
864 Thread *thread = THREAD;
865 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
866 JvmtiExport::post_class_load((JavaThread *) thread, k);
867 }
868 }
869 }
870 } // load_instance_class
871
872 if (load_instance_added == true) {
873 // clean up placeholder entries for LOAD_INSTANCE success or error
874 // This brackets the SystemDictionary updates for both defining
875 // and initiating loaders
876 MutexLocker mu(SystemDictionary_lock, THREAD);
877 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
878 SystemDictionary_lock->notify_all();
879 }
880 }
881
882 if (HAS_PENDING_EXCEPTION || k == NULL) {
883 return NULL;
884 }
885
886 post_class_load_event(&class_load_start_event, k, loader_data);
887
888 #ifdef ASSERT
889 {
890 ClassLoaderData* loader_data = k->class_loader_data();
891 MutexLocker mu(SystemDictionary_lock, THREAD);
892 Klass* kk = find_class(name, loader_data);
893 assert(kk == k, "should be present in dictionary");
894 }
895 #endif
896
897 // return if the protection domain in NULL
898 if (protection_domain() == NULL) return k;
899
900 // Check the protection domain has the right access
901 if (dictionary->is_valid_protection_domain(d_hash, name,
902 protection_domain)) {
903 return k;
904 }
905
906 // Verify protection domain. If it fails an exception is thrown
907 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
908
909 return k;
910 }
911
912
913 // This routine does not lock the system dictionary.
914 //
915 // Since readers don't hold a lock, we must make sure that system
916 // dictionary entries are only removed at a safepoint (when only one
917 // thread is running), and are added to in a safe way (all links must
918 // be updated in an MT-safe manner).
919 //
920 // Callers should be aware that an entry could be added just after
921 // _dictionary->bucket(index) is read here, so the caller will not see
922 // the new entry.
923
924 Klass* SystemDictionary::find(Symbol* class_name,
925 Handle class_loader,
926 Handle protection_domain,
927 TRAPS) {
928
929 // The result of this call should be consistent with the result
930 // of the call to resolve_instance_class_or_null().
931 // See evaluation 6790209 and 4474172 for more details.
932 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
933 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
934
935 if (loader_data == NULL) {
936 // If the ClassLoaderData has not been setup,
937 // then the class loader has no entries in the dictionary.
938 return NULL;
939 }
940
941 Dictionary* dictionary = loader_data->dictionary();
942 unsigned int d_hash = dictionary->compute_hash(class_name);
943 return dictionary->find(d_hash, class_name,
944 protection_domain);
945 }
946
947
948 // Look for a loaded instance or array klass by name. Do not do any loading.
949 // return NULL in case of error.
950 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
951 Handle class_loader,
952 Handle protection_domain,
953 TRAPS) {
954 Klass* k = NULL;
955 assert(class_name != NULL, "class name must be non NULL");
956
957 if (FieldType::is_array(class_name)) {
958 // The name refers to an array. Parse the name.
959 // dimension and object_key in FieldArrayInfo are assigned as a
960 // side-effect of this call
961 FieldArrayInfo fd;
962 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
963 if (t != T_OBJECT) {
964 k = Universe::typeArrayKlassObj(t);
965 } else {
966 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
967 }
968 if (k != NULL) {
969 k = k->array_klass_or_null(fd.dimension());
970 }
971 } else {
972 k = find(class_name, class_loader, protection_domain, THREAD);
973 }
974 return k;
975 }
976
977 // Note: this method is much like resolve_from_stream, but
978 // does not publish the classes via the SystemDictionary.
979 // Handles unsafe_DefineAnonymousClass and redefineclasses
980 // RedefinedClasses do not add to the class hierarchy
981 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
982 Handle class_loader,
983 Handle protection_domain,
984 ClassFileStream* st,
985 const InstanceKlass* host_klass,
986 GrowableArray<Handle>* cp_patches,
987 TRAPS) {
988
989 EventClassLoad class_load_start_event;
990
991 ClassLoaderData* loader_data;
992 if (host_klass != NULL) {
993 // Create a new CLD for anonymous class, that uses the same class loader
994 // as the host_klass
995 guarantee(oopDesc::equals(host_klass->class_loader(), class_loader()), "should be the same");
996 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader);
997 } else {
998 loader_data = ClassLoaderData::class_loader_data(class_loader());
999 }
1000
1001 assert(st != NULL, "invariant");
1002 assert(st->need_verify(), "invariant");
1003
1004 // Parse stream and create a klass.
1005 // Note that we do this even though this klass might
1006 // already be present in the SystemDictionary, otherwise we would not
1007 // throw potential ClassFormatErrors.
1008
1009 InstanceKlass* k = KlassFactory::create_from_stream(st,
1010 class_name,
1011 loader_data,
1012 protection_domain,
1013 host_klass,
1014 cp_patches,
1015 CHECK_NULL);
1016
1017 if (host_klass != NULL && k != NULL) {
1018 // Anonymous classes must update ClassLoaderData holder (was host_klass loader)
1019 // so that they can be unloaded when the mirror is no longer referenced.
1020 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1021
1022 {
1023 MutexLocker mu_r(Compile_lock, THREAD);
1024
1025 // Add to class hierarchy, initialize vtables, and do possible
1026 // deoptimizations.
1027 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1028
1029 // But, do not add to dictionary.
1030
1031 // compiled code dependencies need to be validated anyway
1032 notice_modification();
1033 }
1034
1035 // Rewrite and patch constant pool here.
1036 k->link_class(CHECK_NULL);
1037 if (cp_patches != NULL) {
1038 k->constants()->patch_resolved_references(cp_patches);
1039 }
1040
1041 // If it's anonymous, initialize it now, since nobody else will.
1042 k->eager_initialize(CHECK_NULL);
1043
1044 // notify jvmti
1045 if (JvmtiExport::should_post_class_load()) {
1046 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1047 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1048 }
1049
1050 post_class_load_event(&class_load_start_event, k, loader_data);
1051 }
1052 assert(host_klass != NULL || NULL == cp_patches,
1053 "cp_patches only found with host_klass");
1054
1055 return k;
1056 }
1057
1058 // Add a klass to the system from a stream (called by jni_DefineClass and
1059 // JVM_DefineClass).
1060 // Note: class_name can be NULL. In that case we do not know the name of
1061 // the class until we have parsed the stream.
1062
1063 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1064 Handle class_loader,
1065 Handle protection_domain,
1066 ClassFileStream* st,
1067 TRAPS) {
1068
1069 HandleMark hm(THREAD);
1070
1071 // Classloaders that support parallelism, e.g. bootstrap classloader,
1072 // do not acquire lock here
1073 bool DoObjectLock = true;
1074 if (is_parallelCapable(class_loader)) {
1075 DoObjectLock = false;
1076 }
1077
1078 ClassLoaderData* loader_data = register_loader(class_loader);
1079
1080 // Make sure we are synchronized on the class loader before we proceed
1081 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1082 check_loader_lock_contention(lockObject, THREAD);
1083 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1084
1085 assert(st != NULL, "invariant");
1086
1087 // Parse the stream and create a klass.
1088 // Note that we do this even though this klass might
1089 // already be present in the SystemDictionary, otherwise we would not
1090 // throw potential ClassFormatErrors.
1091 InstanceKlass* k = NULL;
1092
1093 #if INCLUDE_CDS
1094 if (!DumpSharedSpaces) {
1095 k = SystemDictionaryShared::lookup_from_stream(class_name,
1096 class_loader,
1097 protection_domain,
1098 st,
1099 CHECK_NULL);
1100 }
1101 #endif
1102
1103 if (k == NULL) {
1104 if (st->buffer() == NULL) {
1105 return NULL;
1106 }
1107 k = KlassFactory::create_from_stream(st,
1108 class_name,
1109 loader_data,
1110 protection_domain,
1111 NULL, // host_klass
1112 NULL, // cp_patches
1113 CHECK_NULL);
1114 }
1115
1116 assert(k != NULL, "no klass created");
1117 Symbol* h_name = k->name();
1118 assert(class_name == NULL || class_name == h_name, "name mismatch");
1119
1120 // Add class just loaded
1121 // If a class loader supports parallel classloading handle parallel define requests
1122 // find_or_define_instance_class may return a different InstanceKlass
1123 if (is_parallelCapable(class_loader)) {
1124 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1125 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1126 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1127 assert(defined_k != NULL, "Should have a klass if there's no exception");
1128 loader_data->add_to_deallocate_list(k);
1129 k = defined_k;
1130 }
1131 } else {
1132 define_instance_class(k, THREAD);
1133 }
1134
1135 // If defining the class throws an exception register 'k' for cleanup.
1136 if (HAS_PENDING_EXCEPTION) {
1137 assert(k != NULL, "Must have an instance klass here!");
1138 loader_data->add_to_deallocate_list(k);
1139 return NULL;
1140 }
1141
1142 // Make sure we have an entry in the SystemDictionary on success
1143 debug_only( {
1144 MutexLocker mu(SystemDictionary_lock, THREAD);
1145
1146 Klass* check = find_class(h_name, k->class_loader_data());
1147 assert(check == k, "should be present in the dictionary");
1148 } );
1149
1150 return k;
1151 }
1152
1153 #if INCLUDE_CDS
1154 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1155 int number_of_entries) {
1156 assert(length == _shared_dictionary_size * sizeof(HashtableBucket<mtClass>),
1157 "bad shared dictionary size.");
1158 _shared_dictionary = new Dictionary(ClassLoaderData::the_null_class_loader_data(),
1159 _shared_dictionary_size, t, number_of_entries);
1160 }
1161
1162
1163 // If there is a shared dictionary, then find the entry for the
1164 // given shared system class, if any.
1165
1166 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1167 if (shared_dictionary() != NULL) {
1168 unsigned int d_hash = shared_dictionary()->compute_hash(class_name);
1169 int d_index = shared_dictionary()->hash_to_index(d_hash);
1170
1171 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1172 } else {
1173 return NULL;
1174 }
1175 }
1176
1177
1178 // Load a class from the shared spaces (found through the shared system
1179 // dictionary). Force the superclass and all interfaces to be loaded.
1180 // Update the class definition to include sibling classes and no
1181 // subclasses (yet). [Classes in the shared space are not part of the
1182 // object hierarchy until loaded.]
1183
1184 InstanceKlass* SystemDictionary::load_shared_class(
1185 Symbol* class_name, Handle class_loader, TRAPS) {
1186 InstanceKlass* ik = find_shared_class(class_name);
1187 // Make sure we only return the boot class for the NULL classloader.
1188 if (ik != NULL &&
1189 ik->is_shared_boot_class() && class_loader.is_null()) {
1190 Handle protection_domain;
1191 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1192 }
1193 return NULL;
1194 }
1195
1196 // Check if a shared class can be loaded by the specific classloader:
1197 //
1198 // NULL classloader:
1199 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1200 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1201 // be defined in an unnamed module.
1202 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1203 InstanceKlass* ik,
1204 Handle class_loader, TRAPS) {
1205 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1206 "Cannot use sharing if java.base is patched");
1207 ResourceMark rm;
1208 int path_index = ik->shared_classpath_index();
1209 ClassLoaderData* loader_data = class_loader_data(class_loader);
1210 if (path_index < 0) {
1211 // path_index < 0 indicates that the class is intended for a custom loader
1212 // and should not be loaded by boot/platform/app loaders
1213 if (loader_data->is_builtin_class_loader_data()) {
1214 return false;
1215 } else {
1216 return true;
1217 }
1218 }
1219 SharedClassPathEntry* ent =
1220 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1221 if (!Universe::is_module_initialized()) {
1222 assert(ent != NULL && ent->is_modules_image(),
1223 "Loading non-bootstrap classes before the module system is initialized");
1224 assert(class_loader.is_null(), "sanity");
1225 return true;
1226 }
1227 // Get the pkg_entry from the classloader
1228 TempNewSymbol pkg_name = NULL;
1229 PackageEntry* pkg_entry = NULL;
1230 ModuleEntry* mod_entry = NULL;
1231 const char* pkg_string = NULL;
1232 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1233 if (pkg_name != NULL) {
1234 pkg_string = pkg_name->as_C_string();
1235 if (loader_data != NULL) {
1236 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1237 }
1238 if (pkg_entry != NULL) {
1239 mod_entry = pkg_entry->module();
1240 }
1241 }
1242
1243 // If the archived class is from a module that has been patched at runtime,
1244 // the class cannot be loaded from the archive.
1245 if (mod_entry != NULL && mod_entry->is_patched()) {
1246 return false;
1247 }
1248
1249 if (class_loader.is_null()) {
1250 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1251 // The NULL classloader can load archived class originated from the
1252 // "modules" jimage and the -Xbootclasspath/a. For class from the
1253 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1254 // by the NULL classloader.
1255 if (mod_entry != NULL) {
1256 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1257 // ModuleEntry's location agrees with the archived class' origination.
1258 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1259 return true; // Module class from the "module" jimage
1260 }
1261 }
1262
1263 // If the archived class is not from the "module" jimage, the class can be
1264 // loaded by the NULL classloader if
1265 //
1266 // 1. the class is from the unamed package
1267 // 2. or, the class is not from a module defined in the NULL classloader
1268 // 3. or, the class is from an unamed module
1269 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1270 // the class is from the -Xbootclasspath/a
1271 if (pkg_string == NULL ||
1272 pkg_entry == NULL ||
1273 pkg_entry->in_unnamed_module()) {
1274 assert(mod_entry == NULL ||
1275 mod_entry == loader_data->unnamed_module(),
1276 "the unnamed module is not defined in the classloader");
1277 return true;
1278 }
1279 }
1280 return false;
1281 } else {
1282 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1283 ik, class_loader, pkg_string, pkg_name,
1284 pkg_entry, mod_entry, CHECK_(false));
1285 return res;
1286 }
1287 }
1288
1289 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1290 Handle class_loader,
1291 Handle protection_domain, TRAPS) {
1292
1293 if (ik != NULL) {
1294 Symbol* class_name = ik->name();
1295
1296 bool visible = is_shared_class_visible(
1297 class_name, ik, class_loader, CHECK_NULL);
1298 if (!visible) {
1299 return NULL;
1300 }
1301
1302 // Resolve the superclass and interfaces. They must be the same
1303 // as in dump time, because the layout of <ik> depends on
1304 // the specific layout of ik->super() and ik->local_interfaces().
1305 //
1306 // If unexpected superclass or interfaces are found, we cannot
1307 // load <ik> from the shared archive.
1308
1309 if (ik->super() != NULL) {
1310 Symbol* cn = ik->super()->name();
1311 Klass *s = resolve_super_or_fail(class_name, cn,
1312 class_loader, protection_domain, true, CHECK_NULL);
1313 if (s != ik->super()) {
1314 // The dynamically resolved super class is not the same as the one we used during dump time,
1315 // so we cannot use ik.
1316 return NULL;
1317 } else {
1318 assert(s->is_shared(), "must be");
1319 }
1320 }
1321
1322 Array<Klass*>* interfaces = ik->local_interfaces();
1323 int num_interfaces = interfaces->length();
1324 for (int index = 0; index < num_interfaces; index++) {
1325 Klass* k = interfaces->at(index);
1326 Symbol* name = k->name();
1327 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1328 if (k != i) {
1329 // The dynamically resolved interface class is not the same as the one we used during dump time,
1330 // so we cannot use ik.
1331 return NULL;
1332 } else {
1333 assert(i->is_shared(), "must be");
1334 }
1335 }
1336
1337 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1338 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1339 if (new_ik != NULL) {
1340 // The class is changed by CFLH. Return the new class. The shared class is
1341 // not used.
1342 return new_ik;
1343 }
1344
1345 // Adjust methods to recover missing data. They need addresses for
1346 // interpreter entry points and their default native method address
1347 // must be reset.
1348
1349 // Updating methods must be done under a lock so multiple
1350 // threads don't update these in parallel
1351 //
1352 // Shared classes are all currently loaded by either the bootstrap or
1353 // internal parallel class loaders, so this will never cause a deadlock
1354 // on a custom class loader lock.
1355
1356 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1357 {
1358 HandleMark hm(THREAD);
1359 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1360 check_loader_lock_contention(lockObject, THREAD);
1361 ObjectLocker ol(lockObject, THREAD, true);
1362 // prohibited package check assumes all classes loaded from archive call
1363 // restore_unshareable_info which calls ik->set_package()
1364 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1365 }
1366
1367 ik->print_class_load_logging(loader_data, NULL, NULL);
1368
1369 // For boot loader, ensure that GetSystemPackage knows that a class in this
1370 // package was loaded.
1371 if (class_loader.is_null()) {
1372 int path_index = ik->shared_classpath_index();
1373 ResourceMark rm;
1374 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1375 }
1376
1377 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1378 // Only dump the classes that can be stored into CDS archive
1379 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1380 ResourceMark rm(THREAD);
1381 classlist_file->print_cr("%s", ik->name()->as_C_string());
1382 classlist_file->flush();
1383 }
1384 }
1385
1386 // notify a class loaded from shared object
1387 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1388 }
1389
1390 ik->set_has_passed_fingerprint_check(false);
1391 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1392 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1393 uint64_t cds_fp = ik->get_stored_fingerprint();
1394 if (aot_fp != 0 && aot_fp == cds_fp) {
1395 // This class matches with a class saved in an AOT library
1396 ik->set_has_passed_fingerprint_check(true);
1397 } else {
1398 ResourceMark rm;
1399 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1400 }
1401 }
1402 return ik;
1403 }
1404
1405 void SystemDictionary::clear_invoke_method_table() {
1406 SymbolPropertyEntry* spe = NULL;
1407 for (int index = 0; index < _invoke_method_table->table_size(); index++) {
1408 SymbolPropertyEntry* p = _invoke_method_table->bucket(index);
1409 while (p != NULL) {
1410 spe = p;
1411 p = p->next();
1412 _invoke_method_table->free_entry(spe);
1413 }
1414 }
1415 }
1416 #endif // INCLUDE_CDS
1417
1418 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1419
1420 if (class_loader.is_null()) {
1421 ResourceMark rm;
1422 PackageEntry* pkg_entry = NULL;
1423 bool search_only_bootloader_append = false;
1424 ClassLoaderData *loader_data = class_loader_data(class_loader);
1425
1426 // Find the package in the boot loader's package entry table.
1427 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1428 if (pkg_name != NULL) {
1429 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1430 }
1431
1432 // Prior to attempting to load the class, enforce the boot loader's
1433 // visibility boundaries.
1434 if (!Universe::is_module_initialized()) {
1435 // During bootstrapping, prior to module initialization, any
1436 // class attempting to be loaded must be checked against the
1437 // java.base packages in the boot loader's PackageEntryTable.
1438 // No class outside of java.base is allowed to be loaded during
1439 // this bootstrapping window.
1440 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1441 // Class is either in the unnamed package or in
1442 // a named package within the unnamed module. Either
1443 // case is outside of java.base, do not attempt to
1444 // load the class post java.base definition. If
1445 // java.base has not been defined, let the class load
1446 // and its package will be checked later by
1447 // ModuleEntryTable::verify_javabase_packages.
1448 if (ModuleEntryTable::javabase_defined()) {
1449 return NULL;
1450 }
1451 } else {
1452 // Check that the class' package is defined within java.base.
1453 ModuleEntry* mod_entry = pkg_entry->module();
1454 Symbol* mod_entry_name = mod_entry->name();
1455 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1456 return NULL;
1457 }
1458 }
1459 } else {
1460 // After the module system has been initialized, check if the class'
1461 // package is in a module defined to the boot loader.
1462 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1463 // Class is either in the unnamed package, in a named package
1464 // within a module not defined to the boot loader or in a
1465 // a named package within the unnamed module. In all cases,
1466 // limit visibility to search for the class only in the boot
1467 // loader's append path.
1468 search_only_bootloader_append = true;
1469 }
1470 }
1471
1472 // Prior to bootstrapping's module initialization, never load a class outside
1473 // of the boot loader's module path
1474 assert(Universe::is_module_initialized() ||
1475 !search_only_bootloader_append,
1476 "Attempt to load a class outside of boot loader's module path");
1477
1478 // Search the shared system dictionary for classes preloaded into the
1479 // shared spaces.
1480 InstanceKlass* k = NULL;
1481 {
1482 #if INCLUDE_CDS
1483 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1484 k = load_shared_class(class_name, class_loader, THREAD);
1485 #endif
1486 }
1487
1488 if (k == NULL) {
1489 // Use VM class loader
1490 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1491 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1492 }
1493
1494 // find_or_define_instance_class may return a different InstanceKlass
1495 if (k != NULL) {
1496 InstanceKlass* defined_k =
1497 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1498 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1499 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1500 assert(defined_k != NULL, "Should have a klass if there's no exception");
1501 loader_data->add_to_deallocate_list(k);
1502 k = defined_k;
1503 } else if (HAS_PENDING_EXCEPTION) {
1504 loader_data->add_to_deallocate_list(k);
1505 return NULL;
1506 }
1507 }
1508 return k;
1509 } else {
1510 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1511 ResourceMark rm(THREAD);
1512
1513 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1514 JavaThread* jt = (JavaThread*) THREAD;
1515
1516 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1517 ClassLoader::perf_app_classload_selftime(),
1518 ClassLoader::perf_app_classload_count(),
1519 jt->get_thread_stat()->perf_recursion_counts_addr(),
1520 jt->get_thread_stat()->perf_timers_addr(),
1521 PerfClassTraceTime::CLASS_LOAD);
1522
1523 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1524 // Translate to external class name format, i.e., convert '/' chars to '.'
1525 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1526
1527 JavaValue result(T_OBJECT);
1528
1529 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1530
1531 // Call public unsynchronized loadClass(String) directly for all class loaders.
1532 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1533 // acquire a class-name based lock rather than the class loader object lock.
1534 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1535 JavaCalls::call_virtual(&result,
1536 class_loader,
1537 spec_klass,
1538 vmSymbols::loadClass_name(),
1539 vmSymbols::string_class_signature(),
1540 string,
1541 CHECK_NULL);
1542
1543 assert(result.get_type() == T_OBJECT, "just checking");
1544 oop obj = (oop) result.get_jobject();
1545
1546 // Primitive classes return null since forName() can not be
1547 // used to obtain any of the Class objects representing primitives or void
1548 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1549 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1550 // For user defined Java class loaders, check that the name returned is
1551 // the same as that requested. This check is done for the bootstrap
1552 // loader when parsing the class file.
1553 if (class_name == k->name()) {
1554 return k;
1555 }
1556 }
1557 // Class is not found or has the wrong name, return NULL
1558 return NULL;
1559 }
1560 }
1561
1562 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1563
1564 HandleMark hm(THREAD);
1565 ClassLoaderData* loader_data = k->class_loader_data();
1566 Handle class_loader_h(THREAD, loader_data->class_loader());
1567
1568 // for bootstrap and other parallel classloaders don't acquire lock,
1569 // use placeholder token
1570 // If a parallelCapable class loader calls define_instance_class instead of
1571 // find_or_define_instance_class to get here, we have a timing
1572 // hole with systemDictionary updates and check_constraints
1573 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1574 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1575 compute_loader_lock_object(class_loader_h, THREAD)),
1576 "define called without lock");
1577 }
1578
1579 // Check class-loading constraints. Throw exception if violation is detected.
1580 // Grabs and releases SystemDictionary_lock
1581 // The check_constraints/find_class call and update_dictionary sequence
1582 // must be "atomic" for a specific class/classloader pair so we never
1583 // define two different instanceKlasses for that class/classloader pair.
1584 // Existing classloaders will call define_instance_class with the
1585 // classloader lock held
1586 // Parallel classloaders will call find_or_define_instance_class
1587 // which will require a token to perform the define class
1588 Symbol* name_h = k->name();
1589 Dictionary* dictionary = loader_data->dictionary();
1590 unsigned int d_hash = dictionary->compute_hash(name_h);
1591 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1592
1593 // Register class just loaded with class loader (placed in Vector)
1594 // Note we do this before updating the dictionary, as this can
1595 // fail with an OutOfMemoryError (if it does, we will *not* put this
1596 // class in the dictionary and will not update the class hierarchy).
1597 // JVMTI FollowReferences needs to find the classes this way.
1598 if (k->class_loader() != NULL) {
1599 methodHandle m(THREAD, Universe::loader_addClass_method());
1600 JavaValue result(T_VOID);
1601 JavaCallArguments args(class_loader_h);
1602 args.push_oop(Handle(THREAD, k->java_mirror()));
1603 JavaCalls::call(&result, m, &args, CHECK);
1604 }
1605
1606 // Add the new class. We need recompile lock during update of CHA.
1607 {
1608 unsigned int p_hash = placeholders()->compute_hash(name_h);
1609 int p_index = placeholders()->hash_to_index(p_hash);
1610
1611 MutexLocker mu_r(Compile_lock, THREAD);
1612
1613 // Add to class hierarchy, initialize vtables, and do possible
1614 // deoptimizations.
1615 add_to_hierarchy(k, CHECK); // No exception, but can block
1616
1617 // Add to systemDictionary - so other classes can see it.
1618 // Grabs and releases SystemDictionary_lock
1619 update_dictionary(d_hash, p_index, p_hash,
1620 k, class_loader_h, THREAD);
1621 }
1622 k->eager_initialize(THREAD);
1623
1624 // notify jvmti
1625 if (JvmtiExport::should_post_class_load()) {
1626 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1627 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1628
1629 }
1630 class_define_event(k, loader_data);
1631 }
1632
1633 // Support parallel classloading
1634 // All parallel class loaders, including bootstrap classloader
1635 // lock a placeholder entry for this class/class_loader pair
1636 // to allow parallel defines of different classes for this class loader
1637 // With AllowParallelDefine flag==true, in case they do not synchronize around
1638 // FindLoadedClass/DefineClass, calls, we check for parallel
1639 // loading for them, wait if a defineClass is in progress
1640 // and return the initial requestor's results
1641 // This flag does not apply to the bootstrap classloader.
1642 // With AllowParallelDefine flag==false, call through to define_instance_class
1643 // which will throw LinkageError: duplicate class definition.
1644 // False is the requested default.
1645 // For better performance, the class loaders should synchronize
1646 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1647 // potentially waste time reading and parsing the bytestream.
1648 // Note: VM callers should ensure consistency of k/class_name,class_loader
1649 // Be careful when modifying this code: once you have run
1650 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1651 // you need to find_and_remove it before returning.
1652 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1653 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1654 InstanceKlass* k, TRAPS) {
1655
1656 Symbol* name_h = k->name(); // passed in class_name may be null
1657 ClassLoaderData* loader_data = class_loader_data(class_loader);
1658 Dictionary* dictionary = loader_data->dictionary();
1659
1660 unsigned int d_hash = dictionary->compute_hash(name_h);
1661
1662 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1663 unsigned int p_hash = placeholders()->compute_hash(name_h);
1664 int p_index = placeholders()->hash_to_index(p_hash);
1665 PlaceholderEntry* probe;
1666
1667 {
1668 MutexLocker mu(SystemDictionary_lock, THREAD);
1669 // First check if class already defined
1670 if (is_parallelDefine(class_loader)) {
1671 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1672 if (check != NULL) {
1673 return check;
1674 }
1675 }
1676
1677 // Acquire define token for this class/classloader
1678 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1679 // Wait if another thread defining in parallel
1680 // All threads wait - even those that will throw duplicate class: otherwise
1681 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1682 // if other thread has not finished updating dictionary
1683 while (probe->definer() != NULL) {
1684 SystemDictionary_lock->wait();
1685 }
1686 // Only special cases allow parallel defines and can use other thread's results
1687 // Other cases fall through, and may run into duplicate defines
1688 // caught by finding an entry in the SystemDictionary
1689 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1690 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1691 SystemDictionary_lock->notify_all();
1692 #ifdef ASSERT
1693 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1694 assert(check != NULL, "definer missed recording success");
1695 #endif
1696 return probe->instance_klass();
1697 } else {
1698 // This thread will define the class (even if earlier thread tried and had an error)
1699 probe->set_definer(THREAD);
1700 }
1701 }
1702
1703 define_instance_class(k, THREAD);
1704
1705 Handle linkage_exception = Handle(); // null handle
1706
1707 // definer must notify any waiting threads
1708 {
1709 MutexLocker mu(SystemDictionary_lock, THREAD);
1710 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1711 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1712 if (probe != NULL) {
1713 if (HAS_PENDING_EXCEPTION) {
1714 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1715 CLEAR_PENDING_EXCEPTION;
1716 } else {
1717 probe->set_instance_klass(k);
1718 }
1719 probe->set_definer(NULL);
1720 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1721 SystemDictionary_lock->notify_all();
1722 }
1723 }
1724
1725 // Can't throw exception while holding lock due to rank ordering
1726 if (linkage_exception() != NULL) {
1727 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1728 }
1729
1730 return k;
1731 }
1732
1733 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1734 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1735 if (class_loader.is_null()) {
1736 return Handle(THREAD, _system_loader_lock_obj);
1737 } else {
1738 return class_loader;
1739 }
1740 }
1741
1742 // This method is added to check how often we have to wait to grab loader
1743 // lock. The results are being recorded in the performance counters defined in
1744 // ClassLoader::_sync_systemLoaderLockContentionRate and
1745 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1746 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1747 if (!UsePerfData) {
1748 return;
1749 }
1750
1751 assert(!loader_lock.is_null(), "NULL lock object");
1752
1753 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1754 == ObjectSynchronizer::owner_other) {
1755 // contention will likely happen, so increment the corresponding
1756 // contention counter.
1757 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1758 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1759 } else {
1760 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1761 }
1762 }
1763 }
1764
1765 // ----------------------------------------------------------------------------
1766 // Lookup
1767
1768 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1769 Symbol* class_name,
1770 Dictionary* dictionary) {
1771 assert_locked_or_safepoint(SystemDictionary_lock);
1772 int index = dictionary->hash_to_index(hash);
1773 return dictionary->find_class(index, hash, class_name);
1774 }
1775
1776
1777 // Basic find on classes in the midst of being loaded
1778 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1779 ClassLoaderData* loader_data) {
1780 assert_locked_or_safepoint(SystemDictionary_lock);
1781 unsigned int p_hash = placeholders()->compute_hash(class_name);
1782 int p_index = placeholders()->hash_to_index(p_hash);
1783 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1784 }
1785
1786
1787 // Used for assertions and verification only
1788 // Precalculating the hash and index is an optimization because there are many lookups
1789 // before adding the class.
1790 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1791 assert_locked_or_safepoint(SystemDictionary_lock);
1792 #ifndef ASSERT
1793 guarantee(VerifyBeforeGC ||
1794 VerifyDuringGC ||
1795 VerifyBeforeExit ||
1796 VerifyDuringStartup ||
1797 VerifyAfterGC, "too expensive");
1798 #endif
1799
1800 Dictionary* dictionary = loader_data->dictionary();
1801 unsigned int d_hash = dictionary->compute_hash(class_name);
1802 return find_class(d_hash, class_name, dictionary);
1803 }
1804
1805
1806 // ----------------------------------------------------------------------------
1807 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1808 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1809 // before a new class is used.
1810
1811 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1812 assert(k != NULL, "just checking");
1813 assert_locked_or_safepoint(Compile_lock);
1814
1815 // Link into hierachy. Make sure the vtables are initialized before linking into
1816 k->append_to_sibling_list(); // add to superklass/sibling list
1817 k->process_interfaces(THREAD); // handle all "implements" declarations
1818 k->set_init_state(InstanceKlass::loaded);
1819 // Now flush all code that depended on old class hierarchy.
1820 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1821 // Also, first reinitialize vtable because it may have gotten out of synch
1822 // while the new class wasn't connected to the class hierarchy.
1823 CodeCache::flush_dependents_on(k);
1824 }
1825
1826 // ----------------------------------------------------------------------------
1827 // GC support
1828
1829 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1830 roots_oops_do(blk, NULL);
1831 }
1832
1833
1834 #ifdef ASSERT
1835 class VerifySDReachableAndLiveClosure : public OopClosure {
1836 private:
1837 BoolObjectClosure* _is_alive;
1838
1839 template <class T> void do_oop_work(T* p) {
1840 oop obj = RawAccess<>::oop_load(p);
1841 guarantee(_is_alive->do_object_b(obj), "Oop in protection domain cache table must be live");
1842 }
1843
1844 public:
1845 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1846
1847 virtual void do_oop(oop* p) { do_oop_work(p); }
1848 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1849 };
1850 #endif
1851
1852 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1853 // Note: anonymous classes are not in the SD.
1854 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1855 GCTimer* gc_timer,
1856 bool do_cleaning) {
1857
1858 {
1859 GCTraceTime(Debug, gc, phases) t("SystemDictionary WeakHandle cleaning", gc_timer);
1860 vm_weak_oop_storage()->weak_oops_do(is_alive, &do_nothing_cl);
1861 }
1862
1863 bool unloading_occurred;
1864 {
1865 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1866
1867 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1868 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1869 do_cleaning);
1870 }
1871
1872 if (unloading_occurred) {
1873 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1874 constraints()->purge_loader_constraints();
1875 resolution_errors()->purge_resolution_errors();
1876 }
1877
1878 {
1879 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1880 // Oops referenced by the protection domain cache table may get unreachable independently
1881 // of the class loader (eg. cached protection domain oops). So we need to
1882 // explicitly unlink them here.
1883 _pd_cache_table->unlink(is_alive);
1884
1885 #ifdef ASSERT
1886 VerifySDReachableAndLiveClosure cl(is_alive);
1887 _pd_cache_table->oops_do(&cl);
1888 #endif
1889 }
1890
1891 if (do_cleaning) {
1892 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1893 ResolvedMethodTable::unlink(is_alive);
1894 }
1895
1896 return unloading_occurred;
1897 }
1898
1899 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1900 strong->do_oop(&_java_system_loader);
1901 strong->do_oop(&_java_platform_loader);
1902 strong->do_oop(&_system_loader_lock_obj);
1903 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1904
1905 // Do strong roots marking if the closures are the same.
1906 if (strong == weak || !ClassUnloading) {
1907 // Only the protection domain oops contain references into the heap. Iterate
1908 // over all of them.
1909 _pd_cache_table->oops_do(strong);
1910 vm_weak_oop_storage()->oops_do(strong);
1911 } else {
1912 if (weak != NULL) {
1913 _pd_cache_table->oops_do(weak);
1914 vm_weak_oop_storage()->oops_do(weak);
1915 }
1916 }
1917
1918 // Visit extra methods
1919 invoke_method_table()->oops_do(strong);
1920
1921 if (weak != NULL) {
1922 ResolvedMethodTable::oops_do(weak);
1923 }
1924 }
1925
1926 void SystemDictionary::oops_do(OopClosure* f) {
1927 f->do_oop(&_java_system_loader);
1928 f->do_oop(&_java_platform_loader);
1929 f->do_oop(&_system_loader_lock_obj);
1930 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1931
1932 // Only the protection domain oops contain references into the heap. Iterate
1933 // over all of them.
1934 _pd_cache_table->oops_do(f);
1935
1936 // Visit extra methods
1937 invoke_method_table()->oops_do(f);
1938
1939 ResolvedMethodTable::oops_do(f);
1940
1941 vm_weak_oop_storage()->oops_do(f);
1942 }
1943
1944 // CDS: scan and relocate all classes in the system dictionary.
1945 void SystemDictionary::classes_do(MetaspaceClosure* it) {
1946 ClassLoaderData::the_null_class_loader_data()->dictionary()->classes_do(it);
1947 }
1948
1949 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1950 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1951 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1952 it->push(well_known_klass_addr((WKID)id));
1953 }
1954 }
1955
1956 void SystemDictionary::methods_do(void f(Method*)) {
1957 // Walk methods in loaded classes
1958 ClassLoaderDataGraph::methods_do(f);
1959 // Walk method handle intrinsics
1960 invoke_method_table()->methods_do(f);
1961 }
1962
1963 class RemoveClassesClosure : public CLDClosure {
1964 public:
1965 void do_cld(ClassLoaderData* cld) {
1966 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
1967 cld->dictionary()->remove_classes_in_error_state();
1968 }
1969 }
1970 };
1971
1972 void SystemDictionary::remove_classes_in_error_state() {
1973 ClassLoaderData::the_null_class_loader_data()->dictionary()->remove_classes_in_error_state();
1974 RemoveClassesClosure rcc;
1975 ClassLoaderDataGraph::cld_do(&rcc);
1976 }
1977
1978 // ----------------------------------------------------------------------------
1979 // Lazily load klasses
1980
1981 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1982 // if multiple threads calling this function, only one thread will load
1983 // the class. The other threads will find the loaded version once the
1984 // class is loaded.
1985 Klass* aos = _abstract_ownable_synchronizer_klass;
1986 if (aos == NULL) {
1987 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1988 // Force a fence to prevent any read before the write completes
1989 OrderAccess::fence();
1990 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
1991 }
1992 }
1993
1994 // ----------------------------------------------------------------------------
1995 // Initialization
1996
1997 void SystemDictionary::initialize(TRAPS) {
1998 // Allocate arrays
1999 _placeholders = new PlaceholderTable(_placeholder_table_size);
2000 _number_of_modifications = 0;
2001 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2002 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2003 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2004 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2005
2006 // Allocate private object used as system class loader lock
2007 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2008 // Initialize basic classes
2009 initialize_preloaded_classes(CHECK);
2010 }
2011
2012 // Compact table of directions on the initialization of klasses:
2013 static const short wk_init_info[] = {
2014 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2015 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2016 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2017 | (int)SystemDictionary::option ),
2018 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2019 #undef WK_KLASS_INIT_INFO
2020 0
2021 };
2022
2023 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2024 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2025 int info = wk_init_info[id - FIRST_WKID];
2026 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2027 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2028 InstanceKlass** klassp = &_well_known_klasses[id];
2029
2030 bool must_load;
2031 #if INCLUDE_JVMCI
2032 if (EnableJVMCI) {
2033 // If JVMCI is enabled we require its classes to be found.
2034 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2035 } else
2036 #endif
2037 {
2038 must_load = (init_opt < SystemDictionary::Opt);
2039 }
2040
2041 if ((*klassp) == NULL) {
2042 Klass* k;
2043 if (must_load) {
2044 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2045 } else {
2046 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2047 }
2048 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2049 }
2050 return ((*klassp) != NULL);
2051 }
2052
2053 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2054 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2055 for (int id = (int)start_id; id < (int)limit_id; id++) {
2056 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2057 int info = wk_init_info[id - FIRST_WKID];
2058 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2059 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2060
2061 initialize_wk_klass((WKID)id, opt, CHECK);
2062 }
2063
2064 // move the starting value forward to the limit:
2065 start_id = limit_id;
2066 }
2067
2068 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2069 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2070
2071 // Create the ModuleEntry for java.base. This call needs to be done here,
2072 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2073 ClassLoader::classLoader_init2(CHECK);
2074
2075 // Preload commonly used klasses
2076 WKID scan = FIRST_WKID;
2077 // first do Object, then String, Class
2078 #if INCLUDE_CDS
2079 if (UseSharedSpaces) {
2080 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2081 // Initialize the constant pool for the Object_class
2082 Object_klass()->constants()->restore_unshareable_info(CHECK);
2083 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2084 } else
2085 #endif
2086 {
2087 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2088 }
2089
2090 // Calculate offsets for String and Class classes since they are loaded and
2091 // can be used after this point.
2092 java_lang_String::compute_offsets();
2093 java_lang_Class::compute_offsets();
2094
2095 // Fixup mirrors for classes loaded before java.lang.Class.
2096 // These calls iterate over the objects currently in the perm gen
2097 // so calling them at this point is matters (not before when there
2098 // are fewer objects and not later after there are more objects
2099 // in the perm gen.
2100 Universe::initialize_basic_type_mirrors(CHECK);
2101 Universe::fixup_mirrors(CHECK);
2102
2103 // do a bunch more:
2104 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2105
2106 // Preload ref klasses and set reference types
2107 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2108 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2109
2110 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2111 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2112 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2113 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2114 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2115
2116 // JSR 292 classes
2117 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2118 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2119 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2120 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2121 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2122
2123 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2124 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2125 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2126 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2127 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2128 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2129 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2130 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2131 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2132 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2133
2134 { // Compute whether we should use checkPackageAccess or NOT
2135 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2136 _has_checkPackageAccess = (method != NULL);
2137 }
2138 }
2139
2140 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2141 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2142 BasicType SystemDictionary::box_klass_type(Klass* k) {
2143 assert(k != NULL, "");
2144 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2145 if (_box_klasses[i] == k)
2146 return (BasicType)i;
2147 }
2148 return T_OBJECT;
2149 }
2150
2151 // Constraints on class loaders. The details of the algorithm can be
2152 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2153 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2154 // that the dictionary needs to maintain a set of contraints that
2155 // must be satisfied by all classes in the dictionary.
2156 // if defining is true, then LinkageError if already in dictionary
2157 // if initiating loader, then ok if InstanceKlass matches existing entry
2158
2159 void SystemDictionary::check_constraints(unsigned int d_hash,
2160 InstanceKlass* k,
2161 Handle class_loader,
2162 bool defining,
2163 TRAPS) {
2164 ResourceMark rm(THREAD);
2165 stringStream ss;
2166 bool throwException = false;
2167
2168 const char *linkage_error1 = NULL;
2169 const char *linkage_error2 = NULL;
2170 const char *linkage_error3 = "";
2171 // Remember the loader of the similar class that is already loaded.
2172 const char *existing_klass_loader_name = "";
2173
2174 {
2175 Symbol* name = k->name();
2176 ClassLoaderData *loader_data = class_loader_data(class_loader);
2177
2178 MutexLocker mu(SystemDictionary_lock, THREAD);
2179
2180 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2181 if (check != NULL) {
2182 // If different InstanceKlass - duplicate class definition,
2183 // else - ok, class loaded by a different thread in parallel.
2184 // We should only have found it if it was done loading and ok to use.
2185 // The dictionary only holds instance classes, placeholders
2186 // also hold array classes.
2187
2188 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2189 if ((defining == true) || (k != check)) {
2190 throwException = true;
2191 ss.print("loader %s", java_lang_ClassLoader::describe_external(class_loader()));
2192 ss.print(" attempted duplicate %s definition for %s.",
2193 k->external_kind(), k->external_name());
2194 } else {
2195 return;
2196 }
2197 }
2198
2199 #ifdef ASSERT
2200 Symbol* ph_check = find_placeholder(name, loader_data);
2201 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2202 #endif
2203
2204 if (throwException == false) {
2205 if (constraints()->check_or_update(k, class_loader, name) == false) {
2206 throwException = true;
2207 ss.print("loader constraint violation: loader %s",
2208 java_lang_ClassLoader::describe_external(class_loader()));
2209 ss.print(" wants to load %s %s.",
2210 k->external_kind(), k->external_name());
2211 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2212 if (existing_klass->class_loader() != class_loader()) {
2213 ss.print(" A different %s with the same name was previously loaded by %s.",
2214 existing_klass->external_kind(),
2215 java_lang_ClassLoader::describe_external(existing_klass->class_loader()));
2216 }
2217 }
2218 }
2219 }
2220
2221 // Throw error now if needed (cannot throw while holding
2222 // SystemDictionary_lock because of rank ordering)
2223 if (throwException == true) {
2224 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2225 }
2226 }
2227
2228 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2229 // have been called.
2230 void SystemDictionary::update_dictionary(unsigned int d_hash,
2231 int p_index, unsigned int p_hash,
2232 InstanceKlass* k,
2233 Handle class_loader,
2234 TRAPS) {
2235 // Compile_lock prevents systemDictionary updates during compilations
2236 assert_locked_or_safepoint(Compile_lock);
2237 Symbol* name = k->name();
2238 ClassLoaderData *loader_data = class_loader_data(class_loader);
2239
2240 {
2241 MutexLocker mu1(SystemDictionary_lock, THREAD);
2242
2243 // See whether biased locking is enabled and if so set it for this
2244 // klass.
2245 // Note that this must be done past the last potential blocking
2246 // point / safepoint. We enable biased locking lazily using a
2247 // VM_Operation to iterate the SystemDictionary and installing the
2248 // biasable mark word into each InstanceKlass's prototype header.
2249 // To avoid race conditions where we accidentally miss enabling the
2250 // optimization for one class in the process of being added to the
2251 // dictionary, we must not safepoint after the test of
2252 // BiasedLocking::enabled().
2253 if (UseBiasedLocking && BiasedLocking::enabled()) {
2254 // Set biased locking bit for all loaded classes; it will be
2255 // cleared if revocation occurs too often for this type
2256 // NOTE that we must only do this when the class is initally
2257 // defined, not each time it is referenced from a new class loader
2258 if (oopDesc::equals(k->class_loader(), class_loader())) {
2259 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2260 }
2261 }
2262
2263 // Make a new dictionary entry.
2264 Dictionary* dictionary = loader_data->dictionary();
2265 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2266 if (sd_check == NULL) {
2267 dictionary->add_klass(d_hash, name, k);
2268 notice_modification();
2269 }
2270 #ifdef ASSERT
2271 sd_check = find_class(d_hash, name, dictionary);
2272 assert (sd_check != NULL, "should have entry in dictionary");
2273 // Note: there may be a placeholder entry: for circularity testing
2274 // or for parallel defines
2275 #endif
2276 SystemDictionary_lock->notify_all();
2277 }
2278 }
2279
2280
2281 // Try to find a class name using the loader constraints. The
2282 // loader constraints might know about a class that isn't fully loaded
2283 // yet and these will be ignored.
2284 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2285 Symbol* class_name, Handle class_loader, TRAPS) {
2286
2287 // First see if it has been loaded directly.
2288 // Force the protection domain to be null. (This removes protection checks.)
2289 Handle no_protection_domain;
2290 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2291 no_protection_domain, CHECK_NULL);
2292 if (klass != NULL)
2293 return klass;
2294
2295 // Now look to see if it has been loaded elsewhere, and is subject to
2296 // a loader constraint that would require this loader to return the
2297 // klass that is already loaded.
2298 if (FieldType::is_array(class_name)) {
2299 // For array classes, their Klass*s are not kept in the
2300 // constraint table. The element Klass*s are.
2301 FieldArrayInfo fd;
2302 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2303 if (t != T_OBJECT) {
2304 klass = Universe::typeArrayKlassObj(t);
2305 } else {
2306 MutexLocker mu(SystemDictionary_lock, THREAD);
2307 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2308 }
2309 // If element class already loaded, allocate array klass
2310 if (klass != NULL) {
2311 klass = klass->array_klass_or_null(fd.dimension());
2312 }
2313 } else {
2314 MutexLocker mu(SystemDictionary_lock, THREAD);
2315 // Non-array classes are easy: simply check the constraint table.
2316 klass = constraints()->find_constrained_klass(class_name, class_loader);
2317 }
2318
2319 return klass;
2320 }
2321
2322
2323 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2324 Handle class_loader1,
2325 Handle class_loader2,
2326 Thread* THREAD) {
2327 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2328 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2329
2330 Symbol* constraint_name = NULL;
2331 if (!FieldType::is_array(class_name)) {
2332 constraint_name = class_name;
2333 } else {
2334 // For array classes, their Klass*s are not kept in the
2335 // constraint table. The element classes are.
2336 FieldArrayInfo fd;
2337 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2338 // primitive types always pass
2339 if (t != T_OBJECT) {
2340 return true;
2341 } else {
2342 constraint_name = fd.object_key();
2343 }
2344 }
2345
2346 Dictionary* dictionary1 = loader_data1->dictionary();
2347 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2348
2349 Dictionary* dictionary2 = loader_data2->dictionary();
2350 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2351
2352 {
2353 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2354 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2355 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2356 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2357 klass2, class_loader2);
2358 }
2359 }
2360
2361 // Add entry to resolution error table to record the error when the first
2362 // attempt to resolve a reference to a class has failed.
2363 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2364 Symbol* error, Symbol* message) {
2365 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2366 int index = resolution_errors()->hash_to_index(hash);
2367 {
2368 MutexLocker ml(SystemDictionary_lock, Thread::current());
2369 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2370 }
2371 }
2372
2373 // Delete a resolution error for RedefineClasses for a constant pool is going away
2374 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2375 resolution_errors()->delete_entry(pool);
2376 }
2377
2378 // Lookup resolution error table. Returns error if found, otherwise NULL.
2379 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2380 Symbol** message) {
2381 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2382 int index = resolution_errors()->hash_to_index(hash);
2383 {
2384 MutexLocker ml(SystemDictionary_lock, Thread::current());
2385 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2386 if (entry != NULL) {
2387 *message = entry->message();
2388 return entry->error();
2389 } else {
2390 return NULL;
2391 }
2392 }
2393 }
2394
2395
2396 // Signature constraints ensure that callers and callees agree about
2397 // the meaning of type names in their signatures. This routine is the
2398 // intake for constraints. It collects them from several places:
2399 //
2400 // * LinkResolver::resolve_method (if check_access is true) requires
2401 // that the resolving class (the caller) and the defining class of
2402 // the resolved method (the callee) agree on each type in the
2403 // method's signature.
2404 //
2405 // * LinkResolver::resolve_interface_method performs exactly the same
2406 // checks.
2407 //
2408 // * LinkResolver::resolve_field requires that the constant pool
2409 // attempting to link to a field agree with the field's defining
2410 // class about the type of the field signature.
2411 //
2412 // * klassVtable::initialize_vtable requires that, when a class
2413 // overrides a vtable entry allocated by a superclass, that the
2414 // overriding method (i.e., the callee) agree with the superclass
2415 // on each type in the method's signature.
2416 //
2417 // * klassItable::initialize_itable requires that, when a class fills
2418 // in its itables, for each non-abstract method installed in an
2419 // itable, the method (i.e., the callee) agree with the interface
2420 // on each type in the method's signature.
2421 //
2422 // All those methods have a boolean (check_access, checkconstraints)
2423 // which turns off the checks. This is used from specialized contexts
2424 // such as bootstrapping, dumping, and debugging.
2425 //
2426 // No direct constraint is placed between the class and its
2427 // supertypes. Constraints are only placed along linked relations
2428 // between callers and callees. When a method overrides or implements
2429 // an abstract method in a supertype (superclass or interface), the
2430 // constraints are placed as if the supertype were the caller to the
2431 // overriding method. (This works well, since callers to the
2432 // supertype have already established agreement between themselves and
2433 // the supertype.) As a result of all this, a class can disagree with
2434 // its supertype about the meaning of a type name, as long as that
2435 // class neither calls a relevant method of the supertype, nor is
2436 // called (perhaps via an override) from the supertype.
2437 //
2438 //
2439 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2440 //
2441 // Make sure all class components (including arrays) in the given
2442 // signature will be resolved to the same class in both loaders.
2443 // Returns the name of the type that failed a loader constraint check, or
2444 // NULL if no constraint failed. No exception except OOME is thrown.
2445 // Arrays are not added to the loader constraint table, their elements are.
2446 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2447 Handle loader1, Handle loader2,
2448 bool is_method, TRAPS) {
2449 // Nothing to do if loaders are the same.
2450 if (oopDesc::equals(loader1(), loader2())) {
2451 return NULL;
2452 }
2453
2454 SignatureStream sig_strm(signature, is_method);
2455 while (!sig_strm.is_done()) {
2456 if (sig_strm.is_object()) {
2457 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2458 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2459 return sig;
2460 }
2461 }
2462 sig_strm.next();
2463 }
2464 return NULL;
2465 }
2466
2467
2468 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2469 Symbol* signature,
2470 TRAPS) {
2471 methodHandle empty;
2472 assert(MethodHandles::is_signature_polymorphic(iid) &&
2473 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2474 iid != vmIntrinsics::_invokeGeneric,
2475 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2476
2477 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2478 int index = invoke_method_table()->hash_to_index(hash);
2479 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2480 methodHandle m;
2481 if (spe == NULL || spe->method() == NULL) {
2482 spe = NULL;
2483 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2484 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2485 if (!Arguments::is_interpreter_only()) {
2486 // Generate a compiled form of the MH intrinsic.
2487 AdapterHandlerLibrary::create_native_wrapper(m);
2488 // Check if have the compiled code.
2489 if (!m->has_compiled_code()) {
2490 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2491 "Out of space in CodeCache for method handle intrinsic", empty);
2492 }
2493 }
2494 // Now grab the lock. We might have to throw away the new method,
2495 // if a racing thread has managed to install one at the same time.
2496 {
2497 MutexLocker ml(SystemDictionary_lock, THREAD);
2498 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2499 if (spe == NULL)
2500 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2501 if (spe->method() == NULL)
2502 spe->set_method(m());
2503 }
2504 }
2505
2506 assert(spe != NULL && spe->method() != NULL, "");
2507 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2508 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2509 "MH intrinsic invariant");
2510 return spe->method();
2511 }
2512
2513 // Helper for unpacking the return value from linkMethod and linkCallSite.
2514 static methodHandle unpack_method_and_appendix(Handle mname,
2515 Klass* accessing_klass,
2516 objArrayHandle appendix_box,
2517 Handle* appendix_result,
2518 TRAPS) {
2519 methodHandle empty;
2520 if (mname.not_null()) {
2521 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2522 if (m != NULL) {
2523 oop appendix = appendix_box->obj_at(0);
2524 if (TraceMethodHandles) {
2525 #ifndef PRODUCT
2526 ttyLocker ttyl;
2527 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2528 m->print();
2529 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2530 tty->cr();
2531 #endif //PRODUCT
2532 }
2533 (*appendix_result) = Handle(THREAD, appendix);
2534 // the target is stored in the cpCache and if a reference to this
2535 // MemberName is dropped we need a way to make sure the
2536 // class_loader containing this method is kept alive.
2537 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2538 this_key->record_dependency(m->method_holder());
2539 return methodHandle(THREAD, m);
2540 }
2541 }
2542 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2543 return empty;
2544 }
2545
2546 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2547 Symbol* name,
2548 Symbol* signature,
2549 Klass* accessing_klass,
2550 Handle *appendix_result,
2551 Handle *method_type_result,
2552 TRAPS) {
2553 methodHandle empty;
2554 assert(THREAD->can_call_java() ,"");
2555 Handle method_type =
2556 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2557
2558 int ref_kind = JVM_REF_invokeVirtual;
2559 oop name_oop = StringTable::intern(name, CHECK_(empty));
2560 Handle name_str (THREAD, name_oop);
2561 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2562 assert(appendix_box->obj_at(0) == NULL, "");
2563
2564 // This should not happen. JDK code should take care of that.
2565 if (accessing_klass == NULL || method_type.is_null()) {
2566 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2567 }
2568
2569 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2570 JavaCallArguments args;
2571 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2572 args.push_int(ref_kind);
2573 args.push_oop(Handle(THREAD, klass->java_mirror()));
2574 args.push_oop(name_str);
2575 args.push_oop(method_type);
2576 args.push_oop(appendix_box);
2577 JavaValue result(T_OBJECT);
2578 JavaCalls::call_static(&result,
2579 SystemDictionary::MethodHandleNatives_klass(),
2580 vmSymbols::linkMethod_name(),
2581 vmSymbols::linkMethod_signature(),
2582 &args, CHECK_(empty));
2583 Handle mname(THREAD, (oop) result.get_jobject());
2584 (*method_type_result) = method_type;
2585 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2586 }
2587
2588 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2589 // We must ensure that all class loaders everywhere will reach this class, for any client.
2590 // This is a safe bet for public classes in java.lang, such as Object and String.
2591 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2592 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2593 static bool is_always_visible_class(oop mirror) {
2594 Klass* klass = java_lang_Class::as_Klass(mirror);
2595 if (klass->is_objArray_klass()) {
2596 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2597 }
2598 if (klass->is_typeArray_klass()) {
2599 return true; // primitive array
2600 }
2601 assert(klass->is_instance_klass(), "%s", klass->external_name());
2602 return klass->is_public() &&
2603 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2604 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2605 }
2606
2607
2608 // Return the Java mirror (java.lang.Class instance) for a single-character
2609 // descriptor. This result, when available, is the same as produced by the
2610 // heavier API point of the same name that takes a Symbol.
2611 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2612 return java_lang_Class::primitive_mirror(char2type(signature_char));
2613 }
2614
2615 // Find or construct the Java mirror (java.lang.Class instance) for a
2616 // for the given field type signature, as interpreted relative to the
2617 // given class loader. Handles primitives, void, references, arrays,
2618 // and all other reflectable types, except method types.
2619 // N.B. Code in reflection should use this entry point.
2620 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2621 Klass* accessing_klass,
2622 Handle class_loader,
2623 Handle protection_domain,
2624 SignatureStream::FailureMode failure_mode,
2625 TRAPS) {
2626 Handle empty;
2627
2628 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2629 "one or the other, or perhaps neither");
2630
2631 Symbol* type = signature;
2632
2633 // What we have here must be a valid field descriptor,
2634 // and all valid field descriptors are supported.
2635 // Produce the same java.lang.Class that reflection reports.
2636 if (type->utf8_length() == 1) {
2637
2638 // It's a primitive. (Void has a primitive mirror too.)
2639 char ch = (char) type->byte_at(0);
2640 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2641 return Handle(THREAD, find_java_mirror_for_type(ch));
2642
2643 } else if (FieldType::is_obj(type) || FieldType::is_array(type)) {
2644
2645 // It's a reference type.
2646 if (accessing_klass != NULL) {
2647 class_loader = Handle(THREAD, accessing_klass->class_loader());
2648 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2649 }
2650 Klass* constant_type_klass;
2651 if (failure_mode == SignatureStream::ReturnNull) {
2652 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2653 CHECK_(empty));
2654 } else {
2655 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2656 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2657 throw_error, CHECK_(empty));
2658 }
2659 if (constant_type_klass == NULL) {
2660 return Handle(); // report failure this way
2661 }
2662 Handle mirror(THREAD, constant_type_klass->java_mirror());
2663
2664 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2665 if (accessing_klass != NULL) {
2666 Klass* sel_klass = constant_type_klass;
2667 bool fold_type_to_class = true;
2668 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2669 fold_type_to_class, CHECK_(empty));
2670 }
2671
2672 return mirror;
2673
2674 }
2675
2676 // Fall through to an error.
2677 assert(false, "unsupported mirror syntax");
2678 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2679 }
2680
2681
2682 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2683 // signature, as interpreted relative to the given class loader.
2684 // Because of class loader constraints, all method handle usage must be
2685 // consistent with this loader.
2686 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2687 Klass* accessing_klass,
2688 TRAPS) {
2689 Handle empty;
2690 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2691 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2692 int index = invoke_method_table()->hash_to_index(hash);
2693 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2694 if (spe != NULL && spe->method_type() != NULL) {
2695 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2696 return Handle(THREAD, spe->method_type());
2697 } else if (!THREAD->can_call_java()) {
2698 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2699 return Handle(); // do not attempt from within compiler, unless it was cached
2700 }
2701
2702 Handle class_loader, protection_domain;
2703 if (accessing_klass != NULL) {
2704 class_loader = Handle(THREAD, accessing_klass->class_loader());
2705 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2706 }
2707 bool can_be_cached = true;
2708 int npts = ArgumentCount(signature).size();
2709 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2710 int arg = 0;
2711 Handle rt; // the return type from the signature
2712 ResourceMark rm(THREAD);
2713 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2714 oop mirror = NULL;
2715 if (can_be_cached) {
2716 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2717 mirror = ss.as_java_mirror(Handle(), Handle(),
2718 SignatureStream::ReturnNull, CHECK_(empty));
2719 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2720 // Fall back to accessing_klass context.
2721 can_be_cached = false;
2722 }
2723 }
2724 if (!can_be_cached) {
2725 // Resolve, throwing a real error if it doesn't work.
2726 mirror = ss.as_java_mirror(class_loader, protection_domain,
2727 SignatureStream::NCDFError, CHECK_(empty));
2728 }
2729 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2730 if (ss.at_return_type())
2731 rt = Handle(THREAD, mirror);
2732 else
2733 pts->obj_at_put(arg++, mirror);
2734
2735 // Check accessibility.
2736 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2737 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2738 mirror = NULL; // safety
2739 // Emulate ConstantPool::verify_constant_pool_resolve.
2740 bool fold_type_to_class = true;
2741 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2742 fold_type_to_class, CHECK_(empty));
2743 }
2744 }
2745 assert(arg == npts, "");
2746
2747 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2748 JavaCallArguments args(Handle(THREAD, rt()));
2749 args.push_oop(pts);
2750 JavaValue result(T_OBJECT);
2751 JavaCalls::call_static(&result,
2752 SystemDictionary::MethodHandleNatives_klass(),
2753 vmSymbols::findMethodHandleType_name(),
2754 vmSymbols::findMethodHandleType_signature(),
2755 &args, CHECK_(empty));
2756 Handle method_type(THREAD, (oop) result.get_jobject());
2757
2758 if (can_be_cached) {
2759 // We can cache this MethodType inside the JVM.
2760 MutexLocker ml(SystemDictionary_lock, THREAD);
2761 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2762 if (spe == NULL)
2763 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2764 if (spe->method_type() == NULL) {
2765 spe->set_method_type(method_type());
2766 }
2767 }
2768
2769 // report back to the caller with the MethodType
2770 return method_type;
2771 }
2772
2773 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2774 Klass* accessing_klass,
2775 TRAPS) {
2776 Handle empty;
2777 ResourceMark rm(THREAD);
2778 SignatureStream ss(signature, /*is_method=*/ false);
2779 if (!ss.is_done()) {
2780 Handle class_loader, protection_domain;
2781 if (accessing_klass != NULL) {
2782 class_loader = Handle(THREAD, accessing_klass->class_loader());
2783 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2784 }
2785 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2786 ss.next();
2787 if (ss.is_done()) {
2788 return Handle(THREAD, mirror);
2789 }
2790 }
2791 return empty;
2792 }
2793
2794 // Ask Java code to find or construct a method handle constant.
2795 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2796 int ref_kind, //e.g., JVM_REF_invokeVirtual
2797 Klass* callee,
2798 Symbol* name,
2799 Symbol* signature,
2800 TRAPS) {
2801 Handle empty;
2802 if (caller == NULL) {
2803 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2804 }
2805 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2806 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2807
2808 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2809 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2810 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2811 java_lang_invoke_MemberName::set_name (mname(), name_str());
2812 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2813 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2814
2815 if (ref_kind == JVM_REF_invokeVirtual &&
2816 callee->name() == vmSymbols::java_lang_invoke_MethodHandle() &&
2817 (name == vmSymbols::invoke_name() || name == vmSymbols::invokeExact_name())) {
2818 // Skip resolution for j.l.i.MethodHandle.invoke()/invokeExact().
2819 // They are public signature polymorphic methods, but require appendix argument
2820 // which MemberName resolution doesn't handle. There's special logic on JDK side to handle them
2821 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2822 } else {
2823 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2824 }
2825
2826 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2827 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2828
2829 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2830 JavaCallArguments args;
2831 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2832 args.push_int(ref_kind);
2833 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2834 args.push_oop(name_str);
2835 args.push_oop(type);
2836 JavaValue result(T_OBJECT);
2837 JavaCalls::call_static(&result,
2838 SystemDictionary::MethodHandleNatives_klass(),
2839 vmSymbols::linkMethodHandleConstant_name(),
2840 vmSymbols::linkMethodHandleConstant_signature(),
2841 &args, CHECK_(empty));
2842 return Handle(THREAD, (oop) result.get_jobject());
2843 }
2844
2845 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2846 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2847 int condy_index,
2848 Handle bootstrap_specifier,
2849 Symbol* name,
2850 Symbol* type,
2851 TRAPS) {
2852 Handle empty;
2853 Handle bsm, info;
2854 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2855 bsm = bootstrap_specifier;
2856 } else {
2857 assert(bootstrap_specifier->is_objArray(), "");
2858 objArrayOop args = (objArrayOop) bootstrap_specifier();
2859 assert(args->length() == 2, "");
2860 bsm = Handle(THREAD, args->obj_at(0));
2861 info = Handle(THREAD, args->obj_at(1));
2862 }
2863 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2864 "caller must supply a valid BSM");
2865
2866 // This should not happen. JDK code should take care of that.
2867 if (caller == NULL) {
2868 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2869 }
2870
2871 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2872
2873 // Resolve the constant type in the context of the caller class
2874 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2875 CHECK_(empty));
2876
2877 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2878 JavaCallArguments args;
2879 args.push_oop(Handle(THREAD, caller->java_mirror()));
2880 args.push_int(condy_index);
2881 args.push_oop(bsm);
2882 args.push_oop(constant_name);
2883 args.push_oop(type_mirror);
2884 args.push_oop(info);
2885 JavaValue result(T_OBJECT);
2886 JavaCalls::call_static(&result,
2887 SystemDictionary::MethodHandleNatives_klass(),
2888 vmSymbols::linkDynamicConstant_name(),
2889 vmSymbols::linkDynamicConstant_signature(),
2890 &args, CHECK_(empty));
2891
2892 return Handle(THREAD, (oop) result.get_jobject());
2893 }
2894
2895 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2896 // name and signature, as interpreted relative to the given class loader.
2897 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2898 int indy_index,
2899 Handle bootstrap_specifier,
2900 Symbol* name,
2901 Symbol* type,
2902 Handle *appendix_result,
2903 Handle *method_type_result,
2904 TRAPS) {
2905 methodHandle empty;
2906 Handle bsm, info;
2907 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2908 bsm = bootstrap_specifier;
2909 } else {
2910 objArrayOop args = (objArrayOop) bootstrap_specifier();
2911 assert(args->length() == 2, "");
2912 bsm = Handle(THREAD, args->obj_at(0));
2913 info = Handle(THREAD, args->obj_at(1));
2914 }
2915 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2916 "caller must supply a valid BSM");
2917
2918 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2919 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2920
2921 // This should not happen. JDK code should take care of that.
2922 if (caller == NULL || method_type.is_null()) {
2923 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2924 }
2925
2926 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2927 assert(appendix_box->obj_at(0) == NULL, "");
2928
2929 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2930 JavaCallArguments args;
2931 args.push_oop(Handle(THREAD, caller->java_mirror()));
2932 args.push_int(indy_index);
2933 args.push_oop(bsm);
2934 args.push_oop(method_name);
2935 args.push_oop(method_type);
2936 args.push_oop(info);
2937 args.push_oop(appendix_box);
2938 JavaValue result(T_OBJECT);
2939 JavaCalls::call_static(&result,
2940 SystemDictionary::MethodHandleNatives_klass(),
2941 vmSymbols::linkCallSite_name(),
2942 vmSymbols::linkCallSite_signature(),
2943 &args, CHECK_(empty));
2944 Handle mname(THREAD, (oop) result.get_jobject());
2945 (*method_type_result) = method_type;
2946 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2947 }
2948
2949 // Protection domain cache table handling
2950
2951 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2952 return _pd_cache_table->get(protection_domain);
2953 }
2954
2955 #if INCLUDE_CDS
2956 void SystemDictionary::reorder_dictionary_for_sharing() {
2957 ClassLoaderData::the_null_class_loader_data()->dictionary()->reorder_dictionary_for_sharing();
2958 }
2959 #endif
2960
2961 size_t SystemDictionary::count_bytes_for_buckets() {
2962 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_buckets();
2963 }
2964
2965 size_t SystemDictionary::count_bytes_for_table() {
2966 return ClassLoaderData::the_null_class_loader_data()->dictionary()->count_bytes_for_table();
2967 }
2968
2969 void SystemDictionary::copy_buckets(char* top, char* end) {
2970 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_buckets(top, end);
2971 }
2972
2973 void SystemDictionary::copy_table(char* top, char* end) {
2974 ClassLoaderData::the_null_class_loader_data()->dictionary()->copy_table(top, end);
2975 }
2976
2977 // ----------------------------------------------------------------------------
2978 void SystemDictionary::print_shared(outputStream *st) {
2979 shared_dictionary()->print_on(st);
2980 }
2981
2982 void SystemDictionary::print_on(outputStream *st) {
2983 if (shared_dictionary() != NULL) {
2984 st->print_cr("Shared Dictionary");
2985 shared_dictionary()->print_on(st);
2986 st->cr();
2987 }
2988
2989 GCMutexLocker mu(SystemDictionary_lock);
2990
2991 ClassLoaderDataGraph::print_dictionary(st);
2992
2993 // Placeholders
2994 placeholders()->print_on(st);
2995 st->cr();
2996
2997 // loader constraints - print under SD_lock
2998 constraints()->print_on(st);
2999 st->cr();
3000
3001 _pd_cache_table->print_on(st);
3002 st->cr();
3003 }
3004
3005 void SystemDictionary::verify() {
3006 guarantee(constraints() != NULL,
3007 "Verify of loader constraints failed");
3008 guarantee(placeholders()->number_of_entries() >= 0,
3009 "Verify of placeholders failed");
3010
3011 GCMutexLocker mu(SystemDictionary_lock);
3012
3013 // Verify dictionary
3014 ClassLoaderDataGraph::verify_dictionary();
3015
3016 placeholders()->verify();
3017
3018 // Verify constraint table
3019 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3020 constraints()->verify(placeholders());
3021
3022 _pd_cache_table->verify();
3023 }
3024
3025 void SystemDictionary::dump(outputStream *st, bool verbose) {
3026 assert_locked_or_safepoint(SystemDictionary_lock);
3027 if (verbose) {
3028 print_on(st);
3029 } else {
3030 if (shared_dictionary() != NULL) {
3031 shared_dictionary()->print_table_statistics(st, "Shared Dictionary");
3032 }
3033 ClassLoaderDataGraph::print_dictionary_statistics(st);
3034 placeholders()->print_table_statistics(st, "Placeholder Table");
3035 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3036 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
3037 }
3038 }
3039
3040 // Utility for dumping dictionaries.
3041 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3042 DCmdWithParser(output, heap),
3043 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3044 "BOOLEAN", false, "false") {
3045 _dcmdparser.add_dcmd_option(&_verbose);
3046 }
3047
3048 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3049 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3050 _verbose.value());
3051 VMThread::execute(&dumper);
3052 }
3053
3054 int SystemDictionaryDCmd::num_arguments() {
3055 ResourceMark rm;
3056 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3057 if (dcmd != NULL) {
3058 DCmdMark mark(dcmd);
3059 return dcmd->_dcmdparser.num_arguments();
3060 } else {
3061 return 0;
3062 }
3063 }
3064
3065 class CombineDictionariesClosure : public CLDClosure {
3066 private:
3067 Dictionary* _master_dictionary;
3068 public:
3069 CombineDictionariesClosure(Dictionary* master_dictionary) :
3070 _master_dictionary(master_dictionary) {}
3071 void do_cld(ClassLoaderData* cld) {
3072 ResourceMark rm;
3073 if (cld->is_anonymous()) {
3074 return;
3075 }
3076 if (cld->is_system_class_loader_data() || cld->is_platform_class_loader_data()) {
3077 for (int i = 0; i < cld->dictionary()->table_size(); ++i) {
3078 Dictionary* curr_dictionary = cld->dictionary();
3079 DictionaryEntry* p = curr_dictionary->bucket(i);
3080 while (p != NULL) {
3081 Symbol* name = p->instance_klass()->name();
3082 unsigned int d_hash = _master_dictionary->compute_hash(name);
3083 int d_index = _master_dictionary->hash_to_index(d_hash);
3084 DictionaryEntry* next = p->next();
3085 if (p->literal()->class_loader_data() != cld) {
3086 // This is an initiating class loader entry; don't use it
3087 log_trace(cds)("Skipping initiating cl entry: %s", name->as_C_string());
3088 curr_dictionary->free_entry(p);
3089 } else {
3090 log_trace(cds)("Moved to boot dictionary: %s", name->as_C_string());
3091 curr_dictionary->unlink_entry(p);
3092 p->set_pd_set(NULL); // pd_set is runtime only information and will be reconstructed.
3093 _master_dictionary->add_entry(d_index, p);
3094 }
3095 p = next;
3096 }
3097 *curr_dictionary->bucket_addr(i) = NULL;
3098 }
3099 }
3100 }
3101 };
3102
3103 // Combining platform and system loader dictionaries into boot loader dictionary.
3104 // During run time, we only have one shared dictionary.
3105 void SystemDictionary::combine_shared_dictionaries() {
3106 assert(DumpSharedSpaces, "dump time only");
3107 // If AppCDS isn't enabled, we only dump the classes in the boot loader dictionary
3108 // into the shared archive.
3109 if (UseAppCDS) {
3110 Dictionary* master_dictionary = ClassLoaderData::the_null_class_loader_data()->dictionary();
3111 CombineDictionariesClosure cdc(master_dictionary);
3112 ClassLoaderDataGraph::cld_do(&cdc);
3113 }
3114
3115 // These tables are no longer valid or necessary. Keeping them around will
3116 // cause SystemDictionary::verify() to fail. Let's empty them.
3117 _placeholders = new PlaceholderTable(_placeholder_table_size);
3118 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
3119
3120 NOT_PRODUCT(SystemDictionary::verify());
3121 }
3122
3123 // Caller needs ResourceMark.
3124 const char* SystemDictionary::loader_name(const oop loader) {
3125 return ((loader) == NULL ? "<bootloader>" :
3126 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
3127 }
3128
3129 // caller needs ResourceMark
3130 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
3131 return (loader_data->class_loader() == NULL ? "<bootloader>" :
3132 SystemDictionary::loader_name(loader_data->class_loader()));
3133 }
3134
3135 void SystemDictionary::initialize_oop_storage() {
3136 _vm_weak_oop_storage =
3137 new OopStorage("VM Weak Oop Handles",
3138 VMWeakAlloc_lock,
3139 VMWeakActive_lock);
3140 }
3141
3142 OopStorage* SystemDictionary::vm_weak_oop_storage() {
3143 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
3144 return _vm_weak_oop_storage;
3145 }