1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/symbolTable.hpp"
44 #include "classfile/systemDictionary.hpp"
45 #include "classfile/vmSymbols.hpp"
46 #include "code/codeCache.hpp"
47 #include "compiler/compileBroker.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/oopStorage.inline.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "interpreter/bytecodeStream.hpp"
52 #include "interpreter/interpreter.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "logging/log.hpp"
55 #include "logging/logStream.hpp"
56 #include "memory/filemap.hpp"
57 #include "memory/heapShared.hpp"
58 #include "memory/metaspaceClosure.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/access.inline.hpp"
63 #include "oops/instanceKlass.hpp"
64 #include "oops/instanceRefKlass.hpp"
65 #include "oops/klass.inline.hpp"
66 #include "oops/method.inline.hpp"
67 #include "oops/methodData.hpp"
68 #include "oops/objArrayKlass.hpp"
69 #include "oops/objArrayOop.inline.hpp"
70 #include "oops/oop.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #if INCLUDE_CDS
88 #include "classfile/systemDictionaryShared.hpp"
89 #endif
90 #if INCLUDE_JFR
91 #include "jfr/jfr.hpp"
92 #endif
93
94 PlaceholderTable* SystemDictionary::_placeholders = NULL;
95 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
96 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
97 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
98 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
99
100 oop SystemDictionary::_system_loader_lock_obj = NULL;
101
102 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
103 = { NULL /*, NULL...*/ };
104
105 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
106
107 oop SystemDictionary::_java_system_loader = NULL;
108 oop SystemDictionary::_java_platform_loader = NULL;
109
110 // Default ProtectionDomainCacheSize value
111
112 const int defaultProtectionDomainCacheSize = 1009;
113
114 ClassLoadInfo::ClassLoadInfo() {
115 _protection_domain = Handle();
116 _unsafe_anonymous_host = NULL;
117 _cp_patches = NULL;
118 _class_hidden_info._dynamic_nest_host = NULL;
119 _class_hidden_info._class_data = Handle();
120 _is_hidden = false;
121 _is_strong_hidden = false;
122 _can_access_vm_annotations = false;
123 }
124
125 ClassLoadInfo::ClassLoadInfo(Handle protection_domain) {
126 _protection_domain = protection_domain;
127 _unsafe_anonymous_host = NULL;
128 _cp_patches = NULL;
129 _class_hidden_info._dynamic_nest_host = NULL;
130 _class_hidden_info._class_data = Handle();
131 _is_hidden = false;
132 _is_strong_hidden = false;
133 _can_access_vm_annotations = false;
134 }
135
136 ClassLoadInfo::ClassLoadInfo(Handle protection_domain,
137 const InstanceKlass* unsafe_anonymous_host,
138 GrowableArray<Handle>* cp_patches,
139 InstanceKlass* dynamic_nest_host,
140 Handle class_data,
141 bool is_hidden,
142 bool is_strong_hidden,
143 bool can_access_vm_annotations) {
144 _protection_domain = protection_domain;
145 _unsafe_anonymous_host = unsafe_anonymous_host;
146 _cp_patches = cp_patches;
147 _class_hidden_info._dynamic_nest_host = dynamic_nest_host;
148 _class_hidden_info._class_data = class_data;
149 _is_hidden = is_hidden;
150 _is_strong_hidden = is_strong_hidden;
151 _can_access_vm_annotations = can_access_vm_annotations;
152 }
153
154 // ----------------------------------------------------------------------------
155 // Java-level SystemLoader and PlatformLoader
156
157 oop SystemDictionary::java_system_loader() {
158 return _java_system_loader;
159 }
160
161 oop SystemDictionary::java_platform_loader() {
162 return _java_platform_loader;
163 }
164
165 void SystemDictionary::compute_java_loaders(TRAPS) {
166 JavaValue result(T_OBJECT);
167 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
168 JavaCalls::call_static(&result,
169 class_loader_klass,
170 vmSymbols::getSystemClassLoader_name(),
171 vmSymbols::void_classloader_signature(),
172 CHECK);
173
174 _java_system_loader = (oop)result.get_jobject();
175
176 JavaCalls::call_static(&result,
177 class_loader_klass,
178 vmSymbols::getPlatformClassLoader_name(),
179 vmSymbols::void_classloader_signature(),
180 CHECK);
181
182 _java_platform_loader = (oop)result.get_jobject();
183 }
184
185 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
186 if (create_mirror_cld) {
187 // Add a new class loader data to the graph.
188 return ClassLoaderDataGraph::add(class_loader, true);
189 } else {
190 return (class_loader() == NULL) ? ClassLoaderData::the_null_class_loader_data() :
191 ClassLoaderDataGraph::find_or_create(class_loader);
192 }
193 }
194
195 // ----------------------------------------------------------------------------
196 // Parallel class loading check
197
198 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
199 if (class_loader.is_null()) return true;
200 if (AlwaysLockClassLoader) return false;
201 return java_lang_ClassLoader::parallelCapable(class_loader());
202 }
203 // ----------------------------------------------------------------------------
204 // ParallelDefineClass flag does not apply to bootclass loader
205 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
206 if (class_loader.is_null()) return false;
207 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
208 return true;
209 }
210 return false;
211 }
212
213 // Returns true if the passed class loader is the builtin application class loader
214 // or a custom system class loader. A customer system class loader can be
215 // specified via -Djava.system.class.loader.
216 bool SystemDictionary::is_system_class_loader(oop class_loader) {
217 if (class_loader == NULL) {
218 return false;
219 }
220 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
221 class_loader == _java_system_loader);
222 }
223
224 // Returns true if the passed class loader is the platform class loader.
225 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
226 if (class_loader == NULL) {
227 return false;
228 }
229 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
230 }
231
232 // ----------------------------------------------------------------------------
233 // Resolving of classes
234
235 // Forwards to resolve_or_null
236
237 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
238 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
239 if (HAS_PENDING_EXCEPTION || klass == NULL) {
240 // can return a null klass
241 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
242 }
243 return klass;
244 }
245
246 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
247 bool throw_error,
248 Klass* klass, TRAPS) {
249 if (HAS_PENDING_EXCEPTION) {
250 // If we have a pending exception we forward it to the caller, unless throw_error is true,
251 // in which case we have to check whether the pending exception is a ClassNotFoundException,
252 // and if so convert it to a NoClassDefFoundError
253 // And chain the original ClassNotFoundException
254 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
255 ResourceMark rm(THREAD);
256 assert(klass == NULL, "Should not have result with exception pending");
257 Handle e(THREAD, PENDING_EXCEPTION);
258 CLEAR_PENDING_EXCEPTION;
259 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
260 } else {
261 return NULL;
262 }
263 }
264 // Class not found, throw appropriate error or exception depending on value of throw_error
265 if (klass == NULL) {
266 ResourceMark rm(THREAD);
267 if (throw_error) {
268 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
269 } else {
270 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
271 }
272 }
273 return klass;
274 }
275
276
277 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
278 bool throw_error, TRAPS)
279 {
280 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
281 }
282
283
284 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
285
286 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
287 if (Signature::is_array(class_name)) {
288 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
289 } else {
290 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
291 }
292 }
293
294 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
295 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
296 Handle class_loader,
297 Handle protection_domain,
298 TRAPS) {
299 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
300 if (Signature::has_envelope(class_name)) {
301 ResourceMark rm(THREAD);
302 // Ignore wrapping L and ;.
303 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
304 class_name->utf8_length() - 2);
305 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
306 } else {
307 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
308 }
309 }
310
311 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
312 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
313 }
314
315 // Forwards to resolve_instance_class_or_null
316
317 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
318 Handle class_loader,
319 Handle protection_domain,
320 TRAPS) {
321 assert(Signature::is_array(class_name), "must be array");
322 ResourceMark rm(THREAD);
323 SignatureStream ss(class_name, false);
324 int ndims = ss.skip_array_prefix(); // skip all '['s
325 Klass* k = NULL;
326 BasicType t = ss.type();
327 if (ss.has_envelope()) {
328 Symbol* obj_class = ss.as_symbol();
329 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
330 class_loader,
331 protection_domain,
332 CHECK_NULL);
333 if (k != NULL) {
334 k = k->array_klass(ndims, CHECK_NULL);
335 }
336 } else {
337 k = Universe::typeArrayKlassObj(t);
338 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
339 }
340 return k;
341 }
342
343
344 // Must be called for any super-class or super-interface resolution
345 // during class definition to allow class circularity checking
346 // super-interface callers:
347 // parse_interfaces - for defineClass & jvmtiRedefineClasses
348 // super-class callers:
349 // ClassFileParser - for defineClass & jvmtiRedefineClasses
350 // load_shared_class - while loading a class from shared archive
351 // resolve_instance_class_or_null:
352 // via: handle_parallel_super_load
353 // when resolving a class that has an existing placeholder with
354 // a saved superclass [i.e. a defineClass is currently in progress]
355 // if another thread is trying to resolve the class, it must do
356 // super-class checks on its own thread to catch class circularity
357 // This last call is critical in class circularity checking for cases
358 // where classloading is delegated to different threads and the
359 // classloader lock is released.
360 // Take the case: Base->Super->Base
361 // 1. If thread T1 tries to do a defineClass of class Base
362 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
363 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
364 // so it tries to load Super
365 // 3. If we load the class internally, or user classloader uses same thread
366 // loadClassFromxxx or defineClass via parseClassFile Super ...
367 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
368 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
369 // 3.4 calls resolve_super_or_fail Base
370 // 3.5 finds T1,Base -> throws class circularity
371 //OR 4. If T2 tries to resolve Super via defineClass Super ...
372 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
373 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
374 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
375 // 4.4 finds T2, Super -> throws class circularity
376 // Must be called, even if superclass is null, since this is
377 // where the placeholder entry is created which claims this
378 // thread is loading this class/classloader.
379 // Be careful when modifying this code: once you have run
380 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
381 // you need to find_and_remove it before returning.
382 // So be careful to not exit with a CHECK_ macro betweeen these calls.
383 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
384 Symbol* super_name,
385 Handle class_loader,
386 Handle protection_domain,
387 bool is_superclass,
388 TRAPS) {
389 assert(!Signature::is_array(super_name), "invalid super class name");
390 #if INCLUDE_CDS
391 if (DumpSharedSpaces) {
392 // Special processing for handling UNREGISTERED shared classes.
393 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
394 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
395 if (k) {
396 return k;
397 }
398 }
399 #endif // INCLUDE_CDS
400
401 // Double-check, if child class is already loaded, just return super-class,interface
402 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
403 // dictionary.
404 // Make sure there's a placeholder for the *child* before resolving.
405 // Used as a claim that this thread is currently loading superclass/classloader
406 // Used here for ClassCircularity checks and also for heap verification
407 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
408 // Must check ClassCircularity before checking if super class is already loaded.
409 //
410 // We might not already have a placeholder if this child_name was
411 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
412 // the name of the class might not be known until the stream is actually
413 // parsed.
414 // Bugs 4643874, 4715493
415
416 ClassLoaderData* loader_data = class_loader_data(class_loader);
417 Dictionary* dictionary = loader_data->dictionary();
418 unsigned int d_hash = dictionary->compute_hash(child_name);
419 unsigned int p_hash = placeholders()->compute_hash(child_name);
420 int p_index = placeholders()->hash_to_index(p_hash);
421 // can't throw error holding a lock
422 bool child_already_loaded = false;
423 bool throw_circularity_error = false;
424 {
425 MutexLocker mu(THREAD, SystemDictionary_lock);
426 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
427 InstanceKlass* quicksuperk;
428 // to support // loading: if child done loading, just return superclass
429 // if super_name, & class_loader don't match:
430 // if initial define, SD update will give LinkageError
431 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
432 // so we don't throw an exception here.
433 // see: nsk redefclass014 & java.lang.instrument Instrument032
434 if ((childk != NULL ) && (is_superclass) &&
435 ((quicksuperk = childk->java_super()) != NULL) &&
436 ((quicksuperk->name() == super_name) &&
437 (quicksuperk->class_loader() == class_loader()))) {
438 return quicksuperk;
439 } else {
440 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
441 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
442 throw_circularity_error = true;
443 }
444 }
445 if (!throw_circularity_error) {
446 // Be careful not to exit resolve_super
447 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
448 }
449 }
450 if (throw_circularity_error) {
451 ResourceMark rm(THREAD);
452 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
453 }
454
455 // java.lang.Object should have been found above
456 assert(super_name != NULL, "null super class for resolving");
457 // Resolve the super class or interface, check results on return
458 InstanceKlass* superk =
459 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
460 class_loader,
461 protection_domain,
462 THREAD);
463
464 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
465 // It is no longer necessary to keep the placeholder table alive until update_dictionary
466 // or error. GC used to walk the placeholder table as strong roots.
467 // The instanceKlass is kept alive because the class loader is on the stack,
468 // which keeps the loader_data alive, as well as all instanceKlasses in
469 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
470 {
471 MutexLocker mu(THREAD, SystemDictionary_lock);
472 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
473 SystemDictionary_lock->notify_all();
474 }
475 if (HAS_PENDING_EXCEPTION || superk == NULL) {
476 // can null superk
477 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
478 assert(k == NULL || k == superk, "must be");
479 if (k == NULL) {
480 superk = NULL;
481 }
482 }
483
484 return superk;
485 }
486
487 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
488 Handle class_loader,
489 Handle protection_domain,
490 TRAPS) {
491 // Now we have to call back to java to check if the initating class has access
492 JavaValue result(T_VOID);
493 LogTarget(Debug, protectiondomain) lt;
494 if (lt.is_enabled()) {
495 ResourceMark rm(THREAD);
496 // Print out trace information
497 LogStream ls(lt);
498 ls.print_cr("Checking package access");
499 if (class_loader() != NULL) {
500 ls.print("class loader: ");
501 class_loader()->print_value_on(&ls);
502 } else {
503 ls.print_cr("class loader: NULL");
504 }
505 if (protection_domain() != NULL) {
506 ls.print(" protection domain: ");
507 protection_domain()->print_value_on(&ls);
508 } else {
509 ls.print_cr(" protection domain: NULL");
510 }
511 ls.print(" loading: "); klass->print_value_on(&ls);
512 ls.cr();
513 }
514
515 // This handle and the class_loader handle passed in keeps this class from
516 // being unloaded through several GC points.
517 // The class_loader handle passed in is the initiating loader.
518 Handle mirror(THREAD, klass->java_mirror());
519
520 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
521 JavaCalls::call_special(&result,
522 class_loader,
523 system_loader,
524 vmSymbols::checkPackageAccess_name(),
525 vmSymbols::class_protectiondomain_signature(),
526 mirror,
527 protection_domain,
528 THREAD);
529
530 if (HAS_PENDING_EXCEPTION) {
531 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
532 } else {
533 log_debug(protectiondomain)("granted");
534 }
535
536 if (HAS_PENDING_EXCEPTION) return;
537
538 // If no exception has been thrown, we have validated the protection domain
539 // Insert the protection domain of the initiating class into the set.
540 {
541 ClassLoaderData* loader_data = class_loader_data(class_loader);
542 Dictionary* dictionary = loader_data->dictionary();
543
544 Symbol* kn = klass->name();
545 unsigned int d_hash = dictionary->compute_hash(kn);
546
547 MutexLocker mu(THREAD, SystemDictionary_lock);
548 int d_index = dictionary->hash_to_index(d_hash);
549 dictionary->add_protection_domain(d_index, d_hash, klass,
550 protection_domain, THREAD);
551 }
552 }
553
554 // We only get here if this thread finds that another thread
555 // has already claimed the placeholder token for the current operation,
556 // but that other thread either never owned or gave up the
557 // object lock
558 // Waits on SystemDictionary_lock to indicate placeholder table updated
559 // On return, caller must recheck placeholder table state
560 //
561 // We only get here if
562 // 1) custom classLoader, i.e. not bootstrap classloader
563 // 2) custom classLoader has broken the class loader objectLock
564 // so another thread got here in parallel
565 //
566 // lockObject must be held.
567 // Complicated dance due to lock ordering:
568 // Must first release the classloader object lock to
569 // allow initial definer to complete the class definition
570 // and to avoid deadlock
571 // Reclaim classloader lock object with same original recursion count
572 // Must release SystemDictionary_lock after notify, since
573 // class loader lock must be claimed before SystemDictionary_lock
574 // to prevent deadlocks
575 //
576 // The notify allows applications that did an untimed wait() on
577 // the classloader object lock to not hang.
578 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
579 assert_lock_strong(SystemDictionary_lock);
580
581 bool calledholdinglock
582 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
583 assert(calledholdinglock,"must hold lock for notify");
584 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
585 ObjectSynchronizer::notifyall(lockObject, THREAD);
586 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
587 SystemDictionary_lock->wait();
588 SystemDictionary_lock->unlock();
589 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
590 SystemDictionary_lock->lock();
591 }
592
593 // If the class in is in the placeholder table, class loading is in progress
594 // For cases where the application changes threads to load classes, it
595 // is critical to ClassCircularity detection that we try loading
596 // the superclass on the same thread internally, so we do parallel
597 // super class loading here.
598 // This also is critical in cases where the original thread gets stalled
599 // even in non-circularity situations.
600 // Note: must call resolve_super_or_fail even if null super -
601 // to force placeholder entry creation for this class for circularity detection
602 // Caller must check for pending exception
603 // Returns non-null Klass* if other thread has completed load
604 // and we are done,
605 // If return null Klass* and no pending exception, the caller must load the class
606 InstanceKlass* SystemDictionary::handle_parallel_super_load(
607 Symbol* name, Symbol* superclassname, Handle class_loader,
608 Handle protection_domain, Handle lockObject, TRAPS) {
609
610 ClassLoaderData* loader_data = class_loader_data(class_loader);
611 Dictionary* dictionary = loader_data->dictionary();
612 unsigned int d_hash = dictionary->compute_hash(name);
613 unsigned int p_hash = placeholders()->compute_hash(name);
614 int p_index = placeholders()->hash_to_index(p_hash);
615
616 // superk is not used, resolve_super called for circularity check only
617 // This code is reached in two situations. One if this thread
618 // is loading the same class twice (e.g. ClassCircularity, or
619 // java.lang.instrument).
620 // The second is if another thread started the resolve_super first
621 // and has not yet finished.
622 // In both cases the original caller will clean up the placeholder
623 // entry on error.
624 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
625 superclassname,
626 class_loader,
627 protection_domain,
628 true,
629 CHECK_NULL);
630
631 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
632 // Serial class loaders and bootstrap classloader do wait for superclass loads
633 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
634 MutexLocker mu(THREAD, SystemDictionary_lock);
635 // Check if classloading completed while we were loading superclass or waiting
636 return find_class(d_hash, name, dictionary);
637 }
638
639 // must loop to both handle other placeholder updates
640 // and spurious notifications
641 bool super_load_in_progress = true;
642 PlaceholderEntry* placeholder;
643 while (super_load_in_progress) {
644 MutexLocker mu(THREAD, SystemDictionary_lock);
645 // Check if classloading completed while we were loading superclass or waiting
646 InstanceKlass* check = find_class(d_hash, name, dictionary);
647 if (check != NULL) {
648 // Klass is already loaded, so just return it
649 return check;
650 } else {
651 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
652 if (placeholder && placeholder->super_load_in_progress() ){
653 // We only get here if the application has released the
654 // classloader lock when another thread was in the middle of loading a
655 // superclass/superinterface for this class, and now
656 // this thread is also trying to load this class.
657 // To minimize surprises, the first thread that started to
658 // load a class should be the one to complete the loading
659 // with the classfile it initially expected.
660 // This logic has the current thread wait once it has done
661 // all the superclass/superinterface loading it can, until
662 // the original thread completes the class loading or fails
663 // If it completes we will use the resulting InstanceKlass
664 // which we will find below in the systemDictionary.
665 // We also get here for parallel bootstrap classloader
666 if (class_loader.is_null()) {
667 SystemDictionary_lock->wait();
668 } else {
669 double_lock_wait(lockObject, THREAD);
670 }
671 } else {
672 // If not in SD and not in PH, other thread's load must have failed
673 super_load_in_progress = false;
674 }
675 }
676 }
677 return NULL;
678 }
679
680 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
681 assert(event != NULL, "invariant");
682 assert(k != NULL, "invariant");
683 assert(event->should_commit(), "invariant");
684 event->set_loadedClass(k);
685 event->set_definingClassLoader(k->class_loader_data());
686 event->set_initiatingClassLoader(init_cld);
687 event->commit();
688 }
689
690
691 // Be careful when modifying this code: once you have run
692 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
693 // you need to find_and_remove it before returning.
694 // So be careful to not exit with a CHECK_ macro betweeen these calls.
695 //
696 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
697 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
698 Handle class_loader,
699 Handle protection_domain,
700 TRAPS) {
701 assert(name != NULL && !Signature::is_array(name) &&
702 !Signature::has_envelope(name), "invalid class name");
703
704 EventClassLoad class_load_start_event;
705
706 HandleMark hm(THREAD);
707
708 // Fix for 4474172; see evaluation for more details
709 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
710 ClassLoaderData* loader_data = register_loader(class_loader);
711 Dictionary* dictionary = loader_data->dictionary();
712 unsigned int d_hash = dictionary->compute_hash(name);
713
714 // Do lookup to see if class already exist and the protection domain
715 // has the right access
716 // This call uses find which checks protection domain already matches
717 // All subsequent calls use find_class, and set has_loaded_class so that
718 // before we return a result we call out to java to check for valid protection domain
719 // to allow returning the Klass* and add it to the pd_set if it is valid
720 {
721 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
722 if (probe != NULL) return probe;
723 }
724
725 // Non-bootstrap class loaders will call out to class loader and
726 // define via jvm/jni_DefineClass which will acquire the
727 // class loader object lock to protect against multiple threads
728 // defining the class in parallel by accident.
729 // This lock must be acquired here so the waiter will find
730 // any successful result in the SystemDictionary and not attempt
731 // the define.
732 // ParallelCapable Classloaders and the bootstrap classloader
733 // do not acquire lock here.
734 bool DoObjectLock = true;
735 if (is_parallelCapable(class_loader)) {
736 DoObjectLock = false;
737 }
738
739 unsigned int p_hash = placeholders()->compute_hash(name);
740 int p_index = placeholders()->hash_to_index(p_hash);
741
742 // Class is not in SystemDictionary so we have to do loading.
743 // Make sure we are synchronized on the class loader before we proceed
744 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
745 check_loader_lock_contention(lockObject, THREAD);
746 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
747
748 // Check again (after locking) if class already exist in SystemDictionary
749 bool class_has_been_loaded = false;
750 bool super_load_in_progress = false;
751 bool havesupername = false;
752 InstanceKlass* k = NULL;
753 PlaceholderEntry* placeholder;
754 Symbol* superclassname = NULL;
755
756 assert(THREAD->can_call_java(),
757 "can not load classes with compiler thread: class=%s, classloader=%s",
758 name->as_C_string(),
759 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
760 {
761 MutexLocker mu(THREAD, SystemDictionary_lock);
762 InstanceKlass* check = find_class(d_hash, name, dictionary);
763 if (check != NULL) {
764 // InstanceKlass is already loaded, so just return it
765 class_has_been_loaded = true;
766 k = check;
767 } else {
768 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
769 if (placeholder && placeholder->super_load_in_progress()) {
770 super_load_in_progress = true;
771 if (placeholder->havesupername() == true) {
772 superclassname = placeholder->supername();
773 havesupername = true;
774 }
775 }
776 }
777 }
778
779 // If the class is in the placeholder table, class loading is in progress
780 if (super_load_in_progress && havesupername==true) {
781 k = handle_parallel_super_load(name,
782 superclassname,
783 class_loader,
784 protection_domain,
785 lockObject, THREAD);
786 if (HAS_PENDING_EXCEPTION) {
787 return NULL;
788 }
789 if (k != NULL) {
790 class_has_been_loaded = true;
791 }
792 }
793
794 bool throw_circularity_error = false;
795 if (!class_has_been_loaded) {
796 bool load_instance_added = false;
797
798 // add placeholder entry to record loading instance class
799 // Five cases:
800 // All cases need to prevent modifying bootclasssearchpath
801 // in parallel with a classload of same classname
802 // Redefineclasses uses existence of the placeholder for the duration
803 // of the class load to prevent concurrent redefinition of not completely
804 // defined classes.
805 // case 1. traditional classloaders that rely on the classloader object lock
806 // - no other need for LOAD_INSTANCE
807 // case 2. traditional classloaders that break the classloader object lock
808 // as a deadlock workaround. Detection of this case requires that
809 // this check is done while holding the classloader object lock,
810 // and that lock is still held when calling classloader's loadClass.
811 // For these classloaders, we ensure that the first requestor
812 // completes the load and other requestors wait for completion.
813 // case 3. Bootstrap classloader - don't own objectLocker
814 // This classloader supports parallelism at the classloader level,
815 // but only allows a single load of a class/classloader pair.
816 // No performance benefit and no deadlock issues.
817 // case 4. parallelCapable user level classloaders - without objectLocker
818 // Allow parallel classloading of a class/classloader pair
819
820 {
821 MutexLocker mu(THREAD, SystemDictionary_lock);
822 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
823 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
824 if (oldprobe) {
825 // only need check_seen_thread once, not on each loop
826 // 6341374 java/lang/Instrument with -Xcomp
827 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
828 throw_circularity_error = true;
829 } else {
830 // case 1: traditional: should never see load_in_progress.
831 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
832
833 // case 3: bootstrap classloader: prevent futile classloading,
834 // wait on first requestor
835 if (class_loader.is_null()) {
836 SystemDictionary_lock->wait();
837 } else {
838 // case 2: traditional with broken classloader lock. wait on first
839 // requestor.
840 double_lock_wait(lockObject, THREAD);
841 }
842 // Check if classloading completed while we were waiting
843 InstanceKlass* check = find_class(d_hash, name, dictionary);
844 if (check != NULL) {
845 // Klass is already loaded, so just return it
846 k = check;
847 class_has_been_loaded = true;
848 }
849 // check if other thread failed to load and cleaned up
850 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
851 }
852 }
853 }
854 }
855 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
856 // case 4: parallelCapable: allow competing threads to try
857 // LOAD_INSTANCE in parallel
858
859 if (!throw_circularity_error && !class_has_been_loaded) {
860 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
861 load_instance_added = true;
862 // For class loaders that do not acquire the classloader object lock,
863 // if they did not catch another thread holding LOAD_INSTANCE,
864 // need a check analogous to the acquire ObjectLocker/find_class
865 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
866 // one final check if the load has already completed
867 // class loaders holding the ObjectLock shouldn't find the class here
868 InstanceKlass* check = find_class(d_hash, name, dictionary);
869 if (check != NULL) {
870 // Klass is already loaded, so return it after checking/adding protection domain
871 k = check;
872 class_has_been_loaded = true;
873 }
874 }
875 }
876
877 // must throw error outside of owning lock
878 if (throw_circularity_error) {
879 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
880 ResourceMark rm(THREAD);
881 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
882 }
883
884 if (!class_has_been_loaded) {
885
886 // Do actual loading
887 k = load_instance_class(name, class_loader, THREAD);
888
889 // If everything was OK (no exceptions, no null return value), and
890 // class_loader is NOT the defining loader, do a little more bookkeeping.
891 if (!HAS_PENDING_EXCEPTION && k != NULL &&
892 k->class_loader() != class_loader()) {
893
894 check_constraints(d_hash, k, class_loader, false, THREAD);
895
896 // Need to check for a PENDING_EXCEPTION again; check_constraints
897 // can throw but we may have to remove entry from the placeholder table below.
898 if (!HAS_PENDING_EXCEPTION) {
899 // Record dependency for non-parent delegation.
900 // This recording keeps the defining class loader of the klass (k) found
901 // from being unloaded while the initiating class loader is loaded
902 // even if the reference to the defining class loader is dropped
903 // before references to the initiating class loader.
904 loader_data->record_dependency(k);
905
906 { // Grabbing the Compile_lock prevents systemDictionary updates
907 // during compilations.
908 MutexLocker mu(THREAD, Compile_lock);
909 update_dictionary(d_hash, p_index, p_hash,
910 k, class_loader, THREAD);
911 }
912
913 if (JvmtiExport::should_post_class_load()) {
914 Thread *thread = THREAD;
915 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
916 JvmtiExport::post_class_load((JavaThread *) thread, k);
917 }
918 }
919 }
920 } // load_instance_class
921
922 if (load_instance_added == true) {
923 // clean up placeholder entries for LOAD_INSTANCE success or error
924 // This brackets the SystemDictionary updates for both defining
925 // and initiating loaders
926 MutexLocker mu(THREAD, SystemDictionary_lock);
927 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
928 SystemDictionary_lock->notify_all();
929 }
930 }
931
932 if (HAS_PENDING_EXCEPTION || k == NULL) {
933 return NULL;
934 }
935 if (class_load_start_event.should_commit()) {
936 post_class_load_event(&class_load_start_event, k, loader_data);
937 }
938 #ifdef ASSERT
939 {
940 ClassLoaderData* loader_data = k->class_loader_data();
941 MutexLocker mu(THREAD, SystemDictionary_lock);
942 InstanceKlass* kk = find_class(name, loader_data);
943 assert(kk == k, "should be present in dictionary");
944 }
945 #endif
946
947 // return if the protection domain in NULL
948 if (protection_domain() == NULL) return k;
949
950 // Check the protection domain has the right access
951 if (dictionary->is_valid_protection_domain(d_hash, name,
952 protection_domain)) {
953 return k;
954 }
955
956 // Verify protection domain. If it fails an exception is thrown
957 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
958
959 return k;
960 }
961
962
963 // This routine does not lock the system dictionary.
964 //
965 // Since readers don't hold a lock, we must make sure that system
966 // dictionary entries are only removed at a safepoint (when only one
967 // thread is running), and are added to in a safe way (all links must
968 // be updated in an MT-safe manner).
969 //
970 // Callers should be aware that an entry could be added just after
971 // _dictionary->bucket(index) is read here, so the caller will not see
972 // the new entry.
973
974 Klass* SystemDictionary::find(Symbol* class_name,
975 Handle class_loader,
976 Handle protection_domain,
977 TRAPS) {
978
979 // The result of this call should be consistent with the result
980 // of the call to resolve_instance_class_or_null().
981 // See evaluation 6790209 and 4474172 for more details.
982 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
983 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
984
985 if (loader_data == NULL) {
986 // If the ClassLoaderData has not been setup,
987 // then the class loader has no entries in the dictionary.
988 return NULL;
989 }
990
991 Dictionary* dictionary = loader_data->dictionary();
992 unsigned int d_hash = dictionary->compute_hash(class_name);
993 return dictionary->find(d_hash, class_name,
994 protection_domain);
995 }
996
997
998 // Look for a loaded instance or array klass by name. Do not do any loading.
999 // return NULL in case of error.
1000 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1001 Handle class_loader,
1002 Handle protection_domain,
1003 TRAPS) {
1004 Klass* k = NULL;
1005 assert(class_name != NULL, "class name must be non NULL");
1006
1007 if (Signature::is_array(class_name)) {
1008 // The name refers to an array. Parse the name.
1009 // dimension and object_key in FieldArrayInfo are assigned as a
1010 // side-effect of this call
1011 SignatureStream ss(class_name, false);
1012 int ndims = ss.skip_array_prefix(); // skip all '['s
1013 BasicType t = ss.type();
1014 if (t != T_OBJECT) {
1015 k = Universe::typeArrayKlassObj(t);
1016 } else {
1017 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
1018 }
1019 if (k != NULL) {
1020 k = k->array_klass_or_null(ndims);
1021 }
1022 } else {
1023 k = find(class_name, class_loader, protection_domain, THREAD);
1024 }
1025 return k;
1026 }
1027
1028 // Note: this method is much like resolve_from_stream, but
1029 // does not publish the classes via the SystemDictionary.
1030 // Handles Lookup.defineClass hidden, unsafe_DefineAnonymousClass
1031 // and redefineclasses. RedefinedClasses do not add to the class hierarchy.
1032 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1033 Handle class_loader,
1034 ClassFileStream* st,
1035 const ClassLoadInfo& cl_info,
1036 TRAPS) {
1037
1038 EventClassLoad class_load_start_event;
1039 ClassLoaderData* loader_data;
1040 bool is_unsafe_anon_class = cl_info.unsafe_anonymous_host() != NULL;
1041
1042 // - for unsafe anonymous class: create a new CLD whith a class holder that uses
1043 // the same class loader as the unsafe_anonymous_host.
1044 // - for hidden classes that are not strong: create a new CLD that has a class holder and
1045 // whose loader is the Lookup class's loader.
1046 // - for hidden class: add the class to the Lookup class's loader's CLD.
1047 if (is_unsafe_anon_class || cl_info.is_hidden()) {
1048 guarantee(!is_unsafe_anon_class || cl_info.unsafe_anonymous_host()->class_loader() == class_loader(),
1049 "should be NULL or the same");
1050 bool create_mirror_cld = is_unsafe_anon_class || !cl_info.is_strong_hidden();
1051 loader_data = register_loader(class_loader, create_mirror_cld);
1052 } else {
1053 loader_data = ClassLoaderData::class_loader_data(class_loader());
1054 }
1055
1056 assert(st != NULL, "invariant");
1057 assert(st->need_verify(), "invariant");
1058
1059 // Parse stream and create a klass.
1060 // Note that we do this even though this klass might
1061 // already be present in the SystemDictionary, otherwise we would not
1062 // throw potential ClassFormatErrors.
1063
1064 InstanceKlass* k = KlassFactory::create_from_stream(st,
1065 class_name,
1066 loader_data,
1067 cl_info,
1068 CHECK_NULL);
1069
1070 if ((cl_info.is_hidden() || is_unsafe_anon_class) && k != NULL) {
1071 // Hidden classes that are not strong and unsafe anonymous classes must update
1072 // ClassLoaderData holder so that they can be unloaded when the mirror is no
1073 // longer referenced.
1074 if (!cl_info.is_strong_hidden() || is_unsafe_anon_class) {
1075 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1076 }
1077
1078 {
1079 MutexLocker mu_r(THREAD, Compile_lock);
1080
1081 // Add to class hierarchy, initialize vtables, and do possible
1082 // deoptimizations.
1083 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1084 // But, do not add to dictionary.
1085 }
1086
1087 // Rewrite and patch constant pool here.
1088 k->link_class(CHECK_NULL);
1089 if (cl_info.cp_patches() != NULL) {
1090 k->constants()->patch_resolved_references(cl_info.cp_patches());
1091 }
1092
1093 // If it's anonymous, initialize it now, since nobody else will.
1094 if (is_unsafe_anon_class) {
1095 k->eager_initialize(CHECK_NULL);
1096 }
1097
1098 // notify jvmti
1099 if (JvmtiExport::should_post_class_load()) {
1100 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1101 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1102 }
1103 if (class_load_start_event.should_commit()) {
1104 post_class_load_event(&class_load_start_event, k, loader_data);
1105 }
1106 }
1107 assert(is_unsafe_anon_class || NULL == cl_info.cp_patches(),
1108 "cp_patches only found with unsafe_anonymous_host");
1109
1110 return k;
1111 }
1112
1113 // Add a klass to the system from a stream (called by jni_DefineClass and
1114 // JVM_DefineClass).
1115 // Note: class_name can be NULL. In that case we do not know the name of
1116 // the class until we have parsed the stream.
1117
1118 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1119 Handle class_loader,
1120 Handle protection_domain,
1121 ClassFileStream* st,
1122 TRAPS) {
1123
1124 HandleMark hm(THREAD);
1125
1126 // Classloaders that support parallelism, e.g. bootstrap classloader,
1127 // do not acquire lock here
1128 bool DoObjectLock = true;
1129 if (is_parallelCapable(class_loader)) {
1130 DoObjectLock = false;
1131 }
1132
1133 ClassLoaderData* loader_data = register_loader(class_loader);
1134
1135 // Make sure we are synchronized on the class loader before we proceed
1136 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1137 check_loader_lock_contention(lockObject, THREAD);
1138 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1139
1140 assert(st != NULL, "invariant");
1141
1142 // Parse the stream and create a klass.
1143 // Note that we do this even though this klass might
1144 // already be present in the SystemDictionary, otherwise we would not
1145 // throw potential ClassFormatErrors.
1146 InstanceKlass* k = NULL;
1147
1148 #if INCLUDE_CDS
1149 if (!DumpSharedSpaces) {
1150 k = SystemDictionaryShared::lookup_from_stream(class_name,
1151 class_loader,
1152 protection_domain,
1153 st,
1154 CHECK_NULL);
1155 }
1156 #endif
1157
1158 if (k == NULL) {
1159 if (st->buffer() == NULL) {
1160 return NULL;
1161 }
1162 ClassLoadInfo cl_info(protection_domain);
1163 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
1164 }
1165
1166 assert(k != NULL, "no klass created");
1167 Symbol* h_name = k->name();
1168 assert(class_name == NULL || class_name == h_name, "name mismatch");
1169
1170 // Add class just loaded
1171 // If a class loader supports parallel classloading handle parallel define requests
1172 // find_or_define_instance_class may return a different InstanceKlass
1173 if (is_parallelCapable(class_loader)) {
1174 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1175 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1176 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1177 assert(defined_k != NULL, "Should have a klass if there's no exception");
1178 loader_data->add_to_deallocate_list(k);
1179 k = defined_k;
1180 }
1181 } else {
1182 define_instance_class(k, THREAD);
1183 }
1184
1185 // If defining the class throws an exception register 'k' for cleanup.
1186 if (HAS_PENDING_EXCEPTION) {
1187 assert(k != NULL, "Must have an instance klass here!");
1188 loader_data->add_to_deallocate_list(k);
1189 return NULL;
1190 }
1191
1192 // Make sure we have an entry in the SystemDictionary on success
1193 debug_only( {
1194 MutexLocker mu(THREAD, SystemDictionary_lock);
1195
1196 Klass* check = find_class(h_name, k->class_loader_data());
1197 assert(check == k, "should be present in the dictionary");
1198 } );
1199
1200 return k;
1201 }
1202
1203 #if INCLUDE_CDS
1204 // Load a class for boot loader from the shared spaces. This also
1205 // forces the super class and all interfaces to be loaded.
1206 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1207 PackageEntry* pkg_entry,
1208 TRAPS) {
1209 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1210 if (ik != NULL && ik->is_shared_boot_class()) {
1211 return load_shared_class(ik, Handle(), Handle(), NULL, pkg_entry, THREAD);
1212 }
1213 return NULL;
1214 }
1215
1216 // Check if a shared class can be loaded by the specific classloader:
1217 //
1218 // NULL classloader:
1219 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1220 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1221 // be defined in an unnamed module.
1222 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1223 InstanceKlass* ik,
1224 PackageEntry* pkg_entry,
1225 Handle class_loader, TRAPS) {
1226 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1227 "Cannot use sharing if java.base is patched");
1228 ResourceMark rm(THREAD);
1229 int path_index = ik->shared_classpath_index();
1230 ClassLoaderData* loader_data = class_loader_data(class_loader);
1231 if (path_index < 0) {
1232 // path_index < 0 indicates that the class is intended for a custom loader
1233 // and should not be loaded by boot/platform/app loaders
1234 if (loader_data->is_builtin_class_loader_data()) {
1235 return false;
1236 } else {
1237 return true;
1238 }
1239 }
1240 SharedClassPathEntry* ent =
1241 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1242 if (!Universe::is_module_initialized()) {
1243 assert(ent != NULL && ent->is_modules_image(),
1244 "Loading non-bootstrap classes before the module system is initialized");
1245 assert(class_loader.is_null(), "sanity");
1246 return true;
1247 }
1248 // Get the pkg_entry from the classloader
1249 ModuleEntry* mod_entry = NULL;
1250 TempNewSymbol pkg_name = pkg_entry != NULL ? pkg_entry->name() :
1251 ClassLoader::package_from_class_name(class_name);
1252 if (pkg_name != NULL) {
1253 if (loader_data != NULL) {
1254 if (pkg_entry != NULL) {
1255 mod_entry = pkg_entry->module();
1256 // If the archived class is from a module that has been patched at runtime,
1257 // the class cannot be loaded from the archive.
1258 if (mod_entry != NULL && mod_entry->is_patched()) {
1259 return false;
1260 }
1261 }
1262 }
1263 }
1264
1265 if (class_loader.is_null()) {
1266 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1267 // The NULL classloader can load archived class originated from the
1268 // "modules" jimage and the -Xbootclasspath/a. For class from the
1269 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1270 // by the NULL classloader.
1271 if (mod_entry != NULL) {
1272 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1273 // ModuleEntry's location agrees with the archived class' origination.
1274 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1275 return true; // Module class from the "module" jimage
1276 }
1277 }
1278
1279 // If the archived class is not from the "module" jimage, the class can be
1280 // loaded by the NULL classloader if
1281 //
1282 // 1. the class is from the unamed package
1283 // 2. or, the class is not from a module defined in the NULL classloader
1284 // 3. or, the class is from an unamed module
1285 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1286 // the class is from the -Xbootclasspath/a
1287 if (pkg_name == NULL ||
1288 pkg_entry == NULL ||
1289 pkg_entry->in_unnamed_module()) {
1290 assert(mod_entry == NULL ||
1291 mod_entry == loader_data->unnamed_module(),
1292 "the unnamed module is not defined in the classloader");
1293 return true;
1294 }
1295 }
1296 return false;
1297 } else {
1298 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1299 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1300 return res;
1301 }
1302 }
1303
1304 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1305 Handle class_loader, Handle protection_domain,
1306 bool is_superclass, TRAPS) {
1307 assert(super_type->is_shared(), "must be");
1308
1309 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1310 class_loader, protection_domain, is_superclass, CHECK_0);
1311 if (found == super_type) {
1312 return true;
1313 } else {
1314 // The dynamically resolved super type is not the same as the one we used during dump time,
1315 // so we cannot use the child class.
1316 return false;
1317 }
1318 }
1319
1320 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1321 Handle protection_domain, TRAPS) {
1322 // Check the superclass and interfaces. They must be the same
1323 // as in dump time, because the layout of <ik> depends on
1324 // the specific layout of ik->super() and ik->local_interfaces().
1325 //
1326 // If unexpected superclass or interfaces are found, we cannot
1327 // load <ik> from the shared archive.
1328
1329 if (ik->super() != NULL &&
1330 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1331 class_loader, protection_domain, true, THREAD)) {
1332 return false;
1333 }
1334
1335 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1336 int num_interfaces = interfaces->length();
1337 for (int index = 0; index < num_interfaces; index++) {
1338 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1339 return false;
1340 }
1341 }
1342
1343 return true;
1344 }
1345
1346 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1347 Handle class_loader,
1348 Handle protection_domain,
1349 const ClassFileStream *cfs,
1350 PackageEntry* pkg_entry,
1351 TRAPS) {
1352 assert(ik != NULL, "sanity");
1353 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1354 Symbol* class_name = ik->name();
1355
1356 bool visible = is_shared_class_visible(
1357 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1358 if (!visible) {
1359 return NULL;
1360 }
1361
1362 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1363 return NULL;
1364 }
1365
1366 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1367 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1368 if (new_ik != NULL) {
1369 // The class is changed by CFLH. Return the new class. The shared class is
1370 // not used.
1371 return new_ik;
1372 }
1373
1374 // Adjust methods to recover missing data. They need addresses for
1375 // interpreter entry points and their default native method address
1376 // must be reset.
1377
1378 // Updating methods must be done under a lock so multiple
1379 // threads don't update these in parallel
1380 //
1381 // Shared classes are all currently loaded by either the bootstrap or
1382 // internal parallel class loaders, so this will never cause a deadlock
1383 // on a custom class loader lock.
1384
1385 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1386 {
1387 HandleMark hm(THREAD);
1388 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1389 check_loader_lock_contention(lockObject, THREAD);
1390 ObjectLocker ol(lockObject, THREAD, true);
1391 // prohibited package check assumes all classes loaded from archive call
1392 // restore_unshareable_info which calls ik->set_package()
1393 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1394 }
1395
1396 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1397 return ik;
1398 }
1399
1400 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1401 ik->print_class_load_logging(loader_data, NULL, NULL);
1402
1403 // For boot loader, ensure that GetSystemPackage knows that a class in this
1404 // package was loaded.
1405 if (loader_data->is_the_null_class_loader_data()) {
1406 int path_index = ik->shared_classpath_index();
1407 ik->set_classpath_index(path_index, THREAD);
1408 }
1409
1410 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1411 // Only dump the classes that can be stored into CDS archive
1412 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1413 ResourceMark rm(THREAD);
1414 classlist_file->print_cr("%s", ik->name()->as_C_string());
1415 classlist_file->flush();
1416 }
1417 }
1418
1419 // notify a class loaded from shared object
1420 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1421
1422 ik->set_has_passed_fingerprint_check(false);
1423 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1424 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1425 uint64_t cds_fp = ik->get_stored_fingerprint();
1426 if (aot_fp != 0 && aot_fp == cds_fp) {
1427 // This class matches with a class saved in an AOT library
1428 ik->set_has_passed_fingerprint_check(true);
1429 } else {
1430 if (log_is_enabled(Info, class, fingerprint)) {
1431 ResourceMark rm(THREAD);
1432 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1433 }
1434 }
1435 }
1436 }
1437
1438 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1439 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1440 assert(klass->is_shared(), "Must be shared class");
1441 if (klass->class_loader_data() != NULL) {
1442 return;
1443 }
1444
1445 // add super and interfaces first
1446 Klass* super = klass->super();
1447 if (super != NULL && super->class_loader_data() == NULL) {
1448 assert(super->is_instance_klass(), "Super should be instance klass");
1449 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1450 }
1451
1452 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1453 for (int i = 0; i < ifs->length(); i++) {
1454 InstanceKlass* ik = ifs->at(i);
1455 if (ik->class_loader_data() == NULL) {
1456 quick_resolve(ik, loader_data, domain, CHECK);
1457 }
1458 }
1459
1460 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1461 load_shared_class_misc(klass, loader_data, CHECK);
1462 Dictionary* dictionary = loader_data->dictionary();
1463 unsigned int hash = dictionary->compute_hash(klass->name());
1464 dictionary->add_klass(hash, klass->name(), klass);
1465 add_to_hierarchy(klass, CHECK);
1466 assert(klass->is_loaded(), "Must be in at least loaded state");
1467 }
1468 #endif // INCLUDE_CDS
1469
1470 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1471
1472 if (class_loader.is_null()) {
1473 ResourceMark rm(THREAD);
1474 PackageEntry* pkg_entry = NULL;
1475 bool search_only_bootloader_append = false;
1476 ClassLoaderData *loader_data = class_loader_data(class_loader);
1477
1478 // Find the package in the boot loader's package entry table.
1479 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1480 if (pkg_name != NULL) {
1481 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1482 }
1483
1484 // Prior to attempting to load the class, enforce the boot loader's
1485 // visibility boundaries.
1486 if (!Universe::is_module_initialized()) {
1487 // During bootstrapping, prior to module initialization, any
1488 // class attempting to be loaded must be checked against the
1489 // java.base packages in the boot loader's PackageEntryTable.
1490 // No class outside of java.base is allowed to be loaded during
1491 // this bootstrapping window.
1492 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1493 // Class is either in the unnamed package or in
1494 // a named package within the unnamed module. Either
1495 // case is outside of java.base, do not attempt to
1496 // load the class post java.base definition. If
1497 // java.base has not been defined, let the class load
1498 // and its package will be checked later by
1499 // ModuleEntryTable::verify_javabase_packages.
1500 if (ModuleEntryTable::javabase_defined()) {
1501 return NULL;
1502 }
1503 } else {
1504 // Check that the class' package is defined within java.base.
1505 ModuleEntry* mod_entry = pkg_entry->module();
1506 Symbol* mod_entry_name = mod_entry->name();
1507 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1508 return NULL;
1509 }
1510 }
1511 } else {
1512 // After the module system has been initialized, check if the class'
1513 // package is in a module defined to the boot loader.
1514 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1515 // Class is either in the unnamed package, in a named package
1516 // within a module not defined to the boot loader or in a
1517 // a named package within the unnamed module. In all cases,
1518 // limit visibility to search for the class only in the boot
1519 // loader's append path.
1520 if (!ClassLoader::has_bootclasspath_append()) {
1521 // If there is no bootclasspath append entry, no need to continue
1522 // searching.
1523 return NULL;
1524 }
1525 search_only_bootloader_append = true;
1526 }
1527 }
1528
1529 // Prior to bootstrapping's module initialization, never load a class outside
1530 // of the boot loader's module path
1531 assert(Universe::is_module_initialized() ||
1532 !search_only_bootloader_append,
1533 "Attempt to load a class outside of boot loader's module path");
1534
1535 // Search for classes in the CDS archive.
1536 InstanceKlass* k = NULL;
1537 {
1538 #if INCLUDE_CDS
1539 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1540 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1541 #endif
1542 }
1543
1544 if (k == NULL) {
1545 // Use VM class loader
1546 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1547 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1548 }
1549
1550 // find_or_define_instance_class may return a different InstanceKlass
1551 if (k != NULL) {
1552 InstanceKlass* defined_k =
1553 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1554 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1555 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1556 assert(defined_k != NULL, "Should have a klass if there's no exception");
1557 loader_data->add_to_deallocate_list(k);
1558 k = defined_k;
1559 } else if (HAS_PENDING_EXCEPTION) {
1560 loader_data->add_to_deallocate_list(k);
1561 return NULL;
1562 }
1563 }
1564 return k;
1565 } else {
1566 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1567 ResourceMark rm(THREAD);
1568
1569 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1570 JavaThread* jt = (JavaThread*) THREAD;
1571
1572 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1573 ClassLoader::perf_app_classload_selftime(),
1574 ClassLoader::perf_app_classload_count(),
1575 jt->get_thread_stat()->perf_recursion_counts_addr(),
1576 jt->get_thread_stat()->perf_timers_addr(),
1577 PerfClassTraceTime::CLASS_LOAD);
1578
1579 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1580 // Translate to external class name format, i.e., convert '/' chars to '.'
1581 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1582
1583 JavaValue result(T_OBJECT);
1584
1585 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1586
1587 // Call public unsynchronized loadClass(String) directly for all class loaders.
1588 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1589 // acquire a class-name based lock rather than the class loader object lock.
1590 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1591 JavaCalls::call_virtual(&result,
1592 class_loader,
1593 spec_klass,
1594 vmSymbols::loadClass_name(),
1595 vmSymbols::string_class_signature(),
1596 string,
1597 CHECK_NULL);
1598
1599 assert(result.get_type() == T_OBJECT, "just checking");
1600 oop obj = (oop) result.get_jobject();
1601
1602 // Primitive classes return null since forName() can not be
1603 // used to obtain any of the Class objects representing primitives or void
1604 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1605 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1606 // For user defined Java class loaders, check that the name returned is
1607 // the same as that requested. This check is done for the bootstrap
1608 // loader when parsing the class file.
1609 if (class_name == k->name()) {
1610 return k;
1611 }
1612 }
1613 // Class is not found or has the wrong name, return NULL
1614 return NULL;
1615 }
1616 }
1617
1618 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1619 EventClassDefine event;
1620 if (event.should_commit()) {
1621 event.set_definedClass(k);
1622 event.set_definingClassLoader(def_cld);
1623 event.commit();
1624 }
1625 }
1626
1627 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1628
1629 HandleMark hm(THREAD);
1630 ClassLoaderData* loader_data = k->class_loader_data();
1631 Handle class_loader_h(THREAD, loader_data->class_loader());
1632
1633 // for bootstrap and other parallel classloaders don't acquire lock,
1634 // use placeholder token
1635 // If a parallelCapable class loader calls define_instance_class instead of
1636 // find_or_define_instance_class to get here, we have a timing
1637 // hole with systemDictionary updates and check_constraints
1638 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1639 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1640 compute_loader_lock_object(class_loader_h, THREAD)),
1641 "define called without lock");
1642 }
1643
1644 // Check class-loading constraints. Throw exception if violation is detected.
1645 // Grabs and releases SystemDictionary_lock
1646 // The check_constraints/find_class call and update_dictionary sequence
1647 // must be "atomic" for a specific class/classloader pair so we never
1648 // define two different instanceKlasses for that class/classloader pair.
1649 // Existing classloaders will call define_instance_class with the
1650 // classloader lock held
1651 // Parallel classloaders will call find_or_define_instance_class
1652 // which will require a token to perform the define class
1653 Symbol* name_h = k->name();
1654 Dictionary* dictionary = loader_data->dictionary();
1655 unsigned int d_hash = dictionary->compute_hash(name_h);
1656 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1657
1658 // Register class just loaded with class loader (placed in ArrayList)
1659 // Note we do this before updating the dictionary, as this can
1660 // fail with an OutOfMemoryError (if it does, we will *not* put this
1661 // class in the dictionary and will not update the class hierarchy).
1662 // JVMTI FollowReferences needs to find the classes this way.
1663 if (k->class_loader() != NULL) {
1664 methodHandle m(THREAD, Universe::loader_addClass_method());
1665 JavaValue result(T_VOID);
1666 JavaCallArguments args(class_loader_h);
1667 args.push_oop(Handle(THREAD, k->java_mirror()));
1668 JavaCalls::call(&result, m, &args, CHECK);
1669 }
1670
1671 // Add the new class. We need recompile lock during update of CHA.
1672 {
1673 unsigned int p_hash = placeholders()->compute_hash(name_h);
1674 int p_index = placeholders()->hash_to_index(p_hash);
1675
1676 MutexLocker mu_r(THREAD, Compile_lock);
1677
1678 // Add to class hierarchy, initialize vtables, and do possible
1679 // deoptimizations.
1680 add_to_hierarchy(k, CHECK); // No exception, but can block
1681
1682 // Add to systemDictionary - so other classes can see it.
1683 // Grabs and releases SystemDictionary_lock
1684 update_dictionary(d_hash, p_index, p_hash,
1685 k, class_loader_h, THREAD);
1686 }
1687 k->eager_initialize(THREAD);
1688
1689 // notify jvmti
1690 if (JvmtiExport::should_post_class_load()) {
1691 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1692 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1693
1694 }
1695 post_class_define_event(k, loader_data);
1696 }
1697
1698 // Support parallel classloading
1699 // All parallel class loaders, including bootstrap classloader
1700 // lock a placeholder entry for this class/class_loader pair
1701 // to allow parallel defines of different classes for this class loader
1702 // With AllowParallelDefine flag==true, in case they do not synchronize around
1703 // FindLoadedClass/DefineClass, calls, we check for parallel
1704 // loading for them, wait if a defineClass is in progress
1705 // and return the initial requestor's results
1706 // This flag does not apply to the bootstrap classloader.
1707 // With AllowParallelDefine flag==false, call through to define_instance_class
1708 // which will throw LinkageError: duplicate class definition.
1709 // False is the requested default.
1710 // For better performance, the class loaders should synchronize
1711 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1712 // potentially waste time reading and parsing the bytestream.
1713 // Note: VM callers should ensure consistency of k/class_name,class_loader
1714 // Be careful when modifying this code: once you have run
1715 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1716 // you need to find_and_remove it before returning.
1717 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1718 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1719 InstanceKlass* k, TRAPS) {
1720
1721 Symbol* name_h = k->name(); // passed in class_name may be null
1722 ClassLoaderData* loader_data = class_loader_data(class_loader);
1723 Dictionary* dictionary = loader_data->dictionary();
1724
1725 unsigned int d_hash = dictionary->compute_hash(name_h);
1726
1727 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1728 unsigned int p_hash = placeholders()->compute_hash(name_h);
1729 int p_index = placeholders()->hash_to_index(p_hash);
1730 PlaceholderEntry* probe;
1731
1732 {
1733 MutexLocker mu(THREAD, SystemDictionary_lock);
1734 // First check if class already defined
1735 if (is_parallelDefine(class_loader)) {
1736 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1737 if (check != NULL) {
1738 return check;
1739 }
1740 }
1741
1742 // Acquire define token for this class/classloader
1743 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1744 // Wait if another thread defining in parallel
1745 // All threads wait - even those that will throw duplicate class: otherwise
1746 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1747 // if other thread has not finished updating dictionary
1748 while (probe->definer() != NULL) {
1749 SystemDictionary_lock->wait();
1750 }
1751 // Only special cases allow parallel defines and can use other thread's results
1752 // Other cases fall through, and may run into duplicate defines
1753 // caught by finding an entry in the SystemDictionary
1754 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1755 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1756 SystemDictionary_lock->notify_all();
1757 #ifdef ASSERT
1758 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1759 assert(check != NULL, "definer missed recording success");
1760 #endif
1761 return probe->instance_klass();
1762 } else {
1763 // This thread will define the class (even if earlier thread tried and had an error)
1764 probe->set_definer(THREAD);
1765 }
1766 }
1767
1768 define_instance_class(k, THREAD);
1769
1770 Handle linkage_exception = Handle(); // null handle
1771
1772 // definer must notify any waiting threads
1773 {
1774 MutexLocker mu(THREAD, SystemDictionary_lock);
1775 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1776 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1777 if (probe != NULL) {
1778 if (HAS_PENDING_EXCEPTION) {
1779 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1780 CLEAR_PENDING_EXCEPTION;
1781 } else {
1782 probe->set_instance_klass(k);
1783 }
1784 probe->set_definer(NULL);
1785 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1786 SystemDictionary_lock->notify_all();
1787 }
1788 }
1789
1790 // Can't throw exception while holding lock due to rank ordering
1791 if (linkage_exception() != NULL) {
1792 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1793 }
1794
1795 return k;
1796 }
1797
1798 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1799 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1800 if (class_loader.is_null()) {
1801 return Handle(THREAD, _system_loader_lock_obj);
1802 } else {
1803 return class_loader;
1804 }
1805 }
1806
1807 // This method is added to check how often we have to wait to grab loader
1808 // lock. The results are being recorded in the performance counters defined in
1809 // ClassLoader::_sync_systemLoaderLockContentionRate and
1810 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1811 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1812 if (!UsePerfData) {
1813 return;
1814 }
1815
1816 assert(!loader_lock.is_null(), "NULL lock object");
1817
1818 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1819 == ObjectSynchronizer::owner_other) {
1820 // contention will likely happen, so increment the corresponding
1821 // contention counter.
1822 if (loader_lock() == _system_loader_lock_obj) {
1823 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1824 } else {
1825 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1826 }
1827 }
1828 }
1829
1830 // ----------------------------------------------------------------------------
1831 // Lookup
1832
1833 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1834 Symbol* class_name,
1835 Dictionary* dictionary) {
1836 assert_locked_or_safepoint(SystemDictionary_lock);
1837 int index = dictionary->hash_to_index(hash);
1838 return dictionary->find_class(index, hash, class_name);
1839 }
1840
1841
1842 // Basic find on classes in the midst of being loaded
1843 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1844 ClassLoaderData* loader_data) {
1845 assert_locked_or_safepoint(SystemDictionary_lock);
1846 unsigned int p_hash = placeholders()->compute_hash(class_name);
1847 int p_index = placeholders()->hash_to_index(p_hash);
1848 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1849 }
1850
1851
1852 // Used for assertions and verification only
1853 // Precalculating the hash and index is an optimization because there are many lookups
1854 // before adding the class.
1855 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1856 assert_locked_or_safepoint(SystemDictionary_lock);
1857 #ifndef ASSERT
1858 guarantee(VerifyBeforeGC ||
1859 VerifyDuringGC ||
1860 VerifyBeforeExit ||
1861 VerifyDuringStartup ||
1862 VerifyAfterGC, "too expensive");
1863 #endif
1864
1865 Dictionary* dictionary = loader_data->dictionary();
1866 unsigned int d_hash = dictionary->compute_hash(class_name);
1867 return find_class(d_hash, class_name, dictionary);
1868 }
1869
1870
1871 // ----------------------------------------------------------------------------
1872 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1873 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1874 // before a new class is used.
1875
1876 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1877 assert(k != NULL, "just checking");
1878 if (Universe::is_fully_initialized()) {
1879 assert_locked_or_safepoint(Compile_lock);
1880 }
1881
1882 k->set_init_state(InstanceKlass::loaded);
1883 // make sure init_state store is already done.
1884 // The compiler reads the hierarchy outside of the Compile_lock.
1885 // Access ordering is used to add to hierarchy.
1886
1887 // Link into hierachy.
1888 k->append_to_sibling_list(); // add to superklass/sibling list
1889 k->process_interfaces(THREAD); // handle all "implements" declarations
1890
1891 // Now flush all code that depended on old class hierarchy.
1892 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1893 if (Universe::is_fully_initialized()) {
1894 CodeCache::flush_dependents_on(k);
1895 }
1896 }
1897
1898 // ----------------------------------------------------------------------------
1899 // GC support
1900
1901 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1902 // Note: anonymous classes are not in the SD.
1903 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1904
1905 bool unloading_occurred;
1906 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1907 {
1908 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1909 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1910 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1911 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1912 if (unloading_occurred) {
1913 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1914 JFR_ONLY(Jfr::on_unloading_classes();)
1915
1916 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1917 ClassLoaderDataGraph::clean_module_and_package_info();
1918 constraints()->purge_loader_constraints();
1919 resolution_errors()->purge_resolution_errors();
1920 }
1921 }
1922
1923 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1924
1925 if (unloading_occurred) {
1926 SymbolTable::trigger_cleanup();
1927
1928 // Oops referenced by the protection domain cache table may get unreachable independently
1929 // of the class loader (eg. cached protection domain oops). So we need to
1930 // explicitly unlink them here.
1931 // All protection domain oops are linked to the caller class, so if nothing
1932 // unloads, this is not needed.
1933 _pd_cache_table->trigger_cleanup();
1934 }
1935
1936 return unloading_occurred;
1937 }
1938
1939 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
1940 f->do_oop(&_java_system_loader);
1941 f->do_oop(&_java_platform_loader);
1942 f->do_oop(&_system_loader_lock_obj);
1943 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1944
1945 // Visit extra methods
1946 invoke_method_table()->oops_do(f);
1947
1948 if (include_handles) {
1949 OopStorageSet::vm_global()->oops_do(f);
1950 }
1951 }
1952
1953 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1954 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1955 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1956 it->push(well_known_klass_addr((WKID)id));
1957 }
1958 }
1959
1960 void SystemDictionary::methods_do(void f(Method*)) {
1961 // Walk methods in loaded classes
1962 MutexLocker ml(ClassLoaderDataGraph_lock);
1963 ClassLoaderDataGraph::methods_do(f);
1964 // Walk method handle intrinsics
1965 invoke_method_table()->methods_do(f);
1966 }
1967
1968 // ----------------------------------------------------------------------------
1969 // Initialization
1970
1971 void SystemDictionary::initialize(TRAPS) {
1972 // Allocate arrays
1973 _placeholders = new PlaceholderTable(_placeholder_table_size);
1974 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1975 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1976 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1977 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1978
1979 // Allocate private object used as system class loader lock
1980 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1981 // Initialize basic classes
1982 resolve_well_known_classes(CHECK);
1983 }
1984
1985 // Compact table of directions on the initialization of klasses:
1986 static const short wk_init_info[] = {
1987 #define WK_KLASS_INIT_INFO(name, symbol) \
1988 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1989
1990 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1991 #undef WK_KLASS_INIT_INFO
1992 0
1993 };
1994
1995 #ifdef ASSERT
1996 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1997 int sid;
1998 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1999 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2000 if (class_name == symbol) {
2001 return true;
2002 }
2003 }
2004 return false;
2005 }
2006 #endif
2007
2008 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2009 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2010 int sid = wk_init_info[id - FIRST_WKID];
2011 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2012 InstanceKlass** klassp = &_well_known_klasses[id];
2013
2014 #if INCLUDE_CDS
2015 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2016 InstanceKlass* k = *klassp;
2017 assert(k->is_shared_boot_class(), "must be");
2018
2019 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2020 quick_resolve(k, loader_data, Handle(), CHECK_false);
2021 return true;
2022 }
2023 #endif // INCLUDE_CDS
2024
2025 if (!is_wk_klass_loaded(*klassp)) {
2026 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2027 (*klassp) = InstanceKlass::cast(k);
2028 }
2029 return ((*klassp) != NULL);
2030 }
2031
2032 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2033 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2034 for (int id = (int)start_id; id < (int)limit_id; id++) {
2035 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2036 resolve_wk_klass((WKID)id, CHECK);
2037 }
2038
2039 // move the starting value forward to the limit:
2040 start_id = limit_id;
2041 }
2042
2043 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2044 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2045
2046 // Create the ModuleEntry for java.base. This call needs to be done here,
2047 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2048 ClassLoader::classLoader_init2(CHECK);
2049
2050 // Preload commonly used klasses
2051 WKID scan = FIRST_WKID;
2052 // first do Object, then String, Class
2053 #if INCLUDE_CDS
2054 if (UseSharedSpaces) {
2055 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2056
2057 // It's unsafe to access the archived heap regions before they
2058 // are fixed up, so we must do the fixup as early as possible
2059 // before the archived java objects are accessed by functions
2060 // such as java_lang_Class::restore_archived_mirror and
2061 // ConstantPool::restore_unshareable_info (restores the archived
2062 // resolved_references array object).
2063 //
2064 // HeapShared::fixup_mapped_heap_regions() fills the empty
2065 // spaces in the archived heap regions and may use
2066 // SystemDictionary::Object_klass(), so we can do this only after
2067 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2068 // call. No mirror objects are accessed/restored in the above call.
2069 // Mirrors are restored after java.lang.Class is loaded.
2070 HeapShared::fixup_mapped_heap_regions();
2071
2072 // Initialize the constant pool for the Object_class
2073 assert(Object_klass()->is_shared(), "must be");
2074 Object_klass()->constants()->restore_unshareable_info(CHECK);
2075 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2076 } else
2077 #endif
2078 {
2079 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2080 }
2081
2082 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2083
2084 java_lang_Object::register_natives(CHECK);
2085
2086 // Calculate offsets for String and Class classes since they are loaded and
2087 // can be used after this point.
2088 java_lang_String::compute_offsets();
2089 java_lang_Class::compute_offsets();
2090
2091 // Fixup mirrors for classes loaded before java.lang.Class.
2092 Universe::initialize_basic_type_mirrors(CHECK);
2093 Universe::fixup_mirrors(CHECK);
2094
2095 // do a bunch more:
2096 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2097
2098 // Preload ref klasses and set reference types
2099 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2100 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2101
2102 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2103 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2104 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2105 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2106 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2107
2108 // JSR 292 classes
2109 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2110 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2111 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2112 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2113 WKID last = WKID_LIMIT;
2114 resolve_wk_klasses_until(last, scan, CHECK);
2115
2116 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2117 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2118 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2119 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2120 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2121 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2122 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2123 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2124 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2125 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2126
2127 #ifdef ASSERT
2128 if (UseSharedSpaces) {
2129 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2130 "All well known classes must be resolved in JVMTI early phase"));
2131 for (int i = FIRST_WKID; i < last; i++) {
2132 InstanceKlass* k = _well_known_klasses[i];
2133 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2134 }
2135 }
2136 #endif
2137 }
2138
2139 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2140 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2141 BasicType SystemDictionary::box_klass_type(Klass* k) {
2142 assert(k != NULL, "");
2143 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2144 if (_box_klasses[i] == k)
2145 return (BasicType)i;
2146 }
2147 return T_OBJECT;
2148 }
2149
2150 // Constraints on class loaders. The details of the algorithm can be
2151 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2152 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2153 // that the dictionary needs to maintain a set of contraints that
2154 // must be satisfied by all classes in the dictionary.
2155 // if defining is true, then LinkageError if already in dictionary
2156 // if initiating loader, then ok if InstanceKlass matches existing entry
2157
2158 void SystemDictionary::check_constraints(unsigned int d_hash,
2159 InstanceKlass* k,
2160 Handle class_loader,
2161 bool defining,
2162 TRAPS) {
2163 ResourceMark rm(THREAD);
2164 stringStream ss;
2165 bool throwException = false;
2166
2167 {
2168 Symbol *name = k->name();
2169 ClassLoaderData *loader_data = class_loader_data(class_loader);
2170
2171 MutexLocker mu(THREAD, SystemDictionary_lock);
2172
2173 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2174 if (check != NULL) {
2175 // If different InstanceKlass - duplicate class definition,
2176 // else - ok, class loaded by a different thread in parallel.
2177 // We should only have found it if it was done loading and ok to use.
2178 // The dictionary only holds instance classes, placeholders
2179 // also hold array classes.
2180
2181 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2182 if ((defining == true) || (k != check)) {
2183 throwException = true;
2184 ss.print("loader %s", loader_data->loader_name_and_id());
2185 ss.print(" attempted duplicate %s definition for %s. (%s)",
2186 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2187 } else {
2188 return;
2189 }
2190 }
2191
2192 #ifdef ASSERT
2193 Symbol* ph_check = find_placeholder(name, loader_data);
2194 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2195 #endif
2196
2197 if (throwException == false) {
2198 if (constraints()->check_or_update(k, class_loader, name) == false) {
2199 throwException = true;
2200 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2201 ss.print(" wants to load %s %s.",
2202 k->external_kind(), k->external_name());
2203 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2204 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2205 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2206 existing_klass->external_kind(),
2207 existing_klass->class_loader_data()->loader_name_and_id(),
2208 existing_klass->class_in_module_of_loader(false, true));
2209 } else {
2210 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2211 }
2212 }
2213 }
2214 }
2215
2216 // Throw error now if needed (cannot throw while holding
2217 // SystemDictionary_lock because of rank ordering)
2218 if (throwException == true) {
2219 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2220 }
2221 }
2222
2223 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2224 // have been called.
2225 void SystemDictionary::update_dictionary(unsigned int d_hash,
2226 int p_index, unsigned int p_hash,
2227 InstanceKlass* k,
2228 Handle class_loader,
2229 TRAPS) {
2230 // Compile_lock prevents systemDictionary updates during compilations
2231 assert_locked_or_safepoint(Compile_lock);
2232 Symbol* name = k->name();
2233 ClassLoaderData *loader_data = class_loader_data(class_loader);
2234
2235 {
2236 MutexLocker mu1(THREAD, SystemDictionary_lock);
2237
2238 // Make a new dictionary entry.
2239 Dictionary* dictionary = loader_data->dictionary();
2240 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2241 if (sd_check == NULL) {
2242 dictionary->add_klass(d_hash, name, k);
2243 }
2244 #ifdef ASSERT
2245 sd_check = find_class(d_hash, name, dictionary);
2246 assert (sd_check != NULL, "should have entry in dictionary");
2247 // Note: there may be a placeholder entry: for circularity testing
2248 // or for parallel defines
2249 #endif
2250 SystemDictionary_lock->notify_all();
2251 }
2252 }
2253
2254
2255 // Try to find a class name using the loader constraints. The
2256 // loader constraints might know about a class that isn't fully loaded
2257 // yet and these will be ignored.
2258 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2259 Symbol* class_name, Handle class_loader, TRAPS) {
2260
2261 // First see if it has been loaded directly.
2262 // Force the protection domain to be null. (This removes protection checks.)
2263 Handle no_protection_domain;
2264 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2265 no_protection_domain, CHECK_NULL);
2266 if (klass != NULL)
2267 return klass;
2268
2269 // Now look to see if it has been loaded elsewhere, and is subject to
2270 // a loader constraint that would require this loader to return the
2271 // klass that is already loaded.
2272 if (Signature::is_array(class_name)) {
2273 // For array classes, their Klass*s are not kept in the
2274 // constraint table. The element Klass*s are.
2275 SignatureStream ss(class_name, false);
2276 int ndims = ss.skip_array_prefix(); // skip all '['s
2277 BasicType t = ss.type();
2278 if (t != T_OBJECT) {
2279 klass = Universe::typeArrayKlassObj(t);
2280 } else {
2281 MutexLocker mu(THREAD, SystemDictionary_lock);
2282 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2283 }
2284 // If element class already loaded, allocate array klass
2285 if (klass != NULL) {
2286 klass = klass->array_klass_or_null(ndims);
2287 }
2288 } else {
2289 MutexLocker mu(THREAD, SystemDictionary_lock);
2290 // Non-array classes are easy: simply check the constraint table.
2291 klass = constraints()->find_constrained_klass(class_name, class_loader);
2292 }
2293
2294 return klass;
2295 }
2296
2297 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2298 Klass* klass_being_linked,
2299 Handle class_loader1,
2300 Handle class_loader2,
2301 Thread* THREAD) {
2302 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2303 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2304
2305 Symbol* constraint_name = NULL;
2306
2307 if (!Signature::is_array(class_name)) {
2308 constraint_name = class_name;
2309 } else {
2310 // For array classes, their Klass*s are not kept in the
2311 // constraint table. The element classes are.
2312 SignatureStream ss(class_name, false);
2313 ss.skip_array_prefix(); // skip all '['s
2314 if (!ss.has_envelope()) {
2315 return true; // primitive types always pass
2316 }
2317 constraint_name = ss.as_symbol();
2318 // Increment refcount to keep constraint_name alive after
2319 // SignatureStream is destructed. It will be decremented below
2320 // before returning.
2321 constraint_name->increment_refcount();
2322 }
2323
2324 Dictionary* dictionary1 = loader_data1->dictionary();
2325 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2326
2327 Dictionary* dictionary2 = loader_data2->dictionary();
2328 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2329
2330 {
2331 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2332 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2333 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2334 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2335 klass2, class_loader2);
2336 #if INCLUDE_CDS
2337 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2338 !klass_being_linked->is_shared()) {
2339 SystemDictionaryShared::record_linking_constraint(constraint_name,
2340 InstanceKlass::cast(klass_being_linked),
2341 class_loader1, class_loader2, THREAD);
2342 }
2343 #endif // INCLUDE_CDS
2344 if (Signature::is_array(class_name)) {
2345 constraint_name->decrement_refcount();
2346 }
2347 return result;
2348 }
2349 }
2350
2351 // Add entry to resolution error table to record the error when the first
2352 // attempt to resolve a reference to a class has failed.
2353 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2354 Symbol* error, Symbol* message) {
2355 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2356 int index = resolution_errors()->hash_to_index(hash);
2357 {
2358 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2359 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2360 }
2361 }
2362
2363 // Delete a resolution error for RedefineClasses for a constant pool is going away
2364 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2365 resolution_errors()->delete_entry(pool);
2366 }
2367
2368 // Lookup resolution error table. Returns error if found, otherwise NULL.
2369 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2370 Symbol** message) {
2371 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2372 int index = resolution_errors()->hash_to_index(hash);
2373 {
2374 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2375 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2376 if (entry != NULL) {
2377 *message = entry->message();
2378 return entry->error();
2379 } else {
2380 return NULL;
2381 }
2382 }
2383 }
2384
2385 // Add an entry to resolution error table to record an error in resolving or
2386 // validating a nest host. This is used to construct informative error
2387 // messages when IllegalAccessError's occur. If an entry already exists it will
2388 // be updated with the nest host error message.
2389 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2390 int which,
2391 const char* message) {
2392 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2393 int index = resolution_errors()->hash_to_index(hash);
2394 {
2395 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2396 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2397 if (entry != NULL) {
2398 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2399 entry->set_nest_host_error(message);
2400 } else {
2401 resolution_errors()->add_entry(index, hash, pool, which, message);
2402 }
2403 }
2404 }
2405
2406 // Lookup any nest host error
2407 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2408 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2409 int index = resolution_errors()->hash_to_index(hash);
2410 {
2411 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2412 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2413 if (entry != NULL) {
2414 return entry->nest_host_error();
2415 } else {
2416 return NULL;
2417 }
2418 }
2419 }
2420
2421
2422 // Signature constraints ensure that callers and callees agree about
2423 // the meaning of type names in their signatures. This routine is the
2424 // intake for constraints. It collects them from several places:
2425 //
2426 // * LinkResolver::resolve_method (if check_access is true) requires
2427 // that the resolving class (the caller) and the defining class of
2428 // the resolved method (the callee) agree on each type in the
2429 // method's signature.
2430 //
2431 // * LinkResolver::resolve_interface_method performs exactly the same
2432 // checks.
2433 //
2434 // * LinkResolver::resolve_field requires that the constant pool
2435 // attempting to link to a field agree with the field's defining
2436 // class about the type of the field signature.
2437 //
2438 // * klassVtable::initialize_vtable requires that, when a class
2439 // overrides a vtable entry allocated by a superclass, that the
2440 // overriding method (i.e., the callee) agree with the superclass
2441 // on each type in the method's signature.
2442 //
2443 // * klassItable::initialize_itable requires that, when a class fills
2444 // in its itables, for each non-abstract method installed in an
2445 // itable, the method (i.e., the callee) agree with the interface
2446 // on each type in the method's signature.
2447 //
2448 // All those methods have a boolean (check_access, checkconstraints)
2449 // which turns off the checks. This is used from specialized contexts
2450 // such as bootstrapping, dumping, and debugging.
2451 //
2452 // No direct constraint is placed between the class and its
2453 // supertypes. Constraints are only placed along linked relations
2454 // between callers and callees. When a method overrides or implements
2455 // an abstract method in a supertype (superclass or interface), the
2456 // constraints are placed as if the supertype were the caller to the
2457 // overriding method. (This works well, since callers to the
2458 // supertype have already established agreement between themselves and
2459 // the supertype.) As a result of all this, a class can disagree with
2460 // its supertype about the meaning of a type name, as long as that
2461 // class neither calls a relevant method of the supertype, nor is
2462 // called (perhaps via an override) from the supertype.
2463 //
2464 //
2465 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2466 //
2467 // Make sure all class components (including arrays) in the given
2468 // signature will be resolved to the same class in both loaders.
2469 // Returns the name of the type that failed a loader constraint check, or
2470 // NULL if no constraint failed. No exception except OOME is thrown.
2471 // Arrays are not added to the loader constraint table, their elements are.
2472 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2473 Klass* klass_being_linked,
2474 Handle loader1, Handle loader2,
2475 bool is_method, TRAPS) {
2476 // Nothing to do if loaders are the same.
2477 if (loader1() == loader2()) {
2478 return NULL;
2479 }
2480
2481 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2482 if (ss.is_reference()) {
2483 Symbol* sig = ss.as_symbol();
2484 // Note: In the future, if template-like types can take
2485 // arguments, we will want to recognize them and dig out class
2486 // names hiding inside the argument lists.
2487 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2488 return sig;
2489 }
2490 }
2491 }
2492 return NULL;
2493 }
2494
2495 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2496 Symbol* signature,
2497 TRAPS) {
2498 methodHandle empty;
2499 assert(MethodHandles::is_signature_polymorphic(iid) &&
2500 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2501 iid != vmIntrinsics::_invokeGeneric,
2502 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2503
2504 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2505 int index = invoke_method_table()->hash_to_index(hash);
2506 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2507 methodHandle m;
2508 if (spe == NULL || spe->method() == NULL) {
2509 spe = NULL;
2510 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2511 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2512 if (!Arguments::is_interpreter_only()) {
2513 // Generate a compiled form of the MH intrinsic.
2514 AdapterHandlerLibrary::create_native_wrapper(m);
2515 // Check if have the compiled code.
2516 if (!m->has_compiled_code()) {
2517 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2518 "Out of space in CodeCache for method handle intrinsic");
2519 }
2520 }
2521 // Now grab the lock. We might have to throw away the new method,
2522 // if a racing thread has managed to install one at the same time.
2523 {
2524 MutexLocker ml(THREAD, SystemDictionary_lock);
2525 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2526 if (spe == NULL)
2527 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2528 if (spe->method() == NULL)
2529 spe->set_method(m());
2530 }
2531 }
2532
2533 assert(spe != NULL && spe->method() != NULL, "");
2534 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2535 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2536 "MH intrinsic invariant");
2537 return spe->method();
2538 }
2539
2540 // Helper for unpacking the return value from linkMethod and linkCallSite.
2541 static Method* unpack_method_and_appendix(Handle mname,
2542 Klass* accessing_klass,
2543 objArrayHandle appendix_box,
2544 Handle* appendix_result,
2545 TRAPS) {
2546 if (mname.not_null()) {
2547 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2548 if (m != NULL) {
2549 oop appendix = appendix_box->obj_at(0);
2550 LogTarget(Info, methodhandles) lt;
2551 if (lt.develop_is_enabled()) {
2552 ResourceMark rm(THREAD);
2553 LogStream ls(lt);
2554 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2555 m->print_on(&ls);
2556 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2557 ls.cr();
2558 }
2559
2560 (*appendix_result) = Handle(THREAD, appendix);
2561 // the target is stored in the cpCache and if a reference to this
2562 // MemberName is dropped we need a way to make sure the
2563 // class_loader containing this method is kept alive.
2564 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2565 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2566 this_key->record_dependency(m->method_holder());
2567 return mh();
2568 }
2569 }
2570 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2571 }
2572
2573 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2574 Symbol* name,
2575 Symbol* signature,
2576 Klass* accessing_klass,
2577 Handle *appendix_result,
2578 TRAPS) {
2579 assert(THREAD->can_call_java() ,"");
2580 Handle method_type =
2581 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2582
2583 int ref_kind = JVM_REF_invokeVirtual;
2584 oop name_oop = StringTable::intern(name, CHECK_NULL);
2585 Handle name_str (THREAD, name_oop);
2586 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2587 assert(appendix_box->obj_at(0) == NULL, "");
2588
2589 // This should not happen. JDK code should take care of that.
2590 if (accessing_klass == NULL || method_type.is_null()) {
2591 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2592 }
2593
2594 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2595 JavaCallArguments args;
2596 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2597 args.push_int(ref_kind);
2598 args.push_oop(Handle(THREAD, klass->java_mirror()));
2599 args.push_oop(name_str);
2600 args.push_oop(method_type);
2601 args.push_oop(appendix_box);
2602 JavaValue result(T_OBJECT);
2603 JavaCalls::call_static(&result,
2604 SystemDictionary::MethodHandleNatives_klass(),
2605 vmSymbols::linkMethod_name(),
2606 vmSymbols::linkMethod_signature(),
2607 &args, CHECK_NULL);
2608 Handle mname(THREAD, (oop) result.get_jobject());
2609 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2610 }
2611
2612 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2613 // We must ensure that all class loaders everywhere will reach this class, for any client.
2614 // This is a safe bet for public classes in java.lang, such as Object and String.
2615 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2616 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2617 static bool is_always_visible_class(oop mirror) {
2618 Klass* klass = java_lang_Class::as_Klass(mirror);
2619 if (klass->is_objArray_klass()) {
2620 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2621 }
2622 if (klass->is_typeArray_klass()) {
2623 return true; // primitive array
2624 }
2625 assert(klass->is_instance_klass(), "%s", klass->external_name());
2626 return klass->is_public() &&
2627 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2628 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2629 }
2630
2631 // Find or construct the Java mirror (java.lang.Class instance) for
2632 // the given field type signature, as interpreted relative to the
2633 // given class loader. Handles primitives, void, references, arrays,
2634 // and all other reflectable types, except method types.
2635 // N.B. Code in reflection should use this entry point.
2636 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2637 Klass* accessing_klass,
2638 Handle class_loader,
2639 Handle protection_domain,
2640 SignatureStream::FailureMode failure_mode,
2641 TRAPS) {
2642 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2643 "one or the other, or perhaps neither");
2644
2645 // What we have here must be a valid field descriptor,
2646 // and all valid field descriptors are supported.
2647 // Produce the same java.lang.Class that reflection reports.
2648 if (accessing_klass != NULL) {
2649 class_loader = Handle(THREAD, accessing_klass->class_loader());
2650 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2651 }
2652 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2653 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2654 if (mirror_oop == NULL) {
2655 return Handle(); // report failure this way
2656 }
2657 Handle mirror(THREAD, mirror_oop);
2658
2659 if (accessing_klass != NULL) {
2660 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2661 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2662 if (sel_klass != NULL) {
2663 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2664 }
2665 }
2666 return mirror;
2667 }
2668
2669
2670 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2671 // signature, as interpreted relative to the given class loader.
2672 // Because of class loader constraints, all method handle usage must be
2673 // consistent with this loader.
2674 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2675 Klass* accessing_klass,
2676 TRAPS) {
2677 Handle empty;
2678 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2679 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2680 int index = invoke_method_table()->hash_to_index(hash);
2681 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2682 if (spe != NULL && spe->method_type() != NULL) {
2683 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2684 return Handle(THREAD, spe->method_type());
2685 } else if (!THREAD->can_call_java()) {
2686 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2687 return Handle(); // do not attempt from within compiler, unless it was cached
2688 }
2689
2690 Handle class_loader, protection_domain;
2691 if (accessing_klass != NULL) {
2692 class_loader = Handle(THREAD, accessing_klass->class_loader());
2693 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2694 }
2695 bool can_be_cached = true;
2696 int npts = ArgumentCount(signature).size();
2697 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2698 int arg = 0;
2699 Handle rt; // the return type from the signature
2700 ResourceMark rm(THREAD);
2701 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2702 oop mirror = NULL;
2703 if (can_be_cached) {
2704 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2705 mirror = ss.as_java_mirror(Handle(), Handle(),
2706 SignatureStream::ReturnNull, CHECK_(empty));
2707 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2708 // Fall back to accessing_klass context.
2709 can_be_cached = false;
2710 }
2711 }
2712 if (!can_be_cached) {
2713 // Resolve, throwing a real error if it doesn't work.
2714 mirror = ss.as_java_mirror(class_loader, protection_domain,
2715 SignatureStream::NCDFError, CHECK_(empty));
2716 }
2717 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2718 if (ss.at_return_type())
2719 rt = Handle(THREAD, mirror);
2720 else
2721 pts->obj_at_put(arg++, mirror);
2722
2723 // Check accessibility.
2724 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2725 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2726 mirror = NULL; // safety
2727 // Emulate ConstantPool::verify_constant_pool_resolve.
2728 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2729 }
2730 }
2731 assert(arg == npts, "");
2732
2733 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2734 JavaCallArguments args(Handle(THREAD, rt()));
2735 args.push_oop(pts);
2736 JavaValue result(T_OBJECT);
2737 JavaCalls::call_static(&result,
2738 SystemDictionary::MethodHandleNatives_klass(),
2739 vmSymbols::findMethodHandleType_name(),
2740 vmSymbols::findMethodHandleType_signature(),
2741 &args, CHECK_(empty));
2742 Handle method_type(THREAD, (oop) result.get_jobject());
2743
2744 if (can_be_cached) {
2745 // We can cache this MethodType inside the JVM.
2746 MutexLocker ml(THREAD, SystemDictionary_lock);
2747 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2748 if (spe == NULL)
2749 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2750 if (spe->method_type() == NULL) {
2751 spe->set_method_type(method_type());
2752 }
2753 }
2754
2755 // report back to the caller with the MethodType
2756 return method_type;
2757 }
2758
2759 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2760 Klass* accessing_klass,
2761 TRAPS) {
2762 Handle empty;
2763 ResourceMark rm(THREAD);
2764 SignatureStream ss(signature, /*is_method=*/ false);
2765 if (!ss.is_done()) {
2766 Handle class_loader, protection_domain;
2767 if (accessing_klass != NULL) {
2768 class_loader = Handle(THREAD, accessing_klass->class_loader());
2769 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2770 }
2771 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2772 ss.next();
2773 if (ss.is_done()) {
2774 return Handle(THREAD, mirror);
2775 }
2776 }
2777 return empty;
2778 }
2779
2780 // Ask Java code to find or construct a method handle constant.
2781 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2782 int ref_kind, //e.g., JVM_REF_invokeVirtual
2783 Klass* callee,
2784 Symbol* name,
2785 Symbol* signature,
2786 TRAPS) {
2787 Handle empty;
2788 if (caller == NULL) {
2789 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2790 }
2791 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2792 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2793
2794 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2795 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2796 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2797 java_lang_invoke_MemberName::set_name (mname(), name_str());
2798 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2799 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2800
2801 if (ref_kind == JVM_REF_invokeVirtual &&
2802 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2803 // Skip resolution for public signature polymorphic methods such as
2804 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2805 // They require appendix argument which MemberName resolution doesn't handle.
2806 // There's special logic on JDK side to handle them
2807 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2808 } else {
2809 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2810 }
2811
2812 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2813 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2814
2815 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2816 JavaCallArguments args;
2817 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2818 args.push_int(ref_kind);
2819 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2820 args.push_oop(name_str);
2821 args.push_oop(type);
2822 JavaValue result(T_OBJECT);
2823 JavaCalls::call_static(&result,
2824 SystemDictionary::MethodHandleNatives_klass(),
2825 vmSymbols::linkMethodHandleConstant_name(),
2826 vmSymbols::linkMethodHandleConstant_signature(),
2827 &args, CHECK_(empty));
2828 return Handle(THREAD, (oop) result.get_jobject());
2829 }
2830
2831 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2832 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2833 // with linkage results being stored back into the bootstrap specifier.
2834 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2835 // Resolve the bootstrap specifier, its name, type, and static arguments
2836 bootstrap_specifier.resolve_bsm(CHECK);
2837
2838 // This should not happen. JDK code should take care of that.
2839 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2840 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2841 }
2842
2843 bool is_indy = bootstrap_specifier.is_method_call();
2844 objArrayHandle appendix_box;
2845 if (is_indy) {
2846 // Some method calls may require an appendix argument. Arrange to receive it.
2847 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2848 assert(appendix_box->obj_at(0) == NULL, "");
2849 }
2850
2851 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2852 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2853 JavaCallArguments args;
2854 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2855 args.push_int(bootstrap_specifier.bss_index());
2856 args.push_oop(bootstrap_specifier.bsm());
2857 args.push_oop(bootstrap_specifier.name_arg());
2858 args.push_oop(bootstrap_specifier.type_arg());
2859 args.push_oop(bootstrap_specifier.arg_values());
2860 if (is_indy) {
2861 args.push_oop(appendix_box);
2862 }
2863 JavaValue result(T_OBJECT);
2864 JavaCalls::call_static(&result,
2865 SystemDictionary::MethodHandleNatives_klass(),
2866 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2867 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2868 &args, CHECK);
2869
2870 Handle value(THREAD, (oop) result.get_jobject());
2871 if (is_indy) {
2872 Handle appendix;
2873 Method* method = unpack_method_and_appendix(value,
2874 bootstrap_specifier.caller(),
2875 appendix_box,
2876 &appendix, CHECK);
2877 methodHandle mh(THREAD, method);
2878 bootstrap_specifier.set_resolved_method(mh, appendix);
2879 } else {
2880 bootstrap_specifier.set_resolved_value(value);
2881 }
2882
2883 // sanity check
2884 assert(bootstrap_specifier.is_resolved() ||
2885 (bootstrap_specifier.is_method_call() &&
2886 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2887 }
2888
2889 // Protection domain cache table handling
2890
2891 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2892 return _pd_cache_table->get(protection_domain);
2893 }
2894
2895 // ----------------------------------------------------------------------------
2896
2897 void SystemDictionary::print_on(outputStream *st) {
2898 CDS_ONLY(SystemDictionaryShared::print_on(st));
2899 GCMutexLocker mu(SystemDictionary_lock);
2900
2901 ClassLoaderDataGraph::print_dictionary(st);
2902
2903 // Placeholders
2904 placeholders()->print_on(st);
2905 st->cr();
2906
2907 // loader constraints - print under SD_lock
2908 constraints()->print_on(st);
2909 st->cr();
2910
2911 _pd_cache_table->print_on(st);
2912 st->cr();
2913 }
2914
2915 void SystemDictionary::print() { print_on(tty); }
2916
2917 void SystemDictionary::verify() {
2918 guarantee(constraints() != NULL,
2919 "Verify of loader constraints failed");
2920 guarantee(placeholders()->number_of_entries() >= 0,
2921 "Verify of placeholders failed");
2922
2923 GCMutexLocker mu(SystemDictionary_lock);
2924
2925 // Verify dictionary
2926 ClassLoaderDataGraph::verify_dictionary();
2927
2928 placeholders()->verify();
2929
2930 // Verify constraint table
2931 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2932 constraints()->verify(placeholders());
2933
2934 _pd_cache_table->verify();
2935 }
2936
2937 void SystemDictionary::dump(outputStream *st, bool verbose) {
2938 assert_locked_or_safepoint(SystemDictionary_lock);
2939 if (verbose) {
2940 print_on(st);
2941 } else {
2942 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2943 ClassLoaderDataGraph::print_table_statistics(st);
2944 placeholders()->print_table_statistics(st, "Placeholder Table");
2945 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2946 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2947 }
2948 }
2949
2950 TableStatistics SystemDictionary::placeholders_statistics() {
2951 MutexLocker ml(SystemDictionary_lock);
2952 return placeholders()->statistics_calculate();
2953 }
2954
2955 TableStatistics SystemDictionary::loader_constraints_statistics() {
2956 MutexLocker ml(SystemDictionary_lock);
2957 return constraints()->statistics_calculate();
2958 }
2959
2960 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2961 MutexLocker ml(SystemDictionary_lock);
2962 return pd_cache_table()->statistics_calculate();
2963 }
2964
2965 // Utility for dumping dictionaries.
2966 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2967 DCmdWithParser(output, heap),
2968 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2969 "BOOLEAN", false, "false") {
2970 _dcmdparser.add_dcmd_option(&_verbose);
2971 }
2972
2973 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2974 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2975 _verbose.value());
2976 VMThread::execute(&dumper);
2977 }
2978
2979 int SystemDictionaryDCmd::num_arguments() {
2980 ResourceMark rm;
2981 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2982 if (dcmd != NULL) {
2983 DCmdMark mark(dcmd);
2984 return dcmd->_dcmdparser.num_arguments();
2985 } else {
2986 return 0;
2987 }
2988 }