1 /*
2 * Copyright (c) 1997, 2019, 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 "interpreter/bytecodeStream.hpp"
51 #include "interpreter/interpreter.hpp"
52 #include "jfr/jfrEvents.hpp"
53 #include "logging/log.hpp"
54 #include "logging/logStream.hpp"
55 #include "memory/filemap.hpp"
56 #include "memory/heapShared.hpp"
57 #include "memory/metaspaceClosure.hpp"
58 #include "memory/oopFactory.hpp"
59 #include "memory/resourceArea.hpp"
60 #include "memory/universe.hpp"
61 #include "oops/access.inline.hpp"
62 #include "oops/instanceKlass.hpp"
63 #include "oops/instanceRefKlass.hpp"
64 #include "oops/klass.inline.hpp"
65 #include "oops/method.inline.hpp"
66 #include "oops/methodData.hpp"
67 #include "oops/objArrayKlass.hpp"
68 #include "oops/objArrayOop.inline.hpp"
69 #include "oops/oop.inline.hpp"
70 #include "oops/symbol.hpp"
71 #include "oops/typeArrayKlass.hpp"
72 #include "oops/valueKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/fieldType.hpp"
78 #include "runtime/handles.inline.hpp"
79 #include "runtime/java.hpp"
80 #include "runtime/javaCalls.hpp"
81 #include "runtime/mutexLocker.hpp"
82 #include "runtime/orderAccess.hpp"
83 #include "runtime/os.hpp"
84 #include "runtime/sharedRuntime.hpp"
85 #include "runtime/signature.hpp"
86 #include "services/classLoadingService.hpp"
87 #include "services/diagnosticCommand.hpp"
88 #include "services/threadService.hpp"
89 #include "utilities/macros.hpp"
90 #if INCLUDE_CDS
91 #include "classfile/systemDictionaryShared.hpp"
92 #endif
93 #if INCLUDE_JFR
94 #include "jfr/jfr.hpp"
95 #endif
96
97 PlaceholderTable* SystemDictionary::_placeholders = NULL;
98 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
99 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
100 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
101 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
102
103 int SystemDictionary::_number_of_modifications = 0;
104 oop SystemDictionary::_system_loader_lock_obj = NULL;
105
106 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
107 = { NULL /*, NULL...*/ };
108
109 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
110
111 oop SystemDictionary::_java_system_loader = NULL;
112 oop SystemDictionary::_java_platform_loader = NULL;
113
114 bool SystemDictionary::_has_checkPackageAccess = false;
115
116 // Default ProtectionDomainCacheSize value
117
118 const int defaultProtectionDomainCacheSize = 1009;
119
120 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
121
122
123 // ----------------------------------------------------------------------------
124 // Java-level SystemLoader and PlatformLoader
125
126 oop SystemDictionary::java_system_loader() {
127 return _java_system_loader;
128 }
129
130 oop SystemDictionary::java_platform_loader() {
131 return _java_platform_loader;
132 }
133
134 void SystemDictionary::compute_java_loaders(TRAPS) {
135 JavaValue result(T_OBJECT);
136 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
137 JavaCalls::call_static(&result,
138 class_loader_klass,
139 vmSymbols::getSystemClassLoader_name(),
140 vmSymbols::void_classloader_signature(),
141 CHECK);
142
143 _java_system_loader = (oop)result.get_jobject();
144
145 JavaCalls::call_static(&result,
146 class_loader_klass,
147 vmSymbols::getPlatformClassLoader_name(),
148 vmSymbols::void_classloader_signature(),
149 CHECK);
150
151 _java_platform_loader = (oop)result.get_jobject();
152 }
153
154 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
155 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
156 return ClassLoaderDataGraph::find_or_create(class_loader);
157 }
158
159 // ----------------------------------------------------------------------------
160 // Parallel class loading check
161
162 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
163 if (class_loader.is_null()) return true;
164 if (AlwaysLockClassLoader) return false;
165 return java_lang_ClassLoader::parallelCapable(class_loader());
166 }
167 // ----------------------------------------------------------------------------
168 // ParallelDefineClass flag does not apply to bootclass loader
169 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
170 if (class_loader.is_null()) return false;
171 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
172 return true;
173 }
174 return false;
175 }
176
177 // Returns true if the passed class loader is the builtin application class loader
178 // or a custom system class loader. A customer system class loader can be
179 // specified via -Djava.system.class.loader.
180 bool SystemDictionary::is_system_class_loader(oop class_loader) {
181 if (class_loader == NULL) {
182 return false;
183 }
184 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
185 oopDesc::equals(class_loader, _java_system_loader));
186 }
187
188 // Returns true if the passed class loader is the platform class loader.
189 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
190 if (class_loader == NULL) {
191 return false;
192 }
193 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
194 }
195
196 // ----------------------------------------------------------------------------
197 // Resolving of classes
198
199 // Forwards to resolve_or_null
200
201 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
202 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
203 if (HAS_PENDING_EXCEPTION || klass == NULL) {
204 // can return a null klass
205 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
206 }
207 return klass;
208 }
209
210 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
211 bool throw_error,
212 Klass* klass, TRAPS) {
213 if (HAS_PENDING_EXCEPTION) {
214 // If we have a pending exception we forward it to the caller, unless throw_error is true,
215 // in which case we have to check whether the pending exception is a ClassNotFoundException,
216 // and if so convert it to a NoClassDefFoundError
217 // And chain the original ClassNotFoundException
218 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
219 ResourceMark rm(THREAD);
220 assert(klass == NULL, "Should not have result with exception pending");
221 Handle e(THREAD, PENDING_EXCEPTION);
222 CLEAR_PENDING_EXCEPTION;
223 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
224 } else {
225 return NULL;
226 }
227 }
228 // Class not found, throw appropriate error or exception depending on value of throw_error
229 if (klass == NULL) {
230 ResourceMark rm(THREAD);
231 if (throw_error) {
232 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
233 } else {
234 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
235 }
236 }
237 return klass;
238 }
239
240
241 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
242 bool throw_error, TRAPS)
243 {
244 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
245 }
246
247
248 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
249
250 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
251 if (FieldType::is_array(class_name)) {
252 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
253 } else {
254 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
255 }
256 }
257
258 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
259 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
260 Handle class_loader,
261 Handle protection_domain,
262 TRAPS) {
263 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
264 if (FieldType::is_obj(class_name) || FieldType::is_valuetype(class_name)) {
265 ResourceMark rm(THREAD);
266 // Ignore wrapping L and ;. (and Q and ; for value types);
267 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
268 class_name->utf8_length() - 2);
269 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
270 } else {
271 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
272 }
273 }
274
275 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
276 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
277 }
278
279 // Forwards to resolve_instance_class_or_null
280
281 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
282 Handle class_loader,
283 Handle protection_domain,
284 TRAPS) {
285 assert(FieldType::is_array(class_name), "must be array");
286 Klass* k = NULL;
287 FieldArrayInfo fd;
288 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
289 // of this call
290 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
291 if (t == T_OBJECT || t == T_VALUETYPE) {
292 // naked oop "k" is OK here -- we assign back into it
293 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
294 class_loader,
295 protection_domain,
296 CHECK_NULL);
297 if (k != NULL) {
298 k = k->array_klass(fd.storage_props(), fd.dimension(), CHECK_NULL);
299 }
300 } else {
301 k = Universe::typeArrayKlassObj(t);
302 k = TypeArrayKlass::cast(k)->array_klass(fd.storage_props(), fd.dimension(), CHECK_NULL);
303 }
304 return k;
305 }
306
307 // Must be called for any super-class or super-interface resolution
308 // during class definition to allow class circularity checking
309 // super-interface callers:
310 // parse_interfaces - for defineClass & jvmtiRedefineClasses
311 // super-class callers:
312 // ClassFileParser - for defineClass & jvmtiRedefineClasses
313 // load_shared_class - while loading a class from shared archive
314 // resolve_instance_class_or_null:
315 // via: handle_parallel_super_load
316 // when resolving a class that has an existing placeholder with
317 // a saved superclass [i.e. a defineClass is currently in progress]
318 // if another thread is trying to resolve the class, it must do
319 // super-class checks on its own thread to catch class circularity
320 // This last call is critical in class circularity checking for cases
321 // where classloading is delegated to different threads and the
322 // classloader lock is released.
323 // Take the case: Base->Super->Base
324 // 1. If thread T1 tries to do a defineClass of class Base
325 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
326 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
327 // so it tries to load Super
328 // 3. If we load the class internally, or user classloader uses same thread
329 // loadClassFromxxx or defineClass via parseClassFile Super ...
330 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
331 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
332 // 3.4 calls resolve_super_or_fail Base
333 // 3.5 finds T1,Base -> throws class circularity
334 //OR 4. If T2 tries to resolve Super via defineClass Super ...
335 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
336 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
337 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
338 // 4.4 finds T2, Super -> throws class circularity
339 // Must be called, even if superclass is null, since this is
340 // where the placeholder entry is created which claims this
341 // thread is loading this class/classloader.
342 // Be careful when modifying this code: once you have run
343 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
344 // you need to find_and_remove it before returning.
345 // So be careful to not exit with a CHECK_ macro betweeen these calls.
346 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
347 Symbol* super_name,
348 Handle class_loader,
349 Handle protection_domain,
350 bool is_superclass,
351 TRAPS) {
352 assert(!FieldType::is_array(super_name), "invalid super class name");
353 #if INCLUDE_CDS
354 if (DumpSharedSpaces) {
355 // Special processing for handling UNREGISTERED shared classes.
356 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
357 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
358 if (k) {
359 return k;
360 }
361 }
362 #endif // INCLUDE_CDS
363
364 // Double-check, if child class is already loaded, just return super-class,interface
365 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
366 // dictionary.
367 // Make sure there's a placeholder for the *child* before resolving.
368 // Used as a claim that this thread is currently loading superclass/classloader
369 // Used here for ClassCircularity checks and also for heap verification
370 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
371 // Must check ClassCircularity before checking if super class is already loaded.
372 //
373 // We might not already have a placeholder if this child_name was
374 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
375 // the name of the class might not be known until the stream is actually
376 // parsed.
377 // Bugs 4643874, 4715493
378
379 ClassLoaderData* loader_data = class_loader_data(class_loader);
380 Dictionary* dictionary = loader_data->dictionary();
381 unsigned int d_hash = dictionary->compute_hash(child_name);
382 unsigned int p_hash = placeholders()->compute_hash(child_name);
383 int p_index = placeholders()->hash_to_index(p_hash);
384 // can't throw error holding a lock
385 bool child_already_loaded = false;
386 bool throw_circularity_error = false;
387 {
388 MutexLocker mu(SystemDictionary_lock, THREAD);
389 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
390 InstanceKlass* quicksuperk;
391 // to support // loading: if child done loading, just return superclass
392 // if super_name, & class_loader don't match:
393 // if initial define, SD update will give LinkageError
394 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
395 // so we don't throw an exception here.
396 // see: nsk redefclass014 & java.lang.instrument Instrument032
397 if ((childk != NULL ) && (is_superclass) &&
398 ((quicksuperk = childk->java_super()) != NULL) &&
399 ((quicksuperk->name() == super_name) &&
400 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
401 return quicksuperk;
402 } else {
403 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
404 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
405 throw_circularity_error = true;
406 }
407 }
408 if (!throw_circularity_error) {
409 // Be careful not to exit resolve_super
410 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
411 }
412 }
413 if (throw_circularity_error) {
414 ResourceMark rm(THREAD);
415 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
416 }
417
418 // java.lang.Object should have been found above
419 assert(super_name != NULL, "null super class for resolving");
420 // Resolve the super class or interface, check results on return
421 InstanceKlass* superk =
422 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
423 class_loader,
424 protection_domain,
425 THREAD);
426
427 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
428 // It is no longer necessary to keep the placeholder table alive until update_dictionary
429 // or error. GC used to walk the placeholder table as strong roots.
430 // The instanceKlass is kept alive because the class loader is on the stack,
431 // which keeps the loader_data alive, as well as all instanceKlasses in
432 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
433 {
434 MutexLocker mu(SystemDictionary_lock, THREAD);
435 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
436 SystemDictionary_lock->notify_all();
437 }
438 if (HAS_PENDING_EXCEPTION || superk == NULL) {
439 // can null superk
440 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
441 assert(k == NULL || k == superk, "must be");
442 if (k == NULL) {
443 superk = NULL;
444 }
445 }
446
447 return superk;
448 }
449
450 Klass* SystemDictionary::resolve_flattenable_field_or_fail(AllFieldStream* fs,
451 Handle class_loader,
452 Handle protection_domain,
453 bool throw_error,
454 TRAPS) {
455 Symbol* class_name = fs->signature()->fundamental_name(THREAD);
456 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
457 ClassLoaderData* loader_data = class_loader_data(class_loader);
458 unsigned int p_hash = placeholders()->compute_hash(class_name);
459 int p_index = placeholders()->hash_to_index(p_hash);
460 bool throw_circularity_error = false;
461 PlaceholderEntry* oldprobe;
462
463 {
464 MutexLocker mu(SystemDictionary_lock, THREAD);
465 oldprobe = placeholders()->get_entry(p_index, p_hash, class_name, loader_data);
466 if (oldprobe != NULL &&
467 oldprobe->check_seen_thread(THREAD, PlaceholderTable::FLATTENABLE_FIELD)) {
468 throw_circularity_error = true;
469
470 } else {
471 placeholders()->find_and_add(p_index, p_hash, class_name, loader_data,
472 PlaceholderTable::FLATTENABLE_FIELD, NULL, THREAD);
473 }
474 }
475
476 Klass* klass = NULL;
477 if (!throw_circularity_error) {
478 klass = SystemDictionary::resolve_or_fail(class_name, class_loader,
479 protection_domain, true, THREAD);
480 } else {
481 ResourceMark rm(THREAD);
482 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), class_name->as_C_string());
483 }
484
485 {
486 MutexLocker mu(SystemDictionary_lock, THREAD);
487 placeholders()->find_and_remove(p_index, p_hash, class_name, loader_data,
488 PlaceholderTable::FLATTENABLE_FIELD, THREAD);
489 }
490
491 class_name->decrement_refcount();
492 return klass;
493 }
494
495 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
496 Handle class_loader,
497 Handle protection_domain,
498 TRAPS) {
499 if(!has_checkPackageAccess()) return;
500
501 // Now we have to call back to java to check if the initating class has access
502 JavaValue result(T_VOID);
503 LogTarget(Debug, protectiondomain) lt;
504 if (lt.is_enabled()) {
505 ResourceMark rm;
506 // Print out trace information
507 LogStream ls(lt);
508 ls.print_cr("Checking package access");
509 if (class_loader() != NULL) {
510 ls.print("class loader: ");
511 class_loader()->print_value_on(&ls);
512 } else {
513 ls.print_cr("class loader: NULL");
514 }
515 if (protection_domain() != NULL) {
516 ls.print(" protection domain: ");
517 protection_domain()->print_value_on(&ls);
518 } else {
519 ls.print_cr(" protection domain: NULL");
520 }
521 ls.print(" loading: "); klass->print_value_on(&ls);
522 ls.cr();
523 }
524
525 // This handle and the class_loader handle passed in keeps this class from
526 // being unloaded through several GC points.
527 // The class_loader handle passed in is the initiating loader.
528 Handle mirror(THREAD, klass->java_mirror());
529
530 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
531 JavaCalls::call_special(&result,
532 class_loader,
533 system_loader,
534 vmSymbols::checkPackageAccess_name(),
535 vmSymbols::class_protectiondomain_signature(),
536 mirror,
537 protection_domain,
538 THREAD);
539
540 if (HAS_PENDING_EXCEPTION) {
541 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
542 } else {
543 log_debug(protectiondomain)("granted");
544 }
545
546 if (HAS_PENDING_EXCEPTION) return;
547
548 // If no exception has been thrown, we have validated the protection domain
549 // Insert the protection domain of the initiating class into the set.
550 {
551 ClassLoaderData* loader_data = class_loader_data(class_loader);
552 Dictionary* dictionary = loader_data->dictionary();
553
554 Symbol* kn = klass->name();
555 unsigned int d_hash = dictionary->compute_hash(kn);
556
557 MutexLocker mu(SystemDictionary_lock, THREAD);
558 int d_index = dictionary->hash_to_index(d_hash);
559 dictionary->add_protection_domain(d_index, d_hash, klass,
560 protection_domain, THREAD);
561 }
562 }
563
564 // We only get here if this thread finds that another thread
565 // has already claimed the placeholder token for the current operation,
566 // but that other thread either never owned or gave up the
567 // object lock
568 // Waits on SystemDictionary_lock to indicate placeholder table updated
569 // On return, caller must recheck placeholder table state
570 //
571 // We only get here if
572 // 1) custom classLoader, i.e. not bootstrap classloader
573 // 2) custom classLoader has broken the class loader objectLock
574 // so another thread got here in parallel
575 //
576 // lockObject must be held.
577 // Complicated dance due to lock ordering:
578 // Must first release the classloader object lock to
579 // allow initial definer to complete the class definition
580 // and to avoid deadlock
581 // Reclaim classloader lock object with same original recursion count
582 // Must release SystemDictionary_lock after notify, since
583 // class loader lock must be claimed before SystemDictionary_lock
584 // to prevent deadlocks
585 //
586 // The notify allows applications that did an untimed wait() on
587 // the classloader object lock to not hang.
588 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
589 assert_lock_strong(SystemDictionary_lock);
590
591 bool calledholdinglock
592 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
593 assert(calledholdinglock,"must hold lock for notify");
594 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
595 ObjectSynchronizer::notifyall(lockObject, THREAD);
596 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
597 SystemDictionary_lock->wait();
598 SystemDictionary_lock->unlock();
599 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
600 SystemDictionary_lock->lock();
601 }
602
603 // If the class in is in the placeholder table, class loading is in progress
604 // For cases where the application changes threads to load classes, it
605 // is critical to ClassCircularity detection that we try loading
606 // the superclass on the same thread internally, so we do parallel
607 // super class loading here.
608 // This also is critical in cases where the original thread gets stalled
609 // even in non-circularity situations.
610 // Note: must call resolve_super_or_fail even if null super -
611 // to force placeholder entry creation for this class for circularity detection
612 // Caller must check for pending exception
613 // Returns non-null Klass* if other thread has completed load
614 // and we are done,
615 // If return null Klass* and no pending exception, the caller must load the class
616 InstanceKlass* SystemDictionary::handle_parallel_super_load(
617 Symbol* name, Symbol* superclassname, Handle class_loader,
618 Handle protection_domain, Handle lockObject, TRAPS) {
619
620 ClassLoaderData* loader_data = class_loader_data(class_loader);
621 Dictionary* dictionary = loader_data->dictionary();
622 unsigned int d_hash = dictionary->compute_hash(name);
623 unsigned int p_hash = placeholders()->compute_hash(name);
624 int p_index = placeholders()->hash_to_index(p_hash);
625
626 // superk is not used, resolve_super called for circularity check only
627 // This code is reached in two situations. One if this thread
628 // is loading the same class twice (e.g. ClassCircularity, or
629 // java.lang.instrument).
630 // The second is if another thread started the resolve_super first
631 // and has not yet finished.
632 // In both cases the original caller will clean up the placeholder
633 // entry on error.
634 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
635 superclassname,
636 class_loader,
637 protection_domain,
638 true,
639 CHECK_NULL);
640
641 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
642 // Serial class loaders and bootstrap classloader do wait for superclass loads
643 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
644 MutexLocker mu(SystemDictionary_lock, THREAD);
645 // Check if classloading completed while we were loading superclass or waiting
646 return find_class(d_hash, name, dictionary);
647 }
648
649 // must loop to both handle other placeholder updates
650 // and spurious notifications
651 bool super_load_in_progress = true;
652 PlaceholderEntry* placeholder;
653 while (super_load_in_progress) {
654 MutexLocker mu(SystemDictionary_lock, THREAD);
655 // Check if classloading completed while we were loading superclass or waiting
656 InstanceKlass* check = find_class(d_hash, name, dictionary);
657 if (check != NULL) {
658 // Klass is already loaded, so just return it
659 return check;
660 } else {
661 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
662 if (placeholder && placeholder->super_load_in_progress() ){
663 // We only get here if the application has released the
664 // classloader lock when another thread was in the middle of loading a
665 // superclass/superinterface for this class, and now
666 // this thread is also trying to load this class.
667 // To minimize surprises, the first thread that started to
668 // load a class should be the one to complete the loading
669 // with the classfile it initially expected.
670 // This logic has the current thread wait once it has done
671 // all the superclass/superinterface loading it can, until
672 // the original thread completes the class loading or fails
673 // If it completes we will use the resulting InstanceKlass
674 // which we will find below in the systemDictionary.
675 // We also get here for parallel bootstrap classloader
676 if (class_loader.is_null()) {
677 SystemDictionary_lock->wait();
678 } else {
679 double_lock_wait(lockObject, THREAD);
680 }
681 } else {
682 // If not in SD and not in PH, other thread's load must have failed
683 super_load_in_progress = false;
684 }
685 }
686 }
687 return NULL;
688 }
689
690 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
691 assert(event != NULL, "invariant");
692 assert(k != NULL, "invariant");
693 assert(event->should_commit(), "invariant");
694 event->set_loadedClass(k);
695 event->set_definingClassLoader(k->class_loader_data());
696 event->set_initiatingClassLoader(init_cld);
697 event->commit();
698 }
699
700
701 // Be careful when modifying this code: once you have run
702 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
703 // you need to find_and_remove it before returning.
704 // So be careful to not exit with a CHECK_ macro betweeen these calls.
705 //
706 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
707 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
708 Handle class_loader,
709 Handle protection_domain,
710 TRAPS) {
711 assert(name != NULL && !FieldType::is_array(name) &&
712 !FieldType::is_obj(name) && !FieldType::is_valuetype(name), "invalid class name");
713
714 EventClassLoad class_load_start_event;
715
716 HandleMark hm(THREAD);
717
718 // Fix for 4474172; see evaluation for more details
719 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
720 ClassLoaderData* loader_data = register_loader(class_loader);
721 Dictionary* dictionary = loader_data->dictionary();
722 unsigned int d_hash = dictionary->compute_hash(name);
723
724 // Do lookup to see if class already exist and the protection domain
725 // has the right access
726 // This call uses find which checks protection domain already matches
727 // All subsequent calls use find_class, and set has_loaded_class so that
728 // before we return a result we call out to java to check for valid protection domain
729 // to allow returning the Klass* and add it to the pd_set if it is valid
730 {
731 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
732 if (probe != NULL) return probe;
733 }
734
735 // Non-bootstrap class loaders will call out to class loader and
736 // define via jvm/jni_DefineClass which will acquire the
737 // class loader object lock to protect against multiple threads
738 // defining the class in parallel by accident.
739 // This lock must be acquired here so the waiter will find
740 // any successful result in the SystemDictionary and not attempt
741 // the define.
742 // ParallelCapable Classloaders and the bootstrap classloader
743 // do not acquire lock here.
744 bool DoObjectLock = true;
745 if (is_parallelCapable(class_loader)) {
746 DoObjectLock = false;
747 }
748
749 unsigned int p_hash = placeholders()->compute_hash(name);
750 int p_index = placeholders()->hash_to_index(p_hash);
751
752 // Class is not in SystemDictionary so we have to do loading.
753 // Make sure we are synchronized on the class loader before we proceed
754 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
755 check_loader_lock_contention(lockObject, THREAD);
756 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
757
758 // Check again (after locking) if class already exist in SystemDictionary
759 bool class_has_been_loaded = false;
760 bool super_load_in_progress = false;
761 bool havesupername = false;
762 InstanceKlass* k = NULL;
763 PlaceholderEntry* placeholder;
764 Symbol* superclassname = NULL;
765
766 assert(THREAD->can_call_java(),
767 "can not load classes with compiler thread: class=%s, classloader=%s",
768 name->as_C_string(),
769 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
770 {
771 MutexLocker mu(SystemDictionary_lock, THREAD);
772 InstanceKlass* check = find_class(d_hash, name, dictionary);
773 if (check != NULL) {
774 // InstanceKlass is already loaded, so just return it
775 class_has_been_loaded = true;
776 k = check;
777 } else {
778 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
779 if (placeholder && placeholder->super_load_in_progress()) {
780 super_load_in_progress = true;
781 if (placeholder->havesupername() == true) {
782 superclassname = placeholder->supername();
783 havesupername = true;
784 }
785 }
786 }
787 }
788
789 // If the class is in the placeholder table, class loading is in progress
790 if (super_load_in_progress && havesupername==true) {
791 k = handle_parallel_super_load(name,
792 superclassname,
793 class_loader,
794 protection_domain,
795 lockObject, THREAD);
796 if (HAS_PENDING_EXCEPTION) {
797 return NULL;
798 }
799 if (k != NULL) {
800 class_has_been_loaded = true;
801 }
802 }
803
804 bool throw_circularity_error = false;
805 if (!class_has_been_loaded) {
806 bool load_instance_added = false;
807
808 // add placeholder entry to record loading instance class
809 // Five cases:
810 // All cases need to prevent modifying bootclasssearchpath
811 // in parallel with a classload of same classname
812 // Redefineclasses uses existence of the placeholder for the duration
813 // of the class load to prevent concurrent redefinition of not completely
814 // defined classes.
815 // case 1. traditional classloaders that rely on the classloader object lock
816 // - no other need for LOAD_INSTANCE
817 // case 2. traditional classloaders that break the classloader object lock
818 // as a deadlock workaround. Detection of this case requires that
819 // this check is done while holding the classloader object lock,
820 // and that lock is still held when calling classloader's loadClass.
821 // For these classloaders, we ensure that the first requestor
822 // completes the load and other requestors wait for completion.
823 // case 3. Bootstrap classloader - don't own objectLocker
824 // This classloader supports parallelism at the classloader level,
825 // but only allows a single load of a class/classloader pair.
826 // No performance benefit and no deadlock issues.
827 // case 4. parallelCapable user level classloaders - without objectLocker
828 // Allow parallel classloading of a class/classloader pair
829
830 {
831 MutexLocker mu(SystemDictionary_lock, THREAD);
832 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
833 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
834 if (oldprobe) {
835 // only need check_seen_thread once, not on each loop
836 // 6341374 java/lang/Instrument with -Xcomp
837 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
838 throw_circularity_error = true;
839 } else {
840 // case 1: traditional: should never see load_in_progress.
841 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
842
843 // case 3: bootstrap classloader: prevent futile classloading,
844 // wait on first requestor
845 if (class_loader.is_null()) {
846 SystemDictionary_lock->wait();
847 } else {
848 // case 2: traditional with broken classloader lock. wait on first
849 // requestor.
850 double_lock_wait(lockObject, THREAD);
851 }
852 // Check if classloading completed while we were waiting
853 InstanceKlass* check = find_class(d_hash, name, dictionary);
854 if (check != NULL) {
855 // Klass is already loaded, so just return it
856 k = check;
857 class_has_been_loaded = true;
858 }
859 // check if other thread failed to load and cleaned up
860 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
861 }
862 }
863 }
864 }
865 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
866 // case 4: parallelCapable: allow competing threads to try
867 // LOAD_INSTANCE in parallel
868
869 if (!throw_circularity_error && !class_has_been_loaded) {
870 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
871 load_instance_added = true;
872 // For class loaders that do not acquire the classloader object lock,
873 // if they did not catch another thread holding LOAD_INSTANCE,
874 // need a check analogous to the acquire ObjectLocker/find_class
875 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
876 // one final check if the load has already completed
877 // class loaders holding the ObjectLock shouldn't find the class here
878 InstanceKlass* check = find_class(d_hash, name, dictionary);
879 if (check != NULL) {
880 // Klass is already loaded, so return it after checking/adding protection domain
881 k = check;
882 class_has_been_loaded = true;
883 }
884 }
885 }
886
887 // must throw error outside of owning lock
888 if (throw_circularity_error) {
889 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
890 ResourceMark rm(THREAD);
891 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
892 }
893
894 if (!class_has_been_loaded) {
895
896 // Do actual loading
897 k = load_instance_class(name, class_loader, THREAD);
898
899 // If everything was OK (no exceptions, no null return value), and
900 // class_loader is NOT the defining loader, do a little more bookkeeping.
901 if (!HAS_PENDING_EXCEPTION && k != NULL &&
902 !oopDesc::equals(k->class_loader(), class_loader())) {
903
904 check_constraints(d_hash, k, class_loader, false, THREAD);
905
906 // Need to check for a PENDING_EXCEPTION again; check_constraints
907 // can throw but we may have to remove entry from the placeholder table below.
908 if (!HAS_PENDING_EXCEPTION) {
909 // Record dependency for non-parent delegation.
910 // This recording keeps the defining class loader of the klass (k) found
911 // from being unloaded while the initiating class loader is loaded
912 // even if the reference to the defining class loader is dropped
913 // before references to the initiating class loader.
914 loader_data->record_dependency(k);
915
916 { // Grabbing the Compile_lock prevents systemDictionary updates
917 // during compilations.
918 MutexLocker mu(Compile_lock, THREAD);
919 update_dictionary(d_hash, p_index, p_hash,
920 k, class_loader, THREAD);
921 }
922
923 if (JvmtiExport::should_post_class_load()) {
924 Thread *thread = THREAD;
925 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
926 JvmtiExport::post_class_load((JavaThread *) thread, k);
927 }
928 }
929 }
930 } // load_instance_class
931
932 if (load_instance_added == true) {
933 // clean up placeholder entries for LOAD_INSTANCE success or error
934 // This brackets the SystemDictionary updates for both defining
935 // and initiating loaders
936 MutexLocker mu(SystemDictionary_lock, THREAD);
937 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
938 SystemDictionary_lock->notify_all();
939 }
940 }
941
942 if (HAS_PENDING_EXCEPTION || k == NULL) {
943 return NULL;
944 }
945 if (class_load_start_event.should_commit()) {
946 post_class_load_event(&class_load_start_event, k, loader_data);
947 }
948 #ifdef ASSERT
949 {
950 ClassLoaderData* loader_data = k->class_loader_data();
951 MutexLocker mu(SystemDictionary_lock, THREAD);
952 InstanceKlass* kk = find_class(name, loader_data);
953 assert(kk == k, "should be present in dictionary");
954 }
955 #endif
956
957 // return if the protection domain in NULL
958 if (protection_domain() == NULL) return k;
959
960 // Check the protection domain has the right access
961 if (dictionary->is_valid_protection_domain(d_hash, name,
962 protection_domain)) {
963 return k;
964 }
965
966 // Verify protection domain. If it fails an exception is thrown
967 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
968
969 return k;
970 }
971
972
973 // This routine does not lock the system dictionary.
974 //
975 // Since readers don't hold a lock, we must make sure that system
976 // dictionary entries are only removed at a safepoint (when only one
977 // thread is running), and are added to in a safe way (all links must
978 // be updated in an MT-safe manner).
979 //
980 // Callers should be aware that an entry could be added just after
981 // _dictionary->bucket(index) is read here, so the caller will not see
982 // the new entry.
983
984 Klass* SystemDictionary::find(Symbol* class_name,
985 Handle class_loader,
986 Handle protection_domain,
987 TRAPS) {
988
989 // The result of this call should be consistent with the result
990 // of the call to resolve_instance_class_or_null().
991 // See evaluation 6790209 and 4474172 for more details.
992 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
993 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
994
995 if (loader_data == NULL) {
996 // If the ClassLoaderData has not been setup,
997 // then the class loader has no entries in the dictionary.
998 return NULL;
999 }
1000
1001 Dictionary* dictionary = loader_data->dictionary();
1002 unsigned int d_hash = dictionary->compute_hash(class_name);
1003 return dictionary->find(d_hash, class_name,
1004 protection_domain);
1005 }
1006
1007
1008 // Look for a loaded instance or array klass by name. Do not do any loading.
1009 // return NULL in case of error.
1010 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1011 Handle class_loader,
1012 Handle protection_domain,
1013 TRAPS) {
1014 Klass* k = NULL;
1015 assert(class_name != NULL, "class name must be non NULL");
1016
1017 if (FieldType::is_array(class_name)) {
1018 // The name refers to an array. Parse the name.
1019 // dimension and object_key in FieldArrayInfo are assigned as a
1020 // side-effect of this call
1021 FieldArrayInfo fd;
1022 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1023 if (t != T_OBJECT && t != T_VALUETYPE) {
1024 k = Universe::typeArrayKlassObj(t);
1025 } else {
1026 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1027 }
1028 if (k != NULL) {
1029 k = k->array_klass_or_null(fd.storage_props(), fd.dimension());
1030 }
1031 } else {
1032 k = find(class_name, class_loader, protection_domain, THREAD);
1033 }
1034 return k;
1035 }
1036
1037 // Note: this method is much like resolve_from_stream, but
1038 // does not publish the classes via the SystemDictionary.
1039 // Handles unsafe_DefineAnonymousClass and redefineclasses
1040 // RedefinedClasses do not add to the class hierarchy
1041 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1042 Handle class_loader,
1043 Handle protection_domain,
1044 ClassFileStream* st,
1045 const InstanceKlass* unsafe_anonymous_host,
1046 GrowableArray<Handle>* cp_patches,
1047 TRAPS) {
1048
1049 EventClassLoad class_load_start_event;
1050
1051 ClassLoaderData* loader_data;
1052 if (unsafe_anonymous_host != NULL) {
1053 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1054 // as the unsafe_anonymous_host
1055 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1056 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1057 } else {
1058 loader_data = ClassLoaderData::class_loader_data(class_loader());
1059 }
1060
1061 assert(st != NULL, "invariant");
1062 assert(st->need_verify(), "invariant");
1063
1064 // Parse stream and create a klass.
1065 // Note that we do this even though this klass might
1066 // already be present in the SystemDictionary, otherwise we would not
1067 // throw potential ClassFormatErrors.
1068
1069 InstanceKlass* k = KlassFactory::create_from_stream(st,
1070 class_name,
1071 loader_data,
1072 protection_domain,
1073 unsafe_anonymous_host,
1074 cp_patches,
1075 CHECK_NULL);
1076
1077 if (unsafe_anonymous_host != NULL && k != NULL) {
1078 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1079 // so that they can be unloaded when the mirror is no longer referenced.
1080 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1081
1082 {
1083 MutexLocker mu_r(Compile_lock, THREAD);
1084
1085 // Add to class hierarchy, initialize vtables, and do possible
1086 // deoptimizations.
1087 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1088
1089 // But, do not add to dictionary.
1090
1091 // compiled code dependencies need to be validated anyway
1092 notice_modification();
1093 }
1094
1095 // Rewrite and patch constant pool here.
1096 k->link_class(CHECK_NULL);
1097 if (cp_patches != NULL) {
1098 k->constants()->patch_resolved_references(cp_patches);
1099 }
1100
1101 // If it's anonymous, initialize it now, since nobody else will.
1102 k->eager_initialize(CHECK_NULL);
1103
1104 // notify jvmti
1105 if (JvmtiExport::should_post_class_load()) {
1106 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1107 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1108 }
1109 if (class_load_start_event.should_commit()) {
1110 post_class_load_event(&class_load_start_event, k, loader_data);
1111 }
1112 }
1113 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1114 "cp_patches only found with unsafe_anonymous_host");
1115
1116 return k;
1117 }
1118
1119 // Add a klass to the system from a stream (called by jni_DefineClass and
1120 // JVM_DefineClass).
1121 // Note: class_name can be NULL. In that case we do not know the name of
1122 // the class until we have parsed the stream.
1123
1124 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1125 Handle class_loader,
1126 Handle protection_domain,
1127 ClassFileStream* st,
1128 TRAPS) {
1129
1130 HandleMark hm(THREAD);
1131
1132 // Classloaders that support parallelism, e.g. bootstrap classloader,
1133 // do not acquire lock here
1134 bool DoObjectLock = true;
1135 if (is_parallelCapable(class_loader)) {
1136 DoObjectLock = false;
1137 }
1138
1139 ClassLoaderData* loader_data = register_loader(class_loader);
1140
1141 // Make sure we are synchronized on the class loader before we proceed
1142 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1143 check_loader_lock_contention(lockObject, THREAD);
1144 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1145
1146 assert(st != NULL, "invariant");
1147
1148 // Parse the stream and create a klass.
1149 // Note that we do this even though this klass might
1150 // already be present in the SystemDictionary, otherwise we would not
1151 // throw potential ClassFormatErrors.
1152 InstanceKlass* k = NULL;
1153
1154 #if INCLUDE_CDS
1155 if (!DumpSharedSpaces) {
1156 k = SystemDictionaryShared::lookup_from_stream(class_name,
1157 class_loader,
1158 protection_domain,
1159 st,
1160 CHECK_NULL);
1161 }
1162 #endif
1163
1164 if (k == NULL) {
1165 if (st->buffer() == NULL) {
1166 return NULL;
1167 }
1168 k = KlassFactory::create_from_stream(st,
1169 class_name,
1170 loader_data,
1171 protection_domain,
1172 NULL, // unsafe_anonymous_host
1173 NULL, // cp_patches
1174 CHECK_NULL);
1175 }
1176
1177 assert(k != NULL, "no klass created");
1178 Symbol* h_name = k->name();
1179 assert(class_name == NULL || class_name == h_name, "name mismatch");
1180
1181 // Add class just loaded
1182 // If a class loader supports parallel classloading handle parallel define requests
1183 // find_or_define_instance_class may return a different InstanceKlass
1184 if (is_parallelCapable(class_loader)) {
1185 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1186 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1187 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1188 assert(defined_k != NULL, "Should have a klass if there's no exception");
1189 loader_data->add_to_deallocate_list(k);
1190 k = defined_k;
1191 }
1192 } else {
1193 define_instance_class(k, THREAD);
1194 }
1195
1196 // If defining the class throws an exception register 'k' for cleanup.
1197 if (HAS_PENDING_EXCEPTION) {
1198 assert(k != NULL, "Must have an instance klass here!");
1199 loader_data->add_to_deallocate_list(k);
1200 return NULL;
1201 }
1202
1203 // Make sure we have an entry in the SystemDictionary on success
1204 debug_only( {
1205 MutexLocker mu(SystemDictionary_lock, THREAD);
1206
1207 Klass* check = find_class(h_name, k->class_loader_data());
1208 assert(check == k, "should be present in the dictionary");
1209 } );
1210
1211 return k;
1212 }
1213
1214 #if INCLUDE_CDS
1215 // Load a class for boot loader from the shared spaces. This also
1216 // forces the super class and all interfaces to be loaded.
1217 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1218 TRAPS) {
1219 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1220 if (ik != NULL && ik->is_shared_boot_class()) {
1221 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1222 }
1223 return NULL;
1224 }
1225
1226 // Check if a shared class can be loaded by the specific classloader:
1227 //
1228 // NULL classloader:
1229 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1230 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1231 // be defined in an unnamed module.
1232 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1233 InstanceKlass* ik,
1234 Handle class_loader, TRAPS) {
1235 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1236 "Cannot use sharing if java.base is patched");
1237 ResourceMark rm;
1238 int path_index = ik->shared_classpath_index();
1239 ClassLoaderData* loader_data = class_loader_data(class_loader);
1240 if (path_index < 0) {
1241 // path_index < 0 indicates that the class is intended for a custom loader
1242 // and should not be loaded by boot/platform/app loaders
1243 if (loader_data->is_builtin_class_loader_data()) {
1244 return false;
1245 } else {
1246 return true;
1247 }
1248 }
1249 SharedClassPathEntry* ent =
1250 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1251 if (!Universe::is_module_initialized()) {
1252 assert(ent != NULL && ent->is_modules_image(),
1253 "Loading non-bootstrap classes before the module system is initialized");
1254 assert(class_loader.is_null(), "sanity");
1255 return true;
1256 }
1257 // Get the pkg_entry from the classloader
1258 TempNewSymbol pkg_name = NULL;
1259 PackageEntry* pkg_entry = NULL;
1260 ModuleEntry* mod_entry = NULL;
1261 const char* pkg_string = NULL;
1262 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1263 if (pkg_name != NULL) {
1264 pkg_string = pkg_name->as_C_string();
1265 if (loader_data != NULL) {
1266 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1267 }
1268 if (pkg_entry != NULL) {
1269 mod_entry = pkg_entry->module();
1270 }
1271 }
1272
1273 // If the archived class is from a module that has been patched at runtime,
1274 // the class cannot be loaded from the archive.
1275 if (mod_entry != NULL && mod_entry->is_patched()) {
1276 return false;
1277 }
1278
1279 if (class_loader.is_null()) {
1280 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1281 // The NULL classloader can load archived class originated from the
1282 // "modules" jimage and the -Xbootclasspath/a. For class from the
1283 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1284 // by the NULL classloader.
1285 if (mod_entry != NULL) {
1286 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1287 // ModuleEntry's location agrees with the archived class' origination.
1288 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1289 return true; // Module class from the "module" jimage
1290 }
1291 }
1292
1293 // If the archived class is not from the "module" jimage, the class can be
1294 // loaded by the NULL classloader if
1295 //
1296 // 1. the class is from the unamed package
1297 // 2. or, the class is not from a module defined in the NULL classloader
1298 // 3. or, the class is from an unamed module
1299 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1300 // the class is from the -Xbootclasspath/a
1301 if (pkg_string == NULL ||
1302 pkg_entry == NULL ||
1303 pkg_entry->in_unnamed_module()) {
1304 assert(mod_entry == NULL ||
1305 mod_entry == loader_data->unnamed_module(),
1306 "the unnamed module is not defined in the classloader");
1307 return true;
1308 }
1309 }
1310 return false;
1311 } else {
1312 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1313 ik, class_loader, pkg_string, pkg_name,
1314 pkg_entry, mod_entry, CHECK_(false));
1315 return res;
1316 }
1317 }
1318
1319 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1320 Handle class_loader,
1321 Handle protection_domain,
1322 const ClassFileStream *cfs,
1323 TRAPS) {
1324
1325 if (ik != NULL) {
1326 Symbol* class_name = ik->name();
1327
1328 bool visible = is_shared_class_visible(
1329 class_name, ik, class_loader, CHECK_NULL);
1330 if (!visible) {
1331 return NULL;
1332 }
1333
1334 // Resolve the superclass and interfaces. They must be the same
1335 // as in dump time, because the layout of <ik> depends on
1336 // the specific layout of ik->super() and ik->local_interfaces().
1337 //
1338 // If unexpected superclass or interfaces are found, we cannot
1339 // load <ik> from the shared archive.
1340
1341 if (ik->super() != NULL) {
1342 Symbol* cn = ik->super()->name();
1343 Klass *s = resolve_super_or_fail(class_name, cn,
1344 class_loader, protection_domain, true, CHECK_NULL);
1345 if (s != ik->super()) {
1346 // The dynamically resolved super class is not the same as the one we used during dump time,
1347 // so we cannot use ik.
1348 return NULL;
1349 } else {
1350 assert(s->is_shared(), "must be");
1351 }
1352 }
1353
1354 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1355 int num_interfaces = interfaces->length();
1356 for (int index = 0; index < num_interfaces; index++) {
1357 InstanceKlass* k = interfaces->at(index);
1358 Symbol* name = k->name();
1359 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1360 if (k != i) {
1361 // The dynamically resolved interface class is not the same as the one we used during dump time,
1362 // so we cannot use ik.
1363 return NULL;
1364 } else {
1365 assert(i->is_shared(), "must be");
1366 }
1367 }
1368
1369 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1370 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1371 if (new_ik != NULL) {
1372 // The class is changed by CFLH. Return the new class. The shared class is
1373 // not used.
1374 return new_ik;
1375 }
1376
1377 // Adjust methods to recover missing data. They need addresses for
1378 // interpreter entry points and their default native method address
1379 // must be reset.
1380
1381 // Updating methods must be done under a lock so multiple
1382 // threads don't update these in parallel
1383 //
1384 // Shared classes are all currently loaded by either the bootstrap or
1385 // internal parallel class loaders, so this will never cause a deadlock
1386 // on a custom class loader lock.
1387
1388 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1389 {
1390 HandleMark hm(THREAD);
1391 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1392 check_loader_lock_contention(lockObject, THREAD);
1393 ObjectLocker ol(lockObject, THREAD, true);
1394 // prohibited package check assumes all classes loaded from archive call
1395 // restore_unshareable_info which calls ik->set_package()
1396 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1397 }
1398
1399 ik->print_class_load_logging(loader_data, NULL, NULL);
1400
1401 // For boot loader, ensure that GetSystemPackage knows that a class in this
1402 // package was loaded.
1403 if (class_loader.is_null()) {
1404 int path_index = ik->shared_classpath_index();
1405 ResourceMark rm;
1406 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1407 }
1408
1409 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1410 // Only dump the classes that can be stored into CDS archive
1411 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1412 ResourceMark rm(THREAD);
1413 classlist_file->print_cr("%s", ik->name()->as_C_string());
1414 classlist_file->flush();
1415 }
1416 }
1417
1418 // notify a class loaded from shared object
1419 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1420
1421 ik->set_has_passed_fingerprint_check(false);
1422 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1423 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1424 uint64_t cds_fp = ik->get_stored_fingerprint();
1425 if (aot_fp != 0 && aot_fp == cds_fp) {
1426 // This class matches with a class saved in an AOT library
1427 ik->set_has_passed_fingerprint_check(true);
1428 } else {
1429 ResourceMark rm;
1430 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1431 }
1432 }
1433 }
1434 return ik;
1435 }
1436 #endif // INCLUDE_CDS
1437
1438 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1439
1440 if (class_loader.is_null()) {
1441 ResourceMark rm;
1442 PackageEntry* pkg_entry = NULL;
1443 bool search_only_bootloader_append = false;
1444 ClassLoaderData *loader_data = class_loader_data(class_loader);
1445
1446 // Find the package in the boot loader's package entry table.
1447 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1448 if (pkg_name != NULL) {
1449 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1450 }
1451
1452 // Prior to attempting to load the class, enforce the boot loader's
1453 // visibility boundaries.
1454 if (!Universe::is_module_initialized()) {
1455 // During bootstrapping, prior to module initialization, any
1456 // class attempting to be loaded must be checked against the
1457 // java.base packages in the boot loader's PackageEntryTable.
1458 // No class outside of java.base is allowed to be loaded during
1459 // this bootstrapping window.
1460 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1461 // Class is either in the unnamed package or in
1462 // a named package within the unnamed module. Either
1463 // case is outside of java.base, do not attempt to
1464 // load the class post java.base definition. If
1465 // java.base has not been defined, let the class load
1466 // and its package will be checked later by
1467 // ModuleEntryTable::verify_javabase_packages.
1468 if (ModuleEntryTable::javabase_defined()) {
1469 return NULL;
1470 }
1471 } else {
1472 // Check that the class' package is defined within java.base.
1473 ModuleEntry* mod_entry = pkg_entry->module();
1474 Symbol* mod_entry_name = mod_entry->name();
1475 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1476 return NULL;
1477 }
1478 }
1479 } else {
1480 // After the module system has been initialized, check if the class'
1481 // package is in a module defined to the boot loader.
1482 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1483 // Class is either in the unnamed package, in a named package
1484 // within a module not defined to the boot loader or in a
1485 // a named package within the unnamed module. In all cases,
1486 // limit visibility to search for the class only in the boot
1487 // loader's append path.
1488 search_only_bootloader_append = true;
1489 }
1490 }
1491
1492 // Prior to bootstrapping's module initialization, never load a class outside
1493 // of the boot loader's module path
1494 assert(Universe::is_module_initialized() ||
1495 !search_only_bootloader_append,
1496 "Attempt to load a class outside of boot loader's module path");
1497
1498 // Search for classes in the CDS archive.
1499 InstanceKlass* k = NULL;
1500 {
1501 #if INCLUDE_CDS
1502 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1503 k = load_shared_boot_class(class_name, THREAD);
1504 #endif
1505 }
1506
1507 if (k == NULL) {
1508 // Use VM class loader
1509 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1510 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1511 }
1512
1513 // find_or_define_instance_class may return a different InstanceKlass
1514 if (k != NULL) {
1515 InstanceKlass* defined_k =
1516 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1517 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1518 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1519 assert(defined_k != NULL, "Should have a klass if there's no exception");
1520 loader_data->add_to_deallocate_list(k);
1521 k = defined_k;
1522 } else if (HAS_PENDING_EXCEPTION) {
1523 loader_data->add_to_deallocate_list(k);
1524 return NULL;
1525 }
1526 }
1527 return k;
1528 } else {
1529 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1530 ResourceMark rm(THREAD);
1531
1532 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1533 JavaThread* jt = (JavaThread*) THREAD;
1534
1535 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1536 ClassLoader::perf_app_classload_selftime(),
1537 ClassLoader::perf_app_classload_count(),
1538 jt->get_thread_stat()->perf_recursion_counts_addr(),
1539 jt->get_thread_stat()->perf_timers_addr(),
1540 PerfClassTraceTime::CLASS_LOAD);
1541
1542 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1543 // Translate to external class name format, i.e., convert '/' chars to '.'
1544 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1545
1546 JavaValue result(T_OBJECT);
1547
1548 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1549
1550 // Call public unsynchronized loadClass(String) directly for all class loaders.
1551 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1552 // acquire a class-name based lock rather than the class loader object lock.
1553 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1554 JavaCalls::call_virtual(&result,
1555 class_loader,
1556 spec_klass,
1557 vmSymbols::loadClass_name(),
1558 vmSymbols::string_class_signature(),
1559 string,
1560 CHECK_NULL);
1561
1562 assert(result.get_type() == T_OBJECT, "just checking");
1563 oop obj = (oop) result.get_jobject();
1564
1565 // Primitive classes return null since forName() can not be
1566 // used to obtain any of the Class objects representing primitives or void
1567 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1568 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1569 // For user defined Java class loaders, check that the name returned is
1570 // the same as that requested. This check is done for the bootstrap
1571 // loader when parsing the class file.
1572 if (class_name == k->name()) {
1573 return k;
1574 }
1575 }
1576 // Class is not found or has the wrong name, return NULL
1577 return NULL;
1578 }
1579 }
1580
1581 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1582 EventClassDefine event;
1583 if (event.should_commit()) {
1584 event.set_definedClass(k);
1585 event.set_definingClassLoader(def_cld);
1586 event.commit();
1587 }
1588 }
1589
1590 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1591
1592 HandleMark hm(THREAD);
1593 ClassLoaderData* loader_data = k->class_loader_data();
1594 Handle class_loader_h(THREAD, loader_data->class_loader());
1595
1596 // for bootstrap and other parallel classloaders don't acquire lock,
1597 // use placeholder token
1598 // If a parallelCapable class loader calls define_instance_class instead of
1599 // find_or_define_instance_class to get here, we have a timing
1600 // hole with systemDictionary updates and check_constraints
1601 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1602 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1603 compute_loader_lock_object(class_loader_h, THREAD)),
1604 "define called without lock");
1605 }
1606
1607 // Check class-loading constraints. Throw exception if violation is detected.
1608 // Grabs and releases SystemDictionary_lock
1609 // The check_constraints/find_class call and update_dictionary sequence
1610 // must be "atomic" for a specific class/classloader pair so we never
1611 // define two different instanceKlasses for that class/classloader pair.
1612 // Existing classloaders will call define_instance_class with the
1613 // classloader lock held
1614 // Parallel classloaders will call find_or_define_instance_class
1615 // which will require a token to perform the define class
1616 Symbol* name_h = k->name();
1617 Dictionary* dictionary = loader_data->dictionary();
1618 unsigned int d_hash = dictionary->compute_hash(name_h);
1619 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1620
1621 // Register class just loaded with class loader (placed in Vector)
1622 // Note we do this before updating the dictionary, as this can
1623 // fail with an OutOfMemoryError (if it does, we will *not* put this
1624 // class in the dictionary and will not update the class hierarchy).
1625 // JVMTI FollowReferences needs to find the classes this way.
1626 if (k->class_loader() != NULL) {
1627 methodHandle m(THREAD, Universe::loader_addClass_method());
1628 JavaValue result(T_VOID);
1629 JavaCallArguments args(class_loader_h);
1630 args.push_oop(Handle(THREAD, k->java_mirror()));
1631 JavaCalls::call(&result, m, &args, CHECK);
1632 }
1633
1634 // Add the new class. We need recompile lock during update of CHA.
1635 {
1636 unsigned int p_hash = placeholders()->compute_hash(name_h);
1637 int p_index = placeholders()->hash_to_index(p_hash);
1638
1639 MutexLocker mu_r(Compile_lock, THREAD);
1640
1641 // Add to class hierarchy, initialize vtables, and do possible
1642 // deoptimizations.
1643 add_to_hierarchy(k, CHECK); // No exception, but can block
1644
1645 // Add to systemDictionary - so other classes can see it.
1646 // Grabs and releases SystemDictionary_lock
1647 update_dictionary(d_hash, p_index, p_hash,
1648 k, class_loader_h, THREAD);
1649 }
1650 k->eager_initialize(THREAD);
1651
1652 // notify jvmti
1653 if (JvmtiExport::should_post_class_load()) {
1654 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1655 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1656
1657 }
1658 post_class_define_event(k, loader_data);
1659 }
1660
1661 // Support parallel classloading
1662 // All parallel class loaders, including bootstrap classloader
1663 // lock a placeholder entry for this class/class_loader pair
1664 // to allow parallel defines of different classes for this class loader
1665 // With AllowParallelDefine flag==true, in case they do not synchronize around
1666 // FindLoadedClass/DefineClass, calls, we check for parallel
1667 // loading for them, wait if a defineClass is in progress
1668 // and return the initial requestor's results
1669 // This flag does not apply to the bootstrap classloader.
1670 // With AllowParallelDefine flag==false, call through to define_instance_class
1671 // which will throw LinkageError: duplicate class definition.
1672 // False is the requested default.
1673 // For better performance, the class loaders should synchronize
1674 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1675 // potentially waste time reading and parsing the bytestream.
1676 // Note: VM callers should ensure consistency of k/class_name,class_loader
1677 // Be careful when modifying this code: once you have run
1678 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1679 // you need to find_and_remove it before returning.
1680 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1681 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1682 InstanceKlass* k, TRAPS) {
1683
1684 Symbol* name_h = k->name(); // passed in class_name may be null
1685 ClassLoaderData* loader_data = class_loader_data(class_loader);
1686 Dictionary* dictionary = loader_data->dictionary();
1687
1688 unsigned int d_hash = dictionary->compute_hash(name_h);
1689
1690 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1691 unsigned int p_hash = placeholders()->compute_hash(name_h);
1692 int p_index = placeholders()->hash_to_index(p_hash);
1693 PlaceholderEntry* probe;
1694
1695 {
1696 MutexLocker mu(SystemDictionary_lock, THREAD);
1697 // First check if class already defined
1698 if (is_parallelDefine(class_loader)) {
1699 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1700 if (check != NULL) {
1701 return check;
1702 }
1703 }
1704
1705 // Acquire define token for this class/classloader
1706 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1707 // Wait if another thread defining in parallel
1708 // All threads wait - even those that will throw duplicate class: otherwise
1709 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1710 // if other thread has not finished updating dictionary
1711 while (probe->definer() != NULL) {
1712 SystemDictionary_lock->wait();
1713 }
1714 // Only special cases allow parallel defines and can use other thread's results
1715 // Other cases fall through, and may run into duplicate defines
1716 // caught by finding an entry in the SystemDictionary
1717 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1718 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1719 SystemDictionary_lock->notify_all();
1720 #ifdef ASSERT
1721 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1722 assert(check != NULL, "definer missed recording success");
1723 #endif
1724 return probe->instance_klass();
1725 } else {
1726 // This thread will define the class (even if earlier thread tried and had an error)
1727 probe->set_definer(THREAD);
1728 }
1729 }
1730
1731 define_instance_class(k, THREAD);
1732
1733 Handle linkage_exception = Handle(); // null handle
1734
1735 // definer must notify any waiting threads
1736 {
1737 MutexLocker mu(SystemDictionary_lock, THREAD);
1738 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1739 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1740 if (probe != NULL) {
1741 if (HAS_PENDING_EXCEPTION) {
1742 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1743 CLEAR_PENDING_EXCEPTION;
1744 } else {
1745 probe->set_instance_klass(k);
1746 }
1747 probe->set_definer(NULL);
1748 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1749 SystemDictionary_lock->notify_all();
1750 }
1751 }
1752
1753 // Can't throw exception while holding lock due to rank ordering
1754 if (linkage_exception() != NULL) {
1755 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1756 }
1757
1758 return k;
1759 }
1760
1761 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1762 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1763 if (class_loader.is_null()) {
1764 return Handle(THREAD, _system_loader_lock_obj);
1765 } else {
1766 return class_loader;
1767 }
1768 }
1769
1770 // This method is added to check how often we have to wait to grab loader
1771 // lock. The results are being recorded in the performance counters defined in
1772 // ClassLoader::_sync_systemLoaderLockContentionRate and
1773 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1774 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1775 if (!UsePerfData) {
1776 return;
1777 }
1778
1779 assert(!loader_lock.is_null(), "NULL lock object");
1780
1781 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1782 == ObjectSynchronizer::owner_other) {
1783 // contention will likely happen, so increment the corresponding
1784 // contention counter.
1785 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1786 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1787 } else {
1788 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1789 }
1790 }
1791 }
1792
1793 // ----------------------------------------------------------------------------
1794 // Lookup
1795
1796 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1797 Symbol* class_name,
1798 Dictionary* dictionary) {
1799 assert_locked_or_safepoint(SystemDictionary_lock);
1800 int index = dictionary->hash_to_index(hash);
1801 return dictionary->find_class(index, hash, class_name);
1802 }
1803
1804
1805 // Basic find on classes in the midst of being loaded
1806 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1807 ClassLoaderData* loader_data) {
1808 assert_locked_or_safepoint(SystemDictionary_lock);
1809 unsigned int p_hash = placeholders()->compute_hash(class_name);
1810 int p_index = placeholders()->hash_to_index(p_hash);
1811 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1812 }
1813
1814
1815 // Used for assertions and verification only
1816 // Precalculating the hash and index is an optimization because there are many lookups
1817 // before adding the class.
1818 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1819 assert_locked_or_safepoint(SystemDictionary_lock);
1820 #ifndef ASSERT
1821 guarantee(VerifyBeforeGC ||
1822 VerifyDuringGC ||
1823 VerifyBeforeExit ||
1824 VerifyDuringStartup ||
1825 VerifyAfterGC, "too expensive");
1826 #endif
1827
1828 Dictionary* dictionary = loader_data->dictionary();
1829 unsigned int d_hash = dictionary->compute_hash(class_name);
1830 return find_class(d_hash, class_name, dictionary);
1831 }
1832
1833
1834 // ----------------------------------------------------------------------------
1835 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1836 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1837 // before a new class is used.
1838
1839 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1840 assert(k != NULL, "just checking");
1841 assert_locked_or_safepoint(Compile_lock);
1842
1843 k->set_init_state(InstanceKlass::loaded);
1844 // make sure init_state store is already done.
1845 // The compiler reads the hierarchy outside of the Compile_lock.
1846 // Access ordering is used to add to hierarchy.
1847
1848 // Link into hierachy.
1849 k->append_to_sibling_list(); // add to superklass/sibling list
1850 k->process_interfaces(THREAD); // handle all "implements" declarations
1851
1852 // Now flush all code that depended on old class hierarchy.
1853 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1854 CodeCache::flush_dependents_on(k);
1855 }
1856
1857 // ----------------------------------------------------------------------------
1858 // GC support
1859
1860 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1861 // Note: anonymous classes are not in the SD.
1862 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1863
1864 bool unloading_occurred;
1865 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1866 {
1867 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1868 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1869 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1870 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1871 if (unloading_occurred) {
1872 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
1873 JFR_ONLY(Jfr::on_unloading_classes();)
1874
1875 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
1876 ClassLoaderDataGraph::clean_module_and_package_info();
1877 constraints()->purge_loader_constraints();
1878 resolution_errors()->purge_resolution_errors();
1879 }
1880 }
1881
1882 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1883
1884 if (unloading_occurred) {
1885 SymbolTable::trigger_cleanup();
1886
1887 // Oops referenced by the protection domain cache table may get unreachable independently
1888 // of the class loader (eg. cached protection domain oops). So we need to
1889 // explicitly unlink them here.
1890 // All protection domain oops are linked to the caller class, so if nothing
1891 // unloads, this is not needed.
1892 _pd_cache_table->trigger_cleanup();
1893 }
1894
1895 return unloading_occurred;
1896 }
1897
1898 void SystemDictionary::oops_do(OopClosure* f) {
1899 f->do_oop(&_java_system_loader);
1900 f->do_oop(&_java_platform_loader);
1901 f->do_oop(&_system_loader_lock_obj);
1902 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1903
1904 // Visit extra methods
1905 invoke_method_table()->oops_do(f);
1906 }
1907
1908 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1909 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1910 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1911 it->push(well_known_klass_addr((WKID)id));
1912 }
1913 }
1914
1915 void SystemDictionary::methods_do(void f(Method*)) {
1916 // Walk methods in loaded classes
1917 MutexLocker ml(ClassLoaderDataGraph_lock);
1918 ClassLoaderDataGraph::methods_do(f);
1919 // Walk method handle intrinsics
1920 invoke_method_table()->methods_do(f);
1921 }
1922
1923 // ----------------------------------------------------------------------------
1924 // Initialization
1925
1926 void SystemDictionary::initialize(TRAPS) {
1927 // Allocate arrays
1928 _placeholders = new PlaceholderTable(_placeholder_table_size);
1929 _number_of_modifications = 0;
1930 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1931 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1932 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1933 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1934
1935 // Allocate private object used as system class loader lock
1936 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1937 // Initialize basic classes
1938 resolve_well_known_classes(CHECK);
1939 }
1940
1941 // Compact table of directions on the initialization of klasses:
1942 static const short wk_init_info[] = {
1943 #define WK_KLASS_INIT_INFO(name, symbol) \
1944 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1945
1946 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1947 #undef WK_KLASS_INIT_INFO
1948 0
1949 };
1950
1951 #ifdef ASSERT
1952 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1953 int sid;
1954 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1955 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1956 if (class_name == symbol) {
1957 return true;
1958 }
1959 }
1960 return false;
1961 }
1962 #endif
1963
1964 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1965 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1966 int sid = wk_init_info[id - FIRST_WKID];
1967 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1968 InstanceKlass** klassp = &_well_known_klasses[id];
1969
1970 if ((*klassp) == NULL) {
1971 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1972 (*klassp) = InstanceKlass::cast(k);
1973 }
1974 return ((*klassp) != NULL);
1975 }
1976
1977 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1978 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1979 for (int id = (int)start_id; id < (int)limit_id; id++) {
1980 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1981 resolve_wk_klass((WKID)id, CHECK);
1982 }
1983
1984 // move the starting value forward to the limit:
1985 start_id = limit_id;
1986 }
1987
1988 void SystemDictionary::resolve_well_known_classes(TRAPS) {
1989 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
1990
1991 // Create the ModuleEntry for java.base. This call needs to be done here,
1992 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
1993 ClassLoader::classLoader_init2(CHECK);
1994
1995 // Preload commonly used klasses
1996 WKID scan = FIRST_WKID;
1997 // first do Object, then String, Class
1998 #if INCLUDE_CDS
1999 if (UseSharedSpaces) {
2000 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2001
2002 // It's unsafe to access the archived heap regions before they
2003 // are fixed up, so we must do the fixup as early as possible
2004 // before the archived java objects are accessed by functions
2005 // such as java_lang_Class::restore_archived_mirror and
2006 // ConstantPool::restore_unshareable_info (restores the archived
2007 // resolved_references array object).
2008 //
2009 // HeapShared::fixup_mapped_heap_regions() fills the empty
2010 // spaces in the archived heap regions and may use
2011 // SystemDictionary::Object_klass(), so we can do this only after
2012 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2013 // call. No mirror objects are accessed/restored in the above call.
2014 // Mirrors are restored after java.lang.Class is loaded.
2015 HeapShared::fixup_mapped_heap_regions();
2016
2017 // Initialize the constant pool for the Object_class
2018 assert(Object_klass()->is_shared(), "must be");
2019 Object_klass()->constants()->restore_unshareable_info(CHECK);
2020 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2021 } else
2022 #endif
2023 {
2024 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2025 }
2026
2027 // Calculate offsets for String and Class classes since they are loaded and
2028 // can be used after this point.
2029 java_lang_String::compute_offsets();
2030 java_lang_Class::compute_offsets();
2031
2032 // Fixup mirrors for classes loaded before java.lang.Class.
2033 // These calls iterate over the objects currently in the perm gen
2034 // so calling them at this point is matters (not before when there
2035 // are fewer objects and not later after there are more objects
2036 // in the perm gen.
2037 Universe::initialize_basic_type_mirrors(CHECK);
2038 Universe::fixup_mirrors(CHECK);
2039
2040 // do a bunch more:
2041 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2042
2043 // Preload ref klasses and set reference types
2044 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2045 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2046
2047 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2048 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2049 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2050 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2051 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2052
2053 // JSR 292 classes
2054 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2055 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2056 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2057 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2058 WKID last = WKID_LIMIT;
2059 resolve_wk_klasses_until(last, scan, CHECK);
2060
2061 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2062 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2063 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2064 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2065 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2066 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2067 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2068 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2069 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2070 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2071
2072 { // Compute whether we should use checkPackageAccess or NOT
2073 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2074 _has_checkPackageAccess = (method != NULL);
2075 }
2076
2077 #ifdef ASSERT
2078 if (UseSharedSpaces) {
2079 assert(JvmtiExport::is_early_phase(),
2080 "All well known classes must be resolved in JVMTI early phase");
2081 for (int i = FIRST_WKID; i < last; i++) {
2082 InstanceKlass* k = _well_known_klasses[i];
2083 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2084 }
2085 }
2086 #endif
2087 }
2088
2089 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2090 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2091 BasicType SystemDictionary::box_klass_type(Klass* k) {
2092 assert(k != NULL, "");
2093 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2094 if (_box_klasses[i] == k)
2095 return (BasicType)i;
2096 }
2097 return T_OBJECT;
2098 }
2099
2100 // Constraints on class loaders. The details of the algorithm can be
2101 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2102 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2103 // that the dictionary needs to maintain a set of contraints that
2104 // must be satisfied by all classes in the dictionary.
2105 // if defining is true, then LinkageError if already in dictionary
2106 // if initiating loader, then ok if InstanceKlass matches existing entry
2107
2108 void SystemDictionary::check_constraints(unsigned int d_hash,
2109 InstanceKlass* k,
2110 Handle class_loader,
2111 bool defining,
2112 TRAPS) {
2113 ResourceMark rm(THREAD);
2114 stringStream ss;
2115 bool throwException = false;
2116
2117 {
2118 Symbol *name = k->name();
2119 ClassLoaderData *loader_data = class_loader_data(class_loader);
2120
2121 MutexLocker mu(SystemDictionary_lock, THREAD);
2122
2123 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2124 if (check != NULL) {
2125 // If different InstanceKlass - duplicate class definition,
2126 // else - ok, class loaded by a different thread in parallel.
2127 // We should only have found it if it was done loading and ok to use.
2128 // The dictionary only holds instance classes, placeholders
2129 // also hold array classes.
2130
2131 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2132 if ((defining == true) || (k != check)) {
2133 throwException = true;
2134 ss.print("loader %s", loader_data->loader_name_and_id());
2135 ss.print(" attempted duplicate %s definition for %s. (%s)",
2136 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2137 } else {
2138 return;
2139 }
2140 }
2141
2142 #ifdef ASSERT
2143 Symbol* ph_check = find_placeholder(name, loader_data);
2144 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2145 #endif
2146
2147 if (throwException == false) {
2148 if (constraints()->check_or_update(k, class_loader, name) == false) {
2149 throwException = true;
2150 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2151 ss.print(" wants to load %s %s.",
2152 k->external_kind(), k->external_name());
2153 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2154 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2155 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2156 existing_klass->external_kind(),
2157 existing_klass->class_loader_data()->loader_name_and_id(),
2158 existing_klass->class_in_module_of_loader(false, true));
2159 } else {
2160 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2161 }
2162 }
2163 }
2164 }
2165
2166 // Throw error now if needed (cannot throw while holding
2167 // SystemDictionary_lock because of rank ordering)
2168 if (throwException == true) {
2169 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2170 }
2171 }
2172
2173 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2174 // have been called.
2175 void SystemDictionary::update_dictionary(unsigned int d_hash,
2176 int p_index, unsigned int p_hash,
2177 InstanceKlass* k,
2178 Handle class_loader,
2179 TRAPS) {
2180 // Compile_lock prevents systemDictionary updates during compilations
2181 assert_locked_or_safepoint(Compile_lock);
2182 Symbol* name = k->name();
2183 ClassLoaderData *loader_data = class_loader_data(class_loader);
2184
2185 {
2186 MutexLocker mu1(SystemDictionary_lock, THREAD);
2187
2188 // See whether biased locking is enabled and if so set it for this
2189 // klass.
2190 // Note that this must be done past the last potential blocking
2191 // point / safepoint. We enable biased locking lazily using a
2192 // VM_Operation to iterate the SystemDictionary and installing the
2193 // biasable mark word into each InstanceKlass's prototype header.
2194 // To avoid race conditions where we accidentally miss enabling the
2195 // optimization for one class in the process of being added to the
2196 // dictionary, we must not safepoint after the test of
2197 // BiasedLocking::enabled().
2198 if (UseBiasedLocking && BiasedLocking::enabled()) {
2199 // Set biased locking bit for all loaded classes; it will be
2200 // cleared if revocation occurs too often for this type
2201 // NOTE that we must only do this when the class is initally
2202 // defined, not each time it is referenced from a new class loader
2203 if (oopDesc::equals(k->class_loader(), class_loader()) && !k->is_value()) {
2204 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2205 }
2206 }
2207
2208 // Make a new dictionary entry.
2209 Dictionary* dictionary = loader_data->dictionary();
2210 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2211 if (sd_check == NULL) {
2212 dictionary->add_klass(d_hash, name, k);
2213
2214 notice_modification();
2215 }
2216 #ifdef ASSERT
2217 sd_check = find_class(d_hash, name, dictionary);
2218 assert (sd_check != NULL, "should have entry in dictionary");
2219 // Note: there may be a placeholder entry: for circularity testing
2220 // or for parallel defines
2221 #endif
2222 SystemDictionary_lock->notify_all();
2223 }
2224 }
2225
2226
2227 // Try to find a class name using the loader constraints. The
2228 // loader constraints might know about a class that isn't fully loaded
2229 // yet and these will be ignored.
2230 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2231 Symbol* class_name, Handle class_loader, TRAPS) {
2232
2233 // First see if it has been loaded directly.
2234 // Force the protection domain to be null. (This removes protection checks.)
2235 Handle no_protection_domain;
2236 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2237 no_protection_domain, CHECK_NULL);
2238 if (klass != NULL)
2239 return klass;
2240
2241 // Now look to see if it has been loaded elsewhere, and is subject to
2242 // a loader constraint that would require this loader to return the
2243 // klass that is already loaded.
2244 if (FieldType::is_array(class_name)) {
2245 // For array classes, their Klass*s are not kept in the
2246 // constraint table. The element Klass*s are.
2247 FieldArrayInfo fd;
2248 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2249 if (t != T_OBJECT && t != T_VALUETYPE) {
2250 klass = Universe::typeArrayKlassObj(t);
2251 } else {
2252 MutexLocker mu(SystemDictionary_lock, THREAD);
2253 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2254 }
2255 // If element class already loaded, allocate array klass
2256 if (klass != NULL) {
2257 klass = klass->array_klass_or_null(fd.storage_props(), fd.dimension());
2258 }
2259 } else {
2260 MutexLocker mu(SystemDictionary_lock, THREAD);
2261 // Non-array classes are easy: simply check the constraint table.
2262 klass = constraints()->find_constrained_klass(class_name, class_loader);
2263 }
2264
2265 return klass;
2266 }
2267
2268
2269 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2270 Handle class_loader1,
2271 Handle class_loader2,
2272 Thread* THREAD) {
2273 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2274 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2275
2276 Symbol* constraint_name = NULL;
2277 // Needs to be in same scope as constraint_name in case a Symbol is created and
2278 // assigned to constraint_name.
2279 FieldArrayInfo fd;
2280 if (!FieldType::is_array(class_name)) {
2281 constraint_name = class_name;
2282 } else {
2283 // For array classes, their Klass*s are not kept in the
2284 // constraint table. The element classes are.
2285 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2286 // primitive types always pass
2287 if (t != T_OBJECT) {
2288 return true;
2289 } else {
2290 constraint_name = fd.object_key();
2291 }
2292 }
2293
2294 Dictionary* dictionary1 = loader_data1->dictionary();
2295 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2296
2297 Dictionary* dictionary2 = loader_data2->dictionary();
2298 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2299
2300 {
2301 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2302 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2303 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2304 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2305 klass2, class_loader2);
2306 }
2307 }
2308
2309 // Add entry to resolution error table to record the error when the first
2310 // attempt to resolve a reference to a class has failed.
2311 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2312 Symbol* error, Symbol* message) {
2313 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2314 int index = resolution_errors()->hash_to_index(hash);
2315 {
2316 MutexLocker ml(SystemDictionary_lock, Thread::current());
2317 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2318 }
2319 }
2320
2321 // Delete a resolution error for RedefineClasses for a constant pool is going away
2322 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2323 resolution_errors()->delete_entry(pool);
2324 }
2325
2326 // Lookup resolution error table. Returns error if found, otherwise NULL.
2327 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2328 Symbol** message) {
2329 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2330 int index = resolution_errors()->hash_to_index(hash);
2331 {
2332 MutexLocker ml(SystemDictionary_lock, Thread::current());
2333 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2334 if (entry != NULL) {
2335 *message = entry->message();
2336 return entry->error();
2337 } else {
2338 return NULL;
2339 }
2340 }
2341 }
2342
2343
2344 // Signature constraints ensure that callers and callees agree about
2345 // the meaning of type names in their signatures. This routine is the
2346 // intake for constraints. It collects them from several places:
2347 //
2348 // * LinkResolver::resolve_method (if check_access is true) requires
2349 // that the resolving class (the caller) and the defining class of
2350 // the resolved method (the callee) agree on each type in the
2351 // method's signature.
2352 //
2353 // * LinkResolver::resolve_interface_method performs exactly the same
2354 // checks.
2355 //
2356 // * LinkResolver::resolve_field requires that the constant pool
2357 // attempting to link to a field agree with the field's defining
2358 // class about the type of the field signature.
2359 //
2360 // * klassVtable::initialize_vtable requires that, when a class
2361 // overrides a vtable entry allocated by a superclass, that the
2362 // overriding method (i.e., the callee) agree with the superclass
2363 // on each type in the method's signature.
2364 //
2365 // * klassItable::initialize_itable requires that, when a class fills
2366 // in its itables, for each non-abstract method installed in an
2367 // itable, the method (i.e., the callee) agree with the interface
2368 // on each type in the method's signature.
2369 //
2370 // All those methods have a boolean (check_access, checkconstraints)
2371 // which turns off the checks. This is used from specialized contexts
2372 // such as bootstrapping, dumping, and debugging.
2373 //
2374 // No direct constraint is placed between the class and its
2375 // supertypes. Constraints are only placed along linked relations
2376 // between callers and callees. When a method overrides or implements
2377 // an abstract method in a supertype (superclass or interface), the
2378 // constraints are placed as if the supertype were the caller to the
2379 // overriding method. (This works well, since callers to the
2380 // supertype have already established agreement between themselves and
2381 // the supertype.) As a result of all this, a class can disagree with
2382 // its supertype about the meaning of a type name, as long as that
2383 // class neither calls a relevant method of the supertype, nor is
2384 // called (perhaps via an override) from the supertype.
2385 //
2386 //
2387 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2388 //
2389 // Make sure all class components (including arrays) in the given
2390 // signature will be resolved to the same class in both loaders.
2391 // Returns the name of the type that failed a loader constraint check, or
2392 // NULL if no constraint failed. No exception except OOME is thrown.
2393 // Arrays are not added to the loader constraint table, their elements are.
2394 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2395 Handle loader1, Handle loader2,
2396 bool is_method, TRAPS) {
2397 // Nothing to do if loaders are the same.
2398 if (oopDesc::equals(loader1(), loader2())) {
2399 return NULL;
2400 }
2401
2402 SignatureStream sig_strm(signature, is_method);
2403 while (!sig_strm.is_done()) {
2404 if (sig_strm.is_object()) {
2405 Symbol* sig = sig_strm.as_symbol();
2406 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2407 return sig;
2408 }
2409 }
2410 sig_strm.next();
2411 }
2412 return NULL;
2413 }
2414
2415
2416 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2417 Symbol* signature,
2418 TRAPS) {
2419 methodHandle empty;
2420 assert(MethodHandles::is_signature_polymorphic(iid) &&
2421 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2422 iid != vmIntrinsics::_invokeGeneric,
2423 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2424
2425 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2426 int index = invoke_method_table()->hash_to_index(hash);
2427 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2428 methodHandle m;
2429 if (spe == NULL || spe->method() == NULL) {
2430 spe = NULL;
2431 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2432 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2433 if (!Arguments::is_interpreter_only()) {
2434 // Generate a compiled form of the MH intrinsic.
2435 AdapterHandlerLibrary::create_native_wrapper(m);
2436 // Check if have the compiled code.
2437 if (!m->has_compiled_code()) {
2438 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2439 "Out of space in CodeCache for method handle intrinsic", empty);
2440 }
2441 }
2442 // Now grab the lock. We might have to throw away the new method,
2443 // if a racing thread has managed to install one at the same time.
2444 {
2445 MutexLocker ml(SystemDictionary_lock, THREAD);
2446 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2447 if (spe == NULL)
2448 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2449 if (spe->method() == NULL)
2450 spe->set_method(m());
2451 }
2452 }
2453
2454 assert(spe != NULL && spe->method() != NULL, "");
2455 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2456 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2457 "MH intrinsic invariant");
2458 return spe->method();
2459 }
2460
2461 // Helper for unpacking the return value from linkMethod and linkCallSite.
2462 static methodHandle unpack_method_and_appendix(Handle mname,
2463 Klass* accessing_klass,
2464 objArrayHandle appendix_box,
2465 Handle* appendix_result,
2466 TRAPS) {
2467 methodHandle empty;
2468 if (mname.not_null()) {
2469 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2470 if (m != NULL) {
2471 oop appendix = appendix_box->obj_at(0);
2472 if (TraceMethodHandles) {
2473 #ifndef PRODUCT
2474 ttyLocker ttyl;
2475 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2476 m->print();
2477 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2478 tty->cr();
2479 #endif //PRODUCT
2480 }
2481 (*appendix_result) = Handle(THREAD, appendix);
2482 // the target is stored in the cpCache and if a reference to this
2483 // MemberName is dropped we need a way to make sure the
2484 // class_loader containing this method is kept alive.
2485 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2486 this_key->record_dependency(m->method_holder());
2487 return methodHandle(THREAD, m);
2488 }
2489 }
2490 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2491 return empty;
2492 }
2493
2494 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2495 Symbol* name,
2496 Symbol* signature,
2497 Klass* accessing_klass,
2498 Handle *appendix_result,
2499 TRAPS) {
2500 methodHandle empty;
2501 assert(THREAD->can_call_java() ,"");
2502 Handle method_type =
2503 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2504
2505 int ref_kind = JVM_REF_invokeVirtual;
2506 oop name_oop = StringTable::intern(name, CHECK_(empty));
2507 Handle name_str (THREAD, name_oop);
2508 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2509 assert(appendix_box->obj_at(0) == NULL, "");
2510
2511 // This should not happen. JDK code should take care of that.
2512 if (accessing_klass == NULL || method_type.is_null()) {
2513 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2514 }
2515
2516 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2517 JavaCallArguments args;
2518 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2519 args.push_int(ref_kind);
2520 args.push_oop(Handle(THREAD, klass->java_mirror()));
2521 args.push_oop(name_str);
2522 args.push_oop(method_type);
2523 args.push_oop(appendix_box);
2524 JavaValue result(T_OBJECT);
2525 JavaCalls::call_static(&result,
2526 SystemDictionary::MethodHandleNatives_klass(),
2527 vmSymbols::linkMethod_name(),
2528 vmSymbols::linkMethod_signature(),
2529 &args, CHECK_(empty));
2530 Handle mname(THREAD, (oop) result.get_jobject());
2531 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2532 }
2533
2534 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2535 // We must ensure that all class loaders everywhere will reach this class, for any client.
2536 // This is a safe bet for public classes in java.lang, such as Object and String.
2537 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2538 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2539 static bool is_always_visible_class(oop mirror) {
2540 Klass* klass = java_lang_Class::as_Klass(mirror);
2541 if (klass->is_objArray_klass()) {
2542 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2543 }
2544 if (klass->is_typeArray_klass()) {
2545 return true; // primitive array
2546 }
2547 assert(klass->is_instance_klass(), "%s", klass->external_name());
2548 return klass->is_public() &&
2549 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2550 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2551 }
2552
2553
2554 // Return the Java mirror (java.lang.Class instance) for a single-character
2555 // descriptor. This result, when available, is the same as produced by the
2556 // heavier API point of the same name that takes a Symbol.
2557 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2558 return java_lang_Class::primitive_mirror(char2type(signature_char));
2559 }
2560
2561 // Find or construct the Java mirror (java.lang.Class instance) for a
2562 // for the given field type signature, as interpreted relative to the
2563 // given class loader. Handles primitives, void, references, arrays,
2564 // and all other reflectable types, except method types.
2565 // N.B. Code in reflection should use this entry point.
2566 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2567 Klass* accessing_klass,
2568 Handle class_loader,
2569 Handle protection_domain,
2570 SignatureStream::FailureMode failure_mode,
2571 TRAPS) {
2572 Handle empty;
2573
2574 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2575 "one or the other, or perhaps neither");
2576
2577 Symbol* type = signature;
2578
2579 // What we have here must be a valid field descriptor,
2580 // and all valid field descriptors are supported.
2581 // Produce the same java.lang.Class that reflection reports.
2582 if (type->utf8_length() == 1) {
2583
2584 // It's a primitive. (Void has a primitive mirror too.)
2585 char ch = type->char_at(0);
2586 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2587 return Handle(THREAD, find_java_mirror_for_type(ch));
2588
2589 } else if (FieldType::is_obj(type) || FieldType::is_valuetype(type) || FieldType::is_array(type)) {
2590
2591 // It's a reference type.
2592 if (accessing_klass != NULL) {
2593 class_loader = Handle(THREAD, accessing_klass->class_loader());
2594 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2595 }
2596 Klass* constant_type_klass;
2597 if (failure_mode == SignatureStream::ReturnNull) {
2598 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2599 CHECK_(empty));
2600 } else {
2601 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2602 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2603 throw_error, CHECK_(empty));
2604 }
2605 if (constant_type_klass == NULL) {
2606 return Handle(); // report failure this way
2607 }
2608 Handle mirror(THREAD, constant_type_klass->java_mirror());
2609
2610 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2611 if (accessing_klass != NULL) {
2612 Klass* sel_klass = constant_type_klass;
2613 bool fold_type_to_class = true;
2614 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2615 fold_type_to_class, CHECK_(empty));
2616 }
2617
2618 return mirror;
2619
2620 }
2621
2622 // Fall through to an error.
2623 assert(false, "unsupported mirror syntax");
2624 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2625 }
2626
2627
2628 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2629 // signature, as interpreted relative to the given class loader.
2630 // Because of class loader constraints, all method handle usage must be
2631 // consistent with this loader.
2632 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2633 Klass* accessing_klass,
2634 TRAPS) {
2635 Handle empty;
2636 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2637 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2638 int index = invoke_method_table()->hash_to_index(hash);
2639 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2640 if (spe != NULL && spe->method_type() != NULL) {
2641 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2642 return Handle(THREAD, spe->method_type());
2643 } else if (!THREAD->can_call_java()) {
2644 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2645 return Handle(); // do not attempt from within compiler, unless it was cached
2646 }
2647
2648 Handle class_loader, protection_domain;
2649 if (accessing_klass != NULL) {
2650 class_loader = Handle(THREAD, accessing_klass->class_loader());
2651 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2652 }
2653 bool can_be_cached = true;
2654 int npts = ArgumentCount(signature).size();
2655 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2656 int arg = 0;
2657 Handle rt; // the return type from the signature
2658 ResourceMark rm(THREAD);
2659 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2660 oop mirror = NULL;
2661 if (can_be_cached) {
2662 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2663 mirror = ss.as_java_mirror(Handle(), Handle(),
2664 SignatureStream::ReturnNull, CHECK_(empty));
2665 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2666 // Fall back to accessing_klass context.
2667 can_be_cached = false;
2668 }
2669 }
2670 if (!can_be_cached) {
2671 // Resolve, throwing a real error if it doesn't work.
2672 mirror = ss.as_java_mirror(class_loader, protection_domain,
2673 SignatureStream::NCDFError, CHECK_(empty));
2674 }
2675 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2676 if (ss.at_return_type())
2677 rt = Handle(THREAD, mirror);
2678 else
2679 pts->obj_at_put(arg++, mirror);
2680
2681 // Check accessibility.
2682 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2683 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2684 mirror = NULL; // safety
2685 // Emulate ConstantPool::verify_constant_pool_resolve.
2686 bool fold_type_to_class = true;
2687 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2688 fold_type_to_class, CHECK_(empty));
2689 }
2690 }
2691 assert(arg == npts, "");
2692
2693 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2694 JavaCallArguments args(Handle(THREAD, rt()));
2695 args.push_oop(pts);
2696 JavaValue result(T_OBJECT);
2697 JavaCalls::call_static(&result,
2698 SystemDictionary::MethodHandleNatives_klass(),
2699 vmSymbols::findMethodHandleType_name(),
2700 vmSymbols::findMethodHandleType_signature(),
2701 &args, CHECK_(empty));
2702 Handle method_type(THREAD, (oop) result.get_jobject());
2703
2704 if (can_be_cached) {
2705 // We can cache this MethodType inside the JVM.
2706 MutexLocker ml(SystemDictionary_lock, THREAD);
2707 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2708 if (spe == NULL)
2709 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2710 if (spe->method_type() == NULL) {
2711 spe->set_method_type(method_type());
2712 }
2713 }
2714
2715 // report back to the caller with the MethodType
2716 return method_type;
2717 }
2718
2719 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2720 Klass* accessing_klass,
2721 TRAPS) {
2722 Handle empty;
2723 ResourceMark rm(THREAD);
2724 SignatureStream ss(signature, /*is_method=*/ false);
2725 if (!ss.is_done()) {
2726 Handle class_loader, protection_domain;
2727 if (accessing_klass != NULL) {
2728 class_loader = Handle(THREAD, accessing_klass->class_loader());
2729 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2730 }
2731 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2732 ss.next();
2733 if (ss.is_done()) {
2734 return Handle(THREAD, mirror);
2735 }
2736 }
2737 return empty;
2738 }
2739
2740 // Ask Java code to find or construct a method handle constant.
2741 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2742 int ref_kind, //e.g., JVM_REF_invokeVirtual
2743 Klass* callee,
2744 Symbol* name,
2745 Symbol* signature,
2746 TRAPS) {
2747 Handle empty;
2748 if (caller == NULL) {
2749 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2750 }
2751 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2752 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2753
2754 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2755 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2756 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2757 java_lang_invoke_MemberName::set_name (mname(), name_str());
2758 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2759 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2760
2761 if (ref_kind == JVM_REF_invokeVirtual &&
2762 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2763 // Skip resolution for public signature polymorphic methods such as
2764 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2765 // They require appendix argument which MemberName resolution doesn't handle.
2766 // There's special logic on JDK side to handle them
2767 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2768 } else {
2769 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2770 }
2771
2772 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2773 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2774
2775 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2776 JavaCallArguments args;
2777 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2778 args.push_int(ref_kind);
2779 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2780 args.push_oop(name_str);
2781 args.push_oop(type);
2782 JavaValue result(T_OBJECT);
2783 JavaCalls::call_static(&result,
2784 SystemDictionary::MethodHandleNatives_klass(),
2785 vmSymbols::linkMethodHandleConstant_name(),
2786 vmSymbols::linkMethodHandleConstant_signature(),
2787 &args, CHECK_(empty));
2788 return Handle(THREAD, (oop) result.get_jobject());
2789 }
2790
2791 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2792 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2793 // with linkage results being stored back into the bootstrap specifier.
2794 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2795 // Resolve the bootstrap specifier, its name, type, and static arguments
2796 bootstrap_specifier.resolve_bsm(CHECK);
2797
2798 // This should not happen. JDK code should take care of that.
2799 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2800 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2801 }
2802
2803 bool is_indy = bootstrap_specifier.is_method_call();
2804 objArrayHandle appendix_box;
2805 if (is_indy) {
2806 // Some method calls may require an appendix argument. Arrange to receive it.
2807 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2808 assert(appendix_box->obj_at(0) == NULL, "");
2809 }
2810
2811 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2812 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2813 JavaCallArguments args;
2814 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2815 args.push_int(bootstrap_specifier.bss_index());
2816 args.push_oop(bootstrap_specifier.bsm());
2817 args.push_oop(bootstrap_specifier.name_arg());
2818 args.push_oop(bootstrap_specifier.type_arg());
2819 args.push_oop(bootstrap_specifier.arg_values());
2820 if (is_indy) {
2821 args.push_oop(appendix_box);
2822 }
2823 JavaValue result(T_OBJECT);
2824 JavaCalls::call_static(&result,
2825 SystemDictionary::MethodHandleNatives_klass(),
2826 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2827 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2828 &args, CHECK);
2829
2830 Handle value(THREAD, (oop) result.get_jobject());
2831 if (is_indy) {
2832 Handle appendix;
2833 methodHandle method = unpack_method_and_appendix(value,
2834 bootstrap_specifier.caller(),
2835 appendix_box,
2836 &appendix, CHECK);
2837 bootstrap_specifier.set_resolved_method(method, appendix);
2838 } else {
2839 bootstrap_specifier.set_resolved_value(value);
2840 }
2841
2842 // sanity check
2843 assert(bootstrap_specifier.is_resolved() ||
2844 (bootstrap_specifier.is_method_call() &&
2845 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2846 }
2847
2848 // Protection domain cache table handling
2849
2850 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2851 return _pd_cache_table->get(protection_domain);
2852 }
2853
2854 // ----------------------------------------------------------------------------
2855
2856 void SystemDictionary::print_on(outputStream *st) {
2857 CDS_ONLY(SystemDictionaryShared::print_on(st));
2858 GCMutexLocker mu(SystemDictionary_lock);
2859
2860 ClassLoaderDataGraph::print_dictionary(st);
2861
2862 // Placeholders
2863 placeholders()->print_on(st);
2864 st->cr();
2865
2866 // loader constraints - print under SD_lock
2867 constraints()->print_on(st);
2868 st->cr();
2869
2870 _pd_cache_table->print_on(st);
2871 st->cr();
2872 }
2873
2874 void SystemDictionary::print() { print_on(tty); }
2875
2876 void SystemDictionary::verify() {
2877 guarantee(constraints() != NULL,
2878 "Verify of loader constraints failed");
2879 guarantee(placeholders()->number_of_entries() >= 0,
2880 "Verify of placeholders failed");
2881
2882 GCMutexLocker mu(SystemDictionary_lock);
2883
2884 // Verify dictionary
2885 ClassLoaderDataGraph::verify_dictionary();
2886
2887 placeholders()->verify();
2888
2889 // Verify constraint table
2890 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2891 constraints()->verify(placeholders());
2892
2893 _pd_cache_table->verify();
2894 }
2895
2896 void SystemDictionary::dump(outputStream *st, bool verbose) {
2897 assert_locked_or_safepoint(SystemDictionary_lock);
2898 if (verbose) {
2899 print_on(st);
2900 } else {
2901 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2902 ClassLoaderDataGraph::print_table_statistics(st);
2903 placeholders()->print_table_statistics(st, "Placeholder Table");
2904 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2905 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
2906 }
2907 }
2908
2909 TableStatistics SystemDictionary::placeholders_statistics() {
2910 MutexLocker ml(SystemDictionary_lock);
2911 return placeholders()->statistics_calculate();
2912 }
2913
2914 TableStatistics SystemDictionary::loader_constraints_statistics() {
2915 MutexLocker ml(SystemDictionary_lock);
2916 return constraints()->statistics_calculate();
2917 }
2918
2919 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
2920 MutexLocker ml(SystemDictionary_lock);
2921 return pd_cache_table()->statistics_calculate();
2922 }
2923
2924 // Utility for dumping dictionaries.
2925 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2926 DCmdWithParser(output, heap),
2927 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2928 "BOOLEAN", false, "false") {
2929 _dcmdparser.add_dcmd_option(&_verbose);
2930 }
2931
2932 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2933 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2934 _verbose.value());
2935 VMThread::execute(&dumper);
2936 }
2937
2938 int SystemDictionaryDCmd::num_arguments() {
2939 ResourceMark rm;
2940 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2941 if (dcmd != NULL) {
2942 DCmdMark mark(dcmd);
2943 return dcmd->_dcmdparser.num_arguments();
2944 } else {
2945 return 0;
2946 }
2947 }
2948
2949 void SystemDictionary::initialize_oop_storage() {
2950 _vm_weak_oop_storage =
2951 new OopStorage("VM Weak Oop Handles",
2952 VMWeakAlloc_lock,
2953 VMWeakActive_lock);
2954 }
2955
2956 OopStorage* SystemDictionary::vm_weak_oop_storage() {
2957 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
2958 return _vm_weak_oop_storage;
2959 }