Fri, 14 Feb 2020 17:13:16 +0100
8238589: Necessary code cleanup in JFR for JDK8u
Reviewed-by: shade, apetushkov
1 /*
2 * Copyright (c) 1997, 2018, 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 */
25 #include "precompiled.hpp"
26 #include "classfile/classLoaderData.inline.hpp"
27 #include "classfile/dictionary.hpp"
28 #include "classfile/javaClasses.hpp"
29 #include "classfile/loaderConstraints.hpp"
30 #include "classfile/placeholders.hpp"
31 #include "classfile/resolutionErrors.hpp"
32 #include "classfile/systemDictionary.hpp"
33 #if INCLUDE_CDS
34 #include "classfile/sharedClassUtil.hpp"
35 #include "classfile/systemDictionaryShared.hpp"
36 #endif
37 #include "classfile/vmSymbols.hpp"
38 #include "compiler/compileBroker.hpp"
39 #include "interpreter/bytecodeStream.hpp"
40 #include "interpreter/interpreter.hpp"
41 #include "jfr/jfrEvents.hpp"
42 #include "jfr/jni/jfrUpcalls.hpp"
43 #include "memory/filemap.hpp"
44 #include "memory/gcLocker.hpp"
45 #include "memory/oopFactory.hpp"
46 #include "oops/instanceKlass.hpp"
47 #include "oops/instanceRefKlass.hpp"
48 #include "oops/klass.inline.hpp"
49 #include "oops/methodData.hpp"
50 #include "oops/objArrayKlass.hpp"
51 #include "oops/oop.inline.hpp"
52 #include "oops/oop.inline2.hpp"
53 #include "oops/typeArrayKlass.hpp"
54 #include "prims/jvmtiEnvBase.hpp"
55 #include "prims/methodHandles.hpp"
56 #include "runtime/arguments.hpp"
57 #include "runtime/biasedLocking.hpp"
58 #include "runtime/fieldType.hpp"
59 #include "runtime/handles.inline.hpp"
60 #include "runtime/java.hpp"
61 #include "runtime/javaCalls.hpp"
62 #include "runtime/mutexLocker.hpp"
63 #include "runtime/orderAccess.inline.hpp"
64 #include "runtime/signature.hpp"
65 #include "services/classLoadingService.hpp"
66 #include "services/threadService.hpp"
67 #include "utilities/macros.hpp"
68 #include "utilities/ticks.hpp"
70 Dictionary* SystemDictionary::_dictionary = NULL;
71 PlaceholderTable* SystemDictionary::_placeholders = NULL;
72 Dictionary* SystemDictionary::_shared_dictionary = NULL;
73 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
74 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
75 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
78 int SystemDictionary::_number_of_modifications = 0;
79 int SystemDictionary::_sdgeneration = 0;
80 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
81 20201,40423,99991};
83 oop SystemDictionary::_system_loader_lock_obj = NULL;
85 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
86 = { NULL /*, NULL...*/ };
88 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
90 oop SystemDictionary::_java_system_loader = NULL;
92 bool SystemDictionary::_has_loadClassInternal = false;
93 bool SystemDictionary::_has_checkPackageAccess = false;
95 // lazily initialized klass variables
96 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
98 #if INCLUDE_JFR
99 static const Symbol* jfr_event_handler_proxy = NULL;
100 #endif // INCLUDE_JFR
102 // ----------------------------------------------------------------------------
103 // Java-level SystemLoader
105 oop SystemDictionary::java_system_loader() {
106 return _java_system_loader;
107 }
109 void SystemDictionary::compute_java_system_loader(TRAPS) {
110 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
111 JavaValue result(T_OBJECT);
112 JavaCalls::call_static(&result,
113 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
114 vmSymbols::getSystemClassLoader_name(),
115 vmSymbols::void_classloader_signature(),
116 CHECK);
118 _java_system_loader = (oop)result.get_jobject();
120 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
121 }
124 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
125 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
126 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
127 }
129 // ----------------------------------------------------------------------------
130 // debugging
132 #ifdef ASSERT
134 // return true if class_name contains no '.' (internal format is '/')
135 bool SystemDictionary::is_internal_format(Symbol* class_name) {
136 if (class_name != NULL) {
137 ResourceMark rm;
138 char* name = class_name->as_C_string();
139 return strchr(name, '.') == NULL;
140 } else {
141 return true;
142 }
143 }
145 #endif
146 #if INCLUDE_JFR
147 #include "jfr/jfr.hpp"
148 #endif
150 // ----------------------------------------------------------------------------
151 // Parallel class loading check
153 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
154 if (UnsyncloadClass || class_loader.is_null()) return true;
155 if (AlwaysLockClassLoader) return false;
156 return java_lang_ClassLoader::parallelCapable(class_loader());
157 }
158 // ----------------------------------------------------------------------------
159 // ParallelDefineClass flag does not apply to bootclass loader
160 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
161 if (class_loader.is_null()) return false;
162 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
163 return true;
164 }
165 return false;
166 }
168 /**
169 * Returns true if the passed class loader is the extension class loader.
170 */
171 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
172 if (class_loader.is_null()) {
173 return false;
174 }
175 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
176 }
178 // ----------------------------------------------------------------------------
179 // Resolving of classes
181 // Forwards to resolve_or_null
183 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
184 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
185 if (HAS_PENDING_EXCEPTION || klass == NULL) {
186 KlassHandle k_h(THREAD, klass);
187 // can return a null klass
188 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
189 }
190 return klass;
191 }
193 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
194 if (HAS_PENDING_EXCEPTION) {
195 // If we have a pending exception we forward it to the caller, unless throw_error is true,
196 // in which case we have to check whether the pending exception is a ClassNotFoundException,
197 // and if so convert it to a NoClassDefFoundError
198 // And chain the original ClassNotFoundException
199 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
200 ResourceMark rm(THREAD);
201 assert(klass_h() == NULL, "Should not have result with exception pending");
202 Handle e(THREAD, PENDING_EXCEPTION);
203 CLEAR_PENDING_EXCEPTION;
204 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
205 } else {
206 return NULL;
207 }
208 }
209 // Class not found, throw appropriate error or exception depending on value of throw_error
210 if (klass_h() == NULL) {
211 ResourceMark rm(THREAD);
212 if (throw_error) {
213 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
214 } else {
215 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
216 }
217 }
218 return (Klass*)klass_h();
219 }
222 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
223 bool throw_error, TRAPS)
224 {
225 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
226 }
229 // Forwards to resolve_instance_class_or_null
231 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
232 assert(!THREAD->is_Compiler_thread(),
233 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
234 class_name->as_C_string(),
235 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
236 if (FieldType::is_array(class_name)) {
237 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
238 } else if (FieldType::is_obj(class_name)) {
239 ResourceMark rm(THREAD);
240 // Ignore wrapping L and ;.
241 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
242 class_name->utf8_length() - 2, CHECK_NULL);
243 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
244 } else {
245 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
246 }
247 }
249 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
250 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
251 }
253 // Forwards to resolve_instance_class_or_null
255 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
256 Handle class_loader,
257 Handle protection_domain,
258 TRAPS) {
259 assert(FieldType::is_array(class_name), "must be array");
260 Klass* k = NULL;
261 FieldArrayInfo fd;
262 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
263 // of this call
264 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
265 if (t == T_OBJECT) {
266 // naked oop "k" is OK here -- we assign back into it
267 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
268 class_loader,
269 protection_domain,
270 CHECK_NULL);
271 if (k != NULL) {
272 k = k->array_klass(fd.dimension(), CHECK_NULL);
273 }
274 } else {
275 k = Universe::typeArrayKlassObj(t);
276 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
277 }
278 return k;
279 }
282 // Must be called for any super-class or super-interface resolution
283 // during class definition to allow class circularity checking
284 // super-interface callers:
285 // parse_interfaces - for defineClass & jvmtiRedefineClasses
286 // super-class callers:
287 // ClassFileParser - for defineClass & jvmtiRedefineClasses
288 // load_shared_class - while loading a class from shared archive
289 // resolve_instance_class_or_null:
290 // via: handle_parallel_super_load
291 // when resolving a class that has an existing placeholder with
292 // a saved superclass [i.e. a defineClass is currently in progress]
293 // if another thread is trying to resolve the class, it must do
294 // super-class checks on its own thread to catch class circularity
295 // This last call is critical in class circularity checking for cases
296 // where classloading is delegated to different threads and the
297 // classloader lock is released.
298 // Take the case: Base->Super->Base
299 // 1. If thread T1 tries to do a defineClass of class Base
300 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
301 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
302 // so it tries to load Super
303 // 3. If we load the class internally, or user classloader uses same thread
304 // loadClassFromxxx or defineClass via parseClassFile Super ...
305 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
306 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
307 // 3.4 calls resolve_super_or_fail Base
308 // 3.5 finds T1,Base -> throws class circularity
309 //OR 4. If T2 tries to resolve Super via defineClass Super ...
310 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
311 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
312 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
313 // 4.4 finds T2, Super -> throws class circularity
314 // Must be called, even if superclass is null, since this is
315 // where the placeholder entry is created which claims this
316 // thread is loading this class/classloader.
317 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
318 Symbol* class_name,
319 Handle class_loader,
320 Handle protection_domain,
321 bool is_superclass,
322 TRAPS) {
323 // Double-check, if child class is already loaded, just return super-class,interface
324 // Don't add a placedholder if already loaded, i.e. already in system dictionary
325 // Make sure there's a placeholder for the *child* before resolving.
326 // Used as a claim that this thread is currently loading superclass/classloader
327 // Used here for ClassCircularity checks and also for heap verification
328 // (every InstanceKlass in the heap needs to be in the system dictionary
329 // or have a placeholder).
330 // Must check ClassCircularity before checking if super class is already loaded
331 //
332 // We might not already have a placeholder if this child_name was
333 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
334 // the name of the class might not be known until the stream is actually
335 // parsed.
336 // Bugs 4643874, 4715493
337 // compute_hash can have a safepoint
339 ClassLoaderData* loader_data = class_loader_data(class_loader);
340 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
341 int d_index = dictionary()->hash_to_index(d_hash);
342 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
343 int p_index = placeholders()->hash_to_index(p_hash);
344 // can't throw error holding a lock
345 bool child_already_loaded = false;
346 bool throw_circularity_error = false;
347 {
348 MutexLocker mu(SystemDictionary_lock, THREAD);
349 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
350 Klass* quicksuperk;
351 // to support // loading: if child done loading, just return superclass
352 // if class_name, & class_loader don't match:
353 // if initial define, SD update will give LinkageError
354 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
355 // so we don't throw an exception here.
356 // see: nsk redefclass014 & java.lang.instrument Instrument032
357 if ((childk != NULL ) && (is_superclass) &&
358 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
360 ((quicksuperk->name() == class_name) &&
361 (quicksuperk->class_loader() == class_loader()))) {
362 return quicksuperk;
363 } else {
364 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
365 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
366 throw_circularity_error = true;
367 }
368 }
369 if (!throw_circularity_error) {
370 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
371 }
372 }
373 if (throw_circularity_error) {
374 ResourceMark rm(THREAD);
375 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
376 }
378 // java.lang.Object should have been found above
379 assert(class_name != NULL, "null super class for resolving");
380 // Resolve the super class or interface, check results on return
381 Klass* superk = SystemDictionary::resolve_or_null(class_name,
382 class_loader,
383 protection_domain,
384 THREAD);
386 KlassHandle superk_h(THREAD, superk);
388 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
389 // It is no longer necessary to keep the placeholder table alive until update_dictionary
390 // or error. GC used to walk the placeholder table as strong roots.
391 // The instanceKlass is kept alive because the class loader is on the stack,
392 // which keeps the loader_data alive, as well as all instanceKlasses in
393 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
394 {
395 MutexLocker mu(SystemDictionary_lock, THREAD);
396 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
397 SystemDictionary_lock->notify_all();
398 }
399 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
400 // can null superk
401 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
402 }
404 return superk_h();
405 }
407 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
408 Handle class_loader,
409 Handle protection_domain,
410 TRAPS) {
411 if(!has_checkPackageAccess()) return;
413 // Now we have to call back to java to check if the initating class has access
414 JavaValue result(T_VOID);
415 if (TraceProtectionDomainVerification) {
416 // Print out trace information
417 tty->print_cr("Checking package access");
418 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
419 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
420 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
421 }
423 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
424 JavaCalls::call_special(&result,
425 class_loader,
426 system_loader,
427 vmSymbols::checkPackageAccess_name(),
428 vmSymbols::class_protectiondomain_signature(),
429 Handle(THREAD, klass->java_mirror()),
430 protection_domain,
431 THREAD);
433 if (TraceProtectionDomainVerification) {
434 if (HAS_PENDING_EXCEPTION) {
435 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
436 } else {
437 tty->print_cr(" -> granted");
438 }
439 tty->cr();
440 }
442 if (HAS_PENDING_EXCEPTION) return;
444 // If no exception has been thrown, we have validated the protection domain
445 // Insert the protection domain of the initiating class into the set.
446 {
447 // We recalculate the entry here -- we've called out to java since
448 // the last time it was calculated.
449 ClassLoaderData* loader_data = class_loader_data(class_loader);
451 Symbol* kn = klass->name();
452 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
453 int d_index = dictionary()->hash_to_index(d_hash);
455 MutexLocker mu(SystemDictionary_lock, THREAD);
456 {
457 // Note that we have an entry, and entries can be deleted only during GC,
458 // so we cannot allow GC to occur while we're holding this entry.
460 // We're using a No_Safepoint_Verifier to catch any place where we
461 // might potentially do a GC at all.
462 // Dictionary::do_unloading() asserts that classes in SD are only
463 // unloaded at a safepoint. Anonymous classes are not in SD.
464 No_Safepoint_Verifier nosafepoint;
465 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
466 protection_domain, THREAD);
467 }
468 }
469 }
471 // We only get here if this thread finds that another thread
472 // has already claimed the placeholder token for the current operation,
473 // but that other thread either never owned or gave up the
474 // object lock
475 // Waits on SystemDictionary_lock to indicate placeholder table updated
476 // On return, caller must recheck placeholder table state
477 //
478 // We only get here if
479 // 1) custom classLoader, i.e. not bootstrap classloader
480 // 2) UnsyncloadClass not set
481 // 3) custom classLoader has broken the class loader objectLock
482 // so another thread got here in parallel
483 //
484 // lockObject must be held.
485 // Complicated dance due to lock ordering:
486 // Must first release the classloader object lock to
487 // allow initial definer to complete the class definition
488 // and to avoid deadlock
489 // Reclaim classloader lock object with same original recursion count
490 // Must release SystemDictionary_lock after notify, since
491 // class loader lock must be claimed before SystemDictionary_lock
492 // to prevent deadlocks
493 //
494 // The notify allows applications that did an untimed wait() on
495 // the classloader object lock to not hang.
496 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
497 assert_lock_strong(SystemDictionary_lock);
499 bool calledholdinglock
500 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
501 assert(calledholdinglock,"must hold lock for notify");
502 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
503 ObjectSynchronizer::notifyall(lockObject, THREAD);
504 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
505 SystemDictionary_lock->wait();
506 SystemDictionary_lock->unlock();
507 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
508 SystemDictionary_lock->lock();
509 }
511 // If the class in is in the placeholder table, class loading is in progress
512 // For cases where the application changes threads to load classes, it
513 // is critical to ClassCircularity detection that we try loading
514 // the superclass on the same thread internally, so we do parallel
515 // super class loading here.
516 // This also is critical in cases where the original thread gets stalled
517 // even in non-circularity situations.
518 // Note: must call resolve_super_or_fail even if null super -
519 // to force placeholder entry creation for this class for circularity detection
520 // Caller must check for pending exception
521 // Returns non-null Klass* if other thread has completed load
522 // and we are done,
523 // If return null Klass* and no pending exception, the caller must load the class
524 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
525 Symbol* name, Symbol* superclassname, Handle class_loader,
526 Handle protection_domain, Handle lockObject, TRAPS) {
528 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
529 ClassLoaderData* loader_data = class_loader_data(class_loader);
530 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
531 int d_index = dictionary()->hash_to_index(d_hash);
532 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
533 int p_index = placeholders()->hash_to_index(p_hash);
535 // superk is not used, resolve_super called for circularity check only
536 // This code is reached in two situations. One if this thread
537 // is loading the same class twice (e.g. ClassCircularity, or
538 // java.lang.instrument).
539 // The second is if another thread started the resolve_super first
540 // and has not yet finished.
541 // In both cases the original caller will clean up the placeholder
542 // entry on error.
543 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
544 superclassname,
545 class_loader,
546 protection_domain,
547 true,
548 CHECK_(nh));
550 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
551 // Serial class loaders and bootstrap classloader do wait for superclass loads
552 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
553 MutexLocker mu(SystemDictionary_lock, THREAD);
554 // Check if classloading completed while we were loading superclass or waiting
555 Klass* check = find_class(d_index, d_hash, name, loader_data);
556 if (check != NULL) {
557 // Klass is already loaded, so just return it
558 return(instanceKlassHandle(THREAD, check));
559 } else {
560 return nh;
561 }
562 }
564 // must loop to both handle other placeholder updates
565 // and spurious notifications
566 bool super_load_in_progress = true;
567 PlaceholderEntry* placeholder;
568 while (super_load_in_progress) {
569 MutexLocker mu(SystemDictionary_lock, THREAD);
570 // Check if classloading completed while we were loading superclass or waiting
571 Klass* check = find_class(d_index, d_hash, name, loader_data);
572 if (check != NULL) {
573 // Klass is already loaded, so just return it
574 return(instanceKlassHandle(THREAD, check));
575 } else {
576 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
577 if (placeholder && placeholder->super_load_in_progress() ){
578 // Before UnsyncloadClass:
579 // We only get here if the application has released the
580 // classloader lock when another thread was in the middle of loading a
581 // superclass/superinterface for this class, and now
582 // this thread is also trying to load this class.
583 // To minimize surprises, the first thread that started to
584 // load a class should be the one to complete the loading
585 // with the classfile it initially expected.
586 // This logic has the current thread wait once it has done
587 // all the superclass/superinterface loading it can, until
588 // the original thread completes the class loading or fails
589 // If it completes we will use the resulting InstanceKlass
590 // which we will find below in the systemDictionary.
591 // We also get here for parallel bootstrap classloader
592 if (class_loader.is_null()) {
593 SystemDictionary_lock->wait();
594 } else {
595 double_lock_wait(lockObject, THREAD);
596 }
597 } else {
598 // If not in SD and not in PH, other thread's load must have failed
599 super_load_in_progress = false;
600 }
601 }
602 }
603 return (nh);
604 }
606 // utility function for class load event
607 static void post_class_load_event(EventClassLoad &event,
608 instanceKlassHandle k,
609 Handle initiating_loader) {
610 #if INCLUDE_JFR
611 if (event.should_commit()) {
612 event.set_loadedClass(k());
613 event.set_definingClassLoader(k->class_loader_data());
614 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
615 event.set_initiatingClassLoader(class_loader != NULL ?
616 ClassLoaderData::class_loader_data_or_null(class_loader) :
617 (ClassLoaderData*)NULL);
618 event.commit();
619 }
620 #endif
621 }
623 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
624 Handle class_loader,
625 Handle protection_domain,
626 TRAPS) {
627 assert(name != NULL && !FieldType::is_array(name) &&
628 !FieldType::is_obj(name), "invalid class name");
630 EventClassLoad class_load_start_event;
632 // UseNewReflection
633 // Fix for 4474172; see evaluation for more details
634 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
635 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
637 // Do lookup to see if class already exist and the protection domain
638 // has the right access
639 // This call uses find which checks protection domain already matches
640 // All subsequent calls use find_class, and set has_loaded_class so that
641 // before we return a result we call out to java to check for valid protection domain
642 // to allow returning the Klass* and add it to the pd_set if it is valid
643 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
644 int d_index = dictionary()->hash_to_index(d_hash);
645 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
646 protection_domain, THREAD);
647 if (probe != NULL) return probe;
650 // Non-bootstrap class loaders will call out to class loader and
651 // define via jvm/jni_DefineClass which will acquire the
652 // class loader object lock to protect against multiple threads
653 // defining the class in parallel by accident.
654 // This lock must be acquired here so the waiter will find
655 // any successful result in the SystemDictionary and not attempt
656 // the define
657 // ParallelCapable Classloaders and the bootstrap classloader,
658 // or all classloaders with UnsyncloadClass do not acquire lock here
659 bool DoObjectLock = true;
660 if (is_parallelCapable(class_loader)) {
661 DoObjectLock = false;
662 }
664 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
665 int p_index = placeholders()->hash_to_index(p_hash);
667 // Class is not in SystemDictionary so we have to do loading.
668 // Make sure we are synchronized on the class loader before we proceed
669 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
670 check_loader_lock_contention(lockObject, THREAD);
671 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
673 // Check again (after locking) if class already exist in SystemDictionary
674 bool class_has_been_loaded = false;
675 bool super_load_in_progress = false;
676 bool havesupername = false;
677 instanceKlassHandle k;
678 PlaceholderEntry* placeholder;
679 Symbol* superclassname = NULL;
681 {
682 MutexLocker mu(SystemDictionary_lock, THREAD);
683 Klass* check = find_class(d_index, d_hash, name, loader_data);
684 if (check != NULL) {
685 // Klass is already loaded, so just return it
686 class_has_been_loaded = true;
687 k = instanceKlassHandle(THREAD, check);
688 } else {
689 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
690 if (placeholder && placeholder->super_load_in_progress()) {
691 super_load_in_progress = true;
692 if (placeholder->havesupername() == true) {
693 superclassname = placeholder->supername();
694 havesupername = true;
695 }
696 }
697 }
698 }
700 // If the class is in the placeholder table, class loading is in progress
701 if (super_load_in_progress && havesupername==true) {
702 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
703 class_loader, protection_domain, lockObject, THREAD);
704 if (HAS_PENDING_EXCEPTION) {
705 return NULL;
706 }
707 if (!k.is_null()) {
708 class_has_been_loaded = true;
709 }
710 }
712 bool throw_circularity_error = false;
713 if (!class_has_been_loaded) {
714 bool load_instance_added = false;
716 // add placeholder entry to record loading instance class
717 // Five cases:
718 // All cases need to prevent modifying bootclasssearchpath
719 // in parallel with a classload of same classname
720 // Redefineclasses uses existence of the placeholder for the duration
721 // of the class load to prevent concurrent redefinition of not completely
722 // defined classes.
723 // case 1. traditional classloaders that rely on the classloader object lock
724 // - no other need for LOAD_INSTANCE
725 // case 2. traditional classloaders that break the classloader object lock
726 // as a deadlock workaround. Detection of this case requires that
727 // this check is done while holding the classloader object lock,
728 // and that lock is still held when calling classloader's loadClass.
729 // For these classloaders, we ensure that the first requestor
730 // completes the load and other requestors wait for completion.
731 // case 3. UnsyncloadClass - don't use objectLocker
732 // With this flag, we allow parallel classloading of a
733 // class/classloader pair
734 // case4. Bootstrap classloader - don't own objectLocker
735 // This classloader supports parallelism at the classloader level,
736 // but only allows a single load of a class/classloader pair.
737 // No performance benefit and no deadlock issues.
738 // case 5. parallelCapable user level classloaders - without objectLocker
739 // Allow parallel classloading of a class/classloader pair
741 {
742 MutexLocker mu(SystemDictionary_lock, THREAD);
743 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
744 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
745 if (oldprobe) {
746 // only need check_seen_thread once, not on each loop
747 // 6341374 java/lang/Instrument with -Xcomp
748 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
749 throw_circularity_error = true;
750 } else {
751 // case 1: traditional: should never see load_in_progress.
752 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
754 // case 4: bootstrap classloader: prevent futile classloading,
755 // wait on first requestor
756 if (class_loader.is_null()) {
757 SystemDictionary_lock->wait();
758 } else {
759 // case 2: traditional with broken classloader lock. wait on first
760 // requestor.
761 double_lock_wait(lockObject, THREAD);
762 }
763 // Check if classloading completed while we were waiting
764 Klass* check = find_class(d_index, d_hash, name, loader_data);
765 if (check != NULL) {
766 // Klass is already loaded, so just return it
767 k = instanceKlassHandle(THREAD, check);
768 class_has_been_loaded = true;
769 }
770 // check if other thread failed to load and cleaned up
771 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
772 }
773 }
774 }
775 }
776 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
777 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
778 // LOAD_INSTANCE in parallel
780 if (!throw_circularity_error && !class_has_been_loaded) {
781 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
782 load_instance_added = true;
783 // For class loaders that do not acquire the classloader object lock,
784 // if they did not catch another thread holding LOAD_INSTANCE,
785 // need a check analogous to the acquire ObjectLocker/find_class
786 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
787 // one final check if the load has already completed
788 // class loaders holding the ObjectLock shouldn't find the class here
789 Klass* check = find_class(d_index, d_hash, name, loader_data);
790 if (check != NULL) {
791 // Klass is already loaded, so return it after checking/adding protection domain
792 k = instanceKlassHandle(THREAD, check);
793 class_has_been_loaded = true;
794 }
795 }
796 }
798 // must throw error outside of owning lock
799 if (throw_circularity_error) {
800 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
801 ResourceMark rm(THREAD);
802 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
803 }
805 if (!class_has_been_loaded) {
807 // Do actual loading
808 k = load_instance_class(name, class_loader, THREAD);
810 // For UnsyncloadClass only
811 // If they got a linkageError, check if a parallel class load succeeded.
812 // If it did, then for bytecode resolution the specification requires
813 // that we return the same result we did for the other thread, i.e. the
814 // successfully loaded InstanceKlass
815 // Should not get here for classloaders that support parallelism
816 // with the new cleaner mechanism, even with AllowParallelDefineClass
817 // Bootstrap goes through here to allow for an extra guarantee check
818 if (UnsyncloadClass || (class_loader.is_null())) {
819 if (k.is_null() && HAS_PENDING_EXCEPTION
820 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
821 MutexLocker mu(SystemDictionary_lock, THREAD);
822 Klass* check = find_class(d_index, d_hash, name, loader_data);
823 if (check != NULL) {
824 // Klass is already loaded, so just use it
825 k = instanceKlassHandle(THREAD, check);
826 CLEAR_PENDING_EXCEPTION;
827 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
828 }
829 }
830 }
832 // If everything was OK (no exceptions, no null return value), and
833 // class_loader is NOT the defining loader, do a little more bookkeeping.
834 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
835 k->class_loader() != class_loader()) {
837 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
839 // Need to check for a PENDING_EXCEPTION again; check_constraints
840 // can throw but we may have to remove entry from the placeholder table below.
841 if (!HAS_PENDING_EXCEPTION) {
842 // Record dependency for non-parent delegation.
843 // This recording keeps the defining class loader of the klass (k) found
844 // from being unloaded while the initiating class loader is loaded
845 // even if the reference to the defining class loader is dropped
846 // before references to the initiating class loader.
847 loader_data->record_dependency(k(), THREAD);
848 }
850 if (!HAS_PENDING_EXCEPTION) {
851 { // Grabbing the Compile_lock prevents systemDictionary updates
852 // during compilations.
853 MutexLocker mu(Compile_lock, THREAD);
854 update_dictionary(d_index, d_hash, p_index, p_hash,
855 k, class_loader, THREAD);
856 }
858 if (JvmtiExport::should_post_class_load()) {
859 Thread *thread = THREAD;
860 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
861 JvmtiExport::post_class_load((JavaThread *) thread, k());
862 }
863 }
864 }
865 } // load_instance_class loop
867 if (load_instance_added == true) {
868 // clean up placeholder entries for LOAD_INSTANCE success or error
869 // This brackets the SystemDictionary updates for both defining
870 // and initiating loaders
871 MutexLocker mu(SystemDictionary_lock, THREAD);
872 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
873 SystemDictionary_lock->notify_all();
874 }
875 }
877 if (HAS_PENDING_EXCEPTION || k.is_null()) {
878 return NULL;
879 }
881 post_class_load_event(class_load_start_event, k, class_loader);
883 #ifdef ASSERT
884 {
885 ClassLoaderData* loader_data = k->class_loader_data();
886 MutexLocker mu(SystemDictionary_lock, THREAD);
887 Klass* kk = find_class(name, loader_data);
888 assert(kk == k(), "should be present in dictionary");
889 }
890 #endif
892 // return if the protection domain in NULL
893 if (protection_domain() == NULL) return k();
895 // Check the protection domain has the right access
896 {
897 MutexLocker mu(SystemDictionary_lock, THREAD);
898 // Note that we have an entry, and entries can be deleted only during GC,
899 // so we cannot allow GC to occur while we're holding this entry.
900 // We're using a No_Safepoint_Verifier to catch any place where we
901 // might potentially do a GC at all.
902 // Dictionary::do_unloading() asserts that classes in SD are only
903 // unloaded at a safepoint. Anonymous classes are not in SD.
904 No_Safepoint_Verifier nosafepoint;
905 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
906 loader_data,
907 protection_domain)) {
908 return k();
909 }
910 }
912 // Verify protection domain. If it fails an exception is thrown
913 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
915 return k();
916 }
919 // This routine does not lock the system dictionary.
920 //
921 // Since readers don't hold a lock, we must make sure that system
922 // dictionary entries are only removed at a safepoint (when only one
923 // thread is running), and are added to in a safe way (all links must
924 // be updated in an MT-safe manner).
925 //
926 // Callers should be aware that an entry could be added just after
927 // _dictionary->bucket(index) is read here, so the caller will not see
928 // the new entry.
930 Klass* SystemDictionary::find(Symbol* class_name,
931 Handle class_loader,
932 Handle protection_domain,
933 TRAPS) {
935 // UseNewReflection
936 // The result of this call should be consistent with the result
937 // of the call to resolve_instance_class_or_null().
938 // See evaluation 6790209 and 4474172 for more details.
939 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
940 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
942 if (loader_data == NULL) {
943 // If the ClassLoaderData has not been setup,
944 // then the class loader has no entries in the dictionary.
945 return NULL;
946 }
948 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
949 int d_index = dictionary()->hash_to_index(d_hash);
951 {
952 // Note that we have an entry, and entries can be deleted only during GC,
953 // so we cannot allow GC to occur while we're holding this entry.
954 // We're using a No_Safepoint_Verifier to catch any place where we
955 // might potentially do a GC at all.
956 // Dictionary::do_unloading() asserts that classes in SD are only
957 // unloaded at a safepoint. Anonymous classes are not in SD.
958 No_Safepoint_Verifier nosafepoint;
959 return dictionary()->find(d_index, d_hash, class_name, loader_data,
960 protection_domain, THREAD);
961 }
962 }
965 // Look for a loaded instance or array klass by name. Do not do any loading.
966 // return NULL in case of error.
967 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
968 Handle class_loader,
969 Handle protection_domain,
970 TRAPS) {
971 Klass* k = NULL;
972 assert(class_name != NULL, "class name must be non NULL");
974 if (FieldType::is_array(class_name)) {
975 // The name refers to an array. Parse the name.
976 // dimension and object_key in FieldArrayInfo are assigned as a
977 // side-effect of this call
978 FieldArrayInfo fd;
979 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
980 if (t != T_OBJECT) {
981 k = Universe::typeArrayKlassObj(t);
982 } else {
983 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
984 }
985 if (k != NULL) {
986 k = k->array_klass_or_null(fd.dimension());
987 }
988 } else {
989 k = find(class_name, class_loader, protection_domain, THREAD);
990 }
991 return k;
992 }
994 // Note: this method is much like resolve_from_stream, but
995 // updates no supplemental data structures.
996 // TODO consolidate the two methods with a helper routine?
997 Klass* SystemDictionary::parse_stream(Symbol* class_name,
998 Handle class_loader,
999 Handle protection_domain,
1000 ClassFileStream* st,
1001 KlassHandle host_klass,
1002 GrowableArray<Handle>* cp_patches,
1003 TRAPS) {
1004 TempNewSymbol parsed_name = NULL;
1006 EventClassLoad class_load_start_event;
1008 ClassLoaderData* loader_data;
1009 if (host_klass.not_null()) {
1010 // Create a new CLD for anonymous class, that uses the same class loader
1011 // as the host_klass
1012 assert(EnableInvokeDynamic, "");
1013 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1014 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1015 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1016 loader_data->record_dependency(host_klass(), CHECK_NULL);
1017 } else {
1018 loader_data = ClassLoaderData::class_loader_data(class_loader());
1019 }
1021 // Parse the stream. Note that we do this even though this klass might
1022 // already be present in the SystemDictionary, otherwise we would not
1023 // throw potential ClassFormatErrors.
1024 //
1025 // Note: "name" is updated.
1027 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1028 loader_data,
1029 protection_domain,
1030 host_klass,
1031 cp_patches,
1032 parsed_name,
1033 true,
1034 THREAD);
1037 if (host_klass.not_null() && k.not_null()) {
1038 assert(EnableInvokeDynamic, "");
1039 // If it's anonymous, initialize it now, since nobody else will.
1041 {
1042 MutexLocker mu_r(Compile_lock, THREAD);
1044 // Add to class hierarchy, initialize vtables, and do possible
1045 // deoptimizations.
1046 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1048 // But, do not add to system dictionary.
1050 // compiled code dependencies need to be validated anyway
1051 notice_modification();
1052 }
1054 // Rewrite and patch constant pool here.
1055 k->link_class(CHECK_NULL);
1056 if (cp_patches != NULL) {
1057 k->constants()->patch_resolved_references(cp_patches);
1058 }
1059 k->eager_initialize(CHECK_NULL);
1061 // notify jvmti
1062 if (JvmtiExport::should_post_class_load()) {
1063 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1064 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1065 }
1067 post_class_load_event(class_load_start_event, k, class_loader);
1068 }
1069 assert(host_klass.not_null() || cp_patches == NULL,
1070 "cp_patches only found with host_klass");
1072 return k();
1073 }
1075 // Add a klass to the system from a stream (called by jni_DefineClass and
1076 // JVM_DefineClass).
1077 // Note: class_name can be NULL. In that case we do not know the name of
1078 // the class until we have parsed the stream.
1080 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1081 Handle class_loader,
1082 Handle protection_domain,
1083 ClassFileStream* st,
1084 bool verify,
1085 TRAPS) {
1087 // Classloaders that support parallelism, e.g. bootstrap classloader,
1088 // or all classloaders with UnsyncloadClass do not acquire lock here
1089 bool DoObjectLock = true;
1090 if (is_parallelCapable(class_loader)) {
1091 DoObjectLock = false;
1092 }
1094 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1096 // Make sure we are synchronized on the class loader before we proceed
1097 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1098 check_loader_lock_contention(lockObject, THREAD);
1099 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1101 TempNewSymbol parsed_name = NULL;
1103 // Parse the stream. Note that we do this even though this klass might
1104 // already be present in the SystemDictionary, otherwise we would not
1105 // throw potential ClassFormatErrors.
1106 //
1107 // Note: "name" is updated.
1109 ClassFileParser parser(st);
1110 instanceKlassHandle k = parser.parseClassFile(class_name,
1111 loader_data,
1112 protection_domain,
1113 parsed_name,
1114 verify,
1115 THREAD);
1117 const char* pkg = "java/";
1118 size_t pkglen = strlen(pkg);
1119 if (!HAS_PENDING_EXCEPTION &&
1120 !class_loader.is_null() &&
1121 parsed_name != NULL &&
1122 parsed_name->utf8_length() >= (int)pkglen &&
1123 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1124 // It is illegal to define classes in the "java." package from
1125 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1126 ResourceMark rm(THREAD);
1127 char* name = parsed_name->as_C_string();
1128 char* index = strrchr(name, '/');
1129 assert(index != NULL, "must be");
1130 *index = '\0'; // chop to just the package name
1131 while ((index = strchr(name, '/')) != NULL) {
1132 *index = '.'; // replace '/' with '.' in package name
1133 }
1134 const char* fmt = "Prohibited package name: %s";
1135 size_t len = strlen(fmt) + strlen(name);
1136 char* message = NEW_RESOURCE_ARRAY(char, len);
1137 jio_snprintf(message, len, fmt, name);
1138 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1139 vmSymbols::java_lang_SecurityException(), message);
1140 }
1142 if (!HAS_PENDING_EXCEPTION) {
1143 assert(parsed_name != NULL, "Sanity");
1144 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1145 // Verification prevents us from creating names with dots in them, this
1146 // asserts that that's the case.
1147 assert(is_internal_format(parsed_name),
1148 "external class name format used internally");
1150 #if INCLUDE_JFR
1151 {
1152 InstanceKlass* ik = k();
1153 ON_KLASS_CREATION(ik, parser, THREAD);
1154 k = instanceKlassHandle(ik);
1155 }
1156 #endif
1158 // Add class just loaded
1159 // If a class loader supports parallel classloading handle parallel define requests
1160 // find_or_define_instance_class may return a different InstanceKlass
1161 if (is_parallelCapable(class_loader)) {
1162 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1163 } else {
1164 define_instance_class(k, THREAD);
1165 }
1166 }
1168 // Make sure we have an entry in the SystemDictionary on success
1169 debug_only( {
1170 if (!HAS_PENDING_EXCEPTION) {
1171 assert(parsed_name != NULL, "parsed_name is still null?");
1172 Symbol* h_name = k->name();
1173 ClassLoaderData *defining_loader_data = k->class_loader_data();
1175 MutexLocker mu(SystemDictionary_lock, THREAD);
1177 Klass* check = find_class(parsed_name, loader_data);
1178 assert(check == k(), "should be present in the dictionary");
1180 Klass* check2 = find_class(h_name, defining_loader_data);
1181 assert(check == check2, "name inconsistancy in SystemDictionary");
1182 }
1183 } );
1185 return k();
1186 }
1188 #if INCLUDE_CDS
1189 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1190 int number_of_entries) {
1191 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1192 "bad shared dictionary size.");
1193 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1194 }
1197 // If there is a shared dictionary, then find the entry for the
1198 // given shared system class, if any.
1200 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1201 if (shared_dictionary() != NULL) {
1202 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1203 int d_index = shared_dictionary()->hash_to_index(d_hash);
1205 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1206 } else {
1207 return NULL;
1208 }
1209 }
1212 // Load a class from the shared spaces (found through the shared system
1213 // dictionary). Force the superclass and all interfaces to be loaded.
1214 // Update the class definition to include sibling classes and no
1215 // subclasses (yet). [Classes in the shared space are not part of the
1216 // object hierarchy until loaded.]
1218 instanceKlassHandle SystemDictionary::load_shared_class(
1219 Symbol* class_name, Handle class_loader, TRAPS) {
1220 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1221 // Make sure we only return the boot class for the NULL classloader.
1222 if (ik.not_null() &&
1223 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1224 Handle protection_domain;
1225 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1226 }
1227 return instanceKlassHandle();
1228 }
1230 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1231 Handle class_loader,
1232 Handle protection_domain, TRAPS) {
1233 if (ik.not_null()) {
1234 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1235 Symbol* class_name = ik->name();
1237 // Found the class, now load the superclass and interfaces. If they
1238 // are shared, add them to the main system dictionary and reset
1239 // their hierarchy references (supers, subs, and interfaces).
1241 if (ik->super() != NULL) {
1242 Symbol* cn = ik->super()->name();
1243 Klass *s = resolve_super_or_fail(class_name, cn,
1244 class_loader, protection_domain, true, CHECK_(nh));
1245 if (s != ik->super()) {
1246 // The dynamically resolved super class is not the same as the one we used during dump time,
1247 // so we cannot use ik.
1248 return nh;
1249 }
1250 }
1252 Array<Klass*>* interfaces = ik->local_interfaces();
1253 int num_interfaces = interfaces->length();
1254 for (int index = 0; index < num_interfaces; index++) {
1255 Klass* k = interfaces->at(index);
1257 // Note: can not use InstanceKlass::cast here because
1258 // interfaces' InstanceKlass's C++ vtbls haven't been
1259 // reinitialized yet (they will be once the interface classes
1260 // are loaded)
1261 Symbol* name = k->name();
1262 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1263 if (k != i) {
1264 // The dynamically resolved interface class is not the same as the one we used during dump time,
1265 // so we cannot use ik.
1266 return nh;
1267 }
1268 }
1270 // Adjust methods to recover missing data. They need addresses for
1271 // interpreter entry points and their default native method address
1272 // must be reset.
1274 // Updating methods must be done under a lock so multiple
1275 // threads don't update these in parallel
1276 //
1277 // Shared classes are all currently loaded by either the bootstrap or
1278 // internal parallel class loaders, so this will never cause a deadlock
1279 // on a custom class loader lock.
1281 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1282 {
1283 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1284 check_loader_lock_contention(lockObject, THREAD);
1285 ObjectLocker ol(lockObject, THREAD, true);
1286 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1287 }
1289 if (TraceClassLoading) {
1290 ResourceMark rm;
1291 tty->print("[Loaded %s", ik->external_name());
1292 tty->print(" from shared objects file");
1293 if (class_loader.not_null()) {
1294 tty->print(" by %s", loader_data->loader_name());
1295 }
1296 tty->print_cr("]");
1297 }
1299 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1300 // Only dump the classes that can be stored into CDS archive
1301 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1302 ResourceMark rm(THREAD);
1303 classlist_file->print_cr("%s", ik->name()->as_C_string());
1304 classlist_file->flush();
1305 }
1306 }
1308 // notify a class loaded from shared object
1309 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1310 true /* shared class */);
1311 }
1312 return ik;
1313 }
1314 #endif // INCLUDE_CDS
1316 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1317 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1318 if (class_loader.is_null()) {
1320 // Search the shared system dictionary for classes preloaded into the
1321 // shared spaces.
1322 instanceKlassHandle k;
1323 {
1324 #if INCLUDE_CDS
1325 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1326 k = load_shared_class(class_name, class_loader, THREAD);
1327 #endif
1328 }
1330 if (k.is_null()) {
1331 // Use VM class loader
1332 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1333 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1334 }
1336 // find_or_define_instance_class may return a different InstanceKlass
1337 if (!k.is_null()) {
1338 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1339 }
1341 #if INCLUDE_JFR
1342 if (k.is_null() && (class_name == jfr_event_handler_proxy)) {
1343 assert(jfr_event_handler_proxy != NULL, "invariant");
1344 // EventHandlerProxy class is generated dynamically in
1345 // EventHandlerProxyCreator::makeEventHandlerProxyClass
1346 // method, so we generate a Java call from here.
1347 //
1348 // EventHandlerProxy class will finally be defined in
1349 // SystemDictionary::resolve_from_stream method, down
1350 // the call stack. Bootstrap classloader is parallel-capable,
1351 // so no concurrency issues are expected.
1352 CLEAR_PENDING_EXCEPTION;
1353 k = JfrUpcalls::load_event_handler_proxy_class(THREAD);
1354 assert(!k.is_null(), "invariant");
1355 }
1356 #endif
1358 return k;
1359 } else {
1360 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1361 ResourceMark rm(THREAD);
1363 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1364 JavaThread* jt = (JavaThread*) THREAD;
1366 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1367 ClassLoader::perf_app_classload_selftime(),
1368 ClassLoader::perf_app_classload_count(),
1369 jt->get_thread_stat()->perf_recursion_counts_addr(),
1370 jt->get_thread_stat()->perf_timers_addr(),
1371 PerfClassTraceTime::CLASS_LOAD);
1373 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1374 // Translate to external class name format, i.e., convert '/' chars to '.'
1375 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1377 JavaValue result(T_OBJECT);
1379 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1381 // Call public unsynchronized loadClass(String) directly for all class loaders
1382 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1383 // acquire a class-name based lock rather than the class loader object lock.
1384 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1385 // so the call to loadClassInternal() was not required.
1386 //
1387 // UnsyncloadClass flag means both call loadClass(String) and do
1388 // not acquire the class loader lock even for class loaders that are
1389 // not parallelCapable. This was a risky transitional
1390 // flag for diagnostic purposes only. It is risky to call
1391 // custom class loaders without synchronization.
1392 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1393 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1394 // Do NOT assume this will be supported in future releases.
1395 //
1396 // Added MustCallLoadClassInternal in case we discover in the field
1397 // a customer that counts on this call
1398 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1399 JavaCalls::call_special(&result,
1400 class_loader,
1401 spec_klass,
1402 vmSymbols::loadClassInternal_name(),
1403 vmSymbols::string_class_signature(),
1404 string,
1405 CHECK_(nh));
1406 } else {
1407 JavaCalls::call_virtual(&result,
1408 class_loader,
1409 spec_klass,
1410 vmSymbols::loadClass_name(),
1411 vmSymbols::string_class_signature(),
1412 string,
1413 CHECK_(nh));
1414 }
1416 assert(result.get_type() == T_OBJECT, "just checking");
1417 oop obj = (oop) result.get_jobject();
1419 // Primitive classes return null since forName() can not be
1420 // used to obtain any of the Class objects representing primitives or void
1421 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1422 instanceKlassHandle k =
1423 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1424 // For user defined Java class loaders, check that the name returned is
1425 // the same as that requested. This check is done for the bootstrap
1426 // loader when parsing the class file.
1427 if (class_name == k->name()) {
1428 return k;
1429 }
1430 }
1431 // Class is not found or has the wrong name, return NULL
1432 return nh;
1433 }
1434 }
1436 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1437 EventClassDefine event;
1438 if (event.should_commit()) {
1439 event.set_definedClass(k);
1440 event.set_definingClassLoader(def_cld);
1441 event.commit();
1442 }
1443 }
1445 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1447 ClassLoaderData* loader_data = k->class_loader_data();
1448 Handle class_loader_h(THREAD, loader_data->class_loader());
1450 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1452 // for bootstrap and other parallel classloaders don't acquire lock,
1453 // use placeholder token
1454 // If a parallelCapable class loader calls define_instance_class instead of
1455 // find_or_define_instance_class to get here, we have a timing
1456 // hole with systemDictionary updates and check_constraints
1457 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1458 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1459 compute_loader_lock_object(class_loader_h, THREAD)),
1460 "define called without lock");
1461 }
1463 // Check class-loading constraints. Throw exception if violation is detected.
1464 // Grabs and releases SystemDictionary_lock
1465 // The check_constraints/find_class call and update_dictionary sequence
1466 // must be "atomic" for a specific class/classloader pair so we never
1467 // define two different instanceKlasses for that class/classloader pair.
1468 // Existing classloaders will call define_instance_class with the
1469 // classloader lock held
1470 // Parallel classloaders will call find_or_define_instance_class
1471 // which will require a token to perform the define class
1472 Symbol* name_h = k->name();
1473 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1474 int d_index = dictionary()->hash_to_index(d_hash);
1475 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1477 // Register class just loaded with class loader (placed in Vector)
1478 // Note we do this before updating the dictionary, as this can
1479 // fail with an OutOfMemoryError (if it does, we will *not* put this
1480 // class in the dictionary and will not update the class hierarchy).
1481 // JVMTI FollowReferences needs to find the classes this way.
1482 if (k->class_loader() != NULL) {
1483 methodHandle m(THREAD, Universe::loader_addClass_method());
1484 JavaValue result(T_VOID);
1485 JavaCallArguments args(class_loader_h);
1486 args.push_oop(Handle(THREAD, k->java_mirror()));
1487 JavaCalls::call(&result, m, &args, CHECK);
1488 }
1490 // Add the new class. We need recompile lock during update of CHA.
1491 {
1492 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1493 int p_index = placeholders()->hash_to_index(p_hash);
1495 MutexLocker mu_r(Compile_lock, THREAD);
1497 // Add to class hierarchy, initialize vtables, and do possible
1498 // deoptimizations.
1499 add_to_hierarchy(k, CHECK); // No exception, but can block
1501 // Add to systemDictionary - so other classes can see it.
1502 // Grabs and releases SystemDictionary_lock
1503 update_dictionary(d_index, d_hash, p_index, p_hash,
1504 k, class_loader_h, THREAD);
1505 }
1506 k->eager_initialize(THREAD);
1508 // notify jvmti
1509 if (JvmtiExport::should_post_class_load()) {
1510 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1511 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1513 }
1515 post_class_define_event(k(), loader_data);
1516 }
1518 // Support parallel classloading
1519 // All parallel class loaders, including bootstrap classloader
1520 // lock a placeholder entry for this class/class_loader pair
1521 // to allow parallel defines of different classes for this class loader
1522 // With AllowParallelDefine flag==true, in case they do not synchronize around
1523 // FindLoadedClass/DefineClass, calls, we check for parallel
1524 // loading for them, wait if a defineClass is in progress
1525 // and return the initial requestor's results
1526 // This flag does not apply to the bootstrap classloader.
1527 // With AllowParallelDefine flag==false, call through to define_instance_class
1528 // which will throw LinkageError: duplicate class definition.
1529 // False is the requested default.
1530 // For better performance, the class loaders should synchronize
1531 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1532 // potentially waste time reading and parsing the bytestream.
1533 // Note: VM callers should ensure consistency of k/class_name,class_loader
1534 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1536 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1537 Symbol* name_h = k->name(); // passed in class_name may be null
1538 ClassLoaderData* loader_data = class_loader_data(class_loader);
1540 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1541 int d_index = dictionary()->hash_to_index(d_hash);
1543 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1544 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1545 int p_index = placeholders()->hash_to_index(p_hash);
1546 PlaceholderEntry* probe;
1548 {
1549 MutexLocker mu(SystemDictionary_lock, THREAD);
1550 // First check if class already defined
1551 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1552 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1553 if (check != NULL) {
1554 return(instanceKlassHandle(THREAD, check));
1555 }
1556 }
1558 // Acquire define token for this class/classloader
1559 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1560 // Wait if another thread defining in parallel
1561 // All threads wait - even those that will throw duplicate class: otherwise
1562 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1563 // if other thread has not finished updating dictionary
1564 while (probe->definer() != NULL) {
1565 SystemDictionary_lock->wait();
1566 }
1567 // Only special cases allow parallel defines and can use other thread's results
1568 // Other cases fall through, and may run into duplicate defines
1569 // caught by finding an entry in the SystemDictionary
1570 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1571 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1572 SystemDictionary_lock->notify_all();
1573 #ifdef ASSERT
1574 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1575 assert(check != NULL, "definer missed recording success");
1576 #endif
1577 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1578 } else {
1579 // This thread will define the class (even if earlier thread tried and had an error)
1580 probe->set_definer(THREAD);
1581 }
1582 }
1584 define_instance_class(k, THREAD);
1586 Handle linkage_exception = Handle(); // null handle
1588 // definer must notify any waiting threads
1589 {
1590 MutexLocker mu(SystemDictionary_lock, THREAD);
1591 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1592 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1593 if (probe != NULL) {
1594 if (HAS_PENDING_EXCEPTION) {
1595 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1596 CLEAR_PENDING_EXCEPTION;
1597 } else {
1598 probe->set_instance_klass(k());
1599 }
1600 probe->set_definer(NULL);
1601 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1602 SystemDictionary_lock->notify_all();
1603 }
1604 }
1606 // Can't throw exception while holding lock due to rank ordering
1607 if (linkage_exception() != NULL) {
1608 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1609 }
1611 return k;
1612 }
1613 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1614 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1615 if (class_loader.is_null()) {
1616 return Handle(THREAD, _system_loader_lock_obj);
1617 } else {
1618 return class_loader;
1619 }
1620 }
1622 // This method is added to check how often we have to wait to grab loader
1623 // lock. The results are being recorded in the performance counters defined in
1624 // ClassLoader::_sync_systemLoaderLockContentionRate and
1625 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1626 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1627 if (!UsePerfData) {
1628 return;
1629 }
1631 assert(!loader_lock.is_null(), "NULL lock object");
1633 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1634 == ObjectSynchronizer::owner_other) {
1635 // contention will likely happen, so increment the corresponding
1636 // contention counter.
1637 if (loader_lock() == _system_loader_lock_obj) {
1638 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1639 } else {
1640 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1641 }
1642 }
1643 }
1645 // ----------------------------------------------------------------------------
1646 // Lookup
1648 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1649 Symbol* class_name,
1650 ClassLoaderData* loader_data) {
1651 assert_locked_or_safepoint(SystemDictionary_lock);
1652 assert (index == dictionary()->index_for(class_name, loader_data),
1653 "incorrect index?");
1655 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1656 return k;
1657 }
1660 // Basic find on classes in the midst of being loaded
1661 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1662 ClassLoaderData* loader_data) {
1663 assert_locked_or_safepoint(SystemDictionary_lock);
1664 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1665 int p_index = placeholders()->hash_to_index(p_hash);
1666 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1667 }
1670 // Used for assertions and verification only
1671 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1672 #ifndef ASSERT
1673 guarantee(VerifyBeforeGC ||
1674 VerifyDuringGC ||
1675 VerifyBeforeExit ||
1676 VerifyDuringStartup ||
1677 VerifyAfterGC, "too expensive");
1678 #endif
1679 assert_locked_or_safepoint(SystemDictionary_lock);
1681 // First look in the loaded class array
1682 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1683 int d_index = dictionary()->hash_to_index(d_hash);
1684 return find_class(d_index, d_hash, class_name, loader_data);
1685 }
1688 // Get the next class in the diictionary.
1689 Klass* SystemDictionary::try_get_next_class() {
1690 return dictionary()->try_get_next_class();
1691 }
1694 // ----------------------------------------------------------------------------
1695 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1696 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1697 // before a new class is used.
1699 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1700 assert(k.not_null(), "just checking");
1701 assert_locked_or_safepoint(Compile_lock);
1703 // Link into hierachy. Make sure the vtables are initialized before linking into
1704 k->append_to_sibling_list(); // add to superklass/sibling list
1705 k->process_interfaces(THREAD); // handle all "implements" declarations
1706 k->set_init_state(InstanceKlass::loaded);
1707 // Now flush all code that depended on old class hierarchy.
1708 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1709 // Also, first reinitialize vtable because it may have gotten out of synch
1710 // while the new class wasn't connected to the class hierarchy.
1711 Universe::flush_dependents_on(k);
1712 }
1714 // ----------------------------------------------------------------------------
1715 // GC support
1717 // Following roots during mark-sweep is separated in two phases.
1718 //
1719 // The first phase follows preloaded classes and all other system
1720 // classes, since these will never get unloaded anyway.
1721 //
1722 // The second phase removes (unloads) unreachable classes from the
1723 // system dictionary and follows the remaining classes' contents.
1725 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1726 roots_oops_do(blk, NULL);
1727 }
1729 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1730 // Follow all system classes and temporary placeholders in dictionary
1731 dictionary()->always_strong_classes_do(closure);
1733 // Placeholders. These represent classes we're actively loading.
1734 placeholders()->classes_do(closure);
1735 }
1737 // Calculate a "good" systemdictionary size based
1738 // on predicted or current loaded classes count
1739 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1740 int newsize = _old_default_sdsize;
1741 if ((classcount > 0) && !DumpSharedSpaces) {
1742 int desiredsize = classcount/_average_depth_goal;
1743 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1744 newsize = _primelist[++_sdgeneration]) {
1745 if (desiredsize <= newsize) {
1746 break;
1747 }
1748 }
1749 }
1750 return newsize;
1751 }
1753 #ifdef ASSERT
1754 class VerifySDReachableAndLiveClosure : public OopClosure {
1755 private:
1756 BoolObjectClosure* _is_alive;
1758 template <class T> void do_oop_work(T* p) {
1759 oop obj = oopDesc::load_decode_heap_oop(p);
1760 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1761 }
1763 public:
1764 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1766 virtual void do_oop(oop* p) { do_oop_work(p); }
1767 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1768 };
1769 #endif
1771 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1772 // Note: anonymous classes are not in the SD.
1773 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1774 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1775 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1776 if (unloading_occurred) {
1777 JFR_ONLY(Jfr::on_unloading_classes();)
1778 dictionary()->do_unloading();
1779 constraints()->purge_loader_constraints();
1780 resolution_errors()->purge_resolution_errors();
1781 }
1782 // Oops referenced by the system dictionary may get unreachable independently
1783 // of the class loader (eg. cached protection domain oops). So we need to
1784 // explicitly unlink them here instead of in Dictionary::do_unloading.
1785 dictionary()->unlink(is_alive);
1786 #ifdef ASSERT
1787 VerifySDReachableAndLiveClosure cl(is_alive);
1788 dictionary()->oops_do(&cl);
1789 #endif
1790 return unloading_occurred;
1791 }
1793 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1794 strong->do_oop(&_java_system_loader);
1795 strong->do_oop(&_system_loader_lock_obj);
1796 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1798 // Adjust dictionary
1799 dictionary()->roots_oops_do(strong, weak);
1801 // Visit extra methods
1802 invoke_method_table()->oops_do(strong);
1803 }
1805 void SystemDictionary::oops_do(OopClosure* f) {
1806 f->do_oop(&_java_system_loader);
1807 f->do_oop(&_system_loader_lock_obj);
1808 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1810 // Adjust dictionary
1811 dictionary()->oops_do(f);
1813 // Visit extra methods
1814 invoke_method_table()->oops_do(f);
1815 }
1817 // Extended Class redefinition support.
1818 // If one of these classes is replaced, we need to replace it in these places.
1819 // KlassClosure::do_klass should take the address of a class but we can
1820 // change that later.
1821 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1822 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1823 f->do_klass(_well_known_klasses[k]);
1824 }
1826 {
1827 for (int i = 0; i < T_VOID+1; i++) {
1828 if (_box_klasses[i] != NULL) {
1829 assert(i >= T_BOOLEAN, "checking");
1830 f->do_klass(_box_klasses[i]);
1831 }
1832 }
1833 }
1835 FilteredFieldsMap::classes_do(f);
1836 }
1838 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1839 f->do_klass(_abstract_ownable_synchronizer_klass);
1840 }
1842 // Just the classes from defining class loaders
1843 // Don't iterate over placeholders
1844 void SystemDictionary::classes_do(void f(Klass*)) {
1845 dictionary()->classes_do(f);
1846 }
1848 // Added for initialize_itable_for_klass
1849 // Just the classes from defining class loaders
1850 // Don't iterate over placeholders
1851 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1852 dictionary()->classes_do(f, CHECK);
1853 }
1855 // All classes, and their class loaders
1856 // Don't iterate over placeholders
1857 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1858 dictionary()->classes_do(f);
1859 }
1861 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1862 placeholders()->entries_do(f);
1863 }
1865 void SystemDictionary::methods_do(void f(Method*)) {
1866 dictionary()->methods_do(f);
1867 invoke_method_table()->methods_do(f);
1868 }
1870 void SystemDictionary::remove_classes_in_error_state() {
1871 dictionary()->remove_classes_in_error_state();
1872 }
1874 // ----------------------------------------------------------------------------
1875 // Lazily load klasses
1877 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1878 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1880 // if multiple threads calling this function, only one thread will load
1881 // the class. The other threads will find the loaded version once the
1882 // class is loaded.
1883 Klass* aos = _abstract_ownable_synchronizer_klass;
1884 if (aos == NULL) {
1885 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1886 // Force a fence to prevent any read before the write completes
1887 OrderAccess::fence();
1888 _abstract_ownable_synchronizer_klass = k;
1889 }
1890 }
1892 // ----------------------------------------------------------------------------
1893 // Initialization
1895 void SystemDictionary::initialize(TRAPS) {
1896 // Allocate arrays
1897 assert(dictionary() == NULL,
1898 "SystemDictionary should only be initialized once");
1899 _sdgeneration = 0;
1900 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1901 _placeholders = new PlaceholderTable(_nof_buckets);
1902 _number_of_modifications = 0;
1903 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1904 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1905 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1907 // Allocate private object used as system class loader lock
1908 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1909 // Initialize basic classes
1910 initialize_preloaded_classes(CHECK);
1911 #if INCLUDE_JFR
1912 jfr_event_handler_proxy = SymbolTable::new_permanent_symbol("jdk/jfr/proxy/internal/EventHandlerProxy", CHECK);
1913 #endif // INCLUDE_JFR
1914 }
1916 // Compact table of directions on the initialization of klasses:
1917 static const short wk_init_info[] = {
1918 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1919 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1920 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1921 | (int)SystemDictionary::option ),
1922 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1923 #undef WK_KLASS_INIT_INFO
1924 0
1925 };
1927 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1928 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1929 int info = wk_init_info[id - FIRST_WKID];
1930 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1931 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1932 Klass** klassp = &_well_known_klasses[id];
1933 bool must_load = (init_opt < SystemDictionary::Opt);
1934 if ((*klassp) == NULL) {
1935 if (must_load) {
1936 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1937 } else {
1938 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1939 }
1940 }
1941 return ((*klassp) != NULL);
1942 }
1944 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1945 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1946 for (int id = (int)start_id; id < (int)limit_id; id++) {
1947 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1948 int info = wk_init_info[id - FIRST_WKID];
1949 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1950 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1952 initialize_wk_klass((WKID)id, opt, CHECK);
1953 }
1955 // move the starting value forward to the limit:
1956 start_id = limit_id;
1957 }
1959 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1960 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1961 // Preload commonly used klasses
1962 WKID scan = FIRST_WKID;
1963 // first do Object, then String, Class
1964 if (UseSharedSpaces) {
1965 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1966 // Initialize the constant pool for the Object_class
1967 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1968 ik->constants()->restore_unshareable_info(CHECK);
1969 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1970 } else {
1971 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1972 }
1974 // Calculate offsets for String and Class classes since they are loaded and
1975 // can be used after this point.
1976 java_lang_String::compute_offsets();
1977 java_lang_Class::compute_offsets();
1979 // Fixup mirrors for classes loaded before java.lang.Class.
1980 // These calls iterate over the objects currently in the perm gen
1981 // so calling them at this point is matters (not before when there
1982 // are fewer objects and not later after there are more objects
1983 // in the perm gen.
1984 Universe::initialize_basic_type_mirrors(CHECK);
1985 Universe::fixup_mirrors(CHECK);
1987 // do a bunch more:
1988 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
1990 // Preload ref klasses and set reference types
1991 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
1992 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
1994 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
1995 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
1996 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
1997 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
1998 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
1999 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
2001 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
2003 // JSR 292 classes
2004 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2005 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2006 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2007 if (EnableInvokeDynamic) {
2008 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2009 } else {
2010 // Skip the JSR 292 classes, if not enabled.
2011 scan = WKID(jsr292_group_end + 1);
2012 }
2014 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2016 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2017 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2018 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2019 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2020 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2021 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2022 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2023 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2024 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2025 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2027 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2028 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2029 _has_loadClassInternal = (method != NULL);
2030 }
2031 { // Compute whether we should use checkPackageAccess or NOT
2032 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2033 _has_checkPackageAccess = (method != NULL);
2034 }
2035 }
2037 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2038 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2039 BasicType SystemDictionary::box_klass_type(Klass* k) {
2040 assert(k != NULL, "");
2041 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2042 if (_box_klasses[i] == k)
2043 return (BasicType)i;
2044 }
2045 return T_OBJECT;
2046 }
2048 // Constraints on class loaders. The details of the algorithm can be
2049 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2050 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2051 // that the system dictionary needs to maintain a set of contraints that
2052 // must be satisfied by all classes in the dictionary.
2053 // if defining is true, then LinkageError if already in systemDictionary
2054 // if initiating loader, then ok if InstanceKlass matches existing entry
2056 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2057 instanceKlassHandle k,
2058 Handle class_loader, bool defining,
2059 TRAPS) {
2060 const char *linkage_error = NULL;
2061 {
2062 Symbol* name = k->name();
2063 ClassLoaderData *loader_data = class_loader_data(class_loader);
2065 MutexLocker mu(SystemDictionary_lock, THREAD);
2067 Klass* check = find_class(d_index, d_hash, name, loader_data);
2068 if (check != (Klass*)NULL) {
2069 // if different InstanceKlass - duplicate class definition,
2070 // else - ok, class loaded by a different thread in parallel,
2071 // we should only have found it if it was done loading and ok to use
2072 // system dictionary only holds instance classes, placeholders
2073 // also holds array classes
2075 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2076 if ((defining == true) || (k() != check)) {
2077 linkage_error = "loader (instance of %s): attempted duplicate class "
2078 "definition for name: \"%s\"";
2079 } else {
2080 return;
2081 }
2082 }
2084 #ifdef ASSERT
2085 Symbol* ph_check = find_placeholder(name, loader_data);
2086 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2087 #endif
2089 if (linkage_error == NULL) {
2090 if (constraints()->check_or_update(k, class_loader, name) == false) {
2091 linkage_error = "loader constraint violation: loader (instance of %s)"
2092 " previously initiated loading for a different type with name \"%s\"";
2093 }
2094 }
2095 }
2097 // Throw error now if needed (cannot throw while holding
2098 // SystemDictionary_lock because of rank ordering)
2100 if (linkage_error) {
2101 ResourceMark rm(THREAD);
2102 const char* class_loader_name = loader_name(class_loader());
2103 char* type_name = k->name()->as_C_string();
2104 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2105 strlen(type_name);
2106 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2107 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2108 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2109 }
2110 }
2113 // Update system dictionary - done after check_constraint and add_to_hierachy
2114 // have been called.
2115 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2116 int p_index, unsigned int p_hash,
2117 instanceKlassHandle k,
2118 Handle class_loader,
2119 TRAPS) {
2120 // Compile_lock prevents systemDictionary updates during compilations
2121 assert_locked_or_safepoint(Compile_lock);
2122 Symbol* name = k->name();
2123 ClassLoaderData *loader_data = class_loader_data(class_loader);
2125 {
2126 MutexLocker mu1(SystemDictionary_lock, THREAD);
2128 // See whether biased locking is enabled and if so set it for this
2129 // klass.
2130 // Note that this must be done past the last potential blocking
2131 // point / safepoint. We enable biased locking lazily using a
2132 // VM_Operation to iterate the SystemDictionary and installing the
2133 // biasable mark word into each InstanceKlass's prototype header.
2134 // To avoid race conditions where we accidentally miss enabling the
2135 // optimization for one class in the process of being added to the
2136 // dictionary, we must not safepoint after the test of
2137 // BiasedLocking::enabled().
2138 if (UseBiasedLocking && BiasedLocking::enabled()) {
2139 // Set biased locking bit for all loaded classes; it will be
2140 // cleared if revocation occurs too often for this type
2141 // NOTE that we must only do this when the class is initally
2142 // defined, not each time it is referenced from a new class loader
2143 if (k->class_loader() == class_loader()) {
2144 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2145 }
2146 }
2148 // Make a new system dictionary entry.
2149 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2150 if (sd_check == NULL) {
2151 dictionary()->add_klass(name, loader_data, k);
2152 notice_modification();
2153 }
2154 #ifdef ASSERT
2155 sd_check = find_class(d_index, d_hash, name, loader_data);
2156 assert (sd_check != NULL, "should have entry in system dictionary");
2157 // Note: there may be a placeholder entry: for circularity testing
2158 // or for parallel defines
2159 #endif
2160 SystemDictionary_lock->notify_all();
2161 }
2162 }
2165 // Try to find a class name using the loader constraints. The
2166 // loader constraints might know about a class that isn't fully loaded
2167 // yet and these will be ignored.
2168 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2169 Symbol* class_name, Handle class_loader, TRAPS) {
2171 // First see if it has been loaded directly.
2172 // Force the protection domain to be null. (This removes protection checks.)
2173 Handle no_protection_domain;
2174 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2175 no_protection_domain, CHECK_NULL);
2176 if (klass != NULL)
2177 return klass;
2179 // Now look to see if it has been loaded elsewhere, and is subject to
2180 // a loader constraint that would require this loader to return the
2181 // klass that is already loaded.
2182 if (FieldType::is_array(class_name)) {
2183 // For array classes, their Klass*s are not kept in the
2184 // constraint table. The element Klass*s are.
2185 FieldArrayInfo fd;
2186 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2187 if (t != T_OBJECT) {
2188 klass = Universe::typeArrayKlassObj(t);
2189 } else {
2190 MutexLocker mu(SystemDictionary_lock, THREAD);
2191 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2192 }
2193 // If element class already loaded, allocate array klass
2194 if (klass != NULL) {
2195 klass = klass->array_klass_or_null(fd.dimension());
2196 }
2197 } else {
2198 MutexLocker mu(SystemDictionary_lock, THREAD);
2199 // Non-array classes are easy: simply check the constraint table.
2200 klass = constraints()->find_constrained_klass(class_name, class_loader);
2201 }
2203 return klass;
2204 }
2207 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2208 Handle class_loader1,
2209 Handle class_loader2,
2210 Thread* THREAD) {
2211 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2212 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2214 Symbol* constraint_name = NULL;
2215 if (!FieldType::is_array(class_name)) {
2216 constraint_name = class_name;
2217 } else {
2218 // For array classes, their Klass*s are not kept in the
2219 // constraint table. The element classes are.
2220 FieldArrayInfo fd;
2221 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2222 // primitive types always pass
2223 if (t != T_OBJECT) {
2224 return true;
2225 } else {
2226 constraint_name = fd.object_key();
2227 }
2228 }
2229 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2230 int d_index1 = dictionary()->hash_to_index(d_hash1);
2232 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2233 int d_index2 = dictionary()->hash_to_index(d_hash2);
2234 {
2235 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2237 // Better never do a GC while we're holding these oops
2238 No_Safepoint_Verifier nosafepoint;
2240 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2241 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2242 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2243 klass2, class_loader2);
2244 }
2245 }
2247 // Add entry to resolution error table to record the error when the first
2248 // attempt to resolve a reference to a class has failed.
2249 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
2250 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2251 int index = resolution_errors()->hash_to_index(hash);
2252 {
2253 MutexLocker ml(SystemDictionary_lock, Thread::current());
2254 resolution_errors()->add_entry(index, hash, pool, which, error);
2255 }
2256 }
2258 // Delete a resolution error for RedefineClasses for a constant pool is going away
2259 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2260 resolution_errors()->delete_entry(pool);
2261 }
2263 // Lookup resolution error table. Returns error if found, otherwise NULL.
2264 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2265 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2266 int index = resolution_errors()->hash_to_index(hash);
2267 {
2268 MutexLocker ml(SystemDictionary_lock, Thread::current());
2269 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2270 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2271 }
2272 }
2275 // Signature constraints ensure that callers and callees agree about
2276 // the meaning of type names in their signatures. This routine is the
2277 // intake for constraints. It collects them from several places:
2278 //
2279 // * LinkResolver::resolve_method (if check_access is true) requires
2280 // that the resolving class (the caller) and the defining class of
2281 // the resolved method (the callee) agree on each type in the
2282 // method's signature.
2283 //
2284 // * LinkResolver::resolve_interface_method performs exactly the same
2285 // checks.
2286 //
2287 // * LinkResolver::resolve_field requires that the constant pool
2288 // attempting to link to a field agree with the field's defining
2289 // class about the type of the field signature.
2290 //
2291 // * klassVtable::initialize_vtable requires that, when a class
2292 // overrides a vtable entry allocated by a superclass, that the
2293 // overriding method (i.e., the callee) agree with the superclass
2294 // on each type in the method's signature.
2295 //
2296 // * klassItable::initialize_itable requires that, when a class fills
2297 // in its itables, for each non-abstract method installed in an
2298 // itable, the method (i.e., the callee) agree with the interface
2299 // on each type in the method's signature.
2300 //
2301 // All those methods have a boolean (check_access, checkconstraints)
2302 // which turns off the checks. This is used from specialized contexts
2303 // such as bootstrapping, dumping, and debugging.
2304 //
2305 // No direct constraint is placed between the class and its
2306 // supertypes. Constraints are only placed along linked relations
2307 // between callers and callees. When a method overrides or implements
2308 // an abstract method in a supertype (superclass or interface), the
2309 // constraints are placed as if the supertype were the caller to the
2310 // overriding method. (This works well, since callers to the
2311 // supertype have already established agreement between themselves and
2312 // the supertype.) As a result of all this, a class can disagree with
2313 // its supertype about the meaning of a type name, as long as that
2314 // class neither calls a relevant method of the supertype, nor is
2315 // called (perhaps via an override) from the supertype.
2316 //
2317 //
2318 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2319 //
2320 // Make sure all class components (including arrays) in the given
2321 // signature will be resolved to the same class in both loaders.
2322 // Returns the name of the type that failed a loader constraint check, or
2323 // NULL if no constraint failed. No exception except OOME is thrown.
2324 // Arrays are not added to the loader constraint table, their elements are.
2325 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2326 Handle loader1, Handle loader2,
2327 bool is_method, TRAPS) {
2328 // Nothing to do if loaders are the same.
2329 if (loader1() == loader2()) {
2330 return NULL;
2331 }
2333 SignatureStream sig_strm(signature, is_method);
2334 while (!sig_strm.is_done()) {
2335 if (sig_strm.is_object()) {
2336 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2337 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2338 return sig;
2339 }
2340 }
2341 sig_strm.next();
2342 }
2343 return NULL;
2344 }
2347 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2348 Symbol* signature,
2349 TRAPS) {
2350 methodHandle empty;
2351 assert(EnableInvokeDynamic, "");
2352 assert(MethodHandles::is_signature_polymorphic(iid) &&
2353 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2354 iid != vmIntrinsics::_invokeGeneric,
2355 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2357 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2358 int index = invoke_method_table()->hash_to_index(hash);
2359 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2360 methodHandle m;
2361 if (spe == NULL || spe->method() == NULL) {
2362 spe = NULL;
2363 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2364 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2365 if (!Arguments::is_interpreter_only()) {
2366 // Generate a compiled form of the MH intrinsic.
2367 AdapterHandlerLibrary::create_native_wrapper(m);
2368 // Check if have the compiled code.
2369 if (!m->has_compiled_code()) {
2370 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2371 "out of space in CodeCache for method handle intrinsic", empty);
2372 }
2373 }
2374 // Now grab the lock. We might have to throw away the new method,
2375 // if a racing thread has managed to install one at the same time.
2376 {
2377 MutexLocker ml(SystemDictionary_lock, THREAD);
2378 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2379 if (spe == NULL)
2380 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2381 if (spe->method() == NULL)
2382 spe->set_method(m());
2383 }
2384 }
2386 assert(spe != NULL && spe->method() != NULL, "");
2387 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2388 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2389 "MH intrinsic invariant");
2390 return spe->method();
2391 }
2393 // Helper for unpacking the return value from linkMethod and linkCallSite.
2394 static methodHandle unpack_method_and_appendix(Handle mname,
2395 KlassHandle accessing_klass,
2396 objArrayHandle appendix_box,
2397 Handle* appendix_result,
2398 TRAPS) {
2399 methodHandle empty;
2400 if (mname.not_null()) {
2401 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2402 if (vmtarget != NULL && vmtarget->is_method()) {
2403 Method* m = (Method*)vmtarget;
2404 oop appendix = appendix_box->obj_at(0);
2405 if (TraceMethodHandles) {
2406 #ifndef PRODUCT
2407 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2408 m->print();
2409 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2410 tty->cr();
2411 #endif //PRODUCT
2412 }
2413 (*appendix_result) = Handle(THREAD, appendix);
2414 // the target is stored in the cpCache and if a reference to this
2415 // MethodName is dropped we need a way to make sure the
2416 // class_loader containing this method is kept alive.
2417 // FIXME: the appendix might also preserve this dependency.
2418 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2419 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2420 return methodHandle(THREAD, m);
2421 }
2422 }
2423 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2424 return empty;
2425 }
2427 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2428 Symbol* signature,
2429 KlassHandle accessing_klass,
2430 Handle *appendix_result,
2431 Handle *method_type_result,
2432 TRAPS) {
2433 methodHandle empty;
2434 assert(EnableInvokeDynamic, "");
2435 assert(!THREAD->is_Compiler_thread(), "");
2436 Handle method_type =
2437 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2439 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2440 int ref_kind = JVM_REF_invokeVirtual;
2441 Handle name_str = StringTable::intern(name, CHECK_(empty));
2442 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2443 assert(appendix_box->obj_at(0) == NULL, "");
2445 // This should not happen. JDK code should take care of that.
2446 if (accessing_klass.is_null() || method_type.is_null()) {
2447 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2448 }
2450 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2451 JavaCallArguments args;
2452 args.push_oop(accessing_klass()->java_mirror());
2453 args.push_int(ref_kind);
2454 args.push_oop(mh_klass()->java_mirror());
2455 args.push_oop(name_str());
2456 args.push_oop(method_type());
2457 args.push_oop(appendix_box());
2458 JavaValue result(T_OBJECT);
2459 JavaCalls::call_static(&result,
2460 SystemDictionary::MethodHandleNatives_klass(),
2461 vmSymbols::linkMethod_name(),
2462 vmSymbols::linkMethod_signature(),
2463 &args, CHECK_(empty));
2464 Handle mname(THREAD, (oop) result.get_jobject());
2465 (*method_type_result) = method_type;
2466 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2467 }
2469 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2470 // We must ensure that all class loaders everywhere will reach this class, for any client.
2471 // This is a safe bet for public classes in java.lang, such as Object and String.
2472 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2473 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2474 static bool is_always_visible_class(oop mirror) {
2475 Klass* klass = java_lang_Class::as_Klass(mirror);
2476 if (klass->oop_is_objArray()) {
2477 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2478 }
2479 if (klass->oop_is_typeArray()) {
2480 return true; // primitive array
2481 }
2482 assert(klass->oop_is_instance(), klass->external_name());
2483 return klass->is_public() &&
2484 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2485 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2486 }
2488 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2489 // signature, as interpreted relative to the given class loader.
2490 // Because of class loader constraints, all method handle usage must be
2491 // consistent with this loader.
2492 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2493 KlassHandle accessing_klass,
2494 TRAPS) {
2495 Handle empty;
2496 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2497 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2498 int index = invoke_method_table()->hash_to_index(hash);
2499 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2500 if (spe != NULL && spe->method_type() != NULL) {
2501 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2502 return Handle(THREAD, spe->method_type());
2503 } else if (THREAD->is_Compiler_thread()) {
2504 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2505 return Handle(); // do not attempt from within compiler, unless it was cached
2506 }
2508 Handle class_loader, protection_domain;
2509 if (accessing_klass.not_null()) {
2510 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2511 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2512 }
2513 bool can_be_cached = true;
2514 int npts = ArgumentCount(signature).size();
2515 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2516 int arg = 0;
2517 Handle rt; // the return type from the signature
2518 ResourceMark rm(THREAD);
2519 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2520 oop mirror = NULL;
2521 if (can_be_cached) {
2522 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2523 mirror = ss.as_java_mirror(Handle(), Handle(),
2524 SignatureStream::ReturnNull, CHECK_(empty));
2525 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2526 // Fall back to accessing_klass context.
2527 can_be_cached = false;
2528 }
2529 }
2530 if (!can_be_cached) {
2531 // Resolve, throwing a real error if it doesn't work.
2532 mirror = ss.as_java_mirror(class_loader, protection_domain,
2533 SignatureStream::NCDFError, CHECK_(empty));
2534 }
2535 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2536 if (ss.at_return_type())
2537 rt = Handle(THREAD, mirror);
2538 else
2539 pts->obj_at_put(arg++, mirror);
2541 // Check accessibility.
2542 if (ss.is_object() && accessing_klass.not_null()) {
2543 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2544 mirror = NULL; // safety
2545 // Emulate ConstantPool::verify_constant_pool_resolve.
2546 if (sel_klass->oop_is_objArray())
2547 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2548 if (sel_klass->oop_is_instance()) {
2549 KlassHandle sel_kh(THREAD, sel_klass);
2550 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2551 }
2552 }
2553 }
2554 assert(arg == npts, "");
2556 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2557 JavaCallArguments args(Handle(THREAD, rt()));
2558 args.push_oop(pts());
2559 JavaValue result(T_OBJECT);
2560 JavaCalls::call_static(&result,
2561 SystemDictionary::MethodHandleNatives_klass(),
2562 vmSymbols::findMethodHandleType_name(),
2563 vmSymbols::findMethodHandleType_signature(),
2564 &args, CHECK_(empty));
2565 Handle method_type(THREAD, (oop) result.get_jobject());
2567 if (can_be_cached) {
2568 // We can cache this MethodType inside the JVM.
2569 MutexLocker ml(SystemDictionary_lock, THREAD);
2570 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2571 if (spe == NULL)
2572 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2573 if (spe->method_type() == NULL) {
2574 spe->set_method_type(method_type());
2575 }
2576 }
2578 // report back to the caller with the MethodType
2579 return method_type;
2580 }
2582 // Ask Java code to find or construct a method handle constant.
2583 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2584 int ref_kind, //e.g., JVM_REF_invokeVirtual
2585 KlassHandle callee,
2586 Symbol* name_sym,
2587 Symbol* signature,
2588 TRAPS) {
2589 Handle empty;
2590 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2591 Handle type;
2592 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2593 type = find_method_handle_type(signature, caller, CHECK_(empty));
2594 } else if (caller.is_null()) {
2595 // This should not happen. JDK code should take care of that.
2596 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2597 } else {
2598 ResourceMark rm(THREAD);
2599 SignatureStream ss(signature, false);
2600 if (!ss.is_done()) {
2601 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2602 SignatureStream::NCDFError, CHECK_(empty));
2603 type = Handle(THREAD, mirror);
2604 ss.next();
2605 if (!ss.is_done()) type = Handle(); // error!
2606 }
2607 }
2608 if (type.is_null()) {
2609 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2610 }
2612 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2613 JavaCallArguments args;
2614 args.push_oop(caller->java_mirror()); // the referring class
2615 args.push_int(ref_kind);
2616 args.push_oop(callee->java_mirror()); // the target class
2617 args.push_oop(name());
2618 args.push_oop(type());
2619 JavaValue result(T_OBJECT);
2620 JavaCalls::call_static(&result,
2621 SystemDictionary::MethodHandleNatives_klass(),
2622 vmSymbols::linkMethodHandleConstant_name(),
2623 vmSymbols::linkMethodHandleConstant_signature(),
2624 &args, CHECK_(empty));
2625 return Handle(THREAD, (oop) result.get_jobject());
2626 }
2628 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2629 // name and signature, as interpreted relative to the given class loader.
2630 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2631 Handle bootstrap_specifier,
2632 Symbol* name,
2633 Symbol* type,
2634 Handle *appendix_result,
2635 Handle *method_type_result,
2636 TRAPS) {
2637 methodHandle empty;
2638 Handle bsm, info;
2639 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2640 bsm = bootstrap_specifier;
2641 } else {
2642 assert(bootstrap_specifier->is_objArray(), "");
2643 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2644 int len = args->length();
2645 assert(len >= 1, "");
2646 bsm = Handle(THREAD, args->obj_at(0));
2647 if (len > 1) {
2648 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2649 for (int i = 1; i < len; i++)
2650 args1->obj_at_put(i-1, args->obj_at(i));
2651 info = Handle(THREAD, args1);
2652 }
2653 }
2654 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2655 "caller must supply a valid BSM");
2657 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2658 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2660 // This should not happen. JDK code should take care of that.
2661 if (caller.is_null() || method_type.is_null()) {
2662 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2663 }
2665 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2666 assert(appendix_box->obj_at(0) == NULL, "");
2668 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2669 JavaCallArguments args;
2670 args.push_oop(caller->java_mirror());
2671 args.push_oop(bsm());
2672 args.push_oop(method_name());
2673 args.push_oop(method_type());
2674 args.push_oop(info());
2675 args.push_oop(appendix_box);
2676 JavaValue result(T_OBJECT);
2677 JavaCalls::call_static(&result,
2678 SystemDictionary::MethodHandleNatives_klass(),
2679 vmSymbols::linkCallSite_name(),
2680 vmSymbols::linkCallSite_signature(),
2681 &args, CHECK_(empty));
2682 Handle mname(THREAD, (oop) result.get_jobject());
2683 (*method_type_result) = method_type;
2684 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2685 }
2687 // Since the identity hash code for symbols changes when the symbols are
2688 // moved from the regular perm gen (hash in the mark word) to the shared
2689 // spaces (hash is the address), the classes loaded into the dictionary
2690 // may be in the wrong buckets.
2692 void SystemDictionary::reorder_dictionary() {
2693 dictionary()->reorder_dictionary();
2694 }
2697 void SystemDictionary::copy_buckets(char** top, char* end) {
2698 dictionary()->copy_buckets(top, end);
2699 }
2702 void SystemDictionary::copy_table(char** top, char* end) {
2703 dictionary()->copy_table(top, end);
2704 }
2707 void SystemDictionary::reverse() {
2708 dictionary()->reverse();
2709 }
2711 int SystemDictionary::number_of_classes() {
2712 return dictionary()->number_of_entries();
2713 }
2716 // ----------------------------------------------------------------------------
2717 void SystemDictionary::print_shared(bool details) {
2718 shared_dictionary()->print(details);
2719 }
2721 void SystemDictionary::print(bool details) {
2722 dictionary()->print(details);
2724 // Placeholders
2725 GCMutexLocker mu(SystemDictionary_lock);
2726 placeholders()->print();
2728 // loader constraints - print under SD_lock
2729 constraints()->print();
2730 }
2733 void SystemDictionary::verify() {
2734 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2735 guarantee(constraints() != NULL,
2736 "Verify of loader constraints failed");
2737 guarantee(dictionary()->number_of_entries() >= 0 &&
2738 placeholders()->number_of_entries() >= 0,
2739 "Verify of system dictionary failed");
2741 // Verify dictionary
2742 dictionary()->verify();
2744 GCMutexLocker mu(SystemDictionary_lock);
2745 placeholders()->verify();
2747 // Verify constraint table
2748 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2749 constraints()->verify(dictionary(), placeholders());
2750 }
2752 #ifndef PRODUCT
2754 // statistics code
2755 class ClassStatistics: AllStatic {
2756 private:
2757 static int nclasses; // number of classes
2758 static int nmethods; // number of methods
2759 static int nmethoddata; // number of methodData
2760 static int class_size; // size of class objects in words
2761 static int method_size; // size of method objects in words
2762 static int debug_size; // size of debug info in methods
2763 static int methoddata_size; // size of methodData objects in words
2765 static void do_class(Klass* k) {
2766 nclasses++;
2767 class_size += k->size();
2768 if (k->oop_is_instance()) {
2769 InstanceKlass* ik = (InstanceKlass*)k;
2770 class_size += ik->methods()->size();
2771 class_size += ik->constants()->size();
2772 class_size += ik->local_interfaces()->size();
2773 class_size += ik->transitive_interfaces()->size();
2774 // We do not have to count implementors, since we only store one!
2775 // SSS: How should these be accounted now that they have moved?
2776 // class_size += ik->fields()->length();
2777 }
2778 }
2780 static void do_method(Method* m) {
2781 nmethods++;
2782 method_size += m->size();
2783 // class loader uses same objArray for empty vectors, so don't count these
2784 if (m->has_stackmap_table()) {
2785 method_size += m->stackmap_data()->size();
2786 }
2788 MethodData* mdo = m->method_data();
2789 if (mdo != NULL) {
2790 nmethoddata++;
2791 methoddata_size += mdo->size();
2792 }
2793 }
2795 public:
2796 static void print() {
2797 SystemDictionary::classes_do(do_class);
2798 SystemDictionary::methods_do(do_method);
2799 tty->print_cr("Class statistics:");
2800 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2801 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2802 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2803 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2804 }
2805 };
2808 int ClassStatistics::nclasses = 0;
2809 int ClassStatistics::nmethods = 0;
2810 int ClassStatistics::nmethoddata = 0;
2811 int ClassStatistics::class_size = 0;
2812 int ClassStatistics::method_size = 0;
2813 int ClassStatistics::debug_size = 0;
2814 int ClassStatistics::methoddata_size = 0;
2816 void SystemDictionary::print_class_statistics() {
2817 ResourceMark rm;
2818 ClassStatistics::print();
2819 }
2822 class MethodStatistics: AllStatic {
2823 public:
2824 enum {
2825 max_parameter_size = 10
2826 };
2827 private:
2829 static int _number_of_methods;
2830 static int _number_of_final_methods;
2831 static int _number_of_static_methods;
2832 static int _number_of_native_methods;
2833 static int _number_of_synchronized_methods;
2834 static int _number_of_profiled_methods;
2835 static int _number_of_bytecodes;
2836 static int _parameter_size_profile[max_parameter_size];
2837 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2839 static void initialize() {
2840 _number_of_methods = 0;
2841 _number_of_final_methods = 0;
2842 _number_of_static_methods = 0;
2843 _number_of_native_methods = 0;
2844 _number_of_synchronized_methods = 0;
2845 _number_of_profiled_methods = 0;
2846 _number_of_bytecodes = 0;
2847 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2848 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2849 };
2851 static void do_method(Method* m) {
2852 _number_of_methods++;
2853 // collect flag info
2854 if (m->is_final() ) _number_of_final_methods++;
2855 if (m->is_static() ) _number_of_static_methods++;
2856 if (m->is_native() ) _number_of_native_methods++;
2857 if (m->is_synchronized()) _number_of_synchronized_methods++;
2858 if (m->method_data() != NULL) _number_of_profiled_methods++;
2859 // collect parameter size info (add one for receiver, if any)
2860 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2861 // collect bytecodes info
2862 {
2863 Thread *thread = Thread::current();
2864 HandleMark hm(thread);
2865 BytecodeStream s(methodHandle(thread, m));
2866 Bytecodes::Code c;
2867 while ((c = s.next()) >= 0) {
2868 _number_of_bytecodes++;
2869 _bytecodes_profile[c]++;
2870 }
2871 }
2872 }
2874 public:
2875 static void print() {
2876 initialize();
2877 SystemDictionary::methods_do(do_method);
2878 // generate output
2879 tty->cr();
2880 tty->print_cr("Method statistics (static):");
2881 // flag distribution
2882 tty->cr();
2883 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2884 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2885 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2886 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2887 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2888 // parameter size profile
2889 tty->cr();
2890 { int tot = 0;
2891 int avg = 0;
2892 for (int i = 0; i < max_parameter_size; i++) {
2893 int n = _parameter_size_profile[i];
2894 tot += n;
2895 avg += n*i;
2896 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2897 }
2898 assert(tot == _number_of_methods, "should be the same");
2899 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2900 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2901 }
2902 // bytecodes profile
2903 tty->cr();
2904 { int tot = 0;
2905 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2906 if (Bytecodes::is_defined(i)) {
2907 Bytecodes::Code c = Bytecodes::cast(i);
2908 int n = _bytecodes_profile[c];
2909 tot += n;
2910 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2911 }
2912 }
2913 assert(tot == _number_of_bytecodes, "should be the same");
2914 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2915 }
2916 tty->cr();
2917 }
2918 };
2920 int MethodStatistics::_number_of_methods;
2921 int MethodStatistics::_number_of_final_methods;
2922 int MethodStatistics::_number_of_static_methods;
2923 int MethodStatistics::_number_of_native_methods;
2924 int MethodStatistics::_number_of_synchronized_methods;
2925 int MethodStatistics::_number_of_profiled_methods;
2926 int MethodStatistics::_number_of_bytecodes;
2927 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2928 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2931 void SystemDictionary::print_method_statistics() {
2932 MethodStatistics::print();
2933 }
2935 #endif // PRODUCT