1 /*
2 * Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "aot/aotLoader.hpp"
27 #include "classfile/classFileParser.hpp"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/classLoaderData.inline.hpp"
31 #include "classfile/classLoaderExt.hpp"
32 #include "classfile/dictionary.hpp"
33 #include "classfile/javaClasses.inline.hpp"
34 #include "classfile/klassFactory.hpp"
35 #include "classfile/loaderConstraints.hpp"
36 #include "classfile/packageEntry.hpp"
37 #include "classfile/placeholders.hpp"
38 #include "classfile/resolutionErrors.hpp"
39 #include "classfile/stringTable.hpp"
40 #include "classfile/systemDictionary.hpp"
41 #include "classfile/vmSymbols.hpp"
42 #include "code/codeCache.hpp"
43 #include "compiler/compileBroker.hpp"
44 #include "gc/shared/gcLocker.hpp"
45 #include "gc/shared/gcTraceTime.inline.hpp"
46 #include "interpreter/bytecodeStream.hpp"
47 #include "interpreter/interpreter.hpp"
48 #include "logging/log.hpp"
49 #include "logging/logStream.hpp"
50 #include "memory/filemap.hpp"
51 #include "memory/oopFactory.hpp"
52 #include "memory/resourceArea.hpp"
53 #include "oops/instanceKlass.hpp"
54 #include "oops/instanceRefKlass.hpp"
55 #include "oops/klass.inline.hpp"
56 #include "oops/methodData.hpp"
57 #include "oops/objArrayKlass.hpp"
58 #include "oops/objArrayOop.inline.hpp"
59 #include "oops/oop.inline.hpp"
60 #include "oops/symbol.hpp"
61 #include "oops/typeArrayKlass.hpp"
62 #include "prims/jvm.h"
63 #include "prims/jvmtiEnvBase.hpp"
64 #include "prims/resolvedMethodTable.hpp"
65 #include "prims/methodHandles.hpp"
66 #include "runtime/arguments.hpp"
67 #include "runtime/biasedLocking.hpp"
68 #include "runtime/fieldType.hpp"
69 #include "runtime/handles.inline.hpp"
70 #include "runtime/java.hpp"
71 #include "runtime/javaCalls.hpp"
72 #include "runtime/mutexLocker.hpp"
73 #include "runtime/orderAccess.inline.hpp"
74 #include "runtime/signature.hpp"
75 #include "services/classLoadingService.hpp"
76 #include "services/threadService.hpp"
77 #include "trace/traceMacros.hpp"
78 #include "utilities/macros.hpp"
79 #include "utilities/ticks.hpp"
80 #if INCLUDE_CDS
81 #include "classfile/sharedClassUtil.hpp"
82 #include "classfile/systemDictionaryShared.hpp"
83 #endif
84 #if INCLUDE_JVMCI
85 #include "jvmci/jvmciRuntime.hpp"
86 #endif
87 #if INCLUDE_TRACE
88 #include "trace/tracing.hpp"
89 #endif
90
91 Dictionary* SystemDictionary::_dictionary = NULL;
92 PlaceholderTable* SystemDictionary::_placeholders = NULL;
93 Dictionary* SystemDictionary::_shared_dictionary = NULL;
94 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
95 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
96 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
97
98
99 int SystemDictionary::_number_of_modifications = 0;
100 int SystemDictionary::_sdgeneration = 0;
101 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
102 20201,40423,99991};
103
104 oop SystemDictionary::_system_loader_lock_obj = NULL;
105
106 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
107 = { NULL /*, NULL...*/ };
108
109 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
110
111 oop SystemDictionary::_java_system_loader = NULL;
112
113 bool SystemDictionary::_has_loadClassInternal = false;
114 bool SystemDictionary::_has_checkPackageAccess = false;
115
116 // lazily initialized klass variables
117 InstanceKlass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
118
119
120 // ----------------------------------------------------------------------------
121 // Java-level SystemLoader
122
123 oop SystemDictionary::java_system_loader() {
124 return _java_system_loader;
125 }
126
127 void SystemDictionary::compute_java_system_loader(TRAPS) {
128 Klass* system_klass = WK_KLASS(ClassLoader_klass);
129 JavaValue result(T_OBJECT);
130 JavaCalls::call_static(&result,
131 WK_KLASS(ClassLoader_klass),
132 vmSymbols::getSystemClassLoader_name(),
133 vmSymbols::void_classloader_signature(),
134 CHECK);
135
136 _java_system_loader = (oop)result.get_jobject();
137
138 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
139 }
140
141
142 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
143 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
144 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
145 }
146
147 // ----------------------------------------------------------------------------
148 // Parallel class loading check
149
150 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
151 if (UnsyncloadClass || class_loader.is_null()) return true;
152 if (AlwaysLockClassLoader) return false;
153 return java_lang_ClassLoader::parallelCapable(class_loader());
154 }
155 // ----------------------------------------------------------------------------
156 // ParallelDefineClass flag does not apply to bootclass loader
157 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
158 if (class_loader.is_null()) return false;
159 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
160 return true;
161 }
162 return false;
163 }
164
165 // Returns true if the passed class loader is the builtin application class loader
166 // or a custom system class loader. A customer system class loader can be
167 // specified via -Djava.system.class.loader.
168 bool SystemDictionary::is_system_class_loader(oop class_loader) {
169 if (class_loader == NULL) {
170 return false;
171 }
172 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
173 class_loader == _java_system_loader);
174 }
175
176 // Returns true if the passed class loader is the platform class loader.
177 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
178 if (class_loader == NULL) {
179 return false;
180 }
181 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
182 }
183
184 // ----------------------------------------------------------------------------
185 // Resolving of classes
186
187 // Forwards to resolve_or_null
188
189 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
190 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
191 if (HAS_PENDING_EXCEPTION || klass == NULL) {
192 // can return a null klass
193 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
194 }
195 return klass;
196 }
197
198 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
199 bool throw_error,
200 Klass* klass, TRAPS) {
201 if (HAS_PENDING_EXCEPTION) {
202 // If we have a pending exception we forward it to the caller, unless throw_error is true,
203 // in which case we have to check whether the pending exception is a ClassNotFoundException,
204 // and if so convert it to a NoClassDefFoundError
205 // And chain the original ClassNotFoundException
206 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
207 ResourceMark rm(THREAD);
208 assert(klass == NULL, "Should not have result with exception pending");
209 Handle e(THREAD, PENDING_EXCEPTION);
210 CLEAR_PENDING_EXCEPTION;
211 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
212 } else {
213 return NULL;
214 }
215 }
216 // Class not found, throw appropriate error or exception depending on value of throw_error
217 if (klass == NULL) {
218 ResourceMark rm(THREAD);
219 if (throw_error) {
220 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
221 } else {
222 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
223 }
224 }
225 return klass;
226 }
227
228
229 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
230 bool throw_error, TRAPS)
231 {
232 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
233 }
234
235
236 // Forwards to resolve_instance_class_or_null
237
238 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
239 assert(THREAD->can_call_java(),
240 "can not load classes with compiler thread: class=%s, classloader=%s",
241 class_name->as_C_string(),
242 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
243 if (FieldType::is_array(class_name)) {
244 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
245 } else if (FieldType::is_obj(class_name)) {
246 ResourceMark rm(THREAD);
247 // Ignore wrapping L and ;.
248 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
249 class_name->utf8_length() - 2, CHECK_NULL);
250 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
251 } else {
252 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
253 }
254 }
255
256 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
257 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
258 }
259
260 // Forwards to resolve_instance_class_or_null
261
262 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
263 Handle class_loader,
264 Handle protection_domain,
265 TRAPS) {
266 assert(FieldType::is_array(class_name), "must be array");
267 Klass* k = NULL;
268 FieldArrayInfo fd;
269 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
270 // of this call
271 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
272 if (t == T_OBJECT) {
273 // naked oop "k" is OK here -- we assign back into it
274 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
275 class_loader,
276 protection_domain,
277 CHECK_NULL);
278 if (k != NULL) {
279 k = k->array_klass(fd.dimension(), CHECK_NULL);
280 }
281 } else {
282 k = Universe::typeArrayKlassObj(t);
283 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
284 }
285 return k;
286 }
287
288
289 // Must be called for any super-class or super-interface resolution
290 // during class definition to allow class circularity checking
291 // super-interface callers:
292 // parse_interfaces - for defineClass & jvmtiRedefineClasses
293 // super-class callers:
294 // ClassFileParser - for defineClass & jvmtiRedefineClasses
295 // load_shared_class - while loading a class from shared archive
296 // resolve_instance_class_or_null:
297 // via: handle_parallel_super_load
298 // when resolving a class that has an existing placeholder with
299 // a saved superclass [i.e. a defineClass is currently in progress]
300 // if another thread is trying to resolve the class, it must do
301 // super-class checks on its own thread to catch class circularity
302 // This last call is critical in class circularity checking for cases
303 // where classloading is delegated to different threads and the
304 // classloader lock is released.
305 // Take the case: Base->Super->Base
306 // 1. If thread T1 tries to do a defineClass of class Base
307 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
308 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
309 // so it tries to load Super
310 // 3. If we load the class internally, or user classloader uses same thread
311 // loadClassFromxxx or defineClass via parseClassFile Super ...
312 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
313 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
314 // 3.4 calls resolve_super_or_fail Base
315 // 3.5 finds T1,Base -> throws class circularity
316 //OR 4. If T2 tries to resolve Super via defineClass Super ...
317 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
318 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
319 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
320 // 4.4 finds T2, Super -> throws class circularity
321 // Must be called, even if superclass is null, since this is
322 // where the placeholder entry is created which claims this
323 // thread is loading this class/classloader.
324 // Be careful when modifying this code: once you have run
325 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
326 // you need to find_and_remove it before returning.
327 // So be careful to not exit with a CHECK_ macro betweeen these calls.
328 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
329 Symbol* class_name,
330 Handle class_loader,
331 Handle protection_domain,
332 bool is_superclass,
333 TRAPS) {
334 #if INCLUDE_CDS
335 if (DumpSharedSpaces) {
336 // Special processing for CDS dump time.
337 Klass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
338 class_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
339 if (k) {
340 return k;
341 }
342 }
343 #endif // INCLUDE_CDS
344
345 // Double-check, if child class is already loaded, just return super-class,interface
346 // Don't add a placedholder if already loaded, i.e. already in system dictionary
347 // Make sure there's a placeholder for the *child* before resolving.
348 // Used as a claim that this thread is currently loading superclass/classloader
349 // Used here for ClassCircularity checks and also for heap verification
350 // (every InstanceKlass in the heap needs to be in the system dictionary
351 // or have a placeholder).
352 // Must check ClassCircularity before checking if super class is already loaded
353 //
354 // We might not already have a placeholder if this child_name was
355 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
356 // the name of the class might not be known until the stream is actually
357 // parsed.
358 // Bugs 4643874, 4715493
359 // compute_hash can have a safepoint
360
361 ClassLoaderData* loader_data = class_loader_data(class_loader);
362 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
363 int d_index = dictionary()->hash_to_index(d_hash);
364 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
365 int p_index = placeholders()->hash_to_index(p_hash);
366 // can't throw error holding a lock
367 bool child_already_loaded = false;
368 bool throw_circularity_error = false;
369 {
370 MutexLocker mu(SystemDictionary_lock, THREAD);
371 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
372 Klass* quicksuperk;
373 // to support // loading: if child done loading, just return superclass
374 // if class_name, & class_loader don't match:
375 // if initial define, SD update will give LinkageError
376 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
377 // so we don't throw an exception here.
378 // see: nsk redefclass014 & java.lang.instrument Instrument032
379 if ((childk != NULL ) && (is_superclass) &&
380 ((quicksuperk = childk->super()) != NULL) &&
381
382 ((quicksuperk->name() == class_name) &&
383 (quicksuperk->class_loader() == class_loader()))) {
384 return quicksuperk;
385 } else {
386 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
387 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
388 throw_circularity_error = true;
389 }
390 }
391 if (!throw_circularity_error) {
392 // Be careful not to exit resolve_super
393 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
394 }
395 }
396 if (throw_circularity_error) {
397 ResourceMark rm(THREAD);
398 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
399 }
400
401 // java.lang.Object should have been found above
402 assert(class_name != NULL, "null super class for resolving");
403 // Resolve the super class or interface, check results on return
404 Klass* superk = SystemDictionary::resolve_or_null(class_name,
405 class_loader,
406 protection_domain,
407 THREAD);
408
409 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
410 // It is no longer necessary to keep the placeholder table alive until update_dictionary
411 // or error. GC used to walk the placeholder table as strong roots.
412 // The instanceKlass is kept alive because the class loader is on the stack,
413 // which keeps the loader_data alive, as well as all instanceKlasses in
414 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
415 {
416 MutexLocker mu(SystemDictionary_lock, THREAD);
417 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
418 SystemDictionary_lock->notify_all();
419 }
420 if (HAS_PENDING_EXCEPTION || superk == NULL) {
421 // can null superk
422 superk = handle_resolution_exception(class_name, true, superk, THREAD);
423 }
424
425 return superk;
426 }
427
428 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
429 Handle class_loader,
430 Handle protection_domain,
431 TRAPS) {
432 if(!has_checkPackageAccess()) return;
433
434 // Now we have to call back to java to check if the initating class has access
435 JavaValue result(T_VOID);
436 LogTarget(Debug, protectiondomain) lt;
437 if (lt.is_enabled()) {
438 ResourceMark rm;
439 // Print out trace information
440 LogStream ls(lt);
441 ls.print_cr("Checking package access");
442 ls.print("class loader: "); class_loader()->print_value_on(&ls);
443 ls.print(" protection domain: "); protection_domain()->print_value_on(&ls);
444 ls.print(" loading: "); klass->print_value_on(&ls);
445 ls.cr();
446 }
447
448 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
449 JavaCalls::call_special(&result,
450 class_loader,
451 system_loader,
452 vmSymbols::checkPackageAccess_name(),
453 vmSymbols::class_protectiondomain_signature(),
454 Handle(THREAD, klass->java_mirror()),
455 protection_domain,
456 THREAD);
457
458 if (HAS_PENDING_EXCEPTION) {
459 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
460 } else {
461 log_debug(protectiondomain)("granted");
462 }
463
464 if (HAS_PENDING_EXCEPTION) return;
465
466 // If no exception has been thrown, we have validated the protection domain
467 // Insert the protection domain of the initiating class into the set.
468 {
469 // We recalculate the entry here -- we've called out to java since
470 // the last time it was calculated.
471 ClassLoaderData* loader_data = class_loader_data(class_loader);
472
473 Symbol* kn = klass->name();
474 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
475 int d_index = dictionary()->hash_to_index(d_hash);
476
477 MutexLocker mu(SystemDictionary_lock, THREAD);
478 {
479 // Note that we have an entry, and entries can be deleted only during GC,
480 // so we cannot allow GC to occur while we're holding this entry.
481
482 // We're using a NoSafepointVerifier to catch any place where we
483 // might potentially do a GC at all.
484 // Dictionary::do_unloading() asserts that classes in SD are only
485 // unloaded at a safepoint. Anonymous classes are not in SD.
486 NoSafepointVerifier nosafepoint;
487 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
488 protection_domain, THREAD);
489 }
490 }
491 }
492
493 // We only get here if this thread finds that another thread
494 // has already claimed the placeholder token for the current operation,
495 // but that other thread either never owned or gave up the
496 // object lock
497 // Waits on SystemDictionary_lock to indicate placeholder table updated
498 // On return, caller must recheck placeholder table state
499 //
500 // We only get here if
501 // 1) custom classLoader, i.e. not bootstrap classloader
502 // 2) UnsyncloadClass not set
503 // 3) custom classLoader has broken the class loader objectLock
504 // so another thread got here in parallel
505 //
506 // lockObject must be held.
507 // Complicated dance due to lock ordering:
508 // Must first release the classloader object lock to
509 // allow initial definer to complete the class definition
510 // and to avoid deadlock
511 // Reclaim classloader lock object with same original recursion count
512 // Must release SystemDictionary_lock after notify, since
513 // class loader lock must be claimed before SystemDictionary_lock
514 // to prevent deadlocks
515 //
516 // The notify allows applications that did an untimed wait() on
517 // the classloader object lock to not hang.
518 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
519 assert_lock_strong(SystemDictionary_lock);
520
521 bool calledholdinglock
522 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
523 assert(calledholdinglock,"must hold lock for notify");
524 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
525 ObjectSynchronizer::notifyall(lockObject, THREAD);
526 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
527 SystemDictionary_lock->wait();
528 SystemDictionary_lock->unlock();
529 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
530 SystemDictionary_lock->lock();
531 }
532
533 // If the class in is in the placeholder table, class loading is in progress
534 // For cases where the application changes threads to load classes, it
535 // is critical to ClassCircularity detection that we try loading
536 // the superclass on the same thread internally, so we do parallel
537 // super class loading here.
538 // This also is critical in cases where the original thread gets stalled
539 // even in non-circularity situations.
540 // Note: must call resolve_super_or_fail even if null super -
541 // to force placeholder entry creation for this class for circularity detection
542 // Caller must check for pending exception
543 // Returns non-null Klass* if other thread has completed load
544 // and we are done,
545 // If return null Klass* and no pending exception, the caller must load the class
546 InstanceKlass* SystemDictionary::handle_parallel_super_load(
547 Symbol* name, Symbol* superclassname, Handle class_loader,
548 Handle protection_domain, Handle lockObject, TRAPS) {
549
550 ClassLoaderData* loader_data = class_loader_data(class_loader);
551 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
552 int d_index = dictionary()->hash_to_index(d_hash);
553 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
554 int p_index = placeholders()->hash_to_index(p_hash);
555
556 // superk is not used, resolve_super called for circularity check only
557 // This code is reached in two situations. One if this thread
558 // is loading the same class twice (e.g. ClassCircularity, or
559 // java.lang.instrument).
560 // The second is if another thread started the resolve_super first
561 // and has not yet finished.
562 // In both cases the original caller will clean up the placeholder
563 // entry on error.
564 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
565 superclassname,
566 class_loader,
567 protection_domain,
568 true,
569 CHECK_NULL);
570
571 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
572 // Serial class loaders and bootstrap classloader do wait for superclass loads
573 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
574 MutexLocker mu(SystemDictionary_lock, THREAD);
575 // Check if classloading completed while we were loading superclass or waiting
576 return find_class(d_index, d_hash, name, loader_data);
577 }
578
579 // must loop to both handle other placeholder updates
580 // and spurious notifications
581 bool super_load_in_progress = true;
582 PlaceholderEntry* placeholder;
583 while (super_load_in_progress) {
584 MutexLocker mu(SystemDictionary_lock, THREAD);
585 // Check if classloading completed while we were loading superclass or waiting
586 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
587 if (check != NULL) {
588 // Klass is already loaded, so just return it
589 return check;
590 } else {
591 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
592 if (placeholder && placeholder->super_load_in_progress() ){
593 // Before UnsyncloadClass:
594 // We only get here if the application has released the
595 // classloader lock when another thread was in the middle of loading a
596 // superclass/superinterface for this class, and now
597 // this thread is also trying to load this class.
598 // To minimize surprises, the first thread that started to
599 // load a class should be the one to complete the loading
600 // with the classfile it initially expected.
601 // This logic has the current thread wait once it has done
602 // all the superclass/superinterface loading it can, until
603 // the original thread completes the class loading or fails
604 // If it completes we will use the resulting InstanceKlass
605 // which we will find below in the systemDictionary.
606 // We also get here for parallel bootstrap classloader
607 if (class_loader.is_null()) {
608 SystemDictionary_lock->wait();
609 } else {
610 double_lock_wait(lockObject, THREAD);
611 }
612 } else {
613 // If not in SD and not in PH, other thread's load must have failed
614 super_load_in_progress = false;
615 }
616 }
617 }
618 return NULL;
619 }
620
621 static void post_class_load_event(const Ticks& start_time,
622 InstanceKlass* k,
623 const ClassLoaderData* init_cld) {
624 #if INCLUDE_TRACE
625 EventClassLoad event(UNTIMED);
626 if (event.should_commit()) {
627 event.set_starttime(start_time);
628 event.set_loadedClass(k);
629 event.set_definingClassLoader(k->class_loader_data());
630 event.set_initiatingClassLoader(init_cld);
631 event.commit();
632 }
633 #endif // INCLUDE_TRACE
634 }
635
636 static void class_define_event(InstanceKlass* k,
637 const ClassLoaderData* def_cld) {
638 #if INCLUDE_TRACE
639 EventClassDefine event;
640 if (event.should_commit()) {
641 event.set_definedClass(k);
642 event.set_definingClassLoader(def_cld);
643 event.commit();
644 }
645 #endif // INCLUDE_TRACE
646 }
647
648 // Be careful when modifying this code: once you have run
649 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
650 // you need to find_and_remove it before returning.
651 // So be careful to not exit with a CHECK_ macro betweeen these calls.
652 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
653 Handle class_loader,
654 Handle protection_domain,
655 TRAPS) {
656 assert(name != NULL && !FieldType::is_array(name) &&
657 !FieldType::is_obj(name), "invalid class name");
658
659 Ticks class_load_start_time = Ticks::now();
660
661 HandleMark hm(THREAD);
662
663 // Fix for 4474172; see evaluation for more details
664 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
665 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
666
667 // Do lookup to see if class already exist and the protection domain
668 // has the right access
669 // This call uses find which checks protection domain already matches
670 // All subsequent calls use find_class, and set has_loaded_class so that
671 // before we return a result we call out to java to check for valid protection domain
672 // to allow returning the Klass* and add it to the pd_set if it is valid
673 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
674 int d_index = dictionary()->hash_to_index(d_hash);
675 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
676 protection_domain, THREAD);
677 if (probe != NULL) return probe;
678
679
680 // Non-bootstrap class loaders will call out to class loader and
681 // define via jvm/jni_DefineClass which will acquire the
682 // class loader object lock to protect against multiple threads
683 // defining the class in parallel by accident.
684 // This lock must be acquired here so the waiter will find
685 // any successful result in the SystemDictionary and not attempt
686 // the define
687 // ParallelCapable Classloaders and the bootstrap classloader,
688 // or all classloaders with UnsyncloadClass do not acquire lock here
689 bool DoObjectLock = true;
690 if (is_parallelCapable(class_loader)) {
691 DoObjectLock = false;
692 }
693
694 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
695 int p_index = placeholders()->hash_to_index(p_hash);
696
697 // Class is not in SystemDictionary so we have to do loading.
698 // Make sure we are synchronized on the class loader before we proceed
699 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
700 check_loader_lock_contention(lockObject, THREAD);
701 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
702
703 // Check again (after locking) if class already exist in SystemDictionary
704 bool class_has_been_loaded = false;
705 bool super_load_in_progress = false;
706 bool havesupername = false;
707 InstanceKlass* k = NULL;
708 PlaceholderEntry* placeholder;
709 Symbol* superclassname = NULL;
710
711 {
712 MutexLocker mu(SystemDictionary_lock, THREAD);
713 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
714 if (check != NULL) {
715 // Klass is already loaded, so just return it
716 class_has_been_loaded = true;
717 k = check;
718 } else {
719 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
720 if (placeholder && placeholder->super_load_in_progress()) {
721 super_load_in_progress = true;
722 if (placeholder->havesupername() == true) {
723 superclassname = placeholder->supername();
724 havesupername = true;
725 }
726 }
727 }
728 }
729
730 // If the class is in the placeholder table, class loading is in progress
731 if (super_load_in_progress && havesupername==true) {
732 k = handle_parallel_super_load(name,
733 superclassname,
734 class_loader,
735 protection_domain,
736 lockObject, THREAD);
737 if (HAS_PENDING_EXCEPTION) {
738 return NULL;
739 }
740 if (k != NULL) {
741 class_has_been_loaded = true;
742 }
743 }
744
745 bool throw_circularity_error = false;
746 if (!class_has_been_loaded) {
747 bool load_instance_added = false;
748
749 // add placeholder entry to record loading instance class
750 // Five cases:
751 // All cases need to prevent modifying bootclasssearchpath
752 // in parallel with a classload of same classname
753 // Redefineclasses uses existence of the placeholder for the duration
754 // of the class load to prevent concurrent redefinition of not completely
755 // defined classes.
756 // case 1. traditional classloaders that rely on the classloader object lock
757 // - no other need for LOAD_INSTANCE
758 // case 2. traditional classloaders that break the classloader object lock
759 // as a deadlock workaround. Detection of this case requires that
760 // this check is done while holding the classloader object lock,
761 // and that lock is still held when calling classloader's loadClass.
762 // For these classloaders, we ensure that the first requestor
763 // completes the load and other requestors wait for completion.
764 // case 3. UnsyncloadClass - don't use objectLocker
765 // With this flag, we allow parallel classloading of a
766 // class/classloader pair
767 // case4. Bootstrap classloader - don't own objectLocker
768 // This classloader supports parallelism at the classloader level,
769 // but only allows a single load of a class/classloader pair.
770 // No performance benefit and no deadlock issues.
771 // case 5. parallelCapable user level classloaders - without objectLocker
772 // Allow parallel classloading of a class/classloader pair
773
774 {
775 MutexLocker mu(SystemDictionary_lock, THREAD);
776 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
777 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
778 if (oldprobe) {
779 // only need check_seen_thread once, not on each loop
780 // 6341374 java/lang/Instrument with -Xcomp
781 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
782 throw_circularity_error = true;
783 } else {
784 // case 1: traditional: should never see load_in_progress.
785 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
786
787 // case 4: bootstrap classloader: prevent futile classloading,
788 // wait on first requestor
789 if (class_loader.is_null()) {
790 SystemDictionary_lock->wait();
791 } else {
792 // case 2: traditional with broken classloader lock. wait on first
793 // requestor.
794 double_lock_wait(lockObject, THREAD);
795 }
796 // Check if classloading completed while we were waiting
797 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
798 if (check != NULL) {
799 // Klass is already loaded, so just return it
800 k = check;
801 class_has_been_loaded = true;
802 }
803 // check if other thread failed to load and cleaned up
804 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
805 }
806 }
807 }
808 }
809 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
810 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
811 // LOAD_INSTANCE in parallel
812
813 if (!throw_circularity_error && !class_has_been_loaded) {
814 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
815 load_instance_added = true;
816 // For class loaders that do not acquire the classloader object lock,
817 // if they did not catch another thread holding LOAD_INSTANCE,
818 // need a check analogous to the acquire ObjectLocker/find_class
819 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
820 // one final check if the load has already completed
821 // class loaders holding the ObjectLock shouldn't find the class here
822 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
823 if (check != NULL) {
824 // Klass is already loaded, so return it after checking/adding protection domain
825 k = check;
826 class_has_been_loaded = true;
827 }
828 }
829 }
830
831 // must throw error outside of owning lock
832 if (throw_circularity_error) {
833 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
834 ResourceMark rm(THREAD);
835 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
836 }
837
838 if (!class_has_been_loaded) {
839
840 // Do actual loading
841 k = load_instance_class(name, class_loader, THREAD);
842
843 // For UnsyncloadClass only
844 // If they got a linkageError, check if a parallel class load succeeded.
845 // If it did, then for bytecode resolution the specification requires
846 // that we return the same result we did for the other thread, i.e. the
847 // successfully loaded InstanceKlass
848 // Should not get here for classloaders that support parallelism
849 // with the new cleaner mechanism, even with AllowParallelDefineClass
850 // Bootstrap goes through here to allow for an extra guarantee check
851 if (UnsyncloadClass || (class_loader.is_null())) {
852 if (k == NULL && HAS_PENDING_EXCEPTION
853 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
854 MutexLocker mu(SystemDictionary_lock, THREAD);
855 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
856 if (check != NULL) {
857 // Klass is already loaded, so just use it
858 k = check;
859 CLEAR_PENDING_EXCEPTION;
860 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
861 }
862 }
863 }
864
865 // If everything was OK (no exceptions, no null return value), and
866 // class_loader is NOT the defining loader, do a little more bookkeeping.
867 if (!HAS_PENDING_EXCEPTION && k != NULL &&
868 k->class_loader() != class_loader()) {
869
870 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
871
872 // Need to check for a PENDING_EXCEPTION again; check_constraints
873 // can throw and doesn't use the CHECK macro.
874 if (!HAS_PENDING_EXCEPTION) {
875 { // Grabbing the Compile_lock prevents systemDictionary updates
876 // during compilations.
877 MutexLocker mu(Compile_lock, THREAD);
878 update_dictionary(d_index, d_hash, p_index, p_hash,
879 k, class_loader, THREAD);
880 }
881
882 if (JvmtiExport::should_post_class_load()) {
883 Thread *thread = THREAD;
884 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
885 JvmtiExport::post_class_load((JavaThread *) thread, k);
886 }
887 }
888 }
889 } // load_instance_class loop
890
891 if (load_instance_added == true) {
892 // clean up placeholder entries for LOAD_INSTANCE success or error
893 // This brackets the SystemDictionary updates for both defining
894 // and initiating loaders
895 MutexLocker mu(SystemDictionary_lock, THREAD);
896 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
897 SystemDictionary_lock->notify_all();
898 }
899 }
900
901 if (HAS_PENDING_EXCEPTION || k == NULL) {
902 return NULL;
903 }
904
905 post_class_load_event(class_load_start_time, k, loader_data);
906
907 #ifdef ASSERT
908 {
909 ClassLoaderData* loader_data = k->class_loader_data();
910 MutexLocker mu(SystemDictionary_lock, THREAD);
911 Klass* kk = find_class(name, loader_data);
912 assert(kk == k, "should be present in dictionary");
913 }
914 #endif
915
916 // return if the protection domain in NULL
917 if (protection_domain() == NULL) return k;
918
919 // Check the protection domain has the right access
920 {
921 MutexLocker mu(SystemDictionary_lock, THREAD);
922 // Note that we have an entry, and entries can be deleted only during GC,
923 // so we cannot allow GC to occur while we're holding this entry.
924 // We're using a NoSafepointVerifier to catch any place where we
925 // might potentially do a GC at all.
926 // Dictionary::do_unloading() asserts that classes in SD are only
927 // unloaded at a safepoint. Anonymous classes are not in SD.
928 NoSafepointVerifier nosafepoint;
929 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
930 loader_data,
931 protection_domain)) {
932 return k;
933 }
934 }
935
936 // Verify protection domain. If it fails an exception is thrown
937 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
938
939 return k;
940 }
941
942
943 // This routine does not lock the system dictionary.
944 //
945 // Since readers don't hold a lock, we must make sure that system
946 // dictionary entries are only removed at a safepoint (when only one
947 // thread is running), and are added to in a safe way (all links must
948 // be updated in an MT-safe manner).
949 //
950 // Callers should be aware that an entry could be added just after
951 // _dictionary->bucket(index) is read here, so the caller will not see
952 // the new entry.
953
954 Klass* SystemDictionary::find(Symbol* class_name,
955 Handle class_loader,
956 Handle protection_domain,
957 TRAPS) {
958
959 // The result of this call should be consistent with the result
960 // of the call to resolve_instance_class_or_null().
961 // See evaluation 6790209 and 4474172 for more details.
962 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
963 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
964
965 if (loader_data == NULL) {
966 // If the ClassLoaderData has not been setup,
967 // then the class loader has no entries in the dictionary.
968 return NULL;
969 }
970
971 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
972 int d_index = dictionary()->hash_to_index(d_hash);
973
974 {
975 // Note that we have an entry, and entries can be deleted only during GC,
976 // so we cannot allow GC to occur while we're holding this entry.
977 // We're using a NoSafepointVerifier to catch any place where we
978 // might potentially do a GC at all.
979 // Dictionary::do_unloading() asserts that classes in SD are only
980 // unloaded at a safepoint. Anonymous classes are not in SD.
981 NoSafepointVerifier nosafepoint;
982 return dictionary()->find(d_index, d_hash, class_name, loader_data,
983 protection_domain, THREAD);
984 }
985 }
986
987
988 // Look for a loaded instance or array klass by name. Do not do any loading.
989 // return NULL in case of error.
990 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
991 Handle class_loader,
992 Handle protection_domain,
993 TRAPS) {
994 Klass* k = NULL;
995 assert(class_name != NULL, "class name must be non NULL");
996
997 if (FieldType::is_array(class_name)) {
998 // The name refers to an array. Parse the name.
999 // dimension and object_key in FieldArrayInfo are assigned as a
1000 // side-effect of this call
1001 FieldArrayInfo fd;
1002 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1003 if (t != T_OBJECT) {
1004 k = Universe::typeArrayKlassObj(t);
1005 } else {
1006 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1007 }
1008 if (k != NULL) {
1009 k = k->array_klass_or_null(fd.dimension());
1010 }
1011 } else {
1012 k = find(class_name, class_loader, protection_domain, THREAD);
1013 }
1014 return k;
1015 }
1016
1017 // Note: this method is much like resolve_from_stream, but
1018 // does not publish the classes via the SystemDictionary.
1019 // Handles unsafe_DefineAnonymousClass and redefineclasses
1020 // RedefinedClasses do not add to the class hierarchy
1021 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1022 Handle class_loader,
1023 Handle protection_domain,
1024 ClassFileStream* st,
1025 const InstanceKlass* host_klass,
1026 GrowableArray<Handle>* cp_patches,
1027 TRAPS) {
1028
1029 Ticks class_load_start_time = Ticks::now();
1030
1031 ClassLoaderData* loader_data;
1032 if (host_klass != NULL) {
1033 // Create a new CLD for anonymous class, that uses the same class loader
1034 // as the host_klass
1035 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1036 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1037 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1038 loader_data->record_dependency(host_klass, CHECK_NULL);
1039 } else {
1040 loader_data = ClassLoaderData::class_loader_data(class_loader());
1041 }
1042
1043 assert(st != NULL, "invariant");
1044 assert(st->need_verify(), "invariant");
1045
1046 // Parse stream and create a klass.
1047 // Note that we do this even though this klass might
1048 // already be present in the SystemDictionary, otherwise we would not
1049 // throw potential ClassFormatErrors.
1050
1051 InstanceKlass* k = KlassFactory::create_from_stream(st,
1052 class_name,
1053 loader_data,
1054 protection_domain,
1055 host_klass,
1056 cp_patches,
1057 CHECK_NULL);
1058
1059 if (host_klass != NULL && k != NULL) {
1060 // If it's anonymous, initialize it now, since nobody else will.
1061
1062 {
1063 MutexLocker mu_r(Compile_lock, THREAD);
1064
1065 // Add to class hierarchy, initialize vtables, and do possible
1066 // deoptimizations.
1067 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1068
1069 // But, do not add to system dictionary.
1070
1071 // compiled code dependencies need to be validated anyway
1072 notice_modification();
1073 }
1074
1075 // Rewrite and patch constant pool here.
1076 k->link_class(CHECK_NULL);
1077 if (cp_patches != NULL) {
1078 k->constants()->patch_resolved_references(cp_patches);
1079 }
1080 k->eager_initialize(CHECK_NULL);
1081
1082 // notify jvmti
1083 if (JvmtiExport::should_post_class_load()) {
1084 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1085 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1086 }
1087
1088 post_class_load_event(class_load_start_time, k, loader_data);
1089 }
1090 assert(host_klass != NULL || NULL == cp_patches,
1091 "cp_patches only found with host_klass");
1092
1093 return k;
1094 }
1095
1096 // Add a klass to the system from a stream (called by jni_DefineClass and
1097 // JVM_DefineClass).
1098 // Note: class_name can be NULL. In that case we do not know the name of
1099 // the class until we have parsed the stream.
1100
1101 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1102 Handle class_loader,
1103 Handle protection_domain,
1104 ClassFileStream* st,
1105 TRAPS) {
1106
1107 HandleMark hm(THREAD);
1108
1109 // Classloaders that support parallelism, e.g. bootstrap classloader,
1110 // or all classloaders with UnsyncloadClass do not acquire lock here
1111 bool DoObjectLock = true;
1112 if (is_parallelCapable(class_loader)) {
1113 DoObjectLock = false;
1114 }
1115
1116 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1117
1118 // Make sure we are synchronized on the class loader before we proceed
1119 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1120 check_loader_lock_contention(lockObject, THREAD);
1121 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1122
1123 assert(st != NULL, "invariant");
1124
1125 // Parse the stream and create a klass.
1126 // Note that we do this even though this klass might
1127 // already be present in the SystemDictionary, otherwise we would not
1128 // throw potential ClassFormatErrors.
1129 InstanceKlass* k = NULL;
1130
1131 #if INCLUDE_CDS
1132 k = SystemDictionaryShared::lookup_from_stream(class_name,
1133 class_loader,
1134 protection_domain,
1135 st,
1136 CHECK_NULL);
1137 #endif
1138
1139 if (k == NULL) {
1140 if (st->buffer() == NULL) {
1141 return NULL;
1142 }
1143 k = KlassFactory::create_from_stream(st,
1144 class_name,
1145 loader_data,
1146 protection_domain,
1147 NULL, // host_klass
1148 NULL, // cp_patches
1149 CHECK_NULL);
1150 }
1151
1152 assert(k != NULL, "no klass created");
1153 Symbol* h_name = k->name();
1154 assert(class_name == NULL || class_name == h_name, "name mismatch");
1155
1156 // Add class just loaded
1157 // If a class loader supports parallel classloading handle parallel define requests
1158 // find_or_define_instance_class may return a different InstanceKlass
1159 if (is_parallelCapable(class_loader)) {
1160 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1161 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1162 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1163 assert(defined_k != NULL, "Should have a klass if there's no exception");
1164 loader_data->add_to_deallocate_list(k);
1165 k = defined_k;
1166 }
1167 } else {
1168 define_instance_class(k, THREAD);
1169 }
1170
1171 // If defining the class throws an exception register 'k' for cleanup.
1172 if (HAS_PENDING_EXCEPTION) {
1173 assert(k != NULL, "Must have an instance klass here!");
1174 loader_data->add_to_deallocate_list(k);
1175 return NULL;
1176 }
1177
1178 // Make sure we have an entry in the SystemDictionary on success
1179 debug_only( {
1180 MutexLocker mu(SystemDictionary_lock, THREAD);
1181
1182 Klass* check = find_class(h_name, k->class_loader_data());
1183 assert(check == k, "should be present in the dictionary");
1184 } );
1185
1186 return k;
1187 }
1188
1189 #if INCLUDE_CDS
1190 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1191 int number_of_entries) {
1192 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1193 "bad shared dictionary size.");
1194 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1195 }
1196
1197
1198 // If there is a shared dictionary, then find the entry for the
1199 // given shared system class, if any.
1200
1201 InstanceKlass* SystemDictionary::find_shared_class(Symbol* class_name) {
1202 if (shared_dictionary() != NULL) {
1203 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1204 int d_index = shared_dictionary()->hash_to_index(d_hash);
1205
1206 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1207 } else {
1208 return NULL;
1209 }
1210 }
1211
1212
1213 // Load a class from the shared spaces (found through the shared system
1214 // dictionary). Force the superclass and all interfaces to be loaded.
1215 // Update the class definition to include sibling classes and no
1216 // subclasses (yet). [Classes in the shared space are not part of the
1217 // object hierarchy until loaded.]
1218
1219 InstanceKlass* SystemDictionary::load_shared_class(
1220 Symbol* class_name, Handle class_loader, TRAPS) {
1221 InstanceKlass* ik = find_shared_class(class_name);
1222 // Make sure we only return the boot class for the NULL classloader.
1223 if (ik != NULL &&
1224 ik->is_shared_boot_class() && class_loader.is_null()) {
1225 Handle protection_domain;
1226 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1227 }
1228 return NULL;
1229 }
1230
1231 // Check if a shared class can be loaded by the specific classloader:
1232 //
1233 // NULL classloader:
1234 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1235 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1236 // be defined in an unnamed module.
1237 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1238 InstanceKlass* ik,
1239 Handle class_loader, TRAPS) {
1240 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1241 "Cannot use sharing if java.base is patched");
1242 ResourceMark rm;
1243 int path_index = ik->shared_classpath_index();
1244 SharedClassPathEntry* ent =
1245 (SharedClassPathEntry*)FileMapInfo::shared_classpath(path_index);
1246 if (!Universe::is_module_initialized()) {
1247 assert(ent != NULL && ent->is_jrt(),
1248 "Loading non-bootstrap classes before the module system is initialized");
1249 assert(class_loader.is_null(), "sanity");
1250 return true;
1251 }
1252 // Get the pkg_entry from the classloader
1253 TempNewSymbol pkg_name = NULL;
1254 PackageEntry* pkg_entry = NULL;
1255 ModuleEntry* mod_entry = NULL;
1256 const char* pkg_string = NULL;
1257 ClassLoaderData* loader_data = class_loader_data(class_loader);
1258 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1259 if (pkg_name != NULL) {
1260 pkg_string = pkg_name->as_C_string();
1261 if (loader_data != NULL) {
1262 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1263 }
1264 if (pkg_entry != NULL) {
1265 mod_entry = pkg_entry->module();
1266 }
1267 }
1268
1269 // If the archived class is from a module that has been patched at runtime,
1270 // the class cannot be loaded from the archive.
1271 if (mod_entry != NULL && mod_entry->is_patched()) {
1272 return false;
1273 }
1274
1275 if (class_loader.is_null()) {
1276 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1277 // The NULL classloader can load archived class originated from the
1278 // "modules" jimage and the -Xbootclasspath/a. For class from the
1279 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1280 // by the NULL classloader.
1281 if (mod_entry != NULL) {
1282 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1283 // ModuleEntry's location agrees with the archived class' origination.
1284 if (ent->is_jrt() && mod_entry->location()->starts_with("jrt:")) {
1285 return true; // Module class from the "module" jimage
1286 }
1287 }
1288
1289 // If the archived class is not from the "module" jimage, the class can be
1290 // loaded by the NULL classloader if
1291 //
1292 // 1. the class is from the unamed package
1293 // 2. or, the class is not from a module defined in the NULL classloader
1294 // 3. or, the class is from an unamed module
1295 if (!ent->is_jrt() && ik->is_shared_boot_class()) {
1296 // the class is from the -Xbootclasspath/a
1297 if (pkg_string == NULL ||
1298 pkg_entry == NULL ||
1299 pkg_entry->in_unnamed_module()) {
1300 assert(mod_entry == NULL ||
1301 mod_entry == loader_data->unnamed_module(),
1302 "the unnamed module is not defined in the classloader");
1303 return true;
1304 }
1305 }
1306 return false;
1307 } else {
1308 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1309 ik, class_loader, pkg_string, pkg_name,
1310 pkg_entry, mod_entry, CHECK_(false));
1311 return res;
1312 }
1313 }
1314
1315 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1316 Handle class_loader,
1317 Handle protection_domain, TRAPS) {
1318
1319 if (ik != NULL) {
1320 Symbol* class_name = ik->name();
1321
1322 bool visible = is_shared_class_visible(
1323 class_name, ik, class_loader, CHECK_NULL);
1324 if (!visible) {
1325 return NULL;
1326 }
1327
1328 // Resolve the superclass and interfaces. They must be the same
1329 // as in dump time, because the layout of <ik> depends on
1330 // the specific layout of ik->super() and ik->local_interfaces().
1331 //
1332 // If unexpected superclass or interfaces are found, we cannot
1333 // load <ik> from the shared archive.
1334
1335 if (ik->super() != NULL) {
1336 Symbol* cn = ik->super()->name();
1337 Klass *s = resolve_super_or_fail(class_name, cn,
1338 class_loader, protection_domain, true, CHECK_NULL);
1339 if (s != ik->super()) {
1340 // The dynamically resolved super class is not the same as the one we used during dump time,
1341 // so we cannot use ik.
1342 return NULL;
1343 } else {
1344 assert(s->is_shared(), "must be");
1345 }
1346 }
1347
1348 Array<Klass*>* interfaces = ik->local_interfaces();
1349 int num_interfaces = interfaces->length();
1350 for (int index = 0; index < num_interfaces; index++) {
1351 Klass* k = interfaces->at(index);
1352 Symbol* name = k->name();
1353 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1354 if (k != i) {
1355 // The dynamically resolved interface class is not the same as the one we used during dump time,
1356 // so we cannot use ik.
1357 return NULL;
1358 } else {
1359 assert(i->is_shared(), "must be");
1360 }
1361 }
1362
1363 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1364 ik, class_name, class_loader, protection_domain, CHECK_NULL);
1365 if (new_ik != NULL) {
1366 // The class is changed by CFLH. Return the new class. The shared class is
1367 // not used.
1368 return new_ik;
1369 }
1370
1371 // Adjust methods to recover missing data. They need addresses for
1372 // interpreter entry points and their default native method address
1373 // must be reset.
1374
1375 // Updating methods must be done under a lock so multiple
1376 // threads don't update these in parallel
1377 //
1378 // Shared classes are all currently loaded by either the bootstrap or
1379 // internal parallel class loaders, so this will never cause a deadlock
1380 // on a custom class loader lock.
1381
1382 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1383 {
1384 HandleMark hm(THREAD);
1385 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1386 check_loader_lock_contention(lockObject, THREAD);
1387 ObjectLocker ol(lockObject, THREAD, true);
1388 // prohibited package check assumes all classes loaded from archive call
1389 // restore_unshareable_info which calls ik->set_package()
1390 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1391 }
1392
1393 ik->print_class_load_logging(loader_data, NULL, NULL);
1394
1395 // For boot loader, ensure that GetSystemPackage knows that a class in this
1396 // package was loaded.
1397 if (class_loader.is_null()) {
1398 int path_index = ik->shared_classpath_index();
1399 ResourceMark rm;
1400 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1401 }
1402
1403 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1404 // Only dump the classes that can be stored into CDS archive
1405 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1406 ResourceMark rm(THREAD);
1407 classlist_file->print_cr("%s", ik->name()->as_C_string());
1408 classlist_file->flush();
1409 }
1410 }
1411
1412 // notify a class loaded from shared object
1413 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1414 }
1415
1416 ik->set_has_passed_fingerprint_check(false);
1417 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1418 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1419 uint64_t cds_fp = ik->get_stored_fingerprint();
1420 if (aot_fp != 0 && aot_fp == cds_fp) {
1421 // This class matches with a class saved in an AOT library
1422 ik->set_has_passed_fingerprint_check(true);
1423 } else {
1424 ResourceMark rm;
1425 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1426 }
1427 }
1428 return ik;
1429 }
1430 #endif // INCLUDE_CDS
1431
1432 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1433
1434 if (class_loader.is_null()) {
1435 ResourceMark rm;
1436 PackageEntry* pkg_entry = NULL;
1437 bool search_only_bootloader_append = false;
1438 ClassLoaderData *loader_data = class_loader_data(class_loader);
1439
1440 // Find the package in the boot loader's package entry table.
1441 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1442 if (pkg_name != NULL) {
1443 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1444 }
1445
1446 // Prior to attempting to load the class, enforce the boot loader's
1447 // visibility boundaries.
1448 if (!Universe::is_module_initialized()) {
1449 // During bootstrapping, prior to module initialization, any
1450 // class attempting to be loaded must be checked against the
1451 // java.base packages in the boot loader's PackageEntryTable.
1452 // No class outside of java.base is allowed to be loaded during
1453 // this bootstrapping window.
1454 if (!DumpSharedSpaces) {
1455 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1456 // Class is either in the unnamed package or in
1457 // a named package within the unnamed module. Either
1458 // case is outside of java.base, do not attempt to
1459 // load the class post java.base definition. If
1460 // java.base has not been defined, let the class load
1461 // and its package will be checked later by
1462 // ModuleEntryTable::verify_javabase_packages.
1463 if (ModuleEntryTable::javabase_defined()) {
1464 return NULL;
1465 }
1466 } else {
1467 // Check that the class' package is defined within java.base.
1468 ModuleEntry* mod_entry = pkg_entry->module();
1469 Symbol* mod_entry_name = mod_entry->name();
1470 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1471 return NULL;
1472 }
1473 }
1474 }
1475 } else {
1476 assert(!DumpSharedSpaces, "Archive dumped after module system initialization");
1477 // After the module system has been initialized, check if the class'
1478 // package is in a module defined to the boot loader.
1479 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1480 // Class is either in the unnamed package, in a named package
1481 // within a module not defined to the boot loader or in a
1482 // a named package within the unnamed module. In all cases,
1483 // limit visibility to search for the class only in the boot
1484 // loader's append path.
1485 search_only_bootloader_append = true;
1486 }
1487 }
1488
1489 // Prior to bootstrapping's module initialization, never load a class outside
1490 // of the boot loader's module path
1491 assert(Universe::is_module_initialized() || DumpSharedSpaces ||
1492 !search_only_bootloader_append,
1493 "Attempt to load a class outside of boot loader's module path");
1494
1495 // Search the shared system dictionary for classes preloaded into the
1496 // shared spaces.
1497 InstanceKlass* k = NULL;
1498 {
1499 #if INCLUDE_CDS
1500 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1501 k = load_shared_class(class_name, class_loader, THREAD);
1502 #endif
1503 }
1504
1505 if (k == NULL) {
1506 // Use VM class loader
1507 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1508 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1509 }
1510
1511 // find_or_define_instance_class may return a different InstanceKlass
1512 if (k != NULL) {
1513 InstanceKlass* defined_k =
1514 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1515 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1516 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1517 assert(defined_k != NULL, "Should have a klass if there's no exception");
1518 loader_data->add_to_deallocate_list(k);
1519 k = defined_k;
1520 } else if (HAS_PENDING_EXCEPTION) {
1521 loader_data->add_to_deallocate_list(k);
1522 return NULL;
1523 }
1524 }
1525 return k;
1526 } else {
1527 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1528 ResourceMark rm(THREAD);
1529
1530 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1531 JavaThread* jt = (JavaThread*) THREAD;
1532
1533 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1534 ClassLoader::perf_app_classload_selftime(),
1535 ClassLoader::perf_app_classload_count(),
1536 jt->get_thread_stat()->perf_recursion_counts_addr(),
1537 jt->get_thread_stat()->perf_timers_addr(),
1538 PerfClassTraceTime::CLASS_LOAD);
1539
1540 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1541 // Translate to external class name format, i.e., convert '/' chars to '.'
1542 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1543
1544 JavaValue result(T_OBJECT);
1545
1546 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1547
1548 // Call public unsynchronized loadClass(String) directly for all class loaders
1549 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1550 // acquire a class-name based lock rather than the class loader object lock.
1551 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1552 // so the call to loadClassInternal() was not required.
1553 //
1554 // UnsyncloadClass flag means both call loadClass(String) and do
1555 // not acquire the class loader lock even for class loaders that are
1556 // not parallelCapable. This was a risky transitional
1557 // flag for diagnostic purposes only. It is risky to call
1558 // custom class loaders without synchronization.
1559 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1560 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1561 // Do NOT assume this will be supported in future releases.
1562 //
1563 // Added MustCallLoadClassInternal in case we discover in the field
1564 // a customer that counts on this call
1565 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1566 JavaCalls::call_special(&result,
1567 class_loader,
1568 spec_klass,
1569 vmSymbols::loadClassInternal_name(),
1570 vmSymbols::string_class_signature(),
1571 string,
1572 CHECK_NULL);
1573 } else {
1574 JavaCalls::call_virtual(&result,
1575 class_loader,
1576 spec_klass,
1577 vmSymbols::loadClass_name(),
1578 vmSymbols::string_class_signature(),
1579 string,
1580 CHECK_NULL);
1581 }
1582
1583 assert(result.get_type() == T_OBJECT, "just checking");
1584 oop obj = (oop) result.get_jobject();
1585
1586 // Primitive classes return null since forName() can not be
1587 // used to obtain any of the Class objects representing primitives or void
1588 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1589 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1590 // For user defined Java class loaders, check that the name returned is
1591 // the same as that requested. This check is done for the bootstrap
1592 // loader when parsing the class file.
1593 if (class_name == k->name()) {
1594 return k;
1595 }
1596 }
1597 // Class is not found or has the wrong name, return NULL
1598 return NULL;
1599 }
1600 }
1601
1602 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1603
1604 HandleMark hm(THREAD);
1605 ClassLoaderData* loader_data = k->class_loader_data();
1606 Handle class_loader_h(THREAD, loader_data->class_loader());
1607
1608 // for bootstrap and other parallel classloaders don't acquire lock,
1609 // use placeholder token
1610 // If a parallelCapable class loader calls define_instance_class instead of
1611 // find_or_define_instance_class to get here, we have a timing
1612 // hole with systemDictionary updates and check_constraints
1613 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1614 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1615 compute_loader_lock_object(class_loader_h, THREAD)),
1616 "define called without lock");
1617 }
1618
1619 // Check class-loading constraints. Throw exception if violation is detected.
1620 // Grabs and releases SystemDictionary_lock
1621 // The check_constraints/find_class call and update_dictionary sequence
1622 // must be "atomic" for a specific class/classloader pair so we never
1623 // define two different instanceKlasses for that class/classloader pair.
1624 // Existing classloaders will call define_instance_class with the
1625 // classloader lock held
1626 // Parallel classloaders will call find_or_define_instance_class
1627 // which will require a token to perform the define class
1628 Symbol* name_h = k->name();
1629 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1630 int d_index = dictionary()->hash_to_index(d_hash);
1631 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1632
1633 // Register class just loaded with class loader (placed in Vector)
1634 // Note we do this before updating the dictionary, as this can
1635 // fail with an OutOfMemoryError (if it does, we will *not* put this
1636 // class in the dictionary and will not update the class hierarchy).
1637 // JVMTI FollowReferences needs to find the classes this way.
1638 if (k->class_loader() != NULL) {
1639 methodHandle m(THREAD, Universe::loader_addClass_method());
1640 JavaValue result(T_VOID);
1641 JavaCallArguments args(class_loader_h);
1642 args.push_oop(Handle(THREAD, k->java_mirror()));
1643 JavaCalls::call(&result, m, &args, CHECK);
1644 }
1645
1646 // Add the new class. We need recompile lock during update of CHA.
1647 {
1648 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1649 int p_index = placeholders()->hash_to_index(p_hash);
1650
1651 MutexLocker mu_r(Compile_lock, THREAD);
1652
1653 // Add to class hierarchy, initialize vtables, and do possible
1654 // deoptimizations.
1655 add_to_hierarchy(k, CHECK); // No exception, but can block
1656
1657 // Add to systemDictionary - so other classes can see it.
1658 // Grabs and releases SystemDictionary_lock
1659 update_dictionary(d_index, d_hash, p_index, p_hash,
1660 k, class_loader_h, THREAD);
1661 }
1662 k->eager_initialize(THREAD);
1663
1664 // notify jvmti
1665 if (JvmtiExport::should_post_class_load()) {
1666 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1667 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1668
1669 }
1670 class_define_event(k, loader_data);
1671 }
1672
1673 // Support parallel classloading
1674 // All parallel class loaders, including bootstrap classloader
1675 // lock a placeholder entry for this class/class_loader pair
1676 // to allow parallel defines of different classes for this class loader
1677 // With AllowParallelDefine flag==true, in case they do not synchronize around
1678 // FindLoadedClass/DefineClass, calls, we check for parallel
1679 // loading for them, wait if a defineClass is in progress
1680 // and return the initial requestor's results
1681 // This flag does not apply to the bootstrap classloader.
1682 // With AllowParallelDefine flag==false, call through to define_instance_class
1683 // which will throw LinkageError: duplicate class definition.
1684 // False is the requested default.
1685 // For better performance, the class loaders should synchronize
1686 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1687 // potentially waste time reading and parsing the bytestream.
1688 // Note: VM callers should ensure consistency of k/class_name,class_loader
1689 // Be careful when modifying this code: once you have run
1690 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1691 // you need to find_and_remove it before returning.
1692 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1693 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1694 InstanceKlass* k, TRAPS) {
1695
1696 Symbol* name_h = k->name(); // passed in class_name may be null
1697 ClassLoaderData* loader_data = class_loader_data(class_loader);
1698
1699 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1700 int d_index = dictionary()->hash_to_index(d_hash);
1701
1702 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1703 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1704 int p_index = placeholders()->hash_to_index(p_hash);
1705 PlaceholderEntry* probe;
1706
1707 {
1708 MutexLocker mu(SystemDictionary_lock, THREAD);
1709 // First check if class already defined
1710 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1711 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1712 if (check != NULL) {
1713 return check;
1714 }
1715 }
1716
1717 // Acquire define token for this class/classloader
1718 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1719 // Wait if another thread defining in parallel
1720 // All threads wait - even those that will throw duplicate class: otherwise
1721 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1722 // if other thread has not finished updating dictionary
1723 while (probe->definer() != NULL) {
1724 SystemDictionary_lock->wait();
1725 }
1726 // Only special cases allow parallel defines and can use other thread's results
1727 // Other cases fall through, and may run into duplicate defines
1728 // caught by finding an entry in the SystemDictionary
1729 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1730 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1731 SystemDictionary_lock->notify_all();
1732 #ifdef ASSERT
1733 InstanceKlass* check = find_class(d_index, d_hash, name_h, loader_data);
1734 assert(check != NULL, "definer missed recording success");
1735 #endif
1736 return probe->instance_klass();
1737 } else {
1738 // This thread will define the class (even if earlier thread tried and had an error)
1739 probe->set_definer(THREAD);
1740 }
1741 }
1742
1743 define_instance_class(k, THREAD);
1744
1745 Handle linkage_exception = Handle(); // null handle
1746
1747 // definer must notify any waiting threads
1748 {
1749 MutexLocker mu(SystemDictionary_lock, THREAD);
1750 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1751 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1752 if (probe != NULL) {
1753 if (HAS_PENDING_EXCEPTION) {
1754 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1755 CLEAR_PENDING_EXCEPTION;
1756 } else {
1757 probe->set_instance_klass(k);
1758 }
1759 probe->set_definer(NULL);
1760 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1761 SystemDictionary_lock->notify_all();
1762 }
1763 }
1764
1765 // Can't throw exception while holding lock due to rank ordering
1766 if (linkage_exception() != NULL) {
1767 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1768 }
1769
1770 return k;
1771 }
1772 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1773 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1774 if (class_loader.is_null()) {
1775 return Handle(THREAD, _system_loader_lock_obj);
1776 } else {
1777 return class_loader;
1778 }
1779 }
1780
1781 // This method is added to check how often we have to wait to grab loader
1782 // lock. The results are being recorded in the performance counters defined in
1783 // ClassLoader::_sync_systemLoaderLockContentionRate and
1784 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1785 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1786 if (!UsePerfData) {
1787 return;
1788 }
1789
1790 assert(!loader_lock.is_null(), "NULL lock object");
1791
1792 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1793 == ObjectSynchronizer::owner_other) {
1794 // contention will likely happen, so increment the corresponding
1795 // contention counter.
1796 if (loader_lock() == _system_loader_lock_obj) {
1797 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1798 } else {
1799 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1800 }
1801 }
1802 }
1803
1804 // ----------------------------------------------------------------------------
1805 // Lookup
1806
1807 InstanceKlass* SystemDictionary::find_class(int index, unsigned int hash,
1808 Symbol* class_name,
1809 ClassLoaderData* loader_data) {
1810 assert_locked_or_safepoint(SystemDictionary_lock);
1811 assert (index == dictionary()->index_for(class_name, loader_data),
1812 "incorrect index?");
1813
1814 return dictionary()->find_class(index, hash, class_name, loader_data);
1815 }
1816
1817
1818 // Basic find on classes in the midst of being loaded
1819 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1820 ClassLoaderData* loader_data) {
1821 assert_locked_or_safepoint(SystemDictionary_lock);
1822 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1823 int p_index = placeholders()->hash_to_index(p_hash);
1824 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1825 }
1826
1827
1828 // Used for assertions and verification only
1829 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1830 #ifndef ASSERT
1831 guarantee(VerifyBeforeGC ||
1832 VerifyDuringGC ||
1833 VerifyBeforeExit ||
1834 VerifyDuringStartup ||
1835 VerifyAfterGC, "too expensive");
1836 #endif
1837 assert_locked_or_safepoint(SystemDictionary_lock);
1838
1839 // First look in the loaded class array
1840 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1841 int d_index = dictionary()->hash_to_index(d_hash);
1842 return find_class(d_index, d_hash, class_name, loader_data);
1843 }
1844
1845
1846 // Get the next class in the dictionary.
1847 Klass* SystemDictionary::try_get_next_class() {
1848 return dictionary()->try_get_next_class();
1849 }
1850
1851
1852 // ----------------------------------------------------------------------------
1853 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1854 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1855 // before a new class is used.
1856
1857 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1858 assert(k != NULL, "just checking");
1859 assert_locked_or_safepoint(Compile_lock);
1860
1861 // Link into hierachy. Make sure the vtables are initialized before linking into
1862 k->append_to_sibling_list(); // add to superklass/sibling list
1863 k->process_interfaces(THREAD); // handle all "implements" declarations
1864 k->set_init_state(InstanceKlass::loaded);
1865 // Now flush all code that depended on old class hierarchy.
1866 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1867 // Also, first reinitialize vtable because it may have gotten out of synch
1868 // while the new class wasn't connected to the class hierarchy.
1869 CodeCache::flush_dependents_on(k);
1870 }
1871
1872 // ----------------------------------------------------------------------------
1873 // GC support
1874
1875 // Following roots during mark-sweep is separated in two phases.
1876 //
1877 // The first phase follows preloaded classes and all other system
1878 // classes, since these will never get unloaded anyway.
1879 //
1880 // The second phase removes (unloads) unreachable classes from the
1881 // system dictionary and follows the remaining classes' contents.
1882
1883 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1884 roots_oops_do(blk, NULL);
1885 }
1886
1887 // Calculate a "good" systemdictionary size based
1888 // on predicted or current loaded classes count
1889 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1890 int newsize = _old_default_sdsize;
1891 if ((classcount > 0) && !DumpSharedSpaces) {
1892 int desiredsize = classcount/_average_depth_goal;
1893 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1894 newsize = _primelist[++_sdgeneration]) {
1895 if (desiredsize <= newsize) {
1896 break;
1897 }
1898 }
1899 }
1900 return newsize;
1901 }
1902
1903 #ifdef ASSERT
1904 class VerifySDReachableAndLiveClosure : public OopClosure {
1905 private:
1906 BoolObjectClosure* _is_alive;
1907
1908 template <class T> void do_oop_work(T* p) {
1909 oop obj = oopDesc::load_decode_heap_oop(p);
1910 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1911 }
1912
1913 public:
1914 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1915
1916 virtual void do_oop(oop* p) { do_oop_work(p); }
1917 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1918 };
1919 #endif
1920
1921 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1922 // Note: anonymous classes are not in the SD.
1923 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive,
1924 GCTimer* gc_timer,
1925 bool do_cleaning) {
1926
1927
1928 bool unloading_occurred;
1929 {
1930 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1931
1932 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1933 unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive,
1934 do_cleaning);
1935 }
1936
1937 if (unloading_occurred) {
1938 GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
1939 dictionary()->do_unloading();
1940 constraints()->purge_loader_constraints();
1941 resolution_errors()->purge_resolution_errors();
1942 }
1943
1944 {
1945 GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
1946 // Oops referenced by the system dictionary may get unreachable independently
1947 // of the class loader (eg. cached protection domain oops). So we need to
1948 // explicitly unlink them here instead of in Dictionary::do_unloading.
1949 dictionary()->unlink(is_alive);
1950 #ifdef ASSERT
1951 VerifySDReachableAndLiveClosure cl(is_alive);
1952 dictionary()->oops_do(&cl);
1953 #endif
1954 }
1955
1956 if (do_cleaning) {
1957 GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
1958 ResolvedMethodTable::unlink(is_alive);
1959 }
1960
1961 return unloading_occurred;
1962 }
1963
1964 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1965 strong->do_oop(&_java_system_loader);
1966 strong->do_oop(&_system_loader_lock_obj);
1967 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1968
1969 // Adjust dictionary
1970 dictionary()->roots_oops_do(strong, weak);
1971
1972 // Visit extra methods
1973 invoke_method_table()->oops_do(strong);
1974
1975 if (weak != NULL) {
1976 ResolvedMethodTable::oops_do(weak);
1977 }
1978 }
1979
1980 void SystemDictionary::oops_do(OopClosure* f) {
1981 f->do_oop(&_java_system_loader);
1982 f->do_oop(&_system_loader_lock_obj);
1983 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1984
1985 // Adjust dictionary
1986 dictionary()->oops_do(f);
1987
1988 // Visit extra methods
1989 invoke_method_table()->oops_do(f);
1990
1991 ResolvedMethodTable::oops_do(f);
1992 }
1993
1994 // Just the classes from defining class loaders
1995 // Don't iterate over placeholders
1996 void SystemDictionary::classes_do(void f(Klass*)) {
1997 dictionary()->classes_do(f);
1998 }
1999
2000 // Added for initialize_itable_for_klass
2001 // Just the classes from defining class loaders
2002 // Don't iterate over placeholders
2003 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
2004 dictionary()->classes_do(f, CHECK);
2005 }
2006
2007 // All classes, and their class loaders
2008 // Don't iterate over placeholders
2009 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
2010 dictionary()->classes_do(f);
2011 }
2012
2013 void SystemDictionary::methods_do(void f(Method*)) {
2014 // Walk methods in loaded classes
2015 ClassLoaderDataGraph::methods_do(f);
2016 // Walk method handle intrinsics
2017 invoke_method_table()->methods_do(f);
2018 }
2019
2020 void SystemDictionary::remove_classes_in_error_state() {
2021 dictionary()->remove_classes_in_error_state();
2022 }
2023
2024 // ----------------------------------------------------------------------------
2025 // Lazily load klasses
2026
2027 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
2028 // if multiple threads calling this function, only one thread will load
2029 // the class. The other threads will find the loaded version once the
2030 // class is loaded.
2031 Klass* aos = _abstract_ownable_synchronizer_klass;
2032 if (aos == NULL) {
2033 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
2034 // Force a fence to prevent any read before the write completes
2035 OrderAccess::fence();
2036 _abstract_ownable_synchronizer_klass = InstanceKlass::cast(k);
2037 }
2038 }
2039
2040 // ----------------------------------------------------------------------------
2041 // Initialization
2042
2043 void SystemDictionary::initialize(TRAPS) {
2044 // Allocate arrays
2045 assert(dictionary() == NULL,
2046 "SystemDictionary should only be initialized once");
2047 _sdgeneration = 0;
2048 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
2049 _placeholders = new PlaceholderTable(_nof_buckets);
2050 _number_of_modifications = 0;
2051 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2052 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2053 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2054
2055 // Allocate private object used as system class loader lock
2056 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2057 // Initialize basic classes
2058 initialize_preloaded_classes(CHECK);
2059 }
2060
2061 // Compact table of directions on the initialization of klasses:
2062 static const short wk_init_info[] = {
2063 #define WK_KLASS_INIT_INFO(name, symbol, option) \
2064 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
2065 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
2066 | (int)SystemDictionary::option ),
2067 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2068 #undef WK_KLASS_INIT_INFO
2069 0
2070 };
2071
2072 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
2073 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2074 int info = wk_init_info[id - FIRST_WKID];
2075 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2076 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2077 InstanceKlass** klassp = &_well_known_klasses[id];
2078
2079 bool must_load;
2080 #if INCLUDE_JVMCI
2081 if (EnableJVMCI) {
2082 // If JVMCI is enabled we require its classes to be found.
2083 must_load = (init_opt < SystemDictionary::Opt) || (init_opt == SystemDictionary::Jvmci);
2084 } else
2085 #endif
2086 {
2087 must_load = (init_opt < SystemDictionary::Opt);
2088 }
2089
2090 if ((*klassp) == NULL) {
2091 Klass* k;
2092 if (must_load) {
2093 k = resolve_or_fail(symbol, true, CHECK_0); // load required class
2094 } else {
2095 k = resolve_or_null(symbol, CHECK_0); // load optional klass
2096 }
2097 (*klassp) = (k == NULL) ? NULL : InstanceKlass::cast(k);
2098 }
2099 return ((*klassp) != NULL);
2100 }
2101
2102 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2103 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2104 for (int id = (int)start_id; id < (int)limit_id; id++) {
2105 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2106 int info = wk_init_info[id - FIRST_WKID];
2107 int sid = (info >> CEIL_LG_OPTION_LIMIT);
2108 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
2109
2110 initialize_wk_klass((WKID)id, opt, CHECK);
2111 }
2112
2113 // move the starting value forward to the limit:
2114 start_id = limit_id;
2115 }
2116
2117 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
2118 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
2119
2120 // Create the ModuleEntry for java.base. This call needs to be done here,
2121 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2122 ClassLoader::classLoader_init2(CHECK);
2123
2124 // Preload commonly used klasses
2125 WKID scan = FIRST_WKID;
2126 // first do Object, then String, Class
2127 #if INCLUDE_CDS
2128 if (UseSharedSpaces) {
2129 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2130 // Initialize the constant pool for the Object_class
2131 Object_klass()->constants()->restore_unshareable_info(CHECK);
2132 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2133 } else
2134 #endif
2135 {
2136 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2137 }
2138
2139 // Calculate offsets for String and Class classes since they are loaded and
2140 // can be used after this point.
2141 java_lang_String::compute_offsets();
2142 java_lang_Class::compute_offsets();
2143
2144 // Fixup mirrors for classes loaded before java.lang.Class.
2145 // These calls iterate over the objects currently in the perm gen
2146 // so calling them at this point is matters (not before when there
2147 // are fewer objects and not later after there are more objects
2148 // in the perm gen.
2149 Universe::initialize_basic_type_mirrors(CHECK);
2150 Universe::fixup_mirrors(CHECK);
2151
2152 // do a bunch more:
2153 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2154
2155 // Preload ref klasses and set reference types
2156 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2157 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2158
2159 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2160 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2161 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2162 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2163 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2164
2165 // JSR 292 classes
2166 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2167 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2168 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2169 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2170 initialize_wk_klasses_until(NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID), scan, CHECK);
2171
2172 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2173 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2174 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2175 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2176 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2177 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2178 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2179 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2180 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2181 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2182
2183 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2184 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2185 _has_loadClassInternal = (method != NULL);
2186 }
2187 { // Compute whether we should use checkPackageAccess or NOT
2188 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2189 _has_checkPackageAccess = (method != NULL);
2190 }
2191 }
2192
2193 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2194 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2195 BasicType SystemDictionary::box_klass_type(Klass* k) {
2196 assert(k != NULL, "");
2197 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2198 if (_box_klasses[i] == k)
2199 return (BasicType)i;
2200 }
2201 return T_OBJECT;
2202 }
2203
2204 // Constraints on class loaders. The details of the algorithm can be
2205 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2206 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2207 // that the system dictionary needs to maintain a set of contraints that
2208 // must be satisfied by all classes in the dictionary.
2209 // if defining is true, then LinkageError if already in systemDictionary
2210 // if initiating loader, then ok if InstanceKlass matches existing entry
2211
2212 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2213 InstanceKlass* k,
2214 Handle class_loader, bool defining,
2215 TRAPS) {
2216 const char *linkage_error1 = NULL;
2217 const char *linkage_error2 = NULL;
2218 {
2219 Symbol* name = k->name();
2220 ClassLoaderData *loader_data = class_loader_data(class_loader);
2221
2222 MutexLocker mu(SystemDictionary_lock, THREAD);
2223
2224 InstanceKlass* check = find_class(d_index, d_hash, name, loader_data);
2225 if (check != NULL) {
2226 // if different InstanceKlass - duplicate class definition,
2227 // else - ok, class loaded by a different thread in parallel,
2228 // we should only have found it if it was done loading and ok to use
2229 // system dictionary only holds instance classes, placeholders
2230 // also holds array classes
2231
2232 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2233 if ((defining == true) || (k != check)) {
2234 linkage_error1 = "loader (instance of ";
2235 linkage_error2 = "): attempted duplicate class definition for name: \"";
2236 } else {
2237 return;
2238 }
2239 }
2240
2241 #ifdef ASSERT
2242 Symbol* ph_check = find_placeholder(name, loader_data);
2243 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2244 #endif
2245
2246 if (linkage_error1 == NULL) {
2247 if (constraints()->check_or_update(k, class_loader, name) == false) {
2248 linkage_error1 = "loader constraint violation: loader (instance of ";
2249 linkage_error2 = ") previously initiated loading for a different type with name \"";
2250 }
2251 }
2252 }
2253
2254 // Throw error now if needed (cannot throw while holding
2255 // SystemDictionary_lock because of rank ordering)
2256
2257 if (linkage_error1) {
2258 ResourceMark rm(THREAD);
2259 const char* class_loader_name = loader_name(class_loader());
2260 char* type_name = k->name()->as_C_string();
2261 size_t buflen = strlen(linkage_error1) + strlen(class_loader_name) +
2262 strlen(linkage_error2) + strlen(type_name) + 2; // +2 for '"' and null byte.
2263 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2264 jio_snprintf(buf, buflen, "%s%s%s%s\"", linkage_error1, class_loader_name, linkage_error2, type_name);
2265 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2266 }
2267 }
2268
2269
2270 // Update system dictionary - done after check_constraint and add_to_hierachy
2271 // have been called.
2272 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2273 int p_index, unsigned int p_hash,
2274 InstanceKlass* k,
2275 Handle class_loader,
2276 TRAPS) {
2277 // Compile_lock prevents systemDictionary updates during compilations
2278 assert_locked_or_safepoint(Compile_lock);
2279 Symbol* name = k->name();
2280 ClassLoaderData *loader_data = class_loader_data(class_loader);
2281
2282 {
2283 MutexLocker mu1(SystemDictionary_lock, THREAD);
2284
2285 // See whether biased locking is enabled and if so set it for this
2286 // klass.
2287 // Note that this must be done past the last potential blocking
2288 // point / safepoint. We enable biased locking lazily using a
2289 // VM_Operation to iterate the SystemDictionary and installing the
2290 // biasable mark word into each InstanceKlass's prototype header.
2291 // To avoid race conditions where we accidentally miss enabling the
2292 // optimization for one class in the process of being added to the
2293 // dictionary, we must not safepoint after the test of
2294 // BiasedLocking::enabled().
2295 if (UseBiasedLocking && BiasedLocking::enabled()) {
2296 // Set biased locking bit for all loaded classes; it will be
2297 // cleared if revocation occurs too often for this type
2298 // NOTE that we must only do this when the class is initally
2299 // defined, not each time it is referenced from a new class loader
2300 if (k->class_loader() == class_loader()) {
2301 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2302 }
2303 }
2304
2305 // Make a new system dictionary entry.
2306 InstanceKlass* sd_check = find_class(d_index, d_hash, name, loader_data);
2307 if (sd_check == NULL) {
2308 dictionary()->add_klass(name, loader_data, k);
2309 notice_modification();
2310 }
2311 #ifdef ASSERT
2312 sd_check = find_class(d_index, d_hash, name, loader_data);
2313 assert (sd_check != NULL, "should have entry in system dictionary");
2314 // Note: there may be a placeholder entry: for circularity testing
2315 // or for parallel defines
2316 #endif
2317 SystemDictionary_lock->notify_all();
2318 }
2319 }
2320
2321
2322 // Try to find a class name using the loader constraints. The
2323 // loader constraints might know about a class that isn't fully loaded
2324 // yet and these will be ignored.
2325 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2326 Symbol* class_name, Handle class_loader, TRAPS) {
2327
2328 // First see if it has been loaded directly.
2329 // Force the protection domain to be null. (This removes protection checks.)
2330 Handle no_protection_domain;
2331 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2332 no_protection_domain, CHECK_NULL);
2333 if (klass != NULL)
2334 return klass;
2335
2336 // Now look to see if it has been loaded elsewhere, and is subject to
2337 // a loader constraint that would require this loader to return the
2338 // klass that is already loaded.
2339 if (FieldType::is_array(class_name)) {
2340 // For array classes, their Klass*s are not kept in the
2341 // constraint table. The element Klass*s are.
2342 FieldArrayInfo fd;
2343 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2344 if (t != T_OBJECT) {
2345 klass = Universe::typeArrayKlassObj(t);
2346 } else {
2347 MutexLocker mu(SystemDictionary_lock, THREAD);
2348 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2349 }
2350 // If element class already loaded, allocate array klass
2351 if (klass != NULL) {
2352 klass = klass->array_klass_or_null(fd.dimension());
2353 }
2354 } else {
2355 MutexLocker mu(SystemDictionary_lock, THREAD);
2356 // Non-array classes are easy: simply check the constraint table.
2357 klass = constraints()->find_constrained_klass(class_name, class_loader);
2358 }
2359
2360 return klass;
2361 }
2362
2363
2364 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2365 Handle class_loader1,
2366 Handle class_loader2,
2367 Thread* THREAD) {
2368 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2369 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2370
2371 Symbol* constraint_name = NULL;
2372 if (!FieldType::is_array(class_name)) {
2373 constraint_name = class_name;
2374 } else {
2375 // For array classes, their Klass*s are not kept in the
2376 // constraint table. The element classes are.
2377 FieldArrayInfo fd;
2378 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2379 // primitive types always pass
2380 if (t != T_OBJECT) {
2381 return true;
2382 } else {
2383 constraint_name = fd.object_key();
2384 }
2385 }
2386 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2387 int d_index1 = dictionary()->hash_to_index(d_hash1);
2388
2389 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2390 int d_index2 = dictionary()->hash_to_index(d_hash2);
2391 {
2392 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2393
2394 // Better never do a GC while we're holding these oops
2395 NoSafepointVerifier nosafepoint;
2396
2397 InstanceKlass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2398 InstanceKlass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2399 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2400 klass2, class_loader2);
2401 }
2402 }
2403
2404 // Add entry to resolution error table to record the error when the first
2405 // attempt to resolve a reference to a class has failed.
2406 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2407 Symbol* error, Symbol* message) {
2408 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2409 int index = resolution_errors()->hash_to_index(hash);
2410 {
2411 MutexLocker ml(SystemDictionary_lock, Thread::current());
2412 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2413 }
2414 }
2415
2416 // Delete a resolution error for RedefineClasses for a constant pool is going away
2417 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2418 resolution_errors()->delete_entry(pool);
2419 }
2420
2421 // Lookup resolution error table. Returns error if found, otherwise NULL.
2422 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2423 Symbol** message) {
2424 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2425 int index = resolution_errors()->hash_to_index(hash);
2426 {
2427 MutexLocker ml(SystemDictionary_lock, Thread::current());
2428 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2429 if (entry != NULL) {
2430 *message = entry->message();
2431 return entry->error();
2432 } else {
2433 return NULL;
2434 }
2435 }
2436 }
2437
2438
2439 // Signature constraints ensure that callers and callees agree about
2440 // the meaning of type names in their signatures. This routine is the
2441 // intake for constraints. It collects them from several places:
2442 //
2443 // * LinkResolver::resolve_method (if check_access is true) requires
2444 // that the resolving class (the caller) and the defining class of
2445 // the resolved method (the callee) agree on each type in the
2446 // method's signature.
2447 //
2448 // * LinkResolver::resolve_interface_method performs exactly the same
2449 // checks.
2450 //
2451 // * LinkResolver::resolve_field requires that the constant pool
2452 // attempting to link to a field agree with the field's defining
2453 // class about the type of the field signature.
2454 //
2455 // * klassVtable::initialize_vtable requires that, when a class
2456 // overrides a vtable entry allocated by a superclass, that the
2457 // overriding method (i.e., the callee) agree with the superclass
2458 // on each type in the method's signature.
2459 //
2460 // * klassItable::initialize_itable requires that, when a class fills
2461 // in its itables, for each non-abstract method installed in an
2462 // itable, the method (i.e., the callee) agree with the interface
2463 // on each type in the method's signature.
2464 //
2465 // All those methods have a boolean (check_access, checkconstraints)
2466 // which turns off the checks. This is used from specialized contexts
2467 // such as bootstrapping, dumping, and debugging.
2468 //
2469 // No direct constraint is placed between the class and its
2470 // supertypes. Constraints are only placed along linked relations
2471 // between callers and callees. When a method overrides or implements
2472 // an abstract method in a supertype (superclass or interface), the
2473 // constraints are placed as if the supertype were the caller to the
2474 // overriding method. (This works well, since callers to the
2475 // supertype have already established agreement between themselves and
2476 // the supertype.) As a result of all this, a class can disagree with
2477 // its supertype about the meaning of a type name, as long as that
2478 // class neither calls a relevant method of the supertype, nor is
2479 // called (perhaps via an override) from the supertype.
2480 //
2481 //
2482 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2483 //
2484 // Make sure all class components (including arrays) in the given
2485 // signature will be resolved to the same class in both loaders.
2486 // Returns the name of the type that failed a loader constraint check, or
2487 // NULL if no constraint failed. No exception except OOME is thrown.
2488 // Arrays are not added to the loader constraint table, their elements are.
2489 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2490 Handle loader1, Handle loader2,
2491 bool is_method, TRAPS) {
2492 // Nothing to do if loaders are the same.
2493 if (loader1() == loader2()) {
2494 return NULL;
2495 }
2496
2497 SignatureStream sig_strm(signature, is_method);
2498 while (!sig_strm.is_done()) {
2499 if (sig_strm.is_object()) {
2500 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2501 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2502 return sig;
2503 }
2504 }
2505 sig_strm.next();
2506 }
2507 return NULL;
2508 }
2509
2510
2511 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2512 Symbol* signature,
2513 TRAPS) {
2514 methodHandle empty;
2515 assert(MethodHandles::is_signature_polymorphic(iid) &&
2516 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2517 iid != vmIntrinsics::_invokeGeneric,
2518 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2519
2520 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2521 int index = invoke_method_table()->hash_to_index(hash);
2522 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2523 methodHandle m;
2524 if (spe == NULL || spe->method() == NULL) {
2525 spe = NULL;
2526 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2527 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2528 if (!Arguments::is_interpreter_only()) {
2529 // Generate a compiled form of the MH intrinsic.
2530 AdapterHandlerLibrary::create_native_wrapper(m);
2531 // Check if have the compiled code.
2532 if (!m->has_compiled_code()) {
2533 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2534 "Out of space in CodeCache for method handle intrinsic", empty);
2535 }
2536 }
2537 // Now grab the lock. We might have to throw away the new method,
2538 // if a racing thread has managed to install one at the same time.
2539 {
2540 MutexLocker ml(SystemDictionary_lock, THREAD);
2541 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2542 if (spe == NULL)
2543 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2544 if (spe->method() == NULL)
2545 spe->set_method(m());
2546 }
2547 }
2548
2549 assert(spe != NULL && spe->method() != NULL, "");
2550 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2551 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2552 "MH intrinsic invariant");
2553 return spe->method();
2554 }
2555
2556 // Helper for unpacking the return value from linkMethod and linkCallSite.
2557 static methodHandle unpack_method_and_appendix(Handle mname,
2558 Klass* accessing_klass,
2559 objArrayHandle appendix_box,
2560 Handle* appendix_result,
2561 TRAPS) {
2562 methodHandle empty;
2563 if (mname.not_null()) {
2564 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2565 if (m != NULL) {
2566 oop appendix = appendix_box->obj_at(0);
2567 if (TraceMethodHandles) {
2568 #ifndef PRODUCT
2569 ttyLocker ttyl;
2570 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2571 m->print();
2572 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2573 tty->cr();
2574 #endif //PRODUCT
2575 }
2576 (*appendix_result) = Handle(THREAD, appendix);
2577 // the target is stored in the cpCache and if a reference to this
2578 // MethodName is dropped we need a way to make sure the
2579 // class_loader containing this method is kept alive.
2580 // FIXME: the appendix might also preserve this dependency.
2581 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2582 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2583 return methodHandle(THREAD, m);
2584 }
2585 }
2586 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2587 return empty;
2588 }
2589
2590 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2591 Symbol* name,
2592 Symbol* signature,
2593 Klass* accessing_klass,
2594 Handle *appendix_result,
2595 Handle *method_type_result,
2596 TRAPS) {
2597 methodHandle empty;
2598 assert(THREAD->can_call_java() ,"");
2599 Handle method_type =
2600 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2601
2602 int ref_kind = JVM_REF_invokeVirtual;
2603 oop name_oop = StringTable::intern(name, CHECK_(empty));
2604 Handle name_str (THREAD, name_oop);
2605 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2606 assert(appendix_box->obj_at(0) == NULL, "");
2607
2608 // This should not happen. JDK code should take care of that.
2609 if (accessing_klass == NULL || method_type.is_null()) {
2610 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2611 }
2612
2613 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2614 JavaCallArguments args;
2615 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2616 args.push_int(ref_kind);
2617 args.push_oop(Handle(THREAD, klass->java_mirror()));
2618 args.push_oop(name_str);
2619 args.push_oop(method_type);
2620 args.push_oop(appendix_box);
2621 JavaValue result(T_OBJECT);
2622 JavaCalls::call_static(&result,
2623 SystemDictionary::MethodHandleNatives_klass(),
2624 vmSymbols::linkMethod_name(),
2625 vmSymbols::linkMethod_signature(),
2626 &args, CHECK_(empty));
2627 Handle mname(THREAD, (oop) result.get_jobject());
2628 (*method_type_result) = method_type;
2629 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2630 }
2631
2632 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2633 // We must ensure that all class loaders everywhere will reach this class, for any client.
2634 // This is a safe bet for public classes in java.lang, such as Object and String.
2635 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2636 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2637 static bool is_always_visible_class(oop mirror) {
2638 Klass* klass = java_lang_Class::as_Klass(mirror);
2639 if (klass->is_objArray_klass()) {
2640 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2641 }
2642 if (klass->is_typeArray_klass()) {
2643 return true; // primitive array
2644 }
2645 assert(klass->is_instance_klass(), "%s", klass->external_name());
2646 return klass->is_public() &&
2647 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2648 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2649 }
2650
2651 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2652 // signature, as interpreted relative to the given class loader.
2653 // Because of class loader constraints, all method handle usage must be
2654 // consistent with this loader.
2655 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2656 Klass* accessing_klass,
2657 TRAPS) {
2658 Handle empty;
2659 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2660 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2661 int index = invoke_method_table()->hash_to_index(hash);
2662 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2663 if (spe != NULL && spe->method_type() != NULL) {
2664 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2665 return Handle(THREAD, spe->method_type());
2666 } else if (!THREAD->can_call_java()) {
2667 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2668 return Handle(); // do not attempt from within compiler, unless it was cached
2669 }
2670
2671 Handle class_loader, protection_domain;
2672 if (accessing_klass != NULL) {
2673 class_loader = Handle(THREAD, accessing_klass->class_loader());
2674 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2675 }
2676 bool can_be_cached = true;
2677 int npts = ArgumentCount(signature).size();
2678 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2679 int arg = 0;
2680 Handle rt; // the return type from the signature
2681 ResourceMark rm(THREAD);
2682 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2683 oop mirror = NULL;
2684 if (can_be_cached) {
2685 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2686 mirror = ss.as_java_mirror(Handle(), Handle(),
2687 SignatureStream::ReturnNull, CHECK_(empty));
2688 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2689 // Fall back to accessing_klass context.
2690 can_be_cached = false;
2691 }
2692 }
2693 if (!can_be_cached) {
2694 // Resolve, throwing a real error if it doesn't work.
2695 mirror = ss.as_java_mirror(class_loader, protection_domain,
2696 SignatureStream::NCDFError, CHECK_(empty));
2697 }
2698 assert(!oopDesc::is_null(mirror), "%s", ss.as_symbol(THREAD)->as_C_string());
2699 if (ss.at_return_type())
2700 rt = Handle(THREAD, mirror);
2701 else
2702 pts->obj_at_put(arg++, mirror);
2703
2704 // Check accessibility.
2705 if (ss.is_object() && accessing_klass != NULL) {
2706 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2707 mirror = NULL; // safety
2708 // Emulate ConstantPool::verify_constant_pool_resolve.
2709 if (sel_klass->is_objArray_klass())
2710 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2711 if (sel_klass->is_instance_klass()) {
2712 LinkResolver::check_klass_accessability(accessing_klass, sel_klass, CHECK_(empty));
2713 }
2714 }
2715 }
2716 assert(arg == npts, "");
2717
2718 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2719 JavaCallArguments args(Handle(THREAD, rt()));
2720 args.push_oop(pts);
2721 JavaValue result(T_OBJECT);
2722 JavaCalls::call_static(&result,
2723 SystemDictionary::MethodHandleNatives_klass(),
2724 vmSymbols::findMethodHandleType_name(),
2725 vmSymbols::findMethodHandleType_signature(),
2726 &args, CHECK_(empty));
2727 Handle method_type(THREAD, (oop) result.get_jobject());
2728
2729 if (can_be_cached) {
2730 // We can cache this MethodType inside the JVM.
2731 MutexLocker ml(SystemDictionary_lock, THREAD);
2732 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2733 if (spe == NULL)
2734 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2735 if (spe->method_type() == NULL) {
2736 spe->set_method_type(method_type());
2737 }
2738 }
2739
2740 // report back to the caller with the MethodType
2741 return method_type;
2742 }
2743
2744 // Ask Java code to find or construct a method handle constant.
2745 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2746 int ref_kind, //e.g., JVM_REF_invokeVirtual
2747 Klass* callee,
2748 Symbol* name_sym,
2749 Symbol* signature,
2750 TRAPS) {
2751 Handle empty;
2752 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2753 Handle type;
2754 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2755 type = find_method_handle_type(signature, caller, CHECK_(empty));
2756 } else if (caller == NULL) {
2757 // This should not happen. JDK code should take care of that.
2758 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2759 } else {
2760 ResourceMark rm(THREAD);
2761 SignatureStream ss(signature, false);
2762 if (!ss.is_done()) {
2763 oop mirror = ss.as_java_mirror(Handle(THREAD, caller->class_loader()),
2764 Handle(THREAD, caller->protection_domain()),
2765 SignatureStream::NCDFError, CHECK_(empty));
2766 type = Handle(THREAD, mirror);
2767 ss.next();
2768 if (!ss.is_done()) type = Handle(); // error!
2769 }
2770 }
2771 if (type.is_null()) {
2772 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2773 }
2774
2775 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2776 JavaCallArguments args;
2777 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2778 args.push_int(ref_kind);
2779 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2780 args.push_oop(name);
2781 args.push_oop(type);
2782 JavaValue result(T_OBJECT);
2783 JavaCalls::call_static(&result,
2784 SystemDictionary::MethodHandleNatives_klass(),
2785 vmSymbols::linkMethodHandleConstant_name(),
2786 vmSymbols::linkMethodHandleConstant_signature(),
2787 &args, CHECK_(empty));
2788 return Handle(THREAD, (oop) result.get_jobject());
2789 }
2790
2791 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2792 // name and signature, as interpreted relative to the given class loader.
2793 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2794 Handle bootstrap_specifier,
2795 Symbol* name,
2796 Symbol* type,
2797 Handle *appendix_result,
2798 Handle *method_type_result,
2799 TRAPS) {
2800 methodHandle empty;
2801 Handle bsm, info;
2802 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2803 bsm = bootstrap_specifier;
2804 } else {
2805 assert(bootstrap_specifier->is_objArray(), "");
2806 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2807 int len = args->length();
2808 assert(len >= 1, "");
2809 bsm = Handle(THREAD, args->obj_at(0));
2810 if (len > 1) {
2811 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2812 for (int i = 1; i < len; i++)
2813 args1->obj_at_put(i-1, args->obj_at(i));
2814 info = Handle(THREAD, args1);
2815 }
2816 }
2817 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2818 "caller must supply a valid BSM");
2819
2820 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2821 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2822
2823 // This should not happen. JDK code should take care of that.
2824 if (caller == NULL || method_type.is_null()) {
2825 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2826 }
2827
2828 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2829 assert(appendix_box->obj_at(0) == NULL, "");
2830
2831 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2832 JavaCallArguments args;
2833 args.push_oop(Handle(THREAD, caller->java_mirror()));
2834 args.push_oop(bsm);
2835 args.push_oop(method_name);
2836 args.push_oop(method_type);
2837 args.push_oop(info);
2838 args.push_oop(appendix_box);
2839 JavaValue result(T_OBJECT);
2840 JavaCalls::call_static(&result,
2841 SystemDictionary::MethodHandleNatives_klass(),
2842 vmSymbols::linkCallSite_name(),
2843 vmSymbols::linkCallSite_signature(),
2844 &args, CHECK_(empty));
2845 Handle mname(THREAD, (oop) result.get_jobject());
2846 (*method_type_result) = method_type;
2847 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2848 }
2849
2850 // Since the identity hash code for symbols changes when the symbols are
2851 // moved from the regular perm gen (hash in the mark word) to the shared
2852 // spaces (hash is the address), the classes loaded into the dictionary
2853 // may be in the wrong buckets.
2854
2855 void SystemDictionary::reorder_dictionary() {
2856 dictionary()->reorder_dictionary();
2857 }
2858
2859
2860 void SystemDictionary::copy_buckets(char** top, char* end) {
2861 dictionary()->copy_buckets(top, end);
2862 }
2863
2864
2865 void SystemDictionary::copy_table(char** top, char* end) {
2866 dictionary()->copy_table(top, end);
2867 }
2868
2869 int SystemDictionary::number_of_classes() {
2870 return dictionary()->number_of_entries();
2871 }
2872
2873
2874 // ----------------------------------------------------------------------------
2875 void SystemDictionary::print_shared(bool details) {
2876 shared_dictionary()->print(details);
2877 }
2878
2879 void SystemDictionary::print(bool details) {
2880 dictionary()->print(details);
2881
2882 // Placeholders
2883 GCMutexLocker mu(SystemDictionary_lock);
2884 placeholders()->print();
2885
2886 // loader constraints - print under SD_lock
2887 constraints()->print();
2888 }
2889
2890
2891 void SystemDictionary::verify() {
2892 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2893 guarantee(constraints() != NULL,
2894 "Verify of loader constraints failed");
2895 guarantee(dictionary()->number_of_entries() >= 0 &&
2896 placeholders()->number_of_entries() >= 0,
2897 "Verify of system dictionary failed");
2898
2899 // Verify dictionary
2900 dictionary()->verify();
2901
2902 GCMutexLocker mu(SystemDictionary_lock);
2903 placeholders()->verify();
2904
2905 // Verify constraint table
2906 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2907 constraints()->verify(dictionary(), placeholders());
2908 }
2909
2910 // caller needs ResourceMark
2911 const char* SystemDictionary::loader_name(const oop loader) {
2912 return ((loader) == NULL ? "<bootloader>" :
2913 InstanceKlass::cast((loader)->klass())->name()->as_C_string());
2914 }
2915
2916 // caller needs ResourceMark
2917 const char* SystemDictionary::loader_name(const ClassLoaderData* loader_data) {
2918 return (loader_data->class_loader() == NULL ? "<bootloader>" :
2919 SystemDictionary::loader_name(loader_data->class_loader()));
2920 }