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