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