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 */
24
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 #if INCLUDE_JFR
42 #include "jfr/jfrEvents.hpp"
43 #include "jfr/jni/jfrUpcalls.hpp"
44 #endif
45 #include "memory/filemap.hpp"
46 #include "memory/gcLocker.hpp"
47 #include "memory/oopFactory.hpp"
48 #include "oops/instanceKlass.hpp"
49 #include "oops/instanceRefKlass.hpp"
50 #include "oops/klass.inline.hpp"
51 #include "oops/methodData.hpp"
52 #include "oops/objArrayKlass.hpp"
53 #include "oops/oop.inline.hpp"
54 #include "oops/oop.inline2.hpp"
55 #include "oops/typeArrayKlass.hpp"
56 #include "prims/jvmtiEnvBase.hpp"
57 #include "prims/methodHandles.hpp"
58 #include "runtime/arguments.hpp"
59 #include "runtime/biasedLocking.hpp"
60 #include "runtime/fieldType.hpp"
61 #include "runtime/handles.inline.hpp"
62 #include "runtime/java.hpp"
63 #include "runtime/javaCalls.hpp"
64 #include "runtime/mutexLocker.hpp"
65 #include "runtime/orderAccess.inline.hpp"
66 #include "runtime/signature.hpp"
67 #include "services/classLoadingService.hpp"
68 #include "services/threadService.hpp"
69 #include "utilities/macros.hpp"
70 #include "utilities/ticks.hpp"
71
72 Dictionary* SystemDictionary::_dictionary = NULL;
73 PlaceholderTable* SystemDictionary::_placeholders = NULL;
74 Dictionary* SystemDictionary::_shared_dictionary = NULL;
75 LoaderConstraintTable* SystemDictionary::_loader_constraints = NULL;
76 ResolutionErrorTable* SystemDictionary::_resolution_errors = NULL;
77 SymbolPropertyTable* SystemDictionary::_invoke_method_table = NULL;
78
79
80 int SystemDictionary::_number_of_modifications = 0;
81 int SystemDictionary::_sdgeneration = 0;
82 const int SystemDictionary::_primelist[_prime_array_size] = {1009,2017,4049,5051,10103,
83 20201,40423,99991};
84
85 oop SystemDictionary::_system_loader_lock_obj = NULL;
86
87 Klass* SystemDictionary::_well_known_klasses[SystemDictionary::WKID_LIMIT]
88 = { NULL /*, NULL...*/ };
89
90 Klass* SystemDictionary::_box_klasses[T_VOID+1] = { NULL /*, NULL...*/ };
91
92 oop SystemDictionary::_java_system_loader = NULL;
93
94 bool SystemDictionary::_has_loadClassInternal = false;
95 bool SystemDictionary::_has_checkPackageAccess = false;
96
97 // lazily initialized klass variables
98 Klass* volatile SystemDictionary::_abstract_ownable_synchronizer_klass = NULL;
99
100 #if INCLUDE_JFR
101 static const Symbol* jfr_event_handler_proxy = NULL;
102 #endif // INCLUDE_JFR
103
104 // ----------------------------------------------------------------------------
105 // Java-level SystemLoader
106
107 oop SystemDictionary::java_system_loader() {
108 return _java_system_loader;
109 }
110
111 void SystemDictionary::compute_java_system_loader(TRAPS) {
112 KlassHandle system_klass(THREAD, WK_KLASS(ClassLoader_klass));
113 JavaValue result(T_OBJECT);
114 JavaCalls::call_static(&result,
115 KlassHandle(THREAD, WK_KLASS(ClassLoader_klass)),
116 vmSymbols::getSystemClassLoader_name(),
117 vmSymbols::void_classloader_signature(),
118 CHECK);
119
120 _java_system_loader = (oop)result.get_jobject();
121
122 CDS_ONLY(SystemDictionaryShared::initialize(CHECK);)
123 }
124
125
126 ClassLoaderData* SystemDictionary::register_loader(Handle class_loader, TRAPS) {
127 if (class_loader() == NULL) return ClassLoaderData::the_null_class_loader_data();
128 return ClassLoaderDataGraph::find_or_create(class_loader, THREAD);
129 }
130
131 // ----------------------------------------------------------------------------
132 // debugging
133
134 #ifdef ASSERT
135
136 // return true if class_name contains no '.' (internal format is '/')
137 bool SystemDictionary::is_internal_format(Symbol* class_name) {
138 if (class_name != NULL) {
139 ResourceMark rm;
140 char* name = class_name->as_C_string();
141 return strchr(name, '.') == NULL;
142 } else {
143 return true;
144 }
145 }
146
147 #endif
148 #if INCLUDE_JFR
149 #include "jfr/jfr.hpp"
150 #endif
151
152 // ----------------------------------------------------------------------------
153 // Parallel class loading check
154
155 bool SystemDictionary::is_parallelCapable(Handle class_loader) {
156 if (UnsyncloadClass || class_loader.is_null()) return true;
157 if (AlwaysLockClassLoader) return false;
158 return java_lang_ClassLoader::parallelCapable(class_loader());
159 }
160 // ----------------------------------------------------------------------------
161 // ParallelDefineClass flag does not apply to bootclass loader
162 bool SystemDictionary::is_parallelDefine(Handle class_loader) {
163 if (class_loader.is_null()) return false;
164 if (AllowParallelDefineClass && java_lang_ClassLoader::parallelCapable(class_loader())) {
165 return true;
166 }
167 return false;
168 }
169
170 /**
171 * Returns true if the passed class loader is the extension class loader.
172 */
173 bool SystemDictionary::is_ext_class_loader(Handle class_loader) {
174 if (class_loader.is_null()) {
175 return false;
176 }
177 return (class_loader->klass()->name() == vmSymbols::sun_misc_Launcher_ExtClassLoader());
178 }
179
180 // ----------------------------------------------------------------------------
181 // Resolving of classes
182
183 // Forwards to resolve_or_null
184
185 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, TRAPS) {
186 Klass* klass = resolve_or_null(class_name, class_loader, protection_domain, THREAD);
187 if (HAS_PENDING_EXCEPTION || klass == NULL) {
188 KlassHandle k_h(THREAD, klass);
189 // can return a null klass
190 klass = handle_resolution_exception(class_name, class_loader, protection_domain, throw_error, k_h, THREAD);
191 }
192 return klass;
193 }
194
195 Klass* SystemDictionary::handle_resolution_exception(Symbol* class_name, Handle class_loader, Handle protection_domain, bool throw_error, KlassHandle klass_h, TRAPS) {
196 if (HAS_PENDING_EXCEPTION) {
197 // If we have a pending exception we forward it to the caller, unless throw_error is true,
198 // in which case we have to check whether the pending exception is a ClassNotFoundException,
199 // and if so convert it to a NoClassDefFoundError
200 // And chain the original ClassNotFoundException
201 if (throw_error && PENDING_EXCEPTION->is_a(SystemDictionary::ClassNotFoundException_klass())) {
202 ResourceMark rm(THREAD);
203 assert(klass_h() == NULL, "Should not have result with exception pending");
204 Handle e(THREAD, PENDING_EXCEPTION);
205 CLEAR_PENDING_EXCEPTION;
206 THROW_MSG_CAUSE_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string(), e);
207 } else {
208 return NULL;
209 }
210 }
211 // Class not found, throw appropriate error or exception depending on value of throw_error
212 if (klass_h() == NULL) {
213 ResourceMark rm(THREAD);
214 if (throw_error) {
215 THROW_MSG_NULL(vmSymbols::java_lang_NoClassDefFoundError(), class_name->as_C_string());
216 } else {
217 THROW_MSG_NULL(vmSymbols::java_lang_ClassNotFoundException(), class_name->as_C_string());
218 }
219 }
220 return (Klass*)klass_h();
221 }
222
223
224 Klass* SystemDictionary::resolve_or_fail(Symbol* class_name,
225 bool throw_error, TRAPS)
226 {
227 return resolve_or_fail(class_name, Handle(), Handle(), throw_error, THREAD);
228 }
229
230
231 // Forwards to resolve_instance_class_or_null
232
233 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, Handle class_loader, Handle protection_domain, TRAPS) {
234 assert(!THREAD->is_Compiler_thread(),
235 err_msg("can not load classes with compiler thread: class=%s, classloader=%s",
236 class_name->as_C_string(),
237 class_loader.is_null() ? "null" : class_loader->klass()->name()->as_C_string()));
238 if (FieldType::is_array(class_name)) {
239 return resolve_array_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
240 } else if (FieldType::is_obj(class_name)) {
241 ResourceMark rm(THREAD);
242 // Ignore wrapping L and ;.
243 TempNewSymbol name = SymbolTable::new_symbol(class_name->as_C_string() + 1,
244 class_name->utf8_length() - 2, CHECK_NULL);
245 return resolve_instance_class_or_null(name, class_loader, protection_domain, CHECK_NULL);
246 } else {
247 return resolve_instance_class_or_null(class_name, class_loader, protection_domain, CHECK_NULL);
248 }
249 }
250
251 Klass* SystemDictionary::resolve_or_null(Symbol* class_name, TRAPS) {
252 return resolve_or_null(class_name, Handle(), Handle(), THREAD);
253 }
254
255 // Forwards to resolve_instance_class_or_null
256
257 Klass* SystemDictionary::resolve_array_class_or_null(Symbol* class_name,
258 Handle class_loader,
259 Handle protection_domain,
260 TRAPS) {
261 assert(FieldType::is_array(class_name), "must be array");
262 Klass* k = NULL;
263 FieldArrayInfo fd;
264 // dimension and object_key in FieldArrayInfo are assigned as a side-effect
265 // of this call
266 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_NULL);
267 if (t == T_OBJECT) {
268 // naked oop "k" is OK here -- we assign back into it
269 k = SystemDictionary::resolve_instance_class_or_null(fd.object_key(),
270 class_loader,
271 protection_domain,
272 CHECK_NULL);
273 if (k != NULL) {
274 k = k->array_klass(fd.dimension(), CHECK_NULL);
275 }
276 } else {
277 k = Universe::typeArrayKlassObj(t);
278 k = TypeArrayKlass::cast(k)->array_klass(fd.dimension(), CHECK_NULL);
279 }
280 return k;
281 }
282
283
284 // Must be called for any super-class or super-interface resolution
285 // during class definition to allow class circularity checking
286 // super-interface callers:
287 // parse_interfaces - for defineClass & jvmtiRedefineClasses
288 // super-class callers:
289 // ClassFileParser - for defineClass & jvmtiRedefineClasses
290 // load_shared_class - while loading a class from shared archive
291 // resolve_instance_class_or_null:
292 // via: handle_parallel_super_load
293 // when resolving a class that has an existing placeholder with
294 // a saved superclass [i.e. a defineClass is currently in progress]
295 // if another thread is trying to resolve the class, it must do
296 // super-class checks on its own thread to catch class circularity
297 // This last call is critical in class circularity checking for cases
298 // where classloading is delegated to different threads and the
299 // classloader lock is released.
300 // Take the case: Base->Super->Base
301 // 1. If thread T1 tries to do a defineClass of class Base
302 // resolve_super_or_fail creates placeholder: T1, Base (super Super)
303 // 2. resolve_instance_class_or_null does not find SD or placeholder for Super
304 // so it tries to load Super
305 // 3. If we load the class internally, or user classloader uses same thread
306 // loadClassFromxxx or defineClass via parseClassFile Super ...
307 // 3.1 resolve_super_or_fail creates placeholder: T1, Super (super Base)
308 // 3.3 resolve_instance_class_or_null Base, finds placeholder for Base
309 // 3.4 calls resolve_super_or_fail Base
310 // 3.5 finds T1,Base -> throws class circularity
311 //OR 4. If T2 tries to resolve Super via defineClass Super ...
312 // 4.1 resolve_super_or_fail creates placeholder: T2, Super (super Base)
313 // 4.2 resolve_instance_class_or_null Base, finds placeholder for Base (super Super)
314 // 4.3 calls resolve_super_or_fail Super in parallel on own thread T2
315 // 4.4 finds T2, Super -> throws class circularity
316 // Must be called, even if superclass is null, since this is
317 // where the placeholder entry is created which claims this
318 // thread is loading this class/classloader.
319 Klass* SystemDictionary::resolve_super_or_fail(Symbol* child_name,
320 Symbol* class_name,
321 Handle class_loader,
322 Handle protection_domain,
323 bool is_superclass,
324 TRAPS) {
325 // Double-check, if child class is already loaded, just return super-class,interface
326 // Don't add a placedholder if already loaded, i.e. already in system dictionary
327 // Make sure there's a placeholder for the *child* before resolving.
328 // Used as a claim that this thread is currently loading superclass/classloader
329 // Used here for ClassCircularity checks and also for heap verification
330 // (every InstanceKlass in the heap needs to be in the system dictionary
331 // or have a placeholder).
332 // Must check ClassCircularity before checking if super class is already loaded
333 //
334 // We might not already have a placeholder if this child_name was
335 // first seen via resolve_from_stream (jni_DefineClass or JVM_DefineClass);
336 // the name of the class might not be known until the stream is actually
337 // parsed.
338 // Bugs 4643874, 4715493
339 // compute_hash can have a safepoint
340
341 ClassLoaderData* loader_data = class_loader_data(class_loader);
342 unsigned int d_hash = dictionary()->compute_hash(child_name, loader_data);
343 int d_index = dictionary()->hash_to_index(d_hash);
344 unsigned int p_hash = placeholders()->compute_hash(child_name, loader_data);
345 int p_index = placeholders()->hash_to_index(p_hash);
346 // can't throw error holding a lock
347 bool child_already_loaded = false;
348 bool throw_circularity_error = false;
349 {
350 MutexLocker mu(SystemDictionary_lock, THREAD);
351 Klass* childk = find_class(d_index, d_hash, child_name, loader_data);
352 Klass* quicksuperk;
353 // to support // loading: if child done loading, just return superclass
354 // if class_name, & class_loader don't match:
355 // if initial define, SD update will give LinkageError
356 // if redefine: compare_class_versions will give HIERARCHY_CHANGED
357 // so we don't throw an exception here.
358 // see: nsk redefclass014 & java.lang.instrument Instrument032
359 if ((childk != NULL ) && (is_superclass) &&
360 ((quicksuperk = InstanceKlass::cast(childk)->super()) != NULL) &&
361
362 ((quicksuperk->name() == class_name) &&
363 (quicksuperk->class_loader() == class_loader()))) {
364 return quicksuperk;
365 } else {
366 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, child_name, loader_data);
367 if (probe && probe->check_seen_thread(THREAD, PlaceholderTable::LOAD_SUPER)) {
368 throw_circularity_error = true;
369 }
370 }
371 if (!throw_circularity_error) {
372 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, class_name, THREAD);
373 }
374 }
375 if (throw_circularity_error) {
376 ResourceMark rm(THREAD);
377 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), child_name->as_C_string());
378 }
379
380 // java.lang.Object should have been found above
381 assert(class_name != NULL, "null super class for resolving");
382 // Resolve the super class or interface, check results on return
383 Klass* superk = SystemDictionary::resolve_or_null(class_name,
384 class_loader,
385 protection_domain,
386 THREAD);
387
388 KlassHandle superk_h(THREAD, superk);
389
390 // Clean up of placeholders moved so that each classloadAction registrar self-cleans up
391 // It is no longer necessary to keep the placeholder table alive until update_dictionary
392 // or error. GC used to walk the placeholder table as strong roots.
393 // The instanceKlass is kept alive because the class loader is on the stack,
394 // which keeps the loader_data alive, as well as all instanceKlasses in
395 // the loader_data. parseClassFile adds the instanceKlass to loader_data.
396 {
397 MutexLocker mu(SystemDictionary_lock, THREAD);
398 placeholders()->find_and_remove(p_index, p_hash, child_name, loader_data, PlaceholderTable::LOAD_SUPER, THREAD);
399 SystemDictionary_lock->notify_all();
400 }
401 if (HAS_PENDING_EXCEPTION || superk_h() == NULL) {
402 // can null superk
403 superk_h = KlassHandle(THREAD, handle_resolution_exception(class_name, class_loader, protection_domain, true, superk_h, THREAD));
404 }
405
406 return superk_h();
407 }
408
409 void SystemDictionary::validate_protection_domain(instanceKlassHandle klass,
410 Handle class_loader,
411 Handle protection_domain,
412 TRAPS) {
413 if(!has_checkPackageAccess()) return;
414
415 // Now we have to call back to java to check if the initating class has access
416 JavaValue result(T_VOID);
417 if (TraceProtectionDomainVerification) {
418 // Print out trace information
419 tty->print_cr("Checking package access");
420 tty->print(" - class loader: "); class_loader()->print_value_on(tty); tty->cr();
421 tty->print(" - protection domain: "); protection_domain()->print_value_on(tty); tty->cr();
422 tty->print(" - loading: "); klass()->print_value_on(tty); tty->cr();
423 }
424
425 KlassHandle system_loader(THREAD, SystemDictionary::ClassLoader_klass());
426 JavaCalls::call_special(&result,
427 class_loader,
428 system_loader,
429 vmSymbols::checkPackageAccess_name(),
430 vmSymbols::class_protectiondomain_signature(),
431 Handle(THREAD, klass->java_mirror()),
432 protection_domain,
433 THREAD);
434
435 if (TraceProtectionDomainVerification) {
436 if (HAS_PENDING_EXCEPTION) {
437 tty->print_cr(" -> DENIED !!!!!!!!!!!!!!!!!!!!!");
438 } else {
439 tty->print_cr(" -> granted");
440 }
441 tty->cr();
442 }
443
444 if (HAS_PENDING_EXCEPTION) return;
445
446 // If no exception has been thrown, we have validated the protection domain
447 // Insert the protection domain of the initiating class into the set.
448 {
449 // We recalculate the entry here -- we've called out to java since
450 // the last time it was calculated.
451 ClassLoaderData* loader_data = class_loader_data(class_loader);
452
453 Symbol* kn = klass->name();
454 unsigned int d_hash = dictionary()->compute_hash(kn, loader_data);
455 int d_index = dictionary()->hash_to_index(d_hash);
456
457 MutexLocker mu(SystemDictionary_lock, THREAD);
458 {
459 // Note that we have an entry, and entries can be deleted only during GC,
460 // so we cannot allow GC to occur while we're holding this entry.
461
462 // We're using a No_Safepoint_Verifier to catch any place where we
463 // might potentially do a GC at all.
464 // Dictionary::do_unloading() asserts that classes in SD are only
465 // unloaded at a safepoint. Anonymous classes are not in SD.
466 No_Safepoint_Verifier nosafepoint;
467 dictionary()->add_protection_domain(d_index, d_hash, klass, loader_data,
468 protection_domain, THREAD);
469 }
470 }
471 }
472
473 // We only get here if this thread finds that another thread
474 // has already claimed the placeholder token for the current operation,
475 // but that other thread either never owned or gave up the
476 // object lock
477 // Waits on SystemDictionary_lock to indicate placeholder table updated
478 // On return, caller must recheck placeholder table state
479 //
480 // We only get here if
481 // 1) custom classLoader, i.e. not bootstrap classloader
482 // 2) UnsyncloadClass not set
483 // 3) custom classLoader has broken the class loader objectLock
484 // so another thread got here in parallel
485 //
486 // lockObject must be held.
487 // Complicated dance due to lock ordering:
488 // Must first release the classloader object lock to
489 // allow initial definer to complete the class definition
490 // and to avoid deadlock
491 // Reclaim classloader lock object with same original recursion count
492 // Must release SystemDictionary_lock after notify, since
493 // class loader lock must be claimed before SystemDictionary_lock
494 // to prevent deadlocks
495 //
496 // The notify allows applications that did an untimed wait() on
497 // the classloader object lock to not hang.
498 void SystemDictionary::double_lock_wait(Handle lockObject, TRAPS) {
499 assert_lock_strong(SystemDictionary_lock);
500
501 bool calledholdinglock
502 = ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD, lockObject);
503 assert(calledholdinglock,"must hold lock for notify");
504 assert((!(lockObject() == _system_loader_lock_obj) && !is_parallelCapable(lockObject)), "unexpected double_lock_wait");
505 ObjectSynchronizer::notifyall(lockObject, THREAD);
506 intptr_t recursions = ObjectSynchronizer::complete_exit(lockObject, THREAD);
507 SystemDictionary_lock->wait();
508 SystemDictionary_lock->unlock();
509 ObjectSynchronizer::reenter(lockObject, recursions, THREAD);
510 SystemDictionary_lock->lock();
511 }
512
513 // If the class in is in the placeholder table, class loading is in progress
514 // For cases where the application changes threads to load classes, it
515 // is critical to ClassCircularity detection that we try loading
516 // the superclass on the same thread internally, so we do parallel
517 // super class loading here.
518 // This also is critical in cases where the original thread gets stalled
519 // even in non-circularity situations.
520 // Note: must call resolve_super_or_fail even if null super -
521 // to force placeholder entry creation for this class for circularity detection
522 // Caller must check for pending exception
523 // Returns non-null Klass* if other thread has completed load
524 // and we are done,
525 // If return null Klass* and no pending exception, the caller must load the class
526 instanceKlassHandle SystemDictionary::handle_parallel_super_load(
527 Symbol* name, Symbol* superclassname, Handle class_loader,
528 Handle protection_domain, Handle lockObject, TRAPS) {
529
530 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
531 ClassLoaderData* loader_data = class_loader_data(class_loader);
532 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
533 int d_index = dictionary()->hash_to_index(d_hash);
534 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
535 int p_index = placeholders()->hash_to_index(p_hash);
536
537 // superk is not used, resolve_super called for circularity check only
538 // This code is reached in two situations. One if this thread
539 // is loading the same class twice (e.g. ClassCircularity, or
540 // java.lang.instrument).
541 // The second is if another thread started the resolve_super first
542 // and has not yet finished.
543 // In both cases the original caller will clean up the placeholder
544 // entry on error.
545 Klass* superk = SystemDictionary::resolve_super_or_fail(name,
546 superclassname,
547 class_loader,
548 protection_domain,
549 true,
550 CHECK_(nh));
551
552 // parallelCapable class loaders do NOT wait for parallel superclass loads to complete
553 // Serial class loaders and bootstrap classloader do wait for superclass loads
554 if (!class_loader.is_null() && is_parallelCapable(class_loader)) {
555 MutexLocker mu(SystemDictionary_lock, THREAD);
556 // Check if classloading completed while we were loading superclass or waiting
557 Klass* check = find_class(d_index, d_hash, name, loader_data);
558 if (check != NULL) {
559 // Klass is already loaded, so just return it
560 return(instanceKlassHandle(THREAD, check));
561 } else {
562 return nh;
563 }
564 }
565
566 // must loop to both handle other placeholder updates
567 // and spurious notifications
568 bool super_load_in_progress = true;
569 PlaceholderEntry* placeholder;
570 while (super_load_in_progress) {
571 MutexLocker mu(SystemDictionary_lock, THREAD);
572 // Check if classloading completed while we were loading superclass or waiting
573 Klass* check = find_class(d_index, d_hash, name, loader_data);
574 if (check != NULL) {
575 // Klass is already loaded, so just return it
576 return(instanceKlassHandle(THREAD, check));
577 } else {
578 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
579 if (placeholder && placeholder->super_load_in_progress() ){
580 // Before UnsyncloadClass:
581 // We only get here if the application has released the
582 // classloader lock when another thread was in the middle of loading a
583 // superclass/superinterface for this class, and now
584 // this thread is also trying to load this class.
585 // To minimize surprises, the first thread that started to
586 // load a class should be the one to complete the loading
587 // with the classfile it initially expected.
588 // This logic has the current thread wait once it has done
589 // all the superclass/superinterface loading it can, until
590 // the original thread completes the class loading or fails
591 // If it completes we will use the resulting InstanceKlass
592 // which we will find below in the systemDictionary.
593 // We also get here for parallel bootstrap classloader
594 if (class_loader.is_null()) {
595 SystemDictionary_lock->wait();
596 } else {
597 double_lock_wait(lockObject, THREAD);
598 }
599 } else {
600 // If not in SD and not in PH, other thread's load must have failed
601 super_load_in_progress = false;
602 }
603 }
604 }
605 return (nh);
606 }
607
608 #if INCLUDE_JFR
609 // utility function for class load event
610 static void post_class_load_event(EventClassLoad &event,
611 instanceKlassHandle k,
612 Handle initiating_loader) {
613 if (event.should_commit()) {
614 event.set_loadedClass(k());
615 event.set_definingClassLoader(k->class_loader_data());
616 oop class_loader = initiating_loader.is_null() ? (oop)NULL : initiating_loader();
617 event.set_initiatingClassLoader(class_loader != NULL ?
618 ClassLoaderData::class_loader_data_or_null(class_loader) :
619 (ClassLoaderData*)NULL);
620 event.commit();
621 }
622 }
623 #endif // INCLUDE_JFR
624
625 Klass* SystemDictionary::resolve_instance_class_or_null(Symbol* name,
626 Handle class_loader,
627 Handle protection_domain,
628 TRAPS) {
629 assert(name != NULL && !FieldType::is_array(name) &&
630 !FieldType::is_obj(name), "invalid class name");
631
632 #if INCLUDE_JFR
633 EventClassLoad class_load_start_event;
634 #endif
635
636 // UseNewReflection
637 // Fix for 4474172; see evaluation for more details
638 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
639 ClassLoaderData *loader_data = register_loader(class_loader, CHECK_NULL);
640
641 // Do lookup to see if class already exist and the protection domain
642 // has the right access
643 // This call uses find which checks protection domain already matches
644 // All subsequent calls use find_class, and set has_loaded_class so that
645 // before we return a result we call out to java to check for valid protection domain
646 // to allow returning the Klass* and add it to the pd_set if it is valid
647 unsigned int d_hash = dictionary()->compute_hash(name, loader_data);
648 int d_index = dictionary()->hash_to_index(d_hash);
649 Klass* probe = dictionary()->find(d_index, d_hash, name, loader_data,
650 protection_domain, THREAD);
651 if (probe != NULL) return probe;
652
653
654 // Non-bootstrap class loaders will call out to class loader and
655 // define via jvm/jni_DefineClass which will acquire the
656 // class loader object lock to protect against multiple threads
657 // defining the class in parallel by accident.
658 // This lock must be acquired here so the waiter will find
659 // any successful result in the SystemDictionary and not attempt
660 // the define
661 // ParallelCapable Classloaders and the bootstrap classloader,
662 // or all classloaders with UnsyncloadClass do not acquire lock here
663 bool DoObjectLock = true;
664 if (is_parallelCapable(class_loader)) {
665 DoObjectLock = false;
666 }
667
668 unsigned int p_hash = placeholders()->compute_hash(name, loader_data);
669 int p_index = placeholders()->hash_to_index(p_hash);
670
671 // Class is not in SystemDictionary so we have to do loading.
672 // Make sure we are synchronized on the class loader before we proceed
673 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
674 check_loader_lock_contention(lockObject, THREAD);
675 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
676
677 // Check again (after locking) if class already exist in SystemDictionary
678 bool class_has_been_loaded = false;
679 bool super_load_in_progress = false;
680 bool havesupername = false;
681 instanceKlassHandle k;
682 PlaceholderEntry* placeholder;
683 Symbol* superclassname = NULL;
684
685 {
686 MutexLocker mu(SystemDictionary_lock, THREAD);
687 Klass* check = find_class(d_index, d_hash, name, loader_data);
688 if (check != NULL) {
689 // Klass is already loaded, so just return it
690 class_has_been_loaded = true;
691 k = instanceKlassHandle(THREAD, check);
692 } else {
693 placeholder = placeholders()->get_entry(p_index, p_hash, name, loader_data);
694 if (placeholder && placeholder->super_load_in_progress()) {
695 super_load_in_progress = true;
696 if (placeholder->havesupername() == true) {
697 superclassname = placeholder->supername();
698 havesupername = true;
699 }
700 }
701 }
702 }
703
704 // If the class is in the placeholder table, class loading is in progress
705 if (super_load_in_progress && havesupername==true) {
706 k = SystemDictionary::handle_parallel_super_load(name, superclassname,
707 class_loader, protection_domain, lockObject, THREAD);
708 if (HAS_PENDING_EXCEPTION) {
709 return NULL;
710 }
711 if (!k.is_null()) {
712 class_has_been_loaded = true;
713 }
714 }
715
716 bool throw_circularity_error = false;
717 if (!class_has_been_loaded) {
718 bool load_instance_added = false;
719
720 // add placeholder entry to record loading instance class
721 // Five cases:
722 // All cases need to prevent modifying bootclasssearchpath
723 // in parallel with a classload of same classname
724 // Redefineclasses uses existence of the placeholder for the duration
725 // of the class load to prevent concurrent redefinition of not completely
726 // defined classes.
727 // case 1. traditional classloaders that rely on the classloader object lock
728 // - no other need for LOAD_INSTANCE
729 // case 2. traditional classloaders that break the classloader object lock
730 // as a deadlock workaround. Detection of this case requires that
731 // this check is done while holding the classloader object lock,
732 // and that lock is still held when calling classloader's loadClass.
733 // For these classloaders, we ensure that the first requestor
734 // completes the load and other requestors wait for completion.
735 // case 3. UnsyncloadClass - don't use objectLocker
736 // With this flag, we allow parallel classloading of a
737 // class/classloader pair
738 // case4. Bootstrap classloader - don't own objectLocker
739 // This classloader supports parallelism at the classloader level,
740 // but only allows a single load of a class/classloader pair.
741 // No performance benefit and no deadlock issues.
742 // case 5. parallelCapable user level classloaders - without objectLocker
743 // Allow parallel classloading of a class/classloader pair
744
745 {
746 MutexLocker mu(SystemDictionary_lock, THREAD);
747 if (class_loader.is_null() || !is_parallelCapable(class_loader)) {
748 PlaceholderEntry* oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
749 if (oldprobe) {
750 // only need check_seen_thread once, not on each loop
751 // 6341374 java/lang/Instrument with -Xcomp
752 if (oldprobe->check_seen_thread(THREAD, PlaceholderTable::LOAD_INSTANCE)) {
753 throw_circularity_error = true;
754 } else {
755 // case 1: traditional: should never see load_in_progress.
756 while (!class_has_been_loaded && oldprobe && oldprobe->instance_load_in_progress()) {
757
758 // case 4: bootstrap classloader: prevent futile classloading,
759 // wait on first requestor
760 if (class_loader.is_null()) {
761 SystemDictionary_lock->wait();
762 } else {
763 // case 2: traditional with broken classloader lock. wait on first
764 // requestor.
765 double_lock_wait(lockObject, THREAD);
766 }
767 // Check if classloading completed while we were waiting
768 Klass* check = find_class(d_index, d_hash, name, loader_data);
769 if (check != NULL) {
770 // Klass is already loaded, so just return it
771 k = instanceKlassHandle(THREAD, check);
772 class_has_been_loaded = true;
773 }
774 // check if other thread failed to load and cleaned up
775 oldprobe = placeholders()->get_entry(p_index, p_hash, name, loader_data);
776 }
777 }
778 }
779 }
780 // All cases: add LOAD_INSTANCE holding SystemDictionary_lock
781 // case 3: UnsyncloadClass || case 5: parallelCapable: allow competing threads to try
782 // LOAD_INSTANCE in parallel
783
784 if (!throw_circularity_error && !class_has_been_loaded) {
785 PlaceholderEntry* newprobe = placeholders()->find_and_add(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, NULL, THREAD);
786 load_instance_added = true;
787 // For class loaders that do not acquire the classloader object lock,
788 // if they did not catch another thread holding LOAD_INSTANCE,
789 // need a check analogous to the acquire ObjectLocker/find_class
790 // i.e. now that we hold the LOAD_INSTANCE token on loading this class/CL
791 // one final check if the load has already completed
792 // class loaders holding the ObjectLock shouldn't find the class here
793 Klass* check = find_class(d_index, d_hash, name, loader_data);
794 if (check != NULL) {
795 // Klass is already loaded, so return it after checking/adding protection domain
796 k = instanceKlassHandle(THREAD, check);
797 class_has_been_loaded = true;
798 }
799 }
800 }
801
802 // must throw error outside of owning lock
803 if (throw_circularity_error) {
804 assert(!HAS_PENDING_EXCEPTION && load_instance_added == false,"circularity error cleanup");
805 ResourceMark rm(THREAD);
806 THROW_MSG_NULL(vmSymbols::java_lang_ClassCircularityError(), name->as_C_string());
807 }
808
809 if (!class_has_been_loaded) {
810
811 // Do actual loading
812 k = load_instance_class(name, class_loader, THREAD);
813
814 // For UnsyncloadClass only
815 // If they got a linkageError, check if a parallel class load succeeded.
816 // If it did, then for bytecode resolution the specification requires
817 // that we return the same result we did for the other thread, i.e. the
818 // successfully loaded InstanceKlass
819 // Should not get here for classloaders that support parallelism
820 // with the new cleaner mechanism, even with AllowParallelDefineClass
821 // Bootstrap goes through here to allow for an extra guarantee check
822 if (UnsyncloadClass || (class_loader.is_null())) {
823 if (k.is_null() && HAS_PENDING_EXCEPTION
824 && PENDING_EXCEPTION->is_a(SystemDictionary::LinkageError_klass())) {
825 MutexLocker mu(SystemDictionary_lock, THREAD);
826 Klass* check = find_class(d_index, d_hash, name, loader_data);
827 if (check != NULL) {
828 // Klass is already loaded, so just use it
829 k = instanceKlassHandle(THREAD, check);
830 CLEAR_PENDING_EXCEPTION;
831 guarantee((!class_loader.is_null()), "dup definition for bootstrap loader?");
832 }
833 }
834 }
835
836 // If everything was OK (no exceptions, no null return value), and
837 // class_loader is NOT the defining loader, do a little more bookkeeping.
838 if (!HAS_PENDING_EXCEPTION && !k.is_null() &&
839 k->class_loader() != class_loader()) {
840
841 check_constraints(d_index, d_hash, k, class_loader, false, THREAD);
842
843 // Need to check for a PENDING_EXCEPTION again; check_constraints
844 // can throw but we may have to remove entry from the placeholder table below.
845 if (!HAS_PENDING_EXCEPTION) {
846 // Record dependency for non-parent delegation.
847 // This recording keeps the defining class loader of the klass (k) found
848 // from being unloaded while the initiating class loader is loaded
849 // even if the reference to the defining class loader is dropped
850 // before references to the initiating class loader.
851 loader_data->record_dependency(k(), THREAD);
852 }
853
854 if (!HAS_PENDING_EXCEPTION) {
855 { // Grabbing the Compile_lock prevents systemDictionary updates
856 // during compilations.
857 MutexLocker mu(Compile_lock, THREAD);
858 update_dictionary(d_index, d_hash, p_index, p_hash,
859 k, class_loader, THREAD);
860 }
861
862 if (JvmtiExport::should_post_class_load()) {
863 Thread *thread = THREAD;
864 assert(thread->is_Java_thread(), "thread->is_Java_thread()");
865 JvmtiExport::post_class_load((JavaThread *) thread, k());
866 }
867 }
868 }
869 } // load_instance_class loop
870
871 if (load_instance_added == true) {
872 // clean up placeholder entries for LOAD_INSTANCE success or error
873 // This brackets the SystemDictionary updates for both defining
874 // and initiating loaders
875 MutexLocker mu(SystemDictionary_lock, THREAD);
876 placeholders()->find_and_remove(p_index, p_hash, name, loader_data, PlaceholderTable::LOAD_INSTANCE, THREAD);
877 SystemDictionary_lock->notify_all();
878 }
879 }
880
881 if (HAS_PENDING_EXCEPTION || k.is_null()) {
882 return NULL;
883 }
884
885 #if INCLUDE_JFR
886 post_class_load_event(class_load_start_event, k, class_loader);
887 #endif
888
889 #ifdef ASSERT
890 {
891 ClassLoaderData* loader_data = k->class_loader_data();
892 MutexLocker mu(SystemDictionary_lock, THREAD);
893 Klass* kk = find_class(name, loader_data);
894 assert(kk == k(), "should be present in dictionary");
895 }
896 #endif
897
898 // return if the protection domain in NULL
899 if (protection_domain() == NULL) return k();
900
901 // Check the protection domain has the right access
902 {
903 MutexLocker mu(SystemDictionary_lock, THREAD);
904 // Note that we have an entry, and entries can be deleted only during GC,
905 // so we cannot allow GC to occur while we're holding this entry.
906 // We're using a No_Safepoint_Verifier to catch any place where we
907 // might potentially do a GC at all.
908 // Dictionary::do_unloading() asserts that classes in SD are only
909 // unloaded at a safepoint. Anonymous classes are not in SD.
910 No_Safepoint_Verifier nosafepoint;
911 if (dictionary()->is_valid_protection_domain(d_index, d_hash, name,
912 loader_data,
913 protection_domain)) {
914 return k();
915 }
916 }
917
918 // Verify protection domain. If it fails an exception is thrown
919 validate_protection_domain(k, class_loader, protection_domain, CHECK_NULL);
920
921 return k();
922 }
923
924
925 // This routine does not lock the system dictionary.
926 //
927 // Since readers don't hold a lock, we must make sure that system
928 // dictionary entries are only removed at a safepoint (when only one
929 // thread is running), and are added to in a safe way (all links must
930 // be updated in an MT-safe manner).
931 //
932 // Callers should be aware that an entry could be added just after
933 // _dictionary->bucket(index) is read here, so the caller will not see
934 // the new entry.
935
936 Klass* SystemDictionary::find(Symbol* class_name,
937 Handle class_loader,
938 Handle protection_domain,
939 TRAPS) {
940
941 // UseNewReflection
942 // The result of this call should be consistent with the result
943 // of the call to resolve_instance_class_or_null().
944 // See evaluation 6790209 and 4474172 for more details.
945 class_loader = Handle(THREAD, java_lang_ClassLoader::non_reflection_class_loader(class_loader()));
946 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data_or_null(class_loader());
947
948 if (loader_data == NULL) {
949 // If the ClassLoaderData has not been setup,
950 // then the class loader has no entries in the dictionary.
951 return NULL;
952 }
953
954 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
955 int d_index = dictionary()->hash_to_index(d_hash);
956
957 {
958 // Note that we have an entry, and entries can be deleted only during GC,
959 // so we cannot allow GC to occur while we're holding this entry.
960 // We're using a No_Safepoint_Verifier to catch any place where we
961 // might potentially do a GC at all.
962 // Dictionary::do_unloading() asserts that classes in SD are only
963 // unloaded at a safepoint. Anonymous classes are not in SD.
964 No_Safepoint_Verifier nosafepoint;
965 return dictionary()->find(d_index, d_hash, class_name, loader_data,
966 protection_domain, THREAD);
967 }
968 }
969
970
971 // Look for a loaded instance or array klass by name. Do not do any loading.
972 // return NULL in case of error.
973 Klass* SystemDictionary::find_instance_or_array_klass(Symbol* class_name,
974 Handle class_loader,
975 Handle protection_domain,
976 TRAPS) {
977 Klass* k = NULL;
978 assert(class_name != NULL, "class name must be non NULL");
979
980 if (FieldType::is_array(class_name)) {
981 // The name refers to an array. Parse the name.
982 // dimension and object_key in FieldArrayInfo are assigned as a
983 // side-effect of this call
984 FieldArrayInfo fd;
985 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
986 if (t != T_OBJECT) {
987 k = Universe::typeArrayKlassObj(t);
988 } else {
989 k = SystemDictionary::find(fd.object_key(), class_loader, protection_domain, THREAD);
990 }
991 if (k != NULL) {
992 k = k->array_klass_or_null(fd.dimension());
993 }
994 } else {
995 k = find(class_name, class_loader, protection_domain, THREAD);
996 }
997 return k;
998 }
999
1000 // Note: this method is much like resolve_from_stream, but
1001 // updates no supplemental data structures.
1002 // TODO consolidate the two methods with a helper routine?
1003 Klass* SystemDictionary::parse_stream(Symbol* class_name,
1004 Handle class_loader,
1005 Handle protection_domain,
1006 ClassFileStream* st,
1007 KlassHandle host_klass,
1008 GrowableArray<Handle>* cp_patches,
1009 TRAPS) {
1010 TempNewSymbol parsed_name = NULL;
1011
1012 #if INCLUDE_JFR
1013 EventClassLoad class_load_start_event;
1014 #endif
1015
1016 ClassLoaderData* loader_data;
1017 if (host_klass.not_null()) {
1018 // Create a new CLD for anonymous class, that uses the same class loader
1019 // as the host_klass
1020 assert(EnableInvokeDynamic, "");
1021 guarantee(host_klass->class_loader() == class_loader(), "should be the same");
1022 guarantee(!DumpSharedSpaces, "must not create anonymous classes when dumping");
1023 loader_data = ClassLoaderData::anonymous_class_loader_data(class_loader(), CHECK_NULL);
1024 loader_data->record_dependency(host_klass(), CHECK_NULL);
1025 } else {
1026 loader_data = ClassLoaderData::class_loader_data(class_loader());
1027 }
1028
1029 // Parse the stream. Note that we do this even though this klass might
1030 // already be present in the SystemDictionary, otherwise we would not
1031 // throw potential ClassFormatErrors.
1032 //
1033 // Note: "name" is updated.
1034
1035 instanceKlassHandle k = ClassFileParser(st).parseClassFile(class_name,
1036 loader_data,
1037 protection_domain,
1038 host_klass,
1039 cp_patches,
1040 parsed_name,
1041 true,
1042 THREAD);
1043
1044
1045 if (host_klass.not_null() && k.not_null()) {
1046 assert(EnableInvokeDynamic, "");
1047 // If it's anonymous, initialize it now, since nobody else will.
1048
1049 {
1050 MutexLocker mu_r(Compile_lock, THREAD);
1051
1052 // Add to class hierarchy, initialize vtables, and do possible
1053 // deoptimizations.
1054 add_to_hierarchy(k, CHECK_NULL); // No exception, but can block
1055
1056 // But, do not add to system dictionary.
1057
1058 // compiled code dependencies need to be validated anyway
1059 notice_modification();
1060 }
1061
1062 // Rewrite and patch constant pool here.
1063 k->link_class(CHECK_NULL);
1064 if (cp_patches != NULL) {
1065 k->constants()->patch_resolved_references(cp_patches);
1066 }
1067 k->eager_initialize(CHECK_NULL);
1068
1069 // notify jvmti
1070 if (JvmtiExport::should_post_class_load()) {
1071 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1072 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1073 }
1074
1075 #if INCLUDE_JFR
1076 post_class_load_event(class_load_start_event, k, class_loader);
1077 #endif
1078 }
1079 assert(host_klass.not_null() || cp_patches == NULL,
1080 "cp_patches only found with host_klass");
1081
1082 return k();
1083 }
1084
1085 // Add a klass to the system from a stream (called by jni_DefineClass and
1086 // JVM_DefineClass).
1087 // Note: class_name can be NULL. In that case we do not know the name of
1088 // the class until we have parsed the stream.
1089
1090 Klass* SystemDictionary::resolve_from_stream(Symbol* class_name,
1091 Handle class_loader,
1092 Handle protection_domain,
1093 ClassFileStream* st,
1094 bool verify,
1095 TRAPS) {
1096
1097 // Classloaders that support parallelism, e.g. bootstrap classloader,
1098 // or all classloaders with UnsyncloadClass do not acquire lock here
1099 bool DoObjectLock = true;
1100 if (is_parallelCapable(class_loader)) {
1101 DoObjectLock = false;
1102 }
1103
1104 ClassLoaderData* loader_data = register_loader(class_loader, CHECK_NULL);
1105
1106 // Make sure we are synchronized on the class loader before we proceed
1107 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1108 check_loader_lock_contention(lockObject, THREAD);
1109 ObjectLocker ol(lockObject, THREAD, DoObjectLock);
1110
1111 TempNewSymbol parsed_name = NULL;
1112
1113 // Parse the stream. Note that we do this even though this klass might
1114 // already be present in the SystemDictionary, otherwise we would not
1115 // throw potential ClassFormatErrors.
1116 //
1117 // Note: "name" is updated.
1118
1119 ClassFileParser parser(st);
1120 instanceKlassHandle k = parser.parseClassFile(class_name,
1121 loader_data,
1122 protection_domain,
1123 parsed_name,
1124 verify,
1125 THREAD);
1126
1127 const char* pkg = "java/";
1128 size_t pkglen = strlen(pkg);
1129 if (!HAS_PENDING_EXCEPTION &&
1130 !class_loader.is_null() &&
1131 parsed_name != NULL &&
1132 parsed_name->utf8_length() >= (int)pkglen &&
1133 !strncmp((const char*)parsed_name->bytes(), pkg, pkglen)) {
1134 // It is illegal to define classes in the "java." package from
1135 // JVM_DefineClass or jni_DefineClass unless you're the bootclassloader
1136 ResourceMark rm(THREAD);
1137 char* name = parsed_name->as_C_string();
1138 char* index = strrchr(name, '/');
1139 assert(index != NULL, "must be");
1140 *index = '\0'; // chop to just the package name
1141 while ((index = strchr(name, '/')) != NULL) {
1142 *index = '.'; // replace '/' with '.' in package name
1143 }
1144 const char* fmt = "Prohibited package name: %s";
1145 size_t len = strlen(fmt) + strlen(name);
1146 char* message = NEW_RESOURCE_ARRAY(char, len);
1147 jio_snprintf(message, len, fmt, name);
1148 Exceptions::_throw_msg(THREAD_AND_LOCATION,
1149 vmSymbols::java_lang_SecurityException(), message);
1150 }
1151
1152 if (!HAS_PENDING_EXCEPTION) {
1153 assert(parsed_name != NULL, "Sanity");
1154 assert(class_name == NULL || class_name == parsed_name, "name mismatch");
1155 // Verification prevents us from creating names with dots in them, this
1156 // asserts that that's the case.
1157 assert(is_internal_format(parsed_name),
1158 "external class name format used internally");
1159
1160 #if INCLUDE_JFR
1161 {
1162 InstanceKlass* ik = k();
1163 ON_KLASS_CREATION(ik, parser, THREAD);
1164 k = instanceKlassHandle(ik);
1165 }
1166 #endif
1167
1168 // Add class just loaded
1169 // If a class loader supports parallel classloading handle parallel define requests
1170 // find_or_define_instance_class may return a different InstanceKlass
1171 if (is_parallelCapable(class_loader)) {
1172 k = find_or_define_instance_class(class_name, class_loader, k, THREAD);
1173 } else {
1174 define_instance_class(k, THREAD);
1175 }
1176 }
1177
1178 // Make sure we have an entry in the SystemDictionary on success
1179 debug_only( {
1180 if (!HAS_PENDING_EXCEPTION) {
1181 assert(parsed_name != NULL, "parsed_name is still null?");
1182 Symbol* h_name = k->name();
1183 ClassLoaderData *defining_loader_data = k->class_loader_data();
1184
1185 MutexLocker mu(SystemDictionary_lock, THREAD);
1186
1187 Klass* check = find_class(parsed_name, loader_data);
1188 assert(check == k(), "should be present in the dictionary");
1189
1190 Klass* check2 = find_class(h_name, defining_loader_data);
1191 assert(check == check2, "name inconsistancy in SystemDictionary");
1192 }
1193 } );
1194
1195 return k();
1196 }
1197
1198 #if INCLUDE_CDS
1199 void SystemDictionary::set_shared_dictionary(HashtableBucket<mtClass>* t, int length,
1200 int number_of_entries) {
1201 assert(length == _nof_buckets * sizeof(HashtableBucket<mtClass>),
1202 "bad shared dictionary size.");
1203 _shared_dictionary = new Dictionary(_nof_buckets, t, number_of_entries);
1204 }
1205
1206
1207 // If there is a shared dictionary, then find the entry for the
1208 // given shared system class, if any.
1209
1210 Klass* SystemDictionary::find_shared_class(Symbol* class_name) {
1211 if (shared_dictionary() != NULL) {
1212 unsigned int d_hash = shared_dictionary()->compute_hash(class_name, NULL);
1213 int d_index = shared_dictionary()->hash_to_index(d_hash);
1214
1215 return shared_dictionary()->find_shared_class(d_index, d_hash, class_name);
1216 } else {
1217 return NULL;
1218 }
1219 }
1220
1221
1222 // Load a class from the shared spaces (found through the shared system
1223 // dictionary). Force the superclass and all interfaces to be loaded.
1224 // Update the class definition to include sibling classes and no
1225 // subclasses (yet). [Classes in the shared space are not part of the
1226 // object hierarchy until loaded.]
1227
1228 instanceKlassHandle SystemDictionary::load_shared_class(
1229 Symbol* class_name, Handle class_loader, TRAPS) {
1230 instanceKlassHandle ik (THREAD, find_shared_class(class_name));
1231 // Make sure we only return the boot class for the NULL classloader.
1232 if (ik.not_null() &&
1233 SharedClassUtil::is_shared_boot_class(ik()) && class_loader.is_null()) {
1234 Handle protection_domain;
1235 return load_shared_class(ik, class_loader, protection_domain, THREAD);
1236 }
1237 return instanceKlassHandle();
1238 }
1239
1240 instanceKlassHandle SystemDictionary::load_shared_class(instanceKlassHandle ik,
1241 Handle class_loader,
1242 Handle protection_domain, TRAPS) {
1243 if (ik.not_null()) {
1244 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1245 Symbol* class_name = ik->name();
1246
1247 // Found the class, now load the superclass and interfaces. If they
1248 // are shared, add them to the main system dictionary and reset
1249 // their hierarchy references (supers, subs, and interfaces).
1250
1251 if (ik->super() != NULL) {
1252 Symbol* cn = ik->super()->name();
1253 Klass *s = resolve_super_or_fail(class_name, cn,
1254 class_loader, protection_domain, true, CHECK_(nh));
1255 if (s != ik->super()) {
1256 // The dynamically resolved super class is not the same as the one we used during dump time,
1257 // so we cannot use ik.
1258 return nh;
1259 }
1260 }
1261
1262 Array<Klass*>* interfaces = ik->local_interfaces();
1263 int num_interfaces = interfaces->length();
1264 for (int index = 0; index < num_interfaces; index++) {
1265 Klass* k = interfaces->at(index);
1266
1267 // Note: can not use InstanceKlass::cast here because
1268 // interfaces' InstanceKlass's C++ vtbls haven't been
1269 // reinitialized yet (they will be once the interface classes
1270 // are loaded)
1271 Symbol* name = k->name();
1272 Klass* i = resolve_super_or_fail(class_name, name, class_loader, protection_domain, false, CHECK_(nh));
1273 if (k != i) {
1274 // The dynamically resolved interface class is not the same as the one we used during dump time,
1275 // so we cannot use ik.
1276 return nh;
1277 }
1278 }
1279
1280 // Adjust methods to recover missing data. They need addresses for
1281 // interpreter entry points and their default native method address
1282 // must be reset.
1283
1284 // Updating methods must be done under a lock so multiple
1285 // threads don't update these in parallel
1286 //
1287 // Shared classes are all currently loaded by either the bootstrap or
1288 // internal parallel class loaders, so this will never cause a deadlock
1289 // on a custom class loader lock.
1290
1291 ClassLoaderData* loader_data = ClassLoaderData::class_loader_data(class_loader());
1292 {
1293 Handle lockObject = compute_loader_lock_object(class_loader, THREAD);
1294 check_loader_lock_contention(lockObject, THREAD);
1295 ObjectLocker ol(lockObject, THREAD, true);
1296 ik->restore_unshareable_info(loader_data, protection_domain, CHECK_(nh));
1297 }
1298
1299 if (TraceClassLoading) {
1300 ResourceMark rm;
1301 tty->print("[Loaded %s", ik->external_name());
1302 tty->print(" from shared objects file");
1303 if (class_loader.not_null()) {
1304 tty->print(" by %s", loader_data->loader_name());
1305 }
1306 tty->print_cr("]");
1307 }
1308
1309 if (DumpLoadedClassList != NULL && classlist_file->is_open()) {
1310 // Only dump the classes that can be stored into CDS archive
1311 if (SystemDictionaryShared::is_sharing_possible(loader_data)) {
1312 ResourceMark rm(THREAD);
1313 classlist_file->print_cr("%s", ik->name()->as_C_string());
1314 classlist_file->flush();
1315 }
1316 }
1317
1318 // notify a class loaded from shared object
1319 ClassLoadingService::notify_class_loaded(InstanceKlass::cast(ik()),
1320 true /* shared class */);
1321 }
1322 return ik;
1323 }
1324 #endif // INCLUDE_CDS
1325
1326 instanceKlassHandle SystemDictionary::load_instance_class(Symbol* class_name, Handle class_loader, TRAPS) {
1327 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1328 if (class_loader.is_null()) {
1329
1330 // Search the shared system dictionary for classes preloaded into the
1331 // shared spaces.
1332 instanceKlassHandle k;
1333 {
1334 #if INCLUDE_CDS
1335 PerfTraceTime vmtimer(ClassLoader::perf_shared_classload_time());
1336 k = load_shared_class(class_name, class_loader, THREAD);
1337 #endif
1338 }
1339
1340 if (k.is_null()) {
1341 // Use VM class loader
1342 PerfTraceTime vmtimer(ClassLoader::perf_sys_classload_time());
1343 k = ClassLoader::load_classfile(class_name, CHECK_(nh));
1344 }
1345
1346 // find_or_define_instance_class may return a different InstanceKlass
1347 if (!k.is_null()) {
1348 k = find_or_define_instance_class(class_name, class_loader, k, CHECK_(nh));
1349 }
1350 #if INCLUDE_JFR
1351 else {
1352 assert(jfr_event_handler_proxy != NULL, "invariant");
1353 if (class_name == jfr_event_handler_proxy) {
1354 // EventHandlerProxy class is generated dynamically in
1355 // EventHandlerProxyCreator::makeEventHandlerProxyClass
1356 // method, so we generate a Java call from here.
1357 //
1358 // EventHandlerProxy class will finally be defined in
1359 // SystemDictionary::resolve_from_stream method, down
1360 // the call stack. Bootstrap classloader is parallel-capable,
1361 // so no concurrency issues are expected.
1362 CLEAR_PENDING_EXCEPTION;
1363 k = JfrUpcalls::load_event_handler_proxy_class(THREAD);
1364 assert(!k.is_null(), "invariant");
1365 }
1366 }
1367 #endif // INCLUDE_JFR
1368
1369 return k;
1370 } else {
1371 // Use user specified class loader to load class. Call loadClass operation on class_loader.
1372 ResourceMark rm(THREAD);
1373
1374 assert(THREAD->is_Java_thread(), "must be a JavaThread");
1375 JavaThread* jt = (JavaThread*) THREAD;
1376
1377 PerfClassTraceTime vmtimer(ClassLoader::perf_app_classload_time(),
1378 ClassLoader::perf_app_classload_selftime(),
1379 ClassLoader::perf_app_classload_count(),
1380 jt->get_thread_stat()->perf_recursion_counts_addr(),
1381 jt->get_thread_stat()->perf_timers_addr(),
1382 PerfClassTraceTime::CLASS_LOAD);
1383
1384 Handle s = java_lang_String::create_from_symbol(class_name, CHECK_(nh));
1385 // Translate to external class name format, i.e., convert '/' chars to '.'
1386 Handle string = java_lang_String::externalize_classname(s, CHECK_(nh));
1387
1388 JavaValue result(T_OBJECT);
1389
1390 KlassHandle spec_klass (THREAD, SystemDictionary::ClassLoader_klass());
1391
1392 // Call public unsynchronized loadClass(String) directly for all class loaders
1393 // for parallelCapable class loaders. JDK >=7, loadClass(String, boolean) will
1394 // acquire a class-name based lock rather than the class loader object lock.
1395 // JDK < 7 already acquire the class loader lock in loadClass(String, boolean),
1396 // so the call to loadClassInternal() was not required.
1397 //
1398 // UnsyncloadClass flag means both call loadClass(String) and do
1399 // not acquire the class loader lock even for class loaders that are
1400 // not parallelCapable. This was a risky transitional
1401 // flag for diagnostic purposes only. It is risky to call
1402 // custom class loaders without synchronization.
1403 // WARNING If a custom class loader does NOT synchronizer findClass, or callers of
1404 // findClass, the UnsyncloadClass flag risks unexpected timing bugs in the field.
1405 // Do NOT assume this will be supported in future releases.
1406 //
1407 // Added MustCallLoadClassInternal in case we discover in the field
1408 // a customer that counts on this call
1409 if (MustCallLoadClassInternal && has_loadClassInternal()) {
1410 JavaCalls::call_special(&result,
1411 class_loader,
1412 spec_klass,
1413 vmSymbols::loadClassInternal_name(),
1414 vmSymbols::string_class_signature(),
1415 string,
1416 CHECK_(nh));
1417 } else {
1418 JavaCalls::call_virtual(&result,
1419 class_loader,
1420 spec_klass,
1421 vmSymbols::loadClass_name(),
1422 vmSymbols::string_class_signature(),
1423 string,
1424 CHECK_(nh));
1425 }
1426
1427 assert(result.get_type() == T_OBJECT, "just checking");
1428 oop obj = (oop) result.get_jobject();
1429
1430 // Primitive classes return null since forName() can not be
1431 // used to obtain any of the Class objects representing primitives or void
1432 if ((obj != NULL) && !(java_lang_Class::is_primitive(obj))) {
1433 instanceKlassHandle k =
1434 instanceKlassHandle(THREAD, java_lang_Class::as_Klass(obj));
1435 // For user defined Java class loaders, check that the name returned is
1436 // the same as that requested. This check is done for the bootstrap
1437 // loader when parsing the class file.
1438 if (class_name == k->name()) {
1439 return k;
1440 }
1441 }
1442 // Class is not found or has the wrong name, return NULL
1443 return nh;
1444 }
1445 }
1446
1447 #if INCLUDE_JFR
1448 static void post_class_define_event(InstanceKlass* k, const ClassLoaderData* def_cld) {
1449 EventClassDefine event;
1450 if (event.should_commit()) {
1451 event.set_definedClass(k);
1452 event.set_definingClassLoader(def_cld);
1453 event.commit();
1454 }
1455 }
1456 #endif
1457
1458 void SystemDictionary::define_instance_class(instanceKlassHandle k, TRAPS) {
1459
1460 ClassLoaderData* loader_data = k->class_loader_data();
1461 Handle class_loader_h(THREAD, loader_data->class_loader());
1462
1463 for (uintx it = 0; it < GCExpandToAllocateDelayMillis; it++){}
1464
1465 // for bootstrap and other parallel classloaders don't acquire lock,
1466 // use placeholder token
1467 // If a parallelCapable class loader calls define_instance_class instead of
1468 // find_or_define_instance_class to get here, we have a timing
1469 // hole with systemDictionary updates and check_constraints
1470 if (!class_loader_h.is_null() && !is_parallelCapable(class_loader_h)) {
1471 assert(ObjectSynchronizer::current_thread_holds_lock((JavaThread*)THREAD,
1472 compute_loader_lock_object(class_loader_h, THREAD)),
1473 "define called without lock");
1474 }
1475
1476 // Check class-loading constraints. Throw exception if violation is detected.
1477 // Grabs and releases SystemDictionary_lock
1478 // The check_constraints/find_class call and update_dictionary sequence
1479 // must be "atomic" for a specific class/classloader pair so we never
1480 // define two different instanceKlasses for that class/classloader pair.
1481 // Existing classloaders will call define_instance_class with the
1482 // classloader lock held
1483 // Parallel classloaders will call find_or_define_instance_class
1484 // which will require a token to perform the define class
1485 Symbol* name_h = k->name();
1486 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1487 int d_index = dictionary()->hash_to_index(d_hash);
1488 check_constraints(d_index, d_hash, k, class_loader_h, true, CHECK);
1489
1490 // Register class just loaded with class loader (placed in Vector)
1491 // Note we do this before updating the dictionary, as this can
1492 // fail with an OutOfMemoryError (if it does, we will *not* put this
1493 // class in the dictionary and will not update the class hierarchy).
1494 // JVMTI FollowReferences needs to find the classes this way.
1495 if (k->class_loader() != NULL) {
1496 methodHandle m(THREAD, Universe::loader_addClass_method());
1497 JavaValue result(T_VOID);
1498 JavaCallArguments args(class_loader_h);
1499 args.push_oop(Handle(THREAD, k->java_mirror()));
1500 JavaCalls::call(&result, m, &args, CHECK);
1501 }
1502
1503 // Add the new class. We need recompile lock during update of CHA.
1504 {
1505 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1506 int p_index = placeholders()->hash_to_index(p_hash);
1507
1508 MutexLocker mu_r(Compile_lock, THREAD);
1509
1510 // Add to class hierarchy, initialize vtables, and do possible
1511 // deoptimizations.
1512 add_to_hierarchy(k, CHECK); // No exception, but can block
1513
1514 // Add to systemDictionary - so other classes can see it.
1515 // Grabs and releases SystemDictionary_lock
1516 update_dictionary(d_index, d_hash, p_index, p_hash,
1517 k, class_loader_h, THREAD);
1518 }
1519 k->eager_initialize(THREAD);
1520
1521 // notify jvmti
1522 if (JvmtiExport::should_post_class_load()) {
1523 assert(THREAD->is_Java_thread(), "thread->is_Java_thread()");
1524 JvmtiExport::post_class_load((JavaThread *) THREAD, k());
1525
1526 }
1527
1528 #if INCLUDE_JFR
1529 post_class_define_event(k(), loader_data);
1530 #endif
1531 }
1532
1533 // Support parallel classloading
1534 // All parallel class loaders, including bootstrap classloader
1535 // lock a placeholder entry for this class/class_loader pair
1536 // to allow parallel defines of different classes for this class loader
1537 // With AllowParallelDefine flag==true, in case they do not synchronize around
1538 // FindLoadedClass/DefineClass, calls, we check for parallel
1539 // loading for them, wait if a defineClass is in progress
1540 // and return the initial requestor's results
1541 // This flag does not apply to the bootstrap classloader.
1542 // With AllowParallelDefine flag==false, call through to define_instance_class
1543 // which will throw LinkageError: duplicate class definition.
1544 // False is the requested default.
1545 // For better performance, the class loaders should synchronize
1546 // findClass(), i.e. FindLoadedClass/DefineClassIfAbsent or they
1547 // potentially waste time reading and parsing the bytestream.
1548 // Note: VM callers should ensure consistency of k/class_name,class_loader
1549 instanceKlassHandle SystemDictionary::find_or_define_instance_class(Symbol* class_name, Handle class_loader, instanceKlassHandle k, TRAPS) {
1550
1551 instanceKlassHandle nh = instanceKlassHandle(); // null Handle
1552 Symbol* name_h = k->name(); // passed in class_name may be null
1553 ClassLoaderData* loader_data = class_loader_data(class_loader);
1554
1555 unsigned int d_hash = dictionary()->compute_hash(name_h, loader_data);
1556 int d_index = dictionary()->hash_to_index(d_hash);
1557
1558 // Hold SD lock around find_class and placeholder creation for DEFINE_CLASS
1559 unsigned int p_hash = placeholders()->compute_hash(name_h, loader_data);
1560 int p_index = placeholders()->hash_to_index(p_hash);
1561 PlaceholderEntry* probe;
1562
1563 {
1564 MutexLocker mu(SystemDictionary_lock, THREAD);
1565 // First check if class already defined
1566 if (UnsyncloadClass || (is_parallelDefine(class_loader))) {
1567 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1568 if (check != NULL) {
1569 return(instanceKlassHandle(THREAD, check));
1570 }
1571 }
1572
1573 // Acquire define token for this class/classloader
1574 probe = placeholders()->find_and_add(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, NULL, THREAD);
1575 // Wait if another thread defining in parallel
1576 // All threads wait - even those that will throw duplicate class: otherwise
1577 // caller is surprised by LinkageError: duplicate, but findLoadedClass fails
1578 // if other thread has not finished updating dictionary
1579 while (probe->definer() != NULL) {
1580 SystemDictionary_lock->wait();
1581 }
1582 // Only special cases allow parallel defines and can use other thread's results
1583 // Other cases fall through, and may run into duplicate defines
1584 // caught by finding an entry in the SystemDictionary
1585 if ((UnsyncloadClass || is_parallelDefine(class_loader)) && (probe->instance_klass() != NULL)) {
1586 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1587 SystemDictionary_lock->notify_all();
1588 #ifdef ASSERT
1589 Klass* check = find_class(d_index, d_hash, name_h, loader_data);
1590 assert(check != NULL, "definer missed recording success");
1591 #endif
1592 return(instanceKlassHandle(THREAD, probe->instance_klass()));
1593 } else {
1594 // This thread will define the class (even if earlier thread tried and had an error)
1595 probe->set_definer(THREAD);
1596 }
1597 }
1598
1599 define_instance_class(k, THREAD);
1600
1601 Handle linkage_exception = Handle(); // null handle
1602
1603 // definer must notify any waiting threads
1604 {
1605 MutexLocker mu(SystemDictionary_lock, THREAD);
1606 PlaceholderEntry* probe = placeholders()->get_entry(p_index, p_hash, name_h, loader_data);
1607 assert(probe != NULL, "DEFINE_CLASS placeholder lost?");
1608 if (probe != NULL) {
1609 if (HAS_PENDING_EXCEPTION) {
1610 linkage_exception = Handle(THREAD,PENDING_EXCEPTION);
1611 CLEAR_PENDING_EXCEPTION;
1612 } else {
1613 probe->set_instance_klass(k());
1614 }
1615 probe->set_definer(NULL);
1616 placeholders()->find_and_remove(p_index, p_hash, name_h, loader_data, PlaceholderTable::DEFINE_CLASS, THREAD);
1617 SystemDictionary_lock->notify_all();
1618 }
1619 }
1620
1621 // Can't throw exception while holding lock due to rank ordering
1622 if (linkage_exception() != NULL) {
1623 THROW_OOP_(linkage_exception(), nh); // throws exception and returns
1624 }
1625
1626 return k;
1627 }
1628 Handle SystemDictionary::compute_loader_lock_object(Handle class_loader, TRAPS) {
1629 // If class_loader is NULL we synchronize on _system_loader_lock_obj
1630 if (class_loader.is_null()) {
1631 return Handle(THREAD, _system_loader_lock_obj);
1632 } else {
1633 return class_loader;
1634 }
1635 }
1636
1637 // This method is added to check how often we have to wait to grab loader
1638 // lock. The results are being recorded in the performance counters defined in
1639 // ClassLoader::_sync_systemLoaderLockContentionRate and
1640 // ClassLoader::_sync_nonSystemLoaderLockConteionRate.
1641 void SystemDictionary::check_loader_lock_contention(Handle loader_lock, TRAPS) {
1642 if (!UsePerfData) {
1643 return;
1644 }
1645
1646 assert(!loader_lock.is_null(), "NULL lock object");
1647
1648 if (ObjectSynchronizer::query_lock_ownership((JavaThread*)THREAD, loader_lock)
1649 == ObjectSynchronizer::owner_other) {
1650 // contention will likely happen, so increment the corresponding
1651 // contention counter.
1652 if (loader_lock() == _system_loader_lock_obj) {
1653 ClassLoader::sync_systemLoaderLockContentionRate()->inc();
1654 } else {
1655 ClassLoader::sync_nonSystemLoaderLockContentionRate()->inc();
1656 }
1657 }
1658 }
1659
1660 // ----------------------------------------------------------------------------
1661 // Lookup
1662
1663 Klass* SystemDictionary::find_class(int index, unsigned int hash,
1664 Symbol* class_name,
1665 ClassLoaderData* loader_data) {
1666 assert_locked_or_safepoint(SystemDictionary_lock);
1667 assert (index == dictionary()->index_for(class_name, loader_data),
1668 "incorrect index?");
1669
1670 Klass* k = dictionary()->find_class(index, hash, class_name, loader_data);
1671 return k;
1672 }
1673
1674
1675 // Basic find on classes in the midst of being loaded
1676 Symbol* SystemDictionary::find_placeholder(Symbol* class_name,
1677 ClassLoaderData* loader_data) {
1678 assert_locked_or_safepoint(SystemDictionary_lock);
1679 unsigned int p_hash = placeholders()->compute_hash(class_name, loader_data);
1680 int p_index = placeholders()->hash_to_index(p_hash);
1681 return placeholders()->find_entry(p_index, p_hash, class_name, loader_data);
1682 }
1683
1684
1685 // Used for assertions and verification only
1686 Klass* SystemDictionary::find_class(Symbol* class_name, ClassLoaderData* loader_data) {
1687 #ifndef ASSERT
1688 guarantee(VerifyBeforeGC ||
1689 VerifyDuringGC ||
1690 VerifyBeforeExit ||
1691 VerifyDuringStartup ||
1692 VerifyAfterGC, "too expensive");
1693 #endif
1694 assert_locked_or_safepoint(SystemDictionary_lock);
1695
1696 // First look in the loaded class array
1697 unsigned int d_hash = dictionary()->compute_hash(class_name, loader_data);
1698 int d_index = dictionary()->hash_to_index(d_hash);
1699 return find_class(d_index, d_hash, class_name, loader_data);
1700 }
1701
1702
1703 // Get the next class in the diictionary.
1704 Klass* SystemDictionary::try_get_next_class() {
1705 return dictionary()->try_get_next_class();
1706 }
1707
1708
1709 // ----------------------------------------------------------------------------
1710 // Update hierachy. This is done before the new klass has been added to the SystemDictionary. The Recompile_lock
1711 // is held, to ensure that the compiler is not using the class hierachy, and that deoptimization will kick in
1712 // before a new class is used.
1713
1714 void SystemDictionary::add_to_hierarchy(instanceKlassHandle k, TRAPS) {
1715 assert(k.not_null(), "just checking");
1716 assert_locked_or_safepoint(Compile_lock);
1717
1718 // Link into hierachy. Make sure the vtables are initialized before linking into
1719 k->append_to_sibling_list(); // add to superklass/sibling list
1720 k->process_interfaces(THREAD); // handle all "implements" declarations
1721 k->set_init_state(InstanceKlass::loaded);
1722 // Now flush all code that depended on old class hierarchy.
1723 // Note: must be done *after* linking k into the hierarchy (was bug 12/9/97)
1724 // Also, first reinitialize vtable because it may have gotten out of synch
1725 // while the new class wasn't connected to the class hierarchy.
1726 Universe::flush_dependents_on(k);
1727 }
1728
1729 // ----------------------------------------------------------------------------
1730 // GC support
1731
1732 // Following roots during mark-sweep is separated in two phases.
1733 //
1734 // The first phase follows preloaded classes and all other system
1735 // classes, since these will never get unloaded anyway.
1736 //
1737 // The second phase removes (unloads) unreachable classes from the
1738 // system dictionary and follows the remaining classes' contents.
1739
1740 void SystemDictionary::always_strong_oops_do(OopClosure* blk) {
1741 roots_oops_do(blk, NULL);
1742 }
1743
1744 void SystemDictionary::always_strong_classes_do(KlassClosure* closure) {
1745 // Follow all system classes and temporary placeholders in dictionary
1746 dictionary()->always_strong_classes_do(closure);
1747
1748 // Placeholders. These represent classes we're actively loading.
1749 placeholders()->classes_do(closure);
1750 }
1751
1752 // Calculate a "good" systemdictionary size based
1753 // on predicted or current loaded classes count
1754 int SystemDictionary::calculate_systemdictionary_size(int classcount) {
1755 int newsize = _old_default_sdsize;
1756 if ((classcount > 0) && !DumpSharedSpaces) {
1757 int desiredsize = classcount/_average_depth_goal;
1758 for (newsize = _primelist[_sdgeneration]; _sdgeneration < _prime_array_size -1;
1759 newsize = _primelist[++_sdgeneration]) {
1760 if (desiredsize <= newsize) {
1761 break;
1762 }
1763 }
1764 }
1765 return newsize;
1766 }
1767
1768 #ifdef ASSERT
1769 class VerifySDReachableAndLiveClosure : public OopClosure {
1770 private:
1771 BoolObjectClosure* _is_alive;
1772
1773 template <class T> void do_oop_work(T* p) {
1774 oop obj = oopDesc::load_decode_heap_oop(p);
1775 guarantee(_is_alive->do_object_b(obj), "Oop in system dictionary must be live");
1776 }
1777
1778 public:
1779 VerifySDReachableAndLiveClosure(BoolObjectClosure* is_alive) : OopClosure(), _is_alive(is_alive) { }
1780
1781 virtual void do_oop(oop* p) { do_oop_work(p); }
1782 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
1783 };
1784 #endif
1785
1786 // Assumes classes in the SystemDictionary are only unloaded at a safepoint
1787 // Note: anonymous classes are not in the SD.
1788 bool SystemDictionary::do_unloading(BoolObjectClosure* is_alive, bool clean_alive) {
1789 // First, mark for unload all ClassLoaderData referencing a dead class loader.
1790 bool unloading_occurred = ClassLoaderDataGraph::do_unloading(is_alive, clean_alive);
1791 if (unloading_occurred) {
1792 JFR_ONLY(Jfr::on_unloading_classes();)
1793 dictionary()->do_unloading();
1794 constraints()->purge_loader_constraints();
1795 resolution_errors()->purge_resolution_errors();
1796 }
1797 // Oops referenced by the system dictionary may get unreachable independently
1798 // of the class loader (eg. cached protection domain oops). So we need to
1799 // explicitly unlink them here instead of in Dictionary::do_unloading.
1800 dictionary()->unlink(is_alive);
1801 #ifdef ASSERT
1802 VerifySDReachableAndLiveClosure cl(is_alive);
1803 dictionary()->oops_do(&cl);
1804 #endif
1805 return unloading_occurred;
1806 }
1807
1808 void SystemDictionary::roots_oops_do(OopClosure* strong, OopClosure* weak) {
1809 strong->do_oop(&_java_system_loader);
1810 strong->do_oop(&_system_loader_lock_obj);
1811 CDS_ONLY(SystemDictionaryShared::roots_oops_do(strong);)
1812
1813 // Adjust dictionary
1814 dictionary()->roots_oops_do(strong, weak);
1815
1816 // Visit extra methods
1817 invoke_method_table()->oops_do(strong);
1818 }
1819
1820 void SystemDictionary::oops_do(OopClosure* f) {
1821 f->do_oop(&_java_system_loader);
1822 f->do_oop(&_system_loader_lock_obj);
1823 CDS_ONLY(SystemDictionaryShared::oops_do(f);)
1824
1825 // Adjust dictionary
1826 dictionary()->oops_do(f);
1827
1828 // Visit extra methods
1829 invoke_method_table()->oops_do(f);
1830 }
1831
1832 // Extended Class redefinition support.
1833 // If one of these classes is replaced, we need to replace it in these places.
1834 // KlassClosure::do_klass should take the address of a class but we can
1835 // change that later.
1836 void SystemDictionary::preloaded_classes_do(KlassClosure* f) {
1837 for (int k = (int)FIRST_WKID; k < (int)WKID_LIMIT; k++) {
1838 f->do_klass(_well_known_klasses[k]);
1839 }
1840
1841 {
1842 for (int i = 0; i < T_VOID+1; i++) {
1843 if (_box_klasses[i] != NULL) {
1844 assert(i >= T_BOOLEAN, "checking");
1845 f->do_klass(_box_klasses[i]);
1846 }
1847 }
1848 }
1849
1850 FilteredFieldsMap::classes_do(f);
1851 }
1852
1853 void SystemDictionary::lazily_loaded_classes_do(KlassClosure* f) {
1854 f->do_klass(_abstract_ownable_synchronizer_klass);
1855 }
1856
1857 // Just the classes from defining class loaders
1858 // Don't iterate over placeholders
1859 void SystemDictionary::classes_do(void f(Klass*)) {
1860 dictionary()->classes_do(f);
1861 }
1862
1863 // Added for initialize_itable_for_klass
1864 // Just the classes from defining class loaders
1865 // Don't iterate over placeholders
1866 void SystemDictionary::classes_do(void f(Klass*, TRAPS), TRAPS) {
1867 dictionary()->classes_do(f, CHECK);
1868 }
1869
1870 // All classes, and their class loaders
1871 // Don't iterate over placeholders
1872 void SystemDictionary::classes_do(void f(Klass*, ClassLoaderData*)) {
1873 dictionary()->classes_do(f);
1874 }
1875
1876 void SystemDictionary::placeholders_do(void f(Symbol*)) {
1877 placeholders()->entries_do(f);
1878 }
1879
1880 void SystemDictionary::methods_do(void f(Method*)) {
1881 dictionary()->methods_do(f);
1882 invoke_method_table()->methods_do(f);
1883 }
1884
1885 void SystemDictionary::remove_classes_in_error_state() {
1886 dictionary()->remove_classes_in_error_state();
1887 }
1888
1889 // ----------------------------------------------------------------------------
1890 // Lazily load klasses
1891
1892 void SystemDictionary::load_abstract_ownable_synchronizer_klass(TRAPS) {
1893 assert(JDK_Version::is_gte_jdk16x_version(), "Must be JDK 1.6 or later");
1894
1895 // if multiple threads calling this function, only one thread will load
1896 // the class. The other threads will find the loaded version once the
1897 // class is loaded.
1898 Klass* aos = _abstract_ownable_synchronizer_klass;
1899 if (aos == NULL) {
1900 Klass* k = resolve_or_fail(vmSymbols::java_util_concurrent_locks_AbstractOwnableSynchronizer(), true, CHECK);
1901 // Force a fence to prevent any read before the write completes
1902 OrderAccess::fence();
1903 _abstract_ownable_synchronizer_klass = k;
1904 }
1905 }
1906
1907 // ----------------------------------------------------------------------------
1908 // Initialization
1909
1910 void SystemDictionary::initialize(TRAPS) {
1911 // Allocate arrays
1912 assert(dictionary() == NULL,
1913 "SystemDictionary should only be initialized once");
1914 _sdgeneration = 0;
1915 _dictionary = new Dictionary(calculate_systemdictionary_size(PredictedLoadedClassCount));
1916 _placeholders = new PlaceholderTable(_nof_buckets);
1917 _number_of_modifications = 0;
1918 _loader_constraints = new LoaderConstraintTable(_loader_constraint_size);
1919 _resolution_errors = new ResolutionErrorTable(_resolution_error_size);
1920 _invoke_method_table = new SymbolPropertyTable(_invoke_method_size);
1921
1922 // Allocate private object used as system class loader lock
1923 _system_loader_lock_obj = oopFactory::new_intArray(0, CHECK);
1924 // Initialize basic classes
1925 initialize_preloaded_classes(CHECK);
1926 #if INCLUDE_JFR
1927 jfr_event_handler_proxy = SymbolTable::new_permanent_symbol("jdk/jfr/proxy/internal/EventHandlerProxy", CHECK);
1928 #endif // INCLUDE_JFR
1929 }
1930
1931 // Compact table of directions on the initialization of klasses:
1932 static const short wk_init_info[] = {
1933 #define WK_KLASS_INIT_INFO(name, symbol, option) \
1934 ( ((int)vmSymbols::VM_SYMBOL_ENUM_NAME(symbol) \
1935 << SystemDictionary::CEIL_LG_OPTION_LIMIT) \
1936 | (int)SystemDictionary::option ),
1937 WK_KLASSES_DO(WK_KLASS_INIT_INFO)
1938 #undef WK_KLASS_INIT_INFO
1939 0
1940 };
1941
1942 bool SystemDictionary::initialize_wk_klass(WKID id, int init_opt, TRAPS) {
1943 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1944 int info = wk_init_info[id - FIRST_WKID];
1945 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1946 Symbol* symbol = vmSymbols::symbol_at((vmSymbols::SID)sid);
1947 Klass** klassp = &_well_known_klasses[id];
1948 bool must_load = (init_opt < SystemDictionary::Opt);
1949 if ((*klassp) == NULL) {
1950 if (must_load) {
1951 (*klassp) = resolve_or_fail(symbol, true, CHECK_0); // load required class
1952 } else {
1953 (*klassp) = resolve_or_null(symbol, CHECK_0); // load optional klass
1954 }
1955 }
1956 return ((*klassp) != NULL);
1957 }
1958
1959 void SystemDictionary::initialize_wk_klasses_until(WKID limit_id, WKID &start_id, TRAPS) {
1960 assert((int)start_id <= (int)limit_id, "IDs are out of order!");
1961 for (int id = (int)start_id; id < (int)limit_id; id++) {
1962 assert(id >= (int)FIRST_WKID && id < (int)WKID_LIMIT, "oob");
1963 int info = wk_init_info[id - FIRST_WKID];
1964 int sid = (info >> CEIL_LG_OPTION_LIMIT);
1965 int opt = (info & right_n_bits(CEIL_LG_OPTION_LIMIT));
1966
1967 initialize_wk_klass((WKID)id, opt, CHECK);
1968 }
1969
1970 // move the starting value forward to the limit:
1971 start_id = limit_id;
1972 }
1973
1974 void SystemDictionary::initialize_preloaded_classes(TRAPS) {
1975 assert(WK_KLASS(Object_klass) == NULL, "preloaded classes should only be initialized once");
1976 // Preload commonly used klasses
1977 WKID scan = FIRST_WKID;
1978 // first do Object, then String, Class
1979 if (UseSharedSpaces) {
1980 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Object_klass), scan, CHECK);
1981 // Initialize the constant pool for the Object_class
1982 InstanceKlass* ik = InstanceKlass::cast(Object_klass());
1983 ik->constants()->restore_unshareable_info(CHECK);
1984 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1985 } else {
1986 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Class_klass), scan, CHECK);
1987 }
1988
1989 // Calculate offsets for String and Class classes since they are loaded and
1990 // can be used after this point.
1991 java_lang_String::compute_offsets();
1992 java_lang_Class::compute_offsets();
1993
1994 // Fixup mirrors for classes loaded before java.lang.Class.
1995 // These calls iterate over the objects currently in the perm gen
1996 // so calling them at this point is matters (not before when there
1997 // are fewer objects and not later after there are more objects
1998 // in the perm gen.
1999 Universe::initialize_basic_type_mirrors(CHECK);
2000 Universe::fixup_mirrors(CHECK);
2001
2002 // do a bunch more:
2003 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Reference_klass), scan, CHECK);
2004
2005 // Preload ref klasses and set reference types
2006 InstanceKlass::cast(WK_KLASS(Reference_klass))->set_reference_type(REF_OTHER);
2007 InstanceRefKlass::update_nonstatic_oop_maps(WK_KLASS(Reference_klass));
2008
2009 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(Cleaner_klass), scan, CHECK);
2010 InstanceKlass::cast(WK_KLASS(SoftReference_klass))->set_reference_type(REF_SOFT);
2011 InstanceKlass::cast(WK_KLASS(WeakReference_klass))->set_reference_type(REF_WEAK);
2012 InstanceKlass::cast(WK_KLASS(FinalReference_klass))->set_reference_type(REF_FINAL);
2013 InstanceKlass::cast(WK_KLASS(PhantomReference_klass))->set_reference_type(REF_PHANTOM);
2014 InstanceKlass::cast(WK_KLASS(Cleaner_klass))->set_reference_type(REF_CLEANER);
2015
2016 initialize_wk_klasses_through(WK_KLASS_ENUM_NAME(ReferenceQueue_klass), scan, CHECK);
2017
2018 // JSR 292 classes
2019 WKID jsr292_group_start = WK_KLASS_ENUM_NAME(MethodHandle_klass);
2020 WKID jsr292_group_end = WK_KLASS_ENUM_NAME(VolatileCallSite_klass);
2021 initialize_wk_klasses_until(jsr292_group_start, scan, CHECK);
2022 if (EnableInvokeDynamic) {
2023 initialize_wk_klasses_through(jsr292_group_end, scan, CHECK);
2024 } else {
2025 // Skip the JSR 292 classes, if not enabled.
2026 scan = WKID(jsr292_group_end + 1);
2027 }
2028
2029 initialize_wk_klasses_until(WKID_LIMIT, scan, CHECK);
2030
2031 _box_klasses[T_BOOLEAN] = WK_KLASS(Boolean_klass);
2032 _box_klasses[T_CHAR] = WK_KLASS(Character_klass);
2033 _box_klasses[T_FLOAT] = WK_KLASS(Float_klass);
2034 _box_klasses[T_DOUBLE] = WK_KLASS(Double_klass);
2035 _box_klasses[T_BYTE] = WK_KLASS(Byte_klass);
2036 _box_klasses[T_SHORT] = WK_KLASS(Short_klass);
2037 _box_klasses[T_INT] = WK_KLASS(Integer_klass);
2038 _box_klasses[T_LONG] = WK_KLASS(Long_klass);
2039 //_box_klasses[T_OBJECT] = WK_KLASS(object_klass);
2040 //_box_klasses[T_ARRAY] = WK_KLASS(object_klass);
2041
2042 { // Compute whether we should use loadClass or loadClassInternal when loading classes.
2043 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::loadClassInternal_name(), vmSymbols::string_class_signature());
2044 _has_loadClassInternal = (method != NULL);
2045 }
2046 { // Compute whether we should use checkPackageAccess or NOT
2047 Method* method = InstanceKlass::cast(ClassLoader_klass())->find_method(vmSymbols::checkPackageAccess_name(), vmSymbols::class_protectiondomain_signature());
2048 _has_checkPackageAccess = (method != NULL);
2049 }
2050 }
2051
2052 // Tells if a given klass is a box (wrapper class, such as java.lang.Integer).
2053 // If so, returns the basic type it holds. If not, returns T_OBJECT.
2054 BasicType SystemDictionary::box_klass_type(Klass* k) {
2055 assert(k != NULL, "");
2056 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
2057 if (_box_klasses[i] == k)
2058 return (BasicType)i;
2059 }
2060 return T_OBJECT;
2061 }
2062
2063 // Constraints on class loaders. The details of the algorithm can be
2064 // found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
2065 // Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
2066 // that the system dictionary needs to maintain a set of contraints that
2067 // must be satisfied by all classes in the dictionary.
2068 // if defining is true, then LinkageError if already in systemDictionary
2069 // if initiating loader, then ok if InstanceKlass matches existing entry
2070
2071 void SystemDictionary::check_constraints(int d_index, unsigned int d_hash,
2072 instanceKlassHandle k,
2073 Handle class_loader, bool defining,
2074 TRAPS) {
2075 const char *linkage_error = NULL;
2076 {
2077 Symbol* name = k->name();
2078 ClassLoaderData *loader_data = class_loader_data(class_loader);
2079
2080 MutexLocker mu(SystemDictionary_lock, THREAD);
2081
2082 Klass* check = find_class(d_index, d_hash, name, loader_data);
2083 if (check != (Klass*)NULL) {
2084 // if different InstanceKlass - duplicate class definition,
2085 // else - ok, class loaded by a different thread in parallel,
2086 // we should only have found it if it was done loading and ok to use
2087 // system dictionary only holds instance classes, placeholders
2088 // also holds array classes
2089
2090 assert(check->oop_is_instance(), "noninstance in systemdictionary");
2091 if ((defining == true) || (k() != check)) {
2092 linkage_error = "loader (instance of %s): attempted duplicate class "
2093 "definition for name: \"%s\"";
2094 } else {
2095 return;
2096 }
2097 }
2098
2099 #ifdef ASSERT
2100 Symbol* ph_check = find_placeholder(name, loader_data);
2101 assert(ph_check == NULL || ph_check == name, "invalid symbol");
2102 #endif
2103
2104 if (linkage_error == NULL) {
2105 if (constraints()->check_or_update(k, class_loader, name) == false) {
2106 linkage_error = "loader constraint violation: loader (instance of %s)"
2107 " previously initiated loading for a different type with name \"%s\"";
2108 }
2109 }
2110 }
2111
2112 // Throw error now if needed (cannot throw while holding
2113 // SystemDictionary_lock because of rank ordering)
2114
2115 if (linkage_error) {
2116 ResourceMark rm(THREAD);
2117 const char* class_loader_name = loader_name(class_loader());
2118 char* type_name = k->name()->as_C_string();
2119 size_t buflen = strlen(linkage_error) + strlen(class_loader_name) +
2120 strlen(type_name);
2121 char* buf = NEW_RESOURCE_ARRAY_IN_THREAD(THREAD, char, buflen);
2122 jio_snprintf(buf, buflen, linkage_error, class_loader_name, type_name);
2123 THROW_MSG(vmSymbols::java_lang_LinkageError(), buf);
2124 }
2125 }
2126
2127
2128 // Update system dictionary - done after check_constraint and add_to_hierachy
2129 // have been called.
2130 void SystemDictionary::update_dictionary(int d_index, unsigned int d_hash,
2131 int p_index, unsigned int p_hash,
2132 instanceKlassHandle k,
2133 Handle class_loader,
2134 TRAPS) {
2135 // Compile_lock prevents systemDictionary updates during compilations
2136 assert_locked_or_safepoint(Compile_lock);
2137 Symbol* name = k->name();
2138 ClassLoaderData *loader_data = class_loader_data(class_loader);
2139
2140 {
2141 MutexLocker mu1(SystemDictionary_lock, THREAD);
2142
2143 // See whether biased locking is enabled and if so set it for this
2144 // klass.
2145 // Note that this must be done past the last potential blocking
2146 // point / safepoint. We enable biased locking lazily using a
2147 // VM_Operation to iterate the SystemDictionary and installing the
2148 // biasable mark word into each InstanceKlass's prototype header.
2149 // To avoid race conditions where we accidentally miss enabling the
2150 // optimization for one class in the process of being added to the
2151 // dictionary, we must not safepoint after the test of
2152 // BiasedLocking::enabled().
2153 if (UseBiasedLocking && BiasedLocking::enabled()) {
2154 // Set biased locking bit for all loaded classes; it will be
2155 // cleared if revocation occurs too often for this type
2156 // NOTE that we must only do this when the class is initally
2157 // defined, not each time it is referenced from a new class loader
2158 if (k->class_loader() == class_loader()) {
2159 k->set_prototype_header(markOopDesc::biased_locking_prototype());
2160 }
2161 }
2162
2163 // Make a new system dictionary entry.
2164 Klass* sd_check = find_class(d_index, d_hash, name, loader_data);
2165 if (sd_check == NULL) {
2166 dictionary()->add_klass(name, loader_data, k);
2167 notice_modification();
2168 }
2169 #ifdef ASSERT
2170 sd_check = find_class(d_index, d_hash, name, loader_data);
2171 assert (sd_check != NULL, "should have entry in system dictionary");
2172 // Note: there may be a placeholder entry: for circularity testing
2173 // or for parallel defines
2174 #endif
2175 SystemDictionary_lock->notify_all();
2176 }
2177 }
2178
2179
2180 // Try to find a class name using the loader constraints. The
2181 // loader constraints might know about a class that isn't fully loaded
2182 // yet and these will be ignored.
2183 Klass* SystemDictionary::find_constrained_instance_or_array_klass(
2184 Symbol* class_name, Handle class_loader, TRAPS) {
2185
2186 // First see if it has been loaded directly.
2187 // Force the protection domain to be null. (This removes protection checks.)
2188 Handle no_protection_domain;
2189 Klass* klass = find_instance_or_array_klass(class_name, class_loader,
2190 no_protection_domain, CHECK_NULL);
2191 if (klass != NULL)
2192 return klass;
2193
2194 // Now look to see if it has been loaded elsewhere, and is subject to
2195 // a loader constraint that would require this loader to return the
2196 // klass that is already loaded.
2197 if (FieldType::is_array(class_name)) {
2198 // For array classes, their Klass*s are not kept in the
2199 // constraint table. The element Klass*s are.
2200 FieldArrayInfo fd;
2201 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(NULL));
2202 if (t != T_OBJECT) {
2203 klass = Universe::typeArrayKlassObj(t);
2204 } else {
2205 MutexLocker mu(SystemDictionary_lock, THREAD);
2206 klass = constraints()->find_constrained_klass(fd.object_key(), class_loader);
2207 }
2208 // If element class already loaded, allocate array klass
2209 if (klass != NULL) {
2210 klass = klass->array_klass_or_null(fd.dimension());
2211 }
2212 } else {
2213 MutexLocker mu(SystemDictionary_lock, THREAD);
2214 // Non-array classes are easy: simply check the constraint table.
2215 klass = constraints()->find_constrained_klass(class_name, class_loader);
2216 }
2217
2218 return klass;
2219 }
2220
2221
2222 bool SystemDictionary::add_loader_constraint(Symbol* class_name,
2223 Handle class_loader1,
2224 Handle class_loader2,
2225 Thread* THREAD) {
2226 ClassLoaderData* loader_data1 = class_loader_data(class_loader1);
2227 ClassLoaderData* loader_data2 = class_loader_data(class_loader2);
2228
2229 Symbol* constraint_name = NULL;
2230 if (!FieldType::is_array(class_name)) {
2231 constraint_name = class_name;
2232 } else {
2233 // For array classes, their Klass*s are not kept in the
2234 // constraint table. The element classes are.
2235 FieldArrayInfo fd;
2236 BasicType t = FieldType::get_array_info(class_name, fd, CHECK_(false));
2237 // primitive types always pass
2238 if (t != T_OBJECT) {
2239 return true;
2240 } else {
2241 constraint_name = fd.object_key();
2242 }
2243 }
2244 unsigned int d_hash1 = dictionary()->compute_hash(constraint_name, loader_data1);
2245 int d_index1 = dictionary()->hash_to_index(d_hash1);
2246
2247 unsigned int d_hash2 = dictionary()->compute_hash(constraint_name, loader_data2);
2248 int d_index2 = dictionary()->hash_to_index(d_hash2);
2249 {
2250 MutexLocker mu_s(SystemDictionary_lock, THREAD);
2251
2252 // Better never do a GC while we're holding these oops
2253 No_Safepoint_Verifier nosafepoint;
2254
2255 Klass* klass1 = find_class(d_index1, d_hash1, constraint_name, loader_data1);
2256 Klass* klass2 = find_class(d_index2, d_hash2, constraint_name, loader_data2);
2257 return constraints()->add_entry(constraint_name, klass1, class_loader1,
2258 klass2, class_loader2);
2259 }
2260 }
2261
2262 // Add entry to resolution error table to record the error when the first
2263 // attempt to resolve a reference to a class has failed.
2264 void SystemDictionary::add_resolution_error(constantPoolHandle pool, int which, Symbol* error) {
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 resolution_errors()->add_entry(index, hash, pool, which, error);
2270 }
2271 }
2272
2273 // Delete a resolution error for RedefineClasses for a constant pool is going away
2274 void SystemDictionary::delete_resolution_error(ConstantPool* pool) {
2275 resolution_errors()->delete_entry(pool);
2276 }
2277
2278 // Lookup resolution error table. Returns error if found, otherwise NULL.
2279 Symbol* SystemDictionary::find_resolution_error(constantPoolHandle pool, int which) {
2280 unsigned int hash = resolution_errors()->compute_hash(pool, which);
2281 int index = resolution_errors()->hash_to_index(hash);
2282 {
2283 MutexLocker ml(SystemDictionary_lock, Thread::current());
2284 ResolutionErrorEntry* entry = resolution_errors()->find_entry(index, hash, pool, which);
2285 return (entry != NULL) ? entry->error() : (Symbol*)NULL;
2286 }
2287 }
2288
2289
2290 // Signature constraints ensure that callers and callees agree about
2291 // the meaning of type names in their signatures. This routine is the
2292 // intake for constraints. It collects them from several places:
2293 //
2294 // * LinkResolver::resolve_method (if check_access is true) requires
2295 // that the resolving class (the caller) and the defining class of
2296 // the resolved method (the callee) agree on each type in the
2297 // method's signature.
2298 //
2299 // * LinkResolver::resolve_interface_method performs exactly the same
2300 // checks.
2301 //
2302 // * LinkResolver::resolve_field requires that the constant pool
2303 // attempting to link to a field agree with the field's defining
2304 // class about the type of the field signature.
2305 //
2306 // * klassVtable::initialize_vtable requires that, when a class
2307 // overrides a vtable entry allocated by a superclass, that the
2308 // overriding method (i.e., the callee) agree with the superclass
2309 // on each type in the method's signature.
2310 //
2311 // * klassItable::initialize_itable requires that, when a class fills
2312 // in its itables, for each non-abstract method installed in an
2313 // itable, the method (i.e., the callee) agree with the interface
2314 // on each type in the method's signature.
2315 //
2316 // All those methods have a boolean (check_access, checkconstraints)
2317 // which turns off the checks. This is used from specialized contexts
2318 // such as bootstrapping, dumping, and debugging.
2319 //
2320 // No direct constraint is placed between the class and its
2321 // supertypes. Constraints are only placed along linked relations
2322 // between callers and callees. When a method overrides or implements
2323 // an abstract method in a supertype (superclass or interface), the
2324 // constraints are placed as if the supertype were the caller to the
2325 // overriding method. (This works well, since callers to the
2326 // supertype have already established agreement between themselves and
2327 // the supertype.) As a result of all this, a class can disagree with
2328 // its supertype about the meaning of a type name, as long as that
2329 // class neither calls a relevant method of the supertype, nor is
2330 // called (perhaps via an override) from the supertype.
2331 //
2332 //
2333 // SystemDictionary::check_signature_loaders(sig, l1, l2)
2334 //
2335 // Make sure all class components (including arrays) in the given
2336 // signature will be resolved to the same class in both loaders.
2337 // Returns the name of the type that failed a loader constraint check, or
2338 // NULL if no constraint failed. No exception except OOME is thrown.
2339 // Arrays are not added to the loader constraint table, their elements are.
2340 Symbol* SystemDictionary::check_signature_loaders(Symbol* signature,
2341 Handle loader1, Handle loader2,
2342 bool is_method, TRAPS) {
2343 // Nothing to do if loaders are the same.
2344 if (loader1() == loader2()) {
2345 return NULL;
2346 }
2347
2348 SignatureStream sig_strm(signature, is_method);
2349 while (!sig_strm.is_done()) {
2350 if (sig_strm.is_object()) {
2351 Symbol* sig = sig_strm.as_symbol(CHECK_NULL);
2352 if (!add_loader_constraint(sig, loader1, loader2, THREAD)) {
2353 return sig;
2354 }
2355 }
2356 sig_strm.next();
2357 }
2358 return NULL;
2359 }
2360
2361
2362 methodHandle SystemDictionary::find_method_handle_intrinsic(vmIntrinsics::ID iid,
2363 Symbol* signature,
2364 TRAPS) {
2365 methodHandle empty;
2366 assert(EnableInvokeDynamic, "");
2367 assert(MethodHandles::is_signature_polymorphic(iid) &&
2368 MethodHandles::is_signature_polymorphic_intrinsic(iid) &&
2369 iid != vmIntrinsics::_invokeGeneric,
2370 err_msg("must be a known MH intrinsic iid=%d: %s", iid, vmIntrinsics::name_at(iid)));
2371
2372 unsigned int hash = invoke_method_table()->compute_hash(signature, iid);
2373 int index = invoke_method_table()->hash_to_index(hash);
2374 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2375 methodHandle m;
2376 if (spe == NULL || spe->method() == NULL) {
2377 spe = NULL;
2378 // Must create lots of stuff here, but outside of the SystemDictionary lock.
2379 m = Method::make_method_handle_intrinsic(iid, signature, CHECK_(empty));
2380 if (!Arguments::is_interpreter_only()) {
2381 // Generate a compiled form of the MH intrinsic.
2382 AdapterHandlerLibrary::create_native_wrapper(m);
2383 // Check if have the compiled code.
2384 if (!m->has_compiled_code()) {
2385 THROW_MSG_(vmSymbols::java_lang_VirtualMachineError(),
2386 "out of space in CodeCache for method handle intrinsic", empty);
2387 }
2388 }
2389 // Now grab the lock. We might have to throw away the new method,
2390 // if a racing thread has managed to install one at the same time.
2391 {
2392 MutexLocker ml(SystemDictionary_lock, THREAD);
2393 spe = invoke_method_table()->find_entry(index, hash, signature, iid);
2394 if (spe == NULL)
2395 spe = invoke_method_table()->add_entry(index, hash, signature, iid);
2396 if (spe->method() == NULL)
2397 spe->set_method(m());
2398 }
2399 }
2400
2401 assert(spe != NULL && spe->method() != NULL, "");
2402 assert(Arguments::is_interpreter_only() || (spe->method()->has_compiled_code() &&
2403 spe->method()->code()->entry_point() == spe->method()->from_compiled_entry()),
2404 "MH intrinsic invariant");
2405 return spe->method();
2406 }
2407
2408 // Helper for unpacking the return value from linkMethod and linkCallSite.
2409 static methodHandle unpack_method_and_appendix(Handle mname,
2410 KlassHandle accessing_klass,
2411 objArrayHandle appendix_box,
2412 Handle* appendix_result,
2413 TRAPS) {
2414 methodHandle empty;
2415 if (mname.not_null()) {
2416 Metadata* vmtarget = java_lang_invoke_MemberName::vmtarget(mname());
2417 if (vmtarget != NULL && vmtarget->is_method()) {
2418 Method* m = (Method*)vmtarget;
2419 oop appendix = appendix_box->obj_at(0);
2420 if (TraceMethodHandles) {
2421 #ifndef PRODUCT
2422 tty->print("Linked method=" INTPTR_FORMAT ": ", p2i(m));
2423 m->print();
2424 if (appendix != NULL) { tty->print("appendix = "); appendix->print(); }
2425 tty->cr();
2426 #endif //PRODUCT
2427 }
2428 (*appendix_result) = Handle(THREAD, appendix);
2429 // the target is stored in the cpCache and if a reference to this
2430 // MethodName is dropped we need a way to make sure the
2431 // class_loader containing this method is kept alive.
2432 // FIXME: the appendix might also preserve this dependency.
2433 ClassLoaderData* this_key = InstanceKlass::cast(accessing_klass())->class_loader_data();
2434 this_key->record_dependency(m->method_holder(), CHECK_NULL); // Can throw OOM
2435 return methodHandle(THREAD, m);
2436 }
2437 }
2438 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad value from MethodHandleNatives", empty);
2439 return empty;
2440 }
2441
2442 methodHandle SystemDictionary::find_method_handle_invoker(Symbol* name,
2443 Symbol* signature,
2444 KlassHandle accessing_klass,
2445 Handle *appendix_result,
2446 Handle *method_type_result,
2447 TRAPS) {
2448 methodHandle empty;
2449 assert(EnableInvokeDynamic, "");
2450 assert(!THREAD->is_Compiler_thread(), "");
2451 Handle method_type =
2452 SystemDictionary::find_method_handle_type(signature, accessing_klass, CHECK_(empty));
2453
2454 KlassHandle mh_klass = SystemDictionary::MethodHandle_klass();
2455 int ref_kind = JVM_REF_invokeVirtual;
2456 Handle name_str = StringTable::intern(name, CHECK_(empty));
2457 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2458 assert(appendix_box->obj_at(0) == NULL, "");
2459
2460 // This should not happen. JDK code should take care of that.
2461 if (accessing_klass.is_null() || method_type.is_null()) {
2462 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokehandle", empty);
2463 }
2464
2465 // call java.lang.invoke.MethodHandleNatives::linkMethod(... String, MethodType) -> MemberName
2466 JavaCallArguments args;
2467 args.push_oop(accessing_klass()->java_mirror());
2468 args.push_int(ref_kind);
2469 args.push_oop(mh_klass()->java_mirror());
2470 args.push_oop(name_str());
2471 args.push_oop(method_type());
2472 args.push_oop(appendix_box());
2473 JavaValue result(T_OBJECT);
2474 JavaCalls::call_static(&result,
2475 SystemDictionary::MethodHandleNatives_klass(),
2476 vmSymbols::linkMethod_name(),
2477 vmSymbols::linkMethod_signature(),
2478 &args, CHECK_(empty));
2479 Handle mname(THREAD, (oop) result.get_jobject());
2480 (*method_type_result) = method_type;
2481 return unpack_method_and_appendix(mname, accessing_klass, appendix_box, appendix_result, THREAD);
2482 }
2483
2484 // Decide if we can globally cache a lookup of this class, to be returned to any client that asks.
2485 // We must ensure that all class loaders everywhere will reach this class, for any client.
2486 // This is a safe bet for public classes in java.lang, such as Object and String.
2487 // We also include public classes in java.lang.invoke, because they appear frequently in system-level method types.
2488 // Out of an abundance of caution, we do not include any other classes, not even for packages like java.util.
2489 static bool is_always_visible_class(oop mirror) {
2490 Klass* klass = java_lang_Class::as_Klass(mirror);
2491 if (klass->oop_is_objArray()) {
2492 klass = ObjArrayKlass::cast(klass)->bottom_klass(); // check element type
2493 }
2494 if (klass->oop_is_typeArray()) {
2495 return true; // primitive array
2496 }
2497 assert(klass->oop_is_instance(), klass->external_name());
2498 return klass->is_public() &&
2499 (InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::Object_klass()) || // java.lang
2500 InstanceKlass::cast(klass)->is_same_class_package(SystemDictionary::MethodHandle_klass())); // java.lang.invoke
2501 }
2502
2503 // Ask Java code to find or construct a java.lang.invoke.MethodType for the given
2504 // signature, as interpreted relative to the given class loader.
2505 // Because of class loader constraints, all method handle usage must be
2506 // consistent with this loader.
2507 Handle SystemDictionary::find_method_handle_type(Symbol* signature,
2508 KlassHandle accessing_klass,
2509 TRAPS) {
2510 Handle empty;
2511 vmIntrinsics::ID null_iid = vmIntrinsics::_none; // distinct from all method handle invoker intrinsics
2512 unsigned int hash = invoke_method_table()->compute_hash(signature, null_iid);
2513 int index = invoke_method_table()->hash_to_index(hash);
2514 SymbolPropertyEntry* spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2515 if (spe != NULL && spe->method_type() != NULL) {
2516 assert(java_lang_invoke_MethodType::is_instance(spe->method_type()), "");
2517 return Handle(THREAD, spe->method_type());
2518 } else if (THREAD->is_Compiler_thread()) {
2519 warning("SystemDictionary::find_method_handle_type called from compiler thread"); // FIXME
2520 return Handle(); // do not attempt from within compiler, unless it was cached
2521 }
2522
2523 Handle class_loader, protection_domain;
2524 if (accessing_klass.not_null()) {
2525 class_loader = Handle(THREAD, InstanceKlass::cast(accessing_klass())->class_loader());
2526 protection_domain = Handle(THREAD, InstanceKlass::cast(accessing_klass())->protection_domain());
2527 }
2528 bool can_be_cached = true;
2529 int npts = ArgumentCount(signature).size();
2530 objArrayHandle pts = oopFactory::new_objArray(SystemDictionary::Class_klass(), npts, CHECK_(empty));
2531 int arg = 0;
2532 Handle rt; // the return type from the signature
2533 ResourceMark rm(THREAD);
2534 for (SignatureStream ss(signature); !ss.is_done(); ss.next()) {
2535 oop mirror = NULL;
2536 if (can_be_cached) {
2537 // Use neutral class loader to lookup candidate classes to be placed in the cache.
2538 mirror = ss.as_java_mirror(Handle(), Handle(),
2539 SignatureStream::ReturnNull, CHECK_(empty));
2540 if (mirror == NULL || (ss.is_object() && !is_always_visible_class(mirror))) {
2541 // Fall back to accessing_klass context.
2542 can_be_cached = false;
2543 }
2544 }
2545 if (!can_be_cached) {
2546 // Resolve, throwing a real error if it doesn't work.
2547 mirror = ss.as_java_mirror(class_loader, protection_domain,
2548 SignatureStream::NCDFError, CHECK_(empty));
2549 }
2550 assert(!oopDesc::is_null(mirror), ss.as_symbol(THREAD)->as_C_string());
2551 if (ss.at_return_type())
2552 rt = Handle(THREAD, mirror);
2553 else
2554 pts->obj_at_put(arg++, mirror);
2555
2556 // Check accessibility.
2557 if (ss.is_object() && accessing_klass.not_null()) {
2558 Klass* sel_klass = java_lang_Class::as_Klass(mirror);
2559 mirror = NULL; // safety
2560 // Emulate ConstantPool::verify_constant_pool_resolve.
2561 if (sel_klass->oop_is_objArray())
2562 sel_klass = ObjArrayKlass::cast(sel_klass)->bottom_klass();
2563 if (sel_klass->oop_is_instance()) {
2564 KlassHandle sel_kh(THREAD, sel_klass);
2565 LinkResolver::check_klass_accessability(accessing_klass, sel_kh, CHECK_(empty));
2566 }
2567 }
2568 }
2569 assert(arg == npts, "");
2570
2571 // call java.lang.invoke.MethodHandleNatives::findMethodType(Class rt, Class[] pts) -> MethodType
2572 JavaCallArguments args(Handle(THREAD, rt()));
2573 args.push_oop(pts());
2574 JavaValue result(T_OBJECT);
2575 JavaCalls::call_static(&result,
2576 SystemDictionary::MethodHandleNatives_klass(),
2577 vmSymbols::findMethodHandleType_name(),
2578 vmSymbols::findMethodHandleType_signature(),
2579 &args, CHECK_(empty));
2580 Handle method_type(THREAD, (oop) result.get_jobject());
2581
2582 if (can_be_cached) {
2583 // We can cache this MethodType inside the JVM.
2584 MutexLocker ml(SystemDictionary_lock, THREAD);
2585 spe = invoke_method_table()->find_entry(index, hash, signature, null_iid);
2586 if (spe == NULL)
2587 spe = invoke_method_table()->add_entry(index, hash, signature, null_iid);
2588 if (spe->method_type() == NULL) {
2589 spe->set_method_type(method_type());
2590 }
2591 }
2592
2593 // report back to the caller with the MethodType
2594 return method_type;
2595 }
2596
2597 // Ask Java code to find or construct a method handle constant.
2598 Handle SystemDictionary::link_method_handle_constant(KlassHandle caller,
2599 int ref_kind, //e.g., JVM_REF_invokeVirtual
2600 KlassHandle callee,
2601 Symbol* name_sym,
2602 Symbol* signature,
2603 TRAPS) {
2604 Handle empty;
2605 Handle name = java_lang_String::create_from_symbol(name_sym, CHECK_(empty));
2606 Handle type;
2607 if (signature->utf8_length() > 0 && signature->byte_at(0) == '(') {
2608 type = find_method_handle_type(signature, caller, CHECK_(empty));
2609 } else if (caller.is_null()) {
2610 // This should not happen. JDK code should take care of that.
2611 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad MH constant", empty);
2612 } else {
2613 ResourceMark rm(THREAD);
2614 SignatureStream ss(signature, false);
2615 if (!ss.is_done()) {
2616 oop mirror = ss.as_java_mirror(caller->class_loader(), caller->protection_domain(),
2617 SignatureStream::NCDFError, CHECK_(empty));
2618 type = Handle(THREAD, mirror);
2619 ss.next();
2620 if (!ss.is_done()) type = Handle(); // error!
2621 }
2622 }
2623 if (type.is_null()) {
2624 THROW_MSG_(vmSymbols::java_lang_LinkageError(), "bad signature", empty);
2625 }
2626
2627 // call java.lang.invoke.MethodHandleNatives::linkMethodHandleConstant(Class caller, int refKind, Class callee, String name, Object type) -> MethodHandle
2628 JavaCallArguments args;
2629 args.push_oop(caller->java_mirror()); // the referring class
2630 args.push_int(ref_kind);
2631 args.push_oop(callee->java_mirror()); // the target class
2632 args.push_oop(name());
2633 args.push_oop(type());
2634 JavaValue result(T_OBJECT);
2635 JavaCalls::call_static(&result,
2636 SystemDictionary::MethodHandleNatives_klass(),
2637 vmSymbols::linkMethodHandleConstant_name(),
2638 vmSymbols::linkMethodHandleConstant_signature(),
2639 &args, CHECK_(empty));
2640 return Handle(THREAD, (oop) result.get_jobject());
2641 }
2642
2643 // Ask Java code to find or construct a java.lang.invoke.CallSite for the given
2644 // name and signature, as interpreted relative to the given class loader.
2645 methodHandle SystemDictionary::find_dynamic_call_site_invoker(KlassHandle caller,
2646 Handle bootstrap_specifier,
2647 Symbol* name,
2648 Symbol* type,
2649 Handle *appendix_result,
2650 Handle *method_type_result,
2651 TRAPS) {
2652 methodHandle empty;
2653 Handle bsm, info;
2654 if (java_lang_invoke_MethodHandle::is_instance(bootstrap_specifier())) {
2655 bsm = bootstrap_specifier;
2656 } else {
2657 assert(bootstrap_specifier->is_objArray(), "");
2658 objArrayHandle args(THREAD, (objArrayOop) bootstrap_specifier());
2659 int len = args->length();
2660 assert(len >= 1, "");
2661 bsm = Handle(THREAD, args->obj_at(0));
2662 if (len > 1) {
2663 objArrayOop args1 = oopFactory::new_objArray(SystemDictionary::Object_klass(), len-1, CHECK_(empty));
2664 for (int i = 1; i < len; i++)
2665 args1->obj_at_put(i-1, args->obj_at(i));
2666 info = Handle(THREAD, args1);
2667 }
2668 }
2669 guarantee(java_lang_invoke_MethodHandle::is_instance(bsm()),
2670 "caller must supply a valid BSM");
2671
2672 Handle method_name = java_lang_String::create_from_symbol(name, CHECK_(empty));
2673 Handle method_type = find_method_handle_type(type, caller, CHECK_(empty));
2674
2675 // This should not happen. JDK code should take care of that.
2676 if (caller.is_null() || method_type.is_null()) {
2677 THROW_MSG_(vmSymbols::java_lang_InternalError(), "bad invokedynamic", empty);
2678 }
2679
2680 objArrayHandle appendix_box = oopFactory::new_objArray(SystemDictionary::Object_klass(), 1, CHECK_(empty));
2681 assert(appendix_box->obj_at(0) == NULL, "");
2682
2683 // call java.lang.invoke.MethodHandleNatives::linkCallSite(caller, bsm, name, mtype, info, &appendix)
2684 JavaCallArguments args;
2685 args.push_oop(caller->java_mirror());
2686 args.push_oop(bsm());
2687 args.push_oop(method_name());
2688 args.push_oop(method_type());
2689 args.push_oop(info());
2690 args.push_oop(appendix_box);
2691 JavaValue result(T_OBJECT);
2692 JavaCalls::call_static(&result,
2693 SystemDictionary::MethodHandleNatives_klass(),
2694 vmSymbols::linkCallSite_name(),
2695 vmSymbols::linkCallSite_signature(),
2696 &args, CHECK_(empty));
2697 Handle mname(THREAD, (oop) result.get_jobject());
2698 (*method_type_result) = method_type;
2699 return unpack_method_and_appendix(mname, caller, appendix_box, appendix_result, THREAD);
2700 }
2701
2702 // Since the identity hash code for symbols changes when the symbols are
2703 // moved from the regular perm gen (hash in the mark word) to the shared
2704 // spaces (hash is the address), the classes loaded into the dictionary
2705 // may be in the wrong buckets.
2706
2707 void SystemDictionary::reorder_dictionary() {
2708 dictionary()->reorder_dictionary();
2709 }
2710
2711
2712 void SystemDictionary::copy_buckets(char** top, char* end) {
2713 dictionary()->copy_buckets(top, end);
2714 }
2715
2716
2717 void SystemDictionary::copy_table(char** top, char* end) {
2718 dictionary()->copy_table(top, end);
2719 }
2720
2721
2722 void SystemDictionary::reverse() {
2723 dictionary()->reverse();
2724 }
2725
2726 int SystemDictionary::number_of_classes() {
2727 return dictionary()->number_of_entries();
2728 }
2729
2730
2731 // ----------------------------------------------------------------------------
2732 void SystemDictionary::print_shared(bool details) {
2733 shared_dictionary()->print(details);
2734 }
2735
2736 void SystemDictionary::print(bool details) {
2737 dictionary()->print(details);
2738
2739 // Placeholders
2740 GCMutexLocker mu(SystemDictionary_lock);
2741 placeholders()->print();
2742
2743 // loader constraints - print under SD_lock
2744 constraints()->print();
2745 }
2746
2747
2748 void SystemDictionary::verify() {
2749 guarantee(dictionary() != NULL, "Verify of system dictionary failed");
2750 guarantee(constraints() != NULL,
2751 "Verify of loader constraints failed");
2752 guarantee(dictionary()->number_of_entries() >= 0 &&
2753 placeholders()->number_of_entries() >= 0,
2754 "Verify of system dictionary failed");
2755
2756 // Verify dictionary
2757 dictionary()->verify();
2758
2759 GCMutexLocker mu(SystemDictionary_lock);
2760 placeholders()->verify();
2761
2762 // Verify constraint table
2763 guarantee(constraints() != NULL, "Verify of loader constraints failed");
2764 constraints()->verify(dictionary(), placeholders());
2765 }
2766
2767 #ifndef PRODUCT
2768
2769 // statistics code
2770 class ClassStatistics: AllStatic {
2771 private:
2772 static int nclasses; // number of classes
2773 static int nmethods; // number of methods
2774 static int nmethoddata; // number of methodData
2775 static int class_size; // size of class objects in words
2776 static int method_size; // size of method objects in words
2777 static int debug_size; // size of debug info in methods
2778 static int methoddata_size; // size of methodData objects in words
2779
2780 static void do_class(Klass* k) {
2781 nclasses++;
2782 class_size += k->size();
2783 if (k->oop_is_instance()) {
2784 InstanceKlass* ik = (InstanceKlass*)k;
2785 class_size += ik->methods()->size();
2786 class_size += ik->constants()->size();
2787 class_size += ik->local_interfaces()->size();
2788 class_size += ik->transitive_interfaces()->size();
2789 // We do not have to count implementors, since we only store one!
2790 // SSS: How should these be accounted now that they have moved?
2791 // class_size += ik->fields()->length();
2792 }
2793 }
2794
2795 static void do_method(Method* m) {
2796 nmethods++;
2797 method_size += m->size();
2798 // class loader uses same objArray for empty vectors, so don't count these
2799 if (m->has_stackmap_table()) {
2800 method_size += m->stackmap_data()->size();
2801 }
2802
2803 MethodData* mdo = m->method_data();
2804 if (mdo != NULL) {
2805 nmethoddata++;
2806 methoddata_size += mdo->size();
2807 }
2808 }
2809
2810 public:
2811 static void print() {
2812 SystemDictionary::classes_do(do_class);
2813 SystemDictionary::methods_do(do_method);
2814 tty->print_cr("Class statistics:");
2815 tty->print_cr("%d classes (%d bytes)", nclasses, class_size * oopSize);
2816 tty->print_cr("%d methods (%d bytes = %d base + %d debug info)", nmethods,
2817 (method_size + debug_size) * oopSize, method_size * oopSize, debug_size * oopSize);
2818 tty->print_cr("%d methoddata (%d bytes)", nmethoddata, methoddata_size * oopSize);
2819 }
2820 };
2821
2822
2823 int ClassStatistics::nclasses = 0;
2824 int ClassStatistics::nmethods = 0;
2825 int ClassStatistics::nmethoddata = 0;
2826 int ClassStatistics::class_size = 0;
2827 int ClassStatistics::method_size = 0;
2828 int ClassStatistics::debug_size = 0;
2829 int ClassStatistics::methoddata_size = 0;
2830
2831 void SystemDictionary::print_class_statistics() {
2832 ResourceMark rm;
2833 ClassStatistics::print();
2834 }
2835
2836
2837 class MethodStatistics: AllStatic {
2838 public:
2839 enum {
2840 max_parameter_size = 10
2841 };
2842 private:
2843
2844 static int _number_of_methods;
2845 static int _number_of_final_methods;
2846 static int _number_of_static_methods;
2847 static int _number_of_native_methods;
2848 static int _number_of_synchronized_methods;
2849 static int _number_of_profiled_methods;
2850 static int _number_of_bytecodes;
2851 static int _parameter_size_profile[max_parameter_size];
2852 static int _bytecodes_profile[Bytecodes::number_of_java_codes];
2853
2854 static void initialize() {
2855 _number_of_methods = 0;
2856 _number_of_final_methods = 0;
2857 _number_of_static_methods = 0;
2858 _number_of_native_methods = 0;
2859 _number_of_synchronized_methods = 0;
2860 _number_of_profiled_methods = 0;
2861 _number_of_bytecodes = 0;
2862 for (int i = 0; i < max_parameter_size ; i++) _parameter_size_profile[i] = 0;
2863 for (int j = 0; j < Bytecodes::number_of_java_codes; j++) _bytecodes_profile [j] = 0;
2864 };
2865
2866 static void do_method(Method* m) {
2867 _number_of_methods++;
2868 // collect flag info
2869 if (m->is_final() ) _number_of_final_methods++;
2870 if (m->is_static() ) _number_of_static_methods++;
2871 if (m->is_native() ) _number_of_native_methods++;
2872 if (m->is_synchronized()) _number_of_synchronized_methods++;
2873 if (m->method_data() != NULL) _number_of_profiled_methods++;
2874 // collect parameter size info (add one for receiver, if any)
2875 _parameter_size_profile[MIN2(m->size_of_parameters() + (m->is_static() ? 0 : 1), max_parameter_size - 1)]++;
2876 // collect bytecodes info
2877 {
2878 Thread *thread = Thread::current();
2879 HandleMark hm(thread);
2880 BytecodeStream s(methodHandle(thread, m));
2881 Bytecodes::Code c;
2882 while ((c = s.next()) >= 0) {
2883 _number_of_bytecodes++;
2884 _bytecodes_profile[c]++;
2885 }
2886 }
2887 }
2888
2889 public:
2890 static void print() {
2891 initialize();
2892 SystemDictionary::methods_do(do_method);
2893 // generate output
2894 tty->cr();
2895 tty->print_cr("Method statistics (static):");
2896 // flag distribution
2897 tty->cr();
2898 tty->print_cr("%6d final methods %6.1f%%", _number_of_final_methods , _number_of_final_methods * 100.0F / _number_of_methods);
2899 tty->print_cr("%6d static methods %6.1f%%", _number_of_static_methods , _number_of_static_methods * 100.0F / _number_of_methods);
2900 tty->print_cr("%6d native methods %6.1f%%", _number_of_native_methods , _number_of_native_methods * 100.0F / _number_of_methods);
2901 tty->print_cr("%6d synchronized methods %6.1f%%", _number_of_synchronized_methods, _number_of_synchronized_methods * 100.0F / _number_of_methods);
2902 tty->print_cr("%6d profiled methods %6.1f%%", _number_of_profiled_methods, _number_of_profiled_methods * 100.0F / _number_of_methods);
2903 // parameter size profile
2904 tty->cr();
2905 { int tot = 0;
2906 int avg = 0;
2907 for (int i = 0; i < max_parameter_size; i++) {
2908 int n = _parameter_size_profile[i];
2909 tot += n;
2910 avg += n*i;
2911 tty->print_cr("parameter size = %1d: %6d methods %5.1f%%", i, n, n * 100.0F / _number_of_methods);
2912 }
2913 assert(tot == _number_of_methods, "should be the same");
2914 tty->print_cr(" %6d methods 100.0%%", _number_of_methods);
2915 tty->print_cr("(average parameter size = %3.1f including receiver, if any)", (float)avg / _number_of_methods);
2916 }
2917 // bytecodes profile
2918 tty->cr();
2919 { int tot = 0;
2920 for (int i = 0; i < Bytecodes::number_of_java_codes; i++) {
2921 if (Bytecodes::is_defined(i)) {
2922 Bytecodes::Code c = Bytecodes::cast(i);
2923 int n = _bytecodes_profile[c];
2924 tot += n;
2925 tty->print_cr("%9d %7.3f%% %s", n, n * 100.0F / _number_of_bytecodes, Bytecodes::name(c));
2926 }
2927 }
2928 assert(tot == _number_of_bytecodes, "should be the same");
2929 tty->print_cr("%9d 100.000%%", _number_of_bytecodes);
2930 }
2931 tty->cr();
2932 }
2933 };
2934
2935 int MethodStatistics::_number_of_methods;
2936 int MethodStatistics::_number_of_final_methods;
2937 int MethodStatistics::_number_of_static_methods;
2938 int MethodStatistics::_number_of_native_methods;
2939 int MethodStatistics::_number_of_synchronized_methods;
2940 int MethodStatistics::_number_of_profiled_methods;
2941 int MethodStatistics::_number_of_bytecodes;
2942 int MethodStatistics::_parameter_size_profile[MethodStatistics::max_parameter_size];
2943 int MethodStatistics::_bytecodes_profile[Bytecodes::number_of_java_codes];
2944
2945
2946 void SystemDictionary::print_method_statistics() {
2947 MethodStatistics::print();
2948 }
2949
2950 #endif // PRODUCT