1 /*
2 * Copyright (c) 1997, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "jvm.h"
27 #include "aot/aotLoader.hpp"
28 #include "classfile/classFileParser.hpp"
29 #include "classfile/classFileStream.hpp"
30 #include "classfile/classLoader.hpp"
31 #include "classfile/classLoaderData.inline.hpp"
32 #include "classfile/classLoaderDataGraph.inline.hpp"
33 #include "classfile/classLoaderExt.hpp"
34 #include "classfile/dictionary.hpp"
35 #include "classfile/javaClasses.inline.hpp"
36 #include "classfile/klassFactory.hpp"
37 #include "classfile/loaderConstraints.hpp"
38 #include "classfile/packageEntry.hpp"
39 #include "classfile/placeholders.hpp"
40 #include "classfile/protectionDomainCache.hpp"
41 #include "classfile/resolutionErrors.hpp"
42 #include "classfile/stringTable.hpp"
43 #include "classfile/symbolTable.hpp"
44 #include "classfile/systemDictionary.hpp"
45 #include "classfile/vmSymbols.hpp"
46 #include "code/codeCache.hpp"
47 #include "compiler/compileBroker.hpp"
48 #include "gc/shared/gcTraceTime.inline.hpp"
49 #include "gc/shared/oopStorage.inline.hpp"
50 #include "gc/shared/oopStorageSet.hpp"
51 #include "interpreter/bytecodeStream.hpp"
52 #include "interpreter/interpreter.hpp"
53 #include "jfr/jfrEvents.hpp"
54 #include "logging/log.hpp"
55 #include "logging/logStream.hpp"
56 #include "memory/filemap.hpp"
57 #include "memory/heapShared.hpp"
58 #include "memory/metaspaceClosure.hpp"
59 #include "memory/oopFactory.hpp"
60 #include "memory/resourceArea.hpp"
61 #include "memory/universe.hpp"
62 #include "oops/access.inline.hpp"
63 #include "oops/instanceKlass.hpp"
64 #include "oops/instanceRefKlass.hpp"
65 #include "oops/klass.inline.hpp"
66 #include "oops/method.inline.hpp"
67 #include "oops/methodData.hpp"
68 #include "oops/objArrayKlass.hpp"
69 #include "oops/objArrayOop.inline.hpp"
70 #include "oops/oop.inline.hpp"
71 #include "oops/symbol.hpp"
72 #include "oops/typeArrayKlass.hpp"
73 #include "prims/jvmtiExport.hpp"
74 #include "prims/methodHandles.hpp"
75 #include "runtime/arguments.hpp"
76 #include "runtime/biasedLocking.hpp"
77 #include "runtime/handles.inline.hpp"
78 #include "runtime/java.hpp"
79 #include "runtime/javaCalls.hpp"
80 #include "runtime/mutexLocker.hpp"
81 #include "runtime/sharedRuntime.hpp"
82 #include "runtime/signature.hpp"
83 #include "services/classLoadingService.hpp"
84 #include "services/diagnosticCommand.hpp"
85 #include "services/threadService.hpp"
86 #include "utilities/macros.hpp"
87 #include "utilities/utf8.hpp"
88 #if INCLUDE_CDS
89 #include "classfile/systemDictionaryShared.hpp"
90 #endif
91 #if INCLUDE_JFR
92 #include "jfr/jfr.hpp"
93 #endif
94
95 PlaceholderTable* SystemDictionary::_placeholders = NULL;
96 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
97 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
98 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
99 ProtectionDomainCacheTable* SystemDictionary::_pd_cache_table = NULL;
100
101 oop SystemDictionary::_system_loader_lock_obj = NULL;
102
103 InstanceKlass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
104 = { NULL /*, NULL...*/ };
105
106 InstanceKlass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
107
108 oop SystemDictionary::_java_system_loader = NULL;
109 oop SystemDictionary::_java_platform_loader = NULL;
110
111 // Default ProtectionDomainCacheSize value
112
113 const int defaultProtectionDomainCacheSize = 1009;
114
115 ClassLoadInfo::ClassLoadInfo() {
116 _protection_domain = Handle();
117 _unsafe_anonymous_host = NULL;
118 _cp_patches = NULL;
119 _class_hidden_info._dynamic_nest_host = NULL;
120 _class_hidden_info._class_data = Handle();
121 _is_hidden = false;
122 _is_strong_hidden = false;
123 _can_access_vm_annotations = false;
124 }
125
126 ClassLoadInfo::ClassLoadInfo(Handle protection_domain) {
127 _protection_domain = protection_domain;
128 _unsafe_anonymous_host = NULL;
129 _cp_patches = NULL;
130 _class_hidden_info._dynamic_nest_host = NULL;
131 _class_hidden_info._class_data = Handle();
132 _is_hidden = false;
133 _is_strong_hidden = false;
134 _can_access_vm_annotations = false;
135 }
136
137 ClassLoadInfo::ClassLoadInfo(Handle protection_domain,
138 const InstanceKlass* unsafe_anonymous_host,
139 GrowableArray<Handle>* cp_patches,
140 InstanceKlass* dynamic_nest_host,
141 Handle class_data,
142 bool is_hidden,
143 bool is_strong_hidden,
144 bool can_access_vm_annotations) {
145 _protection_domain = protection_domain;
146 _unsafe_anonymous_host = unsafe_anonymous_host;
147 _cp_patches = cp_patches;
148 _class_hidden_info._dynamic_nest_host = dynamic_nest_host;
149 _class_hidden_info._class_data = class_data;
150 _is_hidden = is_hidden;
151 _is_strong_hidden = is_strong_hidden;
152 _can_access_vm_annotations = can_access_vm_annotations;
153 }
154
155 // ----------------------------------------------------------------------------
156 // Java-level SystemLoader and PlatformLoader
157
158 oop SystemDictionary::java_system_loader() {
159 return _java_system_loader;
160 }
161
162 oop SystemDictionary::java_platform_loader() {
163 return _java_platform_loader;
164 }
165
166 void SystemDictionary::compute_java_loaders(TRAPS) {
167 JavaValue result(T_OBJECT);
168 InstanceKlass* class_loader_klass = SystemDictionary::ClassLoader_klass();
169 JavaCalls::call_static(&result,
170 class_loader_klass,
171 vmSymbols::getSystemClassLoader_name(),
172 vmSymbols::void_classloader_signature(),
173 CHECK);
174
175 _java_system_loader = (oop)result.get_jobject();
176
177 JavaCalls::call_static(&result,
178 class_loader_klass,
179 vmSymbols::getPlatformClassLoader_name(),
180 vmSymbols::void_classloader_signature(),
181 CHECK);
182
183 _java_platform_loader = (oop)result.get_jobject();
184 }
185
186 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, bool create_mirror_cld) {
187 if (create_mirror_cld) {
188 // Add a new class loader data to the graph.
189 return ClassLoaderDataGraph::add(class_loader, true);
190 } else {
191 return (class_loader() == NULL) ? ClassLoaderData::the_null_class_loader_data() :
192 ClassLoaderDataGraph::find_or_create(class_loader);
193 }
194 }
195
196 // ----------------------------------------------------------------------------
197 // Parallel class loading check
198
199 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
200 if (class_loader.is_null()) return true;
201 if (AlwaysLockClassLoader) return false;
202 return java_lang_ClassLoader::parallelCapable(class_loader());
203 }
204 // ----------------------------------------------------------------------------
205 // ParallelDefineClass flag does not apply to bootclass loader
206 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
207 if (class_loader.is_null()) return false;
208 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
209 return true;
210 }
211 return false;
212 }
213
214 // Returns true if the passed class loader is the builtin application class loader
215 // or a custom system class loader. A customer system class loader can be
216 // specified via -Djava.system.class.loader.
217 bool SystemDictionary::is_system_class_loader(oop class_loader) {
218 if (class_loader == NULL) {
219 return false;
220 }
221 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_AppClassLoader_klass() ||
222 class_loader == _java_system_loader);
223 }
224
225 // Returns true if the passed class loader is the platform class loader.
226 bool SystemDictionary::is_platform_class_loader(oop class_loader) {
227 if (class_loader == NULL) {
228 return false;
229 }
230 return (class_loader->klass() == SystemDictionary::jdk_internal_loader_ClassLoaders_PlatformClassLoader_klass());
231 }
232
233 // ----------------------------------------------------------------------------
234 // Resolving of classes
235
236 Symbol* SystemDictionary::class_name_symbol(const char* name, Symbol* exception, TRAPS) {
237 if (name == NULL) {
238 THROW_MSG_0(exception, "No class name given");
239 }
240 if ((int)strlen(name) > Symbol::max_length()) {
241 // It's impossible to create this class; the name cannot fit
242 // into the constant pool.
243 Exceptions::fthrow(THREAD_AND_LOCATION, exception,
244 "Class name exceeds maximum length of %d: %s",
245 Symbol::max_length(),
246 name);
247 return NULL;
248 }
249 // Callers should ensure that the name is never an illegal UTF8 string.
250 assert(UTF8::is_legal_utf8((const unsigned char*)name, (int)strlen(name), false),
251 "Class name is not a valid utf8 string.");
252
253 // Make a new symbol for the class name.
254 return SymbolTable::new_symbol(name);
255 }
256
257 // Forwards to resolve_or_null
258
259 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
260 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
261 if (HAS_PENDING_EXCEPTION || klass == NULL) {
262 // can return a null klass
263 klass = handle_resolution_exception(class_name, throw_error, klass, THREAD);
264 }
265 return klass;
266 }
267
268 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name,
269 bool throw_error,
270 Klass* klass, TRAPS) {
271 if (HAS_PENDING_EXCEPTION) {
272 // If we have a pending exception we forward it to the caller, unless throw_error is true,
273 // in which case we have to check whether the pending exception is a ClassNotFoundException,
274 // and if so convert it to a NoClassDefFoundError
275 // And chain the original ClassNotFoundException
276 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
277 ResourceMark rm(THREAD);
278 assert(klass == NULL, "Should not have result with exception pending");
279 Handle e(THREAD, PENDING_EXCEPTION);
280 CLEAR_PENDING_EXCEPTION;
281 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
282 } else {
283 return NULL;
284 }
285 }
286 // Class not found, throw appropriate error or exception depending on value of throw_error
287 if (klass == NULL) {
288 ResourceMark rm(THREAD);
289 if (throw_error) {
290 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
291 } else {
292 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
293 }
294 }
295 return klass;
296 }
297
298
299 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
300 bool throw_error, TRAPS)
301 {
302 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
303 }
304
305
306 // Forwards to resolve_array_class_or_null or resolve_instance_class_or_null
307
308 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
309 if (Signature::is_array(class_name)) {
310 return resolve_array_class_or_null(class_name, class_loader, protection_domain, THREAD);
311 } else {
312 return resolve_instance_class_or_null_helper(class_name, class_loader, protection_domain, THREAD);
313 }
314 }
315
316 // name may be in the form of "java/lang/Object" or "Ljava/lang/Object;"
317 InstanceKlass* SystemDictionary::resolve_instance_class_or_null_helper(Symbol* class_name,
318 Handle class_loader,
319 Handle protection_domain,
320 TRAPS) {
321 assert(class_name != NULL && !Signature::is_array(class_name), "must be");
322 if (Signature::has_envelope(class_name)) {
323 ResourceMark rm(THREAD);
324 // Ignore wrapping L and ;.
325 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
326 class_name->utf8_length() - 2);
327 return resolve_instance_class_or_null(name, class_loader, protection_domain, THREAD);
328 } else {
329 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, THREAD);
330 }
331 }
332
333 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
334 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
335 }
336
337 // Forwards to resolve_instance_class_or_null
338
339 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
340 Handle class_loader,
341 Handle protection_domain,
342 TRAPS) {
343 assert(Signature::is_array(class_name), "must be array");
344 ResourceMark rm(THREAD);
345 SignatureStream ss(class_name, false);
346 int ndims = ss.skip_array_prefix(); // skip all '['s
347 Klass* k = NULL;
348 BasicType t = ss.type();
349 if (ss.has_envelope()) {
350 Symbol* obj_class = ss.as_symbol();
351 k = SystemDictionary::resolve_instance_class_or_null(obj_class,
352 class_loader,
353 protection_domain,
354 CHECK_NULL);
355 if (k != NULL) {
356 k = k->array_klass(ndims, CHECK_NULL);
357 }
358 } else {
359 k = Universe::typeArrayKlassObj(t);
360 k = TypeArrayKlass::cast(k)->array_klass(ndims, CHECK_NULL);
361 }
362 return k;
363 }
364
365
366 // Must be called for any super-class or super-interface resolution
367 // during class definition to allow class circularity checking
368 // super-interface callers:
369 // parse_interfaces - for defineClass & jvmtiRedefineClasses
370 // super-class callers:
371 // ClassFileParser - for defineClass & jvmtiRedefineClasses
372 // load_shared_class - while loading a class from shared archive
373 // resolve_instance_class_or_null:
374 // via: handle_parallel_super_load
375 // when resolving a class that has an existing placeholder with
376 // a saved superclass [i.e. a defineClass is currently in progress]
377 // if another thread is trying to resolve the class, it must do
378 // super-class checks on its own thread to catch class circularity
379 // This last call is critical in class circularity checking for cases
380 // where classloading is delegated to different threads and the
381 // classloader lock is released.
382 // Take the case: Base->Super->Base
383 // 1. If thread T1 tries to do a defineClass of class Base
384 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
385 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
386 // so it tries to load Super
387 // 3. If we load the class internally, or user classloader uses same thread
388 // loadClassFromxxx or defineClass via parseClassFile Super ...
389 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
390 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
391 // 3.4 calls resolve_super_or_fail Base
392 // 3.5 finds T1,Base -> throws class circularity
393 //OR 4. If T2 tries to resolve Super via defineClass Super ...
394 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
395 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
396 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
397 // 4.4 finds T2, Super -> throws class circularity
398 // Must be called, even if superclass is null, since this is
399 // where the placeholder entry is created which claims this
400 // thread is loading this class/classloader.
401 // Be careful when modifying this code: once you have run
402 // placeholders()->find_and_add(PlaceholderTable::LOAD_SUPER),
403 // you need to find_and_remove it before returning.
404 // So be careful to not exit with a CHECK_ macro betweeen these calls.
405 InstanceKlass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
406 Symbol* super_name,
407 Handle class_loader,
408 Handle protection_domain,
409 bool is_superclass,
410 TRAPS) {
411 assert(!Signature::is_array(super_name), "invalid super class name");
412 #if INCLUDE_CDS
413 if (DumpSharedSpaces) {
414 // Special processing for handling UNREGISTERED shared classes.
415 InstanceKlass* k = SystemDictionaryShared::dump_time_resolve_super_or_fail(child_name,
416 super_name, class_loader, protection_domain, is_superclass, CHECK_NULL);
417 if (k) {
418 return k;
419 }
420 }
421 #endif // INCLUDE_CDS
422
423 // Double-check, if child class is already loaded, just return super-class,interface
424 // Don't add a placedholder if already loaded, i.e. already in appropriate class loader
425 // dictionary.
426 // Make sure there's a placeholder for the *child* before resolving.
427 // Used as a claim that this thread is currently loading superclass/classloader
428 // Used here for ClassCircularity checks and also for heap verification
429 // (every InstanceKlass needs to be in its class loader dictionary or have a placeholder).
430 // Must check ClassCircularity before checking if super class is already loaded.
431 //
432 // We might not already have a placeholder if this child_name was
433 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
434 // the name of the class might not be known until the stream is actually
435 // parsed.
436 // Bugs 4643874, 4715493
437
438 ClassLoaderData* loader_data = class_loader_data(class_loader);
439 Dictionary* dictionary = loader_data->dictionary();
440 unsigned int d_hash = dictionary->compute_hash(child_name);
441 unsigned int p_hash = placeholders()->compute_hash(child_name);
442 int p_index = placeholders()->hash_to_index(p_hash);
443 // can't throw error holding a lock
444 bool child_already_loaded = false;
445 bool throw_circularity_error = false;
446 {
447 MutexLocker mu(THREAD, SystemDictionary_lock);
448 InstanceKlass* childk = find_class(d_hash, child_name, dictionary);
449 InstanceKlass* quicksuperk;
450 // to support // loading: if child done loading, just return superclass
451 // if super_name, & class_loader don't match:
452 // if initial define, SD update will give LinkageError
453 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
454 // so we don't throw an exception here.
455 // see: nsk redefclass014 & java.lang.instrument Instrument032
456 if ((childk != NULL ) && (is_superclass) &&
457 ((quicksuperk = childk->java_super()) != NULL) &&
458 ((quicksuperk->name() == super_name) &&
459 (quicksuperk->class_loader() == class_loader()))) {
460 return quicksuperk;
461 } else {
462 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
463 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
464 throw_circularity_error = true;
465 }
466 }
467 if (!throw_circularity_error) {
468 // Be careful not to exit resolve_super
469 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, super_name, THREAD);
470 }
471 }
472 if (throw_circularity_error) {
473 ResourceMark rm(THREAD);
474 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
475 }
476
477 // java.lang.Object should have been found above
478 assert(super_name != NULL, "null super class for resolving");
479 // Resolve the super class or interface, check results on return
480 InstanceKlass* superk =
481 SystemDictionary::resolve_instance_class_or_null_helper(super_name,
482 class_loader,
483 protection_domain,
484 THREAD);
485
486 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
487 // It is no longer necessary to keep the placeholder table alive until update_dictionary
488 // or error. GC used to walk the placeholder table as strong roots.
489 // The instanceKlass is kept alive because the class loader is on the stack,
490 // which keeps the loader_data alive, as well as all instanceKlasses in
491 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
492 {
493 MutexLocker mu(THREAD, SystemDictionary_lock);
494 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
495 SystemDictionary_lock->notify_all();
496 }
497 if (HAS_PENDING_EXCEPTION || superk == NULL) {
498 // can null superk
499 Klass* k = handle_resolution_exception(super_name, true, superk, THREAD);
500 assert(k == NULL || k == superk, "must be");
501 if (k == NULL) {
502 superk = NULL;
503 }
504 }
505
506 return superk;
507 }
508
509 void SystemDictionary::validate_protection_domain(InstanceKlass* klass,
510 Handle class_loader,
511 Handle protection_domain,
512 TRAPS) {
513 // Now we have to call back to java to check if the initating class has access
514 JavaValue result(T_VOID);
515 LogTarget(Debug, protectiondomain) lt;
516 if (lt.is_enabled()) {
517 ResourceMark rm(THREAD);
518 // Print out trace information
519 LogStream ls(lt);
520 ls.print_cr("Checking package access");
521 if (class_loader() != NULL) {
522 ls.print("class loader: ");
523 class_loader()->print_value_on(&ls);
524 } else {
525 ls.print_cr("class loader: NULL");
526 }
527 if (protection_domain() != NULL) {
528 ls.print(" protection domain: ");
529 protection_domain()->print_value_on(&ls);
530 } else {
531 ls.print_cr(" protection domain: NULL");
532 }
533 ls.print(" loading: "); klass->print_value_on(&ls);
534 ls.cr();
535 }
536
537 // This handle and the class_loader handle passed in keeps this class from
538 // being unloaded through several GC points.
539 // The class_loader handle passed in is the initiating loader.
540 Handle mirror(THREAD, klass->java_mirror());
541
542 InstanceKlass* system_loader = SystemDictionary::ClassLoader_klass();
543 JavaCalls::call_special(&result,
544 class_loader,
545 system_loader,
546 vmSymbols::checkPackageAccess_name(),
547 vmSymbols::class_protectiondomain_signature(),
548 mirror,
549 protection_domain,
550 THREAD);
551
552 if (HAS_PENDING_EXCEPTION) {
553 log_debug(protectiondomain)("DENIED !!!!!!!!!!!!!!!!!!!!!");
554 } else {
555 log_debug(protectiondomain)("granted");
556 }
557
558 if (HAS_PENDING_EXCEPTION) return;
559
560 // If no exception has been thrown, we have validated the protection domain
561 // Insert the protection domain of the initiating class into the set.
562 {
563 ClassLoaderData* loader_data = class_loader_data(class_loader);
564 Dictionary* dictionary = loader_data->dictionary();
565
566 Symbol* kn = klass->name();
567 unsigned int d_hash = dictionary->compute_hash(kn);
568
569 MutexLocker mu(THREAD, SystemDictionary_lock);
570 int d_index = dictionary->hash_to_index(d_hash);
571 dictionary->add_protection_domain(d_index, d_hash, klass,
572 protection_domain, THREAD);
573 }
574 }
575
576 // We only get here if this thread finds that another thread
577 // has already claimed the placeholder token for the current operation,
578 // but that other thread either never owned or gave up the
579 // object lock
580 // Waits on SystemDictionary_lock to indicate placeholder table updated
581 // On return, caller must recheck placeholder table state
582 //
583 // We only get here if
584 // 1) custom classLoader, i.e. not bootstrap classloader
585 // 2) custom classLoader has broken the class loader objectLock
586 // so another thread got here in parallel
587 //
588 // lockObject must be held.
589 // Complicated dance due to lock ordering:
590 // Must first release the classloader object lock to
591 // allow initial definer to complete the class definition
592 // and to avoid deadlock
593 // Reclaim classloader lock object with same original recursion count
594 // Must release SystemDictionary_lock after notify, since
595 // class loader lock must be claimed before SystemDictionary_lock
596 // to prevent deadlocks
597 //
598 // The notify allows applications that did an untimed wait() on
599 // the classloader object lock to not hang.
600 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
601 assert_lock_strong(SystemDictionary_lock);
602
603 bool calledholdinglock
604 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
605 assert(calledholdinglock,"must hold lock for notify");
606 assert((lockObject() != _system_loader_lock_obj && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
607 ObjectSynchronizer::notifyall(lockObject, THREAD);
608 intx recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
609 SystemDictionary_lock->wait();
610 SystemDictionary_lock->unlock();
611 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
612 SystemDictionary_lock->lock();
613 }
614
615 // If the class in is in the placeholder table, class loading is in progress
616 // For cases where the application changes threads to load classes, it
617 // is critical to ClassCircularity detection that we try loading
618 // the superclass on the same thread internally, so we do parallel
619 // super class loading here.
620 // This also is critical in cases where the original thread gets stalled
621 // even in non-circularity situations.
622 // Note: must call resolve_super_or_fail even if null super -
623 // to force placeholder entry creation for this class for circularity detection
624 // Caller must check for pending exception
625 // Returns non-null Klass* if other thread has completed load
626 // and we are done,
627 // If return null Klass* and no pending exception, the caller must load the class
628 InstanceKlass* SystemDictionary::handle_parallel_super_load(
629 Symbol* name, Symbol* superclassname, Handle class_loader,
630 Handle protection_domain, Handle lockObject, TRAPS) {
631
632 ClassLoaderData* loader_data = class_loader_data(class_loader);
633 Dictionary* dictionary = loader_data->dictionary();
634 unsigned int d_hash = dictionary->compute_hash(name);
635 unsigned int p_hash = placeholders()->compute_hash(name);
636 int p_index = placeholders()->hash_to_index(p_hash);
637
638 // superk is not used, resolve_super called for circularity check only
639 // This code is reached in two situations. One if this thread
640 // is loading the same class twice (e.g. ClassCircularity, or
641 // java.lang.instrument).
642 // The second is if another thread started the resolve_super first
643 // and has not yet finished.
644 // In both cases the original caller will clean up the placeholder
645 // entry on error.
646 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
647 superclassname,
648 class_loader,
649 protection_domain,
650 true,
651 CHECK_NULL);
652
653 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
654 // Serial class loaders and bootstrap classloader do wait for superclass loads
655 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
656 MutexLocker mu(THREAD, SystemDictionary_lock);
657 // Check if classloading completed while we were loading superclass or waiting
658 return find_class(d_hash, name, dictionary);
659 }
660
661 // must loop to both handle other placeholder updates
662 // and spurious notifications
663 bool super_load_in_progress = true;
664 PlaceholderEntry* placeholder;
665 while (super_load_in_progress) {
666 MutexLocker mu(THREAD, SystemDictionary_lock);
667 // Check if classloading completed while we were loading superclass or waiting
668 InstanceKlass* check = find_class(d_hash, name, dictionary);
669 if (check != NULL) {
670 // Klass is already loaded, so just return it
671 return check;
672 } else {
673 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
674 if (placeholder && placeholder->super_load_in_progress() ){
675 // We only get here if the application has released the
676 // classloader lock when another thread was in the middle of loading a
677 // superclass/superinterface for this class, and now
678 // this thread is also trying to load this class.
679 // To minimize surprises, the first thread that started to
680 // load a class should be the one to complete the loading
681 // with the classfile it initially expected.
682 // This logic has the current thread wait once it has done
683 // all the superclass/superinterface loading it can, until
684 // the original thread completes the class loading or fails
685 // If it completes we will use the resulting InstanceKlass
686 // which we will find below in the systemDictionary.
687 // We also get here for parallel bootstrap classloader
688 if (class_loader.is_null()) {
689 SystemDictionary_lock->wait();
690 } else {
691 double_lock_wait(lockObject, THREAD);
692 }
693 } else {
694 // If not in SD and not in PH, other thread's load must have failed
695 super_load_in_progress = false;
696 }
697 }
698 }
699 return NULL;
700 }
701
702 static void post_class_load_event(EventClassLoad* event, const InstanceKlass* k, const ClassLoaderData* init_cld) {
703 assert(event != NULL, "invariant");
704 assert(k != NULL, "invariant");
705 assert(event->should_commit(), "invariant");
706 event->set_loadedClass(k);
707 event->set_definingClassLoader(k->class_loader_data());
708 event->set_initiatingClassLoader(init_cld);
709 event->commit();
710 }
711
712
713 // Be careful when modifying this code: once you have run
714 // placeholders()->find_and_add(PlaceholderTable::LOAD_INSTANCE),
715 // you need to find_and_remove it before returning.
716 // So be careful to not exit with a CHECK_ macro betweeen these calls.
717 //
718 // name must be in the form of "java/lang/Object" -- cannot be "Ljava/lang/Object;"
719 InstanceKlass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
720 Handle class_loader,
721 Handle protection_domain,
722 TRAPS) {
723 assert(name != NULL && !Signature::is_array(name) &&
724 !Signature::has_envelope(name), "invalid class name");
725
726 EventClassLoad class_load_start_event;
727
728 HandleMark hm(THREAD);
729
730 // Fix for 4474172; see evaluation for more details
731 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
732 ClassLoaderData* loader_data = register_loader(class_loader);
733 Dictionary* dictionary = loader_data->dictionary();
734 unsigned int d_hash = dictionary->compute_hash(name);
735
736 // Do lookup to see if class already exist and the protection domain
737 // has the right access
738 // This call uses find which checks protection domain already matches
739 // All subsequent calls use find_class, and set has_loaded_class so that
740 // before we return a result we call out to java to check for valid protection domain
741 // to allow returning the Klass* and add it to the pd_set if it is valid
742 {
743 InstanceKlass* probe = dictionary->find(d_hash, name, protection_domain);
744 if (probe != NULL) return probe;
745 }
746
747 // Non-bootstrap class loaders will call out to class loader and
748 // define via jvm/jni_DefineClass which will acquire the
749 // class loader object lock to protect against multiple threads
750 // defining the class in parallel by accident.
751 // This lock must be acquired here so the waiter will find
752 // any successful result in the SystemDictionary and not attempt
753 // the define.
754 // ParallelCapable Classloaders and the bootstrap classloader
755 // do not acquire lock here.
756 bool DoObjectLock = true;
757 if (is_parallelCapable(class_loader)) {
758 DoObjectLock = false;
759 }
760
761 unsigned int p_hash = placeholders()->compute_hash(name);
762 int p_index = placeholders()->hash_to_index(p_hash);
763
764 // Class is not in SystemDictionary so we have to do loading.
765 // Make sure we are synchronized on the class loader before we proceed
766 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
767 check_loader_lock_contention(lockObject, THREAD);
768 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
769
770 // Check again (after locking) if class already exist in SystemDictionary
771 bool class_has_been_loaded = false;
772 bool super_load_in_progress = false;
773 bool havesupername = false;
774 InstanceKlass* k = NULL;
775 PlaceholderEntry* placeholder;
776 Symbol* superclassname = NULL;
777
778 assert(THREAD->can_call_java(),
779 "can not load classes with compiler thread: class=%s, classloader=%s",
780 name->as_C_string(),
781 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string());
782 {
783 MutexLocker mu(THREAD, SystemDictionary_lock);
784 InstanceKlass* check = find_class(d_hash, name, dictionary);
785 if (check != NULL) {
786 // InstanceKlass is already loaded, so just return it
787 class_has_been_loaded = true;
788 k = check;
789 } else {
790 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
791 if (placeholder && placeholder->super_load_in_progress()) {
792 super_load_in_progress = true;
793 if (placeholder->havesupername() == true) {
794 superclassname = placeholder->supername();
795 havesupername = true;
796 }
797 }
798 }
799 }
800
801 // If the class is in the placeholder table, class loading is in progress
802 if (super_load_in_progress && havesupername==true) {
803 k = handle_parallel_super_load(name,
804 superclassname,
805 class_loader,
806 protection_domain,
807 lockObject, THREAD);
808 if (HAS_PENDING_EXCEPTION) {
809 return NULL;
810 }
811 if (k != NULL) {
812 class_has_been_loaded = true;
813 }
814 }
815
816 bool throw_circularity_error = false;
817 if (!class_has_been_loaded) {
818 bool load_instance_added = false;
819
820 // add placeholder entry to record loading instance class
821 // Five cases:
822 // All cases need to prevent modifying bootclasssearchpath
823 // in parallel with a classload of same classname
824 // Redefineclasses uses existence of the placeholder for the duration
825 // of the class load to prevent concurrent redefinition of not completely
826 // defined classes.
827 // case 1. traditional classloaders that rely on the classloader object lock
828 // - no other need for LOAD_INSTANCE
829 // case 2. traditional classloaders that break the classloader object lock
830 // as a deadlock workaround. Detection of this case requires that
831 // this check is done while holding the classloader object lock,
832 // and that lock is still held when calling classloader's loadClass.
833 // For these classloaders, we ensure that the first requestor
834 // completes the load and other requestors wait for completion.
835 // case 3. Bootstrap classloader - don't own objectLocker
836 // This classloader supports parallelism at the classloader level,
837 // but only allows a single load of a class/classloader pair.
838 // No performance benefit and no deadlock issues.
839 // case 4. parallelCapable user level classloaders - without objectLocker
840 // Allow parallel classloading of a class/classloader pair
841
842 {
843 MutexLocker mu(THREAD, SystemDictionary_lock);
844 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
845 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
846 if (oldprobe) {
847 // only need check_seen_thread once, not on each loop
848 // 6341374 java/lang/Instrument with -Xcomp
849 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
850 throw_circularity_error = true;
851 } else {
852 // case 1: traditional: should never see load_in_progress.
853 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
854
855 // case 3: bootstrap classloader: prevent futile classloading,
856 // wait on first requestor
857 if (class_loader.is_null()) {
858 SystemDictionary_lock->wait();
859 } else {
860 // case 2: traditional with broken classloader lock. wait on first
861 // requestor.
862 double_lock_wait(lockObject, THREAD);
863 }
864 // Check if classloading completed while we were waiting
865 InstanceKlass* check = find_class(d_hash, name, dictionary);
866 if (check != NULL) {
867 // Klass is already loaded, so just return it
868 k = check;
869 class_has_been_loaded = true;
870 }
871 // check if other thread failed to load and cleaned up
872 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
873 }
874 }
875 }
876 }
877 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
878 // case 4: parallelCapable: allow competing threads to try
879 // LOAD_INSTANCE in parallel
880
881 if (!throw_circularity_error && !class_has_been_loaded) {
882 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
883 load_instance_added = true;
884 // For class loaders that do not acquire the classloader object lock,
885 // if they did not catch another thread holding LOAD_INSTANCE,
886 // need a check analogous to the acquire ObjectLocker/find_class
887 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
888 // one final check if the load has already completed
889 // class loaders holding the ObjectLock shouldn't find the class here
890 InstanceKlass* check = find_class(d_hash, name, dictionary);
891 if (check != NULL) {
892 // Klass is already loaded, so return it after checking/adding protection domain
893 k = check;
894 class_has_been_loaded = true;
895 }
896 }
897 }
898
899 // must throw error outside of owning lock
900 if (throw_circularity_error) {
901 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
902 ResourceMark rm(THREAD);
903 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
904 }
905
906 if (!class_has_been_loaded) {
907
908 // Do actual loading
909 k = load_instance_class(name, class_loader, THREAD);
910
911 // If everything was OK (no exceptions, no null return value), and
912 // class_loader is NOT the defining loader, do a little more bookkeeping.
913 if (!HAS_PENDING_EXCEPTION && k != NULL &&
914 k->class_loader() != class_loader()) {
915
916 check_constraints(d_hash, k, class_loader, false, THREAD);
917
918 // Need to check for a PENDING_EXCEPTION again; check_constraints
919 // can throw but we may have to remove entry from the placeholder table below.
920 if (!HAS_PENDING_EXCEPTION) {
921 // Record dependency for non-parent delegation.
922 // This recording keeps the defining class loader of the klass (k) found
923 // from being unloaded while the initiating class loader is loaded
924 // even if the reference to the defining class loader is dropped
925 // before references to the initiating class loader.
926 loader_data->record_dependency(k);
927
928 { // Grabbing the Compile_lock prevents systemDictionary updates
929 // during compilations.
930 MutexLocker mu(THREAD, Compile_lock);
931 update_dictionary(d_hash, p_index, p_hash,
932 k, class_loader, THREAD);
933 }
934
935 if (JvmtiExport::should_post_class_load()) {
936 Thread *thread = THREAD;
937 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
938 JvmtiExport::post_class_load((JavaThread *) thread, k);
939 }
940 }
941 }
942 } // load_instance_class
943
944 if (load_instance_added == true) {
945 // clean up placeholder entries for LOAD_INSTANCE success or error
946 // This brackets the SystemDictionary updates for both defining
947 // and initiating loaders
948 MutexLocker mu(THREAD, SystemDictionary_lock);
949 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
950 SystemDictionary_lock->notify_all();
951 }
952 }
953
954 if (HAS_PENDING_EXCEPTION || k == NULL) {
955 return NULL;
956 }
957 if (class_load_start_event.should_commit()) {
958 post_class_load_event(&class_load_start_event, k, loader_data);
959 }
960 #ifdef ASSERT
961 {
962 ClassLoaderData* loader_data = k->class_loader_data();
963 MutexLocker mu(THREAD, SystemDictionary_lock);
964 InstanceKlass* kk = find_class(name, loader_data);
965 assert(kk == k, "should be present in dictionary");
966 }
967 #endif
968
969 // return if the protection domain in NULL
970 if (protection_domain() == NULL) return k;
971
972 // Check the protection domain has the right access
973 if (dictionary->is_valid_protection_domain(d_hash, name,
974 protection_domain)) {
975 return k;
976 }
977
978 // Verify protection domain. If it fails an exception is thrown
979 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
980
981 return k;
982 }
983
984
985 // This routine does not lock the system dictionary.
986 //
987 // Since readers don't hold a lock, we must make sure that system
988 // dictionary entries are only removed at a safepoint (when only one
989 // thread is running), and are added to in a safe way (all links must
990 // be updated in an MT-safe manner).
991 //
992 // Callers should be aware that an entry could be added just after
993 // _dictionary->bucket(index) is read here, so the caller will not see
994 // the new entry.
995
996 Klass* SystemDictionary::find(Symbol* class_name,
997 Handle class_loader,
998 Handle protection_domain,
999 TRAPS) {
1000
1001 // The result of this call should be consistent with the result
1002 // of the call to resolve_instance_class_or_null().
1003 // See evaluation 6790209 and 4474172 for more details.
1004 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
1005 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
1006
1007 if (loader_data == NULL) {
1008 // If the ClassLoaderData has not been setup,
1009 // then the class loader has no entries in the dictionary.
1010 return NULL;
1011 }
1012
1013 Dictionary* dictionary = loader_data->dictionary();
1014 unsigned int d_hash = dictionary->compute_hash(class_name);
1015 return dictionary->find(d_hash, class_name,
1016 protection_domain);
1017 }
1018
1019
1020 // Look for a loaded instance or array klass by name. Do not do any loading.
1021 // return NULL in case of error.
1022 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
1023 Handle class_loader,
1024 Handle protection_domain,
1025 TRAPS) {
1026 Klass* k = NULL;
1027 assert(class_name != NULL, "class name must be non NULL");
1028
1029 if (Signature::is_array(class_name)) {
1030 // The name refers to an array. Parse the name.
1031 // dimension and object_key in FieldArrayInfo are assigned as a
1032 // side-effect of this call
1033 SignatureStream ss(class_name, false);
1034 int ndims = ss.skip_array_prefix(); // skip all '['s
1035 BasicType t = ss.type();
1036 if (t != T_OBJECT) {
1037 k = Universe::typeArrayKlassObj(t);
1038 } else {
1039 k = SystemDictionary::find(ss.as_symbol(), class_loader, protection_domain, THREAD);
1040 }
1041 if (k != NULL) {
1042 k = k->array_klass_or_null(ndims);
1043 }
1044 } else {
1045 k = find(class_name, class_loader, protection_domain, THREAD);
1046 }
1047 return k;
1048 }
1049
1050 // Note: this method is much like resolve_from_stream, but
1051 // does not publish the classes via the SystemDictionary.
1052 // Handles Lookup.defineClass hidden, unsafe_DefineAnonymousClass
1053 // and redefineclasses. RedefinedClasses do not add to the class hierarchy.
1054 InstanceKlass* SystemDictionary::parse_stream(Symbol* class_name,
1055 Handle class_loader,
1056 ClassFileStream* st,
1057 const ClassLoadInfo& cl_info,
1058 TRAPS) {
1059
1060 EventClassLoad class_load_start_event;
1061 ClassLoaderData* loader_data;
1062 bool is_unsafe_anon_class = cl_info.unsafe_anonymous_host() != NULL;
1063
1064 // - for unsafe anonymous class: create a new CLD whith a class holder that uses
1065 // the same class loader as the unsafe_anonymous_host.
1066 // - for hidden classes that are not strong: create a new CLD that has a class holder and
1067 // whose loader is the Lookup class's loader.
1068 // - for hidden class: add the class to the Lookup class's loader's CLD.
1069 if (is_unsafe_anon_class || cl_info.is_hidden()) {
1070 guarantee(!is_unsafe_anon_class || cl_info.unsafe_anonymous_host()->class_loader() == class_loader(),
1071 "should be NULL or the same");
1072 bool create_mirror_cld = is_unsafe_anon_class || !cl_info.is_strong_hidden();
1073 loader_data = register_loader(class_loader, create_mirror_cld);
1074 } else {
1075 loader_data = ClassLoaderData::class_loader_data(class_loader());
1076 }
1077
1078 assert(st != NULL, "invariant");
1079 assert(st->need_verify(), "invariant");
1080
1081 // Parse stream and create a klass.
1082 // Note that we do this even though this klass might
1083 // already be present in the SystemDictionary, otherwise we would not
1084 // throw potential ClassFormatErrors.
1085
1086 InstanceKlass* k = KlassFactory::create_from_stream(st,
1087 class_name,
1088 loader_data,
1089 cl_info,
1090 CHECK_NULL);
1091
1092 if ((cl_info.is_hidden() || is_unsafe_anon_class) && k != NULL) {
1093 // Hidden classes that are not strong and unsafe anonymous classes must update
1094 // ClassLoaderData holder so that they can be unloaded when the mirror is no
1095 // longer referenced.
1096 if (!cl_info.is_strong_hidden() || is_unsafe_anon_class) {
1097 k->class_loader_data()->initialize_holder(Handle(THREAD, k->java_mirror()));
1098 }
1099
1100 {
1101 MutexLocker mu_r(THREAD, Compile_lock);
1102
1103 // Add to class hierarchy, initialize vtables, and do possible
1104 // deoptimizations.
1105 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1106 // But, do not add to dictionary.
1107 }
1108
1109 // Rewrite and patch constant pool here.
1110 k->link_class(CHECK_NULL);
1111 if (cl_info.cp_patches() != NULL) {
1112 k->constants()->patch_resolved_references(cl_info.cp_patches());
1113 }
1114
1115 // If it's anonymous, initialize it now, since nobody else will.
1116 if (is_unsafe_anon_class) {
1117 k->eager_initialize(CHECK_NULL);
1118 }
1119
1120 // notify jvmti
1121 if (JvmtiExport::should_post_class_load()) {
1122 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1123 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1124 }
1125 if (class_load_start_event.should_commit()) {
1126 post_class_load_event(&class_load_start_event, k, loader_data);
1127 }
1128 }
1129 assert(is_unsafe_anon_class || NULL == cl_info.cp_patches(),
1130 "cp_patches only found with unsafe_anonymous_host");
1131
1132 return k;
1133 }
1134
1135 // Add a klass to the system from a stream (called by jni_DefineClass and
1136 // JVM_DefineClass).
1137 // Note: class_name can be NULL. In that case we do not know the name of
1138 // the class until we have parsed the stream.
1139
1140 InstanceKlass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1141 Handle class_loader,
1142 Handle protection_domain,
1143 ClassFileStream* st,
1144 TRAPS) {
1145
1146 HandleMark hm(THREAD);
1147
1148 // Classloaders that support parallelism, e.g. bootstrap classloader,
1149 // do not acquire lock here
1150 bool DoObjectLock = true;
1151 if (is_parallelCapable(class_loader)) {
1152 DoObjectLock = false;
1153 }
1154
1155 ClassLoaderData* loader_data = register_loader(class_loader);
1156
1157 // Make sure we are synchronized on the class loader before we proceed
1158 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1159 check_loader_lock_contention(lockObject, THREAD);
1160 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1161
1162 assert(st != NULL, "invariant");
1163
1164 // Parse the stream and create a klass.
1165 // Note that we do this even though this klass might
1166 // already be present in the SystemDictionary, otherwise we would not
1167 // throw potential ClassFormatErrors.
1168 InstanceKlass* k = NULL;
1169
1170 #if INCLUDE_CDS
1171 if (!DumpSharedSpaces) {
1172 k = SystemDictionaryShared::lookup_from_stream(class_name,
1173 class_loader,
1174 protection_domain,
1175 st,
1176 CHECK_NULL);
1177 }
1178 #endif
1179
1180 if (k == NULL) {
1181 if (st->buffer() == NULL) {
1182 return NULL;
1183 }
1184 ClassLoadInfo cl_info(protection_domain);
1185 k = KlassFactory::create_from_stream(st, class_name, loader_data, cl_info, CHECK_NULL);
1186 }
1187
1188 assert(k != NULL, "no klass created");
1189 Symbol* h_name = k->name();
1190 assert(class_name == NULL || class_name == h_name, "name mismatch");
1191
1192 // Add class just loaded
1193 // If a class loader supports parallel classloading handle parallel define requests
1194 // find_or_define_instance_class may return a different InstanceKlass
1195 if (is_parallelCapable(class_loader)) {
1196 InstanceKlass* defined_k = find_or_define_instance_class(h_name, class_loader, k, THREAD);
1197 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1198 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1199 assert(defined_k != NULL, "Should have a klass if there's no exception");
1200 loader_data->add_to_deallocate_list(k);
1201 k = defined_k;
1202 }
1203 } else {
1204 define_instance_class(k, THREAD);
1205 }
1206
1207 // If defining the class throws an exception register 'k' for cleanup.
1208 if (HAS_PENDING_EXCEPTION) {
1209 assert(k != NULL, "Must have an instance klass here!");
1210 loader_data->add_to_deallocate_list(k);
1211 return NULL;
1212 }
1213
1214 // Make sure we have an entry in the SystemDictionary on success
1215 debug_only( {
1216 MutexLocker mu(THREAD, SystemDictionary_lock);
1217
1218 Klass* check = find_class(h_name, k->class_loader_data());
1219 assert(check == k, "should be present in the dictionary");
1220 } );
1221
1222 return k;
1223 }
1224
1225 #if INCLUDE_CDS
1226 // Load a class for boot loader from the shared spaces. This also
1227 // forces the super class and all interfaces to be loaded.
1228 InstanceKlass* SystemDictionary::load_shared_boot_class(Symbol* class_name,
1229 PackageEntry* pkg_entry,
1230 TRAPS) {
1231 InstanceKlass* ik = SystemDictionaryShared::find_builtin_class(class_name);
1232 if (ik != NULL && ik->is_shared_boot_class()) {
1233 return load_shared_class(ik, Handle(), Handle(), NULL, pkg_entry, THREAD);
1234 }
1235 return NULL;
1236 }
1237
1238 // Check if a shared class can be loaded by the specific classloader:
1239 //
1240 // NULL classloader:
1241 // - Module class from "modules" jimage. ModuleEntry must be defined in the classloader.
1242 // - Class from -Xbootclasspath/a. The class has no defined PackageEntry, or must
1243 // be defined in an unnamed module.
1244 bool SystemDictionary::is_shared_class_visible(Symbol* class_name,
1245 InstanceKlass* ik,
1246 PackageEntry* pkg_entry,
1247 Handle class_loader, TRAPS) {
1248 assert(!ModuleEntryTable::javabase_moduleEntry()->is_patched(),
1249 "Cannot use sharing if java.base is patched");
1250 ResourceMark rm(THREAD);
1251 int path_index = ik->shared_classpath_index();
1252 ClassLoaderData* loader_data = class_loader_data(class_loader);
1253 if (path_index < 0) {
1254 // path_index < 0 indicates that
1255 // 1) the class is intended for a custom loader and should not be loaded by boot/platform/app loaders
1256 // or
1257 // 2) the class is a hidden lambda proxy class which would be loaded by boot/platform/app loaders
1258 if (loader_data->is_builtin_class_loader_data()) {
1259 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1260 return false;
1261 } else {
1262 return true;
1263 }
1264 } else {
1265 return true;
1266 }
1267 }
1268 SharedClassPathEntry* ent =
1269 (SharedClassPathEntry*)FileMapInfo::shared_path(path_index);
1270 if (!Universe::is_module_initialized()) {
1271 assert(ent != NULL && ent->is_modules_image(),
1272 "Loading non-bootstrap classes before the module system is initialized");
1273 assert(class_loader.is_null(), "sanity");
1274 return true;
1275 }
1276 // Get the pkg_entry from the classloader
1277 ModuleEntry* mod_entry = NULL;
1278 TempNewSymbol pkg_name = pkg_entry != NULL ? pkg_entry->name() :
1279 ClassLoader::package_from_class_name(class_name);
1280 if (pkg_name != NULL) {
1281 if (loader_data != NULL) {
1282 if (pkg_entry != NULL) {
1283 mod_entry = pkg_entry->module();
1284 // If the archived class is from a module that has been patched at runtime,
1285 // the class cannot be loaded from the archive.
1286 if (mod_entry != NULL && mod_entry->is_patched()) {
1287 return false;
1288 }
1289 }
1290 }
1291 }
1292
1293 if (class_loader.is_null()) {
1294 assert(ent != NULL, "Shared class for NULL classloader must have valid SharedClassPathEntry");
1295 // The NULL classloader can load archived class originated from the
1296 // "modules" jimage and the -Xbootclasspath/a. For class from the
1297 // "modules" jimage, the PackageEntry/ModuleEntry must be defined
1298 // by the NULL classloader.
1299 if (mod_entry != NULL) {
1300 // PackageEntry/ModuleEntry is found in the classloader. Check if the
1301 // ModuleEntry's location agrees with the archived class' origination.
1302 if (ent->is_modules_image() && mod_entry->location()->starts_with("jrt:")) {
1303 return true; // Module class from the "module" jimage
1304 }
1305 }
1306
1307 // If the archived class is not from the "module" jimage, the class can be
1308 // loaded by the NULL classloader if
1309 //
1310 // 1. the class is from the unamed package
1311 // 2. or, the class is not from a module defined in the NULL classloader
1312 // 3. or, the class is from an unamed module
1313 if (!ent->is_modules_image() && ik->is_shared_boot_class()) {
1314 // the class is from the -Xbootclasspath/a
1315 if (pkg_name == NULL ||
1316 pkg_entry == NULL ||
1317 pkg_entry->in_unnamed_module()) {
1318 assert(mod_entry == NULL ||
1319 mod_entry == loader_data->unnamed_module(),
1320 "the unnamed module is not defined in the classloader");
1321 return true;
1322 }
1323 }
1324 return false;
1325 } else {
1326 bool res = SystemDictionaryShared::is_shared_class_visible_for_classloader(
1327 ik, class_loader, pkg_name, pkg_entry, mod_entry, CHECK_(false));
1328 return res;
1329 }
1330 }
1331
1332 bool SystemDictionary::check_shared_class_super_type(InstanceKlass* child, InstanceKlass* super_type,
1333 Handle class_loader, Handle protection_domain,
1334 bool is_superclass, TRAPS) {
1335 assert(super_type->is_shared(), "must be");
1336
1337 Klass *found = resolve_super_or_fail(child->name(), super_type->name(),
1338 class_loader, protection_domain, is_superclass, CHECK_0);
1339 if (found == super_type) {
1340 return true;
1341 } else {
1342 // The dynamically resolved super type is not the same as the one we used during dump time,
1343 // so we cannot use the child class.
1344 return false;
1345 }
1346 }
1347
1348 bool SystemDictionary::check_shared_class_super_types(InstanceKlass* ik, Handle class_loader,
1349 Handle protection_domain, TRAPS) {
1350 // Check the superclass and interfaces. They must be the same
1351 // as in dump time, because the layout of <ik> depends on
1352 // the specific layout of ik->super() and ik->local_interfaces().
1353 //
1354 // If unexpected superclass or interfaces are found, we cannot
1355 // load <ik> from the shared archive.
1356
1357 if (ik->super() != NULL &&
1358 !check_shared_class_super_type(ik, InstanceKlass::cast(ik->super()),
1359 class_loader, protection_domain, true, THREAD)) {
1360 return false;
1361 }
1362
1363 Array<InstanceKlass*>* interfaces = ik->local_interfaces();
1364 int num_interfaces = interfaces->length();
1365 for (int index = 0; index < num_interfaces; index++) {
1366 if (!check_shared_class_super_type(ik, interfaces->at(index), class_loader, protection_domain, false, THREAD)) {
1367 return false;
1368 }
1369 }
1370
1371 return true;
1372 }
1373
1374 InstanceKlass* SystemDictionary::load_shared_lambda_proxy_class(InstanceKlass* ik,
1375 Handle class_loader,
1376 Handle protection_domain,
1377 PackageEntry* pkg_entry,
1378 bool initialize,
1379 TRAPS) {
1380 InstanceKlass* shared_nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1381 assert(shared_nest_host->is_shared(), "nest host must be in CDS archive");
1382 Symbol* cn = shared_nest_host->name();
1383 Klass *s = resolve_or_fail(cn, class_loader, protection_domain, true, CHECK_NULL);
1384 if (s != shared_nest_host) {
1385 // The dynamically resolved nest_host is not the same as the one we used during dump time,
1386 // so we cannot use ik.
1387 return NULL;
1388 } else {
1389 assert(s->is_shared(), "must be");
1390 }
1391
1392 // The lambda proxy class and its nest host have the same class loader and class loader data,
1393 // as verified in SystemDictionaryShared::add_lambda_proxy_class()
1394 assert(shared_nest_host->class_loader() == class_loader(), "mismatched class loader");
1395 assert(shared_nest_host->class_loader_data() == ClassLoaderData::class_loader_data(class_loader()), "mismatched class loader data");
1396 ik->set_nest_host(shared_nest_host, THREAD);
1397
1398 InstanceKlass* loaded_ik = load_shared_class(ik, class_loader, protection_domain, NULL, pkg_entry, CHECK_NULL);
1399
1400 assert(shared_nest_host->is_same_class_package(ik),
1401 "lambda proxy class and its nest host must be in the same package");
1402
1403 EventClassLoad class_load_start_event;
1404 {
1405 MutexLocker mu_r(THREAD, Compile_lock);
1406
1407 // Add to class hierarchy, initialize vtables, and do possible
1408 // deoptimizations.
1409 SystemDictionary::add_to_hierarchy(loaded_ik, CHECK_NULL); // No exception, but can block
1410 // But, do not add to dictionary.
1411 }
1412 loaded_ik->link_class(CHECK_NULL);
1413 // notify jvmti
1414 if (JvmtiExport::should_post_class_load()) {
1415 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1416 JvmtiExport::post_class_load((JavaThread *) THREAD, loaded_ik);
1417 }
1418 if (class_load_start_event.should_commit()) {
1419 post_class_load_event(&class_load_start_event, loaded_ik, ClassLoaderData::class_loader_data(class_loader()));
1420 }
1421
1422 if (initialize) {
1423 loaded_ik->initialize(CHECK_NULL);
1424 }
1425 return loaded_ik;
1426 }
1427
1428 InstanceKlass* SystemDictionary::load_shared_class(InstanceKlass* ik,
1429 Handle class_loader,
1430 Handle protection_domain,
1431 const ClassFileStream *cfs,
1432 PackageEntry* pkg_entry,
1433 TRAPS) {
1434 assert(ik != NULL, "sanity");
1435 assert(!ik->is_unshareable_info_restored(), "shared class can be loaded only once");
1436 Symbol* class_name = ik->name();
1437
1438 bool visible = is_shared_class_visible(
1439 class_name, ik, pkg_entry, class_loader, CHECK_NULL);
1440 if (!visible) {
1441 return NULL;
1442 }
1443
1444 if (!check_shared_class_super_types(ik, class_loader, protection_domain, THREAD)) {
1445 return NULL;
1446 }
1447
1448 InstanceKlass* new_ik = NULL;
1449 if (!SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1450 new_ik = KlassFactory::check_shared_class_file_load_hook(
1451 ik, class_name, class_loader, protection_domain, cfs, CHECK_NULL);
1452 }
1453 if (new_ik != NULL) {
1454 // The class is changed by CFLH. Return the new class. The shared class is
1455 // not used.
1456 return new_ik;
1457 }
1458
1459 // Adjust methods to recover missing data. They need addresses for
1460 // interpreter entry points and their default native method address
1461 // must be reset.
1462
1463 // Updating methods must be done under a lock so multiple
1464 // threads don't update these in parallel
1465 //
1466 // Shared classes are all currently loaded by either the bootstrap or
1467 // internal parallel class loaders, so this will never cause a deadlock
1468 // on a custom class loader lock.
1469
1470 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1471 {
1472 HandleMark hm(THREAD);
1473 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1474 check_loader_lock_contention(lockObject, THREAD);
1475 ObjectLocker ol(lockObject, THREAD, true);
1476 // prohibited package check assumes all classes loaded from archive call
1477 // restore_unshareable_info which calls ik->set_package()
1478 ik->restore_unshareable_info(loader_data, protection_domain, pkg_entry, CHECK_NULL);
1479 }
1480
1481 load_shared_class_misc(ik, loader_data, CHECK_NULL);
1482 return ik;
1483 }
1484
1485 void SystemDictionary::load_shared_class_misc(InstanceKlass* ik, ClassLoaderData* loader_data, TRAPS) {
1486 ik->print_class_load_logging(loader_data, NULL, NULL);
1487
1488 // For boot loader, ensure that GetSystemPackage knows that a class in this
1489 // package was loaded.
1490 if (loader_data->is_the_null_class_loader_data()) {
1491 int path_index = ik->shared_classpath_index();
1492 if (path_index < 0) {
1493 if (SystemDictionaryShared::is_hidden_lambda_proxy(ik)) {
1494 InstanceKlass* nest_host = SystemDictionaryShared::get_shared_nest_host(ik);
1495 path_index = nest_host->shared_classpath_index();
1496 }
1497 }
1498 ik->set_classpath_index(path_index, THREAD);
1499 }
1500
1501 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1502 // Only dump the classes that can be stored into CDS archive
1503 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1504 ResourceMark rm(THREAD);
1505 classlist_file->print_cr("%s", ik->name()->as_C_string());
1506 classlist_file->flush();
1507 }
1508 }
1509
1510 // notify a class loaded from shared object
1511 ClassLoadingService::notify_class_loaded(ik, true /* shared class */);
1512
1513 ik->set_has_passed_fingerprint_check(false);
1514 if (UseAOT && ik->supers_have_passed_fingerprint_checks()) {
1515 uint64_t aot_fp = AOTLoader::get_saved_fingerprint(ik);
1516 uint64_t cds_fp = ik->get_stored_fingerprint();
1517 if (aot_fp != 0 && aot_fp == cds_fp) {
1518 // This class matches with a class saved in an AOT library
1519 ik->set_has_passed_fingerprint_check(true);
1520 } else {
1521 if (log_is_enabled(Info, class, fingerprint)) {
1522 ResourceMark rm(THREAD);
1523 log_info(class, fingerprint)("%s : expected = " PTR64_FORMAT " actual = " PTR64_FORMAT, ik->external_name(), aot_fp, cds_fp);
1524 }
1525 }
1526 }
1527 }
1528
1529 void SystemDictionary::quick_resolve(InstanceKlass* klass, ClassLoaderData* loader_data, Handle domain, TRAPS) {
1530 assert(!Universe::is_fully_initialized(), "We can make short cuts only during VM initialization");
1531 assert(klass->is_shared(), "Must be shared class");
1532 if (klass->class_loader_data() != NULL) {
1533 return;
1534 }
1535
1536 // add super and interfaces first
1537 Klass* super = klass->super();
1538 if (super != NULL && super->class_loader_data() == NULL) {
1539 assert(super->is_instance_klass(), "Super should be instance klass");
1540 quick_resolve(InstanceKlass::cast(super), loader_data, domain, CHECK);
1541 }
1542
1543 Array<InstanceKlass*>* ifs = klass->local_interfaces();
1544 for (int i = 0; i < ifs->length(); i++) {
1545 InstanceKlass* ik = ifs->at(i);
1546 if (ik->class_loader_data() == NULL) {
1547 quick_resolve(ik, loader_data, domain, CHECK);
1548 }
1549 }
1550
1551 klass->restore_unshareable_info(loader_data, domain, NULL, THREAD);
1552 load_shared_class_misc(klass, loader_data, CHECK);
1553 Dictionary* dictionary = loader_data->dictionary();
1554 unsigned int hash = dictionary->compute_hash(klass->name());
1555 dictionary->add_klass(hash, klass->name(), klass);
1556 add_to_hierarchy(klass, CHECK);
1557 assert(klass->is_loaded(), "Must be in at least loaded state");
1558 }
1559 #endif // INCLUDE_CDS
1560
1561 InstanceKlass* SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1562
1563 if (class_loader.is_null()) {
1564 ResourceMark rm(THREAD);
1565 PackageEntry* pkg_entry = NULL;
1566 bool search_only_bootloader_append = false;
1567 ClassLoaderData *loader_data = class_loader_data(class_loader);
1568
1569 // Find the package in the boot loader's package entry table.
1570 TempNewSymbol pkg_name = ClassLoader::package_from_class_name(class_name);
1571 if (pkg_name != NULL) {
1572 pkg_entry = loader_data->packages()->lookup_only(pkg_name);
1573 }
1574
1575 // Prior to attempting to load the class, enforce the boot loader's
1576 // visibility boundaries.
1577 if (!Universe::is_module_initialized()) {
1578 // During bootstrapping, prior to module initialization, any
1579 // class attempting to be loaded must be checked against the
1580 // java.base packages in the boot loader's PackageEntryTable.
1581 // No class outside of java.base is allowed to be loaded during
1582 // this bootstrapping window.
1583 if (pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1584 // Class is either in the unnamed package or in
1585 // a named package within the unnamed module. Either
1586 // case is outside of java.base, do not attempt to
1587 // load the class post java.base definition. If
1588 // java.base has not been defined, let the class load
1589 // and its package will be checked later by
1590 // ModuleEntryTable::verify_javabase_packages.
1591 if (ModuleEntryTable::javabase_defined()) {
1592 return NULL;
1593 }
1594 } else {
1595 // Check that the class' package is defined within java.base.
1596 ModuleEntry* mod_entry = pkg_entry->module();
1597 Symbol* mod_entry_name = mod_entry->name();
1598 if (mod_entry_name->fast_compare(vmSymbols::java_base()) != 0) {
1599 return NULL;
1600 }
1601 }
1602 } else {
1603 // After the module system has been initialized, check if the class'
1604 // package is in a module defined to the boot loader.
1605 if (pkg_name == NULL || pkg_entry == NULL || pkg_entry->in_unnamed_module()) {
1606 // Class is either in the unnamed package, in a named package
1607 // within a module not defined to the boot loader or in a
1608 // a named package within the unnamed module. In all cases,
1609 // limit visibility to search for the class only in the boot
1610 // loader's append path.
1611 if (!ClassLoader::has_bootclasspath_append()) {
1612 // If there is no bootclasspath append entry, no need to continue
1613 // searching.
1614 return NULL;
1615 }
1616 search_only_bootloader_append = true;
1617 }
1618 }
1619
1620 // Prior to bootstrapping's module initialization, never load a class outside
1621 // of the boot loader's module path
1622 assert(Universe::is_module_initialized() ||
1623 !search_only_bootloader_append,
1624 "Attempt to load a class outside of boot loader's module path");
1625
1626 // Search for classes in the CDS archive.
1627 InstanceKlass* k = NULL;
1628 {
1629 #if INCLUDE_CDS
1630 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1631 k = load_shared_boot_class(class_name, pkg_entry, THREAD);
1632 #endif
1633 }
1634
1635 if (k == NULL) {
1636 // Use VM class loader
1637 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1638 k = ClassLoader::load_class(class_name, search_only_bootloader_append, CHECK_NULL);
1639 }
1640
1641 // find_or_define_instance_class may return a different InstanceKlass
1642 if (k != NULL) {
1643 InstanceKlass* defined_k =
1644 find_or_define_instance_class(class_name, class_loader, k, THREAD);
1645 if (!HAS_PENDING_EXCEPTION && defined_k != k) {
1646 // If a parallel capable class loader already defined this class, register 'k' for cleanup.
1647 assert(defined_k != NULL, "Should have a klass if there's no exception");
1648 loader_data->add_to_deallocate_list(k);
1649 k = defined_k;
1650 } else if (HAS_PENDING_EXCEPTION) {
1651 loader_data->add_to_deallocate_list(k);
1652 return NULL;
1653 }
1654 }
1655 return k;
1656 } else {
1657 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1658 ResourceMark rm(THREAD);
1659
1660 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1661 JavaThread* jt = (JavaThread*) THREAD;
1662
1663 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1664 ClassLoader::perf_app_classload_selftime(),
1665 ClassLoader::perf_app_classload_count(),
1666 jt->get_thread_stat()->perf_recursion_counts_addr(),
1667 jt->get_thread_stat()->perf_timers_addr(),
1668 PerfClassTraceTime::CLASS_LOAD);
1669
1670 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_NULL);
1671 // Translate to external class name format, i.e., convert '/' chars to '.'
1672 Handle string = java_lang_String::externalize_classname(s, CHECK_NULL);
1673
1674 JavaValue result(T_OBJECT);
1675
1676 InstanceKlass* spec_klass = SystemDictionary::ClassLoader_klass();
1677
1678 // Call public unsynchronized loadClass(String) directly for all class loaders.
1679 // For parallelCapable class loaders, JDK >=7, loadClass(String, boolean) will
1680 // acquire a class-name based lock rather than the class loader object lock.
1681 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean).
1682 JavaCalls::call_virtual(&result,
1683 class_loader,
1684 spec_klass,
1685 vmSymbols::loadClass_name(),
1686 vmSymbols::string_class_signature(),
1687 string,
1688 CHECK_NULL);
1689
1690 assert(result.get_type() == T_OBJECT, "just checking");
1691 oop obj = (oop) result.get_jobject();
1692
1693 // Primitive classes return null since forName() can not be
1694 // used to obtain any of the Class objects representing primitives or void
1695 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1696 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(obj));
1697 // For user defined Java class loaders, check that the name returned is
1698 // the same as that requested. This check is done for the bootstrap
1699 // loader when parsing the class file.
1700 if (class_name == k->name()) {
1701 return k;
1702 }
1703 }
1704 // Class is not found or has the wrong name, return NULL
1705 return NULL;
1706 }
1707 }
1708
1709 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1710 EventClassDefine event;
1711 if (event.should_commit()) {
1712 event.set_definedClass(k);
1713 event.set_definingClassLoader(def_cld);
1714 event.commit();
1715 }
1716 }
1717
1718 void SystemDictionary::define_instance_class(InstanceKlass* k, TRAPS) {
1719
1720 HandleMark hm(THREAD);
1721 ClassLoaderData* loader_data = k->class_loader_data();
1722 Handle class_loader_h(THREAD, loader_data->class_loader());
1723
1724 // for bootstrap and other parallel classloaders don't acquire lock,
1725 // use placeholder token
1726 // If a parallelCapable class loader calls define_instance_class instead of
1727 // find_or_define_instance_class to get here, we have a timing
1728 // hole with systemDictionary updates and check_constraints
1729 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1730 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1731 compute_loader_lock_object(class_loader_h, THREAD)),
1732 "define called without lock");
1733 }
1734
1735 // Check class-loading constraints. Throw exception if violation is detected.
1736 // Grabs and releases SystemDictionary_lock
1737 // The check_constraints/find_class call and update_dictionary sequence
1738 // must be "atomic" for a specific class/classloader pair so we never
1739 // define two different instanceKlasses for that class/classloader pair.
1740 // Existing classloaders will call define_instance_class with the
1741 // classloader lock held
1742 // Parallel classloaders will call find_or_define_instance_class
1743 // which will require a token to perform the define class
1744 Symbol* name_h = k->name();
1745 Dictionary* dictionary = loader_data->dictionary();
1746 unsigned int d_hash = dictionary->compute_hash(name_h);
1747 check_constraints(d_hash, k, class_loader_h, true, CHECK);
1748
1749 // Register class just loaded with class loader (placed in ArrayList)
1750 // Note we do this before updating the dictionary, as this can
1751 // fail with an OutOfMemoryError (if it does, we will *not* put this
1752 // class in the dictionary and will not update the class hierarchy).
1753 // JVMTI FollowReferences needs to find the classes this way.
1754 if (k->class_loader() != NULL) {
1755 methodHandle m(THREAD, Universe::loader_addClass_method());
1756 JavaValue result(T_VOID);
1757 JavaCallArguments args(class_loader_h);
1758 args.push_oop(Handle(THREAD, k->java_mirror()));
1759 JavaCalls::call(&result, m, &args, CHECK);
1760 }
1761
1762 // Add the new class. We need recompile lock during update of CHA.
1763 {
1764 unsigned int p_hash = placeholders()->compute_hash(name_h);
1765 int p_index = placeholders()->hash_to_index(p_hash);
1766
1767 MutexLocker mu_r(THREAD, Compile_lock);
1768
1769 // Add to class hierarchy, initialize vtables, and do possible
1770 // deoptimizations.
1771 add_to_hierarchy(k, CHECK); // No exception, but can block
1772
1773 // Add to systemDictionary - so other classes can see it.
1774 // Grabs and releases SystemDictionary_lock
1775 update_dictionary(d_hash, p_index, p_hash,
1776 k, class_loader_h, THREAD);
1777 }
1778 k->eager_initialize(THREAD);
1779
1780 // notify jvmti
1781 if (JvmtiExport::should_post_class_load()) {
1782 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1783 JvmtiExport::post_class_load((JavaThread *) THREAD, k);
1784
1785 }
1786 post_class_define_event(k, loader_data);
1787 }
1788
1789 // Support parallel classloading
1790 // All parallel class loaders, including bootstrap classloader
1791 // lock a placeholder entry for this class/class_loader pair
1792 // to allow parallel defines of different classes for this class loader
1793 // With AllowParallelDefine flag==true, in case they do not synchronize around
1794 // FindLoadedClass/DefineClass, calls, we check for parallel
1795 // loading for them, wait if a defineClass is in progress
1796 // and return the initial requestor's results
1797 // This flag does not apply to the bootstrap classloader.
1798 // With AllowParallelDefine flag==false, call through to define_instance_class
1799 // which will throw LinkageError: duplicate class definition.
1800 // False is the requested default.
1801 // For better performance, the class loaders should synchronize
1802 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1803 // potentially waste time reading and parsing the bytestream.
1804 // Note: VM callers should ensure consistency of k/class_name,class_loader
1805 // Be careful when modifying this code: once you have run
1806 // placeholders()->find_and_add(PlaceholderTable::DEFINE_CLASS),
1807 // you need to find_and_remove it before returning.
1808 // So be careful to not exit with a CHECK_ macro betweeen these calls.
1809 InstanceKlass* SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader,
1810 InstanceKlass* k, TRAPS) {
1811
1812 Symbol* name_h = k->name(); // passed in class_name may be null
1813 ClassLoaderData* loader_data = class_loader_data(class_loader);
1814 Dictionary* dictionary = loader_data->dictionary();
1815
1816 unsigned int d_hash = dictionary->compute_hash(name_h);
1817
1818 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1819 unsigned int p_hash = placeholders()->compute_hash(name_h);
1820 int p_index = placeholders()->hash_to_index(p_hash);
1821 PlaceholderEntry* probe;
1822
1823 {
1824 MutexLocker mu(THREAD, SystemDictionary_lock);
1825 // First check if class already defined
1826 if (is_parallelDefine(class_loader)) {
1827 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1828 if (check != NULL) {
1829 return check;
1830 }
1831 }
1832
1833 // Acquire define token for this class/classloader
1834 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1835 // Wait if another thread defining in parallel
1836 // All threads wait - even those that will throw duplicate class: otherwise
1837 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1838 // if other thread has not finished updating dictionary
1839 while (probe->definer() != NULL) {
1840 SystemDictionary_lock->wait();
1841 }
1842 // Only special cases allow parallel defines and can use other thread's results
1843 // Other cases fall through, and may run into duplicate defines
1844 // caught by finding an entry in the SystemDictionary
1845 if (is_parallelDefine(class_loader) && (probe->instance_klass() != NULL)) {
1846 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1847 SystemDictionary_lock->notify_all();
1848 #ifdef ASSERT
1849 InstanceKlass* check = find_class(d_hash, name_h, dictionary);
1850 assert(check != NULL, "definer missed recording success");
1851 #endif
1852 return probe->instance_klass();
1853 } else {
1854 // This thread will define the class (even if earlier thread tried and had an error)
1855 probe->set_definer(THREAD);
1856 }
1857 }
1858
1859 define_instance_class(k, THREAD);
1860
1861 Handle linkage_exception = Handle(); // null handle
1862
1863 // definer must notify any waiting threads
1864 {
1865 MutexLocker mu(THREAD, SystemDictionary_lock);
1866 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1867 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1868 if (probe != NULL) {
1869 if (HAS_PENDING_EXCEPTION) {
1870 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1871 CLEAR_PENDING_EXCEPTION;
1872 } else {
1873 probe->set_instance_klass(k);
1874 }
1875 probe->set_definer(NULL);
1876 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1877 SystemDictionary_lock->notify_all();
1878 }
1879 }
1880
1881 // Can't throw exception while holding lock due to rank ordering
1882 if (linkage_exception() != NULL) {
1883 THROW_OOP_(linkage_exception(), NULL); // throws exception and returns
1884 }
1885
1886 return k;
1887 }
1888
1889 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1890 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1891 if (class_loader.is_null()) {
1892 return Handle(THREAD, _system_loader_lock_obj);
1893 } else {
1894 return class_loader;
1895 }
1896 }
1897
1898 // This method is added to check how often we have to wait to grab loader
1899 // lock. The results are being recorded in the performance counters defined in
1900 // ClassLoader::_sync_systemLoaderLockContentionRate and
1901 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1902 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1903 if (!UsePerfData) {
1904 return;
1905 }
1906
1907 assert(!loader_lock.is_null(), "NULL lock object");
1908
1909 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1910 == ObjectSynchronizer::owner_other) {
1911 // contention will likely happen, so increment the corresponding
1912 // contention counter.
1913 if (loader_lock() == _system_loader_lock_obj) {
1914 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1915 } else {
1916 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1917 }
1918 }
1919 }
1920
1921 // ----------------------------------------------------------------------------
1922 // Lookup
1923
1924 InstanceKlass* SystemDictionary::find_class(unsigned int hash,
1925 Symbol* class_name,
1926 Dictionary* dictionary) {
1927 assert_locked_or_safepoint(SystemDictionary_lock);
1928 int index = dictionary->hash_to_index(hash);
1929 return dictionary->find_class(index, hash, class_name);
1930 }
1931
1932
1933 // Basic find on classes in the midst of being loaded
1934 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1935 ClassLoaderData* loader_data) {
1936 assert_locked_or_safepoint(SystemDictionary_lock);
1937 unsigned int p_hash = placeholders()->compute_hash(class_name);
1938 int p_index = placeholders()->hash_to_index(p_hash);
1939 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1940 }
1941
1942
1943 // Used for assertions and verification only
1944 // Precalculating the hash and index is an optimization because there are many lookups
1945 // before adding the class.
1946 InstanceKlass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1947 assert_locked_or_safepoint(SystemDictionary_lock);
1948 #ifndef ASSERT
1949 guarantee(VerifyBeforeGC ||
1950 VerifyDuringGC ||
1951 VerifyBeforeExit ||
1952 VerifyDuringStartup ||
1953 VerifyAfterGC, "too expensive");
1954 #endif
1955
1956 Dictionary* dictionary = loader_data->dictionary();
1957 unsigned int d_hash = dictionary->compute_hash(class_name);
1958 return find_class(d_hash, class_name, dictionary);
1959 }
1960
1961
1962 // ----------------------------------------------------------------------------
1963 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1964 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1965 // before a new class is used.
1966
1967 void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
1968 assert(k != NULL, "just checking");
1969 if (Universe::is_fully_initialized()) {
1970 assert_locked_or_safepoint(Compile_lock);
1971 }
1972
1973 k->set_init_state(InstanceKlass::loaded);
1974 // make sure init_state store is already done.
1975 // The compiler reads the hierarchy outside of the Compile_lock.
1976 // Access ordering is used to add to hierarchy.
1977
1978 // Link into hierachy.
1979 k->append_to_sibling_list(); // add to superklass/sibling list
1980 k->process_interfaces(THREAD); // handle all "implements" declarations
1981
1982 // Now flush all code that depended on old class hierarchy.
1983 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1984 if (Universe::is_fully_initialized()) {
1985 CodeCache::flush_dependents_on(k);
1986 }
1987 }
1988
1989 // ----------------------------------------------------------------------------
1990 // GC support
1991
1992 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1993 // Note: anonymous classes are not in the SD.
1994 bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
1995
1996 bool unloading_occurred;
1997 bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
1998 {
1999 GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
2000 assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
2001 // First, mark for unload all ClassLoaderData referencing a dead class loader.
2002 unloading_occurred = ClassLoaderDataGraph::do_unloading();
2003 if (unloading_occurred) {
2004 MutexLocker ml2(is_concurrent ? Module_lock : NULL);
2005 JFR_ONLY(Jfr::on_unloading_classes();)
2006
2007 MutexLocker ml1(is_concurrent ? SystemDictionary_lock : NULL);
2008 ClassLoaderDataGraph::clean_module_and_package_info();
2009 constraints()->purge_loader_constraints();
2010 resolution_errors()->purge_resolution_errors();
2011 }
2012 }
2013
2014 GCTraceTime(Debug, gc, phases) t("Trigger cleanups", gc_timer);
2015
2016 if (unloading_occurred) {
2017 SymbolTable::trigger_cleanup();
2018
2019 // Oops referenced by the protection domain cache table may get unreachable independently
2020 // of the class loader (eg. cached protection domain oops). So we need to
2021 // explicitly unlink them here.
2022 // All protection domain oops are linked to the caller class, so if nothing
2023 // unloads, this is not needed.
2024 _pd_cache_table->trigger_cleanup();
2025 }
2026
2027 return unloading_occurred;
2028 }
2029
2030 void SystemDictionary::oops_do(OopClosure* f, bool include_handles) {
2031 f->do_oop(&_java_system_loader);
2032 f->do_oop(&_java_platform_loader);
2033 f->do_oop(&_system_loader_lock_obj);
2034 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
2035
2036 // Visit extra methods
2037 invoke_method_table()->oops_do(f);
2038
2039 if (include_handles) {
2040 OopStorageSet::vm_global()->oops_do(f);
2041 }
2042 }
2043
2044 // CDS: scan and relocate all classes referenced by _well_known_klasses[].
2045 void SystemDictionary::well_known_klasses_do(MetaspaceClosure* it) {
2046 for (int id = FIRST_WKID; id < WKID_LIMIT; id++) {
2047 it->push(well_known_klass_addr((WKID)id));
2048 }
2049 }
2050
2051 void SystemDictionary::methods_do(void f(Method*)) {
2052 // Walk methods in loaded classes
2053 MutexLocker ml(ClassLoaderDataGraph_lock);
2054 ClassLoaderDataGraph::methods_do(f);
2055 // Walk method handle intrinsics
2056 invoke_method_table()->methods_do(f);
2057 }
2058
2059 // ----------------------------------------------------------------------------
2060 // Initialization
2061
2062 void SystemDictionary::initialize(TRAPS) {
2063 // Allocate arrays
2064 _placeholders = new PlaceholderTable(_placeholder_table_size);
2065 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
2066 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
2067 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
2068 _pd_cache_table = new ProtectionDomainCacheTable(defaultProtectionDomainCacheSize);
2069
2070 // Allocate private object used as system class loader lock
2071 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
2072 // Initialize basic classes
2073 resolve_well_known_classes(CHECK);
2074 }
2075
2076 // Compact table of directions on the initialization of klasses:
2077 static const short wk_init_info[] = {
2078 #define WK_KLASS_INIT_INFO(name, symbol) \
2079 ((short)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol)),
2080
2081 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
2082 #undef WK_KLASS_INIT_INFO
2083 0
2084 };
2085
2086 #ifdef ASSERT
2087 bool SystemDictionary::is_well_known_klass(Symbol* class_name) {
2088 int sid;
2089 for (int i = 0; (sid = wk_init_info[i]) != 0; i++) {
2090 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2091 if (class_name == symbol) {
2092 return true;
2093 }
2094 }
2095 return false;
2096 }
2097 #endif
2098
2099 bool SystemDictionary::resolve_wk_klass(WKID id, TRAPS) {
2100 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2101 int sid = wk_init_info[id - FIRST_WKID];
2102 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
2103 InstanceKlass** klassp = &_well_known_klasses[id];
2104
2105 #if INCLUDE_CDS
2106 if (UseSharedSpaces && !JvmtiExport::should_post_class_prepare()) {
2107 InstanceKlass* k = *klassp;
2108 assert(k->is_shared_boot_class(), "must be");
2109
2110 ClassLoaderData* loader_data = ClassLoaderData::the_null_class_loader_data();
2111 quick_resolve(k, loader_data, Handle(), CHECK_false);
2112 return true;
2113 }
2114 #endif // INCLUDE_CDS
2115
2116 if (!is_wk_klass_loaded(*klassp)) {
2117 Klass* k = resolve_or_fail(symbol, true, CHECK_false);
2118 (*klassp) = InstanceKlass::cast(k);
2119 }
2120 return ((*klassp) != NULL);
2121 }
2122
2123 void SystemDictionary::resolve_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
2124 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
2125 for (int id = (int)start_id; id < (int)limit_id; id++) {
2126 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
2127 resolve_wk_klass((WKID)id, CHECK);
2128 }
2129
2130 // move the starting value forward to the limit:
2131 start_id = limit_id;
2132 }
2133
2134 void SystemDictionary::resolve_well_known_classes(TRAPS) {
2135 assert(!Object_klass_loaded(), "well-known classes should only be initialized once");
2136
2137 // Create the ModuleEntry for java.base. This call needs to be done here,
2138 // after vmSymbols::initialize() is called but before any classes are pre-loaded.
2139 ClassLoader::classLoader_init2(CHECK);
2140
2141 // Preload commonly used klasses
2142 WKID scan = FIRST_WKID;
2143 // first do Object, then String, Class
2144 #if INCLUDE_CDS
2145 if (UseSharedSpaces) {
2146 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
2147
2148 // It's unsafe to access the archived heap regions before they
2149 // are fixed up, so we must do the fixup as early as possible
2150 // before the archived java objects are accessed by functions
2151 // such as java_lang_Class::restore_archived_mirror and
2152 // ConstantPool::restore_unshareable_info (restores the archived
2153 // resolved_references array object).
2154 //
2155 // HeapShared::fixup_mapped_heap_regions() fills the empty
2156 // spaces in the archived heap regions and may use
2157 // SystemDictionary::Object_klass(), so we can do this only after
2158 // Object_klass is resolved. See the above resolve_wk_klasses_through()
2159 // call. No mirror objects are accessed/restored in the above call.
2160 // Mirrors are restored after java.lang.Class is loaded.
2161 HeapShared::fixup_mapped_heap_regions();
2162
2163 // Initialize the constant pool for the Object_class
2164 assert(Object_klass()->is_shared(), "must be");
2165 Object_klass()->constants()->restore_unshareable_info(CHECK);
2166 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2167 } else
2168 #endif
2169 {
2170 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
2171 }
2172
2173 assert(WK_KLASS(Object_klass) != NULL, "well-known classes should now be initialized");
2174
2175 java_lang_Object::register_natives(CHECK);
2176
2177 // Calculate offsets for String and Class classes since they are loaded and
2178 // can be used after this point.
2179 java_lang_String::compute_offsets();
2180 java_lang_Class::compute_offsets();
2181
2182 // Fixup mirrors for classes loaded before java.lang.Class.
2183 Universe::initialize_basic_type_mirrors(CHECK);
2184 Universe::fixup_mirrors(CHECK);
2185
2186 // do a bunch more:
2187 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2188
2189 // The offsets for jlr.Reference must be computed before
2190 // InstanceRefKlass::update_nonstatic_oop_maps is called. That function uses
2191 // the offsets to remove the referent and discovered fields from the oop maps,
2192 // as they are treated in a special way by the GC. Removing these oops from the
2193 // oop maps must be done before the usual subclasses of jlr.Reference are loaded.
2194 java_lang_ref_Reference::compute_offsets();
2195
2196 // Preload ref klasses and set reference types
2197 WK_KLASS(Reference_klass)->set_reference_type(REF_OTHER);
2198 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2199
2200 resolve_wk_klasses_through(WK_KLASS_ENUM_NAME(PhantomReference_klass), scan, CHECK);
2201 WK_KLASS(SoftReference_klass)->set_reference_type(REF_SOFT);
2202 WK_KLASS(WeakReference_klass)->set_reference_type(REF_WEAK);
2203 WK_KLASS(FinalReference_klass)->set_reference_type(REF_FINAL);
2204 WK_KLASS(PhantomReference_klass)->set_reference_type(REF_PHANTOM);
2205
2206 // JSR 292 classes
2207 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2208 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2209 resolve_wk_klasses_until(jsr292_group_start, scan, CHECK);
2210 resolve_wk_klasses_through(jsr292_group_end, scan, CHECK);
2211 WKID last = WKID_LIMIT;
2212 resolve_wk_klasses_until(last, scan, CHECK);
2213
2214 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2215 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2216 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2217 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2218 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2219 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2220 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2221 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2222 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2223 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2224
2225 #ifdef ASSERT
2226 if (UseSharedSpaces) {
2227 JVMTI_ONLY(assert(JvmtiExport::is_early_phase(),
2228 "All well known classes must be resolved in JVMTI early phase"));
2229 for (int i = FIRST_WKID; i < last; i++) {
2230 InstanceKlass* k = _well_known_klasses[i];
2231 assert(k->is_shared(), "must not be replaced by JVMTI class file load hook");
2232 }
2233 }
2234 #endif
2235 }
2236
2237 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2238 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2239 BasicType SystemDictionary::box_klass_type(Klass* k) {
2240 assert(k != NULL, "");
2241 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2242 if (_box_klasses[i] == k)
2243 return (BasicType)i;
2244 }
2245 return T_OBJECT;
2246 }
2247
2248 // Constraints on class loaders. The details of the algorithm can be
2249 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2250 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2251 // that the dictionary needs to maintain a set of contraints that
2252 // must be satisfied by all classes in the dictionary.
2253 // if defining is true, then LinkageError if already in dictionary
2254 // if initiating loader, then ok if InstanceKlass matches existing entry
2255
2256 void SystemDictionary::check_constraints(unsigned int d_hash,
2257 InstanceKlass* k,
2258 Handle class_loader,
2259 bool defining,
2260 TRAPS) {
2261 ResourceMark rm(THREAD);
2262 stringStream ss;
2263 bool throwException = false;
2264
2265 {
2266 Symbol *name = k->name();
2267 ClassLoaderData *loader_data = class_loader_data(class_loader);
2268
2269 MutexLocker mu(THREAD, SystemDictionary_lock);
2270
2271 InstanceKlass* check = find_class(d_hash, name, loader_data->dictionary());
2272 if (check != NULL) {
2273 // If different InstanceKlass - duplicate class definition,
2274 // else - ok, class loaded by a different thread in parallel.
2275 // We should only have found it if it was done loading and ok to use.
2276 // The dictionary only holds instance classes, placeholders
2277 // also hold array classes.
2278
2279 assert(check->is_instance_klass(), "noninstance in systemdictionary");
2280 if ((defining == true) || (k != check)) {
2281 throwException = true;
2282 ss.print("loader %s", loader_data->loader_name_and_id());
2283 ss.print(" attempted duplicate %s definition for %s. (%s)",
2284 k->external_kind(), k->external_name(), k->class_in_module_of_loader(false, true));
2285 } else {
2286 return;
2287 }
2288 }
2289
2290 #ifdef ASSERT
2291 Symbol* ph_check = find_placeholder(name, loader_data);
2292 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2293 #endif
2294
2295 if (throwException == false) {
2296 if (constraints()->check_or_update(k, class_loader, name) == false) {
2297 throwException = true;
2298 ss.print("loader constraint violation: loader %s", loader_data->loader_name_and_id());
2299 ss.print(" wants to load %s %s.",
2300 k->external_kind(), k->external_name());
2301 Klass *existing_klass = constraints()->find_constrained_klass(name, class_loader);
2302 if (existing_klass != NULL && existing_klass->class_loader() != class_loader()) {
2303 ss.print(" A different %s with the same name was previously loaded by %s. (%s)",
2304 existing_klass->external_kind(),
2305 existing_klass->class_loader_data()->loader_name_and_id(),
2306 existing_klass->class_in_module_of_loader(false, true));
2307 } else {
2308 ss.print(" (%s)", k->class_in_module_of_loader(false, true));
2309 }
2310 }
2311 }
2312 }
2313
2314 // Throw error now if needed (cannot throw while holding
2315 // SystemDictionary_lock because of rank ordering)
2316 if (throwException == true) {
2317 THROW_MSG(vmSymbols::java_lang_LinkageError(), ss.as_string());
2318 }
2319 }
2320
2321 // Update class loader data dictionary - done after check_constraint and add_to_hierachy
2322 // have been called.
2323 void SystemDictionary::update_dictionary(unsigned int d_hash,
2324 int p_index, unsigned int p_hash,
2325 InstanceKlass* k,
2326 Handle class_loader,
2327 TRAPS) {
2328 // Compile_lock prevents systemDictionary updates during compilations
2329 assert_locked_or_safepoint(Compile_lock);
2330 Symbol* name = k->name();
2331 ClassLoaderData *loader_data = class_loader_data(class_loader);
2332
2333 {
2334 MutexLocker mu1(THREAD, SystemDictionary_lock);
2335
2336 // Make a new dictionary entry.
2337 Dictionary* dictionary = loader_data->dictionary();
2338 InstanceKlass* sd_check = find_class(d_hash, name, dictionary);
2339 if (sd_check == NULL) {
2340 dictionary->add_klass(d_hash, name, k);
2341 }
2342 #ifdef ASSERT
2343 sd_check = find_class(d_hash, name, dictionary);
2344 assert (sd_check != NULL, "should have entry in dictionary");
2345 // Note: there may be a placeholder entry: for circularity testing
2346 // or for parallel defines
2347 #endif
2348 SystemDictionary_lock->notify_all();
2349 }
2350 }
2351
2352
2353 // Try to find a class name using the loader constraints. The
2354 // loader constraints might know about a class that isn't fully loaded
2355 // yet and these will be ignored.
2356 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2357 Symbol* class_name, Handle class_loader, TRAPS) {
2358
2359 // First see if it has been loaded directly.
2360 // Force the protection domain to be null. (This removes protection checks.)
2361 Handle no_protection_domain;
2362 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2363 no_protection_domain, CHECK_NULL);
2364 if (klass != NULL)
2365 return klass;
2366
2367 // Now look to see if it has been loaded elsewhere, and is subject to
2368 // a loader constraint that would require this loader to return the
2369 // klass that is already loaded.
2370 if (Signature::is_array(class_name)) {
2371 // For array classes, their Klass*s are not kept in the
2372 // constraint table. The element Klass*s are.
2373 SignatureStream ss(class_name, false);
2374 int ndims = ss.skip_array_prefix(); // skip all '['s
2375 BasicType t = ss.type();
2376 if (t != T_OBJECT) {
2377 klass = Universe::typeArrayKlassObj(t);
2378 } else {
2379 MutexLocker mu(THREAD, SystemDictionary_lock);
2380 klass = constraints()->find_constrained_klass(ss.as_symbol(), class_loader);
2381 }
2382 // If element class already loaded, allocate array klass
2383 if (klass != NULL) {
2384 klass = klass->array_klass_or_null(ndims);
2385 }
2386 } else {
2387 MutexLocker mu(THREAD, SystemDictionary_lock);
2388 // Non-array classes are easy: simply check the constraint table.
2389 klass = constraints()->find_constrained_klass(class_name, class_loader);
2390 }
2391
2392 return klass;
2393 }
2394
2395 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2396 Klass* klass_being_linked,
2397 Handle class_loader1,
2398 Handle class_loader2,
2399 Thread* THREAD) {
2400 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2401 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2402
2403 Symbol* constraint_name = NULL;
2404
2405 if (!Signature::is_array(class_name)) {
2406 constraint_name = class_name;
2407 } else {
2408 // For array classes, their Klass*s are not kept in the
2409 // constraint table. The element classes are.
2410 SignatureStream ss(class_name, false);
2411 ss.skip_array_prefix(); // skip all '['s
2412 if (!ss.has_envelope()) {
2413 return true; // primitive types always pass
2414 }
2415 constraint_name = ss.as_symbol();
2416 // Increment refcount to keep constraint_name alive after
2417 // SignatureStream is destructed. It will be decremented below
2418 // before returning.
2419 constraint_name->increment_refcount();
2420 }
2421
2422 Dictionary* dictionary1 = loader_data1->dictionary();
2423 unsigned int d_hash1 = dictionary1->compute_hash(constraint_name);
2424
2425 Dictionary* dictionary2 = loader_data2->dictionary();
2426 unsigned int d_hash2 = dictionary2->compute_hash(constraint_name);
2427
2428 {
2429 MutexLocker mu_s(THREAD, SystemDictionary_lock);
2430 InstanceKlass* klass1 = find_class(d_hash1, constraint_name, dictionary1);
2431 InstanceKlass* klass2 = find_class(d_hash2, constraint_name, dictionary2);
2432 bool result = constraints()->add_entry(constraint_name, klass1, class_loader1,
2433 klass2, class_loader2);
2434 #if INCLUDE_CDS
2435 if (Arguments::is_dumping_archive() && klass_being_linked != NULL &&
2436 !klass_being_linked->is_shared()) {
2437 SystemDictionaryShared::record_linking_constraint(constraint_name,
2438 InstanceKlass::cast(klass_being_linked),
2439 class_loader1, class_loader2, THREAD);
2440 }
2441 #endif // INCLUDE_CDS
2442 if (Signature::is_array(class_name)) {
2443 constraint_name->decrement_refcount();
2444 }
2445 return result;
2446 }
2447 }
2448
2449 // Add entry to resolution error table to record the error when the first
2450 // attempt to resolve a reference to a class has failed.
2451 void SystemDictionary::add_resolution_error(const constantPoolHandle& pool, int which,
2452 Symbol* error, Symbol* message) {
2453 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2454 int index = resolution_errors()->hash_to_index(hash);
2455 {
2456 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2457 resolution_errors()->add_entry(index, hash, pool, which, error, message);
2458 }
2459 }
2460
2461 // Delete a resolution error for RedefineClasses for a constant pool is going away
2462 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2463 resolution_errors()->delete_entry(pool);
2464 }
2465
2466 // Lookup resolution error table. Returns error if found, otherwise NULL.
2467 Symbol* SystemDictionary::find_resolution_error(const constantPoolHandle& pool, int which,
2468 Symbol** message) {
2469 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2470 int index = resolution_errors()->hash_to_index(hash);
2471 {
2472 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2473 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2474 if (entry != NULL) {
2475 *message = entry->message();
2476 return entry->error();
2477 } else {
2478 return NULL;
2479 }
2480 }
2481 }
2482
2483 // Add an entry to resolution error table to record an error in resolving or
2484 // validating a nest host. This is used to construct informative error
2485 // messages when IllegalAccessError's occur. If an entry already exists it will
2486 // be updated with the nest host error message.
2487 void SystemDictionary::add_nest_host_error(const constantPoolHandle& pool,
2488 int which,
2489 const char* message) {
2490 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2491 int index = resolution_errors()->hash_to_index(hash);
2492 {
2493 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2494 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2495 if (entry != NULL) {
2496 assert(entry->nest_host_error() == NULL, "Nest host error message already set!");
2497 entry->set_nest_host_error(message);
2498 } else {
2499 resolution_errors()->add_entry(index, hash, pool, which, message);
2500 }
2501 }
2502 }
2503
2504 // Lookup any nest host error
2505 const char* SystemDictionary::find_nest_host_error(const constantPoolHandle& pool, int which) {
2506 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2507 int index = resolution_errors()->hash_to_index(hash);
2508 {
2509 MutexLocker ml(Thread::current(), SystemDictionary_lock);
2510 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2511 if (entry != NULL) {
2512 return entry->nest_host_error();
2513 } else {
2514 return NULL;
2515 }
2516 }
2517 }
2518
2519
2520 // Signature constraints ensure that callers and callees agree about
2521 // the meaning of type names in their signatures. This routine is the
2522 // intake for constraints. It collects them from several places:
2523 //
2524 // * LinkResolver::resolve_method (if check_access is true) requires
2525 // that the resolving class (the caller) and the defining class of
2526 // the resolved method (the callee) agree on each type in the
2527 // method's signature.
2528 //
2529 // * LinkResolver::resolve_interface_method performs exactly the same
2530 // checks.
2531 //
2532 // * LinkResolver::resolve_field requires that the constant pool
2533 // attempting to link to a field agree with the field's defining
2534 // class about the type of the field signature.
2535 //
2536 // * klassVtable::initialize_vtable requires that, when a class
2537 // overrides a vtable entry allocated by a superclass, that the
2538 // overriding method (i.e., the callee) agree with the superclass
2539 // on each type in the method's signature.
2540 //
2541 // * klassItable::initialize_itable requires that, when a class fills
2542 // in its itables, for each non-abstract method installed in an
2543 // itable, the method (i.e., the callee) agree with the interface
2544 // on each type in the method's signature.
2545 //
2546 // All those methods have a boolean (check_access, checkconstraints)
2547 // which turns off the checks. This is used from specialized contexts
2548 // such as bootstrapping, dumping, and debugging.
2549 //
2550 // No direct constraint is placed between the class and its
2551 // supertypes. Constraints are only placed along linked relations
2552 // between callers and callees. When a method overrides or implements
2553 // an abstract method in a supertype (superclass or interface), the
2554 // constraints are placed as if the supertype were the caller to the
2555 // overriding method. (This works well, since callers to the
2556 // supertype have already established agreement between themselves and
2557 // the supertype.) As a result of all this, a class can disagree with
2558 // its supertype about the meaning of a type name, as long as that
2559 // class neither calls a relevant method of the supertype, nor is
2560 // called (perhaps via an override) from the supertype.
2561 //
2562 //
2563 // SystemDictionary::check_signature_loaders(sig, klass_being_linked, l1, l2)
2564 //
2565 // Make sure all class components (including arrays) in the given
2566 // signature will be resolved to the same class in both loaders.
2567 // Returns the name of the type that failed a loader constraint check, or
2568 // NULL if no constraint failed. No exception except OOME is thrown.
2569 // Arrays are not added to the loader constraint table, their elements are.
2570 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2571 Klass* klass_being_linked,
2572 Handle loader1, Handle loader2,
2573 bool is_method, TRAPS) {
2574 // Nothing to do if loaders are the same.
2575 if (loader1() == loader2()) {
2576 return NULL;
2577 }
2578
2579 for (SignatureStream ss(signature, is_method); !ss.is_done(); ss.next()) {
2580 if (ss.is_reference()) {
2581 Symbol* sig = ss.as_symbol();
2582 // Note: In the future, if template-like types can take
2583 // arguments, we will want to recognize them and dig out class
2584 // names hiding inside the argument lists.
2585 if (!add_loader_constraint(sig, klass_being_linked, loader1, loader2, THREAD)) {
2586 return sig;
2587 }
2588 }
2589 }
2590 return NULL;
2591 }
2592
2593 Method* SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2594 Symbol* signature,
2595 TRAPS) {
2596 methodHandle empty;
2597 assert(MethodHandles::is_signature_polymorphic(iid) &&
2598 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2599 iid != vmIntrinsics::_invokeGeneric,
2600 "must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid));
2601
2602 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2603 int index = invoke_method_table()->hash_to_index(hash);
2604 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2605 methodHandle m;
2606 if (spe == NULL || spe->method() == NULL) {
2607 spe = NULL;
2608 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2609 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_NULL);
2610 if (!Arguments::is_interpreter_only()) {
2611 // Generate a compiled form of the MH intrinsic.
2612 AdapterHandlerLibrary::create_native_wrapper(m);
2613 // Check if have the compiled code.
2614 if (!m->has_compiled_code()) {
2615 THROW_MSG_NULL(vmSymbols::java_lang_VirtualMachineError(),
2616 "Out of space in CodeCache for method handle intrinsic");
2617 }
2618 }
2619 // Now grab the lock. We might have to throw away the new method,
2620 // if a racing thread has managed to install one at the same time.
2621 {
2622 MutexLocker ml(THREAD, SystemDictionary_lock);
2623 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2624 if (spe == NULL)
2625 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2626 if (spe->method() == NULL)
2627 spe->set_method(m());
2628 }
2629 }
2630
2631 assert(spe != NULL && spe->method() != NULL, "");
2632 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2633 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2634 "MH intrinsic invariant");
2635 return spe->method();
2636 }
2637
2638 // Helper for unpacking the return value from linkMethod and linkCallSite.
2639 static Method* unpack_method_and_appendix(Handle mname,
2640 Klass* accessing_klass,
2641 objArrayHandle appendix_box,
2642 Handle* appendix_result,
2643 TRAPS) {
2644 if (mname.not_null()) {
2645 Method* m = java_lang_invoke_MemberName::vmtarget(mname());
2646 if (m != NULL) {
2647 oop appendix = appendix_box->obj_at(0);
2648 LogTarget(Info, methodhandles) lt;
2649 if (lt.develop_is_enabled()) {
2650 ResourceMark rm(THREAD);
2651 LogStream ls(lt);
2652 ls.print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2653 m->print_on(&ls);
2654 if (appendix != NULL) { ls.print("appendix = "); appendix->print_on(&ls); }
2655 ls.cr();
2656 }
2657
2658 (*appendix_result) = Handle(THREAD, appendix);
2659 // the target is stored in the cpCache and if a reference to this
2660 // MemberName is dropped we need a way to make sure the
2661 // class_loader containing this method is kept alive.
2662 methodHandle mh(THREAD, m); // record_dependency can safepoint.
2663 ClassLoaderData* this_key = accessing_klass->class_loader_data();
2664 this_key->record_dependency(m->method_holder());
2665 return mh();
2666 }
2667 }
2668 THROW_MSG_NULL(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives");
2669 }
2670
2671 Method* SystemDictionary::find_method_handle_invoker(Klass* klass,
2672 Symbol* name,
2673 Symbol* signature,
2674 Klass* accessing_klass,
2675 Handle *appendix_result,
2676 TRAPS) {
2677 assert(THREAD->can_call_java() ,"");
2678 Handle method_type =
2679 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_NULL);
2680
2681 int ref_kind = JVM_REF_invokeVirtual;
2682 oop name_oop = StringTable::intern(name, CHECK_NULL);
2683 Handle name_str (THREAD, name_oop);
2684 objArrayHandle appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK_NULL);
2685 assert(appendix_box->obj_at(0) == NULL, "");
2686
2687 // This should not happen. JDK code should take care of that.
2688 if (accessing_klass == NULL || method_type.is_null()) {
2689 THROW_MSG_NULL(vmSymbols::java_lang_InternalError(), "bad invokehandle");
2690 }
2691
2692 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2693 JavaCallArguments args;
2694 args.push_oop(Handle(THREAD, accessing_klass->java_mirror()));
2695 args.push_int(ref_kind);
2696 args.push_oop(Handle(THREAD, klass->java_mirror()));
2697 args.push_oop(name_str);
2698 args.push_oop(method_type);
2699 args.push_oop(appendix_box);
2700 JavaValue result(T_OBJECT);
2701 JavaCalls::call_static(&result,
2702 SystemDictionary::MethodHandleNatives_klass(),
2703 vmSymbols::linkMethod_name(),
2704 vmSymbols::linkMethod_signature(),
2705 &args, CHECK_NULL);
2706 Handle mname(THREAD, (oop) result.get_jobject());
2707 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2708 }
2709
2710 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2711 // We must ensure that all class loaders everywhere will reach this class, for any client.
2712 // This is a safe bet for public classes in java.lang, such as Object and String.
2713 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2714 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2715 static bool is_always_visible_class(oop mirror) {
2716 Klass* klass = java_lang_Class::as_Klass(mirror);
2717 if (klass->is_objArray_klass()) {
2718 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2719 }
2720 if (klass->is_typeArray_klass()) {
2721 return true; // primitive array
2722 }
2723 assert(klass->is_instance_klass(), "%s", klass->external_name());
2724 return klass->is_public() &&
2725 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2726 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2727 }
2728
2729 // Find or construct the Java mirror (java.lang.Class instance) for
2730 // the given field type signature, as interpreted relative to the
2731 // given class loader. Handles primitives, void, references, arrays,
2732 // and all other reflectable types, except method types.
2733 // N.B. Code in reflection should use this entry point.
2734 Handle SystemDictionary::find_java_mirror_for_type(Symbol* signature,
2735 Klass* accessing_klass,
2736 Handle class_loader,
2737 Handle protection_domain,
2738 SignatureStream::FailureMode failure_mode,
2739 TRAPS) {
2740 assert(accessing_klass == NULL || (class_loader.is_null() && protection_domain.is_null()),
2741 "one or the other, or perhaps neither");
2742
2743 // What we have here must be a valid field descriptor,
2744 // and all valid field descriptors are supported.
2745 // Produce the same java.lang.Class that reflection reports.
2746 if (accessing_klass != NULL) {
2747 class_loader = Handle(THREAD, accessing_klass->class_loader());
2748 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2749 }
2750 ResolvingSignatureStream ss(signature, class_loader, protection_domain, false);
2751 oop mirror_oop = ss.as_java_mirror(failure_mode, CHECK_NH);
2752 if (mirror_oop == NULL) {
2753 return Handle(); // report failure this way
2754 }
2755 Handle mirror(THREAD, mirror_oop);
2756
2757 if (accessing_klass != NULL) {
2758 // Check accessibility, emulating ConstantPool::verify_constant_pool_resolve.
2759 Klass* sel_klass = java_lang_Class::as_Klass(mirror());
2760 if (sel_klass != NULL) {
2761 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_NH);
2762 }
2763 }
2764 return mirror;
2765 }
2766
2767
2768 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2769 // signature, as interpreted relative to the given class loader.
2770 // Because of class loader constraints, all method handle usage must be
2771 // consistent with this loader.
2772 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2773 Klass* accessing_klass,
2774 TRAPS) {
2775 Handle empty;
2776 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2777 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2778 int index = invoke_method_table()->hash_to_index(hash);
2779 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2780 if (spe != NULL && spe->method_type() != NULL) {
2781 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2782 return Handle(THREAD, spe->method_type());
2783 } else if (!THREAD->can_call_java()) {
2784 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2785 return Handle(); // do not attempt from within compiler, unless it was cached
2786 }
2787
2788 Handle class_loader, protection_domain;
2789 if (accessing_klass != NULL) {
2790 class_loader = Handle(THREAD, accessing_klass->class_loader());
2791 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2792 }
2793 bool can_be_cached = true;
2794 int npts = ArgumentCount(signature).size();
2795 objArrayHandle pts = oopFactory::new_objArray_handle(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2796 int arg = 0;
2797 Handle rt; // the return type from the signature
2798 ResourceMark rm(THREAD);
2799 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2800 oop mirror = NULL;
2801 if (can_be_cached) {
2802 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2803 mirror = ss.as_java_mirror(Handle(), Handle(),
2804 SignatureStream::ReturnNull, CHECK_(empty));
2805 if (mirror == NULL || (ss.is_reference() && !is_always_visible_class(mirror))) {
2806 // Fall back to accessing_klass context.
2807 can_be_cached = false;
2808 }
2809 }
2810 if (!can_be_cached) {
2811 // Resolve, throwing a real error if it doesn't work.
2812 mirror = ss.as_java_mirror(class_loader, protection_domain,
2813 SignatureStream::NCDFError, CHECK_(empty));
2814 }
2815 assert(mirror != NULL, "%s", ss.as_symbol()->as_C_string());
2816 if (ss.at_return_type())
2817 rt = Handle(THREAD, mirror);
2818 else
2819 pts->obj_at_put(arg++, mirror);
2820
2821 // Check accessibility.
2822 if (!java_lang_Class::is_primitive(mirror) && accessing_klass != NULL) {
2823 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2824 mirror = NULL; // safety
2825 // Emulate ConstantPool::verify_constant_pool_resolve.
2826 LinkResolver::check_klass_accessibility(accessing_klass, sel_klass, CHECK_(empty));
2827 }
2828 }
2829 assert(arg == npts, "");
2830
2831 // call java.lang.invoke.MethodHandleNatives::findMethodHandleType(Class rt, Class[] pts) -> MethodType
2832 JavaCallArguments args(Handle(THREAD, rt()));
2833 args.push_oop(pts);
2834 JavaValue result(T_OBJECT);
2835 JavaCalls::call_static(&result,
2836 SystemDictionary::MethodHandleNatives_klass(),
2837 vmSymbols::findMethodHandleType_name(),
2838 vmSymbols::findMethodHandleType_signature(),
2839 &args, CHECK_(empty));
2840 Handle method_type(THREAD, (oop) result.get_jobject());
2841
2842 if (can_be_cached) {
2843 // We can cache this MethodType inside the JVM.
2844 MutexLocker ml(THREAD, SystemDictionary_lock);
2845 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2846 if (spe == NULL)
2847 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2848 if (spe->method_type() == NULL) {
2849 spe->set_method_type(method_type());
2850 }
2851 }
2852
2853 // report back to the caller with the MethodType
2854 return method_type;
2855 }
2856
2857 Handle SystemDictionary::find_field_handle_type(Symbol* signature,
2858 Klass* accessing_klass,
2859 TRAPS) {
2860 Handle empty;
2861 ResourceMark rm(THREAD);
2862 SignatureStream ss(signature, /*is_method=*/ false);
2863 if (!ss.is_done()) {
2864 Handle class_loader, protection_domain;
2865 if (accessing_klass != NULL) {
2866 class_loader = Handle(THREAD, accessing_klass->class_loader());
2867 protection_domain = Handle(THREAD, accessing_klass->protection_domain());
2868 }
2869 oop mirror = ss.as_java_mirror(class_loader, protection_domain, SignatureStream::NCDFError, CHECK_(empty));
2870 ss.next();
2871 if (ss.is_done()) {
2872 return Handle(THREAD, mirror);
2873 }
2874 }
2875 return empty;
2876 }
2877
2878 // Ask Java code to find or construct a method handle constant.
2879 Handle SystemDictionary::link_method_handle_constant(Klass* caller,
2880 int ref_kind, //e.g., JVM_REF_invokeVirtual
2881 Klass* callee,
2882 Symbol* name,
2883 Symbol* signature,
2884 TRAPS) {
2885 Handle empty;
2886 if (caller == NULL) {
2887 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2888 }
2889 Handle name_str = java_lang_String::create_from_symbol(name, CHECK_(empty));
2890 Handle signature_str = java_lang_String::create_from_symbol(signature, CHECK_(empty));
2891
2892 // Put symbolic info from the MH constant into freshly created MemberName and resolve it.
2893 Handle mname = MemberName_klass()->allocate_instance_handle(CHECK_(empty));
2894 java_lang_invoke_MemberName::set_clazz(mname(), callee->java_mirror());
2895 java_lang_invoke_MemberName::set_name (mname(), name_str());
2896 java_lang_invoke_MemberName::set_type (mname(), signature_str());
2897 java_lang_invoke_MemberName::set_flags(mname(), MethodHandles::ref_kind_to_flags(ref_kind));
2898
2899 if (ref_kind == JVM_REF_invokeVirtual &&
2900 MethodHandles::is_signature_polymorphic_public_name(callee, name)) {
2901 // Skip resolution for public signature polymorphic methods such as
2902 // j.l.i.MethodHandle.invoke()/invokeExact() and those on VarHandle
2903 // They require appendix argument which MemberName resolution doesn't handle.
2904 // There's special logic on JDK side to handle them
2905 // (see MethodHandles.linkMethodHandleConstant() and MethodHandles.findVirtualForMH()).
2906 } else {
2907 MethodHandles::resolve_MemberName(mname, caller, /*speculative_resolve*/false, CHECK_(empty));
2908 }
2909
2910 // After method/field resolution succeeded, it's safe to resolve MH signature as well.
2911 Handle type = MethodHandles::resolve_MemberName_type(mname, caller, CHECK_(empty));
2912
2913 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2914 JavaCallArguments args;
2915 args.push_oop(Handle(THREAD, caller->java_mirror())); // the referring class
2916 args.push_int(ref_kind);
2917 args.push_oop(Handle(THREAD, callee->java_mirror())); // the target class
2918 args.push_oop(name_str);
2919 args.push_oop(type);
2920 JavaValue result(T_OBJECT);
2921 JavaCalls::call_static(&result,
2922 SystemDictionary::MethodHandleNatives_klass(),
2923 vmSymbols::linkMethodHandleConstant_name(),
2924 vmSymbols::linkMethodHandleConstant_signature(),
2925 &args, CHECK_(empty));
2926 return Handle(THREAD, (oop) result.get_jobject());
2927 }
2928
2929 // Ask Java to run a bootstrap method, in order to create a dynamic call site
2930 // while linking an invokedynamic op, or compute a constant for Dynamic_info CP entry
2931 // with linkage results being stored back into the bootstrap specifier.
2932 void SystemDictionary::invoke_bootstrap_method(BootstrapInfo& bootstrap_specifier, TRAPS) {
2933 // Resolve the bootstrap specifier, its name, type, and static arguments
2934 bootstrap_specifier.resolve_bsm(CHECK);
2935
2936 // This should not happen. JDK code should take care of that.
2937 if (bootstrap_specifier.caller() == NULL || bootstrap_specifier.type_arg().is_null()) {
2938 THROW_MSG(vmSymbols::java_lang_InternalError(), "Invalid bootstrap method invocation with no caller or type argument");
2939 }
2940
2941 bool is_indy = bootstrap_specifier.is_method_call();
2942 objArrayHandle appendix_box;
2943 if (is_indy) {
2944 // Some method calls may require an appendix argument. Arrange to receive it.
2945 appendix_box = oopFactory::new_objArray_handle(SystemDictionary::Object_klass(), 1, CHECK);
2946 assert(appendix_box->obj_at(0) == NULL, "");
2947 }
2948
2949 // call condy: java.lang.invoke.MethodHandleNatives::linkDynamicConstant(caller, condy_index, bsm, type, info)
2950 // indy: java.lang.invoke.MethodHandleNatives::linkCallSite(caller, indy_index, bsm, name, mtype, info, &appendix)
2951 JavaCallArguments args;
2952 args.push_oop(Handle(THREAD, bootstrap_specifier.caller_mirror()));
2953 args.push_int(bootstrap_specifier.bss_index());
2954 args.push_oop(bootstrap_specifier.bsm());
2955 args.push_oop(bootstrap_specifier.name_arg());
2956 args.push_oop(bootstrap_specifier.type_arg());
2957 args.push_oop(bootstrap_specifier.arg_values());
2958 if (is_indy) {
2959 args.push_oop(appendix_box);
2960 }
2961 JavaValue result(T_OBJECT);
2962 JavaCalls::call_static(&result,
2963 SystemDictionary::MethodHandleNatives_klass(),
2964 is_indy ? vmSymbols::linkCallSite_name() : vmSymbols::linkDynamicConstant_name(),
2965 is_indy ? vmSymbols::linkCallSite_signature() : vmSymbols::linkDynamicConstant_signature(),
2966 &args, CHECK);
2967
2968 Handle value(THREAD, (oop) result.get_jobject());
2969 if (is_indy) {
2970 Handle appendix;
2971 Method* method = unpack_method_and_appendix(value,
2972 bootstrap_specifier.caller(),
2973 appendix_box,
2974 &appendix, CHECK);
2975 methodHandle mh(THREAD, method);
2976 bootstrap_specifier.set_resolved_method(mh, appendix);
2977 } else {
2978 bootstrap_specifier.set_resolved_value(value);
2979 }
2980
2981 // sanity check
2982 assert(bootstrap_specifier.is_resolved() ||
2983 (bootstrap_specifier.is_method_call() &&
2984 bootstrap_specifier.resolved_method().not_null()), "bootstrap method call failed");
2985 }
2986
2987 // Protection domain cache table handling
2988
2989 ProtectionDomainCacheEntry* SystemDictionary::cache_get(Handle protection_domain) {
2990 return _pd_cache_table->get(protection_domain);
2991 }
2992
2993 // ----------------------------------------------------------------------------
2994
2995 void SystemDictionary::print_on(outputStream *st) {
2996 CDS_ONLY(SystemDictionaryShared::print_on(st));
2997 GCMutexLocker mu(SystemDictionary_lock);
2998
2999 ClassLoaderDataGraph::print_dictionary(st);
3000
3001 // Placeholders
3002 placeholders()->print_on(st);
3003 st->cr();
3004
3005 // loader constraints - print under SD_lock
3006 constraints()->print_on(st);
3007 st->cr();
3008
3009 _pd_cache_table->print_on(st);
3010 st->cr();
3011 }
3012
3013 void SystemDictionary::print() { print_on(tty); }
3014
3015 void SystemDictionary::verify() {
3016 guarantee(constraints() != NULL,
3017 "Verify of loader constraints failed");
3018 guarantee(placeholders()->number_of_entries() >= 0,
3019 "Verify of placeholders failed");
3020
3021 GCMutexLocker mu(SystemDictionary_lock);
3022
3023 // Verify dictionary
3024 ClassLoaderDataGraph::verify_dictionary();
3025
3026 placeholders()->verify();
3027
3028 // Verify constraint table
3029 guarantee(constraints() != NULL, "Verify of loader constraints failed");
3030 constraints()->verify(placeholders());
3031
3032 _pd_cache_table->verify();
3033 }
3034
3035 void SystemDictionary::dump(outputStream *st, bool verbose) {
3036 assert_locked_or_safepoint(SystemDictionary_lock);
3037 if (verbose) {
3038 print_on(st);
3039 } else {
3040 CDS_ONLY(SystemDictionaryShared::print_table_statistics(st));
3041 ClassLoaderDataGraph::print_table_statistics(st);
3042 placeholders()->print_table_statistics(st, "Placeholder Table");
3043 constraints()->print_table_statistics(st, "LoaderConstraints Table");
3044 pd_cache_table()->print_table_statistics(st, "ProtectionDomainCache Table");
3045 }
3046 }
3047
3048 TableStatistics SystemDictionary::placeholders_statistics() {
3049 MutexLocker ml(SystemDictionary_lock);
3050 return placeholders()->statistics_calculate();
3051 }
3052
3053 TableStatistics SystemDictionary::loader_constraints_statistics() {
3054 MutexLocker ml(SystemDictionary_lock);
3055 return constraints()->statistics_calculate();
3056 }
3057
3058 TableStatistics SystemDictionary::protection_domain_cache_statistics() {
3059 MutexLocker ml(SystemDictionary_lock);
3060 return pd_cache_table()->statistics_calculate();
3061 }
3062
3063 // Utility for dumping dictionaries.
3064 SystemDictionaryDCmd::SystemDictionaryDCmd(outputStream* output, bool heap) :
3065 DCmdWithParser(output, heap),
3066 _verbose("-verbose", "Dump the content of each dictionary entry for all class loaders",
3067 "BOOLEAN", false, "false") {
3068 _dcmdparser.add_dcmd_option(&_verbose);
3069 }
3070
3071 void SystemDictionaryDCmd::execute(DCmdSource source, TRAPS) {
3072 VM_DumpHashtable dumper(output(), VM_DumpHashtable::DumpSysDict,
3073 _verbose.value());
3074 VMThread::execute(&dumper);
3075 }
3076
3077 int SystemDictionaryDCmd::num_arguments() {
3078 ResourceMark rm;
3079 SystemDictionaryDCmd* dcmd = new SystemDictionaryDCmd(NULL, false);
3080 if (dcmd != NULL) {
3081 DCmdMark mark(dcmd);
3082 return dcmd->_dcmdparser.num_arguments();
3083 } else {
3084 return 0;
3085 }
3086 }