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/systemDictionary.hpp"
44 #include "classfile/vmSymbols.hpp"
45 #include "code/codeCache.hpp"
46 #include "compiler/compileBroker.hpp"
47 #include "gc/shared/gcTraceTime.inline.hpp"
48 #include "gc/shared/oopStorage.inline.hpp"
49 #include "interpreter/bytecodeStream.hpp"
50 #include "interpreter/interpreter.hpp"
51 #include "jfr/jfrEvents.hpp"
52 #include "logging/log.hpp"
53 #include "logging/logStream.hpp"
54 #include "memory/filemap.hpp"
55 #include "memory/heapShared.hpp"
56 #include "memory/metaspaceClosure.hpp"
57 #include "memory/oopFactory.hpp"
58 #include "memory/resourceArea.hpp"
59 #include "oops/access.inline.hpp"
60 #include "oops/instanceKlass.hpp"
61 #include "oops/instanceRefKlass.hpp"
62 #include "oops/klass.inline.hpp"
63 #include "oops/method.inline.hpp"
64 #include "oops/methodData.hpp"
65 #include "oops/objArrayKlass.hpp"
66 #include "oops/objArrayOop.inline.hpp"
67 #include "oops/oop.inline.hpp"
68 #include "oops/symbol.hpp"
69 #include "oops/typeArrayKlass.hpp"
70 #include "oops/valueKlass.hpp"
71 #include "prims/jvmtiExport.hpp"
72 #include "prims/resolvedMethodTable.hpp"
73 #include "prims/methodHandles.hpp"
74 #include "runtime/arguments.hpp"
75 #include "runtime/biasedLocking.hpp"
76 #include "runtime/fieldType.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/orderAccess.hpp"
82 #include "runtime/os.hpp"
83 #include "runtime/sharedRuntime.hpp"
84 #include "runtime/signature.hpp"
85 #include "services/classLoadingService.hpp"
86 #include "services/diagnosticCommand.hpp"
87 #include "services/threadService.hpp"
88 #include "utilities/macros.hpp"
89 #if INCLUDE_CDS
90 #include "classfile/systemDictionaryShared.hpp"
91 #endif
92 #if INCLUDE_JVMCI
93 #include "jvmci/jvmciRuntime.hpp"
94 #endif
95 #if INCLUDE_JFR
96 #include "jfr/jfr.hpp"
97 #endif
98
99 PlaceholderTable* SystemDictionary::_placeholders = NULL;
100 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
101 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
102 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
103 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
104
105 int SystemDictionary::_number_of_modifications = 0;
106 oop SystemDictionary::_system_loader_lock_obj = NULL;
107
108 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
109 = { NULL /*, NULL...*/ };
110
111 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
112
113 oop SystemDictionary::_java_system_loader = NULL;
114 oop SystemDictionary::_java_platform_loader = NULL;
115
116 bool SystemDictionary::_has_checkPackageAccess = false;
117
118 // Default ProtectionDomainCacheSize value
119
120 const int defaultProtectionDomainCacheSize = 1009;
121
122 OopStorage* SystemDictionary::_vm_weak_oop_storage = NULL;
123
124
125 // ----------------------------------------------------------------------------
126 // Java-level SystemLoader and PlatformLoader
127
128 oop SystemDictionary::java_system_loader() {
129 return _java_system_loader;
130 }
131
132 oop SystemDictionary::java_platform_loader() {
133 return _java_platform_loader;
134 }
135
136 void SystemDictionary::compute_java_loaders(TRAPS) {
137 JavaValue result(T_OBJECT);
138 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
139 JavaCalls::call_static(&result,
140 class_loader_klass,
141 vmSymbols::getSystemClassLoader_name(),
142 vmSymbols::void_classloader_signature(),
143 CHECK);
144
145 _java_system_loader = (oop)result.get_jobject();
146
147 JavaCalls::call_static(&result,
148 class_loader_klass,
149 vmSymbols::getPlatformClassLoader_name(),
150 vmSymbols::void_classloader_signature(),
151 CHECK);
152
153 _java_platform_loader = (oop)result.get_jobject();
154 }
155
156 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader) {
157 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
158 return ClassLoaderDataGraph::find_or_create(class_loader);
159 }
160
161 // ----------------------------------------------------------------------------
162 // Parallel class loading check
163
164 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
165 if (class_loader.is_null()) return true;
166 if (AlwaysLockClassLoader) return false;
167 return java_lang_ClassLoader::parallelCapable(class_loader());
168 }
169 // ----------------------------------------------------------------------------
170 // ParallelDefineClass flag does not apply to bootclass loader
171 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
172 if (class_loader.is_null()) return false;
173 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
174 return true;
175 }
176 return false;
177 }
178
179 // Returns true if the passed class loader is the builtin application class loader
180 // or a custom system class loader. A customer system class loader can be
181 // specified via -Djava.system.class.loader.
182 bool SystemDictionary::is_system_class_loader(oop class_loader) {
183 if (class_loader == NULL) {
184 return false;
185 }
186 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
187 oopDesc::equals(class_loader, _java_system_loader));
188 }
189
190 // Returns true if the passed class loader is the platform class loader.
191 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
192 if (class_loader == NULL) {
193 return false;
194 }
195 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
196 }
197
198 // ----------------------------------------------------------------------------
199 // Resolving of classes
200
201 // Forwards to resolve_or_null
202
203 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
204 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
205 if (HAS_PENDING_EXCEPTION || klass == NULL) {
206 // can return a null klass
207 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
208 }
209 return klass;
210 }
211
212 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
213 bool throw_error,
214 Klass* klass, TRAPS) {
215 if (HAS_PENDING_EXCEPTION) {
216 // If we have a pending exception we forward it to the caller, unless throw_error is true,
217 // in which case we have to check whether the pending exception is a ClassNotFoundException,
218 // and if so convert it to a NoClassDefFoundError
219 // And chain the original ClassNotFoundException
220 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
221 ResourceMark rm(THREAD);
222 assert(klass == NULL, "Should not have result with exception pending");
223 Handle e(THREAD, PENDING_EXCEPTION);
224 CLEAR_PENDING_EXCEPTION;
225 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
226 } else {
227 return NULL;
228 }
229 }
230 // Class not found, throw appropriate error or exception depending on value of throw_error
231 if (klass == NULL) {
232 ResourceMark rm(THREAD);
233 if (throw_error) {
234 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
235 } else {
236 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
237 }
238 }
239 return klass;
240 }
241
242
243 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
244 bool throw_error, TRAPS)
245 {
246 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
247 }
248
249
250 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
251
252 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
253 if (FieldType::is_array(class_name)) {
254 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
255 } else {
256 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
257 }
258 }
259
260 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
261 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
262 Handle class_loader,
263 Handle protection_domain,
264 TRAPS) {
265 assert(class_name != NULL && !FieldType::is_array(class_name), "must be");
266 if (FieldType::is_obj(class_name) || FieldType::is_valuetype(class_name)) {
267 ResourceMark rm(THREAD);
268 // Ignore wrapping L and ;. (and Q and ; for value types);
269 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
270 class_name->utf8_length() - 2, CHECK_NULL);
271 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
272 } else {
273 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
274 }
275 }
276
277 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
278 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
279 }
280
281 // Forwards to resolve_instance_class_or_null
282
283 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
284 Handle class_loader,
285 Handle protection_domain,
286 TRAPS) {
287 assert(FieldType::is_array(class_name), "must be array");
288 Klass* k = NULL;
289 FieldArrayInfo fd;
290 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
291 // of this call
292 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
293 if (t == T_OBJECT || t == T_VALUETYPE) {
294 // naked oop "k" is OK here -- we assign back into it
295 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
296 class_loader,
297 protection_domain,
298 CHECK_NULL);
299 if (k != NULL) {
300 k = k->array_klass(fd.dimension(), CHECK_NULL);
301 }
302 } else {
303 k = Universe::typeArrayKlassObj(t);
304 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
305 }
306 return k;
307 }
308
309 // Must be called for any super-class or super-interface resolution
310 // during class definition to allow class circularity checking
311 // super-interface callers:
312 // parse_interfaces - for defineClass & jvmtiRedefineClasses
313 // super-class callers:
314 // ClassFileParser - for defineClass & jvmtiRedefineClasses
315 // load_shared_class - while loading a class from shared archive
316 // resolve_instance_class_or_null:
317 // via: handle_parallel_super_load
318 // when resolving a class that has an existing placeholder with
319 // a saved superclass [i.e. a defineClass is currently in progress]
320 // if another thread is trying to resolve the class, it must do
321 // super-class checks on its own thread to catch class circularity
322 // This last call is critical in class circularity checking for cases
323 // where classloading is delegated to different threads and the
324 // classloader lock is released.
325 // Take the case: Base->Super->Base
326 // 1. If thread T1 tries to do a defineClass of class Base
327 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
328 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
329 // so it tries to load Super
330 // 3. If we load the class internally, or user classloader uses same thread
331 // loadClassFromxxx or defineClass via parseClassFile Super ...
332 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
333 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
334 // 3.4 calls resolve_super_or_fail Base
335 // 3.5 finds T1,Base -> throws class circularity
336 //OR 4. If T2 tries to resolve Super via defineClass Super ...
337 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
338 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
339 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
340 // 4.4 finds T2, Super -> throws class circularity
341 // Must be called, even if superclass is null, since this is
342 // where the placeholder entry is created which claims this
343 // thread is loading this class/classloader.
344 // Be careful when modifying this code: once you have run
345 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
346 // you need to find_and_remove it before returning.
347 // So be careful to not exit with a CHECK_ macro betweeen these calls.
348 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
349 Symbol* super_name,
350 Handle class_loader,
351 Handle protection_domain,
352 bool is_superclass,
353 TRAPS) {
354 assert(!FieldType::is_array(super_name), "invalid super class name");
355 #if INCLUDE_CDS
356 if (DumpSharedSpaces) {
357 // Special processing for handling UNREGISTERED shared classes.
358 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
359 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
360 if (k) {
361 return k;
362 }
363 }
364 #endif // INCLUDE_CDS
365
366 // Double-check, if child class is already loaded, just return super-class,interface
367 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
368 // dictionary.
369 // Make sure there's a placeholder for the *child* before resolving.
370 // Used as a claim that this thread is currently loading superclass/classloader
371 // Used here for ClassCircularity checks and also for heap verification
372 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
373 // Must check ClassCircularity before checking if super class is already loaded.
374 //
375 // We might not already have a placeholder if this child_name was
376 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
377 // the name of the class might not be known until the stream is actually
378 // parsed.
379 // Bugs 4643874, 4715493
380
381 ClassLoaderData* loader_data = class_loader_data(class_loader);
382 Dictionary* dictionary = loader_data->dictionary();
383 unsigned int d_hash = dictionary->compute_hash(child_name);
384 unsigned int p_hash = placeholders()->compute_hash(child_name);
385 int p_index = placeholders()->hash_to_index(p_hash);
386 // can't throw error holding a lock
387 bool child_already_loaded = false;
388 bool throw_circularity_error = false;
389 {
390 MutexLocker mu(SystemDictionary_lock, THREAD);
391 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
392 InstanceKlass* quicksuperk;
393 // to support // loading: if child done loading, just return superclass
394 // if super_name, & class_loader don't match:
395 // if initial define, SD update will give LinkageError
396 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
397 // so we don't throw an exception here.
398 // see: nsk redefclass014 & java.lang.instrument Instrument032
399 if ((childk != NULL ) && (is_superclass) &&
400 ((quicksuperk = childk->java_super()) != NULL) &&
401 ((quicksuperk->name() == super_name) &&
402 (oopDesc::equals(quicksuperk->class_loader(), class_loader())))) {
403 return quicksuperk;
404 } else {
405 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
406 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
407 throw_circularity_error = true;
408 }
409 }
410 if (!throw_circularity_error) {
411 // Be careful not to exit resolve_super
412 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
413 }
414 }
415 if (throw_circularity_error) {
416 ResourceMark rm(THREAD);
417 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
418 }
419
420 // java.lang.Object should have been found above
421 assert(super_name != NULL, "null super class for resolving");
422 // Resolve the super class or interface, check results on return
423 InstanceKlass* superk =
424 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
425 class_loader,
426 protection_domain,
427 THREAD);
428
429 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
430 // It is no longer necessary to keep the placeholder table alive until update_dictionary
431 // or error. GC used to walk the placeholder table as strong roots.
432 // The instanceKlass is kept alive because the class loader is on the stack,
433 // which keeps the loader_data alive, as well as all instanceKlasses in
434 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
435 {
436 MutexLocker mu(SystemDictionary_lock, THREAD);
437 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
438 SystemDictionary_lock->notify_all();
439 }
440 if (HAS_PENDING_EXCEPTION || superk == NULL) {
441 // can null superk
442 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
443 assert(k == NULL || k == superk, "must be");
444 if (k == NULL) {
445 superk = NULL;
446 }
447 }
448
449 return superk;
450 }
451
452 Klass* SystemDictionary::resolve_flattenable_field_or_fail(AllFieldStream* fs,
453 Handle class_loader,
454 Handle protection_domain,
455 bool throw_error,
456 TRAPS) {
457 Symbol* class_name = fs->signature()->fundamental_name(THREAD);
458 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
459 ClassLoaderData* loader_data = class_loader_data(class_loader);
460 unsigned int p_hash = placeholders()->compute_hash(class_name);
461 int p_index = placeholders()->hash_to_index(p_hash);
462 bool throw_circularity_error = false;
463 PlaceholderEntry* oldprobe;
464
465 {
466 MutexLocker mu(SystemDictionary_lock, THREAD);
467 oldprobe = placeholders()->get_entry(p_index, p_hash, class_name, loader_data);
468 if (oldprobe != NULL &&
469 oldprobe->check_seen_thread(THREAD, PlaceholderTable::FLATTENABLE_FIELD)) {
470 throw_circularity_error = true;
471
472 } else {
473 placeholders()->find_and_add(p_index, p_hash, class_name, loader_data,
474 PlaceholderTable::FLATTENABLE_FIELD, NULL, THREAD);
475 }
476 }
477
478 Klass* klass = NULL;
479 if (!throw_circularity_error) {
480 klass = SystemDictionary::resolve_or_fail(class_name, class_loader,
481 protection_domain, true, THREAD);
482 } else {
483 ResourceMark rm(THREAD);
484 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), class_name->as_C_string());
485 }
486
487 {
488 MutexLocker mu(SystemDictionary_lock, THREAD);
489 placeholders()->find_and_remove(p_index, p_hash, class_name, loader_data,
490 PlaceholderTable::FLATTENABLE_FIELD, THREAD);
491 }
492
493 class_name->decrement_refcount();
494 return klass;
495 }
496
497 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
498 Handle class_loader,
499 Handle protection_domain,
500 TRAPS) {
501 if(!has_checkPackageAccess()) return;
502
503 // Now we have to call back to java to check if the initating class has access
504 JavaValue result(T_VOID);
505 LogTarget(Debug, protectiondomain) lt;
506 if (lt.is_enabled()) {
507 ResourceMark rm;
508 // Print out trace information
509 LogStream ls(lt);
510 ls.print_cr("Checking package access");
511 if (class_loader() != NULL) {
512 ls.print("class loader: ");
513 class_loader()->print_value_on(&ls);
514 } else {
515 ls.print_cr("class loader: NULL");
516 }
517 if (protection_domain() != NULL) {
518 ls.print(" protection domain: ");
519 protection_domain()->print_value_on(&ls);
520 } else {
521 ls.print_cr(" protection domain: NULL");
522 }
523 ls.print(" loading: "); klass->print_value_on(&ls);
524 ls.cr();
525 }
526
527 // This handle and the class_loader handle passed in keeps this class from
528 // being unloaded through several GC points.
529 // The class_loader handle passed in is the initiating loader.
530 Handle mirror(THREAD, klass->java_mirror());
531
532 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
533 JavaCalls::call_special(&result,
534 class_loader,
535 system_loader,
536 vmSymbols::checkPackageAccess_name(),
537 vmSymbols::class_protectiondomain_signature(),
538 mirror,
539 protection_domain,
540 THREAD);
541
542 if (HAS_PENDING_EXCEPTION) {
543 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
544 } else {
545 log_debug(protectiondomain)("granted");
546 }
547
548 if (HAS_PENDING_EXCEPTION) return;
549
550 // If no exception has been thrown, we have validated the protection domain
551 // Insert the protection domain of the initiating class into the set.
552 {
553 ClassLoaderData* loader_data = class_loader_data(class_loader);
554 Dictionary* dictionary = loader_data->dictionary();
555
556 Symbol* kn = klass->name();
557 unsigned int d_hash = dictionary->compute_hash(kn);
558
559 MutexLocker mu(SystemDictionary_lock, THREAD);
560 int d_index = dictionary->hash_to_index(d_hash);
561 dictionary->add_protection_domain(d_index, d_hash, klass,
562 protection_domain, THREAD);
563 }
564 }
565
566 // We only get here if this thread finds that another thread
567 // has already claimed the placeholder token for the current operation,
568 // but that other thread either never owned or gave up the
569 // object lock
570 // Waits on SystemDictionary_lock to indicate placeholder table updated
571 // On return, caller must recheck placeholder table state
572 //
573 // We only get here if
574 // 1) custom classLoader, i.e. not bootstrap classloader
575 // 2) custom classLoader has broken the class loader objectLock
576 // so another thread got here in parallel
577 //
578 // lockObject must be held.
579 // Complicated dance due to lock ordering:
580 // Must first release the classloader object lock to
581 // allow initial definer to complete the class definition
582 // and to avoid deadlock
583 // Reclaim classloader lock object with same original recursion count
584 // Must release SystemDictionary_lock after notify, since
585 // class loader lock must be claimed before SystemDictionary_lock
586 // to prevent deadlocks
587 //
588 // The notify allows applications that did an untimed wait() on
589 // the classloader object lock to not hang.
590 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
591 assert_lock_strong(SystemDictionary_lock);
592
593 bool calledholdinglock
594 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
595 assert(calledholdinglock,"must hold lock for notify");
596 assert((!oopDesc::equals(lockObject(), _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
597 ObjectSynchronizer::notifyall(lockObject, THREAD);
598 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
599 SystemDictionary_lock->wait();
600 SystemDictionary_lock->unlock();
601 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
602 SystemDictionary_lock->lock();
603 }
604
605 // If the class in is in the placeholder table, class loading is in progress
606 // For cases where the application changes threads to load classes, it
607 // is critical to ClassCircularity detection that we try loading
608 // the superclass on the same thread internally, so we do parallel
609 // super class loading here.
610 // This also is critical in cases where the original thread gets stalled
611 // even in non-circularity situations.
612 // Note: must call resolve_super_or_fail even if null super -
613 // to force placeholder entry creation for this class for circularity detection
614 // Caller must check for pending exception
615 // Returns non-null Klass* if other thread has completed load
616 // and we are done,
617 // If return null Klass* and no pending exception, the caller must load the class
618 InstanceKlass* SystemDictionary::handle_parallel_super_load(
619 Symbol* name, Symbol* superclassname, Handle class_loader,
620 Handle protection_domain, Handle lockObject, TRAPS) {
621
622 ClassLoaderData* loader_data = class_loader_data(class_loader);
623 Dictionary* dictionary = loader_data->dictionary();
624 unsigned int d_hash = dictionary->compute_hash(name);
625 unsigned int p_hash = placeholders()->compute_hash(name);
626 int p_index = placeholders()->hash_to_index(p_hash);
627
628 // superk is not used, resolve_super called for circularity check only
629 // This code is reached in two situations. One if this thread
630 // is loading the same class twice (e.g. ClassCircularity, or
631 // java.lang.instrument).
632 // The second is if another thread started the resolve_super first
633 // and has not yet finished.
634 // In both cases the original caller will clean up the placeholder
635 // entry on error.
636 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
637 superclassname,
638 class_loader,
639 protection_domain,
640 true,
641 CHECK_NULL);
642
643 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
644 // Serial class loaders and bootstrap classloader do wait for superclass loads
645 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
646 MutexLocker mu(SystemDictionary_lock, THREAD);
647 // Check if classloading completed while we were loading superclass or waiting
648 return find_class(d_hash, name, dictionary);
649 }
650
651 // must loop to both handle other placeholder updates
652 // and spurious notifications
653 bool super_load_in_progress = true;
654 PlaceholderEntry* placeholder;
655 while (super_load_in_progress) {
656 MutexLocker mu(SystemDictionary_lock, THREAD);
657 // Check if classloading completed while we were loading superclass or waiting
658 InstanceKlass* check = find_class(d_hash, name, dictionary);
659 if (check != NULL) {
660 // Klass is already loaded, so just return it
661 return check;
662 } else {
663 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
664 if (placeholder && placeholder->super_load_in_progress() ){
665 // We only get here if the application has released the
666 // classloader lock when another thread was in the middle of loading a
667 // superclass/superinterface for this class, and now
668 // this thread is also trying to load this class.
669 // To minimize surprises, the first thread that started to
670 // load a class should be the one to complete the loading
671 // with the classfile it initially expected.
672 // This logic has the current thread wait once it has done
673 // all the superclass/superinterface loading it can, until
674 // the original thread completes the class loading or fails
675 // If it completes we will use the resulting InstanceKlass
676 // which we will find below in the systemDictionary.
677 // We also get here for parallel bootstrap classloader
678 if (class_loader.is_null()) {
679 SystemDictionary_lock->wait();
680 } else {
681 double_lock_wait(lockObject, THREAD);
682 }
683 } else {
684 // If not in SD and not in PH, other thread's load must have failed
685 super_load_in_progress = false;
686 }
687 }
688 }
689 return NULL;
690 }
691
692 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
693 assert(event != NULL, "invariant");
694 assert(k != NULL, "invariant");
695 assert(event->should_commit(), "invariant");
696 event->set_loadedClass(k);
697 event->set_definingClassLoader(k->class_loader_data());
698 event->set_initiatingClassLoader(init_cld);
699 event->commit();
700 }
701
702
703 // Be careful when modifying this code: once you have run
704 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
705 // you need to find_and_remove it before returning.
706 // So be careful to not exit with a CHECK_ macro betweeen these calls.
707 //
708 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
709 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
710 Handle class_loader,
711 Handle protection_domain,
712 TRAPS) {
713 assert(name != NULL && !FieldType::is_array(name) &&
714 !FieldType::is_obj(name) && !FieldType::is_valuetype(name), "invalid class name");
715
716 EventClassLoad class_load_start_event;
717
718 HandleMark hm(THREAD);
719
720 // Fix for 4474172; see evaluation for more details
721 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
722 ClassLoaderData* loader_data = register_loader(class_loader);
723 Dictionary* dictionary = loader_data->dictionary();
724 unsigned int d_hash = dictionary->compute_hash(name);
725
726 // Do lookup to see if class already exist and the protection domain
727 // has the right access
728 // This call uses find which checks protection domain already matches
729 // All subsequent calls use find_class, and set has_loaded_class so that
730 // before we return a result we call out to java to check for valid protection domain
731 // to allow returning the Klass* and add it to the pd_set if it is valid
732 {
733 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
734 if (probe != NULL) return probe;
735 }
736
737 // Non-bootstrap class loaders will call out to class loader and
738 // define via jvm/jni_DefineClass which will acquire the
739 // class loader object lock to protect against multiple threads
740 // defining the class in parallel by accident.
741 // This lock must be acquired here so the waiter will find
742 // any successful result in the SystemDictionary and not attempt
743 // the define.
744 // ParallelCapable Classloaders and the bootstrap classloader
745 // do not acquire lock here.
746 bool DoObjectLock = true;
747 if (is_parallelCapable(class_loader)) {
748 DoObjectLock = false;
749 }
750
751 unsigned int p_hash = placeholders()->compute_hash(name);
752 int p_index = placeholders()->hash_to_index(p_hash);
753
754 // Class is not in SystemDictionary so we have to do loading.
755 // Make sure we are synchronized on the class loader before we proceed
756 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
757 check_loader_lock_contention(lockObject, THREAD);
758 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
759
760 // Check again (after locking) if class already exist in SystemDictionary
761 bool class_has_been_loaded = false;
762 bool super_load_in_progress = false;
763 bool havesupername = false;
764 InstanceKlass* k = NULL;
765 PlaceholderEntry* placeholder;
766 Symbol* superclassname = NULL;
767
768 assert(THREAD->can_call_java(),
769 "can not load classes with compiler thread: class=%s, classloader=%s",
770 name->as_C_string(),
771 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
772 {
773 MutexLocker mu(SystemDictionary_lock, THREAD);
774 InstanceKlass* check = find_class(d_hash, name, dictionary);
775 if (check != NULL) {
776 // InstanceKlass is already loaded, so just return it
777 class_has_been_loaded = true;
778 k = check;
779 } else {
780 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
781 if (placeholder && placeholder->super_load_in_progress()) {
782 super_load_in_progress = true;
783 if (placeholder->havesupername() == true) {
784 superclassname = placeholder->supername();
785 havesupername = true;
786 }
787 }
788 }
789 }
790
791 // If the class is in the placeholder table, class loading is in progress
792 if (super_load_in_progress && havesupername==true) {
793 k = handle_parallel_super_load(name,
794 superclassname,
795 class_loader,
796 protection_domain,
797 lockObject, THREAD);
798 if (HAS_PENDING_EXCEPTION) {
799 return NULL;
800 }
801 if (k != NULL) {
802 class_has_been_loaded = true;
803 }
804 }
805
806 bool throw_circularity_error = false;
807 if (!class_has_been_loaded) {
808 bool load_instance_added = false;
809
810 // add placeholder entry to record loading instance class
811 // Five cases:
812 // All cases need to prevent modifying bootclasssearchpath
813 // in parallel with a classload of same classname
814 // Redefineclasses uses existence of the placeholder for the duration
815 // of the class load to prevent concurrent redefinition of not completely
816 // defined classes.
817 // case 1. traditional classloaders that rely on the classloader object lock
818 // - no other need for LOAD_INSTANCE
819 // case 2. traditional classloaders that break the classloader object lock
820 // as a deadlock workaround. Detection of this case requires that
821 // this check is done while holding the classloader object lock,
822 // and that lock is still held when calling classloader's loadClass.
823 // For these classloaders, we ensure that the first requestor
824 // completes the load and other requestors wait for completion.
825 // case 3. Bootstrap classloader - don't own objectLocker
826 // This classloader supports parallelism at the classloader level,
827 // but only allows a single load of a class/classloader pair.
828 // No performance benefit and no deadlock issues.
829 // case 4. parallelCapable user level classloaders - without objectLocker
830 // Allow parallel classloading of a class/classloader pair
831
832 {
833 MutexLocker mu(SystemDictionary_lock, THREAD);
834 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
835 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
836 if (oldprobe) {
837 // only need check_seen_thread once, not on each loop
838 // 6341374 java/lang/Instrument with -Xcomp
839 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
840 throw_circularity_error = true;
841 } else {
842 // case 1: traditional: should never see load_in_progress.
843 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
844
845 // case 3: bootstrap classloader: prevent futile classloading,
846 // wait on first requestor
847 if (class_loader.is_null()) {
848 SystemDictionary_lock->wait();
849 } else {
850 // case 2: traditional with broken classloader lock. wait on first
851 // requestor.
852 double_lock_wait(lockObject, THREAD);
853 }
854 // Check if classloading completed while we were waiting
855 InstanceKlass* check = find_class(d_hash, name, dictionary);
856 if (check != NULL) {
857 // Klass is already loaded, so just return it
858 k = check;
859 class_has_been_loaded = true;
860 }
861 // check if other thread failed to load and cleaned up
862 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
863 }
864 }
865 }
866 }
867 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
868 // case 4: parallelCapable: allow competing threads to try
869 // LOAD_INSTANCE in parallel
870
871 if (!throw_circularity_error && !class_has_been_loaded) {
872 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
873 load_instance_added = true;
874 // For class loaders that do not acquire the classloader object lock,
875 // if they did not catch another thread holding LOAD_INSTANCE,
876 // need a check analogous to the acquire ObjectLocker/find_class
877 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
878 // one final check if the load has already completed
879 // class loaders holding the ObjectLock shouldn't find the class here
880 InstanceKlass* check = find_class(d_hash, name, dictionary);
881 if (check != NULL) {
882 // Klass is already loaded, so return it after checking/adding protection domain
883 k = check;
884 class_has_been_loaded = true;
885 }
886 }
887 }
888
889 // must throw error outside of owning lock
890 if (throw_circularity_error) {
891 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
892 ResourceMark rm(THREAD);
893 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
894 }
895
896 if (!class_has_been_loaded) {
897
898 // Do actual loading
899 k = load_instance_class(name, class_loader, THREAD);
900
901 // If everything was OK (no exceptions, no null return value), and
902 // class_loader is NOT the defining loader, do a little more bookkeeping.
903 if (!HAS_PENDING_EXCEPTION && k != NULL &&
904 !oopDesc::equals(k->class_loader(), class_loader())) {
905
906 check_constraints(d_hash, k, class_loader, false, THREAD);
907
908 // Need to check for a PENDING_EXCEPTION again; check_constraints
909 // can throw but we may have to remove entry from the placeholder table below.
910 if (!HAS_PENDING_EXCEPTION) {
911 // Record dependency for non-parent delegation.
912 // This recording keeps the defining class loader of the klass (k) found
913 // from being unloaded while the initiating class loader is loaded
914 // even if the reference to the defining class loader is dropped
915 // before references to the initiating class loader.
916 loader_data->record_dependency(k);
917
918 { // Grabbing the Compile_lock prevents systemDictionary updates
919 // during compilations.
920 MutexLocker mu(Compile_lock, THREAD);
921 update_dictionary(d_hash, p_index, p_hash,
922 k, class_loader, THREAD);
923 }
924
925 if (JvmtiExport::should_post_class_load()) {
926 Thread *thread = THREAD;
927 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
928 JvmtiExport::post_class_load((JavaThread *) thread, k);
929 }
930 }
931 }
932 } // load_instance_class
933
934 if (load_instance_added == true) {
935 // clean up placeholder entries for LOAD_INSTANCE success or error
936 // This brackets the SystemDictionary updates for both defining
937 // and initiating loaders
938 MutexLocker mu(SystemDictionary_lock, THREAD);
939 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
940 SystemDictionary_lock->notify_all();
941 }
942 }
943
944 if (HAS_PENDING_EXCEPTION || k == NULL) {
945 return NULL;
946 }
947 if (class_load_start_event.should_commit()) {
948 post_class_load_event(&class_load_start_event, k, loader_data);
949 }
950 #ifdef ASSERT
951 {
952 ClassLoaderData* loader_data = k->class_loader_data();
953 MutexLocker mu(SystemDictionary_lock, THREAD);
954 InstanceKlass* kk = find_class(name, loader_data);
955 assert(kk == k, "should be present in dictionary");
956 }
957 #endif
958
959 // return if the protection domain in NULL
960 if (protection_domain() == NULL) return k;
961
962 // Check the protection domain has the right access
963 if (dictionary->is_valid_protection_domain(d_hash, name,
964 protection_domain)) {
965 return k;
966 }
967
968 // Verify protection domain. If it fails an exception is thrown
969 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
970
971 return k;
972 }
973
974
975 // This routine does not lock the system dictionary.
976 //
977 // Since readers don't hold a lock, we must make sure that system
978 // dictionary entries are only removed at a safepoint (when only one
979 // thread is running), and are added to in a safe way (all links must
980 // be updated in an MT-safe manner).
981 //
982 // Callers should be aware that an entry could be added just after
983 // _dictionary->bucket(index) is read here, so the caller will not see
984 // the new entry.
985
986 Klass* SystemDictionary::find(Symbol* class_name,
987 Handle class_loader,
988 Handle protection_domain,
989 TRAPS) {
990
991 // The result of this call should be consistent with the result
992 // of the call to resolve_instance_class_or_null().
993 // See evaluation 6790209 and 4474172 for more details.
994 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
995 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
996
997 if (loader_data == NULL) {
998 // If the ClassLoaderData has not been setup,
999 // then the class loader has no entries in the dictionary.
1000 return NULL;
1001 }
1002
1003 Dictionary* dictionary = loader_data->dictionary();
1004 unsigned int d_hash = dictionary->compute_hash(class_name);
1005 return dictionary->find(d_hash, class_name,
1006 protection_domain);
1007 }
1008
1009
1010 // Look for a loaded instance or array klass by name. Do not do any loading.
1011 // return NULL in case of error.
1012 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1013 Handle class_loader,
1014 Handle protection_domain,
1015 TRAPS) {
1016 Klass* k = NULL;
1017 assert(class_name != NULL, "class name must be non NULL");
1018
1019 if (FieldType::is_array(class_name)) {
1020 // The name refers to an array. Parse the name.
1021 // dimension and object_key in FieldArrayInfo are assigned as a
1022 // side-effect of this call
1023 FieldArrayInfo fd;
1024 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
1025 if (t != T_OBJECT && t != T_VALUETYPE) {
1026 k = Universe::typeArrayKlassObj(t);
1027 } else {
1028 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
1029 }
1030 if (k != NULL) {
1031 k = k->array_klass_or_null(fd.dimension());
1032 }
1033 } else {
1034 k = find(class_name, class_loader, protection_domain, THREAD);
1035 }
1036 return k;
1037 }
1038
1039 // Note: this method is much like resolve_from_stream, but
1040 // does not publish the classes via the SystemDictionary.
1041 // Handles unsafe_DefineAnonymousClass and redefineclasses
1042 // RedefinedClasses do not add to the class hierarchy
1043 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1044 Handle class_loader,
1045 Handle protection_domain,
1046 ClassFileStream* st,
1047 const InstanceKlass* unsafe_anonymous_host,
1048 GrowableArray<Handle>* cp_patches,
1049 TRAPS) {
1050
1051 EventClassLoad class_load_start_event;
1052
1053 ClassLoaderData* loader_data;
1054 if (unsafe_anonymous_host != NULL) {
1055 // Create a new CLD for an unsafe anonymous class, that uses the same class loader
1056 // as the unsafe_anonymous_host
1057 guarantee(oopDesc::equals(unsafe_anonymous_host->class_loader(), class_loader()), "should be the same");
1058 loader_data = ClassLoaderData::unsafe_anonymous_class_loader_data(class_loader);
1059 } else {
1060 loader_data = ClassLoaderData::class_loader_data(class_loader());
1061 }
1062
1063 assert(st != NULL, "invariant");
1064 assert(st->need_verify(), "invariant");
1065
1066 // Parse stream and create a klass.
1067 // Note that we do this even though this klass might
1068 // already be present in the SystemDictionary, otherwise we would not
1069 // throw potential ClassFormatErrors.
1070
1071 InstanceKlass* k = KlassFactory::create_from_stream(st,
1072 class_name,
1073 loader_data,
1074 protection_domain,
1075 unsafe_anonymous_host,
1076 cp_patches,
1077 CHECK_NULL);
1078
1079 if (unsafe_anonymous_host != NULL && k != NULL) {
1080 // Unsafe anonymous classes must update ClassLoaderData holder (was unsafe_anonymous_host loader)
1081 // so that they can be unloaded when the mirror is no longer referenced.
1082 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1083
1084 {
1085 MutexLocker mu_r(Compile_lock, THREAD);
1086
1087 // Add to class hierarchy, initialize vtables, and do possible
1088 // deoptimizations.
1089 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1090
1091 // But, do not add to dictionary.
1092
1093 // compiled code dependencies need to be validated anyway
1094 notice_modification();
1095 }
1096
1097 // Rewrite and patch constant pool here.
1098 k->link_class(CHECK_NULL);
1099 if (cp_patches != NULL) {
1100 k->constants()->patch_resolved_references(cp_patches);
1101 }
1102
1103 // If it's anonymous, initialize it now, since nobody else will.
1104 k->eager_initialize(CHECK_NULL);
1105
1106 // notify jvmti
1107 if (JvmtiExport::should_post_class_load()) {
1108 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1109 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1110 }
1111 if (class_load_start_event.should_commit()) {
1112 post_class_load_event(&class_load_start_event, k, loader_data);
1113 }
1114 }
1115 assert(unsafe_anonymous_host != NULL || NULL == cp_patches,
1116 "cp_patches only found with unsafe_anonymous_host");
1117
1118 return k;
1119 }
1120
1121 // Add a klass to the system from a stream (called by jni_DefineClass and
1122 // JVM_DefineClass).
1123 // Note: class_name can be NULL. In that case we do not know the name of
1124 // the class until we have parsed the stream.
1125
1126 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1127 Handle class_loader,
1128 Handle protection_domain,
1129 ClassFileStream* st,
1130 TRAPS) {
1131
1132 HandleMark hm(THREAD);
1133
1134 // Classloaders that support parallelism, e.g. bootstrap classloader,
1135 // do not acquire lock here
1136 bool DoObjectLock = true;
1137 if (is_parallelCapable(class_loader)) {
1138 DoObjectLock = false;
1139 }
1140
1141 ClassLoaderData* loader_data = register_loader(class_loader);
1142
1143 // Make sure we are synchronized on the class loader before we proceed
1144 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1145 check_loader_lock_contention(lockObject, THREAD);
1146 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1147
1148 assert(st != NULL, "invariant");
1149
1150 // Parse the stream and create a klass.
1151 // Note that we do this even though this klass might
1152 // already be present in the SystemDictionary, otherwise we would not
1153 // throw potential ClassFormatErrors.
1154 InstanceKlass* k = NULL;
1155
1156 #if INCLUDE_CDS
1157 if (!DumpSharedSpaces) {
1158 k = SystemDictionaryShared::lookup_from_stream(class_name,
1159 class_loader,
1160 protection_domain,
1161 st,
1162 CHECK_NULL);
1163 }
1164 #endif
1165
1166 if (k == NULL) {
1167 if (st->buffer() == NULL) {
1168 return NULL;
1169 }
1170 k = KlassFactory::create_from_stream(st,
1171 class_name,
1172 loader_data,
1173 protection_domain,
1174 NULL, // unsafe_anonymous_host
1175 NULL, // cp_patches
1176 CHECK_NULL);
1177 }
1178
1179 assert(k != NULL, "no klass created");
1180 Symbol* h_name = k->name();
1181 assert(class_name == NULL || class_name == h_name, "name mismatch");
1182
1183 // Add class just loaded
1184 // If a class loader supports parallel classloading handle parallel define requests
1185 // find_or_define_instance_class may return a different InstanceKlass
1186 if (is_parallelCapable(class_loader)) {
1187 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1188 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1189 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1190 assert(defined_k != NULL, "Should have a klass if there's no exception");
1191 loader_data->add_to_deallocate_list(k);
1192 k = defined_k;
1193 }
1194 } else {
1195 define_instance_class(k, THREAD);
1196 }
1197
1198 // If defining the class throws an exception register 'k' for cleanup.
1199 if (HAS_PENDING_EXCEPTION) {
1200 assert(k != NULL, "Must have an instance klass here!");
1201 loader_data->add_to_deallocate_list(k);
1202 return NULL;
1203 }
1204
1205 // Make sure we have an entry in the SystemDictionary on success
1206 debug_only( {
1207 MutexLocker mu(SystemDictionary_lock, THREAD);
1208
1209 Klass* check = find_class(h_name, k->class_loader_data());
1210 assert(check == k, "should be present in the dictionary");
1211 } );
1212
1213 return k;
1214 }
1215
1216 #if INCLUDE_CDS
1217 // Load a class for boot loader from the shared spaces. This also
1218 // forces the super class and all interfaces to be loaded.
1219 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1220 TRAPS) {
1221 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1222 if (ik != NULL && ik->is_shared_boot_class()) {
1223 return load_shared_class(ik, Handle(), Handle(), NULL, THREAD);
1224 }
1225 return NULL;
1226 }
1227
1228 // Check if a shared class can be loaded by the specific classloader:
1229 //
1230 // NULL classloader:
1231 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1232 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1233 // be defined in an unnamed module.
1234 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1235 InstanceKlass* ik,
1236 Handle class_loader, TRAPS) {
1237 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1238 "Cannot use sharing if java.base is patched");
1239 ResourceMark rm;
1240 int path_index = ik->shared_classpath_index();
1241 ClassLoaderData* loader_data = class_loader_data(class_loader);
1242 if (path_index < 0) {
1243 // path_index < 0 indicates that the class is intended for a custom loader
1244 // and should not be loaded by boot/platform/app loaders
1245 if (loader_data->is_builtin_class_loader_data()) {
1246 return false;
1247 } else {
1248 return true;
1249 }
1250 }
1251 SharedClassPathEntry* ent =
1252 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1253 if (!Universe::is_module_initialized()) {
1254 assert(ent != NULL && ent->is_modules_image(),
1255 "Loading non-bootstrap classes before the module system is initialized");
1256 assert(class_loader.is_null(), "sanity");
1257 return true;
1258 }
1259 // Get the pkg_entry from the classloader
1260 TempNewSymbol pkg_name = NULL;
1261 PackageEntry* pkg_entry = NULL;
1262 ModuleEntry* mod_entry = NULL;
1263 const char* pkg_string = NULL;
1264 pkg_name = InstanceKlass::package_from_name(class_name, CHECK_false);
1265 if (pkg_name != NULL) {
1266 pkg_string = pkg_name->as_C_string();
1267 if (loader_data != NULL) {
1268 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1269 }
1270 if (pkg_entry != NULL) {
1271 mod_entry = pkg_entry->module();
1272 }
1273 }
1274
1275 // If the archived class is from a module that has been patched at runtime,
1276 // the class cannot be loaded from the archive.
1277 if (mod_entry != NULL && mod_entry->is_patched()) {
1278 return false;
1279 }
1280
1281 if (class_loader.is_null()) {
1282 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1283 // The NULL classloader can load archived class originated from the
1284 // "modules" jimage and the -Xbootclasspath/a. For class from the
1285 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1286 // by the NULL classloader.
1287 if (mod_entry != NULL) {
1288 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1289 // ModuleEntry's location agrees with the archived class' origination.
1290 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1291 return true; // Module class from the "module" jimage
1292 }
1293 }
1294
1295 // If the archived class is not from the "module" jimage, the class can be
1296 // loaded by the NULL classloader if
1297 //
1298 // 1. the class is from the unamed package
1299 // 2. or, the class is not from a module defined in the NULL classloader
1300 // 3. or, the class is from an unamed module
1301 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1302 // the class is from the -Xbootclasspath/a
1303 if (pkg_string == NULL ||
1304 pkg_entry == NULL ||
1305 pkg_entry->in_unnamed_module()) {
1306 assert(mod_entry == NULL ||
1307 mod_entry == loader_data->unnamed_module(),
1308 "the unnamed module is not defined in the classloader");
1309 return true;
1310 }
1311 }
1312 return false;
1313 } else {
1314 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1315 ik, class_loader, pkg_string, pkg_name,
1316 pkg_entry, mod_entry, CHECK_(false));
1317 return res;
1318 }
1319 }
1320
1321 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1322 Handle class_loader,
1323 Handle protection_domain,
1324 const ClassFileStream *cfs,
1325 TRAPS) {
1326
1327 if (ik != NULL) {
1328 Symbol* class_name = ik->name();
1329
1330 bool visible = is_shared_class_visible(
1331 class_name, ik, class_loader, CHECK_NULL);
1332 if (!visible) {
1333 return NULL;
1334 }
1335
1336 // Resolve the superclass and interfaces. They must be the same
1337 // as in dump time, because the layout of <ik> depends on
1338 // the specific layout of ik->super() and ik->local_interfaces().
1339 //
1340 // If unexpected superclass or interfaces are found, we cannot
1341 // load <ik> from the shared archive.
1342
1343 if (ik->super() != NULL) {
1344 Symbol* cn = ik->super()->name();
1345 Klass *s = resolve_super_or_fail(class_name, cn,
1346 class_loader, protection_domain, true, CHECK_NULL);
1347 if (s != ik->super()) {
1348 // The dynamically resolved super class is not the same as the one we used during dump time,
1349 // so we cannot use ik.
1350 return NULL;
1351 } else {
1352 assert(s->is_shared(), "must be");
1353 }
1354 }
1355
1356 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1357 int num_interfaces = interfaces->length();
1358 for (int index = 0; index < num_interfaces; index++) {
1359 InstanceKlass* k = interfaces->at(index);
1360 Symbol* name = k->name();
1361 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_NULL);
1362 if (k != i) {
1363 // The dynamically resolved interface class is not the same as the one we used during dump time,
1364 // so we cannot use ik.
1365 return NULL;
1366 } else {
1367 assert(i->is_shared(), "must be");
1368 }
1369 }
1370
1371 InstanceKlass* new_ik = KlassFactory::check_shared_class_file_load_hook(
1372 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1373 if (new_ik != NULL) {
1374 // The class is changed by CFLH. Return the new class. The shared class is
1375 // not used.
1376 return new_ik;
1377 }
1378
1379 // Adjust methods to recover missing data. They need addresses for
1380 // interpreter entry points and their default native method address
1381 // must be reset.
1382
1383 // Updating methods must be done under a lock so multiple
1384 // threads don't update these in parallel
1385 //
1386 // Shared classes are all currently loaded by either the bootstrap or
1387 // internal parallel class loaders, so this will never cause a deadlock
1388 // on a custom class loader lock.
1389
1390 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1391 {
1392 HandleMark hm(THREAD);
1393 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1394 check_loader_lock_contention(lockObject, THREAD);
1395 ObjectLocker ol(lockObject, THREAD, true);
1396 // prohibited package check assumes all classes loaded from archive call
1397 // restore_unshareable_info which calls ik->set_package()
1398 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_NULL);
1399 }
1400
1401 ik->print_class_load_logging(loader_data, NULL, NULL);
1402
1403 // For boot loader, ensure that GetSystemPackage knows that a class in this
1404 // package was loaded.
1405 if (class_loader.is_null()) {
1406 int path_index = ik->shared_classpath_index();
1407 ResourceMark rm;
1408 ClassLoader::add_package(ik->name()->as_C_string(), path_index, THREAD);
1409 }
1410
1411 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1412 // Only dump the classes that can be stored into CDS archive
1413 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1414 ResourceMark rm(THREAD);
1415 classlist_file->print_cr("%s", ik->name()->as_C_string());
1416 classlist_file->flush();
1417 }
1418 }
1419
1420 // notify a class loaded from shared object
1421 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1422
1423 ik->set_has_passed_fingerprint_check(false);
1424 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1425 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1426 uint64_t cds_fp = ik->get_stored_fingerprint();
1427 if (aot_fp != 0 && aot_fp == cds_fp) {
1428 // This class matches with a class saved in an AOT library
1429 ik->set_has_passed_fingerprint_check(true);
1430 } else {
1431 ResourceMark rm;
1432 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1433 }
1434 }
1435 }
1436 return ik;
1437 }
1438 #endif // INCLUDE_CDS
1439
1440 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1441
1442 if (class_loader.is_null()) {
1443 ResourceMark rm;
1444 PackageEntry* pkg_entry = NULL;
1445 bool search_only_bootloader_append = false;
1446 ClassLoaderData *loader_data = class_loader_data(class_loader);
1447
1448 // Find the package in the boot loader's package entry table.
1449 TempNewSymbol pkg_name = InstanceKlass::package_from_name(class_name, CHECK_NULL);
1450 if (pkg_name != NULL) {
1451 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1452 }
1453
1454 // Prior to attempting to load the class, enforce the boot loader's
1455 // visibility boundaries.
1456 if (!Universe::is_module_initialized()) {
1457 // During bootstrapping, prior to module initialization, any
1458 // class attempting to be loaded must be checked against the
1459 // java.base packages in the boot loader's PackageEntryTable.
1460 // No class outside of java.base is allowed to be loaded during
1461 // this bootstrapping window.
1462 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1463 // Class is either in the unnamed package or in
1464 // a named package within the unnamed module. Either
1465 // case is outside of java.base, do not attempt to
1466 // load the class post java.base definition. If
1467 // java.base has not been defined, let the class load
1468 // and its package will be checked later by
1469 // ModuleEntryTable::verify_javabase_packages.
1470 if (ModuleEntryTable::javabase_defined()) {
1471 return NULL;
1472 }
1473 } else {
1474 // Check that the class' package is defined within java.base.
1475 ModuleEntry* mod_entry = pkg_entry->module();
1476 Symbol* mod_entry_name = mod_entry->name();
1477 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1478 return NULL;
1479 }
1480 }
1481 } else {
1482 // After the module system has been initialized, check if the class'
1483 // package is in a module defined to the boot loader.
1484 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1485 // Class is either in the unnamed package, in a named package
1486 // within a module not defined to the boot loader or in a
1487 // a named package within the unnamed module. In all cases,
1488 // limit visibility to search for the class only in the boot
1489 // loader's append path.
1490 search_only_bootloader_append = true;
1491 }
1492 }
1493
1494 // Prior to bootstrapping's module initialization, never load a class outside
1495 // of the boot loader's module path
1496 assert(Universe::is_module_initialized() ||
1497 !search_only_bootloader_append,
1498 "Attempt to load a class outside of boot loader's module path");
1499
1500 // Search for classes in the CDS archive.
1501 InstanceKlass* k = NULL;
1502 {
1503 #if INCLUDE_CDS
1504 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1505 k = load_shared_boot_class(class_name, THREAD);
1506 #endif
1507 }
1508
1509 if (k == NULL) {
1510 // Use VM class loader
1511 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1512 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1513 }
1514
1515 // find_or_define_instance_class may return a different InstanceKlass
1516 if (k != NULL) {
1517 InstanceKlass* defined_k =
1518 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1519 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1520 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1521 assert(defined_k != NULL, "Should have a klass if there's no exception");
1522 loader_data->add_to_deallocate_list(k);
1523 k = defined_k;
1524 } else if (HAS_PENDING_EXCEPTION) {
1525 loader_data->add_to_deallocate_list(k);
1526 return NULL;
1527 }
1528 }
1529 return k;
1530 } else {
1531 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1532 ResourceMark rm(THREAD);
1533
1534 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1535 JavaThread* jt = (JavaThread*) THREAD;
1536
1537 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1538 ClassLoader::perf_app_classload_selftime(),
1539 ClassLoader::perf_app_classload_count(),
1540 jt->get_thread_stat()->perf_recursion_counts_addr(),
1541 jt->get_thread_stat()->perf_timers_addr(),
1542 PerfClassTraceTime::CLASS_LOAD);
1543
1544 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1545 // Translate to external class name format, i.e., convert '/' chars to '.'
1546 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1547
1548 JavaValue result(T_OBJECT);
1549
1550 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1551
1552 // Call public unsynchronized loadClass(String) directly for all class loaders.
1553 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1554 // acquire a class-name based lock rather than the class loader object lock.
1555 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1556 JavaCalls::call_virtual(&result,
1557 class_loader,
1558 spec_klass,
1559 vmSymbols::loadClass_name(),
1560 vmSymbols::string_class_signature(),
1561 string,
1562 CHECK_NULL);
1563
1564 assert(result.get_type() == T_OBJECT, "just checking");
1565 oop obj = (oop) result.get_jobject();
1566
1567 // Primitive classes return null since forName() can not be
1568 // used to obtain any of the Class objects representing primitives or void
1569 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1570 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1571 // For user defined Java class loaders, check that the name returned is
1572 // the same as that requested. This check is done for the bootstrap
1573 // loader when parsing the class file.
1574 if (class_name == k->name()) {
1575 return k;
1576 }
1577 }
1578 // Class is not found or has the wrong name, return NULL
1579 return NULL;
1580 }
1581 }
1582
1583 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1584 EventClassDefine event;
1585 if (event.should_commit()) {
1586 event.set_definedClass(k);
1587 event.set_definingClassLoader(def_cld);
1588 event.commit();
1589 }
1590 }
1591
1592 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1593
1594 HandleMark hm(THREAD);
1595 ClassLoaderData* loader_data = k->class_loader_data();
1596 Handle class_loader_h(THREAD, loader_data->class_loader());
1597
1598 // for bootstrap and other parallel classloaders don't acquire lock,
1599 // use placeholder token
1600 // If a parallelCapable class loader calls define_instance_class instead of
1601 // find_or_define_instance_class to get here, we have a timing
1602 // hole with systemDictionary updates and check_constraints
1603 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1604 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1605 compute_loader_lock_object(class_loader_h, THREAD)),
1606 "define called without lock");
1607 }
1608
1609 // Check class-loading constraints. Throw exception if violation is detected.
1610 // Grabs and releases SystemDictionary_lock
1611 // The check_constraints/find_class call and update_dictionary sequence
1612 // must be "atomic" for a specific class/classloader pair so we never
1613 // define two different instanceKlasses for that class/classloader pair.
1614 // Existing classloaders will call define_instance_class with the
1615 // classloader lock held
1616 // Parallel classloaders will call find_or_define_instance_class
1617 // which will require a token to perform the define class
1618 Symbol* name_h = k->name();
1619 Dictionary* dictionary = loader_data->dictionary();
1620 unsigned int d_hash = dictionary->compute_hash(name_h);
1621 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1622
1623 // Register class just loaded with class loader (placed in Vector)
1624 // Note we do this before updating the dictionary, as this can
1625 // fail with an OutOfMemoryError (if it does, we will *not* put this
1626 // class in the dictionary and will not update the class hierarchy).
1627 // JVMTI FollowReferences needs to find the classes this way.
1628 if (k->class_loader() != NULL) {
1629 methodHandle m(THREAD, Universe::loader_addClass_method());
1630 JavaValue result(T_VOID);
1631 JavaCallArguments args(class_loader_h);
1632 args.push_oop(Handle(THREAD, k->java_mirror()));
1633 JavaCalls::call(&result, m, &args, CHECK);
1634 }
1635
1636 // Add the new class. We need recompile lock during update of CHA.
1637 {
1638 unsigned int p_hash = placeholders()->compute_hash(name_h);
1639 int p_index = placeholders()->hash_to_index(p_hash);
1640
1641 MutexLocker mu_r(Compile_lock, THREAD);
1642
1643 // Add to class hierarchy, initialize vtables, and do possible
1644 // deoptimizations.
1645 add_to_hierarchy(k, CHECK); // No exception, but can block
1646
1647 // Add to systemDictionary - so other classes can see it.
1648 // Grabs and releases SystemDictionary_lock
1649 update_dictionary(d_hash, p_index, p_hash,
1650 k, class_loader_h, THREAD);
1651 }
1652 k->eager_initialize(THREAD);
1653
1654 // notify jvmti
1655 if (JvmtiExport::should_post_class_load()) {
1656 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1657 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1658
1659 }
1660 post_class_define_event(k, loader_data);
1661 }
1662
1663 // Support parallel classloading
1664 // All parallel class loaders, including bootstrap classloader
1665 // lock a placeholder entry for this class/class_loader pair
1666 // to allow parallel defines of different classes for this class loader
1667 // With AllowParallelDefine flag==true, in case they do not synchronize around
1668 // FindLoadedClass/DefineClass, calls, we check for parallel
1669 // loading for them, wait if a defineClass is in progress
1670 // and return the initial requestor's results
1671 // This flag does not apply to the bootstrap classloader.
1672 // With AllowParallelDefine flag==false, call through to define_instance_class
1673 // which will throw LinkageError: duplicate class definition.
1674 // False is the requested default.
1675 // For better performance, the class loaders should synchronize
1676 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1677 // potentially waste time reading and parsing the bytestream.
1678 // Note: VM callers should ensure consistency of k/class_name,class_loader
1679 // Be careful when modifying this code: once you have run
1680 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1681 // you need to find_and_remove it before returning.
1682 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1683 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1684 InstanceKlass* k, TRAPS) {
1685
1686 Symbol* name_h = k->name(); // passed in class_name may be null
1687 ClassLoaderData* loader_data = class_loader_data(class_loader);
1688 Dictionary* dictionary = loader_data->dictionary();
1689
1690 unsigned int d_hash = dictionary->compute_hash(name_h);
1691
1692 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1693 unsigned int p_hash = placeholders()->compute_hash(name_h);
1694 int p_index = placeholders()->hash_to_index(p_hash);
1695 PlaceholderEntry* probe;
1696
1697 {
1698 MutexLocker mu(SystemDictionary_lock, THREAD);
1699 // First check if class already defined
1700 if (is_parallelDefine(class_loader)) {
1701 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1702 if (check != NULL) {
1703 return check;
1704 }
1705 }
1706
1707 // Acquire define token for this class/classloader
1708 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1709 // Wait if another thread defining in parallel
1710 // All threads wait - even those that will throw duplicate class: otherwise
1711 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1712 // if other thread has not finished updating dictionary
1713 while (probe->definer() != NULL) {
1714 SystemDictionary_lock->wait();
1715 }
1716 // Only special cases allow parallel defines and can use other thread's results
1717 // Other cases fall through, and may run into duplicate defines
1718 // caught by finding an entry in the SystemDictionary
1719 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1720 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1721 SystemDictionary_lock->notify_all();
1722 #ifdef ASSERT
1723 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1724 assert(check != NULL, "definer missed recording success");
1725 #endif
1726 return probe->instance_klass();
1727 } else {
1728 // This thread will define the class (even if earlier thread tried and had an error)
1729 probe->set_definer(THREAD);
1730 }
1731 }
1732
1733 define_instance_class(k, THREAD);
1734
1735 Handle linkage_exception = Handle(); // null handle
1736
1737 // definer must notify any waiting threads
1738 {
1739 MutexLocker mu(SystemDictionary_lock, THREAD);
1740 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1741 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1742 if (probe != NULL) {
1743 if (HAS_PENDING_EXCEPTION) {
1744 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1745 CLEAR_PENDING_EXCEPTION;
1746 } else {
1747 probe->set_instance_klass(k);
1748 }
1749 probe->set_definer(NULL);
1750 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1751 SystemDictionary_lock->notify_all();
1752 }
1753 }
1754
1755 // Can't throw exception while holding lock due to rank ordering
1756 if (linkage_exception() != NULL) {
1757 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1758 }
1759
1760 return k;
1761 }
1762
1763 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1764 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1765 if (class_loader.is_null()) {
1766 return Handle(THREAD, _system_loader_lock_obj);
1767 } else {
1768 return class_loader;
1769 }
1770 }
1771
1772 // This method is added to check how often we have to wait to grab loader
1773 // lock. The results are being recorded in the performance counters defined in
1774 // ClassLoader::_sync_systemLoaderLockContentionRate and
1775 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1776 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1777 if (!UsePerfData) {
1778 return;
1779 }
1780
1781 assert(!loader_lock.is_null(), "NULL lock object");
1782
1783 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1784 == ObjectSynchronizer::owner_other) {
1785 // contention will likely happen, so increment the corresponding
1786 // contention counter.
1787 if (oopDesc::equals(loader_lock(), _system_loader_lock_obj)) {
1788 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1789 } else {
1790 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1791 }
1792 }
1793 }
1794
1795 // ----------------------------------------------------------------------------
1796 // Lookup
1797
1798 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1799 Symbol* class_name,
1800 Dictionary* dictionary) {
1801 assert_locked_or_safepoint(SystemDictionary_lock);
1802 int index = dictionary->hash_to_index(hash);
1803 return dictionary->find_class(index, hash, class_name);
1804 }
1805
1806
1807 // Basic find on classes in the midst of being loaded
1808 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1809 ClassLoaderData* loader_data) {
1810 assert_locked_or_safepoint(SystemDictionary_lock);
1811 unsigned int p_hash = placeholders()->compute_hash(class_name);
1812 int p_index = placeholders()->hash_to_index(p_hash);
1813 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1814 }
1815
1816
1817 // Used for assertions and verification only
1818 // Precalculating the hash and index is an optimization because there are many lookups
1819 // before adding the class.
1820 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1821 assert_locked_or_safepoint(SystemDictionary_lock);
1822 #ifndef ASSERT
1823 guarantee(VerifyBeforeGC ||
1824 VerifyDuringGC ||
1825 VerifyBeforeExit ||
1826 VerifyDuringStartup ||
1827 VerifyAfterGC, "too expensive");
1828 #endif
1829
1830 Dictionary* dictionary = loader_data->dictionary();
1831 unsigned int d_hash = dictionary->compute_hash(class_name);
1832 return find_class(d_hash, class_name, dictionary);
1833 }
1834
1835
1836 // ----------------------------------------------------------------------------
1837 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1838 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1839 // before a new class is used.
1840
1841 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1842 assert(k != NULL, "just checking");
1843 assert_locked_or_safepoint(Compile_lock);
1844
1845 k->set_init_state(InstanceKlass::loaded);
1846 // make sure init_state store is already done.
1847 // The compiler reads the hierarchy outside of the Compile_lock.
1848 // Access ordering is used to add to hierarchy.
1849
1850 // Link into hierachy.
1851 k->append_to_sibling_list(); // add to superklass/sibling list
1852 k->process_interfaces(THREAD); // handle all "implements" declarations
1853
1854 // Now flush all code that depended on old class hierarchy.
1855 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1856 CodeCache::flush_dependents_on(k);
1857 }
1858
1859 // ----------------------------------------------------------------------------
1860 // GC support
1861
1862 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1863 // Note: anonymous classes are not in the SD.
1864 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1865
1866 bool unloading_occurred;
1867 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1868 {
1869 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
1870 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
1871 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1872 unloading_occurred = ClassLoaderDataGraph::do_unloading();
1873 if (unloading_occurred) {
1874 MutexLockerEx ml2(is_concurrent ? Module_lock : NULL);
1875 JFR_ONLY(Jfr::on_unloading_classes();)
1876
1877 MutexLockerEx ml1(is_concurrent ? SystemDictionary_lock : NULL);
1878 ClassLoaderDataGraph::clean_module_and_package_info();
1879 constraints()->purge_loader_constraints();
1880 resolution_errors()->purge_resolution_errors();
1881 }
1882 }
1883
1884 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
1885 // Trigger cleaning the ResolvedMethodTable even if no unloading occurred.
1886 ResolvedMethodTable::trigger_cleanup();
1887
1888 if (unloading_occurred) {
1889 SymbolTable::trigger_cleanup();
1890
1891 // Oops referenced by the protection domain cache table may get unreachable independently
1892 // of the class loader (eg. cached protection domain oops). So we need to
1893 // explicitly unlink them here.
1894 // All protection domain oops are linked to the caller class, so if nothing
1895 // unloads, this is not needed.
1896 _pd_cache_table->trigger_cleanup();
1897 }
1898
1899 return unloading_occurred;
1900 }
1901
1902 void SystemDictionary::oops_do(OopClosure* f) {
1903 f->do_oop(&_java_system_loader);
1904 f->do_oop(&_java_platform_loader);
1905 f->do_oop(&_system_loader_lock_obj);
1906 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1907
1908 // Visit extra methods
1909 invoke_method_table()->oops_do(f);
1910 }
1911
1912 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
1913 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
1914 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
1915 it->push(well_known_klass_addr((WKID)id));
1916 }
1917 }
1918
1919 void SystemDictionary::methods_do(void f(Method*)) {
1920 // Walk methods in loaded classes
1921 MutexLocker ml(ClassLoaderDataGraph_lock);
1922 ClassLoaderDataGraph::methods_do(f);
1923 // Walk method handle intrinsics
1924 invoke_method_table()->methods_do(f);
1925 }
1926
1927 // ----------------------------------------------------------------------------
1928 // Initialization
1929
1930 void SystemDictionary::initialize(TRAPS) {
1931 // Allocate arrays
1932 _placeholders = new PlaceholderTable(_placeholder_table_size);
1933 _number_of_modifications = 0;
1934 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1935 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1936 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1937 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
1938
1939 // Allocate private object used as system class loader lock
1940 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1941 // Initialize basic classes
1942 resolve_well_known_classes(CHECK);
1943 }
1944
1945 // Compact table of directions on the initialization of klasses:
1946 static const short wk_init_info[] = {
1947 #define WK_KLASS_INIT_INFO(name, symbol) \
1948 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
1949
1950 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1951 #undef WK_KLASS_INIT_INFO
1952 0
1953 };
1954
1955 #ifdef ASSERT
1956 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
1957 int sid;
1958 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
1959 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1960 if (class_name == symbol) {
1961 return true;
1962 }
1963 }
1964 return false;
1965 }
1966 #endif
1967
1968 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
1969 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1970 int sid = wk_init_info[id - FIRST_WKID];
1971 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1972 InstanceKlass** klassp = &_well_known_klasses[id];
1973
1974
1975 #if INCLUDE_JVMCI
1976 if (id >= FIRST_JVMCI_WKID) {
1977 assert(EnableJVMCI, "resolve JVMCI classes only when EnableJVMCI is true");
1978 }
1979 #endif
1980
1981 if ((*klassp) == NULL) {
1982 Klass* k = resolve_or_fail(symbol, true, CHECK_0);
1983 (*klassp) = InstanceKlass::cast(k);
1984 }
1985 return ((*klassp) != NULL);
1986 }
1987
1988 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1989 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1990 for (int id = (int)start_id; id < (int)limit_id; id++) {
1991 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1992 resolve_wk_klass((WKID)id, CHECK);
1993 }
1994
1995 // move the starting value forward to the limit:
1996 start_id = limit_id;
1997 }
1998
1999 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2000 assert(WK_KLASS(Object_klass) == NULL, "well-known classes should only be initialized once");
2001
2002 // Create the ModuleEntry for java.base. This call needs to be done here,
2003 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2004 ClassLoader::classLoader_init2(CHECK);
2005
2006 // Preload commonly used klasses
2007 WKID scan = FIRST_WKID;
2008 // first do Object, then String, Class
2009 #if INCLUDE_CDS
2010 if (UseSharedSpaces) {
2011 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2012
2013 // It's unsafe to access the archived heap regions before they
2014 // are fixed up, so we must do the fixup as early as possible
2015 // before the archived java objects are accessed by functions
2016 // such as java_lang_Class::restore_archived_mirror and
2017 // ConstantPool::restore_unshareable_info (restores the archived
2018 // resolved_references array object).
2019 //
2020 // HeapShared::fixup_mapped_heap_regions() fills the empty
2021 // spaces in the archived heap regions and may use
2022 // SystemDictionary::Object_klass(), so we can do this only after
2023 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2024 // call. No mirror objects are accessed/restored in the above call.
2025 // Mirrors are restored after java.lang.Class is loaded.
2026 HeapShared::fixup_mapped_heap_regions();
2027
2028 // Initialize the constant pool for the Object_class
2029 assert(Object_klass()->is_shared(), "must be");
2030 Object_klass()->constants()->restore_unshareable_info(CHECK);
2031 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2032 } else
2033 #endif
2034 {
2035 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2036 }
2037
2038 // Calculate offsets for String and Class classes since they are loaded and
2039 // can be used after this point.
2040 java_lang_String::compute_offsets();
2041 java_lang_Class::compute_offsets();
2042
2043 // Fixup mirrors for classes loaded before java.lang.Class.
2044 // These calls iterate over the objects currently in the perm gen
2045 // so calling them at this point is matters (not before when there
2046 // are fewer objects and not later after there are more objects
2047 // in the perm gen.
2048 Universe::initialize_basic_type_mirrors(CHECK);
2049 Universe::fixup_mirrors(CHECK);
2050
2051 // do a bunch more:
2052 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2053
2054 // Preload ref klasses and set reference types
2055 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2056 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2057
2058 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2059 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2060 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2061 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2062 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2063
2064 // JSR 292 classes
2065 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2066 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2067 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2068 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2069 WKID last = NOT_JVMCI(WKID_LIMIT) JVMCI_ONLY(FIRST_JVMCI_WKID);
2070 resolve_wk_klasses_until(last, scan, CHECK);
2071
2072 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2073 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2074 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2075 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2076 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2077 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2078 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2079 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2080 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2081 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2082
2083 { // Compute whether we should use checkPackageAccess or NOT
2084 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2085 _has_checkPackageAccess = (method != NULL);
2086 }
2087
2088 #ifdef ASSERT
2089 if (UseSharedSpaces) {
2090 assert(JvmtiExport::is_early_phase(),
2091 "All well known classes must be resolved in JVMTI early phase");
2092 for (int i = FIRST_WKID; i < last; i++) {
2093 InstanceKlass* k = _well_known_klasses[i];
2094 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2095 }
2096 }
2097 #endif
2098 }
2099
2100 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2101 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2102 BasicType SystemDictionary::box_klass_type(Klass* k) {
2103 assert(k != NULL, "");
2104 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2105 if (_box_klasses[i] == k)
2106 return (BasicType)i;
2107 }
2108 return T_OBJECT;
2109 }
2110
2111 // Constraints on class loaders. The details of the algorithm can be
2112 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2113 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2114 // that the dictionary needs to maintain a set of contraints that
2115 // must be satisfied by all classes in the dictionary.
2116 // if defining is true, then LinkageError if already in dictionary
2117 // if initiating loader, then ok if InstanceKlass matches existing entry
2118
2119 void SystemDictionary::check_constraints(unsigned int d_hash,
2120 InstanceKlass* k,
2121 Handle class_loader,
2122 bool defining,
2123 TRAPS) {
2124 ResourceMark rm(THREAD);
2125 stringStream ss;
2126 bool throwException = false;
2127
2128 {
2129 Symbol *name = k->name();
2130 ClassLoaderData *loader_data = class_loader_data(class_loader);
2131
2132 MutexLocker mu(SystemDictionary_lock, THREAD);
2133
2134 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2135 if (check != NULL) {
2136 // If different InstanceKlass - duplicate class definition,
2137 // else - ok, class loaded by a different thread in parallel.
2138 // We should only have found it if it was done loading and ok to use.
2139 // The dictionary only holds instance classes, placeholders
2140 // also hold array classes.
2141
2142 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2143 if ((defining == true) || (k != check)) {
2144 throwException = true;
2145 ss.print("loader %s", loader_data->loader_name_and_id());
2146 ss.print(" attempted duplicate %s definition for %s. (%s)",
2147 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2148 } else {
2149 return;
2150 }
2151 }
2152
2153 #ifdef ASSERT
2154 Symbol* ph_check = find_placeholder(name, loader_data);
2155 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2156 #endif
2157
2158 if (throwException == false) {
2159 if (constraints()->check_or_update(k, class_loader, name) == false) {
2160 throwException = true;
2161 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2162 ss.print(" wants to load %s %s.",
2163 k->external_kind(), k->external_name());
2164 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2165 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2166 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2167 existing_klass->external_kind(),
2168 existing_klass->class_loader_data()->loader_name_and_id(),
2169 existing_klass->class_in_module_of_loader(false, true));
2170 } else {
2171 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2172 }
2173 }
2174 }
2175 }
2176
2177 // Throw error now if needed (cannot throw while holding
2178 // SystemDictionary_lock because of rank ordering)
2179 if (throwException == true) {
2180 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2181 }
2182 }
2183
2184 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2185 // have been called.
2186 void SystemDictionary::update_dictionary(unsigned int d_hash,
2187 int p_index, unsigned int p_hash,
2188 InstanceKlass* k,
2189 Handle class_loader,
2190 TRAPS) {
2191 // Compile_lock prevents systemDictionary updates during compilations
2192 assert_locked_or_safepoint(Compile_lock);
2193 Symbol* name = k->name();
2194 ClassLoaderData *loader_data = class_loader_data(class_loader);
2195
2196 {
2197 MutexLocker mu1(SystemDictionary_lock, THREAD);
2198
2199 // See whether biased locking is enabled and if so set it for this
2200 // klass.
2201 // Note that this must be done past the last potential blocking
2202 // point / safepoint. We enable biased locking lazily using a
2203 // VM_Operation to iterate the SystemDictionary and installing the
2204 // biasable mark word into each InstanceKlass's prototype header.
2205 // To avoid race conditions where we accidentally miss enabling the
2206 // optimization for one class in the process of being added to the
2207 // dictionary, we must not safepoint after the test of
2208 // BiasedLocking::enabled().
2209 if (UseBiasedLocking && BiasedLocking::enabled()) {
2210 // Set biased locking bit for all loaded classes; it will be
2211 // cleared if revocation occurs too often for this type
2212 // NOTE that we must only do this when the class is initally
2213 // defined, not each time it is referenced from a new class loader
2214 if (oopDesc::equals(k->class_loader(), class_loader()) && !k->is_value()) {
2215 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2216 }
2217 }
2218
2219 // Make a new dictionary entry.
2220 Dictionary* dictionary = loader_data->dictionary();
2221 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2222 if (sd_check == NULL) {
2223 dictionary->add_klass(d_hash, name, k);
2224
2225 notice_modification();
2226 }
2227 #ifdef ASSERT
2228 sd_check = find_class(d_hash, name, dictionary);
2229 assert (sd_check != NULL, "should have entry in dictionary");
2230 // Note: there may be a placeholder entry: for circularity testing
2231 // or for parallel defines
2232 #endif
2233 SystemDictionary_lock->notify_all();
2234 }
2235 }
2236
2237
2238 // Try to find a class name using the loader constraints. The
2239 // loader constraints might know about a class that isn't fully loaded
2240 // yet and these will be ignored.
2241 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2242 Symbol* class_name, Handle class_loader, TRAPS) {
2243
2244 // First see if it has been loaded directly.
2245 // Force the protection domain to be null. (This removes protection checks.)
2246 Handle no_protection_domain;
2247 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2248 no_protection_domain, CHECK_NULL);
2249 if (klass != NULL)
2250 return klass;
2251
2252 // Now look to see if it has been loaded elsewhere, and is subject to
2253 // a loader constraint that would require this loader to return the
2254 // klass that is already loaded.
2255 if (FieldType::is_array(class_name)) {
2256 // For array classes, their Klass*s are not kept in the
2257 // constraint table. The element Klass*s are.
2258 FieldArrayInfo fd;
2259 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2260 if (t != T_OBJECT && t != T_VALUETYPE) {
2261 klass = Universe::typeArrayKlassObj(t);
2262 } else {
2263 MutexLocker mu(SystemDictionary_lock, THREAD);
2264 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2265 }
2266 // If element class already loaded, allocate array klass
2267 if (klass != NULL) {
2268 klass = klass->array_klass_or_null(fd.dimension());
2269 }
2270 } else {
2271 MutexLocker mu(SystemDictionary_lock, THREAD);
2272 // Non-array classes are easy: simply check the constraint table.
2273 klass = constraints()->find_constrained_klass(class_name, class_loader);
2274 }
2275
2276 return klass;
2277 }
2278
2279
2280 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2281 Handle class_loader1,
2282 Handle class_loader2,
2283 Thread* THREAD) {
2284 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2285 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2286
2287 Symbol* constraint_name = NULL;
2288 // Needs to be in same scope as constraint_name in case a Symbol is created and
2289 // assigned to constraint_name.
2290 FieldArrayInfo fd;
2291 if (!FieldType::is_array(class_name)) {
2292 constraint_name = class_name;
2293 } else {
2294 // For array classes, their Klass*s are not kept in the
2295 // constraint table. The element classes are.
2296 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2297 // primitive types always pass
2298 if (t != T_OBJECT) {
2299 return true;
2300 } else {
2301 constraint_name = fd.object_key();
2302 }
2303 }
2304
2305 Dictionary* dictionary1 = loader_data1->dictionary();
2306 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2307
2308 Dictionary* dictionary2 = loader_data2->dictionary();
2309 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2310
2311 {
2312 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2313 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2314 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2315 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2316 klass2, class_loader2);
2317 }
2318 }
2319
2320 // Add entry to resolution error table to record the error when the first
2321 // attempt to resolve a reference to a class has failed.
2322 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2323 Symbol* error, Symbol* message) {
2324 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2325 int index = resolution_errors()->hash_to_index(hash);
2326 {
2327 MutexLocker ml(SystemDictionary_lock, Thread::current());
2328 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2329 }
2330 }
2331
2332 // Delete a resolution error for RedefineClasses for a constant pool is going away
2333 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2334 resolution_errors()->delete_entry(pool);
2335 }
2336
2337 // Lookup resolution error table. Returns error if found, otherwise NULL.
2338 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2339 Symbol** message) {
2340 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2341 int index = resolution_errors()->hash_to_index(hash);
2342 {
2343 MutexLocker ml(SystemDictionary_lock, Thread::current());
2344 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2345 if (entry != NULL) {
2346 *message = entry->message();
2347 return entry->error();
2348 } else {
2349 return NULL;
2350 }
2351 }
2352 }
2353
2354
2355 // Signature constraints ensure that callers and callees agree about
2356 // the meaning of type names in their signatures. This routine is the
2357 // intake for constraints. It collects them from several places:
2358 //
2359 // * LinkResolver::resolve_method (if check_access is true) requires
2360 // that the resolving class (the caller) and the defining class of
2361 // the resolved method (the callee) agree on each type in the
2362 // method's signature.
2363 //
2364 // * LinkResolver::resolve_interface_method performs exactly the same
2365 // checks.
2366 //
2367 // * LinkResolver::resolve_field requires that the constant pool
2368 // attempting to link to a field agree with the field's defining
2369 // class about the type of the field signature.
2370 //
2371 // * klassVtable::initialize_vtable requires that, when a class
2372 // overrides a vtable entry allocated by a superclass, that the
2373 // overriding method (i.e., the callee) agree with the superclass
2374 // on each type in the method's signature.
2375 //
2376 // * klassItable::initialize_itable requires that, when a class fills
2377 // in its itables, for each non-abstract method installed in an
2378 // itable, the method (i.e., the callee) agree with the interface
2379 // on each type in the method's signature.
2380 //
2381 // All those methods have a boolean (check_access, checkconstraints)
2382 // which turns off the checks. This is used from specialized contexts
2383 // such as bootstrapping, dumping, and debugging.
2384 //
2385 // No direct constraint is placed between the class and its
2386 // supertypes. Constraints are only placed along linked relations
2387 // between callers and callees. When a method overrides or implements
2388 // an abstract method in a supertype (superclass or interface), the
2389 // constraints are placed as if the supertype were the caller to the
2390 // overriding method. (This works well, since callers to the
2391 // supertype have already established agreement between themselves and
2392 // the supertype.) As a result of all this, a class can disagree with
2393 // its supertype about the meaning of a type name, as long as that
2394 // class neither calls a relevant method of the supertype, nor is
2395 // called (perhaps via an override) from the supertype.
2396 //
2397 //
2398 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2399 //
2400 // Make sure all class components (including arrays) in the given
2401 // signature will be resolved to the same class in both loaders.
2402 // Returns the name of the type that failed a loader constraint check, or
2403 // NULL if no constraint failed. No exception except OOME is thrown.
2404 // Arrays are not added to the loader constraint table, their elements are.
2405 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2406 Handle loader1, Handle loader2,
2407 bool is_method, TRAPS) {
2408 // Nothing to do if loaders are the same.
2409 if (oopDesc::equals(loader1(), loader2())) {
2410 return NULL;
2411 }
2412
2413 SignatureStream sig_strm(signature, is_method);
2414 while (!sig_strm.is_done()) {
2415 if (sig_strm.is_object()) {
2416 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2417 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2418 return sig;
2419 }
2420 }
2421 sig_strm.next();
2422 }
2423 return NULL;
2424 }
2425
2426
2427 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2428 Symbol* signature,
2429 TRAPS) {
2430 methodHandle empty;
2431 assert(MethodHandles::is_signature_polymorphic(iid) &&
2432 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2433 iid != vmIntrinsics::_invokeGeneric,
2434 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2435
2436 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2437 int index = invoke_method_table()->hash_to_index(hash);
2438 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2439 methodHandle m;
2440 if (spe == NULL || spe->method() == NULL) {
2441 spe = NULL;
2442 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2443 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2444 if (!Arguments::is_interpreter_only()) {
2445 // Generate a compiled form of the MH intrinsic.
2446 AdapterHandlerLibrary::create_native_wrapper(m);
2447 // Check if have the compiled code.
2448 if (!m->has_compiled_code()) {
2449 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2450 "Out of space in CodeCache for method handle intrinsic", empty);
2451 }
2452 }
2453 // Now grab the lock. We might have to throw away the new method,
2454 // if a racing thread has managed to install one at the same time.
2455 {
2456 MutexLocker ml(SystemDictionary_lock, THREAD);
2457 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2458 if (spe == NULL)
2459 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2460 if (spe->method() == NULL)
2461 spe->set_method(m());
2462 }
2463 }
2464
2465 assert(spe != NULL && spe->method() != NULL, "");
2466 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2467 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2468 "MH intrinsic invariant");
2469 return spe->method();
2470 }
2471
2472 // Helper for unpacking the return value from linkMethod and linkCallSite.
2473 static methodHandle unpack_method_and_appendix(Handle mname,
2474 Klass* accessing_klass,
2475 objArrayHandle appendix_box,
2476 Handle* appendix_result,
2477 TRAPS) {
2478 methodHandle empty;
2479 if (mname.not_null()) {
2480 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2481 if (m != NULL) {
2482 oop appendix = appendix_box->obj_at(0);
2483 if (TraceMethodHandles) {
2484 #ifndef PRODUCT
2485 ttyLocker ttyl;
2486 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2487 m->print();
2488 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2489 tty->cr();
2490 #endif //PRODUCT
2491 }
2492 (*appendix_result) = Handle(THREAD, appendix);
2493 // the target is stored in the cpCache and if a reference to this
2494 // MemberName is dropped we need a way to make sure the
2495 // class_loader containing this method is kept alive.
2496 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2497 this_key->record_dependency(m->method_holder());
2498 return methodHandle(THREAD, m);
2499 }
2500 }
2501 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2502 return empty;
2503 }
2504
2505 methodHandle SystemDictionary::find_method_handle_invoker(Klass* klass,
2506 Symbol* name,
2507 Symbol* signature,
2508 Klass* accessing_klass,
2509 Handle *appendix_result,
2510 TRAPS) {
2511 methodHandle empty;
2512 assert(THREAD->can_call_java() ,"");
2513 Handle method_type =
2514 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2515
2516 int ref_kind = JVM_REF_invokeVirtual;
2517 oop name_oop = StringTable::intern(name, CHECK_(empty));
2518 Handle name_str (THREAD, name_oop);
2519 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2520 assert(appendix_box->obj_at(0) == NULL, "");
2521
2522 // This should not happen. JDK code should take care of that.
2523 if (accessing_klass == NULL || method_type.is_null()) {
2524 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2525 }
2526
2527 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2528 JavaCallArguments args;
2529 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2530 args.push_int(ref_kind);
2531 args.push_oop(Handle(THREAD, klass->java_mirror()));
2532 args.push_oop(name_str);
2533 args.push_oop(method_type);
2534 args.push_oop(appendix_box);
2535 JavaValue result(T_OBJECT);
2536 JavaCalls::call_static(&result,
2537 SystemDictionary::MethodHandleNatives_klass(),
2538 vmSymbols::linkMethod_name(),
2539 vmSymbols::linkMethod_signature(),
2540 &args, CHECK_(empty));
2541 Handle mname(THREAD, (oop) result.get_jobject());
2542 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2543 }
2544
2545 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2546 // We must ensure that all class loaders everywhere will reach this class, for any client.
2547 // This is a safe bet for public classes in java.lang, such as Object and String.
2548 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2549 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2550 static bool is_always_visible_class(oop mirror) {
2551 Klass* klass = java_lang_Class::as_Klass(mirror);
2552 if (klass->is_objArray_klass()) {
2553 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2554 }
2555 if (klass->is_typeArray_klass()) {
2556 return true; // primitive array
2557 }
2558 assert(klass->is_instance_klass(), "%s", klass->external_name());
2559 return klass->is_public() &&
2560 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2561 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2562 }
2563
2564
2565 // Return the Java mirror (java.lang.Class instance) for a single-character
2566 // descriptor. This result, when available, is the same as produced by the
2567 // heavier API point of the same name that takes a Symbol.
2568 oop SystemDictionary::find_java_mirror_for_type(char signature_char) {
2569 return java_lang_Class::primitive_mirror(char2type(signature_char));
2570 }
2571
2572 // Find or construct the Java mirror (java.lang.Class instance) for a
2573 // for the given field type signature, as interpreted relative to the
2574 // given class loader. Handles primitives, void, references, arrays,
2575 // and all other reflectable types, except method types.
2576 // N.B. Code in reflection should use this entry point.
2577 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2578 Klass* accessing_klass,
2579 Handle class_loader,
2580 Handle protection_domain,
2581 SignatureStream::FailureMode failure_mode,
2582 TRAPS) {
2583 Handle empty;
2584
2585 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2586 "one or the other, or perhaps neither");
2587
2588 Symbol* type = signature;
2589
2590 // What we have here must be a valid field descriptor,
2591 // and all valid field descriptors are supported.
2592 // Produce the same java.lang.Class that reflection reports.
2593 if (type->utf8_length() == 1) {
2594
2595 // It's a primitive. (Void has a primitive mirror too.)
2596 char ch = type->char_at(0);
2597 assert(is_java_primitive(char2type(ch)) || ch == 'V', "");
2598 return Handle(THREAD, find_java_mirror_for_type(ch));
2599
2600 } else if (FieldType::is_obj(type) || FieldType::is_valuetype(type) || FieldType::is_array(type)) {
2601
2602 // It's a reference type.
2603 if (accessing_klass != NULL) {
2604 class_loader = Handle(THREAD, accessing_klass->class_loader());
2605 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2606 }
2607 Klass* constant_type_klass;
2608 if (failure_mode == SignatureStream::ReturnNull) {
2609 constant_type_klass = resolve_or_null(type, class_loader, protection_domain,
2610 CHECK_(empty));
2611 } else {
2612 bool throw_error = (failure_mode == SignatureStream::NCDFError);
2613 constant_type_klass = resolve_or_fail(type, class_loader, protection_domain,
2614 throw_error, CHECK_(empty));
2615 }
2616 if (constant_type_klass == NULL) {
2617 return Handle(); // report failure this way
2618 }
2619 Handle mirror(THREAD, constant_type_klass->java_mirror());
2620
2621 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2622 if (accessing_klass != NULL) {
2623 Klass* sel_klass = constant_type_klass;
2624 bool fold_type_to_class = true;
2625 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2626 fold_type_to_class, CHECK_(empty));
2627 }
2628
2629 return mirror;
2630
2631 }
2632
2633 // Fall through to an error.
2634 assert(false, "unsupported mirror syntax");
2635 THROW_MSG_(vmSymbols::java_lang_InternalError(), "unsupported mirror syntax", empty);
2636 }
2637
2638
2639 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2640 // signature, as interpreted relative to the given class loader.
2641 // Because of class loader constraints, all method handle usage must be
2642 // consistent with this loader.
2643 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2644 Klass* accessing_klass,
2645 TRAPS) {
2646 Handle empty;
2647 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2648 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2649 int index = invoke_method_table()->hash_to_index(hash);
2650 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2651 if (spe != NULL && spe->method_type() != NULL) {
2652 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2653 return Handle(THREAD, spe->method_type());
2654 } else if (!THREAD->can_call_java()) {
2655 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2656 return Handle(); // do not attempt from within compiler, unless it was cached
2657 }
2658
2659 Handle class_loader, protection_domain;
2660 if (accessing_klass != NULL) {
2661 class_loader = Handle(THREAD, accessing_klass->class_loader());
2662 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2663 }
2664 bool can_be_cached = true;
2665 int npts = ArgumentCount(signature).size();
2666 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2667 int arg = 0;
2668 Handle rt; // the return type from the signature
2669 ResourceMark rm(THREAD);
2670 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2671 oop mirror = NULL;
2672 if (can_be_cached) {
2673 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2674 mirror = ss.as_java_mirror(Handle(), Handle(),
2675 SignatureStream::ReturnNull, CHECK_(empty));
2676 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2677 // Fall back to accessing_klass context.
2678 can_be_cached = false;
2679 }
2680 }
2681 if (!can_be_cached) {
2682 // Resolve, throwing a real error if it doesn't work.
2683 mirror = ss.as_java_mirror(class_loader, protection_domain,
2684 SignatureStream::NCDFError, CHECK_(empty));
2685 }
2686 assert(mirror != NULL, "%s", ss.as_symbol(THREAD)->as_C_string());
2687 if (ss.at_return_type())
2688 rt = Handle(THREAD, mirror);
2689 else
2690 pts->obj_at_put(arg++, mirror);
2691
2692 // Check accessibility.
2693 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2694 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2695 mirror = NULL; // safety
2696 // Emulate ConstantPool::verify_constant_pool_resolve.
2697 bool fold_type_to_class = true;
2698 LinkResolver::check_klass_accessability(accessing_klass, sel_klass,
2699 fold_type_to_class, CHECK_(empty));
2700 }
2701 }
2702 assert(arg == npts, "");
2703
2704 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2705 JavaCallArguments args(Handle(THREAD, rt()));
2706 args.push_oop(pts);
2707 JavaValue result(T_OBJECT);
2708 JavaCalls::call_static(&result,
2709 SystemDictionary::MethodHandleNatives_klass(),
2710 vmSymbols::findMethodHandleType_name(),
2711 vmSymbols::findMethodHandleType_signature(),
2712 &args, CHECK_(empty));
2713 Handle method_type(THREAD, (oop) result.get_jobject());
2714
2715 if (can_be_cached) {
2716 // We can cache this MethodType inside the JVM.
2717 MutexLocker ml(SystemDictionary_lock, THREAD);
2718 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2719 if (spe == NULL)
2720 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2721 if (spe->method_type() == NULL) {
2722 spe->set_method_type(method_type());
2723 }
2724 }
2725
2726 // report back to the caller with the MethodType
2727 return method_type;
2728 }
2729
2730 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2731 Klass* accessing_klass,
2732 TRAPS) {
2733 Handle empty;
2734 ResourceMark rm(THREAD);
2735 SignatureStream ss(signature, /*is_method=*/ false);
2736 if (!ss.is_done()) {
2737 Handle class_loader, protection_domain;
2738 if (accessing_klass != NULL) {
2739 class_loader = Handle(THREAD, accessing_klass->class_loader());
2740 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2741 }
2742 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2743 ss.next();
2744 if (ss.is_done()) {
2745 return Handle(THREAD, mirror);
2746 }
2747 }
2748 return empty;
2749 }
2750
2751 // Ask Java code to find or construct a method handle constant.
2752 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2753 int ref_kind, //e.g., JVM_REF_invokeVirtual
2754 Klass* callee,
2755 Symbol* name,
2756 Symbol* signature,
2757 TRAPS) {
2758 Handle empty;
2759 if (caller == NULL) {
2760 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2761 }
2762 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2763 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2764
2765 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2766 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2767 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2768 java_lang_invoke_MemberName::set_name (mname(), name_str());
2769 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2770 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2771
2772 if (ref_kind == JVM_REF_invokeVirtual &&
2773 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2774 // Skip resolution for public signature polymorphic methods such as
2775 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2776 // They require appendix argument which MemberName resolution doesn't handle.
2777 // There's special logic on JDK side to handle them
2778 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2779 } else {
2780 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2781 }
2782
2783 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2784 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2785
2786 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2787 JavaCallArguments args;
2788 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2789 args.push_int(ref_kind);
2790 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2791 args.push_oop(name_str);
2792 args.push_oop(type);
2793 JavaValue result(T_OBJECT);
2794 JavaCalls::call_static(&result,
2795 SystemDictionary::MethodHandleNatives_klass(),
2796 vmSymbols::linkMethodHandleConstant_name(),
2797 vmSymbols::linkMethodHandleConstant_signature(),
2798 &args, CHECK_(empty));
2799 return Handle(THREAD, (oop) result.get_jobject());
2800 }
2801
2802 // Ask Java to compute a constant by invoking a BSM given a Dynamic_info CP entry
2803 Handle SystemDictionary::link_dynamic_constant(Klass* caller,
2804 int condy_index,
2805 Handle bootstrap_specifier,
2806 Symbol* name,
2807 Symbol* type,
2808 TRAPS) {
2809 Handle empty;
2810 Handle bsm, info;
2811 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2812 bsm = bootstrap_specifier;
2813 } else {
2814 assert(bootstrap_specifier->is_objArray(), "");
2815 objArrayOop args = (objArrayOop) bootstrap_specifier();
2816 assert(args->length() == 2, "");
2817 bsm = Handle(THREAD, args->obj_at(0));
2818 info = Handle(THREAD, args->obj_at(1));
2819 }
2820 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2821 "caller must supply a valid BSM");
2822
2823 // This should not happen. JDK code should take care of that.
2824 if (caller == NULL) {
2825 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad dynamic constant", empty);
2826 }
2827
2828 Handle constant_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2829
2830 // Resolve the constant type in the context of the caller class
2831 Handle type_mirror = find_java_mirror_for_type(type, caller, SignatureStream::NCDFError,
2832 CHECK_(empty));
2833
2834 // call java.lang.invoke.MethodHandleNatives::linkConstantDyanmic(caller, condy_index, bsm, type, info)
2835 JavaCallArguments args;
2836 args.push_oop(Handle(THREAD, caller->java_mirror()));
2837 args.push_int(condy_index);
2838 args.push_oop(bsm);
2839 args.push_oop(constant_name);
2840 args.push_oop(type_mirror);
2841 args.push_oop(info);
2842 JavaValue result(T_OBJECT);
2843 JavaCalls::call_static(&result,
2844 SystemDictionary::MethodHandleNatives_klass(),
2845 vmSymbols::linkDynamicConstant_name(),
2846 vmSymbols::linkDynamicConstant_signature(),
2847 &args, CHECK_(empty));
2848
2849 return Handle(THREAD, (oop) result.get_jobject());
2850 }
2851
2852 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2853 // name and signature, as interpreted relative to the given class loader.
2854 methodHandle SystemDictionary::find_dynamic_call_site_invoker(Klass* caller,
2855 int indy_index,
2856 Handle bootstrap_specifier,
2857 Symbol* name,
2858 Symbol* type,
2859 Handle *appendix_result,
2860 TRAPS) {
2861 methodHandle empty;
2862 Handle bsm, info;
2863 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2864 bsm = bootstrap_specifier;
2865 } else {
2866 objArrayOop args = (objArrayOop) bootstrap_specifier();
2867 assert(args->length() == 2, "");
2868 bsm = Handle(THREAD, args->obj_at(0));
2869 info = Handle(THREAD, args->obj_at(1));
2870 }
2871 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2872 "caller must supply a valid BSM");
2873
2874 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2875 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2876
2877 // This should not happen. JDK code should take care of that.
2878 if (caller == NULL || method_type.is_null()) {
2879 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2880 }
2881
2882 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2883 assert(appendix_box->obj_at(0) == NULL, "");
2884
2885 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2886 JavaCallArguments args;
2887 args.push_oop(Handle(THREAD, caller->java_mirror()));
2888 args.push_int(indy_index);
2889 args.push_oop(bsm);
2890 args.push_oop(method_name);
2891 args.push_oop(method_type);
2892 args.push_oop(info);
2893 args.push_oop(appendix_box);
2894 JavaValue result(T_OBJECT);
2895 JavaCalls::call_static(&result,
2896 SystemDictionary::MethodHandleNatives_klass(),
2897 vmSymbols::linkCallSite_name(),
2898 vmSymbols::linkCallSite_signature(),
2899 &args, CHECK_(empty));
2900 Handle mname(THREAD, (oop) result.get_jobject());
2901 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2902 }
2903
2904 // Protection domain cache table handling
2905
2906 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2907 return _pd_cache_table->get(protection_domain);
2908 }
2909
2910 // ----------------------------------------------------------------------------
2911
2912 void SystemDictionary::print_on(outputStream *st) {
2913 CDS_ONLY(SystemDictionaryShared::print_on(st));
2914 GCMutexLocker mu(SystemDictionary_lock);
2915
2916 ClassLoaderDataGraph::print_dictionary(st);
2917
2918 // Placeholders
2919 placeholders()->print_on(st);
2920 st->cr();
2921
2922 // loader constraints - print under SD_lock
2923 constraints()->print_on(st);
2924 st->cr();
2925
2926 _pd_cache_table->print_on(st);
2927 st->cr();
2928 }
2929
2930 void SystemDictionary::verify() {
2931 guarantee(constraints() != NULL,
2932 "Verify of loader constraints failed");
2933 guarantee(placeholders()->number_of_entries() >= 0,
2934 "Verify of placeholders failed");
2935
2936 GCMutexLocker mu(SystemDictionary_lock);
2937
2938 // Verify dictionary
2939 ClassLoaderDataGraph::verify_dictionary();
2940
2941 placeholders()->verify();
2942
2943 // Verify constraint table
2944 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2945 constraints()->verify(placeholders());
2946
2947 _pd_cache_table->verify();
2948 }
2949
2950 void SystemDictionary::dump(outputStream *st, bool verbose) {
2951 assert_locked_or_safepoint(SystemDictionary_lock);
2952 if (verbose) {
2953 print_on(st);
2954 } else {
2955 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
2956 ClassLoaderDataGraph::print_dictionary_statistics(st);
2957 placeholders()->print_table_statistics(st, "Placeholder Table");
2958 constraints()->print_table_statistics(st, "LoaderConstraints Table");
2959 _pd_cache_table->print_table_statistics(st, "ProtectionDomainCache Table");
2960 }
2961 }
2962
2963 // Utility for dumping dictionaries.
2964 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
2965 DCmdWithParser(output, heap),
2966 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
2967 "BOOLEAN", false, "false") {
2968 _dcmdparser.add_dcmd_option(&_verbose);
2969 }
2970
2971 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
2972 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
2973 _verbose.value());
2974 VMThread::execute(&dumper);
2975 }
2976
2977 int SystemDictionaryDCmd::num_arguments() {
2978 ResourceMark rm;
2979 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
2980 if (dcmd != NULL) {
2981 DCmdMark mark(dcmd);
2982 return dcmd->_dcmdparser.num_arguments();
2983 } else {
2984 return 0;
2985 }
2986 }
2987
2988 void SystemDictionary::initialize_oop_storage() {
2989 _vm_weak_oop_storage =
2990 new OopStorage("VM Weak Oop Handles",
2991 VMWeakAlloc_lock,
2992 VMWeakActive_lock);
2993 }
2994
2995 OopStorage* SystemDictionary::vm_weak_oop_storage() {
2996 assert(_vm_weak_oop_storage != NULL, "Uninitialized");
2997 return _vm_weak_oop_storage;
2998 }